USA HISTORY

Detailed explanation-1: -Concerned with what would happen if the elevator’s support rope broke, Otis devised what he called a “safety hoist, ” a steel wagon-spring meshing with a ratchet that ensured if the rope gave way, the spring would catch and keep the platform from plummeting and crushing everything below.

Detailed explanation-2: -Once the elevator had been optimized for popular use, it only contributed to the growth of taller and taller skyscrapers. The 1930 skyscraper study emphasizes that elevator technology was very expensive to install and maintain at that early stage of the skyscraper.

Detailed explanation-3: -It was, however, the refinement of the Bessemer process, first used in the United States in the 1860s, that allowed for the major advance in skyscraper construction. As steel is stronger and lighter in weight than iron, the use of a steel frame made possible the construction of truly tall buildings.

Detailed explanation-4: -Modern skyscrapers. Modern skyscrapers are built with steel or reinforced concrete frameworks and curtain walls of glass or polished stone. They use mechanical equipment such as water pumps and elevators.

Detailed explanation-5: -Otis created a superior device, a tough, steel wagon-spring meshing with a ratchet, and so created the elevator brake. In 1854, Otis dramatized his safety device on the floor of the Crystal Palace Exposition in New York.