Patent US2820907A successfully refreshed from Google Patents.
US2820907A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Microfilm apparatus
Assignee: Individual
•
Filing: 1951-07-27
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Granted: 1958-01-21
•
Expires: 1971-07-27
Abstract
No abstract record available.
Inventors
- 👤 Silverman Daniel
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-22 23:29
CPC Classifications
G; G02; G02B; G02B7/00; G02B7/28; G02B7/36; G03; G03B; G03B17/00; G03B17/24
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
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US1838389A
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US1822902A
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US2011932A
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US2294734A
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US2268499A
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US2282029A
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US2250209A
Cited
US2358051A
Cited
US2563892A
Cited
US2557022A
Cited
US2666356A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1961-01-20 | 1961-07-22 | 1962-01-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1965-01-20 | 1965-07-22 | 1966-01-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1969-01-20 | 1969-07-22 | 1970-01-21 | $7700.00 | Window Closed / Lapsed |