What is a screw elevator?

Screw elevator refers to a structure that we can see every day instead of wire rope and pulley block → the screw and nut are connected with the car, and the screw is driven by the motor to rotate. At this time, the nut must be turned so that the car will move up and down. The advantage is that there will be no accident of free fall, and the disadvantage is that it is not suitable for very high floors.