Footwear Sole Assembly Using Segmented Preforms to Prevent Color Bleeding
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Solution Overview
Problem
Conventional midsoles in athletic footwear often suffer from color bleeding between different material layers during molding, which affects the aesthetic appeal and makes it difficult to achieve varying physical properties and performance characteristics in different regions of the sole assembly.
Innovation Solution
A sole assembly formed from two preforms of different materials and colors, where the interfaces between these preforms are positioned along central portions of the sidewalls to minimize visible bleeding, allowing for customized physical properties and improved aesthetics by using a mold assembly where preforms are partially melted and bonded to form a midsole with distinct regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple colored portions are formed in a mold assembly, then the sole assembly can have varied aesthetic appearance and performance characteristics, but color lines between different colored portions bleed during molding
Solution Approach 1:
The sole assembly is divided into multiple preforms, each made from a different colored material. These preforms are positioned in separate cavity areas of the mold assembly before injection molding. By segmenting the sole into distinct preform units rather than attempting to mold multiple colors in a single cavity, the patent prevents color bleeding while maintaining aesthetic versatility and performance variation across different regions.
Solution Approach 2:
The preforms are prepared and positioned in the mold assembly before the injection molding process begins. This preliminary placement of colored material segments allows the subsequent injection material to bond to predefined positions, ensuring sharp color lines are maintained throughout the molding process without bleeding between different colored portions.
2Ease of manufacture
If conventional molding methods are used with multiple materials, then manufacturing complexity increases, but color bleeding occurs and aesthetic appeal decreases
Solution Approach 1:
The manufacturing process is simplified by segmenting the multi-material sole into separate preforms that are pre-positioned in the mold. This approach avoids the complexity of simultaneous multi-material injection while preventing color bleeding, as each preform maintains its distinct color boundary during the bonding process.
Solution Approach 2:
The preforms are prepared and positioned in advance before the injection molding operation. This preliminary action ensures that color lines remain well-defined during molding, eliminating the need for complex real-time multi-material injection control while maintaining manufacturing efficiency and aesthetic quality.
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 reduces visible color bleeding, enhancing the aesthetic appeal and allowing for tailored performance characteristics in different regions of the sole assembly, such as shock-attenuation and energy-absorption, suitable for various footwear styles.
Implementation Method 1
the preforms are partially melted and bonded to form a midsole
Implementation Method 2
the preforms are partially melted and bonded
Data Source
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AI summary
An article of footwear includes an upper and a sole assembly positioned beneath the upper. The sole assembly has a vertically extending channel formed in its bottom surface inward of a periphery of the sole assembly, the channel including opposed sidewalls and an end surface. The sole assembly includes a first portion having a first color; and a second portion having a second color that is different than the first color. An interface between the first portion and the second portion is positioned at a central portion of one of the sidewalls of the channel. A method of forming such an article of footwear is also disclosed.