Escalators

TECHNOLOGY

“ The real ingenuity of this moving staircase comes in the way the steps flatten at the top and bottom”

How escalators work

Unveiling the mechanics that powers these moving staircases

An escalator is essentially made up of a series of interlocking steps, wheelmounted on a chain, which in turn is powered by an electric motor.

The real ingenuity of this moving staircase comes in the way the steps flatten at the top and bottom, before splaying out into solid steps for users to stand on.

As the steps are pushed along the rail, they are raised up, each resting against the next. There are two sets of wheels: the first attached to the chain, pulling the steps along, and the second are free, but positioned in such a way as to keep the steps level. As the mechanism reaches the end of the escalator, the chain levels out, and the steps follow suit to make it easier to disembark.

As the steps disappear from sight, they rotate around the drive gear, interlocking through carefully placed grooves. The steps then travel back to the start of the escalator upside down, underneath the visible part of the machine, before starting their journey again.

On the reverse end of the escalator, the steps level out before becoming defined steps again as they ascend the angled chain. The handrail runs off the same drive mechanism, rotating around a stationary rail.

Escalators do not require much power to run; a typical machine needs only a 7.5-kilowatt (ten-horsepower) engine to operate – about the same as three small lawnmowers.

Stairs on the move

Take a look inside this short-haul transport system

Raised steps

The angle created by the chain pushes each step up, with stabilising wheels keeping them in shape so they don’t collapse once weight is placed on top.

Flat steps

These are on a level part of the chain to allow for easy access. Steps interlock using a series of grooves.

Handrail

Uses the escalator’s motor to rotate at the same speed as the steps.

Motor

This powers the escalator, generally providing around 7.5kW (10hp).

Return wheel

The steps rotate around this cog before returning to the visible part of the system.

This history of the motorised staircase spans over a century of incremental improvements, leading to today’s escalators

Drive mechanism

Attached by a belt to the motor, this rotates, pulling the steps and handrail around.

Inner rail

A track on which the steps run; this is what keeps them level during the ascent.

Outer rail

The rail, which is fixed on to the steps, drives them around.

The rise of escalators

Jesse Reno, an inventor hailing from Kansas in the USA, patented the escalator on 15 March 1892. He designed it more as an entertaining novelty, rather than a practical transport system, with the first machine being installed along the famous Old Iron Pier and the amusement park in Coney Island, Brooklyn.

Five years later, however, Charles Seeberger redesigned the moving staircase and installed the first-ever commercial escalator in the Otis Elevator Company’s factory itself. Otis bought out the patents of both Seeberger and Reno, positioning the company as the foremost producer of commercial escalators, a status they have held to this day, with their escalators found in shopping centres, airports and train stations all over the world.