US Patent 2599078: Automatically locking zipper

June 3, 1952

Filed AuE. 8, 1947

G. SUNDBACK
AUTOMATICALnY LOCKING ZIPPER

2,599,078

$ Sheets-Sheet i

June 3, 1952

Filed Aug. 8, 1947

G. SUNDBACK
AUTOMATICALLZ. LOCKING ZIFPER

2,599,078

5 Sheets-Sheet 2

j..I-.a  OEideon ,.undadc

June 3, 1952

Filed Aug. 8, 1947

G. SUNDBACK
AUTOMATICALLY LOCKING ZIPPER

2,599,078

 Shee%s-Shee% S

92 94

Patented June 3, 1952 2,599,078

UNITED STATES PATENT OFFICE

2,599,078
AUTOMATICALLY LOCKING ZIPPER
Gideon Sundback, MeadviHe, Pa., assignor to
Talon, Inc., Meadville, Fa., a corporation of
Pennsylvania
Application August 8, 1947, Serial No. 767,i26
8 Claires. (CI. 24--205.14)

1
This invention relates to automatic lock zippers.
Such zippers have a pair of stringers or rows of
interlocking elements, collectively called chain,
and a slider embracing the chain for opening and
closing the zipper by movement in opposite
rections along the chain. The slider is automati-
cally locked to the chain against undesired open-
ing movement but is freely movable to close the
zipper.. This is accomplished by an automatic
lock or pawl, normally pressed against the chain
by a spring and shaped to prevent movement of
the slider in the opening direction, but permit-
ring dragging or ratcheting of the pawl over the
chain whenever the slider moves in the closing
direction. The slider has a small handle or pull
tab by which it is moved in either direction, and
the pull tab automatically lifts the pawl out of
engagement with the chain whenever the pull is
operated to open the zipper.
While such zippers serve their intended pur-
poses within certain inherent limitations, they
bave several disadvantages. Since they depend
upon the force of the spring to effect locking, a
strong spring is required to lock them securely,
and this constantly urges the pawl so firmly
against the chain that it ratchets roughly over
the interlocking elements whenever the zipper is
closed. This is objectionably noisy, it makes the
slider rough to operate, and the pawl wears on
the interlocking elements, rapidly destroying its
locking point and destroying the locking action
of the slider. When such a lock is used on colored
zippers, the locking point rapidiy destroys the
enamel or chemical finish on the chain. On the
other hand, if it is sought to eliminate these dis-
advantaes by using a light spring, uncertainty
and insecurity of locking result, and with some
types of interlocking elements, positive locking is
impossible.
Another objection to previously known lock
zippers is that whenever the pawl is holding the
zipper locked against a strong opening force (pro-
duced by trying to pull the stringers apart) it is
difficult or impossible to unlock the slider and
open the zipper by pulling the tab. This may
occur, for example, in corsets. This difliculty is
due to two conditions, first the required unlock-
ing movement of the pawl is thœe direct opposite
oî its locking movement in the saine path, and
second the force by which an interlocking element
bears on the pawl is substantially perpendicular
to this path. Therefore when the force tending
 open the zipper is grœeat, great friction is cre-
ated which must be overcome in the unlocking
movément. In addition, if the parts are rough,

