GB1205962A - Calendar timepiece setting mechanism - Google Patents

Abstract

1,205,962. Calendar timepieces. HAMILTON WATCH CO. Oct.2, 1967 [Nov. 10, 1966], No.44820/67. Heading G3T. A setting mechansim for a calendar timepiece comprises detent means for holding a setting stem 26 in three positions in which the stem 26 is coupled respectively to (a) a setting wheel 64 (b) a date including means, such as a date ring 30 for setting the latter, (c) a dial train, including a minute wheel 94, for setting the hands of the timepiece. The detent means comprises a lever 86 carrying a follower 90 engaging and movable with the stem 26 to rotate the lever 86 about a pivot 88 between three positions in which it is held by the engagement of the tip 80 of a spring arm 78 with either or both of two pins 82, 84. A toothed clutch 60, slidable on and, rotatable with the stem 26, is engaged by a projection 72 on a lever 66 carrying the setting wheel 64 and biased by a spring 70 in a counter clockwise direction in Fig.3. The stem 26 is shown in Fig. 3 in its innermost position in which the toothed clutch 60 engages the setting wheel 64, and in which rotation of the stem 64 performs no other function in an electrically driven watch than rotate the members 26, 64, but the clutch 60 meshes with a ratchet wheel to drive the winding train in a spring driven watch. In the intermediate position of the stem 26 the setting wheel 64 engages both the toothed clutch 60 and the teeth 50 of the date ring 30 so that the latter may be adjusted by rotation of the stem 26; whilst in the outermost poisition of the stem 26 the setting wheel 64 engages both the toothed clutch 60 and the minute wheel 94 to enable the latter to be rotated to see the hands of the timepiece. As described in Specification 1,205,963 the date ring 30 is driven continuously by a pinion 112 integral with a triangular cam 114 and a staff 110, the cam 114 being engaged by a spring 118 secured to a toothed wheel 116 rotatable on the staff 110 and driven by the dial train. During setting of the date ring 30 by the stem 26 the pinion 112 and the cam 114 rotate relatively to the spring 118 and the wheel 116 so that the dial train is not affected. Alternatively the pinion 112 and the wheel 116 may be coupled by a slipping friction clutch. An apertured shutter 34 Fig.2 (not shown) rotates with the date ring and is advanced daily by cam mechanism to expose the appropirate date numeral.