| 摘要 |
PROBLEM TO BE SOLVED: To provide a zoom lens barrel capable of surely preventing the disengagement of a cam groove and a cam follower in the case an external force is applied on a frame member for holding a lens. SOLUTION: The lens barrel 10 is provided with a rotary frame 2 which is driven so as to rotate, and a zoom frame 3 which is driven backward and forward by the cam grooves 2a and 2b of the rotary frame 2 in a rotation- controlled state. The cam grooves 2a and 2b are separately arranged in three divided rotational extents in the inner periphery of the rotary frame 2, and three pairs of cam followers 15 and 16 are inserted while shifting the phase. As for the cam grooves 2a and 2b, tapered wall surfaces with vertical wall surfaces 2a3 and 2b3 for receiving the external force in the optical axis direction are formed in a first area of the rotating extent, and only the tapered wall surface is formed in a second area of the rotating extent. At least either of the cam followers 15 and 16 comes into contact with the vertical wall surface 2a3 or 2b3 in the whole driving extent of the cam grooves 2a and 2b so as to receive the external force to be applied on the zoom frame 3.
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