| 摘要 |
PROBLEM TO BE SOLVED: To rotate an intermediate barrel to exceed rotational amount regulated by helicoidal coupling. SOLUTION: The helicoid device is provided with guide projections 41 and 53 separated by grooves 42, 57 and 58 at the terminals of respective helicoid lines 21 and 22, and is equipped with an inducing means to regulate the intermediate barrel 12 moved to a terminal position in an optical axis direction in terms of its position by making other guide projections 41 and 53 enter the grooves 42, 57 and 58 formed on the helicoid lines 21 and 22 when the intermediate barrel 12 is normally rotated after canceling the screwing of the helicoid lines 21 and 22, and also to return the intermediate barrel 12 from the terminal position to the optical axis direction so that the helicoid lines 21 and 22 may be screwed with each other when it is reversely rotated to a position where the screwing of the helicoid lines 21 and 22 is canceled by reversely rotating the intermediate barrel 12 after the normal rotation after it is moved to the terminal position. COPYRIGHT: (C)2006,JPO&NCIPI
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