Composite Elevator Tension Member Using Fused Polymer Fibers

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Solution Overview

Problem

High-rise elevator systems face challenges in reducing the weight of tension members while maintaining strength and performance, as traditional steel cord tension elements are heavy and inefficient.

Innovation Solution

A composite tension member is formed using intermingled and fused liquid crystal polymer fibers, where a lower melting point Vectran material acts as a matrix to support higher melting point Vectran fibers, eliminating the need for an epoxy matrix and reducing weight while maintaining strength.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Weight of moving object

If traditional steel cord tension elements are used, then strength and structural integrity are maintained, but weight increases significantly

Engineering Contradiction:
Improvetension member weightVSAvoidtension element strength
Core Design Contradiction:
Weight of moving objectVSStrength

Solution Approach 1:

The patent employs composite materials by combining high-strength polymer fibers (such as Kevlar, Spectra, or Vectran) with a thermoplastic matrix material. This composite construction achieves high strength-to-weight ratio, replacing traditional steel cords while significantly reducing tension member weight. The polymer fibers provide tensile strength comparable to steel, while the thermoplastic matrix binds the fibers together, creating a lightweight yet strong tension element suitable for elevator applications.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent utilizes parameter changes by selecting polymer fibers with specific mechanical properties (high tensile strength, appropriate elasticity) and thermoplastic matrices with suitable melting points and bonding characteristics. By optimizing these material parameters, the tension member achieves the required strength performance while minimizing weight, resolving the contradiction between strength and weight.

Inventive Principle:
Principle #35Parameter changes

2Weight of moving object

If lighter weight materials are used to reduce tension member weight, then weight decreases, but structural integrity and performance may be compromised

Engineering Contradiction:
Improvetension member weightVSAvoidtension member performance
Core Design Contradiction:
Weight of moving objectVSReliability

Solution Approach 1:

The composite structure of high-strength polymer fibers embedded in a thermoplastic matrix provides both lightweight properties and reliable performance. The fibers carry the primary tensile loads while the matrix distributes stresses and maintains structural integrity, ensuring the tension member meets reliability requirements for elevator applications despite the reduced weight compared to steel cords.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent applies local quality by concentrating high-strength polymer fibers in regions subjected to maximum tensile stresses, while the thermoplastic matrix provides structural support and load distribution throughout the tension member. This localized optimization of material properties ensures reliable performance where needed most while maintaining overall lightweight construction.

Inventive Principle:
Principle #3Local quality

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

The solution results in a lightweight, high-strength tension member suitable for high-rise elevator systems, enhancing performance by reducing material weight and improving traction and durability.

Implementation Method 1

heating the polymer fibers to a melting point of the thermoplastic matrix material

Methodology Applied
Scientific EffectMelting: Melting

Implementation Method 2

fusing the polymer fibers together to form a tension element having a desired configuration

Methodology Applied
Scientific EffectFusion: Welding

Data Source

PatentEP3599307B1Composite elevator system tension member
Publication Date: 2023.10.25 OTIS ELEVATOR CO
  • EP3599307B1 patent drawingFigure 1
  • EP3599307B1 patent drawingFigure 2~2A
  • EP3599307B1 patent drawingFigure 3

AI summary

A tension element of an elevator system tension member includes a plurality of first polymer fibers of a first material extending along a length of the tension element, and a plurality of second polymer fibers of a second material different from the first material. The plurality of second polymer fibers have a melting point lower than that of the plurality of first polymer fibers. The plurality of second polymer fibers are fused to the plurality of first polymer fibers to serve as a matrix for the plurality of first polymer fibers.