Abstract: The differential steering drive for a tracked vehicle includes a drive differential interconnecting the drive shafts for the tracks and a steering differential for superimposing additive and subtractive rotations to the tracks for steering and pivot turning. In the preferred embodiment for high speed tracked vehicles, the drive differential is an all-gear no-clutch type limited-slip differential, and the steering differential is an unlimited-slip differential. The differentials are arranged to provide no-slip track operation traveling in straight paths or when steering so long as at least one track has traction. In another embodiment for pivot-turning slow-moving off-road vehicles, both the drive differential and the steering differential are all-gear no-clutch type limited-slip differentials.

Abstract: The track design for use with a tracked vehicle includes a cantilever cut made down into the outward side of each tread just outboard of the position where the inside of the track contacts the outboard edge of the tread of the outer wheel of each pair of track-supporting dual wheels. This cut significantly reduces lateral “roll-out” of the guide lugs from between the dual wheels when traversing uneven surfaces. When the outer edge of the track passes over sharply uneven terrain, this cut in the tread allows the outer edge of the track belt to lift away from the flat main surface under the wheels. Thus the interior surface of the track maintains contact with both tires of each pair of dual wheels by reducing twisting of the track belt that may cause the guide lugs to tip out of the mating surfaces formed between the dual-wheel pairs.

Abstract: The transmission includes an orbital gear complex in combination with a variable hydraulic pump and motor. The input to the transmission is increased in speed by the orbital gearing such that, when the pump and motor are not operating, the orbiter is stationary, and the orbital gearing produces an overdrive condition. A gear reduction is accomplished by rotating the web with the web-rotating device, providing a high gear reduction. The pump and motor are preferably long-piston hydraulic machines with infinitely variable swash plates. The hydraulic machines preferably have wobblers stabilized by full gimbals and hold-down plates with elongated holes for the long pistons to eliminate possible impacts between the hold-down plates and the head ends of the long pistons when the swash-plates are at or near their maximum angle of inclination.

Abstract: Smaller and lighter hydraulic pump/motors provide remarkably improved volumetric efficiency with pistons having body portions substantially as long as the axial length of the respective cylinders in which they reciprocate. A plurality of respective lubricating channels form a single, continuous lubricating passageway entirely within the cylinder block and not connected by either fluid “input” or fluid “output” passageways, being replenished solely by a minimal flow of fluid to and from the valve end of each cylinder and passing between each respective cylindrical wall of each cylinder and the axial cylindrical body of each respective piston. Several embodiments are disclosed in combination with various spring-biased hold-down assemblies. The preferred embodiment includes a fixed cylinder block, a roller bearing mounting between the wobbler and rotor of a split-swash plate, with piston shoes contacting the wobbler directly without any intermediary apparatus.

Abstract: The modular transmission uses only a pair of small and light hydraulic machines of remarkably improved volumetric efficiency with pistons having body portions substantially as long as the axial length of the respective cylinders in which they reciprocate. The two hydraulic machines operate in a closed loop, one being used as a pump driven by the vehicle's engine, and the other used as a motor. Each machine has a fully articulatable swash plate. By computer control, the angles of the swash plates of the two machines are infinitely varied to provide an appropriate optimum ratio of engine/wheel speed for all conditions from start-up, city driving, hill climbing varied according to load and steepness, and over-drive for highway. This complete vehicle operation is attained while the vehicle's engine continues to operate at relatively constant speeds and relatively low RPM.