GB292955A - Device for the simultaneous tuning of circuits by the simultaneous variation of the coefficient of self-induction of the coils of the said circuits - Google Patents

Abstract

292,955. Bonnett, L. June 27, 1927, [Convention date]. Void [Published under Sect. 91 of the Acts]. Transformers.-Wireless receiving or transmitting and other circuits are simultaneously tuned by moving metallic screens relatively to inductance and transformer coils. Cylindrical coils 1, 2, 3, Fig. 1, may each be arranged between hollow copper cylinders 4, 4<a> connected together mechanically and optionally electrically at 8 and all carried by a bar 7 operated by a sliding control rod 9. The rod 9 may be directly operated or may comprise a rack driven by a control pinion. The cylinders 4, 4a may be relatively movable, the cylinder 4<a> being carried by a control rod screwing through a square extension of the cylinder 4 for adjustment of the cylinder 4<a> within the cylinder 4 and the extension sliding in a square bearing in a fixed guide for simultaneous movement of the cylinders 4, 4<a>. The inner cylinder 4a may be solid and the outer cylinder may be omitted. In a radioreceiver with intermediate-frequency transformers each with a sectional primary 57, Fig. 7, and a sectional secondary 58 a central rod 59 and a disc 62, with or without an outer cylinder 60, are moved near the sections 58 of each transformer. In a frequency-changing radio receiver, Fig. 6, with aerial and grid coils 26, 33 connected to a valve 28 as shown, a coil 44 in the anode circuit of this valve 28 is coupled to a coil 45 between the filament 48 and the outer grid 47 of a two-grid valve 43 connected as shown to coils 49, 51 for generating local oscillations and to a filter circuit 54, 55 receiving the resulting oscillations. Cylinders 26<a>, 33<a> with or without an outer cylinder 41 co-operate with each of the coil-pairs 26, 33, 44, 45, 49, 51, the cylinders being all mounted on a common control, those of the pair 26, 33 being earthed and those of the pair 49, 51 being insulated from the remainder. The coils may be moved, the screens being stationary.