Patent US2640558A successfully refreshed from Google Patents.
US2640558A
Expired / Lapsed
US
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Air purifying and circulating device
Assignee: W B CONNOR ENGINEERING CORP
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Filing: 1949-07-23
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Granted: 1953-06-02
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Expires: 1969-07-23
Abstract
No abstract record available.
Inventors
- 👤 George S Dauphinee
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 14:15
CPC Classifications
F; F25; F25D; F25D17/00; F25D17/04; F25D17/042
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US860465A
Cited
GB227343A
Cited
US1714854A
Cited
US1865538A
Cited
US2265317A
Cited
US2303333A
Cited
US2440487A
Cited
US2420707A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1956-06-01 | 1956-12-01 | 1957-06-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1960-06-01 | 1960-12-01 | 1961-06-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1964-06-01 | 1964-12-01 | 1965-06-02 | $7700.00 | Window Closed / Lapsed |