Detector for faulty stitches using thread tension - compares actual tension with threshold tension derived from nominal value

摘要

A method of detecting and determining the location of stitching errors during the sewing of seams, esp. during the attachment of continuous rows of sliding clasp fastener latches to a carrier tape, measures the tension on the thread. A threshold value for the thread tension is registered and a positive deviation of the tension from this threshold value is identified as a faulty stitch. An average value for the thread tension is determined and this is multiplied by a weighted nominal value, to give the threshold value. System detects errors during the stitching operation, and does not depend upon visual observation.