Patent US2753831A successfully refreshed from Google Patents.
US2753831A
Expired / Lapsed
US
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Air filter clogging warning apparatus
Assignee: Individual
•
Filing: 1952-05-10
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Granted: 1956-07-10
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Expires: 1972-05-10
Abstract
No abstract record available.
Inventors
- 👤 Walter B Davies
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 22:51
CPC Classifications
B; B01; B01D; B01D46/00; B01D46/10; F; F24; F24F; F24F13/00; F24F13/28; G; G08; G08B; G08B21/00; G08B21/18; Y; Y10; Y10S; Y10S116/00; Y10S116/42; Y10S55/00; Y10S55/34
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
NL42636C
Cited
US1770094A
Cited
GB345440A
Cited
US1926688A
Cited
US2230113A
Cited
US2629572A
Cited
US2682250A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1959-07-10 | 1960-01-09 | 1960-07-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1963-07-10 | 1964-01-09 | 1964-07-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1967-07-10 | 1968-01-09 | 1968-07-10 | $7700.00 | Window Closed / Lapsed |