|
Creative Elevators
|
In the middle 1800s, there were many types of crude elevators that carried freight. Most of them ran hydraulically. The first hydraulic elevators used a plunger below the car to raise or lower the elevator. A pump applied water pressure to a steel column inside a vertical cylinder. Increasing the pressure caused the elevator to ascend. The elevator also used a system of counter-balancing so that the plunger did not have to lift the entire weight of the elevator and its load. The plunger, however, was not practical for tall buildings, because it required a pit as deep below the building as the building was tall. Later, a rope-geared elevator with multiple pulleys was developed.
Henry Waterman of New York is credited with inventing the "standing rope control" for an elevator in 1850.
In 1852, Elisha Otis introduced the safety elevator, which prevented the fall of the cab if the cable broke. The design of the Otis safety elevator is somewhat similar to one type still used today. A governor device engages knurled roller(s), locking the elevator to its guides should the elevator descend at excessive speed. He demonstrated it at the New York exposition in the Crystal Palace in a dramatic, death-defying presentation in 1854.
On March 23, 1857 the first Otis passenger elevator was installed at 488 Broadway in New York City.
|
|