Latch Needle Rotating Axle Pin Form Fit Wear Distribution
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Solution Overview
Problem
Existing latch needles in textile machines face challenges in combining high precision with good wear resistance due to concentrated bearing wear and quality issues in mass production, particularly with pivot pins that rely on press fits which can be difficult to manufacture accurately.
Innovation Solution
A latch needle design featuring a rotationally fixed axis pin with a non-round cross-section that provides a form fit with the latch hole, ensuring a non-rotatable connection and distributing friction and wear over a larger area, thereby enhancing durability and precision, and optionally incorporating a captive device to prevent axial displacement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a press fit connection is used between the pivot pin and latch hole, then the pivot pin is secured axially, but manufacturing precision and quality consistency become problematic in mass production
Solution Approach 1:
The invention changes the geometric parameters of the pivot pin by providing at least one non-circular section with a cross-section that corresponds to the latch hole shape. This parameter change transforms the connection mechanism from relying on press fit interference to relying on geometric form fit, thereby improving manufacturing precision and quality consistency while maintaining reliable axial securing
Solution Approach 2:
The invention applies asymmetry by designing the pivot pin with a non-circular cross-section that matches the asymmetric shape of the latch hole. This asymmetric geometric correspondence creates a form-fit connection that is easier to manufacture with consistent quality compared to symmetric circular press-fit connections, resolving the contradiction between reliability and manufacturing precision
2Device complexity
If bearing wear is concentrated in small areas, then the structure is simpler, but wear resistance and durability are reduced
Solution Approach 1:
The invention extends the bearing surface from a point or small area contact to a larger distributed area by utilizing the non-circular cross-sectional geometry of the pivot pin within the latch hole. This dimensional expansion of the contact interface distributes wear across a larger area, improving durability without significantly increasing structural complexity
Solution Approach 2:
The invention applies different local qualities to different sections of the pivot pin, with at least one section having a non-circular cross-section designed to optimize the bearing surface area. This local geometric modification distributes wear in critical areas while maintaining simplicity elsewhere, resolving the contradiction between device complexity and wear resistance
Data Source
Figure 1~6
Figure 7~9
Figure 10~14
AI summary
The needle has a needle body comprising a needle slot (5) delimited by two slot walls (8, 9). A latch (10) comprises a latch shaft (41) extended into the slot, and a latch hole formed on the latch shaft. The latch hole is positioned in alignment with wall holes (26) that are provided in the slot walls. A swivel pin is extended through the latch hole into the wall holes and is non-rotationally held in the latch hole, where cross-section of the latch hole is formed in non-round shape.