GB768536A - Fluid pressure operable vehicle brake control apparatus - Google Patents

Abstract

768,536. Anti-skid brakes. WESTING- HOUSE AIR BRAKE CO. April 27, 1955 [April 28, 1954], No. 12141/55. Class 103 (1). In an anti-wheel slide brake control system for aircraft of the kind described in Specification 674,506, it may occur that with repeated braking cycles, the pressure in the supply reservoir might be reduced below that necessary to provide a proper application of the brakes and to avoid this possibility a safety interlock device 7 is provided which operates to prevent venting of the brake cylinder under these conditions. On operation of the inertia control device 5 to tilt lever 27 to open valve 47, the space below piston 31 is exhausted and the consequent pressure differential across restricted passage 35 in the piston causes the valve member 29 to be moved down, so that pressure from the brake cylinder may be released by way of pipe 12, passage 38, pipe 9 and exhaust port 65 in the device 7. If the pressure in the reservoir 2 should fall below a certain value, such pressure acting in space 60 at the lower end of device 7 allows the spring 68 to force down the piston 61, thus cutting off the escape port 65 and preventing automatic venting of the brake cylinder until the supply pressure has been restored. The device 7 may be modified so as to be snap-acting. In the arrangement shown in Fig. 4, the pipe to the brake cylinder 3 is connected through the safety interlock device 98 comprising a slide valve piston which, on drop of reservoir pressure acting in chamber 104, is moved downwardly by spring 106 so as to cut off pipe 12 from pipe 99, the latter then being connected direct to paper 8 from the control valve 4.