Patent ID: 8536861

Claim:
A wire rope flaw detector comprising: a magnetizer including a back yoke, and a pair of permanent magnets disposed on the back yoke such that polarities thereof are opposite to each other, and forming a main magnetic path in a predetermined segment in an axial direction of a wire rope; and a leakage magnetic flux detection section disposed in the predetermined segment in the axial direction, and detecting leakage magnetic flux generated from a damaged portion of the wire rope, wherein each of the permanent magnets (i) has a cross-section of a U-shape to embrace the wire rope when each permanent magnet is cut along a plane perpendicular to the axial direction of the wire rope, and (ii) has a magnetic orientation, on the cross-section of the permanent magnet, oriented toward the wire rope, a groove portion of each of the permanent magnets having the U-shaped cross section is magnetized to have a first magnetic pole, and an outer portion of each of the permanent magnets having the U-shaped cross-section is magnetized to have a second magnetic pole opposite the first magnetic pole.