Patent US4703570A successfully refreshed from Google Patents.
US4048641A
Expired / Lapsed
US
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Mechanism to open and close iris on lens
Assignee: AB Dick Co
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Filing: 1976-06-14
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Granted: 1977-09-13
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Expires: 1996-06-14
Abstract
Abstract Some photocomposition machines use optics with a variable magnification lens, usually referred to as a variator lens. Because larger size print requires more lumens of power for proper exposure of the photosensitive sheets used in photocomposition machines, the common practice is to employ an iris diaphragm which is coordinated with the size of the projected image. The ratio of the diaphragm opening to the focal length is referred to as the f-number. The invention shows an improved cam operated iris control wherein the cam-to-follower pressure angle is maintained at a minimum and provides a means for enabling the cam follower to traverse the entire cam without binding as the cam follower carriage is moved relative to the driving cam.
Inventors
- 👤 Robert J. Cieplik
- 👤 Victor Czarnecki
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 16:12
CPC Classifications
B; B41; B41B; B41B21/00; B41B21/16; G; G02; G02B; G02B7/00; G02B7/02; G02B7/04
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
251 words
A cam and cam follower lens system, comprising: a lens, an iris diaphragm that can be turned by a ring so as to change the diameter of a central opening, said diaphragm and lens mounted on a carriage in juxtaposition whereby the diaphragm effectively controls the aperture of the lens; an iris diaphragm ring having a drive receiving gear configuration, an idler gear engaged with said diaphragm gear; a follower arm having a first end which is a gear segment and a second end which is a cam follower wheel, a means for pivotally mounting said arm with the gear segment engaged with said idler gear; a cam track means for driving said follower arm and iris diaphragm to a predetermined aperture opening by moving said carriage along a path paralleling said cam track, said cam track means consisting of a pair of surfaces, one of said surfaces being a generated cam surface and the other being a confining surface, said surfaces closely spaced to a clearance of about 0.08 mm with respect to said follower wheel throughout a calculated f-number range wherein the pressure angle of the cam surface and wheel is not greater than 40°, said other one of said spaced surfaces diverging to release said wheel in areas wherein an abrupt change of cam slope would otherwise result in a binding of the wheel, and means for engaging said follower wheel end to apply pressure to hold said wheel against the cam surface only in said released area.
Claim 2
Dependent Claim
251 words
A cam and cam follower lens system, comprising: a lens, an iris diaphragm that can be turned by a ring so as to change the diameter of a central opening, said diaphragm and lens mounted on a carriage in juxtaposition whereby the diaphragm effectively controls the aperture of the lens; an iris diaphragm ring having a drive receiving gear configuration, an idler gear engaged with said diaphragm gear; a follower arm having a first end which is a gear segment and a second end which is a cam follower wheel, a means for pivotally mounting said arm with the gear segment engaged with said idler gear; a cam track means for driving said follower arm and iris diaphragm to a predetermined aperture opening by moving said carriage along a path paralleling said cam track, said cam track means consisting of a pair of surfaces, one of said surfaces being a generated cam surface and the other being a confining surface, said surfaces closely spaced to a clearance of about 0.08 mm with respect to said follower wheel throughout a calculated f-number range wherein the pressure angle of the cam surface and wheel is not greater than 40°, said other one of said spaced surfaces diverging to release said wheel in areas wherein an abrupt change of cam slope would otherwise result in a binding of the wheel, and means for engaging said follower wheel end to apply pressure to hold said wheel against the cam surface only in said released area.
Claim 3
Dependent Claim
157 words
A cam and cam follower lens system, comprising: a lens, an iris diaphragm that can be turned by a ring so as to change the diameter of a cnetral opening, said diaphragm and lens mounted on a carriage in juxtaposition whereby the diaphragm effectively controls the aperture of the lens; way rods defining a carriage track and means mounting said carriage for longitudinal movement on said track; said iris diaphragm ring having a drive receiving gear configuration, an idler gear engaged with said diaphragm gear; a follower arm having a first end which is a gear segment and a second end which is a cam follower wheel, a means for pivotally mounting said arm with the gear segment engaged with said idler gear; a cam plate extending parallel to said track, said plate having a guide slot which captures said wheel loosely held, said slot and wheel limited to a pressure angle of not more than 40°.
Claim 4
Dependent Claim
157 words
A cam and cam follower lens system, comprising: a lens, an iris diaphragm that can be turned by a ring so as to change the diameter of a cnetral opening, said diaphragm and lens mounted on a carriage in juxtaposition whereby the diaphragm effectively controls the aperture of the lens; way rods defining a carriage track and means mounting said carriage for longitudinal movement on said track; said iris diaphragm ring having a drive receiving gear configuration, an idler gear engaged with said diaphragm gear; a follower arm having a first end which is a gear segment and a second end which is a cam follower wheel, a means for pivotally mounting said arm with the gear segment engaged with said idler gear; a cam plate extending parallel to said track, said plate having a guide slot which captures said wheel loosely held, said slot and wheel limited to a pressure angle of not more than 40°.
Claim 5
Dependent Claim
84 words
The auto-focus lens system of claim 2 wherein the follower arm is a composite of the gear segment as one unit and the cam follower wheel as a separate segment, the composite members mounted on a common pivot, and means to bind the segments together in adjustably selected angular relationship about the pivot, whereby the iris diaphragm is adjusted by loosening the members and adjusting the iris opening by rotating the gear train with the follower arm remaining captured in the cam guide slot.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-09-12 | 1981-03-14 | 1981-09-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-09-12 | 1985-03-14 | 1985-09-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-09-12 | 1989-03-14 | 1989-09-13 | $7700.00 | Window Closed / Lapsed |