| 摘要 |
An apparatus for driving a photographic zoom lens in which at least a first and second lens group are disposed on the same optical axis and wherein the apparatus makes it possible to rapidly perform a zooming operation for changing a focal length of the photographic zoom lens. The apparatus comprises a fixed frame and a body tube frame supported within the fixed frame so as to be capable of moving along the optical axis. The apparatus further comprises a first group frame supporting a first lens group, a zooming cam, and a second group frame fixedly supporting a second lens group. Additionally, the apparatus includes a first group driving screw having a first multiple thread screw on a circumferential surface thereof, and adapted to be driven through a first group driving gear and a transmission gear; and a body tube frame driving screw having a second multiple thread screw, and adapted to be driven through a body tube frame driving gear and the transmission gear. The apparatus of the present invention makes it possible to rapidly perform a zooming operation and a housing operation when the power of a driving source and the radius of a driving screw are fixed.
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