GB1392049A - Circuit for the drive of a clockwork mechanism regulator-oscillat or of a timepiece - Google Patents

Abstract

1392049 Electronic timepieces; automatic current regulation JUNGHANS GmbH Gebr 14 July 1972 [28 July 1971] 33203/72 Headings G3T and G3X A drive circuit, Fig. 1, for an electro-mechanical oscillatory member (balance wheel) in a timepiece is provided with a constant current circuit 12 preferably as detailed in Fig. 3, or alternatively as Fig. 2 (not shown) and connected between terminals 10, 11 in order that the charging current of a bias capacitor C may be maintained substantially constant independently of the voltage of a battery Uo. Thereby changes in bias voltage due to aging of the battery, are substantially eliminated. The drive circuit includes drive and control transistors T 1 , T2 respectively and drive and control coils L 2 , L 1 respectively, coaxially or concentrically wound and co-operative with a magnet system including magnets 23-26 on a balance wheel comprising a pair of magnetic discs 21, 22, Fig. 4, with counterweights 30. A capacitor CN is provided to suppress feedback oscillations due to close coupling of the coils. When capacitor C is sufficiently charged transistor T 1 is biased ON and a drive pulse is applied to coil L 1 , which moves the balance wheel. Alternate half cycles of A.C. voltage induced in coil L 2 by oscillatory movement of the magnet system relative thereto, control transistor T 2 and the remaining half cycles of, induced voltage control T 1 . Thus T 1 is blocked and C discharges through T 2 when T2 conducts and vice-versa.