The nut is usually rotatably driven to achieve vertical movement. The details of different transportations systems are explained further.
Elevators are mostly used to transport people, called passenger elevators. They can also be used to transport materials in which case they are called freight elevators. Whether the elevator is for people or for material, there are basically two types of systems.
One is overhead suspended elevator and another is hydraulic elevator. Suspended elevator uses steel cables and electric motors. These usually travel fast and are therefore used for tall buildings. Hydraulic elevator is operated by a hydraulic piston which is situated in a chamber below the elevator cab. The piston moves in a rotatory motion about its pivot which in turn makes the cab traverse vertically.
Elevator cabs move along vertical guide rails. For suspended elevators, an electric motor runs which lowers and raises the cab with the help of wired ropes. These ropes are designed to suit the capacity of the cab. It also has a flexible electric cable connected to it in order to provide lightning and also to facilitate button and door signals to be transmitted.
The construction of both kinds of elevators requires considerable effort below the point of lowest entry to cab. If the elevator serves the lowest building level, then it requires considerable depth of excavation and construction below the basement of the building. ...