Sole Plate Forefoot Through Hole for Zoned Cushioning
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Solution Overview
Problem
Current footwear sole structures lack effective tuning for energy absorption and return, particularly in areas like the metatarsal heads and hallux, leading to inconsistent cushioning and stiffness across different zones of the foot.
Innovation Solution
A midsole system with a sole plate featuring a through hole that tapers in width, combined with first and second foam layers of varying compressive stiffness, and a sole plate made of materials like fiber strand-lain composite or thermoplastic elastomer, which allows for differential energy absorption and return at the through hole compared to other areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a uniform sole structure is used across the entire foot, then manufacturing is simple, but cushioning and stiffness are inconsistent across different zones
Solution Approach 1:
The sole plate incorporates a through hole in the forefoot region to create local structural differentiation. This allows the forefoot area to have reduced stiffness and enhanced cushioning properties, while the rest of the sole plate maintains its structural integrity and stiffness. The through hole specifically targets the metatarsal head region to provide localized compliance without compromising overall sole performance.
Solution Approach 2:
The sole plate is segmented into distinct functional zones by introducing the through hole, dividing the forefoot region from the midfoot and heel regions. This segmentation allows each zone to have different mechanical properties - the forefoot zone gains compliance through the hole while other zones maintain structural rigidity, resolving the contradiction between uniform manufacturing and zoned performance.
2Strength
If the sole plate is made stiffer to provide motion control, then stability improves, but cushioning under the metatarsal heads deteriorates
Solution Approach 1:
The through hole creates a localized compliant zone directly under the metatarsal heads, allowing this specific area to provide cushioning while the rest of the sole plate maintains its stiffness for motion control. This local modification resolves the contradiction by providing different mechanical properties where needed rather than uniformly across the entire sole.
3Use of energy by moving object
If foam layers are added to enhance cushioning, then energy absorption improves, but device complexity increases
Solution Approach 1:
The through hole creates a porous/open structure in the sole plate that allows foam layers to be strategically positioned and compressed. This porous approach enables enhanced energy absorption in the forefoot region without requiring foam throughout the entire sole, thus improving energy absorption while limiting the increase in device complexity to specific zones only.
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
This configuration provides a softer cushioning feel under the metatarsal heads and hallux while maintaining stiffness elsewhere, enhancing energy absorption and return during dynamic loading, thereby improving comfort and performance.
Implementation Method 1
The first foam layer and the second foam layer may resiliently deform under a dynamic compressive load and may return energy upon removal of the dynamic compressive load
Implementation Method 2
The resilient deformation and the energy absorption may thus be different at the through hole than away from the through hole
Implementation Method 3
A softer cushioning feel may be experienced by a foot supported on the sole structure at the through hole (i.e., above the through hole) than away from the through hole
Data Source
Figure 1
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AI summary
A sole structure (14) for an article of footwear (112,12) may have a midsole (160,60) system that includes a sole plate (10) having a forefoot region (16) and a midfoot region (18). The sole plate (10) may have a foot-facing surface and a ground-facing surface opposite to the foot-facing surface. The sole plate (10) may define a trough hole (35) extending from the foot-facing surface to the ground-facing surface in the forefoot region (16). The trough hole (35) may be closer to a medial edge (32) of the sole plate (10) than to a lateral edge (34) of the sole plate (10). The sole plate (10) may have ridges (40A, 40B, 40C, 40D, 40) extending longitudinally in the midfoot region (18) and the forefoot region (16). The ridges (40A, 40B, 40C, 40D, 40) may have crests (44A, 44B, 44C, 44D, 44) at least some of which may extend non-parallel with one another in a longitudinal direction of the sole plate (10).