US3584378A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of making magnetic heads with means for preventing side erosion
Assignee: US Philips Corp
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Filing: 1969-09-07
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Granted: 1971-06-15
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Expires: 1989-09-07
Abstract
Abstract A METHOD OF MANUFACTURING A MAGNETIC HEAD WITH A HIGH RESISTANCE TO WEAR INCLUDES THE STEPS OF JOINING FIRST AND SECOND POLE PIECES WITH A NON-MAGNETIC MATERIAL HAVING A FIRST SOFTENING TEMPERATURE, AND THEN PLACING A SECOND NONMAGNETIC MATERIAL HAVING A SECOND SOFTENING TEMPERATURE LOWER THAN THE FIRST SOFTENING TEMPERATURE OF THE FIRST NONMAGNETIC MATERIAL AROUND THE POLE PIECES SURROUNDING THE RUNNING SURFACE OF THE MAGNETIC HEAD. THE NON-MAGNETIC MATERIAL HAS RESISTANCE TO WEAR CHARACTERISTICS APPROXIMATELY EQUAL TO THAT OF THE MATERIAL OF WHICH THE POLE PIECES ARE CONSTRUCTED. IN A FURTHER EMBODIMENT, THE STEPS ARE REVERSED AS ARE THE SOFTENING TEMPERATURES.
Inventors
- 👤 Simon Duinker
- 👤 Jules Bos
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 08:19
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/127; G11B5/187; G11B5/23; G11B5/235; G11B5/255; Y; Y10; Y10T; Y10T29/00; Y10T29/49; Y10T29/49002; Y10T29/4902; Y10T29/49021; Y10T29/49032; Y10T29/49036; Y10T29/49041; Y10T29/49055; Y10T29/49057
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
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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) | 1974-06-14 | 1974-12-14 | 1975-06-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-06-14 | 1978-12-14 | 1979-06-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-06-14 | 1982-12-14 | 1983-06-15 | $7700.00 | Window Closed / Lapsed |