History

Elevators, in concept, have been around since the BC era. The earliest reference to an elevator was found in a report from Vitruvius, a Roman architect; he wrote that Archimedes built his first elevator around 236 BC Between Italy, the United States, China, South Korea and Spain, over 7 million elevators have been built in those countries alone.

A more recognizable predecessor to our modern elevators was borne from the need to move raw materials, like coal and lumber, during the industrial era. Coal mine elevators used steam power to operate and move supplies and goods in bulk. Steam power was supplanted by hydraulic systems, first invented in 1846. From there, rope controlled elevators were developed, with a safety elevator coming shortly after that. This safety elevator prevented the fall of the elevator if the cable broke, and was designed by Elisha Otis. A modernized version of this is still in use today.

In general, there are four types of elevators: traction, hydraulic, climbing, and pneumatic. Traction elevators use electric motors and gears to move hoist ropes that move the passenger car. There are also traction elevators that do not use gears and rely solely on motors to move. Hydraulic elevators use either hydraulic cylinders or both cylinders and rope systems to ascend or descend. They are more common in low rise and fewer traffic applications. Climbing elevators use electric or combustion engines to move via propulsion. These are used in masts or towers to allow for easy access to different areas of the construction for maintenance. Pneumatic elevators utilize a vacuum and valve system to move the car. However, due to limitations, these elevators cannot hold much weight.