Warp Knitting Compound Needle Edge Profile
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Solution Overview
Problem
Warp knitting machines experience faults and breakage due to high loads from inflexible threads, particularly when producing fabrics like mosquito nets, as existing compound needles are not adequately designed to absorb these stresses effectively.
Innovation Solution
The compound needle is reinforced with a predetermined edge profile that increases in cross-section from the hook to the shank, featuring a curved or chamfered design to facilitate smoother stitch transfer, with a ratio of cross-sectional area to surface area optimized to reduce stress concentrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the pusher needle is reinforced to withstand high stresses from stiff yarns, then the strength increases, but the needle becomes more prone to breakage due to stress concentrations at sharp edges
Solution Approach 1:
The invention applies curvature by rounding the edges of the pusher needle, specifically at the transition area between the hook and shank. This rounding eliminates sharp corners that would create stress concentrations, allowing the needle to withstand high stresses from stiff yarns without breaking while maintaining reinforced strength
2Ease of manufacture
If the pusher needle is stamped from sheet metal or hammered from wire, then the ease of manufacture improves, but the needle develops burrs and sharp edges that increase stress concentrations
Solution Approach 1:
The invention addresses the manufacturing precision issue by specifying that edges must be rounded with a defined radius. This can be achieved through additional processing steps after stamping or hammering, eliminating burrs and sharp edges that would otherwise create stress concentrations and lead to needle failure
Solution Approach 2:
The invention changes the geometric parameters of the needle edges by defining specific rounding radii for different areas. This parameter change transforms the sharp-edged geometry from conventional manufacturing into a rounded geometry that distributes stresses more evenly, resolving the contradiction between ease of manufacture and manufacturing precision
3Ease of operation
If the transition area has a small cross-section, then the ease of operation improves for thread passage, but the stress concentration increases leading to needle failure
Solution Approach 1:
The invention applies curvature to the transition area between hook and shank, rounding the edges to eliminate stress concentrations. This allows the transition area to maintain a smaller cross-section for easy thread passage while the rounded edges prevent stress buildup that would lead to needle failure
Solution Approach 2:
The invention applies different edge rounding radii to different areas of the needle. The transition area has specific rounding characteristics that balance ease of operation with stress distribution, while other areas have different rounding parameters optimized for their specific functions
Data Source
Figure 1a~2a
Figure 1b~2b
Figure 3a~3c
AI summary
A warp knitting machine push needle (1) is described, comprising a needle head (2) with a hook (3), a transition area (4) adjoining the hook (3) whose cross-section increases in one direction away from the needle head (2), and a shank (5). This allows the warp knitting machine to be operated reliably even with difficult-to-process yarns. For this purpose, the transition area (4) is provided with an edge profile (14, 15) that changes continuously between the hook (3) and the shank (5).