Woven Elevator Load Bearing Member Traction Surface

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Solution Overview

Problem

Elevator systems face challenges in achieving desired traction between belt and traction sheave, with existing solutions like roughened surfaces or steel wire fabrics not fully addressing the need for efficient friction characteristics.

Innovation Solution

An elongated elevator load bearing member comprising metal tension elements woven with non-metallic fibers, coated with an elastomer to create a traction surface with a specific exterior texture, enhancing friction and preventing direct contact between tension elements and sheaves.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If a roughened surface is used on the belt to provide friction characteristics, then traction between belt and sheave is improved, but the surface complexity and manufacturing difficulty increase

Engineering Contradiction:
ImprovetractionVSAvoidsurface complexity
Core Design Contradiction:
ForceVSDevice complexity

Solution Approach 1:

The patent applies different surface characteristics to different parts of the belt structure. The exterior surface of the elastomer coating provides the roughened traction surface, while the interior surface remains smooth for contact with tension elements. This local differentiation resolves the contradiction by providing enhanced traction only where needed at the exterior surface without complicating the entire belt structure.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The belt is constructed as a composite structure with elastomer coating over a woven fabric substrate containing tension elements. This composite approach allows the elastomer layer to provide the roughened exterior surface for traction while the fabric core maintains structural integrity, thereby achieving improved traction without excessive surface complexity.

Inventive Principle:
Principle #40Composite materials

2Strength

If steel wires are used for both warp and weft of the fabric, then strength is improved, but friction characteristics and traction are reduced

Engineering Contradiction:
ImprovestrengthVSAvoidfriction
Core Design Contradiction:
StrengthVSForce

Solution Approach 1:

The patent uses a composite fabric structure combining steel wires for warp (to provide strength) with non-metallic fibers for weft (to provide friction). This composite material approach resolves the contradiction by assigning different material properties to different fabric directions: steel wires maintain structural strength while non-metallic fibers enhance surface friction for improved traction.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent differentiates the material properties of warp and weft fibers based on their functional requirements. Steel wires are used specifically for warp where tensile strength is critical, while non-metallic fibers are used for weft where friction and traction characteristics are more important. This local quality differentiation resolves the strength-friction contradiction.

Inventive Principle:
Principle #3Local quality

3Device complexity

If tension elements are directly exposed, then structural simplicity is maintained, but protection and traction characteristics are compromised

Engineering Contradiction:
Improvestructural simplicityVSAvoidprotection
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent uses an elastomer coating as a flexible protective shell that envelops the woven fabric and tension elements. This thin film coating provides protection to the tension elements from environmental damage and wear, while the flexible nature of the elastomer allows it to conform to the belt structure without adding significant complexity. The coating resolves the contradiction by providing necessary protection while maintaining relatively simple structural form.

Inventive Principle:
Principle #30Flexible shells and thin films

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 provides improved traction and protection of tension elements by creating a defined traction surface that ensures efficient movement of the elevator car while maintaining the structural integrity of the load bearing member.

Implementation Method 1

an elastomer coating over the weave fibers, the coating having an exterior surface texture defined at least in part by the weave fibers

Methodology Applied
Scientific EffectAdhesion: Adhesive

Implementation Method 2

achieving a desired amount of traction between the belt and a traction sheave that causes movement of the belt and thus the elevator car

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP2569243B1Woven load bearing member for a traction elevator system and method of making this member
Publication Date: 2015.07.01 OTIS ELEVATOR CO
  • EP2569243B1 patent drawingFigure 1~3
  • EP2569243B1 patent drawingFigure 4~6

AI summary

An exemplary elongated elevator load bearing member of a traction elevator system includes a plurality of tension elements. A plurality of weave fibers transverse to the tension elements are woven with the tension elements. The weave fibers define at least one traction surface of the load bearing member.