Skipper detection device for sewing machine seams

摘要

To provide a detection device for sewing machine seam skip which has a simple structure and which has high detection accuracy.SOLUTION: A detection device for sewing machine seam skip includes: a lower air nozzle 34 and an upper air nozzle 35 for imparting an external force to a bobbin thread for constituting seams of a paper bag; and a first thread detection sensor 36 and a second thread detection sensor 37 for detecting the bobbin thread in the case where the bobbin thread has moved by a predetermined distance by an external force. Thereby, fraying of the bobbin thread of seams where seam skips occurred in the sewing machine seams is detected by the first thread detection sensor 36 and the second thread detection sensor 37, and the occurrence of seam skips in the sewing machine seams is detected.SELECTED DRAWING: Figure 10