Eddy current and variable reluctance test apparatus for rollers and the like

摘要

Non-destructive testing apparatus for rollers and the like of magnetic material comprises a pair of rotating spin rails having intermediate sections of magnetic material. Feeding apparatus deposits rollers on the spin rails and moves them successively past the magnetic sections. A magnet produces flux through the magnetic sections and a roller rotating thereon. Variable reluctance sensing apparatus senses changes in the flux. An eddy current test probe is positioned adjacent the magnetic sections. Variable reluctance and eddy current test circuits produce flaw output signals which control apparatus for segregating the rollers. Advantageously the feeding apparatus intermittently deposits successive rollers on the spin rails and intermittently moves the rollers along the rails in end-to-end relationship. Flaw signals are stored and utilized for segregation after a predetermined number of intermittent movements of the rollers to an ejection station where they are raised and deflected from the spin rails into segregating chutes. Particular feeding apparatus using a channeled head movable over a slot are described. In a modification for testing tapered rollers, a cam follower and guide tapered roller maintain a constant spacing of the eddy current probe from the roller under test. Timing apparatus are described for making the eddy current test during forward movement of a roller past the probe, and the variable reluctance test during intervals between the forward movements.