US52672A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Improvement in lenses
Assignee: —
•
Filing: —
•
Granted: 1866-02-20
•
Expires: 1883-02-20
Abstract
No abstract record available.
Inventors
No inventors recorded.
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 21:37
CPC Classifications
G; G02; G02B; G02B13/00
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) | 1869-02-19 | 1869-08-21 | 1870-02-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1873-02-19 | 1873-08-21 | 1874-02-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1877-02-19 | 1877-08-21 | 1878-02-20 | $7700.00 | Window Closed / Lapsed |