Abstract: An air braking unit for use in an air braking system. The air braking unit is arranged to be positioned, in use, at a vehicle wheel, and comprises an inlet for receiving, in use, compressed air from a central source. At least one first valve is arranged to selectively allow compressed air from the inlet to enter a wheel brake chamber in use. At least one second valve is arranged to selectively allow air from the brake chamber to be released via an outlet to the atmosphere in use and control means controls the first and second valves to operate to selectively control the air pressure in the brake chamber in use.

Abstract: An electromagnetic valve comprises a yoke, a magnet having pole pieces defining a gap, a flexure assembly having one end attached to the yoke such that part of the flexure assembly extends into the gap, and a mechanism configured to polarize the magnetizable portion so that the extending part of the flexure assembly is attracted towards a pole piece by a magnetic force, thereby defining a valve state. The flexure assembly has at least one resilient portion and at least one magnetizable portion, wherein the extending part of the flexure assembly is movable between the pole pieces through an intermediate position towards which it is resiliently biased such that a resilient mechanical force is generated by deflecting the resilient portion from an undeflected position. The magnetizable portion and the resilient portion are configured such that the magnetic force defining the valve state is greater than the resilient mechanical force.

Abstract: An electromagnetic valve comprises a yoke, a magnet having pole pieces defining a gap, a flexure assembly having one end attached to the yoke such that part of the flexure assembly extends into the gap, and a mechanism configured to polarize the magnetizable portion so that the extending part of the flexure assembly is attracted towards a pole piece by a magnetic force, thereby defining a valve state. The flexure assembly has at least one resilient portion and at least one magnetizable portion, wherein the extending part of the flexure assembly is movable between the pole pieces through an intermediate position towards which it is resiliently biased such that a resilient mechanical force is generated by deflecting the resilient portion from an undeflected position. The magnetizable portion and the resilient portion are configured such that the magnetic force defining the valve state is greater than the resilient mechanical force.

Abstract: An electromagnetic valve comprises a yoke, a magnet having pole pieces defining a gap, a flexure assembly having one end attached to the yoke such that part of the flexure assembly extends into the gap, and a mechanism configured to polarize the magnetizable portion so that the extending part of the flexure assembly is attracted towards a pole piece by a magnetic force, thereby defining a valve state. The flexure assembly has at least one resilient portion and at least one magnetizable portion, wherein the extending part of the flexure assembly is movable between the pole pieces through an intermediate position towards which it is resiliently biased such that a resilient mechanical force is generated by deflecting the resilient portion from an undeflected position. The magnetizable portion and the resilient portion are configured such that the magnetic force defining the valve state is greater than the resilient mechanical force.