An elevator is a platform or an enclosure raised and lowered in a vertical shaft to transport people and freight. The shaft contains the operating equipment, motor, cables, and accessories.
In 1846, Sir William Armstrong introduced the hydraulic crane, and in the early 1870s, hydraulic machines began to replace the steam-powered elevator. The hydraulic elevator is supported by a heavy piston, moving in a cylinder, and operated by the water (or oil) pressure produced by pumps.
Hydraulic lifts provide much security. In case of any fault in the driving group, or broken pipes, a valve at the entrance of the cylinder, regulates the output of oil to the cabin down gently.
Since the 19th century, cable elevators as well as water hydraulics were used for vertical transportation. In
1950’s, oil hydraulic elevator solutions were introduced in the U. S and in Germany at about the same time,
and quickly became popular. Initially, hydraulic elevators were used for vertical transport of general freight
(excluding passengers) and over time, due to improvements in valve controls and economic reasons,
hydraulic elevators started being used for transferring passengers. The economic reasons that favored
hydraulic versus traction included the cost of hoist-way construction, equipment and labor required for
installation.
