Patent US4892538A successfully refreshed from Google Patents.
US1897947A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Fan structure
Assignee: Bell and Howell Co
•
Filing: 1928-11-10
•
Granted: 1933-02-14
•
Expires: 1948-11-10
Abstract
No abstract record available.
Inventors
- 👤 Albert S Howell
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 23:49
CPC Classifications
F; F04; F04D; F04D29/00; F04D29/26; F04D29/28; F04D29/281; Y; Y10; Y10T; Y10T29/00; Y10T29/49; Y10T29/49316; Y10T29/49329
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) | 1936-02-14 | 1936-08-15 | 1937-02-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1940-02-14 | 1940-08-15 | 1941-02-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1944-02-14 | 1944-08-15 | 1945-02-14 | $7700.00 | Window Closed / Lapsed |