Abstract: The present specification provides a caliper for use in a disc brake. The caliper has at least two body sections which are clamped together by one or more bolts, each bolt having a bore extending axially therethrough, the bores acting as pin guides for the pins secured to the torque taking member, in the complete brake. Thus only a pair of holes are required to be formed in the caliper body sections, improving the strength and rigidity of the caliper and keeping manufacturing costs to a minimum.

Abstract: In a high pressure hydraulic system a source supplies pressurized fluid to a slave unit through a control valve operative to maintain the slave unit in a desired condition. Leakage from the slave unit past the control valve when the source is inoperative is undesirable, but it is difficult to provide durable leakproof seals and to minimize valve operating forces at high fluid pressures. The control valve therefore comprises two solenoid-operated valves oppositely acting and arranged in series between the source and the slave unit, each valve being closed to prevent flow through the valve in a direction from the other valve and opened to permit flow in both directions, under the control of a solenoid and the pressure differential acting across the valve, a seating portion on a first valve is of elastomeric material to provide a leakproof seal when that valve is closed.

Abstract: A starting aid for an internal combustion engine comprises a tubular extension in the end of which is wound an electric heating element. Surrounding the extension is a tubular member which ever at least a substantial portion of its length is mounted on spaced relationship to the extension. The member is formed from heat resistant material and acts to minimize the temperature attained by the extension when the aid is in use.

Abstract: A fuel injection pumping apparatus for supplying fuel to an engine is of the rotary distributor type and has an annular cam ring having cam lobes for imparting inward movement to a pumping plunger. The trailing flanks of the cam lobes define metering portions which are less steep than those of known pumps so as to extend the time during which the outward movement of the plunger is controlled by the cam lobes. In addition the apparatus includes a sleeve slidable in the distributor member of the apparatus and this incorporates a shaped recess which communicates with a source of fuel. The bore containing the plunger communicates with an inlet port which can be uncovered to the recess while the plunger is under the contact of the metering portion of the cam lobe. The sides of the recess are not parallel so that the amount of fuel which flows to the bore depends on the setting of the sleeve.

Abstract: A fuel injection pumping apparatus of the axially slidable rotary distributor type includes a cup shaped member mounted on a drive shaft and a distributor member which as a bore containing pumping plungers. The outward movement of the plungers is controlled by a tapered surface on the interior of the cup shaped member which co-acts with complementary surfaces on cam followers, disposed between the plungers and a surrounding cam ring. The slots in the cup shaped member which accommodate the followers are of helical or like form and the distributor member is driven angularly by tongues which are secured to the distributor member and which locate in the slots. As the distributor member moves axially it is also moved angularly by the action of the helical slots so that the timing of delivery of fuel remains constant.

Abstract: A brake circuit for a vehicle having selectively brakeable rear wheels comprises separate master cylinders each connected to one rear wheel brake and separately operable by means of foot pedals. The outputs of the master cylinders are connected to a control valve which in turn is connected to front wheel hydraulic brakes of the vehicle. When either of the pedals is depressed without depressing the other pedal the control valve is effective to isolate the front brakes from the pressurized rear brake circuit. However, when the brake pedals are linked together by a plate so that both rear brakes are operated together with control valve establishes a communication between the output of one master cylinder and the front brakes, thereby allowing four wheel braking.

Abstract: The pipe coupling has an annular flange member having a tapered inner surface portion and a plurality of holes therethrough. Bolts project through the holes. A pipe-engageable collet is mounted in the flange member and has a tapered outer surface portion engaged with the tapered inner surface portion. An annular, retainer element engages a surface of the flange member from which the bolts project and overlaps an outer peripheral portion of the seal back-up member and has a plurality of holes therethrough which are in substantial alignment with the holes through the flange member. The bolts project through the holes in the retainer element whereby the bolts and the retainer element are retained in position by virtue of their mutual interengagement and the seal back-up member and collet are retained in position by virtue of the engagement of the retainer element with the seal back-up member.