2
or if burrs are present, it may be quite impossible
to unlock the zipper by any force which the user
can apply to the pull tab with the fingers.
It is among the objects of the present invention
5 to provide an improved form of lock slider in
which certainty and security of locking are
fected and in which ratcheting of the lock in
closing the zipper is eliminated or greatly ,re-
duced; to provide an improved lock slider which
10 is instantly and positively locked upon the slight-
est tendency toward undesired opening; to pro-
vide an improved lock which can be unlocked
readily and by slight force even when securely
locked against great opening force, and more
15 specificallY fo provide a locking member which is
moved from locked position to unlocked position
by a different movement and along a different
path than from unlocked position to locked posi-
tion; and te provide an improved lock which
20 normally held in a neutral position from which
it may be moved automatically either to fully
unlocked position when the zipper is intentionally
opened, or may be moved to fully locked position
by the interlocking elements themselves whenever
25 the zipper tends ix) open itself.
I bave round that in some instances, while
is desirable to accomplish these objects, it may not
be desirable to have an absolutely positive lock,
for in some uses of the zipper very great and
30 normal unintentional opening force on the slider
may destroy the zipper or the article ix) which
is applied. In these instances it is desirable to
bave a reliable lock having the characteristics of
a positive lock against normal opening force, but
85 having a safety release which unlocks the zipper
when the opening force becomes great enough to
cause damage. Accordingly it is another object
of my invention ix) provide an improved slider
design bY which I can control the point at which
4O the slider will be released without damage, even
to the extent of absolutely preventing release
where this is desirable.
It is a further object of my invention te provide
a lock slider having the characteristics enumer-
45 ated and which can readily and economically be
manufactured.
-Vn the accompanying drawings:
Fig. 1 is a perspective view of one form of
zipper embodying my invention;
50 Fig. 2 is an enlarged section on the plane
of Fig. 1 showing the slider lock in neutral posi-
tion;
Fig. 3 is a fragmentary section corresponding
to Fig. . showing the slider fully locked;
55 . Fig. 4 is a view correspondirg to Fig. 3 showing

3
the pawl in one fully unlocked position, the posi-
tion it takes when the zipper is being closed;
Fig. 5 is a view corresponding fo Fig. 3 showing
the pawl in another fully unlocked position which
it takes when the zipper is being opened by the
pull tab;
Fig. 6 shows the pawl in a third fully unlocked
position, which it takes when released by an ex-
cessive opening force;
Fig. 7 is a section of the zipper taken on the
line 7--7 of Fig. 3;
Fig. 8 is a section corresponding to Fig. 3 show-
ing a modified ïorm of the invention in the fully
locked position; and
Fig. 9 is a section corresponding to Fig. 2 show-
ing a second modified form, the pawl being in
the neutral position.
Referring to Fig. 1, the chain of the zipper has
a pair of stringers i6 each consisting of a beaded
fabric tape 2! to the beaded edge 22 of which is
Sëcued. a row of irïtêrlocking elements 23. A
lidér 24 for 0pening ad closing the zipper has
the usUaI Y-shaped chnnel or passage, the end
of wtiich is indîcaed t -5 in' Fig. 2 and the
ro'gs section of which is indicted at -5 in Fig. 7.
-li pagsgge sur0unds the chain. The passage
ï fbriied by an Upper plate 26 of the slider, a
loWê plate 27 and a wedge 26. The slider, when
meVed upward on the Chain, that is to the left
as seen  in Fig. 1, progressively interlocks the two
r6v of elemerïts to close the zipper, and when
inved in the opposite direction, progressively
dier/ggges the rows to open the zipper. The
stidgr is moved in either direction along the
ctiiri  bY a pull tab or handle 29, slidably se-
cured fo the upper plate by an- èlongated bail or
10op  and so çrranged tht it Can pull the
-slideç .from èither end: As so far described the
onstruction and operation Of the zipper are wel!
Ilowrl.
.]:n the stider exemplifying my invention, the
upPer plate is provided with an opening 32 (Fig.
2). A iock is housed under the loop 36 and ar-
ranged so that it can project through ttïe Open-
ing.32 into the channel -. Preferabty the upper
plate bas two simflar openings 2- and  sep-
araed by a shelf or bearing 38, as seen best in
Fig.-. The locking member consists Of a cen-
trgl shaft 4 from which depend a pair of legs
g2, . projecting ito the openings. The shaft
filÏs tie space between the shelf 3 and the cap
or leop 3. It has an opposite pair of rounded
faces 44- (Fig. 2) so that it functions as a round
shaft, turning through a limited angle in the
bearing formed by the Shel 33 and the rounded
end  of a depression 4 in the cap. The shaft
can also s!ide a!ong the shelf 38. The leg 42
form's the active locking pawl, the les 4 serving
te guide the shaft on its bearings and to prevent
binding. The Side walls 46 (Fig. 7) and thè end
waH 6 (Fig. 2) of the cap form a well which
confines a spring 2 which bears against a fiat
face 64 of the shaft, urging the shaft to the left
against the concave face 4. The end of the
sprflig may be so formfl and positioned that
it normally holds the lock with the pawI in the
angular position shown in Fig. 2, which is the
nomal or neutral position of the lock.
The pawl, in its neutral position, is inclined
With respect to a line perpendicular fo the chan-
nel-. The pawl is long enough to project slightly
into the channel in this position, just enough
for the point te contact an interlocking e!ement
if the sliler moves in either direction. Whenever
he i0k is in the neutral position, and the s!ider

