GB1087970A - Improvements in calendar timepieces - Google Patents

Abstract

1,087,970. Date indicators. HAMILTON WATCH CO. Sept.30, 1966 [Oct.29, 1965], No.43901/66. Heading G3T. A calendar timepiece comprises a continuously rotated calendar ring 12 having date indicia 20 thereon, a shutter 43 having a window 56 overlying a portion of the calendar ring and a cam 84 which moves the shutter in synchronism with the calendar ring during each-24 hour period. An hour wheel 14 is coupled to an intermediate gear 28 by a calendar drive pinion 26 and an intermediate pinion 36 meshes with a calendar gear 38. A calendar pinion 42 is attached to the gear 38 and meshes with teeth 16 to drive the calendar ring 12. The cam 84 is attached to the staff 30 of the pinion 36 and the gear 28 and the outer surface 82 of the cam rotates the shutter 43 about a pivot 44 so that the window 56 follows the movement of the visible date indicium. Just before midnight, however, the stop portion 78 of the shutter cam surface 80 slips over the sharp edge of the cam surface 82 and a spring 70 engaging a pin 76 urges the shutter upwards so that the window coincides with the next date indicium. In order to set the hands and rotate the dial ring in either direction, a setting stem 68 is pulled outwards so that a pin 90 engaging a groove 88 in the inner portion of the stem rotates a lever 94 about a pivot 96. A pin 100, attached to the lever, presses against the shutter to move the cam surface 80 out of engagement with the cam 84 thereby freeing the shutter mechanism from the watch drive and allowing the calendar ring to be rotated in either direction.