Perforated Midsole with Sealed Sheets for Variable Cushioning
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Solution Overview
Problem
Conventional athletic footwear midsoles lack variability in properties across different regions, which can lead to inadequate ground reaction force attenuation and control of foot motions, particularly in areas like the heel and forefoot.
Innovation Solution
A midsole element with a plurality of vertically extending bores, sealed by upper and lower sheets, which can be positioned in various configurations to vary the compressibility and stability across different regions, including the heel and forefoot, using polymer foam material and potentially incorporating fluid-filled bladders or stability devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a uniform midsole structure is used throughout the footwear, then manufacturing is simple and cost-effective, but ground reaction force attenuation and foot motion control are inadequate in specific areas like heel and forefoot
Solution Approach 1:
The midsole is divided into multiple regions with different foam densities. The heel area uses a first density foam material for maximum cushioning during heel strike, while the forefoot area uses a second density foam material for energy return during toe-off. This local differentiation optimizes ground reaction force attenuation in each specific area without requiring complex manufacturing processes.
Solution Approach 2:
The midsole is segmented into distinct density zones and functional regions. Stability devices are strategically positioned in specific areas to control pronation where needed. This segmentation allows each region to perform its specialized function while maintaining overall midsole integrity and relatively simple manufacturing through modular construction.
2Reliability
If dual-density polymer foams are used to vary midsole properties, then ground reaction force attenuation improves in different areas, but device complexity increases
Solution Approach 1:
The patent combines dual-density foam construction with integrated stability devices into a unified midsole system. The different density foam regions are merged with strategically placed stability elements to create a coordinated structure that controls foot motion and attenuates ground reaction forces simultaneously, reducing the need for separate components and simplifying overall device complexity.
Solution Approach 2:
The midsole utilizes composite construction combining polymer foam materials of different densities with stability devices. This composite approach allows optimization of mechanical properties in different regions while maintaining structural integrity. The composite materials provide both cushioning and stability functions within a single integrated midsole structure.
3Reliability
If stability devices are added to control pronation, then foot motion control improves, but manufacturing complexity and cost increase
Solution Approach 1:
Stability devices are positioned locally in specific areas of the midsole where pronation control is most needed, such as the medial side near the arch. This targeted placement provides effective foot motion control only where required, rather than uniformly throughout the entire midsole, thereby reducing overall device complexity and manufacturing cost while maintaining necessary stability functions.
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 ground reaction force attenuation and control of foot motions by varying the compressibility and stability across different regions, improving comfort and performance in athletic activities.
Implementation Method 1
Suitable polymer foam materials for the midsole include ethylvinylacetate or polyurethane that compress resiliently under an applied load to attenuate ground reaction forces
Implementation Method 2
Another manner of varying the properties of the midsole involves the use of fluid-filled bladders
Data Source
AI summary
An article of footwear is disclosed that includes an upper and a sole structure secured to the upper. The sole structure includes a midsole element, an upper sheet, and a lower sheet. The midsole element has an upper surface and an opposite lower surface. In addition, the midsole element defines a plurality of bores extending from the upper surface to the lower surface. The upper sheet is secured to the upper surface and extends over at least a portion of the bores. The lower sheet is secured to the lower surface, and the lower sheet is positioned to correspond in location with the upper sheet and extend under the portion of the bores.