Patent US2991692A successfully refreshed from Google Patents.
US2991692A
Expired / Lapsed
US
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Filter devices for enlarging apparatus
Assignee: Kamera und Kinowerke Dresden VEB
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Filing: 1957-11-15
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Granted: 1961-07-11
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Expires: 1977-11-15
Abstract
No abstract record available.
Inventors
- 👤 Korf Erich
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 13:54
CPC Classifications
G; G03; G03B; G03B27/00; G03B27/72
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
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US1398952A
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US1878857A
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US727524A
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US1024242A
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US1127763A
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US1721411A
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US1766637A
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US1887654A
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US2291347A
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US2460507A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1964-07-10 | 1965-01-09 | 1965-07-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1968-07-10 | 1969-01-09 | 1969-07-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1972-07-10 | 1973-01-09 | 1973-07-11 | $7700.00 | Window Closed / Lapsed |