Abstract: A wear adjuster for an internal shoe drum brake of the kind having a strut extending between one shoe and a handbrake lever pivoted on the other shoe includes a spacer between the strut and the one shoe, a screwing mechanism for adjusting the spacing effect of the spacer having an actuating mechanism responsive to service operation of the brake. The brake shoe pull-off spring serves also as a biassing spring for the actuating mechanism.

Abstract: A vehicle transmission clutch control including an electronic logic control which controls the transmission gear selection, a clutch position signal generator responsive to vehicle operating parameters to produce a command signal which operates a clutch control to govern the engagement of the clutch.A clutch disengagement control receives a gear change signal from the logic control and produces an output signal that can override the command signal to cause the control system to disengage the clutch. The output signal is caused to vary during a gear change and thereby alters the command signal and cause the clutch engagement to vary over the gear change period.

Abstract: A hydraulic master cylinder has pistons displaceable along the pivot axis of a brake pedal to apply the vehicle brakes. Motion between the pedal and the pistons is transmitted by balls located in a respective arcuate track formed partly in the pedal and partly in the respective piston. The master cylinder is particularly suitable for dual circuit brake systems. A master cylinder having a single piston is also disclosed.

Abstract: A vehicle electronic control system for a friction clutch having a clutch position signal generator which senses the vehicle operating conditions and produces a command signal which dictates the state of engagement of the clutch. A clutch actuator control is responsive to the command signal, and includes a transducer that produces a feedback signal indicative of clutch position which is fed into a comparator for comparison with the command signal. The feedback signal is modified by a signal derived from a wear compensator to alter the feedback signal as the clutch wears.

Abstract: A control system for a rotary transmission for controlling pressure during speed ratio changes. The system includes a pump for delivering fluid under pressure which fluid selectively engages speed ratio selectors to enable the drive to be transmitted through the transmission. The system also embodies a regulator for regulating the fluid pressure in response to a throttle controlled torque demand signal. The system also includes sensors arranged to provide a signal to indicate the state of a speed ratio as well as a command signal to effect a change in the speed ratio.

Abstract: An electronic control for a vehicle transmission having a clutch, the engagement of which is controlled in response to a clutch engagement signal. An electronic speed ratio logic for selection of the appropriate transmission gear ratio can produce a disengagement signal which overrides the engagement signal to cause disengagement of the clutch. A limiter is activated by a gear change signal from the logic to produce a limit signal which partially overrides the engagement signal to prevent full engagement of the clutch when the disengagement signal ceases, and the gear change signal is in operation.

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: An internal shoe drum brake having a pair of brake shoes mounted on a back plate with double ended expanders located one between each pair of adjacent ends of the shoes. The expander has a strut assembly slidable within itself so that when the expander is operated the strut assembly transmits braking loads from one shoe to the other so that the brake operates in a duo servo mode. With the expanders arranged to operate vertically the weight of the shoes and acts against the strut assembly. In order to support the upper brake shoe and prevent the shoes moving off-center a variable length support acts between the upper shoe and the wheel cylinder. The support has a spring therein so that the support can resiliently collapse when the sheos move during duo servo braking.

Abstract: This invention relates to clutch driven plates for motor vehicles and which comprise a hub having a circumferential flange, a co-axial friction facing carrier mounted on the hub and capable of rotational movement about the hub, and a co-axial intermediate drive means mounted on the hub for rotational movement relative to both the hub and facing carrier. Rotation of the facing carrier relative to the intermediate drive means is resisted by the larger springs and rotation of the intermediate drive means relative to the hub is resisted by softer springs. The construction of the plate is such that the drive means comprises two annular drive plates aranged one on each side of the hub flange and which are rotationally engaged with the hub by loosely engaging splines that allow for limited movement of the two plates around the hub.

Abstract: A vehicle automatic clutch control has an engine speed sensor that produces an electrical signal indicative of engine speed, an electrical reference signal generator that produces a reference signal, a throttle position sensor that produces a signal indicative of throttle opening. The throttle signal is summed with the reference signal to produce a modified reference signal which is then compared with the engine speed signal by a comparator that produces an error signal. The error signal is used for controlling a clutch actuator that operates the clutch to vary the engagement of the clutch to alter the engine speed and equalize the modified reference signal and engine speed signal and thus maintain a substantially constant engine speed until the clutch is fully engaged.

