Fluid-Filled Bladder for Footwear Midsole
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Solution Overview
Problem
Conventional polymer foam midsoles in athletic footwear lose compressibility and force attenuation characteristics over time due to cell structure deterioration from repeated compressions, leading to decreased performance.
Innovation Solution
A fluid-filled bladder with a tessellation configuration, made from thermoplastic polymer materials, is encapsulated within the polymer foam midsole, providing improved durability and maintaining force attenuation by using a pressurized fluid to maintain shape and support.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If polymer foam material is used for midsole, then initial force attenuation is provided, but force attenuation characteristics decrease over time due to cell structure deterioration
Solution Approach 1:
The patent replaces the deteriorating polymer foam cell structure with a fluid-filled bladder system. The bladder is inflated to a predetermined pressure and encloses a fluid that provides consistent force attenuation over time. The fluid pressure is maintained within a range of 5-50 psi to optimize both comfort and durability, eliminating the degradation issue inherent in foam materials.
Solution Approach 2:
The patent changes the physical state of the midsole from a solid foam structure to a pressurized fluid system. By controlling the fluid pressure parameter (5-50 psi), the system maintains optimal force attenuation characteristics throughout the product lifespan, unlike foam whose properties deteriorate with repeated compression.
2Ease of manufacture
If conventional polymer foam midsole is used, then manufacturing is simple, but material waste and energy consumption are high
Solution Approach 1:
The patent uses a thin elastomeric bladder wall instead of bulk polymer foam material. This thin-film approach significantly reduces material consumption while providing the same or better functional performance. The bladder can be manufactured using extrusion or molding processes that are efficient and generate minimal waste.
Solution Approach 2:
The patent extracts the essential force attenuation function from the bulk foam material and concentrates it into a pressurized fluid system within a thin bladder. This extraction eliminates the need for large amounts of foam material, reducing both material waste and manufacturing energy consumption.
3Strength
If fluid pressure is increased in the bladder, then force attenuation is improved, but comfort may be compromised
Solution Approach 1:
The patent establishes an optimal fluid pressure range of 5-50 psi that balances force attenuation performance with wearer comfort. This parameter optimization ensures that the bladder provides sufficient support and durability while maintaining comfort levels comparable to or better than conventional foam midsoles.
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 fluid-filled bladder maintains the midsole's compressibility and force attenuation characteristics over the lifespan of the footwear, enhancing comfort and performance by minimizing material waste and energy consumption in manufacturing.
Implementation Method 1
The bladder encloses a pressurized fluid between the first surface and the second surface
Implementation Method 2
A first sheet and a second sheet of a thermoplastic polymer material are bonded together
Data Source
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AI summary
An article of footwear comprising an upper and a sole structure secure to the upper, at least one of the upper and the sole structure incorporating a bladder (80) that includes a first surface and an opposite second surface that are peripherally joined to form six edges that define a hexagonal shape for the bladder, the bladder including a tensile member (95) located within the bladder and joined to the first surface and second surface. The bladder includes an inflation area (94) formed by a bond that is adjacent to the periphery of the bladder.