A sewing machine is a machine that uses one or more sewing threads to form one or more kinds of stitches on the sewing materials, so that one or more layers of sewing materials are interwoven or sewn together. The sewing machine can sew cotton, hemp, silk, wool, artificial fiber and other fabrics, leather, plastic, paper and other products. The stitches are neat, beautiful, flat and firm. The sewing speed is fast and the usage is simple.

General sewing machines are composed of four parts: head, base, transmission and accessories. The head is the main part of the tailoring machine. The base is divided into two forms: the table and the case. The transmission part is composed of frame, hand shaker or motor. Sewing machine accessories include needle, spindle, knife, oil pot, etc.

1. Development History

In 1790, St. Thomas of England invented the hand-held tailoring machine with single chain stitch for sewing boots and shoes. It is the first sewing machine in the world that uses wood as the body and some parts made of metal materials. In 1841, Timonier of France designed and manufactured a practical two-wire chain stitch sewing machine. In 1846, Howe of the United States obtained a patent for a curve lock stitch sewing machine, the efficiency of which was more than five hand-operated stitchers. In 1851, the American Machinist Shengjia independently designed and manufactured the Shengjia sewing machine, and in 1853 it obtained the United States patent. Since then, the sewing machine has been widely used in production, and gradually increased the functions of nailing buttons, locking button holes, reinforcement, embroidery, etc. In 1975, the United States invented a microcomputer controlled household multi-function sewing machine, which is more professional and faster.

2. Classification and Working Principle

There are many ways to classify stitching machines. The most common way is to distinguish sewing machines according to their stitches and uses. Sewing machine stitches can be classified into two types: lock stitch and chain stitch.

Lock stitch is the most common one. It is composed of two stitches, which are interwoven with each other like twine, and the interwoven point is in the middle of the sewing material. From the cross-section of the stitch, the two stitches are locked like two locks, so they are called lock stitch. This kind of stitch is applied in cotton, wool fabric or leather with small shrinkage. The shape of the front and the back is the same as a dotted line. The stitches are densely distributed and the sewing fastness is generally higher than that of manual sewing.

Chain stitch is formed by the self connection or interconnection of the suture rings. Those commonly used are single line chain, double line chain and three thread wrapped stitch. The characteristics of this kind of stitching are that the stitching is elastic and can stretch and contract with the sewing material without breaking the stitching. It is suitable for the clothing of elastic fabric or the products and garment blanks with seams easy to be loosen when sewing.

In the 1950s, household industrial sewing machines only had the function of adjusting the length of stitches and the front and back movement of fabrics. By the 1960s or so, the functions of hemming, embroidery and buttonhole locking were added. Then came the home sewing machines with pre-set fancy stitches, and later on the home sewing machines with micro-computer.