GB424499A - Improvements in and relating to fluid pressure braking apparatus - Google Patents

Abstract

424,499. Fluid - actuated valves. CADMAN, N. G., and WESTINGHOUSE BRAKE & SAXBY SIGNAL CO., Ltd., 82, York Road, King's Cross, London. Aug. 22, 1933, No. 23359. [Class 135] [See also Group XXXIV] Valves adapted to cut off a vehicle brakeoperating cylinder from the pressure or vacuum source when a predetermined pressure or vacuum is reached or to be rendered inoperative, according to the load conditions of the vehicle comprises in one form, Fig. 1, for a vacuum system, a casing 1 connected to the cylinder and to the driver's valve at 6, 7 respectively and containing a diaphragm 2 connected to the cage of a ball-valve 8. When in applying the brakes, the vacuum in the cylinder and chamber 4 reaches a value sufficient to permit atmospheric pressure in chamber 3 to overcome the spring 10, the valve 8 is seated, but lifts to permit return flow of air in releasing the brakes. The device can be rendered inoperative by connecting passages 6, 7 by cock 9. In another construction, the chamber 3 is closed but can be connected either to atmosphere or to chamber 4 by a cock to render the device operative or inoperative. In a further form, Fig. 4, for compressed air brakes, the pressure in chamber 18 connected to the cylinder, moves the piston 12 against the action of a spring 14 to permit the valve 8 to seat and thus cut off the supply from chamber 19 to chamber 18. The spring may be adjusted to give varying cylinder pressures or the spring casing 13 be caused to abut on the piston to hold the valve off its seat to give the full pressure, by a cam surface 16 on a lever 15.