The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Mar. 26, 1996
Filed:
Jul. 15, 1994
Seigo Ando, Tokyo, JP;
Yasuhiro Matsufuji, Tokyo, JP;
NKK Corporation, Kawasaki, JP;
Abstract
A magnetic inspection apparatus includes a magnetizer which generates a magnetic field in an object to be inspected, the object running in a predetermined direction, the magnetizer including a pair of magnetic poles provided in facing relation to the object, the pair of magnetic poles being arranged in the predetermined direction; a plurality of magnetic sensors arranged at small intervals in a widthwise direction of the object perpendicular to the predetermined direction, for detecting a leakage magnetic flux due to a defect of the object at locations in the widthwise direction, each magnetic sensor having sides which face the magnetic poles; a plurality of subtraction circuits, each calculating a difference signal between output signals from those ones of the magnetic sensors which are separated by a predetermined distance; a plurality of absolute value circuits, each calculating an absolute value of each difference signal output from each subtraction circuit; and an arithmetic operation circuit which evaluates the defect of the object on the basis of the absolute value signal output from each absolute value circuit, with the relationship between a distance E (unit=mm) between the magnetic sensors associated with the output signals subjected to subtraction in each subtraction circuit and a distance L (unit=mm) between each magnetic sensor and the object being defined by 17<EL<78.