Patent US3777255A successfully refreshed from Google Patents.
US3777255A
Expired / Lapsed
US
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Position sensor utilizing a primary and secondary shielded from one another by a ferromagnetic shield and a magnet whose position relative to the shield changes the shielding
Assignee: Westinghouse Electric Corp
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Filing: 1972-10-26
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Granted: 1973-12-04
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Expires: 1992-10-26
Abstract
Abstract A position sensitive system including an exciting winding, a sensing winding, a ferromagnetic shield therebetween, and a magnet, the shield and the magnet being relatively movable. The magnetic skin depth is a function of the distance between the shield and the magnet, whereby voltage induced in the sensing coil by the exciting coil is a function of that distance. For any given set of parameters there will be a range wherein the depth of the magnetic skin of the shield is increased as the distance between the shield and the magnet is reduced, whereby voltage induced in the sensing coil increases as said distance decreases, and vice versa. This provides transducer capability which may be applied to proximity detection, mechanical excursion detection, and other uses. Examples of specific adaptations are as a position detector and, when coupled to either an elastic diaphragm or piston, as a pressure transducer.
Inventors
- 👤 F Young
- 👤 R Elco
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 13:36
CPC Classifications
G; G01; G01D; G01D5/00; G01D5/12; G01D5/14; G01D5/20; G01D5/204; G01D5/2006; G01D5/2033; G01L; G01L9/00; G01L9/0041; G01L9/007
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
123 words
A position sensitive system comprising first and second devices which are relatively movable with respect to each other, the first device comprising magnet means, the second device comprising first and second windings and a ferromagnetic shield interposed between said windings for controlling inductive coupling between said windings in accordance with the electromagnetic skin depth of the shield, means for supplying cyclic current to said first winding, the incremental permeability of said shield and thereby the electro-magnetic skin depth being a function of the positional relation between said magnet means and said shield, whereby the voltage induced in the second winding by the first winding is a function of said positional relation, and utilization means responsive to the voltage induced in the second winding.
Claim 2
Dependent Claim
123 words
A position sensitive system comprising first and second devices which are relatively movable with respect to each other, the first device comprising magnet means, the second device comprising first and second windings and a ferromagnetic shield interposed between said windings for controlling inductive coupling between said windings in accordance with the electromagnetic skin depth of the shield, means for supplying cyclic current to said first winding, the incremental permeability of said shield and thereby the electro-magnetic skin depth being a function of the positional relation between said magnet means and said shield, whereby the voltage induced in the second winding by the first winding is a function of said positional relation, and utilization means responsive to the voltage induced in the second winding.
Claim 3
Dependent Claim
45 words
The combination as in claim 1 wherein said magnet means has a magnetic force such that, within predetermined distance limits, the incremental permeability of said shield is lowered and the skin depth increased as the distance between the magnet means and the shield is reduced.
Claim 4
Dependent Claim
21 words
The combination as in claim 1 wherein said utilization means is a voltmeter calibrated in terms descriptive of said relative movement.
Claim 5
Dependent Claim
39 words
The combination as in claim 1 wherein said magnet means is movable and an object whose position is to be detected is connected to the magnet means to displace the magnet means in response to Displacement of the object.
Claim 6
Dependent Claim
36 words
The combination as in claim 1 wherein said shield is movable, and an object whose position is to be detected is connected to the shield to displace the shield in response to displacement of the object.
Claim 7
Dependent Claim
15 words
The combination as in claim 1 wherein said shield substantially envelopes one of said windings.
Claim 8
Dependent Claim
38 words
The combination as in claim 1 wherein said shield comprises a substantially closed hollow cylinder, one of said windings is within the cylinder, the other winding is outside the cylinder, and the magnet means is outside the cylinder.
Claim 9
Dependent Claim
18 words
The combination as in claim 7 wherein the windings and the peripheral wall of the cylinder are coaxial.
Claim 10
Dependent Claim
18 words
The combination as in claim 7 wherein the windings and the peripheral wall of the cylinder are concentric.
Claim 11
Dependent Claim
111 words
A position sensitive system comprising: A. first and second windings arranged for inductive coupling therebetween; B. means for supplying cyclic current to the first winding; C. a ferromagnetic shield interposed between said windings for controlling the amount of inductive coupling between the windings in dependence upon the magnetic skin depth of the shield; D. magnet means for affecting the permeability and thereby the skin depth of the shield in accordance with the relative positions of the shield and the magnet means, said shield and magnet means being relatively movable with respect to each other; and E. utilization means responsive to the voltage induced in the second winding by the first winding.
Claim 12
Dependent Claim
111 words
A position sensitive system comprising: A. first and second windings arranged for inductive coupling therebetween; B. means for supplying cyclic current to the first winding; C. a ferromagnetic shield interposed between said windings for controlling the amount of inductive coupling between the windings in dependence upon the magnetic skin depth of the shield; D. magnet means for affecting the permeability and thereby the skin depth of the shield in accordance with the relative positions of the shield and the magnet means, said shield and magnet means being relatively movable with respect to each other; and E. utilization means responsive to the voltage induced in the second winding by the first winding.
Claim 13
Dependent Claim
32 words
The combination as in claim 10 wherein one of said shield and said magnetic means is movable, and an object whose position is to be monitored is connected to said movable one.
References Cited (Backward Citations)
US3020527A
Cited
US3314002A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-12-03 | 1977-06-04 | 1977-12-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-12-03 | 1981-06-04 | 1981-12-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-12-03 | 1985-06-04 | 1985-12-04 | $7700.00 | Window Closed / Lapsed |