Device for locating the edges of moving webs

摘要

PCT No. PCT/EP88/00882 Sec. 371 Date Jun. 16, 1989 Sec. 102(e) Date Jun. 16, 1989 PCT Filed Oct. 5, 1988 PCT Pub. No. WO89/03357 PCT Pub. Date Apr. 20, 1989.A device for continuously determining the position of the edge of a moving web uses a light signal from a light relay emitted in the direction of the edge of a web. The light signal is received and converted by the light relay into an input/output signal which is used as an indicator and as a control value for the position of the edge of the web. The signal outlet is moved together with the signal input preferably along a circular path which intersects the edge of the web twice so that the position of the edge of the web can be determined from the corresponding input/output signals obtained during each revolution.