Abstract: An hydraulic brake actuator comprises opposed pistons which work in bore portions in a housing and fluid pressure in a pressure chamber urges the pistons in opposite directions to separate adjacent ends of a pair of brake shoes. A pressure proportioning valve controls communication between pressure spaces constituted by the pressure chamber. The valve is normally open to equalize the pressure in the pressure spaces but closes at a predetermined pressure so that any further increase in pressure is operative in only one pressure space, the pressure in which space acting to keep the valve closed. In use in a brake of the one-leading one-trailing shoe-drum type the increased pressure acts on the piston which applies the trailing shoe to the drum, in order to equalize the torque.

Abstract: A wheel slide protection system for a vehicle, such as a car or motor cycle, has a modulator valve (25) controlling the supply of pressure fluid to a wheel brake (22) sensing device (9) for sensing an incipient wheel slide condition of the braked wheel and providing a signal to cause the valve (25) to apply a slide-corrective modification to the braking force, and a pump (13) supplying the modulator valve and incorporated in an axle assembly (15) adapted to carry the wheel (16) to be braked. A fluid reservoir (12) and the modulator valve may additionally be incorporated in the axle assembly (15).

Abstract: In a master cylinder and servo booster assembly for a vehicle braking system a mounting plate is connected to the rear end of a vacuum operated servo booster. A tubular extension integral with the mounting plate extends sealably through the movable wall of the booster substantially to relieve the booster housing of braking reaction forces. Circumferentially spaced axially extending slots divide the extension into axially extending arms which are secured to the master cylinder housing at their free ends by the engagement of a radially extending projection on the end of each arm with an annular recess in the outer surface of the rear end of the master cylinder housing. A sleeve integral with the front shell of the booster housing encircles the ends of the arms and holds the arm ends in interlocking engagement with the master cylinder housing. Alternatively, projections on the master cylinder housing and recesses on the ends of the arms may be provided to secure the arms to the master cylinder housing.

Abstract: A liquid fuel pumping apparatus includes a centrifugal weight mechanism 14 which is coupled to a fuel control member through a lever. A spring is provided to oppose the action of the weight mechanism and this is coupled through a lever having an adjustable pivot point, to the lever through a closure member carried about an axially movable member coupled to the weight mechanism. A drilling in the member is supplied with liquid under pressure at a restricted rate. The pressure of liquid acts upon the closure member to urge the closure member relative to the member so as to uncover a groove communicating with the drilling. The pressure of liquid in the drilling is controlled so that it varies in accordance with the square of the speed and in the event that the pressure fails the closure member and the axially movable member will move relative to each other to cause a reduction in the fuel supplied by the apparatus.

Abstract: A heat spreader has a thin ceramic layer plasma sprayed onto its lower surface which may be chamfered. The upper surface of the spreader is then plated with a thin nickel or gold layer and a semi-conductor power device is soldered to the latter. The spreader is then secured via the ceramic layer to a base material serving as a heat sink by a layer of epoxy resin loaded with silver particles. The thin ceramic layer electrically insulates the spreader from the base material but enables heat conduction therebetween. The application of the plasma sprayed ceramic layer to the spreader is easy and economical to effect.

Abstract: The timing of delivery of fuel to a compression ignition engine is determined and adjusted by observing the peak pressure attained in a combustion chamber during a fueled working stroke of the engine. This is compared with a derived peak pressure and a timing adjustment made. The condition of the engine is taken into account by comparing an actual pressure ratio with a desired pressure ratio, the actual pressure ratio being determined by obtaining a peak pressure signal when fuel is supplied or a pressure signal at a fixed point in the working stroke before fuel is supplied. The desired pressure ratio is provided by a circuit to which signals representing engine speed and fuel quantity are supplied.

