Lucas Industries Public Limited Company

Girling Limited

Lucas Industries Limited

Anthony W Harrison

Philip A Taft

Alfred W Thomas

Brian Robert Allen

Glyn P Farr

Ivan Mortimer

John P Bayliss

Peter W Brown

Robert J Goudie

In a power assistance system for a vehicle steering mechanism fluid pressure providing the assistance is supplied from a pump driven intermittently by an infinitely-variable electric motor. For a rack and pinion mechanism fluid pressure chambers are formed by sealing boots at each end of the rack, and are connected through the pump, which is operative to create a pressure differential between the chambers, and thus across the rack to provide power assistance. The electric motor is energized as required to drive the pump in the appropriate direction, and when the motor and pump are inoperative fluid is allowed to flow freely between the chambers to accommodate fluid displacement as a result of unassisted operation of the steering. The pump is preferably a turbine pump, which allows fluid flow when inoperative. The system provides power assistance efficiently, and relatively cheaply.

Power assistance for vehicle steering mechanisms

An hydraulic braking system includes a primary pressure source connected to a brake actuator and operable by a force input device, a fluid displacer actuated by an electrical stepper motor operated by a controller in response to action of the force input device, as sensed by a sensor, whereby fluid displaced from the displacer is added to that displaced from the primary pressure source for application to the brake actuator. By suitable programming of the controller, servo-assistance and/or quick-fill modes can be produced by the displacer and wheel-slip correction and anti-skid facility can be provided.

Hydraulic braking system

A braking system for a vehicle has a stepper motor which controls the application of friction elements to a rotating part such as a brake drum. A control circuit controls the motor so that an output member is positioned by the motor in accordance with a variable demand signal. In one application, the control circuit receives a brake pressure signal from a transducer and controls the motor so as to compensate automatically for brake wear. In another application, the motor controls a debooster of an antilock brake system. The system also may include means for operating a parking brake.

Vehicle braking system

An internal shoe drum brake has a body (1) carrying a plurality of circumferentially spaced friction elements (2) movable into engagement with a rotatable drum (3) by a hydraulic system including an actuator (5) having a pressure-applying cylinder (2) in which a pressure-generating piston (21) is driven by an electrical stepper motor (28), slave cylinders (4) which actuate the friction elements, and internal ducts (7, 8) for transmitting pressure from piston (21) to slave cylinders (4).

Brake

A rotary electric drive device for use in a vehicle anti-skid braking system has a rotary armature supported by a thrust race in relation to a housing. One part of the thrust race has external teeth for co-action with a pawl which is disengaged from the teeth for one direction of rotation of the armature but engages the teeth during rotation in the other direction to lock the race part to the housing. When this happens, slipping occurs between opposed contiguous faces of the armature and part respectively in order to dissipate some of the rotational energy of the armature when the drive device is de-energized.

Rotary electric drive device for anti-skid braking system

A combined brake release solenoid valve and motor driven debooster has a plunger forming part of the debooster, which, on brake re-application is moved to a flow-restricting position in which there is only a restricted connection between the brake master cylinder and the slave cylinder, so as to avoid over-rapid brake re-application. In one embodiment, the plunger is positioned to provide a stop for the solenoid valve. In another embodiment, the plunger coacts with a separate valve seat.

Wheel skid correction device for vehicle braking system

A caliper is mounted on an axle casing of a rail vehicle by a first bracket and by a second bracket positioned between the disc and the first bracket. One of the brackets is detachably mounted on the casing and is removable to permit the caliper to be removed by movement in a generally axial direction. To permit this to happen the caliper and the other detachable bracket both lie outside the projected peripheral edge of a flange on the axle on which a wheel is mounted.

Disc brakes in vehicles

An electrical solenoid valve has a coil and a movable armature. A first valve element is subject to pressure from an inlet and a second valve element is operated by the armature, when the coil is energized, to close a port in the valve element and so isolate the inlet from a pressure fluid outlet to a brake. The valve element is displaceable under the effect of a pressure differential across it as a result of closing the port, the force derived from the then predominant inlet pressure being transmitted by the second valve element to load a spring device connected to the armature. Such spring loading increases the force tending to release the armature and leads to rapid opening of the port (18), when required.

Electrically operated solenoid valve

A brake adjuster wherein a thrust block is axially slidable in a cylinder bore and rotatably connected to one of two screw threaded adjuster members which are themselves interconnected by a self-sustaining thread. In use a power spring acts on the thrust block to move it axially within the cylinder bore to apply pressure to a friction pad via the adjuster members. The brake may be released by applying hydraulic pressure to the thrust block, at which time one adjuster member is rotated via a clutch, when a predetermined clearance has been taken up, relative to the other to adjust for pad wear. No relative adjustment occurs during application of the brake under the action of the power spring.

