Magnetic Sensor Handrail Tension Monitoring

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Solution Overview

Problem

The installation and monitoring of moving handrails in passenger conveyors, such as escalators and moving walkways, are time-consuming and unreliable due to the need for manual adjustment and reliance on expert engineers, often requiring post-installation maintenance and repair to address tension issues that can affect safety and longevity.

Innovation Solution

A moving handrail monitoring system using magnetic sensors to detect changes in magnetic flux and calculate tension, with a controller that provides output signals and alerts for over-tensioned or under-tensioned conditions, integrated with a control station for predictive maintenance and remote monitoring.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If manual adjustment of drive components and support structure components is used to set handrail tension during installation, then the installation can be completed, but the process is extremely time consuming and unreliable

Engineering Contradiction:
Improvehandrail tension setting reliabilityVSAvoidinstallation time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent replaces manual mechanical adjustment of drive components with an automated magnetic sensor-based monitoring system. The magnetic sensor detects changes in magnetic flux caused by handrail motion and provides data to a controller that automatically determines tension status, eliminating the need for time-consuming manual trial and error adjustment while improving reliability through objective measurement rather than subjective engineer judgment

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The handrail tension monitoring system enables the system to self-diagnose tension issues through automatic detection by magnetic sensors and analysis by the controller. The system provides real-time feedback about handrail tension status without requiring external engineer intervention, allowing for immediate identification and correction of tension problems during and after installation

Inventive Principle:
Principle #25Self-service

2Strength

If the moving handrail is over-tensioned, then the handrail is secure, but this results in overheating of the handrail, accelerated wear and reduced service life

Engineering Contradiction:
Improvehandrail tensionVSAvoidservice life
Core Design Contradiction:
StrengthVSDuration of action of stationary object

Solution Approach 1:

The magnetic sensor continuously monitors handrail position and motion, providing real-time feedback to the controller about actual handrail tension conditions. This feedback loop enables automatic detection of over-tensioning before it causes damage, allowing for immediate correction by adjusting the drive mechanism to reduce tension to optimal levels, thereby preventing overheating and accelerated wear

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system transitions from static manual tension setting to dynamic automated monitoring and adjustment. The magnetic sensor continuously tracks handrail motion and the controller dynamically adjusts tension in real-time based on actual operating conditions, ensuring tension remains within optimal ranges that balance security with prevention of overheating and wear

Inventive Principle:
Principle #15Dynamics

3Ease of operation

If the moving handrail is under-tensioned, then the handrail is easy to move, but this results in the moving handrail running at a different speed to the conveyance band, which can cause a risk to passengers' safety

Engineering Contradiction:
Improvehandrail adjustabilityVSAvoidpassenger safety
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The magnetic sensor provides continuous feedback on handrail position and speed relative to the conveyance band. The controller uses this feedback to detect speed discrepancies that indicate under-tensioning, automatically adjusting the drive mechanism to synchronize handrail speed with conveyance band speed, thereby eliminating safety risks while maintaining ease of automatic adjustment

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system replaces manual mechanical tension adjustment with automated electronic control based on magnetic sensor data. The controller automatically adjusts drive component settings to achieve proper tension and speed synchronization, eliminating the need for manual intervention while ensuring passenger safety through precise speed matching between handrail and conveyance band

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

4Reliability

If a proximity sensor is positioned beneath the handrail for detection of a disengaged handrail, then the disengaged handrail can be detected, but this only stops the walkway rather than providing comprehensive tension monitoring

Engineering Contradiction:
Improvehandrail disengagement detectionVSAvoidmonitoring system capability
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The magnetic sensor serves multiple functions simultaneously: it detects handrail disengagement, monitors handrail tension, measures handrail speed, and tracks handrail position. This single sensor replaces the need for multiple separate sensing systems, providing comprehensive monitoring capability while reducing overall system complexity through multi-functionality

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 system enables faster and more reliable installation, proactive maintenance, and reduced service costs by providing accurate tension data and alerts, reducing the risk of handrail-related issues and improving conveyor availability.

Implementation Method 1

at least one magnetic sensor provided adjacent to a moving handrail of the passenger conveyor, wherein the or each magnetic sensor is configured to detect a change in magnetic flux resulting from motion of the moving handrail

Methodology Applied
Scientific EffectMagnetic flux change: Magnetic Field

Implementation Method 2

determine a change in a distance between a surface of the handrail and the magnetic sensor based on the variation in the output signal from the magnetic sensor

Methodology Applied
Scientific EffectMagnetic flux variation for distance measurement: Magnetic Field

Data Source

PatentEP3825272B1Monitoring of moving handrails for passenger conveyors
Publication Date: 2023.07.05 OTIS ELEVATOR CO
  • EP3825272B1 patent drawingFigure 1
  • EP3825272B1 patent drawingFigure 2~3
  • EP3825272B1 patent drawingFigure 4

AI summary

A moving handrail monitoring system (60) for a passenger conveyor (10) comprises at least one magnetic sensor (62) provided adjacent to a moving handrail (22) of the passenger conveyor (10), wherein the or each magnetic sensor (62) is configured to detect a change in magnetic flux resulting from motion of the moving handrail (22) and provide an output signal. A controller (64) is coupled to the or each magnetic sensor (62). The controller (64) is configured to: receive the output signal from the magnetic sensor (62), determine a change in a distance (X) between a surface (25) of the handrail (22) and the magnetic sensor (62) based on the variation in the output signal from the magnetic sensor (62); and calculate a handrail tension based on the change in distance (X).