A control valve for an automatic parking brake having an inlet for coupling to a source a brake pipe pressure, an outlet for coupling to a control inlet of the automatic parking brake and a pilot for coupling to the source of brake pipe pressure. The control valve is moveable between a first position where the inlet is in communication with the outlet and a second position where the inlet and the outlet are isolated from each other in response to a predetermined amount of brake pipe pressure at the pilot. The control valve includes a spring biasing the control valve into the first position.

A brake actuator assembly including a pressure plate presenting an opening, a push rod that is coupled to the pressure plate, a diaphragm that is coupled to the pressure plate, and a retainer that engages the push rod. The push rod has an outer surface and at least one protrusion extending outward from the outer surface. The retainer engages the protrusion such that at least a portion of the diaphragm is positioned between the pressure plate and the retainer.

A method is for operating a vehicle's electropneumatic brake system. The brake system includes a service brake system and a parking brake system. The parking brake system includes a spring brake cylinder. A control signal for maintaining a spring brake pressurization pressure, which pressurizes the spring brake cylinder, is provided via a control unit. The provision of the control signal is suspended in at least one of a fault event and/or in the event of an electrical failure and/or in a diagnostic event of the control unit and thus automatically ending the maintenance of the spring brake pressurization pressure to ventilate the spring brake cylinder and thus initiating a spring brake failsafe braking operation of the vehicle via the parking brake system. The ventilation of the spring brake pressurization pressure is performed by a service brake ventilation function of the service brake system.

The invention relates to an emergency braking device comprising an actuator (2), a pressurizing circuit (3) supplying the actuator (2) via a control pressure and a discharge circuit (4), characterized in that the discharge circuit (4) comprises means (13, 14) for controlling the pressure and/or flow rate of the supply fluid of the actuator (2) during a discharge of the actuator, these control means (13, 14) being configured to define an intermediate pressure between a low pressure level and the control pressure of the actuator (2).

A spring brake chamber includes a first case, a second case, and a coupling case. The first case includes an open end, a closed end, and an open end portion. The open end portion of the first case includes a tapered outer positioning portion having a diameter that increases toward the open end. The coupling case couples the first case and the second case. The coupling case includes an open end closer to the first case and an open end portion. The open end portion of the coupling case includes a tapered inner positioning portion having a diameter that decreases toward the open end. The first case is positioned relative to the coupling case by attaching the outer positioning portion to an outer side of the inner positioning portion.

A spring brake actuator is for braking a wheel of a vehicle and has a push rod assembly having a base located in a service brake chamber and a push rod extending from a service brake chamber. Pneumatic activation of the spring brake actuator causes the push rod to further extend out of the service brake chamber to thereby engage a wheel brake with a wheel of the vehicle. Pneumatic deactivation of the spring brake actuator causes the push rod to retract back into the service brake chamber to thereby disengage the wheel brake from the wheel of the vehicle. The push rod extends between a first end portion that is fixed to the base and an opposite, second end portion that is removably coupled to the first end portion so that the second end portion is manually attachable and detachable from the push rod assembly.

A spring brake actuator has a combined housing including a first housing, a second housing, and connection part connecting the first housing and the second housing. Gas inlet ports are disposed along the circumference of the combined housing in a gas inlet port section. A mechanical connection section is disposed in the same axial space as the gas inlet portion section. A bayonet connection is arranged in the mechanical connection section, with gas inlet ports disposed between the bayonet elements. Port connectors may extend through recesses or holes and be threaded into the gas inlet ports, and which may block the bayonet connection and block relative rotation between the first and second housings. The connection part may include a ring shaped protrusion form fit with a protruding of the second housing, with the bayonet elements disposed at the opposite end of the connection part engaged with the first housing.

A resonator is described including a piezoelectric material with first and second electrodes provided on the piezoelectric material. An acoustic metamaterial at least partially surrounds an active region of the resonator.

A control valve for an automatic parking brake having an inlet for coupling to a source a brake pipe pressure, an outlet for coupling to a control inlet of the automatic parking brake and a pilot for coupling to the source of brake pipe pressure. The control valve is moveable between a first position where the inlet is in communication with the outlet and a second position where the inlet and the outlet are isolated from each other in response to a predetermined amount of brake pipe pressure at the pilot. The control valve includes a spring biasing the control valve into the first position.

A brake cylinder with a cylinder body having a first flange extending radially therefrom to form a radial edge with a bevel and a non-pressure head having a second flange extending radially therefrom, wherein the second flange is spaced apart from the first flange to define a first gap and includes an angled portion that extends over the bevel of the first flange to define a second gap in communication with the first gap. The two flanges form a gap in communication with the interior of the brake cylinder that extends outwardly to a V-shaped gap between the bevel of the first flange and the angled portion of the second flange to define a brake cylinder vent. The vent may be limited to four predetermined locations spaced equidistantly about the brake cylinder or the vent may extend circumferentially about the brake cylinder.