| 摘要 |
PROBLEM TO BE SOLVED: To provide a collet which keeps a mounting radius of a balance spring unchanged. SOLUTION: The collet is formed of a band 10 wherein its inner contour 11 demarcates recesses 11a, 11b, 11c for incorporating the collet into a balance staff 2, while its outer contour 12 includes a working point 4 between the collet and a balance/spring 9. In this working point 4, range R from the center 0 of the balance staff 2 is longer than that of any other point 6, 8, 13, or 15 on the outer contour 12. The inner contour 11 has plural points 1, 3, 5 in contact with the balance staff 2, at least one contact point 1 matches with both the balance staff 2 and the working point 4. The opening angleαbetween the above contact points is the same or different, which changes width "I" of the band 10, while the contact points 1, 3, 5, 7 with the balance staff 2 unchange the post-incorporated range R. Thus such a friction torque that may change angle direction of the collet is not generated, nor imbalance produced. COPYRIGHT: (C)2006,JPO&NCIPI
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