2»599078
4
tends to more in the opening direction without
the control of the pull tab, the  first interlocking
element which contacts the locking point swings
the pawl to the left, rotating the shaft clock-
5 wise about its conter and bringing the pawl into
the position (shown in Fig. 3) perpendicular to
the channel, causing the locking point to project
further into the channel between the interlock-
ing elements. In this position the pawl is
lo stopped or held by the wall of the opening 3-, in
which position the lock is held by the spring
blocking passage of the interlocking elements
through the slider, thus preventing movement of
the sli.der to open the zipper.
15 When it is desired to open the zipper, the pull
tab - is pulled to the right as seen in Fig. 5.
This slides the shaft 4} to the right, compress-
ing the spring, and since the locking point
is held by the interlocking element with which
0 it is in contact, the lock rotates clockwise as
belote, inclining the pawt in the opposite direc-
tion to the line which is perpendicular to the
r0wg of elements through the axis of the- shaft
as shown in Fig. 5, far enough .to remove the
2 lo-cking point from the path of the interlocking
elements. This permits the slider to be slid to
the right and thus to open the zipper.
While the slider cannot be freely moved fo
open the zipper except under control of the pu]l
0 tab, as wfll be explained,-the s!ider can be freely
moved to close the zipper. Whenever the slider
tends to move to the left, as seen in the draw-
ings, each interlocking element strikes against
the back of the locking point and rotates the
35 shaft  counterclockwise, compress.ing the
spring very slightly and swinging the leg 2 into
the inclined position shown in Fig. 4, in which
the locking point slides over the interlocking
elements and permits the slider to move in the
40 closing direction. Since the spring bears against
the fiat face  the only compression of the
spring during this latter rotation is caused by
the slight distance that the lower edge of this
fiat face moves during rotation of the lock from
45 the position of Fig. 2 to that of Fig. 4. This is
a very slight am0unt and produces a very slight
restoringforce on the lock, reducing to a mini-
mum the dragging force of the locking point on
the interlocking elements when the zipper is
50 being closed, and preventing appreciable wear of
the locking point.
It will be observed that in moving into locked
position the pawl is rotated clockwise about a
fixed pivot remote from the channel, so that its
55 points swings from right to left and in swinging
carrîes itself ïarther into the channel, until
stopped where it projects the maxîmum dstance
into the channel. However, in moving fo
locked position the pawl rotates clockwise about
ç0 the interlocking elements and the formerly fixed
pivot is moved laterally to pivot the lock about
an interlocking element and swing the opposite
end of the pawl from left to right, dragging the
pawl out from between the elements. In so doing
65 thepawl is inclined oiposite to the inclination in
the neutral position.
As this opposite inclination away from the per-
pendicular increases, it becomes easier ïor e
force of the interlocking element acting on the
i0 locking point to force the locking Point out of
the channel. This is important in unlocking the
sI.ider when it is locked against a vint heavy
forcê tending to pull the stringers apart. For,
d.ue to the arrangement of the parts, thiS force
? tending fo open the zipper assists the unlocking

