Abstract: In a master cylinder assembly of the kind in which transfer chambers in pedal-operated master cylinders are connected by a transfer passage, each master cylinder has a transfer valve which is normally open and which is movable into a closed position to isolate the transfer chamber of that master cylinder from a reservoir in response to an increase in pressure in the transfer chamber when the other master cylinder is operated on its own.

Abstract: In an anti-lock brake control system for a vehicle with braked wheels, a brake pressure release pulse is produced in a manner dependent on wheel deceleration and is processed so that it cannot exceed a preset maximum length and is spaced from any other brake pressure release pulses by a preset inhibit period so that brake pressure release pulses cannot be produced above a certain maximum repetition frequency. A deceleration sensing switch produces an output pulse, and a pulse circuit is triggered by the leading edge of the output pulse to commence said brake pressure release pulse, and is reset by the lagging edge of said output pulse to terminate said brake pressure release pulse. A pulse timing circuit is also triggered by the leading edge of said output pulse and operates to terminate said brake pressure release pulse after said predetermined maximum duration if it has not been terminated already.

Abstract: A pendulum responsive to excessive deceleration operates a valve which creates a pressure differential across a pressure responsive member to close an inlet valve to the brake chamber and expand an outlet chamber to thereby reduce the rear brake pressure. The invention provides retaining mechanism for preventing the pendulum from swinging during non-braking periods and for returning the pendulum to its inoperative position upon a reduction of inlet pressure. A piston responsive to pressure at the inlet moves the retaining mechanism to a position wherein the inertia member is free to swing during normal brake applications.

Abstract: A disc brake having a caliper member which straddles a minor portion of the periphery of a rotatable disc and which is displaceable with respect to a fixed torque-taking member of the brake for applying friction elements to opposite sides of the disc. The caliper member is slidably mounted on the torque member by means of a pin secured to one of the members and slidable in a recess in the other of the members. The torque member also slidably carries the friction elements and restrains the elements from movement radially of the disc. In order to prevent the caliper member from pivoting about the axis of the pin, the caliper member is held by at least one of the friction elements, this being effected by an interengaging projection and recess, the recess opening in a generally radial direction relative to the axis of the pin.

Abstract: In a control valve assembly for vehicle hydraulic braking systems pressurization of a distributor chamber in a housing is controlled by a valve operating mechanism. The valve operating mechanism comprises a piston working in the distributor chamber, a recuperation port in the wall of the housing for connection to a reservoir for fluid and communicating with the chamber on one side of the piston, an axial bore through the piston providing communication between the recuperation port and an inlet passage for connection to a source of high pressure fluid, an axially movable valve member for alternate engagement with first and second axially spaced seatings, the first seating comprising a seating surrounding the opening in the piston and the second seating leading to the inlet passage, and a spring for urging the valve member normally into engagement with the second seating with the valve member spaced from the first seating.

Abstract: An anti-lock brake control system for vehicles with braked wheels comprising a wheel speed sensor for producing a signal proportional to wheel speed; a first switch having an input connected to the sensor to receive the wheel speed signal and being adapted to respond to the rate of change of said signal so as to produce a first control pulse to effect brake pressure release while a preset first wheel deceleration threshold is exceeded; a second switch that is triggered under the control of the first control pulse and which, when triggered, initiates a second control pulse to effect brake pressure release; and a charge storage device that receives the wheel speed signal so that it accumulates a charge dependent on the dip in wheel speed and discharges in response to wheel speed recovery following said dip in wheel speed, and which is associated with the first and second switches so that it discharges in a predetermined manner after the first control pulse terminates and terminates the second control pulse when

Abstract: In an hydraulic power system for operating a vehicle levelling system and braking system, an accumulator supplies both the levelling system and the braking system. The accumulator is connected indirectly to the braking system through a pressure limiting device, which disconnects the braking system from the accumulator when a predetermined pressure is reached.

Abstract: An hydro-pneumatic suspension assembly for vehicles comprises a pressure chamber in a combination with an hydraulic suspension unit of the self-levelling type. The unit incorporates a spool valve for maintaining the length of the unit at a predetermined value irrespective of the load. The spool valve is responsive to the position of a piston rod which carries the piston of the unit, and a damper, comprising a restricted passage, is incorporated to delay the response of the spool valve to movement of an assembly comprising the piston and the piston rod.

Abstract: In a fluid-pressure operated anti-skid braking system operation of a brake applying relay valve is controlled by application pressure in an application chamber. A memory chamber is connected to the application chamber through a one-way valve and a restrictor permits pressure in the memory chamber to decay into the application chamber when the pressure in the application chamber reduces at a skid point. Application pressure is supplied to the application chamber through a normally open latch valve. Re-application of the brakes following a skid is controlled by closure of the latch valve which permits only a restricted flow of application pressure into the application chamber. This is sufficient to re-apply the brakes rapidly in a first stage until the pressure in the application chamber becomes equal to that of the decayed pressure in the memory chamber.

Abstract: A disc brake assembly includes one or more rotatable friction discs which are slidably keyed to a second portion of a two part shaft assembly and the second portion surrounds and is rotatable relative to the first portion which transmits drive directly to a wheel and drives the second portion through a reduction gear train so that the second portion can rotate at a greater speed than the first.

