Yarn Threading Control for Straight-Winding Prevention
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Solution Overview
Problem
Existing yarn threading apparatuses form straight windings on bobbins, leading to issues like yarn breakage and irregular package shapes due to improper yarn traversal, particularly when the yarn threading member returns to the standby position after releasing from the engagement portion.
Innovation Solution
The yarn threading apparatus includes a control unit that disengages the yarn from the engagement portion before the traverse guide starts its movement, uses a separate member to hold the yarn outside the traversal range, and controls the traverse guide and yarn threading member to avoid contact during the return to the standby position, ensuring even yarn distribution across the bobbin.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the yarn threading member returns to the standby position after releasing the yarn from the engagement portion, then the yarn threading process is completed, but straight windings are formed on the bobbin causing yarn breakage and irregular package shapes
Solution Approach 1:
The traverse guide is moved to a predetermined position (outside the traversal range) before the yarn threading member returns to the standby position. This preliminary positioning ensures that when the yarn is released from the engagement portion, the traverse guide is already in the correct position to catch and traverse the yarn, preventing straight windings from forming on the bobbin.
Solution Approach 2:
The system dynamically coordinates the movement of the yarn threading member and the traverse guide. The control unit adjusts the timing and position of the traverse guide based on the state of the yarn threading member, creating a dynamic interaction that prevents the yarn from being wound straight onto the bobbin while maintaining efficient threading speed.
2Ease of operation
If the yarn is disengaged from the engagement portion at the center of the traversal range, then the yarn threading is simplified, but straight winding occurs obstructing yarn unwinding
Solution Approach 1:
The harmful effect of straight winding is prevented by extracting the yarn from the center traversal range before it can be wound straight onto the bobbin. The traverse guide is positioned outside the normal traversal range to catch the yarn at a location that prevents straight winding formation, while still allowing simple disengagement from the engagement portion.
Solution Approach 2:
The traverse guide acts as an intermediary between the yarn engagement portion and the bobbin. By positioning the traverse guide at a predetermined location outside the traversal range, it intercepts the yarn before it can create straight windings on the bobbin, mediating the yarn path to prevent the harmful effect while maintaining operational simplicity.
3Speed
If the traverse guide starts reciprocal movement immediately after yarn release, then yarn traversal begins promptly, but contact with the returning yarn threading member causes operational issues
Solution Approach 1:
The traverse guide is preliminarily positioned outside the traversal range before the yarn threading member completes its return to the standby position. This preliminary positioning ensures that when the traverse guide starts its reciprocal movement, there is no risk of contact with the yarn threading member, maintaining both prompt yarn traversal and process stability.
Solution Approach 2:
The control unit dynamically coordinates the timing of the traverse guide's reciprocal movement with the position of the yarn threading member. By adjusting the start timing of the reciprocal movement based on the yarn threading member's position, the system ensures prompt yarn traversal while avoiding contact that would compromise operational reliability.
Data Source
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AI summary
A package with a proper shape is obtained while formation of straight winding on a bobbin is prevented when yarn threading onto the bobbin is performed. A yarn threading apparatus 60 includes a yarn holding member 61, a yarn threading arm 62 having a yarn engagement portion 62a, a traverse guide 72, and a control unit 64. The yarn engagement portion 62a is arranged to be engaged with a yarn Y that is held by the yarn holding member 61 while the yarn threading arm 62 is moving from a standby position to a yarn threading position, and when the yarn threading arm 62 is at the yarn threading position, the yarn Y is disengaged from the yarn engagement portion 62a. The control unit 64 controls the traverse guide 72 to move to the outside of a predetermined traveling range M and controls the traverse guide 72 to catch the yarn Y disengaged from the yarn engagement portion 62a, and then controls the traverse guide 72 to perform reciprocal movement within the predetermined traveling range M. When the traverse guide 72 is performing reciprocal movement within the predetermined traveling range M and the yarn Y does not exist on a movement trace of the yarn threading arm 62 between the yarn threading position and the standby position, the control unit 64 moves the yarn threading arm 62 to the standby position.