2,599,078

action rather than opposes it, once the pawl has
been started away from ifs perpendicular posi-
tion. Thus in Fig. 3, if there is a strong open-
ing force on the slider hot due fo the pull tab,
the interlocking element in contact with the lock
pushes hard to the left, bearing against the lock-
ing point with a force whose direction is repre-
sented by the vector 600 in Fig. 3. The shaft 400
is held against movement away from the inter-
locking elements by the cap -00. This causes the
inclined face of the locking point 500 to urge the
interlocking elment against the lower wall
of the slider. The wall reacts against the element
and causes if fo press against the lock in a di-
rection perpendicular fo the wall 27, as repre-
sented by the force vector 6|. The resultant of
these vectors 600 and 00| is the resultant total force
exerted by the interlocking element on the lock-
ing point. This is represented by the vector 002
which must be perpendicular fo the face of the
locking point. The component 00| in this posi-
tion of the lock is perpendicular fo the cap and
is completely absorbed or opposed by the bottom
wall of the depression 44 of the cap. The com-
ponent 0000 is perpendicular fo the face of the
opening 32 which stops the lock. Thus no move-
ment is produced. However, as soon as the lock
is moved by the pull tab slightly away from the
perpendicular toward the position of Fig. 5, the
component 6| assists in pushing the shaft fo the
right a]ong the cap. Increase in the inclination
of the leg increases the effectiveness of this com-
ponent 6 | in sliding the shaft along the cap, thus
the very force which he]d the lock against ifs
stop can now tend fo slide the lock along the
stop and a]ong the cap, and assist the pull tab
in unlocking the slider.
This condition makes if .possible fo provide a
s]ider in which the lock is automatica]ly re-
leased by being moved away from the positive
stop by an excessive force tending to open the
zipper without the control of the pull. This is
useful, for example, wherever if is desired fo bave
the zipper open without damaging itself af the
occurrence of an opening force which would de-
stroy the tape of the zipper or damage the ar-
ticle fo which the article is applied.
The comportent 600 is opposed by an equal forc.e
63 effected bF the wall of the opening 32. This
force is in the opposite direction fo the force
and if occurs af the point 65 where the lock con-
tacts the stop. If this point is hot in line with
the force 600, as is indicated in Fig. 5, a couple
will be set up tending to rotate the lock clock-
wise toward the position of Fig. . Since as
practical marrer, if ma: be desirable to have
some clearance between the inner surface of the
top wing and the top face of the interlocking
element, there wi]l be some offsetting of the lines
of the forces 600 and 63. Thus a couple will be
set uP which tends fo move the lock from the
fullF locked position fo unlocked .position. This
couple is opposed bF the force of the spring
acting ai a distance equal fo the perpendicular
distance from the effective line of action ' of the
spring fo the point of contact between the lock
and the inter]ocking element. If the amount of
th couple exceeds the moment of the sprin.g, the
lock will be rotated clockwise into the position
of Fig. 6 and thus be withdrawn from locking
position. The moment of the couple, fo any
given opening force on the slider can be reg-
ulated within limits b: determining, the point
of contact between tle lock and the Stop, and
the moment of the spring can .be regulated b:

