Weft Threader with Curved Eyelet Reducing Warp Wear
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Solution Overview
Problem
Existing heald designs cause excessive wear on warp threads due to high stress and acceleration, leading to potential damage during the weaving process.
Innovation Solution
A heald design featuring a thread eyelet with two thread contact surfaces that are connected by a central curved section, providing a large contact surface area and smooth transitions without edges, which reduces stress on the warp thread and heald.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the thread eyelet is formed by punching an opening in the metal strip creating two webs, then the heald structure is simple and easy to manufacture, but edges are formed in the area of the thread eyelet which lead to severe wear of the warp thread
Solution Approach 1:
The patent applies curvature by replacing the sharp edges formed by punching with rounded surfaces. The thread contact surfaces are designed with curved contours that smoothly guide the warp thread, eliminating the harmful edges that cause wear. This is achieved by forming the thread eyelet with rounded edges and smooth transition zones instead of sharp angular cuts.
Solution Approach 2:
The patent changes the geometric parameters of the thread eyelet area by increasing the radius of curvature at the edges and optimizing the shape of the thread contact surfaces. These parameter changes transform the sharp-edged geometry into a smooth, rounded geometry that reduces stress concentration and prevents warp thread damage while maintaining manufacturing feasibility.
2Volume of moving object
If the two thread contact surfaces are thin like webs, then the heald is thinner and more compact, but the contact surface for the warp thread is very small leading to high stress concentration
Solution Approach 1:
The patent resolves this contradiction by extending the thread contact surfaces not only in the thickness direction but also in the longitudinal direction along the warp thread path. This dimensional extension creates a larger contact area that distributes stress effectively, while the overall heald thickness remains compact due to the optimized surface geometry and curvature design.
3Stress or pressure
If the thread contact surfaces are large and extended, then the stress on the warp thread is distributed better, but the heald becomes relatively thick in the area of the thread eye
Solution Approach 1:
The curved design of the thread contact surfaces allows for an optimized distribution of material thickness. The curvature enables the contact surfaces to extend in area while maintaining a compact overall thickness by utilizing three-dimensional surface geometry rather than simple planar extensions.
Data Source
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AI summary
The invention relates to a weft threader (10) for a weaving shaft (14). The weft threader (10) has a heddle body (11), which is preferably made of plastic by injection molding. A thread eye (15) of the weft threader (10) serves to guide a warp thread in a warp thread direction (F). Viewed in the longitudinal direction (L) of the heddle body (11), the thread eye (15) is bounded by two opposing thread support surfaces (25). The two thread support surfaces (25) are identically designed. Each thread support surface (25) has a first flat surface section (42) and a second flat surface section (43). Viewed in the warp thread direction (F), the inclination of the two surface sections (42, 43) is constant and preferably of different magnitudes. The inclination is measured relative to a reference plane (E), which is horizontally oriented in the operating position of the weft threader (10).The two surface sections (42, 43) are connected seamlessly and without edges by an intermediate central curvature section (44), which has a convex shape when viewed from the thread support surface (25).