A pile-detecting apparatus is used in a machine wherein a pile fabric is deflected over a smooth surface of a roll to detect the edge between the pile-free portion of the fabric and the portion with the pile, which edge runs parallel to the displacement direction of the fabric over the roll. The apparatus has a support plate, a frame carrying the plate, a plurality of rollers mounted on the frame and riding on the surface of the deflecting roll, and at least one light source on the plate for generating light beams and directing same tangentially of the surface. Respective detectors on the plate receive the respective light beams.
展开▼
