Vehicle suspension

The suspension includes a pair of arms independently pivoted to opposite sides of the vehicle chassis at one end for up-and-down movement, each arm rotatably carrying a ground-engaging wheel of the vehicle at its free end. Each arm extends in the same direction from its pivoted end, longitudinally of the chassis. A compression spring contacts and upwardly extends from each arm at a distance from its pivoted end, and a load transfer lever is fulcrumed at its center to the chassis; extends transversely of the latter; and its outer ends overly and contact the top of the respective compression springs. The suspension system is applicable to three- and four-wheel motor vehicles. Preferably, the arms are hollow and serve to house part of a transformation mechanism to the wheels, the latter being the driving wheels. In a four-wheel vehicle in accordance with the invention, there is further provided an additional load transfer lever disposed on each side of the vehicle chassis and extending longitudinally of the same, with their ends underlying and having a slidable connection with the first-named transfer levers adjacent the springs.

FIELD OF THE INVENTION 
The present invention relates to vehicle suspensions and, more 
specifically, to such suspensions which enable the vehicle to negotiate 
very rough and uneven ground. 
BACKGROUND OF THE INVENTION 
Tandem wheel arrangements for motor vehicles are known. However, the extent 
to which said vehicles can negotiate uneven ground, is limited. U.S. Pats. 
Nos. 2,417,019 and 2,473,519 describe vehicle suspensions for four-wheel 
vehicles in which each wheel is rotatably carried by the outer end of an 
arm, the other end of which is pivoted to the vehicle chassis. However, in 
these patents, each front wheel as well as each rear wheel are not 
independently sprung with respect to each other, but are connected by a 
common shaft. Therefore, the ability to negotiate very rough ground is 
again limited. 
OBJECTS OF THE INVENTION 
It is a general object of the invention to provide a vehicle suspension 
which enables the vehicle to negotiate highly uneven ground. 
Another object of the invention is to provide a vehicle suspension in which 
the vehicle chassis will remain substantially level while negotiating 
uneven ground. 
Another object of the invention relates to a vehicle suspension of the 
character described, which is of simple and relatively inexpensive 
construction. 
SUMMARY OF THE INVENTION 
The vehicle suspension of the invention includes, for each pair of wheels 
disposed on opposite sides of an elongated vehicle chassis, a pair of arms 
independently pivoted to opposite sides of a chassis at one end for 
up-and-down movement, and each arm rotatably carrying one of the vehicle 
wheels at the other end, each arm extending in the same direction from its 
pivoted end longitudinally of the chassis, a compression spring means 
being provided contacting and upstanding from each arm at a distance from 
its pivoted end. A first load transfer lever is centrally, freely 
fulcrumed to the chassis and extends transversely of the latter, with its 
outer ends overlying and contacting the top of the respective compression 
spring means. The vehicle may be a motor vehicle and the wheels driven, 
for instance, by a hydraulic motor carried by the outer end of each arm 
and connected to the wheel. As an alternative, the chassis-mounted motor 
may have a mechanical transmission to the driving wheels, in which case 
the arms are hollow to house a part of this mechanical transmission. 
The suspension system of the invention is applicable to a three-wheel motor 
vehicle, in which the driving wheels are mounted at the end of a pair of 
arms at the back of the vehicle, the remaining wheel being centrally 
mounted at the front of the vehicle and being steerable. The suspension 
system is also applicable to a four-wheel vehicle, motorized or not, and 
also to any vehicle having an even number of wheels disposed on each side 
of the vehicle. In such vehicles, the arms for each group of two wheels on 
the same side of the vehicle are oppositely directed longitudinally of the 
vehicle and are pivoted to the vehicle chassis at a common pivotal axis. 
Furthermore, there is provided a second load transfer lever, one on each 
side of the chassis, and extending longitudinally of the same, these 
second load transfer levers being centrally freely fulcrumed on the 
chassis with their outer ends underlying the first load transfer levers 
and having a slidable connection therewith adjacent the compression spring 
means.

DETAILED DESCRIPTION OF THE TWO PREFERRED EMBODIMENTS 
FIGS. 1 to 7 show the first embodiment of the invention, in which the 
suspension is applied to a three-wheel motor vehicle of the type including 
a chassis 1, of generally elongated shape, the front of which carries a 
centrally-mounted single ground-engaging wheel 2, which is steerable by 
means of handle bars 3. A pair of ground-engaging wheels 4 are mounted on 
each side of the vehicle chassis at the back thereof. Each wheel 4 is 
mounted at the outer free end of a suspension arm 5, the other inner end 
of which is pivoted on the vehicle chassis 1 around a transverse shaft 6. 
