Full text of "Automobile Engineering"

See other formats

This is a digital copy of a book that was preserved for generations on library shelves before it was carefully scanned by Google as part of a project
to make the world's books discoverable online.

It has survived long enough for the copyright to expire and the book to enter the public domain. A public domain book is one that was never subject
to copyright or whose legal copyright term has expired. Whether a book is in the public domain may vary country to country. Public domain books
are our gateways to the past, representing a wealth of history, culture and knowledge that's often difficult to discover.

Marks, notations and other marginalia present in the original volume will appear in this file - a reminder of this book's long journey from the
publisher to a library and finally to you.

Usage guidelines

Google is proud to partner with libraries to digitize public domain materials and make them widely accessible. Public domain books belong to the
public and we are merely their custodians. Nevertheless, this work is expensive, so in order to keep providing this resource, we have taken steps to
prevent abuse by commercial parties, including placing technical restrictions on automated querying.

We also ask that you:

+ Make non- commercial use of the files We designed Google Book Search for use by individuals, and we request that you use these files for
personal, non-commercial purposes.

+ Refrain from automated querying Do not send automated queries of any sort to Google's system: If you are conducting research on machine
translation, optical character recognition or other areas where access to a large amount of text is helpful, please contact us. We encourage the
use of public domain materials for these purposes and may be able to help.

+ Maintain attribution The Google "watermark" you see on each file is essential for informing people about this project and helping them find
additional materials through Google Book Search. Please do not remove it.

+ Keep it legal Whatever your use, remember that you are responsible for ensuring that what you are doing is legal. Do not assume that just
because we believe a book is in the public domain for users in the United States, that the work is also in the public domain for users in other
countries. Whether a book is still in copyright varies from country to country, and we can't offer guidance on whether any specific use of
any specific book is allowed. Please do not assume that a book's appearance in Google Book Search means it can be used in any manner
anywhere in the world. Copyright infringement liability can be quite severe.

About Google Book Search

Google's mission is to organize the world's information and to make it universally accessible and useful. Google Book Search helps readers
discover the world's books while helping authors and publishers reach new audiences. You can search through the full text of this book on the web

at http : //books . qooqle . com/|

Digitized by

Google

Digitized by

Google

Digitized by

Google

Digitized by

Google

Digitized by

Google

« s.
° I
« °

Digitized by

Google

Automobile
Engineering

./ (ieaeral Rcfrmur U'.rk

FOR REPAIR MEN, CHAUFFEURS, AND OWNERS; COVERING THE CONSTRUCTION,

CARE, AND REPAIR OF PLEASURE CARS, COMMERCIAL CARS, AND

MOTORCYCLES, WITH ESPECIAL ATTENTION TO IGNITION,

STARTING, AND LIGHTING SYSTEMS, GARAGE DESIGN

AND EQUIPMENT, WELDING, AND OTHER

REPAIR METHODS

Prepared by a Staff of

AUTOMOBILE EXPERTS, CONSULTING ENGINEERS, AND DESIGNERS OF THE
HIGHEST PROFESSIONAL STANDING

Illustrated -with o:\ r llf'ieni J lima' rid Eu[rravhv>

SIX VOLUMES

AMERICAN TECHNICAL SOCIETY
CHICAGO

Digitized by

Google

K B t> - --

r c

liY

AMERICAN TECHNICAL SOCIETY

Copyrighted in Great Britain
All Rights Reserved

Digitized by

Google

Authors and Collaborators

CHARLES B. HAYWARD

President and General Manager, The Stirling Press, Now York City

Member, Society of Automobile Engineer*

Member, The Aeronautical Society

Formerly Secretary, Society of Automobile Engineers

Formerly Engineering Editor, The Automobile

C. T. ZIEGLER

Automobile Engineer

With Inter-Stnto Motor Company, M uncle, Indiana

Formerly Manager, The Ziegler Company, Chicago

MORRIS A. HALL

Editor, Automotive Engineering

Formerly Managing Editor Motor Life, Editor The Commercial Vehicle, etc.

Author of "What Every Automobile Owner Should Know"

Member, Society of Automobile Engineers

Member, American Society of Mechanical Engineers

DARWIN S. HATCH, B.S.

Editor, Motor Age, Chicago
Formerly Managing Editor, The Light Car
MemlK'r, Society of Automobile Engineers
American Automobile Association

GLENN M. HOBBS, Ph.D.

Secretary and Educational Director, American School of Correspondence
Formerly Instructor in Physics, The University of Chicago
American Physical Society

HERBERT L. CONNELL, B.S.E.

Late Lecturer, Automobile Division, Milwaukee Central Continuation School
Editorial Representative, Commercial Car Journal and Automobile Trade Journal
Member, Society of Automobile Engineers
Member, Standards Committee of S. A. E.
Formerly Technical Editor, The Light Car

Digitized by

Google

Authors and Collaborators— Continued

HUGO DIEMER, M.E.

Professor of Industrial Engineering, Pennsylvania State College
American Society of Mechanical Engineers

HERBERT LADD TOWLE, B.A.

Specialist in Technical Advertising
Member, Society of Automobile Engineers
Formerly Associate Editor, The Automobile

ROBERT J. KEHL, M.E.

Consulting Mechanical Engineer, Chicago
American Society of Mechanical Engineers

EDMOXD M. SIMON, B.S.

Superintendent Union Malleable Iron Company, East Mollne, Illinois

EDWARD B. WAITE

Formerly Dean and Head, Consulting Department, American School of

Correspondence •

Member, American Society of Mechanical Engineers

C. A. MILLER, JR.

Associate Editor, American Technical Society
Formerly Managing Editor of Xational Builder
Member, American Association of Engineers

W. R. HOWELL

President, W. It. Howell and Company, London, England

WILLIAM K. GIBBS, B.S.

Associate Editor, Motor Af/r. Chicago

JESSIE M. SHEPHERD, A.B.

Head, Publication Department, American Technical Society

Digitized by

Google

Authorities Consulted

THE editors have freely consulted the standard technical litera-
ture of America and Europe in the preparation of these
volumes. They desire to express their indebtedness, particu-
larly, to the following eminent authorities, whose well-known treatises
should be in the library of everyone interested in the Automobile and
allied subjects.

Grateful acknowledgment- is here made also for the invaluable
co-operation of the foremost Automobile Firms and Manufacturer?
in making these volumes thoroughly representative of the very latest
and best practice in the design, construction, and operation of Auto-
mobiles, Commercial Vehicles, Motorcycles, Motor Boats, etc. ; also
for the valuable drawings, data, illustrations, suggestions, criticisms,
and other courtesies.

CHARLES E. DURYEA

Consulting Engineer

First Vice-President, American Motor League

Author of "Roadside Troubles"

OCTAVE CHANUTE

Late Consulting Engineer

Past President of the American Society of Civil Engineers

Author of "Artificial Flight," etc.

E. W. ROBERTS, M.E.

Member, American Society of Mechanical Engineers

Author of "Gas-Engine Handbook," "Gas Engines and Their Troubles," "The
Automobile Pocket-BooU," etc.

SANFORD A. MOSS, M.S., Ph.D.

Member, American Society of Mechanical Engineers
Engineer, General Electric Company
Author of "Elements of Gas Engine Design"

GARDNER D. HISCOX, M.E.

Author of "Horseless Vehicles, Automobiles, and Motorcycles," "Gas, Gasoline,
and Oil Engines," "Mechanical Movements, Powers, and Devices," etc.

AUGUSTUS TREADWELL, Jr., E.E.

Associate Member, American Institute of Electrical Engineers
Author of "The Storage Battery : A Practical Treatise on the Construction,
Theory, and Use of Secondary Batteries"

Digitized by

Google

Authorities Consulted— Continued

BENJAMIN R. TILLSON

Director, H. J. Willard Company Automobile School
Author of "The Complete Automobile Instructor"

>•

THOMAS H. RUSSELL, M.E., LL.B.

Editor, The American Cyclopedia of the Automobile

Author of "Motor Boats," "History of the Automobile." "Automobile Driving.

Self -Taught." "Automobile Motors and Mechanism," "Ignition Timing and

Valve Setting," etc.

CHARLES EDWARD LUCRE, Ph.D.

Mechanical Engineering Department, Columbia University
Author of "Cas Engine Design"

P. M. HELDT

Editor, IlornelettM Age

Author of "The (iasollne Automobile"

H. D1EDERICHS, M.B.

Professor of Experimental Engineering. Sibley College. Cornell University
Author of "Internal Combustion Engines"

JOHN HENRY KNIGHT

Author of "Light Motor Cars and Yoiturettes," "Motor Hep'Uring for Ama-
teurs," etc.

>•
WM. ROBINSON, M.E.

I'rofessor of Meehanieal and Eleetrleal Engineering in T'niversity College. Not-
tingham
Author of "(Jas and Petroleum Engines"

\V. POYNTER ADAMS

Member. Institution of Automobile Engineers
Author of "Motor-Car Meehanisms and Management"

ROLLA C. CARPENTER, M.M.E., LL.D.

Professor of Experimental Engineering. Sibley College, Cornell University
Author of "Internal Combustion Engines"

ROGER B. WHITMAN

Technical Director. The New York School of Automobile Engineers
Author of "Motor-Car Principles"

Digitized by

Google

Authorities Consulted— Continued

CHARLES P. ROOT

Formerly Editor, Motor Age

Author of "Automobile Troubles, and How to Remedy Them"

W. HILBERT

Associate Member, Institute of Electrical Engineers
Author of "Electric Ignition for Motor Vehicles"

SIR HIRAM MAXIM

Member, American Society of Civil Engineers
Uritish Association for the Advancement of Science
Chevalier Legion d'llonneur
Author of "Artificial and Natural Flight," etc.

SIGMUND KRAUSZ

Author of "Complete Automobile Record," "A H C of Motoring"

JOHN GEDDES McINTOSH

Lecturer on Manufacture and Application of Industrial Alcohol, at the Poly-
technic Institute, London
Author of "Industrial Alcohol," etc.

FREDERICK GROVER, A.M., Inst.C.E., M.I.Mech.E.

Consulting Engineer

Author of "Modern <!as and Oil Engines"

FRANCIS B. CROCKER, M.E., Ph.D.

Head of Department of Electrical Engineering, Columbia Enlverslty
Past President, American Institute of Electrical Engineers

Author of "Electric Lighting," Joint Author of "Management of Electrical
Machinery"

A. HILDEBRANDT

Captain and Instructor In the Prussian Aeronautic Corps
Author of "Airships Past and Present"

T. HYLER WHITE

Associate Member, Institute of Mechanical Engineers
Author of "Petrol Motors and Motor Cars"

Digitized by

Google

Authorities Consulted— Continued

ROBERT H. THURSTON, C.E., Ph.B.. A.M., LL.D.

Director of Sibley College, Cornell University

Author of "Manual of the Steam Engine," "Manual of Steam Hollers," et<*«

MAX PEMBERTON

Motoring Editor, The London Sphere
Author of "The Amateur Motorist"

HERMAN W. L. MOEDEBECK

Major and Battalions Konimandeur In Badischcn Kussnrt Merle
Author of "Pocket-Book of Aeronautics"

EDWARD F. MILLER

Professor of Steam Engineering, Massachusetts Institute of Technology
Author of "Steam Boilers"

ALBERT L. CLOUGH

Author of "Operation, Care, nnd Repair of Automobiles"

W. F. DURAND

Author of "Motor Boats." etc.

PAUL N. HASLUCK

Editor, Work and Building ^Yorld
Author of "Motorcycle Building"

V-

JAMES E. HOMANS, A.M.

Author of "Self-Propelled Vehicles"

R. R. MECREDY

Editor, The Encyclopedia of Motoring, Motor Xctrs, vte.

S. R. BOTTONE

Author of "Ignition Devices," "Magnetos for Automobiles." etc.

LAMAR LYNDON, B.E., M.E.

Consulting Electrical Engineer

Associate Member, American Institute of Electrical Engineers

Author of "Storage Battery Engineering"

Digitized by

Google

K -2

« ^
co ^

P *

Digitized by

Google

B 8.

< s
Si

° H.
* s

Digitized by

Google

Foreword

THE period of evolution of the automobile does not
span many years, but the evolution has been none
the less spectacular and complete. From a creature
of sudden caprices and uncertain behavior, it has become
today a well-behaved thoroughbred of known habits and
perfect reliability. The driver no longer needs to carry war
clothes in momentary expectation of a call to the front.
He sits in his seat, starts his motor by pressing a button
with his hand or foot, and probably for weeks on end will
not need to do anything more serious than feed his animal
gasoline or oil, screw up a few grease cups, and pump up a
tire or two.

C, And yety the traveling along this road of reliability and
mechanical perfection has not been easy, and the grades
have not been negotiated or the heights reached without
many trials and failures. The application of the internal-
combustion motor, the electric motor, the storage battery,
and the steam engine to the development of the modern
types of mechanically propelled road carriages, has been a
far-reaching, engineering problem of great difficulty.
Nevertheless, through the aid of the best scientific and me-
chanical minds in this and other countries, every detail
has received the amount of attention necessary to make it
as perfect as possible. Eoad troubles, except in connection
with tires, have become almost negligible and even the
inexperienced driver, who knows barely enough to keep to the
road and shift gears properly, can venture on long touring
trips without fear of getting stranded. The refinements
in the ignition, starting, and lighting systems have added
greatly to the pleasure in running the car. Altogether, the
automobile as a whole has become standardized, and unless
some unforeseen developments are brought about, future
changes in either the gasoline or the electric automobile
will be merely along the line of greater refinement of the
mechanical and electrical devices used.

Digitized by

Google

^ Notwithstanding the high degree of reliability already
spoken of, the ears, as they get, older, will need the atten-
tion of the repair man. This is particularly true of the
tars two and three seasons old. A special effort, therefore,
has been made to furnish information which will be of value
to the men whose duty it is to revive the faltering action of
the motor and to take care of the other internal troubles
in the machine.

^ Special effort has been made to emphasize the treatment
of the Electrical Equipment of Gasoline Cars, not only be-
cause it is in this direction that most of the improvements
have lately taken place, but also because this department of
automobile construction is least familiar to the repair men
and others interested in the details of the automobile. A
multitude of diagrams have been supplied showing the con-
structive features and wiring circuits of the principal sys-
tems. In addition to this instructive section, particular
attention is called to the articles on Welding, Shop Tn- l
formation, and Garage Design and Equipment.

Digitized by

Google

Table of Contents

VOLUME II
Gasoline Automobiles (continued) . By Morris A. Hall\ Page *11

Clutches: Classification, Cone Type, Contracting-Band Type, Expanding-
Band Type. Disc Type, Magnetic Type — Clutch Operation: Methods,
Gradual Release, Lubrication, Bearings, Adjustment, Accessibility, Clutch
Troubles and Remedies (Slipping Clutch, Clutch Leathers, Clutch Springs,
Fierce Clutch, Spinning, Cork Inserts, Adjusting Clutch Pedals, Summary
of Troubles) — Transmissions: Classification, Sliding Gear (Selective, Pro-
gressive, Modern Selective, Transmission Location, Interlocking Devices.
Electrically Operated Gears, Pneumatic Shifting System), Individual
Clutch, Planetary Gears (Method of Action, Ford Planetary Type), Fric-
tion Disc (Spur Type, Bevel Type), Miscellaneous (Freak Drives, Cable
and Rope, Hydraulic, Pneumatic. Electric, Electric Transmissions), Trans-
mission Troubles and Repairs (Heating, Gear Pullers. Pressing Gears on
Shafts, Diagnosis, Poor Gear Shifting, Cleaning Gears, Transmission
Stands, Transmission Troubles) — Gears: Types of Gear-Cutting Machines
(Whiton, Brown and Sharpe, Automatic, Becker, Fellows, Gleason, Bil-
gram), Types of Gears in Automobiles (Spur, Bevel, Helical, and Herring-
bone, Spiral, Spiral-Bevel, Worm) — Questions and Answers — Steering
Group: Steering Gears: Front Axle Steering, Characteristics of Steering
Gears, Spur and Bevel Type, Worm Gear Type, Ford Steering Gear, Semi- •
Reversible Gear, Steering-Gear Assembly Troubles and Repairs — Steering
Wheels — Steering Rods — Special Types of Drive: Front- Wheel Drive,
* Four-Wheel Drive, Four-Wheel Steering Arrangement, Electric Drive —
Front Axles: Classification, Elliott Type, Reversed Elliott Type, Le-
moine Type, Materials, Axle Bearings, Front Axle Troubles and Repairs —
Chassis Group: Frames: Pressed-Steel Frame, Sub-Frames, Types of
Frames, Frame Troubles and Repairs — Springs: Semi-Elliptic, Three-
Quarter Elliptic, Platform, Cantilever, Hotchkiss, Unconventional Types,
Spring Troubles and Remedies — Shock Absorbers — Questions and Answers
— Final-Drive Group: Rear Axle: Units and Final Drive, Universal
Joints, Final Drives, Torque Bar and Its Function, Driving- Reaction.
Types of Rear Axles, Rear- Axle Troubles and Repairs — Brakes: Classifi-
cation, External-Contracting Brakes, Internal-Expanding Brakes, Double
Brake Drum for Safety, Brake Operation, Adjustments, Lubrication,
Electric Brakes, Hydraulic Brakes, Vacuum Brakes, Brake Troubles and
Repairs— Wheels: Pleasure-Car Wheels, Commercial-Car Wheels. Wheel
Troubles and Repairs — Tires: Classification, Tire Pressures, Changing
Tires, Recent Improvements — Rims: Plain Rims. Clincher Rims, Quick-
Detachable Rims, Standard Sizes of Tires and Rims, Tire Construction,
Tire Repairs, Vulcanization of Tires, Types of Vulcanizing Outfits, Vul-
canizing Kettles, Inside Casing Forms, Side Wall Vulcanlzer, Layouts of
Equipment, Small Tool Equipment, Inner Tube Repairs, Outer Casing
Repairs

Electrical Equipment for Gasoline Cars ....

By Charles B. Hayward Page 375

Electrical Principles: Electric Circuit: Current. Electrical Pressure,
Resistance, Ohm's Law, Power Unit, Conductors, Voltage Drop, Circuits,
Short-Circuits and Grounds. Size of Conductors, Heating Effect of Cur-
rent, Chemical Effect of Current — Magnetism: Natural and Artificial
Magnets, Poles, Electro-magnets, Magnetic Field, Lines of Force, Sole-
noids — Induction Principles in Generators and Motors: Induction, Self-
induction, Condensers, Pressure and Voltage. Power Comparison, Gen-
erator Principles (Elementary Dynamo. Commutators. Armature Wind-
ings, Field Magnets, Brushes), Electric Motor Principles (Theory of
Operation, Counter E.M.F., Types, Dynamotors, Batteries) — Summary of
Electrical Principles (General, Ohm's Law. Magnetism. Induction, Con-
ductors, High-Tension Currents, Circuits, Hydraulic Analogue, Generator
Principles. Motor Principles, Batteries)

Review Questions . Page 455

Index Page 461

♦For page numbers, see foot of pages.

fFor professional standing of authors, see list of Authors and Collabo-
rators at front of volume

Digitized by

Google

8°.

§1

* t

w i

o v

Digitized by

Google

GASOLINE AUTOMOBILES

PART IV

CLUTCH GROUP

TYPES OF CLUTCHES

Classification. Principal among the indispensable parts inter-
vening between engine and road wheels, and one which may be a
source of great joy or correspondingly great wrath, according to
whether it be well or poorly designed and fitted, is the clutch. There
are six forms into which clutches may be divided, although not all
of them are in general use in the automobile. Only the first four are
widely used on automobiles. These different forms are:

(1) Cone clutches

(2) Contracting-band, or drum, clutches

(3) Expanding-band, ring, clutches

(4) Disc and friction clutches

(5) Hydraulic, or fluid, clutches

(6) Magnetic, or electric, clutches

The necessity for a clutch lies in the fact that the best results
are obtained in an automobile engine when run at constant speed.
In as much as the speed of the car cannot, from the nature of its use,
be constant, it requires some form of speed variator. This is the
usual gear box, or transmission, but, in addition, there is the necessity
of disconnecting it from the motor upon starting, since the engine
cannot start under a load. There is also the necessity for disconnect-
ing the two when it is desired to change from one speed to another
either by way of an increase or a decrease. So, also, when one wishes
to stop the car, there must be some form of disconnection. There
are, then, three real and weighty reasons for having a clutch.

Requirements Applying to All Clutches. In a serviceable clutch
there are two general requirements which are applicable to all forms.
These are gradual engagement and large contact surfaces, although
the latter requirement may be made to lose much of its force by

i j

Google

352

GASOLINE AUTOMOBILES

FACING SPKING

xXBSSn

making the surfaces very efficient. In the cone clutch, gradual
engaging qualities are secured by placing a series of flat springs under
the leather or clutch lining. By means of these springs, acting against
the main clutch spring, the clutch does not grab, since the large
spring must have time in which to overcome the numerous small
springs. In this way, the engagement is gradual and the progress of

the car is easy as well as
continuous.

The specific neces-
sity in a cone clutch,
whether it be direct or
inverted, is a twofold one
— sufficient friction sur-
face and proper angu-
larity. The latter, in a
way, affects the former,
as will be discussed more
in detail later. The an-
gularity varies in practice
from 8 to 18 degrees.

Cone Clutch. The
cone clutch consists of
two members, one fixed
on the flywheel or other
rotating part of the en-
gine and the other fixed
to the transmission shaft.
The latter usually slides
upon the shaft so as to
allow engagement and disengagement. A spring holds the two
together or apart, according to the type of clutch used. When
the smaller-diameter member is spoken of, it is usually called the
male member, while the part of larger size is spoken of as the
female member.

The cone type is made in two different varieties: one in which
the male member enters the female naturally at the open end is
called the direct cone type; in the other, the male member is set within
the structure of the female and is pressed outward toward the open

ENGAGING SPRING

Fig. 246. Section through

Direct Cone Clutch
Courtesy of Studtbaker Corporation, Detroit, Michigan

Digitized by

Google

GASOLINE AUTOMOBILES 353

end to engage it. This is called the inverted, or sometimes the
reversed, cone clutch.

A great disadvantage of the inverted form is that the spring must
be carried between the two cones, which means that it is inside where
it cannot be reached for adjustment. This form causes trouble in
assembling because the male cone must be put in place with the
spring between it and the flywheel before the female can be set into
its place and bolted up. These two big sources of trouble have caused
designers to turn to the direct type more freely, as it lends itself
readily to an external
adjustment. If the spring
is outside, it is easily put
into place and as easily
taken out.

An excellent exam-
ple of the direct cone
clutch is seen in Fig. 24G,
which shows the Stude-
baker clutch in section.
The noticeable point
about this clutch is its
simplicity. It will be
noted that the spring is
entirely enclosed, so that
when it needs adjusting
the repair man must

. . l • • Fig. 247 - Direct Cone Clutch with Cork Iuaerto

open the universal joint

and operate the bolt A which regulates the tension of the spring.

Another good example of the simplicity of the cone clutch is seen
in Fig. 247, which is an aluminum member with bosses cast for cork
inserts. Between the inserts may be seen the flat heads of the copper
rivets which hold the clutch facing in place. Obviously, this has the
same disadvantage of internal, and thus inaccessible, spring.

In the cone type of clutch, shown in Fig. 248, the inaccessible
spring is avoided. In addition, a number of small springs are used in
place of one very large and very stiff one. The ease of adjustment
and the greater ease in handling the springs make this clutch a much
better design for average use from the repair man's point of view.

Google

354

GASOLINE AUTOMOBILES

An example of the inverted-cone type is shown in Fig. 249, which
shows the clutch on the four-cylinder Stearns-Knight. This type has
an odd number of small springs equally spaced around the clutch,
but these cannot be adjusted from the outside.

Contracting-Band Clutch. A short consideration of the band
style of clutch shows that this does not differ radically from the ordi-
nary band brake, either in construction, application, or actual work-
I ing. The difference in the

^- two lies in the fact that the

band, as a clutch, is de-
signed to transmit power
with as little loss as possi-
ble, while the band as a
brake is designed to absorb
the forward energy of a
moving vehicle in the short-
est possible space of time,
i.e., to waste as much power
as possible.

Fig. 250 shows a typical
contracting-band clutch. It
will be noted that this clutch
has the two parts, or sec-
tions, of the band united at
the bottom and two oper-
ating levers pivoted at the
top, where a single conical-
shaped cam moves both
outward and tightens the
bands on the drum.

The usual place in
which the band clutch is
found is in connection with a planetary transmission. There the band
is always used, and there it reaches its simplest form, that of the plain
band wrapped around the drum. One end is fixed and the other
attached to the braking, or more correctly, the clutching, lever. A
plain pull on this effects the clutching action. A more modern and
more efficient form has one end of the band attached to one extremity

Fig. 248. Direct Cone Clutch with Small Springs and
External Adjustment
Courtesy of W iUys-Oterland Company. Toledo, Ohio

Digitized by

Google

GASOLINE AUTOMOBILES

355

of the clutching lever, while the other end of the band is fastened to
the middle of this lever. The clutching pull comes upon the upper
extremity of the lever. Then the band acts to aid in clutching itself,
i.e., a scissors action is obtained, and the required pull is lessened.

This construction can be seen quite plainly in Fig. 287, which
shows the planetary transmission and bands used on Ford cars. In
this, the low- and reverse-speed
bands are shown in full. This
is of particular interest as Mr.
Ford is now the only American
maker using the planetary form
of transmission, all other makers,
even of very low-priced machines
— some below the Ford price —
having gone to the selective
sliding-gear form.

Expanding-Band, or Ring,
Clutch. The expanding-band
clutch finds favor among few.
Like the contracting band, which
is very similar to the band form
of brake, the expanding band is
much like the expanding type of
brake, except that the clutch is
used to form the connection be-
tween two rotating parts. Viewed
from the standpoint of pure
engineering, the expanding band
is little different from the cone
type of clutch, granting that the
angularity of the operating cam
is the same as that of the cone.

Much depends upon how the band is expanded. This expansion
is usually accomplished by means of screws, which may be either
right-handed or left-handed or both.

Another form is expanded by a right-and-left screw operated
by a lever. The lever, in turn, is moved by a pair of sliding collars on
the main-clutch shaft, the clutch foot pedal moving these forward.

Fi K

249. Inverted Cone Clutch Used on
Steams- Knight Four-Cylinder Cars
Courtesy of F. B. Stearns Company,
Cleveland, Ohio

Digitized by

Google

356 GASOLINE AUTOMOBILES

Disc Clutch. With its advent in 1904, the multiple-disc clutch
has steadily grown in popularity, until today it is looked upon as the
most satisfactory solution of the difficult clutch problem. Designers
who have once adopted it, seldom, if ever, go back to another form,
while of the hew cars coming out from time to time nearly three-
fourths are equipped with some form of disc clutch.

Popularity Compared with Other Forms. Statistics for 1914
showed that the disc form of clutch was easily the most popular type.
Of 230 different chassis for 1914, 119 were equipped with disc clutches,
97 with the cone, 9 with a contracting-band type, and but 5 with an
expanding-band form. The relative figures for 1916 were about 94

Fig. 250. Typical Contracting-Band Clutch

disc, 81 cone, no contracting band, no expanding band, and 1 electric.
This would give the first-named approximately 54 per cent of the total.
Two Forms of Same Make. Reference to the types of clutch
brings to mind the relative advantages of the two leaders, the cone
and the disc. These are presented in a very striking manner in
Figs. 251 and 252, which show the cone and disc clutches used inter-
changeably by the Warner Gear Company, Toledo. These clutches
are designed to be interchangeable, consequently the general layout
is the Same. It will be noted that the cone is somewhat simpler than
the disc, as it has fewer parts which take up room. The design is such
that the internal spring of the cone can be adjusted from the outside

Digitized by

Google

GASOLINE AUTOMOBILES 357

as can the outside spring of the disc. An interesting point in this
connection is that the transmissions also are interchangeable, although
the type, Fig. 252, with roller bearings is intended for a moderately
heavy passenger car, while that in Fig. 251 is for lighter work.

Simple Types. The simple types differ in number and shape of
discs, method of clutching, material, and lubrication ; but in principle
all are alike. This clutch is one in which the flat surfaces properly
pressed together will transmit more power with less trouble than any

Fig. 251. Typical Three-Speed Geareet with Cone Clutch for Unit Power Plant
Courtesy of Warner Gear Company, Toledo, Ohio

other form. By multiplying the number of surfaces and making
them infinitely thin, the power transmitted may be increased indefi-
nitely. That this is not idle fancy is shown by a number of very
successful installations of 1000 horsepower and over in marine service.
The minimum number of plates in use is said to be three, but
very often the construction of a three-plate clutch is such that one or
two surfaces of other parts are utilized, making it a two- or even one-
plate clutch in reality. # In the Warner clutch, shown in Fig. 252,
there are really but two clutching surfaces, the face of the inner plate

Digitized by

Google

358 GASOLINE AUTOMOBILES

against the flywheel and the outer face against the engaging disc.
Both plates are faced with suitable friction surface but it really is a
one-disc clutch.

Multiple-Disc Clutches. The modern tendency in disc clutches,
however, is away from those of few plates requiring a very high
spring pressure — since the friction area is necessarily limited —
toward the multiple-disc variety, in which a very large area is
obtained. The large area needs a very light spring pressure, and

Fig. 252. Typical Thrw-Spced Warner Gear Box Shown in Fi«. 251 , but with Disc Clutch

consequently it is easier to engage and disengage the clutch. For this
reason, the multiple disc is becoming more popular with owners and
drivers than the variety requiring the extra-heavy effort. The con-
struction of the three-plate disc clutch does not differ radically from
one maker to another. Three fingers are used to clutch and declutch
generally, the amount of movement being adjustable. A single spring
of large diameter and large-size wire is generally used, and sheet steel
is used for one-half the clutch plates. Between the three-plate and
multiple-disc are many gradations.

Digitized by CjOOQIC

GASOLINE AUTOMOBILES 359

In the true multiple-plate clutch, there are three general varieties
met with in practice: the metal-to-metal with straight faces; the
metal-to-metal with angular or other shaped faces designed to
increase the holding power; and the straight-face kind in which metal
does not contact with metal, one member either being lined with a
removable lining or fitted with cork inserts.

Metal-to-Metal Dry-Disc Type. The metal-to-metal method has
the additional advantage of having the central part within which the
clutch is housed very small in diameter, so that the portion of the fly-
wheel between the rim and the clutch housing may be made in the

Fig. 253. Multiple-Disc Clutch and Transmission of Winton Cars
Courteey of Winton Motor Car Company, Cleveland, Ohio

form of fan spokes that convert it into a fan which serves to cool the
motor better.

As the various examples of disc clutch shown would indicate,
the designer has had his choice between a few large discs and a large
number of small ones. If he chose the former, the clutch could be
housed within the flywheel, but that would make it inaccessible. If he
chose the latter, the clutch could not be kept within the flywheel
length. A separate clutch housing would be a necessity, but the
clutch could be made accessible and flywheel fan blades could be used.

Another example of the plain metal-to-metal disc clutch is shown
in Fig. 253. In this case also the clutch is not housed in the flywheel,

Google

860 GASOLINE AUTOMOBILES

as in most of the preceding examples of this form of clutch, but in the
forward end of the transmission case, that is, instead of motor and
clutch forming a unit, the clutch is a unit with the transmission. It is
claimed that this position makes it more accessible, since it brings the
clutch directly under the floor boards of the driver's compartment
where it can be lubricated better. The lubrication is effected through
communication with the gear part of the case, which is always filled
with lubricant.

In the figure it will be noted that there are 13 driven discs, with
keyways, which hold them to the driven drum. Note that the drum
is held to its shaft by means of a pair of large set screws. The clutch-
ing springs are of small diameter and size, spaced equally around the
periphery of the discs; each disc is enclosed in a small and thin metal
casing. Attention is called also to the universal joint shown. This
joint forms the rear end of the driving connection*with the flywheel,
which will be referred to later. These discs are flat-stamped out of
sheet steel with the proper keyways for internal or external holdings.

Use of Facings. The more modern disc clutch has two sets
of sheet metal discs, one of which is faced on one or both sides with
a special material. Without a single exception, all the disc clutches
shown have had plain discs against plain discs. This makes a simple
and fairly inexpensive construction, but one that is not very efficient.
The most recent tests have shown that metal against metal gives a
coefficient of friction of but .15, which is reduced to .07 when the
surfaces become oily or greasy. With one of these contacting faces
lined with leather, the coefficient rises to .23 when dry and to .15 when
oiled. Again if fiber is used for the facing, the coefficient becomes,
respectively, .27 and .10, while with cork or with cork and leather, it
becomes, respectively, .35 and .32. Here is a very apparent reason
for (1) facing the clutch discs, and (2) running them dry.

By going over these figures, it will be noted that discs with
almost any form of facing will show an increase in efficiency over the
same discs without facing, varying from 60 up to almost 300 per
cent. Again, any form of disc clutch, faced or otherwise, will show
a much higher coefficient when dry than when oiled and thus a
greater efficiency. These two facts point out the obvious reasons
for the modern tendency toward the multiple-disc clutch, faced and
running dry.

GASOLINE AUTOMOBILES 361

To present an example of the faced type, Fig. 254 shows the
multiple-disc clutch of the eight-cylinder V-type Cadillac. In this
illustration the eight driving discs can be seen with the facing on
each side of each one. This facing is of wire-mesh asbestos, and
between each pair of discs comes a plain driven disc, so that it has a
facing of the asbestos against each side of the metal which it grips.
The keys holding the inner discs to the shaft can be seen on the

Fig. 254. 1917 Cadillac Clutch and Transmission, Showing New Clutch Drive
Courtesy of Cadillac Motor Car Company, Detroit, Michigan

end of the housing, while the slots into which the keys project can
be seen on the discs. By examining the group closely, the driven
plain discs can be seen between each pair of the drivers. The
method of driving these discs through a multiplicity of keys and
grooves is unusual, but it is a good example of Cadillac thoroughness.
Fig. 254 also shows the pedals and the exterior of the clutch case
where it bolts up to the engine. This indicates how a unit power
plant simplifies the control group and eliminates parts.

Google

362 GASOLINE AUTOMOBILES

Floating Discs a Novelty, The clutch on Locomobile cars,
shown in section in Fig. 255, is very much like the Cadillac just
shown, except for the novel feature that the fabric facings are not
attached either to the driving or to the driven discs but float between
them. This fabric, usually a woven asbestos material with a central
core of interwoven metal wires, instead of being attached to both
sides of every other disc or to one side of every disc, is not attached
at all. The rings for the fabric discs are made up in the form of
annular rings. They have the same inner diameter as the inside of the

Fig. 2">5. Floating Dry-Disc Clutch Used on Locomobile Care

driving discs and the same outside size as the driven discs; conse-
quently, assembling one of these clutches is simply a question of
piling first a driven disc, then a fabric, then a driving disc, and so on.

The fact that the fabric rings are not united to either of the
metal discs allows them to free themselves with remarkable rapidity
so that either on engagement or on declutching the action is very quick .

Greater Power Transmitted by Surfaces Not Plane. To increase
the power transmitted by a clutch of given size, either the number of
plates must be increased or the form of the surface changed. The
latter method was followed on the clutch of the French car "Ours."

GASOLINE AUTOMOBILES

363

The discs of this unusual clutch had a perfectly flat outer portion
and a conical inner portion, only the latter taking part in the trans-
mission of power. In this disc form, then, we have the advantage
of the disc economy of space, together with the advantages of the
cone clutch and the additive gain of running in a bath of oil.

Another form utilizing this principle, and one that is more widely
used, is that known as the "Hele-Shaw" so named from its inventor,
the famous English scientist, Dr. H. S. Hele-Shaw. This is essen-
tially a flat disc, as shown at A, Fig. 256, with a ridge B at about
the middle of the friction surface; this ridge consists of a portion

Fig. 256. Hele-Shaw Disc Clutch, Showing Cone Surfaces

of the surface, which has been obtruded during the stamping process
in such a way as to leave the surface of the ridge in the form of an
angle of small height. The angle used is 35 degrees, and this value has
been determined upon experimentally as the best. Fig. 256 shows a
cross-section through an assembled clutch, which reveals the clutch
angle very plainly. In use, the ridges nest one on top of the other;
and in the extreme act of clutching, not only the flat surfaces but
both sides of the ridge are in contact with the next plate. Thus, not
only is the surface for a given diameter increased, but the wedge
shape is also taken advantage of.

Digitized by

Google

364 GASOLINE AUTOMOBILES

Hydraulic Clutches. All the methods of engaging and dis-
engaging the engine at will, as discussed before, have been of a
mechanical nature. The hydraulic clutch, on the other hand, par-
takes more of the fluid nature, although it is operated by mechanical
means. Ordinarily, it is in the nature of a pump with a by-pass,
the pump working at ordinary speeds to force the heavy liquid,
usually glycerine, through the by-pass. To clutch up tightly, how-
ever, the by-pass is closed and, the liquid being unable to circulate
while the pump continues to operate, the whole device is rotated as
a unit. In this case it operates just as any other clutch, but, due to
the sluggish action of the fluid, it is slower to respond. Then, too,
the grave question of leakage is always present, and the smallest leak
puts the clutch entirely out of use. These disadvantages, together
with the necessary complications, have retarded the development of
the hydraulic form so that there are few of that type in use today.

Magnetic Clutch. All the foregoing clutches present in one
form or another very complicated devices for freeing the transmission
shaft from the engine shaft, but the magnetic clutch is a device which
has simplicity for its foremost argument. The magnetic clutch
consists primarily of three parts: the field, usually in the form of a
ring; the armature, always of ring shape; and the oil casing shaped
to accommodate the other parts, its function being that of a cover.
The armature is a simple cast-iron plate of rectangular section,
adapted to be drawn into engagement with the field when the latter
is energized.

The field, on the other hand, is made up of the back plate,
the inner and outer field rings, the magnetizing coil, and the contact
rings. In operation, the accelerator is energized by closing the
electrical circuit, which sends a current through the field. This
magnetism attracts the armature, which then moves laterally, clos-
ing the very small gap between the two. The oil in which the
whole clutch works prevents it from taking hold suddenly, or grip-
ping, but as this oil film on the two surfaces is gradually squeezed
out, the clutch as gradually takes hold.

New Electric Generating Clutch. So great has been the interest
in the various electrical mechanisms in the automobile, and so
quickly has the public taken up with all these that this has stimu-
lated an entirely new invention, called by its maker, the Vesta

Digitized by

Google

GASOLINE AUTOMOBILES 365

Accumulator Company, Chicago, a centrifugal electric-generating
clutch. This name gives a little clue to its action, which is that of a
combination of the usual friction clutch and that of the electric-
magnetic drag between armature and fields of any electric machine.
In addition to its clutching feature, its ability to drive when
partially clutched makes it, in effect, a transmission, so that it is
designed to replace the usual clutch, gearset, flywheel, electric gen-
erator, and starting motor. It is composed of two parts: an arma-
ture, which becomes the flywheel; and a field mounted on the pro-
peller shaft. The former carries an internal commutator, and the

Fig. 257. Field Unit of the Vesta Centrifugal Electric Clutch
Courtesy of Vesta Accumulator Company, Chicago, Illinois

latter carries brush holders which hold brushes against the commutator.
These brushes are mounted so that the centrifugal force of rotation
increases the force with which they press against the commutator.
Thus there is a variation from practically no contact up to the maxi-
mum, at which point the centrifugal force is so great that field and
armature revolve as a solid unit.

This construction is well indicated in the two illustrations of this
device, Figs. 257 and 258. Fig. 257 shows the field unit mounted on
the propeller shaft in which F is one of six field poles, B a brush, and
C one of the collector rings. Fig. 258 is an external view which shows

Digitized by

Google

366 GASOLINE AUTOMOBILES

the clutch assembled. In this illustration the brushes B are shown
pressed out against the commutator by the centrifugal force.

An automobile built in France — the Ampere — uses the electric-
generating clutch construction exclusively, the master clutch being
dispensed with in favor of an individual-clutch transmission. The
differential is dispensed with, and in its place a pair of magnetic
clutches — one for each wheel — are used. The differential action is

Fig. 258. Assembled Vesta Electric Clutch
Courtesy of Vesta Accumulator Company, Chicago, Illinois

obtained on curves by decreasing the current to the clutch on the
inner wheel up to a certain point, at which it is cut off entirely. This
gradual reduction and cutting off of the current is accomplished
automatically by the movement of the steering wheel.

DETAILS OF CLUTCH OPERATION

Methods of Operation. Practically all modern clutches are
operated by means of a special pedal moved by the left foot. The
pedal is connected to the internal member by means of rods and levers,

Digitized by

Google

GASOLINE AUTOMOBILES

367

which compresses the clutch Spring or springs and allows the clutch
members to separate. This throws the clutch out. To throw it
back in, remove the foot pressure from the pedal, and the springs
again exert pressure and force the parts together. This action
causes them to take hold. There was a time when a considerable
number of cars had the clutch so constructed that the pedal held it
in and the springs threw it out, just the reverse of the present plan.
This method is no longer used, as it necessitated a constant pressure
on the pedal while driving — a very fatiguing process.

Gradual Clutch Release. The Dorris clutch, made by the Dorris
Motor Car Company, St. Louis, Missouri, Fig. 259, is a new arrange-
ment of the clutch pedal,
and its operation is such
that the clutch is released
or thrown out with very
light pressure on the
pedal. Pressure "on the
pedal A is transmitted
by the shorter lever arm
B, thus greatly increas-
ing the leverage. This
pressure is transmitted to
lever C and through it to
lever D, these two being
hung on the frame cross
member E. As C is much
longer than D, there is
another multiplying ac-
tion here. This does not
act directly upon the
clutch but upon the upper
end of the clutch shifter
F, which is attached to the clutch at G and pivoted at its lower
end H — here again in a multiplying action. The net result of these
three multiplications is a combination which will release the strongest
and stiffest clutch with a very slight pressure of the foot.

Clutch Pedals. It has been the general practice in the past to
have the clutch pedals separate and distinct, with the service-brake

Fig. 259. Multiplying Lever of Dorria Clutch to

Make Pedal Pressure Light

Courtesy of Dorris Motor Car Company, St. Louis, Missouri

Digitized by

Google

368 GASOLINE AUTOMOBILES

pedal on a concentric shaft occasionally. Now, however, the rapidly
growing practice of simplification and elimination, combined with the
wide use of the unit power plant, is eliminating the so-called clutch
shaft with its bearings and fastenings to the frame, to the clutch
operating yoke, and to many other parts. As the Cadillac illustra-
tion, Fig. 254, shows and as the Buick drawing, Fig. 260, shows even
better, all these shafts, rods, and fastenings can be eliminated and the
pedals and levers mounted directly on or in the power unit. In the
Buick illustration, the foot brake has a simple rod connection from
the ear A on the pedal to the brake-operating system, while the

Fig. 260. Unit Power Plant of New Small Buick Four
Courtesy of Buick Motor Company, Flint, Michigan

hand brake has a similar connection from the extended lower end of
the rod B to that brake-operating system. In this simple way,
perhaps 40 or more pieces are eliminated and their weight saved.
Clutch Lubrication. As has been previously pointed out, some
clutches run in oil, while others run dry. The former type must be
kept filled with lubricant at all times. The general plan in such a case
is to provide a lead from the engine oiler when the clutch case is
separated from the engine case or a connecting means when the two
are in one case. In addition to the actual clutching members, there
is practically always a sliding member, which must have lubricant of
some form, while the thrust bearings to take the thrust of the clutch

Digitized by

Google

GASOLINE AUTOMOBILES 369

springs must be cared for. Generally, these two cases are cared for
by a pair of grease cups, which are visible in Figs. 247 and 249.
The operating rods are lubricated usually by means of small oil holes,
either drilled directly into the part or covered with a small oil cup.
In those cases in which the clutch runs in oil, it will be noted that a
filling plug is provided, by means of which additional lubricant can
be poured into the casing, Fig. 256.

Clutch-bearing lubrication is highly important, particularly with
clutches like the cone which must be kept free from lubricant and the
dry disc in which lubricant is not used. Where the clutch itself
runs in oil, it is a simple matter to lubricate the bearings, but in
the other cases, oil or grease must be provided from one of three
places: from a prolongation of the engine oiling system, as shown in
Figs. 246 and 251; from the outside — generally by means of grease
cups — as just discussed; or from the transmission end. The last
form is used only in unit power plants; combinations of clutch and
transmission, as shown in Fig. 253; and in cases, Fig. 256, where
the construction allows a grease or an oil cup attachment at the
transmission end, the transmission itself being some distance away.
. Clutch Bearings. The need for bearings in a clutch depends
somewhat upon its nature and location, but regardless of these a
thrust bearing is needed for the clutch spring. To explain this
briefly, it is known that action and reaction are equal, and opposite
in direction. For this reason, when a clutch spring presses the discs
or parts together with a force of, sav, 100 pounds, there is exerted
in the opposite direction this same force of 100 pounds. In order to
have something for this to work against, a bearing is used, and since
it takes up this spring thrust, it is called a thrust bearing. Not all
bearings are fitted to take thrust, as the majority are designed for
radial loads only. For this reason a special design is needed.

When the clutch is incorporated in the flywheel, two additional
bearings — one for the end of the crankshaft and another for the
transmission or driven shaft — are generally needed. The bearings
will be noted in Figs. 246, 248, and 249, although the transmission-
shaft bearing does not have the clutch combined with the engine but
rather with the transmission. In the majority of cases, it will be
found that a means of fastening the end of one shaft has been worked
out so as to eliminate one bearing. This accounts for the large

Digitized by

Google

370 GASOLINE AUTOMOBILES

number which show but two — the thrust and one other. In looking
back over the clutches, it will be noticed also that nearly all the bear-
ings are of the plain ball form. This is due in large part to the fact
that the plain ball bearings take up the least room for the load carried,
both in diameter and width — a contributing reason being the fact
that in many cases one of the shafts or parts can be formed to take
the place of either the inner or outer ball race.

Clutch Adjustment. Adjusting a clutch, as a rule, is not a
difficult task as there are but two possible sources of adjustment — the
throw or movement of the operating pedal or lever and the tension
of the spring. An adjustment is generally provided for each. When
the fullest possible throw of the pedal does not disengage the clutch,
an adjustment is required to give a greater throw. If the throw is
correct, but the clutch takes hold too quickly and vigorously, the
spring pressure can be lessened somewhat to soften down this action.
On the other hand, when dropped in quickly, if it takes hold slowly,
more spring pressure is needed, and it should be tightened.

Clutch Accessibility. Clutches are made accessible in two ways:
by their location on the car and by the relative ease with which they
can be removed. Accessibility as to location is less in the various
combinations, such as in the unit power plant, housed within the
flywheel, or combined with the transmission. Ease of removal is
determined by the number and location of the joints (usually uni-
versal) used with the clutch.

CLUTCH TROUBLES AND REMEDIES

The very fact that the clutch is a more or less flexible, or rather,
variable, connection between engine and road wheels makes it
necessary that it be kept in the best of shape. It is rather surprising
to the novice with his* first clutch trouble to have his motor racing
at the highest possible speed and to find his car barely moving, but
to the experienced driver it is humiliating.

Slipping Clutch. Slipping is the most common of clutch trou-
bles. This is brought about in a cone clutch by oil, grease, or other
slippery matter on the surface of the clutch and can often be cured
temporarily by throwing sand, dirt, or other matter on the clutch
surface, although this is not recommended. Many times, the
clutch leather, or facing, becomes so glazed that it slips without any

Digitized by

Google

GASOLINE AUTOMOBILES 371

oil or grease on it. In that case it is desirable to roughen the surface.
This may be done by taking the clutch out, cleaning the surface with
kerosene and gasoline, and then roughing-up the surface with a file
or other similar tool.

In case it is not desired to take the clutch out, or when it is very
inaccessible, the clutch surface may be roughened by fastening the
clutch pedal in its extreme out position with some kind of a stick,
cord, or wire, and then roughing the surface, as far in as it can be
reached, with the end of a small saw, preferably of the keyhole type,
as shown in Fig. 261. Before starting this repair, it is well to soak
the leather with neat's-foot oil. This softens the leather and makes
the roughening task lighter.

Many drivers make the mis-
take of driving with the foot
constantly on the clutch pedal.
This wears the leather surface
and helps it to glaze quickly.
The constant rubbing from fre-
quent slipping makes the leather
hard and dry.

When a metal-to-metal oiled
clutch slips, the trouble usually is
in the clutch spring, which is too

weak to hold the plates together. $ To remedy slipping with this
type, it is necessary to tighten up the clutch-spring adjustment.

Clutch troubles are not always so obvious. In one instance,
the clutch slipped on a new car. In the shop, the clutch spider
seemed perfect and properly adjusted, also the spring, but to make
sure, a new clutch was put in. Still the clutch slipped. To test it
out still farther, the linkage was disconnected right at the clutch
and then it held perfectly, showing that the trouble was in the link-
age. On examination one bushing was found to be such a tight fit
that it would not allow the pedal to move freely enough to release the
clutch fully. When this was relieved a little, the clutch acted all right.

Replacing Clutch Leathers. Clutches offer many chances for
trouble. The most frequent causes are the wear of leather facings
with the attendant loss of power, and weak springs. Weak springs
may be cured by screwing up on the adjusting nut or bolt provided.

Google

372

GASOLINE AUTOMOBILES

Slippery leather may also be corrected by washing first with gaso-
line and then with water, finally roughing the surface with a coarse
rasp and replacing only after the leather is thoroughly clean. Dry
leather is fixed by soaking in water or neat's-foot oil. It should be
replaced while still moist, and copious lubrication will keep it soft.
The greatest problem in replacing a worn, charred, or otherwise
defective leather lies in getting the right layout for the form of the
new leather the first time. It must be remembered that the surface
is a portion of a cone and, therefore, its development is not easy.

It is attacked in this man-
ner: Prepare the cone by
removing the old leather
and all rivets, cleaning out
the rivet holes, and provid-
ing new rivets. Measure the
cone, taking the diameters
at both the large and small
ends and also the width.
Take a large sheet of paper
and lay off upon it a figure
similar to A BCD, Fig. 262,
drawn to exact scale and
having for its dimensions
the three measurements
just obtained, viz, the large
and small diameters and the
width of the cone. This
figure represents the projec-
tion of the cone in a flat
plane. Bisect the line AD
and draw the center line EF at right angles to AD. Prolong the
two tapered lines A B and DC until they meet the center line as at G.
The point G represents the apex of the cone if it were complete,
and hence any circular arc with the correct radius, drawn from this
point as a center, will be a correct projection of the development
of that portion of the conical surface. With GA and GB as
radii, draw the two circular arcs HAD J and IBCK, also draw the
radial lines /// and JK to pass through G. The enclosed figure

Fig. 262.

Diagram Showing How to Cut Clutch
Leathers

Digitized by

Google

GASOLINE AUTOMOBILES 373

HIBCKJDAH may then be cut out and used as a pattern from
which to cut out clutch leathers. If the distances AH and DJ be
made approximately equal to or slightly more than AD y the pattern
will a little more than encircle the cone clutch.

After the leather has been cut out, it should be prepared by
soaking in water or oil, according as its surface is fairly soft or rather
harsh. In either case, it must be well soaked, so as to stretch easily.
In putting it on the cone, one end is cut to a diagonal, laid down on
the cone, and riveted in place. Next, the leather is drawn down
tightly past the next pair of rivet holes, which are then driven into
place. This is continued until the strip is secured. The leather is
now wetted again, for, if allowed to dry off immediately, the shrinking
action will break it out at most of the rivet holes and render it use-
less. By drying it out gradually, a taut condi-
tion may be arrived at without this danger.

Handling Clutch Springs. Clutch springs,
like the valve springs mentioned previously,
are mean to handle and compress. The best
way is to compress and hold them compressed
until needed. For this purpose, a rig similar
to that described for valve springs should be
made but of stifFer stronger stock. A very
good one can be made from two round plates,
one small, and the other of larger diameter with
a pair of L-shaped bolts through it. The

\ ^ & Courtesy of "Motor World"

spring is placed between the two, with the
ends of the L's looped over the smaller plate, and then, by tight-
ening the nuts on the bolts, the spring is gradually compressed.
An excellent device for holding clutch springs consists of a
simple pair of metal clamps which are joined together by three or
more short metal bars, as Fig. 263 shows. If one particular clutch
spring is handled continuously, the length can be made to fit this
best, otherwise it will have to be made of any convenient length.
The inside diameter of the clamps when fully open is greater than
the outside diameter of the spring. The clamp is set in a vise or on
a drill press and the spring set inside of it. Then the spring is com-
pressed by working the vise handle or by lowering the drill-press
spindle. When compressed down to the length used in the car, the

Google

374

GASOLINE AUTOMOBILES

ends of the clamp are tightened and the spring is held by friction.
Then the spring can be handled readily, using one of the metal bars
as a handle. It is put into place, and then the retaining screws can
be loosened and the clamp removed.

Fierce Clutch. A fierce clutch is one that does not take
hold gradually but grabs the moment the clutch pedal is released.
In a metal-disc clutch, this is caused by roughened plate surfaces
and insufficient lubricant, so that, instead of the plates twisting
gradually across each other as the lubricant is squeezed out from
between them, they catch at once and the car starts with a jerk.
On a cone clutch, this fierceness is produced by too strong a spring,

too large a clutching sur-
face in combination with a
very strong spring, or a hard
or burned clutch surface or
both.

Ford Clutch Troubles.
There are now so many
Fords in use that the aver-
age repair man feels justified
in making special apparatus
or tools to save time or
work in Ford repairs. For
one thing, the clutch-disc
drum frequently needs
removal and this is a diffi-
cult job. By means of a simple rigging, however, consisting of a plate
and a few bolts, it can be taken off in a few moments and with little
trouble. It will be noted from Fig. 264 that the rigging is but a modi-
fied form of wheel puller. It consists of a J-inch plate of steel with
three holes drilled in it for three bolts. The two outside ones have
T-head ends and have to be specially made, and made carefully,
as this T-head must slip through either one of the oval holes in
the web of the drum. When this is done, it is straightened up so
as to stand at right angles to the drum and is thus in a position
to press firmly against the drum from the inside. There are nuts
on the center bolt on both sides of the plate, but the drawing shows
only that on the outer end. When the T-bolts are in place, the

Fig. 264. Simple Rigging for Removing Ford
Clutch Disc

Digitized by

Google

GASOLINE AUTOMOBILES

375

center bolt, which is slightly pojnted and preferably hardened on
the end, is screwed down so as to come into contact with the end
of the clutch shaft. # After tightening the center bolt, the T-head
bolts are tightened until they pull 4he drum off the shaft.

Clutch Spinning. A trouble which is bothersome but not
dangerous is clutch spinning. This is the name applied to the
action of the male clutch member when it continues to rotate, or
spin, after the clutch spring pressure has been released. With the
male member connected up to the principal transmission shaft and
gear, as is often the case, these members continue to rotate with it.
This gives trouble mainly in gear shifting, for the member which is
out of engagement is considered to be at rest or rapidly approaching
that condition. When at rest, it is an easy matter to mesh another
gear with this one; but when this one is rotating or spinning, it is
not so easy, particularly for the novice.

Fig. 265. Simple Device for Inserting Corks in Clutches

Clutch spinning may be caused (1) by a defect in the design,
in which case little can be done with it; (2) by a defect in construc-
tion, as in balancing, for instance, which can be corrected; or (3)
it may be due to external causes, as, for instance, in a bearing which
has seized, owing to a lack of lubricant, etc.

In any case, the best and quickest remedy is a form of clutch
spinning brake. This may consist simply of a small pad of leather
or of metal covered with leather so located on the frame members
that the male drum touches against it when fully released. Or it
may be something more elaborate as to size or construction or both.
On many modern cars, in fact on practically all good cars, some form
of clutch spinning brake is fitted. Thus, the Hele-Shaw design pro-
vides at the left end, Fig. 256, a metal cone of small diameter, w T hile
Fig. 255 shows flat concentric discs 19 of the Locomobile clutch.

Cork Inserts. When cork inserts are used in a clutch, the
insertion of new corks is not an easy job. A cork is a difficult and
unhandy thing to work with, and above all to hold straight and true

Digitized by

Google

376

GASOLINE AUTOMOBILES

while applying longitudinal force to it. By making up a special
tool with a tubular member having an inner taper, into which the
corks are forced by means of a special plunger which forms the other
part of the tool, this is simplified* considerably. This tool is shown
in Fig. 265, with such dimensions as would be needed for a J-inch
cork. It is advisable to make the small end of the tube J inch smaller
than the cork, as this amount provides the proper compression.
After being soaked in water for 10 or 15 minutes, the cork is dropped
into the large end of the tube, and, with the small end in place

against the cork opening in the
clutch, a single stroke of the plunger
will force the cork through the tool,
incidentally compressing it into the
hole in the clutch. With a few
handlings any clever mechanic can
soon become expert in the use of
this tool.

A more elaborate device, but
one which works more quickly where
there is a great deal of this work, is
shown in Fig. 266. This is not an
expensive machine — the original of
this sketch was home made. The
framework is made of standard pipe
fittings, the spring is a valve spring,
and the rods are cold rolled steel.
Only a few pieces such as the working
member C were specially made. The
working member is made with a slot
at A into which the corks are inserted.
When the pedal attached to the rod D is pressed, it brings the rod
down and forces out the cork at B. At point B, the clutch resting
on the anvil E is held ready. The stop limits the downward move-
ment, so a strong stroke of the foot will just push the cork into the
hole flush and no more. The lower end of the working member is
made with a taper so as to compress the corks about J inch, as men-
tioned before. They should be soaked in water just the same as
when using the hand tool.

Fig. 266.

Machine for Handling Cork
Inserts Quickly
Courtesy of "Motor World"

Digitized by

Google

GASOLINE AUTOMOBILES 377

In Fig. 267, several other common clutch troubles and their
remedies are suggested; the parts shown in the illustration, however,
are in excellent condition, in fact, new.

When the right kind of clutch discs for a multiple-disc form are
not on hand, new discs can be cut from leather to answer the purpose
by means of the gasket cutter, shown in Fig. 268. This cutter con-
sists of a pair of steel L-shaped arms, preferably forged, with points
sharpened enough to cut the leather or the gasket material. The
clamp has a point for the center of the circle on its under side, while

liwraal

► joint
rue

Fig. 267. Clutch Troubles Illustrated

the actual clamping is done by the bolt or screw with wing head.
To use for clutch discs, set the inner, or shorter, member to the radius
of the inside of the outer discs and the outer, or longer, arm to the
radius of the outside of the inner discs. By pressing down hard on
the arms and rotating them at the same time, an annular ring will
be cut out which will fit exactly. One hand should be held on or
near the center, while the other hand supplies the pressure and
rotating motion on the cutting ends. It should not be expected that
the points will cut through in one revolution; on the contrary, the
first time around will just mark out the section and it will need from

Digitized by

Google

378

GASOLINE AUTOMOBILES

6 to 10 revolutions, with heavy pressure, to cut a leather disc. In
time, the workman will become skilled in the use of this cutter and

Fig. 268. Method of Cutting Facing for Di»c Clutches in an Emergency
Courtesy of "Motor World"

have a knowledge of its limits, as well as of the method of keeping it
in good cutting order.

Adjusting Clutch Pedals. Some cars are made with adjustable
clutch pedals so the long- or short-legged driver can set the length of
these to suit, but when no adjustment is provided and it is desired
to change the length, some figuring must be done. To shorten a
non-adjustable pedal, the best way is to take it out of the car and

bend it somewhat on the order

of the dotted lines in Fig. 269.

The idea is to make the same

amount of metal take a

roundabout and longer path.

In doing this, the workman

must be governed largely by

what the floor boards and the

other parts of the mechanism

in the immediate vicinity will

allow. The bend must be

made so as to allow the pedal

to work in the same slot. If

necessary, cut the slot a

little longer, but first consider the result before bending the pedal.

On the other hand, when the pedal is too short, the pad can be

removed from where it is bolted on at A and a pair of steel strips

cut so as to fit into the two sides of the pedal shank and brought

Fig. 269.

Clutch Pedals to Fit Driver

ing <
Dri

Digitized by

Google

GASOLINE AUTOMOBILES 379

together at the other end. These are bolted in at A, where the pad
was formerly, and the pad moved out to the new end at B. In some
such cases, where the sides of the pedal shank offer no groove to help
hold the steel strips, it is necessary to put another bolt through them,
as at C, to prevent the whole addition swinging about A as a center.

Clutch Troubles Outside of Clutch. Frequently, there is trouble
in the clutch when the basic reason for it is outside of the clutch
entirely. Thus, failure of a clutch to engage or disengage properly
is often the fault of the connecting rods and levers; wear in the clutch
collar or in other parts; or the emergency-brake interlock may have
been fitted so close that as soon as the rods are shortened once or
twice to compensate for wear, it stands in such a position as to throw
the clutch out slightly although the latter appears to be fully engaged.

Another clutch trouble outside of the clutch is apparent slipping
at corners, especially at turns on grades. On a turn — the road being
cambered — the frame is distorted, especially with the combination of
curve and grade. This may be sufficient to throw the clutch and
driving shaft out of alignment just enough so the clutch face will not
make full contact. This is most noticeable on cars with a single
universal joint, in which case the distortion of the frame has more
effect on the driving shaft. Similarly, a car with an unusually light
or flexible frame will show this trouble very often, as the combination
of curve and grade is too much for the light frame.

Summary of Clutch Troubles

Throwing in Clutch. Do not throw clutch in suddenly and cause
rear wheels to spin. Such action is destructive to tires and throws
great stress on the entire mechanism of the car.

Lubricating Multiple-Disc Clutches. These are best lubricated
by injecting oil into the opening for that purpose by means of an oil
gun. A very light lubricating oil should be used.

Multiple-Disc Clutches Failing to Hold. Inject three or four
gunfuls of kerosene into the clutch housing and run the engine a
little, thereby washing out the plates of the clutch. This will cut
the gum caused by the oil. If, after this treatment, the clutch
squeaks or takes hold too suddenly, lubricating oil may be added.

Loss of Power. This is noticeable in changing from intermediate
to high gear, in climbing hills, or in running through muddy or sandy

3g Digitized by VjOOQIC

380 GASOLINE AUTOMOBILES

roads. The trouble is often the result of the clutch slipping. The
remedy is to clean the clutch with gasoline and, if the clutch is leather-
faced, to apply castor oil after cleaning. Castor oil should never be
used on the multiple-disc clutch.

Failure of Clutch to Take Hold. This may be owing to a broken
or weakened clutch spring, the clutch leather may be damaged,
clutch shaft may be out of line or bent, leather may be gummed,
or bearing may be seizing.

TRANSMISSION GROUP

Primarily, the clutch is used to allow the use of change-speed
gearing; or, stated in the reverse way, the form of the transmission
determines whether a clutch must be used or not, there being cases in
which it is not used. Thus, where the frictional form of transmission
is used, no clutch is necessary; the frictional discs act as a clutch
and render another one superfluous. So, too, with the form of trans-
mission known as the planetary gear, no master clutch is needed.

On the other hand, the reverse of this does not always hold. Any
form of clutch may be used with the various other forms of transmis-
sion, as the sliding gear; in fact, in actual practice every known kind
of a clutch will be found coupled with the sliding-gear transmission.

Classification. Broadly considered, there are five classes of
transmissions used. In cases where the use of any one of these
forms eliminates the final drive, this from its very nature does not
alter the facts but simply calls for a different and more detailed
treatment. The five classes are:

/t\ orj* / Operated in various ways

I but usually selective

(2) Individual clutch

(3) Planetary, or epicyclic

(4) Friction disc (various arrangements)

(5) Miscellaneous

The features of the 1917 transmissions which stand out from
previous years are: reduced sizes; simpler, lighter construction;
greater compactness and greater accessibility. Perhaps the most
noticeable trend has been toward the unit power plant which has
helped materially to make transmissions smaller, lighter in weight,
and more simple, with unusual compactness. This very compact-

GASOLINE AUTOMOBILES 381

ness has brought with it a stiffness which has rendered less repairs
and adjustments necessary, despite lighter weight. The smaller sizes
have brought about the simplification and lighter weight, and in
turn have been produced in answer to the popular demand for lighter
weight cars. In part, simplification has been produced by unit
power plants, now so popular.

SLIDING GEARS

General Method of Operation. Of the different types of sliding
gears, the first two subdivisions are not very closely marked, but
blend somewhat into one another. The only real difference between
them is the method of operation, the names serving to indicate the
distinctive characteristics. Thus, in a selective gearset, it is possible
to "select" any one speed and change directly into it without going
through any other. So, too, in the progressive form of transmission,
the act of changing gears is a "progressive" one, from the lowest up
to the highest, and vice versa.

Selective Type. With the selective method of changing gears,
it is possible to make the change at once from any particular gear
to the desired gear without passing through any other. Of course,
the car will not start on the high gear any more than in the other
case, but shifting into low for starting purposes is but a single action,
accomplished quicker than it can be told. So, too, when the car has
been started, it can be allowed to attain quite a fair speed and the
change to high made at once without going through the intermediate
gears.

Progressive Type. Progressive gears, which are now little used,
operate progressively: from first, or low, to second and from second
to third, or high; in slowing down, from third to second to first
and in this way only. This leads to a number of troublesome
occurrences; thus, in stopping, it is necessary to gear down through
all the higher speeds into low. If this is not done, when it is next
desired to start the car, it will be necessary to start the engine, throw
in the clutch, drop from the gear in mesh to the next lower, from that
to the next, and so on down to low, throwing the clutch out and in
for each change of speed. When first is reached, the car may be
started. After starting, it is then necessary, in order to obtain any
measurable speed with the car, to change back up the list, from low

41 Digitized by CjOOQI.C '

382 GASOLINE AUTOMOBILES

to second, from second to third, and so forth. In this way the pro-
gressive gear is disadvantageous, since its use means much gear
shifting; but, on the other hand, the shifting is very easy for the
novice to learn, as it is a continuous process, all in one direction.
Modern Selective Types. To present some modern selective
types of gear boxes and point out their various differences, advan-
tages, and disadvantages, refer to Fig. 270. This type shows the
three-speed selective gear used on the Cadillac cars, which is but
slightly modified from the type which has been used by this concern
for three years. This change should be noted, however; the lay-

Fig. 270. Cadillac Transmission and Housing

shaft, which formerly was on the same horizontal level as the main
shaft, is now placed directly below it. This makes a higher but
narrower gear box, that is, instead of being wide and fairly flat, it
is now high and narrow. The placing of the shifting levers on the
cover, directly over the center, has aided in making the gearset more
compact than formerly. In it there are two shifting gears, one gear
carrying a set of dogs cut into its face, which mesh with a similar set
on the main driving gear to give the direct drive. The gear portion
of this member meshes with another gear for second. The second
shifting member meshes with one gear on the layshaft for low speed

Google

GASOLINE AUTOMOBILES 383

and with another on the third shaft for reverse. The reverse gear
is at all times in mesh with the fourth layshaft gear, so that on
reverse the drive is through five gears instead of four. On high gear
the drive is through the dogs, the layshaft being driven, of course,
but silently, as it transmits no power.

Four-Speed Type with Direct Drive on High. One of the tend-
encies of recent years has been the gradual change toward more
speeds, as shown by the increasing use of four-speed gear boxes.

Fig. 271. Sectional Plan Drawing of the Locomobile Four-Speed Transmission
Courtesy of Locomobile Company of America, Bridgeport, Connecticut

Other indications of this change have been the two-speed axle, which
gave double the number of gear-box speeds, with the ordinary three-
speed and reverse transmission ; and the electric transmission, which
affords seven forward and two reverse speeds.

Following this increase of speeds, the multi-cylinder motors and
downward price revisions of the early part of 1916 brought about a
combination which almost eliminated the four-speed gear box or at
least removed it from aJl but the most expensive of cars and from

Digitized by

Google

384 GASOLINE AUTOMOBILES

many of those. It is claimed that the eight- and twelve-cylinder
motors have so much power and flexibility that a fourth speed is
rendered unnecessary. The four-speed gear box is more expensive
than the three-speed box, and the lowered prices of cars have been
instrumental in preventing its continued use. At the same time,
there was considerable lightening of weight all over the chassis, and
the four-speed gear box had to go out of all but the biggest cars on
account of its greater weight.

Fig. 271 is a sectional plan of one of the few four-speed gear
boxes left. In this drawing it will be noted that the two-gear shafts,
as well as the operating shafts, lie in the same horizontal plane. The
halftone reproduction of the photograph of this drawing, Fig. 272,

Fig. 272. Photographic Reproduction of Locomobile Gear Box Shown
in Section in Fig. 271

shows the location of the shafts even more plainly and will, perhaps,
be of more use to the average reader. Both forms show the arms
which project up to attach this unit to the frame. The cover, which
is a light easily removed aluminum member, is taken off from above
after the floor boards are lifted out. This arrangement makes for acces-
sibility and eliminates any need for lying on the ground while working
on the transmission gears or shafts, should such work be necessary.
The form of final drive alters the construction of the trans-
mission very materially. Formerly, when all final drives were of the
double-chain form, it was customary to include the differential,
bevel gears, and driving shafts in the gear box. Now that the chain
has gone out, this construction is found only when the gear box is a
unit with the rear axle.

Digitized by

Google

GASOLINE AUTOMOBILES 385

Four-Speed Type with Direct Drive on Third. In all the trans-
missions shown and described thus far, the direct drive has been
the highest speed. By referring back to Fig. 253, which show the
Winton four-speed gear box, as well as the clutch, a point of difference
will be seen. This has the direct drive on third speed, fourth being a
geared-up speed for use only in emergencies, when the very highest
rate of travel is required, and when a little noise more or less would
make no difference. This arrangement of the direct drive and silent
speed has long been a debated point, some designers favoring the
direct-drive type with an over-geared speed for occasional use, while
the opponents of this method say that this construction practically
reduces the transmission to a three-speed basis, the fourth being so
seldom used that it is practically negligible. They say, also, that the
modern motor can attain a high enough speed, on the one hand, and is
flexible enough, on the other, to permit its being used with the high-
gear direct drive upon almost all occasions.

Transmission Location. There are but four recognized positions
for the transmission in the modern car. These are: (1) unit with the
engine (unit power plant), (2) amidships in unit with clutch or alone
in a forward position, (3) amidships in unit with forward end driving
shaft or in a rear position, and (4) at the rear in unit with rear axle.

Unit with Engine. The unit wjth the engine type is illustrated in
an excellent manner in Fig. 273, which shows the eight-cylinder
Northway motor, cone clutch, and three-speed transmission. Some
idea of the compactness of this outfit, which is shown exactly as used on
the Oakland car, can be gained from comparison with cylinder bore
and crankshaft size, the motor being 3£ by 4 \ inches. The notice-
able features of the transmission, aside from its compactness, are the
use of double row ball bearings on the splined main shaft, with a
Hyatt roller form for the spigot bearing (free end of main shaft) and
very long plain bronze bushing for the countershaft unit, the latter
being made as a single piece rotating on a single bearing around a
straight fixed shaft. The countershaft, or layshaft, as it is some-
times called, is placed below the main shaft.

Another example of the unit with engine type is seen in the
Grant-Lee three-speed gear box, Fig. 274, as utilized in the Hackett
car. This is unusually small and compact, as will be noted by com-
paring the size of the unit with the operating levers and pedal. While

Digitized by

Google

386

GASOLINE AUTOMOBILES

Digitized by

Google

GASOLINE AUTOMOBILES

387

the clutch is not shown, its housing is, also the flange which attaches
it to the flywheel housing to complete the power unit. A third
example of the engine-unit power group is shown in Fig. 275, which
shows the flywheel, clutch, and transmission of the Peerless eight.
This unit transmits many times the power of the Hackett unit and
is therefore much larger. In this unit the bearing arrangement is
rather unusual, as roller
bearings of the taper form
are used on the main shaft,
a straight roller for the
spigot bearing, and plain
ball bearings for the lay-
shaft. The shortness and
large diameter of the
shafts should be noted.

Additional transmis-
sions in a unit with clutch
and motor will be seen
, under Clutches, in Figs.
251, 252, and 254.

Amidships Alone or
with Clutch. The amid-
ships unit joined with the
clutch, shown in Fig. 253,
represents the Winton
transmission and clutch.
This is not a common con-
struction on pleasure cars,
although it is used on
quite a number of trucks.
On the amidships-clutch
unit type, however, the
combination is not quite so
intimate as the one in which the two units are enclosed in a common case.

Amidships Joined with Driving Shaft. The amidships unit
joined with the forward end of the driving shaft is well shown by the
Locomobile, Figs. 271 and 272. The universal joint with the driving-
shaft pivots is seen at the left side of both these views. In this

Fig. 274. Gear Box Used in Hackett Cars Is Very

Small and Compact

Courtesy of Harkett Motor Car Company,

Jackson, Michigan

Digitized by

Google

388 GASOLINE AUTOMOBILES

construction, which is more widely used than the other amidships
arrangement, there is usually a frame cross-member at the point on
which the rear end of the transmission is supported. This same
arrangement is used on the Stearns-Knight four-cylinder chassis, the
transmission of which is shown in Fig. 276. In this transmission
the stiffness of the cross-member at the rear end of the transmission
is also utilized to support the brake drum of the foot-brake system.

Fig. 275. Gear Box and Clutch of Peerless Eight
Courtesy of Peerless Motor Car Company, Cleveland

The short stiff shafts on the transmission will be noted, also the many
splines on the main shaft and the use of double row ball bearings on
the main shaft, with a flexible roller on the spigot, and the same type
of bearings on either end of the layshaft, which is alongside of the main
shaft. Note also the means provided for adjusting the countershaft
longitudinally by the two steel screws projecting through the bear-
ing caps so that this adjustment can be made from the outside.

Digitized by VjOOQIC

GASOLINE AUTOMOBILES 389

Rear Unit vrith Rear Axle. The position at the rear axle is
not as widely used as a couple of years ago, but those manufacturers
using it have large outputs, so that a considerable number of these
cars are in use and considerably more are being added each year.
One of these, the Studebaker, is shown in Fig. 277. This is a shadow
drawing of the rear axle and transmission, showing the upper, or
main, shaft of the transmission in full and the layshaft which is below

Fig. 276. Three-Speed Transmission and Brake of Stearns Four-Cylinder Car
Courtesy of F. B. Stearns Company, Cleveland, Ohio

it, partially. As will be noted, this position of the transmission
calls for two operating rods, each the full length from the operating
levers to the rear axle. The rod on the left operates the reverse
and first speeds and that on the right second and third, or high, speeds.
To make this shifting of gears and connection of levers with
the actual position of the gears plain, Fig. 278 is also shown. In
this figure the gear-shifting lever is placed in the center and is shown
solid in the neutral position and lighter in the other four positions.

Digitized by

Google

390 GASOLINE AUTOMOBILES

Just below it, the transmission is shown with the position of the
gears for neutral, while in the four corners, corresponding to the four
positions of the lever, the positions of the gears when the lever
is in each one of the positions are shown. These positions indicate
that there is a driving gear and two sliding

Fig. 277. Studebaker Transmission Combined with Rear Axle
Courtesy of Studebaker Corporation, Detroit, Michigan

member is moved forward to mesh with the second gear on the lay-
shaft, as shown in the diagram at the lower left-hand corner, and first,
or low, speed results. With this gear in its neutral position — as it
is left when the shifting lever is swung through the neutral position

Digitized by

Google

GASOLINE AUTOMOBILES 391

and over to the right — a further movement to the front picks up the
forward sliding gear and moves it back into mesh with the third gear
on the layshaft; this combination, as shown in the upper right-hand
corner, gives second speed. When the lever is moved back, it moves

Fig. 278. Diagrams Showing Working of Studebaker Transmission

the gear forward, giving high speed and direct drive, as shown at the
lower right-hand corner.

Interlocking Devices. Nearly all transmissions have a form of
stop lock on the shifting rods in the transmission, which holds the
gears in mesh as soon as they have been moved by the operator
until he moves them again. In reality this arrangement simply
prevents the gears from jumping out of mesh. Generally, the most
simple arrangement which will hold the gears is used. In the ordinary

Digitized by

Google

392

GASOLINE AUTOMOBILES

form this arrangement consists of hardened steel wedges with light
springs back of them and deep grooves in the shifting rods into which
these wedges fit.

In Figs. 271 and 272, the notches in the shifting rods can be
seen plainly. In Fig. 275, the bolt head A indicates the location
of one of the shifting locks. In Fig. 277, A shows the notches in

Fig. 279. Various Forms of Transmission Interlocks

the low and reverse rod and B those on the second and high-speed
shifting rod.

Not all transmissions l^ve the wedge and notch, as Fig. 279
indicates. This figure shows: at A, a method of interlocking by
means of a pin at the shifting forks (not rods) which project into
shallow holes in the two shifters; at B, a rocking, or tilting, bar
beneath the shifting forks, which is pressed into a notch in either
fork when moved from neutral; and at C, the use of a steel ball — all
three arrangements being used by the American Die and Tool
Company. The form at D shows the pin used by Grant-Lee Gear

Digitized by

Google

GASOLINE AUTOMOBILES

393

Company, the grooves in the rods being deep enough to accommodate
this form in a neutral position so that the rod can be started. But the
guide hole in the central housing in which the pin is moved across by
the motion of one rod, owing to the shape of the bottom of the groove,
prevents the other rod from moving.

Electrically Operated Gears. In substance, the electrically
operated transmission has all the hand levers, rods, and other levers
replaced by a series of push buttons. When it is desired to change
speeds, even before the actual change is necessary, the driver presses
the button marked for the speed he thinks he will require. Then,
when the actual need becomes apparent, he throws out the clutch
and immediately drops it back again, all this forming but a single
forward and back movement of the
foot. During the slight interval while
the clutch is out, the electrical connec-
tions shift the gears automatically, so
that when the clutch is let back, the
gears are meshed ready to drive.

Principle of Action. To explain
this action briefly, the gears are moved
by means of solenoid magnets, which
are nothing more than coils of wire,
through which an electric current from
a convenient battery is allowed to pass.
Through the center of each one of these
coils passes an iron bar. When a cur-
rent passes through the coil, it is con-
verted into an electromagnet and draws the iron bar inward. As the
other end of the bar is connected to the gear to be shifted, this move-
ment of the bar shifts the gear. Consequently, when the button is
pressed so that current flows through one of the coils, that action
shifts the gear for which the button is marked.

By referring to Fig. 280, this action will be made more clear.
The diagram shows but one pair of gears to be meshed, and the
battery, push button S, coil D, iron bar P, and clutch connection
M are all shown as dimply as possible. When button S is pressed,
(current through the coil D will draw the bar P and mesh the
gears as soon as the clutch has been thrown out, thereby closing

Fi«. 280. Sketch Showing How a

Solenoid Moves a Gear When

Current Flows

Digitized by

Google

394

GASOLINE AUTOMOBILES

the circuit at M. The application of this to an actual transmission
is shown more in detail in Fig. 281, which shows the clutch pedal

Fig. 281. Arrangement of the Solenoids and Pedal in the OH Electric Gear Shift

and its connection to the six solenoids necessary to produce four
forward speeds, one reverse speed, and a neutral point.

On the steering wheel, Fig. 282, the control group cf six buttons
will be noted on the small round plate at the center, with the addition
of the horn button in the center. In Fig. 283 is another arrangement.

In the 1916 forms of electric-control systems, the buttons are
grouped in one instance on the top of a small box four or five inches

Fig. 282. Arrangement of Buttons
for Gear Shifting

Fig. 283. Another Arrangement of Buttons
for Gear Shifting

square, which is placed on the steering post below the wheel; in
another, on the dash ; and in a third, on a rod connecting post and dash.

Digitized by

Google

GASOLINE AUTOMOBILES 395

Pneumatic Shifting System. The pneumatic system of gear
shifting is along lines somewhat similar to the electric system, air
under pressure being used to move the gears instead of a hand lever
and rod combination. For this purpose it is necessary to add an
air compressor, a tank to carry the compressed air, and what is
called the "shift" — really a complicated valve and a series of plungers
— to the car. The valve and plungers respond to a finger lever on the
steering wheel, the same as the electric system responds to the but-
tons. Air is admitted behind the plungers, which moves the gears
as soon as the clutch is depressed. It is seen, therefore, that this
system, like the electric shifter, permits the anticipation of the
needs of the car.

Railway Car Needs. All transmissions previously presented
have had but one reverse. For gasoline railway cars, the inability
to turn the car requires as many reverse speeds as forward, which
means special gearing. Usually, this gearing is accomplished by
means of a pair of bevels, each with a clutch, meshing with a single
driving bevel. Obviously the two driven bevels will turn in different
directions, and each will drive when its clutch is engaged. By
shifting the clutch to the one which gives a forward speed, all the
speeds of the gear box become forward speeds; by shifting to the one
which gives reverse, all the speeds become reverse speeds.

INDIVIDUAL CLUTCH

General Types Used. While the number of adherents to the
individual-clutch type of transmission is not as great as that of either
the progressive or selective types of sliding gear, it holds its own;
and, as time passes, it gains adherents. In this form, all the gears
are in mesh at all times, and what has been called "the barbarous
and unmechanical" method of clashing gears is entirely done away
with. The individual-clutch type is operated on the selective plan
but otherwise has nothing in common with the latter.

The forms of clutches used vary greatly, as might be expected.
The following are in use today: jaw clutches (both two- and
multiple-jaw); internal-external gears, multiple disc, cone, and
friction clutches other than the multiple-disc form.

Using Internal Dogs. One type in which the gears are engaged
by internal dogs — the gears being in mesh at all times — has four sets

Digitized by

Google

396 GASOLINE AUTOMOBILES

of gears, those on the main shaft being keyed or otherwise fixed to
the shaft, while the gears on the jackshaft run idle except when the
gear-shifting lever is moved forward to an engaging position, which
throws an internal dog up into a slot inside the gear. This position
makes the gear one with the shaft, and the power is transmitted
directly. The dogs in the latest form of this transmission take the
form of hardened and ground steel balls.

Disc Type. Many of the early individual clutch types of trans-
missions used discs, each gear having its own set and each set having
sufficient surface to carry the whole power of the motor. While
bulky, this had undeniable advantages, for it allowed starting on
any gear.

Contracting-Band Type. While advocates of discs are numerous,
other devices do not lack friends. Fig. 284 shows a form on the

Haynes-Apperson
cars that attained much
popularity. In it the
clutching action is pro-
duced by means of con-
tracting bands working
on large diameter drums,
the drums being keyed
each to its own gear. The
full explanation of the

Fig. 284. Early Form of Hayncs Clutch Gear** action ISasfoUoWSI The

engine drives the shaft A, upon which are mounted the gears C, D, E t
and F. These are all permanently fixed to the shaft and rotate with
it. Upon the driven shaft B are mounted an equal number of gears
meshing with the former, but all loose upon the shaft so as to spin idly.
Bolted to each of the latter gears is a large drum, while close to it is a
framing upon which is mounted a contracting band. The latter fram-
ing is keyed to the shaft, so that when it is rotated the shaft must
turn with it. In action, then, when any speed was desired, the band
was contracted until it seized the drum bolted to the gear which gave
that speed; thereupon, the gear, drum band, and framing all turned as
a single piece.

Single-Disc Winixm. Winton long advocated the individual
clutch gear, his clutch taking the form of a single disc pressed

Digitized by

Google

GASOLINE AUTOMOBILES

397

against the gear by means of numerous fingers, Fig. 285. A conical
sliding piece or J expanded the fingers pivoted on M and H 90 that
they pressed against the
disc within the gears D,
K, or N.

Internal-External Gear
Type. Many of the gears
already given date back
several years, but the
gear illustrated in Fig.
286 is more modern,
and is being used today
by the International
Motor Company of New York City and of Allentown, Pennsylvania.
The principle upon which this gear works, as shown by Fig. 286,
is that of the internal-external gear. The gears which transmit the
power are always in mesh. Each one of these is bushed and runs idly
upon the main shaft. Contained within each gear and an integral
part of it is an internal gear of twenty-four teeth. Sliding on the

Fig. 285.

Early Form of Winton Individual
Clutch Transmission

Fig. 286. Mack Commercial Car Individual Clutch Type of Gear Box
Courtesy of International Motor Company, New York City and Allentown, Pennsylvania

squared shaft are four 24-tooth gears; these are specially built for easy
engaging with the internally cut gears.

To follow the letters placed on the parts of this gear, high speed

Digitized by

Google

398 GASOLINE AUTOMOBILES

is obtained by sliding the piece 2-C-31 forward into gear 2-C-34;
this action swings the piece, shown dotted beneath, so as to throw
out the clutch on the lay shaft 2-C-52. On high speed, the two gears
locked together are the only ones to turn, all others being idle. The
same piece 2-C-31, when slid to the right, meshes with the internal
gear of the second-speed pinion 2-C-160. This sliding member slides
upon a squared shaft, so the drive is positive. The action of the first,
or slow speed, ^nd reverse are the same as those just described, being
produced by the shifting of the clutch member 2-C-€6. Attention is
called to the ball bearings used on this transmission, which are
remarkable only when it is remembered that this is a commercial truck
transmission. Students of automobile construction will find many
interesting constructional details in this illustration, which is a repro-
duction of the manufacturer's working drawing.

Still another similar form uses three cone clutches in the trans-
mission, that for the high speed being augmented by a set of pins,
or dogs, which, as the clutch gradually takes hold, slip into an equal
number of holes in the driven gear. In this way, the two are made
as one, which makes slipping impossible — a very important feature.

Transmission Operation. As has been pointed out previously,
practically all transmissions operate all gears by means of a long hand
lever, placed either at the side of the car or in the center, according
to the location of the control. Even on planetary forms, still to be
described, at least one of the various speeds is controlled by a hand
lever. The electric- and air-shifting methods have made a start, and
a good one, but until their number increases materially, these types
can be considered as only having started their development.

Transmission Lubrication. A fairly heavy lubricant is gener-
ally recommended for gear-box use — either a special form of about the
right consistency, or else a home-made mixture of about half-and-
half of light oil and hard grease. Some firms recommend a graphite
grease. The lower part of the case should be filled to a point, or
level, where the largest gears dip continuously. This will insure a
constant agitation of the lubricant, which will thus get to all moving
parts and surfaces. Having the lubricant too stiff is bad, because then
the gears simply cut a path through it without moving the rest.
This results in all other parts running practically dry. Too thin a
lubricant or too much of it will make a fairly heavy drag on the motor,

Digitized by

Google

GASOLINE AUTOMOBILES 399

which loss of power should be avoided. Gear-box lubricant generally
is introduced in bulk by the removal of the cover, usually of a large size
to allow of this. The outside parts carry their own grease and on cups.

Transmission Bearings. By looking back at the various trans-
missions shown, it will be noted that ball bearings are used most
freely. Roller bearings in various forms are coming into use, as the
shorter series produced in the last couple of years has shown
designers that thist ype would produce a compact gear box, their size
having previously limited their use. Plain bearings are not used at
all on good cars.

Transmission Adjustments. Few adjustments are needed in
the modern gear box. However, provision for wear is made in the
operating rods and levers, both within the case and without. In
some cases the shafts may be slightly shifted endwise to secure
better meshing of the gears after wear. Bearings, too, are arranged
to shift slightly in an endwise direction to take care of wear in other
parts and not so much in the bearings themselves.

PLANETARY GEARS

Method of Action. The planetary, or epicyclic, form of gear-
ing offers many advantages, but, strange to say, the American
people, although inclined toward simplicity and cheapness in com-
bination, will not have it in this form, and, as a consequence, this
excellent gear-reducing means is fast losing favor. The principle
upon which all planetaries work is as follows: Connected to the
engine is the first gear of the train. The second is one of a series of
several gears; these are pivoted in a drum, which may be held station-
ary by a brake band. The middle, or third, gear in the train, as well
as the last, or fourth, is connected to another gear, a driven gear, not a
driver. Considering but a single rotating train — there usually are
three or more — the last-named gears form the fifth and sixth in the
whole train. Gears two, three, and four have different numbers of
teeth, as well as gears one, five, and six. Holding the band which
holds the drum to which the gears are pivoted, allows each of them
to rotate around its own axis, but not around the main shaft. This
form of rotation gives one gear reduction.

Another band holds another gear stationary and allows the
three-gear unit to rotate around the main shaft as an axis; at the

Digitized by VjOOQIC

400 GASOLINE AUTOMOBILES

same time it leaves them free to also rotate around their own axis.
This produces another gear reduction. Another form which is
popular in so far as planetary gears are popular is that in which
internal gears are substituted for one set of the planets, from which
the device obtained its name. This does not complicate the device
any; in fact, the only way in which it makes any change is in the

Fig. 287. Drawing Showing Ford Planetary Trans miaaion

manufacturing cost of the gear, internals costing more than spur
gears.