Abstract: An internal shoe drum brake automatic adjuster comprising a strut extending between one brake shoe and a wedge, mounted between the strut and an abutment on a second brake shoe. The wedge is spring loaded to increase the spacing between the adjacent end of the strut and the abutment. The wedge has serrations thereon that engage with a pawl on the second brake shoe so that the wedge can only move to increase said spacing and not in the reverse direction. There is also provided a brake in which the strut is engageable with a mechanical lever pivoted to the one brake shoe. The brake is de-adjusted by moving the lever so that it no longer contacts the strut.

Abstract: An electronic control system for a motor vehicle friction clutch and which has an electrical reference signal generator, an engine speed sensor and signal means, and a throttle position sensor which produces a signal indicative of throttle opening. The throttle signal is combined with the engine speed signal to form a modified engine speed signal and a comparator receives the modified engine speed signal and reference signal to produce an error signal derived from the two. A clutch position control is operated by the error signal to vary the state of engagement of the clutch to equalize the modified engine speed and reference signals.

Abstract: A hydraulic wheel cylinder assembly is particularly for use in a drum brake of the kind in which the wheel cylinder assembly is interposed between one pair or adjacent ends of a pair of brake shoes and a mechanical expander and fixed abutment is interposed between the other pair of adjacent ends of the shoes. The wheel cylinder assembly incorporates a pair of piston assemblies each including an adjustable variable length tappet assembly comprising rotatable and un-rotatable screw-threaded components. The rotatable screw-threaded component can move axially relative to the driven member of a one-way drive mechanism by compression of a spring when a flange on the driven member strikes the wheel cylinder body. This provides a self-centering force which prevents drag when the brake is installed with the shoes one above the other.

Abstract: An electronic control system for a motor vehicle friction clutch and which has an engine speed sensor, a reference signal generator, and a clutch actuator responsive to an error signal E derived from engine speed and reference signals V.sub.1 and V.sub.R respectively. The error signal E is fed into an integrator having two operation modes, dependent upon whether a capacitor in the integrator circuit bypassed by the error signal E or not. With the capacitor initially bypassed by the error signal E the integrator has unity gain, and with the capacitor subsequently placed in the error signal path the integrator has high gain. By having two response modes the time delay between the error signal E reaching its trigger point and the clutch actuator responding is greatly reduced.

Abstract: A control system is provided for a rotary transmission having a set gear trains and two clutches independently operable and providing alternative drive paths through the gear trains from an input to an output, alternate gear trains in the set being driven respectively through one and the other clutch. The control system includes sensor means to sense the operating state of the transmission, command means to command a change in the operating state of the transmission, control means responsive to the sensor means and the command means and including an array of electronic logic elements to control the transmission in a given series of discrete steps and operating means arranged to operate the transmission.

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: A clutch release mechanism for a pull type friction clutch for automobiles having a gearbox with a sleeve surrounding its input shaft. The mechanism comprises a release bearing assembly, a release fork and an automatically connectable and disconnectable coupling operably connecting the release fork to the bearing assembly. The coupling is caused to engage or disengage a shoulder on the bearing assembly depending upon the axial position of the gearbox sleeve relative to the coupling so that the coupling is automatically engaged or disengaged as the gearbox is respectively located in its operable position, or is withdrawn.

Abstract: A vehicle automatic clutch control comprising an engine speed sensor that produces a signal V.sub.1, an electrical reference signal generator that produces a signal V.sub.R and a comparator that processes the two signals V.sub.1 and V.sub.R to produce an error signal E. The error signal E is utilized for controlling a clutch actuator that operates the clutch to vary the state of engagement of the clutch to alter the engine speed and equalize the two signals V.sub.1 and V.sub.R and thus maintain a substantially constant engine speed until the clutch is fully engaged.

Abstract: An internal shoe drum brake automatic adjuster comprising a strut extending between one brake shoe and a wedge mounted between the strut and an abutment on the other brake shoe. The wedge is spring loaded to increase the spacing between the adjacent end of the strut and the abutment. The abutment is pivoted to the shoe and spring loaded against the wedge to maintain a clearance `S` between the abutment and a stop secured to the shoe.

Abstract: A release bearing assembly for a pull type clutch and which includes a stem attached to the stationary race of its bearing and which is accommodated between two arms of a release fork. The stem has a flange against which the arms abut during release of the clutch. The stem has a polygonal cross section, preferably hexagonal, providing pairs of diametrically opposed flats engagable with the fork arms, and the flange is also polygonal in shape, preferably hexagonal, and is angularly offset relative to the stem so that engagement of the arms with any pair of flats on the stem causes the stem to rotate on the bearing and thereby align the corners of the polygonal flange with the fork arms.