Patent GB-316532-A (GB)
Title: Improvements in and relating to angle cock devices
IPC: B60T17/04
Filed: 1928-04-30
Abstract: 316,532. Westinghouse Brake & Saxby Signal Co., Ltd., (Westinghouse Air Brake Co.). April 30, 1928. Fluid-pressure. - Valves or cocks for controlling the flow of fluid through a conduit and particularly angle cocks such as are provided at the ends of the sections of train-pipe of fluid pressure brake apparatus on railway vehicles have associated therewith an auxiliary valve subject to the pressure conditions in the conduit and controlling a bye-pass around the main cock so that the flow of fluid in the conduit necessary for the operation of the brakes is not prevented even if one or more of the cocks should accidentally be closed. As shown in Fig. 1, there is provided in addition to the usual cock 2 with passage 3 and handle 17, a bye-pass 8, 9 controlled by a piston 10. With the train pipe charged and the cock 2 open as shown, both the upper and lower faces of the piston 10 are subject to fluid pressure through passages 15, 13 and 8, 9 respectively. The piston is thus seated by the spring 14 and the passage 8, 9 closed. If, however, the cock is closed, the passage 13 and piston chamber 12 are vented through an exhaust port 16 by the passage 15 and the pressure still acting on the under face of the piston raises it to connect the passages 8, 9. At the end of the train the cock 2 is closed and the part 5 of the pipe and thus the main area of the under face of the piston are open to atmosphere; and the spring 14 is sufficient to hold the piston in the seated position against the fluid pressure still acting on the central area. In another construction, Fig. 5, when as in the case of the intermediate cocks there is pressure in the train-pipe on both sides of the cock 2, the under faces of the piston 10, 18 are subject to the fluid pressure through the passages 8, 19 and a restricted passage 29, and as the upper piston chamber 12 is open to atmosphere by the port 31 the piston is held in the raised position in which it opens the byepass 8, 19 whether the cock 2 is open or closed. At the end of the train however where the cock is closed and the end 5 of the pipe and thus the under face, of the piston 10 is open to atmosphere, the piston is held in the lower position by the spring 14 thus disconnecting the passages 8, 19 except as regards the restricted passage 30, the continued escape of fluid through which is insufficient to interfere with the operation of the brakes. Choke plugs 20, 21 provided in the passages 8, 19 prevent a sudden reduction of pressure in the train-pipe for applying the brakes from causing the piston 10 to assume the lower position before the pressure reduction has been transmitted to the part of the train-pipe, in rear of a closed cock. When cutting off a vehicle or part of a train on which the brake system is charged, the cock 2 on the ends of each adjoining vehicle is closed and a plunger 28 is depressed during the uncoupling operation to vent the piston chamber 23 to atmosphere, by a valve 25, thereby depressing the piston and disconnecting the passages 8, 9. In a further construction, Fig. 6, the chamber 12 above the piston 10 is normally vented through passages 38, 31. The chamber 23 below the piston is connected to the train-pipe by the passage 8 and thus in the case of cocks other than the end cock, the piston assumes the raised position in which the bye-pass 8, 9 is established whether the cock 2 is closed or not. By depressing a plunger 28 the upper piston chamber 12 is disconnected from the vent port 31 and is connected by a passage 37 to the! train-pipe 6 and the piston is thus depressed to close the bye-pass 8, 9 preparatory to uncoupling. When the uncoupling has been effected, the piston remains in the lower position after the plunger 28 has been released, since the part 4 of the train-pipe to which the piston chamber 23 is connected is then open to atmosphere. When connecting a vehicle with a charged brake. system to one in which the system is uncharged, before opening the cock 2 on the charged vehicle, after coupling up the vehicles, the plunger 28 is depressed to depress the piston 10 and in this position the piston uncovers a restricted passage 36 so that the fluid can pass from the charged to the uncharged train-pipe sections through the passage 37, 38, 36, 34. 39, 8, thus preventing a sudden reduction of the pressure in the trainpipe section on the charged vehicle.