Thermoformed Footwear Sole with Sipes for Custom Stiffness
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Solution Overview
Problem
Conventional footwear manufacturing techniques, such as injection or compression molding, restrict design complexity and multi-material geometries, making it difficult to create sole structures with undercuts, sipes, and customized stiffness, which are cost-prohibitive or impossible to produce directly.
Innovation Solution
The intermediate sole structure is thermoformed to the upper, allowing for the creation of unique geometries and multi-material constructions with siping and surface contouring, enabling varied protuberances, directional flexibility, and localized cushioning properties by cutting sipes into a pre-formed thermoplastic sole and adhering it to the upper using a thermoforming process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional molding techniques (injection or compression molding) are used to manufacture the sole structure, then the manufacturing process is simple and direct, but the design complexity is limited and multi-material geometries cannot be achieved
Solution Approach 1:
The sole structure is divided into multiple separate components (outsole, midsole, insole, and additional functional layers) that are manufactured independently and then assembled. This segmentation allows each component to be optimized separately with different materials and geometries, achieving complex multi-material designs that would be impossible with conventional single-step molding
Solution Approach 2:
The patent implements a layered construction where multiple sole components are stacked and assembled in sequence (outsole layer, midsole layer, insole layer, and additional functional layers). Each layer is nested within the overall sole assembly, allowing complex multi-material geometries to be achieved through sequential layering rather than attempting to mold the entire complex structure in a single operation
2Shape
If the sole structure is molded into its final shape through conventional molding, then the manufacturing is straightforward, but undercuts and isolated features cannot be created
Solution Approach 1:
The patent creates sipes (slits or cuts) in the outsole component before the final assembly process. This preliminary action of cutting sipes into the molded outsole allows for complex geometric features to be added after the basic molding operation, avoiding the need to create these features through complex mold designs that would cause undercuts
Solution Approach 2:
By separating the sole into multiple components that are assembled together, the patent can create complex geometries in each component independently using simple molding techniques, then combine them to achieve the final complex shape. This avoids the need to mold the entire complex geometry in a single operation
3Adaptability or versatility
If conventional molding is used to create the sole structure, then the production is efficient, but customized stiffness and localized cushioning properties cannot be achieved
Solution Approach 1:
The patent applies different materials with different properties to different regions of the sole structure. The outsole uses wear-resistant material, the midsole uses cushioning material, and additional functional layers provide localized performance enhancements. This local quality approach allows customized stiffness and cushioning properties in specific areas without requiring complex molding operations for the entire sole
Solution Approach 2:
The patent constructs the sole using multiple different materials assembled in layers, creating a composite structure. Each material layer provides specific performance characteristics (wear resistance, cushioning, flexibility, etc.), allowing customized performance properties to be achieved through material selection and layering rather than through complex molding of a single homogeneous material
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 method allows for the production of sole structures with enhanced natural motion response, customized stiffness, and visual characteristics that are impractical or impossible with traditional molding techniques, providing a more custom fit and improved performance.
Implementation Method 1
The sole structure is heated to permit forming
Implementation Method 2
An adhesive is applied to the inner surface of the pre-formed sole structure
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
An intermediate sole structure (14) for an article of footwear (10) includes a foamed thermoplastic sole component. The foamed thermoplastic sole component has a foamed thermoplastic base layer (50) and a foamed thermoplastic outer layer (52) that is integrally formed with the foamed thermoplastic base layer. The outer layer includes a plurality of sipes (56) extending through the outer layer and terminating at the base layer. The thermoplastic sole component has an inner surface (30) defined by the base layer, an opposite, outer surface (32) defined by the outer layer, and a thickness defined between the inner surface and the outer surface. The inner surface is substantially planar and is operative to be adhered to a ground-facing surface (34) of an upper (12). Additionally, the thickness is smaller at a peripheral edge of the sole component than within a. central region.