The two suspension arms 5 are directed longitudinally of the chassis in 
the rearward direction with respect to their pivoted end; are freely and 
independently movable for up-and-down movement at their pivotal connection 
to the chassis. 
A load transfer lever 7 is freely pivoted about a pivot 8, centrally 
thereof, at the back of vertical wall 9 of the vehicle chassis 1. Lever 7 
is free to pivot in a vertical plane transversely of chassis 1 and its 
outer ends 10 extend spacedly over an intermediate part of the associated 
suspension arms 5. A compression coil spring 11 is fixed to and upstands 
from each suspension arm 5 at a point along suspension arm 5 intermediate 
the inner and outer ends thereof and contact the underside of the outer 
end 10 of lever 7, to which it is connected. Preferably, a shock absorber 
12 is also arranged in the gap between the lever 7 and suspension arm 5, 
said shock absorber being disposed within the coil spring 11. 
As more particularly shown in FIGS. 6 and 7, means are preferably provided 
to releasably lock the load transfer lever 7 in horizontal position when 
the vehicle is level, that is in a plane generally parallel to the main 
plane of the vehicle chassis 1. These means include a downwardly-extending 
lug 13 secured to the center of lever 7 and having a hole 14 for receiving 
a locking plunger 15 slidably carried through the rearward wall 9 and 
actuated between a locking position in which the plunger 15 engages hole 
14 to prevent swinging of lever 7 and unlocking position releasing hole 14 
through the intermediary of a flexible cable 16 extending through the 
chassis and accessible at one of the handle bars 3 to remotely control the 
locking system. 
The vehicle is preferably a motor vehicle, in which case the chassis 1 
carries an internal combustion engine 17, as shown in FIG. 4. 
Engine 7 has an output shaft 18 which drives each rear wheel 4 by a 
transmission mechanism, including sprocket wheel 19 fixed to engine output 
shaft 18; a sprocket chain 20, and a sprocket wheel 21 which is keyed to 
the transverse shaft 6, common to both wheels 4 extending entirely across 
the chassis 1. As shown in FIG. 2, each end of the shaft 6, which extends 
within the associated suspension arm 5, carries a sprocket wheel 22 on 
which is trained a sprocket chain 23, also trained on a sprocket wheel 24, 
which is secured to the stub axle 25 to which the wheel 4 is secured. 
Obviously, the arm 5 is hollow to house the chain 23 and the two sprocket 
wheels 22, 24. Therefore, each rear wheel 4 is driven by the engine 17 
through a transmission system, which extends through each arm 5. The two 
wheels are yet independently pivoted to the chassis through the associated 
suspension arm 5. Although the vehicle is a tricycle, it behaves 
substantially like a motorized bicycle with sprung rear wheels. When 
negotiating a turn, the rider seated on seat 26, shown in FIG. 4, can 
cause the vehicle chassis to tilt inwardly of the curve, as shown in FIG. 
5. When negotiating a slope or an obstacle on one side of the vehicle, the 
bicycle rider can maintain the vehicle chassis upright, as shown in FIG. 
3. 
When one wheel 4 raises with respect to the chassis 1, it causes lever 7 to 
pivot accordingly and to urge the opposite wheel to move downwardly. All 
this is accomplished within the range of normal extension and compression 
of the springs and shock absorbers 11 and 12. The result is therefore that 
one obtains a relatively large range of up-and-down movement of the 
respective wheels 4. 
FIGS. 8 to 16 inclusive show a second embodiment of the invention with the 
same suspension principle and applied to a four-wheel vehicle with each 
wheel motorized. There is shown a flat chassis 30, of generally 
rectangular shape, provided with four ground-engaging wheels 31, 32, 33, 
34. Wheels 31 and 32 are disposed on one side of chassis 30, each 
rotatably carried by the outer end of a suspension arm 35, the inner ends 
of which are pivoted to the center of the chassis at a common point 
through the means of a transverse shaft 36 extending completely through 
the chassis. 
The wheels 33, 34 are disposed on the opposite side of the chassis 30 and 
are similarly rotatably mounted at the outer ends of respective arms 35, 
which are also independently pivoted to the chassis by means of the 
transverse shaft 36. 
Arms 35 extend longitudinally of the chassis in pairs and the arms of each 
pair are oppositely directed from the centrally-located transverse shaft 
36. It is supposed that wheels 31 and 33 are the front wheels of the 
vehicle, while wheels 32 and 34 are the rear wheels. A load transfer lever 
37 is associated with the arms 35 carrying the front wheels 31, 33 and a 
similar lever 37 is associated with the arms carrying the rear wheels 32, 
34. Each lever 37 extends transversely of the vehicle chassis 30 and 
pivoted intermediate its ends at 38 on a bracket 39, which is itself 
pivoted about a vertical pivot pin 40 (see FIGS. 12 and 13) upstanding 
from the chassis 30 and provided at the joint with ball bearings 41. 
