GB252236A - Improvements in or relating to variable inductance devices - Google Patents

Abstract

252,236. Igranic Electric Co., Ltd., and Wright, S. R. Feb. 17, 1925. Wireless tuning-apparatus, adjustment devices for; inductances.-In variable inductance devices of the kind comprising main coil units relatively movable for coarse adjustments and a vernier coil unit movable for subsequent fine adjustments, the main coil units are arranged one within another and the vernier coil unit is located within the inner of the main coil units. In a variometer constructed as described in Specification 235,654 and comprising a coil 1 in the form of a hollow spherical zone rotatable about a diametral axis within a similar coil 2 within a protective tube 5, a vernier coil 19 consisting of three turns of stiff wire is mounted within the coil 1 and is rotatable about an axis at right angle to, and intersecting, the axis of rotation of the coil 1 bv disc-and-wheel friction gearing 22, 23 and a central shaft 24 passing through the hollow shaft 13 controlling the coil 1. All three coils 1, 2, 19 are in series between two terminals 29, 42, the coils 1, 2 being each in halves above and below the axis of rotation and the circuit passing through the upper half of the coil 2, the lower half of the coil 1, the soil 19, the upper half of the coil 1 and the lower half of the coil 2 successively. The coil 19 is carried on an insulating shaft with stub axles 18 serving as electric connections and engaging brackets on the insulating ring 3 supporting and connecting the two halves of the coil 1, a similar ring 4 supporting the coil 2. The shaft 13 may carry a peep-hole indicator X as described in Specification 240,983. The terminals 29, 42 serve as bolts for strips joining the ends of a flat sheet bent to form the tube 5. Instead of one or more turns of wire, the vernier-coil unit may comprise a copper disc rotatable about a diameter and connecting the two halves of the coil 1 or disconnected from the circuit. The variometers may be used in the anode circuit of regenerative valve receivers. The Provisional Specification describes a vernier-coil wound circumferentially on an insulating ring. Reference has been directed by the Comptroller to Specification 223,859 (as open to inspection under Sect. 91 of the Acts).