GB1263968A - Method and apparatus for inspecting surfaces of articles - Google Patents

Abstract

1,263,968. Photo-electric flaw detection. NIPPON SEIKO K. K. May 15, 1969 [May 22, 1968], No.24903/69. Heading G1A. Objects are inspected photo-electrically for flaws. A roller bearing 4, for example, is continuously rotated by drive rollers 2, 3 while being illuminated by elongated lamp 5. An array of fibre optic bundles 1 have their first ends located to view respective sections along the length of the bearing surface and their other ends feed an array of phototransistors 1-10. These detectors are connected in pairs, preferably comprising spaced-apart detectors e. g. No. 1 with No. 10, No. 2 with No. 6 &c. as in Fig. 2 (not shown), in bridge circuits the out-of-balance signals from each of which is amplified by a D. C. differential amplifier (28), and fed to a Schmitt trigger circuit (32) via an adjustment circuit (30). Either the amplifier or the trigger itself can be adjusted to set the triggering level, out-of-balance signals which are above this level representing the presence of flaws. The Schmitt triggers feed a common OR-gate (34) operating an electromagnetic device (36) to effect sorting out of defective bearings when a succession of these are examined. Further pairs of photo-transistors supplied by optic fibre bundles monitor the ends of the bearings (Nos. 11, 12) and the overall gloss of the surface (Nos. 13 and 14). The apparatus may be modified to examine ring shaped objects or ball bearings or to monitor the blackening of or blowing of a lamp filament. The detectors may be alternatively photo-cell or photodiodes.