Girling Limited

David Anthony Harries

Brian Ingram

Ivan Mortimer

Frederick James Knight

Ramamurthy Natarajan

A drum brake is disclosed in which at least two, and preferably four, friction pad assemblies are symmetrically arranged with respect to the drum. The pad assemblies are slidably guided for movement towards and away from the drum in a substantially radial direction on drag-taking abutments in a relatively stationary drag-taking member, and the pad assemblies are applied to the drum by levers upon which actuators act.

Drum brakes for vehicles

A power operated actuator assembly incorporates a stop mechanism for opposing movement of an actuating member if a booster fluid supply is operative. The stop mechanism comprises a chamber which is supplied with a metered proportion of pressurized fluid when the actuating member is moved such that the greater the force on the actuating member, the greater will be the magnitude of the force due to the pressurized fluid opposing movement of the actuating member.

Actuator assemblies for vehicle hydraulic braking systems

In a fluid pressure-operated anti-skid braking system for vehicles, operating fluid from a supply is supplied to the wheel brake through a fluid-flow control valve interposed between the supply and the brake. A deceleration responsive device responsive to a skid signal is incorporated for operating the control valve to relieve the brake pressure of the fluid supplied to the brake when the deceleration of the wheel is excessive and exceeds a pre-determined value. A memory for storing a memory pressure dependant on the brake pressure at a skid is incorporated, and the memory pressure operates the control valve directly during a first stage of brake re-application, and provides a changeover point between first and second stages of brake re-application. The second stage comprises continued re-application but at a reduced rate of pressure increase.

Anti-skid vehicle braking systems

A booster operated master cylinder piston for use in an anti-skid braking system includes a modulator piston located between the master cylinder piston and the booster valve assembly. In the event of a skid the pressure of booster fluid acting on the modulator piston is equalized across the modulator piston.

Master cylinder assemblies

In a power control valve assembly in which the position of an inlet valve member relative to its seat is controlled by a control rod extending through a passage terminating in the seat, an end portion of the control rod has a profile which gives a variable throttling of flow through the passage in dependence upon the axial position of the control rod. In the valve described the end portion of the rod has an end part of constant diameter connected to a further part of reduced diameter by a sloping shoulder. Two such valve assemblies are shown arranged in parallel and operated through a single resilient block and a balance beam.

Fluid valve assemblies

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.

Modulator assemblies for vehicle hydraulic braking systems

In a control valve assembly for a vehicle hydraulic braking system a differential piston works in a stepped bore in the housing of the valve and is exposed at its end of greater area to an inlet port and at its end of smaller area to a chamber in the valve, the inlet port communicating at all times with the chamber through a restricted passage in the piston, and the chamber communicating with a further chamber in which a valve is located at least when the valve is in a first position in which the inlet port is in communication through the chambers with an outlet port for connection to the wheel brake.

Control valve assemblies for vehicle anti-skid braking systems

In a master cylinder assembly a booster valve assembly is adapted to control two separate supplies of booster fluid, and each supply is capable of advancing a modulator piston independently to operate a master cylinder.

In a pneumatically-operable actuator assembly for a vehicle hydraulic braking system a control valve assembly comprises a first valve responsive to a signal of deceleration for controlling communication between an inlet passage for connection to a supply of air under pressure and a modulator chamber through a supply chamber, and a second valve downstream of the first valve for controlling communication between the modulator chamber and an exhaust passage and responsive to pressure in the supply chamber, the first valve being substantially smaller than the second valve whereby the pressure in the modulator chamber can be reduced rapidly in response to a relatively small reduction in the pressure in the supply chamber.

In a vehicle hydraulic braking system the supply of fluid from an hydraulic master cylinder to the slave cylinder of a wheel brake is controlled by an actuator assembly which includes a modulator assembly for controlling the supply to the slave cylinder in accordance with the deceleration of a wheel operated by the slave cylinder, and both the master cylinder and the actuator assembly are actuated in response to separate supplies of the same fluid pressure medium.

Actuator assemblies for hydraulic vehicle braking system

A master cylinder assembly for a vehicle hydraulic braking system comprises a pedal-operated valve assembly for controlling a supply of fluid under pressure to a power chamber in a housing on the opposite side of a piston to a pressure space which has an outlet for connection to a wheel brake, and a second piston is adapted to be applied by the pedal to generate fluid pressure in said pressure space.

Master cylinder assemblies for vehicle hydraulic braking systems

A booster operated master cylinder piston for use in an anti-skid braking system includes a modulator piston located between the master cylinder piston and the booster valve assembly. In the event of a skid the pressure of booster fluid acting on the modulator piston is relieved.

An actuator assembly for a vehicle brake includes three axially aligned pistons, a first actuating piston for applying the brake hydraulically during normal service braking; a modulator piston movable for anti-skid purposes between a first position in which an inlet valve controlling the supply of fluid to the first actuating piston is open, and a second position in which the inlet valve is closed; and a second actuating piston resiliently urged through the modulator piston to engage the first actuating piston to apply the brake for parking purposes but normally held out of engagement by fluid pressure in a chamber formed between the modulator piston and the second actuating piston, the pressure in the chamber also holding the modulator piston in the first position.

Actuator assemblies for vehicle brakes

An anti-skid braking system for vehicles includes a connection between a master cylinder and each wheel brake by-passing a modulator for modulating the braking pressure in the event of a skid. Each by-pass connection is controlled by a valve and all the by-pass valves are normally maintained closed by a single piston responsive to the same fluid pressure which operates the modulator. The system may also include valves for isolating the modulator from the wheel brakes when the by-pass valves open.

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Solihull, United Kingdom

David Anthony Harries