Layered Elevator Belt Tension Member for Sheave Bending Relief
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Solution Overview
Problem
Elevator systems using unidirectional composite load bearing tension members face high bending stress due to their construction, which can lead to inefficiencies when wrapped around traction sheaves, particularly in high-rise systems.
Innovation Solution
A load bearing tension member for elevator systems comprising a plurality of fibers such as carbon, glass, aramid, or polymer fibers embedded in a polymeric matrix, enclosed in an elastomeric jacket, arranged to reduce bending resistance and optimized for use with smaller sheave diameters, enhancing traction and durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If unidirectional composite construction is used for load bearing tension members, then light weight and high strength are achieved, but high bending stiffness results which produces substantial bending stress when wrapped around traction sheave
Solution Approach 1:
The tension member is segmented into multiple individual strands rather than a single unidirectional composite. Each strand contains fibers embedded in a polymeric matrix, and the strands are arranged in a specific pattern (e.g., hexagonal or circular) around a central axis. This segmentation allows each strand to independently accommodate bending stresses while maintaining overall load-bearing capacity.
Solution Approach 2:
The invention uses composite materials at multiple levels: fibers embedded in polymeric matrix within each strand, and strands arranged in a composite configuration around a central core. This multi-level composite structure provides both the strength of unidirectional composites and the flexibility needed to reduce bending stress when wrapped around traction sheaves.
2Weight of moving object
If unidirectional composite construction is used for load bearing tension members, then light weight is achieved, but high bending stiffness results which produces substantial bending stress
Solution Approach 1:
The tension member is divided into multiple flexible strands that can independently bend and conform to the traction sheave surface. This segmentation maintains the lightweight advantage of composite materials while eliminating the high bending stiffness problem of unidirectional construction.
Solution Approach 2:
The invention transitions from a unidirectional linear structure to a three-dimensional stranded configuration. The strands are arranged in radial patterns around a central axis, creating a dimensional change that provides flexibility in the bending direction while maintaining tensile strength along the length of the tension member.
3Stability of the object's composition
If high bending stiffness is present in load bearing tension members, then structural integrity is maintained, but substantial bending stress is produced when wrapped around traction sheave
Solution Approach 1:
The tension member is segmented into multiple strands that can independently flex and conform to the sheave surface, reducing bending stress while the collective arrangement of all strands maintains overall structural integrity through their coordinated configuration.
Solution Approach 2:
The invention changes the structural parameters from a solid unidirectional composite to a stranded configuration with specific geometric arrangements (e.g., hexagonal or circular patterns). This parameter change reduces the effective bending stiffness while maintaining tensile strength and structural integrity through the distributed strand architecture.
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 reduces bending stress and allows for more compact elevator systems while maintaining strength and durability, improving the operational efficiency and space utilization of high-rise elevator systems.
Implementation Method 1
a plurality of fibers such as carbon, glass, aramid, or polymer fibers embedded in a polymeric matrix, enclosed in an elastomeric jacket
Data Source
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AI summary
A load bearing tension member (16) for an elevator system (10) includes a plurality of tension elements (24) arrayed across a tension member (16) width. The tension elements (24) are offset from a tension member central axis (42), the central axis (42) bisecting a tension member (16) thickness and extending across the tension member (16) width. The tension elements (24) include a plurality of fibers (38) extending along a length of the tension element (24), and a matrix material (40) in which the plurality of fibers (38) are embedded. A jacket (28) at least partially encapsulates the plurality of tension elements (24).