US4669015A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Multiple gap magnetic reading head
Assignee: US Philips Corp
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Filing: 1985-04-03
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Granted: 1987-05-26
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Expires: 2005-04-03
Abstract
Abstract A magnetic transducing head (1), for scanning a magnetic recording medium (14) which comprises a magnetizable surface (16) for retaining information in the form of a previously determined information pattern which is characterized by a restricted wavelength band, has a transducing gap (10) which is filled by a spacer consisting of a number (≧4) of layers (11) of a material of low magnetic permeability extending parallel to the core faces (6, 7) and forming sub-gaps, a layer (12) of higher permeability being interposed between every two successive layers (11) of low permeability. As a result of this the head (1) has a very high efficiency, while by adjusting in particular the spacings between the sub-gaps the head (1) can be given a desired band filter action.
Inventors
- 👤 Jacobus J. M. Ruigrok
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 07:43
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/127; G11B5/33; G11B5/39; G11B5/3903; G11B5/3906; G11B5/3916; G11B5/3919; G11B5/3922; G11B5/3925; G11B5/02; G11B5/09; G11B5/1278; G11B5/265; G11B5/2652; G11B5/31
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
151 words
A magnetic transducing head, for scanning a magnetic recording medium which has a magnetizable surface for retaining information in the form of a magnetization pattern characterized by a restricted wavelength band, comprising: a pair of core parts of a magnetizable material having a comparatively high magnetic permeability, which core parts have respective oppositely located core faces which define a transducing gap therebetween; electromagnetic means coupled to at least one of the core parts to produce an electric signal when a varying magnetic flux flows through the core parts; a spacer filling the transducing gap, the spacer comprising at least four layers of a material of a low magnetic permeability, which layers extend parallel to the core faces and form sub-gas, a layer of higher permeability being interposed between every two successive layers of low permeability, each layer of higher permeability defining the spacing between sub-gaps, said spacings being of unequal length.
Claim 2
Dependent Claim
151 words
A magnetic transducing head, for scanning a magnetic recording medium which has a magnetizable surface for retaining information in the form of a magnetization pattern characterized by a restricted wavelength band, comprising: a pair of core parts of a magnetizable material having a comparatively high magnetic permeability, which core parts have respective oppositely located core faces which define a transducing gap therebetween; electromagnetic means coupled to at least one of the core parts to produce an electric signal when a varying magnetic flux flows through the core parts; a spacer filling the transducing gap, the spacer comprising at least four layers of a material of a low magnetic permeability, which layers extend parallel to the core faces and form sub-gas, a layer of higher permeability being interposed between every two successive layers of low permeability, each layer of higher permeability defining the spacing between sub-gaps, said spacings being of unequal length.
Claim 3
Dependent Claim
19 words
A magnetic transducing head as claimed in claim 1, characterized in that the lengths of the sub-gaps are equal.
Claim 4
Dependent Claim
19 words
A magnetic transducing head as claimed in claim 1, characterized in that the lengths of the sub-gaps are unequal.
Claim 5
Dependent Claim
36 words
A magnetic head as claimed in claim 1, characterized in that the sub-gaps include at least two groups of sub-gaps, the sub-gaps of each group having equal spacings, the sub-gap spacings of different groups being different.
Claim 6
Dependent Claim
148 words
A magnetic transducing head, for scanning a magnetic recording medium which has a magnetizable surface for retaining information in the form of a magnetization pattern characterized by a restricted wavelength band, comprising a pair of core parts of a magnetizable material having a comparatively high magnetic permeability, which core parts have respective oppositely located core faces which define a transducing gap therebetween; electromagnetic means coupled to at least one of the core parts to produce an electric signal when a varying magnetic flux flows through the core parts; a spacer filling the transducing gap, the spacer comprising at least four layers of a material of a low magnetic permeability, which layers extend parallel to the core faces and form sub-gaps of unequal length, a layer of higher permeability being interposed between every two successive layers of low permeability, each layer of higher permeability defining the spacing between sub-gaps.
Claim 7
Dependent Claim
148 words
A magnetic transducing head, for scanning a magnetic recording medium which has a magnetizable surface for retaining information in the form of a magnetization pattern characterized by a restricted wavelength band, comprising a pair of core parts of a magnetizable material having a comparatively high magnetic permeability, which core parts have respective oppositely located core faces which define a transducing gap therebetween; electromagnetic means coupled to at least one of the core parts to produce an electric signal when a varying magnetic flux flows through the core parts; a spacer filling the transducing gap, the spacer comprising at least four layers of a material of a low magnetic permeability, which layers extend parallel to the core faces and form sub-gaps of unequal length, a layer of higher permeability being interposed between every two successive layers of low permeability, each layer of higher permeability defining the spacing between sub-gaps.
Claim 8
Dependent Claim
41 words
A magnetic transducing head as in claim 5 wherein there are n layers of said material of low magnetic permeability; n is an odd number, thereby defining a central sub-gap; said central sub-gap being longer than sub gaps to either side.
Claim 9
Dependent Claim
36 words
A magnetic head as claimed in claim 5, characterized in that the sub-gaps include at least two groups of sub-gaps, the sub-gaps of each group having equal spacings, the sub-gap spacings of different groups being different.
Claim 10
Dependent Claim
17 words
A magnetic transducing head as in claim 5 wherein the spacing between successive sub-gaps is substantially equal.
Claim 11
Dependent Claim
47 words
A magnetic transducing head as claimed in claim 8, characterized in that it holds that ##EQU5## wherein Σ g is the sum of the lengths of the sub-gaps, and ##EQU6## wherein a is the spacing between the sub-gaps, a=constant; and g max is the largest sub-gap length.
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) | 1990-05-25 | 1990-11-24 | 1991-05-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-05-25 | 1994-11-24 | 1995-05-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-05-25 | 1998-11-24 | 1999-05-26 | $7700.00 | Window Closed / Lapsed |