GB588022A - Improvements in or relating to the steering of vehicles - Google Patents

Abstract

588,022. Steering motor vehicles. DUFOUR, L. Jan. 25, 1945, No. 2050. Convention date, Jan. 24, 1944. [Classes 79 (ii) and 79 (v)] A tractor or like vehicle is steered in the normal way up to a wheel deflection of about 25 to 30 degrees, after which further rotation of the steering wheel automatically disconnects the front wheels from the steering mechanism and applies a brake to the driving wheel inside the turn. In Figs. 1 and 2 the front axle 6 is hinged at its centre to the chassis 5 and carries at its ends fixed vertical spindles 7 on which are pivoted arms 8 connected by track rod 23 and actuated by a steering arm 20. The arms 8 carry at their forward ends spindles 10 to which are secured inclined arms 11 carrying the wheels. The spindles 10 carry at their upper ends discs 13 each slotted at 14, the slot normally being engaged by a spring pressed bolt 15 to lock the spindle, whereby normal steering is effected through the steering wheel 27, worm and wheel 26, 25, drop arm 22, rod 24 and steering arm 20, the wheels turning about the spindles 7 disposed vertically over the point of contact between the wheels and the ground. The fixed spindles 7 carry at their upper ends double-sided cams 19 each engaged by a roller 18 on the end of the bolt 15, the cams being so shaped that after a front wheel deflection of 25 to 30 degrees from straight ahead, each roller 18 is caused to withdraw the bolt 15 from the slot 14 in disc 13 and so disconnect the front wheels from the steering gear and allow them to pivot about the spindles 10 castor fashion. At the same time, gears 28, 29 have rotated the arm 31 so far that it contacts arm 32 or 32' freely mounted on spindle 30, and further rotation of the steering wheel and arm applies one or other of the brakes 35, 35<1>, whereby turns of short radius may be effected. In a modified form, Figs. 5 and 9, the front axle 6 projects forwardly at its ends and carries vertical spindles 38 to the bottom ends of which are attached the inclined arms 11 carrying the wheels. Each spindle 38 has secured thereto one half of a dog clutch 40, - the other half 41, which is mounted freely on the spindle 38, being normally kept in engagement with the first half by the spring 43 whereby the wheel responds to -movements of the steering arm 42 to give normal steering. Secured to each end of the axle 6 is a cam 45 engaged by a pair of rollers 44 mounted on the clutch member 41 and arranged so that after the wheels are denected by more than 25 to 30 degrees by the normal steering mechanism, the two halves of the dog clutch are separated, as in Fig. 9, and the wheels left free to follow further turning movements caused by braking. With the arrangement shown in Fig. 5, since the steering head is not vertically over the point of contact between wheel and ground, normal steering movements cause the whole front of the tractor to move sideways.