Patent GB-1276179-A (GB)
Title: Self-driven carriage
IPC: B62D7/04
Filed: 1969-08-20
Abstract: 1276179 Motor vehicles; equalizing load on wheels HITACHI Ltd 20 Aug 1969 [28 Aug 1968 16 Oct 1968 24 Jan 1969] 41644/69 Headings B7D and B7H A self driven carriage having a load supporting bed has two pairs of wheels (3a, 3b and 3c, 3d, Fig. 17, not shown) fore and aft and two pairs of driving wheels (4a, 4b) positioned midway of the bed, all of the pairs of wheels being capable of being aligned for movement of the bed and carriage either in a direction longitudinally of the length of the vehicle or transversely of the length. In addition a steering mechanism is coupled to the wheels so that once the direction of movement of the vehicle has been so determined the vehicle can further be steered in the one direction or the other. Moreover, the fore and aft pairs of wheels can be turned to adopt a generally midway position following a circular path about the centre of the vehicle and the driving wheels although aligned longitudinally are driven in opposite directions such that the vehicle bed rotates about its central axis. The pairs of wheels are mounted on axles centrally pivoted on the underside of the loading bed, the position of each pair of wheels being determined by a unit comprising a segment gear (30a ... 30c and 31a and 31b, Figs. 9 and 17, not shown), coupled to the central vertically pivoted arrangement for each unit, and which is in engagement with a further segment gear (32a ... 32c and 33a and 33b). The latter segment gears are coupled to levers which when actuated cause the wheels to adopt their generally longitudinal or transverse directions or their midway positions for movement in a circular path. Having determined the general direction of movement, the steering mechanism is coupled through further levers to the wheels to steer the vehicle. The drive to the middle driving wheels is from an engine and transmission via a reversing mechanism and a central differential unit comprising gear drive and clutch arrangements which can be coupled or disconnected to provide forward or reverse directional movement of the output shafts or opposite rotational movement of these shafts. The shafts are coupled to differential units as the pairs of driving wheels positioned midway of the vehicle. The pairs of driven wheels are mounted on the underside of the load bed by a U-shaped support member rotatably supported in the bed and to which is attached the upper ends of hydraulic cylinders of jacks the pistons of which are coupled to a beam supporting the wheel axle and differential unit. Consequently the hydraulic cylinders may be used to raise or lower the bed to support or release a load being carried. A splined shaft serves to permit the transmission drive from the differential unit to be extended or reduced. A similar hydraulic jacking arrangement is provided for the wheels fore and aft of the vehicle. In addition the hydraulic system for the wheel suspensions is such that the front two wheel systems are interconnected and each driving wheel system is coupled to that of the rear wheel system on the same side whereby the hydraulic suspension ensures an even balance of the vehicle.