This invention is related to a diaphragm-diaphragm spring brake actuator with internal ventilation designed to decrease the actuator breakdowns used in the air brake system of heavy vehicles such as trucks lorries, trailers and busses.

A vehicle spring brake having a parking brake housing that defines a parking brake chamber and a service brake housing that defines a service brake chamber. A flexible membrane separates the parking brake chamber from the service brake chamber and flexes into and out of the service brake chamber based upon a pressure differential between an air pressure in the parking brake chamber and an air pressure in the service brake chamber. A pushrod extends out of the service brake housing when the flexible membrane flexes into the service brake chamber and retracts into the service brake housing when the flexible membrane flexes back out of the service brake chamber. A control valve controls the pressure differential to thereby control movement of the flexible membrane and the pushrod.

A spring brake actuator (1) for a vehicle, in particular a parking or emergency brake actuator, for use in a commercial vehicle, includes a cylinder housing (2) having a cylinder housing base (5) and a spring seat (7) on the base, a spring brake piston (9) located in the cylinder housing (5) for applying a braking force, and a compression spring (11) arranged between the spring seat (7) and the spring brake piston (9). The cylinder housing (2) is divided into a spring chamber (12) and a pressure chamber (14), the compression spring (11) being arranged in the spring chamber (12) and the pressure chamber (14) being supplied with pressurized fluid. An elastically deformable diaphragm (16) is sealingly mounted to the cylinder housing (2), with an inner periphery (18) sealingly mounted to the spring brake piston (9) to fluid-tightly isolate the pressure chamber (14) from the spring chamber (12).

A disc brake device for a vehicle, the disc brake device is equipped with: a piston slidably fitted into a cylinder hole provided in one arm section of a brake caliper, and capable of pressing against one friction pad; a shim plate mounted on a back plate of the one friction pad and interposed between the back plate and the piston; and a pressing device that applies pressing force to the piston while causing rotational force to act on the piston. Multiple protrusions protruding toward the piston are provided, with intervals between the protrusions, on the back plate of the friction pad facing the piston with the shim plate therebetween, and multiple engaging holes, into which the multiple protrusions are fitted, are provided on the shim plate so as to prevent the shim plate from rotating together with the piston due to the rotational force.

A pneumatic brake actuator has a spring brake actuator with spring and spring brake pressure chambers, and a service brake actuator with service brake pressure and pushrod chambers. A control valve has a seal that is moveable between an open position and a closed position for regulating fluid flow between the spring chamber and service brake pressure chamber. A first surface of the seal is in fluid communication with the service brake pressure chamber and a second surface of the seal is in fluid communication with a valve chamber that is not in fluid communication with the service brake pressure chamber or spring chamber. The seal moves between its open and closed positions based on a pressure in the service brake pressure chamber. Movement of the seal is not dependent on the rate of flow of fluid between the spring chamber and the service brake pressure chamber.

A pneumatic brake actuator has a spring brake actuator with spring and spring brake pressure chambers, and a service brake actuator with service brake pressure and pushrod chambers. A control valve has a seal that is moveable between an open position and a closed position for regulating fluid flow between the spring chamber and service brake pressure chamber. A first surface of the seal is in fluid communication with the service brake pressure chamber and a second surface of the seal is in fluid communication with a valve chamber that is not in fluid communication with the service brake pressure chamber or spring chamber. The seal moves between its open and closed positions based on a pressure in the service brake pressure chamber. Movement of the seal is not dependent on the rate of flow of fluid between the spring chamber and the service brake pressure chamber.

The present invention relates to a brake system comprising an actuating part and a brake part, the actuating part having a pressure chamber and a restoring section, the pressure chamber and the restoring section being separated from one another in a fluid-tight manner by way of a piston, it being possible for the piston to be fixed on an engagement element in such a way that a movement of the piston brings about a movement of the engagement element, the engagement element protruding into the brake part and having, in the brake part, a force section which is designed to transmit a force to a brake means, the brake part and the predominant part of the actuating part being arranged in a housing.

A plug for sealing an aperture in a brake actuator housing is provided that provides improvements in installation and retention of the plug and protection for sealing surfaces. The plug includes a retention member including a body defining an aperture configured for alignment with the actuator housing aperture along an axis extending through the apertures. The retention member further includes a plurality of alignment tabs extending radially from the body. The tabs are configured to be received within a plurality of notches formed in a retaining ring affixed to the housing when the retention member is disposed in an unlocked position and configured to be disposed on a first side of the retaining ring when the retention member is rotated about the axis to a locked position. The plug further includes a seal configured to be received within the aperture in the body. The seal closes the second aperture.

A brake device for an elevator hoisting machine includes: a rod movable in an axial direction; a plurality of pistons provided to the rod so as to be arranged side by side in the axial direction; a cylinder configured to accommodate each of the pistons therein and including a pressure control chamber formed between the cylinder and each of the pistons; a lining provided to the rod so as to be capable of coming into contact with a contacted body; and a spring device configured to press the pistons in a direction in which the lining is pressed against the contacted body. Gaps are respectively formed between at least one of the plurality of pistons and the rod and between pistons adjacent to each other. Each of the pistons is configured to be driven by a change in air pressure in the pressure control chamber.

A spring brake actuator (2) for use in a commercial vehicle includes a cylinder housing (4) including a spring brake piston (10) for applying a braking force, a spring guide (12) attached to the spring brake piston (10). The spring guide (12) includes a valve (14) and a retaining device (16) for retaining the valve (14). The retaining device (16) includes a basic body (34) and clamping portions (36) for clamping the retaining device (16) to the spring guide (12). The clamping portions (36) are arranged at the basic body (34) along a circumference (38) thereof, and the clamping portions (36) are spaced apart from each other forming slits (40) between the clamping portions (36) to allow for a circulation of air through the slits (40).