Patent GB-162753-A (GB)
Title: Improvements relating to fluid pressure braking apparatus
IPC: B60T13/68
Filed: 1920-01-30
Abstract: 162,753. Westinghouse Brake Co., Ltd., and Rendell, A. W. Jan. 30, 1920. Fluid-pressure.-Failure of the current in any one of the control valve magnets or it may be of the fluid pressure supply, in making an electrically controlled application of an electropneumatic brake, causes the train-pipe to be vented to give the usual pneumatic application. The system shown in Fig. 1 comprises a combined driver's valve and switch 3, 8, an electric application valve 16, controlling air supply to the brake cylinder 1 from the main reservoir pipe 6 and an electric release valve 21 adapted to close the brake cylinder exhaust pipe 60 from the triple valve 2. Included in the circuit of the valves 16, 21 on each vehicle is the control magnet 56 of a switch 59 in the circuit of an interlock train-wire 12 connected by wire 25 to a valve 23 adapted to connect a pipe 33 either to atmosphere when de-energized or to the main reservoir pipe 6 when energized. In electric application and holding positions of the valve and switch 3, 8, the pipe 33 is connected to the automatic train-pipe 4. In all positions of the valve and switch 3, 8 other than the release and running position I the conductor 24 from the interlock valve 23 is connected by switch contact 26 to the source of current 9. The train-wire 12 is connected to the return wire 13 at the rear of the train by a switch 61 which may be combined with a valve for cutting off the driver's valve at that end from the pipe 6. Hence if the current fails in any one of the valves 16, 21 in either the electric holding or application position of the valve and switch 3, 8, the circuit of the valve 23 is broken and the train-pipe 4 thereby vented. The operations effected in the various positions of the valve and switch 3, 8 are as follows : I, Running and release, all the electric circuits are open and the train-pipe 4 is connected to the main reservoir pipe 6 through the valve 3 in the usual way; II, electric holding, the train-wire 11 is energized thereby closing the contacts 55 by the relays 58 and energizing the valves 21 to close the exhaust pipe 60; III, electric application, the train-wire 10 is energized to close the circuit of both the valves 16, 21 through the contacts 53 thereby supplying the brake cylinder through the pipe 6 and reducing valve 17; in the lap and pneumatic application positions IV, V the train-wire 11 is energized as in position II to close the valves 21 and the switches 59 of the train-wire 12 but in positions IV, V the driver's valve cuts off the train-pipe 4 from the pipe 33 of the valve 23; in the emergency position VI both an electric application by the valves 16, 21 and a pneumatic emergency application by the triple valves 2 is effected. According to Fig. 3, the valve 21 instead of directly controlling the -triple valve exhaust is adapted when energized to admit air from the main reservoir pipe 18 to a pneumatically actuated valve and switch 27, of which the valve controls the triple valve exhaust and the switch being in the circuit of the interlock train-wire 12. Hence the valve 23 will be opened by failure of the air supply to the brake cylinder as well as of the current. The combined valve and switch 27 is shown in Fig. 4. When air is admitted by the valve 21 and pipe 18 to the chamber 40 the piston 41 overcoming the spring 63 engages the contact 44 on the piston rod with the fixed contact ring 45 and also by the adjustable tappet 47 and plunger 48 closes the valve 49 to cut off the triple valve exhaust pipe 60 from the atmospheric outlet 51. Rapid upward movement of the piston 41 is effected by reason of the increased area of the piston reposed to pressure as soon as it has left its seating. The downward movement of the piston is accelerated by the additional escape for the air acting beneath it provided by the port 62 as soon as it has left its upper seating. The air passing through the port 62 also serves as a blow out for the arc forming at the contacts 44, 45 and vents any leakage past the seating of the piston in the lower position. Where separate train-wires are provided for the application and release valves 16, 21, separate interlock circuits connected to a common or separate interlock valves 23 may be provided. According to the Provisional Specification, the auxiliary reservoir may supply the brake cylinder in electric applications.