Abstract: A gas turbine engine is supplied with fuel by way of a metering unit which includes a metering valve responsive to a servo pressure which is regulated by electrical signals from a control circuit. Failure of electrical signals to the metering unit results in the metering valve being arrested in its position at failure. A combined manually operable and shut-off valve arrangement is in series with the metering unit includes a valve which is normally biassed fully open and is operable by a manually regulated servo pressure. The manually operable arrangement also includes a device for setting the servo pressure of the valve in the metering unit to a value which maintains that metering valve fully open.

Abstract: An electrically controlled braking system, in which the operation of the brake actuation is split into three bands depending upon the brake demand level, such that at low demand in a first band the braking pressures are set to generate equal wear at the vehicle axles, and at higher demands in a third band braking pressures are set to apportion braking between axles dependent upon the axle loads being carried, while in a second band, located intermediate the first and second bands, the braking is gradually changed from being equal to being fully apportioned, the extent of this change-over depending upon the actual level of demand within this second band.

Abstract: A fuel control system for a gas turbine engine has a metering valve and a shut-off valve in series, and a spill valve for spilling fuel from upstream of the metering valve in response to an overspeed condition of the engine. The spill valve and shut-off valve are responsive to respective servo pressures, and an electrically operated valve can control both servo pressures in response to a demand to shut down the engine. The electrically operated valve can also control a third servo pressure for setting a minimum flow limiting stop in the metering valve to a lower limiting level during engine starting.

Abstract: A linear variable displacement transducer (LVDT) has a core connected to an actuator such as a torque motor. The outputs of the LVDT are demodulated and subtracted to provide a displacement signal which is compared with a desired displacement to provide closed loop control of the torque motor. The desired displacement is formed by multiplying a demand signal by the sum of the demodulated LVDT outputs so as to provide temperature compensation.

Abstract: A low pressure fuel supply system supplies fuel which tends partially to solidify at low temperatures and whose viscosity increases with decreasing temperature, from a fuel tank along a supply line, through a filter, to a fuel injection pump. A fuel recirculating circuit for recirculating fuel warmed by the injection pump extends from a return outlet of the injection pump, along a path extending through the filter to the injection pump inlet. A permanent bleed pipe extends to the fuel tank from the portion of the recirculating circuit between the injection pump return outlet and the filter. The flow-resistance-determining dimensions of the permanent bleed pipe are such that the pipe presents increasing resistance to the flow of fuel therein with decreasing fuel temperature. It therefore carries little flow at low temperatures of the fuel therein, most of the warmed fuel from the injection pump return outlet being directed into the filter.

Abstract: An electronic braking system in a motor vehicle capable of towing a standard trailer not having its own EBS system has a separate pressure control channel for the generation of a trailer service brake pressure signal in the event that a driver's braking demand is sensed at any axle of the towing vehicle. The pressure signal level is set in the towing vehicle so as to be a function of the driver's electrical demand signal modified in dependence upon the load exerted by the trailer on the towing vehicle as measured at a towing link therebetween.

Abstract: A fuel injection nozzle for supplying fuel to the air inlet duct of a spark ignition engine has a valve member movable to an open position when a solenoid comprising a plurality of layers of wire is energised. A negative temperature coefficient thermistor is connected in shunt with a number of the layers of the wire forming the solenoid.

Abstract: A fuel pumping apparatus of the rotary distributor type includes a main pumping plunger and an auxiliary plunger operable at the same time by a cam. During inward movement fuel is displaced by the pumping plunger to an outlet. The auxiliary plunger displaces fuel to a shuttle bore containing a shuttle and during the initial inward movement a first flow path to drain from the bore containing the pumping plunger is open but this is closed upon further movement of the shuttle until a second flow path is opened. The second flow path includes a groove having an inclined edge so that the angular setting of the shuttle determines the amount of fuel supplied through the outlet. A valve is also provided to allow fuel displaced by the auxiliary plunger to flow to a drain.

Abstract: In a spot-type disc brake guides are arranged between each of the arms of a brake support and the sliding caliper to permit displacement of the sliding caliper and the transmission of braking forces to the brake support. The guides each have a guide body comprising a groove extending in the direction of the axis of rotation of the brake disc as well as a projection engaging into said groove. To enable exceptionally high braking forces also to be transmitted by the caliper via the guides to the brake support, the groove and the projection of each guide, which upon braking in the operational direction of rotation of the brake disc is loaded with braking forces, have complementary circularly arcuate profiles in cross-section parallel to the brake disc.

Abstract: A hydraulic brake system comprising a master brake cylinder (10), a brake force booster (12) and a filling chamber (38) by means of which in the initial phase of a brake actuation the brake system on relatively short pedal travel is rapidly filled with hydraulic brake fluid up to a predetermined switch-off pressure, the filling chamber (38) being in conductive communication with a primary chamber (22) of the master brake cylinder (10) and connectable to a hydraulic fluid reservoir (62) via a first valve (82) which closes when the brake force booster (12) is functioning and a pressure obtains in the hydraulic fluid below the switch-off pressure and opens when the brake force booster is not functioning, is characterized in that in the connecting conduit (60, 72, 74, 78) between the filling chamber (38) and the primary chamber (22) a second valve (76) is arranged which closes at a pressure in the hydraulic fluid above the switch-off pressure.

