Yarn-Unwinding Sensor for Rotary Drum Feeders
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Solution Overview
Problem
Existing yarn-unwinding sensors for storage yarn feeders with rotary drums can only provide relative information about yarn unwound, failing to offer accurate, reliable absolute measurements in both steady and transient states, which affects yarn tension stability and quality.
Innovation Solution
A sensor system using light-emitting and light-receiving diodes, integrated with the drum or motor housing, creates a light connection that varies based on yarn passage, allowing absolute counting of unwound yarn loops regardless of drum rotation speed, with different embodiments optimizing light beam paths and reflection surfaces for effective detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If three or more stationary photoelectric cells are spaced at equal angles about the axis of the drum for detecting the unwinding yarn, then the sensor can detect the unwinding yarn and control the motor to maintain constant yarn amount, but the sensor cannot provide absolute binary information about the amount of yarn unwound, only relative information
Solution Approach 1:
The patent replaces the mechanical photoelectric cell detection system with an optical sensor system that uses a light source and photodetector arranged to detect the passage of yarn loops. The sensor counts each time the yarn passes through the detection point, providing absolute information about the number of loops unwound, rather than only relative information about yarn amount on the drum.
Solution Approach 2:
The patent introduces an optical intermediary (light beam) that interacts with the yarn as it passes. The light source emits light that is interrupted or modulated by the yarn loops, and the photodetector detects these optical changes to generate count signals. This intermediary enables absolute counting of yarn loops by translating mechanical yarn movement into electrical count signals.
2Reliability
If the sensor is arranged at the delivery end of the drum with stationary photoelectric cells, then the system can control motor rotation to maintain constant yarn stock, but the complexity of the sensor system increases with multiple photoelectric cells spaced at equal angles
Solution Approach 1:
The patent extracts the detection function from multiple distributed photoelectric cells and concentrates it into a single optical detection point at the delivery end of the drum. Instead of using three or more cells spaced at equal angles, the invention uses one light source and one photodetector arranged to detect yarn passage, simplifying the sensor system while maintaining control reliability.
Solution Approach 2:
The patent creates a simplified optical copy of the yarn detection process. Rather than physically distributing multiple detection points around the drum, the system uses a single detection point that counts each yarn loop passage, effectively copying the information about yarn unwinding without requiring multiple physical sensors.
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 accurate, reliable absolute measurement of yarn unwound from the drum, stabilizing yarn tension and improving textile production quality by providing precise loop counting.
Implementation Method 1
A sensor (40) comprises light-emitting means and light-receiving means, at least one of which is adapted to be attached to the drum... operatively define a light connection passing through a detection area (30c) which is adapted to be repeteadly engaged by the yarn during its rotary, unwinding motion
Data Source
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AI summary
A yarn feeder is provided with a motorized, yarn-winding rotary drum (12) which is rotatable with respect to a motor-housing (16) and is adapted to have a plurality of yarn loops (Y) wound on itself, which are adapted to be unwound upon request from a downstream machine. A sensor comprises light-emitting means (42) and light-receving means (44), at least one of which is to be fixed to the rotary drum (12), which operatively define a light connection passing through a detection area (30c) of the rotary drum (12) which is adapted to be repeatedly engaged by the yarn during its rotational unwinding movement. The unwinding of yarn from the rotary drum is determined on the basis of the variation of light resulting from the yarn (Y) transiting on the detection area (30c).