Zero-twist yarn feeding device with dynamic loop buffer control
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Solution Overview
Problem
Existing yarn feeding systems for rapier weaving machines, particularly those handling flat or tape yarns without twist, face limitations in speed due to the low capacity of zero-twist yarn feeding devices, often resulting in entanglement or twisting issues that hinder high-speed weaving.
Innovation Solution
A yarn feeding arrangement that controls the speed of a motor-driven bobbin and loop buffer device based on pre-stored information about the rapier's speed and position, adjusting to maintain constant yarn tension and compensate for rapid speed changes, using a controller to ensure the correct amount of yarn is fed to the weaving machine.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the speed of the weaving machine is increased, then productivity is improved, but the existing zero-twist yarn feeding devices cannot keep up, resulting in entanglement or twisting
Solution Approach 1:
The patent employs dynamic control of the loop buffer device that can adjust its position and speed in real-time according to the weaving machine's operational state. The controller receives feedback about yarn tension and machine speed, continuously adjusting the loop buffer's movement to maintain optimal yarn feeding conditions during high-speed operation, preventing entanglement while maintaining productivity.
Solution Approach 2:
The system incorporates feedback mechanisms where the controller monitors yarn tension, loop buffer position, and weaving machine speed. Based on this feedback, the controller dynamically adjusts the loop buffer device's operation to maintain reliable yarn feeding. The feedback loop ensures that when speed increases, the system automatically compensates to prevent entanglement, resolving the contradiction between productivity and reliability.
2Device complexity
If loops are formed freely without control, then device complexity is reduced, but the yarn will entangle or twist causing machine stoppages
Solution Approach 1:
The loop buffer device serves as an intermediary between the yarn source and the weaving machine. It actively manages loop formation and yarn delivery, preventing entanglement and twisting through controlled movement. This intermediary function resolves the contradiction by providing just enough control to prevent harmful effects while maintaining system simplicity through automated rather than mechanically complex solutions.
Solution Approach 2:
The patent replaces complex mechanical loop control mechanisms with an automated control system that uses sensors and electronic control to manage the loop buffer device. This substitution reduces mechanical complexity while effectively preventing yarn entanglement and twisting through intelligent control algorithms that adjust the loop buffer's operation in real-time.
3Ease of operation
If a movable loop roller is used to form loops, then loop formation is achieved, but the mass of inertia creates tension peaks that limit weaving speed
Solution Approach 1:
The loop buffer device is designed with dynamic characteristics that allow it to respond quickly to changing operational conditions without creating tension peaks. By optimizing the mass and movement characteristics of the loop buffer, the system achieves effective loop formation while minimizing inertial effects that would limit weaving speed, resolving the contradiction between ease of operation and productivity.
Data Source
Figure 1
Figure 2a~2c
Figure 2d~4
AI summary
Described are, among other things,methods and devices for feeding yarn to a weaving machine (10), using a weft yarn feeding arrangement (12) for feeding weft yarn (40) to a weaving machine (10) having at least one rapier (11). The yarn feeding arrangement comprises a motor driven bobbin (13) and a motor driven loop buffer device (16). The yarn feeding arrangement further comprising a controller (32) for controlling the motor of the motor driven bobbin and the motor driven loop buffer device. The controller is adapted to -drive the motor (14) of the motor driven bobbin at a speed to feed an average or essentially an average amount of weft yarn that the weaving machine consumes wherein said essentially average amount of weft yarn deviates less than a pre-set amount from the actual average amount consumed by the weaving machine. -drive the motor of the motor driven loop buffer device based on the difference between the output speed of yarn (40) from the motor driven bobbin and a model of weft yarn insertion speed in the weaving machine and -adjust the drive of the motor of the motor driven loop buffer device based on a signal representing the actual weft yarn tension.