Abstract: The combination accumulator and variable volume sump (50) comprises a housing (52) having therein a stepped bore (56). An H-shaped piston and a U-shaped piston (60, 80) are diaposed within the stepped bore (56), the first piston comprising an accumulator piston (60) and defining with the housing (52) and stepped bore (56) a first chamber (70) containing therein pressurized medium. The second piston (80) defines with the housing (52) and stepped bore (56) a second chamber (90) containing therein pressurized fluid. Open ends of the U-shaped pistons (60, 80) are received one within another, and a spring (95) is disposed between interior openings (62, 82) of pistons (60, 80) to bias them apart. The housing (52) has a pair of openings (54, 59) for communicating pressurized fluid, one opening (54) communicating with the second chamber (90) and the other opening (59) communicating with the stepped bore (56) in order to communicate pressurized fluid to the first piston (60).

Abstract: The invention is a hydraulic failure compensating switch which incorporates a differential pressure valve which responds to a hydraulic failure in one of a pair of vehicle braking circuits and altering the pressure reducing function of the braking system proportioning valve(s) in response thereto to increase braking torque at the vehicle's rear wheels.

Abstract: A dual proportioning valve assembly (10) for a vehicle braking system comprises a housing (12) having a pair of inlets (29, 30) and outlets (31, 32), a bore (25) within the housing (12) containing a pair of oppositely disposed differential pistons (40, 140) biased apart by a main spring (200). The first and second differential pistons (40, 140) have associated first and second poppet valves (50, 150) which control fluid flow between the respective inlet and outlet. A cage member (60) extends within the first differential piston (40) and is connected with the first poppet valve (50), the cage member (60) extending longitudinally within the bore (25) and having an interior chamber (70) with an inertia-sensing mass (80) therein. The inertia-sensing mass (80) engages a third poppet valve (94) which controls fluid flow between the interior chamber (70) and a variable volume chamber (100) defined by the cage member (60) and a stationary piston ( 160) which engages the cage member (60).

Abstract: The invention is an improved anti-lock braking system in which the conventional brake switch operable in response to movement of the brake pedal is utilized by the electronic control of the anti-lock brake system to generate a control signal. The isolation and build valves of one hydraulic circuit are energized in response to the control signal to connect a wheel cylinder to the booster of the braking system.

Abstract: A proportioning valve assembly (10) in a housing (12) is pressure responsive to control the flow of fluid to a wheel brake cylinder. The proportioning valve (20) is connected to a channel (31) opening into a reservoir or fluid-containing chamber (13), a second valve (34) being disposed in the channel (31) and engaging at one end an inertia sensitive ball (40) located on a variable slope surface (17), and engaging a third valve (35) at the other end. The proportioning valve (20) includes a second piston (80) having a reduced diameter end (82) engaging a third piston (105) of enlarged diameter disposed in a portion of the channel (31), the channel (31) communicating by an opening (90) with the fluid-containing chamber (13). During initial brake application by the operator, the third valve (35) remains closed so that the third piston (105) does not move and prevents further movement of the second piston (80), thereby preventing higher braking pressure from being communicated to the wheel brake cylinder.

Abstract: The brake booster (12) includes a housing (30) with at least one piston (38) disposed in a bore (32) to separate a pressure chamber (42) from a work chamber (76). The piston (38) engages a valve housing (79) containing therein a valve assembly (80) and the valve assembly (80) is connected to an input assembly (72) abutting the other end of the valve housing (79). The piston (38) is disposed within an extension (81) of the valve housing (79) and a seal (87) and spring (89) are disposed between the piston (38) and valve housing (79) so as to enhance initial movement of the piston (38) and provide a quick take-up and fast fill that compensates for fluid losses in the system while maintaining a reduced stroke for brake pedal travel.

Abstract: A brake booster includes a valve member which is operable to communicate fluid pressure to a pressure chamber for generating a power assist during braking. The brake booster provides an auxiliary chamber to trap fluid pressure leakage past the valve member. An input member is operable during braking to initially vent the auxiliary chamber and thereafter to control operation of the valve member.

Abstract: A brake control device (20) is disposed between a brake pedal (12) and a clutch pedal (10) to retain the brake pedal (12) in an applied position when the clutch pedal (10) is depressed and the vehicle is facing downhill on an incline and in reverse gear, so that the vehicle operator may remove his foot from the brake pedal (12). A control circuit (110) includes a backup light switch (114) and attitude switch (116) for operating a solenoid actuator (120) that applies a locking ball (28) of the brake control device (20). A brake control device (320) may be operated by a solenoid actuator (325) controlled by an electronic control unit (340) so that the brake pedal (12) is retained in an applied position whenever the vehicle is stationary and the clutch pedal (10) depressed.

Abstract: A disc brake assembly (10) includes a caliper (22) movably supported by a torque member (36). The caliper (22) and torque member (36) each have lateral recesses (44, 46, 48, 50) defining axially extending apertures (52, 54) between the caliper (22) and torque member (36), with a pair of wedge-shaped members (66, 68) disposed in each aperture to maintain the caliper in radial and circumferential position relative to the torque member while allowing lateral movement therebetween. The wedge-shaped members (66, 68) are biased inwardly by an improved dual purpose spring member (72) which traverses a portion of the exterior perimeter of the torque member (36) and engages the ends of the respective pins.

Abstract: A brake booster (16) includes a pair of pistons (50, 56) and a valve assembly (74) operable to communicate fluid pressure to the pair of pistons (50, 56). An input assembly (90) moves in response to an input force to control the operation of the valve assembly (74). Movement of the valve assembly (74) allows fluid to be supplied to working chambers (52, 58). Resilient means (133, 135) acts on and holds pins (130, 132) against the pistons (50, 56). When the fluid pressure in the working chambers (52, 58) acting on the pins (130, 132) is sufficient to overcome the resilient means (133, 135) an increase in the fluid pressure in chamber (52, 58) moves the pins (130, 132) into engagement with the input assembly (90) to oppose movement of the input assembly (90) since a desired brake force has been generated.

