GB452188A - Improvements in and relating to high frequency tuning coils - Google Patents

Abstract

452,188. Electric inductances. MICHAELIS, E., 14, Talbot Square, Hyde Park, London. Dec. 30, 1935, No. 36005. Convention date, Dec. 28, 1934. [Class 37] In a high-frequency tuning-coil, for use in coupled circuits and having an internal core of compressed iron powder and two annular cores or an annular and a disc-shaped core of the same material, and in which the inductance of the coil is adjusted by varying the gap between the inner core and one of the annular cores or the disc-shaped core, a separate support for the adjustment means and for the coupling coil is dispensed with by providing an extension on the tuning coil support or on the internal core which serves to carry the coupling coil, while the adjustment means is in screw-threaded engagement with a further extension on the coil support. In the form shown, the tuning coil support a is provided with an extended flange 1 which is used for attaching the device to a supporting plate and is provided with an internal core c and with annular masses b<1>, b<11> all of compressed iron, the latter being attached to the support a. The support is provided with an extension a<1> on which the coupling coil d is supported and with a further extension all, which is screw-threaded to co-operate with a screw of artificial resin or metal attached to the core c. In a modification, the adjustment means is in the form of an iron disc carried by a screw-threaded support of artificial resin which engages in a tubular extension on the end flange of the coil support a, while in a further construction, this form of adjustment device is employed, but the internal iron core itself extends beyond the flanged end of the support a and forms the extension on which the coil d is mounted.