Ford Planetary Type. Ford has been a consistent user of the
planetary gear; in fact, the simplicity and ease of operation of his
well-known and widely used car is largely due to this use. The Ford
transmission, which is of the all-spur-gear type, is shown in Fig. 287.
This is operated by means of two pedals and a lever, one pedal
working high and low speeds, while the other pedal controls the
reverse. The first-named pedal, however, must be used in conjunc-
tion with the forward movement of the hand lever which locks the
high-speed clutch, seen in this figure at the right.

Digitized by

Google

GASOLINE AUTOMOBILES

401

FRICTION DISC

Undoubtedly, when simplicity is sought regardless of cost, the
friction drive is the drive used. The cost with this form is not one
of money, but rather of other things which must be sacrificed if
friction drive is used.

Spur Type. In the interest of simplicity, it may be said that
the friction form of drive dispenses with the clutch, being of itself
both clutch and change-speed gear. The usual form which this takes
is the single spur wheel contacting with another flat-face wheel.
Since these must be at right angles, the car is nearly always chain
driven, the driving wheel
being on the rear end of
the crankshaft, and the
driven shaft across the
middle of the car. To
secure a more certain
drive and at the same
time obtain the differ-
ential action, the cross-
shaft, mounted upon two
independent shafts, is
often fitted with a pair
of wheels, contacting
with opposite sides of
the driver. As this
method causes the two
driven shafts to turn in
opposite directions, a gear is necessary at the end of one of them.

The greatest feature of the friction drive is the multiplicity of
speeds obtainable, these being infinite in number, since every dif-
ferent position of the driven wheel on the driver results in a different
ratio and, consequently, a different speed. To obtain these various
changes, the wheel which meets the other edge-on is usually arranged
to be advanced up to and withdrawn from the wheel presenting the
flat surface. In action, a motion of translation is given to the wheel
at the same time as the motion up to or away from the surface. This
motion of translation changes its position and consequently its
speed.*

Fig. 288. Friction Transmission with Bevels

Digitized by

Google

402 GASOLINE AUTOMOBILES

Over the three-wheel arrangement, the use of the four-wheel
arrangement possesses some undeniable advantages, particularly if
the two parallel driving wheels are arranged to drive the others in
pairs. This arrangement makes the direction of rotation of the
wheels alike, and no intermediate gear to change the direction of one
shaft is needed. A simplification of this form utilizes the flywheel of
the engine as the forward driving disc.

Bevel Type, Bevels have many advantages over spur friction
wheels. They are found in combinations, such as a single pair of
bevels or three bevels, and in multiple combinations, without limit to
the number of bevels. Fig. 288 shows the use of a single pair, but
in combination with a flat face on one and a spur attached to the
other; this makes the whole consist of four wheels in reality.

Another combination sometimes used is that of three bevels.
One of the bevels has a flat face and a spur, making really five wheels.
The spur wheel in every case takes the final drive. A direct drive
on the high gear is obtained by the use of a cone clutch on this spur
and another clutch w T ith which it engages on the driving wheel. One
bevel gives forward speeds, and through the other the various reverses
are gained. The friction drive, although theoretically the simplest
and most ideal form of drive, is not very popular.

MISCELLANEOUS TYPES

Freak Drives. What are termed the freak drives attract much
attention from inventors, but little from hard-headed constructors.
Thus, the belt drive was once advanced as the simple drive, yet it
made no progress. Today there are few belt drives used in final
driving in America, although a few are still made in Europe. There
is a low-price French car, Fouillaron, with this drive; and a single-
cylinder Italian car, the Otav, selling for the equivalent of $150,
which is also equipped with a belt drive.

Cable and Rope Drives. When cycle cars were first brought
out and by many considered as destined to replace both the low-
priced cars, on account of their still lower price and simplicity; and
motorcycles, because of their greater comfort, superior appearance,
and greater carrying capacity, many of the simple drives were
revived and applied to the cycle cars. The types used include the
cable drive, which attracted much attention at one time in th^motor-

Digitized by

Google

GASOLINE AUTOMOBILES 403

buggy field, the rope drive, the flat belt, the V-belt, the cloth-covered
chain, and many others. With the collapse of the cycle-car boom,
these went out of use.

Hydraulic Gear. Janney-Williams. The hydraulic transmis-
sion has been advanced as a cure for all automobile troubles, rep-
resenting as it does the elimination of clutch, differential, and the
driving mechanism. It consists of a pump to circulate the fluid, and
one or two motors, usually attached to the rear wheels and propelled
by the fluid. In the Janney-Williams hydraulic gear, which has
been successfully used for some time in other fields, but has just
recently been tried for automobiles in England, there are three
similar pumps, one being used as a pump and the other two as motors.
By rotating the driving ring so that it assumes different angular
positions, the throw of the small pistons, of which there are nine in
all, is varied from zero up to a maximum. Since the action of the
fluid in the motors connected to the wheels is opposite to this, it
amounts to varying the speed, the number of changes being infinite,
as in friction gearing.

Manly. Another hydraulic drive, of equal merit and of Ameri-
can manufacture, is the Manly. This differs from the Janney-
Williams only in the form of the motors; the fluid and its use are the
same in both cases. This drive has for its object the securing of any
desired speed of the driven shaft, either forward or backward, with-
out changing the speed or direction of motion of the driving shaft
and of transmitting the power to a shaft, which is either in line with
the driving shaft or which lies at any angle to the driving shaft and
is separated from it. It consists of a multi-cylinder pump having a
variable stroke, which is attached to the driving shaft, and of one or
more multi-cylinder motors having a fixed stroke, which are attached
to the driven shaft, together with pipe connections, or passages,
between them for transmitting the working field. The various
cylinders, both of the pump and motors, radiate equidistantly from
a central crank chamber, and the pistons or plungers are connected
to a single crankpin which is common to all. The fluid used is
ordinary machine oil, its lubricating qualities and freedom from the
danger of freezing admirably fitting it for such a purpose. When the
system is once filled, the oil is used over and over again, being in con-
tinuous circulation from pump to motor through one set of pipes, or

Digitized by

Google

404 GASOLINE AUTOMOBILES

passages, and back again from motor to pump through another set.
The stroke of the pump may be varied at will, but that of the motor
is fixed. The variation of the pump stroke is accomplished by a
crank, on which an eccentric bushing is mounted. By revolving the
bushing with reference to the crank, its center line is brought into
alignment with the center of the shaft, and when this position is
reached, no reciprocating motion is communicated to the pump
plungers. The Manly is constructed under license by the American-
La France Fire Engine Company, Elmira, New York, and has proved
its worth on very large trucks and on some of their fire apparatus.

In recent years a number of hydraulic transmissions have been
brought out, but all these face the fundamental difficulty that when
the pump chamber is liquid tight the friction is excessive.

Pneumatic Drive- There has been some talk of a pneumatic-
drive also, this idea not differing greatly from the previous one of
using liquids. In this scheme a large tank of compressed air is
provided for the purpose of starting the engine, helping to get up
speed quickly, and for use on hills when excess power is needful
or at least helpful. If used as planned, it would allow of the elim-
ination of the reverse and would be utilized for braking as well,
the present form of band brakes being replaced by air brakes. This
is but a prospective scheme, never having been tried ; yet in consider-
ing the future, it is worth more than a passing thought because of
its latent possibilities.

Electric Drive. To speak of an electric drive sounds peculiar,
yet that is what should be used for a final drive through the medium
of electric motors. This form, spoken of abroad as the petrol-electric
car, is attaining much headway there. It gains slowly, it is true,
but, nevertheless, surely — each year seeing one or more makes
added to the already long list of successful cars in this category.

In the petrol-electric cars, the generator is coupled to the engine
in the place ordinarily occupied by the flywheel and clutch, and the
armature acts as a flywheel. Then the two motors are set on each
side, directly in front of the rear wheels, which they drive through
the medium of spur gears; the whole is enclosed to keep out dirt,
keep in oil, and reduce noise to a minimum.

On the whole, the electric drive is not losing ground, which, in
these days of gasoline shaft-driven cars, is perhaps something gained.

Digitized by

Google

GASOLINE AUTOMOBILES 405

In fact, it might be said that the electric drive possesses so many
advantages which are worth having, even at a sacrifice, and so few
disadvantages that one is safe in figuring that a few more years
will see the number of these drives doubled and possibly trebled.

Electric Transmissions. While the drives just discussed might
be called electric drives and still be precise, the Owen magnetic car,
which is constructed by the Baker, .Rauch and Lang Company,
makes use of an actual electric transmission, the Entz, at one time
used in a Columbia chassis. This is so arranged that all speed
changing is done by a small finger lever on the steering wheel, similar
to the ordinary spark and throttle levers. The wiring formerly gave

Fig. 289. Drawing Showing Section through Owen Magnetic Transmission

seven speeds forward and two reverse, but a later construction will
probably give about twice this number.

As is shown in Fig. 289, this consists of an electric generator, the
field magnet of which is connected to the engine crankshaft and takes
the place of the flywheel, the armature being connected with the
driving shaft. This transmits the turning effort of the engine by
means of the current established in its circuit, due to the speed
difference of its members on what constitutes the high speed. Any
effort exerted by the engine on one member is transmitted, prac-
tically without loss, to the other member, or armature. The clutch-
generator member makes a very elastic clutching and transmitting
means, but cannot transmit more than the full torque of the engine.

Digitized by

Google

406

GASOLINE AUTOMOBILES

For higher torque, use is made of an electric motor, whose
armature is mounted on the driving shaft and receives current from
the first, or clutch, generator.

In the figure, the clutch generator is shown at the left, its field
part marked FR, the field winding FW, and the pole pieces PP.
This portion rotates whenever the crankshaft revolves. Within it is
the armature A secured to the continuous shaft S, which is con-
nected through the joint X with the driving shaft to the rear axle.

The second part of the complete system is shown at the right
and is practically a duplicate of the clutch generator. Its armature
A i is carried on the same shaft S as armature A. Outside this is
the usual field part with rings FR, windings FW, pole pieces, and
brushes B.

Field FR can revolve without any motion of A ; in fact, it is by
varying the relative speed of FR and A that the different speeds are

Fig. 290. Sketch to Explain Working of Magnetic Transmission
Courtesy of Baker-R A L Company, Cleveland, Ohio

obtained. For instance, on direct drive the generator is short-
circuited on itself and carries armature A with it. Then, except for
a slippage of 4 per cent or less, between the field FR and the arma-
ture A, the wheels would be driven as fast as the latter rotated.
Lower speeds are produced by making the slippage greater. Speed
changing, as well as starting and braking, are accomplished by means
of the finger lever on the steering wheel. The storage battery is
charged at a 10-ampere rate.

Perhaps the explanation which follows will give a better idea
to the repair man than the foregoing, which is slightly technical.
The rotating field of the generator, marked FW, is comparable to
a horseshoe-shaped magnet B, Fig. 290, also rotated by the engine.
The armature A at the left-hand, or engine, end of the shaft is com-

Digitized by

Google

GASOLINE AUTOMOBILES

407'

parable to the piece of steel C, which is free to rotate and which will
do so when the field rotates and attracts it. If this were connected
directly to the driving shaft, as Fig. 290 shows the combination

Fig. 291. Second Step in the Magnetic Transmission Explanation

w r ould become a simple electromagnetic clutch and the car would have
but one speed. On the level, one speed would be satisfactory, but
in deep sand, on a heavy grade, or for any other severe pull, the air
space between the rotating field and the armature would bring about
the stalling of the engine.

If we add a conventional
electric motor just back of
C f with its field fixed, or
stationary, as at Z). and its
armature free to rotate with
the armature shaft to which
it is attached, about as shown
in Fig. 291, C will not rotate
as fast as B when meeting a
stiff pull, although it will try
to do so. A wire connects
the commutator of C with
the field coils D, and the
electricity generated by the
rotation of B relative to C, that is, the amount of slippage due to the
air gap, is led through this wire to D where it acts as power, rotating
E faster and thus acting as a booster on the propeller shaft.

Fig. 202. Steering Wheel Quadrant of
Owen Magnetic Car

Digitized by

Google

408 GASOLINE AUTOMOBILES

it
a -8

.a |

> i

Digitized by

Google

GASOLINE AUTOMOBILES 409

By introducing variable resistance in the connecting wire, or
rather series of wires, the speed may be varied from zero to the
maximum, which, as it happens through this booster action, is
considerably in excess of what it would be if the motor were driving
directly through on high speed without any electrical or mechanical
apparatus. The variety of speeds can be anything desired, and this
forms the basis for naming it "The car of a thousand speeds". As
a matter of fact only seven speeds are provided for on the steering
wheel, which is shown in Fig. 292, but it is perfectly feasible to
wire up the car and arrange the quadrant to have twice this number
or any other number, as required. On the steering post quadrant,
the additional positions of charging, starting, and neutral are to
be noted. The neutral position is that in which the engine is idling
and the car standing still; or when the car is coming down a grade,
the wheels are driving the motor which generates current in the reverse
direction, so that the device becomes an electric brake, slowly but
surely reducing the speed of the car. The starting position connects
the storage battery to the generator armature in order to revolve
the engine shaft and thus start it. The charging position can be
used at any time to generate electricity for the storage battery.

While this description sounds very different, the chassis is not
unlike the average gasoline chassis with a mechanical gear shift,
as Fig. 293, showing a view of it from above, brings out. The small
unit just back of the motor is a mechanical reverse gear which it
has been found advisable to use for one reason, because it gives
all the quadrant speeds on the reverse, instead of the usual one.
By this arrangement the car has seven fixed speeds forward and
seven speeds reverse, together w r ith the possible variations of both,
which can be produced by the use of spark throttle and accelerator.

TRANSMISSION TROUBLES AND REPAIRS

Noise in Gear Operation. One of the most common of trans-
mission troubles is a grinding noise in the operation of the gears.
This is heard more in bevels than in spurs, but in old transmissions
and on the lower speeds it is heard frequently. A good way to
quiet old gears, after making sure that they are adjusted rightly
and meshing correctly, is to use a thicker lubricant. If thick oil
is being used, change to half-oil and half-grease or preferably all grease.

Digitized by

Google

410 GASOLINE AUTOMOBILES

In this respect the repair man or amateur worker may take a
leaf out of the book of second-hand car men, who are said to "load"
an old and very noisy transmission gear with a very thick almost
hard grease in which is mixed some shavings, sawdust, cork, or
similar deadening material. When this is done, a graphite grease is
generally used, so that the shavings, cork, etc., would not show in
case it was necessary to take off the gear-box cover. This material
will fill up all the inequalities of the gears and shafts so that tem-
porarily everything fits more tightly, and all the sounding board,
or echo, effect is taken out of the transmission case. This sounding-
board effect is fully as important as the grinding noise, for many
really insignificant noises are magnified by poorly shaped gear cases

Fig. 294. Types of Gear Pullers

so as to appear very loud, indicating serious trouble which need
immediate attention, when such is really not the case.

Another source of gear-set noise is a shaft out of alignment,
caused either by faulty setting, by worn or loose bearings, or by
yielding or cracking of the case. If it is properly set at one end and
is out at the other, the trouble will be more difficult to find and remedy.

Heating. Heating is a common trouble, too, but usually this
can be traced to lack of lubricant in an old car or to too large shafts
or too small bearings in a new one. Sometimes the grease used will
cause heating, particularly when long runs are made with the trans-
mission working hard. This is most noticeable when the grease or
lubricant is of such a consistency that the gears simply cut holes in
it but do not carry any around with them or do not otherwise circu-
late the lubricant. This can be remedied by making it thicker so
the gears will cut it better, by making it thinner so they will splash
it more, or by changing the nature of it entirely.

Digitized by

Google

GASOLINE AUTOMOBILES 411

Gear Pullers. One of the principal necessities for transmission
work is a form of gear puller. These are like wheel pullers, except
that they are smaller and more compact. In Fig. 294, a pair of
gear pullers are shown. The one at the left is very simple, consisting
of a heavy square bar of iron which has been bent to form a modified
U. Then, a heavy bolt is threaded into the back of this or bottom of
the U. This will be useful only on gears which are small enough to
go in between the two sides of the puller, that is, between the sides
of the U, which when in use is slipped over the gear, the screw turned
until it touches some-
thing solid, as the end of
the gear shaft, and then
the turning continued
until the gear is
forced off.

While not as simple
as this, the form shown
at the right has the
advantages of handling
much larger gears, and
also of being adjustable.
As the sketch shows, this
consists of a central
member having slotted
ends in which a pair of
L-shaped ends, or hooks,
are held by a pair of

through bolts. Then p^ ^ Method of Pressing Transmission Gear

there is a central work- onto Ita shaft

ing screw. To use, the hooks are set far enough apart to go over the
gear, then slipped around it and hooked on the back. The central
screw is turned up to the end of the shaft, and then the turning
continued until the gear comes off. There are many modifications
of these two; in fact, practically every repair shop in the land has
its own way of making gear or wheel pullers. At any rate, every
shop should have one.

Pressing Gears on Shafts. The opposite of pulling off gears
is putting them on; very often they are designed to be a press fit,

Digitized by

Google

412

GASOLINE AUTOMOBILES

which means exerting tremendous pressure. Every repair shop
should have some form of press for this and similar work, something
similar to the form shown in Fig. 295. In this figure, the man is just
beginning to apply pressure to the shaft to force it into the lower
gear. The table must be arranged for work of this kind with a solid
spot when the shaft does not come through, and with a hole when it
does. The work of pressing is usually done in a few seconds, while the
preparation, alignment, and starting of the work takes perhaps half
an hour or more. It is work which should be done very carefully.
One way in which arrangement can be made for pressing a
shaft a considerable distance into a gear and, conversely, for pressing

the shaft out of the gear is that
shown in Fig. 296. This figure
has the additional advantages of
being simple, easily constructed,
and cheap. A solid base is
constructed with a pair of
hinged uprights. These can be
dropped together with the work
between them, forming a mod-
ified triangle, the strongest
known shape, resting upon its
broadest side and thus having
the greatest stability. With this
arrangement, the press can
readily be used for pressing off parts.

Care in Diagnosis. The repair man should use a great
deal of care in doping out or diagnosing the trouble in a transmission,
for, frequently, what appears at first to be at fault turns out to be all
right, and something else is back of the first trouble, which must be
corrected before a remedy can be applied. Recently, a repair
man figured that a new gear was needed to repair a transmission.
This was received from the factory three days later, but when he
started to put it in, he found that a bearing was defective; in fact,
the defective bearing caused the wear in the gear. This necessitated
a further delay of three days in order to get a new bearing.

Poor Gear Shifting. A common transmission trouble is poor
gear shifting. This may be due to a number of different things.

Fig. 296.

Home-Made Table for Use in Gear

Pressing or Pulling
Courtesy of "Motor World*'

Digitized by

Google

GASOLINE AUTOMOBILES

413

For one thing, the edges of the gears may be burred so that the edges
prevent easy meshing. When this is the case, any attempt to force
the gears into mesh only burrs up more metal and makes the situa-
tion worse. Whether this is the trouble or not can be determined
very quickly and easily by removing the transmission cover and
feeling of the gears with the bare hand; the burred edges can readily
be distinguished. If this is the only fault, the transmission should
be taken down, the gears taken out and placed in a vise, and the
burrs removed with a cold
chisel and file.

Poor or worn bear-
ings or a bent shaft or one
not accurately machined
may cause difficult shift-
ing. If the bearings are
worn, the difficulty of
shifting will be accom-
panied by much noise,
both in shifting and after.
The bent shaft is more
difficult to find and equally
difficult to fix. A new
shaft is usually the quick-
est and easiest way to
remedy the trouble.

Sometimes the con-
trol rods or levers bind or
stick so that the shifting
is very difficult. In case
the gears are difficult to
"find" or will not stay in mesh, the fault may be in the shifter rod in
the transmission case. This usually has notches to correspond to the
various gear positions, with a steel wedge held down into these notches
by means of a spring. The spring may have weakened, may have lost
its temper, may have broken, or for some other reason failed to work.
Or with the spring in good working condition, the edges of the
grooves or notches may have worn to such an extent as to let the
wedge slip out of, or over, them readily.

Fig. 297.

Tank and Basket for Cleaning Gears and
Other Parts
Courtesy of "Motor World"

Digitized by

Google

414 GASOLINE AUTOMOBILES

Cleaning Transmission Gears. When the transmission is taken
out of the case and has to be taken apart, and particularly if it has
not been cleaned for a long time previously, it is advisable to clean
all the parts thoroughly before attempting to work with them.
• The best way to clean the parts is to have a special cleaning tank.
In Fig. 297 one of these is shown, which is not unlike the baskets
used in some hardening processes. It consists of a deep metal or
metal-lined tank and a basket or tray, which is an easy fit in it,
suspended from above by wire cables. The cables are brought

Fig. 298. Handy Framework for Lifting Transmissions out of Chassis

together on the wall, where a ring joining the ends and a series of
nails or hooks make it easy to hold it at any desired elevation, either
in or out of the tank. The tank is filled preferably with kerosene.
As soon as a part has been removed from the transmission, it is
thrown into the basket, and when this is filled or all the parts are in
it, it is lowered into the kerosene and allowed to stand, for a couple of
hours if possible, but, if not, for as long as can be. When thoroughly
soaked, the basket should be raised above the level of the liquid and
allowed to drain thoroughly. If it can be left for an hour or so to

Digitized by

Google

GASOLINE AUTOMOBILES

415

drain, all trace of kerosene will disappear, while the gears, shafts,
and other parts will be like new.

Lifting Out Transmissions. When the trouble has been found
to be in the transmission case or in some part that necessitates com-
plete removal, it is often a tremendous job to get the unit out. Some
units are attached from below and are not so difficult to detach.
They are lowered by means of a platform of boards set on two or
more jacks. But when it must be removed from above and no
overhead beam is available, the hoist shown in Fig. 298 will be found
very handy. As will be seen from the sketch, this hoist is simply a
triangular framework constructed from angle iron to have the
minimum height which will allow removal of the unit. The chain

Fig. 299.

Two Forms of Useful Transmission Stands
Courtesy of "Motor World*'

fall is attached to a hook in the center, and the chains put around
the case. When lifted up close into the V of the framework, the
whole transmission can be put onto horses and moved along the
chassis, or boards can be put under it and over the chassis frame to
allow it to be worked there. Or, if desired, it can be lowered onto a
creeper or other low platform with wheels and moved out of the way.
This rigging can be used for many other similar purposes, although it
is not suitable for the removal of an engine, radiator, or other part
or unit which extends far above the chassis frame.

Transmission Stands. When the transmission has been
removed, if the work to be done upon it is all extended, a stand to
support it is desirable; in fact, a necessity, if the work is to be done
right. A pair of stands are shown in Fig. 299, the one at the left

Digitized by

Google

416 GASOLINE AUTOMOBILES

is made from pipe fittings and angle irons in such a way that the
width between the rails can be varied to suit the transmission or
engine. The stand at the right is more of a specialized type. It is
constructed for a certain transmission and has clips to support it
in the same way that it is held in the chassis. The latter frame may be
smaller and more compact than the former, but the wide range of
uses to which the former can be put make it more desirable in the
average shop.

Working in Bearings. When a great many bearings of any
one transmission are fitted, it is well to make a jig for working in
the cases to an exact size for the bearings, whether these be over-

Fig. 300. Method of Fitting Transmission Case Bearings with Dummy

sizes or not. Such an outfit, Fig. 300, shows an aluminum trans-
mission case with a pair of jigs for scraping its bearings into the case.
These jigs are made of steel and are constructed to a very accurate
size, the surfaces being hardened so they will show no wear. The
jigs are painted with Prussian blue, put in place and turned, the
markings scraped by hand, the jigs again put in place and turned,
and this process repeated until a perfect bearing surface is obtained.
Starting with an unknown size on the case and a known size of bearing
which must go in it, a few of these jigs will soon save their cost in
labor and time, by quickly producing the necessary size of case to
take the bearings.

Digitized by CjOOQIC

GASOLINE AUTOMOBILES 417

Saving the Balls. If a great many ball bearings, particularly
from transmissions, are used, and many bearings scrapped, it is
advisable to save the balls. These balls will come in handy later for
replacement or other uses.
Moreover, balls are expen-
sive, and good ones are hard
to obtain. A handy way to
take care of balls, without
much work beyond cleaning
thoroughly in the kerosene
tank, is to construct a cab-
inet like that seen in Fig. 301 .
There are four drawers — or
more if desired. The bottom
of each drawer is a steel plate
drilled as full of holes as pos-
sible of the next smaller size, „. „ m v ... , u ,. . T . . tu .

' tig. 301. Easy Way of Sorting and Keeping OKI

that is, a clearance size for „ Bearing Bail*

Courtesy of ''Motor World'

the next round figure size.

Then the cabinet does the sorting, all balls being put into the top
drawer. The next smaller size is retained in the second drawer, the
third size in the next, and so on. When using balls out of these
drawers, the micrometer should be used to determine their exact size.
Handy Spring Tool. In the Ford transmission-band assembly
there are three springs which it is difficult to assemble because of
the trouble in holding so many things at once. To eliminate this
trouble, the tool, shown
in Fig. 302, made from
flat bar stock, can be
constructed. The han-
dles, if they could be
called that, are pivoted
together and carry a kind
of flat jaw with three

, i i Fig. 302. Handy Spring Tool for Ford Assembly

notches at one end.

When the two of these are squeezed together by means of the screw
and handle at the other end, the flat plates will hold the three springs
tightly enough so that all can be inserted in their proper positions

Digitized by

Google

418 GASOLINE AUTOMOBILES

at once by using but one hand. Tools of this kind, which save
a great deal of the workman's time and thus save both time and
money for the owner of the car, should, and in fact do, distinguish
the well-equipped repair shop and garage from the old-fashioned
kind which is in the business only for the money and not too par-
ticular how it is gotten.

In transmissions of the planetary type, there is little or no
trouble except with the bands. If these are loose, the gears will
not engage and the desired speed will not result. If they become
soaked with grease, oil, or water, they will not work as well as if kept
clean and, in the case of excessive grease, will slip continually. If
the band lining becomes worn, it should be treated just as a brake
lining is. When inspected for wear and found not badly worn but
slippery, it may be cleaned in gasoline and then in kerosene, after
which a saw, hacksaw, or coarse file may be used to roughen it.
Sometimes greasy bands can be fixed temporarily — say, enough to
get the car to a place where tools, materials, and facilities for doing
the work are available — by sprinkling them with powdered rosin or
fuller's earth. The former should be used sparingly because it will
cause the band to bite or grab hold when forcibly applied, and at times
has been known to cut into and score a cast-iron drum. As a rule,
planetary transmission bands should be handled in the same way as
ordinary brake bands, as to lining and relining, roughness of surface,
lubrication, etc.

Possible Transmission Troubles. A combination of clutch
and transmission in which the principal troubles incident to these
units are indicated is presented in Fig. 303. In this type of clutch,
the greatest possibilities of trouble lie in the burring of the discs
or in a lack of spring adjustment. If the discs burr, the burrs can
be filed off with a fine file, while the latter trouble is avoided by
merely tightening the spring-adjusting bolt, trying the effect of
this and tightening again, until the correct and satisfactory position
is obtained.

In transmissions, the possibilities of trouble include the following:
burred teeth; gears worn where they slide along the shafts on keys
or in keyways; looseness in the main bearings; and play in shifter
rods or their locks. Where the gears clash, one against the other
in shifting — unless the faces of each have been chamfered and rounded

Digitized by VjOOQIC

GASOLINE AUTOMOBILES 419

off nicely and are well hardened at these points — a cutting action
which gradually wears a high burr in one or both gears is liable to
be set up. When the two are in mesh, the burrs are on opposite
sides and contact with the meshing gear. This contact will make
a continuous noise. Its remedy is the removal of the gear, the
filing off of all raised portions, the filing or grinding out of all low
spots cut into the teeth, and subsequent hardening to make repetition
impossible.

If the gears have worn at the center hole where they slide on
the shaft, either in the round hole or at the keyway, this must be
fixed at once. In the former instance, the gear can be bushed, and

Fig. 303. Transmission Troubles Illustrated

the bushing bored out to fit the shaft, while in the latter, a slightly
larger key may be fitted into the shaft and the keyway may be recut
to accommodate it. Where the keys have been let into the shaft,
they may become worn in one spot or at the ends. If the wear is all in
the key, it can be replaced with another of the same size made slightly
harder in the process.

If the main bearings are of the roller type, the wear may be
taken up by readjusting the position of the roller on the cone, but
if they are of ball or plain bushing form, replacement is almost
the only remedy, unless it happens that in the case of a plain bush the
bush is split, so that something may be filed off of the two contacting
sides, and the holes trued out to this new size. In that case, the

79 Digitized by

Google

420 GASOLINE AUTOMOBILES

advice previously given under the subject of Plain Engine Bearings
will be applicable.

Play in the shifting rods may be traced to one of two things:
looseness at the connection of two rods or of a rod and a lever; or
looseness in the bearings. The former inevitably requires a new and
slightly larger pin driven into the place occupied by the previous
member. Loose bushings will mean new ones if the trouble is serious,
for this form is almost always of the solid and non-adjustable type.
In many cases where wear occurs on a solid plain bearing used on
the end of a plain round shaft, if peening cannot be resorted to,
the shaft may be turned dow f n a very little bit, say ^ inch, the bushing
turned out an equal amount, and a thin sleeve bushing made of this
thickness all around and forced into the previous member. This
saves reboring the case, which is an expensive and difficult job,
while both the shaft and bushing jobs are simple ones.

If a serious defect develops in the case, it may be cleaned out
and welded. This is not a job for the amateur, but the closing of a
simple crack, no matter how long, would be an easy proposition for
the owner of a welding outfit; moreover, it would be a very short
quick job. Autogenous welding should always be resorted to as soon
as a crack or break is detected, for this may save the expense and
delay of a whole new case, the welding costing from 50 cents to $1,
while the new case easily may amount to $50.

SUMMARY OF TRANSMISSION TROUBLES

Lubricating Transmission Gears. The transmission case should
be filled with lubricant to a depth of several inches. Care should be
exercised at frequent intervals to see that a proper amount of lubri-
cant remains in the transmission case. Different makers recommend
different kinds of lubricants for transmissions. In light cars a mixture
often used consists of equal proportions of light grease and machine
oil. In heavier cars a heavy graphite grease is often used. The
proper lubricant depends upon the types of bearings used; thus for
ball-bearing transmissions, no oil need be added.

Change-Speed Lever Indicates Some Impediment in Transmis-
sion. It is desirable to look for broken or mutilated gears, broken
bearings in transmission shafts, sticking or misalignment of gear shafts
or of their operating mechanisms.

Digitized by

Google

GASOLINE AUTOMOBILES 421

Adjusting Annular Bearings. Makers recommend that the
inner race be pinched so tight that movement is impossible; the
outer race is sometimes allowed a little freedom — .002 to .003 inch.

QEARS

Since the whole subject of transmission concerns itself with
gears, it will not be out of place to discuss the gears themselves
and describe the many different kinds in use. Speakjng broadly,
the gears used may be classified according to the position of their
axes, relative to one another. Thus we have axes parallel and in the
same plane; parallel but not in the same plane; at right angles and in
the same plane; at right angles and not in the same plane; at some
other angle than a straight or a right angle and in the same plane;
and the same, but not in one plane. These classes give us the forms
of gear in common use, viz, spur gears, bevel gears, helical gears,
herringbone gears, spiral gears, and worm gears.

TYPES OF QEAR-CUTTINQ MACHINES

Before discussing these various kinds of gears, it may be wise to
familiarize the reader with the special features of different types of
gear-cutting machines. Formerly, the teeth were cut, one gear at
a time, in the milling macb'ne, this being practicajly a hand opera-
tion, since all movements of the gear or cutter had to be made by
hand. Later, improvements made it possible to cut more than one
gear at a time, which resulted in lowering the cost, but did not
eliminate the hand work.

Step by step special machinery was developed for this work,
until finally a perfected machine was brought out which did all the
work. With this machine, the workman placed the cutter on
the machine spindle, set the gear blanks into position, and started the
machine, after which it went on automatically, cutting tooth after
tooth to a correct shape, until the gear was finished, when it was
again necessary for the workman to shut it off and, after taking out
the finished gears, put in a fresh supply of gear blanks.

Many machines have been devised and perfected in recent years
owing to the demands of the automobile manufacturers. By having
a battery of gear-cutting machines handled by a single man, the
cost of gear cutting has been brought down to the absolute limit
in addition to a decided gain in gear accuracy.

Digitized by

Google

422 GASOLINE AUTOMOBILES

Whiton Gear-Cutting Machine. The Whiton automatic gear-
cutting machine is shown in Fig. 304. The cutter is carried by
the spindle A, which is journaled in a saddle B sliding upon the
swinging carriage C, and is capable of adjustment at any angle neces-
sary to cut bevel gears. The machine, as shown, is arranged for
cutting spur gears. The cutter arbor A is driven by the pulley D at

Fig. 304. Automatic Gear-Cutting Machine
Courtesy of D. E. Whiton Machine Company, New London, Connecticut

the back of the machine, acting through a system of gears not shown.
The blank to be cut is held on an arbor fitted into the vertical spindle
E, with its upper end supported by a center in the arm, adjustably
clamped to the column G. The traversing screw // has a graduated
dial. A gage provided centers the cutter, and graduated stops
are used for setting over the cutter in bevel gear cutting and for
setting over the blank. At J are the gears of the indexing mechanism.

Digitized by

Google

GASOLINE AUTOMOBILES 423

Brown and Sharpe Gear-Cutting Machine. Fig. 305 repre-
sents a Brown and Sharpe gear-cutting machine. The gear blank is
carried on an arbor fitted to the horizontal spindle A and supported
by the outer supporting bracket B. The indexing mechanism is in
the rear of the indexing wheel C. The cutter is carried by the cutter
spindle D mounted in the traveling carriage E. In smaller machines
the base upon which this carriage slides is pivoted so as to be

Fig. 305. Number 6 Gear-Cutting Machine
Courtesy of Brown and Sharpe Manufacturing Company, Providence, Rhode Island

set at any required angle for cutting bevel gears. The machine is
entirely automatic in its action. It has an attachment for cutting
internal gears.

Automatic Q ear-Cutting Machine. The automatic gear-cutting
machine built by Gould and Eberhardt is shown in Fig. 306. It is
of the same type as that built by Brown and Sharpe and possesses
some excellent features. The gear blank and cutter are mounted in

Digitized by VjOOQlC

424 GASOLINE AUTOMOBILES

a similar manner, and the adjustments are made at much the same
points. It is furnished with attachments for hobbing worm gears
and for cutting racks and internal gears. The one shown is not
adapted for cutting bevel gears.

Becker Gear-Cutting Machine. The Becker Milling Machine
Company gear-cutting machine, Fig. 307, is of the milling-machine
type. It was designed by Amos H. Brainard, a builder of milling
machines. The gear blank is mounted upon an arbor fitting a taper

Fig. 306. " New Type" Gear-Cutting Machine Entirely Automatic for Cutting Spur Geare Only
Courtesy of Gould and Eberhardt, Newark, New Jersey

hole in the work spindle A or fixed upon an arbor and mounted on
centers. The cutter is mounted upon a cutter arbor B journaled in a
sliding saddle C whose support D is pivoted to the machine knee so as
to be adjustable to any angle required for cutting bevel gears as well
as spur gears. The machine is entirely automatic in its action.

Fellows Gear Shaper. The Fellows gear shaper, shown in
Fig. 308, is a distinct type in construction and action. The gear
blank is mounted on the vertical work spindle A, which has on its
lower end and within the casing B an indexing worm gear operated by

Digitized by VjOOQIC

GASOLINE AUTOMOBILES 425

the change gears at C. These are driven from the cone pulley D by
means of the vertical shaft E with a very gradual but continuous
motion as the vertically reciprocating cutter F forms the teeth on
the blank, gradually rotating in unison with the rotation of the blank.
The reciprocating movement of the ram carrying the cutter is pro-
duced by suitable mechanism within the casing H operated by the
shaft G. The machine is automatic in its action and cuts spur gears

Fig. 307. Gear Cutter
Courtesy of Becker Milling Machine Company, Hyde Park, Massachusetts

and internal gears. A modified form of machine is adapted to cutting
the teeth of racks. The cutting action is that of planing.

G Season Gear Planer. The Gleason gear planer is shown in
Fig. 309. It is an excellently designed machine with a single tool
having a narrow rounded cutting point for planing gear teeth. The
gear blank A is mounted on a horizontal spindle having at its rear
end a suitable automatic indexing mechanism J5. The tool C is
carried in a reciprocating tool block D which travels upon a swing-

Digitized by

Google

426 GASOLINE AUTOMOBILES

ing carriage pivoted at E directly under the apex of the base cone of
the gear blank. The exact curve and direction of its feed are con-
trolled by one of the formers, mounted upon the triangular former
carrier, which may be rotated so as to bring either former up to its
operative position, making a rest and guide on the outer end of the
swinging carriage for the friction roller K. Of the three formers, one

Fig. 308. Gear Shaper
Courtesy of Fellows Gear Shaper Company, Springfield, Vermont

is used for a roughing cut, and the other two for the upper and under
sides of the tooth. Being placed at a considerable distance from the
pivot upon which the carriage swings, they are made many times
larger than the tooth, and great accuracy of form is thereby secured.
The roughing cut is frequently made with a rotating cutter on an
ordinary gear-cutting machine. Modifications of this machine are
built upon the same principle specially for cutting spur gears.

Digitized by

Google

GASOLINE AUTOMOBILES 427

Bilgram Gear-Planing Machine. The Bilgram gear-planing
machine, shown in Fig. 310, operates upon a principle similar to that

Fig. 309. Gear Planer
Courtesy of Oleason Tool Company, Rochester, New York

Fig. 310. Gear-Planing Machine

of the machine just described, but with this important difference.
In the Gleason machine, the tool moves so as to trace the exact
contour of the side of the gear tooth, in addition to its reciprocating

Digitized by

Google

428 GASOLINE AUTOMOBILES

movement for cutting. In the Bilgram machine, on the other hand,
the tool has only a reciprocating motion, while the gear blank and
its supporting mechanism are given the rolling motion similar to that
imparted by one rotating gear to another, which is that of a rolling
cone. To accomplish this motion, the axis must, in the first place, be
moved in the manner of a conical pendulum; therefore, the bearing
of the arbor which carries the blank is secured in an inclined position
between two uprights to a semicircular horizontal plate, which can be
oscillated on a vertical axis passing through the apex of the base cone
of the blank. To complete the rolling action, the arbor must, in the
second place, receive simultaneously the proper rotation; this effect
is produced in the machine by having a portion of a cone (correspond-
ing with the pitch cone of the blank), attached to the arbor and held
by two flexible steel bands stretched in opposite directions, one end
being attached to the cone and the other to a fixed part of the mech-
anism, thus preventing this cone from making any but a rolling motion
when the arbor receives the conical swinging motion. In the^ngrav-
ing, A is the blank to be cut, B the ram carrying the cutting tool, and
C the indexing and rolling mechanism.

TYPES OF QEARS IN AUTOMOBILES

Spur Gears. A spur gear is not only by far the most common
kind of gear, but is also the easiest to describe, consisting, as it does,
of a round flat disc with teeth cut in its circumference, i.e., around
the periphery of the disc, as shown in Fig. 311.

Bevel Gears. Bevel gears, in which the shafts are at right
angles and in the same plane or in the same plane but not at
right angles, are more difficult to cut and are therefore less used.
They are now cut, like the spurs, in an automatic or nearly automatic
machine, which requires little attention, but which does require
more care than the spur-gear machine. Both spurs and- bevels
sometimes require a chamfered tooth edge; spur gears as used in the
Panhard, or clash-gear, transmission are always in need of it. This
work was formerly done by hand, but now a special machine has been
manufactured for this purpose.

There are no real restrictions against the use of the spur and
bevel, either or both being used interchangeably. Very often they
are used in combinations which appear peculiar, as the one shown

Digitized by

Google

GASOLINE AUTOMOBILES 429

in Fig. 31 1. This is the final drive and reduction gear of the Autocar
commercial cars, made by the Autocar Company, Ardmore, Penn-
sylvania. In this gear, it will be noticed that the drive from the engine
is through bevels to an intermediate shaft and that the final drive
is by spur gears.

Helical and Herringbone Gears. In situations where quiet
running is deemed necessary, the use of a helical gear frequently finds
favor, since it accomplishes the desired result, although the cost of

Fig. 311. Combination of Gears in the Autocar Final Drive

cutting is high. Of late, these gears have come into general use for
camshaft drives and similar places. A pair of helical gears set so tl\at
the helices run in opposite directions forms a herringbone gear.
This is even more quiet in its action than the single helix and pos-
sesses other virtues as well. One well-known firm has adopted it for
camshaft driving gears and makes it as described to save cutting-
cost, as the cost of cutting a true herringbone would be prohibitive.
So a pair of helical gears of opposite direction are set back to back and
riveted or otherwise fastened together, forming a herringbone gear at
a low cost. Both of these may be used when the two shafts are par-

Digitized by

Google

430 GASOLINE AUTOMOBILES

allel and in the same plane, but for all cases where the shafts are
neither in the same plane nor parallel, some form of spiral gear must
be made use of.

Spiral Gears, Spiral gears, as such, are not generally under-
stood, but that variety of the spiral known as the toorm gear is
very simple and easily understood and it has attained much popu-
larity within the past few years. This popularity has been due, in
part, to superior facilities for cutting correct worms and gears, but, in
the main, to a superior knowledge of the principles upon which the
worm works and of the things which spelled failure or success. Thus,
one of the earliest experimenters in this line laid down the law that the
rubbing velocity should not exceed 300 feet per minute if success was
desired or in rotary speed about 80 to 100 revolutions. For auto-
mobile use, this was out of the question; but later experimenters
found that these results only attached to the forms of gear used by
the early workers and did not apply to a strictly modern gear laid
down on scientific principles.

The mistake made was in the pitch angle of the worm, which
was formerly made small, nothing over 15 degrees being attempted.
This was the item that was at fault and that caused this very useful
and efficient mode of driving to fall into disuse. As soon as this
fact was ascertained and larger pitch angles utilized, better results
were obtained, until, with 20-degree angles, 700 feet per minute pitch-
line velocity was attained, followed shortly by the use of even higher
angles, resulting even more successfully. As the efficiency depends
directly upon the pitch angle, these changes brought the efficiency
of this form of gearing from the former despised 30, 40, and some-
times 50 per cent up to 87, 88, and even 90 per cent, thus putting it
on a par with all but the very best of spur gears and above bevel
goring. In fact, in the light of modern knowledge of worm gears,
it could easily be said, without departing from the truth, that it
is possible to obtain from this form an efficiency of 93 per cent. In
automobile work, the worm gear has been used mostly for steering
gears and final drives. In the former, its irreversible quality is
brought out, while in the latter, this quality must be made subordi-
nate to a great reduction, which may be attained in a very small
compact space. Many modern machines make use of worm gears.
Some of the users are: the Jeffery, Baker, Detroit, Hupp- Yeats, and

Digitized by

Google

GASOLINE AUTOMOBILES 431

Woods electrics; Pierce, Packard, Riker, Mack, Atterbury, Blair,
Chase, Gramm, G.M.C., Hulburt, Moreland, Standard, Sterling, and
other trucks; Dennis (English) busses and trucks and Greenwood and
Batley (English) trucks.

Fig. 312. Rear View of Timken Worm-Driven Rear Axle
Courtesy of Timken-Detroit Aide Company, Detroit, Michigan

Spiral Bevels. The spiral bevel is a new development, having
been brought out in 1914 as a compromise between the worm and the

Fig. 313. Worm Gear Applied to Rear Axle Drive of Touring Car

Fig. 314. Worm Used on Locomobile Trucks
Courtesy' of Locomobile Company of America, Bridgeport, Connecticut

straight bevel. As such, it is supposed to have practically all the
advantages of both, except that it does not afford the great speed

Digitized by

Google

432 GASOLINE AUTOMOBILES

reduction that can be accomplished with a worm in the same space,
being more like the bevel in this respect.

Among those using the spiral bevel are the Packard, Cadillac,
Reo, Stearns-Knight, Velie, Kline, Apperson, Buick, Chalmers,
Chandler, Cole, Haynes, Hupmobile, Jackson, King, Locomobile, and
many others. Figs. 312 and 313 show applications of the worm;

Fig. 314, a detail of the
worm as used on a prom-
inent truck; and Fig. 315,
a detail of the spiral bevel
as used on a prominent
car.

Worm Gears. Prog-
ress in the application
of worm gears for rear-
axle use has been con-
siderable in the last few
years. In one respect,
at least, designers have
found it an advan-
tage. The top position
for the worm was not
much used at first, as it
was thought impossible
for it to receive sufficient
lubricant there. Conse-
quently, it was always
placed in the bottom posi-
tion, which cut down the
clearance considerably; in
this position the clearance
was less than with the

Fig. 315. Cadillac Helical-Bevel Driving Gear

and Pinion ordinary bevel. With the

proof that the worm could be lubricated in a satisfactory
manner in the top position, the majority of gears are so placed,
thus converting what was formerly a disadvantage into a,n
advantage, for in the upper position the clearance is greater
than with bevel gears. This is shown quite clearly in Fig. 312,

Digitized by VjOOQIC

GASOLINE AUTOMOBILES 433

where it will be noted that the worm-gear housing in the center
is actually higher than are the brake drums at either end of the axle.
This, too, despite the fact that a truss rod passes beneath the
center of the axle. For heavy trucks, especially, and for electric pleas-
ure cars, the worm has proved an ideal drive. In these situations,
there is the condition of high-engine or electric-motor speed, coupled
with low-vehicle speed requirements, which necessitate a considerable
reduction. As pointed out, the worm gives this in a small space.

For 1916, the very apparent tendency in final drives is toward
spiral bevels for pleasure cars and worms for electrics and trucks.
The tendency toward spirals is very great, amounting practically
to a landslide, 57 per cent using it against 10 for 1915. The devel-
opment of special machinery tot cutting these gears and the under-
standing of their use has brought this about. In the truck field
there has been a similar movement toward the worm, due to similar
causes.

Gear Pitch and Faces. The manufacturers of transmissions and
of gears for them do not agree as to the best gears. Neither do they
agree as to which gears are most quiet or most efficient. In general,
coarse-pitch stub-tooth gears are gaining faster than any other form.
The 6-8 pitch is fairly general for gears of f-inch and f-inch face,
and 4-5 pitch for wider gears. One manufacturer, Warner, con-
siders the finer pitch gears and narrower faces as less likely to make
noise, since they will not distort as much in hardening as wider gears.
In this, other manufacturers agree, but there are some who claim to
have had both quiet and noisy operation with both fine and coarse
pitch. The tendency toward compactness has not increased
transmission-gear faces any appreciable amount, nor has the
increased use of better steels and better hardening processes lessened
the size of the four noticeably.

Gear Troubles. Most of the common gear troubles have been
previously covered at the end of transmissions. There is not as
much trouble with gears today as there was several years ago. This
is due to better design, better materials, better processes, and better
assembling on the part of manufacturers and to more skill in handling,
caring for, and adjusting on the part of owners. Of course, the
repair man still finds plenty to do, but the percentage of gear repairs
is relatively less than ever before.

Digitized by

Google

434 GASOLINE AUTOMOBILES

SUMMARY OF INSTRUCTIONS
CLUTCHES

Q. Why is a clutch needed?

A. The clutch is needed to disconnect the rest of the drive
from the engine. The gasoline engine cannot start under a load but
must first get up speed. By means of the clutch, which can be
thrown out, the engine is allowed to run alone and get up the neces-
sary speed, then the load or drive can be thrown on. This is just as
true of the stationary gas engine as of the automobile, motor boat,
or aeroplane power plant.

Q. How does the clutch act?

A. It is designed and constructed so that the amount of friction
surface, with the spring pressure provided, is sufficient to transmit
the whole power of the engine (and slightly more as a factor of
safety) when the clutch is in. In addition, it is so designed and con-
structed that when the clutch is out the spring pressure is taken up
in such a way as to be self-contained, that is, its thrust is carried to
a member outside of the clutch itself which is able to withstand this
thrust. In this way, when the clutch is out, the engine is entirely
free, and when the clutch is in, the connection is such that it will
carry more than the maximum power of the engine.

Q. To what type of clutch does this apply?

A. This applies to all clutches, regardless of type or design,
with the single exception of clutches on traction engines or on agri-
cultural tractors. These are designed in the same way but work just
the opposite, being engaged only when the clutch pedal is pressed and
disengaged when it is released. On this account, the clutch is
arranged so that it can be set to be in all the time or out all the time.
With this exception, the arrangement described applies to all internal-
combustion engines, although clutches vary widely in type, size
and arrangement.

Q. What are some of the most popular forms of automobile
clutches?

A. The multiple-disc and the cone divide honors; and there are
a few expanding- and contracting-band forms and some miscellaneous
types. The first two included almost 94 per cent of the total in 1914,
over 95 in 1915, and almost 97 in 1916.

Digitized by

Google

GASOLINE AUTOMOBILES 435

Q. What are the two divisions of the cone form?

A. The cone form is made in two ways, the direct form and
the indirect form. The direct form has the cone introduced directly
into the flywheel, which is tapered inwards for this purpose. This
makes it a very simple device to construct, the machining of the fly-
wheel forming the female portion of the clutching surface. The indi-
rect form, or inverted cone, differs in that the female portion is made'
as a separate flange bolted to the flywheel and tapering outward.
The cone is placed inside of this, so that it works out against the
clutching surface instead of in against this surface, as in the direct type.

Q. What are the relative advantages of the two forms?

A. The indirect is little used now, although it was popular years
ago. The extra bolted-on inverted cone adds to the flywheel weight,
for it is large and heavy and gives considerable flywheel effect. How-
ever, the flywheel is simplified. The spring is enclosed between the
flywheel and the cone, this being considered an advantage in the early
days but now considered a disadvantage because it is inaccessible for
inspection or adjustment. The cone is pushed in — away from the
clutching surface — to disconnect it, while on the more simple direct
type, the cone is pushed out — away from the clutching surface — to
disconnect.

Q. What*are the divisions of the disc clutch?

A. Disc clutches are generally grouped according to lubrication,
those which run in oil being called wet, and those which run without
lubricant of any kind being called dry. In addition, a distinction is
generally made between the disc clutch with a very few plates (one,
two, or three), usually called a plate clutch, and the form with many
plates (10 or more) which is called a multiple-disc clutch. Either
plate or multiple form may run wet or dry.

Q. Explain the difference between the wet and dry multiple
forms.

A. In the wet form, the plates, or discs, are plain steel and are
submerged in oil, the entire clutch housing being filled with oil. The
clutch discs work steel face against steel face, the action of the spring
when the clutch is let in gradually squeezing out the oil from between
the faces. This gradual squeezing out of the oil gives this form its
gradual-application quality, for with six or seven pairs of discs the
squeezing-out process takes an appreciable length of time. In the

Digitized by

Google

436 GASOLINE AUTOMOBILES

dry form, the plates are ordinarily faced with a special clutching
surface of woven asbestos fabric similar to brake lining, this being
placed upon every alternate disc, that is, the actual clutching surfaces
consist of steel and fabric alternating. The general method of con-
struction is to take one set, say the inner discs, and face both sides of
each one. Then none of the outer discs are faced, so that when the
clutch is assembled there is a steel face against each fabric face. This
form is run absolutely dry; in fact, considerable pains is taken in
design and assembly to keep out any form of lubricant.

Q. Explain the difference between the plate and the multiple-
disc forms.

A. In the multiple-disc form, a considerable number, say 11, 13,
15, or some such number of discs, is used; the smaller number, as 5,
6, 7, etc., being the driving, and the larger half, as 8, 9, 10, etc., being
the driven. In the plate form, a very small number of plates of the
largest size which the flywheel will allow is used. As a rule, the fly-
wheel inner surface is machined out to form one of the surfaces, the
engaging or disengaging member another, and a single disc between;
or, perhaps, another large disc is fixed to the flywheel and two discs
used between this and the other two surfaces. The plate form has the
advantages of a small number of parts and of compactness; but, on
the other hand, the discs are so large and heavy that assembling is
not so easy and a considerable flywheel effect is produced. More-
over, it is not so easy to produce an absolutely flat surface in the
larger sizes, for which reason the clutching is not so even and smooth.
In the smaller sizes, no attempt is made at perfectly flat surfaces, as
the inequalities balance one another.

Q. What is the general tendency in cone-clutch surfaces?

A. As to size, the tendency is toward larger diameters and
smaller or narrowed clutch faces. As to materials, asbestos woven
fabric is gradually replacing leather. Light springs under the fabric
form the means of gradual engagement, corks going out with the
leather with which they were used.

Q. What is the general form of the clutch spring?

A. Formerly, all clutch springs were of spring wire of the maxi-
mum possible diameter and, therefore, very stiff. The modern
tendency is toward a distribution of spring pressure by means of a
number of smaller weaker springs. The former method almost invari-

Digitized by

Google

GASOLINE AUTOMOBILES 437

ably called for complete enclosure, making adjustments and replace-
ments difficult. The smaller springs are usually placed .outside,
so that they can be adjusted or replaced easily and quickly. It has
been found, tQo, that by using a large number, say 6, 7, or more,
distributed around the clutching surface, a much lighter spring pres-
sure can be used with equally good effect. In fact, many modern cars
have so light a clutch spring that it can be disengaged with one finger.

Q. How does the contracting-band clutch work?

A. It has two half-bands which the clutching mechanism draws
tight against a drum. In effect, a contracting-band clutch is like a
band brake, except that the braking band is in two halves and operates
from the center instead of from the exterior surface.

Q, Is this a popular form?

A. No. It is rapidly going out of use; only one or two American
cars, w r ith perhaps the same number in Europe, are now using it.

Q. How does the expanding-band clutch work?

A. In a somewhat similar manner to the expanding, or internal,
brake; that is, it has two segments of fairly stiff metal section, which
the movement of a cam, or expander, presses outward against the
inside of the clutch drum (or inside face of the flywheel). This cam,
or expander, is worked by the movement of the clutch pedal, or spring
— outward so as to expand the band and take hold of the drum for
engagement; inward so as to allow the band to contract.

Q. Is this type gaining in popularity?

A. No. On the contrary, it is losing so rapidly that there are
practically no cars built in this country with it, although a number
of old cars with this form are still running.

Q. What is the usual position of the clutch?

A. Within the flywheel. This saves a great deal of space, a
number of parts, and considerable weight.

Q. Why is this position used so freely?

A. Partly because of the savings just mentioned, and partly
because of the rapidly growing use of unit-power plants which forces
this location. With the engine and transmission as a unit and the
necessity for the clutch being between them, the flywheel interior is
about the only place for the clutch.

Q. How can the surface, and thus the transmitting power, of
clutch discs be increased?

Digitized by

Google

438 GASOLINE AUTOMOBILES

A. By the use of other than plane surfaces. Thus, in the Hele-
Shaw form each disc is made with a small cone projecting from it.
The outside of this engages with the interior of the cone on the next.
Other forms have half-cone or other inclined surfaces. and half-plane
surfaces. As a straight line is the shortest distance between two
points, so a plane flat surface gives the smallest area between any two
points in parallel surfaces. From this it is apparent that any surface
not plane offers a greater area than does the plane one. However,
the plane surface is so much easier and cheaper to make, use, replace,
etc., that it has gradually driven out all these forms with greater sur-
face despite their advantages in the way of transmitting power.

Q. What causes a slipping cone clutch?

A. A slipping cone clutch is generally caused by oil, grease, or
other lubricant on the clutching surface or by a weak spring.

Q. How can this be remedied?

A. The surface can be cleaned with kerosene, then with gaso-
line, and dried. Or, if the surface is glazed, it can be roughened by
using a file. Or, if the slipping occurs out on the road and no tools
are available, any powder or fine material which will give roughness
can be used. It is possible to get home with a slipping cone clutch
by de-clutching and forcing in some sand. Of course, this is not
advisable, but it works in an emergency.

Q. What causes a disc clutch to slip?

A. In a metal-to-metal type, a burred plate or a weak spring
or a very thin oil which can not all be squeezed out will prevent
engagement. The two latter causes are easily remedied; the former
means removing the clutch and taking it apart to find the plate which
is burred or roughened. In a faced, or dry disc, clutch slipping may
be caused by oil, grease, or other lubricant getting in on the surfaces
or by a weak spring.

Q. What other things may cause a clutch to slip?

A. The pedal may be held out, when it appears to be in, by the
emergency brake interlock, by a bent or twisted rod, by a rod which
presses against something, by a tight-fitting pin in one of the con-
nections, by a worn pin, or by a bent-clutch spider which cannot
contact all over because of this bend.
Questions for Home Study

1. Describe in detail the construction of the Studebaker clutch.

Digitized by VjOOQIC

GASOLINE AUTOMOBILES 439

2. Tell how you would adjust the Steams-Knight clutch springs.

3. Give the method of removing and replacing a clutch spring
in the Warner clutch.

4. If springs under the clutch facing of a cone clutch do not
produce gradual engagement, what is the matter, and how would you
remedy it?

5. How does the Cadillac clutch work?

6. How does it diff^ from other clutches of the same type?

7. How would you lubricate a clutch bearing, with what, and
how often?

8. Describe a quick, easy method of replacing corks in a clutch.

9. How would you construct a device to hold clutch springs
while replacing them?

TRANSMISSIONS

Q. What is the purpose of the transmission in a motor car?

A. To allow variations in the speed of the car forward from the
lowest to the highest, and for reverse, without varying the motor
speed greatly.

Q. Why cannot the engine speed be varied directly, doing
away with the transmission?

A. The lowest speed used in cars ordinarily would not be pos-
sible with the present engine, since it could not be throttled down
slow enough. Again, if the gearing were such as to give the present
lowest car speeds with the engine low speed, then for maximum engine
speeds the highest possible car speed would be very low. In short,
gearing is necess&ry to give a greater variation than is possible with
the engine alone. Further, reverse could not be obtained without
additional gears and this would necessitate also a method of shifting
the reverse gear into, and out of, mesh. Thus, all the requirements of
the modern gear transmission would be necessary for reverse alone.

Q. Show by the use of figures the impossibility of doing with-
out the transmission.

A. The circumference of 34-inch wheels is 136.8 inches, or 11 .4
feet. With the engine geared direct to the wheels, the speed of the
latter would be directly proportional to the former, considering the
gear reduction. If an average present-day gear reduction of 3.8 to 1
be considered. at 240 r.p.m., which is very low, the car would make

99 Digitized by

Google

440 GASOLINE AUTOMOBILES

10.3 m.p.h. as its lowest possible speed. And at 2400 r.p.m. — a high
maximum for an engine with as low a speed as 240 — the highest car
speed would be 103 m.p.h. As the average roads would not allow this
high a speed, and as the average car has a low speed approximating
3 m.p.h., it is apparent that the gear ratio is too high. By lowering
this to 12 to 1 at a low speed of 264 r.p.m. of the engine, a low car
speed of 2.S5 m.p.h. would be obtained. And with 2640 r.p.m. as the
highest engine speed, the highest car speed^vould be only 28.5 m.p.h.
From these two extremes, it is apparent that direct gearing without
a transmission is not feasible.

Q. What are the general classes of transmission now in use?

A. There are five general classes: sliding gear, individual clutch,
planetary, friction, and miscellaneous types. The first named is most
popular and constitutes perhaps 90 or more per cent of all the cars
now built. The individual clutch is really a modification of the slid-
ing gear, but is not widely used — not to exceed 3 or 4 per cent. The
planetary is the most simple form to operate but, unlike the others,
is limited as to the number of possible speeds. Practically the only
American maker using this today is Ford. The friction form w r as
intended to give a maximum number of speeds with maximum sim-
plicity. It does this, but other faults offset these advantages. Metz
is about the only American car-maker using it regularly. The mis-
cellaneous transmissions include what might be called the unproved
inventions — forms which have not been tried out sufficiently to be
proved successes. Consequently, this class is small. It includes
hydraulic, electric, magnetic, and variousother formsof transmissions.

Q. What is the average number of speeds?

A. Three is the most popular number, four is found on a number
of high-class cars, the planetary can give but two, the friction form
may give five or more, the only magnetic form on the market gives
seven. In general, three is considered sufficient; even the highest-
priced makers are gradually giving up the use of four-speed gear
boxes, and the number of these is less each year.

Q. What are the three methods of gear shifting now in use?

A. The selective accounts for about 94 per cent, the progressive
form is not used by more than 2 or 3, and electric shifting is used by
but two makers.

Q. How does the selective form work?

100

Digitized by

Google

GASOLINE AUTOMOBILES 441

A. The operator is at liberty to select any gear he desires and
to go directly to that speed from the speed which he is using. This
means with common sense reservations; for instance, it would be
foolish to go from high to reverse, although this is possible in this
form.

Q. How is this accomplished?

A. Within the gear box, the gears are shifted by forms, and the
quadrant arrangement is such that the driver can shift his lever so as
to pick up the fork which will give the desired speed. Usually there
are but two shifting members (in the three-speed form), one giving
low speed and reverse, the other intermediate and high. Having
picked up the low and reverse fork, he can shift his lever forward for
low and backward for reverse; similarly, with the other fork for
second and third speeds.

Q. How does the progressive form work?

A. In this type of gear box, the speeds must be used in succes-
sion — first the low, then second, then high, and when slowing down
from high, to second, then low, then reverse. For instance, if driving
in high and a turn is passed in a narrow road, it would be necessary
to shift down to second, then to low, then to reverse. The driver
could now back his car past the street into a position which would
enable him to make the turn. Then he could speed up the car again
by using first low speed, then second, and finally high. This maneu-
ver could not be accomplished in any other way. In the same cir-
cumstances with a selective gear, the car could be brought to a dead
stop with the brakes, an immediate shift to reverse effected, the car
backed up, and the gears shifted to low and then high speed forward,
thus doing the same thing as before with half as many changes.

Q. How is the high speed generally effected?

A. High speed in all modern transmissions is a direct drive so
that none of the various gear reductions are in use. This method
reduces the amount of noise by eliminating at once the meshing of
two sets of gears, the average high-speed direct drive being effected
by clutching one gear up to another.

Q. Is this arrangement always used?

A. No. In some four-speed gears the highest speed is a geared-
up form, and the direct drive is used on third speed. This is done with
the idea of securing the silence of the direct drive for all average

Digitized by

Google

442 GASOLINE AUTOMOBILES

rapid driving, while the geared-up form gives an extraordinary speed
for emergencies where noise is immaterial.

Q. In the electric gear shifter, how is the movement of gears
effected?

A. The shifter is made with a series of electromagnets, or sole-
noids, one for each speed and one for reverse. Current flows to these
when the proper button is pressed. It is well known that when an
electric current is passed through an electromagnet of the solenoid
type, the rod, or bar, inside of it is drawn forward. This arrangement
produces the speed corresponding to the button pressed. In actual
practice, the current does not flow until the clutch pedal is depressed
after the button has been pressed.

Q. Where is the transmission located?

A. Excluding freak forms, there are four general positions: in
unit with the motor; amidships in unit with the clutch; amidships
but separated from the clutch and in unit with the forward end of the
driving shaft; and in unit with the rear axle.

Q. Are these same locations used on motor trucks?

A. Yes. Except that the third class is sometimes modified with
chain drive, so that the transmission is amidships but in unit with
the jackshaft.

Q. Which of these is most popular?

A. The form in which the transmission is grouped with the
motor and clutch, that is, the unit power plant, is now the most
popular, and the tendency among the makers is to make it more so.
It is gaining at the expense of all other locations.

Q. What difference is noted in gasoline railway-car trans-
missions?

A. As all speeds must be used in the reverse direction, the design
is so modified as to allow the driver first to choose the direction and
then to utilize all his transmission speeds in that direction.

Q. What is the difference between individual clutch and other
transmissions, particularly the sliding-gear type?

A. In the individual-clutch type, no one of the gears is fixed to
its shaft, but an individual clutch is provided for each. The purpose
of this is to clutch the gear to its shaft so that it can drive or be
driven. When shifting gears, the driver moves the usual lever in the
usual way, but within the transmission this lever, instead of moving

102

Digitized by

Google

GASOLINE AUTOMOBILES 443

a gear on a shaft to which it is keyed, moves a clutch which keys the
desired gear to the shaft.

Q. What is the advantage of this over sliding gears?

A. In the sliding gear, the moving members must take the drive
and transmit the power in addition to withstanding the shocks and
destructive action of shifting or meshing. In the individual clutch
form, the gears have only to transmit the power, while the individual
clutches have only the shocks and destructive action of shifting.

Q. How are gears pressed onto their shafts?

A. Usually by means of a hydraulic or a power press — one
capable of exerting a pressure of many tons. Generally, it is easier
to lay the gear out on the press table and press the shaft down into
it, than the reverse.

Q. How are pressed-on gears removed?

A. The process of pressing on is reversed, and the gear is sup-
ported in such a way that the shaft can be pressed, or forced, out of it.

Q. How is the transmission removed from the chassis?

A. The usual method in well-equipped shops is to put a rope
or chain sling or special cradle around the transmission, then to lift
it vertically upwards by means of a block and tackle, electric or pneu-
matic overhead hoist, chain block attached to overhead tracks, or
portable crane.

Q. How are bearings worked in?

A. After slow careful fitting by hand for both diameter and
length, using a dummy shaft with dummy bearings, the real bearings
should be put in place and run-in for several hours, using power from
a line shaft. Transmission bearings should be run-in the same as
engine bearings, set up somewhat tight and with an excess of oil.
Questions for Home Study

1. Describe the construction of the Cadillac and Winton trans-
missions, a railway transmission, the Mack truck, the Ford planetary,
a friction form, and a magnetic type.

2. How would you adjust the shafts longitudinally in the
Stearns transmission?

3. Tell how to construct a stand for gear pressing.

4. Give a thorough method of cleaning a transmission.

5. What are the usual gear pitches?

6. What is meant by the pitch of a gear?

103

1
1

Digitized by

GooQle

GASOLINE AUTOMOBILES

PART V

STEERING GROUP

The mechanisms by which steering is effected are among the
most important features of a car, if not actually the most important.
The truth of this statement will be realized when attention is called
to the fact that safe steering is the final requisite that has made the
modern high speeds possible, for without safe and dependable steering
gears, no racing driver would dare to run a machine at a high rate of
speed, knowing that at any minute the unsafe steering apparatus
might shift the control, thus allowing the front wheels to waver and
the car to run into some obstruction by the roadside.

The same argument applies in an even greater degree to the
case of the non-professional driver, who wants to be on the safe side
even more, perhaps, than do the dare-devils who drive racing cars.
Nearly all of our roads are curved and, to make all of these turns
with safety, the steering gear must be reliable. Again, in mountain-
ous country where there may be a sheer drop at the roadside of
hundreds of feet, it becomes necessary that the steering mechanism
be very accurate and that it obey, at once, the slightest move
on the driver's part. To secure this accuracy, there must be no lost
motion or wear of the interrelated parts.

These things mean that the whole steering mechanism must be
safe and reliable; strong and accurate; well made and carefully fitted;
well cared for; and finally, the design and construction must* be
based on a theoretically correct principle, for otherwise the mechanical
refinements will have been wasted. Perhaps it will be more logical
to treat the mechanical requirements first by showing how the
present type has been evolved from the failures of earlier forms.

STEERING QEARS
General Requirements. In turning a corner a car follows a
curve, the outer wheels obviously following curves of longer radius
than do the inner wheels and, therefore, traveling farther. In

105

Digitized by

Google

446 GASOLINE AUTOMOBILES

straight-ahead running, the wheels run parallel at all times and
travel the same distance. These two facts are the basic ones which
make the steering action so complicated: First, that on straight-
ahead running the wheels must travel the same distance; and second,
that on turning curves the outer wheels, whichever they may be,
must travel a greater distance.

This double requirement leads to the usual form of steering
arrangement, called after its inventor, the "Ackerman". It was
Ackerman who brought out the first vehicle in which the front
wheels were mounted upon pivoted-axle ends, these ends being pivoted
on the extremities of the central part of a fixed axle, while the pivoted
ends carried one lever each. These levers were connected together
by means of a cross-rod, while at one end another rod was attached,
which was used to move the wheels. By moving this latter rod,
both wheels were compelled to turn about their pivot points, since
the cross-rod joined them together, and if one moved the other had
to move also. This was Ackerman's substitute for the fifth wheel
which had been used up to that time and is even today on all horse-
drawn vehicles.

Inclining Axle Pivots. The situation is further complicated
by the fact that the ideal arrangement, that is, the fixing of the steer-
ing pivot at the center of the turning wheel in order to allow the maxi-
mum turning movement for the minimum motion of the hand, is not
suitable for general use. In practice, however, it is placed as close
to the ideal position as possible, which, in the ordinary case, is within
three to six inches.

This approximation to the ideal has been made by inclining the
stud-axle pivot inward, so that its center line prolonged would strike
the ground at a point coincident with the center line of the tire. This
same result is also brought about by inclining the stud axle itself
downward. The construction give^ added safety, in that the force
of head-on collisions is supposed to be delivered at or near the line
of incidence.

The axle-spindle center may be brought close to the wheel hub
by means of a double yoke, but this was tried and abandoned as
too cumbersome for the results effected. A method of placing the
steering pivot in the center of the wheel was also developed. In this
case the pivot was enclosed in a hollow hub; but as this made ths

106

Digitized by

Google

GASOLINE AUTOMOBILES 447

pivot, which is liable to wear, inaccessible, it also was abandoned.
However, later tendencies point toward a revival of this construction*
The result is that today we are using a form which, though far
from being ideal, fulfills every practical requirement. This form is
usually constructed as in Fig. 316, which shows a skeleton plan view
of an automobile. In this, the line AB represents in length, posi-
tion, and direction, the front axle of a car, while ML represents
in a similar manner the rear axle. A and B also are the pivot points
for the axle-stud ends or, as they are more commonly called, the

Fig. 316. Diagram of Steering Connections

steering knuckles or steering pivots, which are represented by the
lines AD and BC.

The rear (or front, as the case may be) ends of the steering
knuckles are joined by the connecting rod DC. The Ackerman con-
struction is such that the center lines of the steering arms, or levers,
AD and BC 9 prolonged, must pass through the center point of the
rear axle at K; the reason for this is that the front wheels are sup-
posed to turn about the center of the rear axle as a center.

Action of Wheels in Turning. If the wheels are supposed to
turn through an angle, the action of the above arrangement will be
seen. Suppose the steering gear (not shown in Fig. 316) is turned ao
as to move the steering lever AD to the new position, shown dotted
at AD i. This m6vement will also move the other lever BC to a new
position, shown dotted at BC\. It will be noted in this position that
the angle through which the right-hand lever BC has swung is not as

107

Digitized by

Google

448 GASOLINE AUTOMOBILES

great as that through which the left-hand lever AD has moved,
although the two levers are attached together by means of the cross-
connection DC.

The wheels are mounted upon the extremities of the steering
knuckles at F and /; EG represents the left wheel, and HJ the
right wheel. These turn about the pivot points A and B, with
the movement of the steering knuckles to the new position, shown
dotted at E1F1G1 and H1I1J1. In this position, prolongations
of the lines through the pivot point and the center of the two
wheels will meet the rear-axle center line prolonged at separate
points as OP, the two lines converging slightly. This same con-
vergence may be noted by prolonging the center line of the two
wheels EiGi to Q and #i«/i to R. This divergence means that
the two wheels are turning on curves of different radii, and since the
outer wheel HiJi shows a longer distance from its center line pro-
longed to the rear-axle line OPM KL than does the inner wheel,
that is, has the longer false radius, PI\ being longer than OFi, it
follows that the turning action will be correct.

This is somewhat complicated and rather hard to follow, but
the figure seems simple and should be examined closely, even draw-
ing it out step by step, as outlined above, for the purpose of making
the steering action clear. Laying this out for one's self will bring
out the reason why the steering knuckles do not move through the
same distance and thus bring about a different movement of the
wheels.

Steering Levers in Front of Axle. That the final movement
of the wheels will not be changed if the levers, Fig. 316, are laid out
in the same way but in front of the axle will be evident by prolong-
ing the levers to S and T, respectively, making the lengths AS
and BT the same as the former lengths AD and BC. Connecting
the two by the rod ST completes the front arrangement, which is
seen to give the same results as the other. The choice of a front or
rear location depends upon certain things, such as the safety of the
cross-rod, etc., which will be brought out later on. Some machine
manufacturers even go so far as to fit both front and rear levers to
the same machine.

While shifting the lever from rear to front in Fig. 316 does not
change the result at all, in Fig. 317 it does. In this construction,

108

Digitized by VjOOQlC

GASOLINE AUTOMOBILES

449

known as the Davis, the steering levers aie set in front, but taper
inward instead of outward, so that their center lines prolonged
meet the center line of the car prolonged at a distance from the front
axle equal to the distance between the front and rear axles, or equal
to the wheel base.

In addition, the connecting rod is carried in guides placed on
the front of the axle, so that its path of travel is always parallel to
the front axle. Consequently, the levers .must be made slotted or
telescopic. The result of this combination of movements is an

\\
V

** x

p A

l L

Fig. 317. Patented English Steering Device, Said to be Theoretically Perfect

absolutely Correct angle to both wheels for any angle of lock. This
can be explained by a reference to the diagram.

In Fig. 316 the prolongations of the wheel center lines, or radii of
turning, do not strike the center line of the rear axle — about which
they are supposed to turn— at a common point, the difference being
the amount they are out of true, viz, the distance between the points
O and P. If Fig. 317 be lettered to correspond with Fig. 310, the
prolongations of the knuckle center lines AF\0 and lJiP in
Fig. 316 become the two converging lines AFiO and 1\B0 meeting

109

Digitized by

Google

450 GASOLINE AUTOMOBILES

at the point on the center line LMO of the rear axle prolonged.
This is as it should be and shows the case of correct steering and
turning.

In this case, all four wheels are turning about the point 0, the
two rear wheels with the radii OM and OL, and the two front wheels
with the radii OFi and 01 u respectively. This gives a theoretically
correct case in which all wheels will round any curve as they should
and not slip or slide around, damaging the tires in the process. The
Davis type of steering gear, it may be remarked, is not in general
use, its construction adding a number of parts to the more usual form,
shown in Fig. 316, which gives close enough results for average use.

Like the sliding-gear transmission, a steering gear is a form of
mechanism which, although used on nearly all automobiles, is, from
a theoretical and mechanical standpoint, far from what it should be.

General Characteristics of Steering Gears. Standard Types.
The movement or deflection of the front road wheels is obtained bv

Fig. 318. Typical Steering Gear and Connections to Front Axle

a crosswise movement of the tie rod which links the steering-knuckle
levers attached to the wheels. This tie rod, sometimes referred to as
the cross-connecting rod, is actuated by the drag link GF, Fig. 318,
which is pivotally mounted on the steering-knuckle lever L. The
drag link has a linear movement along the frame and is parallel with it.
The drag link is also pivotally mounted at the ball arm of the
steering gear C, and when the drag link is moved forward or back-
ward by movement of the ball arm, the tie rod is moved at right
angles, deflecting the wheels. The drag link has a semi-rotary
motion; that is, its upper end is turned through a part of a revolu-
tion while it^ lower end, to which the drag link is attached, swings

Digitized by

Google

GASOLINE AUTOMOBILES

451

through a fairly large arc, according to the capacity and design of
the steering gear.

As the ball arm swings through its arc, the drag link attached to
it rises and falls slightly, the movement being indicated by the dotted
lines in Fig. 318. The partial circular motion in a vertical plane is
converted from the rotation of the steering gear in a horizontal plane
by several methods. The gear shown in Fig. 319 is known as the
worm and sector type, which is illustrated in Fig. 318.

In Fig. 319 the steering column or post CD carries a worm F
which is in mesh with the gear E.
Rotating the column CD in the
direction indicated by the arrows,
or counter-clockwise, will result
in the worm turning in the same
direction. The gear E will rotate
on its horizontal shaft in a down-
ward movement, as shown by the
arrow, and as the ball arm, or
lever, fe attached to the shaft, the
member L will move backward,
or to the left, as shown by the
arrow intersecting the ball. With
the worm type the two gears are
usually in two different planes
at right angles to each other, one
vertical and the other horizontal.
This is an advantage in that it
lends itself readily to the con-
struction of a simple steering-
gear system. Thus the post is in a vertical or modified vertical line,
as is also the motion of the steering arm, and the consequent
movement of the steering rod is more or less confined to a vertical
plane. With the worm and gear this is obtained in a simple manner.
The gearshaft is in a horizontal plane passing through the center line
of the worm. If the worm rotates in a direction which approxi-
mates a horizontal circle around a vertical axis, the worm gear will
turn in a vertical plane about a horizontal axis. A lever attached
to the end of this shaft will, consequently, move in the desired

Fig. 319.

Worm and Partial Gear of Typical
Steering Gear

111

Digitized by

Google

452 GASOLINE AUTOMOBILES

plane — the vertical one mentioned before — and the desired require-
ments are met.

The conversion of rotary motion in a horizontal plane to partial
rotation in a vertical plane is shown in Fig. 320, the action here being
slightly amplified. The steering, or hand, wheel A with spokes B is
turned to the left, turning the steering column C (a hollow tube) in
the direction indicated by the small arrow. D is the steering gear
with its ball arm E. The turning of the hand wheel moves the
ball end F and drag link backward. The front end of the drag link
is attached to the steering knuckle M at H and turns about the
center line KL of the steering knuckle J, the end turning through

Fig. 320. Steering Mcchan.sai an J Front Axle of Pierce- Arrow Car
Courtesy of Pierce-Arrow Motor Car Company, Buffalo, New York

the arc HI. The lever M is attached to the knuckle J and turns with
it. Its end turns through the arc 0P t moving the tie rod OQ to the
right and turning the other knuckle in the same way and direction.
Y Y are the spring pads and ZZ the tapered roller bearings support-
ing the road wheels.

Classification. There are three general forms of steering gears:
the worm, the bevel, and the spur. These may be subdivided,
which might lead one to assume that there are a dozen or more
different forms. The mechanical lever has been discarded because of
its tendency to impart all road shocks to the driver; it is fully revers-
ible at all times. Irreversibility is employed because it transmits to

112

Digitized by

Google

GASOLINE AUTOMOBILES

453

the road wheels any turning movement imparted by the driver
without reversing or carrying back to the operator the original move-
ment of the road wheels.

Many attempts have been made to substitute another form of
mechanism for steering gears; this consists of various rod, lever,
chain, and spring combinations. All of these have failed, however,
because they lacked the
fundamental reauisite of
irreversibility.

Aside from the many
schemes mentioned which
seek to avoid the use of
the regular gear in the
standard manner, there
have been a number of
unsuccessful attempts to
avoid its use in other
ways. Fig. 321 shows
some of the gears which
have been tried. At 1 is
seen a device in which the
rotation of a large bevel
gear turned a small bevel
pinion, the rotation of the
latter serving to screw a
long straight lever with a
threaded inner end into or
out of the interior of the
threaded bevel pinion.

In the figure, N is the
actuating bevel turned by
the movement of the operator's hands, while is the smaller actu-
ated bevel pinion. Within this is seen the worm end S of the
lever J f the ball at the outer end being connected to the steering
knuckle. Since the bevel alone lost a great deal of power in friction,
while the worm arrangement and the sliding action of the lever in
its bearings did likewise, the total effort to turn this must have been
enormous. At 2 is shown another form, which is the double-bevel

Fig. 321. Obsolete Forma of Worm Steering Gears

113

Digitized by

Google

454 GASOLINE AUTOMOBILES

arrangement; a small bevel N attached to the steering post K turns
the larger bevel 0, which is pivoted at the axis M about which the
lever J attached to the segmental bevel turns.

A most peculiar arrangement is shown at 3, this being a com-
bination of a wonp and nut, two levers and a steering arm, as well
as a connecting link for the two levers. Turning the hand wheel
turns the worm, which moves the nut up or down. Since the nut
is connected by means of the link to the lever, the motion of the
nut up and down is transmitted to the short lever; this, in turn,
moves the long-arm, or steering, lever. In the figure, K is the steering
post, N the worm, the nut, P the connecting link pivoted at the
two ends T and S, Q the short-arm lever, and J the steering lever,
the two latter being integral and pivoted at the point R. At 4
is shown a combination of a double internal worm with a rack and
gear. In this, the turning movement of the inner worm causes the
outer worm to travel up and down. Upon the exterior of this outer
worm is cut a rack which is meshed with the gear, its up and down
movements turning the gear around and thus effecting the steering,
the steering lever being attached to the gear. N is the internal
worm, the external worm with the exterior rack, P the gear which
meshes with it and carries the lever J as a part of it. At 5 is shown
a combination of a double worm with a double ball and socket
arrangement. The turning of the outer worm iV\ causes the inner
worm N to rise and fall, the lower end of this carrying a ball-and-
socket joint 0, the end of the ball being formed integral with the
steering lever J, which also has a ball and socket attachment at the
other end. At 6 is shown a steering gear which was tried and dis-
carded, but which is now coming to the fore and bids fair to oust
many other forms of gear. It is variously called a globular worm,
helicoidal worm, or Hindley worm, the worm forming a curve closely
approximating the curve of the gear with which it is to mesh. This
gives a greater number of teeth in mesh at any one time, spreading
the wear over a larger surface and thus lengthening the life as well as
accuracy of the steering gear.

Spur and Bevel Types. The spur- and bevel-toothed construc-
tion of gears may be reversible, and these types are to be found on
low-priced cars, as the cost of cutting the gears is small. The spur
gears have straight teeth, the edges, or sides, of the teeth being straight

114

Digitized by

Google

GASOLINE AUTOMOBILES 455

and parallel with the axis of the shaft on which the gear turns. In
bevel gears the teeth taper toward a point and are inclined to the
axis of the shaft. Another construction is the spiral gear. Both
types may be made reversible and irreversible as desired.

Worm-Gear Types. With a very few exceptions, automobile
engineers favor the worm type of steering gear, and it will be found
on the highest priced cars. It has the advantage of being irreversible
and is utilized in several forms. In the worm class of gears, some types
are closely related, while others vary widely. For example, the com-
plete sector and gear type
differ only in that the wheel
operated by the worm makes
a complete circle or part of
a circle. The full gear can
be turned through 90 degrees
and replaced on the shaft
without presenting a new
surface to the worm. Some
hold that the worm must be
subject to some wear, espe-
cially where it is most used.
They contend that turning
over the pinion brings new
teeth to engage with the
worm and that these teeth
will not mesh properly when
turned at an angle of from
20 to 30 degrees. Fig - 322 ' Wor ££&?££ x Gear Type *

Worm and Partial Gear.
Fig. 322 illustrates a gear of the worm and partial gear type.
Advantages claimed for the design are durability, ease of action,
and adjustability to wear. The parts are accurately cut and hard-
ened, and the worm is provided with a ball thrust on either side.
With this type, the teeth, which are in the middle of the sector
and in mesh, perform the greatest work when the car is driven in
a straight line and are most susceptible to wear. To compensate
for this wear, the center teeth are cut on a slightly less pitch radius
so that lost^ motion may be eliminated without affecting the upper

115

Digitized by

Google

456 GASOLINE AUTOMOBILES

and lower teeth of the sector and to prevent binding when turning
at right angles. In the illustration, A is the steering column to
which the worm C is secured, D is the sector in mesh with the
worm, E is the ball arm, or lever, B the gear housing, F the spark
and throttle bevel gears and levers, and G the lubricant plug.

Adjustment. Two principal adjustments are provided. End
play of the worm is eliminated by loosening the jamb nuts and lock
screws on the column housing. Displacing the oil plug G will dis-
close an adjusting collar which is set with a screwdriver. Adjust
collar until all play is eliminated, but the worm must turn easily.
The lock screws, above referred to, are so located in the gear housing
that when one is directly over a slot in the adjusting collar the other
is between two slots. Consequently, after adjusting the collar it is
essential that the proper screw be selected for locking the adjustment.
Both locking members must be prevented from turning, by using the
nuts. Wear of the teeth of the worm and sector may be eliminated
by means of an eccentric bushing, which, when turned, moves the
sectoi*into a closer relation with the worm. This is accomplished by
removing a locking screw at the left of the ball arm and moving
the arm, which turns the eccentric bushing. In case of extreme wear,
it may be necessary to displace the ball arm and set the locking-screw
section in a different position on the end of the hexagonal end of the
eccentric bushing so as to bring the arm in such a position that it can
be locked by the screw. End play of the sector shaft is eliminated
by removing a locking arm and turning an adjusting screw in, after
which the arm and lock screw are replaced and both set up tight.

Worm and Full Gear. A full gear and worm type of steering
gear is shown in Fig. 323, with jthe gear cover removed. This type
is irreversible, and the advantage claimed for it is that it can be easily
removed and so readjusted that an unworn section of the gear may
be brought into contact with the worm. This is a simple form, and
it is possible to replace a worn gear with a new one, as the gears are
not expensive.

Fig. 324 shows a much more complicated form of worm and full
gear in which the inventor has attempted to gain something by
the use of a double steering gear, that is, two complete sets of worms
and gears set opposing one another, the gears being made to mesh
with each other just like a pair of spur gears. Since the lever can

116

Digitized by CjOOQIC

GASOLINE AUTOMOBILES 457

be attached to but one of the turning gears, the other gear with
its actuating worm is useless. The inventor doubtless intended
the two worms to oppose each other and thus be self-sustaining as
to thrust, but such would not be the case, the actual thrust being in
opposite directions in the two cases of the upper and low r er worms,
the total thus being double the usual amount.

Adjustment. The part most subject to wear is that section of
the gear which meshes with the w T orm when the front wheels are
traveling in approximately a straight line. Because of this wear, the
teeth of the wheel are subject to deterioration. Usually the adjust-

Fig. 323. Typical Worm and Full Gear Steering Device

ment for the wear is made by bringing the worm into a closer relation-
ship with the gear by using the eccentric bushings which support the
worm shaft. This adjustment is practical when the lost motion is
due to poor adjustment rather than to wear of the teeth. With the
majority of types, it is possible to displace the steering arms, move
the steering wheel about half a turn, then replace the worm wheel so
that an unworn section opposite the worn teeth will be brought into
engagement with a comparatively unworn portion of the worm
proper. The eccentric bushings in this case can be utilized to obtain
a correct meshing of the worm and gear teeth. End play of the worm

117

Digitized by

Google

458

GASOLINE AUTOMOBILES

can be removed by adjusting the ball thrust bearings on either sicfe
of the worm. Sometimes these bearings become dry, or the lubri-
cant becomes gummy, causing the shaft to turn hard. Wear of plain
bushings in the steering-gear case is responsible for lost motion; the
remedy is to replace the bushings with new members.

Warm and Nut, Next to the worm and gear, either full or
partial, the form of steering gear most used is the worm and nut,
which is made in several different combinations. Thus, the nut may
operate the steering lever directly through the medium of a secondary
lever, or it may actuate a block, which, in turn, moves either the
lever direct or the secondary lever. In Fig. 325 another form of

Fig. 324. Double Worm and Gear
Steering Device

Fig. 325. Worm and Nut Steering
Device

the worm and nut variety is shown. This has a nut which the turning
of the worm moves up and down but which is split, the two halves
being bolted together. A spherical seat is formed in the two
halves of the split nut into which a ball-end lever is set, the bolt
serving to clamp the two pieces together and hold the lever there.
This is the end of the secondary lever, which is connected by
means of another lever to the steering lever itself. In the figure, A
is the worm, B and Bi the two parts of the nut, C the clamping
bolt, and D the hinge at the other end. E and E\ represent the
spherical seats for the ball end of the other lever.

218

Digitized by

Google

GASOLINE AUTOMOBILES 459

Having the nut in two widely separated parts reduces the wear
on each, since the bearing surface is spread out more than would be

JttAB Vtew \ I S/de View

Fig. 326. Steering Gear Used on Heavy Manhattan Trucks

the case with an uncut nut. In addition, the split nut allows the
changing of the ball-end lever at any and all times.

