Overlapping Instep Footwear Structure for Swollen Feet

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Solution Overview

Problem

Existing footwear designs for individuals with swollen feet due to edema or lymphedema are difficult to wear and require cumbersome fastening mechanisms, often leading to discomfort and hindrance during walking, especially for those with severe swelling or impaired mobility.

Innovation Solution

The footwear features a separated inside and outside instep-covering parts with an overlapping range that allows easy foot insertion and walking, fixed to the sole at the toe section, and optionally uses elastic materials for compression, convex portions for lymphatic flow promotion, and a three-layer structure for comfort and support.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the instep section is made separable with hook-and-loop fasteners to accommodate swollen feet, then ease of wearing is improved, but device complexity increases and fastening becomes troublesome

Engineering Contradiction:
Improveease of wearingVSAvoidfastening mechanism complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent removes the complex hook-and-loop fastening mechanism entirely, extracting only the essential function of accommodating swollen feet through a simple separable instep design. The instep section is divided into two independent parts that can be separately positioned without requiring fasteners, thus eliminating the troublesome fastening operation while maintaining the ability to accommodate foot swelling.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The instep section is segmented into an inner instep section and an outer instep section that can be independently positioned. This segmentation allows the shoe to accommodate swollen feet by separating the instep covering parts, eliminating the need for complex fastening mechanisms while maintaining adaptability to different foot conditions.

Inventive Principle:
Principle #1Segmentation

2Adaptability or versatility

If the instep section is made separable to accommodate edema, then adaptability to swollen feet is improved, but reliability of shoe retention during walking deteriorates

Engineering Contradiction:
Improveadaptability to swollen feetVSAvoidshoe retention during walking
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The shoe upper is segmented into separate instep sections that can independently accommodate swollen feet while maintaining overall shoe integrity. The inner and outer instep sections can be positioned separately to fit various foot conditions without compromising the shoe's ability to stay on during walking.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The separable instep design applies local quality changes only where needed (at the instep section) to accommodate swollen feet, while the rest of the shoe structure maintains its normal integrity and retention properties. This localized approach ensures adaptability to edema without sacrificing overall shoe reliability during walking.

Inventive Principle:
Principle #3Local quality

3Reliability

If the tongue or fastening pieces are joined to the instep section, then shoe retention during walking is improved, but ease of wearing deteriorates due to bending forward requirement

Engineering Contradiction:
Improveshoe retention during walkingVSAvoidease of fastening operation
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The patent extracts and removes the troublesome fastening operation entirely by eliminating the need to join tongue or fastening pieces to the instep section. The separable instep design achieves shoe retention through the configuration of the inner and outer instep sections themselves, without requiring additional fastening components or bending forward operations.

Inventive Principle:
Principle #2Taking out (Extraction)

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

Enables easy wearing and smooth walking by eliminating the need for fastening, providing compression for lymphatic health, and reducing discomfort through elastic support and convex stimulation, suitable for individuals with edema or lymphedema.

Implementation Method 1

the upper is formed using an elastic material, and at least one of the toe section and a heel section is capable of applying a predetermined compression

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

convex portions for lymphatic flow promotion

Methodology Applied
Scientific EffectMechanical stimulation: Vibration

Data Source

PatentEP4696181A1footwear
Publication Date: 2026.02.18 MITSUI MEDICAL JAPAN CO LTD
  • EP4696181A1 patent drawingFigure 1
  • EP4696181A1 patent drawingFigure 2
  • EP4696181A1 patent drawingFigure 3(a)~3(b)

AI summary

Provided is footwear that can be easily worn even if a foot is swollen due to lymphedema or the like, and can also be worn when the foot is in a normal condition. An upper 10 is composed of an inside instep-covering part 110 and an outside instep-covering part 120 that are separated, and in its dorsum-corresponding section 4 from a toe section 2 to a foot insertion opening 3, it has an overlapping range A where the inside instep-covering part 110 and the outside instep-covering part 120 overlap with each other. The inside instep-covering part 110 and the outside instep-covering part 120 are not joined to each other in the overlapping range A. Therefore, when the foot is inserted through the foot insertion opening 3, the inside instep-covering part 110 and the outside instep-covering part 120 can each be significantly displaced outward, allowing the footwear to be easily worn even if the foot has edema.