Abstract: The valve casing (12) houses an adjustment member (50) which is movable, in response to a pressure difference between the inlet (14) and the outlet (16) of the valve (10), from an inoperative position into a stop position in which the adjustment member (50) prevents the full opening of the valve. In this manner, when opening the valve (10), throttling which can be predetermined at random as compared to the fully open state takes place during a period of time while there still is a pressure difference between the inlet (14) and the outlet (16).

Abstract: An apparatus is provided for determining the velocity and orientation of a vehicle, for instance to permit route guidance by dead reckoning. Two optical speed over ground sensors on the vehicle are arranged at acute angles to the longitudinal axis of the vehicle. One or more further sensors, such as a fibre optic gyroscope or one or two optical speed over ground sensors, are provided on the vehicle. The speed and direction from these sensors can be used by a data processor to perform dead reckoning navigation and the vehicle position can thus be determined.

Abstract: A brake actuator has a housing (4) containing a pair of brake-applying members (9, 10) interengaged by way of a threaded connection (11) to form a strut of which the length is variable by rotation of one of the members. One (9) of the members has a gear formation (16) thereon meshing with a corresponding formation (22) on a drive gear (21). The formation (22) has an extended profile permitting simultaneous rotational and translational movements of the member (9) relative to the drive gear (21) so that rotation of the drive gear causes expansion and contraction of the strut for brake actuation. The brake actuator housing (4) is mounted at a location adjacent the wheel while a power unit (10) is carried by a suspension member (1) in order to decrease noise and vibration transmition.

Abstract: An engine throttle control system comprises a control unit for controlling the position of a throttle by means of a motor in response to a position transducer actuated by an accelerator pedal. A detector detects when a signal produced by the control system is outside a range of acceptable values and, for instance, shuts down the engine. In one embodiment, the detector detects whether power supplied to the motor is less then a value expected on the basis of the position and speed of movement derived from the output of a throttle position sensor.

Abstract: The assembly includes a master brake cylinder (10) to which at least one brake circuit can be connected, a modulator (12) and a pneumatic braking force booster (14). For modulating the pressure in the brake circuit the modulator (12) is connected to the master brake cylinder (10). The braking force booster (14) comprises a housing (34, 36) having at least one partition (38) movable in piston-like manner. For transmitting reaction forces of the master brake cylinder (10) to a vehicle wall (20) at least one connecting pin (16, 18) extends through the housing (34, 36) of the braking force booster (14). The modulator (12) is likewise mounted with bypassing of the master brake cylinder (10) on at least one connecting pin (16, 18) which extends through the housing (34, 36) of the braking force booster (14). This avoids vibrations generated by the modulator (12) being transmitted directly to the master brake cylinder (10) and possibly damaging the latter in the course of time.

Abstract: A device for coupling a rotary member to an axially movable input stem of a linear displacement transducer comprises an axially movable element which is coupled to the stem and threadedly engages the rotary member. The axially movable element is restrained against rotation by spring loaded detents and has abutments which can engage a lug on the member when the element reaches its limiting axial positions. This engagement causes the element to be rotated with the member and input to the transducer is arrested.

Abstract: A brake actuator has a force applying device actuated by a rotary actuator shaft and arranged to separate opposed tappets to actuate braking elements. Each tappet includes a pair of threadedly engaged members which are relatively rotatable to enable the length of each tappet to be adjusted. An adjuster control device is operable to vary the length of one of the tappets and a transmission device interconnects the tappets to effect a corresponding variation in length of the other tappet. The transmission device, a ring gear, lies within the actuator housing at a location adjacent the axially inner end of the force applying device and cooperates with both tappets to transmit adjusting movement of one tappet to the other.

Abstract: On the caliper (10) of a spot-type disc brake a hold-down spring (40) of sheet metal is supported with a supporting region (42) formed thereon near a brake pad (28); from there it extends in cantilever manner beyond the brake disc (18). The hold-down spring (40) comprises two pairs of spring legs (50, 52) which are separated from each other by a first pair of axial slots (60) and in the relaxed state lie at least approximately in a common plane and extend beyond the brake disc (18). A first pair of the spring legs (50) presses against the brake pad (34) remote from the support region (42). A second pair of the spring legs (52) is separated by a second pair of axial slots (64) from a third spring leg (54) in such a manner that the second pair (52) and the third spring leg (54) are joined only at their ends remote from the support region (42) without being bent over. The third spring leg (54) presses with its other end onto the brake pad (28) adjacent the support region (42).

Abstract: A differential pressure control valve comprises a plunger (36) which is displaceable in a housing (30) by an electromagnet (32). By way of a stop (52) a first spring (44) presses the valve seat (V.sub.S) into its inoperative position against a first seat ring (60). In moving toward the valve seat (V.sub.S) the plunger (36) is cushioned by a second spring (42) before or as it touches the valve seat. Very sensitive actuation of the valve is obtained by the fact that the first spring exerts somewhat greater pressure than the second one.

Abstract: A digital control system for a gas turbine engine comprises two identical control lanes each of which includes a digital computer, two data buses, input circuits, output circuits and an interface unit. Each interface unit is arranged to multiplex data on the buses and transmit this data serially through a connection. Each interface unit is responsive to receipt of data from the other unit to generate control signals (read, write and valid address) for the received data, so that, in addition to timing signals on a further connection data only is transferred between the lanes.