Segmented Undersole for Hallux Valgus Support

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Solution Overview

Problem

Conventional shoes are not suitable for supporting walking in individuals with hallux valgus, hallux rigidus, or hallux varus due to their design, which exacerbates foot misalignment and joint issues, and existing insoles and orthopedic solutions are either ineffective or excessively costly for mass production.

Innovation Solution

A dimensionally stable undersole with a PU cushioning layer, designed to be integrated into the shoe structure, providing relief to the toe and ball areas and adaptable to different foot shapes, with varying bending stiffness in its sub-areas to reduce rolling behavior at the big toe joint.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If conventional shoes with standard sole construction are used, then manufacturing is simple and cost-effective, but they exacerbate foot misalignment and joint issues in hallux valgus patients

Engineering Contradiction:

Improvemanufacturing simplicityVSAvoidfoot misalignment exacerbation

Core Design Contradiction:

Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The insole divides the forefoot area into two laterally adjacent sub-areas with different flexural rigidities: the inner sub-area has higher flexural rigidity to support the big toe joint and prevent valgus deformation, while the outer sub-area has lower flexural rigidity to maintain natural foot flexibility. This local differentiation of mechanical properties directly addresses the contradiction by providing targeted support where needed without compromising overall manufacturing simplicity.

Inventive Principle:

Principle #3Local quality

2Object-affected harmful factors

If custom-made orthopedic insoles are produced, then foot support and misalignment correction are improved, but manufacturing costs become excessively high for mass production

Engineering Contradiction:

Improvejoint damage preventionVSAvoidmanufacturing cost

Core Design Contradiction:

Object-affected harmful factorsVSEase of manufacture

Solution Approach 1:

The insole is segmented into functionally distinct sub-areas (inner and outer forefoot regions) with different flexural rigidities, allowing standardized mass production of modular components that can be assembled into custom-fitting insoles. This segmentation enables the use of automated molding techniques and pre-fabricated parts, significantly reducing manufacturing costs compared to fully custom-made insoles while maintaining the orthopedic benefits of personalized foot support.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention changes the material parameters (flexural rigidity, hardness) of different insole regions to achieve the desired mechanical behavior. By using materials with varying degrees of rigidity in specific zones, the insole provides customized orthopedic support without requiring expensive hand-crafted construction, thus making mass production of therapeutic insoles economically feasible.

Inventive Principle:

Principle #35Parameter changes

3Ease of operation

If the outsole has different flexural rigidities in the forefoot area to create rolling behavior, then walking comfort is improved, but the valgus position in the big toe joint is exacerbated

Engineering Contradiction:

Improvewalking comfortVSAvoidbig toe joint valgus position

Core Design Contradiction:

Ease of operationVSObject-affected harmful factors

Solution Approach 1:

Instead of allowing the natural rolling motion of the foot to proceed unchecked (which exacerbates hallux valgus), the insole inverts the approach by providing targeted resistance in the inner forefoot area through higher flexural rigidity. This inverted approach—providing support where the problem occurs rather than allowing natural motion—directly counteracts the valgus deformation while maintaining overall walking comfort through the softer outer region.

Inventive Principle:

Principle #13The other way round (Inversion)

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 undersole effectively stabilizes the shoe bottom, reducing the progression of hallux-related misalignments and associated pain by modifying the gait pattern and distributing pressure more evenly, thus improving comfort and reducing the risk of further joint damage.

Implementation Method 1

distributing pressure more evenly

Methodology Applied

Scientific EffectPressure distribution:

Implementation Method 2

PU cushioning layer

Methodology Applied

Scientific EffectCushioning:

Implementation Method 3

varying bending stiffness in its sub-areas to reduce rolling behavior at the big toe joint

Methodology Applied

Scientific EffectBending stiffness variation:

Implementation Method 4

different flexural rigidities in the longitudinal direction

Methodology Applied

Scientific EffectFlexural rigidity differential:

Data Source

PatentEP4360492A1Base plate for shoe sole

Publication Date: 2024.05.01 HELBIG ACHIM

Figure 1
Figure 2a~2c

AI summary

The present invention relates generally to the characteristic features of footwear with a health-promoting device in the form of an insole. The insole provides support for the prevention and treatment of hallux valgus (bunion). By positioning the insole under the foot, particularly in the sole of the shoe, a positive effect on the big toe joint is achieved. This effect influences the rolling motion of the big toe joint, which helps to reduce or prevent pain and inflammation in the toe joint. Further damage and deformities of the bunion are reduced by the inventive insole, and the wearing comfort of the footwear is increased.