GB232738A - Improvements in vacuum brakes for vehicles - Google Patents

Abstract

232,738. Dewandre, A. March 10, 1924. Fluid-pressure: hand and foot actuation; forcetransmitting mechanism.-In vacuum brakes for vehicles fitted with internal-combustion engines, of the kind described in Specification 226,670 means are provided whereby the braking effort exerted by the cylinder piston reacts upon the operating pedal. A modification of the distributor described in the above mentioned Specification is also described. As shown in Fig. 1, the piston 4 of the brake cylinder 3 is connected to the brakes by cable 5 passing over a fixed pulley 24 and a pulley 22 connected to the brake rodding 6 by a block 23, the end of the cable being attached as shown to the brake pedal 13. The latter is connected by a rod 14 to the brake rodding through a lost-motion device to which the inner member 23a of the Bowden cable mechanism actuating the distributor is attached. In the modification shown in Fig. 3, the cable 5 and rod 14 are replaced by a system of levers 29- 35, whilst in the constructicn shown in Fig. 5, the cable passes round a pulley 41 connected by a supplementary pedal 43 to the rodding 6, and round a fixed pulley 42 before being attached to a pivoted lever 40 acting on the pedal 13, which is itself pivoted on the pedal 43. In this form, the pedal 13 may be displaced relatively to the pedal 43 to effect actuation of the distributor. The latter comprises a valve 8, Fig. 6, controlling communication between the cylinder 3 and the suction pipe of the engine, on the stem of which slides a valve 9 controlling communication with the atmosphere at 7. A,spring 11 tends to hold both the valves closed and they are controlled by the Bowden mechanism 12 through a pivoted lever 10. Normally a spring 21 holds the valve 9 open and the valve 8 is closed, but movement of the lever to the right first allows the valve 9 to close and then opens the valve 8 to establish communication between the intake pipe and the brake cylinder, sc that the brakes are applied.