Introduction:Whether at the mall or at the airport, escalators are used on a regular basis. They are often taken for granted, but are actually the most expensive and biggest machines used by people regularly. Based on the inclined belt, the escalator is actually a very simple device. Stairs are pulled by rotating chain loops, making a very effective way for transporting a lot of people over a short distance. A specialized form of the escalator is moving ramps or sidewalks (travelators). These travelators move people and materials horizontally.History:The Escalator is based on the inclined belt invented by Jesse W. Reno in 1891. This had an ...view middle of the document...
The escalator was first introduced at the Paris Exhibition of 1900, where it won first place.How it Works:As shown on the picture on the left, the escalator is basically a pair of chains that are looped around two pairs of gears. An electric motor turns the drive gears that are located at the top. The drive gears rotate the chain loops. The truss, a metal box between two floors, houses the motor and chain system. The chain loops move a series of steps, instead of a flat surface as in a conveyer belt. As you know from experience, the steps will always stay level. At the entrance and exit to the escalator (top and bottom), the steps will collapse together and form a flat platform. The platform helps people get on and off the escalator.The steps that form the elevator, as shown in the picture on the left, each has two sets of wheels. These wheels roll along two different tracks. At the top of the escalator, rotating chains pulled by the drive gear connect to the upper set of wheels (the wheels near the top of the step). The second set of wheels is used for returning the step to the bottom of the escalator. They just glide down the track. You can see where the wheels go on the different tracks, in the expanded portion in the diagram on the left.A plastic conveyer belt is used as the handrail. It moves at exactly the same speed as the steps, giving added stability. The handrail is looped around a series of wheels and is turned by the same electric motor that moves the steps.