Card Wire Tooth Design for High Density and Strength
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Solution Overview
Problem
Existing card wires face limitations in achieving high fiber retention and strength while maintaining fatigue resistance, particularly at low tooth pitches, which restricts the number of points per square inch that can be achieved on a carding machine roller.
Innovation Solution
The card wire design features an elongated rib portion with teeth that have a front portion comprising multiple sections, including a straight part and a curved segment, optimized for strength and fatigue resistance, allowing for a higher number of points per square inch with improved fiber retention and recycling capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the pitch between teeth is reduced to increase points per square inch, then the number of points per square inch increases, but the strength and fatigue resistance of the teeth deteriorate
Solution Approach 1:
The tooth front portion is segmented into multiple distinct sections (first section at angle of 10-30 degrees, second section with straight part and curved segment, third section), each serving specific functions. This segmentation allows optimization of each section for different requirements - the angled first section for fiber engagement, the straight part for fiber retention, and the curved segment for structural strength, thereby achieving high point density without compromising tooth strength
Solution Approach 2:
Different sections of the tooth front portion are given different geometric properties tailored to local requirements. The first section has a specific angle (10-30 degrees) for optimal fiber engagement, the second section contains a straight part (minimum 0.10mm) for fiber retention and a curved segment (radius at least 0.18mm) for strength, and the third section for transition to the rib portion. This local differentiation enables the tooth to simultaneously achieve high points per square inch, good fiber retention, and adequate strength
2Reliability
If the straight portion length is increased to improve fiber retention, then the fiber retention characteristics improve, but the tooth strength and fatigue resistance deteriorate
Solution Approach 1:
The patent specifies precise parameter ranges for the straight part (minimum length of 0.10mm, angle of 10-30 degrees) and the curved segment (radius of at least 0.18mm). These parameter changes optimize the balance between fiber retention and tooth strength. The straight part provides sufficient length for fiber retention while the curved segment with its minimum radius ensures adequate structural strength and fatigue resistance, resolving the contradiction between these two requirements
3Quantity of substance
If the tooth pitch is reduced to achieve high points per square inch, then the points density increases, but the fiber retention properties deteriorate
Solution Approach 1:
Instead of relying solely on reducing pitch in one dimension, the patent introduces dimensional complexity in the tooth front portion geometry with multiple sections at different angles and curved segments. This dimensional approach allows the straight part (minimum 0.10mm) to provide adequate fiber retention length even when the overall pitch is reduced, thereby maintaining fiber retention properties while achieving high points per square inch through optimized geometry rather than simply smaller pitch
Data Source
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AI summary
A card wire (110) is comprising an elongated rib portion (112) and teeth. The teeth are having a front portion (114) and a back portion (116). The teeth are hanging over towards their front portion (1 14). The front portion (114) and back portion (116) are merging at the tip (118) of the tooth. The front portion (114) comprises at least three sections: a first section (120) extends from the tip (118) of the tooth in the direction of the rib portion (112), a second section extends below the first section (120) in the direction of the rib portion (112) and a third section (126) extends from the end of the second section in the direction of the rib portion (112). The second section comprises a straight part (122) and a curved segment (124), wherein the straight part (122) is having a minimum length of 0.10 mm and the straight part (122) is having an angle between 10 and 30 degrees relative to the length direction of the card wire. The straight part (122) is followed by the curved segment (124) wherein the curved segment (124) is having a radius (R) of at least 0.18 mm.