Digitized by

Google

460

GASOLINE AUTOMOBILES

Fig. 327. Sectional Details of Steering

Gear of Winton Care

Winton Motor Car Company,

Cleveland, Ohio

In Fig. 326 is shown a form of
worm and nut steering gear which is
used on very heavy trucks and com-
merical cars. In this gear, the double
worm is used; the inner worm carries,
at its lower end, a block which is piv-
oted in a combination lever and shaft,
to which the steering arm is attached.
In the figure, A is the hand wheel
turning the rod B within the steering-
post tube C. This rod is driven into
and keyed at its lower end to a mem-
ber D which has internal worm
threads. Another member E has a
circular upper end on which are worm
threads, while its lower end is slotted.
The worm at the upper end meshes
with the internal worm threads in
piece D, while the lower slotted end
carries, between the two arms of the
slot, a rectangular block F. This
block is hardened and ground all over
and is fastened to the forked end of
piece E by means of the hardened and
ground pin G. This pin also passes
through the arm H of the shaft to
which the steering arm is attached.
The steering arm is free to rotate
about the center. This rotation moves
the steering lever L in the arm of >
circle.

The steering action is as follows:
Turning the hand wheel turns the
outer worm. This worm cannot move,
so the inner worm is forced to move
up or down, as the case may be, and
moves the block with the pin through
it, which, being fixed in the arm

120

Digitized by

Google

GASOLINE AUTOMOBILES 461

extension of the shaft, must turn the shaft. To this arm is attached
the steering lever, so the latter must move. Although a rather com-
plicated gear to explain and also to make, this gear, when finished, is
an excellent one, and has been used for five or six years on heavy
trucks with excellent results.

The Winton steering gear, Fig. 327, is not decidedly different
from the one just shown, as will be noted by a close inspection of the
parts. A is the internal worm, which is turned by the hand wheel,
while engaging this worm are the block B and pin C, the block being
partly cut away to show the engaging gear teeth. This block moves
the jaw arm of the steering lever D. This jaw is not complete in
this gear, but is cut away to save weight. The jaw arm, too, is con-
nected directly with the steering lever, the jaw, arm, and shaft making
one piece. The light work to which this was put made possible the
economy in the number of pieces and in the weight of each. As
before, turning the hand wheel turns the worm, which, in turn, moves
the block and pin up and down and thus moves the jaw arm, which
moves the steering lever.

Adjustment. The adjustment for lost motion in the worm and
split-nut type of gear is generally made by loosening a cap screw on
the column and screwing down an adjusting nut which has a right-
hand thread. This adjusting nut acts directly on the thrust bearing,
forcing the screw and half nuts, which slide, against the yoke rollers.
In making the adjustment to a gear of this type, it is advisable to
turn the road wheels to the extreme angle position, because the gear
is the least worn at this point, and if it is adjusted only enough to
take up the play when in this position, there will be danger of binding.
Sometimes, when the adjustment is made with the road wheels straight,
the gear will bind at the extreme positions.

Warm and Worm. In the worm and worm form of steering gear
there is a worm within a worm, not wholly unlike the ones just
described. Fig. 328 shows an example of this, which has a worm C
attached to the steering rod H , which is turned by the steering wheel
A. Within and without this are worm threads, an external worm
B meshing with the internal worm on the inside of C, while an internal
worm D meshes with the external worm on C. The action of turn-
ing the hand wheel, then, moves one of these upward and the other
downward.

121

Digitized by

Google

4W GASOLINE AUTOMOBILES

The lower end Bi of the inner worm member presses against
a hardened end of the steering-lever arm E, while the lower end D\
of the outer worm member presses against the other hardened end
E\ of the same piece. There is no lost motion, or play, in the gear;
when the hand wheel is turned, one worm rises and the other falls,
as just described; the piece E will let one end rise and the other fall,
as it is acted upon by the lower extremities of the two moving worms.
This piece is pivoted at F and carries at its outer end the steering
lever G, which thus moves in the customary manner. Within the
steering post are the spark and throttle fube and rod / and J, which

Fig. 328. Section of Gemmer Steering Gear
Courtesy of Gemmer Occur Company, Detroit, Michigan

carry right through the whole gear and out at the bottom, where
the spark and throttle-actuating levers are attached.

Adjustment. The adjustment of the worm and worm type, an
example of which is illustrated in Fig. 328, is generally effected by a
nut located at the upper end of the gear housing. This nut is pro-
vided with flats to accommodate a wrench hold. The end of the
worm-wheel shaft is squared, and to this square the steering-lever
arms are attached by means of a pinch clamp and bolt.

Bevel Pinion and Sector. Among the other types of steering
gears is that of the bevel pinion and sector, shown in Fig. 329. The

122

Digitized by VjOOQ IC

GASOLINE AUTOMOBILES

463

bevel pinion moves the bevel-gear sector back and forth as it is turned,
this motion being transferred to the steering arm attached on the
same shaft to which the bevel sector is secured. This type of gear is
said to be effective, but it is not irreversible, and shocks to the road
wheels may be imparted to the steering wheel and move it.

Flf . 329. Bevel Pinion and Sector Type of Steering Gear
Courtesy of Reo Motor Car Company, Lansing, Michigan

Adjustment. The bevel and sector gear has two adjustments.
The pinion may be moved up or down, as required, by unlocking the
clamp bolts (one of which is shown at D) which permits the moving of
the entire steering column up or down so as to obtain the proper

12s

Digitized by

Google

464

GASOLINE AUTOMOBILES

relative position to the pinion and its sector. The position of the
sector endwise may be adjusted by the block member A, which bears
against a roller guide, forcing the sector into mesh more or less closely
with the pinion. The spring E is provided to prevent rattling, and
the* screw H is a guide for the plunger and should not be disturbed
in making the adjustment.

Hindley Worm Gear. There are a number of things about the
Hindley type of worm which make it an excellent one to use for
steering gears. A realization of this advantage is bringing about a
greatly increased use of this form; so it will be appropriate and timely

to look into its form, con-
struction, and advantages.

The question of what
makes the Hindley different
from other worms naturally
arises. The ordinary worm
has the same diameter from
one end to the other, the
blank before the cutting of
the teeth resembling a sec-
tion of a cylinder. The Hind-
ley, on the other hand, is not
of uniform diameter, but has
a smaller center diameter and
enlarged ends. This gives it

Fig. 330. Details of the Hindley Worm ft ^^ Qr hour . glass> shape .

An illustration will make this clear. Fig. 330 shows at A how
the Hindley shape is generated and at B a finished gear, revealing
plainly the reduced center diameter. In the upper figure, EE is the
center line, or axis, of the worm, and the center of the gear which
is to mesh with it. CD is a circular arc struck from as a center.
If, on this curve CD, equal spaces be struck off, using a distance equal
to the pitch of a single-threaded worm or the lead of a multiple-
threaded one, as at F, and radial lines be drawn from the center
to these points, these lines will be normal to the surface of the worm at
those points; in short, the worm must pass through them, as roughly
sketched in the figure. In the lower part B, of the figure, is illustrated
a worm made on this principle, ready to be put into position.

124

Digitized by

Google

GASOLINE AUTOMOBILES 465

This form of worm is used for the double reason of presenting
more wearing surface — since it has at least three teeth in contact
at any one time, as compared with one or at most two in the
ordinary worm — and greater resistance to reversibility. The worm
is used for steering gears because it is partly or wholly irreversible,
its motion being a sliding one; nevertheless, all worms may be
so cut as to be either wholly or not at all reversible. The sliding
motion of the two parts in contact, as opposed to the rolling motion
in the case of other mechanical movements of a similar nature, is
greatly increased if there are three teeth in contact instead of the
more usual one. If the friction of sliding be increased, the amount
of reversibility will be decreased in the same proportion, for the added
sliding friction will increase the natural reluctance of the worm to
transmit power backwards. So much is this the case that it pays
to use the Hindley form, despite its greatly increased cost of cutting.

Ford Steering Gear. The steering mechanism of the Ford car —
a patented construction — differs radically from the conventional
types in that its hand wheel does not directly rotate, or turn, the steer-
ing column or rod, but it imparts the necessary turning movement
through the gearing and the use of a small shaft to which the hand
wheel is attached. A phantom view of the gearing is shown in Fig. 331 .

The steering column with its short shaft and drive pinion is
enclosed in a tube or housing which is set at an angle and bolted to
the dash. The housing does not extend the entire length of the
column, as the lower end of it is mounted in a bracket that is rigidly
bolted to the frame. The steering-gear post, or column, has a tri-
angular flange at right angles to the rod, and each point of the flange
has an integral stub, or pin, carrying a small spur pinion. The center
of the rod is drilled and bushed to take a small shaft to which a fourth
pinion, or drive pinion, is keyed. The upper part of the housing is
shaped so as to provide a gear case, and the inner periphery of this
case is cut to obtain spur teeth or, in other words, an internal ring
gear. This gear is stationary.

The hand wheel is attached to the short shaft, and its drive
pinion is held in place by a brass cover of the internal gear case. As
the drive pinion of the shaft is in mesh with the three pinions mounted
on the stubs of the steering column proper, and these three pinions
are in mesh with the internal ring gear, any movement of the hand

125

466

GASOLINE AUTOMOBILES

wheel will rotate the drive pinion on its shaft. This movement will
cause the three spur pinions to rotate in an opposite direction against
the internal gear, thus reducing the movement of the steering column
as compared to that of the hand wheel. The three spur pinions
compensate for any pressure of the drag link and the tie rod.

The operation of the Ford steering-gear mechanism explains the
basic principle of the operation of the hand wheel; that is why the
wheel is turned in the same direction that the driver desires the car to

~JHvr//y Post

Fig. 331. Ford Planetary Steering Gear — An Unconventional Type

go. If the hand wheel is revolved from left to right, for example, the
movement causes the three pinions mounted on the pins of the steering
column to rotate from right to left; the pinions rotating against the
stationary internal gear turn the steering rod in the same direction
taken by the three pinions. The column swings an arm attached to
it from right to left, and, as the rod is secured to this arm, it moves
in the same direction, swinging the front road wheels so that they
move from left to right, and to a degree that will correspond with the
turning, or movement, of the hand wheel. It should be understood
that the movement from left to right refers to the front half of the
road wheels. If the driver desires to direct the vehicle to the left,
the wheel is turned to the left.

126

Digitized by

Google

GASOLINE AUTOMOBILES

467

The drag link of the Ford steering gear differs from conventional
designs in that it is at right angles to the frame and is practically
two-thirds the length of the tie rod. The end of the steering column
is provided with an arm carrying a ball, and the drag link, or steering-
gear connecting rod, as it is listed by Ford, has a ball-socket
cap which fits over the ball of the steering rod. The drag link also
has a ball socket at its other end, which fits over a ball arm on the tie
rod. The tie rod, called the spindle connecting rod because it con-
nects the spindles, is provided with yokes at either end, and these
yokes are pivotally connected to the spindles by a bolt passing
through them, and
through an eye in the
spindle. The Ford drag
link differs from others
in usual practice in that
it moves to the right and
left, while those used on
other cars move forward
and backward. No pro-
vision is made with the
Ford drag link for absorb-
ing shocks or for auto-
matically compensating
for wear as usually is the
case with the conven-
tional type of drag link.

Semi-Reversible Gear. The steering gear used on commercial
cars, particularly trucks ranging from 3- to 7-ton capacity, must not
only be capable of operation with a minimum effort, but it must
absorb a great many of the minor shocks and a per cent of the larger
shocks. The semi-irreversible type is most favored because of the
above-named reasons. The design shown in Fig. 332 is of the screw
and nut type. The nut is a solid piece, completely enveloping the
screw, and the threads of the screw are in constant and complete
engagement with the threads in the nut. The screw has a rotary
motion and the nut has a longitudinal motion. The means of trans-
mitting this longitudinal motion of the nut to the rotary motion of
the steering arm is by circular discs at the lower end of the nut.

Fig. 332. Screw and Nut Gear Used on Trucks

127

Digitized by

Google

468

GASOLINE AUTOMOBILES

These discs present constant bearing surfaces to the recesses in the
nut, and are provided with slots into which the projecting levers from
the rocker shaft fit. The screw pulls the nut up or down in the
housing, and there is no tendency for this nut to be moved sideways.

Fig. 333. Worm and Gear Steering Arrangement — Semi-Reversible

The levers projecting from the rocker shaft into the swivels which
rotate in the lower part of the nut are in direct line with the screw,
so that the push and pull of the nut is in a straight line.

Removing Steering Gear. To disassemble the majority of
steering gears it is necessary to remove the unit. With the type shown

128

Digitized by

Google

GASOLINE AUTOMOBILES 469

in Fig. 333, which is a semi-irreversible worm and gear, the removal
may be accomplished by displacing the control levers at the top of
the column and dropping the unit down through the frame. The
adjustment of this type for end play is made by loosening the locking
nut A and turning down the nut B until the play is eliminated.

STEERING-GEAR ASSEMBLY TROUBLES AND REPAIRS

Lost Motion and Backlash. Lost motion of the steering wheel
does not always indicate that the steering gear is at fault, for wear in
the steering-gear assembly usually takes place first in the clevis pins,
yokes, and connections of the drag link. The spindles, spindle bolts,
and wheel bearings are factors. Despite the fact that the front road
wheels are deflected but a few degrees the spindles, bolts, or bushings
may be worn, as these parts are subject to radial and thrust loads.
The spindle bolt, which does not move, tends to wear oval; adding to
this tendency the wear of the spindle bushings, one has considerable
lost motion to contend with. Wear of the wheel bearings contributes
to the apparent lost motion of the steering gear as do the connections
of the drag link. .Taking all of these factors into consideration, and
allowing but a small fraction of an inch for play of each worn part,
the sum total may result in considerable movement of the hand wheel
before the road wheels are deflected.

Lost Motion in Wheel. While there should be a certain amount
of movement to the hafrid wheel before it actuates the road wheels,
the lost motion, as a rule, does not exceed I or f inch when the gear
is new. This amount is essential as without some free movement the
steering of the vehicle would be tiresome. Wheels may be keyed or
pinned to the column. When play exists as the result of a worn key,
pin, or slots, the remedy is to re-cut the seats and make and fit a new
key or pin. With some types of wheels the use of a wheel puller will
be necessary to displace them. Another cause of lost motion, when
the wheel is tight and linkage free from play, is a loose key retaining the
worm or gears of the steering gear proper. A simple test of the hand
wheel is to hold the tube, or post, securely and move the hand wheel.
The amount of play in the drag link can be ascertained by grasping
it about midway and trying to move it backward or forward or in the
normal direction of travel. Hold the ball arm of the steering gear
when making this test.

129

Digitized by

Google

470

GASOLINE AUTOMOBILES

The amount of backlash present in the irreversible and semi-
irreversible types of steering gears may be determined by disconnect-
ing the drag link, grasping the ball arm, and moving it up and down
and back and forth. Worn bushings in the steering-gear case are
frequently the cause of movement of the column as a whole. Another
component that should not be overlooked in the search for the cause
of lost motion is the ball arm. Movement of this member on its
shaft can usually be eliminated by tightening the nut.

STEERING WHEELS

Different Forms of Hand Wheels. Wood Rim. A variety of
material is utilized in the construction of thejwheel, which has super-

Fig. 334. Section through Typical Steering Wheel

seded the lever or tiller. The section or sections of the wheel or rim
are circular, oval, or elliptical; the oval, or ellipse, is turned upward.
The strength of the wheel varies according to the material used and
the process of assembly. The all wood wheel has not the strength of
a built-up wheel with a metal core, but it is simpler and cheaper to
manufacture. With the exception of the molded rubber type of
rim, the majority of the wheels, particularly those fitted to high-
grade cars, are built-up. Mahogany, Circassian walnut, and black
walnut are the materials favored. The wood is cut to short sectors
of an annular ring of about 2 inches in width and so glued together
as to eliminate joints.

The method of attaching the rim to the spokes of the wheel
spider is by screws, and this method is illustrated in Fig. 334. A

130

Digitized by

Google

GASOLINE AUTOMOBILES 471

indicates the wood member, B the arms, or spokes, which have a
boss through which the screw C passes into the wood. The hub of
the spider D is attached to the steering post by two keys E.

Metal Core with Wood Covering. When the wheel design is made
up of a metal core the ring is cast on the spider or integral with it.
Coverings of wood concealing the ring are used, although with some
types, a section of the ring may be noted. This type of wheel pos-
sesses great strength and the wood veneers can be secured at more
frequent intervals than in the design previously described.

Different Wheels for Commercial Use, Truck Types. For the
light delivery wagon, taxicab, and similar cars, no difference in the
steering wheel is made, but when it comes to the heavier service, there
is a need for a heavier wheel. This does not mean a heavier rim
only, but a heavier, more rugged gear all the way through. The
weight on the front wheels of a heavy truck is very great, and
the tires, which are of solid rubber, may have frictional contact with
the pavement of several inches in width. All this combines to make
turning the vehicle from the driver's seat more difficult.

For this reason the driver must have a greater leverage, which
means a larger diameter of the wheel. Then, too, the rim should be
bigger in section in order to withstand the harder use of commercial
service, and to provide for the large hands of the operators. Greater
strain upon the rim of the wheel, on attempting to turn heavier
weights with it, means that the rim must be fastened to the spider more
securely. This means more arms, the four generally used for pleasure
cars being increased to five for trucks. While this helps a great
deal, since it provides five screws instead of four, it is not sufficient,
and most of the big trucks today are equipped with steering wheels
in which the rim is built over a central metal rim of the spider.

Pleasure-Car Types. Usual pleasure-car practice varies from
14-inch up to 16-inch wheels, while commercial car sizes begin at 16-
inch and run up to 18-inch wheels on light trucks, and as high as 20-
and 22-inch wheels on heavy trucks. Rim sizes vary considerably, a
favorite for touring cars being an oval with from J- to |-inch vertical
height and a length of about ItV to 1 A inches. These figures have no
connection with commercial work, the smallest being 1 inch and on
up to 1 1 inches in height, with the long diameters varying from 1 J up
to If inches. For speed work, racing, and the like, it is usual practice

131

472 GASOLINE AUTOMOBILES

for the operator to wind the surface of the wheel with string, this
giving a rough surface upon which the hands will not slip. This is
practiced, too, by many truck drivers, who claim that the strains of
steering the big vehicle are not felt as much when the wheel is thus
wound.

To preserve the nice appearance of the steering wheel and still

Fig. 335. Molded Rubber Steering Rim on S.G.V. Car
Courtesy of S.G. V. Company, Newark, New Jersey

give the roughened surface to which the hands will cling easily, even
in wet weather, many manufacturers are making a wheel of molded
rubber, the use of this material allowing the formation of the wheel
in any desired section, as is seen in Fig. 335. As a concession to
appearances, these wheels are usually made with a plain upper surface;
the lower or under surface, however, being made in a series of depres-

132

Digitized by

Google

GASOLINE AUTOMOBILES 473

sions and humps, between which the fingers find a good resting place.
This gives a good grip, as the under side of the wheel seldom gets wet.
Folding Steering Wheels. Although tilting steering wheels were
introduced several years ago, they did not meet with favor until the
Cadillac adopted them as standard equipment. The wheel, which is
18 inches in diameter and has an aluminum spider, is hinged to drop
downward, a design facilitating entrance and exit at either side of the
car and making it possible to attain the driver's seat without squeez-

Fig. 336. Hinge Type of Steering Wheel Used on Cadillac

ing. The Cadillac wheel is shown in Fig. 336, while that used on the
King car, illustrated in Fig. 337, is of the tilting type. To operate
the design, the wheel is turned until the wheel spider arm carrying
the release button is convenient to the thumb of the right hand.
TheT>utton is pushed to the right, and, by using both hands, the
wheel is pushed forward and upward. The Herff type, shown in
Fig. 338, is of the true hinged form; the rim is thrown up and out of
the way, that is, the rim only, as the quadrant carrying the spark and

133

Google

474

GASOLINE AUTOMOBILES

Fig. 337.

Tilting Steering Wheel on the
King Car

throttle levers remains. There are several other types marketed, but
their working principles are similar.

Throttle and Spark Levers. In the usual case, the arms of

the steering wheel have the
quadrant for the spark and throt-
tle levers fastened to them. The
levers are operated within the
space inside of the rim of wood
and above the spider of metal;
the latter is usually at a lower
level by several inches, as shown
in the figure. In Fig. 334, how-
ever, the quadrant is not carried
by the spider firms, but on a sep-
arate framework 6, or spider of
its own, up above the hub of the
wheel. Over this frame-
work the spark and throt-
tle levers H and / work,
serrations of teeth in the
quadrant preventing
the levers from moving,
except when they are
sprung off by the pressure
of the fingers operating
them. In some cases,
these teeth are done away
w T ith and friction surfaces
are substituted; springs
holding the contact sur-
faces together are so light as not to interfere with the moving of
the levers bv hand.

Fig. 338. Herff-Brooka Folding Steering Wheel

STEERING ROD, OR DRAQ LINK

Operation. By the steering rod, or drag link, is meant the
member connecting the ball arm, or lever, of the steering gear to
the lever attached to the steering knuckle. This is clearly illustrated
in Fig. 339. The steering gear is marked Z), the steering arm pro-

134

Digitized by

Google

GASOLINE AUTOMOBILES 475

jecting down from it C, while the steering rod which connects the
lower end of the arm with the lever on the knuckle is marked AB.
F is the knuckle pivoted in the axle, which carries the two-end lever
E, one arm of which has the steering rod attached to it at B, while
the other carries the cross-connecting rod joining the two knuckles
together. Since the pivot point is fixed, any movement imparted to
the knuckle must result in its swinging about the pivot point and
carrying the wheels with it.

This movement is imparted by the steering rod to the end B

of the arm K. Thp sfpprinor rnrl itsplf qimnlv

Fig. 339. Typical Steering Arrangement on Pleasure Car

a constant level, although moving in a circle, the rod must have a
universal joint at one end. This is really a necessity from two points
of view: to allow the rear end to move up and down vertically while
the front end swings around in a circle; and also to allow the front .
end to swing in a circle set in one horizontal plane, while the rear end
remains stationary or practically so in that plane. In short, the two
ends move continuously, each in its own plane, but the two
planes never coincide — the one is always vertical, while the other
always stays horizontal. This necessitates at least one universal
joint. Many makers play on the safe side, and lower the cost of

136

Digitized by

Google

476

GASOLINE AUTOMOBILES

production by making the two ends alike — a universal joint on
each one.

Types of Construction. A glance at the construction shown in
Fig. 340, end also in Fig. 341, shows a steering lever made with
a ball end, or partial ball end, upon which the steering rod is
hung. In this, the partial ball is formed in the center of a bar, the
inner end of which is threaded and screwed into the steering arm,
with a nut on the outside to prevent its backing out. The ball
itself is made separately and slid on over the rounded end of the
shaft, or axis. After this a sleeve is put on, followed by a nut which
holds the sleeve up tight against the ball. The function of the sleeve
is to give the spherical end of the rod plenty of play in a sidewise

direction. This is a cheap form of con-
struction, but could have been made in
one piece had it been desirable or neces-
sary to do so. Such a form has a metal-
to-metal contact, which is hard upon both
ball and socket, necessitating frequent and
costly replacements. These replacements
are obviated by backing the ball socket
up with a spring or springs, as is shown
in Fig. 341. This form of construction
is now quite generally used; the socket of
the ball in the inner end of the rod is set
inside of a sleeve with a spring on each
side of it. These springs not only take up the road shocks but the
wear as well, the shoulder against which they rest being adjustable.
In this figure, J is the lower end of the steering lever with the ball
end. This lever is mounted in the ball socket G. A is the body of
the steering rod, which is expanded at the end to a larger diameter,
this being designated in the figure as B. Within this expanded
portion, the sleeve E at one end acts as a shoulder for the spring F.
At the other end, the outside of the sleeve is threaded to receive
the collar C with the hexagon end K. Within this, a second spring
L holds the socket up to its position. The location of the collar C
determines the tension of the spring L, and this is locked in its
position by the screw V.. Should there be wear, which necessitates
the moving of the ball toward the open, or left, end, the whole tiling

Fig. 340.

Steering Lever with
Ball End

136

Digitized by

Google

GASOLINE AUTOMOBILES

477

is disassembled and a longer sleeve inserted in place of the one shown
at E. On the other hand, ordinary wear is compensated for by
taking up on the collar C, first loosening the lock screw V.

In Fig. 342, a rod is shown assembled at the top and disassembled
into its components at the bottom. The two ends differ, one being

Fig. 341. Adjustable Form of Ball-End Steering Rod

but a simple yoke with a plain bolt through it, marked D. The
other, however, is a ball end with an adjustment and with springs
to take up shocks.

All these parts are marked in the figure and may be located by
letter. The body of the rod is marked A, the expanded end B, which
has a groove // cut in it. Into the inner end of this groove is fitted,
first, the spring F; second, the two halves of the ball socket G; and

$bwm>Q\m

Fig. 342. Cross-Connecting Rod Assembled and in Parts

third, another spring. The sleeve E closes the outer end, and over
the exterior is screwed the adjusting nut C. The nut and sleeve are
held in place by the locking pin V, which passes through the
outer nut, the shell end of the rod, and the inner spacing sleeve, the
ends being riveted over to hold it in place. This form limits the adjust-

137

Digitized by

Google

478

GASOLINE AUTOMOBILES

ment to a full half turn of the nut, while the pin would soon need
replacement if much adjusting were done, as some of its length would
be lost each time it was riveted over because of the chipping away
to allow it to be taken out.

Cross-Connecting, or Tie, Rods. The object of the cross-
connecting, or tie, rod is to connect the right- and left-hand steering
knuckles so that the road wheels will be turned alike. The general
practice is to place the rod back of the front axle, a location avoiding
the possibility of damage if an obstruction in the road is encountered,
but in some instances the tie rod is placed in front, as in Fig. 339.

Fig. 343. Finished S.G .V. Chrome Nickel-Steel Steering Knuckle and the Same

before Machining

Fig. 344. Left Steering Knuckle of S.Q.V. Car before and after Machining

The tie rod is made adjustable to compensate for any change
that may be necessary to preserve the alignment of the wheels, and,
generally, the rod is adjustable at either end. The yoke ends of the
rods are made adjustable, screwing on or into the rod proper and
secured by lock nuts or other suitable fasteners. The adjustment is
easily made. Decreasing the length of the rod increases the gather,
or distance, between the forward section of the front wheels, while
increasing it causes the wheels to toe in. This applies to the tie rod
behind the axle.

138

Digitized by

Google

GASOLINE AUTOMOBILES

479

Function and Shape of Steering Knuckles. The steering knuckles
serve as a pivot for the road wheels, enabling them to move in a hori-
zontal plane. The design of the knuckle depends upon the axle, and
the pair used on a car are different as one has a lever for carrying the
drag link. Both have integral spindles to which the tie rod is attached.
Figs. 343 and 344 illustrate the difference between the knuckles.

Fig. 845. Packard Steering Gear Parte

Fig. 343 shows a right knuckle, forged from a blank of chrome nickel
steel, while the one at its aide is the finished part. A is the place
for the outer wheel bearing, B the position of the inner bearing, C the
hole for the pivot, or knuckle, pin, D the upturned steering arm, and
E the arm to which the tie rod is attached. Fig. 344 is an example
of a left steering knuckle of the same pair, both before and after
machining. The letters in Fig. 343 apply to this knuckle.

139

Digitized by

Google

480 GASOLINE AUTOMOBILES

Lubrication of Steering-Gear Assembly. The proper lubrication
of the steering-gear assembly adds to its life, but this work is not, as
a rule, thorough. The steering gear proper should be packed with
grease, the ball and socket joints of the drag link and steering-arm
lever with a light grease; the clevis pins also should be lubricated.
The steering-knuckle pins are provided with either grease or oil cups.
A point generally overlooked in the lubrication of the steering
gear is the steering-post spark shaft and throttle-sector anchor tube,
shown in the illustration at Fig. 345, which is of interest in that
it illustrates the assembly of the Packard car. The post carries

the control-box unit. The
spark shaft and throttle tube
frequently lack lubricant and
should be cleaned and coated
with a graphite grease before
replacing when the gear is
being reassembled. The lower
extremity of the spark and
throttle members carry levers
or small bevel sectors which
operate the linkage of the igni-
tion apparatus and carburetor.
Clamping screws are generally
used to secure these parts.

SPECIAL TYPES OF DRIVE
Front-Wheel Drive. In

Fig. 346. Front Drive and Steer on Homer the Conventional type of

Laughhn Car ^ r

pleasure motor car, the energy
of the engine is applied to the rear wheels which propel the car, the
drive being a pushing one. A pleasure car, or rather a racing machine,
with a front-wheel drive — which is a pull, and held by some to be more
economical — was brought out several years ago but npt marketed.
During the latter part of 1916, a company was formed to market an
eight-cylinder pleasure vehicle, utilizing a front-wheel drive and steer
and a friction drive with an automatic pressure control.

Difficulties of Transmission. The Homer Laughlin car, a bottom
view of which is shown in Fig. 346, makes use of an original type of

140

Digitized by CjOOQIC

GASOLINE AUTOMOBILES

481

universal joint to transmit uniform angular velocity. Its design was
brought about by the fact that the rate of transmission of angular
velocity through a universal joint is not even when the shafts are at
an angle. This is the fundamental difficulty every designer of a front
drive has to overcome or suffer the twisting of the axle.

The front wheels and the flywheel must rotate at practically a
uniform speed, at least through each revolution. The irregular rate
of transmission through the universal joint must be taken up some-

fig. 347. Homer Laughlin Pedal Mechanism

where. The normal action of a universal joint at certain angles is
to make four jerks in a revolution, as it has four fast points and four
slow points. The Laughlin joint gives uniformity of rotation with
75 per cent on each side of normal, the difference being taken up by
the flexibility of the transmission parts.

Friction-Disc Transmission. The transmission is of the friction-
disc type, but the disadvantage of this form of drive — the fact that
the control is reversed — is eliminated. The usual clutch control is
provided, but the pressure is automatic. This pressure is obtained
by an eccentric connection by means of which designers obtain irre-

141

Digitized by

Google

482 GASOLINE AUTOMOBILES

versible application of spring pressure. The transmission locks at the
correct pressure through the friction of the eccentric. The spring
controlling the friction for driving provides the proper pressure for
running, but it is not sufficient for starting or climbing long hills in
the low gear. The pedal shaft operates a dog that presses down on
the eccentric sheave extension. To de-clutch, the operator presses
the pedal down, releasing the clutch. The pedal has two points at
which it latches, providing extra pressure, and an extra spring is
brought into service for the high and low speed. This spring operates
through a toggle linkage. As the pedal rises, the applied power
increases. When the car attains momentum, the driver depresses
the pedal until it latches. The running pressure is sufficient to hold
the engine in all gears except the low and reverse.

Control. Complete control is obtained through one gearshaft,
the lever working forward for progressive, and back for reverse. Auto-
matic latching is obtained in every gear, the latch working in sockets
sunk in the jackshaft. Chain drive is employed between the trans-
mission and front axle. The brakes are located on the rear axle.
Fig. 347 shows the method of obtaining a conventional pedal control
of the transmission through the irreversible application of spring
pressure — one spring for ordinary service, the other for low gear work —
controlled by the eccentric on the jackshaft of the driving mechanism.

Four-Wheel Driving, Steering, and Braking. The four-wheel
drive — a construction in which all four wheels of the vehicle drive,
and frequently steer and brake — is confined to commercial vehicles.
A brief consideration of the actions which may have to take place at
the same time in such an axle will give a very good idea of the problem
which must be worked out. The wheels must be free to turn about
the axle as an axis, being driven from their hollow centers; the wheels
must also be free to turn about the pivot point as an axis swinging in
a horizontal direction and must be driven steadily all the time.
All the turning, swinging, and driving action must be outside of
and beyond the spring supports of the chassis, since the body cannot
turn; but the axles must at the same time support the springs.
Further, if all four wheels are to carry brakes, they must be appli-
cable at any and all times and at any and all angles of inclination of
the wheels, either in a vertical or horizontal direction, and they must
be so equalized as to apply equally to all wheels, no matter how the

142

Digitized by

Google

GASOLINE AUTOMOBILES

483

force is applied to the system, and no matter in what position the
wheels may be.

The advantage of the four-wheel drive and with it the four-
wheel steer and brake is granted by eminent engineers, as is also its

Kig. 348. Side View of a Four-Wheel Drive, Steer, and Drake Motor Truck

necessity for heavy commercial trucks, but its use has not been
extensive for the simple reason that it is a complicated arrangement
at best. In many cases, the design has been so complicated and
unmechanical as to cause failure, and the reports of these troubles have
given the four-wheel driving, steering, and braking device a sort of
visionary air, so that any one talking of it is supposed to l>e a dreamer.
Such is not necessarily the case, for many different practical four-
wheel combination driving, steering, and braking devices have been
brought out, built, tested, and proved efficient.

A number of four-wheel designs for commercial cars are being
marketed, and have proved the contention of their makers that they
are economical in operation and maintenance.

Four-Wheel Steering Arrangement. With the design shown at
Fig. 348, steering knuckles are eliminated, the wheels being con-

Hf. 349. Details of Axle of the Four-Wheel Drive Truck Shown in Fig. 348.

nected to the axle ends through the medium of vertical trunnions.
These trunnions bear on the wheel ball-bearing ring, which is ample
in diameter and turns freely because of its size and the use of ball

143

Digitized by

Google

484 GASOLINE AUTOMOBILES

bearings. Within this ring, the axle terminates in what is practically
a universal joint, driving through to the outside of the wheels. The
wheels are thus free to run about a point in the axle ends, at the same
time taking their power through the inside rotating shaft. Fig. 349
illustrates one of these axles with the parts lettered. Here H is the
point of attachment of the driving propeller shaft, G the cast-steel
one-piece case, F the differential gear within the large driven bevel
gear 0, MM the vertical trunnions upon which the wheels rotate, and
NN the universal joints which drive the wheels.

How the steering is obtained is shown in Fig. 350. At the front
of the chassis is the steering wheel P; turning it partially rotates the
longitudinal shaft Q, which extends the length of the chassis. This
shaft carries levers RR near its two ends, which are connected to

Fig. 350. Diagram Showing Steering Action of a Four- Wheel Drive Truck

the steering rods SS. These rods connect to the steering levers U U 9
which are fixed to the wheels themselves instead of to the steering
knuckles as in the ordinary case, for this car has no steering knuckles.
In addition to the steering rods attached to the longer of the two steer-
ing levers, there is a cross-connecting rod TT at each end, which con-
nects the two steering levers. Thus, when the levers R R move the
rods SS, and through these the levers U U, which in turn move
the wheels VV, the rods TT also come into play and move the
levers WW and the wheels XX. Therefore, the movement of the
steering wheel in any given direction, as to the right, turns all four
wheels, the front two to the right, and the rear two to the left so
that they form arcs of the circle in which the front ones, are turning.
The truck thus makes the desired turn to the right in one-half the

144

Digitized by

Google

GASOLINE AUTOMOBILES

485

distance or time of the ordinary
truck. Four-wheel steering then
has the advantage over two-
wheel, or ordinary, steering, of
requiring only one-half the space
and one-half the time to accom-
plish a given turn. The vehicle
described would turn completely
around in a circle of 40 feet, the
outermost circle shown in Fig.
350 being 56 feet in diameter.

Chain Four-Wheel Drive.
Fig. 351 clearly illustrates a bot-
tom view of the Hoadley four-
wheel drive, four-wheel steer, and
foijp-wheel brake truck. The
power of the engine is trans-
mitted through shafts, gears, and
universal joints to the differen-
tials; there is a third differential
in the gear box at the center of
the frame. Final drive is by
chain; both ends of the truck are
exactly alike in so far as the four-
wheel drive is concerned, and the
fifth wheels run in ball bearings.
Steering is accomplished by means
of worm gearing, the shaft being
clearly shown, and both sets of
wheels are steered simultaneously.

Jeffery Quad. An example
of the successful development of
the four-wheel drive is the Jeffery
Quad, Fig. 352, which has given
an excellent account of itself in
government work. In this type
it will be noted that the inclined
driving shafts, shown in Fig. 348,

145

Digitized by

Google

486 GASOLINE AUTOMOBILES

have been carried up to the gear box with a universal joint on either
side. This construction has resulted in a much more inclined shaft
in each case, but it has also eliminated the tail shaft D, the use of a
silent chain E with its housing, the central universal joint, and the
spherical bearing K, and, in addition, it has simplified both shafts.
In the four-wheel drive vehicle the engine was placed on the
center line of the car; on the Jeffery it is set off to one side, while the
two driving shafts to the front and rear axle, which form a continua-
tion of each other, are set off to the other side. This result is produced
by making the transmission very wide with three side-by-side shafts,
as ahown in Fig. 353. The engine drives the splined shaft 77, on which
are gears that transmit the rotation to the intermediate shaft C, which

through the final gears E and F, drives the final shaft, which is in two

Fig. 352. Plan View of the Jeffery Quad, Showing Disposition of Units
Courtesy of Thos. B. Jeffery Company, Kenosha, Wisconsin

parts, B driving one pair of wheels, G driving the other pair. Note
that the differential has been incorporated in this type of drive,
so that it is possible to have a different drive for the front wheels
from that for the rear wheels.

The rest of the construction is too simple to require a detailed
description beyond the simple statement that the gear box gives four
forward speeds and one reverse. When the two ordinary shifters
are in the neutral position shown, reverse is produced by shifting
the double reverse gear on shaft D along until its left-hand member
meshes with the second-speed gear on shaft A and its right-hand
member with the low-speed gear on shaft C.

Universal joints fit on the two tapers B and C with shafts
inclined to the two axles. On top of the stationary axle of the I-beam

146

Digitized by

Google

GASOLINE AUTOMOBILES 487

section is fixed a small box which contains the bevel gears and a*
additional differential with suitable bearings, the whole being
enclosed. These can be seen in Fig. 352, that on the rear axle being

Fig. 353. Plan View of the Transmission of the Jeffery Quad, Showing the Shafts for Both Axles

plainly shown, while the one in front is partly obscured. This
member is shown in detail in Fig. 354, which gives the longitudinal
section along the driving shaft at the left, in which the axle H is
noted, the bevel gear /, and the bearings for radial and thrust loads

Fig. 354. Sections Showing Bevel Drives at the Axles on Jeffery Quad

at J and A', respectively. The driven shaft is seen at L, with the
sleeve M around it, the sleeve being used to drive to the differential
case, since the larger, or driven, bevel C is not sufficiently large to
house the differential P.

147

Digitized by

Google

488

GASOLINE AUTOMOBILES

Fig. 355 is a diagram showing the details of the axle end and
wheel construction. In this, H is the I-beam section of the axle bed
shown in Fig. 352, and N one of the shafts, which carries at its
end the universal joint Q, with the end of the shaft extending beyond
the joint R. The latter carries the spur gear S, which meshes with

Fig. 365. Section through a Wheel and Axle End of the Jeffery Quad, Showing
Method of Driving and Steering

the internal gear T fixed to the wheel and drives the vehicle in this
manner. It will be remembered that this is not necessarily a front
wheel, but any one of the four.

The wheel turns on the spindle U, which is part of the steering
knuckle V; this knuckle turns upon the pivot W. The lever which

148

Digitized by

Google

, GASOLINE AUTOMOBILES 489

turns the wheel is attached at X, the pair (either both front or both
rear wheels) being connected by means of a cross-rod; at one end of
this rod there is a connection to a rod which runs the entire length
of the chassis. This rod is operated by means of the steering gear,
and imparts the same motion to the front wheels as to the rear,
except that the two are in opposite directions, that is, front wheels
turn to the left and rear wheels to the right, so that they will follow
around in a correct circle.

Advantages of Four-Wheel Drive. It is claimed for the four-wheel
drive that its four-wheel steering reduces the mileage traveled to the
minimum in that the car can run closely to corners and travels less in
crowded traffic, in turning around, and in approaching and leaving
loading platforms. The push of the rear wheels and pull of the front
wheels enables it to surmount obstacles instead of bumping over
them, and its greater traction permits it to travel soft roads not
easily negotiated by the rear-drive type of trucks and cars. The
four-wheel drive type will turn in a 48-foot circle, and, with its lock-
ing differential, obtains traction on slippery roads.

Electric Drive. When the final drive is electric, or when the
source of power is an electric motor, the matter of four-wheel driving
is much simplified, the wheel carrying the electric motor attached
directly to it and turning with it about the knuckle pin. Both
wheel and motor are turned by means of a worm and gear above, the
wheel being attached to the upper end of the steering-knuckle pin
prolonged. Turning this turns the wheel and motor.

This steering wheel is turned by the worm, which is on one end
of a cross-shaft. This shaft is carried in bearings above the stationary
bed of the axle and has near the center a bevel gear that meshes
with another bevel, which is, in turn, attached to the lower end of the
steering post. Turning the steering wheel turns the post and the
bevel gear j which turns the bevel pinion and with it the worm shaft.
The shaft turns the worm and the worm wheel which actuates the
road wheels. The driver thus has a triple reduction between himself
and the wheels, giving him this much advantage in steering: there is
the leverage of the wheel of large diameter, the ratio of the sizes of
the two bevels, and the ratio of reduction of the worm gearing, which,
in addition, is irreversible. The steering gear is thus eliminated and
four simple gears substituted for it.

149

Digitized by

Google

490 GASOLINE AUTOMOBILES

Couple-Gear Type. In the Couple-Gear wheel, which is an
American product, the motor is placed inside of the wheel — a type
especially designed and constructed for this purpose. With the
motor in this position, the wires enter through the hollow hub,
altering its construction very materially. As compared with the
electric motor on each wheel, previously described, this form has the
advantage of greater simplicity, fewer parts, superior appearance,
and protection against the elements, while the enclosed position of the
motor, which is the most delicate part of the machine, protects it
against road obstructions and accidents. This arrangement also

simplifies the steering
problem, since the car is
steered just the same as
any other truck, much
of the complication inci-
dent to an electric motor
on each wheel being elim-
inated.

Fig. 356 is a view of
the wheel with the tire
removed and the whole
disconnected from the
axle ends. Aside from
this, it is complete and
ready for use. Note how
the axis of the motor is

Fig. 356. End View of Couple-Gear Electrically Driven ^ &t * VeTy Sl ' ght ***&>
Wheel with Tire Removed j us t sufficient tO allow a

pair of very small driving gears at the two ends of the armature shaft
to drive on opposite sides of the wheel. The wheel is assembled with a
pair of driven gears on either side, these being separated a compara-
tively small distance, about 2\ to 3 inches. As stated, the armature
shaft has a small bevel pinion on each end, each of these meshing with
the driven gears, but on opposite sides. It is this arrangement which
gives the device its name of Couple-Gear. In this figure the brake
band has been removed, but the brake drum will be seen just inside
the wheel at A. Beyond this is noted the spindle B, which is made
hollow for the wires from the battery and turns in a bearing on the axle.

150

Digitized by VjOOQlC

GASOLINE AUTOMOBILES 491

In the second illustration, Fig. 357, an axle, either front or rear,
with the wheels removed, is presented. In this cut the left wheel is
entirely removed, but the one on the right shows the axle spindle B,
the method of fixing it in the axle support at C; the armature housing
D is normally within the wheel and not visible. One feature peculiar
to this arrangement is the steering, which is effected by means of
a vertical post with a small spur gear at its lower end E. This
meshes with a curved rack F, which is machined on the outside of
a pivoted member G, to which a pair of arms are attached. One of
these arms H has a rod /, which runs to and operates the right-hand
spindle B, while the other J has a similar rod A", which operates the
left-hand wheel. When all four wheels are to be driven in this
manner, the post is vertical, but the connection with the rack F

Fig. 357. The Couple-Gear Axle and Parts, Showing Method of Operation
Courtesy of Couple Gear Freight Wheel Company, Grand Rapids, Michigan

becomes horizontal, with a continuation to the rear axle which
operates the various arms, levers, and rods there in the same manner.
This particular system is used for heavy commercial work only,
and in this it has been particularly successful as a tractor, a front axle
and a pair of wheels being substituted for those of a heavy trucking
wagon. Then, with a sling under the body or beneath the driver's seat
for the batteries, and with proper wiring, control levers, and steering
wheel, the truck becomes electrically driven.

FRONT AXLES
TYPES
Classification. Generally speaking, front axles may be divided
into about five classes: the Elliott, the so-called reversed Elliott, the
Lemoine, the front-drive form, and the fifth-wheel form.

151

Digitized by

Google

492 GASOLINE AUTOMOBILES

These typical forms of axles are themselves subject to further
subdivisions. For example, there are many different forms of Elliott
axles, each manufacturer having what is practically his own form.
Again, the Lemoine, when used by other firms, has been built in a
practically new form, taking the second maker's name. Thus the
form of front axle made by Lemoine for Panhard is so different as to
be called the Panhard, and not the Lemoine. The same is true of
the Lisses axle made by Lemoine. In this country, it is claimed
that the axles made by Timken are sufficiently different from the
Elliott and reversed Elliott, from which the principle was taken, as to
deserve the name of Timken axles. It should be borne in mind that
in the following description of the various axle types the forms of
material, and the shape, size, and kinds of bearings used do not alter

Fig. 358. Elliott Type of Front Axle and Steering Knuckle

the principle upon which the axle is constructed, although they do
alter the appearance.

Elliott Type. In general, a front axle consists of a bed, or axle
center; a pivot pin or knuckle pin upon which the knuckles may turn;
and the knuckles themselves with the attachment for turning them.
The Elliott type, Fig. 358, the form in which the end of the axle
takes a U-shape, is set horizontal and goes over the knuckles.
The knuckles have plain vertical ends bored for the pivot pin, which
passes through and has its bearing in the upper and lower halves of
the axle jaw. In this form, the thrust comes at the top, where the
axle representing the load rests upon the top of the knuckles that
represent the point of support.

Reversed Elliott Type. In the reversed Elliott front axle, as the
name would indicate, the action is just reversed in that the axle end

162

Digitized by

Google

GASOLINE AUTOMOBILES 493

forms a straight vertical cylindrical portion bored for the pivot pin,
while the knuckles are so formed as to have jaw ends which go over
the axle ends. The thrust comes at the bottom of the knuckle,
where the axle bed rests upon the upper face of the lower jaw of the
knuckle, the axle representing the load and the knuckle the support,
just the reverse of the previous case.

This will, perhaps, be made clearer by illustrations. In Fig.
358, as already mentioned, the axle has the jaw ends, and the thrust
comes at the top. This is indicated in the figure by the letter A,
which calls attention to the thrust washers at the top. Fig. 359
shows an axle of the reversed Elliott type, this being the front axle

Fig. 359. Reversed Elliot Type of Front Axle and Steering Knuckle

for a heavy truck. In this the thrust washers A are at the bottom,
and are of hardened steel, ground top and bottom to a true surface;
the upper surface is doweled to the axle, while the lower is doweled
to the knuckle. This form has the real advantage of concentrating
all of the difficult machine work and assembling it into one piece,
the knuckle. The Elliott type, on the contrary, makes the knuckle
and axle difficult pieces to handle in the machine and afterward, this
being shown in the cost. Ease of machining the bed of the axle
is a great advantage, for the axle will average about 44 inches in
length for a standard tread of 56£ inches, and longer for wider treads,
up to a maximum of about 48 inches for the wide-tread standard in
the South.

153

494

GASOLINE AUTOMOBILES

The ordinary automobile machine shop is not fitted up for work
of this size, particularly in machine tools other than lathes, and this
job could not be done on a lathe. The result is that it becomes a task
to handle it, necessitating special and expensive rigging for that one
job. This was the case with the axle shown, a boring mill of the hori-
zontal type and a large size milling machine being used on it. Both
of these had to have special fixtures, which were useless at other times,
to hold and machine these parts. At that, this job was much easier
than an axle of corresponding size in the Elliott type would have been.
Lemoine Type. The Lemoine type of front axle differs from
those described in that the axle proper bears upon the top or bottom
of the knuckle-pin part of the knuckle, the two being made as one;
that is, an extension or a jaw of the axle does not support the knuckle

as with the Elliott type.
When the steering knuckle
of the Lemoine type is
mounted below the axle
stub, the latter is carried
higher than with the re-
versed Elliott, so as to
rest upon the top of the
knuckle. An advantage of
the construction from a
manufacturing viewpoint
is the cost of machining.
With this design, the thrust load is practically entirely at the bottom
upon the knuckle, which also must take all side loads; it is fastened
in a sidewise direction at but one point — the bearing in the axle. The
side shocks are taken on the end of a beam fixed only at the other
end, whereas with the other types, the load is distributed between
two supports, or divided equally over two sides, the point of support
being midway between them. With the Lemoine type discussed,
the bottom bearing must compensate for radial and thrust loads —
a difficult condition to meet.

While the design is easy to machine, assemble, and handle, its dis-
advantage is that the knuckle has a double duty, having, as it does, both
radial and thrust loads to care for because of its one-piece construc-
tion. This type of axle is, however, very popular with foreign designers.

Fig. 360. Inverted Lemoine Type of Axle
as Used on Overland Cars

154

Digitized by

Google

GASOLINE AUTOMOBILES 495

Inverted Lemoine. A novel type of axle has been created in the
1916 Overland car, Model 75, called an inverted Lemoine. In
this type, as Fig. 360 shows, the wheel spindle, or stub axle, is at
the top of the steering knuckle instead of at the bottom as in the
case of the regular Lemoine type. The knuckle has a single, fairly
long support in the end of the I-beam front axle, the forging being
much simpler on this account. In fact, this makes the axle nearly
straight, which doubtless accounts in large part for this unusual
design. One real advantage of this design is that it allows the car
weight to be low in relation to wheel bearings, thus assisting in steering.

Courtesy of Nordyke and Mormon Company, Indianapolis, Indiana

Marmon Self-Lubricating Axle. The new Marmon front axle,
Fig. 361, is of the inverted Lemoine type similar to the Overland,
shown in Fig. 360, but at first glance it looks quite different. For
one thing, the bearing in the axle end is different, and in this
lies an exclusive and valuable feature. The stub-axle pivot pin,
made integral with the stub axle, is placed in a split bushing, which
is a tight fit at the bottom — where the thrust collars are formed in it —
and at the top, but not in the middle. When this bushing is in place,
the knuckle and bushing are forced into the axle end from above,
and a kind of hub cap screwed on at the bottom. This holds it
permanently in place.

155

496 GASOLINE AUTOMOBILES

Near the middle of the split bushing there is a narrow slot to
which a central bolt hole is connected. On being assembled, the
inside is filled with lubricant, which cannot escape; but, as it wears
away, the central bolt can be removed, more lubricant can be poured
in until it is full, and the bolt replaced to prevent leakage. In this
way the axle is self-lubricating, and, as the oil is used up very slowly, it
needs practically no attention.

Fig. 362. Front Elevation of Car, Showing Camber of the Front Wheels

Like the Overland, this arrangement of the axle end brings the
axle down low, relative to the weight, and consequently steering is
made easier. The lowering of the axle also brings the points of
spring support down and thus lowers the whole car.

Camber Somewhat Complicates Axle Ends. All front wheels
are dished, that is, the spokes do not lie in a flat plane but in the
form of a cone, with the point of the cone at the outer end of the
hub and the base of the cone at the rim of the wheel. Now all roads

156

GASOLINE AUTOMOBILES 497

and most all pavements are made with a camber. The center of the
road is made higher than the sides so that the road will drain. It
is necessary, in order to have the lower spokes plumb or perpendicular
to the road surface, to throw the center line of the wheel out of the
vertical plane 2 or 3 degrees. This offset is also called camber, and
it complicates the construction of the axle ends to such an extent
that they must be machined with this slight angle either in the
knuckle or in the axle, or distributed over the two places.

Fig. 362 shows the effect of this camber upon the front appear-
ance of the car, the slight angle of the front wheels giving the car a
bow-legged appearance.

Gather Further Complicates Axles. What the carriage men
term ' 'gather* ' further complicates the axle ends. This is the practice
of setting the axle so that the front wheels are closer together at
the front than at the rear, that is, they toe in. The idea of this is
to make steering easier and, more particularly, to make the car
self-steering on plain, level, straight-ahead roads. It is scarcely
noticeable from in front, but is from above. Although many cars
still have it, it is not used as much now as formerly.

MATERIALS

The materials utilized for front axles include castings of steel,
manganese bronze, iron, and other metals, in the form of forgings,
drop forgings, drawn or rolled shapes, and pressed shapes. Wood
has been but little used and only in the past.

Cast Axles. Castings for front axles have been looked upon
with grave doubt and fear by designers and owners, because of
the fact that road shocks are more severe for front than for rear
axles, and because of the fear that a casting may have a blowhole
or some other defect. In addition to the natural distrust of castings
for this work, it was feared that such material would crystallize more
quickly than would a better and more homogeneous material like
steel. There is, of course, a certain amount of crystallization in all
materials, but far less in a close-grained fine-fibered structure like
forged or rolled steel than in any form of casting. Aside from this,
castings present many other advantages which are well worth while.
Thus, the spring pads may be cast integral with the axle with prac-
tically no extra charge, while the same forged integral with a drop-

157

498 GASOLINE AUTOMOBILES

forged axle may easily add several hundred dollars to the cost of the
dies. Again, with casting patterns, the fillets may be changed easily
to give a greater section here or to reduce a section there, while a
similar action with any forged axle means a new set of dies, costing
perhaps $600. There are many other machining helps which may
be provided in cast axles without any extra cost.

Notwithstanding these many advantages, the casting for the
front axle has been and is distrusted, and the makers who have used
it have flown in the face of popular prejudice, for the public has
mistrusted it even more than the makers. For this reason, the cast-
ing has been little used, and the writer fails to recall a single car
with a cast axle now on the market.

Forgings. Forgings, as distinguished from drop forgings, are
much used for good front axles, but are expensive. The writer knows
of one excellent truck builder, striving to build the best truck in the
world, who is using a hand-forged front axle, the end of which is
shown in Fig. 359. It is forged down from a 6-inch bar of selected
steel and the ends worked out so as to leave the bed proper a 2$- by
2|-inch section, which later has been increased to 3 inches square.
This made a very costly piece of work, but the stand-up qualities
shown in actual work more than made up for it as long as people could
be found to pay the price demanded for a truck made along these lines.

Many smaller makers follow out the same scheme, the lighter
work allowing the axles to be forged up much more quickly, more
easily, and more cheaply. The smaller the amount of material to
be heated, the less difficult will be the work, and the more quickly
will progress be made. The general trend of axle practice today,
however, is to turn over the axle job to specialists in that line, most
of whom employ drop forgings, drawn- or rolled-steel tubing with
drop-forged ends, or similar rapid-production forms of construction.

Drop Forgings. Drop forgings are now more used than any other
form, although the first cost is great, for the dies must be very care-
fully worked out in a very high grade of steel; the result is a large
expense of possibly $600 to $750 before a single axle is turned out.

As a matter of fact, with drop forgings, after the die is once
made, the axles may be turned out rapidly, accurately, and with
little labor and cost. Given the dies, therefore, there is no doubt
that this method produces an axle at a very low first cost. Moreover,

158

Digitized by

Google

GASOLINE AUTOMOBILES

499

the method itself produces better quality, for any process which
works steel or wrought iron over and over again improves its quality,
provided the steel is not burned in the process of heating. Not only
are the majority of axles made of drop forgings, but of those not so
made some part is almost sure to be a drop forging, as, for example,
those made of steel tubing which have their ends or other parts
made by the drop-forging process. In Fig. 363 is shown a drop-
forged axle used on a truck.

Tubular Axles. The I-beam section of front axle is universally
used, and while the tubular type formerly enjoyed some popularity,
its use today is confined to a very few vehicles. When employed,
its ends are drop forged or drawn, or rolled steel may be used
with the ends welded or otherwise secured. The disadvantage of
the tubular type is the fastening of the ends which is more or less
offset by the lowered cost of material.

Fig. 363. Typical Drop-Forged Axle Used on Truck

Drop-Forged Ends. Nearly all the ends for axles made in this
way are drop forgings, very few castings being used, while the spring
pads, or spring seats, as they are sometimes called, are split into
upper and lower halves and bolted on.

The loading conditions of all front axles are such that the load
rests on the axle at two points inside of the supporting points —
the wheels. Thus, the continual tendency of the load acting down-
ward and of road shocks acting upward is to bend the center of
the axle still further downward. Since a tube which has been bent
once has been weakened, it follows that this tendency to weaken it
presents a further source of trouble.

Pressed-Steel Axles. The pressed-steel type of axle, which
made its initial appearance in 1909, and is not generally employed,
consisted of a pair of pressed-steel channel shapes — one being

159

Digitized by

Google

500

GASOLINE AUTOMOBILES

slightly larger than the other — set together with the flanges
inward so as to present a box-like shape. When thus arranged, the
two sections were riveted together by a series of rivets running ver-
tically along the center part of the channels. The ends consist of
drop forgings, machined to size* or space between the channels when
assembled, and then set into place between the ends and riveted.
The pressed-steel construction obtained a secure attachment to the
bed. This axle was of the Elliott reversed type.

Change of Axle Type Simplifies. Often the change from one
type of axle to the other is not made because the latter is better but
because of some incidental saving in the manufacture. Thus, in

Fig. 364. Differences in Construction of Reversed Elliott and Elliott Types of Axle Knuckle

Fig. 364, we see the reversed Elliott type at the left at A and the
Elliott type at the right at B. From a manufacturing point of view,
the former is much cheaper to construct, for the axle and knuckle
costs would just balance one another, but the forging and machining
of the one-piece steering arm shown in B would be more than double
that shown in A. Moreover, the number of dies and their cost
would be about three times as much, while the customer would have
to be charged two or three times as much for repair parts. That is,
in a modern low-priced car, produced in tremendous quantities, the
advantages and costs connected with the two-piece steering arm of
A would influence the choice of that design, regardless of other
advantages or disadvantages.

160

Digitized by

Google

GASOLINE AUTOMOBILES 501

AXLE BEARINQS

Classification. Thus far nothing specific has been said about
axle bearings. These are, according to construction, of three kinds:
plain, roller, and ball. From the standpoint of the duty which
they are to perform, bearings may be divided into radial-load and
thrust bearings, all three forms mentioned above being used for
both purposes, but arranged differently on account of the difference
in the work. Each one of the three classes may be further subdivided.
Thus, plain bearings may be of bearing metal or of hardened steel,
or they may even be so constructed as to be self-lubricating. Again,
plain bearings may mean no bearings at all as in the old carriage
days when the axle passed through a hole in the hubs, and whatever
wear occurred was distributed over the inside of the hubs, resulting

Fig. 365. Front Axle End, Showing Roller Bearings for Wheel
and Steering Knuckle

after a time in the necessity for either a new set of hubs or a new axle,
or for the resetting of the axle, so that the hubs set further up on a
taper. Roller bearings may be of several classes, some makers using
both straight and tapered rollers. In addition to these there are
combinations of the straight and tapered types, and bearings with
two sets of tapered rollers acting back to back, the action being that
of straight rollers, with the end-adjustment feature of the tapered
type. There are also many types of ball bearings, as, for example,
plain ball bearings — those working in flat races, those working in
curved races, those working in V-grooved races, and single balls
working alone. There are also combinations of balls in double rows.

Digitized by VjOOQIC

502 GASOLINE AUTOMOBILES

Roller Bearings. Fig. 359 shows the use of tapered roller bear-
ings for the hubs and of hardened-steel thrust washers for the thrust
load, the figure showing, in addition, a plain brass bushing in the
axle for the knuckle pin to turn in. In Fig. 365 is shown a more
elaborate use of roller bearings of very excellent design. In addition
to the axle bearing, it will be noted that the top bearing of the steer-
ing knuckle is of the roller type.

Ball Bearings. Although there is a growing tendency to utilize a
short adjustable type of roller bearing, many designers favor the ball
bearing. The two most common forms are the cup and cone type,
which cares for radial and thrust loads, and the annular form which

Fig. 366. Front Axle and Steering Knuckle of Superior Construction

is suited for supporting annular loads. The annular form is not
adjustable, and when it wears it must be replaced with a new bearing.
The cup and cone type is adopted by makers of low-priced and
medium-priced cars, has an angular contact, and is adjustable.

In some instances, particularly with high-grade cars, ball bearings
are used for the knuckle bearings as well as for the hub. Fig. 366 is
an example of an axle end, which for real bearing worth, has probably
never been surpassed; this is the axle end and steering knuckle of a
very high-priced car, not now made, but one on which no expense
was spared to make it perfect. The illustration shows the wheel
hubs running on two very large diameter ball bearings, while the
knuckle also turns on two very large ball bearings arranged for

162

Digitized by CjOOQIC

GASOLINE AUTOMOBILES

503

radial loads. At the top is another ball bearing arranged for
thrust; this bearing taking up all thrust loads from the weight above
or from road inequalities. Fig. 367 illustrates the cup and cone type,
This design utilizes ball bearings for the hubs and plain steel thrust
washers on the knuckle.

FRONT AXLE TROUBLES AND REPAIRS

Alignment of Front Wheels Troublesome. The lack of align-
ment of front wheels gives as much trouble as anything else in the

Fig. 367. Front Axle Details of Waverley Electric Car
Courtesy of the Waverley Company, Indianapolis, Indiana

front unit. This lack not only makes steering difficult, inaccurate
and uncertain, but it also influences tire wear to a tremendous extent.
As Fig. 368 indicates, even if the rear axle should be true with the
frame, at right angles to the driving shaft, and correctly placed
crosswise — correct in every particular with the shafts both straight
so that the wheels must run true — the fronts may be out with
respect to the frame, out of track with the rears, or out with
respect to each other.

In order to know about the front wheels, they should be meas-
ured; while this sounds simple, it is anything but that. In the first

163

Digitized by

Google

504

GASOLINE AUTOMOBILES

place there is little to measure from or with. A good starting place
is the tires, and a simple measuring instrument is the one shown in
Fig. 369. This instrument consists of a rod about { inch in diameter
and about 3 feet long, fitted into a piece of pipe about 2 feet long,
with a square outer end on each, and a set screw to hold the meas-
urements as obtained. By placing this rod between the opposite
sides of the front tires, it can be ascertained whether these are par-
» f

Fig. 368. Diagram Showing Front Axle and Wheels Out of True

allel, and whether they converge or diverge toward the front. But
knowing this, the driver or repair man is little better off than before,
because this may or may not be the practice of the makers of the car,
and it may or may not cause the trouble.

In short, a more accurate and more thorough measuring instru-
ment is needed, Fig. 370. Such an instrument can be bought, but a
similar outfit can be made from f-inch bar stock, using thumb nuts

j'Rodj

Qst-^Sel Screw

3&~r.---.-.-_-.-

Pipe-?

Fig. 309. Simple Measuring Rod for Truing-Up Wheels

where the two uprights join the base part, and also at the two points,
or scribers, on these uprights. Having the floor to work from, the
heights can be measured, and thus the distance between tires may be
taken on equal levels. Thus, a bent steering knuckle can be detected
with this apparatus. Similarly, the center line and frame lines of
the car can be projected to the floor, and by means of the instrument,
it can be determined whether the axle is at a perfect right angle

164

Digitized by

Google

GASOLINE AUTOMOBILES 505

with the frame lines, and whether the wheels are perfectly parallel.
Given the frame line, too, it can be determined whether the wheels
track with one another.

Straightening an Axle. When an axle is bent, as in a collision,
a template is useful in straightening it. This can be cut from a
thin sheet of metal, light board, or heavy cardboard. It is an approx-

Fig. 370. Accurate Measuring Rod for Truing-Up Wheels. Better Design than Fig. 369

imation at best and should be used with great care. Fig. 371 shows
such a template applied to an axle which needs straightening.

When the axle is bent back to its original position, a pair of
straightedges laid on top of the spring pads will be of great assistance
in getting the springs parallel, as the worker can look across the
straightedges with considerable accuracy. This is indicated in the

Fig. 371. Template for Showing if Axle Is Bent

first part of Fig. 372, which shows the general scheme. It shows also
how the axle ends are aligned, using a large square on top of a
parallel bar, but of course this cannot be done until the last thing,
at least not until the spring pads are made parallel.

Front axles of light cars may be straightened without removal,
provided the bend is not in the nature of a twist and not too short.
Take two hardwood planks 7 feet long, 10 inches wide, and 2 inches

165

506 GASOLINE AUTOMOBILES

thick. Next, cut four J-inch blocks 10 inches long and 3 inches wide.
Lay the blocks flat between the planks, space them about 2 feet apart,
and bolt the whole securely. This obtains a girder 7 feet long, 10
inches wide, and 4 J inches thick. Next, take two pieces of 4 X4 timber
3 feet long and cut a tenon on one end of each. Make three f-inch
eye bolts, 12 inches long, with nuts and plate washers for each. Place
one of the eye bolts between each pair of blocks and screw up the nuts
and washers sufficiently so as to rivet them. This permits of moving
the eye bolts to any position between the blocks. Two small steamboat
ratchets and several short but strong chains complete the equipment.

Fig. 372. Diagram Illustrating Method of Truing-Up an Axle

With an axle bent back in the center, lay the girder on blocks in
front of the car so it will be level with the axle, place the tenons of
the 4X4 timbers in the space between the planks of the girder, one on
either side of the bend, and connect the axle to the girder by means of a
chain, the ratchet, and the eye bolt. When the ratchet is tightened up,
it draws the ends of the 4 X4's against the axle on either side of the bend.
Tightening the ratchet still further removes the bend. This work
may be accomplished in 20 minutes or less or in about one-tenth the
time it will require to displace the axle, heat it, and straighten on an
anvil, etc. The apparatus can be used for straightening many differ-
ent bends; all that is necessary is a different arrangement of its parts.

166

Digitized by

Google

GASOLINE AUTOMOBILES

507

For example, a downward bend can be straightened by placing the car
above the girder, connecting the axle to the girder, and using a short
screw jack to remove the bend. This device can be used with success
in shops dealing with light- or medium-weight cars.

Spindle Troubles and Repairs. Wear of the spindle, or knuckle
bolt, and its bushings, as well as play in the steering-gear linkage, brings
about wobbling of the front wheels when the car is in motion. Some
experienced persons mistake wear of the knuckle and the bushings for
play in the wheel bearings, and attempt to remedy the trouble by
adjusting the bearings. It is a simple matter to determine the com-
ponent at fault. To test for bearing play, drive a block of wood
between the knuckle and the axle, then grasp the wheel at the top and

Fig. 373. Use of Wedge to Cure a Wobbling Wheel

bottom, or at points diametrically opposite, and test for looseness.
If none exists, the play is in the knuckle pin and its bushings. The
remedy is to fit new bushings and new knuckle pins.

Wobbling Wheels. Wobbling of the front road wheels is gener-
ally due to play in the joints of the steering mechanism, and it is not
only troublesome, but also sets up undesirable stresses on the steering-
gear linkage. This flapping of the wheels may be present with the
steering gear and linkage in perfect operating condition, and similarly
when the springs, hangers, etc., are in good condition and the proper
toe in, or gather, of the wheels exist.

When the wheels wobble it may be assumed that the front springs
have so settled that the steering pivots are not quite vertical fore and

167

Digitized by

Google

508 GASOLINE AUTOMOBILES

aft, particularly with reference to that type of pivots which do not
incline outwards and where the wheels are canted or dished to bring
their points of ground contact in line with the pivots. A cure for this
trouble is to place wedges between the front springs and spring seats
so as to alter the angle of the steering pivots, as shown in Fig. 373.
Metal wedges are used, about f inch thick at the large end, and
tapered to a knife-like edge. The wedge is placed at the forward end of
the axle, and a little experimentation will give the results desired.
In wedging, as few wedges should be used as is necessary to obtain the
desired result.

CHASSIS GROUP

In arranging a logical presentation of the numerous components
of the motor vehicle, the chassis is separated from the body. It
includes the power plant and mechanism utilized in transmitting the
energy of the engine to the road wheels, also the frame and suspen-
sion, the axles, etc. However, only frames, springs, and shock
absorbers will be discussed in this section, as the other parts of the
chassis have been treated.

Characteristics of Parts. Frames. The chassis frame practi-
cally is the foundation of a motor vehicle, since all of the power
transmitting and other units are attached to it. Motor- vehicle
construction depends, to a certain extent, upon the general design
of the chassis, the construction of the power plant and transmit-
ting units, their mounting, the method of final drive, the wheelbase,
etc The size of the material used depends upon the weight of the
units carried and the capacity of the vehicle, and varies from thin
and small sizes on very light pleasure cars to heavy structural I-beam
frames on commercial vehicles.

The use of pressed steel is becoming more popular, as is also the
tendency to narrow the frame at the front to obtain a shorter turning
radius. The majority of designers favor what is termed a kick-up at
the rear, which affords better spring action and permits of a low sus-
pension of the body. The use of tubing and wood has practically
been abandoned. There is a slight return to favor of the underslung
suspension, a form that was popular several years ago but which did
not then obtain the results claimed for it, as the springing gave some
trouble.

168

Digitized by VjOOQIC

GASOLINE AUTOMOBILES 509

Springs. The primary function of the spring is to absorb the
road shocks that would otherwise be communicated to the mechanism
and passengers. Considerable progress has been made in the past
year toward improving springs, and not only are they better pro-
portioned, but improved material and methods of mounting have, to a
great extent, eliminated breakage. The leaf type, developed by the
horse-drawn carriage industry, is the form universally employed on
motor vehicles, both pleasure and commercial. I

A review of the 1916 springs for cars showed that the three-
quarter and seven-eighths elliptic spring was favored by 46.5 per cent
of the makers, while some form of cantilever spring was second with
28.7 per cent for rear suspension. This year the advocates of the
cantilever have gained many new recruits. In the matter of front
springs, the semi-elliptic may be said to practically monopolize the
field. The coil spring is a thing of the past.

Shock Absorbers. The fitting of shock absorbers as standard
equipment is not as noticeable as it was in 1916 and the year previous.
The use of high-speed engines with light reciprocating parts, and the
employment of high-grade light material in other components of the
chassis, together with better springs, serves to absorb shocks created
by traversing rough roads. A few makers supply shock absorbers,
but, as a rule, the car manufacturer leaves the selection to the pur-
chaser. Many different types of shock absorbers are marketed, and
use is made of varying principles.

FRAMES

General Characteristics. When the automobile was first intro-
duced, comparatively little attention was paid to the frame, as the
other components of the chassis, such as the power plant, gearset,
axles, etc., were held to be of greater importance, consequently the
frame did not receive the consideration it should. After experiencing
considerable difficulty, however, due to accidents and other failures
which were traced directly to poor frame design, the automobile
engineer found that it was possible to build a frame of great strength
with less weight than the troublesome types. This statement applies
to the frame of the commercial car as well.

The improvement in frame design is the result of the tendency to
provide perfect alignment of the power plant, clutch, and gearset,

169

Digitized by VjOOQLC

510 GASOLINE AUTOMOBILES

making use of what is known as the unit power plant on some models,
while on others, particularly of the heavier type, flexible mounting
of the units has been resorted to. The tendency is toward the use of a
flexible mounting of all individual units, at least to some degree, in
order to relieve them of the stresses brought about by frame weaving
when the road wheels mount an obstacle on the road surface.

Classes of Frames. The most prominent types of frames, divided
according to their use, are the pressed-steel frame, the structural
frame, and the structural I-beam frame; the latter is confined to com-
mercial cars. These classes may be subdivided according to the
general construction and material, as well as to the distribution of
the chassis units.

The material employed is either pressed or rolled steel. The
wood frame or combinations of wood and metal frames are practically
a thing of the past, and are to be found, with one or two exceptions, on
old cars. The steel frame may be constructed in the following shapes :
channel, L-beam, angle, T, Z, tubing, flat plates, and combinations
of any two or more of these. Other forms are possible. For example,
the channel may be turned with the open side in or out, the two con-
structions being widely different; or the angle may have the corner
down and out, down and in, up and out, or up and in. Similarly, the
T-shape may be a solid T turned up or down, or it may be a hollow
T-section with space between what might be called the two sides of
the leg; this shape may be turned either up or down, while the
Z-shape may be turned horizontally or vertically. Many frames are
constructed with the open end of the channel section turned in, and
use is made of a steel underpan of flat section attached to the under
side of the main frame. In several instances there is a tendency to
make the frame and underpan as one piece, in which case the frame
section assumes the shape of a channel with ao exceedingly long lower
flange.

Another type of frame is that having a continuous section
throughout. Others have a varying section. Thus, the ordinary
steel frame of modified channel section may have a depth of perhaps
5 inches at the center, a width of upper flange of 1J inches, and a width
of lower flange of 2 inches. A frame similar to this would taper down
to the ends to perhaps 20 inches in vertical height, and to 1 inch in
width of both top and bottom flanges. Then, again, frames which are

170

Digitized by

Google

GASOLINE AUTOMOBILES 511

bent upward or downward at the ends or in the middle really differ
from those frames which preserve one level from end to end. The
practice of bending the chassis frame is very prevalent of late,
the upturning of the ends bringing about a lower center of gravity,
making for stability and ease of entrance and exit to the body.

Tendency in Design. There is a marked tendency toward mak-
ing the chassis frame wider at the rear and narrower at the front.
In one or two cases the designer appears to have gone to the extreme
in this respect. The advantage of the narrow front construction is
that it enables the car to be turned in a shorter radius. The use of a
wide rear frame provides more space to support a wider body. A
more recent development is to make the longitudinal bars of the frame
parallel over the front spring and near the rear spring, and to have
them tapered from behind the front to the rear springs. A certain
amount of material is said to be gained by this construction, as no
heavy reinforcement or sudden offset is necessary to the frame. By

Fig. 374. Typical Automobile Frame of Pressed Steel

widening the frame at the rear it makes possible the placing of
the springs directly underneath the frame. Some car makers have the
sides of the frame straight over the entire length, but tapered from
the front to the rear.

Fig. 374 illustrates what is termed a single drop or a kick-up.
This is a type of pressed-steel construction, of channel section, and
the deepest and strongest section is at the center where the greatest
stresses occur. Some frames are built with a double drop, having
a downward bend just forward of the entrance to the rear part of the
car body, followed by an upward turn just back of the same entrance.
The upward turn at the back is carried higher than the main part of
the frame for the purpose of obtaining a low center of gravity. Then
there is what is termed the bottle-neck construction, a bend inward
which resembles that in the neck of a bottle. This obtains a short
turning radius. Originally, frames were narrowed in front, the differ-
ence in the width between the front and rear being at first an inch

Digitized by VjOOQIC

512

GASOLINE AUTOMOBILES

or so on each side, gradually increasing until it became 5 and 6 inches.
This type did not prove efficient, and the trend favored the taper
previously explained.

A riot uncommon form of frame is shown in Fig. 375, which com-
pensates for an abnormal rise of the rear axle without the possibility
of its striking the frame. Some frames have a bend at the ends to take
the spring fastenings.

Pressed-Steel Frames. The pressed-steel type of frame is very
popular with designers and is largely used on commercial cars up to
and including 1-ton capacity. This is popular because it is the lightest
in weight for equal strength of the structural iron or rolled channel
and I-beam section. The cost of pressed steel is somewhat higher,

ZU2-

»-> Tiff

Fig. 375. Frame of Sterna-Knight Car in Plan

because it is heat-treated material used to obtain maximum strength.
The cost varies with the section, material, and the nature and extent
of bending. The finished frames are easy to handle, and the assem-
bling cost is small. The channel shape is easy to brace and repair.
These and other advantages have brought about its use.

The cheapest construction is the straight side rail, and, when
conditions permit, it is usually tapered at front and the rear, and the
forward end is sometimes shaped to receive the spring hangers.
When the side members are inswept to permit a short turning radius,
it is necessary to make the flanges of the side rail of considerable width
at this point, tapering gradually to the rear, to provide the proper
strength at the point of offset.

172

Digitized by

Google

GASOLINE AUTOMOBILES 513

Sub-Frames. The modern tendency is to eliminate the sub-
frame — a step due to the flexible mounting of the power plant and
unit construction — because it simplifies the frame. It has also been
made easier by the tapered frame, which is narrowest at the front
where the units are attached. The most common method of support-
ing the engine is the three-point. Sub-frames are used, however, as
they serve the purpose both of supporting some unit and of strength-
ening the frame.

Sub-frames may be of two kinds, viz, those in which the sub-
frame is made different for each unit to be supported, and others
in which one sub-frame supports all units regardless of size, shape,
or character of work. The type of sub-frame made to support each
unit usually works out to two pairs of cross-members, one for the front
of the unit and one for the rear; while the type which supports all
units regardless of size works out to longitudinal members, supported,
in turn, by two cross-members, front and rear. The added weight for
the first-mentioned type is less than for the other, since it comprises
only four cross-members; while the last-named type consists of two
cross-members equal to two of the others and of two very long members
parallel to the main-frame members, each much longer and thus
much heavier than the corresponding cross-members. In the two
frames already shown, Fig. 374 shows the unit type of sub-frame with
only cross-members, while Fig. 375 shows the more modern type in
which the power plant is of the unit type and rests directly upon the
main frame, being the three-point suspension type in which the
forward point is on a frame or special cross-member, while the rear
two points are the crankcase supporting arms resting directly on the
main frame.

Rigid Frame. A pressed-steel or rolled-stock rigid frame has its
advantages, particularly with reference to the commercial vehicle.
It permits the body to be rigidly secured to it, and as it does not give
with the inequalities of the road, the body is not racked. An advan-
tage of the rolled stock is its cheapness, except, of course, for the
lighter models of the assembled type for which frames can be secured
at low figures. Another advantage of the rolled stock is the ease
with which the wheel base may be altered.

Effect on Springs. The effect of frame construction upon the
design and duty of springs should be considered. This feature

Digitized by VjOOQIC

S£ »«S

ili

■sw*r***m«s*

.'^.-.-u-.-A.--.

ito3ZLD

=* *

■8

6 -3
.2 s*

174

Digitized by

Google

GASOLINE AUTOMOBILES 515

is not generally understood, but it has an important bearing upon the
life of the car. A rigid frame relies upon the springs to allow for all
axle displacement. If a front and a rear wheel on opposite sides are
raised several inches at the same time, the frame is subjected to a
torsional stress. If the frame is rigid, springs of considerable camber
must be employed in order to absorb the shock without being bent past
the limit of safety, and they must be sufficiently flexible to absorb all
the shock without any tendency to lift the other wheels from the
ground. To accomplish this shock absorption, a different type of
spring is used on a rigid chassis from that employed on a flexible
frame. The use of underslung spring suspension has come into favor
for this reason, as it permits the frame to be carried fairly low, without
sacrificing spring camber or necessitating a dropped rear axle.

The flexible frame, when diagonally opposed wheels are raised,
does not impose all the stresses on the springs but it absorbs
a part of them. For this reason, springs on a flexible chassis
are flat or nearly so, with a limited amount of play. Flexible con-
struction also permits the frame to be carried equally as low as with
the underslung spring, and yet the spring is perched above the axle,
where it is more nearly in line with the center of gravity, thus reduc-
ing side sway.

TYPES OF FRAMES

Pressed Steel. Pressed steel is purchased in sheet form, cut to
the proper shape in the flat, and then pressed into channel form under
great pressure. It is made of steel rolled into sheets and is somewhat
closer grained than ordinary steel. There is no breaking of the flake
in the rolling process. The pressed-steel frame, as previously pointed
out, permits of greater simplicity in assembling, since the parts can be
easily bolted or riveted. Fig. 376 is of the type of pressed-steel frame
having a tapering section, a kick-up at the rear end, five cross-members
— one of them a tube — and is narrowed in at the front to give the
largest steering lock. Otherwise it presents only standard practice.

Wood. Wood is universal and easy to obtain. While no longer
classed as cheap, it is not expensive; moreover, wood is kept in stock
nearly everywhere. Users of wood for side-frame members claim
that the wood frame is not only lighter but stronger. In addition,
the wood frame would undoubtedly possess more natural spring and

175

)16

GASOLINE AUTOMOBILES

TABLE IV
Comparative Strength of Steel Channels and Laminated Wood Frames

Material

Sise

(in.)

Weight per

Linear Inch

(lb.)

Resisting
Moment

Resulting

Moment per Unit

Weight

Pressed Steel
Ash

AX4JX1J
11X6

.408
.266

114,830
142,275

280,955

534,870

resiliency, so that it would make a lighter and easier riding frame.

A section of a wood frame is shown in Fig. 377.

This shows a frame made of laminated wood. There are three

very thin sections of selected ash, marked A, which are glued together,

then screw-ed and bolted to pre-
vent the glue from opening up.
To further this purpose, a strip li
is fastened on the top and bottom
in the same manner. These strips
are laid with the grain running
horizontally, while the main
pieces are laid with the grain
running vertically. This con-
struction makes a very strong
and light-weight frame; the com-
parative figures for a steel sec-
tion and the section shown, as
given from the tests of the engi-
neers of the Franklin Company,
is shown in Table IV. These
tests, which are authentic, seem
to bear out the contention that
the wood frame is both lighter
and stronger than the steel frame.
Novelty of Fergus F ; rame. A
new American car, the Fergus,
show T s more novelty in frame con-
struction, as w ell as in every other

conceivable way, than any other. Instead of blindly following

accepted practice in the matter of frame design and construction, the

makers have struck out boldly along new lines.

Fig. 377.

Section through Wood Side-Frame
of Franklin Car

176

Digitized by

Google

GASOLINE AUTOMOBILES

The Fergus car was developed as
a result of fifteen years' experience in
fine repair work, and is an attempt to
eliminate the usual "owner troubles".
While not intended as a "foolproof*
car, the Fergus comes nearer being one
than any other developed up to this
time. In addition to actually "fool-
proofing" the car, the aim of the
makers was to eliminate much of the
work incident to caring for the modern
car by replacing the usual "owner-
attention" with an automatic system.

In the frame, a combination of
steel girder and lattice work has been
produced which has the appearance
of being absurdly light. However, as
the diagram of stresses in its members,
Fig. 378, indicates, everything has been
figured out with the utmost care, and
the design has been supplemented by
unusual workmanship.

The complete frame, Figs. 379 and
380, shows that a large part of the
saving is produced by the method of
suspending the units. Were these
hung on the side members, as in the
ordinary case, the frame certainly
would not do, but as it is, they are
hung on immensely strong brackets,
steadied by the side members, but
rigidly supported by large tubular
cross-members. The brackets and
cross-members do the work ordinarily
assigned to the side members of the
frame, the side members simply joining
and holding together the various brack-
ets and cross-members.

177

Digitized by

Google

518 GASOLINE AUTOMOBILES

An examination of the design reveals the astonishing extent to
which the brackets have been combined, the rear engine member,
for instance, also acts as the rear support for the front spring, for

•c

S
2

the step support, and for the dash support. At the sides and rear
there is a similar combination of functions.

Recent Types of Frames. An innovation in frame design is the
Marmon, shown in Fig. 381 , the side rails and running boards of which
are made in a single unit. The great width of the running board,

GASOLINE AUTOMOBILES 519

S
V

.»
fo

Digitized by VjOOQ IC

520 GASOLINE AUTOMOBILES

varying from 11£ to 16 inches, serves as the bottom flange of the
frame, and is therefore of Z-section. The vertical section of the frame
is 10 inches high, and has height enough to replace the running board
fenders without appearing narrow. At the front and rear ends of the
frame, the running boards are curved upward, strengthening the frame

Fig. 381. Marmon Aluminum Frame, Showing Running Board Construction

as well as supporting the fenders into which they merge. The frame,
beyond these points, both forward and rearward, is made of channel
section of the conventional type. The rear of the frame is 45 inches
wide and tapers to 30 inches at the front spring hangers. The great
depth of the frame section makes it very stiff, so that the body sills

Fig. 382. Brush Preased-Steel Frame
Courtesy of Hale and Kdburn Company, Philadelphia, Pennsylvania

can be entirely eliminated, and yet the doors will not work loose or
bind when the top is up or down.

Fig. 382 illustrates a type of frame similar to the Marmon, the
Brush frame, controlled by the Hale and Kilburn Company, of
Philadelphia.

180

Digitized by

Google

GASOLINE AUTOMOBILES

521

Steel Underpans. The underpan has assumed a great deal of
importance in the last two years, for makers have more and more
realized that it is highly important to protect many of the parts from
road dirt, flying stones, water, etc. Designers have, therefore, given

:35s

Fig. 383. Two-Piece Preased-Steel Underpan Used on Winton Cars
Courtety of Winton Motor Car Company, Cleveland, Ohio

considerable attention to its shape, size, and method of attachment.
In some types, it apparently runs underneath both engine and trans-
mission and is made more or less a part of the main frame. There-
fore, its quick removal on the road would be difficult, if not impossible;
yet road accidents sometimes make it necessary for the driver to take
this pan off to get at the lower side of engine, clutch, or gear box.

For this reason, underpans generally resemble more closely that
shown in Fig. 383. This is a side view, showing the semicircular
form of the pans, as well as the two-piece construction. The forward
part under the engine, which would be taken
down fairly often, is held in place by three
spring clips on either side. Lifting these
clips off is only a second's work; in addition,
there is a filler piece in front, helping to make
the pan fairly air-tight. The depth of the
pan increases slightly toward the rear, so as
to form a slope down which liquids will
drain; the rear end is fitted with an upturned
elbow, so that it will not drip until it accu-
mulates a considerable quantity of liquid.
Continual dripping indicates a full charge,
and the pan is drained by turning the elbow

Fig. 3K4. Detail of Spring

and Section of Wintou

Underpan

over.

In Fig. 384, a detail of the arrangement of the pan shown in
Fig. 383 is presented. This indicates both the permanent part of the
underpan, which is attached to the frame, and the removable part,
which is freed by loosening the spring clips shown.

181

Digitized by

Google

182

Digitized by

Google

GASOLINE AUTOMOBILES 523

Commercial-Vehicle Construction. Commercial work, being
rougher, harder, and cheaper work, changes the frame construction
just as it does everything else about the car. In Fig. 385, a
commercial-vehicle frame which brings out this point is shown.
The main sills are 6-inch channels, while all of the other members
are correspondingly large angles and channels. In one place the section
consists of a box shape made up by bolting two large channels together,
with the open sides in. The total overall length is not given, since
this differs according to the variations in the wheel base; but, by a
comparison of the figures given, it is seen that the frame shown is in

FIff. 386. Solid Rear Construction of Locomobile for Tires and Tanks
Courtesy of Locomobile Company of America, Bridgeport, Connecticut

excess of 210 inches long by about 37 inches outside width. This is
about twice the total length of the average small car.

In the bracing and arrangement of the different members, this
frame shows other points of difference, the cross-members, for
instance, being nine in number, not including the two diagonal
cross-members. The longitudinal members, too, are eight in number,
not counting the two diagonals.

Rear-End Changes. The locating of the fuel tank at the rear of
the chassis — a practice that was brought into favor largely through
the introduction of the vacuum system of fuel supply — has resulted
in a number of changes to the rear ends of frames. The placing of
the fuel tank at the rear is not new, and probably it would not have

183

524 GASOLINE AUTOMOBILES

occasioned any change to the rear end of the frame were it not largely
for the fact that the spare tires are now carried at the rear of the
chassis. The tires themselves are not heavy enough to make it

Fig. 387. Sketch of Rear-End Construction of Reo Car

essential to strengthen the rear ends, but the very general use of
carrying the spares inflated on demountable rims has added consid-
erable weight to the rear of the chassis. This weight, coupled with

Fig. 388. Typical Rear-End Construction, Carrying Gasoline Tank

that of a large fuel tank, has compelled makers to give more attention
to the rear construction.

Provision is made for carrying the spare tires on the Locomobile
chassis by means of an apron conforming in shape to the shoe. The
three-quarter elliptic springs of the scroll type have ends attached to
the outside of the main frame, w T hich is carried back and serves as an

184

Google

GASOLINE AUTOMOBILES 525

extension for attaching the fuel tank. A cross-member is also utilized ;
it series as a point of attachment for the two rods supporting the
lower apron and for two upper rods as well. This design has merits
in that the tire carrier is firmly anchored and serves to protect the
fuel tank from injury possible in operating in crowding traffic -where
rear-end collisions are not uncommon. As may be noted, Fig. 386
shows the method of using an upper cross-member to prevent theft
of the tires.

A different type of rear construction is shown in Fig. 387, a Reo.
Here the rear cross-member is gusseted, and a pair of substantial arms
are riveted to the cross-member. These arms serve as an anchorage
for the tire holders which, in turn, have a cro^s-rod for protection.
Still another design is shown in Fig. 388. Here the side rail of the
frame projects back of the rear cross-member of the frame for a dis-
tance of about 12 inches. The fuel tank is suspended from these two
extended frame members by means of steel straps which pass around
the tank.

FRAME TROUBLES AND REPAIRS

The more usual troubles which the repair man will encounter
are sagging in the middle; fracture in the middle at some heavily
loaded point or at some unusually large hole or series of holes;
twisting or other distortion due to accidents; bending or fracture
of a sub-frame or cross-member; bending or fracture at a point
where the frame is turned sharply inward, outward, upward, or
downward.

