The two ends of the traction rope are respectively connected to the car and the counterweight, wrapped around the traction wheel and the guide wheel. The traction motor drives the traction wheel to rotate after changing speed through the reducer. With the traction force generated by the friction between the traction rope and the traction wheel, the lifting motion of the car and the counterweight is achieved, achieving the transportation purpose. 

An elevator is a vertical lift powered by an electric motor, equipped with a box shaped car, used for carrying people or goods in multi story buildings. There are also stair treads that run continuously on tracks, commonly known as escalators or moving walkways. Fixed lifting equipment serving designated floors. A vertical elevator has a car that runs between at least two vertical rigid guide rails. The size and structural form of the elevator car are convenient for passengers to enter and exit or for loading and unloading goods. Traditionally, regardless of its driving method, elevators are regarded as a general term for vertical transportation vehicles within buildings. According to speed, elevators can be classified into low-speed elevators (less than 1 meter/second), high-speed elevators (1-2 meters/second), and high-speed elevators (more than 2 meters/second). Hydraulic elevators began to appear in the mid-19th century and are still used in low rise buildings today. In 1852, in the United States, E G. Otis has developed a safety elevator that uses steel wire ropes for lifting. In the 1980s, the driving device was further improved, such as the electric motor driving the winding drum through worm gear transmission, and the use of balance weights. At the end of the 19th century, friction wheel transmission was adopted, greatly increasing the lifting height of elevators.