GB1250066A - - Google Patents

Abstract

1,250,066. Electric timepieces. VOUMARD MACHINES CO. S.A. Aug.7, 1969 [Aug.8, 1968], No.39488/69. Heading G3T. The oscillations of a mechanical oscillator, e.g. a timepiece balance, are electromagnetically sustained by a system comprising two complementory transistors 6, 7 connected at the emitters to electrical, supply lines 11, at the collectors via a capacitor to a drive coil 2, and at the bases via capacitors 14, 15 to a control coil 1 which co-operates with magnets to provide an operative control pulse at each half oscillation of the mechanical oscillator, the pulses being alternately of positive and negative sign. The coils 1, 2, Fig.2, co-operate with two pairs of magnets 3-3, 4-4 on a balance 5 in such manner that during each half oscillation of the balance 5 three pulses are generated in the control coil 1, the second only being of sufficient amplitude to render conducting one of the transistors 6, 7 which are biased by resistors in leads 14, 15. Thus in two successive half oscillations of the balance 5 two drive pulses are provided in the drive coil 2 by the transistors 6 and 7 respectively.