GB366602A - Improvements relating to fluid pressure braking apparatus - Google Patents

Abstract

366,602. Fluid - pressure brakes. TOMLINSON, A. V., 65, Victoria Street, London.-(Westinghouse Brake Co. of Australasia, Ltd. ; George Street, Concord West, New South Wales, Australia.) Nov. 8, 1930, No. 33696. [Class 103 (i).] In fluid-pressure brake apparatus of the straight air type comprising a train pipe extending throughout a train of vehicles each having one or more driver's valves, communication between any driver's valve and the train pipe leading directly to the brake cylinders is established through a transfer valve which, when the driver's valve is in a position at which the operating handle can be removed, cuts off communication between the driver's brake valve and the brake cylinders. A driver's valve in the inoperative position when the handle can be removed, supplies fluid at full reservoir pressure to the transfer valve. The driver's valves 7, 8 at each end of a vehicle are in inoperative position and supply fluid from the reservoir 5 through pipes 25 .. 28 to the outer sides of pistons 14, 15 of the transfer valve 12, which are thus held in central position by spring abutments 31, 32, so that both driver's valves are cut off by a slide valve 19 from the connection 22 to the train pipe 9 and brake cylinders 6. The operating handle is placed on the driver's valve, for instance valve 7, from which it is desired to effect the control of the braking and the valve is moved to release position when the pipe 25 and the outer side of the piston 14 will be vented to atmosphere and the pistons 14, 15 will move to connect the passages 22, 25 by means of the cavity 34 in the slide valve 19. The brake can now be controlled through passages 25, 22. The pressure transmitted to the piston 14 through passage 27 on brake application is balanced by full reservoir pressure supplied to the other side of the piston through passage 26 until full reservoir pressure is supplied to the brakes and the passage 27 which with the pressure of the compressed spring 33 can overcome the pressure on the other side of the piston so that the pistons are not displaced until full reservoir pressure is supplied to the brakes. Leakage grooves 35 balance the pressure on the pistons in central position. In a modified form of transfer valve for vehicles having only a single driver's valve each, one piston is used which holds the valve in inoperative position against spring pressure.