Elastic Yarn Winding Package Shape Control
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Solution Overview
Problem
Existing yarn winding techniques struggle to prevent ribbon winding while inhibiting bulging, especially with elastic yarns, as they often result in improper unwinding and breakage due to the inherent winding tightening force.
Innovation Solution
A yarn winding machine and method that vary the free length between the contact roller and traverse device during winding, increasing it at the start and reducing it towards the end, while maintaining a constant or varying winding angle, to shape the package cross-section and prevent bulging without altering the critical wind number.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If the winding angle is increased to inhibit bulging, then bulging is reduced, but ribbon winding occurs
Solution Approach 1:
The invention changes the winding angle parameter dynamically during the winding process. Specifically, the winding angle is set to be larger at the initial stage of winding and gradually reduced as winding progresses. This parameter change allows the package end surface to remain flat (preventing bulging) while avoiding the critical condition that causes ribbon winding, thereby maintaining yarn unwinding stability.
2Reliability
If the winding angle is reduced to prevent ribbon winding, then yarn unwinding stability is maintained, but bulging occurs
Solution Approach 1:
The invention applies preliminary action by setting a larger winding angle at the initial stage of winding before the package diameter becomes large. This preliminary configuration of the winding angle prevents bulging from occurring in the first place, eliminating the need to reduce the winding angle later to prevent ribbon winding, thus maintaining both package flatness and yarn unwinding stability throughout the entire winding process.
3Shape
If the free length is increased during winding start, then package cross-section is shaped to prevent bulging, but the risk of yarn breakage increases
Solution Approach 1:
The invention applies dynamics by making the free length variable rather than constant. The free length is increased during the initial stage of winding to shape the package cross-section and prevent bulging, then gradually reduced as winding progresses. This dynamic adjustment ensures that the yarn is not subjected to excessive tension that would cause breakage, while still achieving the desired package shape.
Data Source
Figure 1(A)~1(B)
Figure 2(C)~2(D)
Figure 3
AI summary
The present invention provides a technique to prevent possible ribbon winding regardless of yarn type while inhibiting possible bulging. The winder 1 includes a contact roller 8 configured to come into contact with a package 4 during formation of the package 4, a traverse device 7 located upstream side of the contact roller 8 in the traveling direction of an elastic yarn 2, a free length varying means 9 for enabling the free length FL of the elastic yarn 2 located between the contact roller 8 and the traverse device 7 to be varied during formation of the package 4, and a control section 80 configured to control the free length varying means 9 in such a manner that the free length FL is increased during winding start of the package 4 and then reduced toward winding end.