Patent GB-1342690-A (GB)
Title: Brake control apparatus for a pneumatic brake
IPC: B60T15/24
Filed: 1971-04-19
Abstract: 1342690 Compressed air braking systems KNORR-BREMSE GmbH 19 April 1971 [18 March 1970] 24602/71 Heading F2F A control apparatus for a train braking system permits the system to be released by a single stage or multistage operation. The apparatus comprises a change-over device 4 having a chamber 28 connected via a conduit 29 to the control chamber 12 of a triple valve 6, chamber 28 being separated from a chamber 24 by a manually operated shut-off valve 26, a chamber 16 separated from chamber 24 by a valve 22, 23 operated through a rod 15 by a piston 13 in a control space 14 and connected through a throttle 31 to the first connection point of a two-way valve 31, the control space 14 being connected through a reservoir 30 to a second connection point thereof and being separated from a chamber 20 by a check valve 21. Chambers 16 and 20 are connected by a conduit 19, which conduit is connected through a check valve 33 to a branch line 2 of the train pipe 1 which lead to admission chamber 5 of the triple valve and to an admission chamber 3 of the change over device. The brake cylinder 8 is supplied with compressed air from a reservoir 10 by way of conduit 9, triple valve 6 and conduit 7 on brake operation. Single-stage operation.  To effect brake release, valve 26 is opened by a shaft 27 to communicate chamber 24 with chamber 28. The pressure in admission chamber 3 initially causes piston 13 to open valve 22, 23 allowing compressed air in control chamber 12, maintained at a regulated pressure by a means (not shown), to flow into the control space 14 by way of conduit 29, chamber 28, valve 26, chamber 24 into the chamber 16, throttle 32, two-way valve 31 and air reservoir 30. Piston 13 thus closes the shut-off valve 23, 23, by the control space 14 pressure, once the pressure in chamber 16, reservoir 30 and control space 14 equals that in the train pipe 1 and control chamber 12. To effect braking, reduction in train pipe pressure causes a reduction in the admission chamber 5 pressure so that the triple valve 6 operates to allow braking pressure to pass from reservoir 10 to brake cylinder 8. If train pipe 1 is completely emptied for a quick braking action, when the pressure in space 14 and chambers 16 falls below that in brake cylinder 8, the two-way valve 31 is switched to disconnect space 14 from chamber 16 and connect it to conduit 7. Consequently, the control space 14 pressure is maintained at that of brake cylinder 8. On subsequent release valve 22, 23 can only be opened by piston 13 once the pressure in brake cylinder 8 is established in train pipe 1 and admission chamber 3 to bring about a levelling in pressure between chamber 12 and train pipe 1. Hence braking failure due to brake cylinder exhaust cannot occur. To rapidly recharge chamber 12 check valve 33 is provided to open by a pressure excess to permit throughflow from the train pipe 1 to chamber 16.  Multi-stage operation.  Shaft 27 is operated to close shut-off valve 26 thereby separating chambers 12 and 23 so that any displacement of piston 13 which opens or closes shut-off valve 22, 23 has no effect on the braking or brake release. Brake release in successive stages is then effected by successive pressure changes in the train pipe 1 and admission chamber 5.