Patent GB-555407-A (GB)
Title: Improvements in or relating to steering gear for vehicles
IPC: F15B21/00
Filed: 1941-10-20
Abstract: 555,407. Steering vehicles by de-clutching and braking. CLAYTON DEWANDRE CO., Ltd., TWEMLOW, E., and EDGE, S. H. Oct. 20, 1941, No. 13479. [Class 79 (ii)] [Also in Group XXXIV] A pair of servo-cylinders 19, 20, Fig. 1, are connected in a power-operated hydraulic circuit and a hand-actuated lever or levers 1 operates valves 10,11 controlling the flow of liquid through either or both the cylinders, said lever also controlling valves 37, 38 to interrupt the return flow from said cylinders partially or completely to cause pressure to be built up in the selected cylinder to operate the piston therein and thereby apply the corresponding brake and, if desired, disengage the clutch on one side of the vehicle to steer the latter. In the normal position shown in Fig. 1 liquid is freely circulated by a pump 15 past the valves 10, 11, through passages 30, 33, through ports 31, 34 in the hollow piston rods 25, 26 of pistons 21, 22, through grooves in the stems 35, 36 of the valves 37, 38 to a chamber 27 connected by a return pipe 28 with the pump reservoir 16. The hand lever I mounted on a fixed pivot 3 is connected by a link 4 to a floating lever 5 which is pivoted at 7 to the rod 9 of valves 10, 11 and is connected by a link 42 to a lever 39 mounted on a fixed pivot 40 and controlling the valves 37, 38. When the hand lever is rocked clockwise (say) as shown in Fig. 2 the rod 9 is pushed in to close the valve 10 and the shaft 40 is rocked to close the valve 38. The pump now supplies liquid only through the valve 11 and passage 33 to the back of piston 22 so that this piston is forced out and its rod 24 applies the corresponding steering brake and/or clutch. In the position shown in Fig. 2 the valves 10, 38 are completely closed; in intermediate positions the valve 38 would only be partly closed and the pressure in cylinder 20 would depend on the extent to which it was closed. In the construction shown in Fig. 3 two hand levers 43, 44 pivoted at 45, 46 are employed. The hand lever 43 is connected by link 47 to lever 48 which is pivoted at 7 on the valve rod 9 and is connected by link 49 to lever 50 operating valve 38. Similarly hand lever 44 is connected by link 51 to lever 52 independently pivoted at 7 and connected by link 53 to lever 54 controlling valve 37. When either hand lever is rotated in the direction of the arrow associated therewith one of the valves 10, 11 is closed and also the corresponding valve 37, 38. If both hand levers are operated simultaneously the pivot pin 7 remains stationary and both valves 37, 38 are closed so that both pistons 21, 22 are operated to apply both brakes &c. Modifications are described in which (1) Figs. 5 and 6 (not shown), two hand levers are employed each independently linked to one of the valves 37, 38, and each also connected by separate links to a single lever controlling the two shut-off valves 10, 11, and (2) Figs. 7-10 (not shown), two hand-operated plungers are provided each acting on a floating equalizing lever one end of which controls a stop valve 10 or 11 and the other end controls a throttling valve 37 or 38.