Patent GB-917478-A (GB)
Title: Improvements in distributors for compressed fluid braking apparatus
IPC: B60T15/30
Filed: 1961-08-22
Abstract: 917,478. Fluid pressure brakes. COMPAGNIE DES FREINS ET SIGNAUX WESTINGHOUSE. Aug. 22, 1961 [Sept. 15, 1960], No. 30246/61. Class 103 (1). A distributer in or for braking equipment has a quick service valve 25 housed in a differential piston 28 subject, when the distributer is in the release condition, to control reservoir pressure, to brake pipe pressure and quick service bulb pressure. In operation of the brakes a fall in pressure in the brake pipe CG is transmitted to the chamber situated above the diaphragm piston 1 through annular space 7, aperture 60, valve chamber 25, channel 8 and channel 9. The piston 1 of the principal pile is put out of balance and is drawn upwards which causes piston 2 to lift the valve member 25 by means of push-rod 26. The channel 9 is connected to the quick-service bulb PA which is open to atmosphere, by channel 8, open valve member 25, channel 52 and open valve 50. The air in channel 52 communicates by a channel 63 with the chamber below valve 40 which due to the drop in pressure in the brake pipe is closed by spring 64. This isolates channel 9 from the channel 32-43, ending at the control reservoir RC. The drop in pressure in the brake pipe is steep and because of this the moving part of the principle pile rises upwards to its full extent so as to move valve 5 off its seat 6. Air from auxiliary reservoir RA consequently flows through the valve 15 to the channel 14, the open valve 5-6 and the chamber 19 to the brake cylinder CF. When the pressure reaches such a value which produces a force on the inshot valve piston 22 greater than that produced by the spring of the piston, the latter rises and closes valve 15. The supply to the brake cylinder is then made through aperture 65. When the fall in pressure in the channel 17 is sufficient control piston 18-47 drops to its full extent so as to cut off the channels 43-32 and establish the connection between the channel 29 and the quick service bulb PA. This causes piston 28 to be pushed upwards by the brake pipe pressure. The air admitted to the brake cylinder CF passes through the aperture 12 to the channel 11 which ends above the diaphragm piston 2 and when this effect surpasses the effort in the opposite direction on piston 1 the moving part of the principal pile descends and the valve 5-6 closes. The push-rod 26 likewise descends to allow valve 25 to close. Any increase in pressure in the brake pipe CG after application of the brakes causes the moving part of the principal pile to descend to close valve 5-6 and open valve 5-4 which vents the brake cylinder to atmosphere through channel 20 and aperture 21. When the pressure in the brake cylinder falls to a sufficiently low level the moving part of the principal pile rises again causing the valve 5-4 to close without opening the valve 5-6. During the whole of the time when the release of the brakes is taking place the pressure in the brake pipe CG passes through annular space 7, aperture 61, channel 37, open valve 36, apertures 39, 42, channel 17, open valve 35, channel 62, open valve 16, channel 14 and the open valve 15 to arrive at the auxiliary reservoir which is thus recharged. When the pressure under the piston 33 reaches a certain value the valve 35 closes and the supply to the auxiliary reservoir RA is solely through the aperture 38. As the pressure in the brake pipe rises the piston 44-47 will at one stage rise to put channel 52 in communication with the quick service bulb through the open valve 50. When the pressure in the brake pipe approaches its original value the brake cylinder is completely vented to atmosphere through the open valve 5-4 and the diaphragm piston 44-47 moves upwards to put channels 43-32 and 29 into communication. The piston 24 descends thus restoring the seat of valve 25 to its initial position. The spring 67 maintains the device in the brakesreleased position.