Elevator Suspension Member Pre-Tensioning for Twist-Free Tracking

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Solution Overview

Problem

Elevator suspension members with tension members encased in a compressible polymer jacket experience twisting and tracking issues due to unequal permanent stretch during operation, leading to misalignment and reduced performance.

Innovation Solution

Pre-tensioning the elevator suspension member by applying a controlled load to adjust the low load elongation of tension members before operation, using methods such as passing the members over sheaves or adding weight to the elevator car during installation, to equalize elongation and prevent permanent deformation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If tension members are used in elevator suspension members, then the suspension member can support the elevator load, but individual tension members experience unequal permanent stretch during operation causing twisting and tracking issues

Engineering Contradiction:
Improveload support capabilityVSAvoidtracking stability
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The patent applies preliminary action by pre-tensioning the tension members during manufacturing or installation before the elevator suspension member is put into service. This pre-tensioning equalizes the elongation characteristics of individual tension members, preventing unequal permanent stretch and subsequent twisting or tracking issues during operation.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent utilizes parameter changes by modifying the tension characteristics of tension members through pre-tensioning. This changes the elongation parameters of individual tension members to be more uniform, which resolves the tracking stability issue while maintaining the load support capability.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If pre-tensioning is applied to adjust low load elongation of tension members, then twisting and misalignment are reduced, but additional processing steps are required during manufacturing or installation

Engineering Contradiction:
Improveoperational reliabilityVSAvoidinstallation complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The pre-tensioning process is performed as a preliminary action during manufacturing or installation, equalizing the elongation of tension members before the suspension member enters service. This eliminates the need for complex adjustment mechanisms during operation, as the tension members are pre-conditioned to have uniform elongation characteristics.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The pre-tensioning process allows the suspension member to self-adjust and equalize tension distribution across tension members during the pre-tensioning phase. This self-service mechanism reduces the need for external adjustment devices or complex control systems during operation.

Inventive Principle:
Principle #25Self-service

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

Pre-tensioning reduces twisting and misalignment, improving the performance and lifespan of elevator belts by ensuring equal elongation of tension members, thereby enhancing operational reliability and reducing downtime.

Implementation Method 1

pre-tensioning an elevator suspension member to adjust low load elongation of tension members within the elevator suspension member

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP4647384A1Twist resistant elevator suspension member
Publication Date: 2025.11.12 OTIS ELEVATOR CO
  • EP4647384A1 patent drawingFigure 1~3B
  • EP4647384A1 patent drawingFigure 4A~5
  • EP4647384A1 patent drawingFigure 6~9

AI summary

A method and assembly includes pre-tensioning an elevator suspension member to adjust low load elongation of tension members within the elevator suspension member prior to placing the elevator suspension member in operation for an elevator.