Elevator Belt Tension Member Composition for Smaller Sheaves
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Solution Overview
Problem
Elevator systems using carbon fiber composite tension members require large diameter sheaves due to limited flexibility, which can lead to increased size and weight, compromising efficiency and operational smoothness.
Innovation Solution
A belt system with tension members comprising at least 50% aromatic polyester based fibers, such as liquid crystal polymer, encapsulated in a jacket material like polyurethane or epoxy, allowing for improved flexibility and reduced sheave diameter through the use of a matrix material, enhancing strength-to-weight ratio and operational flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If carbon fiber composite tension members are used, then strength to weight characteristics are improved, but flexibility is limited requiring large diameter sheaves
Solution Approach 1:
The patent uses composite materials consisting of aromatic polyester fibers (such as liquid crystal polymer) combined with other reinforcement fibers like carbon fibers, glass fibers, or aramid fibers. This composite structure maintains the high strength-to-weight ratio while improving flexibility compared to pure carbon fiber composites, thereby resolving the contradiction between weight reduction and flexibility enhancement.
Solution Approach 2:
The patent changes the material parameters by specifying that at least 50% of the load-bearing fibers must be aromatic polyester-based fibers with specific molecular weight and crystallinity characteristics. This parameter change enables the tension member to achieve both lightweight properties and sufficient flexibility for operation with smaller diameter sheaves.
2Strength
If carbon fiber composite tension members are used, then strength is improved, but sheave diameter must be increased
Solution Approach 1:
The patent employs composite materials with aromatic polyester fibers as the primary load-bearing component (at least 50% of total fibers), combined with supplementary reinforcement fibers. This composite configuration achieves the required strength levels while maintaining flexibility that allows the use of smaller diameter sheaves, thus reducing the volume of moving objects in the elevator system.
3Ease of operation
If aromatic polyester fibers are used as load carrying fibers, then flexibility is improved, but manufacturing complexity increases
Solution Approach 1:
The patent specifies a composite fiber composition where aromatic polyester fibers (providing flexibility) constitute at least 50% of the load-bearing fibers, combined with other reinforcement fibers. This defined ratio and composition guide the manufacturing process, making the production of flexible belts more systematic and less complex by establishing clear material specifications and blending ratios.
Data Source
Figure 1
Figure 2~3
AI summary
A belt (16) for an elevator system includes a plurality of tension members (24) arranged along a belt width and extending longitudinally along a length of the belt (16), each tension member (24) including a plurality of load carrying fibers, the plurality of load carrying fibers including a plurality of aromatic polyester based fibers. A jacket material (28) at least partially encapsulates the plurality of tension members (24).