Flat Knitting Machine Yarn Feeding Control
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Solution Overview
Problem
The flatbed knitting machine struggles to maintain precise feed lengths of yarn, especially during remedial processes in the necessary yarn feeding mode, due to variations in yarn tension and tilt angle, leading to inaccuracies in stitch loop length and requiring mode changes that disrupt stitch adjustment.
Innovation Solution
A flatbed knitting machine with a yarn feeding system that calculates yarn length based on knitting data, uses a buffer arm with a tilt angle sensor to monitor and adjust yarn feeding, and switches to a buffer condition mode when tilt angles exceed predetermined limits, allowing for continuous stitch adjustment and precise yarn feeding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the necessary yarn feeding mode is used to feed knitting yarn of calculated length, then the manufacturing precision of stitch loop length is improved, but the reliability of yarn feeding is worsened when tilt angle exceeds predetermined range
Solution Approach 1:
The control unit continuously monitors the tilt angle of the buffer arm via the tilt angle sensor and compares it against predetermined ranges. When the tilt angle exceeds the range during necessary yarn feeding mode, the system automatically switches to buffer condition mode, creating a closed-loop feedback mechanism that maintains reliable yarn feeding while preserving stitch loop length precision.
Solution Approach 2:
The system dynamically switches between two operating modes (necessary yarn feeding mode and buffer condition mode) based on real-time tilt angle conditions. This dynamic adaptation allows the machine to maintain manufacturing precision when conditions permit while ensuring reliability when tilt angle limits are approached, resolving the contradiction between precision and reliability.
2Ease of operation
If the buffer arm tilt angle is kept constant to control yarn feeding, then the ease of operation is improved, but the manufacturing precision of yarn length is worsened
Solution Approach 1:
The system transitions from a static fixed tilt angle approach to a dynamic dual-mode system. In necessary yarn feeding mode, the tilt angle varies within a controlled range to achieve precise yarn length feeding. In buffer condition mode, the tilt angle is maintained constant to simplify operation and ensure reliability. This dynamic adaptation resolves the contradiction between operational simplicity and feeding precision.
Solution Approach 2:
The system changes the operating parameters (tilt angle range, feeding mode) based on real-time conditions. When in necessary yarn feeding mode, the tilt angle is allowed to vary within a predetermined range to achieve precise yarn length control. When tilt angle approaches limits, the system switches to buffer condition mode with constant tilt angle. This parameter adaptation enables both precision and ease of operation.
3Manufacturing precision
If stitch adjustment is performed continuously to maintain uniform fabric, then the manufacturing precision of fabric quality is improved, but the device complexity of control system is worsened
Solution Approach 1:
The control unit uses feedback from the tilt angle sensor to automatically determine when stitch adjustment is needed and executes adjustments based on predetermined knitting data. This automated feedback-based control reduces the complexity of manual operation while maintaining continuous fabric quality uniformity through precise yarn length control.
Solution Approach 2:
The system performs preliminary calculations of required yarn length based on knitting data before actual knitting occurs. The control unit pre-determines the necessary yarn feeding parameters and adjusts the buffer arm operation accordingly, enabling continuous stitch adjustment without requiring complex real-time calculations during knitting, thus reducing control system complexity.
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 solution enables precise yarn feeding and stitch adjustment, maintaining accuracy even during remedial processes and reducing errors in yarn length, ensuring consistent fabric quality across the entire knitting width.
Implementation Method 1
a tilt angle sensor 17 to detect this tilt angle is installed
Implementation Method 2
The buffer arm 7 is energized in the direction where the head end side 9 rolls away from the side cover 5 by a torque spring 16 equipped to the base end side 8
Implementation Method 3
The yarn feeding device 6 is able to send out the knitting yarn 4 to the buffer arm 7 side or pull back the knitting yarn 4 from the buffer arm 7 side, with the knitting yarn 4 clipped between a master roller 10 and a slave roller 11
Data Source
Figure 1(a)~1(b)
Figure 2(a)~2(c)
Figure 3
AI summary
To provide a flatbed knitting machine that can maintain the accuracy for the feed lengths of knitting yarn even when remedial process is performed while the yarn is being fed in a necessary yarn feeding mode. In a flatbed knitting machine 31, the rotational angle of a master roller 10 of a yarn feeding device 6 is detected by an encoder 32. As the tilt angle of a buffer arm 7 approaches the lower limit or the upper limit in the midst of the necessary yarn feeding mode, the mode is switched to a fixed arm angle mode as remedial process. A knitting controller 33 performs stitch adjustment even during remedial process. The length of knitting yarn 4 fed from between the master roller 10 and a slave roller 11 to the buffer arm 7 is calculated on the basis of the difference in the rotational angles detected by the encoder 32. As shown in (b), the timing of measurement by the encoder 32 at which the knitting controller 33 performs stitch adjustment in the fixed arm angle mode corresponds to the inside of the knitting width.