Patent US2463723A successfully refreshed from Google Patents.
US2463723A
Expired / Lapsed
US
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Air filter
Assignee: Individual
•
Filing: 1944-11-28
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Granted: 1949-03-08
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Expires: 1964-11-28
Abstract
No abstract record available.
Inventors
- 👤 Spraragen Louis
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 18:09
CPC Classifications
F; F02; F02M; F02M35/00; F02M35/02; F02M35/08
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US741210A
Cited
US1212450A
Cited
US1387731A
Cited
US1814855A
Cited
US1822471A
Cited
US2016991A
Cited
US1982639A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1952-03-07 | 1952-09-06 | 1953-03-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1956-03-07 | 1956-09-06 | 1957-03-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1960-03-07 | 1960-09-06 | 1961-03-08 | $7700.00 | Window Closed / Lapsed |