US3670239A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and apparatus for magnetic flaw detection by using magneto-sensitive diodes
Assignee: Nippon Steel Corp
•
Filing: 1970-03-19
•
Granted: 1972-06-13
•
Expires: 1990-03-19
Abstract
Abstract This invention relates to method and apparatus for inspecting flaws, herein magneto-sensitive diodes are used so as to provide a remarkably higher detecting sensitivity than of the conventional detector such as a search coil or Hall generator.
Inventors
- 👤 Toshio Shiraiwa
- 👤 Tatsuo Hiroshima
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 15:23
CPC Classifications
H; H10; H10D; H10D48/00; H10D48/40; G; G01; G01N; G01N27/00; G01N27/72; G01N27/82
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
141 words
Magnetic detection apparatus for detecting flaws in material spirally rotated along its longitudinal axis to expose the entire surface Thereof to the detection apparatus and having means for magnetizing said material comprising: a plurality of pairs of at least two detector elements for detecting the leakage flux emanating from a flaw in said material, said detector elements are symmetrically mounted one on each side of a null plane formed by said means for magnetizing; means for amplifying the respective outputs of said plurality of pairs of detector elements, means for demodulating the output of said means for amplifying, means responsive to said demodulated outputs for balancing the respective signals from each of said pair of detector elements, means for sensing the largest amplitude signal from said means for amplifying, and means responsive to said means for sensing to generate control signals.
Claim 2
Dependent Claim
141 words
Magnetic detection apparatus for detecting flaws in material spirally rotated along its longitudinal axis to expose the entire surface Thereof to the detection apparatus and having means for magnetizing said material comprising: a plurality of pairs of at least two detector elements for detecting the leakage flux emanating from a flaw in said material, said detector elements are symmetrically mounted one on each side of a null plane formed by said means for magnetizing; means for amplifying the respective outputs of said plurality of pairs of detector elements, means for demodulating the output of said means for amplifying, means responsive to said demodulated outputs for balancing the respective signals from each of said pair of detector elements, means for sensing the largest amplitude signal from said means for amplifying, and means responsive to said means for sensing to generate control signals.
Claim 3
Dependent Claim
75 words
Magnetic detection apparatus as in claim 1 wherein said means for sensing comprise a plurality of diodes each responsive to an output from said means for amplifying associated with a respective one of said pair of said detector elements, the outputs of said diode elements are summed at a given point so that only the signal output having the greatest amplitude is recognized, and means interconnecting said point to said means for generating control signals.
Claim 4
Dependent Claim
41 words
Magnetic detection apparatus as in claim 1 wherein pairs of said detector elements are formed into respective groups of detecting elements, means for demodulating the output signals from each group of detector elements to provide signals to said means for sensing.
Claim 5
Dependent Claim
15 words
Apparatus as in claim 1 wherein each of said detecting elements comprises a magneto-sensitive diode.
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) | 1975-06-13 | 1975-12-13 | 1976-06-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-06-13 | 1979-12-13 | 1980-06-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-06-13 | 1983-12-13 | 1984-06-13 | $7700.00 | Window Closed / Lapsed |