US3659798A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Coil spring slip clutch
Assignee: Eastman Kodak Co
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Filing: 1970-06-05
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Granted: 1972-05-02
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Expires: 1990-06-05
Abstract
Abstract A coil spring slip clutch adapted for use in a roll film camera for advancing a film strip within the camera. The clutch comprises a rotatably mounted cylindrical drive shaft having a smooth surface portion around which the coils of a coil spring are tightly wrapped. One end of the coil spring is bent outwardly so as to drivingly engage a film advancing mechanism when the shaft is rotated. The contacting surfaces of the coil spring and drive shaft are selected from materials which remain in frictional engagement sufficient to cause the coil spring to drive the film advancing mechanism until the retarding force exerted by such mechanism exceeds a critical frictional force characteristic of one of the materials, at which time the coil spring slips relative to the drive shaft.
Inventors
- 👤 Fredric A Mindler
- 👤 Charles E Pickering
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 16:40
CPC Classifications
G; G03; G03B; G03B17/00; G03B17/28; G03B17/30; G03B17/305
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
245 words
A film advancing apparatus for transporting predetermined incremental lengths of film strip in a roll film camera, said apparatus comprising: a housing; a drive shaft rotatably mounted in said housing; a helical spring including (1) coils encircling said drive shaft in a direction to tighten said coils about said shaft when said shaft is rotated in a first direction, said helical spring and said drive shaft being in frictional engagement and having a critical friction force value such that said spring is rotated in said first direction in response to the rotation of said drive shaft in the first direction when the friction force between said spring and said shaft is less than said critical value, and said shaft is rotatable in the first direction relative to said spring when the friction force between said spring and said shaft is equal to or greater than said critical value, and (2) an engageable end portion extending from said coils; and means movable for transporting the film strip, said transporting means being (1) in driven engagement with said spring end portion and movable in response to rotation of said spring in the first direction, and (2) adapted to exert a force on said spring in response to the transportation of a predetermined length of film strip to increase the friction force between said spring and said drive shaft beyond said critical value to limit the amount of film transported by said apparatus to the predetermined incremental length.
Claim 2
Dependent Claim
245 words
A film advancing apparatus for transporting predetermined incremental lengths of film strip in a roll film camera, said apparatus comprising: a housing; a drive shaft rotatably mounted in said housing; a helical spring including (1) coils encircling said drive shaft in a direction to tighten said coils about said shaft when said shaft is rotated in a first direction, said helical spring and said drive shaft being in frictional engagement and having a critical friction force value such that said spring is rotated in said first direction in response to the rotation of said drive shaft in the first direction when the friction force between said spring and said shaft is less than said critical value, and said shaft is rotatable in the first direction relative to said spring when the friction force between said spring and said shaft is equal to or greater than said critical value, and (2) an engageable end portion extending from said coils; and means movable for transporting the film strip, said transporting means being (1) in driven engagement with said spring end portion and movable in response to rotation of said spring in the first direction, and (2) adapted to exert a force on said spring in response to the transportation of a predetermined length of film strip to increase the friction force between said spring and said drive shaft beyond said critical value to limit the amount of film transported by said apparatus to the predetermined incremental length.
Claim 3
Dependent Claim
106 words
Apparatus according to claim 1 wherein: said drive shaft has an external surface engaged with said coils, said surface (1) being in locking frictional engagement with said coils when the friction force between said surface and said coils is less than said critical value, and (2) allowing said coils to slip relative to said surface when the friction force is equal to or greater than said critical value; and the fit of sAid coils on said shaft loosens in response to rotation of said shaft in a second direction opposite to said first direction to permit the free rotation of said shaft relative to said coils.
Claim 4
Dependent Claim
15 words
Apparatus according to claim 2 wherein said surface comprises a layer of copolymer acetal resin.
Claim 5
Dependent Claim
15 words
Apparatus according to claim 2 wherein said surface comprises a layer of homopolymer acetal resin.
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) | 1975-05-02 | 1975-11-01 | 1976-05-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-05-02 | 1979-11-01 | 1980-05-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-05-02 | 1983-11-01 | 1984-05-02 | $7700.00 | Window Closed / Lapsed |