Patent US2937560A successfully refreshed from Google Patents.
US2937560A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Optical square
Assignee: Keuffel and Esser Co
•
Filing: 1955-05-05
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Granted: 1960-05-24
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Expires: 1975-05-05
Abstract
No abstract record available.
Inventors
- 👤 Eugene V Mades
- 👤 Allister L Baker
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 18:30
CPC Classifications
G; G02; G02B; G02B23/00; G02B23/14
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
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US1722209A
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US1012715A
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US1744994A
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DE504783C
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FR726535A
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FR800097A
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GB509279A
Cited
US2285768A
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US2481551A
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US2573703A
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US2692527A
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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) | 1963-05-24 | 1963-11-23 | 1964-05-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1967-05-24 | 1967-11-23 | 1968-05-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1971-05-24 | 1971-11-23 | 1972-05-24 | $7700.00 | Window Closed / Lapsed |