US3486528A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Vent valve having dynamic valve opening structure
Assignee: DEFREES BARBARA BALDWIN WIDOW OF JOSEPH H DEFREES DEC'D
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Filing: 1967-02-06
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Granted: 1969-12-30
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Expires: 1987-02-06
Abstract
No abstract record available.
Inventors
- 👤 Joseph H De Frees
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 10:15
CPC Classifications
F; F16; F16K; F16K1/00; F16K1/30; F16K1/301; F16K1/307; F16K1/32; F16K1/34; F16K1/36; F16K24/00; F16K24/04; Y; Y10; Y10T; Y10T137/00; Y10T137/8593; Y10T137/86292; Y10T137/86324
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US3125320A
Cited
US2638924A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1972-12-29 | 1973-06-30 | 1973-12-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1976-12-29 | 1977-06-30 | 1977-12-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1980-12-29 | 1981-06-30 | 1981-12-30 | $7700.00 | Window Closed / Lapsed |