GB779448A - Combined automatic and straight-air fluid pressure brake equipment - Google Patents

Abstract

779,448. Fluid pressure brakes. WESTING- HOUSE AIR BRAKE CO. April 18, 1956 [May 23, 1955], No. 11768/56. Class 103 (1). A fluid-pressure brake system 1, intended particularly for a vehicle adapted for use on both rail and road comprises a brake pipe 4, a straight air pipe 71, a brake cylinder 12, and service valve means 1 operative under one condition responsively to a reduction in brake pipe pressure below a normal full charge value, while the straight air pipe 71 is vented, to provide in the brake cylinder 12 fluid at a pressure corresponding to said reduction in brake pipe pressure, and operative under another condition responsively to pressurization of said straight air pipe 71, while brake pipe pressure is at its normal charge value, to provide in the brake cylinder 12 fluid at a pressure corresponding to that in the straight air pipe 71. The distributer valve 1 thus acts in conventional manner for railway service when the brake pipe 4 is connected by its couplings 5 and 6 to the train pipe, the chamber 70 of the service valve device 16 being vented to atmosphere through pipe 71. As used for road operation, fluid pressure from the reservoir on the tractor is passed by a reducing valve 98 so that the pipe 4, as extending between the couplings 5 and 6 is kept at the normal full charge value of the brake pipe pressure. Variations of pressure in the air pipe 71 are passed to the chamber 70 and thereby deflection of diaphragm 55 cause displacements of the slide valve 77 so that the appropriate pressure is admitted to the brake cylinders 12. A form of electro-pneumatic control for the operation of the system on a train is also described.