Abstract: An electro-magnetic device comprises a first annular member and a second member having a cylindrical surface, the two members being interengaged. The presented surfaces of the two members are each provided with a two start or a multiple of a two start, thread formation thereby defining helical ribs on the two members. A winding is wound on the second member the winding arrangement being such that in the grooves or adjacent grooves the direction of current flow will be in the opposite direction when the winding is energized whereby the two members will move relative to each other to align the ribs on the members.

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 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 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.