Abstract: A suspension unit comprising a telescopic damper with a surrounding coil spring has a rotatable cam sleeve, an intermediate sleeve and a fixed end sleeve, the latter two sleeves being adjustable relative to each other both angularly and axially, but normally providing a fixed reaction for normal adjustment of the spring length by rotation of the cam sleeve, which may be of identical form to the intermediate sleeve, each having an axial cam profile at one end and axially extending projections of different lengths at its other end.

Abstract: A control valve assembly for use in a pump-operated vehicle hydraulic braking system as disclosed in which the output from the pump flows through the control valve, which selectively directs the output to steering gear of the vehicle or to an accumulator for connection to brakes. The valve is also provided with a bleed passage through which a proportion of the output is continuously supplied to the steering gear.

Abstract: In a fluid pressure-operated anti-skid braking system for rail and other vehicles operating fluid from a supply for actuating a wheel brake is supplied to the brake through a fluid-flow control valve interposed in the line between the supply and the brake. Deceleration responsive sensors responsive to a skid signal are incorporated for operating the valve to relieve the brake pressure of the fluid supplied to the brake when the deceleration of the wheel is excessive and exceeds a predetermined value. The valve incorporates a fluid pressure memory chamber for sensing the skid pressure, and the memory chamber provides a datum or changeover point between first and second successive stages of brake re-application following a skid.

Abstract: In a disc brake of the sliding yoke reaction type the noise due to "squeal" or "twitter" is substantially eliminated by resiliently biassing the yoke in grooves in a stationary member so that it engages an upper face of a groove on one side of the brake and a lower face of a groove on the other side. A dampening assembly may be provided between the yoke and a complementary face of one of the grooves. Alternatively the noise may be reduced by providing an abutment of stepped outline on the yoke which engages a friction pad assembly to apply it to the disc when the brake is applied.

Abstract: A self-energizing disc brake is operated by an actuator which moves spreading pressure plates angularly in opposite directions to apply rotatable friction discs to radial surfaces in a stationary housing, and the actuator comprises a wedge for separating lugs on the plates, a spring for urging the wedge in a direction to separate the lugs, and a piston working in a cylinder bore for urging the wedge in the opposite direction when the cylinder is pressurized.

Abstract: In a fluid-pressure operated servo-motor in which an output force applied to an output member is augmented by differential pressures applied to opposite faces of a movable wall, a one-piece reaction plate of corrugated outline is interposed between the input and output members and the movable wall. In use the reaction plate transmits a load from the movable wall to the output member and transmits a reactive proportion of the output load back to the input member.

Abstract: In a pressure differential warning actuator for detecting when a differential between the pressure of separate brake circuits of an hydraulic braking system exceeds a predetermined value, at least two separate pistons work in separate bore portions in a common housing and are movable between a neutral position when the predetermined value of the differential pressure is not exceeded and an operative position, in which an indicator mechanism is actuated, when the predetermined value is exceeded, and the pistons act through a deformable assembly to restore them from the operative position to the neutral position when the differential is reduced to less than the predetermined value.

Abstract: In a modulator assembly for a vehicle anti-skid braking system comprising a housing having a chamber of which the effective volume is variable by an expander piston to modulate the pressure supplied to a wheel brake in accordance with skid conditions, the chamber comprises first and second compartments, and a valve assembly is located in the housing to control communication between the compartments. The valve assembly is closed when the expander piston is in an advanced position in which the effective volume of the chamber is substantially at a minimum so that a first area of the piston is exposed only to pressure in one of the compartments, and the valve assembly is open when the expander piston is retracted away from the advanced position so that a second area of the piston which is greater than the first is exposed to pressure in both compartments.

Abstract: A hydraulic brake actuator having a piston slidable in a cylinder for hydraulic service brake operation also incorporates a mechanical linkage for handbrake operation. The mechanical linkage comprises a cranked shaft journalled in a closed end wall of the cylinder, a linearly displaceable peg and a strut interconnecting the cranked shaft and peg such that rotation of the cranked shaft causes linear displacement of the peg. The cranked part of the shaft of the strut and the peg are preferably contained wholly within a hydraulic working chamber defined by the piston and cylinder so that when the service brake and handbrake are applied simultaneously, movement of the mechanical components does not cause a change in the volume of the chamber and prevailing hydraulic fluid pressure will not therefore affect such movement.

Abstract: A vehicle load sensing arrangement for use with a vehicle braking system comprises an input member operating in a first bore and being subjected to the force of a road spring, a spring, such as a robust helical coil spring, subjecting the input member to a force in opposition to the road spring force, a valve having a valve member in a second bore which has a cross-sectional area smaller than the first bore, the valve member and input member being substantially in alignment, and an elastomeric member located between the input member and the valve member. The arrangement is such that only a proportion of the road spring force applied to the input member in excess of the coil spring force is transmitted by the elastomeric member to the valve member, the remainder of that excess force being transmitted to the sprung part of the vehicle.

