Patent US4539398A successfully refreshed from Google Patents.
Patent US2640392A successfully refreshed from Google Patents.
US2640392A
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US
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Apparatus for measuring the focal length of lenses
Assignee: Individual
•
Filing: 1949-01-27
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Granted: 1953-06-02
•
Expires: 1969-01-27
Abstract
No abstract record available.
Inventors
- 👤 Freeman Hyman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 07:23
CPC Classifications
G; G01; G01M; G01M11/00; G01M11/02; G01M11/0228
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
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US1083309A
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US1241612A
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US1164795A
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US1608725A
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US1706096A
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US1894910A
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US2111580A
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US2042565A
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GB591991A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1956-06-01 | 1956-12-01 | 1957-06-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1960-06-01 | 1960-12-01 | 1961-06-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1964-06-01 | 1964-12-01 | 1965-06-02 | $7700.00 | Window Closed / Lapsed |