US3666568A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of improving punchability of steel sheets
Assignee: JFE Steel Corp
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Filing: 1970-06-16
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Granted: 1972-05-30
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Expires: 1990-06-16
Abstract
Abstract A METHOD OF IMPROVING THE PUNCHABILITY OF ELECTRICAL STEEL SHEETS AND THE LIKE, BY APPLYING A FIRST LAYER ON THE STEEL SHEETS, WHICH CONTAINS ONE OR MORE OF CHROMIC ACID, CHROMATES, AND BICHROMATES, AND A SECOND LAYER CONSISTING OF VARNISH ON THE FIRST LAYER.
Inventors
- 👤 Hiroshi Shimanaka
- 👤 Toshio Irie
- 👤 Toshikuni Tanda
- 👤 Tomoyuki Ichi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 05:22
CPC Classifications
B; B05; B05D; B05D7/00; B05D7/14; B05D2350/00; B05D2350/20
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-05-30 | 1975-11-29 | 1976-05-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-05-30 | 1979-11-29 | 1980-05-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-05-30 | 1983-11-29 | 1984-05-30 | $7700.00 | Window Closed / Lapsed |