Patent GB-578375-A (GB)
Title: Clutch and brake control system for vehicles
IPC: B62D11/08
Filed: 1943-06-29
Abstract: 578,375. Fluid - actuated valves. BOLDT, W. F. June 29, 1943, No. 10529. [Class 135] [Also in Group XXXI] In a control-system for a vehicle having a clutch-and-brake-controlled driven-member on each side, the clutches are controlled by fluid motors directly connected to hand-operated main valves, and the brakes are controlled by fluid motors connected to a third main valve through selector means controlled by the clutchoperating valves. In the construction shown, the supply of compressed air from a tank 1, Fig. 1, to right and left clutch-operating cylinders 3, 4 is controlled by a valve 5 having two hand-levers 16, 18, and the air supply to right and left brake-operating cylinders 27, 28 is controlled by a pedal 30 and valve 29. Alternative control means for a second driver are provided by means of a clutch valve 5<1> with hand-levers 16<1>, 18<1> and a brake valve 71 having a hand-lever 72. The main clutch valve 5 comprises two rotary plugs 11, 12, Figs. 2 and 3, respectively fixed to the hand-levers 16, 18. In the normal vertical position of the handlevers, the pipes 8, 9 leading to the clutch cylinders 3, 4 are connected to exhaust ports 26 in the valve and both clutches are engaged: If the hand-lever 18 (say) is rotated clockwise, as viewed in Fig. 3, through 90 degrees, the exhaust port is closed and the air-inlet port 21 from the supply pipe 7 is connected through a bore 24 to the pipe 8 so that air is admitted to clutch cylinders 3 and the right-hand clutch is disengaged. Similarly, if the hand-lever 16 is operated, the left-hand clutch is disengaged and, if both hand-levers are operated, both clutches are disengaged. The brake pedal 30 actuates a valve 29 connected by a pipe 31 to the supply tank 1 and by a pipe. 32 to an automatic valve 36 which is connected by pipes 33, 34 to the brake cylinders 27, 28 and is controlled by the pressure in the clutch cylinders 3, 4. The valve 36 is so arranged that (1) with the hand-levers 16, 18 in their normal positions and both clutches engaged, depression of the brake pedal 30 admits air to both pipes 33, 34 and applies the brakes on both sides, (2) if one handlever 18 .(say) has been operated and the righthand clutch disengaged by cylinder 3, depression of the brake pedal admits air only to the righthand brake cylinder 27 so as to apply that brake and cause the, vehicle to make a sharp turn to the right; a similar sharp turn to the left is made if the hand-lever 16 is operated, and (3) if both clutches are engaged and both brakes applied by depression of the pedal 30, then operation of either hand-lever 16 or 18 disengages the corresponding clutch and releases the brake on the opposite side so that a sharp turn is made. The valve 36, Figs. 4, 6 and 7, comprises four spring-loaded valves 52-55 operated by cams 39, 40 on a shaft 38 normally kept in the position shown. by centring spring plungers 67; 68 acting on a lever 64 on the shaft. In this position the valves 52, 53 are open and 54, 55 are shut, so that chamber 46 connected by pipe 32 to valve 29, is in communication with chambers 42, 43 respectively connected by pipes 33, 34 with the brake cylinders 27, 28. Thus if pedal 30 is now depressed both brake cylinders are operated. When either handlever 16 or 18 is rotated to supply air to the corresponding clutch cylinder 4 or 3, air is simultaneously supplied through a branch pipe 65 or 66 to the valve 36 to act on a piston 63 and rock the shaft 38 in one direction or the other. Thus, if the left-hand clutch cylinder 4 is operated air is admitted through branch 65 and rocks shaft 38 clockwise, as seen in Figs. 6 and 7, so that valve 52 is allowed to close and valve 54 is opened, valves 53 and 55 being unaffected. If the brake pedal is now depressed air is admitted only to the . left-hand brake cylinder 28 through valve 53, the closed valve 52 preventing air from passing to the righthand brake cylinder. The valves 54, 55 are exhaust valves since they open on to an exhaust chamber or port 47<1>. If it is desired to control the vehicle from a second driver's position the valves 5<1>, 71 mounted on an adjustable column 70 are used, and when this is the case the other valves 5, 29 are put out of action by rotating the hand-levers 16, 18 to the dotted line position shown in Fig. 1, and by rocking the brake pedal 30 to operate a valve 76, the pipes 8, 32 being thereby shut off both from the tank 1 and the atmosphere. The valves 5<1>, 71 are connected to the tank 1 by a pipe 7<1> and to the valve 36 by a pipe 74.