Just like your car, most of the basic principles of sewing machines is the same. Car is the core of the internal-combustion engine, suture system sewing machine is the core of the coil. Suture with ordinary hand-sewing of the coil varies greatly. In the most simple of hand-sewn, sewing needle on the small eye at the end of a line, and then the PIN completely through the two pieces of fabric the joint line from the side through to the other side, then put back to the first side. In this way, needle drive lines into and out of fabric and stitching them together. Although the manual is very simple, but extremely difficult stretching by machine. Release pin machine needs to one side of the fabric, and then immediately grab it again on the other side. It then needs lines all pull out loose fabric, switch needle direction and repeat all the steps in the opposite direction. This process is too complicated for a simple machine, and impractical, and even for the manual, only with shorter lines are easy to use.