Abstract: A control apparatus for a brake system having a housing with a first bore for retaining a spool valve and a second bore for retaining a selector valve. A cap separates the first bore into a first chamber and a second chamber. The first chamber has an inlet port connected to a source of fluid under pressure, a gear port for connected the source of fluid under pressure to a hydraulically operated device, a relief port connected to a reservoir and an outlet passage connected to a selector valve which communicates pressurized fluid through an outlet port to a brake booster. The second chamber is connected to the reservoir and the second bore. The a spool valve has a peripheral surface with first and second grooves separated by lands and an internal operational passage connecting the second groove to the outlet passage.

Abstract: A master cylinder and pneumatic brake booster having hydraulic reaction means. The hydraulic reaction means which is mounted to slide within a main piston (12) in the master cylinder includes a central shut-off piston (4), a stepped and hollow reaction piston (5) and a ratio-change piston (6). First (71), second (72) and third (73) springs are associated with said hydraulic reaction means such that a push rod (3) receives only a portion of a reaction force is an actuation force is applied rapidly which is proportional to a difference between an internal cross section of the reaction piston (5) and an external cross section of the reaction piston (5).

Abstract: A tandem hydraulic master cylinder having body (1) pierced with a bore having first (2a) and second (2b) inlets for receiving hydraulic fluid at low pressure. A primary piston (3) and a secondary piston (4) respectively slide in first (S1) and second (S2) length sections of the bore of body (1). A primary pressure chamber (5) is located in the bore between the primary piston (3) and the secondary piston (4) and a secondary chamber (6) is located between the secondary piston a bottom of the bore. First and second upstream and downstream sealing cups (91a,91b) and 92a,92b) respective seal the bore and the primary chamber (5) and the secondary chamber (6). The primary chamber (5) has a first re-supply duct (21) and a first outlet orifice (41) and the secondary chamber (6) has a second re-supply duct (22) and a second outlet orifice (42) for receiving and communicating hydraulic fluid.

Abstract: A method of setting a gap between a poppet member and a seat in a check valve by sensing the position of an cylindrical projection extending from an end cap while sonically welding the end cap to a housing

Abstract: A drum brake for use in a brake system (10) having first (14) and second (16) shoes retained on a backing plate (20). The first brake shoe (14) has a first end (22) connected to an actuator (12) and a second end (26) connected to an anchor arrangement (24) and the second brake shoe (16) has a first end (36) connected to the actuator (12) and a second end (38) connected to the anchor arrangement (24) The actuator (12) responds to an input signal during a brake application by moving the first (14) and second (16) brake shoes into engagement with a drum (18). The anchor arrangement (24) includes a load sensor (64) for measuring a torque generated between the first (14) and second (16) brake shoes and the drum (18). The anchor arrangement (24) has a bracket (44) with a base (46) having first (48) and second (50) side walls which are secured to the backing plate (20). The first side wall (48) has a first central opening (56) therein while the second side wall (50) has a second central opening (58) therein.

Abstract: A pneumatic servo for assisting with braking having a casing (10) with a cylinder (38) and a cover (40) with an axis of symmetry (X-X'). A wall structure (12) divides the interior of the casing into a front chamber (14) and a rear chamber (16). The movable wall structure (12) has a rear tubular part (22) which slides in a leaktight fashion in the cover (40) and retains a three-way valve (26) which is actuated by a control rod (30). The front chamber (14) is permanently connected to a source of vacuum while the rear chamber (16) is connected selectively to the front chamber (14) and a source of pressure through the three-way valve (26). The cylinder (38) and cover (40) being made from two identical half-shells (38,40).

Abstract: A secondary source of braking for large hydraulically braked vehicles utilizing the available power source (38) provided by typically available anti-skid and traction control braking systems. The invention improves the time response of a secondary braking traction control system by utilizing stored fluid in the low pressure anti-skid braking system accumulators (34) to provide for faster build of pressure by the pump motor (38). Fluid is stored and utilized based on vehicle behavior and operational states and is based upon the principal the traction control, anti-skid braking and secondary braking requirements are generally mutually exclusive. This allows for a decreased response time of the secondary braking system and also provides for improved initial cycle response of typical traction control events that utilize the system configuration.

