GB258381A - Improvements in or relating to inductance coils - Google Patents

Abstract

258,381. Igranic Electric Co., Ltd., Alford, W. K., and Holdway, G. July 9,1925. Inductance coils for use in wireless apparatus are wound in slots 2, Fig. 2, formed in the outer edges of plates 1 arranged like paddle-blades inclined to the radial direction as in Fig. 1, each plate having side-edge slots 7, 8 engaging sideedge slots in both of its neighbouring plates to form a self-supporting structure without a hub. The slots 2 register axially in all plates 1 and the conductor is wound first in one set of registering slots until these are sufficiently filled, then in another set and so on to form axially spaced, spirally wound sections, these sections each having the form of a conical frustum when the slots 2 are inclined as in Fig. 2. An insulated conductor of diameter just fitting the slots 2 may be used and adjacent turns may be spaced by short lengths 9 of insulation within the slots 2. The dimensions may be such that the radial projection of any point of the outer turn of one section does not intersect the inner turn of the next section whilst that of any point of a turn of a section does not intersect either of the adjacent turns. A strip 11 holds the coil on a plug 10 with the outer edges of two plates 1 pressing against the usual metallic attachments 12. The Provisional Specification describes modifications in which the winding slots are radial or curved or of increasing dimensions and are in rectangular radial plates supported on a central former.