Sagging. A frame sags in the middle for one of two reasons,
either the original frame was not strong enough to sustain the load
or the frame was strong enough normally, but an abnormal load was
carried, which broke it down. Sometimes a frame which was large
enough originally and which has not been overloaded will fail
through crystallization or, in more common terms, fatigue of the
steel. This occurs so seldom, and then only on very old frames,
that it cannot be classed as a "usual" trouble; moreover, it cannot
be fixed.

When a frame sags in the middle, the amount of the sag deter-
mines the method of repair. For a moderate sag, say J to \ inch,
a good plan is to add truss rods, one on either side. These should
be stout bars, well anchored near the ends of the frame and at points

185

Digitized by

Google

526 GASOLINE AUTOMOBILES

where the frame has not been weakened by excessive drilling. They
should be given a flattened U-shape, with two (or more) uprights
down from the frame between them. The material for them should
be stiff enough and strong enough to withstand bending and should
be firmly fastened to the under side of the frame. The truss rods
should be made in two parts with a turnbuckle to unite them, the
ends being threaded right and left to receive the turnbuckle.
When truss rods are put on a sagged frame, it should be turned
over and loaded on the under side; then the turnbuckles should be
pulled up so as to force the middle or sagged part upward a fraction
of an inch, say J to J inch, and then the frame turned back, the
other parts added, and the whole returned to use. A job of this
kind which takes out the sag so that it does not recur is a job to be

proud of.

Fracture. Many frames
break because too much metal
was drilled out at one place.
Fig. 389 shows a case of this
kind. The two holes were
drilled, one above the other,
for the attachment of some
part, and were made too large.
They were so large that at
this particular point there was
not enough metal left to carry the load, and the frame broke, as indi-
cated, between the two holes and also above and below. A break of
this kind can be repaired in two good ways. The first and simplest,
as well as the least expensive, is to take a piece of frame 10 to 12
inches long, of sufficiently small section to fit tightly inside this one.
Drive it into the inside of the main frame at the break, rivet it in
place firmly throughout its length, and then drill the desired holes
through both thicknesses of metal.

This is not as good as welding. A break of this kind can be
taken to a good autogenous welder who will widen out and clean the
crack, fill it full of new metal, fuse that into intimate contact with the
surrounding metal, and do so neat and clean a piece of work that one
would never know it had been broken. When a welding job is done
on a break like this, and no metal added besides that needed to fill the

186

Digitized by VjOOQlC

Fig. 389. Reboring Cracked Steel Channel

GASOLINE AUTOMOBILES 527

crack, subsequent drilling should be at an angle, to avoid a repetition
of the overloading condition. In the figure, the dotted lines suggest
the drilling. By staggering the holes in this way, there is a greater
amount of metal to resist breakage than would be the case with one
hole above the other — a method which might preferably have been
used in the first place.

So much welding is done now, and so many people know of its
advantages, that every repair shop of any size should have a weld-
ing outfit.* A frame job is essentially an inside bench job, but a
large number of cases of welding could be done directly on the car
outside the building, particularly in summer when the outside air
and cooling breezes are desirable. So, it is well to construct a small
truck on which to keep the
oxygen tank, acetylene cylin-
der, nozzle for working, and a
fire extinguisher. One form
of a truck is shown in Fig.
390. This truck is a simple
rectangular platform with
casters, a handle, and a rack
to hold the tanks. It saves
many steps and is particu-
larly convenient in summer
months. This outfit is essen-
tially a home-made affair, but „ ^ TT . ^ 4 A ,

J m ' Fig. 300. Handy Oxy-Acetylene Outfit

the gas-welding and electric-
welding manufacturing companies have designed small outfits espe-
cially for automobile repair work, which would be preferable to the one
in Fig. 390, especially where the amount of repair work warrants a
reasonable expenditure for a welding outfit. A description of both gas
and electric outfits and instructions for their use are given in the
section on Oxy-acetylene Welding Practice.

Riveting Frames. Tightening Rivets. Rivets securing the cor-
ners of a frame or holding cross-members, gussets, and plates often
work loose, particularly with the flexible type of frame previously
alluded to. The location of the rivet and the accessibility of the part
will determine how best to proceed with the work. The chief trouble
experienced is that of placing a sufficiently solid article against the rivet

187

Digitized by

Google

528

GASOLINE AUTOMOBILES

while the other end is being hammered. As a rule, old axles, sledges,
and hammers will serve under ordinary conditions, but these cannot
always be used in a channel frame. One method is to employ an old
anvil which is turned upside down and so placed in the frame that the
flat end of the anvil is placed against the head of the rivet, while a rivet
set is employed to set the rivet up snug. The horn of the anvil is
allowed to rest on the other side of the frame. This method can be
used for cutting off rivets as well as for tightening old ones. The anvil
should be of sufficient length to rest on the frame as above described.
When an anvil is not available, the following method may be used
with success. Take a i-inch bolt and cut it off so that it will just go
in the frame between the rivets. Slightly countersink the head of the
bolt with a cold chisel. Put on the nut and slip in between the rivets
and run the nut down until it expands tight in the frame. The
depression in the head of the bolt, and the nut fitting around the oppo-
site rivet head will keep

2^ ^a^

Fig. 391. Method of Riveting Frame

r „ it firmly in place while

v O c ^T £y L- i^^^ lScyi riveting. It is not always

^— - — — ' ' l^n T ^i 'in ii * ■■■•«■■■• practical to attempt to

tighten a rivet. The bet-
ter method is to remove
it, drill a larger hole and use a larger size rivet. Rivets are usually
made of Norway iron. Heat to a red heat before using.

Riveting Methods. There are two methods of riveting, the driving
in and the backing in. The latter method is shown in Fig. 391, and
the two plates to be riveted are drilled in the usual manner, as shown
at A, with the rivets a trifle smaller than the hole, placed as shown
at B. With hot riveting, the hole should be about & inch larger than
the rivet, but with cold rivets, the opening should be such that the
rivets will slide in. Instead of backing up the head of the rivet, a
dolly is applied to the small end, as indicated at C, and the driving
is done on the head of the rivet by a set D and a hammer. The
energy of the hammer is applied through the set to the rivet, which is
upset or enlarged, as it is unable to move because of the mass of metal
in the dolly. The metal of the rivets expands sidewise at A and B,
completely filling the space. A feature of this method is that a part
of the hammer blow is expended in forcing the plate N into contact
with the plate 0. The metal at B is prevented from moving sidewise

188

Digitized by

Google

GASOLINE AUTOMOBILES

529

by a head formed at the dolly end of the rivet, and additional blows of
the hammer tend to bring the plates closer and to hold them. The
backing-in method is practical in making the various styles of rivet
heads, particularly in making the thin, almost flush, head, and an
advantage is that there
are no reactionary
stresses upon the thin
head as would exist with
the driven-in rivet.

As there is more
demanded of the rivet
replacing the old mem-
ber, it is important that
the work be carefully
performed. This applies
to the holes in the plate.
All sharp corners should
be removed, as they af-
ford an opportunity for the rivet to shear off by external stress
or to fly off under internal strain. A reamer, drill, or countersink
can be used in removing sharp corners. The face left need not be
more than tt or ^r inch wide, in order to greatly strengthen the rivet
at its weakest point, or where the head joins the body. By slightly

Fig. 392. Adding a Truss Rod to the Front of a Weak or

Damaged Frame to Strengthen It and Preserve

the Radiator

Ay/rcfar-e

^a// trr-srt of
sAf+rrrig gear.

^terrf/ng /rrofoj~

JLoo/o

~*JLoojo
Fig. 393. Bracing Fractured Frame with Bar and Turnbuckle

chamfering the corner of the plate, the rivet is given a corresponding
fillet, which not only increases its holding power but serves to draw
the plates together.

Frame Bracing Methods. There are several methods whereby a
frame that has been injured through collision or has sagged because

189

Digitized by

Google

530 GASOLINE AUTOMOBILES

of too light construction can be repaired. The front of the frame is
the chief offender in this respect, and many times a leaking radiator
is the result. When repairs to the radiator fail to cure the trouble, it
may be assumed that the frame is at fault. A simple remedy is
shown in Fig. 392 and consists in bracing the frame by means of a rod
and turnbuckle. The rod should be about 2 inches longer than the
width of the frame and threaded for about 3 inches on each end.
The turnbuckle is not essential, but it simplifies the work. In
installing the brace, the inside nuts are screwed on first and far enough
to allow putting the rod in place. These nuts are next screwed out
until they bear against the frame, and the latter is forced out until
any pressure that may have existed on the radiator is eliminated.
The outside nuts are then screwed up snug. The advantage of the
turnbuckle is that adjustments may be made as required.

Fig. 393 shows a method of trussing a frame that was fractured
by the stresses of the motor starter. Even after the fracture had
been repaired, the driving gear of the starter would not mesh properly
with the ring gear on the flywheel of the engine. As the movement
was up and down on the frame, a truss was found necessary; while it
was a simple matter to attach one end of the truss on the left-hand side
of the chassis, the right-hand side was more difficult because of the
proximity of the ball arm of the steering-gear lever. The problem
was solved by forming a loop at one end of the truss of sufficient width
and length to permit travel of the ball arm. By utilizing a turn-
buckle the desired tension was obtained.

SPRINGS

Basis of Classification. The springs are important components
of the chassis; for while the frame supports the power plant, clutch, and
gearset, it is, in turn, supported upon the springs. The tendency at
present is to design the frame and spring suspension so that the rear
springs are placed very close to the rear wheels. In some cases, the
frame is wide at the rear and is directly over the springs. Springs
may be divided into seven general classes as follows: semi-elliptic,
the full-elliptic, the three-quarter elliptic, the platform type, the
cantilever, the quarter-elliptic, the coil, and combinations of these.
The full-elliptic spring is made up of two sets of flat plates, slightly
bowed away from each other at the center and attached together at

190

Digitized by

Google

GASOLINE AUTOMOBILES

531

the ends. When these are used, the centers of the springs are attached
top and bottom, respectively, to the frame and axle. With half of
the top of the spring cut away, and the cut, or thick, end attached to
the frame, this spring becomes a three-quarter elliptic. When the
whole top of the spring is cut away, so that the spring is but a series
of flat plates, bowed to a long radius, this becomes a semi-elliptic
spring. By turning the semi-elliptic spring over, it becomes a canti-

Fig. 394. Typical Semi-Elliptic Front Spring

lever when its center and one end are attached and the load applied
to the other end. The quarter-elliptic is but a quarter of a spring,
while the platform consists of three semi-elliptics — two as side mem-
bers in the regular position, while the third is used as a cross-spring,
being inverted and attached at the center to the rear end of the frame
and at its ends to the side members. The coil form requires no expla-
nation and is not now used on cars. In addition, these forms are
modified by scroll ends and various attachments.

Fig. 305. Typical Full-Elliptic Front or Rear Spring

Semi-Elliptic. Fig. 394 shows a front spring of the semi-elliptic
type, the form which is used now for almost every front spring.
This is a working spring of the usual type, fixed at the front end,
shackled at the rear end, attached to the axle in two places, and with
two rebound clips in addition. The latter are put on the springs
to prevent them from rebounding too far, in the case of a very deep
drop. In some cases, as high as four, six, or eight of these clips may

191

Digitized by

Google

532

GASOLINE AUTOMOBILES

be used. Many other springs are made with ears, these being clipped
over the next lower spring plate, the final result being the same as the
use of many clips, but with improved appearance.

Full-Elliptic. Full-elliptic springs are the oldest form known.
Fig. 395 shows the construction of this type, the upper and lower parts
being pivotally connected at the ends. A slight modification of this
form, known as the scroll-end full-elliptic type, is in more extensive

Fig. 396. Full-Elliptic Spring with Scroll Ends

use than the full-elliptic plain type. As Fig. 396 shows, the ends of the
upper leaves are bent over. Each carries an eye, which is connected to
the eye in the end of the upper leaves of the lower half of the spring by
means of a shackle. This construction makes a very soft-riding spring.
Three-Quarter Elliptic. Very much like Fig. 396 is the form
known as the three-quarter elliptic spring, the one having scroll ends
being shown in Fig. 397. This form of spring is fastened at three

Fig. 397. Three-Quurter Elliptic Rear Spring with Scroll Ends

points. The lower part of the spring is shackled at the front end,
fixed to the axle at the center, and shackled to the upper part of the
spring at the rear. The upper part of the spring is fixed to the frame at
the upper front end and shackled to the lower part at the rear. Fig. 407
shows another example of the three-quarter elliptic spring, which may
differ in practice, as some three-quarter springs are not scroll ended.
This form of spring is growing in favor daily, a greater number
being used this year than last, while designs for next year show a still

192

Digitized by

Google

GASOLINE AUTOMOBILES 533

greater increase. One reason for this increase is the great increase in
the number of dropped frames, that is, frames unswept at the rear. To
this form of frame, the three-quarter elliptic spring is very well adapted
and makes a very natural,very good, and very easy-riding combination.
Platform. The platform type of spring is. used a great deal on
large cars, as well as on very heavy trucks, on account of its ability
to carry heavy loads well, and also on account of its flexibility.
As may be seen in Fig. 398, it consists of three semi-elliptic springs
shackled together at the corners. The rear cross-spring is usually
made shorter than the two side springs, while the latter are set off
center, making the front of the spring, that is, the part forward of
the point of attachment to the axle longer than the part to the rear.
There are two reasons for this: First, the front end acts somewhat
as a radius rod, the rear end of the frame rising in an arc of a circle
whose radius is the front half of the spring; second, this plan dis-

Fig. 398. Platform Springs, Showing How Side- and Crose-SpringB Are Shackled Together

tributes the spring action equally in front of and back of the axle.
Since the rear cross-spring is fastened to the frame in the center,
each half of it is considered as a part of the side spring to which it is
shackled. Thus, the total length of the side spring in front of the
axle is the measured length of the side spring, while the total length
of the side spring back of the axle is considered as the side length
plus half of the cross-spring length. The center point, or point of
axle attachment, is not moved so far forward as to make these two
lengths equal, but in a proportion which may be derived thus : Assume
a side spring 42 inches long and a cross-spring 35 inches long; then the
spring would be set out of center some 4J inches, making the front
length about 25£ inches, while the rear length would be 16£ inches plus
half of the rear spring, or 17 \ inches, making a total of 34 inches.
This would give a ratio of 25 J to 34, or 1 to 1.333. If the side mem-
bers were 50 inches, the ratio would be about 1 to 1.25, and for side
members shorter than 42, the ratio would be about 1 to 1 .5.

193

Digitized by

Google

534 GASOLINE AUTOMOBILES

Cantilever. The cantilever is, in appearance, a semi-elliptic
spring turned over. It gets its name, however, from the method of
suspension, which is quite different from that of any form of semi-
elliptic spring. Moreover, as a part of this suspension, at least one

Fig. 399. Cantilever Rear Spring Used on King Can
Courtesy of King Motor Car Company, Detroit, Michigan

end of the cantilever and sometimes two are finished up flat and
square to slide back and forth in a groove provided for that purpose, a
bolt through a central hole preventing the spring from coming out of
its guide. One form, shown in Fig. 399, has a fixed attachment
to the rear axle, a pivoted attachment to the frame at its center

Fig. 400. Front End of Cantilever Spring on Siddeley-Deasy (Engiiah) Car

(or slightly beyond the center), and a sliding attachment to the frame
at its forward end to take care of the increase in' length and of the
forward movement necessary w T hen the rear wheels rise.

Another form of cantilever is that shown in Fig. 400. This is
the rear spring on the Siddeley-Deasy (English) car and, like that of

Digitized by VjOOQIC

GASOLINE AUTOMOBILES 535

the King, is pivotally mounted on the frame just forward of its center.
Unlike the King, however, the forward end of the spring has a shackle
which permits it to swing when the rear axle rises or falls. This
shackle is a very interesting feature of this installation, having an
adjustment which is most unusual for a shackle, Fig. 401 . Note how the
outsides of the shackle
have a series of grooves,
into which the head of
the shackle bolt on one
side and the washer on
the other, fit. By setting
these in the desired
grooves and tightening
the nut, the position is
fixed. If this does not
give the proper throw, it
is a simple matter to re-
move the nut and make

a new adjustment. p^ 401 Detail of the Adj^t^ shackle on Siddeley

In France, a form Of Cantilever Spring

double cantilever has been tried out with success; this form consists of
a pair of cantilevers, one above the other, separated at the center by a
carefully sized spacing block, which is pivotally attached to the frame.
The rear ends are attached above and below the axle, while the front

ends are attached to two fixed points. Although the ends are made
much thinner and more flexible than those just shown, it should be
noted that both of them are fixed. The rise and fall of the wheels
must be taken up by the springs themselves, the pivot in the center
simply distributing the distortion over both the front and rear halves.

195

Digitized by

Google

536 GASOLINE AUTOMOBILES

Advantages of Cantilever. The advantages of the cantilever
spring are the smaller unsprung weight and the reduced manufac-
turing cost for a given amount of flexibility. Another advantage is
the absence of sharp rebounds and a greater deflection for a given
load and length of spring; it also obviates the cut in the body required
with the three-quarter elliptic spring. When the cantilever takes the
driving strain, the main leaf is usually stiffened and, being stronger
sidewise, it eliminates a good deal of the side sway. With torque
rods, the main lead may be made lighter, as the starting, the braking,

Fig. 403. Unique Rear Spring of Marmon Cars

and the torque act through the torque rods. Since there is more
metal in the line to the thrust, they are especially suitable for taking
the thrust, and not quite as efficient in taking the torque.

Hotchkiss Drive. The adoption in 1915 of the Hotchkiss drive,
Fig. 402, in which the rear axle is connected with the frame through
the chassis springs only, making the springs perform the functions of
torque and thrust, is a radical departure from previous forms. The
objection that it subjected the springs to unnecessary strains has not
been sustained in practice, which has shown that a slight yielding of
the rear axle when starting and braking, by a certain flexure in the
springs, has reduced the stresses upon the transmission members.

Digitized by CjOOQIC

GASOLINE AUTOMOBILES

537

In the Hotchkiss drive, the springs are rigidly attached to the rear
axle, while the front end of the spring is secured to the frame with a
proportionately large bolt through which the drive is transmitted.
Users of the drive claim that it is quieter, that the car holds the road
better, that it is more flexible, and that it avoids the road shocks
which are transmitted through stiff torque members from the axle
to the frame. Makers who drive through the springs and employ
other torque members claim that they are not sacrificing flexibility in
driving while eliminating a certain side sway and other strains preva-

Fig. 404. Combination Cantilever and Semi-Elliptic Spring on Tractor

lent when the springs perform the functions of the torque. In the
Hotchkiss drive, two universal joints in the drive shaft are used.

Unconventional Types. Marmon. A departure from conven-
tional practice is the spring used on the Marmon car and shown in
Fig. 403. It is a double-transverse construction, consisting of semi-
elliptic springs bolted together at the center, with a curved block, or
hard-maple cam, between them. This cam varies their stiffness,
the spring automatically becoming stiffer as the load increases.
Under normal load, the stiffness is about 170 pounds per inch, but as
the springs are compressed the stiffness will reach 400 pounds. They

197

Digitized by

Google

538

GASOLINE AUTOMOBILES

are shackled at one side and fixed at the other, obtaining a perfectly
parallel motion to the frame. There is said to be no roll as is some-
times found with transverse springs.

Knox Tractor. An unusual method of suspension is that
employed on the Knox tractor, a combination of a cantilever and
semi-elliptic spring at the rear end of the frame. The design shown in

Fig. 405. Rear Spring of Six-Ton Truck

Fig. 404 includes heavy semi-elliptic springs, which are attached to
the rear axle by long clips and carry the fifth wheel of the trailer.
There is no connection between the springs and the tractor frame, so
they carry the weight of the trailer and load only. The tractor frame
is mounted on a cantilever spring having a pivot near its center and a
shackle at the front end. The rear end bears on a seat clipped to the
rear axle. This obtains a flexible mounting for the tractor and also
permits the carrying of very heavy loads on the trailej* .

Fig. 406. Special Semi-Elliptic Rear Springs Formerly Made for Winton Care
Courtesy of Perfection Spring Company, Cleveland, Ohio

Semi-Elliptic Truck Spring. The semi-elliptic spring is a favorite
with makers of commercial vehicles. It is simple, and if the length,
width, and other dimensions are proportioned correctly, it is a most
satisfactory method for both front and rear suspension. Fig. 405
shows a rear spring for a 6-ton truck, the method of shackling, and
how it is mounted on the axle by means of a spring seat.

198

Digitized by

Google

GASOLINE AUTOMOBILES 539

Winton. Many makers use their own special form of springs.
Fig. 406 shows the spring formerly used on the Winton cars, a type
which might be described as a double-purpose spring. It was made
in two parts, the lower part consisting of a regular semi-elliptic flat
spring, while the upper part was a semi-elliptic flat spring with scroll
ends. The central part of the spring was treated as one, being
attached to the axle in the usual manner; the ends, however, had a
peculiar appearance, because the upper and lower halves of the spring
were of different shape. The scroll end of the upper part was sup-
posed in itself to absorb many of the small road shocks. The spring
was loosely attached to the frame at each end by means of a double

shackle, made necessary by the double action of the spring; the tend-
ency to flatten out increased its length, thus calling for a forward
motion of the front and a backward motion of the rear ends, while the
different lengthening action, owing to the difference in the lengths of
the two parts of the spring itself, resulted in a turning about a different
point.

For comparison with this earlier Winton spring, the latest form
is shown in Fig. 407. It will be seen that the three-quarter elliptic
form has been adopted, with a kick-up at the rear end of the frame.
If the two types are compared somewhat closely, it will be seen that
the only change in the frame part is the kick-up. The new springs
show the scroll ends to which Winton has always been partial.

199

Digitized by

Google

540 GASOLINE AUTOMOBILES

Ford. The form of the Ford spring has always been distinctly
different. Fig. 408 shows the front and Fig. 409 the rear spring used
on Ford cars, the distinction in the front spring being principally
in the use of a single ordinary inverted front spring set across the
frame on top of the axle, where most makers use a pair of side springs
set parallel to the frame. This form is simple and cheap to make
and assemble, the cost of the spring itself, and the work of putting

Fig. 408. Special Vanadium Front Springs for Ford Care
Courtesy of Ford Motor Company, Detroit, Michigan

it on being just about half that of the spring attachment of the
ordinary two-spring type. On the other hand, excellent riding quali-
ties are claimed for it. A second distinction is that the spring is
an inversion of the usual semi-elliptic type, the set of the spring
being downward instead of upward. A third claim to distinction is
in the use of vanadium steel, which, it is claimed, has a higher tensile
and compressive strength than any other steel, and it is practically
unbreakable in torsion. This steel is also being used in many other

Fig. 409. Rear Springs of the Ford Car

parts, such as crankshafts, camshafts, fender irons, frames, drive-
shafts, etc., resulting in a very light-weight car, since the greater
strength of the material allows the use of smaller sections for equiva-
lent strength.

The Ford rear spring has all the claims to distinction of the
front spring, and, in addition, a hump at the center. Fig. 400 shows
this hump clearly, the rear-frame cross-member being only partly
shown. It will be noted that both ends of both springs are shackled,

200

Digitized by

Google

GASOLINE AUTOMOBILES 541

the construction necessitating it. These springs represent quite a
radical departure, the success of which has been proved in actual
practice.

Locomobile. Fig. 410 shows the three-quarter scroll elliptic rear
spring used on the Locomobile, also the method of shackling both ends

Fig. 410. Three-Quarter Scroll Elliptic Spring Used on Locomobile Care

of the spring, and the use of a considerable extension beyond the spring
clip of the two upper leaves. Fig. 411 illustrates the Locomobile
front springs, the upper spring being used on the 1916 model, and the
lower one on the 1917 model. As may be noted, the later type is
2 inches longer and also flatter, and the distance between the spring

Fig. 411. Two Seta of Front-Axle Springs on Locomobile Cars

bolt and eye of the shackle is less in proportion to the 1916 design. It
was found that the jerky action and fore-and-aft pitching of the axle
were eliminated by this construction, greatly improving the riding
qualities of the vehicle/

Electric Car Springs. The spring suspension of electric pleasure
cars is similar to that of the gasoline vehicle, semi-elliptic suspension

201

Digitized by

Google

542 GASOLINE AUTOMOBILES

in front, and full-elliptic scroll-end suspension at the 1 rear. The
method of shackling is similar.

Varying Methods of Attaching Springs. Springs are attached
in many ways. For example, the one shown in Fig. 398 might be
shackled at the front end, fixed to the axle, and fixed to the center
of the frame at the rear, the side and cross-springs being shackled
together. Again, the front end might be fixed to the frame, Fig. 412,
all other connections being unchanged. Or, with either method of
fixing the front end, the spring might be swiveled on the axle, so as
to be free to give sidewise without changing the other properties of
the spring. Or, with either method of fixing the front end of the
spring, and with or without the axle swivel, the cross-spring might
be pivoted at the central point so as to be free to turn in any direction

Fig. 412. Special Type of Double Quarter-Elliptic Rear Spring

about this central point. This fatter method prevents binding and
unequal spring action when one side of the frame is unduly raised
or depressed, the solid method of fixing the rear end resulting in a
double action on the part of one spring, owing partly to the tilting of
the body and partly to spring action itself. With the pivot joint, the
spring first swings about this point until a position of equilibrium is
established, when the suppleness of the spf ing comes into action, the
result being a deflection of half what it would be in the other case.

This form of spring also is used with the spiral spring, the
latter taking the place of the shackle between the side and rear
members. In this position it serves two purposes: (1) as a
connector, taking the place of and doing the work of a shackle,
thus acting as a universal and swinging joint between the two
springs; (2) as a shock absorber, taking up road shocks within

Digitized by

Google

GASOLINE AUTOMOBILES 543

its length, that is, in the coils, without transferring any of them to
the body proper or, in case of heavier shocks, sharing with the side
and rear springs. This, of course, is the true function of the
springs — to allow the road wheels to pass over the inequalities,
rising and falling as may be necessary, while the body travels along
in a straight line, level and parallel with the general course of the road.
Under slinging. Almost any of the spring forms shown and
described may be underslung, that is, attached to the axle from
below. This is a quite common practice for semi-elliptic springs when
used in the rear, but it is very uncommon for front springs. Similarly,
full elliptics, whether having scroll ends or not, are frequently Mlder-

Fig. 413. Re&r-Spring Arrangement on 1917 Premier

slung. The three-quarter elliptic form when used in the rear is
usually underslung; the platform spring is not underslung so often.
The cantilever and quarter-elliptic springs have been mentioned in
connection with the underneath attachment. It should be pointed
out that the position beneath the axle lowers the center of gravity by
an amount equal to the thickness of the spring plus the diameter of
the axle plus twice the thickness of the attaching means, and this, too,
without interfering with the quality or quantity of the spring action.
In the case of the cantilever, the effect of underslinging is to reduce the
straightness of the spring, that is, the form when attached above
the axle is almost straight, while the form when fastened below the
axle is very much curvea- has considerable "opening".

203

Digitized by

Google

544 GASOLINE AUTOMOBILES

Shackles and Spring Horns. Considerable improvement has
taken place in the method of shackling springs, and provision is now
made with some types of springs for the adjustment of the shackles
and hangers as well as for renewing bushings. Reference has been
made to the tendency of design in rear-spring suspension and to the
underslung types. Fig. 413 shows the design employed with the 1917
Premier, and, as may be noted, the springs are slightly diagonal, the
front ends coming inside the frame line, while the rearends are attached
to goose necks of a rear extension of the frame pieces. Shackles are
used for connecting the ends of the springs to the extensions.

A departure from the conventional shackle is the safety double
shackle used on the Rainer 1000-pound capacity delivery car, shown
in Fig. 414. In addition to the main eye on the main leaf of the rear

spring, the second leaf is extended
and formed into an elongated eye,
allowance being made for deflection
under load. The eye of the leaf is
attached to the frame by the usual
rigid spring bolt. Additional means
of support are furnished by clamps
on either side of the spring, one by a
pin through the elongated eye, and
Fig. 4i4. Double shackle Used on Rainer the other by a pin through the lower
Delivery Car en( j Q j ^ e clamp which takes in the

third and fourth leaves. It is pointed out that in case the main leaf
breaks the eye of the second becomes the driving eye, and should
this break, the spring will wedge between the under pin and the
upper part of the clamp, thus obtaining rigidity which is essential
with the Hotchkiss method of drive.

Although the general practice is to shackle the semi-elliptic front
spring at its rear, a departure which places the shackle at the spring
horn or in front is noted in the Manly truck.

Adjusting Spring Hangers. The type of front-spring hanger,
shown in Fig. 415, is adjustable. This adjustability is accomplished
by relieving the body of the grease cup and screwing in the slotted
bolt which eliminates side play. The grease cup body acts as a lock
nut. The rear hanger of the front spring, Fig. 416, is adjusted by
loosening the inside lock nut and the body of the grease cup. After

204

Digitized by

Google

GASOLINE AUTOMOBILES

545

removing the cap of the grease cup, the hanger bolt is turned out, or
to the left, with a screwdriver, decreasing the distance between the
links. The grease-cup body and lock nut are then set up tight.

Fig. 415. Section of Adjustable Front-Spring Hanger

Provision is made with some types of rear springs for eliminating
play when the rear ends are mounted on seats.

Spring Lubrication. All springs now are fairly well lubricated.
All shackles are provided with grease cups, and other points of attach-
ment to the frame are provided with oil holes. Where the springs are
pivoted either on frame or axle, a big grease cup is usually furnished.
Jn addition, it is now realized that the maker can prevent much of
the noise formerly coming
from dry and perhaps rusted
steel spring plates working
over each other. There are
several ways in. which oiling
is accomplished. The springs
are made with an internal
lip, or groove, which is filled
with lubricant when they are
assembled; or between each
pair of spring leaves is placed
an insert having a series of oil pockets throughout its length, each
filled with lubricant normally held in by means of a membrane cover;
the movement of the spring plates and the heat generated thereby

Fig. 416. Section of Rear-Spring Hanger

205

Digitized by

Google

546 GASOLINE AUTOMOBILES

starts the lubricant flowing to all parts. An even later method is
the attachment of external cups, provided with a wick which goes
around the spring leaves and is pressed against their sides. The
wick is kept wet with lubricant from the cups, and the motion of
the spring leaves, together with the capillary action in the wick,
draws the oil in between the leaves.

Spring Construction and Materials. A study of the illustrations
used will show that practically all modern springs are clipped together,
the number of these clips varying with the length of the spring and the
use to which it will be subjected. Thus, Winton, Fig. 407, shows
three clips and a band. Some springs show as many as five clips and
two bands. But none indicate the use of spring ears — very small pro-
jections on the ends of the leaves — which are bent over the edge of the
leaf next below it to assist in holding the spring together, but they
are in quite general use. Altogether, there are about 14 or 15 forms
of spring-leaf ends, but those in general use may be reduced to seven.
These are: the oval ; the round point; the short French point, a modi-
fication of the oval; the round end with slot and bead; the ribbed
form, widely used on motor trucks; the square point tapered; and
the diamond point.

In addition, sizes have been standardized in America to the
extent that only five widths are used for pleasure cars and seven for
motor trucks. Those for the former are: 1£, If, 2, 2}, and 2\ inches;
for the latter: 2, 2\ y 2£, 3, 3§, 4, and 4£ inches.

As the automobile business has called for better stand-up
qualities under more severe conditions of use, the quality of steel
used has been greatly improved, and other materials are better. The
French make excellent springs, many of our best automobile manu-
facturers going abroad for their springs for this reason, but American
springs are improving in quality so rapidly that this is becoming
unnecessary. Formerly, all springs were of a plain carbon stock, but
now a great deal of silicon, manganese, and vanadium steel are being
used. Some chrome and chrome-nickel steel have also been tried.

SPRING TROUBLES AND REMEDIES

Usual Spring Troubles. Lubrication. The average repair man
is likely to have more call to lubricate the leaves of a spring than any
other one thing in connection with springs. True, they lose their

206

Digitized by

Google

GASOLINE AUTOMOBILES

547

temper; they sag and show signs of losing their set; plates break in the
middle, at the bolt hole, and near the ends of the top plate; and inside
plates break in odd places. But more frequently the springs make an
annoying noise, a perceptible squeak, because the plates have become
dry and need lubricating. When this happens, and the up or down
movement of the car rubs the plates over each other, dry metal is
forcibly drawn over other dry metal with which it is held in close
contact; naturally, a noise occurs.

To lubricate the spring, it is well to construct a spring-leaf
spreader. Of course, the job is best done by jacking up the frame,
dismounting the spring entirely, taking it apart and greasing each
side of each plate thoroughly with a good graphite grease, then

Fig. 417. Handy Tools for Spreading Spring Leaves to Insert Lubricant

reassembling it, and putting it back under the car. This is the best
way, but it costs the most, and few people will have it done. Some-
times spring inserts are used; these are thin sheets of metal of the
width and length of the spring plates, having holes filled with lubri-
cant over which is a porous membrane.

For the ordinary spreading job, the plates must be pried apart
and the grease inserted with a thin blade of steel, for instance, a
long-bladed knife. To spread the leaves, jack up the frame so as
to take off the load, then insert a thin point and force it between a
pair of leaves. In Fig. 417, two forms of tools for making this forcible
separation are shown. The first is a solid one-piece forging with
the edges hardened. It is used by sliding the edges over the ends
of the spring leaf, then giving it a twist to force it in between them,

207

Digitized by

Google

548 GASOLINE AUTOMOBILES

as shown in the figures. The second tool is intended to be forced
between two plates by drawing back on the handle.

Tempering or Resetting Springs. When springs lose their
temper or require resetting, it is better for the average repair man
to take them to a spring maker. Tempering springs is a difficult job,
as it requires more than ordinary knowledge of springs, their manufac-
ture, hardening, annealing, etc. When springs are in this condition,
they sag down under load and have no resiliency. If a great many
springs are handled, a rack like that shown in Fig. 418 is well worth
making.

Broken Springs. When springs break, there is but one shop
remedy — a new plate or plates. But when they break on the road,
it is necessary to get home. When the top plate breaks near the

Fig. 418. Simple and Well-Designed Spring Rack

shackled end, repair this sufficiently to get home by using $ flat wide
bar with a hole in one end big enough to take the shackle bolt; bolt
this bar to the spring in place of the end of the leaf which is broken.

General Hints on Spring Repairs. As a rule, a break in a plate
takes place where it does not prevent operating the vehicle, but it
should be borne in mind that the damage to the plate subjects the
other plates to extra work, and, unless the broken member be properly
repaired or replaced, the others are likely to break. If one of the
intermediate plates breaks in the center at the bolt, tighten the spring
clips as much as possible. Very frequently the rebound clips will be
found to be loose, and missing clips also contribute to spring breakage.

The removal of a plate from or addition to a set is very likely to
upset the grading of the construction. It is not practical to replace a
broken plate with a new one because it is of the same width and thick-
Digitized by VjOOQIC

GASOLINE AUTOMOBILES 549

ness, but an expert spring maker should be called in to see that the set,
or fit, is correct. The fitting of a leaf requires the services of an
expert spring man; while it appears to be a simple matter, the lack
of knowledge by some claiming to be spring experts is responsible for
breakage after the spring has been repaired. The spring clips and the
nut of the center bolt should be kept tight. The importance of
preventing the accumulation of rust on the leaves and of lubrication
has been commented upon.

SHOCK ABSORBERS

Function. The ordinary flat-leaf springs of any of the types
previously described are inadequate for automobile suspensions.
When the springs are made sufficiently stiff to carry the load properly
over the small inequalities of ordinary roads, they are too stiff to
respond readily to the larger bumps. The result is a shock, or jounce,
to the passengers. When the springs are made lighter and more
flexible in order to minimize the larger shocks, the smaller ones have
too large an influence, thus keeping the body and its passengers in
motion all the time. These two contradictory conditions have created
the field for the shock absorber.

The shock absorber is generally a form of auxiliary spring, the
function of which is to absorb the larger shocks, leaving the main
springs to carry the ordinary Small recoils in the usual manner; in
short, to lengthen the period of shock. This is done in a variety of
ways, and, as might be expected, by a great variety of devices.

General Classes of Absorbers. The simplest forms of absorbers
are the ordinary bumper, or buffer, of rubber and the simple endless
belt, or strap, encircling the axle and some part of the frame and
acting as the rubber pad does — simply as a buffer. There are the
following classes of the more complicated shock-preventing and shock-
absorbing devices: (1) frictional-plate or cam, in which the rotation of a
pair of flat plates pressed together tightly — one attached to the frame,
the other to the axle — opposes any quick movement of the two or of
either one relative to the other; (2) a coil spring used alone and in
combination — alone it is used in the plane of the coil, or at right
angles to it, and parallel to the center line about which the coil is
wound, while in combination it is found joined with the simple leather
strap or with another coil spring of equal or sometimes of less

209

Digitized by

Google

550 GASOLINE AUTOMOBILES

strength, in the latter case the weaker one acting with the main
springs; (3) the flat-leaf spring, a more simple description of whicli
would be a small duplicate of the main semi-elliptic spring set on it so
as to oppose its action; (4) the air cushion; and (5) the liquid device,
in simple form and in combination w r ith some one or more of the coil-
spring forms.

Frictional-Plate Type. A frictional-plate type of shock absorber
is shown in Fig. 419. This absorber consists of an upper arm attached
to the framt, having at its outer end a frictional plate in contact with a
similar plate at the upper and outer end of the other arm pivoted to

the axle. The two plates are
pressed together by means of the
nut shown in the center; this nut
is resisted by the spring beneath
it and the slightly arched surfaces
of the plates. When a sudden
bump raises the axle, it must
turn the two faces of metal across
each other to the limit before it
can lift the body. As will be
seen, this means a considerable
distance, and it can be made
relatively greater by clamping the
nut up tighter, thus increasing the
friction between the surfaces, and,
Fig. 419. Hartford Governed Friction Type therefore, requiring greater force

of Shock Absorber too

Courtesy of Hartford Suspension Company, to tUHl them. Because of this

Jersey CUy, New Jersey . .

adjustable quantity of friction,
this type is called the governed friction type.

When cams are used, practically the same result is obtained,
except that the device is necessarily more complicated. The cam
action usually generates some heat, and, for this reason, this form
of shock absorber is most always enclosed, and the interior, where
the cam works, is filled with grease or very heavy oil.

A modification of the plain frictional-plate form is seen in Fig.
420, which is called a passive range absorber, because, for ordinary
movements of the springs to which it is attached, it does not come into
action. When the usual spring action is exceeded, however, as in a

210

Digitized by

Google

GASOLINE AUTOMOBILES

551

Fig. 420.

Laporte Passive Range Friction Type of
Shock Absorber
Courtesy of Charles Laporte, Detroit, Michigan

sharp jounce, the device becomes effective. It appears much like the
Hartford just shown, but the construction is decidedly different.
The upper, or frame, arm is threaded to receive an Acme-threaded
screw, which is carried by the lower, or axle, arm. The action of
screwing this out tends
to force the plate on the
lower arm, which must
move outward with the
screw against a rubber
washer held firmly by the
outside nut and cover
plate. Thus, the scissors
action of the two arms
on a sudden movement is
resisted by the compres-
sion of the rubber washer.
This compression can be
increased or decreased by tightening or loosening the slotted outside
nut, so that the screw is given less or more movement. The rubber
washer is made with a series of holes in it to allow of compression.
Coil Springs, Alone and in Combinations. Springs AUme.
The coil-spring absorber is probably the most widely used form,
primarily because
both go<
furthermore

and adds little weight. |] ^^ %

In most instances, the ^_ „_J!

coil is so placed as to

compress along the direc- -^

tion of its center line. "Sffr.:

One device, however, the

Acme, shown in Fig. 421, Fig. 421

works at right angles to

this. It consists of a pair

of coils, the two ends of each being so constructed as to go on the

ends of the shackle bolts in place of the usual shackle. When the

shackle is removed, one pair of ends is fastened to the spring in

place of the shackle, while the other pair of ends is fixed to the frame

v because it is ~— _-. -.-.^^

jod and cheap; -^ t--'-""j P""-"^

aore, it is simple —-T^^t^Zl^ *^^^^^

ds little weight. !• • *%e*

Acme Torison Spring Fitted to Three-Quarter
Elliptic Gears
Courtesy of Acme Torsion Spring Company,
Boston, Massachusetts

211

Digitized by

Google

552 GASOLINE AUTOMOBILES

or the other part of the spring, as the case may be. Note that this
arrangement brings one of the coils on either side of the main spring

end, extending away from
it in a horizontal plane. In
this position, the torsion
spring acts as a spring
shackle, absorbing the
jounces and bounces so that
they do not reach either the
body, the attaching point,
or the other half of the
spring, as the case may be.
Fig. 422 is a simple
coil spring of barrel shape,
that is, the end coils are
smaller than those in the
Fig 422 fe^olTruc P u^ to Very <*rt™ a^ are set between

Courtesy of J. //. Soger Company, Roche*Ur, New York frame and axle in SUCh a

way that they absorb the jounces directly.
This is probably the simplest possible
shock-preventing device, consisting only of
the spring and its top frame and bottom
axle connections. These are made in four
sizes of wire, varying from A inch up
to H inch.

In the K-W road smoother, shown in
Fig. 423, the action of the spring is opposed
by an air chamber at the top, creating a
balance. A shock which causes the spring
to move is opposed by the spring itself,
while the rebound, or reaction, is opposed
by the air compressed in the air chamber.

Combinations. Probably exceeded in

simplicity only by the two forms just shown

is the type in which a coil spring and leather

Fi«. 423. k-w spring Type of band, or strap, are combined. One of these,

the Hoover, is shown in Fig. 424. It will be

seen that the spring end is fastened to the body, while the strap is

212

Digitized by

Google

GASOLINE AUTOMOBILES 553

attached to the lower end of the spring and encircles the axle. Hence,
this will not interfere with upward movements of the axle, but
only with the downward ones, that is, the axle is free to rise, but as
soon as the car body starts to rise, the
strap-spring combination acts to prevent
it. This is particularly true if the axle
has reached the limit of its motion and
has started downward before the body
starts upward. In that case, the body
can move upward only the amount of
slack in the strap plus the give of the
spring, but minus the amount the axle
has already moved downward. This inex-
pensive arrangement has found great

favor On Small Cars. Fig. 424. Hoover Shock Absorber,

n 11 a .1 o • rp T • a Spring and Strap Combination

VoiWle-Loil Opnng lypeS. In pnn- Courtesy of H. W. Hoover Company,

. 1 ,1 • . . . . ,./» New Berlin, Ohio

ciple, the use of two springs is not differ-
ent from the use of one. For structural reasons, however, it is easier
to attach the two-spring form, while dividing the load up into two
parts allows of the use of
smaller diameters and smaller
sizes of wire, thus making the
device appear more compact.
One of the two-spring forms,
the J.H.S., is shown in Fig.
425. It consists of a pair of
cylinders with coil springs
within. The tops of the two
cylinders are joined by a pin,
and this joining pin is attached
to the lower leaf of the spring.
Inside the cylinders, pistons
are set above each spring, and

these are Connected, this COn- Fig. 425. J.H.S. Shock Absorber Has

1 . 1 m .1 Twin Springs Encased

nection being used for the

other half of the spring. At the bottom, the external bands on
each of the two cylinders are connected, so as to keep them parallel
at all times. Thus any movement upward of the lower part of the

213

Digitized by

Google

554 GASOLINE AUTOMOBILES

main-leaf spring tends to draw the enclosure for both shock-absorbing
springs upward. The springs themselves resist this and absorb
a large part of the movement both in force and distance.

Flat-Plate Recoil Springs. The third class, or flat-leaf spring,
is a semi-elliptic unit in miniature. It is placed upon the top of the
ordinary semi-elliptic spring, but it is reversed and has a spacing
plate between the two. The object of this plate is to prevent recoil
and to eliminate the rebound of the car body without restricting the
flexibility of the main springs. As shown in Fig. 426, the Ames
equalizing spring is constructed along these lines. As will be noted,
this allows all downward movement of the spring, having no influence
thereupon; but when the recoil, the upward equal and opposite
reaction, comes, the smaller upper spring opposes this reaction and

Fig. 426. Ames Equalizing Spring U a Simple Small Inverted Semi-Elliptic
Courtesy of Clarence N. Peacock and Company, New York City

minimizes it, so that little or none of it reaches the body or the
passengers.

Air Cushion. Perhaps the most complicated form of shock
absorber — certainly the most expensive and at the same time the
most efficient — is the air cushion. This form consists of a pair of tele-
scoping cylinders one being attached to the frame and the other to the
spring. When road obstructions cause the spring to rise, it pushes its
cylinder upward, bilt this movement is resisted by the air inside of the
cylinders. With the amount of air properly proportioned to the size
and weight of the car and its load, all this upward movement will be
absorbed and none will reach the body and its occupants.

This rough outline describes the Westinghouse air spring, shown
in cross-section in Fig. 427. In order to handle the air pressure and
keep the cylinders within the commercial limits, oil also is used in
the cylinders. This reduces the volume of contained air; but, for
each inch the device is compressed, the air is reduced by a greater
percentage of its original volume, consequently the resistance to
compression is greater than it would be without the oil.

214

Digitized by

Google

GASOLINE AUTOMOBILES

In the drawing, A is
the upper section of the
cushion chamber, telescop-
ing into the lower section
made up of tube B and
crosshead E. The outer
tube C is simply a guard.
A steel casting D is bored
out to form a guide for the
outer tube and crosshead,
and has a rectangular pad
F machined for bolting the
whole device to the bracket
attached to the frame of the
car. A shackle G is fastened
to the end of the car spring /
and is pivoted to the cross-
head E. Packing ring H is
used to make the inner cyl-
inder a tight fit in the outer
casing. A breather J is
placed on the side, through
which air is drawn by the
upward movement of tube
B through the medium of
the tightness of packing ring
H, just mentioned, and this
air, on the downward move-
ment, is forced through the
passage K to a port partly
surrounding the tube B.
There is no packing ring
between this tube and its
guide D, so the air blows
out and keeps the contact-
ing surfaces clean. A fur-
ther protection is afforded
by the felt-wiper ring L,

215

Digitized by

Google

556 GASOLINE AUTOMOBILES

which retains the grease in the groove just above it. is a rod con-
necting the two front or rear springs. At the top is the screw
cap M, covering the air valve N, which is designed to be used just
as the air valve in a tire.

The lower part of the device is filled with oil up to a level which
approximates the line Z, all above this level being air under pressure.
Consequently, the device actually compresses the air through the
medium of the oil, which is incompressible. This oil forms a seal for
the air chamber and prevents its leakage, although the oil itself is
allowed to leak through, this leakage being pumped back auto-
matically by the action of the springs. This works out as follows:

Fig. 428. Westinghouse Air Springs Applied to the Rear of Pierce Limousine

In what might be called the piston, although it is not, because it does
not move — the other parts moving relative to it — there is the plain
leather packing ring P and the cup leather R held out against the
sides of the cylinder by the conical ring and spring.

The small amount of oil which does leak past the packing rings
P and R is caught in the annular chamber S, whence it flows down
through the vertical (dotted) passage Q into the chamber just below
the ball valve T. In the center is a hollow plunger U of a single-
acting pump. This has two collars on its upper end V and W and
between them a disc X. This almost fills the passage just above it.
The plunger is held down by the light spiral spring shown pressing
on the collar V.

216

Digitized by

Google

GASOLINE AUTOMOBILES 557

When a road obstruction is met and the spring rises, crosshead
E rises and the upward movement of the oil takes the disc X upward
until it strikes and carries with it collar V; which lifts the plunger and
draws in a charge of oil. When the air compressed in the upper
chamber of the device expands, and the car spring / and crosshead
E go down again, the oil flows in the opposite direction, carries disc
X down against collar W, and forces the plunger downward. Then
the oil passes the ball check F, goes through the hollow plunger, and
is discharged back into the upper, or air, chamber. In the first place,
the oil is put in by taking off cap M and taking out the air valve N.
Then a special single-acting oil gun is used to force it in, a long nozzle
being necessary to reach down into the interior, with a stop to limit
this downward distance. The maker recommends that an excess be
put in and then slowly drawn off to the right level.

from* Cross Member

Fig. 420. Typical Semi-Elliptic Overload Spring

As will be seen from the foregoing, this device is essentially an
air spring, and the air cushion does the work; but it is the oil below
it, with its permissible leakage and with a pump to return this leaking
oil, which makes this device practicable. To show the exterior,
the part which most persons would see and remember, Fig. 428
is presented. This figure shows the rear end of a Pierce limousine
equipped with a pair of the Westinghouse air springs. Note the
breather, tie rod, cap at the top, cast guide at the bottom, and other
parts previously shown and described.

Hydraulic Suspensions. The majority of the hydraulic devices
developed as shock absorbers consist of turning vanes connected to
the axle or spring, enclosed in a liquid-tight case filled with some heavy
oil. There is a hole of small diameter in the case which connects the
two sides of the vane, its motion forcing the fluid through this hole.

217

Digitized by

Google

558 GASOLINE AUTOMOBILES

Thus the spring action simply pumps the oil from one side of the vane
to the other and back again, the resistance to the flow of the liquid
past the vanes and through the small hole absorbing all of the shocks.
Overload Springs. Overload springs are utilized with com-
mercial vehicles and may be of either the leaf or coil type, and so
arranged as to act only when the load on the main springs reaches a
certain weight. The wear plate may be a separate platform, as
shown in Fig. 429, or it may be formed integral with the pressure
block. Where coil springs are used, they are made of square section,
attached either to the frame cross-member or to the axle. Two such
springs are used, one on each side. The design in Fig. 429 is a semi-
elliptic. It is attached to a frame cross-member, and the ends are
free so that they may make connection with a separate spring seat
or a pad on the pressure block of the side spring when a predetermined
load has been applied. With some trucks the front springs are
mounted on a seat forged integral with the axle and are retained by
box clips; a coil spring is attached to the pressure block, which acts as a
bumper. Under excessive deflections these springs strike the bottom
flange of the frame and arrest the rebound motion of the vehicle
spring. The Jeffery Quad employs a spring bumper which is made
of flat metal and is termed a volute spring. It is attached to a bracket
fastened to the pressure block.

SUMMARY OF INSTRUCTIONS
STEERING

Q. Which wheel travels farther on curves and why?

A. The outer wheel must travel much farther on any curve, or
turn, because it is turning through an equal angle on a curve of much
longer radius. On very short turns, the distance the outer wheel
must travel can be more than 50 per cent greater, or longer, than that
of the inner.

Q. What general condition exists which makes the problem
of steering so complicated to lay out?

A. The answer to the previous question gives an idea of the
demands on the steering gear. The difference in the distances which
the two wheels must travel on all curves — some differences being as
high as 50 per cent, and with the difference shifting from one side to
the other — is the general difficulty.

Digitized by VjOOQlC

GASOLINE AUTOMOBILES 550

Q. How does the usual steering arrangement care for this?

A. By having the linkage which connects and steers the front
wheels arranged so that a prolongation of the center lines of the two
steering arms will pass through the center of the rear axle.

Q. How does this solve the difficulty?

A. When this arrangement is used, any swing or turn given to
the steering system, say a turn to the right, will swing the left-hand
knuckle through a larger angle than the right, although the two are
connected together by linkage. This means that the inner, or left,
wheel will swing about a shorter radius than the outer, or right, wheel,
since if the two were turned through equal angles, the two radii would
be equal.

Q. What other items complicate this steering problem?

A. . The fact that the wheels themselves must toe in slightly at
the front in order to steer easily and hold a straight line when set
straight. Furthermore, the wheels must be set with their tops wider
apart than their bottoms so that the line through the center of the
plane of the wheel strikes the cambered, or raised, road surface at a
right angle ; this makes the whole situation even worse.

Q. Is the ordinary front axle of such a design that it gives per-
fect steering?

A. No. But it represents a working approximation which could
not be improved upon without many needless complications. On a
sharp turn, probably one wheel is dragged around the curve for a
small portion of its length, but the distance is so small that it would
never be noticed by the eye nor discovered in any difference of life
in the tires.

Q. How is the turning of the steering knuckles about their
pivots obtained?

A. The swinging movement of the steering knuckles is obtained
through a fore-and-aft movement of the steering rod connected up to
one of the steering-knuckle arms by a ball joint.

Q. How is this longitudinal movement of the steering rod
obtained?

A. By a fore-and-aft swinging of the steering arm attached to
the steering gear.

Q. How is this fore-and-aft movement of the steering arm
produced?

219

Digitized by

Google

560 GASOLINE AUTOMOBILES

A. By the partial rotation of the gear within the steering gear
itself.

Q. And how is this partial rotation of the gear developed?

A. By the turning of the hand wheel, which turns the worm.
The hand wheel is fastened to the upper end of the steering post
proper (as distinguished by its stationary brass cover), while the
worm is fixed to the lower end of it. Consequently, whenever
the hand wheel is turned, the worm must turn also.

Q. Why are the worm and the gear used for steering gears?

A. The worm is used to secure irreversibility, as it is one of the
few forms of mechanism which will not transmit power back through
the entire group in the reverse direction, that is, it will not allow a
movement of the wheels to be transmitted back to the steering wheel
against the driver's w T ishes. In addition, it is compact, noiseless, easy
to care for, wears little, and is highly efficient.

Q. What other forms of mechanism are used for steering gears?

A. Bevel gear, screw-and-nut, double screw, worm gear and
full gear as distinguished from worm gear and partial gear, spur
gear, simple bent lever, and other forms.

Q. What are the disadvantages of these forms?

A. With the exception of the worm and full gear, all are wholly
or partially reversible, so if the front wheels strike an obstacle, the
shock is transmitted back to the driver's hands.

Q. How are steering wheels made?

A. In various ways. Some are rings of glued-up wood, to the
underside of which the arms of the steering-wheel spider are fastened.
Others have the arms cast integral with the aluminum rim; still others
are of bronze with a molded rubber surface applied to the bronze ring.

Q. Is the wood form, with spider fastened to it, popular?

A. It was, but it is rapidly going out in favor of something
better. This construction is now used only on the cheapest cars and
not on all of those.

Q. What are the advantages of the hinged, or folding, steering
wheel?

A. Folding up the wheel out of the way allows the driver to get
out on the lever side of the car, which might be practically impossible
otherwise. It allows stout drivers more comfort in getting in and out. It
is also an advantage when working in the front compartment of the car.

220

Digitized by LiOOQ IC

GASOLINE AUTOMOBILES 501

Q. What is the importance of the cross-rod at the front axle?

A. It is the only member tying the two steering knuckles
together. If this rod is bent, the wheels cannot be steered accurately ;
if it is broken, they cannot be steered at all. In fact, the car cannot
be moved forward when the rod is broken.

Q. Why is the rod usually placed behind the front axle?

A. As a protection against damage from high spots in the road.
If it is back of the axle, it is well protected ; but if the design places
the rod in front of the axle, it has no protection, and trouble is likely
to ensue on rough roads.

Q. Where is the front end of the steering rod carried?

A. As a similar means of protection, the steering rod is fre-
quently carried over or above the front axle, so that the axle will
protect it. Even when the design of axle, steering knuckle, and other
parts necessitates this rod being below, it is placed as close as possible
to the axle level, so as to get the maximum protection.

Q. What is the function of the steering knuckle?

A. It forms a pivot, or bearing, upon which the front wheel
rotates; but, in addition, it forms the basis of steering, being capable
of turning about a vertical (or nearly vertical) axis.
Questions for Home Study

1. Describe the complete steering mechanism of the Pierce-
Arrow car.

2. Why is it better to steer with the front wheels than with the
rear wheels?

3. Tell in detail how a worm and sector mechanism works.

4. Describe the working of a worm and nut device. Is it better
than a worm and gear and if so, why?

5. How is the Gemmer steering gear adjusted (a) for wear of
the worms; (b) for looseness of the steering wheel? How is it
lubricated?

6. Describe the Hindley worm. What are its advantages;
disadvantages?

7. Select and describe one form of steering-wheel construction.

8. How would you adjust a steering rod for (a) length; (b)
wear?

9. Tell the advantages and disadvantages of the various possible
positions for the cross-rod; for the steering rod.

221

Digitized by

Google

562 GASOLINE AUTOMOBILES

FRONT AXLES
Q. What are the usual front-axle classes?

A. Eliminating freak forms, axles are generally divided into
five classes: Elliott; inverted or reversed Elliott; Lemoine; front
drive; and fixed axle, or fifth wheel, form.

Q. What is the nature of the Elliott front axle?

A. The Elliott form has the end of the axle in the form of a jaw,
or Y, with a bearing above and one below the steering knuckle. The
latter fits in between the two parts of the jaw, or Y, and consequently
has a single central bearing.

Q. How does the inverted Elliott differ?

A. In the inverted, or reversed, Elliott form, the axle end is made
with a single central bearing, while the knuckle takes the form of a jaw,
or Y, and has the two bearings, one above and one below the axle end.

Q. Which of these two forms is the better?

A. There is little choice, but what there is seems to favor the
Elliott form because it gives a stiffer and better bearing in the axle end,
which is generally a good size rigid member. In fact, the axle ends
can be made large enough in this form to have ball, roller, or other
anti-friction bearings. This is not true with the reversed form.

Q. How is the Lemoine axle constructed?

A. The steering knuckle and its pivot are, integral and form a
letter L. The axle end is plain and forms a single bearing on the upper
end of the steering pivot. In the regular Lemoine form, the L has
its vertical leg extending upwards, and the axle is on top of the knuckle,
so to speak. As constructed in United States the vertical leg of the L
is turned downward, so that the axle is below the knuckle

Q. What are the advantages of this form of construction?
$ A. Both axle end and knuckle are simplified and can be con-
structed more cheaply. Moreover, the complete axle can be assembled
or disassembled more readily and quickly. Some consider that this type
has a nicer, cleaner appearance and thus improves the front of the car.

Q. What is the disadvantage of the Lemoine type?

A. The principal disadvantage of the Lemoine axle, ascom pared
with other forms, is the difficulty of suitably handling the bearing
loads. The ordinary axle has separate radial-load bearings and
thrust washers or thrust bearings. In the Lemoine the axle-end bear-
ing must handle both radial and thrust loads, as well as road shocks*

Digitized by

Google

GASOLINE AUTOMOBILES 563

Q. What are the usual axle materials?

A. Modern practice restricts front axles to hand- and drop-
forged steel, to tubular centers with forged ends, and to pressed steel.
The latter is little used, however. Cast steel and manganese bronze
as well as wood, have been used.

Q. What are the usual axle bearings?

A. Ball, roller, and plain bearings are widely used. For the
sake of simplicity and compactness, the steering-pivot bearings are
often plain, while the wheel bearings' on the knuckle end are about
evenly divided between ball and roller. Thrust bearings are about
evenly divided between plain steel bearings with bronze washers, on
the one hand, and with ball bearings, on the other.
Questions for Home Study

1 . Describe a good method of truing front wheels.

2. How would you determine that front wheels were out of
alignment?

3. Describe in detail the (a) Overland front-axle; (b) the
Christie; (c) the Marmon.

4. How are axles lubricated, with reference to (a) wheel bear-
ings; (b) steering pivots; (c) thrust washers or thrust bearings?

5. What are the disadvantages of cast front axles?

6. Are ball bearings better than roller bearings for front-axle
pivots and if so, why?

7. Describe in detail the process of straightening a bent front
axle. Would you use a template and if so, why?

FRAMES

Q. What is the need for a frame in an automobile?

A. Every automobile needs a frame, stiff and strong enough to
support all the units for power development and use, down to the
springs.

Q. Is there any radical difference between pleasure-car and
motor-truck frames?

A. None, except that the truck frame must carry a much heav-
ier load and, therefore, needs to be stiffer and stronger and that it
must cost less relatively, thus necessitating a form or shape which is
cheaper to construct.

Q. What materials are used for frames?

223

Digitized by

Google

564 GASOLINE AUTOMOBILES

A. Principally steel and wood. Steel is divided into rolled,
used mainly for trucks; and pressed, used for pleasure cars and for
the smaller trucks, or delivery wagons. Wood is divided into plain
straight wood, laminated wood, and wood used as a filler for steel.

Q. Is wood used at all widely?

A. No. With the exception of Franklin, using laminated wood ,
and of a few light cars and light trucks which have a wood filler inside
of a pressed-steel frame, wood is used very little.

Q. Is steel tubing used for frames?

A. Frames are no longer constructed entirely of tubing, although
this has been tried, but some designers use tubular cross-members
for the support of the engine, the transmission, and other units.

Q. Is structural steel widely used?

A. For pleasure cars very little, if at all; for trucks quite freely,
but in gradually decreasing quantity. Frame makers are producing
better and cheaper frames of pressed steel each year, gradually elimi-
nating any and all arguments in favor of rolled or structural steel.

Q. What is a frame "kick-up"?

A. When the rear end of a frame otherwise fairly straight and
level is bent sharply upwards from two or three to as much as ten
inches, beginning just forward of the rear axle and carried out to the
rear end of the frame on this higher level, this whole raised rear end is
called a kick-up.

Q. What is the purpose of a kick-up?

A. It lowers the central part of the chassis relatively, thus giving
a lower step, incidentally lowering the center of gravity and making
the car safer. It raises the rear end to give adequate rear springing.

Q. What is the shape of the modern frame, in plan?

A. It is gradually assuming a considerable taper. Originally,
the frame formed a rectangle, with straight side members. Then it
was found advantageous to narrow the front end to give more room
for the front wheels to turn and thus allow a shorter turning radius.
As this had the additional effect of shortening the engine-supporting
arms, the makers were able to eliminate the sub-frame, with a saving
of expense and weight. Finally, the width needed for modern
touring car rear seats gradually widened out the rear ends of the
frame, while the narrowing at the front became so great as to put a
weak spot in the frame where its greater load had to be carried. It

224

Digitized by CjOOQIC

GASOLINE AUTOMOBILES 565

then became a logical step to make the frame taper from front to rear
continuously, with straight sides. This is the form which all frames
are assuming now.

Q. In what other ways do modern frames differ?

A. The rear cross-member is being eliminated very widely, as
is also the front cross-member, so the triangular-shaped frame is not
closed at either end. Formerly, the depth of the frame w*as pretty
much the same from front to rear, but now this tapers very materially
from the front up to the middle and then down again at the rear. A
good stiff typical frame would be perhaps 2\ inches to 3 inches deep
at the front, 6 inches deep in the middle, and perhaps 2\ inches to 2J
inches deep at the rear. In short, except for perhaps 20 to 24 inches of
length right in the middle, the frame depth would differ continuously.

Q. What is the advantage of varying the depth so much?

A. It eliminates every pound of excess weight, putting much
metal where there is heavy load and severe stresses and little metal
where the load and the stresses are light.

Q. Is this form of construction more expensive?

A. No. The art of pressing the frame out of sheet steel has been
developed through large quantity production to such an extent that a
frame of this type, with a constantly varying depth, costs no more than
a straight frame cost four years ago.

Q. Does this form give the repair man more to do?

A. No. On the contrary, frames give less trouble in the way of
sagging, breaking, or cracking than ever before. The frame troubles
of today are mainly due to poor or light design, in an effort to lower
weight too far, or to accidents.

Q. What has been the effect of cantilever springs on frames?

A. One effect of cantilever springs for rear use has been to
eliminate the rear cross-member, as spoken of previously. Another
effect has been to continue the deepest section back quite a few inches
to the point of support of the front end of the cantilever.

Q. Is the trussed, or latticed, frame widely used?

A. No. Only by one or two makers, although a few heavy cars
have a truss rod below the main frame to add stiffness and strength.
The trussed, or latticed, frame is a new departure in frame design.

Q. What are the noticeable tendencies in frame construction,
other than those already mentioned?

225

Digitized by

Google

566 GASOLINE AUTOMOBILES

A. The use of heavier frames, that is, heavier sections of metal,
deeper side members, and general stiffening is being accomplished
without much gain in weight, owing to the better distribution of the
metal. The combination of other units, as steps, step supports, and
fenders with the frame is being worked out, this being one of the tend-
encies in construction. The general carrying of spare tires at the
rear is having an influence, but there seems quite a tendency to con-
struct the body so as to enclose the tires, which, if carried out, would
change this.
Questions for Home Study

1. How would you repair a sagged frame, if sagged at (a) front
end; (b) center; (c) rear end; (d) cross-member?

2. Describe the method of welding a cracked frame by the
oxy-acetylene process.

3. Describe the following frames ir detail (a) Steams-Knight;
(b) Marmon; (c) Fergus.

4. How is the Franklin wood frame built up?

5. How is what is called an "armored frame" made?

6. Tell how to remove and replace an underpan.

7. What material is usually used (a) for a truck frame; (b) for a
light pleasure car; (c) for a heavy touring car?

8. Give the advantages and disadvantages of pressed steel for

frames.

SPRINQS AND SHOCK ABSORBERS

Q. What is the need for vehicle springs?

A. To support the load in a flexible manner so that the jolts and
jars of the road will not be transmitted to the passengers or load. In
addition, a flexible connection between the power plant and the road
wheels is needed.

Q. How many recognized different types of spring are in use?

A. Seven; all of which are made and used in all sizes and qual-
ities for all kinds of load.

Q. What are these seven types?

A. The semi-elliptic, the full elliptic, the three-quarter elliptic,
the platform, the cantilever, the quarter elliptic (or half semtelliptic,
as it is sometimes called), and the coil. All but the last three also are
made with scroll ends, w r hich alters the general appearance without
altering the type of action.

226

Digitized by

Google

GASOLINE AUTOMOBILES f>f>7

Q. What is the shape of the semi-elliptic?

A. This form has a slight bow upwards, the two ends being
slightly higher than the middle. The middle is attached to the axle
and the ends to the frame, and when load is applied, these ends come
down, flattening the spring so that it approaches a straight line.

Q. Describe the full-elliptic spring.

A. This form has the shape of two semi-elliptics, one inverted
and set on top of the other. This gives it the appearance of an elon-
gated letter O with points at the ends. The lower half is attached to
the axle and the upper half to the frame, and loading tends to bring
the two halves closer together, flattening the O still farther.

Q. What is the form of the three-quarter elliptic spring?

A. This consists of a flat lower semi-elliptic member and a
highly curved quarter-elliptic upper member, the two being joined
by means of a shackle. With the exception of the difference in
curvature of the two parts and the use of the shackle to join them,
this has the appearance of a full elliptic with the upper forward
quarter cut away. When loaded, both members give slightly, the
upper quarter more than the lower half. • The shackle gives a consid-
erable difference in this action from that of the full-elliptic.

Q. What is the platform spring like?

A. This spring consists of three semi-elliptics joined together at
the ends so as to form three sides of a rectangle. The two sides are
fastened, respectively, to the axle at the middle of each, to the frame
at their front ends, and to the third spring at the rear ends. The rear
spring is inverted and its center is fastened to the center of the rear
end of the frame, while its ends are shackled to the rear ends of the two
side springs. This makes a combination in which the normal semi-
elliptic spring action is modified somewhat by the inversion of the rear
cross-member and by the use of shackles at the ends of all three.
While popular three or four years ago, it is now going out in favor of
the three-quarter elliptic.

Q. What is the cantilever spring like?

A. It consists of an inverted semi-elliptic fixed or shackled to the
outside of the frame at the front end, hinged or pivoted slightly
forward of its center to the outside of the frame, and having its rear
end attached to the upper or lower surface of the rear axle. It is used
in greater lengths than any other form of spring and is very popular.

227

Digitized by

Google

568 GASOLINE AUTOMOBILES

It is the most simple spring now in use and is said to give the easier
riding of all.

Q. What is the quarter-elliptic spring like?

A. This is simply what its name indicates, one-half of a semi-
elliptic or one-quarter of a full-elliptic. Its front end is fixed to the
frame outside, and the rear end is shackled or allowed to slide on the
rear axle. It is generally inverted. In reality, it is a cheap substi-
tute for the cantilever or inverted semi-elliptic, this use being allow-
able because of the light weight of both car and load.

Q. Is this used in any different way?

A. Sometimes a pair of these is used, one above the other, with
the idea of doubling the resistance or rather of giving equal resilience
with but half the movement.

Q. What is meant by underslinging?

A. When this refers to frame, the entire frame is placed below
the springs. This has gone out of use. When referring to springs,
this means placing the spring below its support, as below the rear axle.
This construction lowers the frame and center of gravity by the
thickness of the spring plus its seat plus the diameter of the rear axle,
sometimes amounting to a total of five inches. It is growing rapidly
in popularity.

Q. What is the purpose of a shock absorber?

A. To absorb the small vibrations while the spring cares for the
large ones. It generally takes the form of any auxiliary spring or
friction device.

Q. What are the general classes of shock absorber?

A. Coil spring, flat-plate spring, friction plates, compressed air,
and a few hydraulic (or liquid) forms.
Questions for Home Study

1. How are springs lubricated (a) as to leaves; (b) as to shackles?

2. How are the spring leaves separated for lubrication?

3. Describe a method of getting home with a broken rear spring.

4. Why do racing cars have their springs w r ound with rope or
cloth?

5. Describe the following car springs in detail: King; Winton;
Ford.

6. How do electric car springs differ from those of gasoline cars?

7. What are the standard spring-plate widths?

228

Digitized by

Google

Digitized by

Google

Digitized by

Google

GASOLINE AUTOMOBILES

PART VI

FINAL-DRIVE GROUP

REAR AXLES
TRANSMISSION

Units in the Final Drive. Generally speaking, the transmission
is located in the middle or forward end of the chassis. When this is
the case, the final drive begins right at the rear end of the transmission.
The units back of the transmission, then, would be a universal joint;
a driving shaft; possibly another universal joint; the final gear
reduction; rear-axle shafts and enclosure; the differential; the torque
rod, or tube, or substitute for it; the wheels; the brakes; the tires;
and other smaller units.

Even when the transmission is placed on the rear axle, this
general layout is changed little, and the transmission, which has been
covered in detail previously, is not considered again. In the case of a
chain drive, which is still used on one pleasure car or perhaps two, on
a number of small trucks, and on a large number of large trucks, this
layout is changed considerably. In the large trucks, the transmission
in perhaps 90 per cent of all cases would be in a unit with the jack-
shaft, which means that for consideration in the final-drive group
there would be only the driving shaft to the transmission; the joint
or joints in it, if any; the chains and the method of adjusting them;
the rear axle and wheels; the brakes; the differential, of necessity
becoming a part of the transmission; and the jackshafts.

To make this clear and point out the various units, it will be
noted in Fig. 430 that it is a unit power plant. Directly back of the
transmission is the first universal joint, driving through the hollow
propeller shaft to the rear axle, in front of which is the second universal
joint. The rear-axle group includes the axle shafts, differential gears,
final gear reduction, gear housing, and the wheels. The torque
reaction of the drive, to be explained later, is taken by the torque rod,
marked in the drawing, which connects the rear axle to the under

231

Digitized by

Google

570

GASOLINE AUTOMOBILES

side of the stout
frame cross-member
in front of the axle.
Universal Joints.
The purpose of taking
upthe universal joints
— it can be seen from
the drawing — is to
show how the rear
axle rises and falls or
moves sidewise in
either direction with-
out making any dif-
ference in the trans-
1 mission of power to
g J the axle. When joints
§3; are used at other
fe - points, the purpose is
| | generally to take care
^ ? of any lack of align-
3 1 ment, but here the
purpose is to transmit
power at an angle.
The transmission
fe | of power at an angle is
effected by construct-
ing the joint so that it
can work at any angle.
Usually, this is done
by constructing the
central member in the
shape of a cross, with
four projecting arms
or pins, all in the same
plane. The ends of the
two shafts are made in
the form of forks, or
Y's, and are set at

232

Digitized by

Google

GASOLINE AUTOMOBILES 571

right angles to each other, that is, the forks are laid in planes which
are at right angles. The fork on one shaft is fastened to a pair of
diametrically opposite pins, while the fork on the other shaft is fas-
tened to the other pair of diametrically opposite pins. Each shaft is
able to turn on its pins about a line through the center of both. As
these two lines are in planes which are at right angles to one another,
but intersect at a common center, movement is possible in either
plane, or by combination movements of both, in any direction.

Slip Joints. In many situations, a real universal joint is not
needed, since the parts are not actually free to move in all directions;
but what is needed is slight freedom up and down or sidewise
combined with possible fore-and-aft movement. In such cases a slip
is used, the name giving the idea of a joint which allows one shaft to
slip, or slide, inside the other. The general construction of slip joints
varies. Sometimes a round gear is fastened to the end of one shaft;
this gear has a fairly large diameter and many teeth, with the teeth
chamfered to an unusual extent — almost rounded, in fact. An internal
gear of the same size and number of teeth with similarly rounded
profiles is meshed with the hollow gear of the other shaft. Both
gears have unusually wide faces. This combination gives an action that
is almost universal, and also allows lateral sliding of perhaps \ inch.

The second form of slip joint consists of a squared shaft and
square enclosure. The end of the shaft has a member split along a
central line attached to it; the exterior approximates a round of large
diameter, but the interior is machined to a perfect square, one-half
in each part of the split member. Attached to the end of the other
shaft is a member machined to an exact square, but slightly rounded
in a fore-and-aft direction. The square will drive, no matter in what
part of the housing it is located, so that considerable fore-and-aft
sliding is possible. In addition, the rounded surface of the square
gives an approximate universal effect. The split housing is used to
make assembling and disassembling easier and much quicker. Some-
times such a housing is put on the end of each shaft, the connecting
member being made in the form of a dumb bell, but with two square
ends — one to work in each squared-out housing. In this way the
effect of a full universal joint with the fore-and-aft sliding is obtained
at less cost, and with easier assembling and disassembling as extra
advantages.

233

Digitized by

Google

572

GASOLINE AUTOMOBILES

Occasionally a square joint is constructed as simple and small as
possible, in which case the housing is not split and the shaft end is not
rounded. This gives a simple square which drives through a simple
squared-out hole. In this case there is no universal action, but simply
lateral or sliding freedom.

Other Flexible Joints. To get away from the complication of the
universal joint and yet give practically the same results, many other
forms have been produced. A very thin disc of tempered steel, with
the two shafts bolted to the two opposite sides of it, has been used.
The metal will bend and give enough to allow considerable angle of

drive. Later forms of the same
joint use leather in several
thicknesses, the leather being
bolted up to the two shafts in
the same way. A joint of this
kind, consisting of several lay-
ers of fabric which have been
fastened together in lamina-
tions until a disc of fair thick-
ness, say \ to f inch, has been
built up, is shown in Fig. 431 .
Then the leather is cut round
and drilled for the bolts. In
this form, six bolts is the pre-
ferred number, three for each
shaft end ; they are in a three-
armed spider fastened to the
end of each shaft, as the figure shows. These newer forms are usually
convenient for the repair man, for they allow breaking into the main
shaft by the simple removal of the three bolts (or two as the case may-
be). By taking out the bolts at each end of such a shaft, the shaft
itself can be removed, leaving the other units in the chassis ready for
immediate removal, according to the needs of the repair job.

Types. Possible types of final drive, from the gear box to the
rear axle and the driving wheels or from the motor to the gear box —
in case this is mounted on the rear axle, as is not uncommon practice —
are practically limited, in cars of sound design, to shaft and double-
chain constructions.

Fig. 431. Laminated Discs Forming Flexible
Shaft Coupling
Courtesy of Thermoid Rubber Company,
Trenton, New Jersey

234

Digitized by

Google

GASOLINE AUTOMOBILES 573

Shaft Drive. In its usual form, shaft driving in an automobile
involves simply a propeller shaft interposed between the rear v axle
and a revolving shaft in the car above the spring action. There is
some provision for taking the torque of the shaft and of. the axle so
that they shall maintain their proper relative positions.

In Fig. 432, a typical short driving shaft with its two universal
joints is shown. This is such a shaft as would be used in the car
shown in Fig. 430, except that the latter is a long wheel-base car with
its transmission in a unit with the motor and clutch and thus, far
forward. This combination necessitates a very long propeller shaft.
The one shown is actually from a car having a short wheel base, with
the transmission located amidships. This is a combination which
calls for a fairly short propeller shaft.

The short shaft, shown in the figure, is a solid shaft. The modern
tendency toward lighter weights is being worked out in the case of

Fig. 432. Ordinary Driving Shaft of Solid Form with Two Universal Joints

propeller shafts, and many are now made hollow. By making the
diameter slightly larger and having a large central hole, unusually
light weight is obtained with all the strength of the solid form. In
addition, the larger diameter hollow shaft has more rigidity than the
small diameter solid form, and in many of the modern cars without
torque or radius rods, unusual rigidity of the driving shaft is necessary.
Other forms have been used for the driving shaft, but they come more
or less in the freak class. About two years ago, a car was brought out
with a spring, or flexible, shaft, which consisted of a rectangular
member of considerable height, but fairly thin. The idea was not only
to transmit the power of the engine, but to do it in a flexible manner,
that is, the shaft was supposed to absorb all the sudden changes,
such as quick acceleration or quick braking. At the same time, one of
the electric-car makers brought out a chassis with a square driving
shaft of very small size. This served the same purpose as the flexible

235

Digitized by

Google

574 GASOLINE AUTOMOBILES

shaft only in a different way; its two ends, setting in square holes,
formed two sliding joints without further machining.

Fig. 433. Ford Final Drive, Differential, and Axles

Fig 434. Worm and (Jear for Rear Axle, Showing Upper Position of Worm
Courtesy of Timken-Detrott Axle Company, Detroit, Michigan

An objection to the shaft type of drive is that the reaction of the
revolving shaft tends to tilt the whole car on its springs in a diree-

236

Digitized by

Google

GASOLINE AUTOMOBILES

575

tion opposite to that in which the shaft is turning. In some cars,
this is counteracted by the use of slightly heavier springs on one
side. The advantages of the shaft drive are the complete enclosure
of all working elements, with their consequent protection from dirt
and the assurance of their proper lubrication.

The final drive of the Ford automobile, in which the end of the
propeller shaft is shown at A, together with the bearings in which it
revolves, the pinion by which it drives the car, the axle, the differen- .
tial, and the bearings of
the floating inner ele-
ments of the axle is illus-
trated in Fig. 433.

The shaft drive does
not necessarily include
the use of bevel gears for
the final reduction at the
rear axle; in fact, almost
any form of gears may
be used. In one well-
known shaft-driven com-
mercial car, the final
gears consist of a pair
of plain spur gears, while
on the shaft of the second
of these gears is a pair of
bevels.

As soon as the bevel
gear final reduction dis-
closed its limitations and
disadvantages, designers started to displace it. One of the earliest
forms of gear used for this purpose was the worm, an example of which
can be s£en in Fig. 434. This figure shows the worm placed above the
wheel, but the lower position, which is also used, has the advantage of
copious lubrication. In the form shown, the wheel must come directly
beneath the worm so that the differential may be set inside of it.

The worm is usually more suitable for slower moving vehicles
which have a large reduction of speed between engine and rear wheels,
that is to say, it is peculiarly fitted to electrics and motor trucks of all

Fig. 435. Spiral Bevel Gears — a New Noiseless Type

for Rear Axles

Courtesy of Timken-Detroit Azle Company,

Detroit, Michigan

237

Digitized by

Google

576 GASOLINE AUTOMOBILES

sizes, on which it is finding wider and wider use. On pleasure cars
of the average size and type where a speed as high as 50 m.p.h. or
higher is expected by all concerned, it has not been found suitable and
consequently is not being used.

A later form, which is designed to replace the straight bevel, is
the spiral bevel. % This is primarily a bevel gear with spiral teeth, the

Fig. 430. Typical Roller Chain

idea being to incorporate in the bevel gear the advantages of the
spirally shaped worm tooth, without its disadvantages. As Fig. 435
shows, this makes a very compact and neat arrangement, the differ-
ential fitting within the larger gear in the same manner as with the
worm.

Double-Chain Drive' Tl\e use of double chains, by which the
driving wheels of an automobile are driven from a countershaft
across the frame of the machine, is a practice possessing a number
of advantages. But because of the noise and quick wear with badly

Fig. 437. Typical Silent Chain

designed chain drives and the difficulties of completely enclosing the
driving mechanism, chains are not now as popular as formerly.
Nevertheless, the elimination of universal joints working through
large angles and under heavy loads, the avoidance of heavy weights
carried on rear axles without spring support, the lowering of the
clearance by the differential housings, etc., are very real objections
that the double chain avoids.

For trucking and other heavy service, chains are still commonly
in use, and it is the belief of many that a better understanding of their

Digitized by CjOOQ IC

GASOLINE AUTOMOBILES 577

merits and the means of securing these merits in positive and per-
manent form will result in their more general use.

A typical roller chain of the type most used for automobile
drives is illustrated in Fig. 436.

- Silent chains, of the types illustrated in Figs. 437 and 438, possess
certain points of superiority over roller chains and are therefore com-
ing increasingly into use for camshaft drives, in gear boxes, etc., and
there is some possibility that they will find more extensive application
to final drives than at present.

The action of a silent chain is illustrated in Fig. 438, in which it
is seen that as the chain links enter the sprocket teeth the chain
teeth at the same time close together and settle in the sprocket with

5TH. PQS/770M

TH. POJ/T/OW

3RD. POS/T/OM

zm pos/t/o/v
jsr. posmon

Fig. 438. Action of Silent Chain and Sprockets

a wedging action that causes them to be absolutely tight, but without
any more binding than there is backlash.

To keep silent chains from coming off sidewise from the sprockets
over which they run, it is. customary to make the side links of deeper
section than the center links, as is illustrated in Fig. 437. Another
successful scheme is grooving the sprocket to receive a row of special
center links in the chain, which are made deeper than the standard
links.

At present, only one American pleasure car, the Metz, has
final drive by means of silent chains. This is a small car with a
friction transmission, the drive from the ends of the cross-shaft being
by enclosed silent chain to each rear wheel.

Torque Bar and Its Function. It is a well-known fact that action
and reaction are equal and opposite in direction, so that if a gear is
turned forcibly in one direction, say clockwise, there is a reaction in
the opposite direction, or counter-clockwise. This is the simple basic
reason for a torque bar, or torque rod, on an automobile. It is needed
with any form of final drive, but it takes different forms, according to

239

Digitized by

Google

578 GASOLINE AUTOMOBILES

the type of gear used. The bevel and spiral bevel used on 88 per cent
of the 1917 cars are explained in detail as follows: Fig. 439 shows the
rear end of a typical pleasure-car chassis. The engine is rotating
clockwise, and so is the driving shaft A, as shown by the arrow. The
shaft turns the pinion B in a clockwise direction, which rotates
the large bevel C so that its top turns toward the front of the car.
The bevel C turns the rear axle D and the rear wheels (not shown)
in the same direction; so the car moves forward.

In addition to the gear C and shaft D turning easily in the axle
housing E, there is an equal and opposite reaction which tends to keep
them stationary, while the bevel pinion B and driving shaft A tend
to rotate around the rear axle as a center in a counter-clockwise direc-

Fig. 439. Diagram to Show What Torque Is and Why Torque Rods are Necessary

tion, as shown by the diagram. If the rear axle were held firmly
so it could not rotate, and there was nothing to restrain the bevel
pinion and shaft, this could easily happen. However, since we do
not wish this to happen, a means is provided to oppose this action
and prevent it from happening. Since the turning force which makes
the shaft rotate is called the torque, this rod, bar, or tube, whatever
its form, is called the torque member.

In the sketch, the torque member is marked F and is attached to
the frame cross-member G, between a pair of springs, so as to cushion
the shocks of sudden car or shaft movements. The force on this is
the force which tends to rotate the driving shaft and pinion counter-
clockwise, so that it works upward, as shown by the arrow. The
frame prevents this and absorbs the force.

Digitized by VjOOQIC

GASOLINE AUTOMOBILES

579

Driving Reaction. As has been stated, the power, or torque, of
the motor is used to rotate the rear wheels. These stick to the pave-
ment or road surface, so
the car is really pushed
forward. Since it is this
pushing action which
really moves the car for-
ward, it is very interest-
ing to note how this push
is transmitted from the
wheels and rear axle to
which they are attached
to the frame which car-
ries the body and pas-
senger load.

The transmission of
the drive to the body is
accomplished in one of

Fig. 440. Diagram to Explain Driving Reactions

Usi ~

sing Radius Rods

three ways. The first form was the so-called radius, or distance,
rod, which the shaft-driven car inherited from the chain-driven form.
In the chain drive, these
rods were a necessity and
served a double purpose;
they kept the driving and
driven sprockets the
proper "distance" apart
for correct chain driving
(hence their name "dis-
tance" rods), and they
also transmitted the drive
back to the frame. On
the shaft-driven car, the
distance function is not
needed, so they are called
radius rods. As shown
in Fig. 440, they transmit
the drive forward to the frame, thus propelling the car in the direc-
tion of the arrow,and they also keep the rear axle in its correct position.

Fig. 441. Layout of Driving Reaction Using Torque
Tube around Shaft

241

Digitized by

Google

580

GASOLINE AUTOMOBILES

In lightening and simplifying the shaft-driven car, designers
figured that three members for the torque and driving reactions were
too many; so a design was worked out in which all three were combined
into one, which is a form of tube surrounding the shaft. This made
the member light but strong, and simplified the whole rear end. As
shown in Fig. 441, the tube has forked ends at the front, which are
connected to the frame cross-member in such a way as to absorb the
torque reaction and also to transmit the drive. The method has
the further advantage of needing but one universal joint, and that
at the front end. Furthermore, it gives a correct radius of rise and
fall for the rear axle, since the center of the combined torque and drive

member is also the centerof
the universal joint in the
driving shaft. In the form
shown in Fig. 339 (radius
rods not shown), the two
different centers will be
noted, the torque rod giv-
ing a greater radius than
the shaft. Similarly, in
Fig. 440 (where the torque
rod is omitted for clear-
ness), the rods give a
longer radius of rear-axle
movement than the shaft,
which has a joint close to
the axle.

It will be noted that both these methods allow complete freedom
of the rear springs, which may be of any form, and shackled at the
front end if desired by the designer. In its newest and simplest form,
the so-called Hotchkiss, or spring, drive has both the radius and
torque rods omitted, the springs being forced to transmit both forces,
as shown in Fig 442. In this case, the forward end of the rear spring
must act as a rod, or lever, instead of as a spring, and must be fairly
straight and stiff without a shackle, but firmly pivoted on the frame.
In addition, the shaft must have two universal joints, as shown.
It must be stated, as a simple fact, that this last form is increas-
ing rapidly and at the expense of the other two. On smaller lighter

Fig. 442. Arrangement of Driving Reaction When
Hotchkiss Drive is Used

242

Digitized by

Google

GASOLINE AUTOMOBILES 581

cars it is gradually replacing all other forms. It has the advantages
of minimum weight and fewer parts, and applies the driving force in a
direct line to the frame, the same as the two radius rods do. On the
other hand, it makes the springs serve a triple purpose, the demands
on these for torque and drive transmission and absorption being such
that the spring flexibility must be negligible, which makes the car ride
hard. In addition, making the springs handle the three widely
different actions puts additional stresses upon them, so that they are
more likely to break. On the medium size and larger heavier cars,
this construction is not gaining so rapidly.

TYPES OF REAR AXLES

Classification. Rear axles may be divided into the following
classes, distinguished according to the method of carrying the load and
taking the drive: the form in which the axle carries both load
and drive; the semi-floating form, carrying the drive and a small part
of the load, the axle shafts not being removable without removing
the wheels; three-quarter floating form, carrying the drive and a small
part of the load, the latter being divided between the shaft and its
housing, but with the shafts removable; seven-eighths floating form,
carrying the drive but not the load, the arrangement of bearings to
take the load being such that the wheel hubs do not rest wholly and
solely upon the axle-casing end; the full floating form, in which the
shaft does nothing but drive, and is removable at will without dis-
turbing the wheel and wheel weight resting on the axle-casing end,
which is prolonged for this purpose.

The seven-eighths floating type has been developed to meet the
need which arose for a floating construction, in which the axle casing
did not pass entirely through the wheel hubs. With the full floating
form, any accident to the wheel, in which it was struck from the side,
also damaged the casing, or tube, end. The result of this in nine
cases out of ten was to make the removal of the wheel impossible,
because the tube end, which projected through, was bent over.
Moreover, repairing in such a situation called for a new axle casing
— a very expensive proposition. Consequently, the seven-eighths
floating form was developed to present all the advantages of the
full floating form, with this serious drawback eliminated by a rear-
rangement of the parts which did not necessitate prolonging the axle

243

Digitized by

Google

582

GASOLINE AUTOMOBILES

through the wheel hubs. Despite the facts, it did not gain as rapidly
as the other floating forms, and now is almost out of use.

