Motorized Yarn Feeder with Selectable Control Modes
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Solution Overview
Problem
Existing yarn feeders struggle to accurately provide the correct amount of yarn to textile machines, leading to defects in garments due to variations in yarn tension and length caused by friction and errors in speed control.
Innovation Solution
A motorized positive yarn feeder with a control unit that selectively operates in position control or tension control modes based on the type of knitting, using sensors and programmable logic to adjust the reel position or speed to maintain precise yarn delivery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If feeders operate under controlled tension mode, then yarn tension is stabilized at a fixed value, but the amount of yarn supplied becomes inaccurate due to friction variations
Solution Approach 1:
The system dynamically switches between two operating modes (controlled tension and controlled speed) depending on the knitting type being produced. For Jacquard knits, controlled tension mode is used to handle variable yarn pickup, while for Jersey knits, controlled speed mode is used to ensure precise yarn length delivery, thus resolving the contradiction between tension stability and length accuracy
Solution Approach 2:
The control unit changes the operating parameter from tension control to speed control based on the knitting pattern requirements. This parameter change allows the system to optimize for either tension stability or length precision depending on the specific application, eliminating the fixed limitation of single-mode operation
2Speed
If feeders operate under controlled speed mode, then yarn feeding speed is stabilized, but position errors compound over time leading to major length errors
Solution Approach 1:
The system dynamically selects controlled speed mode only for Jersey knits where uniform speed is critical, while switching to controlled tension mode for Jacquard knits where variable speed is acceptable. This dynamic selection prevents prolonged operation in controlled speed mode that would lead to error compounding
Solution Approach 2:
The control unit continuously monitors the knitting type and provides feedback to adjust the operating mode accordingly. This feedback mechanism ensures that controlled speed mode is only activated when necessary, preventing error accumulation by switching to controlled tension mode when precision is less critical
3Manufacturing precision
If mechanical actuation with belt transmission is used, then yarn length accuracy is improved, but versatility and adjustment possibilities are reduced
Solution Approach 1:
The patent replaces the mechanical belt transmission system with an electronically controlled motorized reel system. The motorized reel can be precisely controlled through electronic means to achieve accurate yarn length delivery while allowing easy adjustment of operating parameters through software, thus eliminating the need for physical pulley changes and improving versatility
Solution Approach 2:
The system uses electronic parameter adjustment instead of mechanical component changes. Transmission ratios and speed settings can be modified through software parameters rather than physically replacing pulleys, providing both the precision of mechanical systems and the flexibility of electronic control
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 feeder ensures precise and reliable yarn supply, matching the yarn length to the machine's requirements, reducing defects and improving garment quality, while also offering versatility in operating modes and ease of setup.
Implementation Method 1
the yarn tension is monitored continuously by a tension sensor
Implementation Method 2
the yarn is wound repeatedly (e.g., 3 or 4 windings) so as to adhere to it by friction
Data Source
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AI summary
A motorized positive yarn feeder with selectable operating mode is provided with a motorized reel (12) having a yarn (Y) wound thereon, which picks up the yarn from a spool (S) and feeds it to a textile machine (TM); a control unit (CU) can operate selectively in a position control mode, in which it receives a position signal (θTM) from the textile machine (TM), and, on the basis of a position signal of the reel (12), it controls the position of the reel (12) in a closed loop according to a transmission ratio that can be set electronically with respect to the position of the textile machine (TM), or in a tension control mode, in which it controls the speed of the reel (12) in a closed loop on the basis of a tension signal of the yarn, so as to stabilize the tension of the yarn (Y) at a reference tension value or at a tension profile that can be set by a user.