Patent US2642770A successfully refreshed from Google Patents.
US2642770A
Expired / Lapsed
US
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Schlieren apparatus of improved optical quality
Assignee: United States Department of the Air Force
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Filing: 1950-07-25
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Granted: 1953-06-23
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Expires: 1970-07-25
Abstract
No abstract record available.
Inventors
- 👤 Theodor W Zobel
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 20:04
CPC Classifications
G; G02; G02B; G02B27/00; G02B27/50; G02B27/54
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US1915204A
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US1969037A
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US1698905A
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US1794103A
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GB400445A
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US1963128A
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US2081299A
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FR888644A
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US2312888A
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US2362235A
Cited
US2425758A
Cited
US2541437A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1956-06-22 | 1956-12-22 | 1957-06-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1960-06-22 | 1960-12-22 | 1961-06-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1964-06-22 | 1964-12-22 | 1965-06-23 | $7700.00 | Window Closed / Lapsed |