| 摘要 |
A lens-driving cam mechanism includes a zoom cylinder rotatable about the optical axis of the lens and a zoom cam ring incapable of rotation about the optical axis provided on the peripheral surface of the zoom cylinder. A front cam portion and a rear cam portion are formed on the zoom cylinder. Cam followers which contact with the front cam portion and the rear cam portion are formed on the peripheral surface of the zoom cylinder. When the zoom cylinder rotates, the zoom cam ring is moved along the optical axis by the cooperation of the cam portions and the cam followers. The zoom cam ring has on the inner surface thereof a cam follower-inserting groove for permitting one of the cam followers to pass therethrough so that the zoom cylinder and the zoom cam ring can be assembled.
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