Optical: systems and elements – Lens – With support
Reexamination Certificate
2000-03-27
2001-11-27
Mack, Ricky (Department: 2873)
Optical: systems and elements
Lens
With support
C359S704000, C359S700000
Reexamination Certificate
active
06324022
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a lens barrel, and in particular, to a lens barrel having a rotatable cylindrical ring with a curvilinear cam groove or slot and a stationary cylindrical ring with a linear cam groove or slot which are arranged coaxially with each other and a lens holder with a cam follower pin in engagement with both curvilinear cam groove and linear cam groove so as to move linearly along the linear grooved cam following movement of the curvilinear grooved cam when rotating either one of the rotatable cylindrical rings relative to the other.
2. Description of the Related Art
Typically, there are numerous lens barrel s that drive optical lens elements, such as a zooming lens element and a focusing lens element, by an manually operated ring or a motor driven ring. Such a lens barrel comprises at least a cylindrical ring with a linear cam groove or slot (which is referred to as a cylindrical linear cam ring) in which lens holders holding focusing lens elements or zooming lens elements is installed and a cylindrical ring with a curvilinear cam groove or slot (which is referred to as a cylindrical curvilinear cam ring) that is fitted externally on and coaxialy with the inner cylindrical ring. These cylindrical cam rings are configured such that either one of the cylindrical cam rings rotates relatively to the other. The lens holder is provided with a cam follower pin which extends radially into the curvilinear cam groove of the cylindrical curvilinear cam ring passing through the linear cam slot of the cylindrical linear cam ring. The lens barrel thus constructed moves the lens holders in an axial direction following rotation of either the cylindrical linear cam ring or the cylindrical curvilinear cam ring.
The this type of lens barrel restricts these cylindrical cam rings in axial position relative to a stationary cylindrical ring of the lens barrel by means of a restrictive ring or a restrictive plate while allowing them to rotate about the optical axis. This construction of the lens barrel has a drawback in an increase in cost that is induced by a large number of parts and an increased man-hour for assembling the lens barrel.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide an optical scanning device which is accurate in scanning operation.
It is another object of the present invention to provide a lens barrel which provide a reduction in the number of parts and man-hour for assembly with an effect of reducing production costs.
The foregoing objects of the present invention are accomplished by a lens barrel that comprises an inner cam barrel, an outer cam barrel disposed coaxially with the inner cam barrel so as to be rotatable relatively to the inner cam barrel, a lens holder for holding a lens element of the optical lens system which has a radial cam follower pin which passes through an inner cam slot of the inner cam barrel and is received in an outer cam slot of the outer cam barrel and is shiftable alongside both inner and outer cam slots in an axial direction following relative rotation between the inner and outer cam barrels so as thereby to cause axial movement of the lens element for adjusting optical operating condition of the optical lens system, and axial movement restraint means for restraining the inner and outer cam barrels from axially moving relatively to each other during relative rotation between the inner and outer cam barrels. The axial movement restraint means comprises a peripheral groove which is formed on either one of the inner and outer cam barrels and a radial jaw which is formed on the other one of the inner and outer cam barrels and received in the peripheral groove for contact slide movement. The axial movement restraint means further comprises elastic means disposed between the inner and outer cam barrels for forcing the inner and outer cam barrels in opposite axial directions so as thereby to press the axial jaw against a wall of the peripheral groove.
Because of the simple structure of the axial movement restraint means which is formed by the jaw and the groove only and, if necessary, the elastic member incorporated between the cam barrels which eliminates axial play usually occurring between the cam barrels, while the number of parts necessary for the lens barrel is reduced and, in consequence, man-hour necessary for assembling the lens barrel is considerably cut, which are always desirable for cutting production costs of the lens barrel, the lens barrel is precise in operation, as compared with conventional lens barrels.
REFERENCES:
patent: 5285322 (1994-02-01), Horning et al.
patent: 6108146 (2000-08-01), Kenin et al.
patent: 6160670 (2000-12-01), Nakayama et al.
patent: 6163412 (2000-12-01), Onda
patent: 6195211 (2001-02-01), Iwasaki
Fuji Photo Optical Co., Ltd.
Mack Ricky
Young & Thompson
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