Air-jet loom weft yarn detector using optical sensor
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In air-jet looms, determining the optimal jet pressure for auxiliary nozzles to prevent weft yarn strain during weft insertion is challenging due to the inability to directly monitor the state of the weft yarn in the warp shed, especially in continuous warp constructions like satin weaving, where visual checks with a stroboscope are difficult.
Innovation Solution
An air-jet loom equipped with an optical sensor positioned near the reed passage to detect the state of the weft yarn using polarized light, converting the yarn's state into pulse signals that indicate whether the yarn is undulating or strained, allowing for real-time monitoring and display of the straining point before the weft yarn leading end arrival time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If visual checks with a stroboscope are used to monitor weft yarn state, then the state of weft yarn can be observed, but it becomes difficult to check in continuous warp constructions like satin weaving
Solution Approach 1:
The patent replaces the mechanical/optical stroboscope system with an electromagnetic sensing system. The pickup coil detects changes in magnetic flux caused by the motion of weft yarn, converting mechanical motion into electrical signals that can be processed and displayed, thereby eliminating the need for direct visual inspection through the reed passage.
Solution Approach 2:
The patent introduces a magnetic field as an intermediary between the weft yarn and the detection system. The pickup coil detects the magnetic flux changes generated by the moving weft yarn, serving as an indirect measurement method that works effectively even when direct visual observation is impossible, such as in satin weaving with continuous warps.
2Loss of time
If the point in time of straining is determined using TW - TBW changing point, then auxiliary pressure can be set, but the state of weft yarn in the warp shed is not directly monitored
Solution Approach 1:
The patent implements a feedback mechanism where the pickup coil continuously monitors the weft yarn motion state and provides real-time information to the control system. The detection signals are processed to determine the actual point in time of straining, which is then used to adjust the auxiliary nozzle pressure, creating a closed-loop control system that eliminates the need for indirect calculations based on TW - TBW.
Solution Approach 2:
The patent replaces the indirect time-difference calculation method with direct electromagnetic detection of weft yarn motion state. The pickup coil detects the actual straining event through magnetic flux changes, providing direct information about the weft yarn state in the warp shed without relying on alternative indications.
3Stability of the object's composition
If auxiliary pressure is increased to reduce weft yarn undulation, then the point in time of straining occurs earlier, but it becomes harder to optimize the straining timing
Solution Approach 1:
The patent uses the pickup coil detection system to provide real-time feedback on the actual straining timing. This allows the control system to automatically adjust the auxiliary nozzle pressure to achieve optimal straining timing, simplifying the optimization process despite the non-linear relationship between pressure and straining time.
Solution Approach 2:
The detection system enables the system to self-regulate the weft insertion process. By continuously monitoring the weft yarn motion and automatically adjusting the auxiliary pressure based on detected straining events, the system performs self-optimization without requiring complex manual intervention or trial-and-error adjustments.
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 precise monitoring and adjustment of weft yarn strain, facilitating optimal weft insertion by providing clear, numeric data on straining points, reducing the need for visual checks with a stroboscope and improving operational stability in complex weaving conditions.
Implementation Method 1
detect the state of the weft yarn using polarized light
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A weft yarn detector is adapted to be used in an air-jet loom, in which weft insertion of a weft yarn through a reed passage is performed by air jet from a main nozzle and auxiliary nozzles. An optical sensor for detecting the extent of slack of the weft yarn is located in the reed passage at a position close to the main nozzle.