Optical Yarn Break Detection Using Position Change in the Sensing Slot
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Solution Overview
Problem
Current yarn break detection methods in textile machines suffer from delays in detecting yarn breaks, leading to inefficient stopping of the workstation and potential winding of broken yarn onto the bobbin, which reduces productivity and quality.
Innovation Solution
A contactless optical detection method that monitors and evaluates the position and diameter of yarn in a sensing slot, allowing for early detection of yarn breaks before the broken end passes through, enabling timely stopping of the workstation by comparing changes in yarn position and diameter to preset limits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If yarn break detection is performed using conventional sensors located downstream, then the detection is simple to implement, but the detection delay is large causing broken yarn to be wound onto the bobbin
Solution Approach 1:
The patent transitions from conventional point-based yarn presence detection to a multi-dimensional approach by using an array of radiation-sensitive elements that detect yarn position across multiple spatial dimensions. This allows simultaneous monitoring of yarn position at multiple locations, enabling early break detection before the broken end reaches the bobbin while maintaining systematic complexity through structured sensor arrangement.
Solution Approach 2:
The sensing slot is divided into multiple segments corresponding to individual radiation-sensitive elements arranged in rows. Each element monitors a specific segment of the yarn path, allowing localized detection of yarn position changes. This segmentation enables precise identification of break location and timing without requiring a single complex sensor, thus reducing detection delay while managing device complexity through modular sensor elements.
2Productivity
If the workstation stopping speed is increased to prevent broken yarn from winding onto the bobbin, then productivity is maintained, but the mechanical stress and wear on braking components increases
Solution Approach 1:
The system performs preliminary detection of yarn breaks using the radiation-sensitive element array before the broken yarn end reaches critical locations. By detecting position changes and yarn diameter variations in advance, the control system can initiate braking actions earlier and more gradually, preventing broken yarn from winding onto the bobbin while allowing the braking system to decelerate over a longer period, thereby reducing mechanical stress and wear.
3Reliability
If additional braking measures are applied to stop the workstation quickly, then broken yarn winding is prevented, but the bobbin with great weight and inertia requires intensive braking
Solution Approach 1:
The radiation-sensitive element array provides preliminary detection of yarn breaks at multiple positions along the yarn path. This early warning system allows the control device to initiate a staged braking sequence before the broken yarn end reaches the bobbin, distributing the braking power requirement over time and reducing the peak power demand compared to emergency stopping of heavy bobbins.
Solution Approach 2:
The system continuously monitors yarn position using the array of radiation-sensitive elements and provides real-time feedback to the control device. This feedback enables dynamic adjustment of braking power based on actual yarn position and break detection, allowing optimized braking profiles that prevent broken yarn winding while minimizing the required braking power through adaptive control rather than constant maximum braking.
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
Enables early detection and timely stopping of the workstation, reducing the likelihood of winding broken yarn and improving productivity by distinguishing between different types of breaks and adjusting subsequent operations accordingly.
Implementation Method 1
shading of the individual radiation sensitive elements by the moving yarn is monitored
Data Source
Figure 1
Figure 2~2a
Figure 2b~2c
AI summary
The invention relates to a method of contactless optical detection of yarn (1) at a workstation of a yarn (1) manufacturing textile machine, in which the yarn (1) moves in a sensing slot (92) between at least one source (90) of radiation and at least one optical sensor means (91) of radiation comprising at least one row of radiation sensitive elements arranged next to each other, whereby shading of the individual radiation sensitive elements by the moving yarn (1) is monitored and the state of the yarn (1) is evaluated on the basis of this monitoring process. The position P of the yarn (1) and/or the time course of the position P of the yarn (1) in the sensing slot (92) is monitored and evaluated, thereby detecting a change ΔP in the position P and/or the time course of the change ΔP in the position P of the yarn (1) corresponding to a yarn (1) break and upon detecting the break before the broken yarn (1) end passes through the sensing slot (92), a signal to stop the workstation is issued. The invention also relates to an optical sensor of yarn and a textile machine for performing the present invention.