Patent US3702728A successfully refreshed from Google Patents.
US3702728A
Expired / Lapsed
US
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Automatic switching arrangement for motion picture film projectors
Assignee: Agfa Gevaert AG
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Filing: 1970-12-18
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Granted: 1972-11-14
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Expires: 1990-12-18
Abstract
Abstract THE VARYING INTENSITY OF THE LIGHT PASSING THROUGH THE EXPOSED PORTION OF A FILM CAUSES A CONSTANTLY CHANGING VOLTAGE IN A CIRCUIT HAVING A PHOTOSENSITIVE ELEMENT, SUCH AS A PHOTOTRANSISTOR. THIS VARYING VOLTAGE OPERATES A THRESHOLE SWITCH, SUCH AS A THYRISTOR, TO SWITCH THE PROJECTOR AUTOMATICALLY FROM HIGH THREADING SPEED TO PROJECTION SPEED.
Inventors
- 👤 Alfred Winkler
- 👤 Eduard Wagensonner
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 23:15
CPC Classifications
G; G03; G03B; G03B19/00; G03B19/18; G03B21/00; G03B21/14; G03B21/32; G03B21/43
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) | 1975-11-14 | 1976-05-15 | 1976-11-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-11-14 | 1980-05-15 | 1980-11-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-11-14 | 1984-05-15 | 1984-11-14 | $7700.00 | Window Closed / Lapsed |