| 摘要 |
The contact wheel, driven by the hour wheel of the movement, carries an axisymmetric central contact spring with four arms (4,6,8,10) touching conductive tracks (T1-T5) on a printed circuit board. The geometry of the arms ensures a periodic variation of the interconnections between the tracks. Three tracks (T1-T3) subtending equal angles of about 50 degrees at the centre are distributed uniformly around one half of the ring. Three pairs of tracks (T4,T5) individually subtending about 20 degrees are arranged around the other half. An electronic control signal processor memorises the contact configuration in the initial position, and detects any one-hour movement of the wheel. |
