Patent US2456711A successfully refreshed from Google Patents.
US2456711A
Expired / Lapsed
US
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Adjustable condenser lens for projection systems
Assignee: Bell and Howell Co
•
Filing: 1947-03-14
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Granted: 1948-12-21
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Expires: 1967-03-14
Abstract
No abstract record available.
Inventors
- 👤 Norman T Knutson
- 👤 Paul C Foote
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 10:59
CPC Classifications
G; G03; G03B; G03B21/00; G03B21/14; G03B21/20; G03B21/208
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US297851A
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US780590A
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US1118187A
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US1338818A
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US1540340A
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US1527883A
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US1932701A
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US2169010A
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US2231743A
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US2292966A
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US2425863A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1951-12-21 | 1952-06-21 | 1952-12-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1955-12-21 | 1956-06-21 | 1956-12-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1959-12-21 | 1960-06-21 | 1960-12-21 | $7700.00 | Window Closed / Lapsed |