Apparatus for preventing stitching from raveling

摘要

The present invention relates to an apparatus for preventing a double chain stitching from raveling. Looper thread engaging structure engages with the looper thread consecutive to the looper from the cloth by moving when the looper is at the forward position and forms a looper thread loop consecutive from the cloth at the engaged portion by driving a sewing machine in the engaged state. A looper thread cutter cuts the looper thread loop at the engaged portion and a thread cutter cuts the loop-shaped needle thread consecutive to the needle via the looper from the cloth and the looper thread consecutive to the looper from the cloth between the cloth and the looper. Therefore, it is able to prevent a double chain stitching from raveling from the stitching end side. Further, defining structure is provided to define the moving distance of the looper thread engaging structure. The length of the looper thread loop is changed by definition of the moving distance of the looper thread engaging structure by the defining structure. Therefore, the thread of the thread end left over in the cloth by the looper thread cutter can be varied. By varying the length of the thread end consecutive to the sewn end side, a good-looking sewn product is obtained.