| 摘要 |
PURPOSE:To surely detect the specific states of a first and second gears while the gears stand still by deviating the central point of the hole of the first gear from the central point of the reflecting plate on the second gear in the reversing direction of the first gear. CONSTITUTION:When a hole 2b formed through a gear (transmission gear) 2 and a reflecting plate 3a provided on a gear (minute-hand gear) 3 stand still in a crossing state, the central point P1 of the hole 2b is deviated from the central point P2 of the plate 3a in the reversing direction of the gear 2. In other words, the hole 2b is made larger by the deviated amount. While the hole 2b crosses the plate 3a when a right time has come, the gear 2 is affected by the swinging of a rotor gear and starts to swing. Due to such a constitution, however, the point P2 is not shielded even when the hole 2b reaches the maximum angle from the standing still position. Since the swinging amount of the gear 2 becomes smaller thereafter, the point P2 is never shielded. Therefore, a light receiving signal is stabilized at level '1' without swinging at the right time and a control circuit discriminates that the exact hour has come. |
