Analysis mechanics tape escalator step

Tape escalator steps, designed for heavy loads, at higher stresses and strains compared with escalators, designed for smaller loads. Powerful escalators designed for public transport systems, which are characterized by high density of passenger traffic, especially during the hours of «peak» and special events.

The escalator two shafts: upper and idle. The upper shaft is driven by a chain that is connected with the motor through a gearbox. Single shaft placed in the carriage, which extends linearly with respect to the farm by a spring and a tension rod. When the carriage is pulled back, it keeps the chain and band levels are constantly strained. Policy type «Stand right» does not promote even wear across the width of the chain mechanism: on the one of the chains have a greater force, and, consequently, wear than the other chain.

Chain belt levels allow to maintain a safe and efficient clearance between the stages, as well as between the steps and the rim. Chain escalators designed for heavy loads, considerably stronger chains escalators designed for small loads. The wheels are provided, arranged at a pitch approximately equal to the width of the stage. The two chains are connected by transverse axles in places where the steps are mounted via hinges. Steps can rotate freely around the axis.

While new chain, they accurately correspond to each other along the length and accuracy. Two chains with high accuracy are two sprockets at the upper and idle shafts. High accuracy matching chains and sprockets ensures correct positioning stages with respect to each other and perpendicular position relative to the axial line of the mechanism.

The carriage is located at the bottom of the installation site idler pulley to keep the chain taut constantly. The tension should be the same for both chains, but usually it does not happen during operation of the escalator. The load of passengers is not distributed evenly across the belt levels (due to the aforementioned policy). This leads to more efforts on one of the chains, as a result there is a high increase in depreciation and precise execution tolerances and gaps in the bushes chain. High wear one of the chains allows the stairs to lean to one side of the mechanism. The bigger the chain of the escalator with a great lifting height, the more wear and tear, causing more bias levels. The problem becomes a serious imbalance when facing the wrong stage trying to get through the escalator comb. It can affect the safety of passengers, especially when you consider the possibility of impact on the level of a comb or a collision steps.

High wear one of the strands may cause the chain to kink, especially at the exit idler shaft sprocket teeth. The bends create significant load on the circuit and the stage. Direct aims to prevent the appearance of bending, forcing the chain to remain in a horizontal position. However, this further increases the high mechanical load.

In the gap between the lower platform and the lower rotating stage at the reverse side are rotated in accordance with elevation rails. Such steps allow lean swings at an angle that facilitates the movement of the upper pivot on the reverse side. This maneuver puts additional stress level.

Impact wear chains underlines the huge difference between the stages with pin and transverse axis. In step with pin wear adversely affects the nearby circuit on both sides of the stage. In this connection, the stage assumes the difficulties associated with the need to adapt to the difference in the forces acting on the opposite side of the step. Stage with a transverse axis is not exposed to differential forces since such differential axis is absorbed. Operation escalators with a large lifting height for a long time on the ascent or descent increases the wear on chains, especially when alternating the direction of the escalator. Frequent use of monitoring systems such as Smart Step and differential circuit can help in identifying the critical points along the entire length of the escalator, especially when planning maintenance schedules.

Subsequent articles will be given more facts and technical data, explaining what is happening inside the escalator (especially designed for heavy loads). It will propose a new design of the carriage. This is useful for the industry, since it would maintain escalators in good working condition, control the maintenance schedule, reduce refurbishment costs, improve safety and, most importantly, will enable the designer to understand what is happening inside the escalator.

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