Elevator is a kind of vertical elevator powered by motor, equipped with box-shaped pod, which is used to transport people or goods in multi-storey buildings. There is also a step, the pedal is installed on the track and runs continuously, commonly known as escalator or moving sidewalk. Fixed lifting equipment serving designated floors. The vertical elevator has a car, and the car runs between at least two rows of rigid guide rails with vertical or inclined angles less than15. The size and structure of the carriage are convenient for passengers to enter, exit or load and unload goods. Traditionally, regardless of its driving mode, elevators are regarded as the general name of vertical vehicles in buildings. According to the speed, it can be divided into low-speed elevators (below 1m/s), fast elevators (1m/s) and high-speed elevators (above 2m/s). Hydraulic elevators began to appear in the middle of19th century and are still used in low-rise buildings. In 1852, Otis Company of the United States, for example, developed a safety elevator for wire rope hoisting. In the 1980s, the driving device was further improved, such as the motor driving the drum through worm drive, and the counterweight was adopted. At the end of 19, friction wheel transmission was adopted, which greatly increased the lifting height of the elevator.
At the end of 20th century, the elevator used permanent magnet synchronous traction machine as power. It greatly reduces the floor space of the computer room, and has the advantages of low energy consumption, energy saving and high efficiency, and fast lifting speed, which greatly promotes the development of real estate in the direction of super high-rise buildings.
ThyssenKrupp Elevator Company has developed a new type of "multi-elevator", which can run horizontally and vertically.