Rotating head mechanism of rotary type ac magnetic flux leakage flaw

Abstract

A rotating head mechanism of a rotary type AC magnetic flux leakage flaw detector comprises a rotating disc which has an opening for passing a test piece for flaw detection, mounting frames which are disposed in the rotating disc so as to oppose to each other with the opening located therebetween, shafts which are rotatably disposed across the mounting frames and each of which has external threads of senses opposite to each other at a position on one side of the opening and a position on the other side thereof, a first nut which engages the external thread of one sense in the external threads of each shaft, a second nut which engages the external thread of the other sense in the external threads of each shaft, a first cradle which is coupled to the first nuts, a second cradle which is coupled to the second nuts, a first exciting magnetic poles/detecting probes-assembly which is mounted on the first cradle, a second exciting magnetic poles/detecting probes-assembly which is mounted on the second cradle, and rotation drive means for rotating the shafts. When the shafts are rotated by the rotation drive means, the first and second nuts are moved in a direction in which they come near to each other or away from each other along the shafts, thereby making it possible to change an opposing spacing in a diametrical direction of the opening, between the first and second exciting magnetic poles/detecting probes-assemblies respectively mounted on the first and second cradles.