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■ jkp Agriculture 


Research Direction generale 
Branch de la recherche 

Technical Bulletin 1984-3E 




Construction details of 
a large forage plot 
harvester for cleanup 
and harvest of test plots 

-J . - B1BLH 

P T0M981 












Thr map on ihe cova has dots representing 
Agriculture Canada research establishments. 

Construction details of 
a large forage plot 
harvester for cleanup 
and harvest of test plots 

Experimental Farm 
Normandin, Quebec 

Report No. 216, Sainte-Foy Research Station, Quebec 

Research Branch 
Agriculture Canada 

Copies hi this publication are available from: 

Experimental Farm 

Reseait h Bran< h. Agriculture Canada 

1472 rue St-Cyrillc 

Normandin, Quebec 

(.o\\ 2E0 

Produced 1>\ Research Program Service 

! Minista ol Supply and Services Canada 1984 
Cai No A54-8 I984-3E 
ISBN 0-662-13032-4 

Vussi disponible en Irancais sons le titre 
Details de construction d'une grosse fourragire 
funn U- nettoyage et la recolte de pari flics 


Abstract iv 

1.0 Introduction 1 

2.0 The vehicle 1 

2.1 The motor 1 

2.2 The transmission 4 

2.3 The wheels 6 

2.4 The cutter control 6 

2.5 The hydraulic system 6 

2.6 The cutter 9 

2.7 The hopper 10 

2.8 Other accessories 10 

2.9 Safety features 12 

2.10 Conclusion 14 

2.11 Acknowledgments 14 



This technical bulletin provides construction details for a large forage plot 
harvester built specifically to clean up experimental plots and to take 
samples on large plots for experimental purposes. 


Le bulletin technique presente les details de construction d'une grosse 
fourragere construite specifiquement pour le nettoyage des parcelles 
experimentales et/ou pour la prise d'echantillons lorsque de grandes parcelles 
sont requises pour atteindre les objectifs experimentaux. 



To conduct forage experiments, whether they involve cultivar evaluation or 
management studies, test plots have to be planted and tended for several 
years. Replication of seedings over 2 or 3 consecutive years increases the 
number of plots that must be cut and the area that must be restored to an 
identical condition after removal of the samples used to determine yields or 
other agronomic characteristics. Cleanup of the test area after sampling 
takes a relatively long time with small forage plot harvesters, but large 
machines are very inconvenient to use for this work. For these reasons, it 
was decided to construct a large forage plot harvester that was compact, easy 
to operate, and labor efficient, and that saved time. 

There are no plans for the forage plot harvester. The purpose of this 
bulletin is to provide a reasonably detailed description of the main 
components and their operation. 


The forage plot harvester is 127.5 cm wide by 232.5 cm long. The frame of the 
harvester (Fig. 1) is made of square tubes, 5 x 10 x 0.5 cm (2 x 4 x 3/16 
inch), bent and welded into a rectangular shape, ending in a point. The 
chassis is 120 cm long by 47.5 cm wide. Pieces "d" and "e" (Fig. 1) reinforce 
the frame and support other parts of the machine. Point "a" shows the 
location of the front wheel axle, 23.7 cm from the front of the frame. The 
steering linkage arm is inserted at point "b" (Fig. 1). The front part of the 
forage harvester pivots on shaft "c", which is 3^2 cm in diameter, by means of 
two pillow blocks. The shaft also carries the sprockets that transmit power 
from the transmission to the front wheels by a chain drive. 

The structure of the mobile frame of the forage harvester is shown in Figure 
2. The cutter is attached to the mobile subframe on piece "f" using bolts 
12 x 89 mm (1/2 x 3 1/2 inches). The two pieces "g" support the hopper, and 
plates "h" secure the front part of the harvester to the shaft "c" (Fig. 1) by 
means of pillow blocks. A metal plate 19 mm (3/4 inch) thick is fitted 
between the pillow blocks and the plates "h" so that the coupling point of the 
cutter projects 5 cm beyond the chassis of the vehicle. The hydraulic 
cylinder that lifts the front of the forage harvester is attached at one end 
to a point between the metal plates "k" (Fig. 2) and at the other to the 
support "e" on the frame of the vehicle (Fig. 1). The lower part of the 
cylinder that is used to empty the hopper is attached to point "n" on the 
mobile subframe. 

