A pneumatic braking device for a utility vehicle includes at least one pneumatically controllable spring accumulator for a parking brake of the utility vehicle and an electronic parking brake device. The electronic parking brake device has at least one electronic control unit, at least one bistable valve unit, at least one first valve unit by which a parking brake of a trailer of the utility vehicle can be deactivated when activating the parking brake of the utility vehicle, at least one second valve device which can be connected in such a way that when there is a decrease in the system pressure for supplying the parking brake of the trailer, the parking brake of the trailer can be activated, and a traction vehicle protection valve.

A pneumatic braking device for a utility vehicle includes at least one pneumatically controllable spring accumulator for a parking brake of the utility vehicle and an electronic parking brake device. The electronic parking brake device has at least one electronic control unit, at least one bistable valve unit, at least one first valve unit by which a parking brake of a trailer of the utility vehicle can be deactivated when activating the parking brake of the utility vehicle, at least one second valve device which can be connected in such a way that when there is a decrease in the system pressure for supplying the parking brake of the trailer, the parking brake of the trailer can be activated, and a traction vehicle protection valve.

A pneumatic braking device for a utility vehicle includes at least one pneumatically controllable spring accumulator for a parking brake of the utility vehicle with an electronic parking brake device. The electronic parking brake device has at least one electronic control unit, at least one first bistable valve unit, at least one second bistable valve unit, at least one valve device which can be connected in such a way that when there is a decrease in the system pressure for supplying the parking brake of the trailer of the traction vehicle, the parking brake of the trailer can be activated, and a traction vehicle protection valve.

An automatic retainer valve includes a body defining a piston passageway and at least one piston positioned within the piston passageway, a brake pipe and reference volume in fluid communication with a first end of the valve, a brake cylinder in fluid communication with a second end of the valve, and an exhaust port defined in the body and positioned between the first and second ends of the valve. Pressurized fluid may be vented from the brake cylinder via the exhaust port upon a brake cylinder pressure exceeding a reference volume pressure. The brake cylinder pressure may push the at least one piston towards the first end of the valve until the brake cylinder pressure equalizes with the reference volume pressure.

An automatic retainer valve includes a body defining a piston passageway and at least one piston positioned within the piston passageway, a brake pipe and reference volume in fluid communication with a first end of the valve, a brake cylinder in fluid communication with a second end of the valve, and an exhaust port defined in the body and positioned between the first and second ends of the valve. Pressurized fluid may be vented from the brake cylinder via the exhaust port upon a brake cylinder pressure exceeding a reference volume pressure. The brake cylinder pressure may push the at least one piston towards the first end of the valve until the brake cylinder pressure equalizes with the reference volume pressure.

An electronic controller includes an electrical input and an electrical output. The electronic controller is adapted to receive an electronic status signal at the electrical input. The electronic status signal is indicative of a pneumatic pressure in a supply line communicating pneumatic fluid between a towing portion of a vehicle and a towed portion of the vehicle. The electronic controller is also adapted to transmit an electronic control signal from the electrical output to an associated valve, based on the electronic status signal, for controlling delivery of a pneumatic control signal from the towing portion of the vehicle to the towed portion of the vehicle.

An electronic controller includes an electrical input and an electrical output. The electronic controller is adapted to receive an electronic status signal at the electrical input. The electronic status signal is indicative of a pneumatic pressure in a supply line communicating pneumatic fluid between a towing portion of a vehicle and a towed portion of the vehicle. The electronic controller is also adapted to transmit an electronic control signal from the electrical output to an associated valve, based on the electronic status signal, for controlling delivery of a pneumatic control signal from the towing portion of the vehicle to the towed portion of the vehicle.

When a leak occurs in one service circuit of a multi-circuit braking system, the leak can prevent replenishing the non-leaking service reservoir. To address this problem, a shared backup reservoir can be used to replenish the non-leaking service reservoir. A valve can be used to allow flow from the backup reservoir to whichever service reservoir is under higher pressure, as low pressure would indicate a leak. Additional valve(s) can be used to impede flow from the service reservoirs to the backup reservoir to prevent the service reservoirs from being drained if the backup reservoir is subject to a leak.