Patent US2668684A successfully refreshed from Google Patents.
US2668684A
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US
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Dustproof damper
Assignee: Individual
•
Filing: 1949-06-18
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Granted: 1954-02-09
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Expires: 1969-06-18
Abstract
No abstract record available.
Inventors
- 👤 Walter F Metzger
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 23:36
CPC Classifications
F; F16; F16K; F16K13/00; F16K13/02
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US344088A
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US720428A
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US738001A
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US1066978A
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GB191500502A
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US1424624A
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CH95535A
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US1667959A
Cited
DE511268C
Cited
US2142236A
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US2222280A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1957-02-08 | 1957-08-10 | 1958-02-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1961-02-08 | 1961-08-10 | 1962-02-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1965-02-08 | 1965-08-10 | 1966-02-09 | $7700.00 | Window Closed / Lapsed |