NEEDLE PLATE ENABLING SEWING OF DECORATIVE PATTERN SIMILAR TO COVER STITCH, AND LOCK STITCH SEWING MACHINE MOUNTED WITH THE NEEDLE PLATE

摘要

PROBLEM TO BE SOLVED: To provide a lock stitch sewing machine with a needle hole for zigzag stitches, capable of sewing decorative patterns with simulated cover stitches formed of three threads consisting of two needle threads and one bobbin thread using straight stitches with twin needles, and capable of securely forming a firm seam with three treads.;SOLUTION: In a lock stitch sewing machine where the vertical motion of needles and a shuttle cooperate to form a seam, a long needle hole for zigzag stitches is provided through a needle plate of the lock stitch sewing machine. A nail-like member or a needle plate auxiliary plate is so provided as to cover the center part of the needle hole and to have a nail part tip projected in the cloth feed direction beyond a needle location toward the rear side of the sewing machine. A gap is provided at the tip side of the nail-like member for allowing a bobbin thread, which crosses the back surface of the nail-like member, to pass therethrough to the upper surface side of the needle plate. Alternatively, a gap is provided for allowing a bobbin thread, which crosses the back surface of the needle plate auxiliary plate, to pass therethrough to the upper surface side of the needle plate.;COPYRIGHT: (C)2013,JPO&INPIT