GB1486135A - Electric timepiece - Google Patents

Abstract

1486135 Electronic timepieces FUNAI ELECTRIC CO Ltd 30 Jan 1975 [18 July 1974 22 July 1974 (3) 26 July 1974] 4124/75 Heading G3T [Also in Division H3] An electronic timepiece energized by A.C. mains, uses the mains frequency as a timing reference and has means which, following a power supply interruption, warn that the time displayed is incorrect. The timepiece may be combined with a radio receiver and switches the receiver ON or OFF automatically at predetermined times to function for example as a waking alarm. The timepiece comprises a gas discharge time display tube 2, Figs. 2, 4, driven by an LSIC timing circuit 28 which receives timing reference pulses from power supply circuit 27. Following a power interruption colon dots remain unenergized until the time display is advanced to the correct time by manual operation of a switch 55. Alternatively the colon dots may be maintained continuously ON as in Fig. 5 arrangement (not shown), the colon dots being repeatedly switched ON/OFF when the correct time is being displayed. In another alternative Figs. 6 and 7 (not shown), illumination of the gas discharge tube 2 is prevented until the time advancing switch 55 is operated; in Figs. 8, 9 (not shown), a warning lamp or buzzer is opereated and in Figs. 10, 11 (not shown), an outage detection circuit resets the time display to 00:00 the reset being maintained by a charge on a capacitor until the time advancing switch is operated. In a further alternative, Fig. 19 (not shown), a shutter is moved across the display in the event of mains failure. Interference with the radio by the clock is reduced by enclosing the clock unit in a metal box as in Figs. 12, 14 (not shown), the display tube being viewed through a metallic mesh, or a light penetratable shield in the form of a coating or film.