Primitive elevators were in use as early as the 3rd century BC, operated by human, animal, or water wheel power. From about the middle of the 19th century, power elevators, often steam-operated, were used for conveying materials in factories, mines, and warehouses.

In 1853, American inventor Elisha Otis demonstrated a freight elevator equipped with a safety device to prevent falling in case a supporting cable should break. This increased public confidence in such devices. Otis established a company for manufacturing elevators and patented (1861) a steam elevator. 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.

Electric elevators came into to use toward the end of the 19th century. The first one was built by the German inventor Werner von Siemens in 1880.

How Elevators Work
In a typical elevator, the car is raised and lowered by six to eight motor-driven wire ropes that are attached to the top of the car at one end, travel around a pair of sheaves, and are again attached to a counterweight at the other end.

The counterweight adds accelerating force when the elevator car is ascending and provides a retarding effort when the car is descending so that less motor horsepower is required. The counterweight is a collection of metal weights that is equal to the weight of the car containing about 45% of its rated load. A set of chains are looped from the bottom of the counterweight to the underside of the car to help maintain balance by offsetting the weight of the suspension ropes.

Guide rails that run the length of the shaft keep the car and counterweight from swaying or twisting during their travel. Rollers are attached to the car and the counterweight to provide smooth travel along the guide rails.

The traction to raise and lower the car comes from the friction of the wire ropes against the grooved sheaves. The main sheave is driven by an electric motor.

Most elevators use a direct current motor because its speed can be precisely controlled to allow smooth acceleration and deceleration. Motor-generator (M-G) sets typically provide to dc power for the drive motor. Newer systems use a static drive control. The elevator controls vary the motor's speed based on a set of feedback signals that indicate the car's position in the shaftway. As the car approaches its destination, a switch near the landing signals the controls to stop the car at floor level. Additional shaftway limit switches are installed to monitor overtravel conditions. more

Elisha Otis
Elisha Otis invented the "Improvement in Hoisting Apparatus." Elisha Otis didn't actually invent the elevator, he invented the brake used in modern elevators. His brakes made skyscrapers a practical reality. (above illustration - patent drawing of the Elisha Otis elevator)

Elisha Otis
Elisha Otis was inspired to design what was then called the "safety elevator".

History of Elevators
By 1850, steam and hydraulic elevators had been introduced, but it was in 1852 that the landmark event in elevator history occurred: the invention of the world's first safety elevator.

Elevator History
Rudimentary elevators, or hoists, were in use during the Middle Ages and can be traced back to the third century BC. They were operated by animal and human power or by water-driven mechanisms.

The History of Elevators
A device for vertical transportation of passengers or freight to different floors or levels, as in a building or a mine. The term elevator generally denotes a unit with automatic safety devices; the very earliest units were called hoists.

Elevator Museum Timeline
The question is often asked of those within the elevator industry, "When and where was the elevator invented and by whom?" This would elicit the same response if the question concerned the birth of the ship, automobile, locomotive or aircraft. All such complex machines are the brainchildren of countless innovators.

Alexander Miles
Alexander Miles patented an electric elevator (U.S. pat#371,207) on October 11, 1887.

Related Innovations
Escalator
Skyscrapers

©Mary Bellis