Under-thread feed without gripper bobbin on two-thread lockstitch sewing machines

摘要

The invention solves an old problem: the omission of the gripper bobbins. The inclusion of a thread-guide channel in the gripper mounting and the gripper is possible in a technically simple way and affords hitherto undreamt-of advantages. Use of the two-thread lockstitch sewing machines is entirely without difficulty as a result of the under-thread guide according to claim 1. The thread change is as simple as for the upper thread as the result of the pull-through of the new thread after knotting with the old thread has taken place. As the result of the long and always visible under-thread, the use of the two-thread lockstitch sewing machine in automatically working sewing systems becomes possible for the first time and will replace the not always desirable double-in-and-out stitch sewing machine.