Dual Layer Auxetic Footwear Sole with Independent Expansion

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Solution Overview

Problem

Current footwear sole structures lack efficient mechanisms for independent auxetic behavior in both insole and outsole layers, limiting their ability to adapt to various foot motions and ground conditions effectively.

Innovation Solution

A sole system comprising a first auxetic layer with a pattern of apertures and a second auxetic layer with projections, where the first layer is disposed on top of the second, allowing each layer to expand independently in lateral and longitudinal directions when tension is applied, enhancing cushioning and traction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a single-layer sole structure is used, then the structure is simple and easy to manufacture, but it cannot provide independent auxetic behavior in both insole and outsole layers

Engineering Contradiction:

Improveindependent auxetic behaviorVSAvoidsole structure complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The sole structure is divided into two separate auxetic layers: a first auxetic layer (insole) and a second auxetic layer (outsole). Each layer can be configured with different aperture patterns, materials, and auxetic behaviors to independently respond to foot motions and ground conditions, resolving the contradiction between adaptability and complexity by organizing the system into functional segments.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The first auxetic layer is disposed on top of the second auxetic layer, with the pattern of apertures in the first layer configured to receive the pattern of projections in the second layer. This nested arrangement allows both layers to maintain their independent auxetic behaviors while being integrated into a unified sole structure.

Inventive Principle:

Principle #7Nested doll (Nesting)

2Adaptability or versatility

If the aperture pattern in the first auxetic layer is tightly fitted to the projection pattern in the second auxetic layer, then the layers are securely connected, but the auxetic behaviors of the two layers become coupled and cannot occur independently

Engineering Contradiction:

Improveindependent auxetic behaviorVSAvoidlayer connection strength

Core Design Contradiction:

Adaptability or versatilityVSStrength

Solution Approach 1:

The connection between the first and second auxetic layers is made selective and localized rather than uniform. The pattern of apertures in the first layer is configured to receive the pattern of projections in the second layer, creating localized connection points that provide sufficient mechanical coupling while leaving other areas free to move independently, thus preserving independent auxetic behaviors.

Inventive Principle:

Principle #3Local quality

3Reliability

If the sole structure uses traditional non-auxetic materials, then the manufacturing is simpler, but the cushioning and traction performance is limited

Engineering Contradiction:

Improvecushioning and traction performanceVSAvoidmanufacturing complexity

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent changes the structural parameters of the sole layers by introducing auxetic geometries with specific aperture patterns and projection configurations. These geometric parameter changes enable the materials to exhibit auxetic behavior (negative Poisson's ratio) where the material expands laterally when stretched, providing enhanced cushioning and traction performance without fundamentally changing the manufacturing process.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The sole structure utilizes composite construction with two different auxetic layers made from potentially different materials optimized for their specific functions. The first auxetic layer (insole) and second auxetic layer (outsole) can be made from different polymer compositions or material formulations, allowing each layer to be optimized for its specific performance requirements while maintaining manufacturability.

Inventive Principle:

Principle #40Composite materials

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 system provides improved cushioning and traction by allowing each layer to respond dynamically to foot motions and ground conditions, offering enhanced comfort and performance.

Implementation Method 1

the first auxetic layer includes a pattern of apertures and exhibits a first auxetic behavior, and where the second auxetic layer includes a pattern of projections and exhibits a second auxetic behavior

Methodology Applied

Scientific EffectAuxetic behavior: Auxetic Materials

Data Source

PatentUS11039657B2Dual layer sole system with auxetic structure

Publication Date: 2021.06.22 NIKE INC

AI summary

A sole structure including a first layer and a second layer is disclosed. The first layer includes a set of apertures arranged in an auxetic configuration that permits the first layer to exhibit a first auxetic behavior. The second layer includes a set of projections arranged in an auxetic configuration that permits the second layer to exhibit a second auxetic behavior. The first layer and the second layer may be joined together in a manner that allows the first auxetic behavior to occur independently of the second auxetic behavior.