Abstract: An hydraulic actuator comprises a first piston and a second piston both working in a bore in a housing and the actuator incorporates a pressure proportioning valve. The valve comprises a valve head for engagement with a seating, first and second stems projecting from the head and through the first piston in each of two opposite directions, each stem being of an area smaller than that of the head, a seal between the first stem and the first piston, a first spring acting between an abutment adjacent to the seal and a shoulder on the first stem to urge the head in a first direction away from the seating and into engagement with a stop, and a second spring acting on an enlargement on the second stem also to urge the head in the first direction and to augment the force in the first spring. The second piston is provided with a longitudinally extending recess into which the second stem and the second spring both project.

Abstract: A drive circuit for an electromagnetic device includes an inductor which can be connected across a pair of supply lines by way of a first switch. Energy is stored in the core of the inductor which can be released into the device to cause rapid operation thereof by opening the first switch and closing a second switch. When the energy in the inductor has been dissipated a low level of current is allowed to flow into the device by way of the inductor from the supply lines and this flow of current can be maintained by means of a diode when the first switch is closed to re-energize the inductor.

Abstract: A fuel injection pumping apparatus for supplying fuel to an internal combustion engine comprises an injection pump to which fuel is supplied by a low pressure pump. A part of the injection pump defines a surface against which a control pressure can act to vary the amount of fuel supplied by the injection pump, the part being spring loaded by a spring in a direction to oppose the force exerted by the control pressure and to increase the amount of fuel supplied. The control pressure is derived from the low pressure pump by means of a control system and if the output pressure of the low pressure pump should fall due to for example fuel starvation, the part will move in the direction to increase the amount of fuel supplied by the apparatus, this being permitted even though the output pressure is reduced.

Abstract: A liquid fuel injection pumping apparatus of the rotary distributor type has stop means defined by complementary inclined surfaces on a rotary portion, coupled to a drive shaft and on the cam followers associated with the pumping plungers. The cam followers and the distributor member are axially movable to vary fuel quantity. In order to vary the initial rate of fuel delivery one or a reduced number of plungers only is arranged to deliver the initial flow of fuel. This is achieved by axial adjustment of one or more cam followers relative to the distributor member so that the associated plunger or plungers can move outwardly further during the filling stroke of the apparatus and will therefore be moved inwardly before the remaining plungers. Alternatively an axially movable part may be provided on said rotary portion.

Abstract: In an hydraulic system a solenoid-operated valve mechanism is used to control delivery of pressure fluid to a part of the system, the fluid being circulated by a pump from a reservoir through the valve mechanism and back. The valve mechanism has a solenoid-operated valve biassed open, and closed when the solenoid is energized to generate pressure fluid, the valve then being operated in response to the pressure and a pressure-responsive valve-opening mechanism, such that when the pressure rises above a first threshold level the pressure acts to keep the valve closed, until the pressure reaches a second threshold level at which the valve-opening mechanism is operative to cause the valve to open provided the solenoid is de-energized. The valve-opening mechanism comprises a valve which opens at the second threshold level to allow pressure fluid into a cavity defined by a piston to cause the pressure to fall and the valve to open.

Abstract: A friction pad assembly comprises a backing plate having friction material secured thereto, and an anti-rattle spring having a bent portion intermediate its ends, the bent portion seating in a recess in the backing plate. To avoid problems caused by heat when the spring is held in place in the recess by the friction material and located before heat bonding of the friction material, the recess is accessible to secure the spring to the backing plate after the friction material is secured to the backing plate. The bent portion is preferably retained in position in the recess by its own resilience.

Abstract: An electrical switch comprises a body, including a base, an operating member supported by the body for rotational and axial movement relative thereto, an aperture extending through the base and a light source support member received in said aperture. The support member and the wall of the aperture are so shaped that the support member can be located in the base in either of first and second different axial positions relative to the base. The support member includes a blocking element, which in the first axial location of the support member relative to the base extends into the path of either axial or rotational movement of the operating member relative to the body to prevent such movement of the operating member relative to the body. The second location of the support member relative to the base is such that said blocking element lies out of the path of either axial or rotational movement of the operating member so that both movements of the operating member relative to the body are permitted.