Patent US2497581A successfully refreshed from Google Patents.
US2497581A
Expired / Lapsed
US
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Vacuum cleaner dust bag unloader
Assignee: Individual
•
Filing: 1945-10-17
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Granted: 1950-02-14
•
Expires: 1965-10-17
Abstract
No abstract record available.
Inventors
- 👤 Jr Charles Kepler Brown
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 11:24
CPC Classifications
A; A47; A47L; A47L9/00; A47L9/20
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
GB270493A
Cited
US1855672A
Cited
US2022249A
Cited
US2041401A
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US2084492A
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US2222077A
Cited
US2272394A
Cited
US2286421A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1953-02-13 | 1953-08-15 | 1954-02-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1957-02-13 | 1957-08-15 | 1958-02-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1961-02-13 | 1961-08-15 | 1962-02-14 | $7700.00 | Window Closed / Lapsed |