US3819427A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of making an electromagnetic-sheet stack
Assignee: Ludwig-Ofag-Indugas Ind GmbH
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Filing: 1972-06-21
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Granted: 1974-06-25
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Expires: 1992-06-21
Abstract
Abstract A plurality of identical ferromagnetic sheets are stamped or punched from a larger sheet of silicon-alloy steel. A finely divided powder of an inert bond inhibitor and spacer is mixed with the oil applied to the sheets during the stamping operation, or is applied to the sheets before or after stamping. The coated sheets are thereafter stacked and fastened together and heated to a temperature sufficient to anneal them and to form an insulating oxide layer on the sheets.
Inventors
- 👤 V Baesch
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 12:55
CPC Classifications
H; H02; H02K; H02K15/00; H02K15/02; H01; H01F; H01F1/00; H01F1/01; H01F1/03; H01F1/12; H01F1/14; H01F1/147; H01F1/14766; H01F1/14775; H01F1/14783; H01F27/00; H01F27/24; H01F27/245; H01F27/34; H01F27/341; H01F41/00; H01F41/02; H01F41/0206; H01F41/0233; H02K1/00; H02K1/04
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US2354123A
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US2484242A
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US3189483A
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US3076160A
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US3240638A
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US3562029A
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-06-24 | 1977-12-24 | 1978-06-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-06-24 | 1981-12-24 | 1982-06-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-06-24 | 1985-12-24 | 1986-06-25 | $7700.00 | Window Closed / Lapsed |