Abstract: A servomotor having a partition for separating a first chamber from a second chamber. The partition has a hub with passages therein connecting the first and second chambers with each other and to the atmosphere. The partition has a plurality of concentric annular ribs and radial ribs to strengthen a radial disc that extends from the hub. A valve carried in said hub controls the communication of turbulent free air to the second chamber to create a pressure differential for moving the partition and developing an output force in response to an operator input. This same pressure differential acts on a diaphragm connected to the radial disc to seal a plurality of openings in the radial disc to assure that the pressure differential is not reduced by leakage through the openings.

Abstract: The master cylinder (10) comprises a front or first housing part (12) which is generally U-shaped and a second or rear housing part (14) which is also generally U-shaped, the second housing part (14) being received within an end opening of the first housing part (12). The second housing part (14) has an end opening (16) opposite the first housing part (12) through which a first piston (18) is received. The first piston (18) and a second piston (22) are biased by respective resilient mechanisms (20, 24) disposed within a bore (26) defined by the parts (12, 14). Captured between the first and second housing parts (12, 14) are first and second interface members (80, 90) which have seals insert molded thereon. The first and second housing parts (12, 14) are held together by self-threading screws (100) such that a predetermined clamp load is imposed upon the interface members (80, 90). The master cylinder (10) has outlets (34, 36) all of which are oriented longitudinally toward the fron of the master cylinder.

Abstract: A proportioning valve (40) is disposed within a stepped bore (13) of a master cylinder (10). The proportioning valve (40) defines with the stepped bore (13) a primary pressure receiving chamber (26) and a secondary pressure receiving chamber (28). The proportioning valve (40) includes a two-part piston (58) which includes a primary piston part (52) and a secondary piston part (54) coupled together by a lost motion coupling (53, 55). The piston parts (52, 54) are biased apart by a spring (78), and a sleeve (43) is disposed about the two-part piston (50). Seals (46, 47, 69) are disposed about the primary piston part (52), sleeve (43) and secondary piston part (54) to define an intermediate vented chamber (90), wherein a vent (19) communicates with a reservoir.

Abstract: The unitary poppet valve assembly (50) comprises an annular retainer (52) having an open end (54) and an opposite end (55) with a small diameter opening (56) therein. The annular retainer (52) has a plurality of fingers (58) extending laterally therefrom for engagement with the body (12) of a proportioning valve assembly (10). A poppet (70) comprises a poppet head (72) extending radially outwardly from a longitudinal shaft (74), and an oppositely disposed abutment (76). The shaft (74) extends slidably through the small diameter opening (56) in the annual retainer (52), the abutment (76) engaging the retainer (52) adjacent the opening (56). A spring (60) is disposed between a corner or shoulder (57) of the annular retainer (52) and a shoulder (77) defined between the poppet head (72) and poppet shaft (74). The poppet (70) includes a central through opening (78) extending through the abutment (76) and to the head (72), wherein the opening (78) communicates with a lateral through opening (80) of the shaft (74).

Abstract: A two stage relief valve for a quick-fill master cylinder (10). The two stage relief valve (54) has a ball (88) that is biased against a first seat (82) to control the flow of fluid from a quick-fill chamber (30) and a unitary structure (55, 74) which is biased against a second seat (70) to further control the flow of fluid from the quick-fill chamber (30). A first predetermined fluid pressure moves the ball (88) off the first seat (82) to allow fluid to escape from the quick-fill chamber (30). A second predetermined fluid pressure moves the unitary structure (55, 74) to allow additional fluid to escape and thereby limit the fluid pressure development in the quick-fill chamber (50).

Abstract: The proportioning valve assembly (40, 140) may be screwed into a complementary-shaped opening in a master cylinder (10). The valve assembly (40, 140) includes a differential area piston (50, 150) biased by a spring (70, 170) toward the outlet (21, 121) which communicates with the rear brakes. The master cylinder (10) includes a pair of passageways (16, 18) which communicate primary fluid pressure and secondary fluid pressure directly to the differential area piston (50, 150) of the proportioning valve assembly (40, 140) to displace the piston (50, 150) to a balanced position. If there is a failure of pressure in the primary brake circuit, the proportioning valve assembly (40, 140) actuates the differential area piston (50, 150) to permit fluid flow to bypass the piston (50, 150) and be communicated directly to the rear brakes of the vehicle.

Abstract: A master cylinder (10, 210, 310, 410) includes a housing bore (14) having at one end (16) a bearing member (18) attached thereto and retaining a sleeve member (20) within the bore (14). One piston (30, 230, 530) has at one end (32, 232) thereof a fast fill mechanism (150, 350, 450). The fast fill mechanism (150, 350, 450) includes a seal support (130, 330, 430), fast fill seal (160, 360, 460), a ramp (132, 332, 432) on the fast fill seal support (130, 330, 430), and a ramp (125, 325, 425, 525) at the one end (32, 232) of the piston. The ramp (125, 325, 425, 525) at the one end (32, 232) of the one piston (30, 230, 530) may be disposed within the piston (230, 530, 441) or on a flange support (120) mounted on the one piston (30).

Abstract: The unitary poppet valve assembly (50) comprises an annular retainer (52) having an open end (54) and an opposite end (55) with a small diameter opening (56) therein. The annular retainer (52) has a plurality of fingers (58) extending laterally therefrom for engagement with the body (12) of a proportioning valve assembly (10). A poppet (70) comprises a poppet head (72) extending radially outwardly from a longitudinal shaft (74), and an oppositely disposed abutment (76). The shaft (74) extends slidably through the small diameter opening (56) in the annual retainer (52), the abutment (76) engaging the retainer (52) adjacent the opening (56). A spring (60) is disposed between a corner or shoulder (57) of the annular retainer (52) and a shoulder (77) defined between the poppet head (72) and poppet shaft (74). The poppet (70) includes a central through opening (78) extending through the abutment (76) and to the head (72), wherein the opening (78) communicates with a lateral through opening (80) of the shaft (74).

