Carding Wire Tooth Geometry for Fiber Jamming Reduction

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Solution Overview

Problem

Existing clothing wires for carding machines often experience fiber jamming and clogging due to small tooth pitch relative to tooth depth, leading to undesirable fiber accumulation and reduced carding efficiency.

Innovation Solution

A clothing wire design with a calculated ratio of pitch to tooth depth less than 1.1, featuring a distance between the tooth back and base greater than a quarter of the pitch, and a tooth face angle between 45° and 65°, which reduces fiber jamming by allowing smoother fiber sliding and preventing accumulation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the pitch of teeth is made small relative to tooth depth to increase carding aggressiveness, then the carding effect is improved, but fibers get jammed in the tooth cutout and the clothing becomes clogged

Engineering Contradiction:
Improvecarding effectVSAvoidfiber jamming and clogging
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent changes the geometric parameters of the tooth section by defining specific relationships between pitch (p), tooth depth (h), and the distance (d) from the turning point to the opposite tooth face. By establishing that d > p/4 and p/h < 1.1, the design optimizes the balance between carding aggressiveness and fiber flow, preventing jamming while maintaining effective carding action.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces a curved transition at the tooth base with a defined turning point, replacing sharp angular transitions. This curvature with radius r > p/8 creates a smoother fiber path through the tooth cutout, reducing fiber accumulation and jamming while maintaining the aggressive carding effect of the tooth geometry.

Inventive Principle:
Principle #14Spheroidality (Curvature)

2Productivity

If the tooth face is inclined strongly forward towards the foot section to increase carding effect, then the carding aggressiveness is improved, but the stability of teeth is reduced

Engineering Contradiction:
Improvecarding aggressivenessVSAvoidtooth stability
Core Design Contradiction:
ProductivityVSStability of the object's composition

Solution Approach 1:

The patent applies different inclination angles to different sections of the tooth face. The upper portion has a steeper inclination for aggressive carding, while the lower portion near the base has a more gradual slope for stability. This local differentiation of geometric properties allows the tooth to simultaneously achieve high carding effectiveness and structural stability.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The curved transition at the tooth base with radius r > p/8 provides a smooth connection between the inclined tooth face and the horizontal base. This curvature distributes stress more evenly and prevents stress concentration at sharp corners, thereby enhancing tooth stability while maintaining the aggressive forward inclination of the tooth face.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Data Source

PatentEP3473754B1Card wire
Publication Date: 2021.05.19 GROZ BECKERT KG
  • EP3473754B1 patent drawingFigure 1~2
  • EP3473754B1 patent drawingFigure 3

AI summary

A tooth set wire has successive teeth arranged longitudinally at intervals of a pitch. The teeth are bounded longitudinally on one side by a tooth face and on the other by a tooth back. The tooth face and back of successive teeth merge downwards along the vertical direction of the tooth set wire into a tooth root and upwards to form a tooth cusp. The tooth depth is determined by the greatest distance, along the vertical direction of the tooth set wire, from the tooth cusp to the tooth root. The ratio of pitch to tooth depth is less than 1.1. The tooth set wire is characterized by the fact that the distance, measured perpendicular to a tangent at an inflection point between the tooth back and tooth root, from this inflection point to the opposite tooth face is greater than one-quarter of the pitch.