6
changing the force of the spring. Thus, the
point at which the safety opening .of the zipper
occurs can be determined when the s]ider is con-
structed.
5 In some applications of the invention if may be
desirab]e fo have clearance between the slider
and the interlocking elements and yet have a
positive lock which will hot be released by any
unintended opening force, however great. Such
l0 a lock slider is il]ustrated in Fig. 8. This is con-
 structed as previously described except that the
lock has a locking surface 700 which engages a
corresponding surface 72 on a relieved portion
behind the stop ïormed by the opening 32. The
]5 surface 72 is formed at an angle which will pre-
vent its forming a point bearing for any part of
the surface 700. Therefore any tendency of the
interlocking element to rotate the pawl out
the perpendicular position and into unlocked po-
20 sition tends fo produce c]ockwise rotation about
the edge of the opening 32 at 74. Such clock-
wise rotation is prevented by the projecting sur-
face 6 engaging the surface 72. Preferably the
surface 700 is parallel fo the inclined face of the
25 locking point 500 and inclined about 45 ° fo the
axis of the pawl, and the surface 72 is inclined
45 ° fo the rows of elements, so that 72 is par-
allel fo the face of 56 when the paw] is per.pen-
dicuiar fo the rows and in locking position. The
30 surface 7{} does hot extend toward the inter-
locking elements beyond the line, perpendicular
fo the surface 72 and passing through the point
of contact between the Pawl and an interlocking
e]ement. Beyond this line the projection carry-
35 ing the surface 700 is preferably rounded or re-
lieved on a radius hot greater than the distance
to the point of contact between the interlocking
element and the pawl, so as hot fo bind when
the pull tab tends fo unlock the slider after the
40 manner indicated in Fig. 5. The lock swings
clockwise about the interlocking element and the
rounded point oî the Projection carrying the
surface 00 clears the surface
In Fig. 9 is illustrated a modified form of the
45 invention in which the spring 52 holds a modified
form of lock yieldingly 'against an inclined stop
900. The locking pin 9 has a head 92 which has
a fiat side adapted fo rest on the sloping surface
900. The spring 52 is placed in a bore or recess
5O and rests in an annular recess
positiordng pin 95 on the head of the lock. The
spring substantially fills the bore so as fo hold the
head against the side of the bore, as well as
against the inclined stop 900. Otherwise the lock
• 55 of Fig. 9 operates like that of Figs. 2 fo 5, but the
inclined stop tends fo hold the lock somewhat
more positively in ifs neutral position whenever
the slider is hot locked nor being either closed or
opened by the pull. When the lock rotates fr0m
60 neutral into locked position, if pivots about the
fulcrum formed by the edge 96 of the incllned
support, this fulcrum being in the line perpen-
dicular fo the rows of elements which passes
through the stop formed by the wall of the open-
65 ing 32, insuring that when the lock reaches the
stop, if wfll be perpendicular fo the rows of ele-
ments and project the maximum distance into the
passage.
I claire as my invention:
70 1. A zipper comprising in combination a pair
of rows of interlocking elements,a slider, having
a passage for the elements, the passage diverging
atone end of the slider and being adapted when
moved in one direction along the rows to inter-.
.75 lock the rows to:c!ose the zipper and when rnoved

2,599,078

7
in the opposite direction to disengage the rows
fo open the zipper, a lock pivoted in the slider
and having a locking end, resilient means nor-
mally and yieldingly holding the lock in a position
with its axis inclined in one direction away from
a line perpendicular fo the rows and with its lock-
ing end projecting into the path of the elements,
a pivot shaft on the lock, a pivoting and sliding
support for said shaft adapted to maintain the
shaft a constant distance ïróm the passage, said
resflïen means normally holding said pivot shaft
on said pivoting and sliding support and the lock
being rotatable on said support toward a position
perpendicular fo the rows to project the locking
end frther into the path of the elements in re-
sponse to initial uncontrolled opening movement
of the sliler, a stop between the ends of the lock
for stopping the lock when substantially perpen-
dicular fo the rows to prevent ïurther opening
movement of the slider, and a second pivot on the
lock for contacting the stop.
2. A zpper comprising in combination a pair
of rows of interlocking elements, a slider having
a passage for the rows and adapted when moved
in one direction along the rows to interlock the
rows to close the zipper and when moved in the
opposite direction fo disengage the rows to open
the zipper, a lock in the slider having a locking
point atone end and a pivot shaft at the other
end, a pivoting and sliding support for the shaft
adapted to maintain the shaït a constant distance
from the passage, resilient means for yieldingly
holding the pivot shaft on said support and
the lock normally in a position inclined in one
direction fo a line perpendicular fo the rows with
the locking point projecting into the path of the
elements, the lock beLg rotatable in one sense
about the axis of the pivot shaït into a position
perpendicular to the rows to project the locking
point further into the path of the elements, and
a stop for stopping the lock in said perpendicular
position the zipper including means for rotating
the lock in the same sense about the stop into a
position inclined in the opposite direction to the
perpendicutar to remove the locking Point from
the path of the elements.
3. A zipper comprising in combination a pair
rows of interlocking elements, a slider having a
passage for the elements, the passage diverging af
one end of the slider and being adapted when
moved in one direction along the rows to interlock
the rows to close the zipper and when moved in
the opposite direction to disengage the rows to
open the zipper, a lock in the slider having a lock-
ing end, the lock.being rotatably supported in the
slider, resilient means yieldingly holding the lock
normally positioned with its axis inclined away
ïrom a line perpendicular fo the rows and pointing
toward the rows and toward the convergent end
of the passage and with the locking end project-
ing into the path of the elements, the lock being
rotatable from said inclined position toward said
perpendicular line whereby the lock is adapted to
be rotated to project the locking end farther into
the path of the elements in response to initial
uncontrolled opening movement of the slider a
pivot on the lock between the ends of the lock, .a
stop on the slider for the pivot for stopping the
lock when substantially perpendicular to the rows
to prevent further opening movement of the
slider, tle lock being adapted to be rotated about
the pivot on the stop by excessive force tending
fo. move the slider .in the opening direction to
iclin :the lock away from the perpendicular and

