Thermoformed Siped Footwear Sole with Multi-Layer Construction
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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, siping, and customized stiffness and flexibility.
Innovation Solution
The method involves thermoforming a sole structure with a thermoplastic base layer and outer layer, incorporating sipes and protuberances, which are formed post-molding and adhered to the upper, allowing for unique geometries and multi-material constructions that would be cost-prohibitive or impossible with traditional methods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional injection or compression molding is used to manufacture the sole structure, then the manufacturing process is simple and cost-effective, but the design complexity is limited and multi-material geometries cannot be achieved
Solution Approach 1:
The sole structure is divided into multiple layers including a base layer and an outer layer, each capable of being manufactured separately and then bonded together. This segmentation allows each layer to be optimized independently for different materials and geometries while maintaining manufacturing feasibility
Solution Approach 2:
The patent transitions from traditional single-layer molding to a multi-layer construction approach, adding the dimension of layering. This enables complex multi-material geometries by stacking simpler manufactured layers, effectively solving the contradiction between manufacturing simplicity and design complexity
2Adaptability or versatility
If the sole structure is molded with undercuts to achieve unique geometries, then the design versatility is improved, but the molding process becomes difficult or impossible
Solution Approach 1:
By segmenting the sole into multiple layers, the patent avoids the need to mold complex undercut geometries in a single piece. Each layer can be molded with simpler geometries and then assembled to create the final complex shape with undercut features
Solution Approach 2:
The base layer and outer layer are manufactured separately beforehand with their respective geometries, allowing undercut features to be created in the assembly process rather than requiring complex single-step molding
3Reliability
If sipes are incorporated into the sole structure to enhance natural motion response, then the performance is improved, but the manufacturing complexity increases
Solution Approach 1:
Sipes are incorporated into specific layers (particularly the outer layer) rather than the entire sole structure. This localized segmentation allows sipes to be added only where needed for performance while keeping other areas simple for manufacturing
Solution Approach 2:
The patent applies siping selectively to specific regions and layers of the sole structure where natural motion response is needed, rather than uniformly throughout. This local quality approach enhances performance where required while maintaining manufacturing simplicity in other areas
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 approach enables the creation of sole structures with enhanced natural motion response, customized stiffness, and visual characteristics, overcoming the limitations of traditional molding techniques by allowing for splayed sipes and multi-material designs that provide improved fit and performance.
Implementation Method 1
The outer layer is heated to a forming temperature and molded to a desired geometry
Implementation Method 2
The heated outer layer is pressed against an upper and cooled to set a formed geometry
Data Source
AI summary
An article of footwear includes an upper coupled to a sole structure. The upper has a ground facing surface, and opposing medial and lateral sidewalls disposed on and extending from opposite medial and lateral sides of the ground facing surface. The sole structure is formed from a plurality of non-coextensive, thermoplastic foam layers, where each layer extends across a portion of the ground facing surface of the upper. These layers include at least a first foam layer and a second foam layer. The first foam layer has a different hardness and/or density than the second foam layer. Each of the first foam layer and the second foam layer extends into direct contact with, and is directly adhered to the lateral sidewall and the medial sidewall of the upper, and the first foam layer is secured to the second foam layer via an adhesive or a thermal weld.