Four-wheel drive lift truck

Claim 2

A lift truck comprising: a frame including a forward U-shaped portion comprising a pair of substantially parallel, longitudinally extending arms and a transversely extending base interconnecting the rear ends of the arms; a pair of front steeriNg wheels mounted at the front ends of the arms of the U-shaped portion of the frame for supporting the front end of the lift truck; a linkage including portions extending along the arms and a portion extending along the base of the U-shaped portion of the frame for maintaining the steering wheels in a parallel relationship with respect to the frame; a prime mover mounted on the frame to the rear of the base of the U-shaped portion thereof; transmission means operatively connected to the prime mover; a pair of non-steerable rear wheels operatively connected to the transmission means and hence to the prime mover for actuation thereby; drive means extending along each side of the frame for selectively drivingly coupling the rear wheel on each side of the lift truck to the front wheel on the same side of the lift truck so that the lift truck is propelled by means of both the rear wheels and the front wheels; said drive means on each side of the frame comprising a chain and sprocket drive including: a first sprocket mounted for rotation with one of the rear wheels; a cross shaft comprising interconnected second and third sprockets; a first chain extending around the first and second sprockets; a fourth sprocket operatively connected to the front wheel on said one side of the frame; and a second chain extending around third and fourth sprockets; the U-shaped portion of the frame, the front steering wheels, the linkage and the drive means thereby defining an entirely opened area between the arms of the U-shaped portion of the frame; a boom pivotally supported on the base of the U-shaped portion of the frame for vertical manipulation in said open area; and an operating compartment positioned on the frame to the rear of the base of the U-shaped portion thereof and including means for manipulating the linkage to control the orientation of the front steering wheels.

Claim 3

The lift truck according to claim 1 wherein at least a portion of the drive means extending along each side of the frame extends through and is enclosed by housing means comprising portions of the frame of the lift truck.

Claim 4

The lift truck according to claim 1 wherein the transmission means comprises hydrostatic drive means including hydraulic pump means driven by the prime mover, hydraulic motor means operatively connected to the output of the hydraulic pump means, and means drivingly connecting the rear wheels of the lift truck to the hydraulic motor means.

Claim 5

The lift truck according to claim 3 wherein the hydraulic motor means comprises dual hydraulic motors each having an output connected to one of the rear wheels.

Claim 6

A lift truck comprising: a frame including a forward U-shaped portion comprising a pair of substantially parallel, longitudinally extending arms and a transversely extending base interconnecting the rear ends of the arms; a pair of front steering wheels mounted at the front ends of the arms of the U-shaped portion of the frame for supporting the front end of the lift truck; a linkage including portions extending along the arms and a portion extending along the base of the U-shaped portion of the frame for maintaining the steering wheels in a parallel relationship with respect to the frame; a prime mover mounted on the frame to the rear of the base of the U-shaped portion thereof; transmission means operatively connected to the prime mover; a pair of non-steerable rear wheels operatively connected to the transmission means and hence to the prime mover for actuation thereby; drive means extending along each side of the frame for selectively drivingly coupling the rear wheel on each side of the lift truck to the front wheel on the same side of the lift truck so that the lift truck is propelled by means of both the rear wheels and the front wheels; said drive means on each side of the frame comprising: a gear mounted for rotation with one of the rear wheels; a cross shaft comprising interconnected gears; a first drive shaft having gears at its opposite ends mounted in mesh with the gear of the rear wheels and one of the gears of the cross shaft; a gear operatively connected to the front wheel on the same side of the lift truck as the rear wheel; and a second drive shaft having gears at its opposite ends mounted in mesh with the other gear of the cross shaft and the gear of the front wheel; the U-shaped portion of the frame, the front steering wheels, the linkage and the drive means thereby defining an entirely opened area between the arms of the U-shaped portion of the frame; a boom pivotally supported on the base of the U-shaped portion of the frame for vertical manipulation in said open area; and an operating compartment positioned on the frame to the rear of the base of the U-shaped portion thereof and including means for manipulating the linkage to control the orientation of the front steering wheels.

Claim 7

A lift truck comprising: a frame including a forward U-shaped portion comprising a pair of substantially parallel, longitudinally extending arms and a transversely extending base interconnecting the rear ends of the arms; a pair of front steering wheels mounted at the front ends of the arms of the U-shaped portion of the frame for supporting the front end of the lift truck; a linkage including portions extending along the arms and a portion extending along the base of the U-shaped portion of the frame for maintaining the steering wheels in a parallel relationship with respect to the frame; a prime mover mounted on the frame to the rear of the base of the U-shaped portion thereof; transmission means operatively connected to the prime mover; a pair of non-steerable rear wheels operatively connected to the transmission means and hence to the prime mover for actuation thereby; drive means extending along each side of the frame for selectively drivingly coupling the rear wheel on each side of the lift truck to the front wheel on the same side of the lift truck so that the lift truck is propelled by means of both the rear wheels and the front wheels; said drive means on each side of the frame comprising: a gear mounted for rotation with one of the rear wheels; a cross shaft comprising interconnected gears; a first drive shaft having gears at its opposite ends mounted in mesh with the gear of the rear wheels and one of the gears of the cross shaft; a gear operatively connected to the front wheel on the same side of the lift truck as the rear wheel; and a second drive shaft having gears at its opposite ends mounted in mesh with the other gear of the cross shaft and the gear of the front wheel; the U-shaped portion of the frame, the front steering wheels, the linkage and the drive means thereby defining an entirely opened area between the arms of the U-shaped portion of the frame; a boom pivotally supported on the base of the U-shaped portion of the frame for vertical manipulation in said open area; and an operating compartment positioned on the frame to the rear of the base of the U-shaped portion thereof and including means for manipulating the linkage to control the orientation of the front steering wheels.

Claim 8

The lift truck according to claim 5 wherein at least a portion of the drive means extending along each side of the frame extends through and is enclosed by housing means comprising portions of the frame of the lift truck.

Claim 9

The lift truck according to claim 5 wherein the transmission means comprises hydrostatic drive means including hydraulic pump means driven by the prime mover, hydraulic motor means operatively connected to the output of the hydraulic pump means, and means drivingly connecting the rear wheels of the lift truck to the hydraulic motor means.

Claim 10

The lift truck according to claim 7 wherein the hydraulic motor means comprises dual hydraulic motors each having an output connected to one of the rear wheels.