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US 4,789,225 AGranted
Device for driving a lens unit having a tripod mount
AssigneeAsahi Kogaku Kogyo Kabushiki Kaisha
InventorHiroshi Nomura
Life of this patent
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Abstract
A drive mechanism for a lens unit with a tripod mount. The tripod mount is on a stationary cylinder while the camera mount is on a rotatable cylinder which contains a drive shaft for mechanically driving a lens axially movable along the stationary cylinder. A drive gear supported by the stationary cylinder causes the linear movement of lens by its rotation. A planetary gear system, coupled to the stationary cylinder connects the drive shaft and the drive gear.
Claims8
A device for driving a lens unit having a tripod mount, comprising:
- a stationary cylinder having said tripod mount;
- a rotatable cylinder with a mount part which is coupled to a camera body rotatably fitted in said stationary cylinder;
- a drive shaft rotatable by a drive source provided on a side of said camera body and rotatably supported in said rotatable cylinder;
- a drive gear which rotates around an optical axis of said lens unit which is supported by said stationary cylinder,;
- a lens which is moved in the direction of said optical axis as said drive gear rotates and which is supported by said stationary cylinder;
- and
- a planet gear mechanism interposed between said drive gear and a gear mounted on said drive shaft, said planet gear mechanism transmitting a first rotation of said drive shaft to said drive gear when said rotatable cylinder is stationary but not transmitting a second rotation of said drive shaft when said drive shaft is revolved by rotation of said rotatable cylinder.
4 more elements
Dependencies are inferred from the claim text.