A weft straightener and a method for straightening a fabric web

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Solution Overview

Problem

Existing weft straighteners fail to adequately correct bow and skew errors in fabric webs, leading to undesirable warping and buckling of yarns, particularly during finishing processes like washing, resulting in suboptimal fabric appearance and strength.

Innovation Solution

A weft straightener comprising a bow drum arrangement and a skew drum arrangement, where the bow drums are rotatably mounted and strategically positioned between fixed drums to reduce yarn curvature, and the skew drums are pivotably mounted to adjust yarn inclination, separating the correction processes to prevent strain profile superposition and minimize warpage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If known weft straighteners with bow drums and skew drums are used to correct yarn errors, then some bow and skew correction is achieved, but the yarns still extend buckled at about one third of the web extension and the fabric warps during finishing processes

Engineering Contradiction:
Improvebow correction and skew correctionVSAvoidfabric warpage and yarn buckling
Core Design Contradiction:
Manufacturing precisionVSStability of the object's composition

Solution Approach 1:

The invention divides the correction process into two separate arrangements: a bow drum arrangement for correcting bow errors and a skew drum arrangement for correcting skew errors. This segmentation prevents the superposition of strain profiles that causes buckling and warpage, allowing each arrangement to optimize its specific correction function without interfering with the other.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention introduces an intermediary arrangement between the bow drums and skew drums that guides the web from the bow drum arrangement to the skew drum arrangement. This intermediary prevents direct interaction between the two correction mechanisms, avoiding strain profile superposition while maintaining the sequential correction process.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Manufacturing precision

If bow drums and skew drums are arranged in known configurations, then the web is conveyed over multiple drums for correction, but the strain profiles superimpose and cause buckling at one third of the web extension

Engineering Contradiction:
Improveyarn straighteningVSAvoidstrain profile superposition and buckling
Core Design Contradiction:
Manufacturing precisionVSObject-generated harmful factors

Solution Approach 1:

The invention extracts the skew drum arrangement from the bow drum arrangement by providing separate support structures and mounting arrangements. This extraction eliminates the harmful superposition of strain profiles while maintaining both correction functions, as each arrangement operates independently with its own strain distribution pattern.

Inventive Principle:
Principle #2Taking out (Extraction)

3Manufacturing precision

If multiple drums are used for comprehensive correction, then both bow and skew errors can be addressed, but the device complexity increases and the fabric may warp during finishing

Engineering Contradiction:
Improvecomprehensive error correctionVSAvoiddrum arrangement complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The invention segments the complex multi-drum system into two independent, simpler arrangements: a bow drum arrangement with its support structure and a skew drum arrangement with its support structure. Each arrangement can be optimized independently, reducing overall complexity while maintaining comprehensive correction capability.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP4001489B1A weft straightener and a method for straightening a fabric web
Publication Date: 2024.03.20 CALIK DENIM TEKSTIL SAN VE TIC AS
  • EP4001489B1 patent drawingFigure 1
  • EP4001489B1 patent drawingFigure 2
  • EP4001489B1 patent drawingFigure 3

AI summary

The invention relates to a bow drum arrangement for a weft straightener for a fabric web manufacturing line, with at least one bow drum and a plurality of fixed drums, wherein the at least one bow drum is located in web running direction in between two of the plurality of fixed drums in that it receives the fabric web from one fixed drum and delivers the fabric web to one fixed drum.