US5022275A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Strain measuring device employing magnetostriction and having a magnetic shielding layer
Assignee: Mitsubishi Electric Corp
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Filing: 1989-04-12
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Granted: 1991-06-11
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Expires: 2009-04-12
Abstract
Abstract In a strain measuring device employing a magnetic permeability detector means to detect an amount of strain in a passive member as changes of magnetic permeability in a magnetostrictive layer, a magnetic shielding layer is formed on the surface of the passive member, and the magnetostrictive layer is formed thereon so as to lessen the adverse effects of the passive member caused by the magnetic characteristics of the passive member in strain measurement, that is, to reduce measurement errors. Alternatively, a magnetostrictive layer is formed on the surface of the passive member, or a magnetic shielding layer is partially forrmed on the surface of the passive member of soft magnetic material with high permeability, so as to lessen the influence of the passive member caused by thermal stresses of the passive member in strain measurement, that is, to reduce measurement errors. Further, there is provided a strain measuring device which facilitates formation of the magnetostrictive layer.
Inventors
- 👤 Hiroshi Satoh
- 👤 Yoshihiko Utsui
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 06:09
CPC Classifications
G; G01; G01L; G01L1/00; G01L3/00; G01L3/02; G01L3/04; G01L3/10; G01L3/101; G01L3/102; G01L3/103; G01L1/12; G01L1/125; G01R; G01R1/00; G01R1/02; G01R1/10; G01R1/12; Y; Y10; Y10S; Y10S505/00; Y10S505/70; Y10S505/701; Y10S505/825; Y10S505/842; Y10S505/872
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
140 words
A strain measuring device comprising: a passive member of soft magnetic and magnetostrictive material with high permeability which varies as a function of an external force; a magnetic shielding layer covering selected portions of the surface of said passive member for shielding said selected covered portions of the surface of said passive member from external magnetic influence, such that those portions of said passive member which are not covered by said magnetic shielding layer remain exposed to external magnetic influence; and a permeability detection means positioned around said passive member for subjecting those portions of said passive member not covered by said magnetic shielding layer to magnetic flux and for detecting changes of magnetic permeability in those portions of the surface of said passive member not covered by said magnetic shielding layer, caused by strain produced by the external force.
Claim 2
Dependent Claim
140 words
A strain measuring device comprising: a passive member of soft magnetic and magnetostrictive material with high permeability which varies as a function of an external force; a magnetic shielding layer covering selected portions of the surface of said passive member for shielding said selected covered portions of the surface of said passive member from external magnetic influence, such that those portions of said passive member which are not covered by said magnetic shielding layer remain exposed to external magnetic influence; and a permeability detection means positioned around said passive member for subjecting those portions of said passive member not covered by said magnetic shielding layer to magnetic flux and for detecting changes of magnetic permeability in those portions of the surface of said passive member not covered by said magnetic shielding layer, caused by strain produced by the external force.
Claim 3
Dependent Claim
24 words
A strain measuring device as defined in claim 1, wherein said passive member is of ferromagnetic material of cylindrical shape with circular cross section.
Claim 4
Dependent Claim
23 words
A strain measuring device as defined in claim 2, wherein said permeability detection means is a coil for generating magnetic fluxes on energization.
Claim 5
Dependent Claim
18 words
A strain measuring device as defined in claim 3, wherein said magnetic shielding layer is of superconductive material.
Claim 6
Dependent Claim
17 words
A strain measuring device as defined in claim 4, wherein said superconductive material is of high-temperature superconductivity.
Claim 7
Dependent Claim
19 words
A strain measuring device as defined in claim 2, wherein said magnetic shielding layer is of paramagnetic high-conductive material.
Claim 8
Dependent Claim
20 words
A strain measuring device as defined in claim 2, wherein said magnetic shielding layer is of diamagnetic high conductive material.
Claim 9
Dependent Claim
33 words
A strain measuring device as defined in any one of claims 5 to 7, wherein said high-temperature superconductive material or high conductive material fixed to said passive member is of rectangular strip shape.
Claim 10
Dependent Claim
43 words
A strain measuring device as defined in any one of claims 5 to 7, wherein said high temperature superconductive material or high conductive material is fixed to said passive member at an angle of 45° to the axis thereof in rectangular strip shape.
Claim 11
Dependent Claim
24 words
A strain measuring device as defined in claim 1, wherein said magnetic shielding layer is fixed to said passive member through an adhesive layer.
Claim 12
Dependent Claim
28 words
A strain measuring device as defined in claim 1, wherein said magnetic shielding layer is directly formed on said passive member by plating, vapor deposition, ion-plating or sputtering.
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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) | 1994-06-10 | 1994-12-10 | 1995-06-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-06-10 | 1998-12-10 | 1999-06-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-06-10 | 2002-12-10 | 2003-06-11 | $7700.00 | Window Closed / Lapsed |