Abstract: The brake is of the type comprising a carrier member for fixing to a vehicle, a caliper member slidably mounted on the carrier member and an actuator for urging a first friction pad onto one side of a rotatable disc to cause the caliper member to slide relative to the carrier member and apply a second friction pad to the other side of the disc. The sliding connection is provided by a pair of pins slidable in openings in one of the members, preferably the carrier member, and releasably secured to the other of the members. To prevent binding of the pins in their openings, at least one of the openings is made diametrically oversized and the associated pin is urged into an eccentric position in direct sliding contact with the wall of its opening by means of a leaf spring which also resiliently urges the pads into position in the carrier member. When both pins extend into radially oversized openings, they are relieved of drag forces which arise on brake application.

Abstract: The invention provides a sliding caliper disc brake in which a caliper carrying an indirectly operated friction pad assembly is slidably mounted on a single pin relative to a fixed torque plate carrying a directly operated friction pad assembly, at least one further pin being provided for retaining the friction pad assemblies in position in relation to the caliper and torque plate respectively and the further pin, or at least one of the further pins when more than one is provided, being arranged to prevent rotation of the caliper about the drag transmitting pin.

Abstract: An automatic slack adjuster assembly is provided in or for a vehicle internal shoe drum brake of the duo-servo type having primary and secondary shoes located within a rotatable drum so that the primary shoe is carried round with the drum when the brake is applied, the slack adjuster assembly being located in a housing between adjacent ends of the shoes and including a thrust member which engages the ends of the shoes and transmits thrust on the primary shoe to the secondary shoe when the brake is applied. The adjuster assembly includes a sensing mechanism which senses relative movement between the thrust member and the housing and controls an energy-storing clutch mechanism which is connected to an adjuster and operates the adjuster to increase the effective length of the thrust member when the torque generated by the stored energy force is greater than the torque generated by the force applied to the thrust member from the shoe ends.

Abstract: A brake comprises an elongate friction pad engageable with a rotor surface, the friction pad being supported close to the rotor surface by a support. A connecting link connects the support to a fixed structure and transmits the braking drag forces to the fixed structure whilst permitting a degree of substantially friction-free movement of the body of friction material toward and away from the rotor surface.

Abstract: A hydraulic actuator for a vehicle brake system is provided with an auxiliary mechanical actuator e.g. a handbrake cam which is fitted to a first component (e.g. a first piston) of the hydraulic actuator and acts through an automatic slack adjuster on a second component (e.g. a second piston) of the hydraulic actuator. The adjuster comprises a rotatable push rod and a non-rotatable nut with a screw-thread connection therebetween. The rotatable push rod has a portion which is sealed to the first piston and upon which the mechanical actuator acts.

Abstract: The present specification describes and claims a friction pad assembly for use in a sliding caliper disc brake and a sliding caliper disc brake incorporating such an assembly. The friction pad assembly comprises a backing plate, a pad of friction material secured to the backing plate, and a wire spring attached to the backing plate and extending outwardly in two directions from its point of attachment to the backing plate. When the assembly is incorporated in a sliding caliper disc brake which comprises a torque member and caliper member, the wire spring engages the caliper member both pressing the friction pad assembly down onto guides in the torque member and biasing the torque member and caliper member apart to take up any clearance. Thus the possibility of the assembly rattling in the brake and the torque member and caliper member rattling together, is reduced.

Abstract: In a vehicle having a high center of gravity and having brakes on wheels on opposite sides operated by hydraulic actuators, either simultaneously for pure vehicle retardation or independently for steering fluid, fluid under pressure from a master cylinder assembly is supplied to all the hydraulic actuators through a inertia-controlled device so that the pressure of fluid from the master cylinder assembly is reduced at least when the brakes are applied simultaneously for pure vehicle retardation and the deceleration of the vehicle exceeds a predetermined value.

Abstract: In a wedge-type vehicle brake actuator with a cage assembly unattached to the wedge member the travel of the cage assembly is limited by an engagement with one follower member. With an assymetric cage assembly the assembly of the cage assembly into the housing is prevented by an engagement with a follower member when the cage assembly is assembled the wrong way.

Abstract: In a disc brake of the kind in which the clamping member straddling the disc consists of pressure plates located on opposite sides of the disc interconnected at their outermost ends by draw-bars, each draw bar is provided at at least one end with a screw-threaded portion which is screwed into an open-ended screw-threaded bore in a member and a releasable coupling is provided between the member and the one end of the draw bar.

Abstract: The invention concerns disc brakes of the kind in which only one of the friction elements is directly moved into engagement with the brake disc or other rotor, the other friction element being displaced as a result of reaction forces set up by such engagement and for this purpose being carried by a caliper member which is slidable responsive to such reaction forces. In a disc brake of this type in accordance with the present invention, the caliper is mounted for sliding movement on a first pin arranged between the caliper member and a fixed torque plate member adjoining the brake disc, rotation of the caliper member about said first pin being restrained by a second pin secured to one of said members in circumferentially spaced relation with said first pin.