Abstract: A brake system includes a brake booster coupled to a front wheel brake cylinder. The brake booster substantially defines a pair of rear wheel brake cylinders separate from the front wheel brake cylinder so that a pair of diaphragms are separated during braking to generate a power assist for the front and rear brake cylinders. A control valve cooperates with the brake booster to alter the power assist for the rear brake cylinders in response to a signal from an electronic control unit.

Abstract: A fluid pressurizing device 10 having a master cylinder 12 with a cylindrical projection 52 that extends through the housing of a brake booster 14. The housing of the brake booster 14 has a front shell 56 located on a shoulder 54 of the cylindrical projection 52 and a rear shell 140 located against a shoulder 150. A nut carried by the cylindrical projection 52 engages the rear shell 140 to compress a bead 111 of a diaphragm 110 against a shoulder 57 on the front shell 56. A sleeve 80 connected to a hub member 70 retains a bead 108 of diaphragm 110 and bead 90 of a diaphragm 92 connected to the cylindrical projection 52. In response to an input force, a valve assembly 136 controls the development of a pressure differential across the diaphragms 92 and 110. The pressure differential acts on and moves the diaphragms 92 and 110 toward the first shell 56.

Abstract: A master cylinder includes a housing (30) with a stepped bore (32) receiving a sleeve assembly (50). A pair of pistons (80, 82) are disposed within the stepped bore (32) and one (82) of the pair of pistons defines portions of compensation passages between a reservoir (37) and a pair of pressure chambers (88, 90). The one piston (82) is movable to simultaneously control communication through the compensation passages.

Abstract: A brake booster (16) includes a housing (26) with a plurality of parallel bores (38, 40, 42). A first piston (50) is disposed in the bore (38), a second piston (56) is disposed in the bore (40) and a valve assembly (74) is disposed in the bore (42) to control communication of fluid pressure to a pair of working chambers (52, 58) within the bores (38, 40). A pair of connecting pins (130, 132) cooperate with a plunger (100) to transmit a reaction force to a vehicle operator.

Abstract: A fluid pressure proportioning valve (48), particularly of the type which is used in the hydraulic braking systems of automotive vehicles, includes a plug member (28) movably carrying a piston member (50). The piston member (50) defines a through bore (88) communicating pressurized fluid to an outlet on the plug member (28). The piston member also carries a valve member (116) opening and closing the through bore (88) in response to reciprocation of the piston member (50). A lip seal (62), spring seat (100), and a coil spring (110) are carried by the piston member (50). The plug member (28), piston member (50), valve member (116), lip seal (62), spring seat 100, and coil spring 110, comprise a unitary subassembly (142) which may be assembled with a housing providing a bore for receiving the coil spring (110) and lip seal (62) and providing an inlet communicating pressurized fluid from a master cylinder (10).

Abstract: A hydraulic brake booster is disclosed which includes an integral accumulator to provide a fluid pressure source for emergency failsafe braking. The accumulator includes a bore defined within the booster housing, and a piston slidably mounted in the bore which divides the latter into a pair of fluid compartments between opposite ends of the piston and corresponding ends of the bore. One of the compartments is communicated to the booster inlet port so that the compartment is charged with fluid pressure whenever the pressure level at the inlet port is above some predetermined low value. In one embodiment of the invention, the other compartment is communicated to the fluid pressure reservoir, and a relief valve is carried within the piston which controls flow of fluid between the two compartments.

Abstract: A hydraulic brake booster is disclosed which includes an integral accumulator to provide fluid pressure source for emergency failsafe braking. The accumulator includes a bore defined within the booster housing, and a piston slidably mounted in the bore which divides the latter into a pair of fluid compartments between opposite ends of the piston and corresponding ends of the bore. One of the compartments is communicated to the booster inlet port so that the compartment is charged with fluid pressure whenever the pressure level at the inlet port is above some predetermined low value. In one embodiment of the invention, the other compartment is communicated to the fluid pressure reservoir, and a relief valve is carried within the piston which controls flow of fluid between the two compartments.

Abstract: An accumulator for use in a brake booster having a housing with a piston located in a bore. The piston has a plug attached thereto. The piston moves in response to a predetermined thermal expansion of a fluid in the accumulator. A predetermined movement shears the plug from the piston to prevent damage to the housing by venting the bore to a reservoir.

Abstract: A hydraulic brake booster is disclosed which is normally actuated by a primary pressure source, but which may be actuated by a secondary pressure source during failure of the primary pressure source. The booster includes a spool valve which controls communication between the primary pressure source and the booster pressure chamber. The spool valve is actuated by a control pressure which is generated by the vehicle operator when a brake application is effected. The control pressure shifts the spool valve to cause the latter to communicate fluid pressure from the primary pressure source into the pressure chamber. A pressure differential responsive piston is responsive to a pressure differential between the control pressure and the pressure communicated into the booster pressure chamber.

Abstract: A hydraulic brake booster is disclosed for use in a vehicle hydraulic braking system. The booster provides a spool valve having spaced lands and grooves cooperating with corresponding lands and grooves on the booster housing to control communication between an inlet port, an outlet port, an exhaust port, and the booster pressure chamber. The spool valve has an internal passage which communicates the booster pressure chamber to one of the aforementioned ports depending upon the position of the spool valve. A check valve is provided in a branch passage communicating with the groove communicated with the booster inlet port so that the pressure level in the pressure chamber never exceeds the pressure level at the inlet regardless of the position of the spool valve. This feature enhances spool stability.