Soluble Thread Footwear Stitching Irritation

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Solution Overview

Problem

Traditional nylon or polyester threads used in athletic footwear stitching can irritate the feet when thin socks or no socks are worn, as they are not comfortable for bare feet or thin sock liners.

Innovation Solution

The use of soluble thread, specifically water-soluble or solvent-soluble thread, for stitching in athletic footwear assembly, which dissolves with water or a suitable solvent after the assembly process, eliminating thread irritation and allowing for comfortable wear without socks or thin liners.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If traditional nylon or polyester threads are used for stitching, then the structural integrity and durability of the footwear is maintained, but the stitching causes irritation and discomfort to the wearer's feet when thin socks or no socks are worn

Engineering Contradiction:
Improvethread irritationVSAvoidstitching strength
Core Design Contradiction:
Object-affected harmful factorsVSStrength

Solution Approach 1:

The patent applies parameter changes by transforming the thread material from traditional nylon or polyester to water-soluble or solvent-soluble polymers. This fundamental material parameter change allows the thread to dissolve after serving its structural purpose during manufacturing, thereby eliminating the harmful irritation effect while the thread maintains sufficient strength during the assembly process to ensure proper structural integrity of the footwear

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs the disposable principle by using water-soluble or solvent-soluble threads that are intentionally designed to be temporary. These threads serve their function during manufacturing and assembly, then are deliberately removed through dissolution with water or solvent. This approach eliminates the need for permanent stitching materials that cause irritation, while ensuring the footwear maintains proper structure during the critical assembly phase

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

2Object-affected harmful factors

If soluble thread is used for stitching, then thread irritation is eliminated and comfort is improved, but the manufacturing process becomes more complex due to the additional dissolution step

Engineering Contradiction:
Improvethread irritationVSAvoidmanufacturing process complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent applies the intermediary principle by introducing water or solvent as a mediating substance that facilitates the removal of the stitching thread. Instead of requiring complex mechanical removal systems or additional equipment, the process uses a simple chemical intermediary (water or solvent) that naturally dissolves the water-soluble or solvent-soluble thread, thereby eliminating thread irritation while adding minimal complexity to the manufacturing process

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces the mechanical system of thread removal (which would require cutting, pulling, or specialized equipment) with a chemical dissolution process. By using water-soluble or solvent-soluble threads, the removal mechanism shifts from mechanical force to chemical interaction, simplifying the overall manufacturing process while effectively eliminating thread irritation and improving wearer comfort

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Adaptability or versatility

If soluble thread is used for stitching, then the footwear can be worn without socks or with thin liners, but the thread may dissolve prematurely during the assembly process affecting structural integrity

Engineering Contradiction:
Improvewearability without socksVSAvoidthread durability during assembly
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent applies local quality by ensuring that the water-soluble or solvent-soluble thread maintains its strength and solubility characteristics specifically suited for each stage of the manufacturing process. The thread is engineered to resist dissolution during the assembly phase when structural integrity is needed, while being readily soluble under controlled conditions (such as during a dedicated dissolution step or when exposed to water/solvent after assembly), thereby enabling wearability without socks while preventing premature dissolution

Inventive Principle:
Principle #3Local quality

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 use of soluble thread ensures a thread-free sock surface, enhancing comfort and reducing irritation while maintaining the structural integrity and durability of the footwear, allowing for lightweight and flexible designs.

Implementation Method 1

the soluble thread is dissolved with water or other appropriate solvent

Methodology Applied
Scientific EffectDissolution: Solvation

Data Source

PatentEP2330938B1Soluble thread in the manufacture of footwear
Publication Date: 2012.03.28 NIKE INTERNATIONAL LTD
  • EP2330938B1 patent drawingFigure 1~2
  • EP2330938B1 patent drawingFigure 3~4
  • EP2330938B1 patent drawingFigure 5a~5b

AI summary

Aspects of the invention relate to the use of soluble thread in the preparation of footwear, in particular athletic footwear. After preparing aspects of the footwear, the soluble thread is dissolved.