Warp Knitting Thread Tension Compensation via Natural Frequency Control

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Solution Overview

Problem

Existing warp knitting machines face challenges in maintaining consistent thread tension compensation, leading to reduced quality of knitted fabrics due to the need for manual adjustment of thread tension compensation devices at each machine setting, which is time-consuming and prone to errors, especially when switching between different fabrics or machine speeds.

Innovation Solution

A warp knitting machine equipped with an externally actuated adjusting device connected to a control system that automatically adjusts the natural frequency of the thread tension compensation device, allowing for automated optimization of thread tension distribution without manual intervention, using a spring arrangement and sensors to detect machine speed and vibrations for precise adjustments.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If manual adjustment of thread tension compensation device is performed at each machine setting, then thread tension compensation can be optimized for specific conditions, but adjustment time increases and errors are more likely to occur

Engineering Contradiction:
Improvethread tension compensation precisionVSAvoidadjustment time
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The control device automatically adjusts the thread tension compensation device based on machine speed and vibration data, eliminating the need for manual intervention. The system self-regulates by detecting operational parameters and making real-time adjustments to the natural frequency of the compensation device, thereby reducing both adjustment time and potential for human error.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

Vibration sensors continuously monitor the machine's vibration levels and feed this information back to the control device. The control device processes this feedback and automatically adjusts the thread tension compensation device accordingly, creating a closed-loop system that maintains optimal thread tension without manual intervention.

Inventive Principle:
Principle #23Feedback

2Adaptability or versatility

If thread tension compensation device is manually adjusted for each new job, then optimal compensation can be achieved for different fabrics and speeds, but worker experience becomes critical and setup complexity increases

Engineering Contradiction:
Improveadaptability to different fabrics and speedsVSAvoidease of setup
Core Design Contradiction:
Adaptability or versatilityVSEase of operation

Solution Approach 1:

The system automatically adapts to different fabrics and speeds by using vibration sensors to detect operational conditions and the control device to adjust the thread tension compensation device accordingly. This eliminates the need for workers to manually adjust settings for each new job, making the machine equally adaptable to different conditions without increasing setup complexity.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent replaces the manual mechanical adjustment system with an automated control system that uses sensors and actuators. This substitution eliminates the need for worker intervention while maintaining or improving adaptability to different fabrics and speeds, thereby simplifying the setup process.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Productivity

If natural frequency of thread tension compensation device matches machine excitation frequency, then device responds to thread consumption changes, but oscillation occurs and quality decreases

Engineering Contradiction:
Improveresponse to thread consumptionVSAvoidproduction stability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The control device dynamically adjusts the natural frequency of the thread tension compensation device based on real-time vibration data from the machine. By continuously adapting the natural frequency to match or avoid excitation frequencies, the system maintains optimal response to thread consumption changes while preventing oscillation and ensuring production stability.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes the physical parameters of the thread tension compensation device, specifically its natural frequency, in response to detected vibration patterns. This parameter adjustment allows the device to optimize its response to thread consumption while avoiding resonant conditions that would cause oscillation and quality issues.

Inventive Principle:
Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This solution enables consistent thread tension compensation across the machine width, reducing the risk of oscillation and improving fabric quality by automating the adjustment of natural frequency, thus minimizing the need for manual adjustments and ensuring optimal thread tension distribution during production.

Implementation Method 1

A relatively simple embodiment of a thread tension compensation device has a spring arrangement. By deforming the springs of the spring arrangement, the changing length of the threads between the thread delivery area and the knitting area, which results from stitch formation, is compensated for.

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

the actuating device has an actuating drive which is connected to a control device which controls the actuating drive... With this thread tension compensation device, the different thread consumption during stitch formation is compensated.

Methodology Applied
Scientific EffectMechanical Force: Mechanical Force

Data Source

PatentEP2565310B1Warp knitting machine
Publication Date: 2014.03.26 KARL MAYER TEXTILMASCHFAB GMBH
  • EP2565310B1 patent drawingFigure 1
  • EP2565310B1 patent drawingFigure 2

AI summary

The knitting machine (1) has a yarn feeding portion (2), an active region (3), and a thread tension compensating device (11) connected to the yarn feeding portion and the active region. The tension compensating device can be actuated from the outside through a control device (17) with which a natural frequency of the tension compensating device is varied. The tension compensating device is comprised of a spring arrangement which comprises several springs (14) distributed over the working width of knitting machine. The control device acts simultaneously on all the springs.