Patent US2566889A successfully refreshed from Google Patents.
US2566889A
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US
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Variable magnification optical system
Assignee: W Watson and Sons Ltd
•
Filing: 1948-10-22
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Granted: 1951-09-04
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Expires: 1968-10-22
Abstract
No abstract record available.
Inventors
- 👤 Hopkins Harold Horace
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 23:11
CPC Classifications
G; G02; G02B; G02B15/00; G02B15/14; G02B15/144; G02B15/1445; G02B15/144507
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US696788A
Cited
US1988390A
Cited
US1950166A
Cited
US1947669A
Cited
US2235364A
Cited
US2184018A
Cited
US2271227A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1954-09-03 | 1955-03-05 | 1955-09-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1958-09-03 | 1959-03-05 | 1959-09-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1962-09-03 | 1963-03-05 | 1963-09-04 | $7700.00 | Window Closed / Lapsed |