Textile Stranded Rope Sheath Structure for Twist-Stable Winding

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Solution Overview

Problem

Textile stranded ropes suffer from lower torsional stiffness, forced twisting, reduced bending fatigue strength, and poor winding capability due to relative movements between strands and sheath layers, leading to delamination and reduced service life.

Innovation Solution

A textile stranded rope design featuring a core and strands with a tubular covering that allows individual strands of the outer layer to move freely, combined with a stabilizing layer and a low-friction sheath to enhance torsional stiffness and prevent twisting, using materials like polyamide and reinforcing fibers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If strands are allowed to move relative to each other to compensate for inherent movements, then the rope achieves better flexibility and adaptability, but torsional stiffness decreases and forced twisting increases

Engineering Contradiction:

Improvestrand movement capabilityVSAvoidtorsional stiffness

Core Design Contradiction:

Adaptability or versatilityVSStability of the object's composition

Solution Approach 1:

The outer strand layer is segmented into individual strands, each enclosed in its own tubular covering. This segmentation allows each strand to move independently within its covering while maintaining overall rope integrity, resolving the contradiction between strand movement capability and torsional stiffness.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Tubular coverings are introduced as intermediary elements between the strands and the external environment. These coverings permit strand movement while providing guidance and preventing uncontrolled displacement, thus maintaining torsional stiffness while allowing necessary adaptability.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If a plastic sheath is used to enclose outer strands, then the rope achieves better protection and reduced friction, but strand movement is restricted and delamination occurs

Engineering Contradiction:

Improvefriction and wear protectionVSAvoidstrand movement freedom

Core Design Contradiction:

Object-affected harmful factorsVSReliability

Solution Approach 1:

Tubular coverings made of flexible materials are used to enclose individual strands. These coverings provide protection against friction and wear while their flexible nature and sufficient length allow strands to move freely within them, preventing delamination and maintaining reliability.

Inventive Principle:

Principle #30Flexible shells and thin films

3Stability of the object's composition

If the lay length factor is increased to reduce relative movements, then the rope achieves better stability, but service life is reduced due to lower flexibility

Engineering Contradiction:

Improverelative movement controlVSAvoidservice life

Core Design Contradiction:

Stability of the object's compositionVSDuration of action of moving object

Solution Approach 1:

The design optimizes the lay length factor within a specific range (6-10) and uses tubular coverings with carefully selected lengths (0.5-2 times the rope diameter). These parameter changes allow the rope to maintain stability while preserving flexibility and extending service life through reduced stress concentrations.

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

The design improves torsional stiffness, rotational stability, and bending fatigue strength while reducing twisting and wear, enhancing the rope's operational performance and service life.

Implementation Method 1

Frictional contact (high coefficient of friction between the sheath and strand) and/or material contact (firm bond between sheath and strand) only allows strand movement due to the elasticity of the sheath material

Methodology Applied

Scientific EffectFriction: Friction

Implementation Method 2

The intermediate layer accommodates relative movement of the strands through elastic deformation

Methodology Applied

Scientific EffectElasticity: Elasticity

Data Source

PatentEP4653609A1Stranded textile cord

Publication Date: 2025.11.26 TROWIS GMBH

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AI summary

The invention relates to the technical field of conveyor technology and concerns a textile stranded rope in which individual or all strands of the outer strand layer have a sheath in which the strands can move freely along their lay direction. The object of the present invention is to provide a textile stranded rope that is characterized by improved torsional stiffness with reduced forced twisting, improved flexural fatigue strength, and improved winding properties. This object is achieved by a textile stranded rope comprising a core and at least one strand layer with strands, wherein the core and the strands are made of a textile material and/or a plastic. The at least one strand layer is formed from several textile strands, wherein at least individual strands of an outer strand layer have a tubular sheath.The textile stranded rope can be used, for example, as a load-bearing element in multi-layered wound drum winches.