GB509454A - Improvements in and relating to endless track mechanism - Google Patents

Abstract

509,454. Endless-track vehicles ; steering- mechanism for cycles. MERCIER. A. May 17, 1938, No. 14674. Convention date, April 5. [Classes 79 (i) and 136 (i)] An endless-track steerable unit for a cycle or tractor comprises a front roller 1, Fig. 3, and a rear roller 4 for the track 6, a pair of intermediate rollers 2, 3 and means for unequally distributing the load upon said intermediate rollers in such a manner that when the unit is under traction maximum pressure is exerted on the ground at a point which is made to coincide with the steering axis of the unit so that a minimmn effort is required to effect the steering. The rollers 2, 3 are mounted. on the ends of a beam 11 having unequal arms, the beam being pivoted at 14 to a spring 15 shackled at its ends to a pair of arms 7 mounted on the end rollers 1, 4. The bearing 12 for the pivot 14 is connected to the arms 7 by a radius rod 8, and the beam 11 is fixed to an arm 10 connected by links 9 to a slide 13 which carries the front roller axle 17 and slides in the front ends of the arms 7, the result being that the endless track 6 is maintained under constant tension as the rollers 2, 3 rise and fall together or rock about the pivot 14. In applying the invention to a cycle as shown in Figs. 7 and 8, the motor unit 25 is so situated that its C.G. passes through the steering axis a, b, which, as stated above, passes through the point of maximum ground pressure of the track. The motor unit is connected to the track unit at a spindle 16 and is connected to the cycle frame 28 by two pairs of links 29 so arranged that the pivot points L, M, N, O form trapeziums and points S, S<1> on the motor unit in the planes of the trapeziums remain practically unaffected when the unit is turned by handlebars 30, the points S, S<1> lying on the virtual steering axis ab.