Patent GB-1334903-A (GB)
Title: Electropneumatic brake-control apparatus for a rail vehicle
IPC: B60T13/66
Filed: 1971-04-19
Abstract: 1334903 Compressed air systems for rail vehicles KNORR-BREMSE GmbH 19 April 1971 [3 April 1970] 26390/71 Heading F2F An electropneumatic braking system for a rail vehicle with a filling pipe 1 and a main air train pipe 2 incorporates a brake control valve 5 controlled by the pressure in the train pipe 2 and having a maximum pressure limiter 6 and a minimum pressure valve 7, an auxiliary air reservoir 8, a brake cylinder 9, a train category change-over unit 10 and an electropneumatic unit 11 which comprises a braking electromagnetic valve device 72 and a releasing electromagnetic valve device 87 operable respectively by energization of cables 4 and 3. The brake control valve 5 includes a control piston 14 separating chambers 13 and 15 and connected to a valve tube 18 permanently open at one end to an air-venting chamber 19, at its other end the tube 18 is co-operable with a double valve packing 21 to control communication to a space 20. The space 20 communicates with a chamber 41 via a conduit 42 and the chamber 41 communicates with the brake cylinder 9. The braking valve device 72 of the unit 11 has a first valve 74 operable on energization of the coil 73 to connect a venting chamber 66 and a chamber 75 which is in communication with the train pipe 2: a second valve 76 controls communication between a chamber 77 and an admission chamber 78. The release electromagnetic valve 87 includes two valves 89 and 93 which are respectively opened and closed when the coil 88 is energized. The unit 10 comprises two tappet valves 98, 99 which are manually operable by turning an operating shaft 97: when the valves 98, 99 are closed a brake throttle 100 and a release throttle 101 are rendered inoperative and braking and release operations take place with a longer time interval as may be necessary with longer trains. For pneumatically controlled braking operation the pressure in the train pipe 2 is lowered causing valve 25 to open and pressure in chamber 24 to be communicated to cylinder 9 to apply the brakes: to release the brakes regulation pressure is once again fed into the train pipe 2 and any desired braking and release stages can be adjusted by only partial fall or rise in pressure in the train pipe 2. For an electrically controlled, direct braking operation, the cables 3 and 4 are energized: consequent operation of valve device 72 opens the valve 74 to allow air to flow to the venting chamber 66 wherein it operates a piston 81 and the valve 76 to allow air to flow to the venting chamber 19 of valve 5 from a conduit 32 via a throttle 84, chamber 62 and pipe conduit 47: this air in chamber 19 flows via the valve tube 18 to the brake cylinder 9. Simultaneous operation of valve device 87 causes the valves 89 and 93 to open and close respectively and prevents compressed air flowing out of chamber 60 and through release throttle 96, 101 to atmosphere. When the desired braking stage is reached the cable 4 is de-energized and the feeding of air to cylinder 9 is interrupted: for holding the braking stage which has been initiated the valve device 87 remains energized. For electrically controlled, direct releasing action the cable 3 is de-energized, whereupon atmospheric pressure will be attained in the cylinder 9. For switching over the system to electrically and indirectly controlled two-line operation and also to pneumatic two-line operation the filling pipe 1 is filled with air of at least regulation pressure. In pneumatically controlled braking operations compressed air taken from the auxiliary air reservoir 8 for filling the cylinder 9 is constantly replenished from the pipe 1 via a non-return valve 27, and in such release operations air escapes from the cylinder 9 through the valve 64 and a valve tube 59. For electrically and indirectly controlled braking operations the cable 4 is temporarily energized and for such releasing operations the cable 3 is temporarily energized.