Panoramic View Unfolding Before the Eyes Spiral-moving Escalator

Do you know about the “spiral escalators” that go up and down along a curved path like a spiral staircase? These escalators, which leisurely go up and down while detouring in the shape of a semicircle, makes the scenery before one’s eyes change like a panorama, allowing its riders to enjoy a distinctive feeling. There are only 91 of these escalators in the world, manufactured by just one Japanese company.

Spiral escalator installed in Las Vegas, United States, at Forum Shops　©Shinkenchiku-sha Co., Ltd.

Thought unrealizable before

Spiral escalator installed at the front entrance of Mitsubishi Electric Inazawa Works

“The desire to make a new and interesting escalator that nobody else has realized”—This was the wish of the company’s engineers that launched the development of the spiral escalator in 1982.

　Escalator was first introduced to the world at the Paris Exposition in 1900, although the idea of moving steps on a curved path existed from before. But engineers back then could not make a device that would operate safely. Why not? The reason is said to be because they thought both straight lines and curves operated under the same principle.

Struggles of the Engineers

　To begin with, in standard escalators, the steps on which people stand are operated by a mechanism in which the axes of two aligned rows of chains move up and down. These steps simply move together with the chain—at first they are flat, then they make a slope, and they become flat again at the end. However, in curved escalators, each step moves in a more complex manner, not only moving up and down but also tracing the shape of semicircle. In the past, some experts believed that escalators will not move in a curve unless the step-moving chains could freely expand and contract.

Overturning Common Sense

Image of a spiral escalator operated while moving the three center points

　It is said that Japanese engineers conducted numerous calculations over and over again, drawing out over 1000 blueprints, in order to solve this difficult problem. Eventually, they found out that the blueprint should be drawn by providing separate center points to the three parts with varying slopes. This thought process was based on making a device just by changing the length of the chains, without requiring them to be expanded or contracted. Overturning the common sense of drawing a blueprint based on the thought that there is only one center because the escalator moves in the shape of a circle and devising a moving center led to the advancement of technology.

Like a Work of Craft

Image of the step-supporting framework. The lengths inside and outside of the chain are different so that it can be moved in a semicircle shape.

The blueprint is not the only outstanding aspect of spiral escalators. There are many devices incorporated into parts, such as the step’s shape and the framework that supports and moves the steps from behind, in order for the escalator to be actually operated.

　For example, let’s take a look at the steps. In standard escalators, the steps have a rectangular shape, but in the curved escalators, the inside of the curve is a little shorter, making a fan-like shape. Upon closer observation, you should readily notice that the fine grooves carved into the part on which the steps are placed are also not straight, but the outside of the curve slightly bulges. This is one of the devices for all the steps to be operated smoothly in a curve.

Engineers inspecting the rails that move the steps

In addition, the rollers on both sides of the steps supporting their movements like the wheels of a car have also been made into a ball-like shape. The spherical rollers move like the tip of a ball-point pen, making the complex three-dimensional movement smooth.

　The rail on which the rollers move can be bent manually. Only because the spiral escalators are carefully assembled like the work of a craft by the hands of veteran engineers can they be operated safely and comfortably.

Monument that Decorates Space

Two spiral escalators placed symmetrically in Yokohama Landmark Plaza

The spiral escalator debuted at The International Exposition held at Tsukuba, Japan, five years after the development started. Since then, 36 units have been installed in Japan, and 55 units have been exported overseas, including the U.S., Canada, Singapore, China, Thailand, Saudi Arabia, Qatar, and United Arab Emirates.

　This marvelous escalator is not only installed as a machine for simply going up and down, but as a unique monument that decorates space in plazas and buildings.