US3383115A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Gas seal for furnaces
Assignee: National Gypsum Co
•
Filing: 1965-04-27
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Granted: 1968-05-14
•
Expires: 1985-04-27
Abstract
No abstract record available.
Inventors
- 👤 Doris E Eckley
- 👤 William K Johnston
- 👤 John L Carlson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 22:04
CPC Classifications
F; F27; F27B; F27B7/00; F27B7/20; F27B7/22; F27B7/24; Y; Y10; Y10S; Y10S277/00; Y10S277/903
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) | 1971-05-14 | 1971-11-13 | 1972-05-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1975-05-14 | 1975-11-13 | 1976-05-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1979-05-14 | 1979-11-13 | 1980-05-14 | $7700.00 | Window Closed / Lapsed |