GB1536982A - Electronic alarm timepieces - Google Patents

Abstract

1536982 Electronic alarm watches DAINI SEIKOSHA KK 17 March 1977 [19 March 1976] 11384/77 Heading G3T In an electronic alarm timepiece, an analogue time display is given by hands driven by a stepping motor, and pre-set alarm time is displayed in a window W Fig. la (not shown) in digital form by numbered discs. When a stem is pulled out the timepiece is stopped and rotation thereof in one or the other direction moves the hours or minutes hands respectively. To set the alarm time, the stem is pushed in. When rotated in one or the other direction it moves the hours disc or the minutes disc respectively. Each disc carries a ring of numbers and a corresponding ring of magnetic inserts 17a, 17b, Fig. 1c. A respective Hall element 16a, 16b is fixed adjacent each disc and the number of pulses produced thereby is a measure of the extent of movement of the respective disc. The Hall elements (16a, 16b) Fig. 1c are represented by switches Sa, Sb respectively, in Fig. 2 and the pulses therefrom are used to set an alarm time into the hours counter M24HC and minutes counter M60MC respectively. In Fig. 2, a crystal controlled oscillator 21 is followed by a frequency divider 22 having a 1Hz output to a motor drive circuit 23. The 1Hz signal is also fed to seconds, minutes and hours timekeeping counters 24, the contents of which are compared in a circuit 26 with a pre-set alarm time stored in counters 25. Coincidence results in an AND gate A2 passing a control signal to an A.F. oscillator to sound an alarm. The alarm oscillator may also be actuated for testing, by closing a switch Sd. A 12 hour or 24 hour clock system may be employed.