Abstract
Various watches, each having a calendar mechanism, have been developed and produced on commercial basis, following the technique which has been cultivated through the age of the mechanical watch. In the conventional calendar mechanism, such a mechanism in which the date dial driven by a date dial driving wheel is general. However, in the calendar watch, it is necessary to correct the date at the end of the even month. On the other hand, a month-end no-correction watch is produced, in which the correction is realized by controlling a microcomputer IC and a calendar-exclusive gear train having a Geneva stop, using a logic circuit. However, in the mechanism, there are a backlash between the toothed portion of the date dial and the date dial driving portion, and a clearance in the Geneva stop, which may cause the chattering of the date dial and the deviation of the date indication from the date window. Therefore, aiming to mount on the 98-model of "The Citizen" pursuing a watch function based on the user principle, a calendar mechanism is developed, whereby the user is released from the trouble to correct the date at the even month and the leap year, maintaining the ease of use of the conventional analogue watch, and the chattering of the date dial, caused by the backlash and the clearance at the date dial driving portion which occurs when the date dial is driven by the calendar-exclusive gear train, does not generate, and the deviation of the date indication is obviated.
