TW200940773A - Seam ravel preventing method and apparatus therefor - Google Patents

Abstract

To provide a seam ravel preventing method capable of preventing seam ravel from the end side of sewing end of seam while gathering and disposing components inside a sewing machine bed, and an apparatus therefor.In a sewing machine provided with a vertically moving needle and a looper swinging forward and backward while clamping the needle, the apparatus is provided with a receiving knife disposed on the retreat position side of the looper, a hook moving back and forth from the receiving knife and a route change means for changing the back and forth movement route of the hook. At the end of sewing, in the state that the looper is moved forward, the hook is moved forth and engaged with a looper thread from a loop-like needle thread to the looper, the engaging part of the looper thread is cut with the receiving knife by the back movement following it, the back and forth movement route of the hook is changed after the back and forth movement of the hook, the sewing machine is driven for one stitch, and the looper is moved forward again. The hook is moved forth to be advanced to and engaged with the loop-like needle thread captured by the looper and is engaged with the looper thread from the loop-like needle thread to the looper, and the engaging part of each thread is cut with the receiving knife by the back movement following it.