Elevator Rope Inner Layer Strand Design

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Solution Overview

Problem

Conventional elevator ropes face issues with fiber core melting and breakage due to heat, structural gaps leading to deformation and diameter reduction, increased contact pressure causing abrasion and wire breakages, and insufficient cross-sectional area for rope grease.

Innovation Solution

An elevator rope design featuring a fiber core with a plurality of steel inner layer strands twisted around it, coated with a resin layer, and additional steel outer layer strands, where the inner layer strands have a smaller diameter and greater number than the outer layer strands, providing protection and maintaining cross-sectional area.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a core rope is constituted by fibers and coated with a resin coating body, then the core rope provides flexibility and rope grease impregnation, but the fibers may melt and break due to heat from the molding machine

Engineering Contradiction:
Improvecoating processVSAvoidfiber core integrity
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

An inner layer strand acts as an intermediary protective barrier between the fiber core and the resin coating body. This inner layer strand shields the fiber core from direct contact with hot resin during the coating process, preventing fiber melting and breakage while allowing the resin coating to be applied successfully.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The inner layer strand is placed around the fiber core before the resin coating process to provide advance protection. This pre-positioned protective layer cushions the fiber core against thermal damage from the molding machine, ensuring fiber integrity before the harmful heat exposure occurs.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

2Device complexity

If the core rope is not tightened except during twisting, then the structure remains simple, but structural gaps remain causing deformation and diameter reduction due to extensive use

Engineering Contradiction:
Improvecore rope structureVSAvoidcore rope shape
Core Design Contradiction:
Device complexityVSStability of the object's composition

Solution Approach 1:

The rope structure is segmented into multiple functional layers: an inner layer strand directly surrounding the fiber core, and an outer layer strand surrounding the inner layer. This segmentation allows the inner layer to specifically address core tightening and shape stability, while the outer layer provides additional structural support and protection.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The rope structure employs a nested configuration where the inner layer strand is positioned inside the outer layer strand, both surrounding the fiber core. This nested arrangement enables the inner layer to tightly conform to and stabilize the fiber core, preventing deformation and diameter reduction while maintaining overall structural integrity.

Inventive Principle:
Principle #7Nested doll (Nesting)

3Quantity of substance

If the cross-sectional area of the fiber core is increased to ensure sufficient rope grease content, then rope grease capacity improves, but the overall rope diameter increases

Engineering Contradiction:
Improverope grease contentVSAvoidrope diameter
Core Design Contradiction:
Quantity of substanceVSLength of stationary object

Solution Approach 1:

The inner layer strand has a smaller diameter than the outer layer strand, creating a localized structure that maximizes the cross-sectional area available for rope grease impregnation within the fiber core. This local optimization ensures sufficient grease capacity without unnecessarily increasing the overall rope diameter.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

By changing the diameter parameter of the inner layer strand to be smaller than the outer layer strand, the design optimizes the space available for rope grease storage in the fiber core. This parameter adjustment ensures adequate grease content while controlling the overall rope dimensions.

Inventive Principle:
Principle #35Parameter changes

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

This design enhances the service life of elevator ropes by preventing fiber core breakage, reducing deformation, and ensuring sufficient rope grease content, while minimizing unit mass and manufacturing complexity.

Implementation Method 1

a plurality of steel inner layer strands that are twisted together on an outer circumference of the fiber core

Methodology Applied
Scientific EffectTwisting:

Implementation Method 2

a resin inner layer rope coating body that is coated onto an outer circumference of the inner layer strands

Methodology Applied
Scientific EffectCoating: Coatings

Implementation Method 3

a plurality of steel outer layer strands that are twisted together on an outer circumference of the inner layer rope

Methodology Applied
Scientific EffectTwisting:

Data Source

PatentEP2808286B1Elevator rope
Publication Date: 2016.03.23 MITSUBISHI ELECTRIC CORP
  • EP2808286B1 patent drawingFigure 1
  • EP2808286B1 patent drawingFigure 2
  • EP2808286B1 patent drawingFigure 3

AI summary

In an elevator rope, a plurality of steel outer layer strands are twisted together on an outer circumference of an inner layer rope. The inner layer rope has: a fiber core; a plurality of steel inner layer strands that are twisted together directly onto an outer circumference of the fiber core; and a resin inner layer rope coating body that is coated onto the outer circumference. A diameter of the inner layer strands is smaller than a diameter of the outer layer strands. The inner layer strands are greater in number than the outer layer strands.