The disclosure relates to a pneumatic braking system comprising a service brake actuator; an electro-pneumatic modulator unit for receiving an air control pressure representative of a driver's braking request; delivering, by a regulation unit, a modulated air pressure to a service brake chamber; a parking brake actuator; a parking brake unit for delivering a second air pressure to a parking brake pneumatic chamber; and an isolation device for when the isolation device is electrically energized, preventing the delivery of the air control pressure to the regulation unit, and for when the isolation device is not electrically energized, allowing the delivery of air control pressure to the regulation unit when the second air pressure is higher than a threshold, and preventing the delivery of air control pressure to the regulation unit when the second air pressure is lower than the threshold.

In a work vehicle, a through-hole in a stay includes first and second regions. When a grip is pulled in an unlocked state in which a collar is located inside the first region and a grip assembly is not locked inside the through-hole, a state is transitioned into a locked state in which a compression spring is compressed by a pin and a plain washer, a brake lever rotates, a claw moves toward a notch, and a rod is located inside the second region and the grip assembly is locked inside the through-hole. When a brake pedal is stepped on in this locked state, the claw and the notch engage with each other, and the brake pedal is locked.

A control method for controlling a spring loaded brake actuator (9) comprising a first chamber (Ch1) to receive a parking brake pressure (PBR) acting against a main spring (92), and a second chamber (Ch2) to receive a service brake pressure (SB) for applying a service brake force, the method comprising a circumstantial selection of one control law among a set of control laws comprising two or more compound control laws: where the first compound control law (CL1), known as anti-compound mode, is such the service brake pressure (SB) is electronically controlled such that the resulting total braking force (F) does not exceed a first upper limit (UL1) corresponding to the force of the main spring (92) when the parking brake pressure (PBR) is substantially null, where the second compound control law (CL2), known as controlled-compound mode, is such that the service brake pressure (SB) is electronically controlled such that the resulting total braking force (F) does not exceed a second upper limit (UL2) higher than the first upper limit.

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.

Spring failure detection systems include an air brake cylinder having a spring axially extending therein, a sensor coupled to the air brake cylinder and configured to sense forces applied to the air brake cylinder, an indicator coupled to the sensor and configured to indicate failure of the spring based on the forces sensed by the sensor, and a controller in communication with the sensor and configured to control the indicator. Methods for detecting failure of a spring are also disclosed.

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.

Various examples of brake actuators are provided. In one example, a brake actuator includes a parking brake chamber defined by a spring housing and an adapter base. The parking brake chamber includes a parking diaphragm that has an opening and the parking diaphragm is disposed between the spring housing and the adapter base which divides the brake spring chamber into a spring volume and a release volume, with the spring volume of the brake spring chamber being sealed from atmosphere. The parking brake chamber also includes a piston that is disposed in the spring volume and is in contact with the parking diaphragm, and the piston includes a piston passageway through the piston to allow air flow between the release volume and the spring volume.

A pneumatic spring brake cylinder is provided for brake systems of vehicles, including a housing in which a spring brake piston loaded by an accumulator spring and connected to a spring brake piston tube is guided in a movable manner, and an emergency release device for the emergency release of the spring brake piston in the event of a drop in pressure. The emergency release device contains a spindle which can be rotated relative to the spring brake cylinder and which can be screwed in a nut that is held in a rotationally fixed manner in the spring brake piston tube by a form-fitting connection. The nut interacts with an axial stop on the spring brake piston in order to trigger a release movement against the effect of the accumulator spring. The formfitting connection is formed between an outer polygonal profiled section of the outer circumference of the nut in a circumferential direction and a complementary circumferential inner polygonal profiled section on the inner circumference of an intermediate bushing and between an outer polygonal profiled section of the outer circumference of the intermediate bushing in the circumferential direction and a complementary circumferential inner polygonal profiled section on the inner circumference of the spring brake piston tube.

A spring-type brake cylinder that includes a compression spring, a pressure chamber, a dividing wall disposed between the compression spring and the pressure chamber, a piston having an inner wall and a bottom, and a nut disposed inside the piston and configured to be held on a release bolt. A support structure is disposed inside the piston and configured to abut against the nut while the release bolt is screwed into the nut. The piston comprises a first retaining structure and a second retaining structure, the first retaining structure configured to hold the support structure in an assembly position and the second retaining structure configured to hold the support structure in a drive position. The support structure is moveable from the assembly position to the drive position by a movement of the nut relative to the piston.

A spring-loaded brake actuator includes a push rod that can be coupled to a braking element of a brake, an energy accumulator which is designed to apply a braking force onto the push rod via a coupling mechanism, a drive, which is designed to hold the push rod in a brake release position against the force of the energy accumulator, and an auxiliary release device, with which the transmission of the braking force from the energy accumulator to the push rod can be blocked independently of the drive, in which the coupling mechanism has two coupling members which are in engagement with one another via a claw clutch, and in that the auxiliary release device has an actuating element which is designed to bring the claws of the claw clutch into a non-engaged position in a direction of movement transverse to the force transmission direction.