Patent US2844216A successfully refreshed from Google Patents.
US2844216A
Expired / Lapsed
US
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Air filtering apparatus
Assignee: Day Co
•
Filing: 1956-04-02
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Granted: 1958-07-22
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Expires: 1976-04-02
Abstract
No abstract record available.
Inventors
- 👤 Arden E Swanson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 14:25
CPC Classifications
B; B01; B01D; B01D46/00; B01D46/02; B01D46/04; B01D46/42; B01D46/4272; B01D46/66; B01D46/70; F; F24; F24F; F24F8/00; F24F8/10; F24F8/108; B01D2271/00; B01D2271/02; B01D2271/022; Y; Y10; Y10T; Y10T74/00; Y10T74/11; Y10T74/18; Y10T74/18048; Y10T74/18056; Y10T74/18176
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) | 1961-07-21 | 1962-01-20 | 1962-07-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1965-07-21 | 1966-01-20 | 1966-07-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1969-07-21 | 1970-01-20 | 1970-07-22 | $7700.00 | Window Closed / Lapsed |