METHOD AND APPARATUS FOR DETECTING HOLES IN SHEET MATERIAL

摘要

P THE INVENTION RELATES TO A METHOD AND APPARATUS FOR DETECTING HOLES IN SHEET MATERIAL. /P P A RADIATION BEAM PRODUCED BY A LASER 11 BROOMS SHEET MATERIAL 10 USING A DRUM REFLECTIVE 14. THE DRUM FACETS ARE ARRANGED IN A WAY THAT SUCCESSIVE SCANS ARE INCLINED UPSTREAM AND DOWNSTREAM RELATIVE TO THE SHEET PERPENDICULAR. LIGHT PASSING THROUGH A HOLE OF THIS MATERIAL IS RECEIVED BY A LIGHT GUIDE 22 WHICH TRANSMITS IT TO A PHOTODETECTOR 36. /P P THE INVENTION APPLIES IN PARTICULAR TO THE DETECTION OF HOLES IN IRON SHEETS WHITE FOR CANNED TINS. /P