Patent US3393523A successfully refreshed from Google Patents.
US3393523A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Tunnel lining unit
Assignee: Individual
•
Filing: 1967-02-14
•
Granted: 1968-07-23
•
Expires: 1987-02-14
Abstract
No abstract record available.
Inventors
- 👤 Krivda Alfred
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 03:28
CPC Classifications
E; E21; E21D; E21D11/00; E21D11/14; E21D11/15
Claims Analysis
Total Claims: 0
No claims parsed yet. Click Sync Now above to re-index claims from Google Patents.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1971-07-23 | 1972-01-22 | 1972-07-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1975-07-23 | 1976-01-22 | 1976-07-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1979-07-23 | 1980-01-22 | 1980-07-23 | $7700.00 | Window Closed / Lapsed |