GB811466A - Improvements in or relating to liquid pressure braking systems - Google Patents

Abstract

811,466. Hydraulic brakes. AUTOMOTIVE PRODUCTS CO. Ltd. June 17, 1957 [June 15, 1956], No. 18646/56. Class 103 (1). [Also in Group XXIX] A liquid pressure braking system includes a plurality of brake-operating motor cylinders 27, 28 and a control valve 24 arranged to supply liquid under pressure to each motor cylinder from a different one of a plurality of liquid pressure accumulators 17 and 18, and a pump 10 arranged to supply liquid under pressure to the accumulators 17 and 18 through a cut-out valve 14, the control valve 24 also controlling a normally open return flow path for liquid from the cut-out valve 14 to the liquid reservoir 11, one of the motor cylinders 27 being so connected to the flow path that pressure built up by closing the flow path at the control valve, operates the cylinder 27. As shown in Fig. 2, the control valve 24 comprises a plunger 73 operated by the pedal 32, the thrust through plunger 73 being transmitted by spring 76 to a cup-shaped member 72, which acts upon the spherically shaped top end of a further plunger 43. Downward movement of plunger 43 has the effect of interrupting flow of liquid from the cut-off valve 14 entering the valve at port 52 and passing away to the reservoir 11 through conrection 49. Simultaneously pressure liquid from reservoir 17 entering at connection 51 is enabled to pass valve surface 45a to port 52 which, as well as being connected to the cut-off valve 14, is in communication with the brake cylinder 27. In a similar manner a second plunger 44 below plunger 43 is also moved down and acts to cut off communication between port 58 connected to the brake cylinder 28 and the line 31 to the reservoir 11. Valve 46a is opened to allow pressure fluid from port 57 and reservoir 18 to pass to the brake cylinder 28. Passages 59, 61 and 60, 62 in the plungers 43 and 44 respectively enable the liquid pressure existing at the ports 52 and 58 to be transmitted past flow-restrictor plugs 65 to act in the spaces below the plungers and cause them to be substantially balanced.