GB1394482A - Electronic switch for timepieces - Google Patents

Abstract

1394482 Electronic timepieces TIMEX CORP 8 Jan 1973 [10 Jan 1972] 1011/73 Heading G3T A battery-powered electronic timepiece, comprising an oscillator circuit followed by a frequency divider circuit and a driver stage operable to apply synchronizing and drive pulses to an electro-mechanical oscillator (e.g. a balance wheel), is provided with a delay circuit which opens a switch means to virtually disconnect the battery from the oscillator circuit when the electromechanical oscillator is stopped for a predetermined time interval, (e.g. 5 seconds). Thus, when it is desired to store the timepiece, the crown and stem may be pulled outwards causing the balance wheel to be held stopped and the delay circuit operates the switch means to substantially eliminate drain on the battery. In Fig. 1, a switch 16 in series with a drive transistor 11 and drive coil 17, is intermittently closed by the balance wheel. A delay circuit 18 is normally reset to zero each time a positive pulse appears at the drain 13 of the drive transistor 11, i.e. twice per balance wheel cycle. If no pulses appear, thereby signifying that the balance wheel has stopped, the delay circuit completes its timing cycle of say 5 seconds whereupon it turns off a switching transistor 19. Thereby the battery is disconnected from the oscillator circuit &c. When the balance wheel is later released it closes switch 16 resetting the delay circuit and turning on transistor 19 which starts the oscillator 10 (e.g. quartz crystal controlled). In an alternative embodiment Fig. 2 (not shown), transistor switches (39) (45) are cohtrolled by the output of the delay circuit (38). When the delay circuit completes a timing cycle the transistor (39) is turned ON thereby halting the oscillator circuit and the transistor (45) is turned ON thereby turning off the drive circuit transistor (31) and preventing its saturation during the storage period.