Abstract: A bushing assembly is provided for a spring brake actuator of a vehicle air braking system. The bushing assembly comprises a single-piece bushing member made of a material that is homogenous throughout the bushing member. The bushing member includes a first rib structure that faces one axial direction of the bushing member and a second rib structure that faces an opposite axial direction of the bushing member.

Abstract: A bushing assembly is provided for a spring brake actuator of a vehicle air braking system. The bushing assembly comprises a single-piece bushing member made of a material that is homogenous throughout the bushing member. The bushing member includes a first rib structure that faces one axial direction of the bushing member and a second rib structure that faces an opposite axial direction of the bushing member.

Abstract: A brake actuator comprises a housing having an end wall and a pushrod projecting through an opening in the end wall and terminating at a movable plate in the housing. A spring is enclosed in the housing and surrounds the pushrod. At least one unitary resilient member is disposed on the push rod proximate to the end wall and partially extends through the opening for centering the spring around an axis of the pushrod and restricting contamination into the housing. The unitary resilient member comprises a central aperture and an annular flange surrounding the central aperture. At least one section of a collar radially outward from the annular flange has a thickness less than half of the annular flange thickness for constraining movement of the spring and the push rod in a radial direction.

Abstract: A brake actuator comprises a housing having an end wall and a pushrod projecting through an opening in the end wall and terminating at a movable plate in the housing. A spring is enclosed in the housing and surrounds the pushrod. At least one unitary resilient member is disposed on the push rod proximate to the end wall and partially extends through the opening for centering the spring around an axis of the pushrod and restricting contamination into the housing. The unitary resilient member comprises a central aperture and an annular flange surrounding the central aperture. At least one section of a collar radially outward from the annular flange has a thickness less than half of the annular flange thickness for constraining movement of the spring and the push rod in a radial direction.

Abstract: In a brake actuator including a plurality of actuator housing portions, a diaphragm seal, partially delimiting a parking brake de-actuation chamber, is retained between adjacent actuator housing portions, and an elastic element disposed between the diaphragm seal and one of the housing portions opposes expansion of the parking brake de-actuation chamber. A push rod extends into and out of a service brake actuation chamber upon respective release of fluid pressure from the parking brake de-actuation chamber and supply of fluid pressure to the parking brake de-actuation chamber. In order to constrain a central portion of the diaphragm seal for movement together with both the push rod and a piston, a clamping arrangement is used to axially clamp the central diaphragm seal portion between an end of the push rod and a surface of the piston.

Abstract: A brake system and a valve device for a brake system are provided which provide at least partial front brake actuation in the event of a failure in the front brake pneumatic supply circuit. The valve device may be configured as a biased orifice double check valve which permits compressed air flow from the front brake pneumatic supply circuit to a front brake actuator during normal brake operation, but in the event of lack of sufficient front brake pneumatic pressure permits compressed air to be supplied to the front brake actuator from a rear brake pneumatic supply circuit, as well as permitting compressed air in the front brake actuator to be ventilated back through the rear brake pneumatic supply circuit when the brake is released.

Abstract: A fluid pressure operable actuator includes a housing, with an end wall, and a pushrod projecting through an opening in the end wall for reciprocation upon service pressure application or release. A shield, configured as an annulus, is disposed on the pushrod to restrict contamination of an interior chamber of the actuator housing through a gap existing between an edge of the opening and a pushrod outer surface. To facilitate connecting the shield and the pushrod together, the annulus has a slit with an enlarged void at a radially outer end of the slit. This enlarged void engages an outer pushrod surface as the shield and the pushrod are joined.

Abstract: A spring-type brake actuator for a pneumatically-operated vehicle brake is provided, in which the parking brake release piston is formed from at least one stamped actuator piston plate, preferably a stamped aluminum plate. Preferably the biasing force of the power spring of the spring brake actuator bears on a stamped spring seat cap element which is interposed between the power spring and the stamped actuator piston plate. In addition, the parking brake release piston flexible diaphragm may be captured between the stamped actuator piston plate and a stamped backing plate by affixing the backing plate to a joining member, where the joining member includes a threaded insert to receive a manually-actuated parking brake release actuation tool.

Abstract: A brake system and a valve device for a brake system are provided which provide at least partial front brake actuation in the event of a failure in the front brake pneumatic supply circuit. The valve device may be configured as a biased orifice double check valve which permits compressed air flow from the front brake pneumatic supply circuit to a front brake actuator during normal brake operation, but in the event of lack of sufficient front brake pneumatic pressure permits compressed air to be supplied to the front brake actuator from a rear brake pneumatic supply circuit, as well as permitting compressed air in the front brake actuator to be ventilated back through the rear brake pneumatic supply circuit when the brake is released.

Abstract: A spring-type brake actuator for a pneumatically-operated vehicle brake is provided, in which the portion of the brake actuator containing the parking brake actuation power spring is arranged to be vented to atmosphere but not to permit entry of outside environmental air into the power spring chamber, the spring-type brake actuator being provided with an internal breather valve which permits clean dry air from the parking brake release chamber to enter the power spring chamber which the pressure difference between the chambers falls to within a predetermined pressure range.