Abstract: The master cylinder (10) comprises a housing (12) having a longitudinal bore (14), an end (24) enclosed by a bearing member (18) which retains a sleeve member (20) within the bore (14), a reservoir (70) mounted on the housing (12) and a pair of pistons (30, 40) slidably received within the bore (14), one piston (30) extending through the end (24) of the sleeve member (20). The one piston (30) has a reduced diameter end (32) which provides seating for a fast fill valving mechanism (110). The fast fill valving mechanism (110) comprises a fast fill seal (120) having a flexible arm (122) engaging an interior surface of the sleeve member (20) and the sleeve member (20) having longitudinal grooves (22) adjacent the arm (122), a fast fill spring member (140) trapped between the fast fill seal (120) and a land member (130), the land member (130) having pockets (132) covered by the fast fill spring member (140) and the pockets (132) communicating with passages (133) in the land member (130).

Abstract: A master cylinder (10) having a sleeve (24) for positioning first (22) and second (30) seal members within a bore (14) of the housing (12). The first (22) and second (30) members each have a primary seal (52), a retainer (58) and secondary seals (54 or 55). The primary seals (52) have a base member (60), a peripheral ring (64) and a flexible bellows section (66). The retainers (56) have a groove (70) for holding the base member (60), radial slots (74, 74') connect to a source of fluid and either a rib (100) or projection (94) for positioning the secondary seals (54 or 56). First (38) and second (40) pistons which engage the first (30) and second (22) seal members, have communication passages (80, 82) through which the radial slots (74, 74') (75, 75' ) are connected to first (46) and second (42) chamber.

Abstract: A reservoir (20) for a master cylinder (16) has a body (22) with an end member (82) attached thereto by tangs (92, 92' . . . 92.sup.N) that engage a surface (69) on a flange (70). A shoulder (86) concentric to peripheral lip (84) on the end member (82) retains a seal (96). A projection (90) that extends from the end member (82) acts as a stop to assure that a pin (52) on a lever (54) that carries a magnet (60) remains attached to arms (44) extending from the body (22). While motion may move the fluid in compartments (34 and 36) toward flange 70, shoulder (86) acts a first barrier and seal (96) acts as a second barrier to prevent fluid from leaking through the mechanically formed joint. If fluid is lost from the compartments (34 and 36) a float (58) tracks the fluid level and moves magnet (60) toward sensor (64) to inform an operator of the change in fluid level.

Abstract: A master cylinder includes a housing with a pair of pistons movable therein to develop fluid pressure in a pair of pressure chambers. One of the pistons carries a seal assembly in order to provide a fast-fill feature. The seal assembly engages a large diameter section during initial braking and separates therefrom after a predetermined fluid pressure level is reached so that the one piston moves relative to a small diameter section to continue fluid pressure buildup during braking.

Abstract: A fast-fill master cylinder (14) includes a housing (26) defining a bore (38) therein having a portion (y) thereof of substantially constant diameter. A primary piston (54) is movably received in the bore portion (y) and a secondary piston (56) is movably received in the remainder of the bore (38). The secondary piston (56) cooperates with the housing (26) to define a secondary variable-volume chamber (62). The primary piston (54) cooperates with the housing (26) and with the secondary piston (56) to define aprimary variable-volume chamber (58). The primary piston also cooperates with the housing to define a constant-volume recess (84) circumscribing the piston (54). An annular partition member (94) circumscribes the piston member (54) within the recess (84) to divide the recess (84) into a pair of variable-volume compartments (108, 110). A bore 120 communicates the one compartment (110) with the primary chamber (58).

Abstract: A fluid level indicator is provided for a master cylinder to generate a signal in response to the fluid level reaching a predetermined level. The fluid level indicator includes a carrier assembly for holding a magnet and moving the same within a master cylinder reservoir. A reed switch is activated by the magnet in a given position.

Abstract: A master cylinder includes a housing (12) with a bore (14) receiving a pair of pistons (32, 34). A bearing (50) extends from the housing (12) to one of the pistons (32) to define a passage (65) communicating fluid to a pressure chamber (40). The bearing (50), the passage (65) and the pressure chamber (40) extend outwardly of the housing bore (14) to permit the length of the housing to be reduced.

Abstract: A cover for a reservoir of a master cylinder. The housing of the master cylinder has a plurality of vertical slots located in a flange that surrounds the reservoir. Each of the vertical slots is connected to a locking surface by a slanted surface on the flange. A diaphragm has a series of tabs which are located in the slots to align expandable sections thereon with the reservoir. The cover has a lip with a series of detents located in the lip. To attach the cover to the housing, the detents are located in the slots in the flange and a vertical force is thereafter applied to compress the diaphragm between the flange and the cover. A horizontal force then moves the detents from the slots and over the slanted surface to the locking surface to maintain the seal between the housing and the cover.

Abstract: A drum brake assembly includes a backing plate for supporting a pair of brake shoes and a hydraulic actuator which cooperates with the pair of brake shoes to urge the latter into a braking position. A parking lever is pivotally mounted on one of the brake shoes and a strut connects the parking lever with the other brake shoe such that rotation of the parking lever when the parking brake is applied urges the pair of brake shoes into a braking position. In order to connect the strut to the other brake shoe while at the same time eliminating any rattle between the pair of brake shoes and the struts, a spring clip releasably connects with the other brake shoe and resiliently engages the strut to bias the latter toward the one brake shoe. The spring clip is substantially U-shaped with at least one opening for receiving the strut and for maintaining the strut in juxtaposition to the other brake shoe.