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.

Abstract: A valve assembly including a housing (24?) provided with an inlet port (12?), a delivery port (14?), and an exhaust port (16?), the valve assembly further including a first movable element (32?), a first valve member (34a?) and a second valve member (26a?), the first movable element (32?) being engageable with the first valve member (34a?), engagement of the first valve member (34a?) and first movable element (32?) substantially preventing flow of fluid between the inlet port (12?) and the delivery port (14?), and the first movable element (32?) also being engageable with the second valve member (26a?), engagement of the second valve member (26a?) with the first movable element (32?) substantially preventing flow of fluid between the delivery port (14?) and the exhaust port (16?), the valve assembly further including a second movable element (26?) which divides the housing (24?) into a control chamber (22?) and a main chamber (30?) and which is movable relative to the housing (24?) under the influence of flui

Abstract: A valve assembly including a housing (24?) provided with an inlet port (12?), a delivery port (14?), and an exhaust port (16?), the valve assembly further including a first movable element (32?), a first valve member (34a?) and a second valve member (26a?), the first movable element (32?) being engageable with the first valve member (34a?), engagement of the first valve member (34a?) and first movable element (32?) substantially preventing flow of fluid between the inlet port (12?) and the delivery port (14?), and the first movable element (32?) also being engageable with the second valve member (26a?), engagement of the second valve member (26a?) with the first movable element (32?) substantially preventing flow of fluid between the delivery port (14?) and the exhaust port (16?), the valve assembly further including a second movable element (26?) which divides the housing (24?) into a control chamber (22?) and a main chamber (30?) and which is movable relative to the housing (24?) under the influence of flui

Abstract: A vehicle braking system comprising a controller responsive to wheel speed signals from at least two wheel speed sensors for sensing skid conditions of at least two wheels and for generating skid control instructions; a plurality of wheel brakes responsive to fluid pressure, hereinafter referred to as brake pressure, supplied thereto; a supply device, comprising a common supply valve, for supplying brake pressure to the brakes from a fluid pressure supply in accordance with a brake operating signal; and a skid controller controlled by the skid control instructions for controlling the brake pressure in a plurality of cycles each of which comprises a pressure reduction phase and a pressure increase phase, and a first comparitor to compare the co-efficient of friction of the lower friction surface with a predetermined threshold, and/or a second comparitor to compare the relative values of the co-efficients of friction of the surfaces with which at least two of the wheels are engaged and a device to operate the s

Abstract: An anti-skid braking system for a vehicle comprising a supply of fluid for actuating a plurality of wheel brakes, a skid control unit interposed between the fluid supply and the brakes, sensors to detect the skidding of a plurality of wheels and actuating means responsive to skid signals from the sensors and adapted to actuate the skid control unit to relive the fluid pressure at the brake of the wheel at impending lock by means of a plurality of successive first brake release periods. In order to reduce yawing, when an impending skid condition is detected at one wheel, the skid control unit is arranged to induce second, shorter brake release periods in one or more of the brakes of the wheels not at impending lock.