The three diagrams in Fig. 443 explain the types as well as words
can. At the top is shown the full floatingaxle, the best but most expen-
sive form. In the middle, the semi-floating axle, which makes the axle
shaft do all the work — carrying load as well as transmitting power — is

shown. At the bottom is the
three-quarter floating form,
which is really a combination
of the other two forms and
possesses a maximum of ad-
vantages with a minimum
cost. The car weight is car-
ried on the tubing, while the
shaft drives and carries a por-
tion of the side stresses to
which the wheels are sub-
jected, the quantity depend-
ing upon the construction of
the bearings.

Of the 1917 cars, prac-
tically 30 per cent (29.5) have
the three-quarter floating rear
axle, 25.5 per cent the semi-
floating form, and 43.5 per cent
the full floating form. In 1916,
however, the three-quarter
form was used in but 22.8 per

Fig. 443. Arrangement of Axle Bearings and Hous- Cdlt, and in 1915 in Only 18.5
ing in Three Principal Forms of Rear Axle ^ ^ q{ ^ ^ ^^

figures show how the three-quarter floating axle has been gaining
constantly at the expense mostly of the floating form, the semi-floating
form practically standing still for three years.

Axle Carrying Load and Drive. The type in which the axle
carried both load and drive was a peculiar one and did not last long.
In this form, the rear-axle shafts were exposed and carried the
weight of the load at the spring sea'.?, which were bushed to allow
the shafts to turn within them. Thi>> made a place which was hard

214

Digitized by

Google

GASOLINE AUTOMOBILES

583

to lubricate, and yet which was down in the dust and dirt, so that
lubrication was a great necessity. All these causes, coupled with the
fact that the axle carried both load and drive, caused its disuse.

Dropped Rear Axle of Full Floating Type. The dropped type
of axle is not much used at present for cars of the shaft-driven type,
the dropped part of the axle bed being used to hold the rearward-

pl».ppf1 transmission. Fie 444 shows a fnrmpr A inert ran tvn#». itj

Fig. 444. Rear Construction Embodying Dropped Type of Hear Axle

which the weight of the car as well as the weight of the load is carried
on the I-section drop-forged rear axle, while the drive is transmitted
from the transmission by the usual shafts, which carry no load. The
cut shows the complete assembly above and the dropped axle below.
The round ends of the I-beam axle are hollow, carrying the driving
shaft through the central hole and the wheels on bearings which
fit over the outside. The wheels will revolve on the bearings, even
if the inner shafts and transmission be removed from the chassis.
Despite its manifold advantages, the expense of constructing
an axle of this type — it is practically the same as that of two ordi-

245

Digitized by

Google

584 GASOLINE AUTOMOBILES

nary axles, making the total cost double that of any other form — has
worked to prevent its general use. In fact, it is not now in use in
this country, as the maker has gone out of business.

A prominent French constructor, De Dion, utilizes a dropped
rear axle, but, in this, the differential casing and gearing are suspended
from the frame and drive down to the axle shaft by means of a pair
of short inclined shafts with two universal joints in each, that is,
the drive from the differential to the two wheels contains four universal
joints. The inevitable loss due to the necessarily short inclined shafts
and to the two joints in each has deterred other manufacturers from

Fig. 445. Typical Ball-Bearing Differential

using this form, although a few makers — notably the Peerless Com-
pany — have inserted a pair of joints in the rear axle in order to give the
rear wheels the same camber as the front wheels. As this necessitates
inclined shafts, the joints are needed to connect the horizontal center
part with the inclined ends.

Clutch Forms in Semi-, Three-Quarter, and Full Floating Types.
The main point of difference in the various semi-, three-quarter, and
full floating axles, aside from the principle of design w r hich makes them
decidedly different, is the clutch, by means of which the wheel is driven.
In some cases, this clutch takes the form of a gear, with straight sides

246

Digitized by

Google

GASOLINE AUTOMOBILES 585

and external notches, or jaws, to correspond with the teeth, but
usually it is more of a claw type, the driving ends projecting inward
from the point of attachment to the axle shaft. Another notable
point of difference — and one which makes a huge difference in the cost
— lies in the machining of these jaws, whether they are attached to the
axle or machined up with it in one piece. The latter is considered
better and stronger in every way, but, as it is much more expensive,
it is used only on the best cars.

The. driving clutch takes various forms, one of which is shown
in the Studebaker axle, Fig. 445. In this type, the axle is a square
rod acting within a square hole in the hubs. In the small detail at
the upper left-hand corner the letter A shows the square upon which
the driving clutch is slipped. The spaces at the inner ends of this
indicate the clutches, or jaws, which mesh with corresponding slots
on the wheel hub and thus do the driving.

Fig. 446. Rear Axle, Showing Wheels Driven by Spur Gears

The dropped type of axles are neither all shaft-driven nor all
chain driven. Fig. 446 shows one that is of the spur-gear driven
type. The dropped axle bed C is of tubular form, and the differ-
ential case is dropped down on and slightly back of the rear axle, as
at B. From this case, two shafts A A extend out to the sides, driv-
ing the wheels through the medium of the spur gear D y which meshes
with internal gears within the wheel hubs (not shown). This type of
rear axle and drive is used on a number of the Fifth Avenue stages
in New York City.

Internal-Gear Drive for Trucks. The spur-gear driven type
just described is gaining rapidly for motor-truck use, because it has a
number of important advantages. Besides carrying the heavy load
on a member able to withstand any amount of overload, it materially
lightens the power-transmitting portion of the axle, which is enclosed
and therefore quiet. It is simple and inexpensive to construct and
repair. Fig. 447 shows a section through one of these axles, which is

247

Digitized by

Google

r>so

GASOLINE AUTOMOBILES

used on a very light truck of f-ton capacity. In this figure, it will be
noted that the load-carrying axle is behind the power-transmitting

shafts, consequently the for-
mer is straight. In Fig. 446,
the load carrying axle is in
front and consequently must
be bent down at the center.
This bend is a source of weak-
ness.

Full Floating Axle. Fig.
448 shows a full floating axle,
with the ends of the driving
shafts projecting beyond the
housing and carrying five
jaws which mesh with
five similar ones in the wheel
hubs and thus drive the
wheels. Unless the jaw end is
welded on to the shaft, this
makes a very expensive axle
despite its many good points.
Fig. 449 shows the rear con-
struction of a car with full
floating axle, with the brace
below it for the purpose of
strengthening the whole con-
struction. The large diam-
eter brake drums, shown close
to the wheels, are made of
pressed steel and are united
to the axle tubing, which is
also united to the. differential
housing, so that the whole
forms one large and continu-
ous piece, except where the
differential unit bolts on one

Fig. 447. Sectional Drawing through Internal-Gear .111 1

Drive Axle of Three-Quarter Ton Capacity side and the COVer On the

Courtety of Riiaxell Motor Axle Company, .« » T . .1 1 A i 1 * A

Detroit, Michigan other. rsote that the shaft

248

Digitized by

Google

GASOLINE AUTOMOBILES 587

has the driving clutches machined as an integral part, and that
removing the two shafts for a few inches makes it possible to unbolt

Fig. 448. Example of Full Floating Type of Axle

Fig. 449. Timken Full Floating Roar Axle, Showing Differential Remove
Courtesy of Timken-Detroit Axle Company, Detroit, Michigan

Fig. 450. Timken Full Floating Rear Axle with Spiral Bevel Gears

and remove the entire differential unit. For the sake of compari-
son, Fig. 450 shows an axle which differs from Fig. 449 only in having
spiral bevels substituted for the ordinary straight-tooth bevels. In

249

Digitized by

Google

588 GASOLINE AUTOMOBILES

Fig. 450, the differential unit is removable in the same manner as
in Fig. 449. One of the axle shafts, with its integral driving clutches,
and the differential cover are shown below. Note the two plugs in
the cover; the upper one is for filling the case with lubricant, while the
lower plug acts as a level indicator. When it is opened, heavy oil
or oil and grease combinations are put in the filling plug above until
the lubricant begins to flow out of the lower opening.

Three-Quarter Floating Axle. An interesting study in rear axle
design is seen in Fig. 451. This axle has a number of points in which

Fig. 451. Partial Section through Rear Axle of Case Car, Showing Construction
Courtesy of J. I. Case T. M. Company, Racine, Wisconsin

it differs from previously described forms. It is of the three-quarter
floating type. Note the enclosure of the driving shaft and the splines
at its forward end for the universal joint, also the housing for the joint
forming the torque member. The small roller bearing for the spigot
end of the driving shaft beyond the bevel pinion is unusual; so are
the diagonal distance rods, the spherical seat for the springs, the
combination of drawn-steel tubes, steel castings, and pressed-steel
cover for the axle housing. The wire wheel and its method of attach-
ment will be seen, also the double set of brakes, internal and externa'

250

Digitized by

Google

GASOLINE AUTOMOBILES 589

on the same dwim, with operating shafts for both supported from the
central part and ends of the axle housing.

Rear-Axle Housings. Rear-axle housings are usually of pressed
steel, although castings play a very important part and are some-
times used alone and sometimes in combination with other castings or
in combination with pressed steel. Aluminum, although not a depend-
able metal, is used quite a good deal for the purpose of saving weight,
as excess weight upon the rear axle is anything but desirable. In
one unusual but effective combination, the axle housing consists
of two malleable-iron castings joined together by means of bolts at
the centers, the brake drums being cast as a part of the tubes. While
not usual, this is safe practice, for malleable iron is tough and will
not break or splinter. It seldom is the case, however, that the axle
casing is reduced to as few parts as are shown here.

Welding Resorted To. Where the differential housing or brake
drums are of malleable iron, cast steel, or even of pressed steel, and it
is desired to unite them with the steel tubing forming the main part
of the shaft housing, welding is now universally used. Formerly,
it was good practice to make the casing a drive fit on the tube, riveting
it in place, or else soldering it in place, making doubly sure by using
rivets. Now, however, welding is resorted to, either the oxy-
acetylene, electric, or some other process being used.

In the axles shown in Figs. 449 and 450, it will be noted that
the axle shell is of pressed steel, to which the spring seats are bolted,
the remainder of the construction being formed by drawing. In Fig.
448, however, the construction is such as to necessitate making the
two halves longitudinally and then bolting or spot-welding them
together. Being machined after they are fastened together, it makes
as accurate a construction as the one-piece jobs, Figs. 449 and 450.

Effect of Differentials on Rear Axles. A differential gear,
sometimes called a balance, or compensating, gear, is a mechanism
which allows one wheel to travel faster than the other and which
at the same time gives a positive drive from the engine. This device
is a necessity in order to allow the car to go around a curve properly,
for in doing so the outer wheel must travel a greater distance than
the inner one during the same interval of time.

There are two forms of differential, the bevel type and the all-spur
type, the latter differing from the former only in the use of spur gears

251

Digitized by

Google

590

GASOLINE AUTOMOBILES

instead of bevel gears. The principle used in both is that a set of
gears are so held together that when a resistance ccmes upon one
part of the train of gears the whole train will stop revolving around
on a stationary axis and revolve around another gear as an axis, the
first gear, in the meantime, standing stationary, or practically so,
according to the amount of the resistance encountered. In the
bevel type, a pair of bevels are set horizontally. Between the bevels
is a spider with three or four arms, with a small bevel on the end of
each. These small bevels mesh with the larger bevels at the sides

and ordinarily stand still, ro-
tating around on the arm of
the spider as an axis by virtue
of the continued rotation of
the two side gears in opposite
directions. When one wheel
meets greater obstructions on
the road than the other, thus
holding it back, the shaft
which drives that wheel lags
behind the shaft driving the
other wheel and thus holds
back the horizontal gear at-
tached to the shaft. This
retarding movement allows
the other horizontal gear
more freedom to rotate. The
result is that the spider carry-
ing the smaller bevels rotates
around on its axis, thus imparting to the free gear attached to the free
wheel an additional motion, and to the free wheel a doubled speed,
while the retarded wheel has a lessened speed. This takes the car
around the corner without breaking the rear axle, as would be the
case without some such contrivance. The description of the bevel
differential action applies equally well to the spur type, except that
all gears are spurs.

The dividing of the rear axle is, of course, done to make a place
for the differential gear to work, and much time and thought have been
given to this subject in an endeavor to work out a substitute which

Fig. 452. Peculiar Differential Construction

252

Digitized by

Google

GASOLINE AUTOMOBILES 591

would permit the differential action and still allow the strengthening
of the rear axle. Fig. 452 shows one solution of the problem, which
has been worked out in such a way that the differential is moved
forward into the driving shaft. The rear axle shafts are thus greatly
strengthened, the designer being unhampered by the presence of the
differential in the rear axle. In this design, one side gear of the bevel-
gear differential is carried upon a shaft, and the other upon a tube
around the shaft. Then, at the rear axle, two sets of bevel gears
B^B* and A\At are used, A\ being driven by the main shaft, and driv-
ing the right-hand shaft through the gear A 2 ; while the other B* is
driven by the tube, and drives the left-hand shaft through the gear # 3 .
In this case the axle shafts are made much larger than in the ordinary
case, while the differential action is just the same.

Improved Forms of Differential. Lately, much work has been
done upon differentials to cause them to act as differentials should.
The present form of differential acts according to the amount of
resistance offered, but should act according to the distance traveled.
When no resistance is offered, all the power is transmitted to that
wheel, leaving the other stationary. This is just the opposite of the
desired effect. If a differential were constructed to work for distance
only, then, in the case of a wheel on ice or other slippery surface which
offered little or no resistance, both wheels would still be driven
equally, and the power transmitted to the one not on the ice would
pull the vehicle over it.

One way in which the differential action might be corrected is
by the use of helical gears and pinions instead of the usual bevel or
spur gears. In the M & S forms, this construction is used, I*ig. 453,
showing the form constructed by Brown-Lipe-Chapin. In this form,
each axle shaft carries a helical gear, and the differential spider carries
two helical pinions with radial axes and four additional pinions, each
of which meshes with one of the radial pinions and one of the gears
on the axle shafts. On a turn, the outer wheel tends to run ahead
of the inner and thus causes the nest of helical gears to revolve. All
gears and pinions have a right-hand 45-degree tooth, so that one wheel
may revolve the housing if the other is locked or held, but it is impos-
sible to turn the free road wheel by pulling on the housing. The
principle is the same as a worm steering gear in which the turning of
the hand wheel may be transmitted to the front wheels, but the gear

253

Digitized by

Google

592

GASOLINE AUTOMOBILES

cannot be operated from the wheel end, because the worm is irrevers-
ible. This differential is used to advantage to prevent spinning on
slippery ground and also to eliminate the skidding which the ofdinary
differential gives.

Another somewhat similar device has but two pairs of helical
pinions in addition to the two helical gears on the shafts, the axes of
each pair being set at an angle to the others. Thus, each helical
gear and its pinion form an irreversible gear combination, so that
movement cannot be transmitted through either in the reverse direc-
tion. This form fulfills the same conditions as the Brown-Lipe-
Chapin M &S form, as the construction is such that no motion can be

Fig. 453. The MAS Helical Gear Differential in Sections
Courtesy of Brown-Lipe-Chapin Company, Syracuse, New York

transmitted from the differential spider or housing to one of the wheels
alone.

The above principle is back of the gearless form, shown in Fig.
454, in which the result is achieved through ratchets instead of heli-
cal gears, the lack of gears giving it its name. In this form there are
two ratchets Y and Yl, which are keyed to the two axle shafts and
free to rotate independent of the housing. The round members
marked B are the interlocking pawls; the upper one is in a tooth of the
right-hand ratchet at the right and is driven by the contact face of
the driving sector X at the left. Thus, the right-hand ratchet is
being driven positively forward. The lower pawl is engaged at
the other end; so the left-hand ratchet is also being driven positively

254

Digitized by

Google

GASOLINE AUTOMOBILES 593

forward. On a turn, one wheel revolves faster than the other, say
the right, and causes the right-hand ratchet to move faster than the
differential housing, which can only go as fast as the other, or slow-
moving, wheel. Then, the right-hand ratchet pushes the end of
its pawl out of the tooth and gives it a free movement forward. As
soon as the wheels revolve at equal speeds, the spring pushes it back.
In the figure, the right-hand portion shows the original form in
perspective.

Possible Elimination of Differential. The whole modern tend-
ency is toward differential elimination. In the cycleqars and small
cars brought out in recent years, designers have been forced to get

Fig. 454. Sketches Showing Construction and Operation of Gearless Differential

along without it because of the demand for simplicity, light weight,
and low price. This effect has been obtained by the use of a pair of
driving belts, letting one slip more than the other; by the use of fric-
tion transmissions; by simply dividing the rear axle and letting one
side lag when there was resistance; by not dividing it and letting
one wheel drag; and in other ways. The evident success of these
small vehicles without a differential or any real substitute for one
has set designers to thinking about this subject again, and some
big cars without a differential, or with a more simple and less
expensive substitute for it, may appear in the near future.

Rear-Wheel Bearings. The bearings used on, rear axles differ
very little from those used on front axles. All forms are used — plain

255

Digitized by

Google

594 GASOLINE AUTOMOBILES

bearings, ball bearings, ball thrusts, roller bearings in both cylindrical
and tapered types, and all combinations of these. Thus, Figs. 445
and 452 show the exclusive and liberal use of ball bearings, while Fig.
451 shows all rollers of two kinds and ball bearings for thrust bear-
ings only. The two kinds of roller bearings are the tapered roller and
the flexible roller. Similarly, in Fig. 447, it will be noted that balls
are used with two kinds of rollers, straight solid rollers in the wheels
and flexible rollers in the differential case. Figs. 449 and 450 show
the exclusive use of the tapered roller type, a construction which is
gaining ground very rapidly, the same as in front axles, although,
formerly, ball bearings were most widely used. The materials
employed are similar to those used for front axles, which have been
previously described. Cases are made of all kinds of steel and iron —
pressed, drawn, cast, etc. — not to speak of crucible steel, malleable
iron, manganese bronze, phosphor bronze, aluminum, aluminum
alloys, and many combinations of these materials in twos and threes.
Rear-Axle Lubrication. Rear-axle lubrication is generally
automatic in so far as the central bevel or other gears and the differ-
ential housing are concerned. The housing usually has a form of
filling plug, or standpipe, which is used to fill the case with a form
of heavy grease every 5000 miles, or once each season. The case is
generally arranged so the filling plug works through and lubricates the
outer bearings on the axle shafts as well, with suitable provision
against this reaching the brake drums or other brake parts. The
wheel bearings either are cared for in this way or have a central
space which is filled with heavy grease once a season, being self-
lubricating from then on. Such other rear axle parts as need occa-
sional lubrication, as torque-rod pivots, brake-band supports, brake-
operating shafts, etc., are generally provided with external grease cups,
which arc given a turn once a week on the average. It is highly
important that the braking system be as well lubricated as the lubri-
cating means provided will allow.

REAR-AXLE TROUBLES AND REPAIRS

Jacking-Up Troubles. Much rear-axle work — practically all,
in fact — calls for the use of the jack. True, the full floating type of
axle can have its shaft removed without jacking, but, aside from
differential removal, there is little rear-axle trouble in which it is

256

Digitized by

Google

GASOLINE AUTOMOBILES 595

necessary to remove the shaft alone. In almost all cases, the axle
must be jacked up. Many axles have a truss rod under the center,
and this is in the way when jacking; however, this can be overcome.
Make from heavy bar iron a U-shaped piece like that shown on
top of the jack in Fig. 455, making the width of the slot just enough
to admit the truss rod. The height, too, should be as little as will
give contact with the under side of the axle housing.

Substitute for Jack. A good substitute for a jack is a form of
hoist, Fig. 456, which will pick up the whole rear end of the car at
once. This not only saves time and work, but holds the car level,
while jacking one wheel does not. Moreover, with a rig of this kind,
the car can be easily lifted so high that work underneath it may be
easily done. The usual hoisting blocks are very expensive, but the
above hoist can be easily made by the ingenious repair man. This
one was made from an old whiffletree with a chain attached at each
end. For the lower ends of the chains, a pair of hooks are made
sufficiently large to hook under and around the biggest frame to be
handled. With the center of the whiffletree fastened to the hook of
a block and tackle, the hoist is complete. By slinging the hooks
under the side members of the frame at the rear, it is an easy matter
to quickly lift that end of the chassis any distance desired.

Workstand Equipment. Next to raising the rear axle, the most
important thing is to support it in its elevated position. To leave it
on jacks is not satisfactory, for they will not raise the frame high
enough, and, furthermore, they are shaky and may easily let the whole
rear end fall over, doing considerable damage. With the overhead
hoist, the chains or ropes are in the way; so a stand is both a necessity
and a convenience. In Fig. 457, several types of stands are shown. A
is essentially a workstand, intended to hold the axle and part of the pro-
peller shaft while repair work is being done thereon. It consists of
a floor unit, or base, built in the form of an A, with six uprights let
into it, preferably mortised and tenoned for greater strength and
stiffness. Then, the four rear uprights are joined together for addi-
tional stiffness and rigidity. If casters are added on the ends, the
stand can be more conveniently handled around the shop.

The forms B are for more temporary work and consequently
need not be so well or so elaborately made. The little stand C is a
very handy type for all-around work. Stands of this kind with the

257

Digitized by

Google

596

GASOLINE AUTOMOBILES

top surface grooved for the axle are excellent to place under cars
which have been put in storage for the winter.

The stand D is, like A, a workstand pure and simple. In this,
however, the dropped-end members allow supporting the axle at

Fig. 455. Simple Arrangement for Avoiding
Rear-Axle Truss Rod

Fig. 456. Simple Automobile Frame Hoist

those points, while the elimination of central supports gives plenty
of room for truss rods. This type of stand would preferably be made
from metal, pressed steel or small angle irons being very good. Every

Fig. 457. Types of Handy Stands for Rear-Axle Repair Work

repair shop should have a considerable number and variety of stands,

made as the work demands them, to fit this particular class of work.

Universal- Joint Housings. Universal joints usually are covered

with leather casings which are packed with grease. These keep out

258

Digitized by

Google

GASOLINE AUTOMOBILES 597

the dirt and, consequently, lessen the wear, and also lubricate the
moving parts of the joints. A secondary function of the casings is to
render these joints noiseless. If a car is not equipped with them, it is
advisable for the owner to purchase them.

The v shape of these casings, when opened out flat, would be not
unlike that of two bottles with their flat bottoms set together, that
is, narrow at the top and bottom and wider at the middle. All along
both edges are eyelets for the lacing. The enlarged center fits around
the joint, while the small ends encircle the respective shafts. To apply
the casing, one end is placed around the shaft on one side of the joint,
and the lace started; then the lacing proceeds, gradually drawing
the ends together and around the joint. When this has been com-
pleted, and before the last end is closed, the whole is shoved back
along the first shaft a little way, and the center portion half filled
with a heavy grade of transmission grease. This done, the glove is
pulled back into place, and the work of lacing completed around the
second shaft. Both ends should be laced as tightly as possible, while
the middle part should be loose. Sometimes these , housings will
become worn and make a very annoying chatter on the road, even
when they are not sufficiently worn to warrant replacements. Under
such circumstances, the offending member may be wound with tire
tape held firmly in place in addition to its adhesive power by means of
a hose clamp, as shown in Fig. 458. The coupling is held tightly
enough to prevent the rattle and chatter, but not enough to interfere
with its action. While not a handsome job, it does the business,
stopping the noise effectively.

Rear Axle. Rear axles do such hard work and must stand up
under such a large portion of the load carried in the machine that
they offer many chances for wear, adjustment, or replacement.

Truss Rods. Truss rods hold the wheels in their correct ver-
tical relation to the road surface and to one another. If, through wear
or excessive loading, the axle sags so that the wheels tip in at the
top, presenting a knock-kneed appearance, the truss rods must be
tightened up. Usually, they are made with a turnbuckle set near one
end, a locknut on each side preventing movement. The turnbuckle
is threaded internally with a right-hand thread on one end and a left-
hand thread on the other, so that a movement of the turnbuckle draws
the two ends in toward one another, shortens the length of the rod,

259

Digitized by

Google

598

GASOLINE AUTOMOBILES

and thus pulls the lower parts of the wheels toward one another,
correcting the tipping at the top.

To adjust a sagging axle, loosen both locknuts, remembering
that one is right-handed and the other left. Then, with the wheels
jacked clear of the ground, tighten the turnbuckle. A lonp> square
should be procured or made so that the wheel inclinations may be
measured before and after. Placing the square on the ground or
floor, which should be selected so as to be perfectly level, the turn-
buckle should be moved until the tops appear to lean outward about
£ inch — some makers advise more.

It should be borne in mind that even if the wheels and axle do
not show the need of truss rod adjustment, if this rod be loose, it
will become very noisy and rattle a great deal, as the rear axle sus-

tains a great amount of

j \ |\ jouncing. Moreover, this

_s , l r , noise and rattle, if not

taken up, will cause
wear, which cannot be
taken up.

Disassembling Rear
Construction. In disas-
sembling the rear con-
struction for purposes of
adjustment or repair, the
repair man should be
careful to mark all parts. Those parts which have been running
together for several thousand miles act better and with less friction
than would those which have never run together, despite the fact that
the duplicate parts are supposed to be alike and interchangeable.
It is therefore suggested that separate boxes be provided for the parts
taken from the two ends or sides. The method of disassembling is
about as follows: Jack up the axle, replacing the jack with small
horses or blocks of wood if possible. Take off the hub caps, then
free the wheels and take them off. Disconnect the brake-operating
rods and levers and remove them from the car, marking them care-
fully. Spread the brake shoes apart, loosen the springs at one side,
take out the springs, and then loosen and take out the brake
shoes themselves. Remove the brake operating shaft with the cams;

Tire Tape

Fig. 458. Easy Method of Quieting Noisy Universal-
Joint Housings
Courtesy of "Motor World"

260

Digitized by

Google

CAROLINE AUTOMOBILES 500

then disconnect the spring bolts and jack up the chassis, using the
spring for a support. Disconnect all torsion or radius rods and take
off the grease boot around the universal joint in the driving shaft.
Open this joint and disconnect the shaft. Take this off, and if the
spring bolts have been removed, the rear axle will be free. Pull it
out from under the chassis, and, if desired, further disassembling may
be done more easily with the member clamped in a vice or laid on a
bench.

Assembling. In assembling, almost the reverse of this process
is followed, the parts going together in the opposite manner from
that in which they were taken down.

Noisy Bevel Gears. If the bevel gears in the rear axle are
noisy, the'time to fix them is when the axle is disassembled, as this
is quite a job. In general, bevel gears make a noise because they
are poorly cut, because they are not set correctly with relation to
each other, or because the teeth have become cut, or chipped, by
some foreign material which has been forced between them.

In the first case, there is little the amateur can do beyond
making the best possible adjustment and smoothing off any visible
roughness. In the second case, it is simply a matter of setting one
gear closer to or farther from the other by means of the adjustment
provided. When the axle is disassembled, and all parts are readily
accessible, it will be found that there is a notched nut on either side
of each of the bevels; there should be a wrench in the tool kit to fit
this. It is then a simple matter to move one outward and the other
inward in either pair, according to which needs the adjustment.
In case the teeth have become chipped, the projections should be
smoothed down with a fine file, while the sharp edges of the cuts
should be dressed in the same manner.

Packard Bevel Adjustment. Although strictly a transmission
trouble, the older Packard cars have the transmission located on the
rear axle, and this position made the adjustment of the bevel pinion
difficult. For another thing, the shaft is very short and hard to hold.
If the sliding gear on the shaft is meshed with the internal gear
attached to the other end of the bevel-pinion unit, the latter will hold
firmly, but there will still be a little play between the teeth. It is
necessary to take this up, as otherwise the repair man would mistake
this play for play in the bevel driving gear. It can be taken up as

261

Digitized by

Google

600

GASOLINE AUTOMOBILES

follows : Take an old sliding-gear unit from one of these transmissions,
remove one of the teeth and slide the gear into position for meshing
with the space at the top between two teeth on the good gear. Drive
a pin in where the tooth has been removed, and this will fix the two
firmly together without a particle of play. Then, by removing the
cover from the differential housing, the bevels can be tested for play.
Fig. 459 shows the transmission, bevel gears, and axle parts, also the
gear with the tooth removed and replaced by a pin, so that the whole
process will be clear.

Repair for Broken Spring Clips, The springs are held down on
the axles by means of spring clips, which are simply U-shaped bolts

[Fin. 450. Diagram of Packard Axle and Transmission to Show

Adjustment of Bevel Pinion

Courtesy of " Motor World"

with the inside width of the U equal to the width of the spring.
Occasionally, these will break when they cannot be replaced or new
ones forged. Under such circumstances, a repair such as used by
one man, shown in Fig. 460, will always get the car home or to a
garage where a better one can be made. This method of repair
consists of a pair of flat plates, one above the spring, the other below
the axle, with holes drilled in the corners to take four long carriage
bolts, which happened to be handy. The plates were put on, bolts
put in and tightened up, and the car was ready to run. Although
an I-section axle is shown, this method of repair would work just
as well on a round axle or on one of any other shape.

262

Digitized by

Google

GASOLINE AUTOMOBILES 601

Lining Up Axles. In such a repair, however, the main thing
is to get the rear axle lined up correctly, which is not an easy job.
This may be done in the following manner: Get the car standing level
on a nice clean smooth floor; hold a large metal square with a plumb
bob hanging down over its short edge against the side of the frame.
Move the square forward until the line just touches the rear axle at
some set distance out from the frame, say 3 inches, as shown iti Fig.
461. Then notice the distance this line is forward from the rear end
of the frame. In the sketch it is 16 inches. Transfer the square and
plumb bob to the other side and repeat. Here it will be found that the
distance from the rear end of the frame is either more or less. In the
sketch it is shown at 18 inches; so the difference, 2 inches, shows that
the axle is out of alignment
that much or half that, 1
inch at each end.

This axle is straightened
by loosening the spring bolts
and pushing one side back
the distance apparently
needed, then fastening
tightly and checking up. If
not correct, try again, using
judgment as to which side
should be moved. When

t% n • /> i i i Fig 46 °. H ° w Spring Clips Are Replaced

finally satisfied that the rear »n Emergency

, . .,, ,, m Courtesy of " Motor World"

axle is square with the frame,

it is well to check this against the center-to-center distance of the
wheels on each side. This is done by setting the front wheels exactly
straight and then measuring from the center of the right front to the
center of the right rear wheel. Then go over to the other side and
measure the center-to-center distance of the left wheels. The two
axles should agree exactly. If they do not, the rear axle prusumably
needs more adjustment for squareness.

Taking Out Bend in Axle. A simple method of repairing an axle
which has been bent, but a method which is only temporary in that it
is not accurate enough to give a job which could be called final, is
that indicated in Fig. 462. The axle was bent when the hub struck
an obstruction in the road, and it had to be straightened immediately.

263

Digitized by

Google

602

GASOLINE AUTOMOBILES

A short length of 2 x 4 timber was cut to be a tight fit between the
upper side of the hub cap and the roof beam. Then a jack under the

\y ,

Fig. 461. Method of Checking up Uear-Axle Alignment with Square and Plumb Bob

axle at the point of the bead was raised. As the jack raised the axle,
and the wood beam held the hub down, enough pressure was exerted

to force the axle to give at the

jPoor

Fig. 402.

One Way of Straightening Rear
Axle Quickly

bend and return as nearly as
possible to its original straight-
ness. It was a quick and easy
repair of the rough and ready
order, which served when time
was worth more than anything
else; but it is a method which
would not be advised or recom-
mended when there was suffi-
cient time to properly
straighten the axle.

Locating Trouble. Many
times, a car may be brought
in for rear-axle repair on which
the repair man cannot find any
trouble. Many axles often
develop an elusive hum, or
grinding noise, which not only
defies location, but is not con-
tinuous. The writer had such
a case brought to him at one

264

Digitized by

Google

GASOLINE AUTOMOBILES 603

time, and was sure that the bevel gears were out of alignment and
were cutting each other. It was a low-pitched whine which was
not apparent at low speeds, but began to be heard around 18 to 20
miles an hour, and at times was very apparent. The noise was very
annoying, but tearing down the rear construction showed absolutely
no trouble; so the noise could not be at that point. Sometime later
the noise was definitely located in a pair of worn speedometer
gears on the right end of the front axle.

A good way to listen to rear axle hums out on the road is to lay
back over the rear end of the car, Fig. 463, with the head against
the top of the seat and project-
ing over slightly, and with the
hands cupped in front of the
ears, so as to catch every noise
that arises. The larger sketch
shows the general scheme, the
small inset giving the method
of holding the hands. When
the sound arising from the axle
is a steady hum, the gears are
in good condition and well
adjusted. If this sound is inter-
rupted occasionally by a sharper,
harsher note, it may be assumed
that there is a point in one

» , , - , , Fig. 463. Listening for Rear-Axle Noises

of the gears or on one of the

shafts where things are not as they should be. By trying the car
at starting, slowing down, running at various speeds, and coasting,
this noise can be tied to something more definite, some fixed method
of happening. In advance of actual repair work, including tearing
down the whole axle, the gears can be adjusted. This can generally
be done from outside the axle casing and without a great deal of work.
If the adjustment makes matters worse, it can be reversed, or if it
improves the situation, the adjusting can be continued, a little at a
time, until the noise gradually disappears.

Checking Up Ford Axles. Many cases of Ford bent rear axles
can be fixed without taking down the whole construction. The prin-
cipal point is to find out how much and which way the axle is bent.

265

Digitized by

Google

604

GASOLINE AUTOMOBILES

By removing the wheel on the bent side and placing the rig shown in
Fig. 464 on the axle end, the extent of the trouble can be indicated by
the axle itself. The iron rod is long and stiff, with its outer end
pointed, and is fastened permanently to an old Ford hub. The
rig is placed on the axle and held by the axle nut, but without the
key, as the axle must be free to turn inside the hub. With the pointed
end of the rod resting on the floor and with high gear engaged, have
some one turn the engine over slowly, so as to turn the axle shaft
around. As it revolves, the hub will be moved, and the pointed end
on the floor will indicate the extent of the bend. By marking the
two extreme points and dividing the distance between them, the
center is found. Then a rod can be used as a bar to bend the axle,
until the pointed rod end is exactly on the center mark. A little

practice with this rig will
enable a workman to
straighten out a Ford rear
axle in about the time it
takes to tell it.

BRAKES
Function of Brake.

Next to power, applied
through the correct form of
gearing, and its final suita-
ble drive to the road wheels,
nothing is of more importance than the ability to stop the vehicle at
will. One medium through which this is done, and which ordinarily
suffices, is the shutting off of the source of power — in this case, the
gasoline and the spark which is used to ignite its vapor. This will not
always suffice, however, for the ordinary car possesses the ability to
run at a speed of 40 miles per hour or upward, and weighs from 2000
pounds (one ton) upward to 4000 pounds (two tons). This combi-
nation makes for a large force of inertia, which will result in the car
running for many yards, even hundreds of yards, after the power is
shut off. It is for this reason that we must have a mechanical
means of absorbing this inertia, or of snubbing the forward move-
ment of the car. This is the function of the brakes, as fitted to
the modern car.

<£=

Maximum
Marks on Floor.

Hub

(Half

\Wou

Fig. 464. Diagram Showing Method of Checking
Up Ford Axles

266

Digitized by

Google

GASOLINE AUTOMOBILES 605

Engine as a Brake. Although disregarded in any summary of
brakes, the engine is the best brake possible, granting that the driver
knows how to get the best results without doing any damage. The
ordinary engine has a compression of from 60 pounds to 70 pounds per
square inch, which is practically the pressure available when it is used
as a brake. Since this is more pressure than any other type, or form,
of brake will yield, its usefulness is self-evident.

Classification. Brakes are usually divided into two classes,
differing mainly in location — the internal expanding and the external
contracting. To these a third class should be added, because it par-
takes of the nature of both, yet differs from each one. This is the
railway type of brake with removable shoes of metal, differing from
the band type in that no attempt is made to cover the whole or even
the greater part of the circular surface, but simply a small portion of it,
against which a shoe is forced with a very high pressure. Both the
other types are subject to division into other classes, the first into
three subdivisions according to operating means, viz, cain, toggle, and
scissors action.

Brakes are generally divided according to their location, as shaft
and rear axle. The shaft brake at one time virtually went out of use,
but it is now being revived. The marked swing toward the unit
power plant, together with its simplification, lightening, and elimina-
tion tendencies, has produced a situation where a brake drum just
back of the power and gear unit can be operated by the hand lever
and a very short rod. In this way much weight and many parts are
saved. An indirect advantage is that the brake is more accessible.
With the worm drive, there is a marked tendency back to the shaft
brake, particularly on motor trucks. Again, "in the last few years,
some work has been done with pneumatic, hydraulic, and electric
forms of brake. With air under pressure for starting, and with water
or electricity as needed for starting or for other purposes, it is a simple
matter to utilize the same agency for braking, providing such use does
not add too much complication and, at the same time, that it
will give a superior method of snubbing the forward movement of the
car. In case none of these advantages are realized, there will be no
particular advantage in adding new forms of brake.

External-Contracting Brakes. This class of brakes is divided
nto but two types, viz, single- and double-acting. In the first, an

267

Digitized by

Google

606

GASOLINE AUTOMOBILES

end of a simple band is anchored at some external point, while the
other, or free end, is pulled. This results in the anchorage sustaining
as much pull as is given to th^ operating end, that is, all pull is trans-
mitted directly to the anchorage. This disadvantage has resulted
in this form becoming nearly obsolete.

Any brake of the true dpuble-acting type will work equally well
acting forward or backward. The differential brake, Fig. 465,
shows this clearly. The external band is hung from the main frame
by means of a stout link which is free to turn. The band itself
is of very thin sheet steel, lined with some form of non-burnable belt-
ing. The ends carry drop forgings, to which the operating levers are
attached. These are so shaped that the pull is evenly divided between
the two sides of the band. This will be made apparent by considering

that a pull on the lever H will
result in two motions, neither
one complete, since each depends
upon the other. First, there will
be a motion of the upper band
end B about the extremity of the
lower one as a pivot, followed by
a movement of the lower end,
pivot and all, about B as a second
pivot point. These two motions
result in a double clamping action
which is supposed to distribute evenly over the surface. In order to
insure even distribution, the lining is grooved, or divided, into
sections.

Usually, chain-driven cars have a different brake location from a
car with shaft drive. The chain-driven cars have three sets of brakes :
one on the main shaft, one pair on the countershaft, and another pair
on the rear wheels, as shown in Fig. 466.

Internal-Expanding Brakes. While the contracting-band brake
is well thought of, the internal-expanding form is rapidly displacing
it, for the reason that experienced drivers think more of it. In Fig. 467
will be seen a modern form of the internal brake, namely, the use of
both brakes as internal, but placed side by side in the same drum.
This is a tendency which seems to be gaining in favor. The car is the
Owen Magnetic, one of the most expensive and luxurious; so the use

Fig. 465. Brake on Main Shaft of
Benz (German) Car

Digitized by

Google

GASOLINE AUTOMOBILES

607

of side-by-side internal brakes here must be attributed to superiority
rather than to a desire to save in money or in parts.

A considerable number of foreign cars, which are used in moun-
tainous countries, show a method of cooling the brake drums by means
of external cooling flanges. In some makes, even a water drip is
provided for extremely hilly country.

More modern practice shows no tendency to place all of the eggs
in one basket, both forms of brake being employed together and upon
the same car, usually also upon the same brake drum, one set working

Fig. 466. Bens Countershaft Brakes for Chain-Driven Car

upon the exterior, while the other works upon the inside. In Fig. 468,
which shows the rear-axle brakes of the larger cars made by the
Peerless Motor Car Company, this mechanism is plainly illustrated,
both the brakes being shown, although the drum upon which they
work has been removed. The parts are all named so as to be self-
explanatory. In this construction, the inner, or expanding, band is
operated by a cam. In the brake sets put out by the Timken Roller
Bearing Company, of Detroit, Michigan, in connection with their bear-
ings and axles, the toggle action is used, Fig. 469. The constructional
drawings, Figs. 470 and 471, showing the brakes used on the Reo
car, manufactured by the Reo Motor Car Company, of Lanaujg,

269

Digitized by

Google

Digitized by

Google

GASOLINE AUTOMOBILES

609

In general, however, when both brakes are placed on the rear
wheels, one external and of the contracting-band type, and the other
internal and of the expanding-shoe
form, modern practice calls for a
cam to operate the latter, oper-
ating directly upon the ends of
the two halves of the shoe, while
levers operate the band so as to
get a double contracting motion.

Some modern brakes may be
seen in Figs. 472, 473, and 474.
The first shows a system such as
just described; the second shows
a stiff metal shoe in both types;
and the last a pair of shoes set
side by side. In addition, the last-
named includes a new thought in Fi«. 469. Timken Double Rear-Axle Brake

Fig. 470. Section Showing Construction
of Reo Brakes

Fig. 471. Drawing Showing Method of
Operating Reo Brakes
Couritry of Reo Motor Car Company, Lansing, Michigan

that the brake shoes are floated on their supporting pins, as shown.
This makes the bearing of the shoes certain when expanded against
every portion of the drum, as the shoes can "float" until they fit exactly.

271

Digitized by

Google

610 GASOLINE AUTOMOBILES

Double Brake Drum for Safety. A very important feature is
pointed out in Fig. 472, namely, that of safety. Where both brakes
work on a common drum, one inside and the other outside, the con-
tinuous use of the service brake (whether internal or external) heats
up the drum to such an extent that when an emergency arises calling
for the application of the other brake it will not grip on the hot
drum, being thoroughly heated itself. The double drum allows air
circulation and constant cooling.

Methods of Brake Operation. While it is generally thought that
round iron rods are the universal means of brake operation, such is not
the case. Many brakes on excellent cars are worked, as the illus-
trations show, by means of cables. This idea is even carried so far

Fig. 472. Double Brake Drum Used on Locomobile Can

that brakes have been fitted to operate through the medium of ropes.
Chains of small diameter have also been used, as well as combinations
of rods, chains, cables, and ropes.

A lever-operated braking system of a well-known medium-
priced car is shown in the outline sketch, Fig. 475. In this system the
forward part of each half is worked by rods moved by means of
pedals, but the rear part of each half is actuated by means of cables.
Cables have one advantage over rods in a situation like this — the
diagonal pull with a stiff rod might, in time, act to pull the brakes side-
Digitized by VjOOQlC

GASOLINE AUTOMOBILES

611

Fig. 473. Brakes and Rear Construction of Pierce Cars
Courtesy of Pierce-Arrow Motor Car Company, Buffalo, New York

Fig. 474. Side-by-Side Arrangement of Brakes on American Rear Axle
Courtesy of American Ball Bearing Company, Cleveland, Ohio

273

Digitized by

Google

612

GASOLINE AUTOMOBILES

wise off their respective brake drums, the cable, being more flexible,
gives less danger of this.

This method of operation seems to be gaining favor because of
its simplicity, which eliminates parts that add weight and gives
immediate results when the parts are properly adjusted. The recent
New York show revealed a surprising number of small and medium
size cars with cable-operated brakes. An inspection of these cars
showed a mechanical cleanliness which was lacking in many others of
the same class on which an attempt was made to reduce braking rods

Pig. 475. Layout of Brake-Operating System Using Cables

and levers to a minimum, with consequent bent levers, bent or crooked
rods, brakes worked from an angle, and other unmechanical ideas.
Fully as important as the operating means is the matter of
equalizing the pull so that the same force is exerted upon both wheels
at once. This action is influential in causing side-slip or skidding,
which may result fatally. To equalize the force was one reason for
the use of cables, although the more up-to-date way is to attach the
operating lever to the center of a long bar, to the extremities of which
the brakes themselves are fastened. A pull on the bar is then divided
into two different pulls on the brakes, the division being made
automatically and according to their respective needs. This is an

274

Digitized by

Google

GASOLINE AUTOMOBILES 613

important point, and one that should be looked after in the purchase
of a new car.

Brake Adjustments. In recent years much of the brake improve-
ment has been that of making adjustments easier and of making the
adjusting parts more accessible. This can be noted in such a case as
the Locomobile, Fig. 472, where' the special adjusting handle on the
brake is carried to such a height as to make the turning of it an easy
matter. Similarly, on the Pierce, Fig. 473, it will be noted that
there is provision for increasing or decreasing the closeness of the
shoes to the drum, which is easily accessible.

Brake Lubrication. As for the actual brake surfaces, there is no
such thing as lubrication. The surfaces should be kept as dry and
clean as possible. If grease or oil gets out from the axle or other
lubricated parts onto them, there is sure to be trouble. The operating
rods and levers, however, should have fairly careful lubrication, for
which purpose the best makers provide grease or oil cups at all vitatl
points. If these be neglected, a connection may stick, so that when
an emergency arises the brake will not act properly and an accident
may result.

Recent Developments. In the last few years, the only new
ideas advanced in the way of brakes concern front-wheel braking
and electric brakes. The former were used quite extensively abroad
in 1913, but in 1914 they seemed to drop back; this, too, despite the
fact that the Grand Prix race of the latter year showed in a marked
manner the need for and special application of front-wheel brakes to
racing and high-speed cars.

Electric Brakes. A very efficient and compact brake, appli-
cable with a small amount of work to any chassis having a storage
battery, is the Hartford, shown in Fig. 476, while Fig. 477 shows the
operating lever as it is placed beneath the steering wheel, and Fig. 478
shows the wiring system. This brake consists, in substance, of a
small reversible electric motor, to which a 100 to 1 worm reduction is
attached. Attached to the drum is a cable, which is fastened to the
usual brake equalizer. Turning the current into the motor from
the storage battery rotates the drum, winds up the cable, and applies
the brake. The complete outfit weighs but 35 pounds. The motor has
a slipping clutch, set to operate at 1000 pounds pull, at which it draws
40 amperes of current from the battery for two-fifths of a second.

275

Digitized by

Google

614

GASOLINE AUTOMOBILES

Fig. 476. Exterior of Motor Which Forms Central

Unit of Hartford Electric Brake

Courtesy of Hartford Suspension Company,

Jersey City, New Jersey

Fig. 477. Hand Lever on Steering Post for
Operating Hartford Electric Brake

DRAKE MOTOR

Fig. 478. Wiring Diagram for Hartford
Electric Brake

In use, it replaces the emer-
gency hand-operating lever,
and is said to be able to pull
a heavy car going 50 miles an
hour down to less than 15 in
a distance of less than 35
feet. The pull is so great
that the brake drums are
oiled to prevent heating and
possible seizing.

Hydraulic Brakes. On
the newer Knox tractors, a
brake of very large size is
made even more powerful by
hydraulic operation. This
brake is shown in Fig. 479.
At the left will be seen the
usual brake lever attached to
a small piston in a chamber
full of liquid. This chamber
communicates through the
medium of a valve normally
held closed by a spring, with
a passage above, and that, in
turn, communicates with the
pipes leading to the brake-
operating cylinder. This cyl-
inder has a stout rod attached
to a good size plunger, back
of which the liquid (oil) is
introduced. When liquid is
forced in, the plunger moves
forward, forcing the rod out
and, through connecting rods
and levers, applying the
brakes. As will be seen in
the drawing at the right,
these brakes, which are of the

276

Digitized by

Google

GASOLINE AUTOMOBILES 615

internal-expanding type, are exceptional in size and work against
steel drums attached directly to the wheel spokes.

When the lever is drawn back in the usual manner, liquid is
forced upward through the top passage to and through the pipes
into the other cylinder, forcing the plunger to move, and, through the
movement of the plunger, the brakes are applied. The return of the
fluid is not shown, but it is assumed that this is through a simple pipe
connection from the plunger cylinder to the hand-operated piston with
a check valve. Should the initial movement of the lever fail to apply
the. brakes sufficiently, the driver can let the lever come forward and
then pull it back again; in so doing he will take into his lever cylinder

Fi«. 479. Layout of Hydraulic Brakes Used on Knox Tractor
Courtesy of Knox Motors Company, Springfield, Massachusetts

more liquid from below without releasing the brakes. Then, when
this extra quantity is forced through, the plunger is moved even
farther forward, and the brakes applied more forcibly. The brakes
are 20 inches in diameter by 6 J inches wide.

Vacuum Brakes. The latest development in the line of braking
systems is the Prest-O-Lite vacuum brake. This brake consists of a
controlling valve, a vacuum chamber, piping from the inlet manifold
to the valve and thence to vacuum chamber, and a foot button or finger
lever on the steering post to operate the valve and thus put the
system into use. The rod in the vacuum chamber is connected up
to the service brakes, the system thus taking the place of the usual
pedal and foot operation. The chassis sketch, Fig. 480, shows this

*** Digitized by

Google

616 GASOLINE AUTOMOBILES

in plan, A being the controlling valve, BB the tubing from the inlet
manifold to the controlling valve and from it to the vacuum chamber
C. The rod D from the chamber will be seen connected to the
service-brake rods and levers.

In Fig. 480 the method of operating the system is not shown, but
in Fig. 481 the foot lever can be seen with its connections. When
this is pressed, the controller valve is opened and the engine, as it rims,
draws air out of the chamber C in back of the plunger, gradually
creating a vacuum, so that the plunger is forced to move forward to
compensate for this. As the plunger carries a tail rod projecting
through the end of the cylinder, and as this rod is connected up to the
braking system, but with a big leverage, the movement of the plunger

Fig. 480. Chassis Plan Showing Application of Preet-O-Lite Vacuum Brake
Courtesy of Prest-O-LiU Company, Indianapolis, Indiana

applies the brakes. The amount of brake application depends upon
the amount of suction, and that is governed by the amount the valve
is opened by the finger lever or foot button. Consequently, with this
new brake, the bucking effort can be varied to suit the conditions.
It is said that the leverage arrangement is such that 10 pounds
per square inch in the intake manifold will produce 1000 pounds
braking effort at the rear wheels. This means that the brakes could
be used with the engine running very slowly. The system is applied
to the service brakes because a brake is sometimes needed when the
engine is not running, as when coasting down a hill with the engine
shut off and clutch out, or with the car standing and engine shut off,
etc. ; also because it is the most used system, and it is felt that the
simple finger pressure and gradual or instantaneous application

278

Digitized by

Google

GASOLINE AUTOMOBILES 617

possibilities of the new form make it more desirable as a service or
running brake.

Whatever advantages may develop in the use of these special
types, it is certain that the next few years will see considerable
improvement in braking, so that a greater force may be applied more
quickly, and thus act to prevent a large part of the accidents for
which automobile owners and drivers are now unjustly blamed.

BRAKE TROUBLES AND REPAIRS
Dragging Brakes. Probably the first trouble in the way of
brakes is that of dragging, that is, braking surface constantly in

Fig. 481. Foot Button for Operating Vacuum Brake

contact with the brake drum. This should not be the case, as springs
are usually provided to hold the brake bands off the drums. Look for
these springs and see if they are in good condition. One or both of
the brake bands may be bent so that the band touches the drum at a
single point.

Another kind of dragging is that in which the brakes are adjusted
too tightly — so tightly, in fact, that they are working all the time.
In operating the car, there will be a noticeable lack of power and
speed, while the rear axle will heat constantly. This can be detected
by raising either rear wheel or both by means of a jack, a quick

279

Digitized by

Google

618

GASOLINE AUTOMOBILES

lifting arrangement, or a crane, and then spinning the wheels. If
the brakes are dragging, they will not turn freely.

All that is needed to remedy this trouble is a better adjustment.
For the new man, however, it is a nice little trick to adjust a pair of
brakes so that they will take hold the instant the foot touches the
pedal, that they will apply exactly the same pressure on the two
wheels, and yet will not run so loose as to rattle nor so tight as to drag.
Dummy Brake Drum Useful. Where a great deal of brake
work is to be done, particularly in a shop where the greater part of
the cars are of one make, and the brakes all of one size, a great deal
of time and trouble can be saved by having a set of test drums. An
ordinary brake drum with a section cut out so that the action inside
may be observed is all that is necessary, except that it should be
mounted suitably. As shown in Fig. 482, it is well to fit a pair of

handles to the brake drum
to assist in turning the
drum when the adjustment
is being made. The real
saving consists of the work
which is saved in putting
on and taking off the heavy
and bulky wheel each time
when the adjustment is
changed. The test drum
is put on instead, and being small and light and equipped with handles,
it is easily and quickly lifted on and off. This enables the workman
to make a better and more accurate adjustment than he would when
the heavy wheel had to be handled, while the cut-out sectibn enables
him to see the inside working also and thus correct any defects or
troubles at this point.

To Stop Brake Chattering. It is claimed that the chattering
of brakes is caused by having the brake lining, particularly of internal
hand brakes, extend over too large a portion of the circumference of
the drum. The result is that with a well-adjusted system, as soon as
fQrce is applied, the lining close to the operating cam and that on
the opposite side close to the pin on which the brake shoes are
pivoted jumps against the drum and then away from it. This
jumping of the brake shoe, which is the result of too much lining, is

Fig. 482. Dummy Brake Drum for Adjustment Work

280

Digitized by

Google

GASOLINE AUTOMOBILES

619

Lining Cut FJ**0\j Hern

what causes the chattering. If the lining is cut away for about 30
degrees on either side of a line drawn from cam to pivot pin, as shown
in Fig. 483, it is said that this chattering will stop immediately.
If further trouble of the
same kind results, bevel off
the outside ends of the lining
at the two 30-degree points.

A number of sugges-
tions in the way of possible
brake troubles, particularly
on the side-by-side form of
internal-expanding brakes,
are indicated in Fig. 484.
This shows a semi-floating
form of rear axle wi*L the
two sets of brakes and oper-
ating shaft and levers. A
number of suggestions are offered for this form, the most important
of which is: "Renew worn brake lining and broken cr loose rivets."

When a brake lining is worn, the proceeding is much the same
as with a clutch leather, with the exception that whereas the latter

Clean fl- refill ora«

\ find Here

Fig. 483. Method of Eliminating Brake Chattering
on Internal-Expanding Brakes

Fig. 484. Brake Troubles Illustrated

must have a curved shape, the former can be perfectly straight and
flat. This simplifies the cutting; but most brake linings are made of
special heatproof asbestos composition which is made in standard
widths to fit all brakes, so the cutting of leather brake bands is not
often necessary.

281

Digitized by

Google

620

GASOLINE AUTOMOBILES

Eliminating Noises. Many times the brake rods and levers
wear just enough to rattle and make a noise when running over
rough roads or cobblestone pavements, but hardly enough to war-
rant replacing them. The replacement depends on the accuracy
with which they work, the age and value of the car, and the attitude
of the owner. In a case where the owner does not desire to replace
rattling rods, the noise can be prevented by means of springs, winding
with tape, string, etc.

If the rod crosses a frame cross-member or is near any other
metal part, and its length or looseness at the ends is such that it can

be shaken into contact there, a rattle
will result at that point. This can
be remedied or rather deadened by
wrapping one part or the other. For
this purpose, string or twine can be
used as on a baseball bat or tennis
racket handle, winding it together
closely so as to make a continuous
covering. Tire or similar tape may
also be utilized. When this is done,
it is necessary to lap one layer partly
over the next in order to keep the
whole tight and neat. It has the ad-
ditional advantage of giving a greater
thickness and thus greater resistance
to wear. If none of these remedies
Aua^ent are available or sufficient, burlap in
strips or other cloth may be used,
putting this on in overlapping layers the same as the tape.
The springs should be put on in such a way as to take up the
lost motion and hold the worn parts closer together. The rattle
occurs when the movement of the car alternately separates and pulls
together the two parts, a noise occurring at each motion. The
spring should be put on so as to oppose this motion, acting really
as a new bushing or pin, the pull coming first upon the spring and then
upon the bushing or pin.

Stretching Brake Lining. Brake lining should be put on as
tightly as possible, and the knowledge of this, combined with the

Fig. 485. Sketch Showing
Stretching Brake Linings before

Courtesy of " Motor World

282

Digitized by

Google

GASOLINE AUTOMOBILES

621

•Cutter

difficulty of doing it by hand, makes the stretching device shown in
Fig. 485 particularly valuable when much brake relining is to be done.
This is a simple pulling clamp, which is attached to one end of the
lining after the first end has been riveted in place. Then it is
attached to the end of the shoe, and the nut tightened so as to stretch
it. When it has been stretched sufficiently, the other rivets can be
put in, or the shoe and band with the stretches in place can be laid
aside for a while to stretch it fully before fastening. Obviously, this
is applicable only to the internal-
expanding form, but the hook
and clamp can be used on any
size or type of expanding brake.
Truing Brake Drums. When
both inside and outside surfaces
of the brake drum are used, it is
highly important that both be
true. Since they do not stay that
way long, the repair shop should
be equipped to true them up
quickly. A truing device is shoVn
in Fig. 486, with the wheel and
brake drum in place on it. One
feature of the device is that brake
drums need not be removed from
the wheel. The device consists
of a metal base having a strong
and stiff wooden pier with a hori-
zontal arm the exact size of the
axle end mounted on it. The
wheels are placed on the arm and
rest on it the same as on the axle when on the car. The tool is
double, with two ends, one of which cuts the inside surface of the
drum, while the other cuts the outer surface. At the center this tool
is attached to a heavy casting, bored out to slide over the shaft and
with a key fitted into a key way in the shaft to prevent the tool from
rotating. The end of the arm is threaded, and a large nut with two
long arms is screwed up against the tool at the start, and then it is
used to feed the latter across the work.

Metal

Fig. 486. Apparatus for Truing Inside and

Outside of Brake Drum in Place on Wheel

Courtesy of "Motor World"

283

Digitized by

Google

622 GASOLINE AUTOMOBILES

This is subject to a number of modifications to fit it to the various
sizes and shapes of brake drum. Another method is to use the lathe,
provided the shop is equipped with a lathe large enough. By making
a mandrel the same as the axle spindle and having a pair of dummy
bearings to place on it, the brake drum can be slipped on to the
mandrel, and the whole put right into the lathe. The surface, either
internal or external or both, can then be trued up exactly as if the
drum were on the axle.

WHEELS

Broadly speaking, there are but two kinds of wheels according
to the service each is to render, pleasure-car wheels and commercial-
car wheels. The former may be further subdivided into wood, wire,
and spring wheels; while the latter may be divided into wood, steel,
and spring wheels. Some of the commercial vehicle wheels are
further divisible, as steel wheels into sheet steel and cast steel;
wood into spoked and solid; and spring wheels into various types.

Wheel Sizes. Wheels are used on automobiles, in combination
with the tires, to afford a resilient and yielding contact with the
surface of the road, so that people may ride with comfort. Therefore
a wheel whose size is such as to yield the most comfort to the car
occupants with due regard to its cost relative to the cost of the vehicle
is the wheel to use. The cost of the wheels themselves, however,
is so small in comparison with the cost of the pneumatic tires which
are used on them as to be completely overshadowed by the latter.

Where comfort is sought as the prime requisite, cost becomes an
accessory. The larger the wheel used the better the car will ride,
and the greater will be the comfort of the occupants. This state-
ment can be proved, although the gradually increasing sizes of wheels
and tires as used on the best cars, both here and abroad — advancing
from the early 26 and 28 X 3-inch tires, to as high as 38x5j-i n ch
tires, and freaks up to 48 X 12-inch — should be sufficiently convincing.

Advantages of Large Wheels. A graphical demonstration of the
difference between the action of the large and small wheel to the
advantage of the former is shown in two drawings, Figs. 487 and
488. Fig. 487 presents the case of wheels passing over a common brick
4 inches wide by 2 inches high, and Fig. 488 shows the action in
passing across a small rut in the surface of the road, 8 inches wide

284

Digitized by

Google

GASOLINE AUTOMOBILES 623

by 1J inched deep. In both cases, A shows the 28-inch wheel and B
shows the 40-inch wheel. Both instances, too, have been selected at
random, and not so chosen as to favor either wheel. It would have
been possible to so select the sizes of both obstruction and depression
as to make out a stronger case.

The height of the brick being 2 inches the wheel must rise that
distance, whatever its diameter, but in the case of the 28-inch wheel,
this rise of 2 inches is largely relative to the wheel diameter being
one-fourteenth, or 7 per cent. In the case of the larger wheel of
40-inch diameter, the rise is again 2 inches, but it is now one-
twentieth of the wheel diameter, or 5 per cent. In the case of the

Fig. 487. Diagram Showing Advantage of Large Wheels in Passing over Obstruction

smaller wheel, the rise is distributed over a length of about 18.43
inches from the moment when the forward edge strikes the
obstacle to the moment when the last part of the tire leaves the
last edge of the brick. If this rise were evenly distributed over
this distance, rising as an arc of a circle, its radius would be slightly
over 22 inches.

Considering the 40-inch wheel under the same circumstances, it
performs the act of rising and falling 2 inches in the longer distance
of about 21.5 inches, the radius of this rise being 38.75 inches. It is
obvious that the latter is a much easier rise than the former, the
lift being distributed over a length 16 per cent greater. Similarly,
with the descent from the high point to the surface of the road again,

285

Digitized by,

Google

624 GASOLINE AUTOMOBILES

this more gradual rise and fall convert the surmounting of the
obstacle from a sharp upward bump and downward jounce into an
easy and not unpleasant swinging up and down.

A drop into a hole, as illustrated by Fig. 488, shows the bene-
ficial effect of the large wheel better, perhaps, than does the rolling
over a rise. A rut in the road 8 inches across, into which the two
wheels drop in passing, is shown. At A, the 28-inch wheel is seen to
drop the considerable amount of ^ inch, while at B the 40-inch
wheel drops but f inch into the same hole. Evidently the larger
wheel has an advantage in so far as passing over obstacles or holes
is concerned.

Again, on account of its larger radius, the arc of the larger
wheel is flatter and has more length of tread in contact with the

Fig. 488. Diagram Showing Advantage of Large Wheela in Passing over Depression

surface of the ground, this being particularly noticeable on rough
roads. Not alone does this mean added adhesion to the ground and
thus lessening driving effort to propel the same car, but it also means
a greater resistance to side slip or skidding, thus conserving the
power and increasing the safety of the occupants. Other arguments
could be offered in favor of large tires for easy riding, but those
given should suffice.

PLEASURE-CAR WHEELS

Wood Wheels. Wood wheels are the most common form for
pleasure cars in this country, being almost universal. Ordinarily,
they are constructed of an even number of spokes, which are tapered
at the hub end and rounded up to a small circular end with a shoulder
at the rim, or felloe, end. Fig. 489 shows this construction, A being

286

Digitized by

Google

GASOLINE AUTOMOBILES

625

Fig. 489. Construction of Wood Wheels

the felloe on which is the rim B, and R is the spoke which, at the hub
end, tapers down to the wedge-shaped portion P. This matches up
to the wedge-shaped ends of the other spokes, so that when the
wheel is assembled they form a continuous rim around the central
or hub hole.

The spokes are held at
their inner ends by metal
plates and by through bolts,
which are set at the joints
between the spokes so as to
pass equally through each
spoke, as shown at D. Not
only do these bolts hold the
spokes firmly to the wheel,
but they have an expand-
ing, or wedging, action
tending to make the center of
the wheel very rigid.

The outer end of the spoke has a shoulder E and a round part C,
which fits into a hole bored through the felloe. To prevent the
felloe coming off after the spoke is in place, the spoke is expanded
by means of a small wedge driven into it from the outside, as shown
at F. In this way, the wheel is
constructed from a series of com-
ponents into a strong rigid unit.

Such wheels wear in two
places, at the inner and at the
outer ends of the spokes. The
remedy in the latter case is to
withdraw the small wedge and
insert a larger one in its place.
At the hub end, when wear occurs,
this, too, must be taken up by p^. 490 .
means of wedges. Fig. 490 shows
a method of doing this when
joints. A false steel hub A is

Method of Tightening Spokes
of Wood Wheels

the hub has no bolts at the
driven into the hub hole, after
which wedges of steel are driven in between the wedge-shaped ends
of the spokes. For slight cases of wear and squeaks, the wheel may

287

Digitized by

Google

626

GASOLINE AUTOMOBILES

be soaked in water, which will cause it to swell, taking up all of
the space.

There are various modifications of this, nearly all of them
changing the hub end of the spoke. In the Schwartz wheel, a patented
fprm, each spoke is made with a tongue on one side of the wedge-
shaped part and a groove on the other. In assembling the wheel,
the tongue of each spoke fits into the groove of the spoke next to
it, thus rendering the whole hub end of the wheel, when assembled,
a stronger unit, being stronger in two directions, one of them of
more than ordinary value. In driving the tongue into the groove,
the wheel is rendered strong in a radial direction, but, when the wheel

Fig. 491. Details of Wood Wheels with Staggard Spokes

is entirely assembled, the tongue-and-groove method leaves it very
strong to resist side shocks, a point in which the wood wheel is weakest.
Staggered Spokes. As mentioned above, the wood wheel has
little lateral strength, nor can it ever have, from the very nature of
its construction, except in unusual cases, like the Schwartz patent
wheel just described. A method of increasing the lateral strength
somewhat is that of using staggered spokes, these being alternately
curved to the outside and to the inside, as shown in Fig. 491. This
gives one set of half the spokes forming a very flat cone with its
apex, or point, at the inner side of the hub, while the others form
another cone with its apex at the outside of the hub. Each one of

288

Digitized by

Google

GASOLINE AUTOMOBILES

627

these conical shapes is stronger to resist stresses from the side on
which the point is located than would be the same number of spokes
set flat. Hence, the staggered-spoke wheel has the advantage over
the ordinary type in that it has greater strength from both sides.
In the figure, A is the iron hub, B the felloe, Ci the right-hand and
C* the left-hand spoke, and D the steel rim for the tire. This is a
12-spoke wheel, 6 of the right-hand spokes C\ and 6 of the left-hand
spokes C 2 . The section shows how these pass alternately to the one
side or to the other, forming the strong cone shape.

Fig. 492. Section of Steel
and Wood Wheel

Fig. 493. Complete Steel and Wood
Truck Wheel

Another method of handling this problem in a somewhat similar
manner is the use of double sets of spokes, the spokes, however, being
in two different planes separated a considerable distance at the hub.
Of a necessity using the same felloe, the outer ends must be in the
same plane. Fig. 492 shows a drawing representing a section through
the center line of the wheel, while Fig. 493 shows a photographic
reproduction of it.

In Figs. 492 and 493, A represents the steel rim on the felloe
F 9 the latter being of metal in this case, as is also the wheel so it

289

Digitized by

Google

628

GASOLINE AUTOMOBILES

may be disassembled. The spokes R have a tubular end piece of metal
G, which is set over the rounded end of each spoke and fits into a
hole in the felloe. / and S are, respectively, the inner and outer
parts of the hub, which are held together and to the spokes by means
of the bolts N. Z is the hub cap, while U and V are filler pieces
aiding in the dismantling process. The strength of the wheel is self-
evident, but it is difficult to see the advantage of the disassembling
feature, as a stress or strain which would break one spoke, would, in
almost every case, break practically all of the spokes, thus neces-
sitating a new wheel instead of new spokes.

Wire Wheels. Many of the little details of- the automobile
were inherited from its predecessor, the bicycle. Among these may
be mentioned the wire wheel. Practically all bicycfe wheels were

and are of the wire-spoked type,
and this same form of wheel was

Qused on all earlier automobiles.
It had no strength in a sidewise
direction, nor did it, in fact, have
much of anything to recommend
it except its light weight. For
this reason, it failed in automobile
service, and received a setback
from which it has even now not
wholly recovered.
Early Bicycle Models. Fig. 494 shows an early type of wire
wheel for automobiles, its construction indicating clearly its bicycle
ancestry. The spokes were set into a casting, which formed the hub,
and into the steel rim by means of a threaded sleeve, the head on
each end of the spoke resting on the inner end of the sleeve. The
sleeves were screwed in and out to adjust the tension of the spokes.
This tension was usually considerable, thus reducing in part the
ability of the wheel as a whole to resist side stresses, for the piece
already in tension could not be expected to sustain additional ten-
sion, or compression, or a combination of either with torsion, accord-
ing to the way the force was applied. Then, too, the casting for
the hub was wholly unsuited to resist stresses, and the distance apart
of the spokes at the hub was not sufficient, making the cone so very
flat that it had very little more strength than a perfectly flat wheel.

Fig. 494. Hub Details of Bicycle Wheel

290

Digitized by

Google

GASOLINE AUTOMOBILES

629

Following the failure of wire wheels, ther6 was a rapid change
to wood wheels, which were almost universal for several years.
Soon after this change was made, there was an increase in the size
and power of automobiles, which, in turn, was followed by a demand
for lessened weights. In the meantime, makers of wire wheels,
knowing their faults, began to re-design in order to eliminate them.
Their success is best evidenced abroad, where about one-half of the
French and more than two-
thirds of the English cars,
in addition to over seven-
eights of the racing cars
in both countries, are now
equipped with wire wheels.

New Successful
Designs, This result has
been brought about by a
realization of the previous
defects and their elimina-
tion. Thus, no more cast
hubs are used, drawn or
pressed steel of the highest
quality and greatest
strength being used instead.
The spokes have been car-
ried out farther apart at
the hub, obtaining a higher
cone and thus a stronger
one. Spoke materials are
better and stronger, besides being used in greater quantities, that
is, larger spokes and larger numbers of spokes per wheel, in some
cases a triple row of spokes being used in addition to the ordinary
two rows. This additional row acts as a strengthener and stiffener
much like the diagonal stays on a bridge. Fig. 495 shows a set of
double-spoke wire, triple-spoke wire, and interchangeable wood
wheels side by side for comparison, while in Fig. 496 is presented
a recent triple-spoke front wheel in detail.

In the former figure, the relative depths of the various cones
and their corresponding strengths are made evident, beinc; side by

Fig. 495.

Sections of Double and Triple Steel and
Wood Spoke Wheels

291

Digitized by

Google

630 GASOLINE AUTOMOBILES

side. In this comparison, it will be noted that the new triple-spoke
wheel has a much longer outer cone than the double-spoke wheel,
while, on the other hand, the inner cone has been flattened. The
triple spoke has a greater depth, considering the set of them as an
additional cone, than has the inner cone in the double-set wheels.
In examining closely the older double-spoke form and the newer
triple type, it will be noted, also, how the
wheel itself, or rather the tire and rim,
have been brought closer in to the point of
attachment, thus rendering the whole con-
struction stronger and safer. In Fig. 495,
it will be seen that the center line of
both tire and rim passes midway between
the inner and outer ends of the hub on
double-spoke wheels, while on the triple
form it is even with the inside end of the
inner hub, being, in fact, farther in than
is the case with the wood wheel. One
thing will be noted in all these spokes,
regardless of number, position, or inclina-
tion, and that is that their ends present a
straight head. On the older bicycle spokes,
the diagonal-spoke head was a great source
of weakness, tending to create failure at
the outset. The modern wire wheel is so
constructed as to do away with this fault.
By actual tests, the wire spoke — not the
stronger triple spoke but the double spoke —
has been found to have the following
advantages: lighter weight for the same
n«. 496. Details of Triple-Spoke carrying capacity; greater carrying capac-
Front wheel ^ £ or ^^j weight ; superior strength from

above or below in the plane of the wheel ; lowerfirst cost (it is doubtful if
this will hold good for the newer triple-spoke forms) ; and, in addition,
tests have proved superior strength in a direction at right angles to
the plane of the wheel. So marked is the difference in weight of the
two that five wire wheels are said to be lighter in weight than four
wood wheels of equal carrying capacity.

292

Digitized by

Google

GASOLINE AUTOMOBILES

631

All these arguments in favor of wire have been built up one by
one, for much prejudice had to be removed. In spite of this, however,
the wheel is slowly but surely building up a reputation and a long
list of friends. Since, even now, England and the Continent continue
to set the fashion in automobiles, it is not too much to expect to
see wire-spoke wheels in common use in the United States in a few
years. In fact, the dozen manufacturers
offering this wheel in 1914, with ten more
giving it as an option, have been increased
to about forty who are fitting it regularly,
with perhaps fifty or more offering it as an
option in 1915. In fact, almost any 'car
maker in the country will fit wire wheels
for a slight additional charge.

For 1917 some 20 odd makes of cars
are offered with wire wheels as 'regular
equipment, and about 25 more offer this
as an option without extra charge. As
there are about 190 cars on the market,
the former represents 10.5 per cent, and
the latter 13.2 per cent of all makes; the
two together total 23.7 per cent, or less
than one-quarter. However, these figures
do not quite indicate the relative popu-
larity of wire wheels.

Wire Wheels Much ' Stronger. , The
increase in the use of wire wheels has
been brought about by better designs;
greater attention to the details of manu-
facture, assembly, and use; but primarily
by the greater strength which has been
built into the wire wheel. One way in
which this has been done is by rearrange-
ment of the spokes as, for instance, the triple-spoke form just
described and shown in Fig. 469. Another and later form is the
quadruple-spoke wheel as seen in Fig. 497. This is made and sold by
the General Rim Company, Cleveland, Ohio, and is called the G-R-C
wheel. As the sketch indicates, it has all the features of demount-

Fig. 497. G-R-C Quadruple
Spoke Wire wheel

293

Digitized by

Google

632 GASOLINE AUTOMOBILES

ability, etc., of other wire wheels, the notable differences being the
spoke arrangement to give strength and the form of rim — a patented
form to be described in detail later.

By comparison with Fig. 496, it will be noted that a double
triangular section is formed in the G-R-C, the inner spokes forming the
inside of the hub and the outside of the hub forming one triangle,
while the outer spokes from each form the other. In Fig. 496, it
will be noted that there is but the one triangle and a straight row
of spokes.

Sheet-Steel Wheels. The sheet-steel wheel is really a form of
wire-spoke wheel, with an infinite number of spokes joined together.
It has many advantages, some of which might be mentioned as
follows: strength, lightness, low first cost, low cost of maintenance,
and cleanliness. To take them up in order, the strength of two steel
plates set a few inches apart in a somewhat triangular form with
the base toward the hub and well attached at the center and at the rim
of the wheel, is self-evident. Aside from the natural strength of the
steel plates — far in excess of the wire spokes — or round wood spokes,
there is the strength of the triangular form. A strong connection at
the top and at the bottom makes the whole construction very similar
to a structural form. This shape closely resembles a box girde^,
having great resisting strength in all directions.

The light weight of the steel wheel comes from the thinness of
the steel plates which are used, and similarly from the thin and light
connecting members, either top or bottom. In Fig. 498 the junction
at the top is seen to be nothing more than the steel rims for the tire,
thus doing away with the usual felloe or substitute for it. In this
figure, the wheel is seen to consist of the hub made with two flanges,
to which the side sheets are bolted; the brake drum I bolted to the
sheet on the inside, midway up its height; the steel rim mentioned
before; and the bolts and rivets necessary to join the parts. At
the hub, bolts are used to allow of dismounting the sheets in case of
damage, for replacement or otherwise. At the rim, however, the
plates are riveted to the rim, and riveted together.

Low first cost is brought about by the simplicity of the wheel.
The wheel consists of the usual rim, not counted in the wheel cost,
and two pressed-steel sheets flanged at the top, with a few holes
punched in them. These sheets are very cheap to make, while the

Digitized by VjOOQIC

GASOLINE AUTOMOBILES

633

hub construction is much cheaper than the ordinary hub, for the
reason that there are usually two parts where this construction
requires but one, and this a very simple one needing little machining.
Low maintenance cost is brought about by the rigidity of the whole
construction; the few parts, which make few to replace or even to
wear; the cheapness of these parts, when replacement is necessary;
and the well-known strength and long life of sheet-steel plates.

On the score of cleanliness, it may be said that this is one of
the drawbacks of the wire-spoke wheel, cleaning between and around

Fig. 498. Side and Sectional Views of Sheet-Steel Wheels

the spokes being very difficult, if not actually impossible. The
large number of spokes makes the hub inside of the spokes impossible
to clean, whereas, with the sheet-steel wheel, the cleaning consists
in merely turning a hose on the sides of the wheel, the cleaning of
the hub being entirely unnecessary.

It will be noted, too, in this illustration that the wheel has
considerable spring, or should have, in a vertical direction. It is
claimed for this type of wheel that this springiness is an added
advantage as it allows the use of solid or cushion tires, and thus

295

Digitized by

Google

634 GASOLINE AUTOMOBILES

eliminates the troublesome pneumatic tire with its puncture and
blowout possibilities. For commercial-car use, all of the advantages
just mentioned are of double worth, for which reason the steel wheel
is making great strides forward on commercial cars. Where the
springiness of the wheels is not so desirable as strength, the sheet-
steel plates may be replaced with either pressed- or cast-steel side
members on which strengthening ribs are formed. The sides of the
wheel have holes HH through them which are provided for ventila-
tion, to decrease the weight of the side sheets, and to lessen the wind
resistance to the wheel when moving rapidly. In some steel wheels
these holes are omitted; in others a larger number than the four

shown here are used. Fig.
499 gives a better idea of
the general appearance of the
wheel ready to use, being
lettered the same as Fig. 498.
The spokes shown in Fig. 499
are painted on the smooth
exterior of the plates, but in
other wheels these spokes are
formed in the plates as pre-
viously mentioned.

Steel Wheels Designed for
Cushion Tires. Sheet-steel
wheels, particularly those of
very thin sheets, have a cer-
tain amount of springiness,
this being utilized with solid
and cushion tires on the

Fig. 499. Sheet-Steel Wheel Complete assumption that the wheel

will absorb the vibrations set up by the road inequalities. In Figs,
500 and 501, a wheel is shown which was designed for this express
purpose. The wheel is called an elastic wheel and uses solid tires.

By means of the figures the construction is made clear, the wheel
consisting of two halves, one a single sheet of metal attached to the
hub and forming its own rim portion, and the other a section which
consists of two sheets, one attached to the hub and forming its own
rim portion, with another additional plate riveted to it near its outer

Digitized by VjOOQlC

GASOLINE AUTOMOBILES

635

end and attached to a middle flange on the hub. The two outer
members of themselves would be very springy and consequently
very weak, being of very thin metal. The diagonal extra sheet stiffens
the whole construction, besides adding 50 per cent to its side strength.
This is also of thin metal, so the whole wheel retains some springiness.
Parker Pressed-Steel Wheels. One fault with all the steel and
sheet-steel wheels mentioned was that they did not resemble other
wheels, consequently the people did not want them. Moreover, in
many cases, their construction did not adapt them to the
use of regular tires but, on the contrary, called for special
and expensive forms. However, none of these drawbacks
are present in a new form of pressed-steel wheel, Fig. 502.
Upon close inspection it will be seen that this wheel has
no felloe in the ordinary sense, the rim of the wheel form-
ing the only felloe. In this respect, the wheel is an
outgrowth of the former Healy demountable rim, the

Fig. 500. Sted

Wheel Fig. 501. Disassembled Steel Wheel

modern form being a combination of a demountable rim with steel
spokes. This wheel is suitable for any car, the hollow steel spokes hav-
ing great sustaining power. It is interchangeable with all ordinary
wood artillery wheels of the same size, and fits between the usual hub
flanges. The spoke portion is made as a pair of units, each forming
half of all the spokes, the two being welded together. When finished
in this manner, they have half the weight and more than twice the
strength of the wood wheel, the greatest saving being at the rim,
by the removal of from 60 to 100 pounds of metal and wood*

This wheel takes the ordinary demountable rim directly upon
the ends of the spokes, the one shown being the No. 2, which is suit-

297

Digitized by

Google

636 GASOLINE AUTOMOBILES

able for about twelve different rims as made by the largest manu-
facturers. The No. 1, whose only difference in appearance is a flat
spot just under the bolt heads at the ends of the spokes, takes all one-
piece clincher or straight side rims, whether clincher or Q.D. (quick
detachable). The wheel shown is a 36- by 4|-inch size, made from
.083-inch sheet steel, with ten spokes If inches round and a center
portion, all of the same thickness of steel.

A number of other pressed-steel wheels, made, like the Parker,
by pressing out two or more simple units, and welding these together,

are making their appear-
ance. These show great
ingenuity and variety in
the methods used to pro-
duce this same result and
yet avoid the Parker
patents. This form of
wheel, having the appear-
ance of wood, yet with
greater strength and
dependability and also of
lighter weight, may per-
haps be the final answer
to the wheel problem;
certainly this is possible

Fig. 502. General Appearance of Parker Hydraulic if quantity production

oteel Wneel 9

can bring them down
below the price of wood wheels, which now seems apparent.

COMMERCIAL-CAR WHEELS

Requisites. On commercial cars the service is so different as
to call for entirely different wheels. Of course, many commercial-
car wheels are nothing but pleasure-car wheels with heavier parts
throughout, but it is coming to be recognized that heavy trucks,
tractors, and similar vehicles should have their wheels designed for
the service required of them the same as lighter cars. No springiness
or resiliency is required for heavy truck service, but simply these
three things: strength to carry load and overloads; strength to
resist side stresses; and such material, design, and construction a§

Digitized by LiOOQ IC

GASOLINE AUTOMOBILES 637

will make for low first cost and low cost of maintenance. A fourth
desirable quality might be added to these, the quality of being
adaptable or adapted to the tires to be used.

Wood Wheels. Taking Fig. 503 as an ordinary heavy vehicle
wheel, let us see in what ways it fulfills or falls short of these require-
ments. The spokes are large in both directions and widened out at
the felloe to give greater side
strength. The felloe, which
cannot be seen, may be judged
as to size from the width and
location of the dual tires,
which would indicate great
width and considerable thick-
ness. This style of tire calls for
a steel band shrunk over the
felloe, while the heads of the
cross-bolts show how the tires
were put on and held on.
All these make for great
strength in both horizontal
and vertical directions, and
all parts except the spokes
are simple to make, and even
these are simple for the wheel
manufacturer whose shop is
rigged to make them . More-
over, tO fill the last require- Fig **' DoubMir. Wood I*u* WM

ment, the wheel is adaptable to this tire or to any one of a number of
motor-truck tires which might be used.

A slight variation from this is the double-spoke wheel, in which
the spokes, in additioh to being placed in double rows, are set so
as to miss each other across the wheel, that is, each spoke of one
row coming between two of the other. This placing allows the spokes
to be made larger and stronger than in the ordinary case, while the
double rows have the same strengthening effect as the tapering of
spokes. The hub portion is assembled as two separate wheels, so
that the work of assembling as well as of making the parts is slightly
more than with the ordinary wheel. This is more than compensated

299

Digitized by

Google

638 GASOLINE AUTOMOBILES

for by the added strength. It is but fair to state that each of the
last two wheels described is of English make.

In all wood wheels, the blocks composing the wheel and tire
are of well-seasoned rock elm, sawed into wedge-shaped blocks, with
the fiber lengthwise. The blocks are glued and nailed together
until they form a circle. They are then turned round and to size
in a large wood lathe, a shoulder J inch wide being formed at the
same time on each side of the tire 2.5 inches from the tire surface.
A heavy steel ring with a corresponding shoulder is then shrunk

Fig. 504. White Cast-Steel Wheel

over the wood shoulder on each side of the tire, drawing it together
much like the ordinary steel tire on a wood wheel of a carriage.
Bolts are run through these rings and through the wood blocks from
side to side to prevent the blocks from splitting sidewise. To increase
the life of this tire, steel wedges J inch thick are driven crosswise
into the face of it 2.5 inches deep around the whole tire about 3
inches apart. These wedges prevent the tire from slipping; in fact,
they act like an anti-skid chain and do not harm the pavement,
being set flush with the surface of the wood blocks.

300

Digitized by VjOOQlC

GASOLINE AUTOMOBILES 639

It is said that one set of these tires was used for nine months,
and at the end of that time they were still good for service. The
tires reach clear to the hub, thus doing away with spokes and enabling
the tires to be slipped over the hub and held in place by a removable
flange bolted through the wood to the fixed flange on the opposite
side of the hub.

Cast-Steel Wheels, The heavier the service the more unsuit-
able do wood wheels become, that is, wood-spoke wheels. For many
five-ton trucks, practically all seven- and ten-ton trucks, and nearly
all tractors, the cast-steel wheel is used, either spoked or solid, the
spoked form being given the preference. Fig. 504 illustrates a spoked
cast-steel wheel, fitted with a solid tire. The wheel is cast with ten
heavy ribbed spokes, a ribbed felloe, and a grooved-felloe surface,
into which the tire is set.

Miscellaneous Wheel Types. Steel. Steel wheels are gaining
for heavy truck use, and a number of the better steel-casting firms
are now getting into this work, with the result that better steel
wheels are becoming available.

Other constructions, such as steel and wood combination wheels
with removable and replaceable spokes, and the like, are rapidly
going out of existence. Truck work is unusually severe, and it takes
but a few weeks of actual use to show up any of the so-called freak
wheels. The simplest seems to be the* best, the only question at
present being whether the material shall be wood or cast steel.
Pressed steel may offer some opportunities in combination with
welding, since good work has been done on pleasure-car wheels of
this type.

Spring Wheels with Longitudinal and Tangential Springs. Spring
wheels for both pleasure cars and trucks have not proved to be all
that was claimed for them. ' For pleasure-car use they have gone
out entirely; for truck use they are restricted to the smaller and
lighter sizes, as the 1£- and 2-ton sizes driven at high speeds in city
work. On these sizes, one or two well-designed forms are giving
good service. The cherished dream of putting the pneumatic tire
out of business through the medium of the spring wheel is still a dream.

When longitudinal springs are used to do away with the alter-
nations of stresses peculiar to the radially disposed springs, the
appearance of the wheel is much altered, as Fig. 505 shows. This

301

Digitized by VjOOQlC

(>\0 GASOLINE AUTOMOBILES

wheel consists of an inner wheel, having its own spokes — ten in
number — and its own felloe. To the felloe are attached by means
of bolts V-shaped arms, which hold one end of a series of spiral springs,
the other end of each of the springs being held in a similar V-shaped
arm bolted to the opposite side of the outer felloe carrying the tire.
There are eighteen of these springs in two sets of nine each. Those
springs which have their near end fastened to the near side of the
inner felloe have the far end fastened to the far side of the outer

Fig. 505. Seaton (American) Spring Wheel

felloe, while those attached to the far side of the inner felloe have
the other point of attachment on the near side of the outer felloe.
When the wheel strikes an obstacle, a twisting action is set up,
the outer felloe and tire moving while the inner felloe and axle remain
stationary. This twisting of the springs tends to coQ them tighter,
which results, when the obstacle is passed, in the springs untwisting
and turning the outer felloe and tire backward as far as it was previ-

Digitized by VjOOQIC

GASOLINE AUTOMOBILES

641

ously moved forward. Since, however, the springs have a certain
amount of stiffness in their coils, and the wheels do not rise and fall
relative to one another, except in so far as the twisting action is
concerned, it follows that considerable shock must be transmitted
to the axle and thus to the body and its occupants. This wheel,
therefore, while possessing strength to resist side stresses, does not
give the smooth riding qualities so much desired.

A wheel very similar in appearance and action but with the
wood spokes eliminated has been used very extensively in the last
few years by the express companies and other big users of motor
trucks. Starting with a few of them on front wheels, they have
saved tires and tire money
to such an extent that
the companies have added
more and more. Next they
were tried on rear wheels.
Seeing the good results
obtained by the big com-
panies with these wheels,
many smaller firms and
tradesmen with only one
or two trucks have adopted
them. They take a small size
solid tire in place of a very
large pneumatic and are said
to cut the tire cost from one-
half up to two-thirds and more. While used mainly for vehicles carry-
ing a 1-ton load, they have been tried successfully on 2-ton vehicles.

It is in this class of service — the lighter vehicles for smaller firms
— where every item of expense must be watched very carefully that
the resilient wheel should show the best results. For heavy work,
there seems little future for it.

A form of wheel which comes somewhere between the two just
mentioned, having some side strength and easy-riding qualities, while
at the same time participating in part of the principles of both those
described, is that shown in Fig. 506, which is a diagram showing the
construction. This consists of spiral springs used not radially nor
longitudinally, but tangentially. Moreover, the springs are not

Fig. 506. Diagram of Action of Taylor Spring Wheel

303

Digitized by

Google

642 GASOLINE AUTOMOBILES

attached directly to the hub, but to levers pivoted on an outer, or
false, hub. When an obstruction is met with, so that the tension of
the springs is altered, the springs act upon the levers and thus turn
the false hub about the real inner hub by an amount corresponding
to the character of the obstruction. This eccentric motion of the
outer hub, induced by the spring action, takes up the shock of
the road obstruction much as does the wheel shown in Fig. 505.

The construction is such as to allow of the springs being covered
by means of a water-tight case, which will protect them from the
elements and thus lengthen their life. This is a good feature which
is lacking in all other wheels thus far shown.

Spring Wheels with Flat Spiral Springs. The flat spring bent
into a semicircular or spiral form is little used for spring wheels.
There is a double reason for this; they lack every desired quality,
unless it be side strength. If stiff enough to handle considerable
load, they are heavy, they are slow acting, and their action is long
continued; if made light, they act too much and the vibrations are
long drawn out. Moreover, if few springs are used, the breaking
of a single one puts the wheel out of use; if many are used, the wheel
becomes very heavy.

