Patent US3521973A successfully refreshed from Google Patents.
US3521973A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Fan construction
Assignee: Anpol Research Corp
•
Filing: 1968-08-16
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Granted: 1970-07-28
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Expires: 1988-08-16
Abstract
No abstract record available.
Inventors
- 👤 Arthur C Schouw
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 14:19
CPC Classifications
F; F04; F04D; F04D29/00; F04D29/02; F04D29/023; F04D29/26; F04D29/28; F04D29/281; F05; F05D; F05D2260/00; F05D2260/95; F05D2300/00; F05D2300/40; F05D2300/44; Y; Y10; Y10T; Y10T29/00; Y10T29/49; Y10T29/49316; Y10T29/49329
Claims Analysis
Total Claims: 0
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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) | 1973-07-27 | 1974-01-26 | 1974-07-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1977-07-27 | 1978-01-26 | 1978-07-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1981-07-27 | 1982-01-26 | 1982-07-28 | $7700.00 | Window Closed / Lapsed |