A vehicle locked wheel detector detects initial trailer movement or enablement thereof, for example using a spring brake air pressure switch. The outputs from ABS wheel rotation sensors are monitored to determine whether all wheels are rotating. If one wheel is not rotating, then a locked wheel indicator alerts the driver that one of the wheels may be locked. In some embodiments, if both wheels on one side of the trailer are either stationary or rotating below a threshold speed and the wheels on the opposite side are rotating relatively more quickly, then the trailer is presumed to be pivoting around a sharp turn, and so the wheels will be presumed to be rolling. A finite temporal-spatial interval subsequent to initial trailer movement is defined within which wheel lock can be detected, and upon expiration of the temporal-spatial interval the ABS operates in a normal manner.

A brake system for a trailer has first and second pneumatic circuits for supplying air pressure to the wheel ends on the trailer. The air pressure to brake devices at the wheel ends is controllable via a first brake ECU. First and second pressure control valves control pressure from the pneumatic circuits to the respective wheel ends. The system further has a second ECU adapted to electrically control the actuation of the pressure control valves.

A pressure sensing system of a pneumatic spring brake chamber for a vehicle according to an embodiment of the present disclosure includes a plurality of pressure sensors configured to measure pressure in a pressure chamber formed between a piston and an adapter housing and a service chamber formed between the adapter housing and a diaphragm, a control box electrically connected to the plurality of pressure sensors, and an indicator electrically coupled to the control box, wherein the control box is wired for power supply and output voltage to the plurality of pressure sensors, and the indicator located in a vehicle driver's seat is configured to generate an alarm about an abnormal situation of the pneumatic spring brake chamber for a vehicle based on pressure measurement values in the pressure chamber and the service chamber through the plurality of pressure sensors.

An electropneumatic brake system for a vehicle has a parking brake system having a parking brake valve unit constructed to adjust a parking brake pressure on at least one spring loading connection in accordance with a pilot control pressure. The valve unit has a pilot control unit which in accordance with an electronic parking brake signal adjusts the pilot control pressure on a pilot control path. The parking brake unit has an additional brake pressure connection which is or can be pneumatically connected to the pilot control path to introduce an emergency release pressure. The introduction of the emergency release pressure on the additional brake pressure connection causes the adjustment of the parking brake pressure on at least one spring loading connection. A first control unit is configured to provide the electronic parking brake signal to the valve unit. The electropneumatic brake system can have an emergency release valve unit.

An air parking brake electric control valve includes an air valve unit and a self-lock unit. The air valve unit includes a main valve body, an auxiliary valve body, a valve core and a first electromagnetic assembly. The valve core is driven by the first electromagnetic assembly to move between a first action position and a second action position. The self-lock unit is disposed on the auxiliary valve body, and includes a second electromagnetic assembly. The second electromagnetic assembly includes a movable column operable to move between a release position and a lock position.

A drum brake, in particular for a utility vehicle, has a brake drum, which is rotatably mounted about a rotational axis, and multiple brake shoes, which are mounted in a receiving area of the brake drum and each of which has a friction lining support and a friction lining arranged thereon. The brake shoes can be pressed against a brake drum casing inner surface, which is designed as a friction surface, in a radial direction relative to a rotational axis of the brake drum. The interior of the drum brake is equipped with a brake cylinder assembly which is rotationally fixed to an armature housing for actuating the brake shoes. A respective pressing wedge is arranged on the friction lining support face facing away from the friction lining. The pressing wedge lies on a wedge mechanism which can be moved in a parallel manner relative to the rotational axis of the brake drum. The wedge mechanism can be moved from a non-braking position into a braking position by moving the service brake piston of the brake cylinder assembly in a parallel manner relative to the rotational axis of the brake drum.

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.

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.

A parking brake system of a tipper vehicle having a tiltable tipper body is described. The system comprises a parking brake having a brake chamber which is pressurizable for releasing the parking brake. A valve device is in fluid communication with the brake chamber, the valve device comprising an exhaust port. The valve device has an activated state in which the brake chamber is in fluid communication with the exhaust port whereby air from the brake chamber is discharged, thereby applying the parking brake, and an inactivated state in which said fluid communication is disconnected. Upon receipt of a tipping signal, a neutral gear signal and a low speed signal, and upon detecting that the parking brake is still in the released state, the valve device is changed from the inactivated state to the activated state in order to exhaust air from the brake chamber, causing the parking brake to become changed to the applied state.

A parking brake control module using pneumatic logic to control a parking brake on a railway vehicle. The control module includes a brake pipe passageway, a reservoir passageway, a reservoir release valve, and an actuation cylinder vent valve. The control module applies or releases the parking brake based on pressures of the brake pipe and reservoir. A method uses pneumatic logic to control a parking brake on a railway car. The parking brake is applied when the brake pipe pressure falls below a lower brake pipe pressure threshold and is released when the brake pipe pressure exceeds an upper brake pipe pressure threshold and the reservoir pressure exceeds a reservoir pressure threshold. A hold valve can allow an operator to manually prevent the release of the parking brake.