Patent US2682250A successfully refreshed from Google Patents.
US2682250A
Expired / Lapsed
US
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Air filter signal
Assignee: Individual
•
Filing: 1950-04-25
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Granted: 1954-06-29
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Expires: 1970-04-25
Abstract
No abstract record available.
Inventors
- 👤 Roy E Ulrich
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 18:46
CPC Classifications
F; F24; F24F; F24F13/00; F24F13/28; A; A47; A47L; A47L9/00; A47L9/10; A47L9/19; Y; Y10; Y10S; Y10S55/00; Y10S55/34
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US471015A
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US1558934A
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US992487A
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US976008A
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FR421030A
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US1397263A
Cited
US1779795A
Cited
US1811853A
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US2172399A
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US2270318A
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US2507934A
Cited
US2485142A
Cited
US2493164A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1957-06-28 | 1957-12-28 | 1958-06-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1961-06-28 | 1961-12-28 | 1962-06-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1965-06-28 | 1965-12-28 | 1966-06-29 | $7700.00 | Window Closed / Lapsed |