Patent US3448219A successfully refreshed from Google Patents.
US3448219A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Pressure balancing conservator for a transformer
Assignee: Individual
•
Filing: 1967-12-05
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Granted: 1969-06-03
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Expires: 1987-12-05
Abstract
No abstract record available.
Inventors
- 👤 Shinji Nakazawa
- 👤 Tohru Nakazawa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 04:45
CPC Classifications
H; H01; H01F; H01F27/00; H01F27/08; H01F27/10; H01F27/12; H01F27/14
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US3019280A
Cited
US1088197A
Cited
US2034736A
Cited
US1944005A
Cited
US2668186A
Cited
US3330902A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1972-06-02 | 1972-12-02 | 1973-06-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1976-06-02 | 1976-12-02 | 1977-06-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1980-06-02 | 1980-12-02 | 1981-06-03 | $7700.00 | Window Closed / Lapsed |