elevator

elevator in machinery, device for transporting people or goods from one level to another. The term is applied to the enclosed structures as well as the open platforms used to provide vertical transportation in buildings, large ships, and mines; it is also applied to devices consisting of a continuous belt or chain with attached buckets for handling bulk materials. Simple hoists were used from ancient times. From about the middle of the 19th cent., power elevators, often steam-operated, were used for conveying materials in factories, mines, and warehouses. In 1853 the American inventor Elisha G. 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 and served as an impetus to the industry. Otis established a company for manufacturing elevators and patented (1861) a steam elevator. After the introduction by Sir William Armstrong of the hydraulic crane (1846), the hydraulic principle was applied to the elevator, 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. As improvement of design made increased speed of movement possible, various safety devices, such as speed governors, were developed. Toward the end of the 19th cent., electric elevators came into use, and operation by electric motor gradually became the chief method. Later improved safety devices were added, and automatic and partly automatic elevators were introduced. Increase in speed of operation and improvement in general design also characterize the more modern elevators.

elevator. Means by which loads or people can be moved vertically in a chamber within a shaft from one floor of a building to another, called lift in the UK. Although primitive lifts were known in the early C19 (e.g. in the Bunker Hill Monument, Charlestown, MA (1824–42, by Willard), more sophisticated examples were in use in the USA by the 1850s, and Post's Equitable Life Assurance Building, NYC (1868–70—demolished) was one of the first office buildings to be equipped with elevators. Hydraulic power was used for a time, and by the 1880s electrically-powered lifts were evolving, so that by the end of C19 their use was widespread, facilitating the development of tall buildings. See also grain elevator.

Bibliography

C. Elliott (1992)

elevator (el-i-vay-ter) n.
1. an instrument that is used to raise a depressed broken bone. periosteal e. an instrument used in orthopaedics to strip the fibrous tissue (periosteum) covering bone.

2. a lever-like instrument used to ease a tooth or root out of its socket during extraction.