Abstract: A control apparatus (12) in a brake system (10) has a housing (20) with an inlet port (26), a gear port (32), a relief port (38), and an outlet port (42). A piston (44) located in a first bore (22) has a first peripheral surface (50) with first (52) and second (54) grooves separated by a land (56) and a second bore (60) respectively connected to the first (52) and second (54) grooves by first (62) and second (64) radial passages. A spool (68) which has a peripheral surface (74) with a control groove (76) is connected to a third bore (88) therein by a cross bore or passage (86) and retained in the second bore (60) by a snap ring (96). An input rod (92) which is located in the third bore (88) has a shoulder (94) which engages the spool (68) while an end cap (98) that is connected to the housing (20) retains the piston (44), spool (68) and input rod (92) in the housing (20).

Abstract: A drum-in-hat brake assembly (10) having first (12) and second (14) brake shoes retained on a backing plate (16) by first (18) and second (20) pins connected to the backing plate (16). The first (12) and second (14) brake shoes are aligned on the backing plate (16) by an anchor post (40) and connected to a reverse actuator (26). The reverse actuator (26) receives an input force to respectively move first (42) and second (44) friction pads associated with the first (12) and second (14) brake shoes into engagement with a drum (46) to effect a brake application. The reverse actuator (26) includes a first lever (52) and a second lever (54), each of which have a flat plate (60,76) that extends through an opening (62) in the backing plate (16). A resilient member (90) located in the opening (62) maintains the flat plates (60,76) in a same perpendicular plane with respect to the backing plate (16).

Abstract: A boosted braking system for a motor vehicle having a master cylinder (200) and a pneumatic booster (100). The master cylinder (200) causes an increase in pressure of brake fluid supplied to at least one wheel brake (300). The pneumatic booster (100) is controlled by the application of an input force (F2) to a control rod (26) to actuate the master cylinder (200). A main hydraulic piston (30) of the master cylinder (200) has a hollow cylinder (32) in which a reaction piston (34) slides in a leaktight and axial direction. The reaction piston (34) receives at least the input force (F2). An elastic member (46) located between the reaction piston (34) and hollow cylinder (32) exerts an elastic force for urging the reaction piston (34) toward the master cylinder (200). The reaction piston (34) delimits within the cylinder a reaction chamber (36) which is isolated from the interior volume (V) of the master cylinder (200).

Abstract: A master cylinder having a first housing with an axial bore therein which is connected to a second housing of a reservoir. The axial bore has a first replenishing port surrounded by a first boss and a second replenishing port surrounded by a second boss. A first radial bore in the first boss extends from the first replenishing port while a second radial bore in the second boss extends from the second replenishing port. First and second spigots which extends from the second housing are respectively located in the first and second radial bores to provide first and second flow communication paths from the reservoir to the axial bore.

Abstract: A tandem master cylinder with a bore (1a) for retaining primary (3) and secondary (4) pistons. The secondary piston (4) has a bearing surface (40) for retaining a ring (10) slideably located between a first spring (8) and a seal (4b). The ring (10) pushes the seal (4b) back against a shoulder (41) on the secondary piston (4) in order to transmit a compressive force to seal (4b). The intensity of the compressive force varies with the force exerted on and transmitted by spring (8). The secondary piston (4) has a stop piece (42) for limiting the sliding of the ring (10) in the direction of the second seal (4b) in the bore (1a) of the master cylinder resulting in better sliding of seal (4b) within bore (1a). The functional relationship between the stop piece (42) and second seal (4b) provided for a substantially total reduction of any pressure difference between the pressurized fluid supplied to a primary and secondary circuits supplied by the master cylinder.

Abstract: A master cylinder (12) for use in a brake system. The master cylinder (14) has a housing (22) with a bore (20) therein connected by a radial port (28) and an axial port with a reservoir (32) and to the brake system through first (34) and second (36) outlet ports. First (42) and second (44) pistons located in the bore (20) are separated by a first resilient means (46) to define a first chamber (50) while the second piston (44) is separated from the bottom (21) of the bore (20) by a second resilient means (48) to define a second chamber (52). The first and second resilient means (46,48) each include a first spring (90) which is caged between a first retainer (94) and a second retainer (96) by a linkage member (98) and a second spring (92). The linkage member (98) has a head (126) which engages the first retainer (94) and an end (128) which engages the second retainer (96) to hold the first spring (90) between the first (94) and second (96) retainers.