Warp Knit Elastomeric Fabric Balanced Stretch
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Solution Overview
Problem
Existing warp knit elastomeric fabrics face challenges in achieving balanced stretch and power characteristics, with prior art methods resulting in unbalanced stretch ratios and undesirable durability issues such as core retraction, slip back, and frayed edges, while also being costly due to the need for specialized weft insertion machines.
Innovation Solution
A method using a standard warp knitting machine with a rigid yarn on one guidebar, a small spandex yarn knit in on the second guidebar, and a large spandex yarn laid in on the third guidebar, creating a fabric with improved durability and balanced stretch characteristics without requiring expensive weft insertion machines.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If large deniers of elastic yarn are used in raschel knit fabrics to achieve substantial power, then power characteristics are improved, but stretch ratio becomes unbalanced (5:1 warp to fill)
Solution Approach 1:
The patent applies local quality by using different denier elastic yarns in different locations (different guidebars) of the fabric structure. Specifically, it combines large denier elastic yarn (providing power) with small denier elastic yarn (providing stretch balance) in a multi-guidebar construction, allowing each region to contribute its specific property to the overall fabric performance.
2Manufacturing precision
If small deniers of elastic yarn are used in tricot constructed fabrics to achieve balanced stretch, then stretch balance is improved, but power characteristics deteriorate (minimal power generated)
Solution Approach 1:
The patent merges the advantages of both large and small denier elastic yarns by combining them in a single multi-guidebar fabric construction. The fabric integrates small denier yarns (for stretch balance) and large denier yarns (for power) in different guidebars, achieving both balanced stretch and substantial power characteristics simultaneously.
3Reliability
If weft insertion technique is used to achieve better durability and square performance, then durability and stretch balance are improved, but manufacturing cost increases (requires expensive weft insertion machine)
Solution Approach 1:
The patent copies the desirable performance characteristics of weft insertion fabrics (durability and balanced stretch) using a different manufacturing approach. By using a standard warp knitting machine with a specific multi-guidebar construction combining knit-in and laid-in elastic yarns, it replicates the performance benefits of expensive weft insertion fabrics without requiring specialized equipment.
4Ease of manufacture
If prior art warp knitting techniques are used, then manufacturing cost is reduced (standard machine), but durability characteristics deteriorate (core retraction, slip back, frayed edges)
Solution Approach 1:
The patent uses composite material principles by combining multiple types of yarns (rigid inelastic yarn and elastic yarns of different deniers) in a multi-guidebar warp knitting construction. This composite structure, with specific stitch patterns interlocking the yarns, produces a fabric that exhibits improved durability characteristics including resistance to core retraction, slip back, and frayed edges, while still using standard warp knitting machinery.
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 resulting fabric exhibits enhanced durability, balanced stretch, and desirable power characteristics, with optimal flex durability ratings even after multiple launderings, and is less bulky and cost-effective compared to traditional methods, while eliminating issues like core retraction and frayed edges.
Implementation Method 1
a small spandex yarn knit in on the second guidebar and a large spandex yarn laid in on the third guidebar
Data Source
AI summary
An improved elastomeric fabric that is knitted with three guidebars on a warp knitting machine including a non-elastic yarn that is knit in on the first guidebar, a first elastic yarn that is knit-in on the second guidebar, and a second elastic yarn that is laid-in on the third guidebar. The elastic yarn has a denier in the range from about 20 to about 105 and the second elastic yarn has a denier in the range from about 70 to about 560. The fabric provides improved durability and power characteristics. The fabric can also be constructed to have improved stretch characteristics such as substantially square stretch or unbalanced stretch with greater fill (width) stretch than warp (length) stretch.