Optical: systems and elements – Lens – With variable magnification
Reexamination Certificate
2000-02-02
2001-10-09
Epps, Georgia (Department: 2873)
Optical: systems and elements
Lens
With variable magnification
C359S703000
Reexamination Certificate
active
06301060
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a lens barrel adapted for an optical apparatus such as a camera or the like, and more particularly to the dust-proof and drip-proof structural arrangement of a lens barrel or the like.
2. Description of Related Art
The rotating parts, such as rotary operation parts, of lens barrels are often arranged to be in a dust-proof and drip-proof structure. Generally, the dust-proof and drip-proof structure is arranged to prevent intrusion of water, dust, etc., by inserting a rubber O-ring in between a body member and a rotating member of the lens barrel.
However, such a dust-proof and drip-proof structural arrangement generates a large frictional force between the O-ring and the rotating member. The large frictional force necessitate exertion of a large force in operating the rotating member. The conventional arrangement thus has often made the rotating member difficult to operate, or has prevented effective utilization of space due to limitation imposed on the diameter of the O-ring.
BRIEF SUMMARY OF THE INVENTION
It is an object of the invention to provide a lens barrel which is arranged to adequately maintain a good water-proof effect and yet to excel in operability.
To attain the above object, in accordance with an aspect of the invention, there is provided a lens barrel which comprises fixed tubes each arranged to hold an optical unit having an optical axis, a rotating tube arranged to rotate around the optical axis with respect to the fixed tubes, wherein the rotating tube is provided, at front and rear portions thereof as viewed along the optical axis, respectively with end surfaces of ring shape having a center thereof on the optical axis, and each of the fixed tubes is provided with an end surface opposite to the associated end surface of the rotating tube, and sheet members of ring shape having a center thereof on the optical axis, each of the sheet members being disposed on a space formed by each end surface of the rotating tube and the associated end surface of the fixed tubes.
Further, in the lens barrel, a wave washer of ring shape having a center thereof on the optical axis, and having convex portions and concave portions as viewed along the optical axis, is disposed in the space.
Further, the rotating tube is a manual operation ring arranged to be manually rotated to move another optical unit along the optical axis.
Further, each of the fixed tubes has a sliding surface arranged to restrict movement of the rotating tube along the optical axis and to allow the rotating tube to rotate thereon, and a water-repellant agent is applied to the sliding surface.
Further, the sheet members are made of plastic material.
Further, the sheet members are made of vinyl chloride material.
The above and other objects and features of the invention will become apparent from the following detailed description of preferred embodiments thereof taken in connection with the accompanying drawings.
REFERENCES:
patent: 6024457 (2000-02-01), Kawai et al.
Ishikawa Masanori
Sato Tatsuya
Shinohara Mitsuru
Watanabe Takashi
Canon Kabushiki Kaisha
Epps Georgia
Robin, Blecker & Dale
Seyrafi Saeed
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