An elevator or a lift is a car that moves in a vertical shaft carrying passengers or freight from one floor to another in a multi-storeyed building. Most modern elevators are propelled by electric motors with the help of a counterweight through a system of cables and pulleys. Do you know who invented the elevator?
Elevator was not invented by one man or in a single day. Its development is a result of combined efforts made by several people.
The practice of lifting loads by mechanical means during building construction goes back to Roman times. The Roman architect-engineer Vitruvius Pollio in the 1st century B.C. had described lifting platforms that used pulleys and capstans, operated by humans, animals or water power. In 1800 A.D. steam power came to be used to operate such devices in England. In the early 19th century, a hydraulic lift was introduced. These lifts were used only to hoist freights because they were most unreliable.
In 1853, Elisha Graves Otis introduced a safety device and gave birth to the first passenger elevator. This was put into service in the Haughwout Department Store in New York City in 1857. It was powered by steam. It climbed five floors in less than a minute. Improved versions of the steam – driven elevators came into use in the next three decades, but the most significant progress was made after 1889. In 1894, push button operations were introduced. After that many design improvements were made.
Once the problems of safety, speed and height were overcome, attention was turned to convenience and economy. Soon more sophisticated elevators came to cater to the need of tall buildings. Their speeds were increased to 365 m per minute. Automatic operations were also introduced by the 1950s, eliminating the need of operators.
Modern elevators are made in a variety of types for many purposes. In addition to freight and passenger operations, they are used in ships, dams and rocket launchings. They are also used in construction operations. All elevators are electrically propelled – either by cables, pulleys and counterweight, by a winding drum mechanism (low height elevators) or by an electro-hydraulic combination. The drive motor is usually an AC motor for slower speeds and DC motor for higher speeds. Modern elevators are automatic ones using various control systems. They have the safety devices also.
In most modern elevators even automatic loading and unloading devices have been incorporated. A cell button activates the automatic pick-up, the elevator arrives, the load is pulled into the car, the car goes to the proper floor and the load is discharged.
See-through elevators, rising on the outside of buildings and towers, have recently become popular. First it was the Eiffel Tower of Paris which had this kind of elevator. These elevators have glass enclosed cabs affording the passengers a bird’s eye view.