Patent GB-1114182-A (GB)
Title: Improvements in or relating to vacuum brake arrangements for railway vehicles
IPC: B60T13/46
Filed: 1965-11-30
Abstract: 1,114,182. Vacuum brake system. COMPAGNIE DES FREINS ET SIGNAUX WESTING- HOUSE. 30 Nov., 1965 [1 Dec., 1964], No. 50859/65. Heading F2F. A vacuum brake arrangement for railway vehicles comprises a vacuum pump, driver's brake valve A, a train pipe 4 controlling the brakes, an electropneumatically operated double cut out 5 having independent pistons 103, 104 slidably mounted in a bore in a body to provide an inlet chamber 106 connected to the pump, an end chamber 110, chamber 112, either of the latter being connectable by electrically operated valves 111, 113 to the inlet chamber or to atmosphere, the piston 104 forming part of a small-capacity valve and the piston 103 forming part of a large-capacity valve, these valves controlling passage between the inlet chamber and an output chamber connected to the train pipe, the arrangement also comprising a control duct 7 connecting the pump with the inlet chamber, a control arrangement comprising an adjustable device 9 adjustable according to the brake valve handle position together with a selective electrical contactor which supplies current to various members, particularly the electrically operated valves of the double cutout, and a member 11 which compares the train pipe vacuum with the adjustable device and a member 72 which enables the control duct 7 to be connected to the atmosphere, a pneumatic braking relay 114 which compares the duct pressure with that in the train pipe and a member 127 which enables the train pipe to communicate with the atmosphere. Operation.-The positions I, D, M, S, U of controller A relate to conditions of cut-out, release, running, apply brake, and emergency stop. The compression of spring 9 reduces as the controller handle moves from M to S. At M the spring compression corresponds to a 50 cm. vacuum and leads 176, 177 are energized, the valves 111 and 173 then closing their " atmosphere " ports while valve 113 opens to atmosphere. Small capacity valve 109 of the double cut-out 5 then connects the suction line 6 to the train pipe 4 and valve 173 connects the control duct 7 to the suction line through a calibration hole 8. As long as pressures in pipes 4 and 7 are substantially equal, valve 72 in controller A and valve 127 in cut-out 114 are kept closed by their diaphragms and spring 9 until the vacuum in the train pipe reaches the chosen value (50 cm.) after which the control duct pressure beneath diaphragm 66 overcomes spring 9 and valve 72 opens to allow air to enter duct 7, and the increased pressure under diaphragm 123 opens valve 127 to decrease the vacuum in the train pipe. Moving the handle towards " S " reduces the compression of spring 9, diaphragm 66 and valve 72 rise to admit air to duct 7, diaphragm 117 and valve 127 rise to admit air to the train pipe and reduce the vacuum therein. Quick release.-Movement of the controller from " S " to " M " causes the vacuum in duct 7 to increase, the time delay device 158 operating to close contacts 160, energize line 175 and close contacts 188 to speed up the vacuum pumps. Valve 113 is also energized to connect chamber 112 of cut-out 5 to the suction line and large capacity valve 108 opens to rapidly increase the train pipe vacuum. On equalization of pressures at diaphragm 116 (through restriction 167) contacts 160 reopen and the system returns to its former state. At braking position " S " all leads are deenergized and valve 173 admits air to duct 7 and closes off branch 6.1 of line 6 which is itself cut off from the train pipe by cut out 5, as valves 111, 113 are de-energized and connected to atmosphere. Valve 127 opens the train pipe to atmosphere. At release position D all leads are energized. Suction line 6 is connected to control duct 7 through valve 173 and to the train pipe 4 through large-capacity valve 108, valves 111 and 113 being energized. Contacts 188 close and the pumps run at high speed to establish the full 50 cm. vacuum in the train pipe. At emergency stop position " U " a large valve (78) in the controller (Fig. 2, not shown) opens to connect the train pipe to atmosphere. Lines 175-177 are energized, as in the braking position " S " and valve 127 opens to atmosphere. At cut-out position I leads 175-177 are deenergized and the system corresponds to the emergency stop position except that valve 78 is closed. The driver's valve is fitted with detent mechanism and has a rotatable stop which can lock the valve in its cut-out position. A valve 126 is provided in the braking relay 114 to nullify its action during double heading or when the locomotive is uncoupled. Modifications are described wherein the brake release relay 158, the braking relay 114 and the control arrangement 3 comprise electrical and electronic components.