Conductive ETFE Cord Reel Cable for EMI Shielding and Flexibility
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Solution Overview
Problem
Existing cord reel assemblies face challenges in providing a flexible, durable, and EMI/crosstalk-resistant solution, as conventional shielding methods tend to fray or limit flexibility, and encapsulation techniques lack the necessary strength and resistance for multiconductor cables.
Innovation Solution
A cable design featuring a bundle of conductors with a grounded drain wire contacting a conductive polymeric ETFE layer, which is vacuum sealed but not fully encapsulating the ends, combined with a Teflon coating and helical configuration to minimize crosstalk and whiskering, while allowing for connection to other wires.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional copper shielding layers are used to prevent EMI and crosstalk, then EMI protection is improved, but the cable becomes less flexible and more prone to fraying over time
Solution Approach 1:
The patent changes the material parameter from traditional copper shielding to a polymeric coating with conductive particles (such as carbon black or metal oxides). This parameter change maintains the EMI shielding functionality while fundamentally improving flexibility and eliminating fraying issues associated with copper wires. The polymeric matrix allows the coating to stretch and bend without the rigidity and fraying problems of metal wire meshes.
Solution Approach 2:
The patent employs a composite material structure where conductive particles are dispersed within a polymeric coating matrix. This composite approach combines the EMI shielding properties of conductive materials with the flexibility and durability of polymers. The composite structure allows the coating to maintain electrical conductivity for EMI protection while exhibiting the mechanical flexibility and resistance to fraying characteristic of polymeric materials.
2Strength
If multiple layers are added outside the bundle of conductors to improve durability, then durability is improved, but the flexibility of the resulting cable is limited
Solution Approach 1:
The patent merges the EMI shielding function and the protective jacket function into a single integrated polymeric coating layer. Instead of adding separate copper shielding layers and multiple protective jackets, the conductive particles are incorporated directly into the polymeric coating, creating a multi-functional single layer that provides both EMI protection and mechanical durability while maintaining flexibility.
Solution Approach 2:
The patent uses a thin polymeric coating layer with embedded conductive particles as both the protective shell and EMI shielding layer. This flexible film approach replaces traditional rigid or semi-rigid multiple-layer constructions, allowing the cable to maintain high flexibility while providing adequate protection and EMI shielding through the conductive polymer composite structure.
3Ease of manufacture
If encapsulation techniques are used for wire assemblies, then manufacturing is simplified, but the resulting material lacks the necessary strength, flexibility, and flame resistance for cord reel applications
Solution Approach 1:
The patent changes the material composition parameter by selecting specific flame-retardant polymers (such as polyolefins or polymers with halogen-free flame retardants) and optimizing the concentration and type of conductive particles. This parameter optimization ensures the coating meets flame resistance and smoke toxicity requirements while maintaining flexibility and conducting EMI to the drain wire, all within a single extrusion process that simplifies manufacturing.
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 provides superior EMI and crosstalk resistance, maintains flexibility, and meets requirements for flame, smoke, and toxicity resistance, while preventing fraying and ensuring effective EMI shielding in cord reel assemblies.
Implementation Method 1
an outer jacket of a conductive polymeric material and drain or drain wire amongst the conductors which contacts the outer jacket in order to reduce or eliminate electromagnetic interference into the cable
Data Source
AI summary
A cord reel cable including a polymeric sheath with a conductive EMI drain and a method of manufacture therefor. The cord reel includes a cable comprising power and data conductors, as wells as a single drain wire which is grounded to a cord reel housing or spool or the like. The drain wire contacts an outer ETFE layer surrounding the cable in order to provide EMI shielding to the cable.