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US2858457A
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Symmetrical component sensing system
Assignee: HARTMAN ELECTRICAL MANUFACTURING Co
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Filing: 1955-04-29
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Granted: 1958-10-28
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Expires: 1975-04-29
Abstract
No abstract record available.
Inventors
- 👤 Philip L Epstein
- 👤 Robert L Arntz
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 16:06
CPC Classifications
H; H02; H02H; H02H3/00; H02H3/26; H02H3/32; H02H3/34; H02H3/343
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) | 1961-10-27 | 1962-04-28 | 1962-10-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1965-10-27 | 1966-04-28 | 1966-10-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1969-10-27 | 1970-04-28 | 1970-10-28 | $7700.00 | Window Closed / Lapsed |