Strand-Wound Bladder for Footwear Midsole Expansion Control
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Solution Overview
Problem
Conventional athletic footwear midsoles lack effective means to control the expansion of pressurized fluid chambers, which can lead to reduced cushioning and stability due to uncontrolled stretching of the fluid bladder.
Innovation Solution
A pressure chamber is designed with a bladder partially formed from a polymer material sealed to enclose a pressurized fluid, and a strand wound around the bladder to form a tensile restraining structure, limiting the expansion of the bladder when pressurized, and this configuration is integrated into the midsole of the footwear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a fluid-filled chamber is used in the midsole to enhance ground reaction force attenuation, then cushioning performance is improved, but the chamber tends to expand uncontrollably when pressurized, reducing stability
Solution Approach 1:
Strands are wound around the bladder in a predetermined pattern before the bladder is fully pressurized, establishing a tensile restraining structure that pre-limits the expansion directions. This preliminary action prevents uncontrolled shape changes during subsequent pressurization while maintaining cushioning effectiveness.
Solution Approach 2:
The patent changes the physical state and arrangement of reinforcing elements by winding strands around the bladder in specific patterns (e.g., helical, circumferential, longitudinal arrangements). This parameter change in strand configuration creates anisotropic reinforcement that controls expansion in specific directions while allowing cushioning in others.
2Use of energy by moving object
If the bladder is pressurized to enhance cushioning, then ground reaction force attenuation is improved, but the bladder expands and loses structural control
Solution Approach 1:
The bladder is constructed as a flexible sealed chamber from elastomeric material that can deform under pressure to provide cushioning. The flexibility of this thin-walled structure allows it to compress and absorb energy while the wound strands provide the necessary structural control to prevent uncontrolled expansion.
Solution Approach 2:
The pressure chamber combines the elastomeric bladder material with wound strands to create a composite structure. This composite construction integrates the flexibility and energy absorption of the elastomeric chamber with the structural control and shape maintenance of the wound strand reinforcement.
3Stability of the object's composition
If strands are wound around the bladder to control expansion, then shape stability is improved, but manufacturing complexity increases
Solution Approach 1:
The reinforcing structure is segmented into discrete strands that are wound around the bladder in specific patterns. This segmentation allows for controlled application of reinforcement in different orientations (circumferential, longitudinal, helical) to address different expansion tendencies in various regions of the bladder.
Solution Approach 2:
The wound strands act as an intermediary element between the pressurized fluid inside the bladder and the external environment. These strands transfer and distribute the internal pressure loads around the bladder, controlling expansion while allowing the bladder to maintain its cushioning function.
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 effectively limits the expansion of the pressurized fluid bladder, enhancing the cushioning and stability of the footwear by maintaining the bladder's shape and providing improved control over the pressure, thereby enhancing the overall performance and comfort.
Implementation Method 1
a bladder at least partially formed from a polymer material that is sealed to enclose a pressurized fluid
Implementation Method 2
a strand wound around the bladder and secured to the bladder... forming a tensile restraining structure
Data Source
Figure 1
Figure 2
Figure 3A
AI summary
An article of footwear or another product may incorporate a pressure chamber that includes (a) a bladder at least partially formed from a polymer material that is sealed to enclose a pressurized fluid and (b) a strand wound around the bladder and secured to the bladder. In manufacturing the pressure chamber, a bladder with an elongate configuration may be formed. A strand is wound around the bladder, and the strand is secured to the bladder. When incorporated to a sole structure of the article of footwear, for example, a portion of the bladder that includes the strands may be exposed at an outer surface of the sole structure.