Yarn Tension Control Device with Dynamic Cam Actuation
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Solution Overview
Problem
Existing yarn tension control devices in textile machines apply constant tension to yarns, leading to unnecessary load on the yarn, especially during non-knotting operations.
Innovation Solution
A yarn tension control device comprising a motor, a cam, yarn guides, a spring, and an arm that rocks to adjust yarn tension, allowing for controlled tension application and release based on the yarn's state during knotting operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a constant tension device is used to apply tension to the yarn, then the yarn tension is maintained during knotting operations, but unnecessary load is applied to the yarn during non-knotting operations
Solution Approach 1:
The patent applies a dynamically adjustable tensioning arm that can change its position between a first position (applying tension) and a second position (reducing tension). The arm is actuated by a actuator that responds to control signals indicating whether the yarn is being knotted, allowing the system to adapt the tension level to the current operational state, thereby eliminating unnecessary load during non-knotting operations while maintaining reliability during knotting.
Solution Approach 2:
The system changes the tension parameter by moving the tensioning arm between different positions. When the yarn is being knotted, the arm is positioned to apply appropriate tension; when knotting is not occurring, the arm moves to a position that reduces or eliminates tension, thus adjusting the physical parameter of yarn load according to operational requirements.
2Device complexity
If a spring-based tensioning device is used, then simple constant tension is applied, but the tension cannot be adjusted based on operational state
Solution Approach 1:
The patent transforms a static spring-based tensioning system into a dynamic one by adding an actuator that can move the tensioning arm between predefined positions. This maintains the simplicity of the spring mechanism while adding the capability to adjust tension levels based on whether knotting operations are active, achieving adaptability without significantly increasing overall system complexity.
Solution Approach 2:
The tensioning system is segmented into a passive spring component and an active actuation component. The spring provides the base tensioning function, while the actuator provides discrete position control. This segmentation allows the system to maintain mechanical simplicity while gaining programmable adaptability through the addition of a relatively simple actuation mechanism.
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
The device effectively controls yarn tension, reducing unnecessary load during non-knotting operations and ensuring proper tension during knotting, thereby improving yarn management in textile machines.
Implementation Method 1
a spring that generates a biasing force
Implementation Method 2
a cam configured to be rotatable by the driving force of the motor
Data Source
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AI summary
A yarn tension control device, a knotter device, and a flat knitting machine capable of controlling tension applied to a yarn are provided. A motor (31) that generates a driving force, a cam (33) configured to be rotatable by the driving force of the motor (31), a pair of yarn guides (37A, 37B) that guides a yarn (A) to a predetermined position, a kick spring (39) that generates a biasing force, and an arm that is freely-rocked and supported along a virtual plane passing between the pair of yarn guides (37A, 37B) are provided, and the arm includes an insertion hole (38a) through which the yarn (A) guided by the pair of yarn guides (37A, 37B) is inserted and a pin (38b) on which the cam (33) can act, is biased by the kick spring (39) in a direction of applying a tension to the yarn (A), and rocks in a direction away from the pair of yarn guides (37A, 37B) with reference to a position where the biasing force of the kick spring (39) and the tension of the yarn (A) are balanced by an action of the cam (33) on the pin (38b) to increase the tension applied to the yarn (A).