Warp-Knitted Self-Closing Sleeve to Suppress Thermo-Forming Loops
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Solution Overview
Problem
Protective sleeves for elongate members, such as cables, in harsh environments like the automotive, marine, and aeronautic industries face issues with loop formation during thermo-forming, which can lead to elongate member damage and poor closure properties due to mismatched thermal behaviors of yarns and plastic materials.
Innovation Solution
A warp-knitted textile sleeve with monofilament yarns forming laying-in stitches in the same direction, combined with chain or tricot stitches, to create a balanced knitting pattern that suppresses loop formation and maintains a self-closing shape, using specific plastic materials and yarn configurations to ensure stability and closure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If monofilament yarns in plastic materials are used during thermo-forming to provide stiffness and resilient biasing, then the textile maintains tubular shape and returns to shape after manipulation, but loops form on internal and external faces during thermo-forming which can hook and damage elongate members
Solution Approach 1:
The patent changes the thermal parameters of the yarns by selecting materials with specific glass transition temperatures and softening points that are coordinated between different yarn types. The covering yarns are made of plastic materials with glass transition temperatures of -50°C to 100°C and softening points of 150°C to 300°C, while core yarns use materials like PTFE with melting points of 327°C. This parameter coordination prevents differential shrinkage and loop formation during thermo-forming.
Solution Approach 2:
The patent employs composite yarn structures combining different plastic materials with coordinated thermal properties. The textile comprises covering yarns and core yarns made of different plastic materials (e.g., polyamide, polyester, PTFE) selected to have compatible thermal behaviors. This composite approach ensures uniform shrinkage and eliminates loop formation while maintaining the protective tubular structure.
2Ease of manufacture
If yarns with different thermal behaviors are used in the textile, then the textile can be formed into a tubular sleeve structure, but loops develop during thermo-forming due to mismatched shrinkage between different yarn materials
Solution Approach 1:
The patent specifies precise thermal parameter ranges for different yarn materials to ensure coordinated shrinkage behavior. Covering yarns use plastics with glass transition temperatures of -50°C to 100°C and softening points of 150°C to 300°C, while core yarns use materials with melting points of 200°C to 400°C. This parameter control enables successful thermo-forming without loop development.
Solution Approach 2:
The patent applies different plastic materials with specific thermal properties to different regions of the textile structure - covering yarns on the surface and core yarns internally - with each region's material selected to have coordinated thermal behavior. This local material optimization prevents loops while enabling tubular formation.
3Ease of operation
If the sleeve is made elastic to automatically return to tubular shape, then the sleeve can self-close after being opened for insertion, but the resilient biasing force may create excessive tension that damages the protected members
Solution Approach 1:
The patent controls the glass transition temperatures and softening points of the plastic materials to regulate the elastic recovery characteristics. By selecting materials with specific thermal parameters, the resilient biasing force is optimized to provide self-closing action without excessive tension that could damage protected members.
Solution Approach 2:
The patent uses composite yarn structures with core and covering yarns made of different plastic materials having coordinated thermal properties. This composite construction balances the resilient biasing force to achieve self-closing functionality while preventing excessive tension on protected members.
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 effectively reduces loop formation and enhances the closure ability of the sleeve, providing improved protection and durability for elongate members by maintaining a consistent shape and preventing damage from internal or external hooks.
Implementation Method 1
During this thermo-forming step, monofilament yarns in plastic material(s) shrink and form loops on the internal face or external face of the sleeve
Implementation Method 2
The sleeve is heated at a temperature that is generally close to the glass transition temperature or the softening point of said plastic material(s)
Implementation Method 3
The textile is then cooled down still wrapped around said mandrel or still disposed inside the internal volume of said tube
Data Source
AI summary
The present invention concerns an elongate self-closing sleeve for protecting elongated members, said sleeve having internal and external opposite faces. Said sleeve comprises a warp knitted textile 1 having first 2 and second 3 longitudinal opposite free edges biased toward each other in order to define an internal space wherein said elongate members could be placed therein. Said warp knitted textile 1 comprises a first monofilament yarn 4 and a second monofilament yarn 5 both forming laying-in stitches extending in the same direction between said free edges on at least two wales 6 and a third yarn 12 forming chain stitches or tricot stitches, said first 4 and second 5 yarns being in plastic material(s).