Brake adjusters

The present specification discloses an actuator for use in a vehicle brake. The actuator incorporates an adjuster which automatically provides an adjustment to take account of pad lining wear, to thus maintain a substantially constant brake clearance. The brake actuator of the present invention comprises a hollow piston which is axially slidably located in a cylinder with an elongate shaft extending axially through said cylinder and said hollow piston. Said shaft is fixed in a position within the cylinder and carries a spiral thread and axially extending splines. An adjuster nut is rotatably mounted on said spiral thread and is engaged by detent means mounted on said axial splines. Said detent means are spring biassed against the adjuster nut by a spring which engages said piston. The present invention thus provides a brake actuator with an adjuster nut located within the actuator piston, wherein the piston is positively returned after brake release and vibration cannot produce any unrequired adjustment of the adjuster nut.

Brake actuators

The present specification discloses a brake actuation system for a vehicle, which is applicable to both hydraulically or pneumatically operated/spring released brakes and spring operated/hydraulically or pneumatically released brakes. With such brakes it is often necessary to have secondary means for brake operation or release. Such braking systems thus have primary and secondary means for brake operation or release. The present invention provides a fail-safe system which can provide at least an indication of impending failure. The brake actuation system of the present invention comprises a cylinder within which two axially aligned pistons are axially slidable, the space between one end of the cylinder and one piston being connected to a primary power system and the space between said pistons being connected to a secondary power system. When such an actuation system is used in a spring operated/hydraulically released braking system, the primary power system of the present invention is the primary brake release and the secondary power system is a secondary or emergency release which may constitute a handpump. By providing suitable flow detection means in the primary and secondary power systems, leakage past piston seals can be monitored and detected before the seal failure is sufficient to dangerously affect brake performance.

Brake actuation systems for vehicles

A controller for controlling the increase in fluid brake pressure as a brake is applied irrespective of how rapidly the operator applies the brakes. The controller includes a valve between inlet and outlet ports in a valve body, the valve having opposing faces subjected respectively to pressure at the outlet and pressure in a volume chamber between the valve and a spring loaded piston and connected to the outlet through a restricted orifice. The valve seeks an equilibrium position wherein the rate of rise in pressure at the outlet is controlled and the deceleration of the vehicle is controlled even when the operator applies the brakes at an excessive rate.

Railway deceleration controller for brake

A clutch servo for a vehicle cable-operated clutch system has a housing, an input member to which an input force is applied by the cable which has an inner cable and an outer sheath, an output member connected to a clutch, and a movable wall for augmenting the output force which acts through the output member. The movable wall is operated by a fluid pressure chamber, pressurization of which is controlled by a valve in response to the input force. In one construction the inner cable is movable relative to the movable wall and a locking device is incorporated to lock the inner cable and the movable wall against relative movement when the movable wall is not in its retracted position. This ensures that the servo is not affected by adjustment of the cable to compensate for clutch lining wear when this adjustment is performed between the servo and the pedal. In another construction the servo includes an adjuster mechanism in the form of a locking mechanism between the housing and an end of the sheath, which is inoperative when the inner cable is retracted to allow relative movement between the end and the housing, and which operates when the inner cable moves from its retracted position to lock the sheath and the housing against movement. A valve actuating mechanism in the form of a lever is also incorporated to transmit the input force from the cable to the valve operation of which is controlled by the input force and an opposing force in at least one spring.

Clutch servos

The friction pad assembly of the present invention has a generally rectangular back plate with two retaining tabs projecting from opposite side edge regions, at an angle to the general plane of the back plate. The support or shoe is also generally rectangular and has a recess formed in each of two opposing side edges, the retaining tabs on the back plate engaging snugly into these recesses. The support has a further H-shaped recess in its front face within which an elongate spring plate is secured so as to project beyond opposing ends of said support. Thus, in use, the friction pad assembly can be quickly and simply mounted on the support and when the brake is operated the end region of the spring plate through which pad drag is passed to pad guides, flexes to thus allow for unhindered axial movement of the friction pad assembly and support.

Friction pad assemblies and their support

The present specification discloses a brake actuator incorporating a mechanically operated adjuster, the adjuster compensating for friction pad wear. The brake actuator comprises two adjuster members interconnected by a self-sustaining thread and located between a friction pad and an actuation member, the actuation member being biassed by a main spring to a brakes-on position with at least one hollow piston being displaceable under hydraulic pressure to compress the main spring and move the actuation member to a brakes-off positon, a second piston being carried within the hollow piston and being carried within the hollow piston and being axially displaceable therein under the hydraulic pressure and against a further spring, to cause interengaging clutch elements to rotate one adjuster member relative to the other adjuster member, a stop being arranged to limit the available movement of the clutch elements. The present invention thus provides a mechanically operated adjuster which avoids the inherent disadvantages of hydraulic operation.

Growing community of inventors

Birmingham, United Kingdom

Anthony W Harrison