Abstract: A fuel injection system for supplying fuel to a combustion space of an internal combustion engine includes a nozzle having a valve member urged to the closed position by fluid under pressure derived from an accumulator. A displacement piston is movable to supply fuel under pressure to the nozzle upon opening of a solenoid operable valve and return motion of the piston is effected by closing the valve and opening a further solenoid operated valve. The return motion of the piston is achieved by fuel under pressure supplied to one end of the cylinder containing the piston.

Abstract: An electromagnetic device comprises an annular member and a core member the latter having formed in its slots and the annular member having projections located in said slots. The projections and the adjacent wall of the slot define attraction faces which when a winding located in the slot is energized, are attracted towards each other thereby to produce relative movement between the members. The other faces of the projection are provided in accordance with the invention, with a coating of an electrically conductive material so that when the windings are energized eddy currents flow in the conductive material which act to assist the relative movement of the members.

Abstract: An electrical transformer comprises a core structure formed from magnetizable material and comprising a first annular element in the peripheral surface of which is formed at least a pair of helical slots. The core structure includes a second element which closes the open ends of the slots and located in each slot is at least two windings forming the primary and secondary windings of the transformer. Each winding extends along one slot and returns along the adjacent slot.

Abstract: An electromagnetic device comprises a pair of a plurality of pairs of helical coils the turns of the coils being alternatively arranged. Each of the coils is formed from a length of tubular magnetizable material and within each coil is an electrical conductor. The conductors in the turns of adjacent coils carry electrical current in opposite directions and the walls of the coils which are adjacent each other are of reduced section so that when the conductors carry electrical current, magnetic flux leakage occurs and the turns of the coils separate thereby producing an extension of the coils which is transmitted to a pair of members.

Abstract: An actuating device comprises an elongated member formed from a material having the property of magnetostriction and a winding which can be energized to cause flow of magnetic flux in the member so as to cause a physical change in the dimension. The elongated member is divided into a plurality of magnetic circuits disposed along the length of the member and portions of adjacent magnetic circuits are adjacent each other. The directions of flux flow in adjacent magnetic circuits is such that in said portions of two adjacent circuits, the flux flows are in the same direction.

Abstract: An electro magnetic device comprises a pair of relatively movable magnetizable members which have surfaces disposed in face to face relationship. One of the members is provided with spaced projections which locate in spaced slots formed in the other member, the projections having a smaller width than the slots so as to permit limited relative movement between the members. Some or all of the slots accommodate an electrical winding, the connection of the winding or windings being such that any two slots in which the flow of current in the windings therein is in the same direction are separated by a slot with either no winding or with a winding in which the flow of current is in the opposite direction. When the winding or windings are energized and when the projections are not centrally disposed in the slots, the members will be urged relative to each other to reduce the size of the smaller gap between each projection and the side face of the associated slot.

Abstract: A d.c. motor control system includes a pair of armature windings mounted on a single rotor or on a pair of mechanically coupled rotors, and a field winding or windings. The system includes switch means operable to effect a change in the electrical connections of the armature windings to a pair of electrical supply terminals and means for effecting variations of the current flowing in the field winding or windings.

Abstract: A wheeled vehicle includes a wheel carrying axle upon which the weight of the vehicle and its load is carried through the intermediary of a spring. The spring is coupled to the axle by means of a mounting unit which includes a pair of spaced mounting plates and also a pair of spaced supporting plates which are disposed in spaced relationship relative to the mounting plates. Interposed between the support plates and mounting plates are sensing elements and the support plates and mounting plates are clamped together by means of bolts. The upper sensing elements are subjected to the clamping force together with the weight of the vehicle and its load, whilst the lower sensing elements are only subjected to the clamping force. The sensing elements are connected into a bridge circuit.