Athletic Shoe Shell for Foot Stability and Energy Return

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Solution Overview

Problem

Existing athletic shoes lack effective control over the support phase during impact, particularly at the heel, leading to inefficient energy dissipation and foot displacement.

Innovation Solution

A plastic or composite shell is integrated between the upper and comfort sole, providing torsional and flexural rigidity to counteract foot displacement and restore energy by elastic deformation, with adjustable stiffness through notches and a perforated design for varying running conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the upper is in direct contact with the comfort sole at the heel, then the structure is simple, but the support phase control and foot stability are insufficient

Engineering Contradiction:
Improvestructure simplicityVSAvoidsupport phase control
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

A shell made of plastic or composite material is inserted between the upper and the comfort sole at the heel area. This intermediary shell provides torsional and flexural rigidity to control foot displacement during impact, thereby improving support phase control without significantly complicating the overall structure.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The shell is made of plastic or composite material that combines rigidity for structural support with elasticity for energy return. This composite material approach allows the shell to provide both structural integrity and functional performance in the support phase.

Inventive Principle:
Principle #40Composite materials

2Reliability

If a rigid shell is inserted between the upper and comfort sole, then foot displacement is controlled and stability is improved, but energy dissipation increases

Engineering Contradiction:
Improvefoot stabilityVSAvoidenergy dissipation
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The shell is designed with specific elastic properties that allow it to deform under impact and return energy during the relaxation phase. By carefully selecting materials and designing the shell geometry, the energy dissipation is optimized to provide stability while maintaining efficient energy return for propulsion.

Inventive Principle:
Principle #35Parameter changes

3Strength

If the shell side forms an edge around the shell bottom, then torsional and flexural rigidity is increased, but weight increases

Engineering Contradiction:
ImproverigidityVSAvoidshell weight
Core Design Contradiction:
StrengthVSWeight of moving object

Solution Approach 1:

The shell side is equipped with notches that divide it into separate sections. This segmentation allows the shell to maintain rigidity where needed while reducing material usage and weight. The notches create flexibility between sections while preserving structural integrity in critical areas.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The shell side forms a complete edge around the shell bottom in certain areas to maximize rigidity, while incorporating notches in other areas to reduce weight and provide flexibility. This local quality approach optimizes the balance between strength and weight by applying different structural characteristics in different locations.

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 shell enhances stability and energy return, allowing for faster and more powerful strides by maintaining foot alignment and reducing energy dissipation, suitable for different running types such as road, track, and trail running.

Implementation Method 1

By elastically deforming, it also allows a fraction of the energy released by the shock to be restored during relaxation by reducing the fraction of energy dissipated by the comfort sole

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Implementation Method 2

The curvature of the comfort sole eliminates the overlap effect of the initial impact felt with a comfort sole without curvature. The transition between the impact and the roll of the foot is instantaneous. Combined with the stiffness of the composite shell, the bend of the comfort sole promotes the return of energy

Methodology Applied
Scientific EffectCurvature effect: Geometry

Data Source

PatentEP3723533B1Athletic shoe with a shell inserted between the upper and a comfort sole
Publication Date: 2024.07.17 NORTH FACE APPAREL CORP
  • EP3723533B1 patent drawingFigure 1~3
  • EP3723533B1 patent drawingFigure 2
  • EP3723533B1 patent drawingFigure 4~6

AI summary

An athletic shoe extending between toe (1) and heel (3) and comprising upper (5) attached to outsole (7) via comfort sole (9). According to the invention, the athletic shoe comprises shell (13) make of plastic or composite material, inserted between upper (5) and comfort sole (9) and to which it is attached at heel (1).