Abstract: A brake proportioning apparatus which restricts and proportions the application of brake pressure to the wheels of a vehicle under certain conditions is provided. Spring forces and spring rates are utilized to provide a differential brake force to a proportioning valve and provide linear or non-linear programming of fluid pressure.

Abstract: A dual hydraulic brake system incorporating a dual master cylinder for separately pressurizing the front and rear brakes of a vehicle. A device for varying the proportion of brake pressure applied to the front and rear brakes of a vehicle is positioned between the master cylinder and the front and rear brakes. The device includes a differential area piston for decreasing the proportion of brake pressure delivered to the rear brakes above a first preselected inlet pressure. Positioned within the differential area piston is a second valve assembly which is actuated in response to attainment of a second preselected brake pressure and which blends back the pressure in the rear brake system until it attains the pressure in the front brake system.

Abstract: A differential pressure warning switch comprising a housing defining a chamber, hydraulic conduits communicating the master cylinder and front and rear fluid brake actuators of an associated vehicular brake system with the chamber, a shuttle piston movable within the chamber between opposed translated positions in response to differential pressure conditions existing between the front and rear brakes of the vehicle, and a pair of pressur responsive flexible diaphragm elements arranged adjacent the opposite ends of the shuttle piston and adapted to effect shuttle movement of the piston in response to predetermined differential pressur conditions in the brake system, whereby to complete an electrical circuit to an associated warning lamp or the like.

Abstract: A dual hydraulic brake system incorporating a dual master cylinder for separately pressurizing the front and rear brakes of a vehicle. A pressure limiting device is positioned in the brake system for the front wheels which have disc-type brakes. The device prevents the front brakes from being energized until the rear drum-type brakes are functioning and then proportions the pressure applied to the front brakes. Also, an apparatus for providing an indication to the operator of failure of either the front or rear brakes, which apparatus will automatically reset itself upon correction of the failure, is positioned adjacent the pressure limiting device and is responsive to fluid pressure in both systems.

Abstract: A device for varying the proportion of brake pressure delivered to the front and rear brakes of a vehicle, and including a differential area piston for decreasing the proportion delivered to the rear brakes between the first and second inlet pressures, and an additional valve assembly actuatable in response to a predetermined pressure differential between the fluid pressure delivered to the piston and the fluid pressure delivered thereby to the rear brakes so as to establish a decreasing pressure differential between the pressure delivered to the front and rear brakes.