US2576581A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Polyfocal spectacles
Assignee: Individual
•
Filing: 1946-07-09
•
Granted: 1951-11-27
•
Expires: 1966-07-09
Abstract
No abstract record available.
Inventors
- 👤 Benjamin F Edwards
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-22 22:19
CPC Classifications
G; G02; G02B; G02B3/00; G02B3/12; G02B3/14; G02C; G02C7/00; G02C7/02; G02C7/08; G02C7/081; G02C7/085
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US968401A
Cited
FR435332A
Cited
US1269422A
Cited
US1515389A
Cited
GB258325A
Cited
FR622615A
Cited
FR757055A
Cited
GB466034A
Cited
FR840622A
Cited
CH241951A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1954-11-26 | 1955-05-28 | 1955-11-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1958-11-26 | 1959-05-28 | 1959-11-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1962-11-26 | 1963-05-28 | 1963-11-27 | $7700.00 | Window Closed / Lapsed |