While a number of flat-steel spring wheels have been constructed
both here and abroad, they have not been uniformly successful, as has
been pointed out. A French form which was widely tried a few years
ago had a pair of sets, each of six springs, with a long curving shape,
one end attached to the hub and the other to the rim, while the leaves
on the two sides were set in opposite directions. The idea was that
loading would produce an eccentric movement of the rim relative
to the hub, and that the opposing of the two sets of leaves would
produce an absorption, one side absorbing the tendency to movement
of the other. In practice, however, this idea did not work out, as it
gave a noisy, hard-riding wheel, with a tendency for the springs to
break. These disadvantages, added to its weight, put a stop to its use.

An American device, constructed along somewhat similar lines,
but with all springs pointed in one direction, had only a limited use
in the home town of the inventor and is not now used.

Modern Status of Spring Wheel. The more modern view is not
that the solid tire will be eliminated, but that a form of steel-spring
or other resilient wheel will be produced which will have all the advan-

304

GASOLINE AUTOMOBILES 643

tages of wood and, in addition, will so save the solid rubber tires that
mileages twice as great will be obtained. In this way, the tire cost
will be cut in half, which will be sufficient within the ten-year life of
the ordinary commercial car to warrant the purchase of the more
expensive wheels.

In the use of spring wheels, as well as of wire wheels for pleasure
cars, the tire and rim situations are closely inter-woven. No special
form of wheel or rim can be successful which calls for a special tire in
addition, because, in case of trouble on the road, in a small town, or
anywhere outside of the big cities with large and varied sources of
supply, the users would not be able to replace the tire. As will be
pointed out later, the present rim-and-felloe situation, which might be
described as chaotic, must necessarily continue until the tire situation
is cleared up. That done — and it is now in a fair way of being done
soon — the rim situation also will be quickly cleared up, and, following,
that of the wheel felloes. The natural fitness of the various forms and
the unfitness of others to meet popular demand is rapidly clearing the
way for the engineers and manufacturers who are attempting this
standardization work.

WHEEL TROUBLES AND REPAIRS

The removal and handling of wheels present probably the
biggest problems in connection with them. True, broken wheels
give the repair man a good deal to think about, but the quick accu-
rate handling of jobs in which a broken wheel figures depends more
upon possessing and knowing how to use certain equipment than
anything else; the operations are so simple that they require no
particular skill or knowledge.

Wheel Pullers. In handling wheels a wheel puller of some form
is generally a necessity; wheels are removed so seldom that they are
likely to stick, and they get so much water and road dirt that there
is good reason for expecting them to stick or to be rusted on. This
means the application of force to remove the wheel. For this purpose,
a wheel puller is needed, and a number of these have been illustrated
and described previously, as gear pullers, steering-wheel pullers,
etc. Any one of these devices which is large enough to grasp the spokes
of the wheel and pull the latter outward and, at the same time, press
firmly against the protruding axle shaft will do the work well.

305

Google

644

GASOLINE AUTOMOBILES

Sometimes, however, while owning a puller, a wheel breaks
down on the road where this is not available, or the repair man is
called without being told the trouble, so that he does not bring the

puller with him. In such cases,
the repair man must improvise
some kind of a puller out of what
he has on hand. Everyone carries
a jack, so it is safe to assume that
one of these w r ill be available as
well as some form of chain. If a
chain of large size is not available,
tire chains — particularly extra
cross-links; — may be fastened to-
gether to answer the purpose. If
chain is lacking, strong wire, wire
cable, or, in a pinch, stout rope
can be substituted. Attach the
rope, wire, or chain to a pair of
opposite spokes of the wheel,
Fig. 507, allowing usually about two feet of slack. Draw the chain
out as tightly as possible, place the jack with its base against the
end of the axle and work the head out by means of the lever until it

^ comes against the chain.

Fig. 607.

Makeshift Wheel Puller for Road
Repair Work

d Tr-vc h Wh—l3

^£ Truck Wh+ml*->*

Then by continued but
careful working of the
jack, the wheel is pulled
off the axle.

If rope, wire, or wire
cable is used, it is advis-
able to place a heavy
piece of cloth, burlap, cr
something similar over the
head of the jack to pre-
vent its edges cutting
through this material.
With rope only enough slack must be used to allow the jack in its
lowest position to be forced under it; this must be done because there
is so much stretch to the rope itself and so little movement in

Fig. 608.

Tire Platform or "Dolly"
Truck Wheels

for Handling

306

Digitized by

Google

GASOLINE AUTOMOBILES 645

the ordinary jack, that the combination of rope and jack does not
always work to advantage.

Similarly, the handling of heavy truck wheels gives much
trouble even in the garage, for they are so big, heavy, and
bulky that ordinarily two men are needed. One man can do
the trick, however, with a platform or "dolly" like that shown
in Fig. 508. This consists of a platform about 4 feet long by
25 inches wide, fitted with casters at the four corners. Inside of the
central part are placed a pair of wedges, one of which can be moved in
or out by means of a crank handle. To use this, the wheel is jacked up
a little over 2 inches, and the truck pushed under. Then the movable
wedge is forced in against the tire so that the two wedges hold the
wheel firmly and carry all of its weight. Then the casters are turned
at right angles so that the platform and the wheel may be moved off
together. The truck wheel is removed in the usual manner, that is,
with the aid of the wheel puller or such other means as the garage
equipment affords. The dolly also forms a convenient means of
handling the wheel when it is put back on its axle.

TIRES
Kinds of Tires. Broadly, there are three general classes of tires:
the solid, the pneumatic, and the combination or cushion. The solid
tire needs little comment or discussion here — being solely for com-
mercial cars — except in so far as it is used with some form of spring
wheel, hub, or rim, as just described. Similarly, the cushion tire is
mostly used for electric cars, its use following that of the solid tire.

PNEUMATIC TIRES

The pneumatic tire was originally developed for bicycle use and
in the beginning many single-tube tires were used. All of the tires
used today have two parts — an inner and an outer tube.

Classification. Considering only the double-tube types, there-
fore, the pneumatic tire may be divided into three kinds: the Dunlop;
the clincher; and various later forms brought out to go with the detach-
able demountable rims; and similar devices. These latter vary
widely in themselves, but all are modifications of the clincher form,
with minor differences of the difference in rims.

Dunlop. The Dunlop tire, so named after the Irish physician
who invented and constructed the first pneumatic tire, is brought

307

Digitized by

Google

646 GASOLINE AUTOMOBILES

down to meet the rim in two straight portions, perfectly plain and of
even thickness, that is to say, the tire has no bead, as it is now
called. The tire fabric is brought down to a straight edge at the rim,
as well as the rubber covering, as shown in Fig. 509. A is the steel
rim of the wheel, B the inner tube, C the outer shoe, which at the
rim or inner portion is brought down to the two straight parts DD.
This tire, like all of the early tires, had to be put on over the
edge of the rim by sheer strength, coupled with the flexibility of
the tire when not inflated. This was a hard task, and, moreover,
as soon as the tire was punctured or otherwise deflated, there was
a strong possibility of its being thrown off, and possibly lost, at
east after it had been stretched on and off the rim a few times.

Fig. 509. Section of Fig. 510. Section of Typical

Dunlop Tire Clincher Tire

Clincher. To prevent this latter happening, the clincher rim
and tire were brought out, each being dependent upon the other.
In the clincher tire, the fabric is brought down to the rim, and then,
instead of being left straight out as in the Dunlop, the material is
formed into a hump, or bead, which is shaped just like the hollow
formed in the rim. The latter differs from the usual Dunlop rim
only in having this deep depression to fit the bead of the tire. Fig.
510 shows this, in which the parts are lettered as before. In both
cases, the fabric of the tire is sketched in, and it may be noted that
the layers are fewer in number in the older form.

The great majority of tires now in use are of this type, although,
like the original Dunlop, it must be forced on and off the rim by
the stretch of the deflated tire, and by sheer strength, coupled in this
case with considerable natural ingenuity and some tools for lifting

Digitized by CjOOQ IC

GASOLINE AUTOMOBILES 647

the hard non-stretchable beading over the edge of the rim at one
point. This done, the rest is easy. For this purpose many tools
have been bought; some good, some bad, and some indifferent. After
a fashion, all do the work, but that tool is best which performs
the operation most easily, most quickly, and with the least damage to
the tire or rim. Fig. 511 shows a useful tool for this purpose.

The wire wheel and demountable rims, both allow quick road
changes of damaged tires, leaving the work of tire repair to be done
at home in the garage with proper heat, light, tools, and materials.
This is rapidly bringing back into use the lower price clincher and
straight-side tire forms, also many new tools have made their
removal or attachment a much easier and more simple task.

Demountable Rim Types. Following the development of the
clincher tire and rim until this form of tire was practically universal,
came the first forms of the
demountable rims, which
consisted of a detachable
edge or rim portion, like the
edge of the clincher rim in
section. These were locked
in place in various ways in
the different forms, but the
first demountable rims — they
were called detachable rims F * 51L ™***™**™

— were made by cutting the clincher rims into two parts, one of them
detachable. This allowed of slipping the tire on over the rim in a
sidewise direction, and did away with the stretching and pulling
necessary with the plain clincher. Since this was a tire which was
detachable more quickly than the ordinary tire, it was given the name
"Quick Detachable", and now both parts are known to the trade as
the Q.D. tire and rim.

Non-Skid Treads. All of the later developments in the clincher
tire have been along the line of studded or formed treads to prevent
skidding. In this many different things have been tried. Fig. 512
shows sections of many of the representative tires on the market.
They are well known, and only the last three need any comment.

Fig. 512 H shows the Kempshall (English) tire tread, which is
built up of a series of circular button-shaped depressions, or cups,

300

Digitized by

Google

648

GASOLINE AUTOMOBILES

which hold the pavement by means of the suction set up when they
are firmly rolled down upon it. This tire has been very successful
in England, but as yet has not been used much in this country.

The Dayton Airless tire, shown in Fig. 512 7, is a bridge-
constructed cushion tire in which the usual air space is given over
to a series of stiffening radial pieces of solid rubber, these with the
tread forming the bridge or truss. Fig. 512 J shows the Woodworth
adjustable tread for converting the usual smooth-tread tires of
whatever shape or form into non-skids. It is a leather and canvas

Fig. 512. Various Types of Non-Skid Tire Treads

built-up structure, shaped like the exterior of a tire, and freely
studded with steel rivets. When in place, the tire has all of the
appearance of a leather-tread tire with steel studs.

Proper Tire Inflation Pressures. With the recent great increase
in the value of rubber and the price of tires, the advice of manu-
facturers on the subject of tire wear is of great and growing impor-
tance. Nearly every manufacturer of tires is now recommending
a table of inflation pressures which agree among themselves more
or less closely. In each and every case, however, the makers are

310

Digitized by

Google

GASOLINE AUTOMOBILES 649

advising higher pressures than those generally used, stating that
the people do not pump their tires up hard enough to get the best
results from the materials in the tires. There should really be no
conflict of interests here as the owner should be as anxious to get his
mileage out of the tires as the makers are to make good their
guarantees.

Many makers have stated, as a result of their years of experience,
that more tires wholly or partially fail or wear out from under-
inflation than from any other one cause. It thus behooves the
owner of a car to look well to the pressure in his tires, not occasionally
but very frequently. As the majority of gages attached to pumps
in public garages are seriously in error, each motorist is advised to
purchase his own gage — one of the pocket type which is simple and
inexpensive — and carry it with him at all times.

In some cases, it will be found that pumping the tires up to the
makers' specified pressure will result in unusually hard riding, and
the motorist must be his own judge as to whether he wants to ride
more comfortably and get less wear out of his tires or to put up with
the discomfort and get every cent of wear out of them. In this
matter, very few will choose the latter course.

Use of Standard Pressure and Oversize Tires. There is really a
different way out. If the tire pressure advised by the maker results
in too hard riding for comfort while comfortable pressures result in
too much wear, the motorist is advised to get large size tires. These
on the same car will have a greater carrying capacity than the weight
of the car by a large margin. Just in the proportion of the tire
capacity to the weight of the car will be the pressure recommended
to the pressure utilized.

A simple example will make this clear: Suppose, for instance,
a car weighing 3850 pounds, equipped with 34- by 4-inch tires, for
which the makers claim a carrying capacity of 1100 pounds per wheel
and recommend a pressure of 95 pounds. If this pressure be too high
for comfort, and lower pressures, say 80 or 85 pounds, result in too
rapid wear, the. motorist should use larger tires. For instance, a
34- by 4J-inch tire is scheduled to carry 1300 pounds per tire, and the
pressure recommended is 100 pounds. The car weight per tire is
962 pounds, say 970. Changing to the larger tire gives a capacity
of 1300 pounds per wheel, while the load is actually but 970. This

311

Digitized by

Google

650 GASOLINE AUTOMOBILES

change provides a surplus capacity which can be utilized to increase
comfort.

Hence, if the tire be pumped up in the ratio of the carrying
capacity of the tires to the actual weight carried, the spirit of the
manufacturers' instructions will have been followed, comfort assured,
and long life of the tire attained as well. Here the ratio of the
capacity to the weight is as 1300 : 970. If now the pressure be figured
from this, using the 100 pounds recommended, a suitable pressure
will be obtained. Thus

1300 :970 : : 100 : x
x = 74.6 pounds
The pressure, therefore, in round numbers will be 75 pounds, and
if this or any comfortable pressure above this be used, only the
proper amount of tire wear will result, and a comfortable riding ca$
will be assured.

However, this proposition, namely, changing from 34- by 4-inch
to 34- by 4£-inch tires, is one which calls for entirely new rims, and
possibly entirely new wheels, or at least new felloes, because the bottom
diameter of the 34- by 4£-inch is different from that of the 34- by
4-inch. In such a case as this, the motorist would gain by changing
to a still larger size, say 35- by 4J-inch, which change can be made
without disturbing the old rims, as the 35- by 4£-inch is an oversize
for 34- by 4-inch. This size also is recommended to carry 1300
pounds at 100 pounds pressure per square inch, but maximum pleasure
and comfort will be obtained from it at between 72 and 80 pounds.

In general, the rule for oversize tires is this: Oversize tires are
1 inch larger in exterior diameter and £ inch greater in cross-section
than the regular sizes, and any tire so sized will fit interchangeably
with the regular size on the same rim. In general, too, the even-inch
sizes, as 30, 32, 34, etc., are considered as the regular sizes, while the
odd-inch sizes, as 31, 33, 35, etc., are considered as oversizes. The
above is for American or inch sizes only. The foreign, or millimeter,
tire and rim situation is in an even worse condition, and changes of
sizes are difficult in all cases and impossible in most.

Changing Tires. In the matter of changing tires, care must be
exercised in selecting the new tire of such a size as will fit the old
rim. A larger section of tire of the same nominal outside, or wheel,
diameter would call for a smaller rim diameter, meaning a change in

312

Digitized by VjOOQlC

GASOLINE AUTOMOBILES 651

rims and possibly wheels. A larger nominal outside diameter will
change the speed of the car and, if great, may be too much for the
engine, calling for new gearing as well. The following tabular
matter will be of interest, as it gives the changes in the metric
size tires which can be made without altering either wheel or rim
or changing the gearing.

Possible Tire Changes

760 mm. X 90 mm. wheels can be altered to 765 mm. X 105 mm.

810 mm. X 00 mm. wheels can be altered to 815 mm. X 105 mm.

and 820 mm. X 120 mm.

840 mm. X 90 mm. wheels can be altered to 850 mm. X 120 mm.

870 mm. X 90 mm. wheels can be altered to 875 mm. X 105 mm.

or 880 mm. X 120 mm.

910 mm. X 90 mm. wheels can be altered to 915 mm. X 105 mm.

or 920 mm. X 120 mm.

815 mm. X 105 mm. wheels can be altered to 820 mm. X 120 mm.

875 mm. X 105 mm. wheels can be altered to 880 mm. X 120 mm.

or 895 mm. X 135 mm.

915 mm. X 105 mm. wheels can be altered to 920 mm. X 120 mm.

or 935 mm. X 135 mm.

880 mm. X 120 mm. wheels can be altered to 895 mm. X 135 mm.

920 mm. X 120 mm. wheels can be altered to 935 mm. X 135 mm.

These can be used without changing the gearing or the wheels,
but to use different tires without changing rims is another matter.
It will, therefore, be necessary to have another table of the various
tires which are interchangeable on the same rim. Of the makes
which are fairly international in character may be mentioned the
German "Michelin" and the French "Continental". The following
Michelin tires may be fitted to the same rim, the two tires on the
same horizontal line being interchangeable in each case:

Interchangeable Michelin Tires

650 mm. X 65 mm. and 700 mm. X 75 mm.
700 mm. X 65 mm. and 750 mm. X 75 mm.
750 mm. X 65 mm. and 800 mm. X 75 mm.
800 mm. X 65 mm. and 850 mm. X 75 mm.
700 mm. X 85 mm. and 710 mm. X 90 mm.
750 mm. X 85 mm. and 760 mm. X 90 ram.
800 mm. X 85 mm. and 810 mm. X 90 mm.
860 mm. X 85 mm. and 870 mm. X 90 mm.

The following tires of the Continental make are interchangeable
on the same rims:

313

Digitized by

Google

652 GASOLINE AUTOMOBILES

Interchangeable Continental Tires

750 X 75 (motor cycle) and 750 X 80 (voiturette)
750 X 65 (motor cycle) and 750 X 65 (voiturette)
800 X 75 (motor cycle) and 800 X 75 (voiturette)
700 X 85 and 710 X 90 (light and heavy)
750 X 85 and 750 X 90 (light and heavy)
760 X 90 and 700 X 100 (light and heavy)
870 X 90 and 810 X 100 (light and heavy)
910 X 90 and 910 X 100
820 X 100 and 820 X 125
880 X 120 and 880 X 125
920 X 120 and 920 X 125
815 X 105 fit only 105 mm. rims

Note. Although the 105 mm. tire requires a special rim, a 90 or 100 mm.
cover can also be fitted on the same rim in the case of necessity.

810 X 90 or 810 X 100 fit on the 105 mm. rim

875 X 105 fit on the 105 tnm. rim

910 X 90 or 910 X 100 fit on the 100 mm. rim

895 X 135, 935 X 135, and 1000 X 150 require their own special rims

Speed Changes Due to Changed Tires. Before leaving the subject,
it might be well to say a few words concerning the change of speed
which a change in tire sizes will make in a vehicle, this in some cases
being so serious as to impair the utility of an engine formerly found
to be right in every particular. In the course of a very wide experi-
ence, the writer has found this to be the case with many old cars.
Using the old small wheels and tires, the engine was able to negotiate
all grades easily and make the required speed at all times. With
a change to larger wheels and tires, the car ran faster at all times
and gave much more trouble generally. It also proved a poor hill
climber, so much so, in fact, that the owner had to go one step further
and change the gearing so as to give the old speed ratios before the
engine again acted satisfactorily.

Recent Tire Improvements. There have been but three recent
notable improvements in tires which are briefly discussed.

Tire Valves. There have been several kinds of troubles with
the old form of tire valve. It was spring actuated, and the springs
were so small as to cause much trouble; further, it had to be screwed
in place, requiring a special tool. There are several new valve forms
with more than one seat, and others with an improved seat designed
to screw in with the fingers and to offer little or no resistance to
inflation.

314

Digitized by

Google

GASOLINE AUTOMOBILES 653

Inner Tubes. Improvement has been made in inner tubes
by the use of better and purer rubber in much thicker sections.
Some of these have a partial fabric reinforcement; others are made
and then turned inside out so that the tread portion is under com-
pression, thus resisting punctures or internal pressure. Other
designs present a tube larger than the inside of the tire before infla-
tion; this produces a truss formation of the rubber, which the air
pressure stiffens.

Cord Tires. The real improvement of value, however, is the
cord tire. One form of this is shown in partial section in Fig. 513.
This shows graphically that the difference between this tire and

Fig. 513. Section of Goodrich Silvertown Cord Tire, Showing Inner Construction

other forms is that the 4 to 6 or more layers of fabric have been
replaced by two layers of diagonally woven cord. This cord is
continuous, rubber impregnated, rubber covered, and, through its
size, allows a great and very even tension. Lessening the amount
and thickness of the fabric has given a greater percentage of rubber
in the tire; consequently, the cord tire is more resilient. The advan-
tages claimed for it are: less power used in tire friction, which meftns
more power available for speed and hill climbing; greater carrying
capacity in same size; saving of fuel; greater mileage per gallon of
fuel; additional speed; quicker starting; easier steering, thus less
driving fatigue; greater coasting ability; increased strength; and
practical immunity from stone bruises owing to superior resiliency.

315

Digitized by

Google

654 GASOLINE AUTOMOBILES

RIMS

Kinds of Rims. Nearly all rims are of steel or iron, but vary
greatly as to types. The writer has therefore chosen only a few
of the well-known ones, no preference being shown in this.

Rims will be taken up in the order of their development. Natu-
rally, the first rims were of the plain type, while the latest are of the
demountable, remountable, or removable types, all these being very
much the same. Between the two came the clincher rim, which is
properly a plain rim; and the quick-detachable rim.

Plain Rims. The form of rim first used was naturally the solid
type, shown with the Dunlop tire in Fig. 509. This form is a simple
endless band with two edges just high enough to prevent the tire
from coming off sidewise when it has once been stretched in place.
Nothing like it is used today, the nearest approach being the form
of rim used with single-tube bicycle tires.

Clincher Rims. Clincher rims were brought out primarily to
avoid the weaknesses of the Dunlop, viz, a weakness at the base,
and, hence, it had an unusually heavy bead. Another fault which
this tire remedied was the tendency under high pressure for the tire
to draw away from the rim. This was avoided by the edge of the
clincher being made fairly wide where it was designed to go into
the pocket, or groove, formed by the contour of the rim.

It is the depth of this pocket, or groove, and the corresponding
size of the edge of the bead on the tire, both excellent qualities, which
make the tire hard to put on and take off. This may be seen from
the previous illustrations of clincher tires, notably Fig. 510.

Quick-Detachable Tire Rims. It was this inherent difficulty
of handling the clincher tire and rim which brought about the quick-
detachable tire. This did not differ from the clincher tire in the
tire portion, the difference being in the rim, which has one curved
portion made in removable form, with a locking ring outside of it or
made integral with it. In some quick detachables, the rim is expanded
by a special tool and a spacing piece set into place, which holds the
edge expanded. When this is done, the ring — as it is a simple ring
with special ends — is held in place until released by the use of the
special tool. On the end of the ring there are two little square lugs
which project downward and have a hook shape. The one edge of
the rim, made flat and straight on that side, has a slot with stag-

316

Digitized by

Google

GASOLINE AUTOMOBILES 655

gered, rectangular ends into which these lugs fit. It requires force
to spring the rings together so the lugs will go into the slots, but once
in place, the natural springiness of the rings holds them firmly in
place, and holds the tire as well.

Figs. 514, 515, and 516 are given to show how this ring is put
in place on a tire. Fig. 514 shows the beginning of the operation,
and the instructions for the different steps will make them clear.
Thus:

Always start with left end of the ring. Lock this in the rim as shown in
Fig. 514, so that the end of the ring is flush with the slot provided for the second
end. A dowel pin is provided to register the ring in the proper place. This must
always be correctly centered or the ring cannot be applied. This done, the balance
of the ring can be forced over the flange of the rim, as shown in Fig. 515, with the
exception of the locking end. By means of the tool, the last locking end can be

Fig. 514. Putting on a Q.D. Tire. Fig. 515. Putting on a Q.D. Tire.

The Start Forcing Flange over Rim

raised and forced over the rim into the recess provided for holding the same in posi-
tion preparatory to drawing the ends together, Fig. 516, showing the correct
position of the tool.

Then by entering the two points of the tool in the holes provided in the
ring, the ends may be drawn together, as shown in Fig. 516, and, with a slight
additional leverage, the ends of the rings can be made flush.

Before proceeding further, it should be stated that the object of
the quick-detachable rim is the quick removal of the tire, in order
to allow a quick repair or substitution of the inner tube. On the
other hand, the object of the demountable, remountable, removable,
and other rims is the removal with the tire of the rim itself to allow

317

Digitized by

Google

056 GASOLINE AUTOMOBILES

the substitution of a new tire and rim, the tire being already inflated
and ready for use as soon as applied. The object of the removable

wheel is the removal of the entire
wheel with rim and tire in order to
substitute a spare wheel with already
inflated tire.

It might be thought that these
methods called for the carrying of extra
weight, but the amount added is
actually very small, as, by their use,
tire tools and pump are dispensed with
and their weight saved.

Fig. 517 shows the former Good-
year rim. This rim, as will be noted, is of the quick-detachable type,
the idea being to remove the tire only. The rim itself has a button-
hook shape with a slight ridge, or projection, answering to the handle.
This is on the fixed side, the inner flange inside of the tire butting
against it as a stop. The tire is pushed over against this, being held

on the outside by a second
flange of similar shape. The
latter, in turn, is fixed in
place by a locking ring, a
simple split circular ring of
deep oval section. This fits
into the button-hook portion,
its contour being such as to
fit it exactly. In use, it is
sprung into place, the outer
edge of the hook on the rim
and the natural spring of the
ring preventing it from com-
ing out. This makes a very
simple and serviceable quick-
detachable rim. To make

doubly certain that the lock-
Fig. 517. Former Goodyear Universal Rim j ng r j ng CBinnot j ump ou t, a

spreader plate is attached to the valve stem; screwing this down
into place wedges the bead of the tire over against the outer flange,

318

Digitized by VjOOQlC

GASOLINE AUTOMOBILES

657

which, in turn, pushes the locking ring tight against the outer

curved part of the hooked rim. When in this locked position,

the upper part of the flange

hangs over the locking ring,

so that it cannot rise vertically,

the only manner in which it

could come off. This rim is

shown with a detachable tire in

position, but may be used with any standard clincher tire by the use

of extra clincher flanges. Fig. 518 shows the rim with a set of these

flanges in position, ready to take a standard clincher tire.

Fig. 518. Adapting Goodyear Rim to
Clincher Tirea

Fig. 519. Universal Q.D. Rim No. 2 Arranged for Clincher and Dunlop Tires

Quick-Detachable Number 2. Figs. 519 and. 520 show the
standard quick-detachable rim, now known as No. 2. This was
adopted by the Association of Licensed Automobile Manufacturers

Fig. 520. Universal Q.D. Rim with Tires in Place

as a standard and given the above name. It has the feature of
accommodating all regular clincher, or Dunlop tires. In Fig. 519, it
is shown at A ready for a clincher tire and at B ready for a Dunlop
tire, the adaptation for the straight sides being shown.

The two parts of Fig. 520 show sections of tires in place, making
clear the exact use of this reversible flange. A shows a regular
clincher tire in place, while B reveals the reversed flange in place with
a Dunlop tire. Both Figs. 519 and 520 show the construction of

319

Digitized by VjOOQIC

658

GASOLINE AUTOMOBILES

WM////M/MMMM//M

the device, the outer dropped portion of the rim having a hole through
it. The locking ring is split vertically and one end, just at the split,

carries a projection or dowel pin
• extending downward. To put the
rim on, this dowel pin must be
fitted into the hole in the rim to
give a starting place. When this
has been done, one may force the
balance of the ring into place
around the wheel with any suit-
able, thin, wedge-shaped tool.

The shape of this locking
ring with a right-angled groove in
its inner edge permits the outer
flange to overlap it, which insures
the retention of the ring when
once it has been put in place. Furthermore, it gives the outer side
flange a wider seat on the rim, thus making it more stable and longer
wearing.

As will be noted, the difference between these two rims — that is,
the old Goodyear and the Universal No. 2 — lies in the saving of one
ring and the shape of the locking ring. Both of these are called
universal rims because they may be used interchangeably for straight-

W»j?//Arjr/r/>/r»/>/>w»/M

Fig. 521. Sections through Three Popular
Q.D. Universal Kims

Fig. 522.

Latch Used for Locking Single Combination Ring which Replaces
Former Side Ring and Locking Ring

side and clincher types of tire. Other Q. D. Universals are shown in
Fig. 521, although, in the opinion of tire men, the Universal form is
slowly going out of use.

To explain these briefly, No. 1 is a modification of the Goodyear,
with different shaped inner rings, while the locking ring and the lip
formed in the felloe band to receive it are similar to those of Univer-
sal No. 2. In 2 the only difference from / lies in the locking ring,

820

Digitized by

Google

GASOLINE AUTOMOBILES

659

which has a modified Z-section, with a lip extending over the outer
edge of the felloe band. The third section differs from the other two
only in having the outer ring and locking ring combined into one, and
the felloe band changed to suit this. This combination ring is held in
place by means of a simple swinging latch, which is shown open and
closed in Fig. 522. When opened, this permits raising the end of the
ring, to which the shape of the felloe band offers no resistance. The
whole inner ring is taken off, following around the circumference of
the wheel, after which the tire is easily removed.

Quick-Detachable Clincher Forms. To return to the plain
clincher tire and the Q. D. rim, which allows of its ready removal,

y MPAW//////S////AW/////A

Fig. 523. Popular Forms of Q.D. Clincher
Rims, Shown in Sections

'////////////////////////////A,

W//M///MMMM/A>//A>.

Fig. 524. Three of the Most Widely Used
Straight Side Q.D. Rims

Fig. 523 shows four of the most prominent forms, these being indi-
cated simply as flat sections of the rim, for the tire is the same in
all cases. All these have the simple clincher edge on one side, with
removable ring and locking device on the other. That at 1 has the
same locking device shown at 2 in Fig. 521, the Z-shaped ring extend-
ing over the edge of the band. That at 2 is practically the same as
S in Fig. 521. The one seen at 3 is similar to that at 2 except for the
detailed shape of the ring as well as the lock (not shown). The
advantage of the form shown at 4 is that the outer ring is self-locking,
that is, the shape of ring and band are such that when the former

321

Digitized by

Google

660 GASOLINE AUTOMOBILES

is in place the tire itself locks it. Its only disadvantage is that
it is harder to operate than the other forms, yet despite this fact it
has been recommended for general adoption as the only Q.D. clincher
rim worth continuing.

Q.D. Type for Straight Sides. To close the subject of straight
side tires, the rims of the quick-detachable form now in use aside
from those already shown are seen in Fig. 524. Here these are seen
to be' identical with /, 2, and 4 of Fig. 523, except that the fixed
side is arranged for a straight side instead of being made with a clinch.
Here again, the last form of self-locking type has been recommended
as a standard.

Demountable Rims. All, or practically all, demountable rims
come under one of two headings — those in which the tire can be
detached on the wheel without demounting (if it is so desired) and

Fig. 525. Sections of Michelin and Empire Demountable Rims

those which are of the transversely split type and must be demounted
before the tire can be removed. In addition, there is a second division
of demountable rims into those which have a local-wedge form of
attachment and those which have a continuous holding ring, this, in
turn, being held by means of local wedges. Any of the plain demount-
ables, which will be called demountables from now on, may be of
either type of attachment, as is also the case with the first-named or
demountable detachables.

Local Wedge Type. In the so-called local wedge type, which
includes the well-known Continental forms (notably Standard
Universal Demountable No. 3 and Stanweld No. 22 and No. 30),
Michelin, Empire, Baker, Detroit, Prudden, Standard Universal
Demountables No. 1 (formerly the Marsh), and No. 2, and others,
loosening the six (or eight, as the case may be) bolts frees the rim
directly without further work. In some of these, such as the Michelin ;
the various Continentals, including Stanweld No. 22 and No. 30;

322

Digitized by VjOOQIC

GASOLINE AUTOMOBILES

56)

Detroit; Baker; and others, the wedges carry a projecving lip, which
makes it necessary to unscrew the nuts far enough to allow the
removal of the wedge so as to
pick this lip out from under
the tire-carrying rim. In
others, such as Empire, S.U.
No. 1 and No. 2, the con-
struction of the wedge and
rim is such that loosening
them frees the rim, the upper
part of the wedge or clip
swinging down to the bottom
position as soon as loosened,
because of its heavier weight
and the fact that there is no
projecting edge to prevent it.
While this latter construction
makes a faster operating rim,
it is an open question as to
whether it is as safe as the
other form. These two con-
structions are shown very
plainly in Fig. 525, in which
A is the Michelin with lipped
wedges, and B the Empire
with plain wedges.

In Fig. 526 is shown a
pair of additional demount-
ables, which are held by
the local wedgt method, the
difference here being in the
form of a wedge. Note that /
has a solid clincher rim and
2 a straight side rim. The
base, however, is the same
for both and, as will be seen ^ 527 ^^x Drawing showing. Con-

by examining this, has tWO -trucUon of Baker Demountable Run

curves in its upper surface, the straight side rim fitting into the lower

Fig. 526. Two Popular Demountable Rim Forma
— for Clincher Tirea above, for Straight Side below

323

Digitized by

Google

662 GASOLINE AUTOMOBILES

or bottom one, while the clincher form of rim fits into the upper one.

Note, also, that the wedges are the same for these two. This makes

the demountable parts
of the rim practically
universal in that the
owner can change from
clincher to straight side
or vice versa by simply
purchasing the extra set
of tire-carrying rims,
no change in the wheels
or means of attachment
being necessary. For
this reason, the felloe
band shown under these
two rims has been sug-

Ife 528. The First Operation in Removing Baker &**** M a Standard for

Demountable — -Loosening the Bolts demOUIl tables.

Process of Changing Baker Local Wedge Type. In Fig. 527 is
show r n the Baker, which, as mentioned previously, is of the local

wedge type of demount-
able, having a trans-
versely split rim which-
must be removed from
the wheel before the tire
can be taken off. Per-
haps this whole action
will be shown more
clearly by the progres-
sive series of views, Figs.
528 to 538, which show
the various steps in re-
moving and replacing a
tire and tube mounted on
a Baker rim, the same as

Fig. 529. Second Baker Demounting Operation — . . .

Jacking the Wheel and Starting to Pry off Rim is shown in Section in

Fig. 526. First, all the wedge bolts except the two nearest the valve
stem, one on either side, are loosened by means of the special brace

Digitized by CjOOQIC

GASOLINE AUTOMOBILES 663

until the wedges swing out and down, as shown in Fig. 528. As

mentioned previously, this means quite a little loosening, for the

wedges have a long lip

which projects under the

tire-carrying rim. When

this has been done, and

as each one swings down

•out of the way, it is

tightened just enough to

prevent the wedges from

swinging back.

This done, the wheel
is jacked up off the
ground, as shown in Fig.

529, and the point of the
tire tool is inserted be-
tween the felloe band

. . Pig. 530. Third Baker Operation— Putting on New Tire

and the rim carrying the and Lowering wheel

tire at the point opposite the valve, where, it will be remembered, the
wedges were loosened, and the rim will be almost free. By prying
the tire-carrying rim out-
ward and working around
it toward the valve and
back again, it will finally
be loosened to a point
where, with the valve at
the bottom, the rim and
tire can be slipped off
without lifting it. The
extra tire and rim are
now put in place.

This is shown in Fig.

530, where the reverse % of
the operations shown in

Fig. 529 and JUSt de- ^ ^ Fourth Operation— Tightening Bolts on

scribed is followed, that the New Tire and Him

is, the valve stem hole is revolved to the top, the valve stem inserted,

the rim pressed into place all around, then the wheel is revolved until

325

664 GASOLINE AUTOMOBILES

Fig. 532 Fifth Operation— Starting to Take Fig. 533. Sixth Operation— Forcing Down the

the Rim out of the Tire — Beginning Short End of Rim

to Pry Short End

Fig. 534. Seventh Operation — Prying under Fig. 535. Eighth Operation — Raising the Frer

the Loose End of Rim End of Rim, Using Roth Hands

FJg. 536. Ninth Operation— Inserting Fig. 537. Tenth Operation— Prying Tir«

Valve Stem and Beads in Away from Rim to Let Latter

End of Rim Slip into Place

326 Digitized by GOQQle

GASOLINE AUTOMOBILES 666

the valve stem comes to the bottom, so that the two wedges
which have not been loosened are nearest the ground. Then the jack
is let down and removed, the whole weight of the wheel coming on
the bottom point where the wedges are already tight, never having
been loosened.

This action is necessary as, with the weight on the other points
where wedges are still loose, it would be necessary to work against
the car weight. At this point, as Fig. 531 shows, the nuts are loosetied,
using the special brace until the wedges can be inserted under the
rim. This done, the nuts are tightened to hold them there. This
tightening is continued until the little studs, or lips, in the rim rest
on top of the outside edge of the felloe band, using the tire tool to
force them in, if necessary. The new tire carried is supposed to be
ready for use, that is, inflated to the proper pressure, so that these
four actions complete the work of making a roadside change.

When it is desired to repair the tire which has been removed,
it is carried home on its rim just as taken off the car wheel, and the
rim is removed from the casing as follows: Rim and tire are laid
flat on the garage floor, as shown in Fig. 532, so that the outer end
of the diagonal cut in the inside of the rim which is farthest from the
valve stem is uppermost. An inside plate will be found on the rim
which covers the two rivet heads on either side of the cut, with a
central hole for the valve stem. This plate is called the anchor plate
and must be removed. To do this, begin at the short end of the rim,
which does not have the valve stem — as, in this position, it will be
held in the long end — and insert the sharp end of the tire tool or a
screwdriver under the bead or between the bead and the rim.

These two actions, as shown in Fig. 533, bring the two short
sides of the rim closer together and thus reduce the diameter. When
the extreme end has been freed in this way, the operation is repeated
some 5 6t 6 inches farther around, that is, that much farther away
from the slit. This done, a considerable portion of one end will be
free. Then turn the rim and tire over so that this free part comes at
the top instead of at the bottom and, standing on the part which is
still tight, insert the tool between the rim and the entire tire.

This frees the entire end, but, to make sure, the tool must be
moved a little farther along so as to free more of it. When enough has
been freed to allow grasping it with both hands, as shown in Fig. 535,

327

Digitized by

Google

666 GASOLINE AUTOMOBILES

the tool is dispensed with and, taking a firm grip on the rim, at the
same time standing on the tire at the point where tire and rim still
contact, pull upward strongly. When followed all the way around
this pulls the rim entirely out of the tire.

Having the casing and tube free, they may now be inspected and
repaired. When this is done, or if it is not done, and a new tire or tube
or both are used, the worker is ready now to replace the rim. This is
practically the reverse of the method just followed out. As shown in
Fig. 536, the rim is laid on the floor; then the end which has the valve-
stem hole drilled in it is raised, and the valve stem inserted. Next
the beads are pulled into the rim, it being necessary to press them
together somewhat tightly in order to do this, but, with a little prac-
tice, it soon becomes an easy matter. All this is done with the other
part of the rim underneath the tire.

The inserted end of the rim is followe^ around with the thin
end of the tire tool, as shown in Fig. 537, the position of the tire

ftbove the rim allowing the work-
man to stand on it and thus use
his weight to press the two sides
of the tire together and, at the
same time, to force them into the
rim. This operation is followed
right around the inside circum-
ference of the tire, the free, or

Fig. 538. Eleventh Ooeration-Inserting Sn0rt > end ° f the rim ^nig the

Anchor P late ^ ^ ^ enter Q n account Q f

the shape of the joint or cut in it, this should slip readily into its
proper place, but if it does not, the thin end of the tool can be used to
pry it into place, or a hammer can be used on the longer side to
drive it in.

The rim being fitted snugly into place all around, the anchor
plate is inserted, Fig. 538, to prevent the short end slipping out again,
and the tire is ready for inflation. If it is to be carried as a spare
tire, the dust cap should be screwed into place over the valve stem,
so as to preserve the threads which might be damaged in handling.

Rim with Straight Split. This covers the action of practically all
the demountables in which the transversely split rim is used, necessi-
tating the removal of the rim and tire from the wheel before the

Digitized by CjOOQIC

GASOLINE AUTOMOBILES

667

Fig. 539. One-Piece Rim, Showing Right- Angled

Split and Locking Device

Courtesy of Standard Welding Company, Cleveland, Ohio

tire can be taken off the rim. However, not all rims are split on a
diagonal as is this one, and Fig. 539 is presented to show this single
feature on another rim, which otherwise is somewhat similar. Here
the rim is split at right
angles, having a plain thin
rectangular plate A attached
to the free end, or that which
is removed first, while the
other end has a swinging flat
tapered plate with a cam-
shaped end B, the action of
which is to expand the rim
to its fullest diameter and
lock it there. In the top
figure, it is locked — that is,
the rim is expanded as it
would be when in use and just
after it had been removed for
replacement. When the rim
is to be removed from the
tire, the latch B is swung out
of the way, as shown in the
lower figure, when the catch
C which holds the two ends
together can be opened by
lifting the tire with this
portion at the bottom and
then dropping it a couple of
times. This done — usually
this action will be accom-
panied by the free end spring
inside the fixed end — con-
tinuation of the removal is an
easy matter. The rim shown
is the Stanweld No. 20.

Comparison of Continuous Holding Ring Type with Local Wedge
Type. To return to demountable-detachable rims, these may and do
include a number of those quick-detachable forms previously shown

Fig.

540. Sections through Two Popular Forms
of Demountable-Detachable Rims

329

Digitized by

Google

668

GASOLINE AUTOMOBILES

and described. In Fig. 540, a pair of typical forms is shown, that at
1 being fitted for a clincher tire, while that at 2 is for a straight side.
Looking at the detachable part of the rim, 1 will be recognized as
that previously shown at 3, Fig. 521, where it was described as a
universal rim, the inversion of the two rings Converting it from a
clincher to a straight side, or vice versa. Similarly, 2 will be recog-
nized as the form of detachable shown at 3 in Fig. 524.

Here, however, both are fitted to be used as demountables,
this being accomplished by the formation on the under side of the
band of a pair of wedge-shaped projections. The felloe band is so
made and applied that it forms one surface to contact with one of
these wedges, while the other is formed variously. At 1, a separate
ring is used with the flat outside clips to hold this against both

felloe band and rim, while at
2 the wedges or clips have
an extension which presses
against the outer wedge on
the rim. This latter distinc-
tion divides these two into
the two classes mentioned
previously — one into the
continuous holding ring class,
the other into the local
wedge type.

These forms are shown
to illustrate this point and
also because, despite this
difference, they have practically similar felloe bands. This felloe
band — that is, of the form shown in 2 — has been recommended as a
standard for all demountable-detachable rims. Another and different
example of the clamping-ring demountable-detachable type is shown
in Fig. 541, this being the Firestone rim. Here, it will be noted, is
the felloe band just mentioned, while the detachable-rim portion is
that previously shown at 1 in Fig. 523 as having the Z-shaped locking
ring and being adapted to clincher tires only. The rim band is
made with the two wedge-shaped projections on its underside.

Perlman Rim Patents. Late in the summer of 1915, considerable
consternation was caused among tire and rim manufacturers when

DEMOUNTABLE
MM BOLT

V4LKE SLEEVE

0C/ST CAP-

CLAMPtNG R/NQ

CLAMP
/VUT

CLAMP
CLAMP 3/fAOtET

Fig. 541.

Section of Tire and Rim of Firestone
Demountable Tire

330

Digitized by

Google

GASOLINE AUTOMOBILES

it became known that the Perlman rim patent had been adjudged
basic by the courts, and that, on the strength of this decision, an
injunction had been issued against the Standard Welding Company,
of Cleveland, Ohio, some few of whose rims have been previously
described. Perlman's original patent was applied for on June 29,
1906, and, in addition to this record, the fact was established that
the owner had a Welch car which had traveled over 150,000 miles
and on which were a set of the original rims. The case dragged
through the courts and was discontinued some seven or eight years
ago. Perlman persisted, however, although he had to revise and
alter his application many times; the basic patents were finally
allowed, and issued to him in February, 1913. This means, of course,
that the patent will not expire until
the year 1930.

Perlman's locking elements and
the principle involved are shown in
Fig. 542, which is a section through
the rim and felloe. In Perlman's suit,
it was claimed that the wedge end of
the bolt which was covered in his
patent, included all wedge-operating
rims, whether actuated from the
center, as in Fig. 542, or from the side.
This contention was supported by the
court, and negotiations are now in process between Perlman and many
manufacturers of the so-called local wedge type of rim. As this would
appear to cover all the rims shown and described in Figs. 525 to 541,
inclusive, the influence of this decision upon the industry can be
imagined. Moreover, the length of time which this basic patent has
to run precludes the possibility of delaying action by prolongation
of suits, as has been done in similar cases. A notable example of
this is the case of the Selden automobile patents, which were fought
on one ground or another over a long period of years.

Standard Sizes of Tires and Rims. As might have been noted
in going over the above discussion of tires, plain rims, detachable
rims, and, finally, demountable rims, all these different constructions
require widely differing wheel sizes. It has been proposed to stand-
ardize wheels, that is, the outside diameter of the felloe and with

Fig. 542. Section of Perlman Rim,
Showing Locking Device

SSI

Digitized by

Google

670

GASOLINE AUTOMOBILES

it the thickness of felloe bands as well as their shapes or contours,
one for each tire cross-section. The proposed reduction of tire sizes
to nine standards is as follows: 30- by 3-inch, 30- by 3J-inch, 32- by
3J-inch, 32- by 4-inch, 34- by 4J-inch, 36- by 4J-inch, 38- by 5J-inch
and probably 36- by 5-inch, supplying these sizes and these only to
manufacturers of cars; additional oversizes are allowed for car users,
one for each size above, that is, 31- by 3J-inch for 30- by 3-inch, 31-

Tine Seal Line

D Sections 3k"

felloes fbr*J,*JO

felloes for

/fit One Piece

KelseyRi/m

Firestone Rims

Stan»etJ

Slonwetef

Split ftims

*40mms

*60Rims

G Sections Si #6 *
Fig. 543. Typical Felipe, Band, and Him Sections for Popular Demountable Rims

by 4-inch for 30- by 3J-inch, 33- by 4-inch for 32- by 3£-inch, 33- by
4J-inch for 32- by 4-inch, 35- by 4^-inch for 34- by 4-inch, 35- by 5-
inch for 34- by 4£-inch, 37- by 5-inch for 36- by 4£-inch, 39- by 6-inch
for 38- by 5£-inch and probably 37- by 5^-inch for the 36- by 5-inch.
Rim standardization will follow the adoption of these sizes. In this
event, the standardization of demountable rims will come in time.
At the present, there is a wide range of difference, as will be
noted in the drawing, Fig. 543, which shows felloes for the most

332

Digitized by

Google

GASOLINE AUTOMOBILES

671

Fig. 544. Operating Device on the Ashley-
Mover Double Q.D. Rim for Wire Wheels

widely used demountable rims, depicting the band and rim in each

case. The drawing should be read crosswise, each horizontal line

showing the differences to be

found in the makes mentioned in

that particular tire cross-section

size. Thus, the D sections show

the differences for 3J-inch tires,

E those for 4-inch tires, F those

for 4$- and 5-inch tires, and G

those for 5£- and 6-inch tires,

rims for which are not produced

by all makers.

Other Removable Forms.
Outside of the regular range of
wood w T heels and the standard
tires for them, any different wheel
calls for a different treatment.
As has already been mentioned
under the subject of Wire Wheels,
few of these have anything but a
solid one-piece clincher rim; first,
because the wheel itself is remov-
able, thus making it as easy to
change wheels as to change rims
in the ordinary case; and second,
to save weight and complication.

Demountable for Wire Wheels.
However, demountable forms
have been produced for wire
wheels, one being shown in Figs.
544 and 545. This is the G-R-C
double Q.D. rim as the makers
prefer to call it, in action a de-
mountable-detachable form, the
clincher rim being of the straight
split type, in fact, a Stanweld
No. 20. This is made with a
double wedging surface on the

Fig. 545. Section through Rim and Band of

G-R-C Rim. Showing Wedging

Band and Its Operation

333

Digitized by

Google

672 GASOLINE AUTOMOBILES

outside and a single one on the inside. The latter contacts with
another on the false rim to which the wire spokes are attached, as does
also the inner wedging surface on the outer wedge. The outer wedg-
ing surface is made so as to come just above a fairly deep slot in the
false rim. In this is placed a ring with a double wedge-shaped upper
edge and a square lower edge. This ring is split at one point and
locked in the highest position at the point diametrically opposite.

At the split point, a pair of bent-arm levers, Fig. 544, are
connected to the two ends. Attached to a middle point of each of

these is one end of an inverted U-
shaped member, the center and
upper part of which form a bear-
ing for a locking stud, which is
attached to one end of the ring.
Above this is placed a nut. As
will be noted, this forms a toggle
motion, the action of which is
to expand the whole ring when
the nut is screwed down and to
contract it when the nut is
screwed up.

This is the precise action
used, the single ring forming the
whole locking means, and being

F*. 546. Construction of Parker Hydraulic actuated by the toggle mech-

s ^ lW i^^^^tr°^ tiono( ™ism through the medium of

screwing the nut up or down.
While at its best on wire wheels because of its simplicity, this rim
is, of course, applicable to wood wheels. At present, its makers
are specializing on the wire-wheel forms.

Parker Rim-Locking Device. Another rim-locking device which
does not come under any of the standard divisions, being devised
for use on the Parker hydraulic wheel, previously shown in Fig.
502, is the Parker modification of the former Healy rim. As shown
in Fig. 546, which shows the end of a steel spoke in section, this is
made with a cup at the upper and inner end, while at the outer is
a loose clip, through which passes a bolt with a head on the outside.
Tightening the bolt by means of the external head draws the clip

334

Digitized by

Google

tJASOLINE AUTOMOBILES 673

up the incline at the bottom of the cup, against the wedge on the
underside of the rim, the amount of pressure exerted depending
solely upon that applied to the bolt head. As the two wedge shapes
oppose each other, this holds the rim as firmly as is possible. It
will be noted that this construction does away altogether with the
use of felloe bands or false rims used on other forms of rims or wheels,
thus saving much weight. Moreover, a great part of the weight
is saved at the outside, where the flywheel effect of rapid rotation
is thus lessened. Moreover, the absence of additional metal here
would give the tire more chance to radiate its heat, and thus would
preserve it better. This construction, considering its many advan-
tages, should have a wide use.

Similarly, with all demountable rims, the tendency is toward
wider use, with which comes lower cost, as well as a better under-
standing of their use, abuse, attachment, and detachment. With
the standardization of tires to a few standard sizes, say 9 instead
of 54, it will be only a few years before all kinds of rims, including
demountables, will be standardized, at which time the latter will
come into universal use.

TIRE CONSTRUCTION

Composition and Manufacture. Tires consist of two parts, the
tube and the shoe, or casing. The former is a plain ring of circular
cross-section, made of pure rubber, containing an air valve, and is
intended only to hold the air. The shoe, or casing, on the other
hand, provides the wearing surface, protects the air container within
from all road and other injuries, and constitutes or incorporates the
method of fastening itself to the wheel. In its construction are
included fabric — preferably cotton — some pure rubber, and much
rubber composition, the whole being baked into a complete unit by heat
in the presence of sulphur, which acts somewhat as a flux for rubber.

Considering a typical tire, there enters into its make-up, starting
from the inside, six or seven strips of frictional fabric, that is, thin
sheets of pure gum rubber rolled into intimate contact with each
side of the cotton, making it really a rubber-coated material. Next,
there is the so-called padding, which is more or less pure rubber, has
a maximum thickness at the center of the tread, and tapers off to
nothing at the sides, but usually carrying down to the beading.

335

Digitized by

Google

674

GASOLINE AUTOMOBILES

Above this tnere is placed a breaker strip, consisting of two or three
layers of frictioned fabric impregnated m a rubber composition.
This, too, is thickest at the center and tapers off to the sides, but
ends at the edge of the tread. Finally, there is the surface covering,
called by rubber men the tread; this contains very little pure rubber,
being thickest at the center and extending with gradually decreased

thickness almost down to the
bead.

The last two of this series of
layers constitute the real wearing
surface of the tire, and when the
surface is so worn that the breaker
strip may be seen, it is time to
have the tire retreaded. When
the wear has gone through this,
if the padding be fairly complete,
retreading will still save the tire,
but if wear has gone clear down
through that so as to expose the
fabric, the show must be run to a
finish and then discarded.

All this construction can be
noted in Fig. 547, which shows a
section through a tire, with the
inner tube in place, the section
being taken so as to pass through
the center of the tire valve. This
should be borne in mind when
examining this figure, for the
location of the inner tube inside
the tire, as previously described,
is likely to be misleading.

Bead. In the reference to
tire construction, no mention has been made of the bead. This is a
highly important part of the tire, for it is the part which holds
it in place on the wheel. It is made of a fairly hard rubber
composition, the fabric being carried down on the sides so as to cover
it. In a cross-section, it has a shape very close to an equilateral

Bead

Filler

Inside

Rg. 547. Section through Assembled Tire and

Tube, Showing Construction and Part*

of the Tire and Tire Valve

336

Digitized by

Google

GASOLINE AUTOMOBILES 675

triangle resting on its base; around the wheel it is curved to fit the rim.
The method of attaching the tire has a considerable influence on bead
construction, since, in the clincher type of tire, in which the shoe must
be stretched on over the rim, the bead must be extensible in order to
insure easy mounting. In the quick-detachable and straight-side
forms of tire there is no need for this stretching, so the bead can be
made of stiff and rigid material as well as cut down somewhat in size.

The straight-side or Dunlop type of tire is seldom made with
much of any bead, the layers of fabric being carried straight down.
A more modern form of tire has a
pair of woven-wire cables incor-
porated in the bead to make it
stiffer and stronger, and this is
said to have been very successful.
As has been pointed out pre-
viously, this could be done only
with the quick-detachable form,
not with the clincher type.

In both the clincher and the
quick-detachable forms, the bead
holds the tire to the wheel by
means of parts of the rim, which
bear on it from above, as well as
sidewise, the internal pressure
when the tire is inflated pressing „. _„ „. ,„,... . .

r ° Fig. 548. Views of Tire Valve, Showing

it against these parts very firmly. closed and P* n Positions

In both the clincher and the quick-detachable forms, the bead
holds the tire to the wheel by means of parts of the rim, which bear
on it from above, as well as sidewise, the internal pressure when
the tire is inflated pressing it against these parts very firmly.

Tire Valves. In Fig. 547 there is shown a section through the
tire valve but on a small scale. As this is a very important part
and little understood, a larger view is shown in Fig. 548. This is in
two parts, A at the left showing the valve closed, and B at the right
indicating the position of the various parts when the valve is open.
Note that the lower part of the valve is hollow, so that air inside of
the tire has access to the valve seat. Note that the valve is held
down on this by the threaded portion above it. This valve seat

337

Digitized by

Google

676 GASOLINE AUTOMOBILES

forms a slight taper which rests against an equally slight taper
inside of the valve stem.

One condition of the tire valve holding air pressure is that the
two valve seats be clean and smooth and free from scratches or cuts
and foreign matter. Now it will be observed that the valve-seat
portion of the valve has a hole through the center, in which the
stem is a loose fit. This large hole passes all the way up through the
threaded portion. The stem has a projection below the valve seat,
which normally is held up against the bottom of the seat by the
spring, this being strong enough to hold it up so tightly that no air
can pass between the two. There are other conditions for valve
tightness. The spring must be strong enough to hold these parts
together; and the surfaces must be clean and true so that when
held together, no air can get through.

Action of Valve. The action of the valve is this: When air
is pumped in, it passes down around the central stem until it
meets the projection, which it forces down against the pressure of
the spring and, when there is air inside, against the pressure of the
internal air. As soon as this is pressed down, the air passes in, and
if the external pressure is stopped, as at the end of a stroke of the
pump, the spring and the internal pressure push the projection
back into place, and no air can escape. On the next pressure stroke
of the pump, this is repeated, the whole process continuing until the
tire is filled.

Leaky Valves. It will be noted that with a good clean spring,
projection, and valve seat, the pressure of the air itself holds the
valve tight. Thus, when a valve leaks, it is a sure sign that some
part or parts of it are not in good condition. If the valve is not
screwed down far enough, air can leak out around the valve seat,
so that leakage may be remedied by screwing the whole valve farther
down into the stem. If the valve stem is too tight a fit in the central
hole, it may stick in a position which allows air to pass. This can
be remedied by a drop of oil placed on the stem and allowed to
run down it. But not more than one drop should be used as oil is
the greatest enemy of rubber, and the tube with which the valve
communicates is nearly pure rubber.

If the spring is too weak to hold the projection against the
bottom of the valve seat, the valve will leak. This can be remedied

338

Digitized by

Google

GASOLINE AUTOMOBILES 677

by taking out and cleaning the spring, also stretching it as much at
possible. In general^ however, the best plan of action with a
troublesome tire valve is to screw it out and put in a new one. These
can be bought for fifty cents a dozen, and every motorist should
carry a dozen in a sealed envelope, also a combination valve tool.
When trouble arises with the valve, or a tire leaks down flat with
no apparent cause, screw out the valve with the tool, screw
in a new one, make sure it is down tight, and pump up again. The
few cents it will cost to throw away a valve, even if it should hap-
pen to be good, will be more then compensated for by the time
saved. Another point is that the whole valve assembly is so very
small that it is difficult to handle.

Washing tires often is a good practice, since water does them no
harm, while all road and car oils and greases will be cleaned off,
nearly all of these being injurious. Frequent washing will also serve
to call the attention of the owner to minor defects while they are still
small enough to be easily repaired, and thus they are prevented from
spreading. When not in use, tires should be wrapped, so as to be
covered from the light, and put away in a dry room in which the
temperature is fairly constant the year round. They will not stand
much sunlight, nor many changes in temperature. Cold hardens
the tires and causes the rubber to crack. Heat has a somewhat
similar effect and also draws out its life and spring.

In general, of all things to be cared for and repaired promptly,
no one thing is of more importance than the tires. If this rule is
kept in mind, better satisfaction in the use of the car will result.
So, too, with other repair work; if tools and appliances are made
available and repairs made as soon as needed, the car will be better
understood and give more satisfaction than if the opposite course
be pursued. A few months of use of a car will do more to emphasize
this than any amount of talk. Keep your car in good condition
and you will reap the benefits of the little work you do upon it.

TIRE REPAIRS
Repair Equipment

Vulcanization of Tires for Repair Man. In practically all of the
following material the point of view is that of the professional repair
man, or of the garage man about to take up tire repairs, as dis-

339

Digitized by

Google

678 GASOLINE AUTOMOBILES

tinguished from that of the average owner or amateur repairer. Tbe
lesser tire injuries and their repairs are handled from an amateur
standpoint in another part of this work.

Vulcanization, to the unitiated, sounds very mysterious, but
it really is nothing more or less than cooking, or curing, raw gum

Fig. 549. Small Vulcanizing Outfit for Single Casing of Six Inner Tubes
Courtesy of C. A. Sfialer Company, Waupun, Wisconsin

rubber. In the processes of manufacture a tire is cooked, or cured,
all the component parts supposedly being united into one complete
whole. A tire is repaired preferably with raw gum or fabric prepared
with raw gum, and, in order to unite this to the tire, vulcanization
or curing is necessary. The curing, in addition to uniting the parts

igitizedby VjOOQl€

GASOLINE AUTOMOBILES 679

properly, gives the proper strength, or wear-resisting qualities, which
raw rubber lacks.

Types of Vulcanizing Outfits. Shaler Vulcanizer. This curing,
or cooking, is done by the application of heat, in a variety of ways.
Generally, very small individual vulcanizers have a gasoline or
alcohol cavity, holding just enough of the liquid so that when lighted
and burned the correct temperature will be reached and held for the
correct length of time. The larger units are operated by steam or
electricity; the latter is preferred for its convenience, but the former is
used by the majority of repair men. The source of heat is immaterial
so long as the correct temperature is reached and maintained for
the right lengh of lime. Too hot a vulcanizer will burn the rubber,
while too low a temperature will not give a complete cure.

For the average small repair man, the outfit shown in Fig. 549
will do very nicely, at least to start with. This will handle a single
casing or six tubes, or in a press of work, both simultaneously. This
outfit is operated by gasoline, contained in the tank shown above
at the right, but the same outfit can be had with pipe arrangements
for connecting to a steam main, or for electric heating. In the case
of either gasoline or steam, there is an automatic temperature con-
trolling device which is a feature of the Shaler apparatus. As shown,
casings are repaired by what is known as the "wrapped tread method",
the repair being heated from both inside and outside at once, the
outside being wrapped. Tubes are handled on the flat plate, shown
in the middle of the framework, the size of which is 4£ by 30 inches,
this being sufficient, so the makers say, to handle six tubes at once.

Haywood Vulcanizer. For larger work, a machine something
like the Haywood Master, shown in Fig. 550, is excellent. This is
a self-contained unit, carrying its own gasoline tank, steam generator,
and other parts. It handles four casings at once, while the tube
plate G, 5 by 18 inches, is large enough for from three to four tubes,
according to the allowance per tube made in the Shaler outfit. The
separate vulcanizers are not designed for the same part of a casing,
a side wall and bead vulcanizer being shown at 7), a sectional vul-
canizer for large sizes at E, a sectional vulcanizer for small and
medium sizes at F, and a side wall and bead vulcanizer for both
clincher and straight-side tires at H. The gasoline tank is marked
C, with vertical pipe in which is the gasoline cut-off valve K. This

341

Google

680 GASOLINE AUTOMOBILES

leads down to the gasoline burner M , where the gasoline in burning
vaporizes the water into steam. The water gage L, which indicates
the amount of water available, is placed on the side of the steam
generator A. Above this steam generator is the steam dome at B,

Fig. 550. Master Vulcanieer with Self-Contained Steam Generator
Courtesy of Haywood Tire and Equipment Company, Indianapoli*, Indiana

from which the steam pipes lead to the various molds. The returns,
or rather drips, will be noted, also the steam gage (not marked) and
the cut-off valve in the supply pipe to the sectional molds. In addi-
tion to the molds shown and a full supply of parts and tools, sec-
tional vulcanizers for 2\- and 3-inch tires, relining mold for 2J-, 3-,

342

Digitized by

Google

GASOLINE AUTOMOBILES 681

and 3J-inch tires, and relining mold for 4-, 4 £-, 5-. and 5£-inch casings
come with the device.

This outfit with the extra molds, described but not shown, gives
a very complete equipment for the small shop doing average

Fig. 551. Battery of Vulcanizing Mold for Various Sites of Tires

repairing. In fact, when a shop outgrows this type of equipment,
it must specialize in tire work and purchase special equipment.

Separate Casing Molds for Patch Work. In the way of sepa-
rate molds for casings, An excellent example of the localized heat
type is shown in Fig. 551. By this is meant the form designed to
vulcanize a small short section of a tire. The illustration shows
five sections capable of handling, respectively, 2\-, to 3-inch (motor-
cycle), 2 J- to 3-inch (small car), 3£- to 4-inch, 4j- to 5-inch, and 5 \- to
6-inch tires, thus covering the entire range. These molds have a
special arrangement in that the heating portion is divided into three
sections, into each of which steam can be admitted separately. This
allows the use of one, two, or all the sections, according to the nature
of the repair.

In Fig. 552 is shown how it is
possible, with this apparatus, to vul-
canize the tread portion only by
admitting steam solely to the larger
bottom steam chamber around the
tread, similarly, with the right-hand
bead or side wall or the left-hand bead
or side wall. When a complete sec-
tion is to be vulcanized, all sections „. „ , . , .

Fig. 552. Section of V ulcamzer,

are opened. The importance of this showing steam Cavities

will be realized in a simple consideration of the fact that the tire itself
has already been vulcanized and further heat is not only not good for
it, but is distinctly bad, as it deteriorates the rubber. Where the heat

343

Google

682

GASOLINE AUTOMOBILES

is needed, however, is not the raw rubber which has just been added at

the repair point, this being practically useless until it has been cured.
Vulcanizing Kettles. Horizontal Type. When it comes to

vulcanizing an entire tire, as, for instance, when a new tread has been

put on, or other very large repair,
what is known in the trade as
a "kettle" is needed. This is
simply a heavy steel tank, large
enough to take one or more entire
tires, steam being admitted to its
interior to vulcanize them. The
kettle shown in Fig. 553 has a
capacity of two casings 36 inches
in diameter or smaller. It is of
the type in which no bolts or nuts
are used for fastening the cover,
this being held fast by the pro-
jecting lugs which lock under
other projections on the top of
the kettle when the cover is
turned. A special rubber pack-
ing ring also is used, Fig. 554,
effectually sealing the kettle

against steam leakage. This kettle resembles a doughnut in shape,

the tires lying within the circular cavity.

Fig. 553. Vulcanising Kettle, Horizontal
Type

Teat Cock

5o f efy Vafr&,

Test Cock.
&low Off
^^-To Return or- T>-ap

Fig. 554. Section of Horizontal Vulcanising Kettle

Large Vertical Type. When the work goes beyond the capacity
of size and type of tank or kettle shown in Fig. 553, which will handle

344

Digitized by

Google

GASOLINE AUTOMOBILES

683

two casings at a time, and at least two, perhaps four, kettles full
an hour, that is, from 40 to 75 casings a day, it becomes necessary
to use a larger type of kettle, made in vertical types only. These
consist simply of large round steel shells with hinged heads, into

Fig^555. Shaler Electrically Heated Inside Casing Form

which the tires can be rolled and piled, after which steam is admitted to
the whole interior. They vary in size from 36 inches inside diameter
by 24 inches in length to 48 inches diameter by 40 inches in length.

Inside Casing Forms. Another
requisite of the tire specialist is an
inside casing form, such as is shown
in Fig. 555, or something similar.
Many tire repairs are inside work,
and even on those which are
external, it js important to have an
inside form against which the tire
can be pressed and firmly held while
vulcanizing. This particular form
is heated by electricity, the wires
being shown at the left; it is 14
inches long and has an external
shape to fit the inside of all casings.

Side-Wall Vulcanizer. A shop doing a great deal of work can
use to good advantage the side-wall vulcanizer shown in Fig. 556,

Fig. ^556. Side-Wall Vulcaniier

345

Digitized by

Google

6S4 GASOLINE AUTOMOBILES

It has a single central member through which the steam passes, and
also has bolted-on side plates, the insides of which are formed to suit
either clincher or straight-side tires. In the figure, the side plates are
not both in place, one being shown on the work table below. The
brace shown is used to remove the clamping nuts quickly and easily.
This form is very useful on all side-wall or bead operations. It applies
greater pressure along these parts of the tire than an air bag; it exactly

Fig. 557. Retreading Vulcaniier with Tire in Position
Courtesy of Haywood Tire and Equipment Company, Indianapolis, Indiana

fits the tire, and the size and shape make it possible to vulcanize a
36-inch tire in four settings.

Retreading Vulcanizers. Retreading vulcanizers differ from
the sectional molds of Figs. 549, 550, and 551 in that the heat is
applied at one particular point or, rather, strip along the middle of
the top surface of the casing and extending down only as far as
the side walls. Such a device, shown in elevation in Fig. 557, and
in enlarged sectional detail in Fig. 558, is used solely for retreading
or vulcanizing a new tread strip around the tire. The complete
unit extends around ?bout one-third of the whole tire surface so that

S46

Google

GASOLINE AUTOMOBILES 685

when putting on a complete new tread the mold must be used three
times. The section, Fig. 558, is numbered as follows: casing, 2;
inner mold, 1; new tread to be vulcanized, 3; vulcanizer proper, 4;
clamp, 5; and steam space within which the heating is done, 6.

Layouts of Equipment. There are two ways of installing an
outfit somewhat like that just described, namely, by the non-return
system and by the gravity-
return system.

Non-Return Layout. A
typical installation according
to the non-return system is
shown in Fig. 559. A steam
trap must be placed in the
system to remove the water
and discharge it either into
the sewer or into a tank so
that it can be used again.
In the figure there is shown a
tube plate, a three-cavity
sectional vulcanizer, two in-
side molds, and a medium
size kettle of the vertical type
placed in order from right
to left. A pressure-reducing
valve is shown which permits
the use of a higher pressure
in the boiler, thus maintain-
ing an even steady pressure

- , n Fig. 558. Section of Retarding Vulcaniser

On the VUlcaniZerS regardleSS Courtesy of Haywood Tire and Equipment

m a a a • x xi. i_ "I Company, Indianapolis, Indiana

of fluctuations at the boiler.

Gravity-Return Layout. When the coil steam-generator or flash
type of boiler is used, the gravity-return system is utilized, this being
a method of piping by means of which the condensed steam is returned
to the coil heater to be used over again. This makes it necessary to
set the apparatus so that the water of condensation will run back to
the coil heater, which means that the pieces must be in a series, each
successive one being set a little lower down to the boiler. Figs.
560 and 561 show a side view and plan view, respectively, of a small

347

Digitized by

Google

686

GASOLINE AUTOMOBILES

348

Digitized by

Google

GASOLINE AUTOMOBILES 687

plant arranged on this plan. The outfit consists of the coil heater,
which may be fitted to burn gas or gasoline, two inside molds, a large
tube plate, and a three-cavity sectional vulcanizer. The outfit

Fig. 500. Elevation of Gravity-Return Vulcanising Plant

differs from Fig. 559 only in the absence of the kettle; on the other
hand, the tube plate in Fig. 560 is larger.

Small Tool Equipment In addition to these larger units, the
well equipped tire repair shop should have a considerable quantity
of small tools, among the necessities being those shown in Fig. 562.
At A is shown a flat hand roller and at B a concave roller. C shows
an awl, or probe, which is used for opening air bubbles and sand blis-
ters. D is a smooth stitcher; F a rubber knife, of which two sizes are
advisable, a large and a small; and G a 10-inch pair of shears for

Pig. 561. Plan View of Gravity-Return Vulcanising Plant

trimming inner tube holes, cutting sheet rubber, etc. H is a steel
wire brush for roughing casings by hand; a preferable form is a
rotary steel wire type driven by power at high speed. / is a similar

349

Digitized by

Google

688

GASOLINE AUTOMOBILES

wire brush for roughing tubes; and J another brush with longer
wires, also for roughing casings; K is a tread gage for marking
casings to be retreaded; and L a fabric knife necessary in stepping
down plies of fabric, if is a pair of plug pliers for placing patches
inside of small tube repairs; N is a cement brush for heavy casing
cement, another very much smaller and lighter one — preferably of
the camel's hair type — being used for tube cement. is a hand

Fig. 562. Collection of Tools Necessary for Vulcanising Work

scraper and P a tread chisel; Q performs a somewhat similar function,
being a casing scraper for cleaning the inside of a casing preparatory
to mending a blowout.

In addition to the small tools shown in Fig. 562, it is necessary
to have several tube-splicing mandrels; a large number of various
sizes and shapes of clamps for all purposes; rules, try-squares and
other measuring tools; tweezers for handling small patches, tools
for recutting threads on tire valves; tire spreaders, for holding casings

350

Digitized by

Google

GASOLINE AUTOMOBILES 689

open when working inside; a casing mandrel or tire last of cast iron
for holding a casing when making repairs; a tread roller for rolling
down layers of raw stock evenly and quickly; a considerable amount
of binding tape; thermometers; and such motor-driven brushes,
scrapers, etc., as the quantity and quality of the work warrant.

Materials. Each repair shop must carry such a supply of tire-
repairing material as the nature and quantity of its business demands.
Among other things may be mentioned: Tread stock, rebuilding
fabric, single-friction fabric, cushion stock, breaker strips, single-
cure tube stock, combination stock, cement, quick-cure cement,
soapstone, valve bases, valve insides, valve caps, complete valves,
vulcanizing acid, various tube sections, tire tape, cementless patches,
as well as many other tire accessories to sell. Many good tire-repair
shops find a legitimate use for special tire-repairing preparations on
the order of Tire-Doh.

Inner Tube Repairs

In general, all tire repairs come under one or more of the following
headings; puncture; blowouts; partial rim cut or rim cut all around;
and retreading or recovering, and relining.

Simple Patches. Under the heading of punctures are handled
all small holes, cuts, pinched tubes, or minor injuries. Generally,
these can be repaired by putting on a patch by means of cement,
or with cement and acid curing. When well done, this method is
effective. This kind of a job seldom comes to the repair man, and,
when it does, it is principally because the owner is too lazy to do the
work. About the only two cautions necessary are relative to clean-
liness and thoroughness. The tube and patch should be thoroughly
cleaned. Again the patch should be large, well cemented, and the
cement allowed to dry until just sticky enough to adhere properly.
Many a simple patch of this kind has been known to last as long as the
balance of the tube.

Large Patches. Cleaning the Hole. Whenever the hole or
cut is large, it is recommended that the repair be given more serious
attention and vulcanized. The ragged edges of the rubber should
be trimmed smooth with the tube shears or knife, the minimum
amount of rubber being cut away. The hole, however, should be
made large enough to allow the insertion of an inside patch. Then

351

Google

690 GASOLINE AUTOMOBILES

the tube around the hole should be cleaned thoroughly. This is best
done with a cloth wet with gasoline, cleaning not only the outside
but the inside around the hole and at the edges. In order to make a
good job of this, it should be gone over several times; the larger the
hole the more care should be used in cleaning arounH it.

Preparing the Patch. Having the hole well cleaned and ready,
these cleaned parts should be painted with two coats of vulcanizing
cement, which is allowed to dry. This must be thoroughly, not partly,
dry. Then the proper patch is selected, the smaller size being
sufficient for small patches, while in the case of large repairs, the
patch should be from $ to 1 inch larger all around than the hole.
If this is not a prepared patch, one side should be cemented just as
the tube was previously. If a prepared patch is used, the semi-
cured side should be placed in, that is, with the sticky or uncured
side toward the tube from the inside.

When the cement on the patch is just sticky enough, it should be
inserted and the tube pressed down against it all around, slowly
and carefully so as to get good adhesion. Next the cavity about
the inside patch is filled with gum or pure rubber, preferably in sheet
form as it comes for this purpose. This is filled in until the surface
is flush. It is preferable to use a little vulcanizing cement to hold
this rubber in place, particularly if a piece of sheet gum is cut to
fill the hole.

Vulcanizing the Patch. The repair is now about half completed
and is next vulcanized. The length of time, if steam is used, varies
with the amount of steam pressure; if the portable gasoline or alco-
hol type of vulcanizer is applied the time varies with the temperature.
As this time variation is so wide, it is impossible to give an invariable
rule. Thick tubes require a little longer than thin ones, large patches
longer than small ones, wide patches more than narrow, etc. The
vulcanizing must be carefully and thoroughly done, and, as the
success of the whole job depends upon this one process, the arrange-
ment of the tube on the plate, of the soapstone on the new rubber
and on the vulcanizer to prevent adhesion, of the wood or rubber
pad above the patch, of the clamp and its pressure, should all have
careful attention. With 60 pounds steam pressure available, from
10 to 12 minutes is about right, with 75 pounds from 8 to 10 minutes.
Jn any case, the rubber should be cured just firm enough not to show

352

Digitized by

Google

GASOLINE AUTOMOBILES

691

a slight indentation from the point of a lead pencil. This is a good
test to use at first, although after a short experience, the workman
will be able to judge of the condition from the feeling, color, and
general appearance of the patch.

When the size of the plate is small, the tubes should be held up
above it out of the way, partly to allow the full use of the plate
surface, but also to keep the tubes from being damaged.

Inserting New Section. Preparing the Tubes. In case the
damage to the tube is too great to permit the use of a patch, for
instance, in case a blowout makes a wide hole perhaps 7 inches
or more long, in an otherwise good tube, it is advisable to cut out
the damaged section and insert a new section in its place. Some-
times old tubes of the same size can be used for this, but, if not,
sections can be purchased from the larger tire and rubber companies.

fig. 563. Sketch Showing Method of Inserting New Section in Inside Tube

In the repair, proceed as follows: After cutting out the damaged
section, bevel down the ends very carefully, using a mandrel to
work on and a very sharp knife. As the appearance and, to a large
extent, the value of the repair will depend upon these beveled ends,
this should be done in a painstaking manner. Next select the tube
section and cut it to size, that is, from 5 to 6 inches longer than the
section which was cut out and which this patch is replacing. This
allows 2\ to 3 inches for the splice at each end. Bevel the ends of
the tube as well, and, after beveling all four ends, roughen them
with a wire brush or sandpaper.

Making the Splice. Having the tube and repair section beveled
and buffed, the ends to be joined should be coated with one heavy
or two light coats of acid-cure splicing cement. With the tube and
patch properly placed on the mandrels — tube on the male and patch
on the female — turn back the end to be repaired and the end to be

353

Digitized by

Google

692

GASOLINE AUTOMOBILES

Worn Trtad

'Blow-out

applied as shown in Fig. 563. At A is shown the female mandrel
on which is the patch B, turned back from the end of the mandrel
about the right distance, say 3 to 3 J inches. On the male mandrel C
the tube D has been turned back about 7 to 7J inches, then turned
back again on itself about 3 to 3$ inches.

Just as soon as the cement has dried thoroughly on the tube, apply

a coat of acid to the patch and
immediately place the two
mandrel ends together and
snap, blow, or push the end of
the patch over on to the end
of the tube. This frees the
female mandrel, which cap
be laid aside. Immediately
wind the patched portion
(still on the male mandrel)
with strips of muslin or inner
tubing. In 15 to 20 minutes
the cement will have formed
a permanent union, the wrap-
pings can be removed, and
the tube withdrawn through
the slot in the mandrel.

This done successfully,
the whole operation is re-
peated for the other splice.
If the splice does not cure
together well, it indicates
either that the acid supply is
poor or else the splicing was
not done quickly enough
after applying the acid.

Cut

Leaky

K~S

Fig. 564.

Section of Tire, Showing Forma
of Troubles

Outer Shoe, or Casing, Repairs

Classifying Troubles. Some of the common tire troubles —
those of the inner-tube variety just discussed, and casing troubles
as well — can be clearly shown by suitable illustrations. For example,
a section through the tire showing how the troubles occur is some-

354

Digitized by

Google

GASOLINE AUTOMOBILES 693

times very useful, as shown in Fig. 564. Here the pinched tube
and blowout are indicated, the results of these on the inner tube
and also their method of repair having just been described. These
troubles together with punctures, leaky valves, and porous rubber
in the tubes about cover the extent of inner tube troubles. Because
of their more complex construction, casings have more numerous
and more varied troubles, which, consequently, are more difficult
to repair. The more common casing troubles are blisters, blowouts,
rim cuts, and worn tread, the latter indicating the necessity for
retreading. These will be described
in order.

Sand Blisters. The sand blister
shown on the side of the tire, Fig. 564,
is brought about by a small hole, such
as an unfilled puncture hole, in com-
bination with a portion of the tread
coming loose on the casing near this
hole. Particles of sand, road dust,
dirt, etc., enter, or are forced into,
this hole and move along the opening
provided by the loose tread. Soon
this becomes continuous and the
amount of dirt within the break forces
the surface rubber out in the form of a
round knob known as a sand blister.
This is cured by cutting open the
blister with a sharp knife on the side
toward the rim and picking out all
dirt within. When the recess is
thoroughly cleaned, the hole and the
radial hole in the tire tread nearby Fi *f£f bri ^^^
should be filled with some form of In8ido MetEod

self-curing rubber filler, a number of kinds of which are sold. The
double benefit of this is to close the hole so that the trouble is not
repeated and to keep out moisture which would ultimately loosen the
entire tread.

Blowouts. The blowout, which is perhaps the most important
casing repair, may be made in two ways: the inside method, in which

355

* Digitized by

Google

694 GASOLINE AUTOMOBILES

the whole repair is effected on the inside; the combination inside
and outside method.

Inside Repair Methods. Refer back to Fig. 564 for the general
tire construction and to Fig. 565 for this particular case, the inside
of the tire is held open by means of tire hooks and the inside fabric
layers or plies removed for a liberal distance on each side of the
opening. As shown in Fig. 565, a lesser amount of the second layer
should be taken than of the first, and still less of the third and each
subsequent one. On 3£- and 4-inch tires it is not advisable to remove
more than two plies; on 4J-inch tires three, as shown; and on the larger
sizes four plies. The edge of each layer of fabric should be beveled
down thin, as well as the material directly around the blowout.

Outside Method

Apply a coat of vulcanizing cement and when it has dried, say
for an hour, apply another. When this has dried enough to be
sticky or tacky, fill as much of the hole as possible with gum. When
this is filled in level, apply the fabric patch. This is made up to
match the fabric cutout, that is, if three layers are removed, it should
consist of three plies stepped-up to match, and an extra last ply of
bareback fabric unfrictioned on one side. This last layer should
extend 3J to 4 inches beyond the ends of the patch.

When this is properly applied and carefully smoothed down, the
tire is placed in a sectional mold, clamped in place, perhaps wrapped
with muslin strips to hold it tightly against the mold, and heat applied
from the inside. This makes an excellent repair and a fairly quick
and easy one, but it is not applicable for large blowouts; at least, it is
not as effective as the inside and outside method.

Digitized by LiOOQ IC

GASOLINE AUTOMOBILES 695

Inside and Outside Method. In the inside and outside method,
the material is removed from the outside, stepped down, and beveled
in the same manner as for the method just described. Fig. 566 shows
a tire with a medium size blowout, which has been stepped down
for a sectional repair, four plies having been removed. The rule for
the number of plies to remove is about the same as before, except that
in the larger sizes this should depend more on the nature of the injury.
It should be noted, however, that in this case the plies have all been
removed right down to and including the bead. This is done to give
the new fabric a better hold and to make a neater job and one that
will fit the rim better. Give the whole surface two good coats of
vulcanizing cement, allowing it to dry thoroughly.

Apply the same number of plies of building fabric as were
removed, with the addition of chafing strips of light-weight fabric
at the bead. Over this building fabric apply a thin sheet of cushion
gum, slightly wider than the fabric breaker strip; then a thickness
of fabric breaker strip over this; and then over this fabric another
sheet of gum, slightly narrower than the previous sheet. All this,
however, should be built up separately and applied as a unit and
not one at a time, as described. These several plies should be well
rolled together on the table. All edges should be carefully beveled off,
especially the edges of the new gum where it meets the old, as it is
likely to flow a little and leave a thin overlap which will soon pick
loose.

No fabric is removed from the inside, but the hole is cleaned, its
edges beveled, then filled with tread gum, and the inside reinforced
with a small patch of building fabric; over this lay two plies of
building fabric of considerable size. Now the whole casing is placed
in a sectional mold, a surface plate applied to the outside, and heat
applied both inside and outside. This will heat the tire clear through
and make a good thorough job of curing.

Rim-Cut Repair. Partial Cut. To repair a partial rim cut,
one or two plies of the old fabric are removed, unless it is severe,
when three plies may be taken off. This is removed right down
clean as explained under Blowout Repairs, and the cement and new
materials applied in the same way, with the omission of the fabric
breaker strip. However, care should be used to carry all building
fabric layers not only down around the bead to the toe but up on

357

Digitized by

Google

696 GASOLINE AUTOMOBILES

the inside far enough to secure a good hold and ample reinforce-
ment. If this should make the rim portion somewhat more bulky,
remember it was a case of doing this or getting a new tire.

Complete Rim Cut. Where the rim cutting is continuous, the
old side-wall rubber is removed up to the edges of the tread, and
the old chafing strips and one ply of old fabric to about an inch above

the beads removed also.
Cut through the side-
wall rubber all around,
but be very careful not to
cut into the fabric body,
or carcass. The whole
of the side wall and
chafing strips can be
removed in one opera-
tion. Apply two coats
of cement and, after this
is thoroughly dry, put on
a patch consisting of one
ply of building fabric,
one ply of chafing strip,
and a surface, or outside,

Fig. 567. Method of Handling Rim Cuts , . ,

ply of new tread gum.
This is made on the table and the parts thoroughly rolled together.
When completed, vulcanize in a sectional mold with sectional air
bag and bead molds or endless air bag; apply to a split curing-rim
wrap, and vulcanize in heater or kettle. The tire is repaired, but
not vulcanized, and, with the ends of the three applied plies of mate-
rial loosened to show, may be seen in Fig. 567.

Retreading. Retreading is a job which must be done very
carefully, not only because of the job itself, but also because this
is probably the most expensive single job which can be done to a
tire, and the worker should make sure before starting that the wire
warrants this expense. It should have good side walls and bead,
and the fabric should be solid and not broken apart.

Repairing the Carcass. In the usual case, it is advisable to
remove not only the surface rubber and fabric breaker strip, but
also the cushion rubber beneath the breaker strip, that is, the tire

Digitized by VjOOQlC

GASOLINE AUTOMOBILES

697

should be cleaned off right down to the carcass, and the latter cleaned
thoroughly. / As the rubber sticks, a rotary wire brush will be found
useful and quick. However, this should be used carefully so as not to
gouge the carcass. After buffing, the loose particles of rubber should
be removed with a whisk broom or dry piece of muslin. In this
cleaning work the carcass should be kept clean and dry. Apply two
coats of vulcanizing cement and allow both to dry; the first should be
a light coat to soak into the surface fabric; the second should be a
heavy coat.

Building Up the Tread. In building up the tread, it should
not be made, as heavy as the former tread, as the old worn and
weakened carcass cannot carry as heavy a tread as when new.
Furthermore, ft takes longer to vulcanize a heavy tread and presents
more opportunity for failure* In the building-up process, the pro-
portioning of weights is important, and should be taken from the tab-
ulation below, which represents years of experience in tire repairing:

Size of
Case

(in.)

Ply
toward
Fabric

(in.)

Second
Ply
(in.)

Third
Ply

(in.)

Fourth
Ply

(in.)

Fifth t
Ply
(in.)

Last Ply
Over All

Complete

Tread

Consists

♦See Note

3 plies

♦See Note

4 plies

♦See Note

4 plies

♦See Note

4 plies

♦See Note

5 plies

♦See Note

6 plies

♦See Note

6 plies

* Note — Determined by condition of case after buffing and cementing.

Sise of Case
(in.)

Width of Breaker Strip
(in.)

If
21
21

31
4
41

This tread strip is built up on the table with exceeding care,
all edges being rolled down carefully. When the strip has been
prepared and the carcass is ready for it, one end should be centered
on the carcass, and then the balance of the strip applied around the
circumference, being careful to center it all around, as the workman
in Fig. 568 is doing. After it has been applied all around, it should

369

Digitized by

Google

698 GASOLINE AUTOMOBILES

be rolled down carefully, all air pockets opened with a sharp pointed
awl, and the gym at the edges of the plies rolled down with the
corrugated stitcher. When ready, vulcanize in a kettle, using an
endless air bag with tire applied to a split curing-rim, and wrapped —
preferably double wrapped — all around.

Use of Reliner. Many a casing which appears good on the out-
side but which really is unsafe because of fabric breaks on the inside

>orarily prolonged,

t. By this is not

and fabric reliner

a regular built-up

lized in place so as

to be an integral

part of the tire.

For ordinary

breaks, use a

single ply of

building fabric

on a casing

which has been

entirely cleaned

out and which

has had two

coats of vulcan-

izing cement

thoroughly dried

eak, use two plies

fit; the under ply

ides and coated on

Fig. 568. New method of 0ne > and the U PT* T PV S,10llld ** ^Ctioned
Putting on New Tread Qn Qne s ; de ^^ ^ s J de toward t he tube being

bareback. Use an endless air bag for internal pressure, apply to a
split rim, wrap, and vulcanize in a kettle from 35 to 45 minutes at
a steam pressure of 40 pounds.

Summary. By the application of parts of the foregoing instruc-
tions and the use of much common sense, coupled with a knowledge
of the construction, use, and abuses of tires, the repair man will be
able to handle any form of tire repair brought to him. In starting

360

Digitized by

Google

GASOLINE AUTOMOBILES 699

out, perhaps he could not do a better thing than to take an old tire
apart to see just how it is constructed. This will give a much more
clear idea than any number of diagrams, sketches, or photographs.

The tire repair man should remember, too, that this is no longer
a game, but that, by means of scientific apparatus and the appli-
cation of correct principles, it has been brought up to a high state
of perfection; an expert can predict with reasonable accuracy what
will happen in such and such a case, if this and that are not done.
In short, the tire-repairing business within the last few years has
been brought up to a stage where it, or any part of it, is a dependable
operation. The tire repair man should handle all his work from
this advanced point of view; it will pay the largest dividends in
the long run.

SUMMARY OF INSTRUCTIONS

Q. What are the units comprising the final-drive group?

A. Universal joints; driving shaft; final gear reduction; axle-
shaft differential; axle enclosure; torque rod, or tube, or substitute
tor this: radius rod, or tube, or substitute for this; brakes; wheels; and
tires.

Q. Why are these called the final-drive group?

A. Because they constitute the final drive of the car, beyond the
power-producing unit, the engine; the connecting and disconnecting
unit, the clutch; and the speed-changing unit, the transmission.

Q. What is the function of the universal joint?

A. In the final-drive group, it is used to transmit power at an
angle, as, from a horizontal-transmission shaft to an inclined-driving
shaft.

