A displacement - electricity transducer contains a movable magnetic core and a fixed magnetic core oppositely arranged so as to have predetermined gaps or clearances in at least two places. Two substantially closed magnetic circuits, each including one of the gaps, are formed by both magnetic cores, so that when the movable magnetic core is displaced relative to the fixed magnetic core while maintaining a predetermined spacing therefrom, the substantially opposite area of the gap portion in one of the magnetic circuits increases, while the substantially opposite area of the gap portion in the other magnetic circuit decreases. A first coil is wound around a part common to the two magnetic circuits, while a second coil is wound around a part not common thereto. By applying an alternating current to the first coil, an output responsive to the displacement of the movable magnetic core is derived from the second coil.

A core with at least three elongated legs, at least one leg being centrally located among all the elongated legs, is joined at at least one end by a yoke portion connecting all the legs. The central leg or legs is wound with a magnet winding close to the yoke portion of the core, with which the core is excited with an alternating field. A short-circuiting ring structure, which may be in the form of an apertured plate, encircles at least the central leg or legs of the core and is movable in the direction of elongation of the core in accordance with the movement of a body the displacement of which is to be measured. The legs of the core may be bent in order to measure rotational or angular displacement. Movement of the short-circuiting ring along the length of the core varies the inductance of the coil in a predetermined manner, which may be a linear relation to displacement. A yoke and a winding may be provided at the other end in order to increase the sensitivity by a differential method of measurement.

A wheel is mounted on a rotating shaft and cooperates with at least one pair of inductors fixedly mounted in juxtaposition to the wheel. The wheel has at least one opening formed therein for generating a signal whenever the opening in the wheel is substantially aligned circumferentially with the pair of inductors. An electronic control circuit, responsive to the signal, actuates a remote meter for providing a remote indication of the shaft position. In a preferred embodiment, this improved sensing means is applied to the remote reading of a conventional household electric meter. Two pair of inductors are provided for cooperation with five equiangularly-spaced closed slots formed in the wheel, thereby providing ten signals (or counts) for each complete revolution of the wheel. The wheel is mounted on the shaft of the unit decade dial in the meter. The remote meter comprises a digital counter, responsive to the pulse generated by the electronic control circuit, for providing a remote digital read-out of the accumulated kilowatt hours on the meter.

An inductive transducer is provided with a core with legs extending in opposite directions from a yoke on which a coil is wound. On the leg portions extending on one side of the coil a short-circuiting ring displaceable in accordance with the displacement of a body the movement of which is to be measured is provided and on the leg portions extending on the other side of the coil a compensating short-circuiting ring is provided having a mass corresponding to the total mass of the first short-circuiting ring and the movable portion of the body to which it is connected and the connection therebetween. The effect of acceleration forces produces an equal shift of both short-circuiting rings in the same direction, leaving the total flux linking the coil substantially unchanged. The device can be adapted to measure either linear or angular movement.

An improved patient support structure comprises an articulatable frame, a plurality of elongated inflatable sacks, a low pressure compressed air blower and a plurality of pipes for carrying gas from the blower to the sacks. A multi-outlet, variable flow, gas valve comprises a housing defining an inlet and a passageway. The valve housing further defines at least two cylinder chamber communicating with the passageway and a discrete outlet for each cylinder chamber communicating therewith. A piston is substantially non-rotatably disposed inside each cylinder chamber and has a threaded opening through the center thereof with receives a threaded portion of a rotatable shaft therethrough. One end of the shaft is rotated by a motor, and the other end of the shaft is connected to an axle of a potentiometer.