How do escalators work

Escalator scissors

An escalator has a structural support called the “escalator truss” on which all the mechanisms are located and attached. The escalator truss consists of three main sections: Upper Section, Incline Section, and Lower Section. Usually, the Upper and Lower sections are fixed, while the center section can be modified to provide variable heights.

The escalator truss has two support angles at each end where it is inserted into the structural beams of the building. The support angles are not fixed (not welded, screwed, etc.) and are held only by their own weight.

Escalator truss material is made of various steel alloys and shapes (rectangular steel, angle steel and channel steel) and combinations of these in various sizes.

For cladding of escalator trusses for internal escalators, paint, semi-open, fully open and heavy escalators (as per BS 729 – ISO1461) are hot zinc coated to ensure longer life with a minimum thickness of 85 microns.

Tracking system

Inside the cage is a rail system that determines the direction of the steps. The rail system consists of three main parts: the Upper rail, the Inclined rail and the Lower rail. The rail system is responsible for guiding the chain of steps and rungs, ensuring that they move smoothly in the direction of travel. It also helps the step chain and rungs to turn properly at transitions and forms a loop.

Drive unit

At the top of the escalator is the main drive shaft, which consists of major parts such as stepped chain wheels, a drive sprocket and a main axle with a gear mounted on it. The drive motor and gearbox transmits the drive force to the drive sprocket through a bi-directional drive chain and makes it move at a certain speed specified in the standard called “Permitted Rated Speed”. The rotation of the drive sprocket causes the main drive shaft to rotate and therefore causes the wheels of the step chain to rotate. The step chain consists of two sets of roller chains mounted on the step chain wheels, connected by several axles at regular intervals. Eventually, the steps mounted on the step chain axles begin to rotate.

Handrail design

On both sides of the steps, depending on the purpose of the escalator and the taste of the customer, there are glass or stainless steel handrails, called “Handrails”, on which rubber handrails, called “Handrails”, are attached. For the safety of the passengers, the handrails are provided so that they can hold on and maintain their balance.

Behind the main drive shaft is the handrail drive axle, which consists of a handrail drive shaft with major components mounted thereon, such as a friction wheel and a sprocket.

A chain from the main axle sprocket of the main drive shaft transmits driving force to the handrail axle sprocket and causes the handrail drive shaft to rotate. A friction wheel located on either side of the handrail drive shaft is located inside the handrail and moves the handrail. In order to firmly attach the handrail to the friction wheel, a belt consisting of several rollers, called the “handrail pressure belt”, is attached under the handrail. This pressure belt creates the frictional force necessary to rotate the handrail. In addition, there are several rollers in front of and after the friction wheel, called the “handrail tensioning apparatus”, which performs the task of tensioning the handrail on both sides of the friction wheel.

To ensure safety, there is a safety circuit consisting of safety contacts and control devices that stop the device in emergency situations, protect passengers and prevent damage to the escalator.