Today, we share a super simple knowledge point. In the shoe machine, we often encounter the internal thread machine. So what is the internal thread machine and what is its function?

The name of the sewing machine includes: single line internal thread machine, double line internal thread machine, interior thread machine, sole sewing machine, vertical internal thread machine, horizontal internal thread machine, etc.

The process features of the sewing machine: sewing the inner thread is the process of stitching the upper foot, inner bottom and outer bottom together from the inner cavity of the shoe. The stitching of this kind of sewing process is on the upper foot inside the upper cavity on one side and on the bottom or side of the inner or outer sole on the other.

The stitching on the bottom is straight seam technology, while the stitching on the side is side seam technology. The straight seam technology is mostly used for through seam shoes or reinforced adhesive shoes; the side seam technology is mostly used for leather shoes or sports shoes with enclosure outsole.

The stitch with chain stitch is single thread sewing process, which is mostly used for stitching the upper foot and the inner bottom; the stitch with lock stitch is double thread sewing process, which is mostly used for stitching the upper foot and the outer bottom.

The top end of the bottom thread crank brace, commonly known as "ox horn", is inserted into the upper foot position inside the shoe cavity. With the rotation of the crank brace and the movement of the shoe on it, it forms sewing actions such as winding, feeding, pressing, hooking and tightening together with the sewing mechanism on the shoe machine head, so as to sew the upper foot and the outsole together.