GB785620A - Improvements relating to fluid pressure braking systems for road vehicles - Google Patents

Abstract

785,620. Fluid-pressure brakes. WESTING- HOUSE BRAKE & SIGNAL CO., Ltd., and SIMMONS, A. W. March 8, 1956 [March 8, 1955], No. 6743/55. Class 103 (1). In a fluid pressure braking system for road vehicles of the kind in which the brakes are operated by compressed air or vacuum under the control of a pedal operated control valve, an additional valve member is connected to the exhaust passage of the control valve to control communication between this passage and external atmosphere, the additional valve being normally open and arranged to be closed by the driver of the vehicle to close the exhaust passage and prevent release of the fluid pressure brakes when, for example, it is desired to increase the power of the hand brake when starting from rest on a steep hill so that both feet of the driver are free to operate the accelerator and clutch pedals of the vehicle. The additional valve member 13 is housed in a casing 1 in which is slidably mounted an adjustable operating rod 2 which may be coupled at its cross-head 4 to the handbrake lever so that when the latter is in its release position the parts of the valve occupy the position illustrated; the valve member 13 being held off the valve seat rib 11 against the action of spring 15 by the reduced end 12 of rod 2 to permit free communication between passage 9 leading to the exhaust port of pedal control valve (not shown) and passage 6 communication with external atmosphere. When hand brake lever is moved to a braking position the rod 2 is moved to withdraw reduced end 12 of rod 2 from engagement with valve member 13 to close communication between passages 9 and 6. Alternatively, the additional valve may be opened and closed by means other than the hand brake lever mounted, for example, on the dashboard of the vehicle.