Escalator Drive Chain Tensioning With Self-Adjusting Pressing Blocks

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Solution Overview

Problem

The handrail band drive chain in escalator systems loosens over time, requiring frequent adjustments to pivot points and guiding rolls, leading to heavy maintenance work and quality issues.

Innovation Solution

A tension device with pressing blocks and a support assembly that applies pressure to the drive chain using weights or pre-loaded springs, allowing for automatic tensioning without the need for periodic adjustments to pivot points.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Duration of action of stationary object

If the drive chain is used for an extended period, then the handrail system operates continuously, but the drive chain loosens requiring periodic adjustments

Engineering Contradiction:
Improveoperating durationVSAvoidchain tension stability
Core Design Contradiction:
Duration of action of stationary objectVSReliability

Solution Approach 1:

The patent applies a dynamic tensioning mechanism where the distance between pressing blocks can be adjusted. The connecting rods with hinges allow the pressing blocks to move dynamically, maintaining optimal chain tension as the chain loosens over time, rather than using a fixed static structure

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The tension device performs preliminary tensioning action on the drive chain before it becomes excessively loose. By continuously applying pressing force through the pressing blocks, the system prevents the chain from reaching a state requiring manual intervention, maintaining tension proactively throughout operation

Inventive Principle:
Principle #10Preliminary action

2Reliability

If pivot points are moved to tension the chain, then chain tension is restored, but heavy maintenance work is required

Engineering Contradiction:
Improvechain tensionVSAvoidmaintenance workload
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The tension device is self-regulating through its mechanical design. As the drive chain loosens, the pressing blocks naturally move closer together via the hinge mechanism, automatically applying increased tension without requiring external intervention. The system serves itself by detecting and correcting tension loss

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The pressing blocks act as intermediary elements between the fixed support structure and the moving drive chain. Rather than moving the entire pivot point or drive wheel, the pressing blocks provide localized tensioning force at multiple points along the chain, simplifying the maintenance requirement

Inventive Principle:
Principle #24Intermediary (Mediator)

3Extent of automation

If pressing blocks are used to tension the chain, then automatic tensioning is achieved, but device complexity increases

Engineering Contradiction:
Improveautomatic tensioningVSAvoidtension device structure
Core Design Contradiction:
Extent of automationVSDevice complexity

Solution Approach 1:

The tension device is segmented into modular components: support assemblies mounted on the frame, connecting rods with hinges, and pressing blocks that contact the chain. Each segment performs a specific function and can be independently adjusted or replaced, managing complexity through functional decomposition

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Instead of moving the drive wheel pivot point outward to tension the chain (conventional approach), this invention applies pressing force inward from both sides of the chain. The pressing blocks move toward each other to compress the chain laterally, creating tension through a reverse mechanical action

Inventive Principle:
Principle #13The other way round (Inversion)

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

Eliminates the need for frequent adjustments to pivot points and guiding rolls, reducing maintenance work and improving the quality of the handrail system by maintaining chain tension automatically and reliably.

Implementation Method 1

a weight applies pressures to the connecting rods

Methodology Applied
Scientific EffectGravity: Gravitation

Implementation Method 2

a pre-loaded spring applies pressures to the connecting rods

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3461781B1Tension device for drive chain, method and escalator system using same
Publication Date: 2024.07.24 KONE OYJ
  • EP3461781B1 patent drawingFigure 1
  • EP3461781B1 patent drawingFigure 2
  • EP3461781B1 patent drawingFigure 3

AI summary

The present disclosure discloses a tension device (2) for a drive chain (11) of a handrail system (1) of an escalator system, a method and an escalator system including the same. The tension device (2) for the drive chain (11) applies pressures in opposite directions to a drive chain (11) so as to make portions of the drive chain (11) close to each other to tension the drive chain (11). The pressures are applied to the drive chain (11) via a weight (5) or a pre-loaded spring (5'). The present disclosure also provides a method for tensioning a drive chain. The present disclosure can eliminate loosening of the drive chain after running several months, eliminate periodic heavy work on site for the escalator system and a drive system comprising the drive chain, and improve quality thereof in a simple, reliable and low cost manner.