Open-End Rotor Spinning Thread Fixing Dynamics
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Solution Overview
Problem
The existing methods for fixing a spun thread to an empty tube in open-end rotor spinning machines face challenges with high productivity due to erratic thread handling and misalignment, leading to production interruptions, as the thread take-off speed and rotor acceleration dynamics result in thread length exceeding storage capacity and insecure clamping.
Innovation Solution
The spinning thread is fixed to the empty tube at a speed below the normal operating speed of the spinning rotor, with reduced acceleration of the rotor and yarn take-off, allowing sufficient time for secure laying and accommodating the thread length within known storage devices, while maintaining productivity by adjusting the rotor speed and feed roller speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the spinning rotor operates at high speed to achieve high productivity, then the production output increases, but the thread length produced during threading exceeds storage capacity and causes misalignment
Solution Approach 1:
The patent applies dynamics by making the rotor speed variable rather than constant. The rotor is accelerated to a reduced speed specifically during the threading process, then accelerated to full operating speed after threading is complete. This dynamic speed adjustment allows the system to maintain high productivity overall while ensuring precise thread alignment during the critical threading phase.
Solution Approach 2:
The patent applies preliminary action by performing the threading operation at reduced speed before the rotor reaches full operating speed. This ensures that the thread is properly aligned and secured on the tube plate before the high-speed production phase begins, preventing misalignment issues that would occur if threading were attempted at full speed.
2Productivity
If the thread take-off speed is increased to match high rotor speed, then productivity improves, but the spinning thread cannot be securely clamped between the empty tube and tube plate
Solution Approach 1:
The patent applies dynamics by coordinating the thread take-off speed with the rotor speed. During threading, both the rotor and thread take-off device operate at reduced speeds, allowing secure clamping of the thread. After threading is complete, both speeds are increased to full operating levels, maintaining productivity while ensuring reliable thread fixation during the critical clamping phase.
Solution Approach 2:
The patent applies feedback by using a sensor to detect when the thread has been properly fixed to the tube plate. Based on this feedback signal, the control system adjusts the rotor speed and thread take-off speed accordingly, ensuring that speed increases only occur after secure clamping is confirmed, thus maintaining both reliability and productivity.
3Productivity
If the rotor accelerates rapidly to operating speed after cheese change, then productivity improves, but the thread handling becomes erratic causing production interruptions
Solution Approach 1:
The patent applies dynamics by implementing a two-stage acceleration profile. First, the rotor accelerates to a reduced speed while the thread is being handled and fixed to the tube plate, ensuring stable thread handling. After threading is complete and confirmed by the sensor, the rotor then accelerates to full operating speed, maximizing productivity without causing thread handling issues.
Solution Approach 2:
The patent applies preliminary action by completing the thread fixation process at reduced speed before the rotor reaches full operating speed. This preliminary threading phase ensures that all thread handling operations are completed safely and reliably, preventing production interruptions. Only after this preliminary phase is successfully completed does the rotor accelerate to full speed for high-productivity operation.
Data Source
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AI summary
The method involves accelerating a spinning rotor (26) after changing an empty case (10). A fiber band (6) is supplied to the rotor via a feeding roller (25). An auxiliary thread (24) is connected to a spinning thread (7) by a spinning unit. The spinning thread is fixed at the empty case, when the rotor is rotated at spinning rotor rotational speed below operating speed during normal spinning operation. The spinning thread is fixed at the case, when thread withdrawal speed is below preset thread withdrawal speed and rotational speed of the feeding roller during the spinning operation. An independent claim is also included for a workstation for an open-end rotor spinning machine.