Abstract: An anti-skid brake control system has a brake pressure control unit for producing a release signal to trigger the release of brake pressure and a subsequent re-apply signal to trigger the re-application of brake pressure in successive brake pressure release/re-apply cycles; and a change-over control unit for producing a change-over signal to trigger a change from a first, rapid re-apply stage, in which brake pressure is re-applied rapidly, to a second, slow re-apply stage in which brake pressure is re-applied slowly, during the re-apply period of each cycle; the change-over control unit including a storing device responsive to the duration of the re-apply period in successive cycles so that the change-over point in each cycle is controlled in a manner dependent on the duration of the re-apply period in the preceding cycle, whereby the duration of the re-apply period is dynamically adjusted to assume a preset value.

Abstract: In a two-pedal hydraulic braking system for vehicles the pedals are operable independently or simultaneously to apply two sets of brakes and both pedals actuate a common master cylinder to apply fluid under pressure to the brakes. Two normally closed selector valves are operable independently to direct the fluid to either of the sets of brakes when one pedal is operated, and the valves are operable simultaneously to direct the fluid to both sets when the pedals are operated simultaneously. Each valve is urged directly into its closed position by its respective pedal, and each pedal in turn is urged by a return spring into a retracted position in which the valve which it operates is closed.

Abstract: A brake control unit for a vehicle hydraulic braking system is adapted for incorporation between the master cylinder and the rear wheel brakes, with the front wheel brakes being applied by pressure from the master cylinder. The control unit incorporates an outlet connected to the rear wheel brakes, and an inertia-controlled valve, which closes when the deceleration of the vehicle is excessive, to ensure by means of a metering valve that any subsequent increase in pressure applied at the outlet occurs at a rate less than the rate at which the master cylinder pressure increases. The unit also incorporates an override responsive to front wheel brake pressure which is operative, following closure of the inertia-controlled valve and reduction in front wheel brake pressure, to override the effect of the inertia-controlled valve.

Abstract: In an hydraulic system an unloader valve is located in a line between a pump and an hydraulic accumulator. The unloader valve is operative to prevent the accumulator from being overcharged and to allow the pump to re-charge the accumulator should the pressure stored therein fall below a desired minimum value. The unloader valve incorporates a control valve comprising a spool, and a pressure responsive slave which is operated by fluid pressure under the control of the control valve. Two springs bias the spool into a first position in which pump pressure can be supplied to the accumulator, and the second spring is inoperative when the spool is moved into a second position in which fluid pressure from the accumulator can act on the sleeve to reduce the pump pressure to that of the tank for the pump.

Abstract: In a control valve assembly for a vehicle dual hydraulic braking system separate brake-applying valves in a common body are operable independently or simultaneously to cause hydraulic fluid from a distributor chamber to be supplied to one or both of a pair of outlets for connection to brakes on wheels on opposite sides of the vehicle. Each brake-applying valve comprises a valve member which is urged into engagement with a seating surrounding a respective outlet by means of a spring. An operating member for moving the valve member away from the seating in a brake applying direction is coupled to a respective brake pedal, and the operating member is also coupled to the valve member through a lost-motion connection.

Abstract: In a disc assembly for a vehicle disc brake, the assembly comprises a rotor, with brake rings secured to one or both of a pair of opposite faces of the rotor by bolts passing through clearance openings in the rotor. Each brake ring comprises at least two segments, with clearances provided between adjacent radial ends of the segments. The segments are coupled by pivotal links, and a single pivotal connection is provided between each segment and the rotor. The pivotal connection is located to one side of a radius of the disc bisecting the segment, and the segments, links, and pivotal connections are constructed and arranged to maintain the disc assembly in balance irrespective of centrifugal, shock, or expansive forces.

Abstract: In a fluid-pressure operated anti-skid braking system operation of a control valve is controlled by a force of which the magnitude is determined by utilization of the pressure in a memory chamber defined between a pair of relatively movable spaced pistons. The piston carries a head which forms part of the valve, and the other piston is exposed to an operator-controlled pressure from an inlet passage.

Abstract: A control valve assembly for a vehicle dual hydraulic braking system in which hydraulic fluid from a distributor chamber can be supplied to one or both of a pair of outlets for connection to brakes on opposite sides of a vehicle. The assembly incorporates a pressure control valve operable to supply fluid under pressure to the chamber from an outlet for connection to a pressure source, irrespective of whether one or both of two separate brake-applying valves are to be operated, and a one-way valve is located on the upstream side of the pressure control valve to prevent flow in a reverse direction. A back-up piston works in a bore in communication with the chamber, and is provided to pressurize fluid in the chamber after an exhaust valve has closed and a pressure control valve has opened.

Abstract: In a disc brake of the slidable reaction type in which an hydraulic actuator is located in a stationary member, a clamp member is guided for movement relative to the stationary member in a direction substantially parallel to the axis of the disc by means of a pin which is connected to one of the members and is slidably mounted in the other member.

Abstract: In a disc brake such as a sliding caliper disc brake, the caliper is mounted for movement with respect to a torque plate by pin assemblies extending into aligned openings in the caliper and torque plate. The pin assemblies are of multi-part construction, parts of the pin assemblies which provide for movement between the caliper and torque plate being able to remain undisturbed when the caliper is removed from the torque plate.Another feature is that the openings in the caliper or the torque plate are oversize, so that the pin assemblies are received as a free fit, and the pin assemblies are clamped in the oversize openings by interengagement of screw threaded portions. Sliding surfaces are provided either directly by the shanks of pins or by separate bushes which may be resilient.The construction is such that the pin assemblies are relieved of clamping forces and drag forces when the brake is actuated.