| 摘要 |
PROBLEM TO BE SOLVED: To obtain an advance/retreat cam mechanism for a lens barrel where the miniaturization of a cam ring is made compatible with the securing of the moving amount of a movable member. SOLUTION: In the advance/retreat cam mechanism for the lens barrel equipped with a movable member supporting an optical element and guided to advance straight in the optical axis direction, and a cam ring having a cam groove which a cam follower arranged on the movable member is engaged with on its peripheral surface, either front or rear end of the cam groove is opened to the end face of the cam ring, and the cam follower is made to retreat/advance in the open end of the cam groove in accordance with the normal and reverse rotation of the cam ring. The cam mechanism is provided with a movement regulation part restricting the leaving or the leaving amount of the cam follower to the outside of the cam groove from the open end of the cam groove. COPYRIGHT: (C)2004,JPO&NCIPI
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