Weft Sensor Placement for Air Jet Loom Yarn Monitoring

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Solution Overview

Problem

High-speed air jet looms face challenges in precisely monitoring the weft yarn traveling condition due to the high impact speed of the yarn, which can lead to breakage, and existing systems struggle to detect changes in yarn type and air injection pressure, making precise monitoring difficult.

Innovation Solution

A method involving a weft measuring and storing device with a storage drum, a weft stop pin, a balloon sensor for yarn release detection, a weft insertion nozzle, sub-nozzles, a brake, and a weft sensor positioned upstream of the brake to detect the weft yarn's passage timing and release timing, allowing for precise monitoring of the weft traveling condition by measuring the time difference between these events.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a brake is applied to the weft yarn before the end of weft insertion to relieve impact, then yarn breakage is prevented, but the ability to detect changes in yarn traveling condition deteriorates because detection is made after braking

Engineering Contradiction:

Improveyarn breakage preventionVSAvoidweft traveling condition detection precision

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

The patent applies preliminary action by detecting the weft yarn's passage timing through the reed before the brake is applied. The detection is performed at a timing earlier than the conventional post-braking detection, allowing the system to capture the yarn's traveling condition during the acceleration and steady-state phases when changes are most apparent, while still maintaining the brake's protective function.

Inventive Principle:

Principle #10Preliminary action

2Productivity

If high-speed operation at 1000 rpm or higher is implemented to increase productivity, then output is improved, but the weft yarn is subjected to great shock of impact that may cause breakage

Engineering Contradiction:

Improveweaving speedVSAvoidyarn breakage resistance

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent implements feedback by using the detected weft passage timing to calculate the time difference between weft release and weft passage, which provides information about the yarn's traveling condition. This feedback mechanism allows the system to monitor yarn behavior at high speeds and adjust operations to prevent breakage while maintaining high productivity.

Inventive Principle:

Principle #23Feedback

3Manufacturing precision

If the time difference between weft release time and weft arrival time is decreased to minimize loosening, then weft insertion quality is improved, but air consumption increases

Engineering Contradiction:

Improveweft insertion qualityVSAvoidair consumption

Core Design Contradiction:

Manufacturing precisionVSLoss of energy

Solution Approach 1:

The patent applies dynamics by making the target time difference adjustable rather than fixed. The control device can change the target time difference based on the detected weft traveling condition, allowing optimization of the balance between weft insertion quality and air consumption. This dynamic adjustment enables the system to adapt to different yarn types and operating conditions.

Inventive Principle:

Principle #15Dynamics

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 approach enables precise monitoring of the weft yarn traveling condition, allowing for better control of air injection pressure and operation timing, reducing yarn breakage and improving the balance between weft release and conveyance performance, thus enhancing the overall weaving process.

Implementation Method 1

a balloon sensor that detects the release of the weft yarn

Methodology Applied

Scientific EffectBalloon sensor detection:

Implementation Method 2

a weft sensor that is disposed within a width of cloth to be woven by the air jet loom so as to detect the weft yarn

Methodology Applied

Scientific EffectWeft sensor detection:

Implementation Method 3

conveyed throughout the weaving width of the air jet loom by a plurality of sub-nozzles

Methodology Applied

Scientific EffectAir jet propulsion: Jet

Implementation Method 4

The air injection pressure of the main nozzle is controlled so that the weft release time detected by the weft release sensor coincides with a target time

Methodology Applied

Scientific EffectAir pressure application: Pressure Gradient

Implementation Method 5

a brake that applies braking to the weft yarn before the weft insertion ends

Methodology Applied

Scientific EffectBraking force application: Friction

Data Source

PatentEP3144422B1Method for monitoring weft traveling condition in air jet loom

Publication Date: 2018.10.17 TOYOTA INDUSTRIES CORP

Figure 1A~1B
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AI summary

There is provided a method for monitoring weft traveling condition in an air jet loom that includes a weft measuring and storing device having a drum, a weft stop pin, and a balloon sensor that detects the release of the weft yarn. The air jet loom further includes a weft insertion nozzle, a plurality of sub-nozzles, a brake, and a weft sensor that is disposed within a width of cloth. The weft sensor is disposed upstream of a position of leading end of the weft yarn corresponding to a brake timing of the brake in weft insertion direction. The weft traveling condition is monitored by grasping a time difference between a weft passage timing given by a weft detection signal generated by the weft sensor and a weft release timing given by a weft release signal generated by the balloon sensor.