Patent US2220669A successfully refreshed from Google Patents.
US2220669A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Impeller for centrifugal pumps
Assignee: Allen Sherman Hoff Co
•
Filing: 1937-12-06
•
Granted: 1940-11-05
•
Expires: 1957-12-06
Abstract
No abstract record available.
Inventors
- 👤 Frank B Allen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 16:48
CPC Classifications
F; F04; F04D; F04D29/00; F04D29/18; F04D29/22; F04D29/2205; F04D29/2222; F04D29/2227; F05; F05D; F05D2300/00; F05D2300/40; F05D2300/43; F05D2300/431
Claims Analysis
Total Claims: 0
No claims parsed yet. Click Sync Now above to re-index claims from Google Patents.
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) | 1943-11-05 | 1944-05-06 | 1944-11-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1947-11-05 | 1948-05-06 | 1948-11-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1951-11-05 | 1952-05-06 | 1952-11-05 | $7700.00 | Window Closed / Lapsed |