Patent US2770321A successfully refreshed from Google Patents.
US2770321A
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Air filtering apparatus
Assignee: MSA Safety Inc
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Filing: 1954-06-24
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Granted: 1956-11-13
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Expires: 1974-06-24
Abstract
No abstract record available.
Inventors
- 👤 Raymond E Brochetti
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 03:05
CPC Classifications
B; B01; B01D; B01D46/00; B01D46/66; B01D46/74; B01D46/76; B01D46/02; B01D46/026; B01D46/04; B01D46/42; B01D46/4227; B01D46/48; B01D50/00; B01D50/20
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US918895A
Cited
US898426A
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US971215A
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US959936A
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US971013A
Cited
US1856133A
Cited
US1886215A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1959-11-13 | 1960-05-14 | 1960-11-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1963-11-13 | 1964-05-14 | 1964-11-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1967-11-13 | 1968-05-14 | 1968-11-13 | $7700.00 | Window Closed / Lapsed |