GB1261436A - Drive and steering mechanism for vehicles - Google Patents

Abstract

1,261,436. Differential drive for steering. A. O. SIREN. 3 July, 1969, No. 33562/69. Heading B7H. [Also in Division F2] In a combined variable-ratio drive and differential steer arrangement for an amphibious vehicle, a pair of expanding pulley gears have driving pulleys 19 splined on a common input shaft 17, driving through V-belts 20 complementary pulleys 21 on separate aligned halfshafts 22 driving wheels on opposite sides of the vehicle, so that by adjusting the gears simultaneously in opposite directions, by turning a steer-wheel 31, the vehicle is steered, whilst adjustment in the same direction by a lever 77, Fig. 6, provides drive-ratio adjustment and declutching, with the belts resting on idler rollers 85 at maximum opening of the input pulleys 19. In each gear the pulley flanges of both the input and output pulleys are simultaneously and positively adjusted axially in opposite directions by levers 38, 55, secured to meshing toothed wheels 54 for opposite swing, the inner levers 38, 38A being of T-form with transverse arms 39, 39A respectively (overlapped in the equalized position shown), attached at their remote ends 42, 42A to endless chains 41, 40, one crossed, tracking idle sprockets 34 on a bar 35A, and sprockets 32 on a steer-shaft 33 carrying the steer-wheel 31, turning which latter thereby adjusts the gears oppositely for steering the vehicle. Equalized adjustment for clutching and ratio shift is as follows. The steer shaft 31 is carried vertically on a longitudinal bar 74, Figs.. 3 and 6, slidable in a fixed guide 75, and carrying at its other end the idler-sprocket bar 35A. Sliding the bar 74 longitudinally by the ratchet-held lever 77 carries the entire chain and sprocket assembly with the bar, thus effecting equalized adjustment of the pulleys. Whip of the drive belts 20 is prevented by a pair of rollers (92), Fig. 7, not shown, pressed against the outer surface of the upper run of each belt by a common spring (90) acting through a roller-support beam (87). The gear input shaft 17 is driven by a chain 16, Fig. 2, and each half-shaft 22 drives through one chain 24 a ground-engaging wheel 11, and through a chain 26 a second ground-engaging wheel 11A, which latter drives through a chain 29 a third and foremost ground-engaging wheel 118 arranged slightly higher than the other two, to pack snow ahead of the other wheels and to facilitate planing in water.