Yarn-Feeding Assembly Stabilizing Tension via Dual Feeders

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Solution Overview

Problem

Existing yarn-feeding systems for textile machines, particularly circular knitting machines, face issues with variable yarn tension due to upstream fluctuations, leading to anomalies and flaws in the finished garment, despite ensuring the exact amount of yarn is delivered.

Innovation Solution

A dual-feeder system where a second feeder upstream stabilizes yarn tension using a control loop and tension sensor, ensuring consistent yarn delivery to the first feeder, which operates in axis with the textile machine, maintaining stable tension by modulating the yarn delivery speed.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If a single feeder operates in axis with the textile machine to deliver the exact amount of yarn required, then the yarn quantity is precisely controlled, but the yarn tension becomes very variable due to upstream fluctuations

Engineering Contradiction:
Improveyarn quantityVSAvoidyarn tension
Core Design Contradiction:
Quantity of substanceVSStability of the object's composition

Solution Approach 1:

The system divides the yarn feeding function into two separate feeders: a first feeder that ensures precise yarn quantity delivery to the machine, and a second upstream feeder that stabilizes yarn tension. This segmentation allows each feeder to specialize in one aspect (quantity or tension) without compromising the other.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The second feeder acts as an intermediary element between the yarn reel and the first feeder. It receives yarn from the reel and delivers it to the first feeder with stabilized tension, thereby mediating the tension fluctuations that would otherwise be transmitted to the machine.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Device complexity

If the yarn is wound on a rotary drum driven mechanically via belt drive, then the structure is simple and inexpensive, but the yarn tension fluctuates due to upstream variations

Engineering Contradiction:
Improvefeeder structureVSAvoidyarn tension
Core Design Contradiction:
Device complexityVSStability of the object's composition

Solution Approach 1:

The system incorporates a control loop that monitors yarn tension and adjusts the operation of the second feeder accordingly. This feedback mechanism allows the system to maintain stable yarn tension despite upstream fluctuations, while the first feeder continues to operate with simple mechanical belt drive for quantity control.

Inventive Principle:
Principle #23Feedback

3Stability of the object's composition

If a dual-feeder system is implemented to stabilize yarn tension, then the yarn tension becomes consistent, but the device complexity increases

Engineering Contradiction:
Improveyarn tensionVSAvoidfeeder system
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The system divides the yarn feeding function into two separate feeders: a first feeder that ensures precise yarn quantity delivery to the machine, and a second upstream feeder that stabilizes yarn tension. This segmentation allows each feeder to specialize in one aspect (quantity or tension) without compromising the other.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The second feeder acts as an intermediary element between the yarn reel and the first feeder. It receives yarn from the reel and delivers it to the first feeder with stabilized tension, thereby mediating the tension fluctuations that would otherwise be transmitted to the machine.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP2754742B1Yarn-feeding assembly for textile machines
Publication Date: 2015.12.09 L G L ELECTRONICS SPA
  • EP2754742B1 patent drawingFigure 1~3
  • EP2754742B1 patent drawingFigure 4

AI summary

A first yarn feeder (14) is provided with a drum (16) which has a plurality of yarn loops (Y) wound thereon and is driven to rotate by a respective motor (20). The motor (20) is electronically connected to a textile machine (12) for rotating at a speed proportional to the yarn-drawing speed of the textile machine and delivering the yarn wound on the drum (16) to the latter. A second feeder (22) is arranged to draw the yarn from a reel (18) and to deliver it to the first feeder (14), with a delivery action which is modulated by a control loop (24). The latter is programmed to stabilize the tension of the yarn unwinding from the second feeder on a predetermined value on the basis of a signal received from a tension sensor (26) operatively coupled to the yarn.