GB771603A - Improvements relating to vehicle braking systems - Google Patents

Abstract

771,603. Controlling vehicles. WESTING- HOUSE BRAKE & SIGNAL CO., Ltd., SIMMONS, A. W. and WASHBOURNE, J. May 18, 1955 [May 21, 1954], No. 14960/54. Class 79(5). [Also in Groups XXVII and XXXIV] In a vehicle braking system wherein the braking is effected by the closing of the exhaust outlet of the engine and by fluid pressure operated braking system, a fluid pressure actuated braking mechanism is provided with a driver-operated control valve together with a fluid pressure operated device which controls the closure of the exhaust, the supply of fluid under pressure thereto being controlled by an electro-magnetically operated valve with an electrically controlled device for cutting off the fuel to the engine, the energizing circuit of the electro-magnetically operated valve and of the electrically controlled device being controlled by a switch arranged to be operated in response to the initial movement of the driver's control valve to effect the application of the fluid pressure braking mechanism. In the embodiment illustrated in Fig. 1, the compressed air brake cylinder 1 is supplied with compressed air from supply pipe 2 through driver's foot valve 3 and pipe 4. The engine exhaust is closed by a compressed air operated cylinder 5 the supply of compressed air to which and its release therefrom being controlled by an electro-magnetically actuated valve 6. An electrically actuated device, the energizing winding of which is illustrated at 8, when energized, also cuts off the supply of fuel to the engine of the vehicle. When pedal 17 is depressed to brake the vehicle through control valve 3 in the usual manner, the switch 16 is closed and the winding 15 of the relay 10 is energized to close contact 9 and effect the supply of current to windings 7 and 8. The energizing of winding 8 causes the supply of fuel to the engine to be cut off and energization of the winding 7 from the position shown to operate valve 6 to supply compressed air, via inlet 14, to the cylinder 5 and to cause closure of engine exhaust. A stop lamp 18 connected in parallel with winding 15 may be provided. Switch contacts 11 are arranged to be closed only so long as the engine of the vehicle is rotating at above predetermined low speed to prevent exhaust braking when engine is running at idling speed. An alternative braking system is shown in Fig. 2 wherein the switch 16 is replaced by a pneumatically operated switch device 20 supplied with compressed air from pipe 4 when the pedal 17 is depressed.