Yarn Tension Measurement Path for Knitting Machines

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Solution Overview

Problem

Existing tension measuring devices for knitting machines inaccurately represent yarn tension after it passes through the yarn feeding port, leading to potential fabric issues due to abnormal tension, as they measure tension before the yarn enters the port and operate during high-speed yarn supply.

Innovation Solution

A tension measuring device that draws the yarn into a measurement path after it passes through the yarn feeding port, allowing for accurate tension measurement without knitting, using a yarn drawing-in means, measuring means, and display means to adjust tension to a target value, ensuring accurate representation of yarn tension for intarsia and varying fabric amounts.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If tension is measured before the yarn passes through the yarn feeding port, then the measurement can be performed during high-speed yarn supply, but the measured tension does not accurately represent the tension after the yarn feeding port

Engineering Contradiction:
Improveyarn supply speedVSAvoidtension measurement accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The system separates the yarn path into two distinct segments: the original feeding path and a separate measurement path. The yarn is drawn off from the feeding path at a point after the yarn feeding port and guided through the measurement path to the take-up roller. This segmentation allows tension measurement to be performed on a diverted portion of the yarn without interfering with the main high-speed feeding process, thereby achieving both high productivity and accurate measurement representation of post-feeding-port tension

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A measurement path acts as an intermediary between the yarn feeding port and the tension measurement point. This intermediate path includes a measurement guide, measurement roller, and take-up roller that collectively create a controlled environment for accurate tension measurement. The intermediary measurement path allows the system to measure tension that accurately represents the post-feeding-port state while maintaining the high-speed supply capability of the original feeding path

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If tension is measured at a position after the yarn passes through the yarn feeding port, then the measurement accurately represents knitting tension, but the measurement path interferes with the high-speed yarn supply to needles

Engineering Contradiction:
Improvetension measurement accuracyVSAvoidyarn supply speed
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The system divides the yarn flow into two independent streams: the primary feeding path continues uninterrupted at high speed to supply needles, while a secondary measurement path draws off a portion of the yarn after the feeding port for tension measurement. This segmentation eliminates interference between the measurement function and the high-speed supply function, allowing both to operate simultaneously at optimal speeds

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Instead of measuring all yarn through a single path, the system applies partial action by measuring only a portion of the yarn that is drawn off through the measurement path. This partial measurement approach is sufficient to represent the tension characteristics of the main yarn flow without requiring the entire yarn supply to slow down or follow the measurement path, thereby maintaining high productivity while achieving accurate measurement

Inventive Principle:
Principle #16Partial or excessive action

3Adaptability or versatility

If a single tension measuring device is used for multiple knitting machines, then device versatility is improved, but the device must accommodate varying yarn speeds and tension requirements

Engineering Contradiction:
Improvedevice reusabilityVSAvoidspeed adjustment mechanism
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The take-up roller is designed with variable speed capability, allowing it to dynamically adjust its rotation speed to match different yarn supply speeds from various knitting machines. This dynamic speed adjustment enables the same tension measuring device to be adapted to multiple machines with different operational parameters, achieving versatility without requiring complex mechanical modifications to the core measurement mechanism

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes the operational parameters of the take-up roller (specifically its rotation speed) to accommodate different knitting machines. By adjusting this single parameter, the device can adapt to varying yarn supply speeds and tension requirements across multiple machines, achieving high versatility with minimal complexity. The measurement path geometry and other structural parameters remain fixed, simplifying the overall device design

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3567148B1Tension measuring device for knitting machine and tension measuring method
Publication Date: 2021.08.11 SHIMA SEIKI MFG LTD
  • EP3567148B1 patent drawingFigure 1
  • EP3567148B1 patent drawingFigure 2
  • EP3567148B1 patent drawingFigure 3

AI summary

There are provided a tension measuring device for a flat knitting machine and a tension measuring method for the same, with which tension of a yarn can be measured in such a manner that measured tension substantially accurately represents tension of the yarn to be knitted into fabric at a position after the yarn passes through a yarn feeding port so that problems can be prevented from occurring to the fabric due to abnormal tension of the yarn. In a flat knitting machine configured such that a yarn 20 is fed to needles via a feed path 2 with tension being applied to the yarn 20, a yarn drawing-in means 51 draws the yarn 20 being in a ready-for-knitting state, at a position after the yarn 20 passes through a yarn feeding port 153, into a measurement path 24 that is different from the feed path 2 to the needles. Subsequently, a measuring means 52 measures tension of the yarn 20 drawn into the measurement path 24 without performing knitting, and the tension of the yarn 20 measured at a position after the yarn feeding port 153 is displayed on a monitor 53.