Warp-Knitted Self-Closing Sleeve to Prevent Thermo-Forming Loops
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Solution Overview
Problem
Existing elongate self-closing sleeves for protecting cables and optical fibers in harsh environments, such as those in the aeronautic, marine, railway, and automotive industries, face issues with loop formation during the thermo-forming process, which can lead to elongate member damage and poor closure efficiency due to thermal behavior mismatches between yarns and plastic materials.
Innovation Solution
A warp-knitted textile sleeve with two monofilament yarns forming laying-in stitches in the same direction, combined with chain or tricot stitches, to provide balanced biasing force and prevent loop formation, using plastic materials like polyamide and fluoropolymers, and optionally additional yarns for enhanced resiliency and stiffness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If monofilament yarns in plastic materials are used to provide stiffness and strong resilient biasing, then the sleeve maintains tubular shape and provides self-closing function, but loops form on the internal or external face during thermo-forming, causing unsightly appearance and potential damage to elongate members
Solution Approach 1:
The patent changes the physical state and thermal parameters of the plastic material during processing. By controlling the thermo-forming temperature to be at or above the glass transition temperature of the plastic material, the yarns become more pliable and less prone to forming loops. The controlled cooling process then sets the desired tubular shape without excessive shrinkage that would cause loop formation.
Solution Approach 2:
The patent utilizes thermal expansion and contraction principles during the thermo-forming process. The plastic material is heated to expand and become formable, then cooled to contract and maintain the tubular shape. This controlled thermal cycling allows the sleeve to achieve the desired shape memory effect without excessive shrinkage that would cause loops on the surface.
2Stability of the object's composition
If the textile is thermo-formed to impart shape memory and elastic behavior, then the sleeve automatically returns to tubular shape and provides self-closing function, but the thermal behavior mismatch between yarns and plastic materials causes excessive loop development
Solution Approach 1:
The patent carefully controls the thermal parameters during thermo-forming, including temperature, heating time, and cooling rate. By optimizing these parameters, the plastic material achieves the desired shape memory effect while minimizing differential shrinkage between the yarns and the plastic matrix, thereby reducing loop formation.
Solution Approach 2:
The patent uses composite materials consisting of plastic material with embedded monofilament yarns. The plastic matrix and yarns work together to provide both shape memory and structural integrity. The composite structure allows the plastic to dominate the thermal behavior, reducing the mismatch between yarn and substrate thermal responses during thermo-forming.
3Adaptability or versatility
If the sleeve is made with yarns of different diameters or materials to provide diverse functions, then the sleeve can be optimized for specific applications, but thermal behavior differences cause more pronounced loop formation
Solution Approach 1:
The patent controls the thermo-forming parameters to account for the thermal properties of different yarn materials. By adjusting the heating temperature and duration based on the specific yarn composition, the patent minimizes differential shrinkage between various yarn types, reducing loop formation while maintaining the functional benefits of diverse yarn selections.
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 suppresses loop formation and maintains a stable tubular shape, ensuring efficient closure and protection of elongate members while maintaining mechanical and thermal stability, even when used with diverse thermal behavior yarns, and provides improved abrasion resistance and sound dampening properties.
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 textile is then cooled down still wrapped around said mandrel or still disposed inside the internal volume of said tube. This thermo-forming step may be performed only if the sleeve comprises a monofilament yarn in a plastic material. This thermo-forming step imparts a shape memory or elastic memory to the textile
Data Source
Figure 1
Figure 2A
Figure 2B
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).