Q. How does it do this?

A. The construction is such that the driving shaft is attached
to one set of pins, while the driven shaft is attached to another, the
axes of these intersecting in a common point. As the driven shaft can
turn about its pins in one plane and, with the complete joint, about the
driving shaft pins in another, as well as combinations of the two,
complete freedom, or universal movement, is assured.

Q. What are the power losses in a universal?

A. In a well-designed and fitted universal joint, working prac-
tically at zero angle, there is no loss, but as the angle increases, the loss
increases until at about 20 degrees, it may reach 2 or 3 Der cent.

361

Digitized by

Google

700 GASOLINE AUTOMOBILES

Q. Why is such a joint needed?

A. The final drive must be at the center of the rear axle, which
is comparatively low, say 17 inches with 34-inch wheels or 18 inches
with 36-inch wheels, while the power must originate at the engine
which cannot be set as low as this, that is, the power must be gen-
erated at a higher level than that at which it is used. An inclined
shaft and universal joints must be used somewhere in the system.

Q. What other considerations necessitate universal joints?

A. The engine level varies little, while the rear end of the chassis
varies up and down through a considerable range. In addition, the
rear end carries perhaps 85 per cent of the load and sustains greater
road shocks because of this fact. The design is such as to keep the
front, or engine, end as quiet and as nearly stationary as is possible.
These considerations necessitate a flexible connection between the two
ends, so that one can move frequently and through considerable
distances, while the other moves seldom and through very small
distances. In addition, the rear end must sustain considerable side
sway, so that freedom in a sidewise direction is necessary. The only
way in which these necessities can be obtained is through the use of
universal joints.

Q. What is a slip joint?

A. One which will allow sliding, or slipping, of one part or shaft
within the other. Thus, under certain restraining conditions the rise
and fall of the rear end may mean approaching or receding of that end
to and from the front portion. With a slip joint, this is made easy.

Q. What is the usual form of a slip joint?

A. Generally, this takes the form of a squared shaft within a
squared-out housing, although sometimes the square is rounded off
to give a slight universal action.

Q. What is the modern form of universal joint?

A. A thin flexible disc of steel, leather, fiber, or laminated fabric,
with the driving shafts bolted to two opposite points and the drive
shaft bolted to two others between them has been found to be much
simpler, lighter, cheaper, and better than the average universal,
although it allows only limited angular motion. The engine is being
gradually lowered, while the rear wheels are constantly being
increased in size; so the difference of level is not as great as it was, and
there is less need for the full universal.

3«2

Digitized by

Google

GASOLINE AUTOMOBILES 701

Q. What is the biggest advantage of these to the repair man?

A. They allow the removal of a driving shaft, or a unit on either
side of such a joint much more quickly and easily, with less work,
than any other form, similarly, in replacement after the repair is
completed. In addition, they have no loose parts to be lost or mis-
laid with consequent trouble and delay of the work.

DRIVINQ SHAFTS

Q. What is the usual type of driving shaft?

A. The usual driving shaft is of small diameter and solid.
Cold rolled steel is used on the lower priced cars, but forged steel
machined at the ends (at least) is used on the better cars. On many
of the most expensive machines, the shaft is fairly intricate in shape
and is machined all over after forging, sometimes ground after har-
dening.

Q. What would be the advantage of a spring shaft?

A. Being flexible, it would cushion the shocks so that none of
these reached the engine. Such shocks as are induced by jerking
the throttle wide open, or stepping on the accelerator pedal suddenly
or, on the other hand, a sudden application of the brakes.

Q. What is its real disadvantage?

A. Being small, the owner of the car and the driver would
always mistrust it, and would not feel free to drive as they would with
a larger and more dependable shaft.

Torque and Radius Rods
Q. What is torque?

A. Torque is turning effort, or force, applied to rotation, in the
case of an automobile, to rotation of the driving shaft, and from it to
the rear axle and wheels by means of the final reduction gears.

Q. What is a torque rod?

A. A rod, bar, or tube, provided to take, not the torque, but the
equal opposite reaction from the torque application to the final drive.

Q. What is the manifestation of this torque reaction?

A. A tendency of the driving shaft and driving bevel gear to
rotate up and around the bevel-driven gear in a counter-clockwise
direction.

Q. How does the torque rod absorb this?

A. By extending this forward and attaching it to a frame cross-

363

Digitized by

Google

702 GASOLINE AUTOMOBILES

member at the front end and to the rear axle housing at the rear end,
this counter-clockwise motion of the driving shaft is prevented.

Q. What is driving effort?

A. The force applied to the rear wheels tending to move the
car forward. It is transmitted to the car, or frame of the car, as
a push.

Q. How is this push transmitted to the frame?

A. In one of three ways; through special radius rods which
transmit it directly to the frame; through a central tube which handles
both torque and driving effort, transmitting this first to a frame cross-
member, then to the main side members and through the springs,
which are modified in attachment so as to take care of these extra
stresses.

Q. Which is the best form?

A. The use of radius rods, one on each side, transmitting the
stresses directly to the frame, is undoubtedly the best form, but also
the most expensive, the heaviest, and includes the greatest number of
parts.

Q. Which is the most simple form?

A. The use of the springs, the so-called Hotchkiss drive, but this
also reduces the easy-riding qualities of the car because the springs,
which should be flexible for easy riding, must be made somewhat
rigid in order to transmit torque and driving reactions.

Q. Which is the cheapest?

A, Undoubtedly the use of the springs is the cheapest form, as
it eliminates all additional parts, and simply necessitates a pivoted
form of springing end in place of the usual shackle there.

FINAL DRIVES

Q. What are the usual methods of final drive?

A. Final drive is usually by one of these methods: roller chain,
silent chain, spur gear, bevel gear, spiral bevel gear, worm and gear,
rollers.

Q. Are all of these in use today?

A, All but the roller, although the two forms of chain drive
have almost gone out of use for pleasure cars and are becoming less
popular even for truck use.

Q. Which is most popular?

364

Digitized by VjOOQlC

GASOLINE AUTOMOBILES 703

A. For pleasure-car use, the spiral bevel form, and for motor
trucks, the worm.

Q. Why is the spiral bevel popular on pleasure cars?

A. Because of its many advantages. It is just as simple as the
straight bevel, needs no additional parts, is more quiet, perhaps more
efficient, is less likely to cut or wear, can be removed as readily, and
has other minor advantages.

Q. Why is the worm popular for trucks?

A. It has all the needed qualities; it is efficient, silent, easy to
handle, and allows bigger gear reductions than any other form.
Furthermore, various gear reductions are interchangeable by changing
other parts, and the worm has other advantages.

Q. Why is the worm not used more on pleasure cars?

A. Because it is not so well adapted to high speeds of 50 to 60
miles an hour and higher, which may be demanded, and because the
large reduction between engine and rear axle, which is its biggest
advantage, is not needed on pleasure cars.

Q. What are the three mostly used forms of rear axle?

A. The full floating, semi-floating, and three-quarter floating.

Q. Which is the best form?

A. From an engineering standpoint, the full floating is undoubt-
edly the best, but it is also the most complicated, with the largest
number of parts, and the most expensive to construct.

Q. Which is the most simple form?

A. The semi-floating form is the most simple, but it lacks
advantages which the majority of car owners want. It is the cheapest
to make, but is made so through the lack of these advantages.

Q. Which is the compromise form?

A. The three-quarter floating form seems to offer a maximum
number of advantages with the minimum of disadvantages. It has
practically all the advantages of the full floating with less cost. It
has all the advantages which the semi-floating lacks and costs but
little more.

Q. Which is the most popular form?

A. The floating still has the greatest number of makers, but the
three-quarter form is rapidly gaining in popularity and, in another
year, will displace the full floating as the most popular, both as to
the number of makers and as to the actual number of cars.

365

Digitized by

Google

704 GASOLINE AUTOMOBILES

Q. Describe the internal-gear axle?

A. In this form a spur gear is used to drive an internal gear of
larger diameter. This construction enables the separation of load
carrying and power transmitting, so that one part of the axle can
handle each.

Q. For what is this used mostly?

A. The internal-gear axle is used mainly on motor trucks,
although a few heavy pleasure cars have been built with it.

Q. What is a differential?

A. A mechanical device for allowing the rear wheels to travel
different distances when turning a curve or corner.

Q. How is this done?

A. By combinations, or nests, of gears and a divided rear axle,
one-half being fixed to each half of the differential, with only the nests
of gears connecting the two. As these are free to revolve as a unit,
or stand still and have their gears revolve, the drive can either be
transmitted all to one wheel, half to each wheel, or divided unequally.

Q. What is the usual differential form?

A. The usual differential gear is constructed with bevel or
spur gears, the bevel form being more popular, the spur cheaper.

Q. What is undesirable in present differentials?

A. Present differentials have the disadvantage that they work
for resistance not distance. This permits the wheel, which we do not
want to slip, to slip on icy places so that the car cannot pull itself free,
the differential making a bad matter worse.

Q. If the differential worked correctly, how could this be?

A. In such a case, since the differential worked only for differ-
ence in distance, and there was no difference in distance on an icy
place, the power would be transmitted equally to the rear wheels.
One would slip, but the other on firm ground would use its share of
the power to pull the car off the icy place.

Q. How is it expected that this result will be attained?

A. By the use of helical gears, which, like the worm of a steering
gear, are not reversible but will transmit power only in one direction.

Q. In addition to correct differentiation, what is it expected
these differentials will do?

A. Eliminate skidding, always dangerous and always a possi-
bility with present forms. The connection between skidding and

366

Digitized by VjOOQlC

GASOLINE AUTOMOBILES 705

present differentials has never been explained, but can be readily
proved by the simple process of building a car without a differential.

Q. What forms of bearings are used in rear axles?

A. All the different kinds of bearings are used in rear axles:
plain ball, plain straight solid roller, straight flexible roller, tapered
roller, a few plain bronze bearings, ball-thrust forms, and others.

Q. Which form is most popular?

A. There is little choice between the two forms of roller and the
ball bearing. In fact, the majority of axles use several different forms
of bearings; so it is difficult to compare the work of the various bearing
types.

Q. How can a broken spring clip be repaired?

A. A good substitute for a spring clip can be made from two
flat plates and four bolts to reach from one plate to the other. The
purpose of the spring clip is to hold the spring to the axle; this combi-
nation will do the same thing.

Q. How would you line up a rear axle?

A. With a try-square and plumb bob, working downward from
the main frame, determine the distance from the rear end of the frame
to the back side of the rear axle, on each side of the car. If the two
do not agree exactly, the axle is out of square by the difference, or by
half this difference on each side. Loosen the spring bolts, set the axle
correctly, tighten the bolts, and check up the measurements again.

BRAKES

Q. What are the two general types of brakes?

A. The contracting-band, which is an external brake, and the
internal-expanding shoe.

Q. How are these used?

A. There is no set rule; some designers use only the internal-
expanding form, claiming this is more powerful and dependable;
others use only the band, claiming this is cheaper to make and repair
and just as good; still others take no side but use both forms.

Q. Has there ever been any agreement in relation to brakes?

A. Up to about a year ago, it was general practice to use the
internal-expanding shoe brake for the emergency, or hand, brake.
This was the case whether the band form was used for the foot, or
running brake, or another expanding shoe.

367

Google

706 GASOLINE AUTOMOBILES

Q. Does this rule hold now?

A. No. Many hand-operated brakes are of the contracting-
band form, while many foot-operated forms, which would be consid-
ered the service, or running, brakes, are internal expanding. The
tendency toward unit power plants is bringing back a shaft brake of
the band type, operated by the hand lever.

Q. Where are the brakes generally located?

A. Except for the tendency just mentioned, the brakes have
been located as much as possible in the rear wheels, on the assumption
that this gave the most direct and thus the best application of the
braking force.

Q. How are brakes arranged on the rear wheels?

A. When both brakes are placed on the rear wheels, practice is
sharply divided into two camps. The one places the running brakes
as a band form on the outside of the drum, claiming this makes
a smaller lighter drum, a more compact group on the wheel, and less
expensive because the drum is cheaper. The other places the two
brakes side by side, making both of the internal-expanding shoe form
inside a wide drum, claiming this is more effective, more powerful,
and that the brakes are better protected against dirt, dust, and water
because entirely enclosed, and thus are more effective and need less
attention.

Q. What is the electric brake?

A. A new device which substitutes the rotation of an electric
motor for hand or foot application of the brakes. This is put into
action by a finger lever on the steering post, which makes contact,
through suitable resistance, between the battery and the motor. When
the motor rotates a cable is wound up and this pulls the brakes.

Q. Is this a powerful form?

A. Not only yery powerful but also very quick to act, so that
care must be used in applying it.

Q. What is the hydraulic brake?

A. A new form for heavy trucks and tractors, in which the use
of an oil, which transmits power equally and without loss, is substi-
tuted for the usual rods and levers in the application of the brake.
The construction is such that the driver can apply the brakes by a
stroke of the hand lever, and if this does not give sufficient power to
stop the truck, he can let the lever go forward and then pull it back-

36g Digitized by VjjOOQIC

GASOLINE AUTOMOBILES 707

ward again; this action soes not release the brakes but does apply
more force, that is, it can be worked continuously until sufficient
power is applied to stop the vehicle, a peculiarity of this particular
form.

Q. What is the vacuum brake?

A. A new form which utilizes the suction of the engine to create
a vacuum in a special braking cylinder, the movement of a piston in
which applies the brake. The amount of action depends on the
amount of suction, that is, regulated by the amount the valve is
opened, and this is dependent upon the pressure applied to the finger
lever or toe button, whichever is used.

WHEELS

Q. What are the usual forms of pleasure-car wheels?

A. The plain wood form and the wire wheel comprise 99 per
cent of all pleasure-car wheels; the wood forms about three-quarters
and the wire about one-quarter of the total.

Q. What are the tendencies in wheel sizes?

A. On small cars the tendency is toward larger and larger sizes,
but on the larger heavier cars the tendency is away from the very large
sizes of a few years ago. The latter tendency has been brought about
by the standardization of tire sizes, and the elimination of 38s, 40s,
and larger sizes formerly made.

Q. What are the different forms of wire wheels?

A. The double-spoke form, which is lacking in lateral strength;
the triple-spoke; and the quadruple-spoke. The two latter make up
in strength what the former double-spoke form lacked. Except for
number of spokes, these do not look any different to the casual
observer.

Q. What is the sheet-steel wheel?

A. A form in which the whole wheel construction consists of a
pair of sheet-steel members. These are given a slight taper, some-
times have holes through them for ventilation and to make them
lighter, and frequently are painted to resemble wood-spoke wheels.
The steel sheets are made thin enough to be flexible.

Q. What is the pressed-steel wheel?

A. A newer form in which a simulation of one-half the entire
wheel spokes, hub and all, is pressed out of thin sheet steel, and a pair

369

?08 GASOLINE AUTOMOBILES

of these welded together so that the finished product has all the
appearance of a wood wheel with the usual number of spokes, but
without the rim which this construction eliminates.

Q. What are the usual truck wheel forms?

A. Most truck wheels are of heavy wood or cast steel. The
latter do not weigh a great deal more than the former; because oi the
greater strength of the material, less of it can be used.

Q. Which is the most popular?

A. The wood form is still the most popular, despite its disad-
vantages for heavy truck use, but the steel form is gaining rapidly?

Q. What are the advantages of steel?

A. Greater strength, particularly to resist side stresses; better
ventilation and removal of heat from the tires; more firm foundation
for the tire so that it holds its shape better; and longer life at less cost.

Tires

Q. What are the general divisions of all tires?

A. Pneumatic, cushion, and solid.

Q. What is the principle of each?

A. The pneumatic tire has an interior air bag which is pumped
full of air, the tire gaining its resiliency from this. The cushion tire
is so constructed as to have a central air passage or other yielding
space so that it gives a cushion effect under loads. The solid tire is a
solid mass of rubber, its only give being the natural yield of the rubber.

Q. Is there a distinct field for each?

A. Yes. Pneumatics are used only on pleasure cars and the
lighter trucks or delivery wagons; cushion tires are used mostly on
slow-speed electric pleasure cars and a few light trucks; solid tires are
used only on the heavy trucks.

Q. What is the big disadvantage of the pneumatic form?

A. Its liability to puncture or blow oilt, or loose its air other-
wise, after which the tire is useless until the fault is mended; in fact,
the tires are actually in the way, and running a deflated tire only cuts
it to pieces.

Q. What are the divisions of pneumatic tires according to shape
and method of holding?

A. While there are other forms, practically all tires today are in
one of two classes, the clincher or the straight side.

370 Digitized by GOQQle

GASOLINE AUTOMOBILES 709

Q. Describe the clincher type?

A. This is made with a bead or hard portion at the base, which
forms a projection around which the clincher rim fits. The rim has
the shape of a flattened U with the ends curled in, and the beads on
the tire fit into these curled ends or clinches.

Q. What is the advantage of this?

A. The clincher form is held firmly on the rim, while the stiffness
of the bead contributes more rigidity of form and permanence of
shape to the whole tire.

Q. Describe the straight-side form.

A. This type of tire has no bead, the fabric forming the side
walls being carried straight down to form the base without additional
thickness of material.

Q. What are the advantages of this?

A. Its simplicity and lighter weight, with greater air space are
the advantages of the straight-side form. In addition, in the newly
standardized rim forms, the form of rim adapted to the straight-side
tire is more simple, lighter in weight, and lower in cost than any other.
It has been found by experience that the holding power of the beads
was unnecessary as the inflated tire could not come off the wheel
whether it had a bead or not, since its diameter at the base could not
be increased in any possible way sufficiently to pass over the larger
size rim.

Q. What is an oversize tire?

A. In the standardization of tires and rims, for each even tire
size, which is called a standard, there is an oversize made which will fit
on the same rim without any other changes.

Q. What is the difference between standard and oversize tires?

A. All standard tires are made in even inches of outside diam-
eter, and all oversize tires are made in odd inches of outside diameter,
so that the rule for oversizes is this: An oversize is one inch larger in
diameter and J inch larger in cross-section, that is, the Ford size
is 30 by 3J, the oversize for this, according to the rule, is 31 by 4; an
average large car size is 36 by 4J, the oversize for this is 37 by 5.

Rims

Q. What are the general different rim forms?

A. Rims are generally divided into these forms: plain, which is

371

Digitized by

Google

710 GASOLINE AUTOMOBILES

no longer used; clincher, which is gradually going out; quick-detach-
able in its various forms; and demountable rims, now almost universal.

Q. What are the differences in these?

A. The clincher rim is a solid form, and the tire has to be
stretched to get it on or off the rim. For this reason, it has to be made
with a more or less yielding base, but even at that, tire removal is
very difficult. The quick-detachable form is made with a locking
ring on one side to replace the solid side of the clincher, so that tires
can be applied easily. The demountable rim is a form which is used
in combination with the others, this being a modification of the felloe
of the wheel by which the entire tire and rim are removed in case of
trouble, and then are replaced by another tire and rim which have
been carried for this form.

Q. What are the advantages of this?

A. All roadside work is eliminated. When a puncture or
blowout occurs, the driver simply jacks up his wheel, takes off tire
and rim, and puts on the square tire and rim — the tire being inflated —
lets down his car by means of the jack and drives off. The worn, or
damaged tire, is carried at the rear in place of the spare, and is mended
in the convenience and comfort of the garage or left at a tire repair
station for that purpose. It saves work, time, and trouble at a time
when these are of the greatest value to the owner. Given demount-
able rims, supplied on the car by the manufacturer, the car can be
operated with all these conveniences without extra tire expense.

Q. How are demountable rims held in place on the wheels?

A. Nearly all demountables are held by means of wedges, with
separate bolts to press these into place, or else a construction in which
the bolt and wedge are combined.

TIRE REPAIRS

Q. What is vulcanization?

A. Vulcanization is the curing, or cooking, of raw rubber. By
this curing it is more suitable for hard usage and its soft pliable
character is changed without injuring its resiliency. If these were
unchanged the tire would cut and would not wear.

Q. How is this accomplished?

A. By the application of heat in moderate quantities and in dry
form. The heat is not applied directly but through metal. In the

372

Digitized by

Google

GASOLINE AUTOMOBILES 711

usual tire-curing mold the central space for the tire is surrounded by
metal, with a hollow annular space outside of this into which the
steam, which is generally used', is introduced. The heat from this
steam penetrates the metal inside and vulcanizes the tire.

Q. Are all vulcanizers operated by steam?

A. Practically all the larger ones are, but many of the smaller
forms of the portable type burn gasoline in the heating space, others
use electric resistance coils.

Q. What is the advantage to the private owner of a vulcanizer?

A. When a tire is cut badly, he can apply raw rubber as a patch
or repair, and then vulcanize this for the double purpose of curing
and of uniting it with the older part of the tire. In this way, tire life
is much prolonged at little expense.

Q. Is vulcanization profitable as a business for a repair shop?

A. It is said to be highly profitable, after suitable equipment
has been purchased and a trade built up. It is said to be a more
steady and stable business than any other, for, as soon as an owner has
been convinced of the value of vulcanization of tubes and casings, he
will bring in all his tire repairs.

Q. What is a sand blister?

A. A small opening in a casing, into which sand has entered and
continues to enter until the outer surface is swelle4 up just like a
blister. If neglected, this will ruin the casing.

Q. How should a sand blister be cared for?

A. By the immediate removal of the sand and the cleaning of
the cavity, after which it should be filled with a tire-repairing cement
or tire-filling compound. The sand can be removed by cutting a small
hole in the underside of the blister with a sharp penknife.

373

Digitized by

Google

M
O

Q
O

85 -»
0.°

2 »

3 t

oo <

O 5

M
»

Digitized by

Google

ELECTRICAL EQUIPMENT FOR
GASOLINE CARS

PART I

INTRODUCTION

Importance of Electricity on Automobiles. Starting with
nothing more than a few dry cells and a wiring system that would
have shamed an itinerant bellhanger, the electrical equipment of
the automobile has constantly increased in importance, until within
the last few years it has become the most essential auxiliary there
is on the machine. Electricity now starts the motor, ignites the
charge in the cylinders,. lights the car and the road ahead, sounds
the horn, and in some instances shifts the gears and applies the
brakes. In addition to performing the numerous functions already
mentioned, it has even gone as far as to displace the flywheel, clutch,
and gearset altogether, in which case the car is provided with as
many gradations of speed as a steam car. It seems quite likely that
along this line is to be one of the most important developments of
the next few years.

Inherent Weakness of Electrical Devices. Even in the present
highly perfected state, the electrical equipment still constitutes the
weakest element among the motor auxiliaries. In fact, it is subject
to more frequent defection than any other single element of the
entire construction of the automobile. This must not be taken as
implying that it is defective in any sense, as it is quite the contrary,
ignition, lighting, and self-starting systems having been developed
to a degree of reliability that was undreamed of in the earlier days.
But owing to its nature, the electrical equipment is more susceptible
to derangement. Consequently, a rather substantial proportion
of the minor troubles of automobile operation that still survive to
harass the motorist arise from some failure of the electrical system.
Of course, many of these are due to the inexperience or ignorance
of the motorist himself, and for this reason it behooves the student

375

Google

2 ELECTRICAL EQUIPMENT

to give more than the usual amount of attention and study to this
branch of the subject.

ELEMENTARY ELECTRICAL PRINCIPLES

Knowledge of Principles Necessary. To acquire a good
practical working knowledge of electricity as applied to the auto-
mobile today, it is essential not merely to find out how things are
done, either by watching the other fellow do them, or by studying
"pictures in a book", but also to learn why certain things are done
and why they are carried out in just such a way. In other w r ords,
the man whose knowledge is based upon theory and principles
applies knowingly the cause to produce the effect and is certain
that the desired effect will be produced. On the other hand, the
man who works only with his hands aimlessly goes from one thing
to another trusting chiefly to luck to accomplish two things. One
of these is to strike upon the remedy for the trouble the cause of
which is sought, and the other is to deceive the spectator — usually
the owner of the car — into believing that the fumbler really knows
what he is about.

There are accordingly two distinct classes of knowledge as
regards the electrical equipment of an automobile — one w T hich is
picked up by rote, an isolated point at a time, and applied in the
same manner, and the other which is based upon a clear insight
into the underlying reasons for the various actions and reactions
that make up the different electrical phenomena involved. If
we w r ant to know what is wrong with an electric motor, it is essential
that we should know what makes an electric motor operate when
everything is right. In the same way, it would be groping in the
dark to attempt to investigate the reasons for the failure of a dynamo
to generate current, or a storage battery to give up its charge,
if we had no knowledge of why a dynamo, when run by an outside
source of energy, normally produces a current, or why an accumu-
lator literally "gives back" what has been put into it when its
circuit is closed after charging.

It will accordingly be the function of this introductory chapter
to give a brief r£sum6 of the principles underlying the operation
of what has come to be the most important auxiliary of the gasoline
motor as applied to the automobile — its electrical equipment.

376

Google

ELECTRICAL EQUIPMENT 3

A thorough understanding of these principles will go a long way
toward enabling one to remedy the various minor ills that afflict
the apparatus, and to recognize at once those of a nature serious
enough to be beyond the first aid which even the best equipped
garage is capable of giving. It is worse than a waste of time to
hunt for a short circuit or a ground as the cause of failure of the
dynamo to generate, when an inspection of its parts reveals the
fact that its armature winding has been burned out. Again, one
can hardly expect the motor to continue starting the gasoline engine
when the owner's neglect of the storage battery has permitted the
plates to sulphate so badly that they are practically worthless.
Contempt of "book knowledge" is not wholly a thing of the past,
and many men consider themselves "practical" in insisting upon
learning how to do things with their hands alone. The best-paid
man, however, and he who can instruct others how things should
be done, is the man who uses his head to acquire a knowledge of
the theory upon which practice is based, and then employs his
hands to much better effect by letting his brain guide them.

THE ELECTRIC CIRCUIT

Current. Just what electricity is we do not know — maybe
we never shall know — but it is a matter of common knowledge that
it is one of nature's prime forces and as such is universal. The
air, the earth, the water, the clouds, our bodies and those of animals,
and other inanimate objects such as trees, houses, and the like
are all electrified to a greater or less degree all the time. The
amount of electricity that any given object possesses at a given
moment depends upon its capacity (the electrical meaning of which
is given later) and the conditions of surrounding objects. For
example, a room will hold a certain amount of air; if it is unin-
fluenced by other conditions, we know that the room is full of air
at an approximate atmospheric pressure of 15 pounds to the square
inch (the usual pressure at sea level). The room may be considered
in a normal "state of charge".

There is nothing that differentiates the air in this room from
that of the room adjoining. It is perfectly quiet and nothing is
disturbing it; there is no tendency for it to move. If, however,
all the openings of the room are tightly closed with the exception

ST* Digitized by

Google

4 ELECTRICAL EQUIPMENT

of a duct for the admission of more air under the impulse of a power-
ful compressor, in a very short time there will be a marked difference
between the air in this room and the air in the other rooms. Instead
of the normal atmospheric pressure of 15 pounds per square inch,
there will be a pressure against all parts of the room — floor, walls,
and ceiling — of 50, 60, or 100 pounds, according to the length of
time the compressor has been working and the degree of tightness
with which the various openings have been closed. Thus there
will be a great deal more air in the one room than in its neighbors.
If it were electricity instead of air, the room would be said to be
highly charged.

The air in this room, on account of the pressure which it is
under, is constantly seeking an outlet, and it will gradually leak
out through various small openings, probably without its escape
being noticed. The same conditions obtain when a body becomes
electrified beyond its capacity to hold a charge — the charge of
electricity will leak away without giving any indication of its passing.
Turning again to the room containing the compressed air, if a door
or window of that room is opened suddenly, the pressure is immedi-
ately released through that opening and anyone standing in front
of it would say that a strong current of air blew out. In the case
of electricity, if any easy path of escape is provided, the entire
charge will rush away from the body, and there is then said to be
a current of electricity "flowing" from this point of escape to what-
ever other object equalizes the pressure by becoming charged.
An electric current is accordingly electricity in motion; it is simply
said to flow. But to cause it to do so there must be pressure. The
electrical term for this pressure is potential or voltage.

Electrical Pressure. Every day in the year the earth transmits
a greater or less proportion of its electrical charge to the atmos-
phere, or receives a charge from the latter, but unless the conditions
are favorable there is no visible indication of this difference of
potential as it is termed. It must be borne in mind that this differ-
ence of potential, or difference in electrical pressure, between two
points is what causes a current to flow. Given a hot day in summer,
however, when the air is heavily charged with moisture and low
cumuli, or rain-charged clouds form in great masses, then the
electrical charges from the earth and the air accumulate in these

378 Digitized by GOQQle

ELECTRICAL EQUIPMENT 5

great banks of dense water vapor instead of passing up to the higher
regions of the atmosphere. When the charge exceeds the capacity
of the clouds, and the electrical pressure, or difference of potential,
between two neighboring clouds or between a cloud and the earth
becomes very great, we havethe familiar phenomenon of lightning,
the electricity escaping in a several-mile-long flash instead of by
means of the little spark with its snap as it passes from one object
to another under similar conditions.

Resistance. It is thus apparent that electricity is an element
that can be expressed as a quantity, and likewise one that can be
subjected to pressure. The unit of quantity is the coulomb; the
unit of electrical pressure is the volt; the unit of current is the
ampere, equal to one coulomb per second. Resuming the simile
previously given, 500 cubic feet of air per minute forced into a
room under 100 pounds pressure may be likened to a current of
500 amperes at 100 volts. And, just as the opening allowed deter-
mines the rate at which air will escape, so the electrical outlet
influences in the same manner the current that will flow. From
this it is evident that there is another factor to be considered.
This is resistance.

If a half-inch hole is bored in the door of the room, the air
will escape at a pressure of 100 pounds to the square inch, but
only a few cubic feet per minute can pass through the orifice. If
a very fine wire is used to tap the given charge of 500 amperes
at 100 volts, the current will have a potential of 100 volts, but very
few amperes will pass through the fine wire. If the pressure back
of the air is increased, however, more air will be forced through
the small opening in the same time; and if there is a greater potential
back of the electrical current, more current will be passed through
> the fine wire. Thus the factors of electrical quantity, pressure,
and flow are all related and are all dependent on the factor of
resistance. The unit of resistance is the ohm.

Ohm's Law. From this interrelation has been deduced what

P
is known as Ohm's law, usually expressed as I =-^, or current equals

voltage divided by, resistance, E denoting the electromotive force,
which is only another term for voltage or potential — the electrical
moving force back of the current I.

37ft

Google

6 ELECTRICAL EQUIPMENT

As a practical application of the preceding formula, take the
case of a small conductor connecting the battery and starting
motor of the electrical starting system on an automobile. The
diameter of the wire is such that the length required to connect
the two points has a resistance of 10 ohms. One ampere is that
amount of current which will pass through a conductor having
a resistance of one ohm under a pressure of one volt. The starting
system in question operates at 6 volts. Hence, I=iV = .6, that
is, the battery would be able to force only .6 ampere through that
small wire, and the starting motor would not operate.

It is apparent from the foregoing that the formula for Ohm's
law may be transposed to find any one of the three factors that
may be unknown. For example, given the conditions just men-
tioned, we may determine how much resistance the wire in question
has. The resistance equals the voltage divided by the current:

that is, R = —, or resistance equals — = 10 ohms. Or again, if it is

desired to learn what voltage is necessary to send a current of .6
ampere through a resistance of 10 ohms, the solution calls for an
equally simple transposition of the formula. Given any two factors,
then the third may be readily determined.

Ohm's law is absolutely fundamental in all things pertaining
to electrical operation, and the man who wants to make his knowledge
of the greatest practical use will do well to familiarize himself with
it. Naturally it does not enter into repair work to more than a
small fraction of the extent that it enters into the design of motors,
generators, and other electrical devices, but a knowledge of it is
of distinct value.

Power Unit. To go back to the simile of air under pressure,
it is apparent that the energy released by the lowering of this
pressure may be made to perform useful work, such as driving a
compressed-air drill, running a small air motor, or the like. So
with the electric circuit, the drop from a higher to a lower potential,
which causes a current to flow, is a source of power. Electrical
power is the product of the amperage or current multiplied by the
voltage at which it is, applied. The power unit is the watt and it
is equivalent to one ampere of current flowing under a pressure,
or potential, of one volt. There are 746 watts in a horsepower.

380

Digitized by VjjOOQIC

ELECTRICAL EQUIPMENT 7

Electrical computations, however, are based on the metric system
to a large extent, so that instead of being figured in horsepower,
electrical energy is figured by the kilowatt, or a unit containing
one thousand watts, and the charge therefor is based upon the length
of time for which this amount of energy is employed. From this
comes the now familiar expression "kilowatt-hour".

The power equivalent is expressed as P = IxE, current multi-
plied by electromotive force (potential), and, as in the case of Ohm's
law, with any two of the factors given, the third may be readily
determined. For example: How much power is developed by
a 6-volt starting motor if 125 amperes of current are necessary
to turn the automobile engine over fast enough to start it? The
amount of current given is an arbitrary average taken simply fo*
the purpose of illustration, for in overcoming the inertia of an
automobile engine a great deal of current is required at first, the
drain on the battery often exceeding 250 amperes for a few seconds,
then dropping as the engine turns over to about 50 or 60 amperes.
Taking 125 as the average, we have 125X6 = 750 watts = .75 kilo-
watt, or slightly over one horsepower.

Granting that one horsepower is necessary to turn over a

3^ by 4-inch six-cylinder motor at 75 r.p.m. — a speed that has been

predetermined as necessary to cause it to take up its own cycle

under the most adverse starting conditions — and given a 6-cell

storage battery capable of developing a potential of 12 volts, then

P 746

we have : 7 = — , or current = — =62.1+ amperes, which represent
ht 12

the average demand upon the storage battery to start that engine

under normal conditions. This illustration and the previous one

show the working of Ohm's law; doubling the voltage halves the

amount of current necessary. As the life of a storage battery is

largely determined by the rapidity as well as by the number of

its discharges, and as the storage battery is the weakest element

in any electric lighting-and-starting system, it may well be asked

why the 12-volt standard is not universally adopted, or why, as

is done in some cases, a 24- volt battery is not employed and the

current consumption again reduced by half. Just why this is not

done is explained in detail in the section on the voltages employed

in electric starters generally.

381

8 ELECTRICAL EQUIPMENT

Conductors. To lead steam or air under pressure from a
boiler or compressed-air reservoir to the point at which it is to be
utilized as energy, it is desirable to use a conductor that will not
waste too much of this energy in useless friction. That is, the
conductor must be of ample size in proportion to the volume to
be conveyed, smooth in bore, and free from sharp turns or bends.
The transmission of electrical energy involves some of the same
factors. While neither the smoothness of the bore nor the presence
of bends and turns has any effect, they have their counterpart
in the conductivity of the material of which the wire is made, the
size of the wire in proportion to the amount of current to be carried
being also a matter of prime importance.

Resistance of Materials. Materials differ greatly in their
ability to conduct an electric current, or, to put it the other way
around, they differ in the amount of resistance that they offer to
the passage of the current. Silver in its pure state heads the list
in the table of relative conductivities, and it is accordingly said
to possess a relative resistance of one, or unity; the resistance of
every other material may be expressed by a number which repre-
sents the resistance of that particular substance as compared with
pure silver. Naturally silver does not represent a great possibility
for commercial use, and so copper, which is second on the list, is
almost universally employed. Pure copper is very soft and is
lacking in tensile strength; it is therefore alloyed, and it is also
hardened in the drawing process; both of these processes increase
its resistance slightly over the factor usually accorded it in the
standard table of specific conductivities of materials. In this
table, German silver (which is an alloy containing no silver whatever
and having but a few of its properties), cast iron, steel, carbon,
and similar substances will be found well down toward the end.
They are known as "high-resistance" conductors and are usually
used where a certain amount of resistance to the current is desirable.

It must be borne in mind that ability to conduct a given amount
of current without undue loss through resistance depends upon
the size and the length of the conductor quite as much as upon
the material. In other words, if a steel rail is only one-thirtieth
as good a conductor as a copper cable, it will require a cross-section
of steel thirty times as great as that of a copper cable in order to

382

Digitized by VjOOQlC

ELECTRICAL EQUIPMENT 9

conduct the current with the same ease — that is, to make a con-
ductor of equal resistance. An illustration of this may be seen
in the overhead copper wire of the usual trolley system. This
wire of about one-half inch diameter forms one of the conductors,
while the two steel rails form the "return". A similar example
may be found in what is known as the single-wire system of installa-
tion for an electric starter in automobiles. A single copper cable
conducts the current from the battery to the starting motor, while
the steel frame of the automobile is the return side of the circuit,
or vice versa.

Voltage Drop. It is evident that the resistance of a circuit
varies inversely as the size of the conductor — the larger the cross-
section of a conductor, the less its resistance — and increases directly
as its length, besides depending upon the specific resistance of the
material. The specific resistance of the metals constituting elec-
trical circuits on the automobile are (silver being 1.0); copper
1.13, varying more or less with its hardness; aluminum 2.0; soft
iron 7.40; and hard steel 21.0. Thus, 9.35 feet of No. 30 copper
wire are required for a resistance of one ohm, while only 5.9 inches
of hard steel wire of the same gage are required to present the same
amount of resistance to the current. If the length of the conductor
is doubled, its resistance is doubled, which accounts for the placing
of the storage battery as close as possible to the starting motor.
Furthermore, the heavy starting currents which are required by
the motor demand the use of heavy copper cable for this circuit.
If two wires are of the same length but one has a cross-section
three times that of the other, the resistance of the former is but
one-third that of the latter. If a circuit is made up of several
different jnaterials of different sizes joined in series with one
another, the total resistance will be the sum of the resistance of
the various parts.

In addition to being affected by the cross-section and the length,
the resistance is also influenced by the temperature. All metals
increase in resistance with an increase in temperature, that of copper
increasing approximately .22 per cent per degree Fahrenheit. The
change of resistance of one ohm per degree change in temperature
for a substance is termed its temperature coefficient. Metals have
a positive temperature coefficient; some materials, like carbon,

383

Digitized by

Google

10 ELECTRICAL EQUIPMENT

have a negative temperature coefficient, that is, they decrease
in resistance with an increase in temperature.

It is consequently necessary to employ wires of proper size
to carry the amount of current required by the apparatus in circuit
— such as lamps — without undue heating, which would cut down
the amount of current flowing. For the same reason it is also
desirable to make the circuits as short as practicable, since in addition
to cutting down the current, the resistance also cuts down the
effective voltage. That is/ there is a fall of potential, or drop in
voltage, between the source of current supply and the apparatus
utilizing it, due to the resistance of the conductors between them.
This voltage drop is further increased by joints in the wiring and
by switches. It is apparent that the lower the voltage of the source
of supply, the more important it becomes to minimize the loss,
or voltage drop, in the various circuits. For this reason lighting
or other circuits on the automobile should never be lengthened
where avoidable. When necessary to extend a circuit for any
reason, wire of the same diameter and character of insulation as
that forming the original circuit must be employed, and the joints
should be as few as possible, all mechanically tight, and well soldered.
The voltages employed in the electrical systems of automobiles
are so low — varying from 6 to 24 volts, with a strong tendency
to standardize the 6-volt system — that any increased resistance
is likely to cause unsatisfactory operation.

Non-Conductors. In going down through a table of specific
conductivities of various materials, the vanishing point is reached
with those that cease to be conductors at all. Such materials
are known as nonconductors or insulators, and some substances
vary in the degree of insulation they afford quite as much as other
materials do in their ability to conduct a current. Glass, rubber,
shellac, oil, paraffin wax, wood, and fabrics are all good insulators
when perfectly dry. Distilled water has such a high resistance
as to be almost an insulator, but in its natural state water contains
alkaline salts or other impurities that make it a conductor. Con-
sequently, when any otherwise good insulating substance is wet,
the current is likely to leak across the wet surface of the insulator.
This is particularly the case with a current of high potential, or
high tension, and explains why it is of the greatest importance

384

Digitized by CjOOQ IC

ELECTRICAL EQUIPMENT 11

to keep all parts of the secondary side of the ignition system perfectly
dry. The potential which causes the current to arc across the gap
of the spark plug is so high that it will leak across even slightly
damp surfaces, such as the porcelains of the plugs. This leakage
is often visible, especially in the dark, and it may also be detected
by placing the bare hand on the porcelain.

Just as the amount of current to be carried determines the
size of the conductor to be employed, so the potential or pressure
under which this current is transmitted determines the amount of
insulation that will be necessary. The latter is also affected, how-
ever, by mechanical reasons, for example, by the liability of the
conductor to chafing or abrasion. The best grades of copper
cable employed for both ignition and starting-lighting systems on
automobiles today are stranded, that is, composed of a number'
of fine wires, to make them flexible. The stranded cable is then
tinned to prevent corrosion due to the sulphur in the insulation,
after which it is covered with a soft-rubber compound of a thickness
dependent upon the purpose for which the wire is intended. For high-
tension ignition wire this rubber covering is about three-sixteenth inch
thick. This covering is vulcanized and is then further protected by
braided linen, or silk-cotton thread which is made waterproof by
being impregnated with shellac or some other insulating compound.

Circuits. When air under high pressure escapes from its
container, it simply mingles with the atmosphere, and as soon as
the difference in pressure is equalized there is no distinction between
it and air in general. But to equalize a difference in potential
of an electric current there must be a conducting path between
the points of high and low potential. This is termed a circuit.
Current to operate trolley cars is fed to the motors of the car from
the overhead wire and returns through the tracks to the generators
at the power house. This is known as a ground-return circuit.
In the single-wire electric starting system of an automobile, current
from the storage battery reaches the starting motor through the
starting switch and a single heavy cable, and returns through the
frame and other metal parts of the car itself, or vice versa. This
is another instance of a ground-return circuit.

Both the primary and secondary sides of the ignition system
of an automobile are also grounded circuits. In contrast with

385

Digitized by

Google

ELECTRICAL EQUIPMENT

this, the circuit may be composed of copper cables directly con-
necting both poles of the battery and switch with the starting
motor. The highly insulated cable employed for both ignition
and starting systems is expensive and the use of a single wire greatly
simplifies the connections, considerations which account for the
general use of this type of circuit. A circuit is said to be open when
there is a break in it which prevents the current from flowing, as

Storting Motor

<2 P P

rwmm

Battery

Qroijnd

(o)

wtt;

adliyht

Jtdmliyht

0|2*

-L

7hit light

O p

d Q

3ott*ry

(»)

Fig. 1. Typical Starting-Lighting Wiring Diagrams, (a) Series Circuit of
Starting Motor; (b) Multiple Circuit of Lamps

when the switch is opened, or when a connection or the wire itself
is broken.

Series Circuit. The connections between a storage battery,
switch, and starting motor, comprise the simplest form of circuit,
in which the motor is said to be in series with the battery, and
the cells of the battery are in series with one another. This is
termed a series circuit and a break in it at any point opens the
entire circuit. The starting motor, Fig. 1 (a), requires the entire
output of the storage battery for its operation.

386

Digitized by

Google

ELECTRICAL EQUIPMENT 13

To make clear the distinction between this and other forms
of circuit, it must be borne in mind that, in equalizing a potential
difference, electric current flows from the positive or plus side
of the source of supply, whether a battery or generator, to the negative
or minus side (plus and minus being arbitrary signs employed to
distinguish the positive and negative sides of a circuit or of an
instrument). The current is said to flow out on the positive side
of the circuit and to return on the negative side. In the case of a
series circuit as described, the current flows through each piece
of apparatus in turn; each receives all the current in the circuit
at a potential proportioned to the resistance of the apparatus in
question. For example, in the simple starter circuit referred to
above the starting motor receives the entire output of the 3-cell
storage battery at its full voltage of 6 volts, less the drop in voltage
due to the resistance of the circuit. If there were two starting
motors instead of one in the circuit, both in series, both would
receive all the current but at only half the voltage.

Multiple or Sfiuni Circuit. As opposed to this, in a multiple
circuit, Fig. 1 (b), in which every piece of apparatus is connected to
both sides of the circuit "in parallel", each piece of apparatus in
the circuit receives current at the same voltage but draws from
the circuit the current determined by its resistance. The failure or
withdrawal of any one or more instruments in a multiple or parallel
circuit has no effect on those remaining. The lighting circuits
of an automobile equipped with a 6-volt starting system are an
example of this. Each lamp is designed to burn to its maximum
illumination at 6 volts, but the 25-candle-power headlights take
more current than the 5-candle-power side lights or the 2-candle-
power taillight, owing to the difference in the size and resistance of
their filaments. Removing any one of the bulbs has no effect on
any of the others, because all are in parallel.

Series-Multiple Circuit. A combination of the two forms of
circuits is sometimes necessary to accommodate different devices
designed for varying voltages. For example, it is usually found
expedient to burn 6-volt lamps on the 12-volt starting systems.
In such a case, the starting motor is in series with the battery and
receives the full voltage as well as the full current. The lamps are
divided into two groups, each group comprising a parallel or mul-

387

Google

ELECTRICAL EQUIPMENT

tiple circuit of its own, and these two groups are connected in series
so that the lamps in each circuit receive 6 volts, but the circuit
as a whole takes the battery current at 12 volts. Such a combination

Fig. 2. Dry Cells in Series-Multiple for Ignition Circuit

is known as a series-parallel or series-multiple circuit and is more
or less commonly used for connecting dry cells for ignition use,
Fig. 2.

Circuits may also be in parallel, that is, practically a
circuit on a circuit. The method of connecting up the voltmeter
that is mounted on the dash of the car is an instance of this, a wire
being led from each side of the main circuit to the instrument.
The instrument is then said to be in shunt, Fig. 3, and the amount
of current that is diverted to it is entirely dependent on the
resistance. As a voltmeter is wound to a high resistance, Fig. 4,
it is designed to take very little current for its operation. The

VWWAA ME

Fig. 3. Diagram Showing How Voltmeter Is
Shunted in the Circuit

ammeter, Fig. 5, on the other hand, is intended to indicate the entire
current output of the generator on charge or discharge, and is
accordingly connected in series so that all the current passes through

388

Digitized by

Google

ELECTRICAL EQUIPMENT

Diagram of Voltmeter Principle

it. (Owing to the heavy rush of current taken by a starting motor
in overcoming the inertia of the gasoline engine, the ammeter is
not included in this circuit.)
Short-Circuits and
Grounds. The previous par-
agraphs have made clear the
necessity for having a com-
plete path or circuit for the
current in order that its power
may be utilized. There must
be a connecting cable on one
side and there must be a re-
turn on the other (grounded
circuit). If instead of pass-
ing through the apparatus,
such as the starting motor,
the current finds an easier
path through an abrasion in
the insulation of the cable
and some metal part against
which that touches, it is
said to be short-circuited. A
case such as that cited,
where a stripped cable
touches a metal part, so
that the current completes
the circuit without passing
through the motor, is
usually termed a ground.
This should not be confused
with the ground return pre-
viously mentioned as a
characteristic of the wiring
of many of the starting and
lighting systems in use on
automobiles today. It is indeed a ground return but not an
intentional one. It is also true that a ground of this type is
a short circuit, but it does not necessarily follow from this that

-O-s*

B-(y

Fig. 5. Diagram of Ammeter Principle

389

Digitized by

Google

16 ELECTRICAL EQUIPMENT

all short circuits are grounds, as short circuits may occur from
many other causes — for instance, where two wires touch at unin-
sulated points or where stray metal makes contact with connec-
tions, etc. #

Size of Conductors. The influence of the factor of resistance
makes plain the reason for using wires of different sizes for the various
circuits of the ignition starting and lighting systems of the auto-
mobile. If an ample flow of compressed air is desired for power
purposes, a liberal outlet must be provided, while if only a small
spray is required, as for cleaning purposes, a small-bore tube will
suffice. If we try to employ the small-tube line for power pur-
poses, we shall not gain the desired result because its resistance is
so great that it will not permit a sufficient flow of air. For the
same reason a conductor of much larger diameter and, therefore, of
correspondingly low resistance must be employed to handle the
heavy current necessary to operate the electric starting motor, than
is needed for the comparatively small current whidh is demanded by
the ignition system.

Whether it is mechanical or electrical in its nature, the power
necessary to overcome resistance is liberated in the form of heat.
Mechanical resistance is friction and its presence between moving
bodies always generates heat. Electrical resistance may, for the
purpose of illustration, be termed internal or molecular friction,
and it also results in heat. The extent of the rise in temperature
of a conductor or wire, depends entirely upon the proportion that
its size and, consequently, its current-carrying ability bear to the
amount of current that is sent through it. Roughly speaking, if
a wire is three-fourths the size it should be to carry the starting
current, it will become uncomfortably warm to the hand after the
motor has been operated several times in succession. If it is only
one-half the size it should be, continuous operation of the starting
motor for a few minutes will doubtless burn off most of the insulation.
Further reducing its size would cause the wire to become so hot
as to set fire to the insulation the moment the current was turned
on, and any great decrease in diameter would result in the immediate
fusing of the wire itself. The wire would literally "burn up" and
in a flash.

It would not be practical to attempt to conduct live steam

390

Digitized by

Google

ELECTRICAL EQUIPMENT 17

TABLE I
American Wire Qage (B. & S.)

at high pressure through a cardboard tube. Nor is it any more
so to attempt to send a heavy current through "any old piece of
wire". Electric lighting and starting systems as they exist on cars
today are of all degrees of merit. The cars themselves have reached
a stage of reliability where their useful life is now on the average
from five to ten years or more. Consequently, there are a great
many cars in service equipped with electric systems that were
brought out several years ago. These are the cars on which the
repair man will get a great deal of his early experience, and he
need not take it for granted that just because the electric systems
have worked for a certain length of time they were properly designed
at the outset. Overheated conductors not only indicate excessive
resistance caused by small wires or poor joints, but they also indicate
a waste of power that is being drawn from the battery and dissi-
pated in the air. The utilization of this energy or rather the
prevention of its transformation into heat would mean all the
difference between poor and good operation between an efficient
and a wasteful system.

Digitized by

Google

18 ELECTRICAL EQUIPMENT

Heating Effect of Current. The amount of beat that a given
current will produce in passing through a conductor of a certain
size is expressed by Joule's law: The number of heat units developed
in a conductor is proportionate to its resistance, to the square of the
current, and to the time that the current lasts.

The heat generated, therefore, increases in direct proportion to
the resistance. For example, if the cable between the starting
motor and the battery be replaced by one-half its size, the resistance"
will be doubled and the heat generated will increase in the same pro-
portion, the current remaining the same in both instances. Increasing
the current, however, adds to the amount of heat generated, as the
square of the increase. Thus, if with the original starting cable above
mentioned, the amount of current necessary to start the motor has
to be doubled, owing to gummed lubricating oil or stiff bearings, the
volume of heat generated will increase fourfold. The amount of
heat generated also increases in direct proportion to the time that
the current lasts. It will be easy to realize from this why abnormal
conditions may quickly bring the heating effect of the current to a
point where the insulation of the wires, or even the wires themselves,
may be endangered. For instance, in the case of a motor that is
very hard to start, the discharge from the battery is greatly increased
in turning it over, and the starting motor must be operated for a very
much longer period to get the engine under way, causing a direct
increase in the heating effect, due to the longer time that the current
is passing through the cable, and a fourfold increase for the addi-
tional current necessary.

Heat Generated in Starting Motor. Take the case of a motor
that requires 150 amperes for the first few seconds and 50 amperes
once the engine is turning over freely. If stiff bearings or gummed
oil cause the initial current to rise to 200 amperes and the running
current to 80 amperes for a period three times as long as would ordi-
narily be required to start, there will be a very considerable increase
in the number of heat units generated. This is one of the reasons why
it is good practice to use the starting motor intermittently when the
engine does not at once fire and take up its own cycle, instead of
running the starting motor continuously until the engine begins to
fire and generate its own power. A much more important reason,
however, is the fact that the intermittent use of the starting motor

392

Digitized by

Google

ELECTRICAL EQUIPMENT 19

is not nearly so hard on the battery, as the storage battery recu-
perates very quickly when given short periods of rest between the
demands for its power. Running the starting motor for ten periods
of 30 seconds each, with a like interval between the attempts to start,
will not discharge the battery anything like as much as will operating
the starting motor continuously for five minutes. A longer rest
between trials will be of greater benefit to the battery.

Heating Effect on Lamps and Fuses. It must not be concluded
from the above that the heating effect of the current is always detri- -
mental, as it is taken advantage of in many ways. Two of the com-
monest of these are the incandescent lamp and the fuse. In the case
of the former, the increase in heat with an increase in resistance is
mainly depended upon, the filament being made of such a size that
a given amount of current at a certain voltage will just bring it to
incandescence. For this reason an increase in the current, or voltage,
will burn the filament and destroy the lamp. The fact that the
heating effect increases as the square of the current is taken advantage
of in the design of fuses which are made of soft alloys that will melt
at comparatively low temperatures. Resistance is also a factor in the
fuse, as in cutting down the cross-section of the fusible wire the resist-
ance is increased, while the current-carrying capacity of the wire is
decreased. The cross-section, or diameter, of the fuse is gaged to
carry the amount of current that is a safe load for the circuit and
the apparatus in it plus a reasonable factor of safety to prevent
the fuse from burning out, with a small percentage of increase that
would do no damage. For example, a 10-ampere fuse, such as is
used in connection with many automobile-lighting generators, would
seldom burn out with an increase in the current to 12 amperes or
even to 15 amperes for short periods, as the time element is also
important. Some other applications of the heating effect are electric
welding, blasting fuses, soldering coppers, cooking utensils, and the like.

Chemical Effect of Current. The passage of an electric current
likewise has a chemical effect depending upon the nature of the con-
ductor. This may take various forms, such as the conversion of one
chemical compound into another, as in the case of the storage battery ;
the decomposition of water into hydrogen and oxygen; the deposition
of metals, as in electroplating; or the decomposition of metals, as
in electrolysis.

393

Digitized by

Google

ELECTRICAL EQUIPMENT

TABLE II
Carrying Capacity of Wires

Rubber

Other

Insulation

B. & 8. Gage

Circular Mils

Amperes

1,624

2,583

4,107

6,530

10,380

16,510

26,250

33,100

41,740

52,630

110

66,370

131

83,690

107

156

105,500

127

185

133,100

150

220

000

167,800

177

262

0000

211,000

210

312

MAGNETISM

Natural and Artificial Magnets. It has been known for many
centuries that some specimens of the ore known as magnetite (Fe 3 4 )

have the property of attracting small bits
of iron and steel, Fig. 6. This ore proba-
bly received its name from the fact that it
is abundant in the province of Magnesia
in Thessaly, although the Latin writer
Pliny says that the word magnet is de-
rived from the name of the Greek shep-
herd Magnes, who, on the top of Mount
Ida, observed the attraction of a large
stone for his iron crook. Pieces of ore
which exhibit this attractive property
for iron or steel are known as natural
magnets.

It was also known to the ancients
that artificial magnets could be made by-
stroking pieces of steel with natural mag-
Lodestone agne or nets, but it was not until the twelfth

394

Digitized by

Google

ELECTRICAL EQUIPMENT

century that the discovery was made that a suspended magnet
would assume a north-and-south position. Because of this prop-
erty, natural magnets came to be known as lodestones (leading

stones) ; and magnets, either arti- _=_,

ficial or natural, began to be

Fig. 7. Bar Magnet

It is thought to have been

Fig. 8. Horseshoe Magnet

used for determining directions.
The first mention of the use of
a compass in Europe was in 1190.
introduced from China.

Artificial magnets are now
made either by repeatedly strok-
ing a bar of steel, first from the
middle to one extremity with
one of the ends, or poles, of a
magnet, and then from the mid-
dle to the other extremity with the other pole; or else by passing
electric currents about the bar in a manner to be described later.
The form shown in Fig. 7 is called a
bar magnet, that shown in Fig. 8 is a
horseshoe magnet.

Poles of a Magnet. If a magnet
is dipped into iron filings, the filings
are observed to cling in tufts near the
ends, but scarcely at all near the mid-
dle, Fig. 9. These places near the
ends of the magnet, in which its
strength seems to be concentrated,
are called the poles of the magnet.
It has been decided to call the end
of a freely suspended magnet which
points to the north, the north-seek-
ing, or north pole, and it is commonly
designated by the letter N. The other
end is called the south-seeking, or
south pole, and is designated by the letter S.
which the compass needle points is called the magnetic meridian.

Laws of Magnetic Attraction and Repulsion. In the experiment
with the iron filings no particular difference was observed between

Fig. 9.

Location of Poles of a
Magnet

The direction in

395

Digitized by

Google

ELECTRICAL EQUIPMENT

the action of the two poles. That there is a difference, however,
may be shown by experimenting with two magnets, either of which
may be suspended, Fig. 10. If two N poles are brought near each
other, each is found to repel the other. The S poles likewise are
found to act in the same way. But the N pole of one magnet is
found to be attracted by the S pole of the other. The results of
these experiments may be summarized in the general law: Magnet
poles of like kind repel each other, while poles of unlike kind attract.
This force of attraction or repulsion between poles is found,
like gravitation, to vary inversely as the square of the distance
between the poles; that is, separating two poles to twice their original
distance reduces the force acting between them to one-fourth its

original value, and separating them three
times their original distance reduces the
force to one-ninth its original value, etc.
Magnetic Substances. Iron and
steel are the only common substances
which exhibit magnetic properties to a
marked degree. Nickel and cobalt, how-
ever, are also attracted appreciably by
strong magnets. Bismuth, antimony,
and a number of other substances are
actually repelled instead of attracted,
but the repulsion is very small. Until
quite recently, iron and steel were the
only substances whose magnetic prop-
erties were sufficiently strong to make
them of any value as magnets. Recently, however, it has been
discovered that it is possible to make rather strongly magnetic
alloys out of non-magnetic materials. For example, a mixture of
65 per cent copper, 27 per cent manganese, and 8 per cent aluminum
is rather strongly magnetic. These are known as the Hevssler alloys.
Electromagnets. The identity of magnetism with electricity
is readily established by some very simple experiments that have
been repeated so often as to become classics. By taking a bar of
iron and winding some insulated wire around it in the form of a
coil and then connecting the terminals of this coil with a battery
or other source of current, the bar becomes magnetic. One end

Fig. 10. Experiment Proving the
Law of Magnetic Attraction

lagn<
idRe

and Repulsion

396

Digitized by

Google

ELECTRICAL EQUIPMENT 23

of it is the positive, plus, or north pole of the magnet, and the other
the negative, minus, or south pole. Break the connections or
otherwise "open the circuit" and the magnetism instantly dis-
appears. Reverse the connections to the battery by attaching
the wire previously at the positive pole to the negative, and vice
versa, complete the circuit again, and the bar is once more magnetic,
but now the pole that was previously north or positive is south.
The bar is once more a magnet, but its polarity has been reversed
by reversing the direction of flow of the magnetizing current. This
bar of iron with a coil of wire wound around it is known as an electro-
magnet because it becomes magnetic only when a current is passing
through the coil. If a rod of hard steel is substituted for the bar
of soft iron and the current passed through it, the bar will be found
to be strongly magnetic after the current has been shut off. That
is, the bar of steel has, through the action of the current, become
a permanent magnet like that shown in Fig. 7. This method is
often used for making permanent magnets from hardened steel.

To determine the polarity of a magnet it is only necessary
to hold a small pocket compass near it; let the compass needle
come to rest normally and then bring the compass near to one
end of the magnet. If the needle continues to point in the same
direction and gives evidences of being strongly attracted to the
magnet, the end to which it is being held is the south pole. Bring
the compass near to the other end of the magnet, and the needle
will turn away sharply, showing that like poles repel each other.

Magnetic Field. If a bar magnet is placed on a sheet of glass
and a handful of fine iron filings thrown around it, they will auto-
matically assume the position shown by Fig. 11. As originally
dropped on the glass some of the filings may not be within reach
of the influence of the magnet, but if the glass be gently tapped
and tilted slightly, first one way and then another, they will arrange
themselves in the symmetrical pattern shown. This gives a graphic
illustration of the field of influence of the magnet, usually termed
the magnetic field. This field is most powerful at the poles, as
will be noted by the attraction of the filings at the N and S points,
representing the north and south poles of the magnet. At inter-
mediate points along the length of the magnet the filings will be
seen to have placed themselves as if to indicate a circular movement

397

Digitized by

Google

ELECTRICAL EQUIPMENT

of the lines of force. This is the magnetic circuit and these concentric
circles represent the magnetic flux, or flow. If the magnet is then
removed from the glass and the north pole extension of it placed

Fig. 11. Field of Force about a Bar
Magnet

Fig. 12. Field of Force about a Single
Pole ^^

centrally under the glass, a striking illustration is given of the
magnetic field around the pole, Fig. 12. A bar magnet has been
shown here for purposes of simplicity, but a common horseshoe
magnet such as can be had for a few cents will serve equally well
for the experiments.

By carrying the experiments a little further, the identity of
magnetism and electricity is strikingly shown. Take a piece of

Fig. 13.

Down
Field about a Conductor Carrying a Current

cardboard or heavy paper, punch a hole through its center and
pass through this hole a wire connected to two or three dry cells.
Scatter on the paper the filings used in the previous experiments,

398

Digitized by

Google

ELECTRICAL EQUIPMENT 25

then complete the circuit by touching the end of the wire to the
other terminal of the battery. The filings will immediately arrange
themselves as shown in Fig. 13, illustrating the magnetic field
which is always present around any current-carrying conductor.

Lines of Magnetic Force. Punch another hole through the
cardboard and rearrange the circuit of the dry cells so that the wire
passes from the positive battery terminal up through one hole
of the cardboard and down through the other hole to the zinc or
negative. Scatter the filings as before and touch the loose end
of the wire to the negative terminal. The arrangement of the
filings will then be that shown in Fig. 14, the positive field being
at the left and the negative at the right. The fact that the mag-
netic fields overlap in the curious
alignment indicated is simply
due to the proximity of the con-
ductors carrying the current.

Another simple method of
demonstrating the identity of
electricity and magnetism is to
place an ordinary pocket com-
pass above or below a wire which
is running north and south and is

carrying a current. If this is a Fig. u. Field about a Cou

direct current the needle of the

compass will tend to set its axis at right angles to the wire, that
is parallel to the lines of force; the direction of the deflection will
depend upon the direction of the current. This test, therefore,
not only indicates the magnetic field about the wire bearing a current,
but shows its direction.

All of the arrangements which the filings assume under the
influence of either a magnet or a current, as shown by the various
llustrations, indicate that the stresses in the medium surrounding
a magnet or current-carrying conductor follow certain definite
lines, the lines showing the direction of stress at any point. These
are termed lines of force.

Solenoids* It has been determined that the direction of the
current and that of the resulting magnetic force are related to one
another as the rotation and travel of an ordinary, or right-hand,

309

Digitized by

Google

ELECTRICAL EQUIPMENT

Fig. 15. Direction of Magnetio Lines about a
Conductor

screw thread. Consequently, if the conductor be looped instead
of straight, the lines of magnetic force will surround it as shown
in Fig. 15. The field of such a loop, if outlined with the aid of
filings or explored with a compass needle, will be seen to retain

the general character of
the field surrounding a
straight conductor, so
that all the lines will
leave by one face and
return by the other, the
entire number passing
through the loop. Hence one face of the loop will be equivalent
to the north pole of a magnet and the other face to the south
pole. In fact, the loop will act exactly as if it were a thin disk
magnetized perpendicularly to the plane. By winding a number
of these loops to make a hollow coil, there is formed a solenoid,
Fig. 16. Exploring its field shows that the lines of force pass
directly through the center or opening of the hollow coil, leaving
by one end and returning by the opposite end, as indicated.

If such a solenoid is held vertically and a bar of soft iron placed
so that it extends for an inch or so into the lower end of the solenoid,
a current passed through the latter will cause the iron to be violently
drawn up into the coil and held there. As long as the current
flows, this rod is strongly magnetic and has all the properties already

-*--,^ described. Butthemo-

^.-~~' ~~^^ % ment the current is shut

off, the magnetism prac-
tically disappears and
the rod immediately
drops out of the coil by
its own weight. Re-
versing the direction of
the current reverses the
polarity of the solenoid
but makes the effect the same; increasing or decreasing the amount
of current sent through it increases or decreases correspondingly the
strength of its magnetic field. The principle of the solenoid is used
in starting systems to operate electromagnetic starting switches

F5g. 16. Magnetio Field about a Solenoid

400

Digitized by

Google

ELECTRICAL EQUIPMENT 27

Effect of Iron Core on Strength of Solenoid. The magnetic
flux or flow of lines of force through a solenoid is much greater
when an iron core is present than when the coil is empty or a core
of wood is inserted. The magnetism flows through the iron as a
current would. Soft iron is said to have a high magnetic permear
bility. The magnetic permeability of air (or a vacuum) is taken
as unity and other substances rated accordingly: for very soft iron
it may be as high as 2500, while for substances such as silk, cotton,
wood, glass, brass, copper, and lead, it is unity, the same as for air.
Such metals are said to be non-magnetic. All insulators are
likewise non-magnetic.

INDUCTION PRINCIPLES IN GENERATORS AND MOTORS

Induction. When a current suddenly flows in a wire place J
close to another wire, a delicate measuring instrument such as a
galvanometer will indicate a momentary current in the second wire.
When the current in the first wire ceases, that in the second will
likewise cease immediately. This phenomenon is known as induc-
tion, and a current is said to have been induced in the second wire.

Winding the first wire in the form of a coil and bringing this
coil close to the second wire, will give the induced current con-
siderably greater strength. The induced effect is still further
increased in three other ways: first, by inserting an iron core in the
coil; second, by winding the second wire in the form of a coil; and,
third, by bringing these coils as close together as possible by winding
one directly over the other.

Transformer Principle. The arrangement just discussed is
termed an induction coil or transformer (step-up) and is universally
employed in connection with ignition systems. The character
of the induced current depends upon the relation that the first
coil, termed the primary, bears to the second coil, known as the
secondary. In the usual ignition coil the primary consists of a
few turns of comparatively heavy wire, and a current of about
2 amperes (4 to 5 on starting) is sent through it at a low voltage, one
seldom exceeding 6 volts. The secondary coil, however, consists
of a great number of turns of exceedingly fine wire, and the current
induced in this is proportional to the relative number of turns
between the two and the value of the current in the primary. The

401

Digitized by

Google

28 ELECTRICAL EQUIPMENT

secondary current is accordingly of extremely high potential but
of low current value.

In the commercial step-down transformer, the relations described
above are reversed, the primary being a coil of many turns of fine
wire, while the secondary is a comparatively small coil of few turns.
In this case, the current is received at the transformer at high
voltage and correspondingly reduced amperage, and it steps the
voltage down to the standard generally employed, 110 or 220 volts,
and increases the amount of current proportionately.

Self-induction. It has already been pointed out that electricity
may be put under pressure or potential, and that the greater this
pressure, the greater the amount of work a certain amperage of
current will perform, thus affording a direct analogy with steam,
water, or air under pressure. An electric current also possesses
other characteristics corresponding to mechanical equivalents.
Chief among these is inertia and it is the latter that is responsible
for what is known as self-induction.

When a current is passed through a coil of wire, a strong magnetic
field is set up in the coil owing to the concentration of a great many
turns of wire in a small compass. By inserting a core of soft iron
wires into this coil, the magnetic field is greatly strengthened, since
the permeability of the iron affords a path of slight resistance for
the magnetic circuit. There is, of course, a magnetic field sur-
rounding every conductor in a circuit when the current is passing,
but the iron core of the solenoid converts a certain part of this
current into magnetism. An appreciable time is necessary after
the circuit is closed for such a coil "to build up". This "building
up" consists of saturating the core with magnetism.

When the circuit is suddenly opened, the current that has been
stored in this core in the form of magnetism is as quickly retrans-
formed and its value is impressed upon the circuit, causing a flash
at the break. The flash is also aggravated by a certain amount
of inertia which the current possesses. We may illustrate this
by a stream of water flowing in a pipe. If the water is suddenly
shut off by the closing of a valve, it tends to keep on flowing and
momentarily causes a great increase in the pressure against the
face of the valve, resulting in the familiar "water hammer". The
same thing happens when a circuit is suddenly broken, and the

402

Digitized by

Google

ELECTRICAL EQUIPMENT 29

higher the potential the more marked this effect will be. The
current tends to keep on flowing, and the extra potential which
this self-induction gives it will cause it to arc, or bridge, the gap at
the break, unless a condenser is provided to take care of this. Every
circuit possesses self-induction, but it is only marked in circuits
having considerable inductance, that is, in coils, and especially those
with iron cores, such as induction coils, circuit breakers, etc.

Capacity of Condensers. Every conductor of electricity has
capacity to hold a charge just as a vessel holds water. But the
capacity of a conductor is dependent upon its surface area rather than
its cross-section, or cubic volume, and is also influenced by surround-
ing conditions. Where it is desired to accumulate a considerable
charge, as for an ignition spark, a special form of capacity is utilized.
This is known as a condenser (a detailed description of which is
given later in connection with ignition coils). The ability of a
condenser to absorb the rise in potential that occurs through self-
induction whenever a circuit containing inductance is opened is
also utilized to prevent sparking at contact points. Comparatively
small condensers are necessary for this purpose, and they are shunted
around the contact points, that is, connected in parallel with the
latter. When the circuit is opened the excess energy of the circuit
passes into the condenser instead of forming a hot spark at the
contacts. The occurrence of any undue amount of sparking at
contacts should accordingly be made the subject of an investigation
of the condenser connections, or of the condenser itself.

Comparison of Generator Current to Water Flow. The com-
parison of air in a room has been made to illustrate the presence
of electricity and its characteristics, since it may be made to partake
of all the latter by being put under pressure, allowed to escape
through various sized outlets, and made to perform work of differing
nature by being utilized at varying pressures and volumes, exactly
as electricity is. Where an electric current is produced by a gener-
ator, however, the older simile of water flowing under pressure due
to the impulse of a pump may serve to make it much clearer.
This comparison of a water pump and its piping with an electric
generator and its circuits is known as a hydraulic analogue, and, it
may be added, there is scarcely any characteristic or function of
the electrical current that cannot be similarly compared.

403

Digitized by

Google

30 ELECTRICAL EQUIPMENT

Take, for example, a waterworks system of the type in which
a large pump at the power house draws water from artesian wells
or a reservoir and forces it into a closed system of piping. Located
on this piping system are all the house outlets, street hydrants, and
the like. The speed of the pump is regulated so as to keep a certain
amount of pressure on the water in the pipes, based upon the average
demand at different periods of the day. The pressure is reduced at
night and is increased at any time, day or night, in case of fire.

Pressure and Voltage. This constant pressure in pounds per
square inch that the pumps maintain on the supply of water in the
entire piping system is the exact counterpart of the voltage, or electro-
motive force, produced by a dynamo, or generator, when running.
Just as the pressure exerted on the water by the pumps depends
upon the speed of the latter, so the voltage produced by the dynamo
is proportional to its speed. In the case of the pump, the pressure
depends upon the number of times that, the pistons of the pump
reciprocate; in the dynamo, upon the number of times that the
coils, or windings, of the armature cut the lines of force of the mag-
netic field in which it revolves. This is explained in detail later
in connection with generator principles.

When the pump moves very slowly, there is very little pressure
produced in the pipes, and this is the case with the dynamo to an
even greater extent, since dynamos are usually designed to run at
very much higher speeds, and consequently their voltage, or pressure,
drops off very sharply at low speeds. This will explain why the
majority of lighting generators on automobiles do not begin to charge
the battery until the motor of the car is running at a speed equiva-
lent to ten to fifteen miles per hour, as explaine4 later. At low
speeds they do not generate sufficient voltage to overcome that of
the battery.

Fall in Pressure. When either a pump or a dynamo is running
at a constant speed, the pressure, or voltage, produced at the machine
is practically constant. But in the case of the water system, the
pressure is not the same at the outlet of a branch line a mile away
from the power house as it is at the delivery end of the pump, nor
is the voltage on a branch circuit at a great distance from the dynamo
the same as it is at the terminals of the latter, consequently,
the fall in pressure in the water piping is the exact counterpart of

404

Digitized by CjOOQIC

ELECTRICAL EQUIPMENT 31

the drop in voltage on the electric circuit due to the resistance of
the wires. In the case of the water supply, the friction encountered
by the water in passing through the pipes is analogous to the resist-
ance which the electric current must overcome, except that bends
in a wire do not impose any greater resistance to the current than
the same length of wire when straight, whereas bends in piping greatly
add to the friction with a correspondingly greater drop in pressure.

Friction and Resistance. There is, in consequence, almost an
exact parallel between the mechanical friction of water passing
through a pipe and that of the electric current passing through a
wire, as it is commonly said to do. Friction in water piping is
inversely proportional to the size of the pipe in proportion to the
pressure to which the water is subjected, and is directly proportional
to the length of the pipe in exactly the same way that a wire opposes
more resistance to the electric current the smaller the wire is, and
the amount of resistance also increases with the length of the wire
itself. In both cases, the product of this friction, or resistance, is
heat; and it results in a drop in pressure, whether mechanical or
electrical.

Current and Volume. So far the comparison has been limited
entirely to the pressure exerted by the pump on the supply line as
compared with the voltage of the generator imposed on the circuit.
In a similar way the flow of water from the pipe line may be compared
with that of the current in an electrical circuit. Assume, for example,
that, in the case of the water-supply system, the pumps generate a
pressure of 100 pounds to the square inch. Eliminating from con-
sideration any drop in pressure between the pump and outlet as
only tending to confuse the comparison, suppose a half-inch faucet
to be opened at a distant part of the system. Then there will flow
from the pipe an amount of water proportioned to the size of the
outlet times the pressure, or head, back of it. Let us assume that
this will be one cubic foot per minute, or, roughly, eight gallons.

In the same way, assume that the generator imposes a pressure
of 100 volts on the line and, for purposes of comparison, there is
no drop between the generator and the end of the line. So long as
there is no outlet open there is pressure on the water in the supply
system, but no flow. This is likewise the case with the electric
circuit. The voltage is present as long as the armature of the dynamo

405

Digitized by

Google

32 ELECTRICAL EQUIPMENT

is revolving, but there is no flow of current in the circuit. A small
fan motor, corresponding to the half-inch faucet, is switched on at
a distant part of the circuit. There is then a flow of current of,
say one ampere. In this case, the hydraulic analogue reflects exactly
the action of the current as compared with the water supply in a
pipe. If, instead of opening a small house faucet, we open the valve
of a branch main a foot in diameter, there is a correspondingly greater
volume of water flowing, but the pressure remains the same. On the
other hand, if, instead of a small fan motor, a five-horsepower motor
is switched into the circuit, the outflow of current will be equivalent
to five horsepower, though the voltage of the circuit will remain
the same. (There is, of course, always a voltage drop with every
piece of apparatus that the current passes through before com-
pleting the circuit by returning to the generator, just as there is a
drop in water pressure for every additional length of pipe or open
outlet in the system ; but, to keep the comparison clear and simple,
this is not taken into consideration here.) Thus, in one case, we
have one cubic foot of water per minute flowing under a head, or
pressure, of 100 pounds per square inch; in the other, a current of
one ampere at a voltage of 100; also the fact that the volume of
either water or electricity that will flow depends upon the resist-
ance of the outlet. The fan motor is wound to a high resistance,
and, consequently, only one ampere of current is required to
operate it at its maximum speed. In the same way, the i-inch out-
let will permit only one cubic foot of water to escape per minute.
Increasing the size of the outlet in either case increases the flow
correspondingly. The simile holds good with the water system
up to the point where the outlet becomes too large to permit the
pumps to maintain the pressure; but, in the case of the electric
generator, the resistance cannot be decreased to zero, since this
would result in a short-circuit permitting the entire current output
of the dynamo to flow. Unless the dynamo were protected by cir-
cuit breakers and fuses, the functions of both of which are explained
later, the windings of the machine would be burned out.

Power Comparison. To go back to the simile between water
and current flow, it will be noted that in one case there is a flow
of one cubic foot per minute at 100 pounds to the square inch, and,
in the other, a flow of one ampere of current at 100 volts. This

406

Digitized by

Google

ELECTRICAL EQUIPMENT 33

flow of water represents power just as the flow of electric current
does, and it may be utilized in a similar manner. The product of
the volume times the pressure would give foot-pounds in the case
of the water and watts in the case of the electrical energy, in
other words, one ampere times 100 volts, or 100 watts — almost
one-seventh of a horsepower.

Circuits. The simile of the water-supply system does not
correspond exactly to any type of electric circuit, in that the water
does not return to the pump in any case, as the current always must
to the generator, to complete the circuit. But it does afford a com-
parison of the characteristics of both series and multiple circuits,
showing to what an extent the illustration of electrical principles
may be carried by means of a simple mechanical analogue. For
instance, the opening of one outlet after another in a water system
reduces the pressure in the entire system, just as the insertion of
one piece of apparatus after another in a series electric circuit
causes a corresponding drop in voltage for each addition, except,
of course, that in case of the series electric circuit it must always
be complete, regardless of whether one or a dozen different pieces
of apparatus be included in it. In other words, the current must
pass through each one of them in turn to complete the circuit. On
the other hand, the water system has some of the characteristics
of a multiple, or parallel, electric circuit, in that the opening of one
outlet does not prevent the use of others, whereas in the series circuit,
the breakdown of one piece of apparatus, such as a motor or a lamp,
puts all the others out of action by opening the circuit.

The comparison may be carried still further to illustrate other
attributes of the electric circuit. For example, if there be a bad
break in one of the large mains of the water system, no water will
reach smaller outlets beyond the break in the main, the entire volume
flowing out of this opening. This corresponds very closely to a
ground or short-circuit on an electric circuit. If one of the wires,
instead of carrying the current to the motors, permits its supply to
return to the generator by a shorter path, due to faulty insulation
or a broken wire touching the ground, no useful work will be per-
formed by the current. It will escape and be wasted just as the
water is, with this important difference, however, that in the
case of the water pumps, the break in the main will be evidenced

407

Digitized by VjOOQlC

34 ELECTRICAL EQUIPMENT

only by a marked decrease in the pressure, and the pumps will run
to no purpose, whereas the electric generator will still continue to
generate its full voltage, and, unless the grounded circuit caused by the

break has sufficient resistance,

""^v^"""""^^ the circuit breaker, or fuses,

_ " /£ \^v must operate to protect it.

N ^ ^F^SZ/^^J S GENERATOR PRINCIPLES

\ <r^SS^"" : ^ Classification. All dy-
\^ ^"^v J^SW namo-electric machines are

Fig. 17. Elementary Principle of Generator Commercial applications of

Faraday's discovery of in-
duced currents in 1831. They are all designed to transform the
mechanical energy of a steam engine, a waterfall, a gasoline engine,
etc., into the energy of an electric current. Whenever large currents
are required — for example, in running street cars; in systems of
lighting and heating; in the smelting, welding, and refining of metals;
the charging of storage batteries, etc. — they are always produced
by dynamo-electric machines.

There are two kinds of generators (1) d.c, or those producing a
unidirectional (direct) current, that is, one which always flows in
the same direction in the external circuit, and (2) a.c, or those
producing an alternating current, that is, one which reverses in
direction continuously throughout the entire circuit.

Elementary Dynamo. Whenever lines of magnetic flux are cut by
a conductor, for example, by a wire passing through them, an e.m.f.
(electromotive force) is produced in the conductor, and the strength
of this e.m.f. is entirely dependent upon the speed at which the
conductor passes through the magnetic field. If, at the time that
this is done, the ends of the wire are brought together to form a
circuit, a current wall be induced in the conductor. The simplest
form of generator would consist of a single loop of wire ABCD
arranged to rotate in a magnetic field, as shown by Fig. 17. Having
its plane parallel to the direction of the magnetic flux, the loop, if
it be rotated to the left as shown, will have an e.m.f. induced in it
that will tend to cause a current to flow in the direction shown by
the arrows. The e.m.f.'s induced in AB and "CD for the position
shown will have their maximum values since the wires are then cut-

408

Digitized by

Google

ELECTRICAL EQUIPMENT

360°

ting the magnetic flux at right angles and are consequently cutting
more lines of force per second than in any other part of the revo-
lution. Note that as CD moves up, AB moves down (and vice
versa) across the magnetic flux so that the induced currents in all
parts of the loop at any instant are
flowing in one direction. The value
of this e.m.f. depends upon the
speed, and as the loop approaches
the 90-degree, or vertical, position,
the e.m.f. decreases because the rate
of cutting is diminishing, until when
the loop is vertical both the cutting
of the magnetic flux and the generated e.m.f. are at zero. If the rota-
tion is continued, the rate again gradually increases, until at 180
degrees it is once more a maximum. The cutting, however, in the two
quadrants following the 90-degree position has been in the opposite
direction to that occurring in the first quadrant, so that the direction

Fig. 18. Dynamo E. M. F. Curve

Fig. 19. Simple Form of Generator Showing Arrangement of Brushes
in Contact with Commutator

of the e.m.f. generated is reversed. Plotting this through an entire
rotation gives the curve shown in Fig. 18. Such an e.m.f. is termed
alternating because of its reversal from positive to negative values,
first in one direction and then in the other, through the circuit.
It cannot be utilized for charging a storage battery, and hence it
is not employed in connection with starting and lighting dynamos
and motors. To convert an alternating current into a direct or
continuous current, a commutator must be added.

Commutators. Fig. 19 illustrates a commutator in its simplest
form. It may be imagined as consisting of a small brass tube
which has been sawed in two longitudinally, the halves being mounted

409

Digitized by

Google

ELECTRICAL EQUIPMENT

Fig. 20. Commutator with Double Turn

on a wooden rod. The wood and the two cuts in the tube insulate
the halves from each other. Each one of these halves is connected
to one terminal of the loop, as shown in the illustration, Fig. 20.
Against this commutator, Fig.
19, two brushes bear at opposite
points and lead the current due to
the generated e.m.f. to the ex-
ternal circuit. If these brushes
are so set that each half of the
split tube moves out of contact
with one brush and into contact
with another at the instant when
the loop is passing through the
positions where the rate of cutting is minimum (as indicated in
the enlarged end view of the commutator shown at A), a unidi-
rectional current will be produced, but it will be of the pulsating
character as indicated by the curve for one cycle shown in Fig. 21.

This would also be the case,
if instead of the single loop, a coil
wound on an iron ring be substi-
tuted, as in Fig. 22, the only effect
of this being to increase the e.m.f.
by increasing the number of times

the electrical circuit cuts the magnetic flux. Now assume that two
coils are connected to the commutator bars, instead of the single
loop, shown in Fig. 22. This arrangement will give the simple
device shown in Fig. 23, called an armature. The two coils are

O 8 90° 180° 270° 000°

Fig. 21. E. M. F. Curve with Com-
mutator

Fig. 22. Armature with Single Coil

Fig. 23. Two-Coil Armature

in parallel and while the voltage generated by revolving this winding
with two coils is no greater than with one coil, the current-carrying
capacity of the winding is doubled. The current generated by

410

Digitized by

Google

ELECTRICAL EQUIPMENT

this form of armature would still have the disadvantage, however,
of being pulsating. As in the case of the automobile motor, the
number of cylinders must be increased to make the power output

a continuous unbroken line, so
armature coils and their corre-
sponding commutator brushes
must be added that one set may
come into action before the other
"goes dead". By placing an
extra pair of coils on the arma-
ture, at right angles to the first,
as shown in Fig. 24, one set will
be in the position of maximum activity when the other is at the point
of least action. While this armature would produce a continuous
current, it would not be steady, having four pulsations per revolu-
tion, and it is consequently necessary to increase the number of
coils and commutator segments still further to generate a steady,
continuous current. This is what is done in practice.

A commutator consists of a number of copper bars or segments,
equal to the number of sections in the armature. These bars are
separated by sheets of insulating material, usually mica, and are

Fig. 24. Four-Coil Armature

Fig. 26. Sectional and End Views of a Commutator
CourUty of Horeelcsa Age

firmly held together by a clamping device consisting of a metal
sleeve with a head having its inner side undercut at an angle, a
washer similar in shape to the head of the sleeve, and a nut that

411

Digitized by

Google

38 ELECTRICAL EQUIPMENT

screws over the end of the sleeve, as shown in the left-hand or
sectional view of Fig. 25. The sleeve is surrounded by a bushing
of insulating material, and washers of the same material are placed
between the assembly of commutator bars and the two clamping heads.
Each bar is then completely insulated from every other bar and from
the clamping sleeve. Commutators are also made by pressing the
entire assembly of copper segments together, or molding them,
in insulating material (Bakelite), which thus forms the hub or
mounting of the commutator as well as the insulating material
between the segments. After assembling, the commutator is
turned down in a lathe to a true-running cylinder and then sand-
papered on its outer cylindrical surface to present a smooth bearing
surface for the brushes. At the inner end of the commutator
which is closest to the armature windings, the commutator bars
are provided with lugs as shown in the sectional view; these lugs
are slotted and the armature leads are soldered to them. At the
right, Fig. 25, is shown an end view of the same commutator.

From the repair man's point of view, the commutator is the
most important part of the generator or the motor, since it is one
of the first with whose shortcomings he makes acquaintance. Prac*
tically all lighting and starting motors now have their armature
shafts mounted on annular ball bearings, so that the commutator
and the brushes are the only parts that are subject to wear. If
the time devoted in the garage to the maintenance of automobile
electric systems were to be divided according to the units demanding
attention, the battery would naturally come first, brushes and
commutators next, then switches, regulating instruments, con-
nections, and wiring, about in the order named. After all of these
come, of course, burnt-out armatures or other internal derangements
which necessitate returning the units to the manufacturer; but
troubles of this nature are quite rare. While this list gives the
order of precedence, it has no bearing on the relative importance
of the troubles; with respect to the total time taken by each, the
battery is responsible for not far from 90 per cent, the commutator
for about 5 per cent, all other causes comprising the remaining 5
per cent.

Armature Windings. In the simple illustrations given to
show the method of generating e.m.f. in the armature and leading

412

Digitized by VjOOQlC

ELECTRICAL EQUIPMENT 39

the current to the external circuit, what is known as the ring type
of winding is shown. This is inefficient because half the length
of the conductor — the portion inside the ring — does not cut any
lines of force and hence does not aid in generating the current.
The design, moreover, does not lend itself to compactness, so that
it would not be adapted to automobile work even if there were no
objection to it on the score of inefficiency. A slotted type of arma-
ture core is very generally employed for the small generators and
starting motors used on automobiles and the wire is either wound
directly in the slots, or is "form wound'-', that is, the wire is placed
on a wooden form shaped to correspond to the position the coil will
take when in place on the armature. After winding the necessary
length of conductor on this foundation, the wire is taped together, and
varnished or impregnated with an insulating compound, and baked.

Owing to its high magnetic permeability, iron is universally
employed for the core of the armature, since the function of the
core is to carry the magnetic flux across from pole to pole of the
field magnets, as well as to form a foundation for the coils. How-
ever, when a mass of iron is rotated in the field of a magnet what
are known as "eddy currents" are set up in the metal itself, and
these prevent the inner parts of the mass from becoming magnetized
as rapidly as the outer and also cause the interior to retain its mag-
netism longer. As the efficiency of the generator depends upon
the rapidity with which the sections of the armature become mag-
netized and demagnetized as they revolve, the lag due to these eddy
currents is a detriment. To reduce this effect to the minimum,
the armature cores are always laminated, that is, built up of thin
disks of very soft iron or mild steel, these disks having the necessary
slots punched in them to accommodate the windings when assembled
on the shaft. The disks are insulated from one another either by
varnishing them or by inserting paper disks between them. They
are assembled on the shaft and are put together under considerable
pressure, various means being employed to hold them in place.
These disks are so thin that hundreds of them are required to make
an armature core only a few inches long, and when pressed together
in place they are to all intents and purposes a solid mass.

Armature winding, however, is something that is entirely
beyond the province of either the car owner or the repair man, no

413

Digitized by

Google

ELECTRICAL EQUIPMENT

6W4

matter how well equipped a shop he has. It is a job for the expert
in that particular line, and on the rare occasions when an armature
does go wrong, it should always be returned to the manufacturer,
if possible, if no^ to a shop making a
speciality of such work.

Field Magnets. In the foregoing
explanation of the generation of an
e.m.f. in a conductor when rotated in a
magnetic field and the leading out of
the current through a commutator, the
presence of the field has been assumed
and nothing has been said regarding
the method of providing it. The term
field is applied interchangeably to the
magnetic flux between the pole faces of
the field magnets and to the magnets
themselves, but it is more generally
understood to refer to the latter directly
and to the former by inference. There
are various methods of maintaining
the flux, usually described as "field magnet excitation", but only
two of them are applicable to the electric generators employed on
the automobile.

