US4016487A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Arrangement of eddy current scanning coils
Assignee: Institut Dr Friedrich Foerster Pruefgeraetebau GmbH and Co KG
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Filing: 1976-03-08
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Granted: 1977-04-05
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Expires: 1996-03-08
Abstract
Abstract At least two groups of scanning coils are arranged with respect to the surface of metal parts to be tested at different angles. Means are further provided for oscillating at least one group of scanning coils in a direction generally perpendicular to the normal direction of travel of the scanning coil. Optionally, the exciter windings are rectangular, circular or oval.
Inventors
- 👤 Peter Neumaier
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 01:28
CPC Classifications
G; G01; G01N; G01N27/00; G01N27/72; G01N27/82; G01N27/90; G01N27/9013; G01N27/904
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
128 words
An arrangement of eddy current scanning coils for determining the presence of surface and near-surface defects in a metal part moving relatively thereto, each scanning coil including an exciter winding for producing eddy currents in the metal part and a receiver winding for receiving signals produced by defects, the exciter winding axis being substantially normal to the part surface being scanned and the receiver winding axis being perpendicular to the exciter winding axis, the improvement comprising: the scanning coils being arranged in at least two groups, with the scanning coils of the groups being oriented to be effective for different angular ranges of defects; and means provided for oscillating at least one scanning coil normally to the direction of relative movement between the scanning coils and metal part.
Claim 2
Dependent Claim
128 words
An arrangement of eddy current scanning coils for determining the presence of surface and near-surface defects in a metal part moving relatively thereto, each scanning coil including an exciter winding for producing eddy currents in the metal part and a receiver winding for receiving signals produced by defects, the exciter winding axis being substantially normal to the part surface being scanned and the receiver winding axis being perpendicular to the exciter winding axis, the improvement comprising: the scanning coils being arranged in at least two groups, with the scanning coils of the groups being oriented to be effective for different angular ranges of defects; and means provided for oscillating at least one scanning coil normally to the direction of relative movement between the scanning coils and metal part.
Claim 3
Dependent Claim
47 words
An arrangement of eddy current scanning coils as in claim 1, in which the receiver windings of one group have their axes aligned with the direction of relative movement, and the scanning coils of the other group are oscillated substantially perpendicularly to the direction of relative movement.
Claim 4
Dependent Claim
73 words
An arrangement as in claim 1, in which said groups of scanning coils are mounted on a common carrier, the receiver winding axes of one group of coils being aligned with the direction of relative movement, and the axes of the scanning coils of the other group being perpendicular to the direction of relative movement; and there are further provided means for oscillating the carrier substantially perpendicularly to the direction of relative motion.
Claim 5
Dependent Claim
41 words
An arrangement as in claim 1, in which the axes of the receiver windings of one group are disposed at +45° to the direction of relative movement and the axes of the receiver windings of the other group at -45° thereto.
Claim 6
Dependent Claim
23 words
An arrangement as in claim 1, in which the exciter winding of at least one group of scanning coils is of circular geometry.
Claim 7
Dependent Claim
24 words
An arrangement as in claim 1, in which the exciter windings of at least one group of scanning coils are generally oval in shape.
Claim 8
Dependent Claim
23 words
An arrangement as in claim 6, in which the length to width ratio of the oval exciter windings is substantially 1.4 to 1.
Claim 9
Dependent Claim
33 words
An arrangement as in claim 1, in which the exciter windings of at least one group of scanning coils are rectangular with the ratio of length to width being substantially 1.6 to 1.
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) | 1980-04-04 | 1980-10-04 | 1981-04-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-04-04 | 1984-10-04 | 1985-04-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-04-04 | 1988-10-04 | 1989-04-05 | $7700.00 | Window Closed / Lapsed |