Escalator Step Guide Rail Bent Section for Speed Irregularity

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Solution Overview

Problem

Conveyors such as escalators and moving walkways experience speed irregularities in step rollers due to small sprocket wheel diameters, leading to vibrations that affect passenger comfort, and existing solutions fail to adequately suppress these irregularities without causing damage or generating dynamic shock vibrations.

Innovation Solution

The implementation of hill-shaped or valley-shaped bent sections in the step guide rail, combined with a restraining member and recesses, to guide step rollers and absorb speed irregularities, while preventing gripping and sliding friction that could damage components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If a sprocket wheel of small diameter is employed to reduce the overall thickness of the conveyor, then the size of the truss is reduced, but comparatively large speed irregularities are generated in the step rollers causing vibration and adversely affecting passenger comfort

Engineering Contradiction:

Improveoverall thickness of conveyorVSAvoidspeed irregularities and vibration

Core Design Contradiction:

Volume of moving objectVSObject-affected harmful factors

Solution Approach 1:

A bent section is introduced as an intermediary element between the step roller and the driving sprocket wheel. This bent section acts as a mediator that absorbs and dampens the speed irregularities generated by the small-diameter sprocket wheel, preventing these irregularities from being transmitted to the step roller and causing vibration. The bent section serves as a cushioning element that reconciles the conflict between small sprocket diameter and smooth step roller motion.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The bent section is positioned in advance before the step roller contacts the driving sprocket wheel, creating a cushioning effect that pre-absorbs the speed irregularities. By placing the bent section beforehand, the system prevents the harmful vibrations from occurring in the first place, rather than attempting to correct them after they are generated.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

2Object-affected harmful factors

If a bent section is provided to suppress speed irregularities, then passenger comfort is improved, but the structure becomes more complex and space-consuming

Engineering Contradiction:

Improvespeed irregularitiesVSAvoidstructure complexity

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

Instead of making the entire conveyor structure complex, the bent section is applied locally only at the specific position where the step roller interacts with the driving sprocket wheel. This localized approach provides the necessary speed irregularity suppression only where needed, without adding complexity to the rest of the conveyor system. The bent section is a focused solution rather than a comprehensive redesign.

Inventive Principle:

Principle #3Local quality

3Reliability

If the step roller is pressed against the step guide rail to ensure continuous movement, then the conveyor operates smoothly, but gripping and sliding friction occur causing damage to components

Engineering Contradiction:

Improvecontinuous movementVSAvoidcomponent durability

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The bent section introduces a curved geometry between the step roller and the step guide rail. This curvature allows the step roller to follow a gentle arc rather than being sharply constrained by the straight guide rail. The curved path reduces the contact pressure and friction between the step roller and guide rail, minimizing gripping and sliding friction while still ensuring continuous movement. The curvature acts as a stress-distributing element that protects components from damage.

Inventive Principle:

Principle #14Spheroidality (Curvature)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This solution effectively suppresses speed irregularities in step rollers, enhancing passenger comfort by maintaining smooth movement and reducing the risk of damage to the rollers and guide rail components, while allowing for a reduction in conveyor thickness.

Implementation Method 1

a pressing force in a radial direction of the step roller acts when the step roller passes this bent section

Methodology Applied

Scientific EffectCompression: Compression

Implementation Method 2

speed irregularities in the step rollers that are linked with the step chain; these speed irregularities appear as vibration of the steps

Methodology Applied

Scientific EffectSpeed irregularity absorption: Damping

Data Source

PatentUS7568571B2Conveyor device

Publication Date: 2009.08.04 TOSHIBA ELEVATOR KK

AI summary

In order to suppress speed irregularity of step rollers (5) in a passenger conveyor, a bent section (17) is formed in a step guide rail (3) and a restraining member (18) is provided upstream thereof, the shape of the height of the bent section (17) and the restraining member (18) is corrected beforehand by the amount of the compression of resilient members of the step rollers (5), which are formed with such resilient members around their shafts, by the compressive force acting between the bent section (17) and restraining member (18). Thus generation of speed irregularity of the steps (4) is suppressed and passenger comfort is improved. Also, by providing a recess (3aa) in the step guide rail (3), gripping of the step rollers (5) as they execute rolling movement along the undersurface of the restraining member (18) from below can be avoided, thereby preventing damage to the step rollers (5), restraining member (18) and step guide rail (3).