GB1481530A - Electronic timepiece - Google Patents

Abstract

1481530 Electronic timepieces CITIZEN WATCH CO Ltd 28 Nov 1974 [26 Feb 1974] 51649/74 Heading G3T An electronic timepiece has arrangements for indicating the pending termination of battery life, although it is stated that alternatively the arrangements may indicate abnormal temperature or humidity within the timepiece or leakage of battery electrolyte. The indication may be the flashing of one of the time display digits in an electro-optical display, or the repeated alternate rapid movement and arrest of the display seconds hand driven by a stepping motor. In Fig. 2, from signals P 1 supplied by a crystal or tuning fork controlled oscillator a frequency divider 2 produces signal P 2 (Fig. 3) at 1Hz. Under normal operating conditions with the battery voltage above a predetermined value this signal is passed by a logic switching arrangement 5 to a display actuator 3, e.g. a step motor. A modulator 7 also receives P 2 and by means of a frequency divider 7f 1 produces a signal A at ¢ Hz. The signals A and P 2 are added in an AND. gate 7a to form a signal B at ¢ Hz. A signal Pc at 4 Hz is derived from a stage in divider counter 2 and is applied to an auxiliary signal generator 8 to produce signal P 8 at 4 Hz which is added to B in an AND gate 7b to produce a twin pulse 4 Hz signal P 7 at intervals of 2 seconds as shown Fig. 3. P 7 is applied to an AND gate 5b. A battery voltage detector 6 produces a low level and a high level signal P 6 when the battery voltage is above and below 1.3V respectively. Thus, normally, with P 6 at low level a gate 5b is blocked and an inverter converts P 6 to a high level before application to the AND gate 5a. Thereby gate 5a is opened to pass the 1Hz signal P 2 to an OR gate 5S and thence to drive the display second hand in 1 second steps. When P 6 is high, battery voltage low, the gate 5a is blocked and gate 5b is open to pass the twin pulse signal P 7 to OR gate 5S and thence to the display actuator 3. This causes the seconds hand to be repeatedly advanced quickly over a display portion corresponding to 2 seconds and then held stationary for 2 seconds, so giving a visual warning of a dud battery. In a modification Fig. 4 (not shown), if no action is taken within twelve days, trains of four pulses occurring at 4 second intervals are produced to drive the second hand, indicating that the voltage is so low the timepiece will soon stop. In the case of an electro-optical display the minutes may be caused to flash intermittently, controlled by signal P 7 , P 5 , and both the hours and minutes caused to flash when the remaining battery life is about twelve days. A.M., P.M. may be displayed.