The towline is generally applied to cables, oil pipes, gas pipes, water pipes and air ducts of machine tools and machinery to play the role of traction and protection. In use, the towline becomes the protective casing for these pipes, located outside the pipes. Nowadays, the towline is widely used in the machinery industry, and the tow chains sold in the market are various, each of which has different design concepts, and strives to meet the requirements of different machines. However, the towline is often of a fixed size, especially in the width direction, and the width of the towline is constant after fabrication. In modern practical machinery use, the width requirement of the drag chain is often variable. The singularity of the width of the drag chain brings inconvenience to industrial use.