Warp Knitting Machine Needle Shank Geometry for Stitch Quality
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Solution Overview
Problem
High-speed warp knitting machines face challenges in producing high-quality elastic knitted fabrics due to oscillating warp threads, which result in quality losses, and optimizing knitting tool movements to address this often limits the product range.
Innovation Solution
A compound needle arrangement with a needle shank thicker than the needle head, featuring a cylindrical configuration and a slider that maintains the stitch size by ensuring the combined circumference of the needle head and slider does not exceed the needle shank's circumference, preventing stitch widening and allowing for high productivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the compound needle stroke is reduced to increase working speed, then productivity is improved, but the stitch quality deteriorates due to insufficient time for stitch formation and widening
Solution Approach 1:
The stitch is pre-widened at the beginning of the compound needle stroke while the needle is in the lowered position, before the actual knitting action occurs. This preliminary widening ensures that even with a short needle stroke (maximum 10 mm), there is sufficient space for the stitch to form properly without requiring a long needle movement, thus maintaining both high productivity and stitch quality
Solution Approach 2:
The needle shank diameter is made variable along its length, being larger at the lower end (where the stitch sits) and smaller at the upper end. This dynamic geometry allows the stitch to be accommodated in a compact space, enabling short needle strokes while maintaining proper stitch formation. The asymmetric needle shank design optimizes the space utilization for stitch holding
2Manufacturing precision
If the needle shank is made thicker to prevent stitch widening, then stitch quality is improved, but the device complexity increases
Solution Approach 1:
The needle shank is designed with non-uniform thickness, being thicker only in the specific region where the stitch is located (lower end), while the upper end remains thinner. This local quality variation provides the necessary stitch containment exactly where needed, without unnecessarily increasing the overall needle dimensions or complexity throughout the entire needle structure
Data Source
Figure 1~4
AI summary
A warp knitting machine is described with a plurality of slide needle assemblies, each comprising a slide (11) and a slide needle (3) with a needle head (8) and a needle shank (10), wherein the warp knitting machine has a slide needle stroke of a maximum of 10 mm. The aim is to enable high productivity of the warp knitting machine while maintaining good quality of the knitted fabric. For this purpose, the needle shank (10) is provided that, at least at the end (15) of a sliding area where the loop is located at the end of a slide needle stroke, the circumference is at least as large as the largest parallel circumference of the entire assembly of needle head (8) and slide (11) in the closed position.