Abstract: A vehicle speed control system comprises a memory which stores a signal Vr representing desired road speed which is compared in a comparator with a signal Vs representing actual speed. An actuator responds to any error by adjusting the engine to bring the vehicle to the correct speed. Units are provided to enable the driver to increment or decrement the stored desired speed by small amounts (e.g. 0.5 miles per hour). By means of switches, he can switch into the memory either one of two preset desired speed values. He can also modify these present values, by feeding in, instead, the actual road speed of the vehicle, such modified preset values remaining until the engine is next switched off. The system incorporates a "SOFT OFF" feature, by which, under certain switch off modes of the system, the engine power is not shut off abruptly but at a controlled rate. The system is advantageously implemented by means of a microprocessor.

Abstract: An override mechanism is disclosed for connection between the accelerator pedal of a vehicle and the fuel supply for normally enabling the driver to adjust the fuel supply but which can be overriden by speed limiting means. The throttle pedal is connected to move a lever to increase the fuel supply. This lever is pivoted to a clamp member via a shaft. The clamp member is clamped to a shaft whose angular movement adjusts the fuel supply. A spring resists pivoting movement of the lever with respect to the clamp member and therefore movement of the pedal is normally transmitted direct to the clamp and adjust the fuel supply. However, when the speed reaches an upper limit, an actuator pulls on a cable which is clamped to a part rigid with the clamp. Therefore the part moves relative to the cable carrier and the lever against the force of the spring. The clamp therefore closes the fuel supply.

Abstract: An electric motor driven actuator comprises an electric motor whose rotation causes rotation of a planet carrier carrying planet gears which engage an annulus gear on the inside of a stationary ring. A pinion transmits rotation of the planet carrier to further planet gears which are carried on another planet carrier and engage another annulus inside an axially movable ring. This ring can be moved axially by an armature in dependence on energization of an electro magnetic coil within a housing. When the ring moves towards the first-mentioned, stationary, ring, face teeth which it carries engage face teeth on the latter ring, and the axially movable ring is thus held stationary. Its planet carrier thus rotates and a coupling rotates a shaft which, via a tape, transmits drive to an output cable. When the coil is de-energized rings, separate again and the axially movable ring is no longer held stationary and its planet carrier no longer rotates.

Abstract: An indicator panel 20 has an array of LED's 25A to 25Q to provide an indication to the driver of a road vehicle, particularly a diesel-powered truck, when he should change to the next highest gear during acceleration from rest or low speed. The LED's are lit progressively as the engine speed increases in each gear and, when lit, emit green light if the engine speed is below the optimum change-up speed for that gear. When the engine speed begins to exceed the optimum change-up speed, the next LED illuminated produces red light to the driver. An audible warning may also be produced. If the driver does not change up in response to such warning, further red LED's will show and a more strident audible warning may be given. The change-up speeds to which the system responds are pre-set so as to be the optimum speeds for increased fuel efficiency. The change-up speed corresponding to the lowest gear is relatively low and increases successively for the successively high gears.