The Elevator reference article from the English Wikipedia on 24-Jul-2004
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Elevator

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An elevator is a transportation device used to move goods or people vertically. In British English and Australian English, elevators are known more commonly as lifts, although the word elevator is familiar from American movies and television shows.

Table of contents
1 History
2 Types of elevators
3 Special operating modes
4 Floor numbering
5 Dumb waiter
6 Material handling belts
7 Aircraft terminology
8 See also

History

Elevators began as simple rope or chain hoists. An elevator is a hoist contained within an elevator well. An elevator consists of a cab ("cage") or platform, the ropes or cables required to raise and lower it using pulleys, and machinery to move the rope. Later refinements included steam power and hydraulic power.

In 1853, Elisha Otis introduced the safety elevator, which prevented the fall of the cab if the cable broke, and on March 23, 1857 his first elevator was installed at 488 Broadway in New York City. The first elevator shaft preceded the first elevator by four years. Construction for Peter Cooper's Cooper Union building in New York began in 1853. An elevator shaft was included in the design for Cooper Union, because Cooper was utterly confident a safe passenger elevator would soon be invented: the shaft however was circular because Cooper felt it was the most efficient design. Later Otis designed a special elevator for the school. Today the Otis Elevator Company, now a subsidiary of United Technologies Corporation, is the world's largest manufacturer of vertical transportation systems.

The first electric elevator was built by Werner von Siemens in 1880. The safety and speed of electric elevators were significantly enhanced by Frank Sprague.

The development of elevators allowed easy access to the upper storeys of tall buildings and skyscrapers.

Types of elevators

In general, there are three types of elevators:

Traction type

Hydraulic type

Paternoster

A special type of elevator is the paternoster, a constantly moving chain of boxes. A similar concept moves only a small platform, which the rider mounts while using a handhold and was once seen in multi-story industrial plants.

Special operating modes

In areas with large populations of observants Jews, one may find a "Sabbath Elevator" which will stop automatically at every floor in turn. This allows people to step on and off without pressing buttons to summon the elevator or indicate the desired floor and thus violating the Sabbath prohibition against doing work.

Floor numbering

In general, elevator call buttons are numbered one-by-one to indicate the floors or landings that they cause the car to move to. However, there are some conventions to be aware of. The most important are:

Designations such as B1 and B2 for basement 1 and 2 have also been observed. B2 seems to mostly refer to the floor below B1, though the reverse may also be encountered. The relative position of the buttons usually shows which way it is.

Dumb waiter

A small box elevator designed for the carriage of goods only is called a dumb waiter.

Material handling belts

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.

When such mechanisms (or spiral screws or pneumatic transport) are used to elevate grain for storage in large vertical silos, the entire structure is called a grain elevator,

Aircraft terminology

The surface immediately behind the final A of the registration G-ASBA is the horizontal stabilizer. The drooped surface hinged to it is the elevator. The aircraft is a 1966 Currie WotEnlarge

The surface immediately behind the final A of the registration G-ASBA is the horizontal stabilizer. The drooped surface hinged to it is the elevator. The aircraft is a 1966 Currie Wot

Elevators are also control surfaces, usually at the rear of aircraft, which control the aircraft's orientation by changing the pitch of the aircraft, and so also the angle of attack of the wing. An increased angle of attack will cause a greater lift to be produced by the profile of the wing, and (if no power is added or available), a slowing of the aircraft. A decreased angle of attack will produce an increase in speed (a dive). In some aircraft the elevator is in the front of the aircraft, ahead of the wing. (This type of configuration is called a "canard", the french word for duck.) The Wright Brothers' early aircraft was of this type. The canard type is more efficient, since the forward surface produces upward lift. The main wing is also less likely to stall, as the forward control surface is configured to stall before the wing, causing a pitch down and reducing the angle of attack of the wing. The elevator may be the only pitch control surface present or it may be hinged to a fixed or adjustable surface called a stabilizer.

See also