2.1 - THE MOTOR 

The motor is mounted on a support that protrudes slightly from the frame at 
the right rear. The motor is a Briggs and Stratton 16 horsepower two-cylinder 
air-cooled gas motor. The electric starter, the generator, and the alternator 
are integral with the motor. The throttle is connected through a cable to a 
remote control located near the operator's seat. 


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FIGURE 2 - Construction details of the subframe of the mobile front portion 
of the forage harvester. Dimensions are given in centimetres. 

f - cutter attachment points 

g - hopper support 

h - attachment of the mobile subframe to the shaft using pillow 

k - attachment of cylinder that lifts the front of the forage 

n - attachment of the base of the cylinder that tips up the hopper 



FIGURE 3 - Mechanism for transmission of power from the motor to the 

Power is transmitted to accessories by belts from the four-belt pulley A 
(Fig. 3) fixed to the power takeoff shaft. The pulley is 12.8 cm (5 inches) 
in diameter, with a 2.5 cm (1 inch) shaft size. The innermost belt is 
connected to pulley B (Fig. 3), which is a single-belt pulley 15.3 cm 
(6 inches) in diameter with a shaft size of 1.25 cm (1/2 inch). This pulley 
powers the hydraulic system pump G. The two central belts go to pulley D of 
the DE complex (Fig. 3), which consists of two two-belt pulleys with diameters 
of 12.8 and 15.3 cm (5 and 6 inches), respectively. These pulleys transmit 
motive power to the cutter. The fourth belt, on the outside, is connected to 
a single-belt pulley C (Fig. 3) 17.8 cm (7 inches) in diameter and shaft size 
of 2.5 cm (1 inch), which provides power to the transmission. 


The transmission is a Peerless No. 2302A complete with a clutch control. It 
is attached to the triangular part of the frame of the vehicle and has three 
forward speeds and one reverse. 

A 5L-430 V-belt runs between the motor and the transmission. Tension is 
controlled through an idler pulley F (Fig. 3) acting as a clutch. The idler 
pulley is operated by a pedal (Al, Fig. 9) on the footrest, connected by a 
steel rod. The clutch pedal engages the transmission when it is pushed down. 

FIGURE 4 - Control system for the drive and for power transfer 
to the cutter. 

To change gears, the clutch is disengaged by taking one's foot off the pedal, 
which returns to its original position by means of a spring. The speed 
control is then set in the desired position and the operator presses on the 
pedal to engage the clutch. 

Independent drive on each wheel is obtained through a No. 50 chain system. A 
power sprocket H (Fig. 4) with 26 teeth and 2.5 cm (1 inch) shaft size is 
attached to the transmission shaft and connected to the KJ complex by a 
chain. Tension on the chains is maintained through an adjustable gear wheel 
attached partly under the motor support and partly under the footrest. The KJ 
complex consists of two pulleys with 36 and 30 teeth respectively and with a 
shaft size of 3-2 cm (1 1/4 inch). A grease coupling between the two 
sprockets provides lubrication. The KJ complex transmits power from the 
transmission to a 30-tooth sprocket welded to the center of the front wheel. 
This system is used again for each of the axles. (This concept is based on an 
unpublished design by G. B. Hergert, Engineering and Statistical Research 
Service, Agriculture Canada, Ottawa.) 


The front tires are 57.5 - 21.25 - 30 era (23 - 8.5 - 12 inches), whereas the 
steering tires are 41.25 - 16.25 - 20 cm (16.5 - 6.5 - 8 inches). A major 
modification should be made to the front wheels. The center of the wheel rim 
should be unwelded and reconnected to the interior edge of the rim in order to 
clear the sprocket welded to the hub of the wheel and allow the chain to go 
around without rubbing against the tire. 


