Weaving Reed Centring Zone for Rapier Positioning
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Solution Overview
Problem
Rapier positioning accuracy decreases at higher weaving speeds in rapier weaving machines, limiting the ability to increase fabric production rates due to the need for the weaving reed to be completely stationary during rapier movement, and there is a risk of warp threads jumping, causing fabric defects like stripes.
Innovation Solution
A weaving reed with reed dents featuring recesses and projections that form guide passages and ribs, arranged in centring zones with decreasing clearance towards the transfer point, allowing the rapier to be guided with precision and enabling movement of the weaving reed during rapier insertion, reducing the need for prolonged stationary periods and minimizing warp thread displacement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the weaving reed is configured to guide the rapier with constant clearance throughout, then the rapier positioning is simple and the reed structure is straightforward, but the rapier positioning accuracy decreases at higher weaving speeds and warp threads may jump causing fabric defects
Solution Approach 1:
The patent applies local quality by creating different clearance zones within the reed dent structure. The centring zone has a first clearance value that is larger than the second clearance value in the transfer zone. This localized variation in clearance provides progressive rapier centring while maintaining high positioning accuracy at the transfer point, without requiring the entire reed structure to be complex.
2Productivity
If the weaving reed remains completely stationary during rapier movement, then the rapier can be accurately positioned in the transfer point, but the weaving speed increases are limited due to prolonged stationary periods
Solution Approach 1:
The patent applies dynamics by enabling the weaving reed to move during rapier insertion while maintaining accurate positioning. The variable clearance structure (larger in centring zone, smaller in transfer zone) allows the rapier to be guided accurately even when the reed is in motion, thus increasing weaving speed without sacrificing positioning precision.
3Ease of operation
If the clearance in the centring zone is large, then the rapier can be easily introduced into the shed, but the rapier positioning accuracy at the transfer point deteriorates
Solution Approach 1:
The patent applies parameter changes by varying the clearance dimension along the rapier path. The clearance is larger in the centring zone (first clearance value) to facilitate easy rapier introduction, and smaller in the transfer zone (second clearance value) to ensure high positioning accuracy. This gradual parameter change optimizes both ease of operation and positioning precision.
Data Source
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AI summary
Weaving reed (1) for a rapier weaving machine, comprising several reed dents (2), each of which comprises a recess (3) and/or a projection (4), wherein the recesses (3)/projections (4) of these reed dents (2) form a guide passage (5)/guide rib, wherein the guide passage (5) and/or the guide rib are provided for guiding a rapier (6) with a clearance, wherein at least some of said reed dents (2) are arranged in a centring zone (7) which is situated between an end (10) of the weaving reed (1) and a transfer point (12) and wherein the clearance in this centring zone (7) decreases towards the transfer point (12) of the weaving reed (1).