Abstract: A vacuum brake booster is provided with a front shell coupled to a master cylinder and a rear shell adapted for attachment to a vehicle fire wall. The front shell is provided with a unidirectional accurate portion between radially inner and outer extremes in order to reduce the normal force imparted to the front shell during braking and thereby reduce deflection.

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: A reaction mechanism for use in a vacuum brake booster (10). A lever (86) transfers a reaction force from a first plunge (64) into a second plunger (110) to provide an operator with an indication of the output force being produced in response to an input force. A resilient member (118) urges a first connecting member (116) into engagement with the lever (86). When a predetermined input force is applied, the reaction force overcomes the resilient member (118) and thereafter allows the input force to be directly transmitted through a second connecting member (122) and added to the output force.

Abstract: A method of attaching a master cylinder (12) to a shell (78) of a vacuum brake booster (14) through a sleeve connecting member (62). The sleeve connecting member (62) has internal threads (64) and external threads (66). The master cylinder (12) has an insert 30 which is screwed into the internal theads (64) and the shell (78) of the booster (14) screwed onto the external threads (66) until the internal components (52, 54, 98 etc.) of the master cylinder (12) and vacuum brake booster (14) are in proper alignment. Thereafter, the master cylinder (12) and shell (78) are held stationary and the sleeve (62) is screwed into the shell (78) to lock the master cylinder (12) and shell (78) in a fixed relationship.

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: A reaction mechanism for use in a vacuum brake booster (10). A lever (86) transfers a reaction force from a first plunger (64) into a second plunger (110) to provide an operator with an indication of the output force being produced in response to an input force. A resilient member (118) urges a first connecting member (116) into engagement with the lever (86). When a predetermined input force is applied, the reaction force overcomes the resilient member (118) and thereafter allows the input force to be directly transmitted through a second connecting member (122) and added to the output force.

Abstract: A control valve (81) for a vacuum brake booster (10) having a sleeve member (96) for positioning a poppet valve (92) in a bore (74) of a hub (28) and defining the limits for a continuous flow path (98) between a first chamber (30) and a second chamber (68) within the hub (28).

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 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 actuation assembly (10) and its method of assembly wherein a connecting pin (173) between a movable wall (101) and a torque tube (66) is retained by a keyway (141) in a plunger (140). The pin (173) moves in a slot (69) in the tube (66) in response to a reaction force to provide an input push rod (196) with an indication of the pressurized fluid supplied to a wheel brake (22, 24, 26, and 28).

Abstract: A control device for a vehicle brake system includes a proportioning valve assembly, an inertia sensing valve member and a hill holder valve member in a unitary housing. The inertia sensing valve member is operable in response to vehicle deceleration to control fluid communication via a bypass passage circumventing the proportioning valve assembly.

Abstract: A tandem brake booster (10) having first (24) and second (28) walls that move in opposite directions within a cavity to produce an output force. A lever arrangement (48) attached to the second (28) wall engages a fulcrum (70) to transfer a force produced by movement of the second wall (28) into the first (24) wall. A control mechanism (72) has a cylindrical body (74) with an annular surface (78) that engages the lever arrangement (48). The movement of the cylindrical body (74) as compared to the output member (41) is a function of the ratio of the distance from the fulcrum (70) to end (46) and from the fulcrum (70) to the annular surface (78), and as such, maximum output travel can be achieved without requiring a corresponding input travel.

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 master cylinder includes a housing (22) with a bore (24) for receiving a pair of pistons (36, 38). The housing defines a reservoir (28) with an outer wall (26). The housing also defines at least one outlet passage (62, 66) communicating fluid from the bore (24) to a brake assembly (16). The outlet passage (62, 66) is partially defined by a boss (60) formed integrally with the housing (22) and the boss (60) cooperates substantially with the outer wall (26) to separate the reservoir (28) into a pair of cavities (84, 86).

Abstract: A master cylinder includes a sleeve (31) which defines fixed positions for a pair of seals (30, 32). A pair of pistons (36, 38) cooperate with the seals (30, 32) to form pressure chambers (40, 42) which communicate fluid pressure to brake circuits during braking. A bearing member (44) cooperates with one (36) of the pistons to define an auxiliary pressure chamber (50) and the bearing member (44) is provided with an additional passage (140) for communicating fluid into and out of the auxiliary pressure chamber as well as an end (46) directing movement of the one piston (36).

Abstract: A tandem brake booster (10) having a housing (12) with a cavity therein divided by a first wall (24) and a second wall (28) into first, second and third chambers (20, 26 and 30). The first and second chambers (20, 26) are connected to each other through a control valve (62) and the first and third chambers (20, 30) are connected to each other by a conduit (38). The second wall (28) is connected to the first wall through lever arrangements (100 and 102). When the first chamber (20) is connected to a source of vacuum, air is evacuated from the first, second and third chambers (20, 26 and 30). In response to an input force, the control valve (62) interrupts communication of vacuum to the second chamber (26) and allows air to be communicated to the second chamber (26). With air in chamber (26) and vacuum in the first and third chambers (20 and 30 ) a pressure differential is created across walls (24 and 28).