Double-Layer Circular Knit Footwear Upper
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Solution Overview
Problem
Conventional footwear manufacturing is labor-intensive and inefficient due to the need for cut-sew-assembly operations, with design limitations and production inefficiencies inherent in flat knitting technologies.
Innovation Solution
A double-layer circular knitted footwear article with an outer and inner knit layer, where the inner knit layer is monolithically knit to the outer layer, and binding yarns or adhesive materials are used to consolidate the layers, reducing distortion and assembly steps by forming a stable, three-dimensional shape that conforms to the foot anatomy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If flat bed knitting is used to form planar knitted fabric blanks, then material utilization increases due to minimized fabric cutting, but design limits and production inefficiencies occur
Solution Approach 1:
The patent transitions from two-dimensional flat bed knitting to three-dimensional circular knitting. The circular knitting machine knits the upper in a tubular form that already incorporates three-dimensional shaping, eliminating the need for flat fabrication followed by complex folding and assembly operations. This dimensional change enables both high material utilization and improved production efficiency.
Solution Approach 2:
The circular knitting process performs preliminary shaping actions during the knitting itself. The tubular knit structure is formed with pre-defined three-dimensional geometry, including curved panels and structural contours, before any assembly operations. This preliminary formation of complex shapes during knitting reduces subsequent assembly steps and improves productivity.
2Ease of manufacture
If conventional cut-sew-assembly operations are used to manufacture footwear, then assembly flexibility is maintained, but labor intensity and manufacturing complexity increase
Solution Approach 1:
The patent merges multiple separate manufacturing operations (cutting, shaping, and initial assembly) into a single circular knitting process. The knitting machine simultaneously creates the tubular structure, forms three-dimensional panels, and prepares the upper for sole attachment, reducing the number of discrete manufacturing steps and overall complexity.
Solution Approach 2:
The circular knitting machine performs multiple functions that would traditionally require separate operations. It knits the upper material, forms three-dimensional shapes, creates structural panels, and prepares the assembly for sole attachment, making the manufacturing process more universal and less complex.
3Productivity
If flat knitted uppers are formed and then folded or wrapped into shoe uppers, then fewer sewing steps are required, but design limits and production inefficiencies remain
Solution Approach 1:
The patent uses circular knitting to create three-dimensional tubular structures with inherent spatial complexity, rather than folding two-dimensional flat fabric. This enables complex panel configurations and anatomical shaping to be directly knit in three-dimensional space, providing both design flexibility and production efficiency.
Solution Approach 2:
The circular knitting process allows dynamic adjustment of knitting parameters (needle selection, yarn feed, stitch patterns) to create varied panel structures, densities, and three-dimensional forms within a single continuous operation. This parameter flexibility enables diverse design configurations without sacrificing productivity.
Data Source
AI summary
An aspect of the disclosure is a footwear article. The footwear article includes a double layer knitted upper having a foot bed, an upper portion continuous with the foot bed, an ankle opening, and an inner void for receiving a foot of a wearer. The double layer knitted upper has an outer knit layer defining an exterior surface of the double layer knitted upper. The double layer knitted upper also has an inner knit layer monolithically knit to the outer knit layer. The inner knit layer has a plurality of inner knit regions that spatially correspond to the plurality of outer knit regions of the outer knit layer. The outer knit layer and the inner knit layer substantially define the foot bed and the upper portion of the double layer knitted upper.