The cutter control system originally consisted of two large belts that 
directly connected the power take-off of the motor to the cutter pulley. This 
system was changed after one season of tests, because the rotation of the 
cutter could not be kept constant as a result of loss of tension on the belts 
when the front part of the forage harvester was raised to make a higher cut. 
To counteract this major inconvenience and the resulting loss of efficiency, 
the system that transfers power from the motor to the cutter was modified and 
operates with the help of a neutral point located in the same axis as the 
pivot shaft of the front part of the vehicle. 

The neutral point also acts as the attachment point for the clutch mechanism 
of the cutter. This consists of two steel boxes, N and P (Fig. 4), which 
slide on two metal blocks. Movement of the boxes downward increases tension 
on two belts, which are connected to the motor and provide rotary motion to 
the cutter. The inverse movement stops the cutter rotation. The whole 
mechanism is engaged by means of a metal bar located near the steering wheel 
of the vehicle and connected by a rod V (Fig. 8). 

The clutch block of the cutter, made up of two pulleys M and L (Fig. 4), with 
double belts and diameters of 15.3 and 12.8 cm (6 and 5 inches) respectively, 
makes it possible to alter the rotary speed of the cutter by changing pulley 
M or L to a smaller or larger diameter depending on whether a reduction or 
increase of maximum speed is desired. In addition, depending on requirements, 
installing the system at a neutral point provides a way of adjusting the 
cutting height without loss of rotary power to the cutter. A double-belt 
pulley of 21.25 cm (8.5 inches) diameter, fixed on the axis of the cutter, 
completes the system. 


One hydraulic system is used to operate four cylinders. All the components 
are connected by flexible hydraulic hose of medium pressure. 

The power steering consists simply of a steering control mechanism at the base 
of the steering column and a hydraulic cylinder Q (Fig. 5) that can stretch 
19 cm (7.5 inches). The system was taken from the power steering used on some 
models of Ford cars. The steering control and the cylinder are connected by a 
flexible hydraulic hose to a reservoir R, which is a rectangular column with a 
capacity of 2.5 L. 

FIGURE 5 - Part of the hydraulic system used for power steering. 

Cylinders S and T (Fig. 6) empty the hopper and raise the front part of the 
forage harvester, respectively. These two cylinders are 37.5 cm (15 inches) 
long and 2.5 cm (1 inch) in diameter and have a maximum stretch of 25 cm 
(10 inches). 

One end of cylinder S is connected to the mobile subframe at point "n" 
(Fig. 2), and the other end is connected to the hopper 37.5 cm (15 inches) 
from the end of it. The bottom of the hopper is fastened to the mobile frame 
by a large hinge. Cylinder T is attached at one end to bar "e" (Fig. 1) 
welded to the vehicle frame and at the other end to the front of the machine 
between the steel plates "k" (Fig. 2). Two springs U (Fig. 6) were installed 
under the mobile subframe of the forage harvester to allow the cutter to 
follow the terrain more closely and to provide better traction for the wheels 
by shifting the weight of the mobile part to the frame of the vehicle. 

The final component of the hydraulic system consists of a cylinder 60 cm 
(24 inches) long with a diameter of 2.5 cm (1 inch) having a stretch of 40 cm 
(16 inches). One end is connected to the hopper and the other end to the 
hopper gate. This cylinder opens and closes the hopper gate (Fig. 7). The 
oil pressure necessary to activate all the components of the hydraulic system 
is provided by pump G (Fig. 3). 

FIGURE 6 - Components of the hydraulic system that lifts the front part of 
the vehicle and empties the hopper. 

FIGURE 7 - Components of the hydraulic system that opens the hopper for 

FIGORE 8 - Design of the control systems of the forage harvester. 

The design of the control systems of the forage harvester is shown in 
Figure 8. The metal lever V with a knob on top, located near the steering 
wheel, is used to engage and disengage the rotary cutter. The plate W is a 
small dashboard with an ignition key unit, a choke control, and an ammeter. 
The throttle control is on the shaft supporting the steering wheel and the 
seat. The steering wheel operates the power steering control at the foot of 
the steering column, whereas the other hydraulic components are connected to 
two valves X and Y (Fig. 8) attached to the top of the hydraulic oil 
reservoir. The hydraulic valve X is equipped with two double-action levers. 
One of these levers is used to open and close the gate of the hopper, and the 
other is used to lift the hopper and empty it, and bring it back to its 
original position. The hydraulic valve Y (Fig. 8) operates the cylinder 
control used to raise the front part of the forage harvester. 

