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US2830302A
Expired / Lapsed
US
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Flapper valve
Assignee: Crane Co
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Filing: 1956-02-07
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Granted: 1958-04-15
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Expires: 1976-02-07
Abstract
No abstract record available.
Inventors
- 👤 Axel B Nelson
- 👤 Edward G Schmidt
- 👤 Roy H Zinkil
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 16:12
CPC Classifications
E; E03; E03D; E03D1/00; E03D1/30; E03D1/34; E03D1/304; E03D1/306
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1961-04-14 | 1961-10-14 | 1962-04-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1965-04-14 | 1965-10-14 | 1966-04-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1969-04-14 | 1969-10-14 | 1970-04-15 | $7700.00 | Window Closed / Lapsed |