US2071806A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Air filter for ventilating systems or apparatus
Assignee: UNIVERSAL AIR FILTER Corp
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Filing: 1936-04-06
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Granted: 1937-02-23
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Expires: 1956-04-06
Abstract
No abstract record available.
Inventors
- 👤 Russell S Walker
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 19:53
CPC Classifications
B; B01; B01D; B01D46/00; B01D46/52; B01D46/521; B01D46/523; B01D46/0002; B01D46/0005; B01D46/10
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1940-02-23 | 1940-08-24 | 1941-02-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1944-02-23 | 1944-08-24 | 1945-02-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1948-02-23 | 1948-08-24 | 1949-02-23 | $7700.00 | Window Closed / Lapsed |