US3721492A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electromagnetic shutter release for continuous operation and single-frame operation in motion picture cameras
Assignee: Ernst Leitz Wetzlar GmbH
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Filing: 1972-03-01
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Granted: 1973-03-20
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Expires: 1992-03-01
Abstract
Abstract A MOTION PICTURE CAMERA WHEREIN THE ROTATING SHUTTER AND THE FILM ADVACE MECHANISM ARE DRIVEN BY AN ELECTRIC MOTOR FOR OPTIONALLY RELEASING THE SHUTTER FOR CONTINUOUS OPERATION OR FOR SINGLE FRAME EXPOSURE. A BI-STABLE CIRCUIT IS PROVIDED IN SERIES WITH THE CAMERA RELEASE SWITCH, THE CIRCUIT BEING SWITCHED TO ITS CONDUCTIVE STATE WHEN THE CAMERA RELEASE SWITCH IS CLOSED. THE BISTABLE CIRCUIT CONTROLS A SOLENOID WHICH RELEASES THE SHUTTER FOR ROTATION WHEN THE BISTABLE CIRCUIT IS CONDUCTIVE. A SERIES OF CAMS ON THE SHUTTER SHAFT OPERATES A SERIES OF SWITCHES FOR CONTROLLING THE BISTABLE CIRCUIT AND THE SOLENOID TO SECURE EITHER CONTINUOUS OPERATION OR TIME EXPOSURES.
Inventors
- 👤 A Kessler
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 15:02
CPC Classifications
G; G03; G03B; G03B19/00; G03B19/18
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-03-19 | 1976-09-18 | 1977-03-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-03-19 | 1980-09-18 | 1981-03-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-03-19 | 1984-09-18 | 1985-03-20 | $7700.00 | Window Closed / Lapsed |