Four-Layer Knitted Fabric with Hidden Conductive Heating Layer

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Solution Overview

Problem

Existing heat-generating textile products often expose electrically conductive yarns, leading to skin burns and discomfort, and rely on specialized batteries, reducing user convenience.

Innovation Solution

A weft knitted fabric with a four-layer structure where the electrically conductive layer is hidden beneath non-conductive layers, forming uniformly distributed protrusions that generate heat when energized, using a general-purpose power supply via a three-port USB connector with adjustable power control.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If electrically conductive yarn is used to generate heat in the textile product, then heat generation function is achieved, but the conductive yarn is exposed to the fabric surface causing skin burns and discomfort

Engineering Contradiction:
Improveheat generationVSAvoidskin burns
Core Design Contradiction:
TemperatureVSObject-affected harmful factors

Solution Approach 1:

The conductive yarn is nested within multiple fabric layers (first, second, and third layers) rather than being exposed on the surface. The heating element is embedded inside the textile structure like a nested doll, with non-conductive outer layers providing protection while the conductive inner layer generates heat, thus preventing skin contact and burns.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

Non-conductive fabric layers serve as intermediary barriers between the conductive heating yarn and the user's skin. These intermediary layers transfer the heat function while blocking direct contact with the conductive element, preventing harmful effects while maintaining the heating function.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Temperature

If specialized batteries are used in heat-generating textile products, then heat generation function is achieved, but user convenience and comfort are reduced due to non-general-purpose requirements

Engineering Contradiction:
Improveheat generationVSAvoiduser convenience
Core Design Contradiction:
TemperatureVSEase of operation

Solution Approach 1:

The textile product is designed to work with universal general-purpose batteries rather than requiring specialized battery types. This universality allows users to use commonly available batteries, greatly improving convenience and comfort while maintaining the heat generation function through the multi-layer protective structure.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 fabric provides a comfortable, heat-generating zone without direct exposure to conductive yarns and can use standard batteries, offering improved user safety and convenience with adjustable heat settings.

Implementation Method 1

the second fabric layer is electrically conductive such that when the second fabric layer is electrically energized, air trapped inside the protrusions is heated up, causing the knitted fabric to generate heat

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Data Source

PatentEP3561163B1Knitted fabric having heat generating function and manufacturing method therefor
Publication Date: 2022.08.24 KNITWARM LTD
  • EP3561163B1 patent drawingFigure 1
  • EP3561163B1 patent drawingFigure 2~3
  • EP3561163B1 patent drawingFigure 4

AI summary

A knitted fabric having a heat generating function has a four-layer structure and can be knitted by a flat knitting machine. Knit stitching is used to knit first and second layers such that the second layer is fully covered under the first layer. Tuck stitching is used to knit the third layer such that one stitch is made to the third layer per a preset number of stitches made to each of first and second layers. Knit stitching is used to knit the fourth layer. After knitting, the fabric is soaked with water and spin-dried to form protrusions, spatially distributed as a centered rectangular lattice, on fabric surface. The second layer is electrically conductive for generating heat and is hidden inside the fabric. This layer is not easily hooked by a user during use and cleaning. The fabric is elastic and soft, and provides a comfortable feeling to the user.