| 摘要 |
PURPOSE:To enable to realize the requirement for 12hr unlocking easily through a minimum exchange of parts by the use of a 24hr system unlocking mechanism by so arranging the coincidence detection of a detection pair constituted of a detecting wheel and a set wheel that it is made once in a 24hr system and twice in a 12hr system. CONSTITUTION:An additional hour wheel 2' is provided to an hour wheel 2, and a detecting wheel 4 is meshed therewith. Since the speed reduction in a ratio of 1:2 is accomplished by the wheel 2' and the wheel 4, the wheel 4 makes one revolution in 24hr and the coincidence detection of the detection pair is accomplished once in one revolution of the detecting wheel, whereby the alarm operation of the 24hr system is carried out. In this case, the wheel 4 has three projections 9 and a setting wheel 5 has three holes 10 corresponding to these projections 9. In order to make unlocking operation of the 12hr system, the 24hr system is converted to the 12hr system simply by exchanging the set wheel 5 with the one provided with holes 10' of twice the number of holes of said wheel. |
