Sole Plate Fiber Alignment for Foot Stability

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Solution Overview

Problem

Sole plates with high flexural rigidity due to multiple fiber layers cause increased loads on the foot during natural running motions and compromise stability, especially when contacting the ground from the outer side.

Innovation Solution

A sole plate with a reinforcement portion made of a composite material containing synthetic resin and fibers, where fibers are aligned in the foot length direction, providing higher flexural rigidity in this direction while maintaining lower rigidity in the foot width direction, thus mitigating ground contact loads and enhancing stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If a plate is formed of a plurality of fiber layers to increase flexural rigidity, then stability is improved, but loads imposed on the foot during ground contact increase

Engineering Contradiction:
ImprovestabilityVSAvoidloads on foot
Core Design Contradiction:
Stability of the object's compositionVSForce

Solution Approach 1:

The plate incorporates a reinforcement portion with specifically oriented fibers (aligned in the foot length direction) rather than uniform fiber distribution throughout the entire plate. This localized reinforcement provides enhanced stability in the longitudinal direction while maintaining flexibility in the transverse direction, thereby reducing excessive loads on the foot during ground contact.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The fiber orientation in the reinforcement portion is asymmetrically arranged with fibers aligned primarily in the foot length direction, creating different mechanical properties in different directions. This asymmetric structure provides higher flexural rigidity longitudinally while maintaining lower rigidity laterally, resolving the contradiction between stability and load reduction.

Inventive Principle:
Principle #4Asymmetry

2Stability of the object's composition

If the plate is arranged lower in the sole, then stability is enhanced, but loads on the foot during ground contact increase

Engineering Contradiction:
ImprovestabilityVSAvoidloads on foot
Core Design Contradiction:
Stability of the object's compositionVSForce

Solution Approach 1:

When the plate is positioned lower in the sole, the reinforcement portion with aligned fibers provides targeted structural support that enhances stability without uniformly increasing rigidity across the entire foot structure. The localized reinforcement allows the plate to function effectively at lower positions while mitigating excessive load transmission to the foot.

Inventive Principle:
Principle #3Local quality

3Stability of the object's composition

If flexural rigidity in the foot length direction is increased, then stability is improved, but shock mitigation during ground contact is reduced

Engineering Contradiction:
ImprovestabilityVSAvoidshock
Core Design Contradiction:
Stability of the object's compositionVSObject-affected harmful factors

Solution Approach 1:

The reinforcement portion is strategically positioned and configured to provide enhanced flexural rigidity specifically in the foot length direction where stability is needed, while the rest of the plate structure maintains sufficient flexibility for shock absorption. This localized approach to rigidity enhancement resolves the contradiction between stability and shock mitigation.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The anisotropic fiber arrangement creates asymmetric mechanical properties with higher rigidity in the longitudinal direction and lower rigidity in the transverse direction. This asymmetry allows the plate to provide stability during propulsion while maintaining shock-absorbing characteristics during impact phases of gait.

Inventive Principle:
Principle #4Asymmetry

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 solution effectively reduces shock and deformation during ground contact while improving stability by ensuring higher flexural rigidity in the foot length direction, at least twice that of the foot width direction, thereby enhancing running efficiency and reducing excessive deformation.

Implementation Method 1

a reinforcement portion composed of a composite material containing a synthetic resin and a plurality of fibers

Methodology Applied
Scientific EffectComposite materials: Composite Materials

Implementation Method 2

the plurality of fibers in the reinforcement portion each have such an orientation property that orientations are aligned in a foot length direction

Methodology Applied
Scientific EffectFiber alignment: Anisotropy

Data Source

PatentEP4166026B1Plate, sole, shoe, and method of manufacturing plate
Publication Date: 2024.05.29 ASICS CORP
  • EP4166026B1 patent drawingFigure 1
  • EP4166026B1 patent drawingFigure 2
  • EP4166026B1 patent drawingFigure 3

AI summary

A plate (300) is used for a sole that forms a part of a shoe. The plate (300) includes a reinforcement portion (310) composed of a composite material containing a synthetic resin and a plurality of fibers. The plurality of fibers in the reinforcement portion (310) each have a weight average fiber length not shorter than 0.4 mm and not longer than 7.0 mm and have such an orientation property that orientations thereof are aligned in a foot length direction.