8
remove the locking end from the path of the
elements.
4. A zipper comprising in combination a pair
of rows of interlocking elements, a slider having
5 a passage for the elements the passage diverging
at one end of the slider and being adapted when
moved in one direction along the rows to interlock
the rows fo close the zipper and when moved in
the opposite direction to disengage the rows to
open the zipper, a lock having a pivot mounted
in the slider remote from the rows and having a
locking end, resilient means yieldingly holding
the lock normally positioned with its axis inclined
away from a line perpendicular to the rows and
pointing to the rows and fo the convergent end
of the passage and with its locking end projecting
into the path of the elements, the lock being
rotatable in one sense about said pivot toward
the perpendicular line fo project the locking end
farther into the path of the elements in response
to initial uncontrolled opening movement of the
slider, a second pivot on the lock adjacent the
rows and a stop on the slider adjacent the passage
for stopping the second pivot when the lock is
substantially perpendicu]ar fo the rows, the lock
being rotatable in the saine sense about the second
pivot on the stop by excessive force tending to
more the slider in the opening direction fo incline
the lock away from the perpendicular and to
emove the locking end from the path of the
elements.
5. A zipper comprising in combination a pair
of rows of interlocking elements, a slider having
a passage for the elements, the passage diverging
35 at one end of the slider and being adapted when
moved in one direction along the rows to inter
lock the rows to close the zipper and when moved
in the opposite direction to disengage the rows to
open the zipper, a lock in the slider having a
40 lockirg end, resilient means Fieldingly holding
the lock normally positioned with its axis inclined
away from a line perpendicular fo the rows and
pointing toward the rows and toward the con-
vergent end of the passage and with its locking
45 end projecting into the path of the elements, a
pivot shaït on the lock, a pivoting and sliding
support for the shaft adapted to maintain the
shaft a constant distance ïrom the passage, said
resilient means normally holding said pivot shaft
50 on said support the lock being rotatable on said
support from said inclined position toward said
perpendicular line whereby the lock is adapted fo
be rotated to project the locking end farther into
the path of the elements in response to initial
5 uncontrolled opening movement of the slider, a
second pivot on the lock and a stop on the slider
between the ends of the lock for stopping the
pivot when the lock is substantially perpendicular
fo the rows, the lock being rotatable and slidable
60 on the second pivot on the stop in response to
excessive force tending to more the slider in the
opening direction for sliding the sh.aft along the
support to incline the lock in the opposite direc-
tion to the perpendicular and fo remove the lock-
65 ing end from the path of the elements.
6. A zipper comprisin in combination a pair
of rows of interlocking elements, a slider having
a passage for the elements and adapted when
moved in one direction along the rows to inter-
7O lock the rows to close the zipPer and when moved
in the opposite direction to disengage the rows to
open the zipper, .a lock in the slider having a
- locking POint at one end and a pivot shaft at the
other end, a pivoting and sliding support for the
75 shaft in the slider adapted to maintain .the. shaït

