Cable Sheath Spiral Orientation for Tear Resistance
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Solution Overview
Problem
Cables with conventional extrusion processes lack sufficient mechanical strength, particularly against tearing, and often feature a flow seam that runs along the longitudinal axis, which can be a weak point.
Innovation Solution
A cable with a single-layer or multi-layer sheath is designed where the polymer mixtures forming the sheath are oriented at an angle to the longitudinal center plane, creating a spiral arrangement that enhances the mechanical strength by interlocking the layers, and an extruder nozzle with guide elements is used to shape the polymer mixtures, ensuring the sheath has alternating radial sections between a minimum and maximum radius, thereby increasing the sheath's resistance to tearing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional extrusion process is used to produce cable sheath, then the manufacturing process is simple, but the mechanical strength against tearing is insufficient
Solution Approach 1:
The patent applies curvature by forming the sheath in a spiral configuration around the cable core rather than as a straight longitudinal layer. This spiral arrangement creates interlocking geometry that significantly improves tear resistance while maintaining manufacturing feasibility through modified extrusion processes
Solution Approach 2:
The invention transitions from a two-dimensional planar sheath layout to a three-dimensional spiral configuration. By adding the dimensional aspect of wrapping angles and multiple layers, the sheath gains enhanced mechanical strength without proportionally increasing manufacturing complexity
2Strength
If flow seam runs along the longitudinal axis of the cable, then the extrusion process is straightforward, but the flow seam becomes a weak point reducing mechanical strength
Solution Approach 1:
The flow seam is redirected from a straight longitudinal path to a spiral configuration that follows the sheath's wrap pattern. This curved arrangement distributes stress more evenly and eliminates the weak longitudinal seam by integrating it into the spiral reinforcement structure
Solution Approach 2:
The patent introduces asymmetric positioning of the flow seam relative to the cable axis through the spiral arrangement. Instead of symmetric alignment with the longitudinal axis, the flow seam follows an asymmetric spiral path that enhances strength by distributing potential failure points around the circumference
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 angled orientation of the sheath layers results in a higher mechanical strength against tearing, with the spiral arrangement and interlocking sections providing enhanced durability compared to conventional cables, while maintaining a similar overall thickness.
Implementation Method 1
the sheath, which is single-layer or multi-layer, preferably two-layer, has a higher resistance produced by the extrusion process than the sheath of a cable which is produced from the same material using a conventional extrusion process
Data Source
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AI summary
The invention relates to a cable with a sheath that is single-layered or multi-layered, in particular two-layered consisting of an outer layer and an inner layer, wherein the polymer mixtures of the sheath and/or the flow seam in the sheath are arranged directed at an angle to the longitudinal median plane of the cable, which extends from the longitudinal axis of the cable.