Elastic Yarn Draft Control Under Critical Tension

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Solution Overview

Problem

Existing tension control devices for elastic yarns in textile production do not adequately address the need to maximize draft and minimize downtime due to tension spikes, which are critical for producing consistent and efficient textile products like hygiene articles and diapers.

Innovation Solution

A method that involves selecting a draft for elastic yarn, managing its elongation by adjusting the speed ratio of the yarn processing equipment to the driven roll, measuring tension, and triggering an alarm to adjust the draft when critical levels are reached to prevent yarn breaks and maintain consistent tension.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If tension control devices are used to maintain consistent yarn tension, then yarn tension consistency is improved, but draft maximization and productivity are limited

Engineering Contradiction:
Improveyarn tension consistencyVSAvoiddraft maximization
Core Design Contradiction:
Stability of the object's compositionVSProductivity

Solution Approach 1:

The system dynamically adjusts the draft ratio between the driven roll and yarn processing equipment based on real-time tension feedback. The draft is not fixed but varies automatically to maintain optimal tension while maximizing productivity, allowing the system to adapt between consistent tension mode and maximum draft mode as needed

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention changes the draft parameter dynamically based on tension conditions. When tension is within acceptable ranges, the system increases draft to maximize productivity. When tension approaches critical levels, the system reduces draft to prevent yarn breaks, thus optimizing both productivity and yarn tension consistency

Inventive Principle:
Principle #35Parameter changes

2Productivity

If draft of elastic yarn is increased to maximize yield, then productivity is improved, but risk of yarn breaks due to tension spikes increases

Engineering Contradiction:
Improveyarn utilizationVSAvoidyarn break prevention
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The system uses real-time tension feedback from sensors monitoring the elastic yarn to automatically adjust the draft ratio. When tension approaches critical levels, the feedback signal triggers a reduction in draft to prevent yarn breaks. This closed-loop control enables the system to operate at high draft levels safely, maximizing productivity while maintaining reliability

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system prepares for potential yarn breaks by monitoring tension trends and proactively adjusting draft before critical failure occurs. The alarm system and automatic draft reduction act as preventive measures, cushioning against the harmful effect of yarn breaks before they happen

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

3Stability of the object's composition

If single loop or double loop tension control systems are used, then yarn tension stability is improved, but device complexity increases

Engineering Contradiction:
Improvetension controlVSAvoidcontrol system complexity
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The invention extracts the tension control function from complex multi-loop systems and implements it through a simplified draft control mechanism. By controlling the draft ratio between the driven roll and processing equipment, the system achieves effective tension control without requiring elaborate tension control devices, thus reducing device complexity while maintaining stability

Inventive Principle:
Principle #2Taking out (Extraction)

Data Source

PatentEP2981642B1Process for draft control on feeding of elastic yarn
Publication Date: 2019.03.06 INVISTA TECHNOLOGIES SARL(CH)
  • EP2981642B1 patent drawingFigure 1

AI summary

A method for unwinding yarn is provided that allows for maximizing the draft of the yarn, while monitoring tension. The method includes providing a yarn package including elastic yarn; choosing a selected draft for said elastic yarn; unwinding the elastic yarn from the yarn package from a driven roll to yarn processing equipment at the selected draft which is determined by a ratio of a speed of the yarn at the yarn processing equipment to a speed of the driven roll; measuring tension in the elastic yarn; and providing an alarm when said tension reaches a critical level.