10

15

2O

25

3O

9
a constant distance from the passage, resflient
means yieldingly holding the pivot shaft on said
support with the lock in a position norrnally in-
clined in one direction with respect fo a line per-
pendicular fo the rows and having the locking
point projecting into the path of the elements,
the lock being rotatabIe in one sense about the
pivot suppo]'t into .a position perpendicular fo the
rows to project thelocking point farther into the
path of the elernents, rneans on the s]ider for
stopping the lock substantially perpendicular to
the rows, the lock being rotatable in the_ sarne
sense about the stopping means to a position
inclined in the opposite direction to the per-
pendicular fo remove the locking point from the
path of the elements.
VE. A zipper comprising in combination a pair
of rows of interloc]dng elements, a slider having
a passage for the elements, the passage diverging
atone end of the slider and being adapted when
rnoved in one direction along the rows to inter]ock
the rows to close the zipper and when moved in
the opposite direction along the rows fo disengage
the rows fo open the zipper, a locking rnember in
the slider resflient means yieldingly holding the
locking member in a position norrnally incIined
fo a line perpendicular to the rows and pointing
toward the rows and toward the convergent end
of the passage, a locking point on the locking
member, a pivot on the locking member rernote
from the passage, a pivoting and sliding support
on the slider for said pivot, sai.d resilient rneans
yieldingly holding said pivot on said support the
locking member being rotatable in one direction
about the pivot fo move the locking mernber to-
ward said perpendicular line and fo rnove the
Iocking point toward the center of the passage
and between the inter]ocking elements, a bearing
surface on the locking rnember adjacent the lock-
ing point adapted fo contact an inter]ocking e]e-
ment when the locking point is so placed between
the interlocking elernents, a stop on the slider
adapted fo contact the lock at a point spaced
axially frorn said bearing surface when the lock
is substantially perpendicutar to the rows whereby
opening force on the slider sers up a couple on the
lock between the bearing surface and the stop,
said couple tending fo rotate .the lock in the op-
posite direction away from said perpendicular
line.

10
8. A zipper comprising in combination a pair
of rows of interlocking elements, a slider having
.a passage for the rows, the passage diverging af
one end of the slider and being adapted when
5 rnoved in one direction along the rows fo interlock
the rows to open the zipper and when moved in
the opposite direction along the rows fo disengage
the rows fo open the zipper, a locking member
on the slider having a locking end, resilient
I0 rneans yieldingly holding said ]ocking mernber
norma]ly positioned with its axis inclined away
from a line perpendicular to the rows and point-
ing toward the rows and toward the convergent
end of the passage and with the locking end pro-
i.5 jecting into the path of the elements, a pivot
shaft on the locking mernber, a pivoting and slid-
ing support fo]" said shaft adapted fo maintain
the shaft a constant distance from the passage,
said resilient means yie]dingly holding said pivot
20 shaft on said support the locking rnernber being
rotatab]e on said support toward said perpendicu-
lar line to project the locking end farther into
the path of the elements in response fo initial
uncontrolled opening movement of the slider, a
2.5 stop on the slider for stopping the lock when
axis is substantially perpendicular fo the rows,
the zipper including means for sliding and rotat-
ing the shaft on the support to incline the lock
in the opposite direction away from said per-
30 pendicular line and thus to remove the locking
end from the path of the elernents.
GIDEON SUNDBACK.

35

4O

45

EFEENCES CITEK}
The following references are of record in the
fi!e of this patent:
UNITED STATES PATENTS

Number
2,222,986
2,271,141
2,289,585
2,301,792

Number
417,781
512,643

Naine Date
Poux ............... Nov. 26, 1940
Lange .............. Jan. 27, 1942
Marinsky ........... July 14, 1942
Plumley ............ Nov. 10, 1942
FOREIGN PATENTS
Country Date
Great Britain ............ of 1934
Great Britain ............ of 1939