The transmission box is located under the motor support. The pedal Al 
(Fig. 9) is used to operate the idler pully F (Fig. 3), which puts tension on 
the belt to engage the transmission. The pedal Bl (Fig. 9) is connected by a 
metal rod to a band brake attached to the transmission to stop the forage 


The front view of the forage harvester (Fig. 10) shows the cutter, which is 1 
m wide and 45 cm in diameter in extension. A shaft 3.2 cm (1 1/4 inches) in 
diameter covered by a cylinder of 10 cm (4 inches) makes up the core of the 
cutter. Attached to it are 9-cm (3-1/2 inch) metal supports in pairs, to 
which the blades are fixed. 

FIGURE 9 - Position of the clutch and brake pedals. 

The blades are of the "Mott" type and are 3.2 cm (1 1/4 inches) wide by 12.5 
cm (5 inches) long. An adjustable roller 10 cm (4 inches) in diameter is set 
beneath the back of the cutter to control the height of cut. 

Two screens Dl and D2 (Fig. 10) with openings 1 x 2 cm (3/8 x 3/4 inch) and 
3 x 16 ram (1/8 x 5/8 inch) respectively are placed on the hopper to allow air 
to pass through and out. 

2.7 - HOPPER 

The frame of the hopper is made of square steel tubes, 2.5 x 2.5 cm (1 x 1 
inch). A metal sheet 1.56 mm (1/16 inch) thick is bent and welded inside the 

The interior dimensions and the gate, as well as the depth of the hopper, are 
shown in Figure 11. The gate moves on a large hinge. The capacity of the 
hopper cannot be determined from the dimensions as shown, because the open 
gate hides the upper part of the hopper (Fig. 14), which is 10 cm (4 inches) 
above the gate hinge. The capacity of the hopper is about 0.4 cubic metre (14 
cubic feet) . 


A rear view of the forage harvester (Fig. 12) shows the location of other 
accessories such as the 12-V battery (El), the gas tank (Re), and the controls 
(Co) necessary for the operation of the harvester. 


FIGURE 10 - Front view of the forage harvester showing the cutter. 

FIGURE 11 - Interior dimensions of the hopper in centimetres, 


FIGURE 12 - Rear view of the forage harvester 

Other less important accessories have been added: a drawbar (Bt) and a 
toolbox (Fl). The shape of the gas tank available allowed us to attach it to 
the support column of the seat and the steering wheel. However, any other 
models or shapes of gas tank could be installed by lengthening the footrest 
slightly toward the rear, without extending it beyond the vehicle frame, and 
by setting the gas tank partly under the seat in place of the toolbox. 


The right side of the forage harvester (Fig. 13) shows the locations where the 
protective screens are installed. A screen Gl covers the motor tailpipe to 
prevent burns. Screens G2 and G3 protect the belt systems and minimize the 
possibility of injuries. 

The left side view of the forage harvester (Fig. 14) shows the attachment of 
the roller (Ro) under the rear of the cutter and also the bolts used (Bo) to 
adjust the height of cut. A trapdoor (Tr) allows the operator to check the 
level of material in the hopper. 


FIGURE 13 - Right side view of the forage harvester. 



FIGURE 14 - Left side view of the forage harvester 



After 3 years, during which we tested, adjusted, and modified the forage 
harvester, we can confirm that it has attained its objectives. This very 
compact, large forage plot harvester can be transported long distances in the 
box of a truck or in a small trailer. We have been able to reduce by 
one-third the time required to clean up test plots after harvesting. Also, 
the forage harvester can be used to take samples if the experiment requires 
data from large plots. The physical demands on the operator are minimal 
because all the controls are hydraulic, which permits the vehicle to be 
operated continuously for longer periods of time. 


The authors wish to thank Drs. C. Gagnon and C. Richard for their advice in 
preparing this paper and Mr. J. St-Cyr, photographer and designer, for his 
collaboration in the photography.