Patent US2289575A successfully refreshed from Google Patents.
US2289575A
Expired / Lapsed
US
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Illuminating device for instruments
Assignee: SPENCER LENS CO
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Filing: 1940-05-01
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Granted: 1942-07-14
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Expires: 1960-05-01
Abstract
No abstract record available.
Inventors
- 👤 David I Critoph
- 👤 Henry S Schrader
- 👤 Kennard W Harper
- 👤 Oscar W Richards
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 19:53
CPC Classifications
G; G02; G02B; G02B21/00; G02B21/06
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1945-07-13 | 1946-01-12 | 1946-07-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1949-07-13 | 1950-01-12 | 1950-07-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1953-07-13 | 1954-01-12 | 1954-07-14 | $7700.00 | Window Closed / Lapsed |