The belt has good elasticity, which can not only relieve shock and vibration during work, but also move smoothly and without noise. When the load is too large, the rear belt will slip on the wheels, so it can prevent damage to other parts and play a role of safety protection. As an intermediate part, the length of the belt can be selected according to the needs within a certain range to adapt to the working conditions with a large center distance. The structure is simple and easy to manufacture, installation and maintenance are very convenient, and the cost is relatively low.