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US4905111A
Expired / Lapsed
US
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Damping material of an improved formulation for use on a magnetic head
Assignee: US Philips Corp
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Filing: 1988-07-26
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Granted: 1990-02-27
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Expires: 2008-07-26
Abstract
Abstract A damping material (19) is provided on one of the two side faces (7, 8), of a magnetic head having two plate shaped ferrite core limbs (3, 4). The material consists of a synthetic resin filled with less than 30% by volume of filler having a density of more than 10×10 3 kg/m 3 . The filler is at least 74% by weight of the damping material and the density of the damping material is larger than 4×10 3 kg/m 3 and its modulus of elasticity ranges between 10 7 and 10 9 Pa.
Inventors
- 👤 Wolfgang Tuma
- 👤 Ulrich Traxlmayr
- 👤 Walter Kodym
- 👤 Jean H. J. Lorteije
- 👤 Roeland Den Bakker
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 11:34
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/127; G11B5/187; G11B5/23; G11B5/235; G11B5/48; G11B5/52; G11B5/53; G11B5/133
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
135 words
A magnetic head comprising two combined plate-shaped ferrite core limbs constituting on a side a tape contact face for a record carrier in which a gap bounded by the two core limbs terminates, a damping material being at least partly provided on at least one of the two side faces constituted by said two core limbs and extending transversely to the tape contact face, characterized in that the damping material is a synthetic resin filled with less than 30% by volume of filler, which filler has a density of more than 10×10 3 kg/m 3 and is at least 74% by weight of the damping material and in that the density of the damping material is larger than 4×10 3 kg/m 3 and its modulus of elasticity ranges between 10 7 and 10 9 Pa.
Claim 2
Dependent Claim
135 words
A magnetic head comprising two combined plate-shaped ferrite core limbs constituting on a side a tape contact face for a record carrier in which a gap bounded by the two core limbs terminates, a damping material being at least partly provided on at least one of the two side faces constituted by said two core limbs and extending transversely to the tape contact face, characterized in that the damping material is a synthetic resin filled with less than 30% by volume of filler, which filler has a density of more than 10×10 3 kg/m 3 and is at least 74% by weight of the damping material and in that the density of the damping material is larger than 4×10 3 kg/m 3 and its modulus of elasticity ranges between 10 7 and 10 9 Pa.
Claim 3
Dependent Claim
16 words
A magnetic head as in claim 1 wherein the damping material comprises tungsten as a filler.
Claim 4
Dependent Claim
25 words
A magnetic head as in claim 1 wherein the density of the damping material is chosen to be of the order of 5.2×10 3 kg/m.
Claim 5
Dependent Claim
27 words
A magnetic head as in claim 1 wherein the modulus of elasticity of the damping material is chosen to be of the order of 3×10 8 Pa.
Claim 6
Dependent Claim
34 words
A magnetic head as in claim 1 wherein the damping material is provided on only a selected portion of the side faces with other portions of the side faces being free from damping material.
References Cited (Backward Citations)
US4528652A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-02-26 | 1993-08-28 | 1994-02-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-02-26 | 1997-08-28 | 1998-02-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-02-26 | 2001-08-28 | 2002-02-27 | $7700.00 | Window Closed / Lapsed |