Abstract: The differential comprises a drive input element, two output cam members each rotatable about a common axis, each cam member having a single angular cam surface thereon of undulating form arranged such that the cam surfaces on the cam members converge towards each other and a plurality of cam followers. The followers have cam engaging end surfaces for imparting drive from the input element to the output cam members. Relative contro-rotation of the output cam members causes the cam followers to slide axially. The cam followers are elongate in direction of the common axis and are slidably supported throughout virtually their entire length by the drive input element. The followers may be arranged closely adjacent each other to provide a degree of mutual support.

Abstract: A motor vehicle having a transmission comprising a clutch (14), a clutch control (18, 20) and a change-speed gearbox (12). The gearbox (12) has a plurality of mutually exclusively engageable gear ratios any desired one of which can be engaged by a manually operated gear lever (16) which comprises a shaft (33) pivoted at (34) and a hand knob (42) on a tube (40) rockably pivoted in force relatively to the shaft (33), a signal is sent to the clutch control (18, 20) causing automatic disengagement of the clutch (14). Further manual force on the tube (40) pivots the shaft (33) in direction (A) or (B) to the opposite side of a gear shift pattern. The clutch control (18, 20) receives a signal (54') that a new gear ratio has been engaged and automatically reengages the clutch (14).

Abstract: The engine output torque of a motor vehicle is a function of the extent to which the throttle valve is open, the further the valve is open, the greater the throttle angle and the greater the output torque. Microprocessor based clutch control is provided to measure the throttle angle, determine the output torque, and automatically engage and disengage the clutch with respect to time. The clutch control also allows manual gear operation and clutch slip control.

Abstract: The transmission includes a rotary shaft for transmitting drive to driving wheels of the vehicle, a fixed gearbox casing and a hill holder between the shaft and the gearbox casing. The hill holder, when operative, inhibits reverse movement of the vehicle and includes in series a sprag clutch and a multiplate brake. Fluid is supplied from a fluid operable control system for operating the brake and controls the rate of engagement of the brake.

Abstract: A method of shipping and installing a hydraulic system such as a motor vehicle clutch hydraulic release mechanism comprising a driver-operable hydraulic master cylinder, a hydraulic slave cylinder and a conduit connecting the outlet of the master cylinder to the inlet of the slave cylinder. Prior to shipment and installation on a motor vehicle, the hydraulic system is filled with hydraulic fluid and bled or purged of atmospheric air, and installation on a motor vehicle is therefore greatly simplified as the requirement of filling with hydraulic fluid and bleeding or purging the hydraulic system after installation is entirely eliminated.

Abstract: An electronic clutch control system for a friction clutch for starting a vehicle from rest has a clutch position control loop in which the actual clutch position feed-back signal is modified to compensate for changes in clutch characteristic. An engine speed control loop: clutch, engine, engine speed sensor, processed signals, clutch actuator control includes a switchable integrator. A wear compensation signal is added to the clutch position feed-back signal which is then subject to gain control in a gain control device in response to changes in slope of the torque-capacity/clutch position characteristic.

Abstract: Concentric piston and cylinder components of a hydraulic slave cylinder used with a clutch release bearing have their axial movement under a biassing spring limited by latch means in the form of flanges. The flanges each have a radial face and a chamfered face, and one flange is radially deformable, being on a slotted cylindrical extension. The radially deformable flange allows the cylinder to be rapidly assembled without the need for assembly of a separate retaining device.

Abstract: Fluid pressure for engagement of a clutch is controlled by a valve alternating between supply and drain conditions in response to a high frequency electrical square wave signal. The valve produces a low flow pilot pressure signal which controls clutch engagement pressure through a valve incorporating a piston which allows clutch engagement pressure to drain whenever that pressure exceeds pilot pressure.

Abstract: Friction clutch release apparatus for a motor vehicle comprises a driver-operable master cylinder, a slave cylinder and a conduit which connects the master outlet to the slave cylinder inlet. A liquid reservoir communicates with the bore of the master cylinder between the piston and the outlet when the piston is retracted and has a vent port. The apparatus is assembled, filled with liquid and bled before being installed on the motor vehicle. The vent port may be closed temporarily for convenience of transport and storage after the apparatus is bled, for example by use of a suitable removable closure device which would be removed after installation of the apparatus on the motor vehicle, or may include a movable wall within the reservoir chamber by which liquid within the chamber is separated from that part of the chamber with which the vent port communicates.

Abstract: An air/hydraulic servomotor unit for providing power assistance for a clutch hydraulic operating system and comprising a compressed air cylinder, a hydraulic slave cylinder, a load proportioning means that determines what ratio of the unit output is derived from the hydraulic and air cylinders, and a clutch operating member.The hydraulic slave cylinder is secured to one end of the air cylinder housing and has a piston which passes through the air cylinder piston so that both pistons can act against the proportioning means. All the unit output loads pass through the proportioning means prior to being transmitted to the operating member.

Abstract: A fluid pressure servo motor comprises a body having two operatively independent fluid chambers each chamber having therein a piston means movable in response to a fluid pressure differential so as to alter in use a two condition device from one to the other of said two conditions. The two piston means each have a lost motion means connection with the device to allow idle return of the pistons on cessation of the pressure differential. The two chambers and their respective pistons are co-axial and the pistons work in opposition to each other, one piston being fixed to a stirrup which bridges the other piston and acts in use against the two condition device, while allowing said other piston to move independently of the stirrup. Also disclosed is a vehicle door locking system incorporating servo motors as described.

