GB1465349A - Counter drive mechanism for use in a digital clock - Google Patents

Abstract

1465349 Digital clocks JECO KK 26 June 1974 [26 June 1973(3) 30 March 1974] 28352/74 Heading G3T [Also in Division G4] The specification describes several mechanisms for driving the counter of a digital clock each comprising a pair of rotary members on a common shaft with a torsion spring fixed between them one of the members being held against rotation until the other is turned by the input through a particular angle when the first is released for rapid movement under the action of the spring to bring stops 79, 80 on the two members into engagement. In Figs. 5, 7, shaft 20 with an attached cam member 18 is continuously rotated by a clock motor 44. Member 18 has four cam surfaces 35 which displace a two armed lever 19 which latches a four armed detent member 16 loose on the shaft 20 until lever 19 is displaced by the cam. A spring 24 between an anchor 22 on the shaft and the detent member 16 then drives the latter to step the lowest order number wheel 11 through a Geneva mechanism Fig. 6 (not shown). The cam member 18 carries a gear 61 which drives an indicator wheel 51 when the clock is operating. A knob 56 provides for pre-setting by rotating the wheel 11 on for starting the clock mechanism by a cam 58. In another embodiment Figs. 1-4 (not shown) the detent member 16 simply has gear teeth which directly drive the number wheel 11. In Fig. 12 a three lobed cam member 18 releases the latching lever 19 which acts on the teeth of the Geneva pinion 85.