Stacked Sole Cushioning With Segmented Chambers for Gradient Compression
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Solution Overview
Problem
Conventional single-slab polymer foams in footwear midsoles struggle to balance cushioning characteristics, either sacrificing comfort for responsiveness or vice versa, making it difficult to achieve gradient load compression.
Innovation Solution
A sole structure with a midsole featuring segmented cushions and plates, including fluid-filled chambers and carbon fiber plates, to provide customizable cushioning and force distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a single-slab polymer foam is used in the midsole, then the structure is simple and easy to manufacture, but it is difficult to balance cushioning characteristics and achieve gradient load compression from soft to responsive
Solution Approach 1:
The midsole is divided into multiple discrete foam blocks (first foam block, second foam block, third foam block) with different densities and cushioning properties. Each foam block can be independently selected and positioned to create a gradient load compression effect, allowing the forefoot region to be softer while the heel region remains more responsive. This segmentation resolves the contradiction by enabling customized cushioning characteristics without requiring a complex single-slab construction.
Solution Approach 2:
Different regions of the midsole are assigned different foam densities and material properties. The forefoot region uses softer foam blocks for comfort during toe-off, while the heel region uses denser, more responsive foam for impact attenuation. This local differentiation of material properties allows each region to be optimized for its specific function, achieving gradient load compression while maintaining manufacturing simplicity through modular assembly.
2Ease of operation
If polymer foam is made softer to improve comfort, then cushioning is enhanced, but compressibility and ability to attenuate ground-reaction forces after repeated compressions decrease
Solution Approach 1:
The midsole incorporates multiple foam blocks with varying density ratings (e.g., 15-30 pcf for forefoot, 30-60 pcf for heel). Softer foam blocks provide immediate comfort and cushioning, while denser foam blocks maintain structural integrity and compressibility over repeated loading cycles. This segmentation allows the system to deliver both comfort and reliability simultaneously.
Solution Approach 2:
The midsole uses composite construction with different foam materials or foam-density combinations in various regions. By combining softer foam for comfort zones with harder, more resilient foam for load-bearing zones, the system achieves both comfort and sustained compressibility. The composite approach allows each material to contribute its strengths without compromising the other.
3Power
If polymer foam is made harder to improve responsiveness, then energy return is enhanced, but softness and comfort are sacrificed
Solution Approach 1:
The midsole assigns different foam densities to different functional regions: softer foam (15-30 pcf) in the forefoot for comfort during push-off, and harder foam (30-60 pcf) in the heel for impact responsiveness. This local quality differentiation ensures that comfort and responsiveness are optimized in their respective zones without compromising each other.
Solution Approach 2:
The midsole is segmented into distinct foam blocks that can be independently optimized for their specific functions. The forefoot foam blocks prioritize comfort and flexibility, while the heel foam blocks prioritize responsiveness and energy return. This segmentation allows the overall system to achieve both comfort and responsiveness simultaneously.
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
Enhances comfort and responsiveness by allowing for tailored cushioning properties across different regions of the sole, improving overall foot support and impact absorption.
Implementation Method 1
The cushion may include a first fluid-filled chamber disposed between the first plate and the second plate and a second fluid-filled chamber disposed between the second plate and the outsole
Implementation Method 2
a midsole disposed between the outsole and the upper. The midsole provides cushioning for the foot and is generally at least partially formed from a polymer foam material that compresses resiliently under an applied load to cushion the foot by attenuating ground-reaction forces
Data Source
AI summary
A sole structure for an article of footwear is provided. The sole structure includes an outsole having a ground-engaging surface and an upper surface formed on an opposite side of the outsole than the ground-engaging surface. A first cushion is disposed proximate to a medial side of the sole structure and includes a first fluid-filled chamber attached to the upper surface of the outsole and a second fluid-filled chamber attached to the first fluid-filled chamber and disposed between the first fluid-filled chamber and the upper. A second cushion is disposed proximate to a lateral side of the sole structure and includes a third fluid-filled chamber attached to the upper surface of the outsole and a fourth fluid-filled chamber attached to the third fluid-filled chamber and disposed between the third fluid-filled chamber and the upper. The second cushion is fluidly isolated from the first cushion.