An elevator is a transportation device used to move goods or people vertically.
Elevators began as simple rope or chain hoists. An elevator consists of a cab or platform, the ropes required to raise and lower it and machinery to move the rope. Later refinements included steam power and hydraulic power.
In general, there are two types of elevators:
- Cable Elevators - Operate using a counterweight that allows the elevator to easily be pulled up or down using cables attached to the roof of the elevator car.
- Hydraulic Elevators - These are quite common. They use a hydraulically powered plunger to push the elevator upwards.
A different kind of elevator is used to transport material. It generally consists of an inclined plane on which a conveyor belt runs. The conveyor often includes partitions to prevent the material from sliding backwards. These elevators are often used in industrial and agricultural applications.
Elevators are also control surfaces on the wings of aircraft which control vertical ascent by changing the lift profile of the wing. The Wright Brothers' early aircraft worked by actually changing the shape of the entire wing. Today only a relatively small portion of the trailing edge of the wing is moved.