Permanent Field Used in Magneto. The simplest of these,
and the first to be designed, employed permanent magnets, from
which such a generator takes its name,
magneto. Fig. 26 is a diagrammatic rep-
resentation of an early form of the mag-
neto-generator. Since magnetism cannot
be maintained permanently at the high
flux-density or strength which can be
produced by an exciting coil fed by a
current, this method is only employed
in very small generators, as its bulk for
large powers would be excessive. Its
great advantage is its simplicity and constancy. The magneto-gener-
ator shown in Fig. 26, however, is designed to produce a continuous
current, and is not the type in general use on the automobile today.

Fig. 26. Diagram of Magneto

Fig. 27.

CourUty of HorteUt* Age

Sketch Showing Shape of
Armature Core

414

Digitized by

Google

ELECTRICAL EQUIPMENT

The type usually installed is made with a two-pole armature,
as shown by Fig. 27. This figure illustrates the core known as
a "shuttle" type because the wire is wound around the center of
the core in much the same manner as thread is put on a shuttle.
These cores are laminated as already described, in all well-built
magnetos. The space on the core is filled with a single coil of
comparatively coarse wire on the majority of magnetos, which
generate a low voltage current that is subsequently stepped up
through an outside transformer. In some instances, in what may be
termed the true high-tension type of magneto, there is a second wind-
ing of fine wire on the core so that the magneto generates a current

/f\/f\/f\

ill V m. .v.'rrsi»tK :•/. Jf t i\

A B C

Fig. 28. Diagrams Showing Distribution of Magnetic Flux for Various Positions
Courtesy of Uoraelesa Age

and steps it up without the aid of any outside devices. In either
case, one end of the winding is "grounded on the core", that is,
connected to it electrically, so that the core and other metal parts
of the machine form one side of the circuit, while the other end is
connected to a stud against which a spring-controlled carbon brush
bears, to collect the current. Detailed descriptions of various
types of magnetos are given later so that nothing further concerning
the construction need be added here.

Principle of Operation of Magneto. Under "Generator Prin-
ciples", the principle of the operation of the magneto has already
been explained, the method by which the rotation of the conductors
in the magnetic field generates an e.m.f. and a current is induced

115

Digitized by

Google

ELECTRICAL EQUIPMENT

in them. But as the actual operation of the magneto as designed
for ignition purposes is radically different from any other form of
generator, it is given here. If unrestricted, the armature of the
magneto will always assume the position shown at A, Fig. 28, and
considerable effort will be required to turn it from this position
as the magnetic flux through the armature is then a maximum.
When the armature is rotated a little over 90 degrees from this
horizontal position so that the armature poles leave the field poles,
as at B in the same figure, the flux decreases, and when in a vertical
position no lines of force pass through it. At this point, the direction

-Ois ft* volution Cf/f mature

Fig. 29. Curve of Primary E. M. F. in Magneto on

Open Circuit

Courtesy of Horseless Age

of the magnetic flux through the armature core reverses. Having
a two-pole armature, the magneto produces an alternating current
of one complete cycle per revolution, as shown by the curve, Fig.
29, which illustrates the electromotive force generated at the dif-
ferent positions in the rotation of the armature. The similarity
between this curve and the one generated by the elementary dynamo,
Fig. 17, will be noted. With the armature in the horizontal position
there is a dead point, the e.m.f. curve only starting as the pole
pieces of the armature begin to cut the edges of the field magnet
poles. It then rises very sharply to a peak, and as sharply drops

416

Digitized by

Google

ELECTRICAL EQUIPMENT

00000

^sr^

Fig. 30. Diagram Showing Series Generator

away to zero again, thus forming one-half cycle, which is then repeated
in the opposite direction. As the present discussion comprises

only an introduction to elemen-
tary principles and theories*
further details of construction
and operation of the magneto
are given later in the section on
"Ignition".

Self-Excited Fields. In a
machine of the magneto type, the
only method of varying the cur-
rent output is to vary the speed
of the armature, and it is there-
fore not well adapted to the
majority of uses for which a gen-
erator is employed. Conse-
quently, other methods of excit-
ing the fields have been developed, which may be roughly divided
into two classes: first, those separately excited, in which cur-
rent from an independent source is supplied to the field windings.
This is now practically restricted to large alternating-current gen-
erators and so need not be con-
sidered further here. Second,
self-excited fields, which are now
characteristic of all continuous
current generators. In this
method all or a part of the cur-
rent induced in the armature
windings is passed through the
field coils, the amount depend-
ing on the type of generator.

Series Generator. Where
the entire current output is util-
ized for this purpose, the dynamo
is of the series type, and a refer-
ence to the section on "Cir-
in connection with the illustration, Fig. 30, will make this
There is but a single circuit on such a dynamo and while it

i>i>i>i>i>

^Sr^

(<l

£)'

(

Fig. 31

cuits",
plain.

Diagram Showing Shunt- Wound
Generator

417

Digitized by

Google

ELECTRICAL EQUIPMENT

has the advantage of simplicity, it does not generate a current until
a fairly high speed is reached, or unless the resistance in the
external circuit is below a certain limit. It is also likely to have
its polarity reversed so that it is not fitted for charging storage
batteries. As the only series generators put into commercial use
have been for supplying arc lamps in series for street lighting,
they need not be considered further.

Shunt-Wound Generator. By winding the generator with two
circuits instead of one and giving that of the fields a relatively high
resistance as compared with the outside circuit on which the generator
is to work, a machine that is self-regulating within certain limits
is produced. As shown by Fig.
31, the main circuit of the gener-
ator is that through the arma-
ture with which the field wind-
ing is in shunt. The current
accordingly divides inversely as
the resistance and only a small
part of it flows through the field
coils, while the main output of
the generator flows through the
external circuit to light the lamps,
to charge a battery, or the like,
the resistance of this external
circuit being much less than that
of the fields. But in this type,
as well as in the simple series form, the e.m.f. generated varies more
or less with the load, and as the latter is constantly changing, it
is necessary to provide some means of varying the e.m.f. gen-
erated to suit the load, in other words, to make the generator
self-regulating. Of the several available methods of doing this,
the only one applicable to the small direct-current generators used
in automobile lighting and starting systems, is that of varying the
magnetic flux through the armature.

Compound-Wound Generator. There are also several methods
of effecting this variation of the magnetic flux, but the most advan-
tageous and consequently the most generally used, is to vary the
amount of current in the energizing coils on the field magnets.

Fig. 32.

Diagram Showing Compouod-
Wound Generator

418

Digitized by

Google

ELECTRICAL EQUIPMENT 45

By adding to the shunt winding a few turns of heavy wire in series
with the armature so that all the current passes through them, the
magnetic flux may be made to increase with the load as it is directly
affected by the current demanded by the latter. This combination
of the shunt and series is termed a compound winding, and the
usual method of affecting it is shown by Fig. 32. Such a machine

C D

Fig. 33. Forms of Field Frames

is called a compound generator, and is sometimes used for lighting
and for charging the storage batteries of automobiles.

In view of the great range of speed variation required of the
automobile motor, the series wiring is sometimes reversed so as
to act against the shunt instead of with it, in order to prevent an
excessive amount of flux and a current that would be dangerous
to the windings themselves due to a very high speed. The compound

419

Digitized by

Google

46 ELECTRICAL EQUIPMENT

winding then opposes the shunt-winding and is termed a bucking-
coil or winding. This is referred to later in connection with the
discussion of methods of regulating the generator on the automobile.

Forms of Field Magnets, For greater simplicity, all of the
illustrations shown in connection with the explanation of the various
types of generators are of the old bipolar type in a form long since
obsolete. The field frame, as it is designated may, however, take
a number of different forms depending entirely upon the designer's
conception of what best meets the requirements of ample power
in the minimum of space and with the minimum weight. Fig.
33 shows some typical forms of field frames in general use on auto-
mobile generators, and it will be noted that in addition to providing
a magnetic circuit the field frame also serves to enclose the windings.
These are known as "ironclad" types from the fact that all parts
are thoroughly enclosed and protected. The arrows in each case
indicate tbe paths of the magnetic circuits, the number of the cir-
cuits varying with the number of pole pieces. The form at A has
two opposed poles, each of which is designed to carry an exciting
coil or winding. This is a bipolar machine. Field frame B is
also of the bipolar type but only one pole carries an exciting winding,
the other being known as a consequent pole. In both of these
field frames, it will be noted that the magnetic circuits are long,
which adds to the magnetic reluctance and tends to decrease the
efficiency. To overcome this, multipolar types of field frames
are very generally employed. One of these, with two wound or
salient poles and two consequent poles, is shown at D, the extra
poles making four short instead of two long magnetic circuits.
C is a multipolar type with four salient poles.

Brushes. Brushes serve to conduct the current generated
by the armature to the outer circuit and to the field coils in order
that the excitation of the latter may correspond with the demand
upon the generator. The brushes originally employed were strips
of copper which bore on the commutator; as generators increased
in size these brushes were built up of thin laminations of copper.
Plain copper brushes in any form, however, cause an excessive
amount of sparking which is ruinous to the smooth surface and
true running of a commutator. Built-up copper gauze brushes
were then adopted, and they were fitted to bear against the com-

420

Digitized by

Google

ELECTRICAL EQUIPMENT 47

mutator. Though an improvement, these did not meet all the
requirements and were in turn superseded by carbon brushes,
which are now practically universal. The carbon brushes usually
bear directly against the face of the commutator, either through
a blunt, squared end, or one that is slightly beveled. The brush
holders are generally attached to rocker rings, which allow adjust-
ments to prevent sparking; in these holders are small helical springs
under compression, which serve to press the brush against the commu-
tator. Ordinarily, the brushes are composed of a uniformly smooth
and homogeneous compound of carbon that soon acquires a glazed
surface at its bearing end and wears indefinitely without requiring
any attention, but at times a gritty brush will be found. Such a
brush scratches the commutator surface, wears unevenly, and is
generally a source of trouble.

Badly worn commutators frequently result from the use of
improper brushes, or too heavy a spring pressure — also from too
light a spring pressure. The manufacturer has found out by experi-
ment and study just what character of brush is best adapted to
his particular generator or starting motor and also the exact amount
of spring pressure that is necessary to insure the best results. Con-
sequently, much trouble will be avoided if brushes are replaced
only with those supplied by the manufacturer of that particular
machine, in connection with the brush springs that were designed
for it. There are electrical as well as mechanical reasons for this,
since both the resistance and current-carrying capacity of carbon
brushes vary. This has been taken into consideration by the man-
ufacturer who has provided a brush especially adapted to his
machine.

ELECTRIC MOTOR PRINCIPLES

Theory of Operation. A machine that is designed to convert
mechanical into electrical energy or the reverse, is known as a
dynamo-electric machine. When its armature is rotated by an
external source of power, such as a steam engine, hydraulic turbine,
or gasoline engine, it is a generator. By sending a current through
it from another generator or a battery it converts electrical into
mechanical energy and is a motor. It is evident, then, that a
generator and a motor are fundamentally one and the same thing,
and that by a reversal of the conditions one unit may be made to

421

Digitized by

Google

48 ELECTRICAL EQUIPMENT

serve both purposes. It will naturally depend upon how closely
these purposes approach each other so far as their operating con-
ditions are concerned, whether it will be practical to employ the
same machine for both. In practice, operating conditions rarely
approximate and so before the advent of the single-unit starting-
and-lighting system on automobiles the use of the same machine
for both generating current and converting it into mechanical
energy was practically unknown. Space considerations were the
chief factor which led to the development of the single system,
as the demands on the machine for charging the battery and starting
the engine are radically different.

How Rotation Is Produced. The operation of an electric motor
will be clear if the essentials of a dynamo-electric machine and their
relations are kept in mind. There is, first, the magnetic field and
its poles — two or any multiple thereof, though for space reasons
more than four poles are seldom used in starting motors; then the
armature, which must also have an even number of poles corre-
sponding to the number of segments in the commutator. Each
separate coil in the armature winding magnetizes that section of
the armature core on which it is wound, when the current passes
through it, as its terminals, connected to different segments on the
commutator, come under the brushes. In an electric motor having
either two or four field poles, and eight, twelve, or sixteen armature
poles, it is apparent that every few degrees in the revolution of
the armature an oppositely disposed set of its poles is either just
approaching or just leaving the magnetic field of two of the field
poles. Bearing in mind that like poles repel one another and that
unlike poles attract, and that the polarity of both the fields and
the armature coils is constantly being alternated by the commutator,
we see that each section of the armature is constantly being attracted
toward and repelled from the field poles.

The fundamental law just stated can be easily illustrated by
taking two common horseshoe magnets, such as can be bought
for a few cents. Placing their north and south poles together
it will be found that they have no attraction for each other and
cannot be made to adhere in this relation. If they had sufficient
force they would actually move apart when placed on a smooth
surface in this position. But if one of the magnets is turned around

422

Digitized by

Google

ELECTRICAL EQUIPMENT 49

so as to bring the north and south poles of the two opposite each
other, the magnets will be immediately attracted and will hold
together to the full extent of their force.

What may be called one cycle of the operation of an electric
motor may be described as follows: the motor turns clockwise;
it is of the bipolar type, that is, it has two field poles; and there are
eight coils on the armature. At the moment assumed, the left
field pole is the north, and the right south; consequently, the section
of the armature just entering the field is of opposite polarity, pre-
senting a south pole to the north pole of the field and a north pole
to the south pole of the latter. The armature is therefore strongly
attracted. This attraction is maintained by the current in the
windings continuing in the same direction until the magnetic attrac-
tion reaches a maximum, at which point the stationary and moving
poles are practically opposite each other. Unless a change occurred
just at that point the armature would be held stationary and could
be turned from it only by the expenditure of considerable force,
that is, assuming that the field did not lose its exciting current.
(This may be observed on a small scale by attempting to revolve
the armature of a magneto by turning its shaft by hand.) But
either at that point, or just before it is reached, the revolution of
the armature brings a different set of commutator bars under the
brushes and the direction of the current is reversed in that particular
winding and with it the polarity of the armature poles. Instead
of being mutually attracted the armature and field poles become
mutually repellent. In brief, the armature is first pulled and then
pushed around in the same direction by reason of the force exerted
both by the field magnets and by its own magnets. The passing
of one section of the armature through this change as it enters
and leaves the zone of influence of a pair of pole pieces may be said
to constitute a cycle of its operation, by analogy with alternating-
current generation. The cycles are repeated as many times per
revolution as there are coils on the armature and the number of
coils miltiplied by the speed will give the number of changes per
minute. For example, in a motor assumed to have eight armature
coils, as in the present instance, there would be, at a speed of 1,000
r.p.m., 16,000 changes per minute, which makes clear the reason
for the very smooth pull or torque that an electric motor exerts.

423

Digitized by

Google

50 ELECTRICAL EQUIPMENT

Counter E.M.F. Though being rotated by means of current
obtained from an external source of power, it is apparent that the
motor armature in revolving its coils in the magnetic field is fulfilling
the conditions previously mentioned as necessary for the generation
of an e.m.f. Experiment shows that the voltage and current thus
generated are in an opposite direction to that which is operating
the motor. It is accordingly termed a counter e.m.f. as it opposes
the operating current. This, together with the fact that the resist-
ance of copper increases with its temperature and that the armature
becomes warmer as it runs, explains why the resistance of a motor
is apparently so much greater when running than when standing
idle. The counter e.m.f. approaches in value that of the line e.m .f ., or
voltage at which current is being supplied to the motor. It can,
of course, never quite equal the latter for in that case no current
would flow. The two opposing e.m.f.'s would equalize each other;
there would be no difference of potential.

Types of Motors. Being the counterparts of electric generators,
electric motors differ in type according to their windings in the same
manner as already explained for generators. The plain series-wound
motor is nothing more or less than the simple series-wound generator
to which reference has already been made; the shunt and compound
motors likewise correspond to the shunt and compound generators.
But while the series-wound generator was of extremely limited
application and has long since become obsolete, the series-wound
motor possesses certain characteristics which make it very generally
used. It is practically the only type employed for starting service
on the automobile, and it is also in almost universal use for railway
service. The reasons for this are its very heavy starting torque
which increases as the speed of the motor decreases, the quick drop
in the current required as the motor attains speed, and its liberal
overload capacity. It is essentially a variable speed motor, and,
just as the plain series-wound generator delivers a current varying
with the speed at which it is driven, so the speed of the motor changes
in proportion to the load. These are characteristics which make
it valuable for use both as a starting motor for the gasoline engine,
and for a driving motor on the electric automobile, though in the
latter case it is seldom a simple series-wound type. As its speed
is inversely proportional to the load, however, it tends to race when

424

Digitized by

Google

ELECTRICAL EQUIPMENT 51

the load is light; in other words, it will "run away" if the load is
suddenly removed, as in declutching from the automobile engine
after starting the latter, unless the current is instantly shut off or
very much reduced. This is provided for, as will be explained in
detail later in connection with the various systems.

Shunt motors and compound-wound motors are the same as
their counterparts, the generators of the same types, but as they are
not used in this connection, no further reference need be made to
them here.

Dynamotors. As the term suggests, this is a combination of
the generator or dynamo and the electric motor, and it is a hybrid

Fig. 34. Dynamotor (Motor-Generator) of the Delco System

for which the automobile starting system has been responsible.
It is frequently mistermed a "motor-generator" and while its assump-
tion of the two r61es may justify the name, the use of the term is
misleading as it becomes confused with th ; motor-generators
employed for converting alternating into direct current. The latter
consist of an a-c. motor on one end of a shaft and a d-c. generator
on the other end of the same shaft. The two units are distinct
except for their connection, whereas a dynamotor is a single unit
comprising both generator and motor, and it can perform only
one of these functions at one time. A motor-generator, such as is
used in garages for transforming alternating into direct current
for charging storage batteries, must carry on both functions at

425

Digitized by

Google

ELECTRICAL EQUIPMENT

426

Digitized by

Google

ELECTRICAL EQUIPMENT 53

the same time in order to operate. That is, the a-c. motor must
run as a motor in order to drive the d-c. generator and cause it
to generate a direct current. Hence, the term motor-generator
as applied to the single-unit type of electric starting system for an
automobile is not in accordance with the accepted meaning of the
words and is likely to be confusing.

A typical example of the dynamotor is to be found in the Delco
single-unit system, illustrated in Fig. 34. This is really the windings
of two radically different machines, a shunt-wound generator and
a series-wound motor, placed on the same armature core and field
p3les. As will be noted, the terminals of the two sets of windings
on the armature are brought out in different directions and two

commutators are employed, that at the
right-hand end being for the generator
windings, and that at the left for the
motor. The method of winding the
armature is illustrated by Fig. 35, which
shows the generator and motor wind-
ings projected on a plane. In the pre-
ceding illustration the detail at the left
shows the gearing and starting connec-
tion for coupling the starting motor with
the flywheel of the engine, the one at
the right an ignition distributor for the
Kg. 36. Typical Dry Battery high-ten sion current. Both of these are

later referred to at greater length.
Batteries. The only other method known for generating a con-
tinuous, direct current is by means of chemical reactions in what are
known as primary cells. With the exception of the so-called dry cell,
a description of these and their workings could be of only historic
interest and is accordingly omitted here. As no chemical reaction
could take place in perfectly dry substances this part of the name
is used simply to distinguish such cells from those using a liquid
solution. The dry cell is a zinc-carbon couple, Fig. 36, the zinc
acting as the container while the carbon is a heavy rod packed in
manganese dioxide, together with some moisture-absorbing material.
On the contents of the zinc container as thus filled is poured a
solution of sal ammoniac and water which forms the active solution

427

Digitized by

Google

54 ELECTRICAL EQUIPMENT

of the battery. The cell is sealed at the top to prevent evaporation,
since, when the cell does actually become as dry inside as it is out-
side it is no longer of any use. Some of its other characteristics are
mentioned under "Ignition", Part II.

The storage battery or accumulator does not generate a current
in any sense of the word. By means of a much more complicated
chemical reaction than that of the primary cell it absorbs a charge
of electricity. Upon the completion of the circuit of a storage
cell with a suitable load or resistance, such as driving a motor or
lighting a lamp, a reversal of this chemical process takes place and
the battery redelivers a part of the current which it has previously
absorbed. Full details of the characteristics, construction, and
working of the storage battery are given in the article on "Electric
Automobiles". The storage battery and the dry cell are the only
two forms of battery employed on the automobile so that no mention
of the other types is necessary, particularly as all but very few of
'them are practically obsolete.

SUMMARY OF ELECTRICAL PRINCIPLES
QENERAL PRINCIPLES

The importance of a knowledge of the fundamental principles
of electricity and of its characteristics to the man who wishes to
familiarize himself with the electrical apparatus on the automobile
to the point where he can readily diagnose and remedy its ills has
already been dwelt upon. To bring these out more clearly and make
them easier to memorize, they are repeated here in the form of a
brief r6sum6 in questions and answers.

Q. What is electrical pressure, and to what may it be com-
pared?

A. Electrical pressure is electromotive force, usually termed
e.m.f., or voltage, also potential, and may be likened to water under
pressure in a pipe or to compressed air in a container.

Q. Of what does this electrical pressure consist, and how
is it measured?

A. It is represented by the difference of potential between two
points in a circuit, and it is measured in volts.

Q. What does the unit volt represent?

Digitized by VjOOQIC

ELECTRICAL EQUIPMENT 55

A. The volt is the amount of e.m.f. required to force a current
of one ampere through a resistance of one ohm.

Q. What is the ampere?

A. It is the unit of current flow.

Q. What is the ohm?

A. The unit of resistance represented by a length of wire
that will pass one ampere under a pressure of one volt.

Q. In what unit is the volume of current flow measured?

A. In the coulomb, which is the equivalent of one ampere
per second.

Q. Are the factors of electrical quantity, flow, and pressure
related, and how?

A. They are all closely related, and their relation is governed
by the factor of resistance.

Q. What is resistance, and of what may it consist?

A. Any element which tends to retard the flow of the current
is resistance. It may consist of the wire of the circuit itself; the
windings of different apparatus in the circuit, such as an induction
coil or a motor; the filament of a lamp; a switch; or the like.

Q. Are these the only forms that resistance takes?

A. No. Poor joints in wires, dirty and loose connections,
dirty switch blades, all produce increased resistance in the circuit.
These are undesirable increases in the resistance. In addition to
these, there are special resistances intentionally inserted in the
circuit to serve a definite purpose. These are known as rheostats,
resistance coils, windings, or grids, according to the form they
take.

Q. Why is it desirable to keep the resistance of the circuit,
outside of that produced by the apparatus itself, at a minimum?

A. Because any resistance other than that interposed by the
windings of the motor, the filaments of the lamps, or other useful
apparatus in the circuit, not only means waste current, but also
prevents the full amount of current required from reaching the
desired points.

Q. How does this waste occur?

A. In a poor joint, a loose connection, or a dirty switch blade,
the current is dissipated as heat and accordingly represents that much
energy passing off into the air.

429

Digitized by

Google

56 ELECTRICAL EQUIPMENT

Q. Can undesirable resistance be interposed in a circuit in any
ways other than those already mentioned?

A. Yes, by the use of wire too small to carry the amount of
current required by the apparatus.

Q. What is the effect of using wires too small for the current?

A. The wires waste a great deal of the current in heat and, if
much too small for the purpose, are likely to become overheated to
a point at which they will burn the insulation off or to actually become
fused by the current.

Q. What determines the voltage in an electrical circuit?

A. The potential, or voltage, of the source of supply, such as
a storage battery, in which case the voltage will be constant less the
drop caused by the resistance of the circuit; or, in the case of a light-
ing generator, it will depend upon the design of the latter (winding,
etc.) and the speed at which it is running.

Q. How may the voltage be varied?

A. In the case of a battery, by varying the number of cells, each
cell of a storage battery giving approximately 2 volts. In a gen-
erator, by varying the windings of the field and the armature and by
increasing or decreasing the speed at which it runs. On a circuit
having a higher voltage than desired, by the insertion of an amount
of resistance calculated to give the drop required.

Q. Can lamps of a certain voltage be burned on a circuit having
a higher voltage?

A. Not if inserted directly in such a circuit. For example, the
standard 6-volt lamp cannot be used directly on a 6- or a 12-cell
storage-battery circuit as employed for the lighting and starting
systems of many cars. The filament would immediately burn out,
as its thickness is calculated to a nicety to become incandescent when
current of the voltage for which it is designed is passed through it,
and anything in excess of this voltage will fuse the wire.

Q. How can lamps of lower voltage be used on such circuits
without the employment of a wasteful resistance to cut the voltage
down?

A. By cutting down the number of cells employed for the light-
ing, as, for example, where 12 cells are used to operate the start-
ing motor, the battery is divided into four groups of 3 cells each
for the lighting, these groups delivering current at 6 volts, while

Digitized by VjOOQIC

ELECTRICAL EQUIPMENT 57

the complete battery has a potential of 24 volts. This is termed
putting the battery into series-multiple connection, which is explained
further under the head of "Circuits".

Q. When the voltage is lower than that required by the lamp,
what happens?

A. The lamp filament will give only a dull red glow with a volt-
age drop of but 20 per cent or less of the total, since there is insufficient
potential to cause the current to bring the filament wire to
incandescence.

Q. Is the insertion of any apparatus, such as lamps, a motor,
etc., in a circuit having a voltage higher than that for which they are
designed likely to damage them?

A. Yes, it will burn them out if, for instance, 110-volt lamps
or motors are connected to 220-volt current, or 6-volt lamps put on a
12-volt circuit.

Q. Does the opposite also hold true?

A. No. The apparatus will merely fail to function properly if
put on a circuit of a voltage lower than that for which it is designed.

OHM'S LAW

Q. What is Ohm's law?

A. It is the basis of all computations concerning the flow of
an electric current. It is stated as current equals voltage divided by
resistance and may be transposed to find any of the three factors, as,
resistance equals voltage divided by current, so that, given any two of the
factors, the third may be readily determined.

Q. How is the power equivalent of an electric current
expressed?

A. Power equals current times voltage, the product being
watts, as one volt times one ampere equals one watt.

Q. How many watts are there in a horsepower?

A. 746. Electrical horsepower, however, is usually figured in
kilowatts, or units of one thousand watts, generally abbreviated to KW.

Q. Given a 6=volt storage battery fully charged and a circuit
including a starting motor, the total resistance of which (idle) is .1
ohm, how much current will pass through the motor?

A. As current equals voltage divided by resistance, we have
6 -7- .1 = 60 amperes.

4^1

Google

58 ELECTRICAL EQUIPMENT

Q. If, instead of a heavy stranded cable between the battery
and motor, we substitute a fine wire having a resistance of 10 ohms,
how much current will pass?

A. Only .6 ampere.

Q. What would happen if a very small wire were employed to
connect the starting motor with the battery?

A. Not sufficient current would reach the motor to operate it,
and the wire would probably be fused by the heating effect of the
heavy current.

Q. If one horsepower be required to turn the engine over at
100 r.p.m., and the car is equipped with a 6-volt battery, how many
amperes will be necessary to start?

A. As power divided by voltage equals current, 746-7-6 = 124$
amperes.

Q. How is the power equivalent usually expressed?

A. Power equals current times voltage.

Q. As the voltage is one of the chief determining factors, what
effect does doubling it have?

A. Reduces by one-half the amount of current required, exactly
the same as doubling the pressure of a steam boiler reduces corre-
spondingly the volume of steam necessary to perform the same
amount of work.

Q. If the voltage be cut in half, what will be necessary to per-
form the same amount of work?

A. The number of amperes, or amount of current, must be

doubled.

MAQNETISM

Q. What is magnetism?

A. It actually is electricity in another form and is evidenced
by the attraction or repulsion that one magnet exerts on another,
or that any piece of magnetized metal has for objects of steel or iron.

Q. How is this relation between magnetism and electricity
shown?

A. By the fact that they are interchangeable. By passing a
current of electricity through a coil surrounding an iron or steel bar, it
becomes magnetic; upon moving a magnetized piece of metal close
to a coil of wire, a current of electricity is induced in the wire.

Q. What is meant by the polarity of a magnet?

Digitized by VjOOQIC

ELECTRICAL EQUIPMENT 50

A. Upon being magnetized, a bar of steel will attract other
pieces of metal (iron or steel) indiscriminately, but upon being
brought close to another magnet, it will display an attraction at
one end and a repulsion at the other for the second magnet. In
other words, the magnetic attraction at both ends is not the same.
These ends are termed the poles, one north and the other south,
by analogy with the compass which is merely a magnetized needle
having a natural tendency to point north and south.

Q. What other characteristics do the poles of a magnet display?

A. They show that the force of the magnet is practically
concentrated at these poles, as the magnetic attraction is very
much less at any other part of the bar.

Q. What is the law of magnetic attraction and repulsion?

A. Like poles repel one another and unlike poles attract. In
other words, if a bar magnet be suspended, and the north pole of
a second magnet be held close to the north pole of the suspended
magnet, the latter will swing away; if the south pole of the second
magnet be approached to the north pole of the suspended magnet,
the latter will swing toward the former until they touch.

Q. How does the force of this attraction or repulsion vary?

A. Inversely as the square of the distance, i.e., separating
the poles by twice the distance reduces the force acting between
them to one-fourth its value. For example, if two magnets exhibit
a strong attraction for each other at a distance of one-half inch,
the attraction will be four times stronger when they are separated
by only one-fourth inch.

Q. What are the chief magnetic substances?

A. Iron and steel.

Q. What is meant by the magnetic field?

A. The space immediately surrounding the poles and at which
the magnetic force is most plainly apparent, as shown by the experi-
ments with filings which graphically illustrate the field of influence
of the magnet, and from which the term in question originates.

Q. What is a magnetic circuit?

A. The path followed by the magnetic flux, or flow, from one
pole to the other.

Q. What analogy is there between the poles of a magnet
and the flow of a current in an electric circuit?

433

Digitized by

Google

60 ELECTRICAL EQUIPMENT

A. The current is said to flow from the positive, or north, pole
of a battery or generator, to the negative, or south, pole to complete
the circuit, exactly as the lines of force in a magnet flow to complete
the magnetic circuit.

Q. How can the polarity of a current flowing in a wire be deter-
mined by a simple experiment?

A. Hold a small pocket compass close to the wire. If the needle
of the compass is attracted at its north pole to the wire, the current
flowing in the latter is negative (south pole), as unlike poles attract,
and vice versa. This will be true only when a direct current is flowing
in the wire, since an alternating current, as the term indicates, alter-
nates in polarity with every cycle.

Q. What are lines of force?

A. The invisible flow of magnetic influence from the north to
the south pole of a magnet or about any conductor carrying an
electric current.

Q. What is a solenoid?

A. A hollow coil of wire through which a current may be passed
to produce a magnetic field.

Q. What is the difference between a permanent magnet and an
electromagnet?

A. When a piece of hard steel has been magnetized, either by
being rubbed on another magnet or by being placed in a solenoid
through which a current is passed, the steel retains a large percentage
of its magnetism when removed from this magnetic field and is said
to be a permanent magnet. An electro magnet consists of a soft iron
or steel core on which a coil of wire is wound. When a current passes
through the wire, the coil becomes strongly magnetic, but when the
current ceases, the magnetism does likewise.

Q. When a bar of iron is placed partly in the coil of a solenoid
through the winding of which a current is passed, what takes place?

A. The bar is strongly attracted to the center of the coil and
held there.

Q. How is this principle taken advantage of in electric starting
and lighting systems on the automobile?

A. It is employed for the operation of electromagnetic switches
for the starting motor, and it is also the principle upon which the
electromagnetic gear shift depends for its operation.

434

Digitized by CjOOQIC

ELECTRICAL EQUIPMENT 61

Q. What effect has the insertion of an iron core in a solenoid?

A. It greatly increases the flow of magnetism through the sole-
noid, with the same amount of current passing through the winding
of the latter.

Q. What effect has reversing the direction in which the current
is passed through the winding of a solenoid?

A. It reverses the polarity of the latter so that if the core were a
bar of hard steel, it would be drawn into the opening of the solenoid
with the current in one direction, and expelled from it when the cur-
rent was reversed.

Q. What bearing have the principles of magnetic attraction and
repulsion and of magnetic polarity on electric generator and motor
operation?

A. They are the fundamental principles upon which the opera-
tion of all electric generators and motors are based.

INDUCTION

Q. What is the principle of electric induction?

A. If a circuit carrying an electric current be opened and closed
quickly in the case of direct current, and a coil of wire be held close
to this circuit, a current will be induced in the coil. If the latter be
wound on an iron core, the induced current will be very much stronger,
and if both the active circuit and the coil are on the same magnetic
core, the maximum inductive effect will be produced. The latter is,
in effect, a transformer, and if an alternating current be sent through
the first circuit, or coil, there is no need to make and break the circuit
as where the current is direct.

Q. Why will a transformer not operate on direct current without
making and breaking the circuit constantly?

A. It is necessary to magnetize and demagnetize the core, or,
where there is no core, to produce a magnetic field and then destroy
it, in order to produce an inductive effect.

Q. Why will it operate on alternating current without making
and breaking the circuit?

A. Because the alternating current intermittently rises to its
maximum in one direction, then drops to zero and rises to its maximum
in the opposite direction, that is, the direction or the polarity of the
current changes with every cycle. The transformer core is accord-

435

Digitized by

Google

62 ELECTRICAL EQUIPMENT

ingly magnetized to full strength with a certain polarity, is then
demagnetized and again remagnetized with the opposite polarity,
and it is this rise and fall in the strength of the magnetic field from
zero to maximum, first in one direction and then in the other, that
causes the inductive effect.

Q. What is a cycle?

A. It consists of one alternation from zero to maximum in one
direction, back to zero and then to the maximum in the opposite
direction, and back again to zero. The ordinary house-lighting
supply current is 60 cycles, i.e., it alternates 60 times per second, or
3600 times per minute. It is owing to this extreme rapidity in alterna-
tion that no flickering is apparent in an incandescent lamp fed by
alternating current.

Q. Where alternating current is not available, how can a trans-
former be operated?

A. By making and breaking the circuit at a high rate of speed,
as with a vibrator used on automobile induction coils.

Q. In general, why is no vibrator necessary on a coil when
fed with current from the magneto?

A. Because the magneto supplies an alternating current.

Q. On the so-called dual system of ignition, the same coil with-
out any vibrator is used with both the battery and magneto as a source
of current. How is this effected?

A. The circuit breaker, or interrupter, of the magneto takes the
place of the vibrator when the battery is used for starting, while
the alternating current from the magneto operates the induction coil,
or transformer, when the engine is running on the magneto.

Q. What relation does the induced current bear to the current
from the source of supply?

A. This depends upon the transformer and the purpose for
which it is intended. On the automobile where it is desired to raise
the current to a high voltage to enable it to bridge the gap of the spark
plugs, the transformer is known as a step-up type, i.e., it takes current
at a low voltage and transforms it to one of high voltage, or tension.
The original, or primary, current passes through a winding of a com-
paratively small number of turns of coarse wire on a core of soft iron
wires. Directly over this winding is a second one consisting of a great
number of turns of very fine wire. This is known as the secondary

Digitized by VjOOQlC

ELECTRICAL EQUIPMENT 63

winding,* axA the current induced in it is termed a secondary current.
The voltage of this secondary current depends upon the voltage of the
source of supply and the proportion that the number of turns in the
secondary winding bears to that of the primary winding.

Q. Is the transformer used in any other form or type on the
automobile?

A. In the so-called true high-tension type of magneto, the trans-
former is made integral with the armature, the fine wire, or secondary
winding, being placed directly over the coarser winding that serves
to generate the current. The step-up is the only type of transformer
used on the automobile.

CONDUCTORS

Q. Do materials differ greatly in their ability to conduct elec-
tricity, and which are the most efficient in this respect?

A. They vary all the way from absolute insulators to those
metals which will pass the electric current with the minimum resist-
ance, such as silver, copper, and aluminum.

Q. Do the characteristics of a material affect its current-con-
ducting ability?

A. Very greatly. The harder copper is, the poorer its conduc-
tivity, and this is likewise the case with steel.

Q. Name the different materials in the order of their current-
conducting ability.

A. Silver in pure state, soft copper, brass, aluminum, iron, steel,
carbon, German silver, etc. ; also water, depending upon how alkaline
or acid it is.

Q. Is German silver a good conductor?

A. No. It is known as high-resistance conductor and is accord-
ingly used chiefly for winding resistances and not for the wires of a
circuit.

Q. What are some good insulators?

A. Wood, glass, resin, paraffin wax, silk, cotton, asbestos, rub-
ber, and similar mineral or vegetable substances.

Q. Are they always equally good insulators, regardless of their
condition?

A. They are efficient as insulators only when dry. The pres-
ence of moisture on any of them affords a path for the current to
cross them.

437

Digitized by

Google

64 ELECTRICAL EQUIPMENT

Q. What effect on the ability of the conductor to carry a current
has the amount of material used?

A. The resistance is increased with a decrease in size and is also
increased directly as the length of the conductor.

Q. Where, for mechanical or other reasons, it is not practical
to use copper or aluminum, how can an equally efficient conductor
of some other material be provided?

A. By increasing the amount of material employed in the same
proportion that its conductivity bears to that of copper. For
example, assuming that steel is only one-thirtieth as good a conductor
as copper, thirty times as much of it must be employed to give the
same conductivity.

Q. Give an example of this?

A. The single-wire system of connecting the starting and light-
ing outfit on an automobile. A small copper cable forms one side of
the circuit, while the entire chassis forms the other. The ordinary
trolley-road circuit is another, the small overhead wire forming one
side of the circuit, and the rails on which the car runs, the other.

Q. Name some of the materials which are employed for their
high resistance to the current.

A. German silver, iron wire, cast iron in the form of grids of
small cross-section, and carbon. Very fine copper w T ire is also
employed where the resistance desired is not very great, and space
considerations permit its employment.

Q. What is meant by the "specific conductivity" of a material?

A. Its ability to conduct the current as compared with that of
pure silver which has a specific conductivity of one.

Q. Does this ability of a conductor to convey the current vary
particularly with a great increase in voltage?

A. Yes. The so-called high-tension current which has been
stepped-up in a transformer from the 6-volt potential of the 3-cell
storage battery to many thousand volts for ignition purposes will
cross surfaces and penetrate materials that are perfect insulators to
the low-tension current. For example, the high-tension current will
leak across a moist wooden surface or it will sometimes puncture the
one-fourth inch of rubber and cotton insulation of the secondary cable.

Q. What is one of the chief effects of transforming a current at
a low voltage to one of high potential?

Digitized by VjOOQlC

ELECTRICAL EQUIPMENT 65

A. It enables the current to leap an air gap, the width of which
is proportioned to the voltage itself. The greater the voltage the
greater the width of the gap it will jump. This is the principle on
which the spark plug is based.

HIOH-TENSION CURRENTS

Q. When a current of 2 amperes at 6 volts, such as would be
consumed by the ordinary ignition coil from a storage battery, is
transformed to a high potential, is the amount Of current still the
same? In other words, can 2 amperes at 6 volts be transformed or
stepped-up to 2 amperes at 10,000 volts?

A. No. The current decreases as the voltage increases. For
example, to make the comparison more clear, consider a current of
10 amperes at 100 volts. This is passed through a step-up trans-
former, of which the ignition coil is a type, and is given a potential ol
1000 volts. The current, however, would then be 1 ampere, that is,
the current decreases in the same proportion that the voltage is
increased. The opposite is also true. By passing this current of 1
ampere at 1000 volts through a step-down transformer, it may be
converted into a current of 100 amperes at 10 volts. It will be noted
that the product of volts times amperes in any of the above instances
cited, or of any possible combinations that can be made, is always the
same. In other words, a certain amount of energy is sent through the
transformer, and the same amount, barring losses due to the trans-
formation process itself, is taken out.

Q. Is there any mechanical analogue of this process of trans-
forming a current up or down to impress upon it a greater or lesser
potential?

A. There is nothing in mechanics that corresponds exactly to
this peculiar property of electricity. The resulting change in the
form in which the energy is applicable as a result, however, may
readily be compared with mechanical standards. For example,
we may have in a very small boiler, a pressure of 1000 pounds to the
square inch, but a volume of only one cubic foot of steam. This
small amount at its high pressure represents the equivalent in energy
of 10 cubic feet of steam at a pressure of 100 pounds.

Q. What is the object of stepping the current up to such high
voltages?

439

Digitized by

Google

66 ELECTRICAL EQUIPMENT

A. On the automobile, simply to enable it to jump the gap of
the spark plug and fire the charge. In ordinary commercial service,
to permit of sending it long distances with a minimum expenditure
for copper wire and a minimum loss in the amount of energy
transmitted.

CIRCUITS

Q. What is meant by an electric circuit?

A. The path by which the electrical energy, or current, is said
to flow from and return to its source.

Q. Is a circuit absolutely necessary in order to permit of utiliz-
ing electricity?

A. Unless there is a circuit or complete path for the current,
it does not flow.

Q. Must a .circuit be comprised completely of wires leading
from, and returning to, the source, such as the battery or
generator?

A. No, it is not necessary that wire be used for both sides of
the circuit. One side or the other may be composed of a ground,
such as the tracks of a trolley system, the overhead wire consti-
tuting the other side of the circuit, or in the case of a single-wire
lighting and starting system in which one cable is employed to con-
duct the current from the battery to the starting motor and lights,
and the chassis itself forms the ground return for both.

Q. How many forms of circuits are there in general use?

A. Three: the series, the multiple, and the series -multiple.
In the first, all apparatus in the circuit is in series. That is, all the
current from the source must pass through each instrument or light
in turn to complete the circuit. In the multiple type of circuit,
every instrument or light on it is independent of all the others.
Lights may be turned on or off, motors started or stopped, without
interfering in any way with any of the others. As its name indicates,
the series-multiple is a combination of the two forms of circuits. For
example, in using incandescent lamps to cut down the current for
charging a storage battery from the lighting mains, the lamps them-
selves are in multiple, but the whole bank of lamps is in series with
the storage battery. See illustration on charging storage battery
direct from lighting mains.

Digitized by VjOOQIC

ELECTRICAL EQUIPMENT 07

Q. Which of these forms of circuit is in most general use on the
automobile?

A. All three will be found on practically every car equipped
with a starting and a lighting system. For instance, the starting
motor is operated in series with the battery, while the lamps are wired
in multiple for the side and head lights, and the speedometer and tail
light are wired in series as a branch of the multiple-lighting circuit,
thus giving a series-multiple circuit. The ignition distributor, coil,
and battery are in series.

Q. What is meant by a grounded circuit?

A. This is ordinarily used to indicate that through lack of
insulation at some part of the wire, or similar injury, the circuit has
been shortened, owing to this bare wire touching a ground, thus per-
mitting the current to return to its source without passing through
whatever instruments there may be on the circuit. A grounded cir-
cuit, however, is also one in which one side consists of a ground return
instead of having two wires. This is frequently distinguished by
being termed a groundrreturn circuit.

Q. What is a short-circuit?

A. As the term indicates, a completion of the circuit short of the
point or apparatus which the current is intended to reach. The
example just cited is a short circuit as well as a ground, sometimes
termed a grounded short-circuit. In other words, the abrasion of the
insulation of one of the conductors has permitted the current to
escape by a convenient path of return which, being of less resistance
than the one it is intended to take, prevents any current from reaching
the apparatus in the circuit. A ground is practically always a short-
circuit, but the reverse is not always true, that is, a short-circuit need
not necessarily be a ground, as in a double-wire circuit, but the two
conductors may come together at a point where the insulation is
worn, or winding of a coil may break down and cause a short-
circuit.

Q. What are some typical examples of grounded circuits on the
automobile?

A. Both the primary and secondary sides of the ignition circuit
and the starting and lighting circuits of the so-called single-wire sys-
tems in which the chassis is always used as a ground return for all the
circuits employed.

441

Digitized by VjOOQlC

68 ELECTRICAL EQUIPMENT

HYDRAULIC ANALOGUE

Q. What is a hydraulic analogue, and what bearing has it on an
electrical system?

A. It is a comparison of the electrical system with a hydraulic
or water-pressure system and serves to make clear the resemblance
or analogy that exists between the principles upon which both operate.

Q. What type of hydraulic system is similar to an electrical
system consisting of a generator, external circuits, and lamps, motors,
or the like, as a load?

A. A constant-pressure system in which the pumps keep the
water in the pipes under a certain amount of pressure corresponding
to the demand. When the demand increases, the supply does like-
wise and vice versa. (In the case of the pumping system, this is not
automatic, but is controlled by the attendant.)

Q. To what does the pressure of such a pumping system corre-
spond in the electrical system?

A. To the voltage, or electromotive, force.

Q. Can there be voltage, or potential, in an electrical system
without a flow of current?

A. Yes, exactly as in the pumping system in which there is
always a constant pressure on the water in the pipes whether the
water is escaping through any of the outlets or not. In other words,
there may be pressure but no flow. The same thing is true of the
generator. If it be turning at its normal speed and is wound to
produce current at 100 volts, there will be a potential of 100 volts
across its terminals, even though there are no lamps or motors
switched on in the external circuit.

Q. How does the resistance of the pipe lines in the water system
compare with the resistance of the wires in a circuit to the electric
current?

A. It is nearly the same. It varies inversely as the size of
the pipe and directly as its length. The smaller the pipe the greater
the resistance per foot; the longer the pipe the greater the total
resistance. In the same way, the resistance to the electric current
increases with the decrease in the size of the wire and increases with
the length of the wire, the chief difference being that bends or turns
in the wire do not add to the electrical resistance, whereas bends in
the pipe impose greatly added resistance to the flow of water.

442

Digitized by VjOOQIC

ELECTRICAL EQUIPMENT 69

Q. What comparison may be made between the speed at which
the generator and the pumps run?

A. The greater the speed, the greater the pressure in the case of
the pumps, and of the voltage in the case of the generator. Below
a certain speed, usually termed the normal speed, there is a sharp
falling off in the pressure in both. Neither can be operated safely
at an excessive speed.

Q. What is the cause of the increase in voltage with increasing
speed in the case of the generator?

A. Voltage, or electromotive force, is generated by the coils,
or windings, of the armature cutting the magnetic lines of force of
the field of the generator. The greater the number of 'times that
these coils pass through the lines of force per minute, the greater
the voltage will be.

Q. How does fall in pressure correspond to voltage drop?

A. To reach the end of the piping system, the water must over-
come the resistance of the latter to its passage, and the friction
involved robs it of some of its pressure in overcoming this resistance.
Consequently, there is less pressure at the outlet a mile away from
the pumps than there is at the pumps themselves. The same thing is
true of the electric circuit. The current must force its way through
the wires by reason of its voltage or pressure and, in so doing, some of
the voltage is lost in overcoming the resistance of the wires, joints,
switches, and the like. In both cases allowance for this loss is made
by increasing the pressure at the source by an amount equivalent to
the loss in transmission. For example, in electric street-railway work
the motors are wound to operate on current at 500 volts, while the
generators in the powerhouse produce current at 550 to 600 volts,
the difference being known as the voltage drop.

Q. Is this an important matter on the automobile where the
circuits are so short?

A. It is of considerable importance, particularly in connection
with the starting motor circuit. The circuits are very short, but the
initial voltage is likewise very low, so that the percentage available
for voltage drop is correspondingly limited. For example, a drop of
one volt in a 110- to 115-volt lighting circuit is negligible, being less
than 1 per cent, but a drop of one volt in a 6-volt circuit represents
almost 17 per cent and would accordingly be prohibitive. As poor

443

Digitized by

Google

70 ELECTRICAL EQUIPMENT

connections, dirty switch contacts, dirty commutator, and worn
brushes are apt to increase the resistance to a point where the voltage
drop is in excess of this, the importance of properly maintaining these
parts of the system may be appreciated.

Q. How does the flow of water correspond to the flow of
current?

A. In both cases, the amount is proportionate to the resistance
of the outlet and to the pressure back of the current, whether water
or electricity. In other words, the volume of water that will flow
depends upon the size of the outlet (the smaller the outlet the greater
the resistance to the flow) times the pressure back of it. In the same
way the number of amperes that will flow when the circuit is closed
depends upon the voltage of the circuit divided by the resistance
(Ohm's law). For example, the ordinary 16 c.p. carbon-filament
lamp for a 110- volt circuit has a resistance of 220 ohms, which,
divided by 110, gives \ ampere as the current that will flow when the
lamp is switched into the circuit.

Q. Can the piping system properly be compared with an electric
circuit?

A. In practically every way except that of the return required
for the latter. For example, the opening of a series of outlets in the
piping system reduces the pressure in proportion to the number
opened; so in connecting a number of different pieces of apparatus
in series in an electric circuit, the voltage through each will decrease
as another is added. It may also be compared with a parallel or
multiple circuit in that the opening of one outlet does not prevent
drawing water from another. A break in a main corresponds to a
short-circuit or a ground in that no water can then be drawn from any
outlet beyond the break. The comparisons between the piping
system and the circuit are not exact, owing to the lack of any neces-
sity for a return in the case of the water piping, but they serve to
make clearer some of the fundamentals of the electric circuit.

GENERATOR PRINCIPLES

Q. What makes it possible to generate a current of electricity
by mechanical means?

A. The fact that electricity and magnetism are different mani-
festations of the same force and that, given one, the other may be

444

Digitized by CjOOQIC

ELECTRICAL EQUIPMENT 71

produced. Also the fact that they are readily interchangeable,
i.e., one may be readily converted into the other.

Q. On what fundamental principle does the generation of elec-
tricity in this manner depend?

A. That of induction.

Q. How is it utilized?

A. By revolving a coil of wire in the field of a magnet.

Q. What occurs when this is done?

A. An e.m.f . is generated in the coil.

Q. Describe the simplest form of generator.

A. Such a generator consists of a horseshoe magnet between
the poles of which a coil of wire is revolved.

Q. What governs the strength of the e.m.f. or potential, thus
generated?

A. The speed with which the conductor or wire revolves, or is
said to "cut the lines of force" of the magnetic field.

Q. How can this potential be further increased?

A. By winding the coil of wire on an iron core, as the iron
becomes strongly magnetic and greatly increases the inductive effect.

Q. What is this simplest form of generator consisting of horse-
shoe magnets for the field and of a single winding on an iron core
termed, and for what is it employed on the automobile?

A. It is known as a magneto and is generally employed for pro-
ducing the current needed for ignition purposes.

Q. Can such a generator be directly employed for charging a
storage battery or for lighting lamps?

A. No, it cannot be used for charging purposes, since it gen-
erates an alternating current. Moreover, owing to the small number
of poles (two), its single winding, and the high speed at which it is
driven, it produces very little current but a high e.m.f., as this is
desirable for ignition. It cannot be used for lighting purposes for
the same reason, i.e., the simple winding produces an alternating
current with a very perceptible interval between the alternations, or
cycles, so that a lamp would flicker very badly. As its e.m.f., or
voltage, is proportionate to its speed and as there is no method of
controlling it, the lamp would be burned out as soon as the magneto
was speeded up.

Q. What are the essentials of this simple form of generator?

Digitized by VjOOQIC

72 ELECTRICAL EQUIPMENT

A. The field consisting of the horseshoe magnets, and the arma-
ture consisting of a soft iron or steel core, usually in the form of an H,
in the slots of which, the single winding of comparatively coarse wire
is wound.

Q. Why is the field of a magneto usually referred to as a "per-
manent field?"

A. Because it consists of so-called permanent magnets. Nat-
urally, they are not permanent in the real sense of the word, but their
magnetism is constant while it lasts and it decreases only very grad-
ually under the influence of heat and vibration.

Q. Why does heat affect the magnetism of the field of a genera-
tor of this type?

A. Because a piece of hard steel that is strongly magnetic when
cold loses its magnetism altogether when raised to a sufficiently high
temperature. In other words, if heated to a bright red and then
cooled, it is no longer a magnet, and the steel must be remagnetized.
Constant vibration has the same effect, but it is much slower.

Q. Is there any other way of increasing the voltage of such a
generator besides running its armature at a higher speed?

A. Yes, by increasing the number of turns of wire in the wind-
ing, which has the same effect as revolving a single coil at a higher
speed.

Q. How is the current produced by a simple form of generator,
such as the magneto, conducted to an outside circuit?

A. Ordinarily, this would be done by means of slip rings, i.e.,
plain bands of copper mounted on the armature shaft with narrow
copper brushes bearing on these rings, as is the case with large alter-
nating-current generators. But as the ignition system of the auto-
mobile is a grounded circuit, one end of the armature winding of the
magneto is connected directly to the core of the armature, and the
other is led to a small V-shaped ring or to an insulated stud on the end
of the shaft against which either a copper or a carbon brush is held
by a small spring.

Q. What is the cause of the alternating cycle of the magneto,
and at what points in the revolution of the armature does it occur?

A. In revolving in the field of the magnets, the armature passes
successively from the field of influence of a north pole to one of
opposite polarity, so that the direction of the e.m.f. is reversed.

446

Digitized by

Google

ELECTRICAL EQUIPMENT 73

When the armature is in a horizontal position in the field, the e.m.f.
curve is at zero; as it turns, the edges of the armature core pass the
ends of the pole pieces of the field, and the e.m.f. rises sharply to a
maximum as the central line of the core passes the ends of the poles,
when it is said to be cutting the maximum number of lines of force.
It drops off again quickly from this point and again reaches zero,
when the armature is in a vertical position. As its ends come under
the influence of opposite poles, the curve again rises, but is now in the
opposite direction, or of opposite polarity. In other words, it passes
from zero to maximum and back again in every half revolution, or
180 degrees.

Q. How can a generator be made to produce a direct, instead of
an alternating current?

A. The current is always alternating as generated in the arma-
ture, but it may be conducted to the outside circuit as a unidirec-
tional, or so-called direct, current by the addition of a commutator.

Q. Can such a current be produced by the addition of a commu-
tator to the simple single-coil winding already mentioned in connec-
tion with the magneto?

A. Yes, but as the commutator would have but two parts, the
e.m.f., while passing in one direction, would be strongly pulsating.

Q. What is a commutator and how does it convert the alternat-
ing current produced in the armature to a direct current in the outside
circuit?

A. It consists of a number of segments of copper, one for each
coil terminal of the armature, i.e., two for each complete coil of the
winding. These segments are insulated from one another, and
brushes bear at opposite points of the conducting hub thus formed by
the segments. As the terminals of the armature coils are connected
to segments that are opposite one another (in the simplest forms of
winding), and as the brushes, also opposite one another, are set at
points so that they pass from one segment to another when the rate
of cutting is at a minimum in the armature winding, their relation to
the latter is changed each half revolution. In other words, at the
point in the revolution where the polarity of the e.m.f. generated
reverses, the relation of the brushes to the winding is also reversed,
so that the direction of the e.m.f. is accordingly always the same. See
Figs. 20 and 21.

447

Digitized by

Google

74 ELECTRICAL EQUIPMENT

Q. How is the pulsating nature of the direct current thus gener-
ated overcome?

A. By adding coils and commutator bars to the armature so
that new coils come into action before the e.m.f. produced in those
just preceding them under the brushes has an opportunity to drop
much below the peak or maximum. Thus, only the peak of the
wave is utilized, and the e.m.f. of a direct current consists of a series
of these wave peaks overlapping one another.

Q. Are permanent magnets used for the fields of all generators?

A. No, only for those of magnetos. In other types, an electro-
magnetic field is used.

Q. What are the advantages of the permanent field for use in
connection with the magneto?

A. It is always at its maximum strength, so that the magneto
generates a powerful e.m.f., even though turned over very slowly.
Regardless of the speed of the armature, the strength of the field
remains the same, so that no controlling devices are necessary to
prevent the armature from burning out, owing to excessive speed.

Q. What is an electromagnetic field and how is it produced?

A. It is based on the fact that when a current of electricity is
sent through a winding surrounding an iron core, the core becomes
strongly magnetic. It accordingly consists of windings on the fields
of the generator, in addition to those on the armature. Depending
upon the particular type of generator in question, either all or only
part of the current produced in the armature is sent through the
windings of the field. The latter is then said to be self -excited in that
it depends upon no outside source.

Q. Is the self-excited field characteristic of all generators
except the magneto?

A. Yes, of all direct-current generators. Large alternating-
current generators are said to be separately excited, a smaller direct-
current generator being employed solely for the purpose of rendering
the fields of the larger machine magnetic.

Q. What is a series-wound generator, and why is this type not
used on the automobile?

A. It is one in which the entire current generated in the arma-
ture is passed through the field windings. It does not generate until
a high speed is reached. Its voltage varies sharply as its speed, and

Digitized by VjOOQlC

ELECTRICAL EQUIPMENT 75

it may have its polarity reversed by the battery if its speed drops
below a certain point, consequently, it is not fitted for charging
storage batteries. (In fact, the series-wound generator is practically
obsolete, except for some special uses.)

Q. What are shunt- and compound-wound generators?

A. In the former, the windings of the armature and of the fields
are in multiple, or shunt, so that only a certain amount of current,
depending upon the difference in the resistance of the outside circuit
and that of the fields, passes through the windings of the latter. As
the load and consequently the resistance of the outside circuit
increases, more current passes through the shunt, and the fields
become more strongly magnetic, thus increasing the output so that
the generator is, to a certain extent, self-regulating.

In the compound type, there is, in addition to the main shunt
winding on the fields, an auxiliary winding of heavier wire (lower
resistance) which is connected in series with the armature. As in a
series-wound generator, the amount of current exciting the fields is
directly proportional to the speed, more current in proportion passes
through the compound winding than through the shunt winding as
the load is increased, and the generator is self-regulating to a much
greater degree. The compound-wound type of generator is in prac-
tically universal use on the automobile as well as for general power
purposes. See Figs. 31 and 32.

Q. What is meant by the term "self-regulating" as used in the
preceding paragraphs?

A. The generator automatically produces more current in
response to the demand occasioned by an increase in the load, without
any change in its driving speed.

Q. How is this accomplished?

A. The amount of current produced by the generator depends
upon the strength of its magnetic field in which the armature revolves.
The magnetism of this field represents the so-called lines of force.
The greater the number of lines, or the more powerful they are per
unit of pole-piece surface, the greater the volume of current that will
be generated. In practical usage, this is referred to as the magnetic
flux, or flow, through the armature. By increasing or decreasing
the amount of this magnetic flux through the armature, the current
output can be controlled within close limits.

449

Digitized by

Google

76 ELECTRICAL EQUIPMENT

Q. What is meant by the "load" on a generator?

A. The lamps, motors, storage battery, or similar apparatus to
which it is supplying current.

Q. As the speed of the generator itself does not increase, how
does it provide for an increase in the load?

A. By absorbing more power from its driving unit. For
example, if a generator be operating with only ten 100-watt lamps in
the circuit, it is requiring approximately one and one-half horsepower
to drive it. Now, if another group of ten lamps of the same size be
switched on, the amount of power demanded by the generator of its
engine will be doubled. This may be very readily demonstrated in a
rough way by fitting a handcrank to any small automobile generator
and turning the machine over with one lamp in the outside circuit.
It will be found very easy to spin the generator very rapidly by hand,
as practically no resistance is felt. Now connect in the circuit a
discharged storage battery, and the additional power required to
turn the machine will at once be very perceptible.

Q. What are the brushes and what purpose do they serve?

A. They are strips of copper or carbon (the latter is now almost
universally used), which serve to conduct the current generated in
the armature to the outside circuit and to the field windings by
bearing on the revolving commutator. Except where an additional
brush is employed for regulating purposes, there is usually one brush
for each pole of the field, i.e., a bipolar generator is fitted with two
brushes, a four-pole with four brushes. The brushes are held against
the commutator by springs. Soft copper embedded in carbon is also
employed, especially for low-voltage generators, such as the lighting
generator on the automobile.

ELECTRIC MOTORS

Q. Is there any difference in principle between the electric
generator and the electric motor?

A. Fundamentally, they are the same, as is evidenced by the
fact that either is reversible, that is, an electric generator, when
supplied with current from an outside source (of the proper voltage,
of course), will operate as a motor, and a motor, when driven by an
outside source of power, will generate an electric current. They are
naturally not interchangeable in practice, owing to differences in

450

Digitized by

Google

ELECTRICAL EQUIPMENT 77

design and winding. The generator is wound to produce the maxi-
mum amount of current at a certain voltage with a given horsepower,
while the motor is designed to produce the maximum amount of power
with the minimum current.

Q. What is the operative principle of the electric motor?

A. That of magnetic attraction and repulsion.

Q. How is it applied?

A. As in the generator, both the fields and the armature of the
motor consist of electromagnets. The brushes and the commutator
serve the same purpose of reversing the direction of the current
through the armature coils every time a different pair of commutator
segments passes under the former. As has already been explained,
reversing the direction of current flow through the winding of an
electromagnet reverses the polarity of the magnet itself. To sim-
plify the illustration, take a bipolar motor with a two-pole armature
having but a single winding. When the current is switched on, the
armature is at a 45-degree angle, so that its poles are just under the
poles of the field. As the commutator causes the current to flow
through the armature winding in a reverse direction to that of the fields,
unlike poles will be created. They will attract each other, and the
armature will revolve a small part of a revolution, until it is directly
in the strongest part of the field of the influence of the field magnets.
Just as this point is reached, however, the brushes pass on to new
segments of the commutator, and the direction of the current in the
armature coils is instantly reversed. The polarity of the armature
core is also reversed, so that there are now like poles opposed to one
another, and they repel, causing the armature to complete another
part of its revolution, when the former conditions are again estab-
lished and the armature is again attracted. In a bipolar motor with
a simple two-pole armature, there would be two phases of attraction
and repulsion per revolution. In larger motors this is multiplied by
the number of poles in the field and the number of coils on the
armature.

Q. As an electric motor in running fulfills all the conditions
necessary for the generation of an e.m.f., what becomes of this
voltage?

A. It constitutes what is termed a counter e.m.f. and serves the
useful purpose of increasing the resistance of the motor when in

451

Digitized by

Google

78 ELECTRICAL EQUIPMENT

operation, thus reducing the amount of current necessary to drive it.
For example, when the motor is standing idle, the resistance of its
windings is low. It is for this reason that large direct-current motors
(one h.p. or over) cannot be started without the aid of an outside
resistance to cut down the starting current, otherwise the armature
would be burned out. As the armature speeds up, the counter e.m.f .
generated opposes that of the driving current and accordingly
increases the resistance. The heating of the windings in operation
further serves to increase the resistance, as the resistance of most
metals increases with a rise in their temperature.

Q. How many types of motors are there, and what type is most
generally used for automobile starting?

A. As they correspond exactly to generators, there are the
same number of types, i.e., series, shunt, and compound wound.
The series type is almost universally employed on the automobile and
is also very largely used on trolley cars.

Q. If the series-wound generator is of so little practical applica-
tion, how is it that the series-wound motor is found so advantageous?

A. The same characteristics that are a disadvantage in the
generator are correspondingly valuable in a motor, which explains
why generators and motors are not interchangeable in practice, as
already mentioned. A series-wound machine is essentially a variable-
speed machine, and this is not desirable in a generator, while it is in a
motor. The series type of motor has a very heavy starting torque,
or pull, which increases as the speed of the motor decreases. This is
exactly what is wanted to overcome the inertia of the gasoline engine.
Its current consumption falls off very quickly as its speed increases,
and it has a very liberal overload capacity, being capable of carrying
loads up to five times the normal, for short periods.

Q. As the speed of the series motor decreases in proportion to
the load, what happens when the load is suddenly relieved as in the
starting of the gasoline motor?

A. The electric motor tends to race, or run away.

Q. How is this prevented on the automobile?

A. The method employed differs in different systems, but, as a
rule, the starting of the gasoline engine automatically opens the
starting motor circuit, or means are provided for greatly reducing the
amount of current it receives the moment the load is removed.

462

Digitized by

Google

ELECTRICAL EQUIPMENT 70

Q. Are either shunt- or compound-wound motors used on
automobiles?

A. They are employed on electric vehicles, but not often in
connection with the starting systems used on gasoline cars.

Q. What is a motor-generator, and what is it employed for?

A. As its name indicates, it consists of two units, a motor and a
generator, the former having an alternating current, and the latter a
direct current. It is employed for converting an alternating current
into a direct current, so that it may be utilized for charging storage
batteries. The alternating-current supply is used simply for running
a motor of that type to which is directly coupled a direct-current
generator. There is no electrical connection between the two
machines.

Q. Are motor-generators ever used on automobiles?

A. No, but the combination of a direct-current generator and a
starting motor in one machine, as in the single-unit systems, is fre-
quently so-called through error. This single unit is variously termed
a dynamotor and a genemotor to distinguish it from a motor-generator.

Q. How are the two radically different purposes for which the
generator and the motor must be designed combined in one machine?

A. By putting independent windings on the fields and the arma-
ture, and, in some instances, by employing two commutators at
different ends of the armature shaft.

BATTERIES

Q. What other method is there of producing an electric current
besides that of driving a dynamo?

A. The use of batteries known as primary and secondary cells.
Q. What is the difference between these two types?

A. In the primary cell, the current is generated by means of
the chemical reaction taking place between electrodes of different
materials in an acid or alkaline solution, one electrode being dissolved
in the solution as the chemical action continues.

The secondary cell is the storage battery. This does not generate
a current of electricity as in the case of the primary cell, nor does it
actually store electricity as its name would indicate. The passing of a
current through its elements brings about a chemical conversion of the
latter, which is reversed when the current flows out of the cell.

453

Digitized by

Google

Digitized by

Google

REVIEW QUESTIONS

4$5

Digitized by

Google

REVIEW QUESTIONS

ON THE SUBJECT OF

GASOLINE AUTOMOBILES

PART IV

1. How is gradual engagement secured in a cone clutch?

2. What are the disadvantages of the inverted cone clutch?

3. Sketch a typical contracting band-clutch.

4. What type of clutch is used in the 8-cylinder V-type Cadillac?

5. What is the coefficient of friction between cork and leather
used dry in a clutch?

6. What are the parts used in a magnetic clutch?

7. When a metal-to-metal oiled clutch slips, what is the cause
of the trouble?

8. What are* the causes of clutch spinning?

9. What is the difference between the progressive and the
selective transmission; why has the former been discarded?

10. What transmission is used on the Winton?

11. What is an interlocking device?

12. How are transmission adjustments made?

13. Describe the Manly drive.

14. Sketch and explain the Owen magnetic transmission.

15. What troubles may be expected in the planetary type of
transmission?

16. Why is the worm gear generally used in steering devices?

17. What is the maximum efficiency obtainable with a worm
gear?

456

Digitized by

Google

REVIEW QUESTIONS

ON THE SUBJECT OF

GASOLINE AUTOMOBILES

PART V

1. Explain the action of the Winton steering gear,

2. Describe the action of a correct steering arrangement in
turning a corner.

3. What are the double requirements of a correct steering
gear?

4. Name the different forms of steering gears now in use and
describe one form.

5. Why is the worm utilized in nearly all steering gears?

6. Give the special advantages of the Hindley worm over other
forms.

7. How does the drag link used in the Ford steering gear differ
from conventional designs?

8. Give the test for backlash in an irreversible type of steering
gear.

9. Why is it necessary to use at least one universal joint in
a steering rod?

10. Discuss steering in 4-wheel drive types.

11. What is the difference between the Elliott and the Reversed
Elliott front axles?

12. Describe the Marmon self-lubricating axle.

13. Why are sub-frames used?

14. Discuss wood frames and name American car that has its
frame made of wood.

15. What is the peculiarity of the Marmon frame?

16. Explain the Hotchkiss drive.

467

Digitized by

Google

REVIEW QUESTIONS

ON THE SUBJECT OF

GASOLINE AUTOMOBILES

PART VI

1. Discuss the advantages of flexible joints when used in place
of universal joints.

2. Give the advantages and disadvantages of the shaft drive

3. Why are torque rods necessary?

4. Into what classes may rear axles be divided?

5. What percentage of 1917 cars use the three-quarter floating
axle?

6. Describe the rear-axle construction of the Case car.

7. Explain the action of a gearless differential.

8. How may a sagging axle be adjusted?

9. How many sets of brakes should be used on a chain-driven
car?

10. Describe the action of the brake used on the Knox tractor.

11. Why have substitutes been sought for the ordinary dif-
ferential?

12. What are the advantages of silent chains?

13. What system of final drive is used in the Metz?

14. How may chattering be eliminated in internal-expanding
brakes?

15. What is meant by "checking up" axles?

16. What are the advantages of double-brake drums?

458

Digitized by

Google

REVIEW QUESTIONS

ON THE SUBJECT OF

ELECTRICAL EQUIPMENT FOR
GASOLINE CARS

PART I

1. What is an electromagnet; how is it used?

2. Explain what is meant by (a) a short-circuit; (b) a ground

3. A certain 12-volt starting motor required an average current
of 80 amperes to turn the automobile engine over fast enough
to start it. How many horsepower is developed by the starting
motor?

4. Describe the process of generating an e.m.f. wave by a
dynamo.

5. If pure water is an insulator, why is it necessary to keep the
spark plugs and other parts of the secondary circuit dry?

6. What is a dynamotor?

7. Give the rule for determining the direction of current flow
in a solenoid winding.

8. What is meant by "voltage drop"?

9. Give the diagrams of series, shunt, and compound generator
windings.

10. Explain how rotation is produced in an electric motor.

11. Give diagram of a lighting circuit for an automobile, showing
lights in multiple.

12. What are the differences between shunt-, series-, and
compound-wound generators?

459

Digitized by

Google

Digitized by

Google

INDEX

Digitized by

Google

Digitized by

Google

INDEX

The page numbers of this volume trill be found at the bottom of the pages;
the numbers at the top refer only to the section.

Air cushion

Annular bearings, adjusting

Armature windings

Automatic gear-cutting machine

Axle bearings

ball

classification

roller
Axle pivots, inclining
Axles, front

Ball bearings 162
Batteries 427, 453

Bead of tire 336

Bearing balls, saving 77

Bearings, clutch 29

Becker gear-cutting machine 84
Bevel gears 88,114,261
Bevel pinion and sector steering

gear 122

Bevel type friction transmission 62

Bilgram gear-planing machine 87

Blowouts 355

inside and outside method 357

inside repair methods 356

Brake adjustments 275

Brake drums, truing 283

Brake lining, stretching 282

Brake lubrication 275

Brake operation, methods of 272

Brake troubles and repairs 279

dragging brakes 279

dummy brake drum useful 280

eliminating noises 282

to stop brake chattering 280

stretching brake lining 282

Not*. — For page numbers eee foot of page*.

Page Page

Brake troubles and repairs (con-

214 tinued)

$1 truing brake drums 283

412 Brakes 266

g3 brake adjustments 275

131 brake lubrication 275

152 classification 267

161 double-brake drum for safety 272

102 electric brakes 275

100 external-contracting brakes 267

151 function of brake 266

hydraulic brakes 276

internal-expanding brakes 268

methods of brake operation 272

recent developments 275

summary of instructions 361

troubles and repairs 279

vacuum brakes 277

Browne and Sharpe gear-cutting

machine 83

Brushes 420

Cable drives 62

Camber complicates axle ends 156

Cantilever spring 194

Capacity of condensers 403

Casing repairs 354

Cast axles 157

Chain four-wheel drive 145

Changing tires 312
speed changes due to changed

tires 314

Chassis group 168

characteristics of parts 168

frames 169

shock absorbers 209

springs 190

463

Digitized by

Google

INDEX

Page

Chassis group (continued)

summary of instructions 223

Circuits 377, 385, 407, 440

multiple or shunt 387

series 386

series-multiple 387

Clincher rims 316

Clutch forms in semi-, three-
quarter, and full floating

rear axles 246

Clutch group 1 1

details of clutch operation 26

summary of instructions 94

types of clutches 11

Clutch operation, details of 26

clutch accessibility 30

clutch adjustment 30

clutch bearings 29

clutch lubrication 28

clutch pedals 27

gradual clutch release 27

methods 26

Clutch troubles and remedies 30

adjusting clutch pedals 38

clutch spinning 35
clutch troubles outside clutch 39

cork inserts 35

fierce clutch 34

Ford clutch troubles 34

handling clutch springs 33

replacing clutch leathers 31

slipping clutch 30

summary ' 39

Clutches, types of 11

classification 1 1

cone clutch ♦ 12

contract ing-band clutch 14
expand ing-band, or ring, clutch 15

disc clutch 16

magnetic clutch 24

requirements applying to all

clutches 1 1

Coil-spring shock absorber 211

combinations 212

double-coil spring types 213

springs alone 211

Commercial-car wheels 298

Note. — For page numbers tee foot of pages.

Page
Commercial-car wheels (contin-
ued)
cast-steel wheels 301

miscellaneous wheel types 301

modern status of spring wheel 304
requisites 298

wood wheels 299

Commercial-vehicle frame con-
struction 183
Commutators 409
Compound- wound generator 418
Condensers, capacity of 403
Conductors 382, 390, 437
Cone clutch 12
Contracting-band clutch 14, 56
Cord tires 315
Counter e.m.f. 424
Couple-Gear wheel 150
Cross-connecting rods 138
Current 377, 392, 405
chemical effect 393
heating effect 392

Demountable rim tire types 309

Demountable rims 322, 333

comparison of continuous hold-
ing ring type with local
wedge type 329

local wedge type 322

process of changing Baker local

wedge type 324

rim with straight split 328

for wire wheels 333

Differentials on rear axles, effect of 251
improved forms 253

possible elimination 255

Disc clutch 16

floating discs 22

greater power transmitted by

surfaces not plane 22

metal-to-metal dry-disc type 19

multiple-disc clutches 18

popularity 16

simple types 17

two forms of same make 16

use of facings 20

464

Digitized by

Google

INDEX

Disc individual clutch 56

Double-brake drum for safet}' 272

Double-chain drive 238

Drag link 134

Driving reaction 241

Drop forgings for front axles 158
Dropped rear axle of full floating

type 245

Dummy brake drum useful 280

Dunlop tire 307

demountable rim types 309

non-skid treads 309

Dynamo 408

Dynamotors 425

E
Electric brakes 275
Electric car springs 201
Electric circuit 377, 440
chemical effect of current 393
circuits 385
conductors 382
current 377
electrical pressure 378
heating effect of current 392
non-conductors 384
Ohm's law 379
power unit 380
resistance 379
short-circuits and grounds 389
size of conductors 390
voltage drop 383
Electric drive 64, 65, 149
Couple-Gear type 150
Electric generating clutch 24
Electric motor principles 421, 450
batteries 427
counter e.m.f. 424
dynamotors 425
theory of operation 421
types of motors 424
Electric transmissions 64, 65
Electrical devices, inherent weak-
ness of 375
Electrical equipment for gasoline

cars 375-453
elementary electrical principles 376

introduction 375

Note — For page numbers see foot of pages.

Page
Electrical pressure 378, 404

Electrical principles, elementary

376, 428
electric circuit 377

induction principles in genera-
tors and motors 401
knowledge of principles neces-
sary 376
magnetism 394
Electrically operated gears 53
Electricity, importance of on auto-
mobiles 375
Electromagnets 396
Elliott front axle 152
reversed Elliott 152
Epicyclic, or planetary, gears 59
Expanding-band clutch 15
External-contracting brakes 267

Fellows gear shaper 84

Fergus frame 176

Field magnets 414

forms of field magnets 420

permanent field used in magneto 414

self-excited fields 417

Final-drive group 231

brakes 266

rear axles 231

summary of instructions 361

tires 307

wheels 284

Flat-plate recoil springs 214

Flexible joints 234

Floating disc clutch 22

Folding steering wheels 133

Ford axles, checking up 265

Ford clutch troubles 34

Ford planetary gears 60

Ford spring 200

Ford steering gear 125

Forgings for front axles 158

Four-wheel driving, steering, and

braking 142
advantages of four-wheel drive 149

chain four-wheel drive 145

JefferyQuad 145

465

Digitized by

Google

INDEX

Page

Frame bracing methods 189

Frame troubles and repairs 185

fracture 186

frame bracing methods 189

riveting frames 187

sagging 185

Frames 168, 169

classes of frames 170

effect on springs 173

general characteristics 169

pressed-steel frames 172

rigid frame 173

sub-frames 173

tendency in design 171

types 175

summary of instructions 223

troubles and repairs 185

Friction disc 61

bevel type 62

spur type 61

Frictional-plate shock absorber 210

Front axle troubles and repairs 163

alignment of front wheels

troublesome 163

spindle troubles and repairs 167

straightening axle 165

wobbling wheels 167

Front axles 151

axle bearings 161

materials 157

troubles and repairs 163

types 151

Front-wheel drive 140

control 142

difficulties of transmission 140

friction-disc transmission 141

Full-elliptic spring 192

Full floating axle 243, 248

Gasoline automobiles
chassis group
clutch group
final-drive group
steering group
transmission group

Note. — For page number* *e* foot of pace*.

Gasoline railway cars, transmis-
sion needs of 55
Gather complicates axles 157
Gear-cutting machines, types of 81
automatic 83
Becker 84
Bilgram 87
Browne and Sharpe 83
Fellows 84
Gleason 85
Whiton 82
Gear operation, noise in 69
Gear pitch and faces 93
Gear pullers 71
Gear shifting
pneumatic system 65
poor 72
Gear troubles 93
Gears 81
types of gear-cutting machines 81
types of gears in automobile 88
Gears in automobiles 88
bevel 88
gear pitch and faces 93
gear troubles 93
helical and herringbone 89
spiral 90
spiral bevels 91
worm gears 92
Generator principles 408, 444
armature windings 412
brushes 420
classification 408
commutators 409
elementary dynamo 408
field magnets 414
Gleason gear planer 85
Gravity-return layout of tire re-
pair equipment 347
Grounds 389

11-373

168

Haywood vulcanizer

341

Helical gears

231

Herringbone gears

105

Hindley worm gear

124

Hotchkiss drive

196

466

Digitized by

Google

INDEX

Hydraulic brakes
Hydraulio clutches
Hydraulic gear

Janney- Williams

Manly
Hydraulic suspensions

Page
276
24
63
63
63
217

Individual clutch 55

general types used 55

transmission adjustments 59

transmission bearings 69

transmission lubrication 58

transmission operation 58

Induction 401

Induction principles in generators

and motors 401, 435

capacity of condensers 403

circuits 407

comparison of generator current

to water flow

403

current and volume

405

electric motor principles

421

friction and resistance

405

generator principles

408

induction

401

power comparison

406

pressure and voltage

404

self-induction

402

Inner tube repairs

351

inserting new section

353

patches

351

Inner tubes, improvement in

315

Interlocking devices for gears

Internal dogs, individual clutch

using

Internal-expanding brakes

268

Internal-external gear individual

[

clutch

Internal-gear drive for trucks

J
Jacking-up troubles

247

256

substitute for jack

257

Janney-Williams hydraulic gear

Jeffery Quad

145

K
Knox tractor spring

Lemoine front axle
inverted Lemoine
Lines of magnetic force
Locomobile spring
Lubrication

Page
198

154
155

399
201

28, 58, 80, 140, 206, 256, 275

Magnetic attraction and repulsion,

laws of

395

Magnetic clutch •

Magnetic field

397

Magnetic force, lines of

399

Magnetic substances

396

Magnetism 394

,432

electromagnets

396

laws of magnetic attraction and

repulsion

395

lines of magnetic force

399

magnetic field

397

magnetic substances

396

natural and artificial magnets

394

poles of magnet

395

solenoids

399

Magneto, permanent field used in

414

Manly hydraulic gear

Marmon self -lubricating axle

155

Marmon spring

197

Metal-to-metal dry-disc clutch

Motor

summary

450

theory of operation

421

types of

424

Multiple circuit

387

Multiple-disc clutches 18, 39

Noisy bevel gears 261

Non-conductors 384

Non-return layout of tire repair

equipment 347

Non-skid treads 309

Nat*. — For page numbers ate foot of pages.

467

Digitized by

Google

Ohm's law

379, 431

Outer shoe repairs

354

blowouts

355

classifying troubles

354

retreading

358

rim-cut repair

357

sand blisters

355

summary

360

use of reliner

360

Oversize tires, use of
P
Packard bevel adjustment

311

261

Parker pressed-steel wheels

297

Parker rim-locking device

334

Patches on inner tubes

351

Pedals, clutch

27,38

Perlman rim patents

330

Plain rim

316

Planetary gears

Ford type

method of action

Platform spring

193

Pleasure-car steering wheels

131

Pleasure-car wheels

286

Parker pressed-steel wheels

297

sheet-steel wheels

294

wire wheels

290

wood wheels

286

Pneumatic drive

Pneumatic system of gear shifting 55

Pneumatic tires

307

changing tires

312

classification

307

proper tire inflation pressures 310

recent tire improvements

314

Poles of magnet

395

Power unit

380

Pressure

378, 404

Progressive gears

Punctures in tires, repairing

351

Q.D. rim

316

Quick-detachable rim

316

clincher forms

321

INDEX

Page p ag e

Quick-detachable rim (continued)
No. 2 319

type for straight sides 322

Rear axle carrying load and drive 244

251
256
256
265
256
264
261
259
258
257
231
361
231
256
243

Rear-axle housings
Rear-axle lubrication
Rear-axle troubles and repairs

checking up Ford axles

jacking-up troubles

locating trouble

noisy bevel gears

rear axle

universal-joint housings

workstand equipment
Rear axles

summary of instructions

transmission

troubles and repairs

types of rear axles
Rear construction, disassembling

and assembling 260

Rear-end of frame, changes in 183

Rear-wheel bearings 255

Reliner, use of 360

Resistance 379, 382, 405

of materials 382

Retreading 358

building up tread 359

repairing carcass 358

Retreading vulcanizers 346

Reversed Elliott front axle 152

Rigid frame 173

Rim-cut repair 357

complete rim cut 358

partial cut 357

Ring clutch 15

Roller bearings 162

Sand blisters 355

Selective types of sliding gears 41, 42
four-speed type with direct drive

on high 43

four-speed type with direct drive

on third 45

Note. — For page numbers ate foot of page*.

468

Digitized by

Google

INDEX

Page

Self-excited fields

417

Self-induction

402

Semi-elliptic spring

191

Semi-elliptic truck spring

198

Semi-floating rear axle

243, 246

Semi-reversible gear

127

Series circuit

380

Series generator

417

Series-multiple circuit

387

Seven-eighths floating rear axle 243

Shackles for springs 204

Shaft drive 235

Shaler vulcanizer * 341

Shock absorbers 169, 209

air cushion 214

coil springs 211

flat-plate recoil springs 214

frictional-plate 210

function 209

general classes of absorbers 209

hydraulic suspensions 217

overload springs 218

summary of instructions 226

Short-circuits 389

Shunt circuit 387

Shunt-wound generator 418

Side-wall vulcanizer 345

Silent-chain drive 239

Single-disc individual clutch 56

Sliding gears 41

electrically operated gears 53

general method of operation 41

interlocking devices . 51

modern selective types 42

pneumatic shifting system 55

progressive type 41

railway car needs 55

selective type 41

transmission location 45

Slip joints 233

Small tool tire repair equipment 349

Solenoids 399

effect of iron core on strength of

solenoid 401

Spark lever 134

Spindle troubles and repairs 167

Spiral bevel gear 91

Note. — For page numbers see foot of panes.

Page
Spiral gears 90
Spring clips, repair for broken 262
Spring troubles and remedies 206
broken springs 208
general hints on spring repairs 208
lubrication 206
tempering or resetting springs 208
Spring wheels 301
Springs 33, 169, 190
adjusting spring hangers 204
basis of classification 190
cantilever 194
cluteh 33
full-elliptic 192
Hotchkiss drive 196
platform 193
semi-elliptic 191
shackles and spring horns 204
spring construction and mate-
rials 206
spring lubrication 205
summary of instructions 226
three-quarter elliptic 192
troubles and remedies 206
unconventional types 197
varying methods of attaching

springs 202
Spur gears 88, 114

Spur type friction transmission 61
Steering-gear assembly troubles

and repairs 129
lost motion and backlash 129
lost motion in wheel 129
Steering gears 105
action of wheels in turning 107
Ford steering gear 125
general characteristics of steer-
ing gears 110
general requirements 105
inclining axle pivots l>j
removing i v.h
semi-reversible \li
»pur and level 114
steering levers in front of axle 108
troubles and remedies 129
worm-gear 115
Steering group 105

469

Digitized by

Google

INDEX

Steering group (continued)
front axles
gears

rod, or drag link
special types of drive
summary of instructions
wheels

Steering knuckles

Steering levers in front of axle

Page

151
105
134
140
218
130
139
108

Steering rod 134

cross-connecting, or tie, rods 138
function and shape of steering

knuckles ' 139

lubrication of steering-gear as-
sembly 140
operation 134
types of construction 136
Steering wheels 130
different forms of hand wheels 130
different wheels for commercial

use 131

throttle and spark levers 134

Sub-frames 173

Tables

American wire gage (B.& S.) 391

carrying capacity of wires 394

Three-quarter elliptic spring 192

Three-quarter floating axle

243, 246, 250

Throttle lever 134

Tie rods 138

Tire construction 335

bead 336

composition and manufacture 335

tire valves 337

Tire improvements, recent 314

cord tires 315

inner tubes 315

tire valves 314

Tire inflation pressures, proper 310
use of standard pressure and

oversize tires 311

Tire repair, materials used 351

Tire repair equipment 339

inside casing forms 345

Note. — For page numbers see foot of pages.

Page
Tire repair equipment (continued)

layouts of equipment 347

materials 351

retreading vulcanizers 346
separate casing molds for patch

work 343

side-wall vulcanizer 345

small tool equipment 349

types of vulcanising outfits 341
vulcanization of tires for repair

man 339

vulcanizing kettles 344

Tire repairs 339

inner tube repairs 351

outer-shoe, or casing, repairs 354

repair equipment 339

Tire rims 316

clincher 316

demountable 322

kinds 316

Perlman rim patents 330

other removable forms 333

plain 316

quick-detachable 316

standard sizes 331

Tire valves 314, 337

action 338

improvement in 314

leaky valves 338

Tires 307

kinds '" 307

pneumatic tires 307

rims 316

summary of instructions 361

tire construction 335

tire repairs 339

Tires and rims, standard sizes 331

Torque bar 239

Transformer principle 401

transmission 231

driving reaction 241

other flexible joints 234

slip joints 233

torque bar and its function 239

types 234

units in final drive 231

universal joints 232

470

Digitized by

Google

INDEX

Page

Transmission adjustments 59

Transmission bearings 59

Transmission group 40

classification 40

freak drives 62

friction disc 61

gears 81

individual clutch 55

miscellaneous types 62

planetary gears 59

sliding gears 41

summary of instructions 99

troubles and repairs 69

Transmission location 45

amidships alone or with clutch 47

amidships joined with driving

shaft 47

rear unit with rear axle 49

unit with engine 45

Transmission lubrication 58, 80

Transmission operation 58

Transmission troubles and repairs 69

care in diagnosis 72

cleaning transmission gears 74

gear pullers 71

handy spring tool 77

heating 70

lifting out transmissions 75

pressing gears on shafts 71

noise in gear operation 69

poor gear shifting 72

possible troubles 78

saving balls 77

summary 80

transmission stands 75

working in bearings 76

Truck types of steering wheels 131

Truss rods 259

Tubular axles 159

drop-forged ends 159

Underpans, steel p 181

Underslinging springs 203

Note. — For page numbers Bee foot of pages.

Universal-joint housings
Universal joints

Page
258
232

Vacuum brakes 277

Voltage 404

Voltage drop 383

Vulcanization of tires 339

Vulcanizere, retreading 346

Vulcanizing kettles 344

Vulcanizing outfits 341

Haywood 341

inside casing forms 345

retreading vulcanizers * 346

separate casing molds for patch

work 343

Shaler 341

side-wall vulcanizer 345

vulcanizing kettles 344

Wheel pullers 305

Wheel sizes 284

advantages of large wheels 284

Wheel troubles and repairs 305

Wheels 107, 284

action in turning 107

commercial-car wheels 298

pleasure-car wheels 286

summary of instructions 361

troubles and repairs 305

wheel sizes 284

Whiton gear-cutting machine 82

Win ton spring 199

Workstand equipment 257

Worm gears 92, 115

Worm type steering gear 115

Hindley worm gear 124

worm and full gear 116

worm and nut 118

worm and partial gear 115

worm and worm 121

471

Digitized by

Google

Digitized by

Google

Digitized by

Google

Digitized by

Google

Digitized by

Google

Digitized by

Google

Digitized by

Google

Digitized by

Google

Internet Archive Audio

Featured

Top

Images

Featured

Top

Software

Featured

Top

Books

Featured

Top

Video

Featured

Top

Mobile Apps

Browser Extensions

Archive-It Subscription

Save Page Now

Full text of "Automobile Engineering"

See other formats