GB1103298A - Calendar timepiece - Google Patents

Abstract

1,103,298. Calendar timepieces. EBAUCHES S.A. Jan. 24, 1967 [Feb. 22, 1966], No. 3598/67. Heading G3T. The control mechanism for the date indicator 1 of a calendar timepiece comprises two coaxial wheels 7, 11 rotatable at slightly different speeds and connected together by a spring 14 which becomes stressed as the angular displacement between the wheels increases, the wheel 7 being released once every twenty four hours whereupon its abrupt rotation indexes the date indicator one step forward. Pinions 8 and 13, fastened together on a hub 8a, drive the wheels 7 and 11 respectively, the wheel 7 having more teeth than the wheel 11. The spring 14 is located in a recess (15), Fig. 2 (not shown) in the lower surface of the wheel 11 and the ends 14a, 14b of the spring are bent at right angles to engage sector shaped openings 17 and 18 in the wheels 11 and 7 respectively. Initially the openings 17, 18 are aligned, but as the pinion 13 drives the wheel 11 at one revolution in twenty four hours, the wheel 7 is driven at a slightly slower speed by the pinion 8. The openings 17, 18 are relatively displaced and the spring stressed until a cut away segment 19 of the wheel 7 releases the wheel from its pinion 8. The sudden rotation of the wheel 7 then causes its pin 6 to engage teeth 5 of the date indicator which is advanced by one step. A detent 4 locates the indicator 1 in each position. To conserve power in an electric timepiece, the detent 4 may be raised at the moment of advancing the indicator, the pin 6 remaining in the path of the teeth 5 at the end of the operation to prevent the indicator advancing two teeth at a time.