US3500174A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Soft start and soft stop of an a.c. voltage
Assignee: KARL H ELLERBECK
•
Filing: 1968-02-21
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Granted: 1970-03-10
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Expires: 1988-02-21
Abstract
No abstract record available.
Inventors
- 👤 Karl H Ellerbeck
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 16:05
CPC Classifications
G; G05; G05F; G05F1/00; G05F1/10; G05F1/12; G05F1/40; G05F1/44; G05F1/445; H; H03; H03K; H03K17/00; H03K17/28; H03K17/292
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) | 1973-03-09 | 1973-09-08 | 1974-03-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1977-03-09 | 1977-09-08 | 1978-03-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1981-03-09 | 1981-09-08 | 1982-03-10 | $7700.00 | Window Closed / Lapsed |