Patent US3641899A successfully refreshed from Google Patents.
US3641899A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Device for preventing double-exposures in interchangeable film back-type cameras
Assignee: Nikon Corp
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Filing: 1969-10-29
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Granted: 1972-02-15
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Expires: 1989-10-29
Abstract
Abstract Upon attachment of a film back having an exposed but unwound film to a camera body its shutter charged, a shutter release button is automatically locked so as to prevent the doubleexposure during the film advancement, after which the shutter release button is automatically set free. Thereafter, the device is automatically disconnected from the shutter charging mechanism which also advances the film, so that the shutter may be charged and the film may be advanced in a normal manner.
Inventors
- 👤 Tomio Tsuruoka
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 22:09
CPC Classifications
G; G03; G03B; G03B17/00; G03B17/26; G03B17/42
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
300 words
A double-exposure prevention device for a camera, having an interchangeable film magaZine forming a portion of the backwall of a camera housing, which comprises: a shutter button positioned on said housing; an operating lever mounted on said housing and adapted to successively wind the film and charge the shutter; a drive shaft rotatably mounted in said magazine and engageable with said operating lever; a ratchet wheel carried by said drive shaft; a detent pawl normally engaging said ratchet; an indexing wheel means positioned in said magazine and being rotated in response to the film-winding operation of said operating lever, said indexing means including a pair of toothed wheels; a signal lever lockably engaging said detent pawl and having a first arm engageable with the teeth of said indexing means and a second arm projecting through said magazine into said camera; a biasing means urging said signal lever toward said indexing means; first and second pivoted levers provided in the camera body and engageable with said second arm of said signal lever, when said magazine is attached to said camera body; said first pivoted lever being moveable in response to shutter operation from a first position to a second position to disengage said signal lever from said indexing wheel means; biasing means urging said second pivoted lever toward said second arm, said second pivoted lever being locked by said second arm when said first pivoted lever is moved to its second position; and a locking lever pivoted with said second pivoted lever, said locking lever being inserted under said shutter button when said signal lever is disengaged from said indexing wheel means to lock said shutter button and being retracted from under said shutter button when said signal lever engages said indexing wheel means to permit actuation of said shutter button.
Claim 2
Dependent Claim
300 words
A double-exposure prevention device for a camera, having an interchangeable film magaZine forming a portion of the backwall of a camera housing, which comprises: a shutter button positioned on said housing; an operating lever mounted on said housing and adapted to successively wind the film and charge the shutter; a drive shaft rotatably mounted in said magazine and engageable with said operating lever; a ratchet wheel carried by said drive shaft; a detent pawl normally engaging said ratchet; an indexing wheel means positioned in said magazine and being rotated in response to the film-winding operation of said operating lever, said indexing means including a pair of toothed wheels; a signal lever lockably engaging said detent pawl and having a first arm engageable with the teeth of said indexing means and a second arm projecting through said magazine into said camera; a biasing means urging said signal lever toward said indexing means; first and second pivoted levers provided in the camera body and engageable with said second arm of said signal lever, when said magazine is attached to said camera body; said first pivoted lever being moveable in response to shutter operation from a first position to a second position to disengage said signal lever from said indexing wheel means; biasing means urging said second pivoted lever toward said second arm, said second pivoted lever being locked by said second arm when said first pivoted lever is moved to its second position; and a locking lever pivoted with said second pivoted lever, said locking lever being inserted under said shutter button when said signal lever is disengaged from said indexing wheel means to lock said shutter button and being retracted from under said shutter button when said signal lever engages said indexing wheel means to permit actuation of said shutter button.
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) | 1975-02-14 | 1975-08-16 | 1976-02-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-02-14 | 1979-08-16 | 1980-02-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-02-14 | 1983-08-16 | 1984-02-15 | $7700.00 | Window Closed / Lapsed |