Felting Needle Shaft Geometry for Easier Board Insertion
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Solution Overview
Problem
Existing felting needles are difficult to handle manually and mechanically, leading to wear on needle boards and misalignment issues, especially due to the tensioned shank design, which requires tools for insertion and causes bending and kinking stresses.
Innovation Solution
A felting needle design with a shaft featuring a clamping section and a guide section, where the guide diameter is slightly smaller than the clamping diameter, allowing for precise manual insertion and reduced tool-assisted insertion, minimizing wear on needle boards and preventing bending.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the felting needle shaft is held under tension and clamped in the bore of the needle board, then the needle can be securely fixed, but the needle cannot be inserted by hand and requires tools, which is time-consuming and causes wear on the needle board
Solution Approach 1:
The shaft is divided into functionally distinct sections: a clamping section with larger diameter for secure fixation in the needle board bore, and a guide section with smaller diameter for easy manual insertion. This segmentation allows each portion to fulfill its specific function optimally without compromise
Solution Approach 2:
Different sections of the shaft have different diameters tailored to their specific functions. The clamping section has a larger diameter (e.g., 1.8mm) optimized for holding under tension, while the guide section has a smaller diameter (e.g., 1.6mm) optimized for easy insertion. This local differentiation resolves the contradiction between secure fixation and ease of insertion
2Reliability
If the felting needle shaft is held under tension in the needle board bore, then the needle is securely held, but wear occurs on the cylindrical inner surface of the hole in the needle board, requiring replacement or repair
Solution Approach 1:
The shaft is segmented so that only the clamping section (with larger diameter) contacts and is held under tension in the needle board bore, while the guide section (with smaller diameter) passes through without being clamped. This reduces the contact area and friction, minimizing wear on the needle board while maintaining secure holding of the needle
Solution Approach 2:
The clamping section is designed with a specific diameter (e.g., 1.8mm) and length optimized for secure holding, while the guide section has a smaller diameter (e.g., 1.6mm) that minimizes contact and wear on the needle board. This local differentiation between sections resolves the contradiction between secure holding and extended needle board service life
3Strength
If the felting needle has a stepped reduced section between the shaft and working section, then the necessary stiffness and elasticity are provided for bending and kinking stresses, but the handling becomes more difficult
Solution Approach 1:
The shaft is segmented into the clamping section and guide section, both with cylindrical shapes and uniform cross-sections. This segmentation provides the necessary structural integrity and mechanical properties (stiffness and elasticity) to withstand bending and kinking stresses during operation, while the simple cylindrical geometry of each section maintains ease of handling and manufacturing
Solution Approach 2:
The clamping section has a larger diameter optimized for structural strength and resistance to bending/kinking stresses, while the guide section has a smaller diameter optimized for ease of handling and insertion. This local differentiation provides both the necessary mechanical strength and improved handling characteristics
Data Source
Figure 1~2
Figure 3
AI summary
A felting needle according to the invention has a shaft that adjoins a rear end of the needle in its longitudinal direction. The felting needle has a working section that adjoins a front end. The shaft has a clamping section and a guide section. The guide section is arranged further forward in the longitudinal direction than the clamping section. The guide diameter of the guide section, measured perpendicular to the longitudinal direction, is smaller than the clamping diameter of the clamping section, also measured perpendicular to the longitudinal direction. The felting needle according to the invention is characterized in that the guide diameter is at most 12%, preferably at most 9%, and most preferably at most 6% smaller than the clamping diameter. This allows the felting needle to be inserted more easily into a needle board and protects the needle board during insertion.