Abstract: This invention relates to a self-aligning clutch release bearing assembly comprising a rolling element bearing having a rotary race which in use engages with a clutch member, and a non-rotary race mounted on a support for transmission of a clutch release load. The non-rotary race is relatively movable on the support transversely to the rotary axis of the bearing assembly to permit in use self-alignment of the rotary axis of the bearing with rotary axis of the clutch member. This movement is controlled by a layer of viscous material interposed between the support and the non-rotary race. The viscous material exhibits some resilience and up to a given value resistance to plastic flow so that the material locates the non-rotary race but allows it to move to achieve self-alignment on operation of the clutch in use.

Abstract: A ratarder for a power transmission shaft comprises a liquid immersed coupling between the shaft and a drag member, the drag member being normally entrained to rotate with the shaft by viscous drag in the coupling. A dry brake mechanism, having a frictional drag greater than that of the coupling, is provided to restrain the drag member for relative movement to take place in the coupling. In the embodiments shown, the coupling comprises a friction disc pack alternately connected to the shaft and the drag member, the brake mechanism firstly restraining the drag member and subsequently shifting it axially to engage the friction disc pack.The coupling is suitable for use in heavy motor vehicle transmission systems.

Abstract: A master cylinder and brake valve assembly for operating the clutch and clutch brake of a heavy road vehicle is arranged such that up to a first given displacement of the master cylinder piston the clutch release mechanism only is connected to the master cylinder and, above a second further given displacement of the piston, the brake actuator only is connected to the master cylinder, there being a step change in thrust applied to the piston between the given displacements.In a modification, above a third further given displacement of the piston, the brake actuator is reisolated from the master cylinder.

Abstract: This invention relates to an air powered braking system for a vehicle. The air pressure in the front and rear brake systems is regulated by a respective one of a pair of air pressure valves. The air valves are hydraulically controlled and each valve (16) and (26) is independently connected to a driver operable hydraulic master cylinder so that the air pressure in each of the front or rear systems is proportional to the hydraulic pressure generated at the master cylinder (11). A hydraulic reducing valve is interposed in the hydraulic circuit between the master cylinder and the rear brake system air valve and operation of the reducing valve reduces the hydraulic pressure to that air valve and hence reduces the air pressure to the rear brakes relative to the air pressure to the front brakes.

Abstract: A twin-piston (e.g. tandem) master cylinder is provided for a split braking system having disc brakes on some wheels of a vehicle and drum brakes on others. A delay valve is incorporated in the master cylinder for the supply to the disc brakes, the delay valve having a valve member controlled by one of the master cylinder pistons to initially shut-off the supply of fluid to the disc brakes after the piston has moved a short distance. A plunger moves against a control spring to re-open the supply to the disc brakes above a predetermined pressure.

Abstract: This invention relates to a self-aligning clutch release bearing assembly comprising a rolling element bearing having a rotary race which in use engages with a clutch member, and a non-rotary race mounted on a support for transmission of a clutch release load. The non-rotary race is relatively movable on the support transversely to the rotary axis of the bearing assembly to permit in use self-alignment of the rotary axis of the bearing with rotary axis of the clutch member. This movement is controlled by a layer of viscous material interposed between the support and the non-rotary race. The viscous material exhibits some resilience and up to a given value resistance to plastic flow so that the material locates the non-rotary race but allows it to move to achieve self-alignment on operation of the clutch in use.

Abstract: A tandem master cylinder for a vehicle split hydraulic braking system which has disc brakes in one half of the system and drum brakes in the other. One of the pistons in the master cylinder is prevented from developing a substantial pressure until a predetermined pressure has been developed by the other piston by virtue of a quantity of fluid trapped in a control chamber by a control piston. First and second valve means control the pressure in the control chamber. The valve means include a plunger which initially moves against a first control spring to allow a valve member to seat and trap the fluid in the control chamber and subsequently moves away from the valve member under an increased pressure in the control chamber against a second control spring to release the trapped fluid.

Abstract: A release bearing assembly for a vehicle clutch comprising inner and outer relatively slidable sleeves located around the gearbox shaft. The inner sleeve is coupled to the clutch operating lever and the outer sleeve to the release fork of the clutch. The outer sleeve is in a predetermined position when the clutch is engaged and is moved axially away from that position when the clutch is released. An annular member threadably engages the exterior of the inner sleeve and abutment means act on the annular member during clutch release so that the two sleeves move together. Clamping means hold the annular member against rotation during clutch release. Release means release the clamping means when the clutch is re-engaged so that the annular member can rotate about the inner sleeve to allow the inner sleeve to move axially relative to the outer sleeve when it is at the predetermined position to compensate for any wear of the clutch.

Abstract: A disc brake is of the kind which has an actuator on one side of the disc only, the brake pad on the other side of the disc to the actuator being applied to the disc by the actuator through a yoke of closed loop form. The yoke is constructed with two overlapping sheet metal pressings which are generally flat except where they pass over the periphery of the disc where one pressing is domed away from the other to form a box-section.