An elevator is a permanent transport device that serves […]

An elevator is a permanent transport device that serves a number of specific floors within a building, the car of which operates in at least two columns of rigid orbital motion perpendicular to the horizontal plane or inclined at an angle of less than 15° to the plumb line. There is also a step type, and the tread plate is continuously operated on the crawler belt, commonly known as an escalator or a moving walkway. A fixed lifting device that serves the specified floor.

The vertical elevator has a car that runs between at least two columns of rigid rails that are perpendicular or have an angle of inclination of less than 15°. The car is sized and structured to allow passengers to access or load cargo. It is customary to use the elevator as a general term for vertical transportation vehicles in buildings, regardless of the driving method. According to the speed, it can be divided into low-speed elevator (4m/s or less), fast elevator 4~12m/s) and high-speed elevator (12m/s or more). Hydraulic elevators began to appear in the mid-19th century and are still used in low-rise buildings. In 1852, E.G. Otis of the United States developed a safety lift for wire rope lifting. In the 1980s, the drive unit was further improved, such as the motor driven by a worm drive to wind the reel, using a counterweight. At the end of the 19th century, friction wheel transmission was adopted, which greatly increased the lifting height of the elevator.