Apparatus for cutting out an edge portion of a coating sheet

Claim 1

In an apparatus for cutting out an edge portion of a coating sheet wherein a plurality of cords arranged at substantially equal intervals and in parallel with each other and conveyed along a predetermined path are integrally coated with rubber or the like to form cord portions in such a manner that the cord portions are expanded, to a predetermined length from a most externally positioned cord portion of the coating sheet in transversal direction thereof, comprising; a cutter for cutting out an edge portion of the conveying coating sheet, projecting means having a light source and a light guide which projects light emanated from the light source onto a region including at least the most externally positioned cord portion of the coating sheet, said projection means further comprising; a photoelectric conversion means for converting the amount of intensity distribution of light emanated from an image guide into electrical output signals, and signal treating means for detecting positions of a plurality of the cord portions and for detecting the position of the most externally positioned cord portion based on the detected positions of the cord portions; wherein the signal treating means shapes the output signals of the photoelectric conversion means by comparing them with a reference level to generate a plurality of pulses, treats these pulses to obtain widths X n of respective pulses and pulse intervals X' n of successive pulses, and treats a plurality of pulse widths X n and pulse intervals X' n to obtain mean value X n and X' n , except the maximum value and the minimum value thereof and obtain differences between these mean values X n and X' n and successive pulse widths X n and pulse intervals X' n , respectively, in the direction from the edge portion to the cord portion, in order, whereby when these differences satisfy a predetermined condition, if the relations |X n+1 -X n | and |X n+1 -X' n | have the following conditions, |X n+1 -X n |≦α, and |X' n+1 -X' n |≦β, wherein α and β are predetermined tolerances, the most externally positioned cord portion is detected; detection means having the image guide which receives light projected by the projection means and reflected from the coating sheet and for detecting the position of the most externally positioned cord portion based on the intensity distribution of the light emanated from the image guide, a head for integrally holding the cutter, an exit edge portion of the light guide and an entrance edge portion of the image guide, head translating means for moving the head in the transversal direction of the coating sheet, and means for controlling means in such a manner that the cutter is always positioned at the predetermined position to the most externally positioned cord portion of the coating sheet.