GB903600A - Improvements relating to fluid pressure vehicle braking apparatus - Google Patents

Abstract

903,600. Fluid-pressure brakes. WESTING- HOUSE BRAKE & SIGNAL CO. Ltd. March 3, 1961 [March 3, 1960], No. 7546/60. Class 103 (1). A vehicle braking system comprises a selflapping valve producing a pressure difference in a brake cylinder proportional to an applied force, the force being translated from a pressure dependent on vehicle load, the ratio of the translation being remotely controlled other than by train pipe pressure. The passage of main reservoir pressure (or vacuum) from a passage 14 to a brake cylinder passage 17 is controlled by a self-lapping valve comprising a closure member 18, seating 12 and hollow stem 20 open at its other end to atmosphere through an exhaust choke 23. The force on the valve is determined by the relative pressures in chambers 25, 22, 29, 21 and 30 which are separated by diaphragms 24, 27 connected to the stem 20 and diaphragm 28 bearing on the exhaust end of the stem 20. The chambers 25, 22, 29, 21 and 30 are respectively connected to brake cylinder pressure, electromagnetic valve 31, electromagnetic valve 32, atmosphere and electromagnetic valve 33. The three electromagnetic valves are supplied with fluid at a pressure dependent upon vehicle load by a valve 35 fed from the main reservoir through a non-return valve 36. In a passenger vehicle the load measurement is made automatically when the doors are opened and applied to the spring seating 39 of the reducing valve 35. The electromagnetic valves are energizable by movement of the remote driver's brake valve to apply, by combination, seven different forces to the self-lapping valve for different brake application rates, these forces being dependent on vehicle load as set by the reducing valve 35.