Thread Buffer Leaf Springs for Open-End Spinning Tension Control
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Solution Overview
Problem
Existing mechanical thread stores for open-end spinning machines are not adaptable to varying thread tensions across different types of cross-wound bobbins, struggling to maintain uniform tension during the winding process, especially when transitioning between low-tension dye bobbins and high-tension coarse yarn spools.
Innovation Solution
A mechanical thread store design featuring two leaf spring elements with different spring forces, where a softer first leaf spring element is used for low-tension bobbins and automatically engages a stiffer second leaf spring element when higher tension is reached, ensuring consistent thread tension across a wide range of bobbin types without the need for conversion or adjustment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single leaf spring element is used in the thread store, then the device structure is simple, but it cannot adapt to varying thread tensions across different bobbin types
Solution Approach 1:
The thread store is segmented into multiple leaf spring elements (first and second leaf spring elements) with different spring forces, allowing the system to handle different thread tension requirements separately. Each leaf spring element can be independently engaged based on the specific bobbin type being processed.
Solution Approach 2:
The thread store employs a dynamic configuration where the first and second leaf spring elements can be selectively engaged or disengaged based on the thread tension requirements. The system transitions from a static single-spring design to a dynamic multi-spring system that adapts its configuration in real-time based on operational needs.
2Reliability
If a single leaf spring element with fixed spring force is used, then the manufacturing is simple, but it cannot maintain uniform thread tension across different bobbin types
Solution Approach 1:
Different portions of the thread store system have different spring forces tailored to specific requirements. The first leaf spring element has a lower spring force suitable for low-tension applications (dye bobbins), while the second leaf spring element has a higher spring force for high-tension applications (coarse yarn spools). This local differentiation of spring properties ensures optimal tension control for each specific application.
3Adaptability or versatility
If the thread store is designed for high thread tension, then it can handle coarse yarn spools, but it cannot properly control low thread tension for dye bobbins
Solution Approach 1:
The thread store is designed with multi-functionality to handle both low-tension dye bobbins and high-tension coarse yarn spools using the same basic device structure. By incorporating multiple leaf spring elements with different spring forces that can be selectively engaged, the system achieves universal applicability across different bobbin types without requiring separate devices for each application.
4Ease of operation
If a pivoting lever with proportional adjustment is used, then the thread quantity can be adjusted, but the control device becomes complex and requires precise measurement systems
Solution Approach 1:
The thread store employs self-service mechanisms where the leaf spring elements automatically engage or disengage based on the thread tension requirements without requiring complex external control systems. The system uses the physical properties of the springs and the geometry of the pivoting lever to automatically adjust thread quantity, eliminating the need for sophisticated sensors and control algorithms.
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
This design allows for seamless adaptation to both low and high thread tension bobbins, maintaining thread tension between 2-3 cN for dye bobbins and over 100 cN for coarse yarns, ensuring consistent and uniform tension throughout the winding process.
Implementation Method 1
Mechanical yarn stores, which are used when winding cylindrical cross-wound bobbins and compensate for the changes in yarn winding speed caused by the yarn traversing by means of a leaf spring element
Data Source
Figure 1
Figure 2
AI summary
The device (2) has laminated spring elements (32, 34) arranged at a holder that is supported in a swivelable manner. A yarn deflection roller (36) is arranged at the spring elements. One of the spring elements (32) support the yarn deflection roller, and the other spring element (34) is provided at a distance to the former spring element. The former spring element exhibits reduced spring force than that of the latter spring element. The former spring element exhibits thickness that ranges from 0.2 to 0.3 mm. The latter spring elements exhibit thickness of 0.4 mm.