How escalator work

ESCALATOR

An escalator is really just like a conveyor belt. The stairs are pulled around in a loop by a pair of chains. What’s tricky about escalators is keeping the steps level while they’re going up the slope (so you’re not tilted). The other trick is getting them to stay level at the beginning and end of the ride so people can get on and off safely.

Escalator steps have two sets of wheels. One set is at the top of each stair, and is pulled by the chains. At the bottom of the step is another set of wheels that runs along a metal pathway (like train tracks). The pathway is sloped between floors, but at the top and bottom of the rise, the track becomes flat before going around and back down, below the floor. When the steps are coming up the slope, each one is higher than the one before, like stairs, but when they reach the level part, they flatten out.

History

The first patent relating to an escalator-like machine was granted in 1859 to a Massachusetts man for a steam driven unit. On March 15 1892, Jesse Reno patented his moving stairs or inclined elevator as he called it. In 1895, Jesse Reno created a new novelty ride at Coney Island from his patented design, a moving stairway that elevated passengers on a conveyor belt at a 25 degree angle.

The escalator as we know it was later re-designed by Charles Seeberger in 1897, who created the name 'escalator' from the word 'scala', which is Latin for steps and the word 'elevator', which had already been invented.

Charles Seeberger, together with the Otis Elevator Company produced the first commercial escalator in 1899 at the Otis factory in Yonkers, N.Y. The Seeberger-Otis wooden escalator won first prize at the Paris 1900 Exposition Universelle in France. Jesse Reno's Coney Island ride success briefly made Jesse Reno into "the" escalator designer and he founded the Reno Electric Stairways and Conveyors company in 1902.

Charles Seeberger sold his patent rights for the escalator to the Otis Elevator Company in 1910, who also bought Jesse Reno's escalator patent in 1911. Otis then came to dominate escalator production, and combined and improved the various designs of escalators.

According to Otis, "In the 1920s, Otis engineers, led by David Lindquist, combined and improved the Jesse Reno and Charles Seeberger escalator designs, and created the cleated, level steps of the modern escalator in use today. Over the years, Otis dominated the escalator business, but lost the product's trademark. The word escalator lost its proprietary status and its capital "e" in 1950 when the U.S. Patent Office ruled that the word "escalator" had become just a common descriptive term for moving stairways."

How it work

The core of an escalator is a pair of chains, looped around two pairs of gears. An electric motor turns the drive gears at the top, which rotate th­e chain loops. A typical escalator uses a 100 horsepower motor to rotate the gears. The motor and chain system are housed inside the truss, a metal structure extending between two floors.

Instead of moving a flat surface, as in a conveyer belt, the chain loops move a series of steps. The coolest thing about an escalator is the way these steps move. As the chains move, the steps always stay level. At the top and bottom of the escalator, the steps collapse on each other, creating a flat platform. This makes it easier to get on and off the escalator. In the diagram below, you can see how the escalator does all of this.

Each step in the escalator has two sets of wheels, which roll along two separate tracks. The upper set (the wheels near the top of the step) are connected to the rotating chains, and so are pulled by the drive gear at the top of the escalator. The other set of wheels simply glides along its track, following behind the first set.

The tracks are spaced apart in such a way that each step will always remain level. At the top and bottom of the escalator, the tracks level off to a horizontal position, flattening the stairway. Each step has a series of grooves in it, so it will fit together with the steps behind it and in front of it during this flattening.

In addition to rotating the main chain loops, the electric motor in an escalator also moves the handrails. A handrail is simply a rubber conveyer belt that is looped around a series of wheels. This belt is precisely configured so that it moves at exactly the same speed as the steps, to give riders some stability.

The escalator system isn't nearly as good as an elevator at lifting people dozens of stories, but it is much better at moving people a short distance. This is because of the escalator's high loading rate. Once an elevator is filled up, you have to wait for it to reach its floor and return before anybody else can get on. On an escalator, as soon as you load one person on, there's space for another.