Therefore, the lever 37 is free to pivot in a plane normal to the main 
plane of chassis 30 above said chassis and also to pivot in a plane 
parallel to that of said chassis. 
The outer ends 42 of each lever 37 spacedly overlie an intermediate portion 
of the suspension arms 35 and a compression spring and, preferably, shock 
absorber arrangement 43 is disposed within the gap between the outer ends 
42 and the arms 35, making a resilient connection between the arms 35 and 
lever 37. 
Pivotal movement of levers 37 about their respective pivot pins 40 allows 
the spring and shock absorber assemblies 43 to remain substantially normal 
to the respective arms 35 during the up-and-down movements of said arms. 
A pair of additional load transfer levers 44, one on each side of the 
vehicle chassis 30, are also provided. Each additional lever 44 is 
centrally pivoted at 45 to an upstanding bracket 46 secured to the chassis 
30. The outer ends of each additional lever 44 extend underneath the outer 
ends of the transverse transfer levers 37 adjacent the associated spring 
and shock absorber assemblies 43; as shown in FIGS. 8 and 9, the outer 
ends of the additional longitudinally-extending levers 44 having a sliding 
connection with the outer ends of levers 37, being slidably inserted in a 
collar 47 which is in turn pivoted about a vertical axis underneath the 
lever 37. 
Each of the four wheels 31, 32, 33 or 34 can be motorized so as to be 
driving wheels. For this purpose, each wheel can be driven by a hydraulic 
motor mounted at the outer end of the respective arms 35, or can be driven 
through a mechanical transmission connected to the output of an internal 
combustion engine, schematically shown at 48 in FIG. 9 and mounted on the 
chassis 30, and having an output shaft connected to a transmission for 
selectively driving either one of transverse co-axial shafts 36, as shown 
in FIG. 15 through the sprocket chains and sprocket wheels 49. The two 
shafts 36 are housed in a transverse box 50 upstanding from the chassis 
30, the box serving also as a support for the brackets 46 of the 
additional load transfer lever 44. As shown in this Figure and also in 
FIG. 15, each of the two arms 35, on one side of the chassis 30, are 
interdigitated at their inner end, and the two inner ends 51, 51' are 
freely pivotally mounted on the same transverse shaft 36. Each arm 35 is 
of hollow construction; the outer end of each transverse shaft 36 extends 
within the hollow arms 35 and two sprocket wheels 52, 53 are keyed 
thereto. 
As shown in FIG. 14, a sprocket chain 54 extends within each arm 35, being 
trained on one of the respective sprocket wheels 52, 53, and is trained at 
the other end on a sprocket wheel 55, which is keyed to the stub axle 56 
of the respective wheels 31 to 34. Therefore, each wheel 31 to 34 can be 
driven by the central engine 48 and this, while allowing independent 
pivotal movement of the arms 35. Also, the vehicle can be put in reverse 
due to the chain-tightening arrangement of FIG. 14. More particularly, the 
top and bottom runs of the driving sprocket chain 54 is in meshing 
engagement adjacent each sprocket wheel 52 or 53 and sprocket wheel 55, 
with two idle sprockets 57 mounted on a common slide member 58 freely 
slidable and guided in a vertical guide track 59 fixed within the arm 35. 
The two idle sprockets 57 maintain the sprocket chain 54 in taut 
condition. In FIG. 14, the top run of the chain is the one under tension, 
that is it is the driving run, while when the rotational direction of the 
sprocket 52 or 53 is reversed, the bottom run becomes the driving run and 
is straightened out while the return top run takes an angular position. 
In accordance with the invention, the suspension is such that the four 
wheels always remain on the ground, even when negotiating high obstacles 
and even when one obstacle is on one side of the vehicle and the other on 
the other side of the vehicle, as diagrammatically shown in FIG. 16. 
Yet the chassis 30 remains substantially level. As in the previous 
embodiment, raising movement of, say, the front wheel 31 on one side of 
the chassis 30 causes lowering of the front wheel 33 on the opposite side 
of the chassis through the action of the front load transfer lever 37. The 
spring and shock absorber assemblies 43 remain within their normal range 
of extension and contraction, despite large angular movement of the arms 
35. 
The front-to-back load transfer levers 44 serve to stabilize the chassis 30 
in the longitudinal direction, since, when a front wheel moves downwardly, 
the associated rear wheel will move upwardly. Therefore, with the system 
of transverse and longitudinal load transfer levers, the vehicle chassis 
30, including any passenger compartment A mounted thereon, as shown in 
FIG. 11, will tilt through a minimum degree both longitudinally and 
transversely, despite highly-uneven ground.