GB441880A - Improvements relating to fluid pressure braking apparatus - Google Patents

Abstract

441,880. Fluid-pressure brakes. TOMLINSON, A. V., 65, Victoria Street, Westminster.-(Compagnie des Freins Westinghouse ; Sevran, France) July 27, 1934, No. 22001. [Class 103 (i)] Release of fluid - pressure brakes is accelerated by temporarily maintaining an abnormal train pipe pressure controlled by a valve influenced by the pressure in a chamber which is brought to an abnormal pressure during brake application and restored to normal during brake release. The pressure in this chamber may be the pressure in a brake cylinder or may be train pipe pressure which is increased or decreased on brake application. The abnormal pressure is supplied by a feed valve 4 controlled by a valve 31 controlled by diaphragms 22-24. Chamber 21 below diaphragm 24 is always maintained at normal train pipe pressure by a reducing valve 29 and a pipe 28. Pressure fluid from the brake cylinder 8 supplied by the pipe 27 to the chamber 20 between the diaphragms 23, 24 opens the valve 31, which when the driver's valve is in running and release position vents chamber 10 through pipes 25, 16 and the driver's valve to the train pipe 5. The piston 9 and slide valve 14 of the valve 4 are raised by fluid from main reservoir 2 which passes through ports 34, 35 of the slide valve to the pipe 16 and the train pipe to produce a temporary abnormal pressure in the train pipe. The pressure in the brake cylinder 8 reduces towards atmospheric pressure and the pressure in the chamber 18 above the diaphragms, which is now connected to the train pipe, increases and causes the valve 31 eventually to reclose as also will the valve 14 owing to leakage through a restricted port 33 and the abnormal pressure will be dissipated throughout the train pipe. The train pipe pressure is maintained at its normal valve by the feed valve 4, fall due to leakage of train pipe pressure in the chamber 18 causing the valve 31 to open and bring about operation of the valve 4 to supply the train pipe from the main reservoir. The pressure fluid in the chamber 21 may be replaced by a spring.