Warp Knitting Roller Vibration Damping for Wider High-Speed Operation

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Solution Overview

Problem

Warp knitting machines face challenges in combining higher working speeds and larger working widths due to increased vibration issues, which affect the quality of the knitted fabric and make maintenance difficult, as the rollers become more sensitive to vibrations.

Innovation Solution

A vibration absorber arrangement is integrated into the rollers, comprising a mass arrangement connected via a spring to the roller tube, using passive, active, hybrid, or adaptive vibration absorbers to absorb vibrations, with a design that optimizes damping without additional installation space and maintains homogeneous mass distribution for effective vibration cancellation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the working width and operating speed of the warp knitting machine are increased, then productivity is improved, but vibrations increase and fabric quality deteriorates

Engineering Contradiction:
ImproveproductivityVSAvoidvibrations
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent converts the harmful vibrations into beneficial damping forces by installing vibration damper assemblies within the roller cavities. These dampers contain mass elements connected via springs that resonate at frequencies matching the roller vibrations, thereby absorbing and dissipating the harmful vibrational energy while the machine operates at high speed and width for improved productivity

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

2Object-affected harmful factors

If the mass or rigidity of rollers is increased to reduce vibrations, then vibration damping is improved, but maintenance complexity increases

Engineering Contradiction:
Improvevibration dampingVSAvoidmaintenance complexity
Core Design Contradiction:
Object-affected harmful factorsVSEase of repair

Solution Approach 1:

The patent segments the vibration damping function from the roller structure itself by installing separate, modular vibration damper assemblies within the roller cavities. This allows the dampers to be independently accessed, removed, and replaced without removing the entire roller or fabric take-up unit, thereby maintaining effective vibration damping while significantly improving maintenance ease

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The vibration damper assemblies are nested within the hollow cavities of the rollers, utilizing the existing internal space. This nesting approach allows the addition of vibration damping functionality without increasing the external dimensions or mass of the rollers, avoiding the maintenance complications associated with heavier or more rigid roller designs

Inventive Principle:
Principle #7Nested doll (Nesting)

3Device complexity

If passive vibration dampers are used, then device complexity is reduced, but adaptability to different vibration frequencies decreases

Engineering Contradiction:
Improvedevice complexityVSAvoidfrequency adaptability
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent employs multiple passive vibration damper assemblies, each with differently tuned spring constants and mass elements designed to resonate at specific vibration frequencies. By selecting and installing dampers with appropriate parameters for different frequency ranges, the system achieves broad frequency adaptability while maintaining the simplicity of passive mechanical components without requiring external power or control systems

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

The vibration absorber arrangement effectively reduces vibration amplitudes at nominal speeds, allowing for higher productivity and quality knitted fabrics while enabling larger working widths without compromising maintenance accessibility.

Implementation Method 1

the vibration of the roller tube is introduced directly into the vibration damper. The vibration is then transmitted via the spring arrangement to the mass assembly, which in turn vibrates, approximately in opposite phase to the excitation vibration

Methodology Applied
Scientific EffectVibration: Vibration

Implementation Method 2

the vibration damper comprises a mass assembly connected to the roller tube via a spring arrangement

Methodology Applied
Scientific EffectSpring: Spring

Implementation Method 3

the mass assembly, which in turn vibrates, approximately in opposite phase to the excitation vibration, thereby extracting energy from the vibration of the roller tube

Methodology Applied
Scientific EffectVibration damping: Damping

Implementation Method 4

Two new resonant frequencies are created, but these have a smaller amplitude

Methodology Applied
Scientific EffectResonance: Resonance

Data Source

PatentEP3957788B1Warp knitting loom
Publication Date: 2024.07.03 KARL MAYER STOLL R&D GMBH
  • EP3957788B1 patent drawingFigure 1~3

AI summary

A warp knitting machine (1) with a knitting area (2) and a fabric take-off (3) is specified, which includes at least one roller (5-7). The aim is to provide a warp knitting machine with high productivity. For this purpose, the roller (5-7) is provided with a vibration damper arrangement.