Abstract: A fluid pressure operable actuator includes a housing, with an end wall, and a pushrod projecting through an opening in the end wall for reciprocation upon service pressure application or release. A shield, configured as an annulus, is disposed on the pushrod to restrict contamination of an interior chamber of the actuator housing through a gap existing between an edge of the opening and a pushrod outer surface. To facilitate connecting the shield and the pushrod together, the annulus has a slit with an enlarged void at a radially outer end of the slit. This enlarged void engages an outer pushrod surface as the shield and the pushrod are joined.

Abstract: A brake actuator having a plurality of actuator housing portions includes a diaphragm seal partially delimiting a parking brake de-actuation chamber and retained between adjacent portions of the housing. To produce brake actuation upon depressurization of the parking brake de-actuation chamber, a push rod extends into and out of a service brake actuation chamber upon release of fluid pressure from and supply of fluid pressure to the chamber. A clip or similar element receivable over the end section of the push rod is securable on the end section to compress the diaphragm seal axially relative to the push rod against a seat carried by the push rod while permitting a radial inner edge of the diaphragm seal to remain spaced from an outer surface of the end section.

Abstract: A spring-type brake actuator for a pneumatically-operated vehicle brake is provided, in which the portion of the brake actuator containing the parking brake actuation power spring is arranged to be vented to atmosphere but not to permit entry of outside environmental air into the power spring chamber, the spring-type brake actuator being provided with an internal breather valve which permits clean dry air from the parking brake release chamber to enter the power spring chamber which the pressure difference between the chambers falls to within a predetermined pressure range.

Abstract: A spring-type brake actuator for a pneumatically-operated vehicle brake is provided, in which the parking brake release piston is formed from at least one stamped actuator piston plate, preferably a stamped aluminum plate. Preferably the biasing force of the power spring of the spring brake actuator bears on a stamped spring seat cap element which is interposed between the power spring and the stamped actuator piston plate. In addition, the parking brake release piston flexible diaphragm may be captured between the stamped actuator piston plate and a stamped backing plate by affixing the backing plate to a joining member, where the joining member includes a threaded insert to receive a manually-actuated parking brake release actuation tool.

Abstract: In a brake actuator including a plurality of actuator housing portions, a diaphragm seal, partially delimiting a parking brake de-actuation chamber, is retained between adjacent actuator housing portions, and an elastic element disposed between the diaphragm seal and one of the housing portions opposes expansion of the parking brake de-actuation chamber. A push rod extends into and out of a service brake actuation chamber upon respective release of fluid pressure from the parking brake de-actuation chamber and supply of fluid pressure to the parking brake de-actuation chamber. In order to constrain a central portion of the diaphragm seal for movement together with both the push rod and a piston, a clamping arrangement is used to axially clamp the central diaphragm seal portion between an end of the push rod and a surface of the piston.

Abstract: A brake actuator having a plurality of actuator housing portions includes a diaphragm seal partially delimiting a parking brake de-actuation chamber and retained between adjacent portions of the housing. To produce brake actuation upon depressurization of the parking brake de-actuation chamber, a push rod extends into and out of a service brake actuation chamber upon release of fluid pressure from and supply of fluid pressure to the chamber. A clip or similar element receivable over the end section of the push rod is securable on the end section to compress the diaphragm seal axially relative to the push rod against a seat carried by the push rod while permitting a radial inner edge of the diaphragm seal to remain spaced from an outer surface of the end section.

Abstract: A mid-power spring brake actuator includes first, second, and third actuator housing portions, with the first actuator housing portion interposed between the second and third housing portions. A parking brake release actuator is received within the third housing portion, and a connecting shaft is attached at a first end to the parking brake release actuator and extends through a dividing wall defined by the first housing portion. A service brake apply actuator is received within at least one of the first and second housing portions. Between the dividing wall defined by the first housing portion and a second end of the connecting shaft, a brake actuator spring is provided, and a service brake actuation chamber is interposed between the brake actuator spring and the service brake apply actuator. A parking or emergency brake de-actuation chamber is defined between the parking brake release actuator and the first housing portion.

Abstract: A mid-power spring brake actuator includes first, second, and third actuator housing portions, with the first actuator housing portion interposed between the second and third housing portions. A parking brake release actuator is received within the third housing portion, and a connecting shaft is attached at a first end to the parking brake release actuator and extends through a dividing wall defined by the first housing portion. A service brake apply actuator is received within at least one of the first and second housing portions. Between the dividing wall defined by the first housing portion and a second end of the connecting shaft, a brake actuator spring is provided, and a service brake actuation chamber is interposed between the brake actuator spring and the service brake apply actuator. A parking or emergency brake de-actuation chamber is defined between the parking brake release actuator and the first housing portion.