GB1122701A - Master cylinders for hydraulic braking systems - Google Patents

Abstract

1,122,701. Hydraulic brakes; transmitting mechanism for brakes. C. C. FAY. 8 Sept., 1965, No. 38411/65. Headings F2E and F2F] In an hydraulic fluid pressure braking system having two independent fluid circuits supplied by a pair of master cylinders 12, 15, one for each of the fluid circuits, each master cylinder having a piston 32 and 33 respectively adapted to be moved simultaneously by means of a rocking beam cross-member 75 coacting between the pistons to transmit an axial force supplied to a piston actuator 64 by means of a link member 19 actuated by the brake pedal. In the event of failure of one of the fluid circuits, provision is made for one of a pair of shoulders 71, 72 on the piston actuator to contact an oppositely facing shoulder 58, 58a on the appropriate piston to differentially drive the piston in the line not subject to the leakage independently of the rocking beam cross-member 75. Provision is made by bleeding off air trapped in each master cylinder by means of a bore in the boss communicating with the master cylinder and a valve pin coacting with the bore to selectively open and close the bore on the removal of the trapped gases. The bleed pin may include a longitudinal keyway slot intermediate the extremity of the pin for allowing the air to pass from the bore to the reservoir. An alternative embodiment is disclosed in the Specification (Fig. 12, not shown), wherein the master cylinders shown in Figs. 2 and 3 are replaced by master cylinders of the kind having a reservoir replenishing opening at the forward end of the master cylinder and an outlet connection provided within the working space of the cylinder.