Patent GB-161150-A (GB)
Title: Improvements relating to electro-pneumatic braking apparatus
IPC: B60T13/68
Filed: 1920-10-25
Abstract: 161,150. Thomas, T. H. April 2, 1920, [Convention date]. Fluid-pressure.-The electric control of an electropneumatic brake system adapted to give both a service and an emergency application is effected by only two magnet valves on each car equipment. The system may comprise quick-action triple valves subject to electric control in all electric applications or in emergency applications only the usual train-pipe pressure control being effected simultaneously or not with the electric control. The trainwires are short circuited by a break-in-two to effect an electric emergency application at the head end of the train. The car equipment shown comprises magnet valves A, B attached to a quick-action triple valve 8 and connected respectively to train-wires 5, 6 and a common return wire 7. The wires 5, 6 are adapted to be energized by a generator 1 through an overload switch 60 and the driver's switch shown developed at 2. In one arrangement the switch 2 is mounted on the spindle of the usual driver's valve for simultaneous actuation therewith, the operations effected in the several positions of the valve and switch being as follows :- Running position II : The magnets A, B are respectively energized and de-energized, Fig. 6. Air is supplied by the driver's valve through the train-pipe 10, and triple valve groove 34 to the auxiliary reservoir 13. Train-pipe air is supplied through passages 35, 29 to the chamber 28 of a valve 30 and as the magnet B is de-energized, also to the chamber 24 of this valve through the passages 36, 25 past the valve 21 of the magnet B. The valve 30 therefore assumes the upper position shown under the action of the spring 39 whereby the brake cylinder 40 is connected to an exhaust port 47 through passages 41, 42 thence to passage 43 both by choke plug 64 and also by passage 62 past check valve 65; the passage 43 connects with the exhaust port 47 through the triple valve, the passage 45 and the valve 30. The magnet A being energized permits train-pipe air to flow also by passage 36 past the valve 19 of magnet A to an emergency valve chamber 49. Service application position V. The magnets A, B are respectively de-energized and energized, Fig. 8. Energizing the magnet B vents the chamber 24 of the valve 30 past the magnet valve 20 through the port 50 so that the valve 30 assumes the lower position thereby venting the train-pipe to the brake cylinder by passages 35, 29, chamber 28 of valve 30, emergency chamber 49, magnet valve 18, check valve 53, the valve 30 and passage 43. The triple valve is therefore actuated to connect the reservoir 13 to the brake cylinder by port 56 and passage 43. The trainpipe is simultaneously vented through the driver's valve. The choke plug 64 through which the air flows to the brake cylinder prevents the trainpipe pressure reducing faster than the auxiliary reservoir pressure and thus the movement of the triple valve to emergency position. Release may be effected by moving the driver's valve and switch first to position I and then to position II. In position I the train-pipe is charged through the driver's valve to move the triple valve to release position and the magnets A, B are both energized. The magnet valve 20 being open the valve 30 remains in the lower position but the closing of the valve 18 by the magnet A stops the venting of the train-pipe. When the driver's valve and switch is moved to position II the valves on the cars assume the positions shown in Fig. 6 and the brake cylinder exhausts as described above.. A graduated release may be effected by moving the valve and switch alternately to positions I and II. In positions III and IV the electrical connections are the same as in position I, but the driver's valve is in the holding and lap positions thereof respectively. Emergency position VI. The train-pipe is opened at the driver's valve and the magnets A, B are both de-energized. The valve magnet 21. is open as in Fig. 6 so that the valve 30 is in the raised position. The de-energization of the magnet A in these conditions connects the charged emergency chamber 49 to the chamber of the quick action piston 16 through passages 48, valve 18, passages 52, 54, valve 30, and passage 57. The usual venting of the train-pipe by the piston 16 is thus effected. The air supplied to the passage 57 also moves a piston 58 and passes by passage 59 to actuate a switch 33 which short circuits the train-wires. In the event of a break-in-two of the train this ensures an electric-emergency application of the brakes on the head cars, such application being initiated by the sudden reduction of train-pipe pressure effect- .ing the quick action of the triple valve nearest the break and thereby actuating the piston 58 by air from the chamber 12. The short circuiting of the train-wires causes the overload switch device 60 to open and de-energize the wires. The piston 58 is returned by the supply to the spring side thereof of air from the brake cylinder through passage 62. The apparatus may be used without the electric control in a purely pneumatic system. Ir. a modification a plug 66 is placed in the passage 35 leading from the train-pipe instead of in a passage 67 leading from the chamber 12 of the triple valve and the electric positions of the driver's valve and switch are separate frorr the pneumatic positions so that the train-pipe pressure is not reduced in the electric service position but serves to maintain the pressure in the auxiliary reservoir through the groove 45 during the application. There may be a switch on each car equipment for disconnecting the magnets A, B from the train-wires.