Footwear Shear Force Reduction via Segmented Coupling Elements
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Solution Overview
Problem
Existing footwear technologies fail to effectively mitigate shear forces applied to the foot, which can lead to blisters, ulcers, and other injuries, particularly in individuals with medical conditions like diabetes, due to high frictional forces and limited cushioning in the horizontal plane.
Innovation Solution
Incorporation of coupling elements in the midsole or outsole that allow for horizontal displacement and differential resistance to movement in various directions, reducing shear forces by distributing the horizontal impulse over a longer period and minimizing frictional forces on the foot.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the upper of the shoe prevents free movement of the foot to provide support, then stability is improved, but high frictional forces are applied to the dorsal aspect of the foot increasing shear forces
Solution Approach 1:
The midsole is segmented into multiple independent cushioning elements rather than a single rigid structure. Each cushioning element can independently deform and return, allowing the midsole to provide support while reducing shear forces through distributed, independent deformation zones.
Solution Approach 2:
The cushioning elements are designed to be dynamically responsive, deforming under load and returning to original shape. This dynamic behavior allows the midsole to adapt to foot movement while maintaining support, reducing static friction forces that would otherwise act on the foot.
2Object-affected harmful factors
If traditional insole designs are used to mitigate shear forces, then some cushioning is provided, but the upper prevents free movement resulting in limited benefit
Solution Approach 1:
The cushioning elements act as an intermediary between the foot and the upper structure. They absorb and dissipate shear forces through controlled deformation, mediating the interaction between the foot and the constraining upper, thereby reducing the transmission of harmful friction forces.
Solution Approach 2:
The midsole utilizes composite construction with multiple cushioning elements made from materials with specific viscoelastic properties. These composite structures provide both cushioning and shear force mitigation while maintaining the structural integrity needed for support.
3Productivity
If repeated forces are experienced during activities such as running on hard surfaces, then athletic performance is maintained, but fatigue and increased risk of injury occur
Solution Approach 1:
The cushioning elements are pre-positioned in the midsole to provide immediate shock absorption upon impact. This beforehand cushioning prepares the footwear system to absorb repeated impact forces during athletic activities, reducing fatigue and injury risk before they can affect the foot and lower extremities.
Solution Approach 2:
The cushioning elements provide continuous shock absorption and shear force mitigation throughout the entire gait cycle. This continuous protective action maintains athletic performance by consistently reducing the cumulative effect of repeated forces on hard surfaces, preventing fatigue and injury over extended periods of activity.
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 solution significantly reduces shear forces on the plantar soft tissue, enhances cushioning, and decreases fatigue, thereby improving comfort and reducing the risk of injury during athletic activities and everyday wear.
Implementation Method 1
minimizing frictional forces on the foot
Implementation Method 2
reduce shear forces applied to the wearer's foot
Data Source
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AI summary
An item of footwear including a sole assembly that comprises at least an outsole and an insole, and further comprising one or more shear force-reducing coupling elements (30) disposed between the insole and the ground. The coupling elements (30) are adapted to permit limited displacement, in a plane parallel, in use, to the ground, of overlying components of the item of footwear. The coupling elements (30) provide less resistance to displacement of overlying components of the item of footwear in a first direction than in a second, reverse direction.