Abstract: In a two-pedal hydraulic braking system for vehicles the pedals are operable independently or simultaneously to apply two sets of brakes and both pedals actuate a common master cylinder to apply fluid under pressure to the brakes. Two normally closed selector valves are operable independently to direct the fluid to either of the sets of brakes when one pedal is operated, and the valves are operable simultaneously to direct the fluid to both sets when the pedals are operated simultaneously. Each valve is urged directly into its closed position by its respective pedal, and each pedal in turn is urged by a return spring into a retracted position in which the valve which it operates is closed.

Abstract: In a disc brake in which the brake applying mechanism is actuated by movement of a first pull rod, the hydraulic actuator which effects movement of the pull rod comprises an assembly of piston and cylinder members of which one is rigidly fixed with respect to a housing and the other is movable relative thereto and acts on the first pull rod. A second pull rod is coupled to the first pull rod and is used for parking or emergency braking.

Abstract: A self-energizing disc brake is operated by an actuator which moves spreading pressure plates angularly in opposite directions to apply rotatable friction discs to radial surfaces in a stationary housing, and the actuator comprises a wedge for separating lugs on the plates, a spring for urging the wedge in a direction to separate the lugs, and a piston working in a cylinder bore for urging the wedge in the opposite direction when the cylinder is pressurized.

Abstract: In a spreading disc brake relative angular movement of the pressure plates to initiate the application of the brake is effected by a fluid pressure actuator acting on a pull-rod through a pivotal thrust coupling so arranged as to confine rocking movement of the pull-rod to a single plane normal to the brake axis.