GB1084104A - - Google Patents

Abstract

1,084,104. Fluid-pressure brakes; valves. REGIE NATIONALE DES USINES RENAULT. Nov. 3, 1964 [Nov. 9, 1963], No. 44857/64. Headings F2F and F2V. Operation of a pressure-limiting valve, adapted to cut off an hydraulic pressure supply source, e.g. a master cylinder, from rear brake cylinders of a vehicle when the pressure supplied by the source and acting on a piston carrying a valve closure member is above a predetermined value, is damped by the provision of a damping chamber on the side of the piston opposite that which is subjected to source pressure, and means for retarding the flow of fluid displaced from the damping chamber by the piston. In one embodiment, Fig. 1, the valve body 1, which contains the piston 3, rigidly connected with valve closure member 2 adapted to close a passage between inlet 6 and outlets 11, is extended to provide a damping chamber 12 which communicates via a restricted passage 14 with a reservoir 13 formed by a rubber bladder 16 fixed to the body 1 by a clamp 17. When supply pressure acting on piston 3 is sufficient to overcome a spring 4, closure member 2 moves to shut off communication between inlet 6 and outlets 11, the movement being damped by the fluid in chamber 12 being forced by piston 3 through the passage 14 into the bladder 16. The fluid in chamber 12 and bladder 16 is preferably brake fluid. The embodiment of Fig. 2 (not shown) is similar except that the bladder is replaced by a further extension of the body (1) to provide a further cylinder bore (13) in which slides a piston (18) which maintains the damping fluid under light pressure through the action of a spring (19). A stronger spring (19) may be used, in which case it could be made adjustable either manually or automatically in accordance with vehicle load. The spring (4) could then be omitted.