Allied Corporation

The Bendix Corporation

Alliedsignal Inc.

Robert Bosch Technology Corporation

Lawrence R Myers

Robert F Gaiser

Lloyd G Bach

Larry G Lohraff

Richard T Hendrickson

A tandem brake booster having a housing with a first front chamber separated from a first rear chambers by a first wall and a second front chamber separated from a second rear chamber by a second wall. The first and second front chambers are connected to the first and second rear chambers through passages in a hub which retains a control valve. In a first or ready mode of operation, the first and second front and rear chambers have a substantially identical first fluid pressure while in a second or actuation mode of operation, the control valve responds to an input force to allow a second fluid pressure to be communicated to the first and second rear chambers and create a pressure differential with the first fluid in the first and second front chambers. The pressure differential develops an output force which moves the first and second walls as a function of the input force applied to the control valve. The control valve on termination of the input force returns to the first mode of operation as the second fluid pressure is replaced in the first and second rear chambers by the first fluid pressure. The hub member which retains the control valve has an axial bore. A junction is formed within the axial bore with first and second passages which connect the first front chamber with the first rear chamber to define a first flow path and with third and fourth passages which connect the second front chamber with the second rear chamber to define a second flow path. The first and second flow paths independently allow the second fluid pressure to be simultaneously evacuated from the first and second rear chamber as the control valve returns to the first or ready mode of operation.

Tandem vacuum brake booster

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.

Master cylinder and vacuum brake booster

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). The stationary piston (160) abuts a shoulder (13) of the housing (12) and extends into the second differential piston (140) where it is connected with the second poppet valve (150) controlling fluid flow between the respective inlet (30) and outlet (32). The stationary piston (160) and cage member (60) are biased apart by a plunger spring (205).

Dual deceleration and pressure-sensitive proportioning valve

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.

Reaction mechanism for brake booster

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.

Threaded sleeve member for connecting master cylinder to vacuum booster

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. Upon obtaining an initial level of deceleration, the inertia sensitive ball (40) moves along an initial low slope portion (39) of the surface (17) so that the third valve (35) opens and permits movement of the third piston (105) by the second piston (80) so that higher braking pressures are communicated to the wheel brake cylinder. The proportioning valve assembly (10) eliminates the communication of excessive pressure to a brake assembly during vehicle travel on a low coefficient of friction roadway surface.

Deceleration and pressure sensitive propoptioning valve with low

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.

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).

Control valve

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.

Brake booster

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.

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).

Brake actuation assembly and method of assembly

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.

Combination hill holder and proportioning valve mechanism

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.

Tandem brake booster

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.

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).

Growing community of inventors

South Bend, IN, United States of America

Lawrence R Myers