Patent US2798502A successfully refreshed from Google Patents.
Patent US2561049A successfully refreshed from Google Patents.
US2561049A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Protection of low-frequency amplifier or output tubes against overload
Assignee: Hartford National Bank and Trust Co
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Filing: 1947-07-19
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Granted: 1951-07-17
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Expires: 1967-07-19
Abstract
No abstract record available.
Inventors
- 👤 Buys Pieter Klaas
- 👤 Cluwen Johannes Meyer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 20:43
CPC Classifications
H; H04; H04H; H04H20/00; H04H20/12; H03; H03F; H03F1/00; H03F1/52; H03F1/54; H03F1/548; H03F3/00; H03F3/20; H03F3/22; H03F3/26; H03F3/28; H04H20/02
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) | 1954-07-16 | 1955-01-15 | 1955-07-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1958-07-16 | 1959-01-15 | 1959-07-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1962-07-16 | 1963-01-15 | 1963-07-17 | $7700.00 | Window Closed / Lapsed |