Elevator Traction Members With LCP Fibers for Lightweight Flexibility
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Solution Overview
Problem
Existing load-bearing members for elevators, such as steel cords, are too heavy for high-rise applications, while carbon fiber belts require a rigid thermoset matrix that reduces flexibility.
Innovation Solution
A lifting member composed of liquid crystal polymer fibers coated with specific polymers to enhance adhesion and flexibility, incorporating an elastomeric matrix for improved strength-to-weight ratio and durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If steel cords are used as load-bearing members, then strength is sufficient, but weight becomes too heavy for high-rise elevator use
Solution Approach 1:
The patent uses liquid crystal polymer (LCP) fibers as the load-bearing component instead of traditional steel cords. LCP is a composite material that combines the high strength characteristics of crystalline polymer structures with the flexibility and lightweight properties of synthetic fibers, achieving both reduced weight and sufficient tensile strength for high-rise elevator applications.
Solution Approach 2:
The patent changes the material parameter from metal (steel) to advanced polymer (liquid crystal polymer), fundamentally altering the density and strength-to-weight ratio. This parameter change enables the lifting member to be significantly lighter while maintaining the required load-bearing capacity through the unique molecular structure of LCP fibers.
2Weight of moving object
If carbon fiber belts are used to reduce weight, then strength to weight ratio improves, but flexibility is reduced due to rigid thermoset matrix
Solution Approach 1:
The patent changes the matrix material parameter from rigid thermoset to flexible thermoplastic polymer. This parameter change allows the LCP fibers to be embedded in a flexible matrix that maintains the lightweight advantage while restoring the necessary flexibility for the lifting member to bend and flex during elevator operation, unlike rigid thermoset matrices.
Solution Approach 2:
The patent creates a composite structure where liquid crystal polymer fibers are embedded in a thermoplastic matrix. This composite combines the high strength-to-weight ratio of LCP fibers with the flexibility and processability of thermoplastic materials, achieving both lightweight construction and operational flexibility simultaneously.
3Ease of operation
If liquid crystal polymer fibers are used, then flexibility is improved, but adhesion and durability require enhancement through coating
Solution Approach 1:
The patent introduces polymer coatings as an intermediary layer between the LCP fibers and the external environment. These coatings serve as a mediator that enhances adhesion between fibers and matrix material, improves surface durability, and protects the flexible LCP fibers from environmental degradation, thereby maintaining both flexibility and reliability.
Solution Approach 2:
The patent creates a multi-layer composite structure with coated LCP fibers. The polymer coatings form a protective composite layer that enhances the inherent properties of LCP fibers, improving interfacial adhesion and overall durability while preserving the flexibility characteristics of the underlying fiber structure.
Data Source
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AI summary
A lifting member for an elevator system is disclosed, including a rope formed from a plurality of strands comprising liquid crystal polymer fibers, with the strands extending along a length of the lifting member. A first polymer coating is disposed on outer surfaces of the fibers or on outer surfaces of the strands. A second polymer coating disposed over the first polymer coating.