US2981141A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Optical compensator and tilt detector
Assignee: Hilger and Watts Ltd
•
Filing: 1958-01-16
•
Granted: 1961-04-25
•
Expires: 1978-01-16
Abstract
No abstract record available.
Inventors
- 👤 Armstrong John Argent
- 👤 Berry Douglas William
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 21:51
CPC Classifications
G; G02; G02B; G02B27/00; G02B27/64; G02B27/646; G02B27/648
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US1722209A
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DE548685C
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US994061A
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DE346908C
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US1552449A
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DE550075C
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US2406798A
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US2410667A
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US2386621A
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US2533686A
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US2779231A
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AT178209B
Cited
US2741940A
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US2855818A
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US2843001A
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1964-04-24 | 1964-10-24 | 1965-04-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1968-04-24 | 1968-10-24 | 1969-04-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1972-04-24 | 1972-10-24 | 1973-04-25 | $7700.00 | Window Closed / Lapsed |