Non-contact Yarn Quality Sensor for Loom Weft Monitoring
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Solution Overview
Problem
Existing weaving machines face challenges in efficiently monitoring yarn defects, such as fluff and knots, particularly in the weft threads, due to the complexity of mechanical deflection required by previous sensor principles, which are not suitable for online measurement during sudden acceleration.
Innovation Solution
A non-contact yarn quality sensor is arranged between the weft thread feed and the shed, allowing for the detection of defects like fluff and other quality issues without interfering with the yarn, using a light barrier or reflective optical sensor to measure parameters like diameter or cross-section, enabling real-time monitoring of all weft threads with a single sensor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fluff monitor is used to detect yarn defects, then yarn quality can be monitored, but the mechanical deflection required by previous sensor principles makes the system complex and unsuitable for on-line measurement during sudden acceleration
Solution Approach 1:
The patent replaces mechanical deflection mechanisms with optical sensing principles. A light source and sensor are positioned to detect changes in light transmission through the yarn, allowing quality monitoring without mechanical contact or deflection. This resolves the contradiction by eliminating complex mechanical components while maintaining reliable defect detection capability.
Solution Approach 2:
The patent introduces light as an intermediary medium to detect yarn defects. Instead of directly mechanically interacting with the yarn, the system uses light transmission properties as a mediator to identify fluff and other defects. This approach simplifies the overall system by replacing mechanical deflection mechanisms with a simpler optical measurement system.
2Measurement precision
If multiple yarn quality sensors are fitted in front of each eyelet arm, then each weft thread can be monitored individually, but the device complexity and cost increase significantly
Solution Approach 1:
The patent makes a single yarn quality sensor serve multiple functions by positioning it to monitor all weft threads sequentially as they pass through the sensor zone. The sensor detects defects in different weft threads at different times during the weaving cycle, eliminating the need for multiple separate sensors. This resolves the contradiction by reducing device complexity while maintaining comprehensive monitoring capability.
Solution Approach 2:
The patent merges the functionality of multiple individual sensors into a single sensor that can detect defects in all weft threads. By strategically positioning one sensor and utilizing the sequential nature of weft thread insertion, the system combines what would traditionally require multiple separate measurement devices into a single unified sensor system.
3Measurement precision
If contact sensors are used to detect yarn defects, then measurement can be performed, but the sensor itself may contribute to yarn quality impairment through fiber accumulation
Solution Approach 1:
The patent replaces contact-based mechanical sensors with a non-contact optical sensor system. Light transmission through the yarn is measured to detect defects such as fluff and knots, eliminating direct physical contact between the sensor and yarn. This resolves the contradiction by preventing fiber accumulation on the sensor while maintaining accurate defect detection capability.
Solution Approach 2:
The patent uses light as an intermediary to detect yarn defects without direct sensor contact. The optical field serves as a mediator that can penetrate and interact with the yarn non-contactedly, allowing quality measurement while preventing the sensor from becoming contaminated with fibers. This eliminates the harmful effect of fiber accumulation on sensor performance.
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 solution allows for effective, non-invasive monitoring of yarn quality, preventing defects from entering the fabric and enabling immediate action or quality evaluation, enhancing the reliability and efficiency of the weaving process.
Implementation Method 1
using a light barrier or reflective optical sensor to measure parameters like diameter or cross-section
Implementation Method 2
using a light barrier or reflective optical sensor to measure parameters like diameter or cross-section
Data Source
Figure 1
AI summary
The loom has a non-contact yarn quality sensor (12) in the passage of the weft yarn at the transfer zone (8) between the weft guide (9) and the shed (1). The sensor registers the yarn diameter or cross section and detects the presence of any lint. The sensor forms a light barrier with a measurement zone (14) at a frame (13) at right angles to the weft movement line (Y) and an opening (15) across the weft.