US2881920A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Settler with paddle
Assignee: Shell Development Co
•
Filing: 1956-06-11
•
Granted: 1959-04-14
•
Expires: 1976-06-11
Abstract
No abstract record available.
Inventors
- 👤 Donald J Simkin
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 21:46
CPC Classifications
B; B01; B01D; B01D17/00; B01D17/02; B01D17/0208; B01D17/0214; B01D17/04; B01D17/041
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US1297171A
Cited
FR642586A
Cited
US2121324A
Cited
US2143441A
Cited
US2672406A
Cited
US2729549A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1962-04-13 | 1962-10-13 | 1963-04-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1966-04-13 | 1966-10-13 | 1967-04-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1970-04-13 | 1970-10-13 | 1971-04-14 | $7700.00 | Window Closed / Lapsed |