Knitting machine and defect detection system
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Solution Overview
Problem
Existing techniques for detecting defective knitting in knitted fabrics are inefficient, as they only detect defects in completed fabrics, leading to unnecessary costs and difficulties in identifying defects in fabrics that contract in the width direction, such as rib knitted fabrics.
Innovation Solution
A knitting machine equipped with a knitting needle, an image capturer, a determiner, and a position storage system that compares the state of stitches in real-time, allowing for early detection of defective knitting by imaging stitches from above or below the needle beds and moving along them, enabling accurate detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If defect detection is performed on completed knit fabric, then detection can be performed using existing image capture techniques, but unnecessary costs (power, yarn, knitting time) occur and defects in contracting fabrics are difficult to detect
Solution Approach 1:
The patent applies preliminary action by performing defect detection on stitches while they are still held on the knitting needles, before the knitting process is completed. The image capturer captures images of stitches at this intermediate stage, allowing defects to be detected early without wasting additional yarn, power, or knitting time that would be required if detection were postponed until the fabric was fully knitted.
Solution Approach 2:
The patent replaces traditional mechanical defect detection methods with an optical imaging system. An image capturer (camera) captures images of stitches held on the knitting needles, and these images are processed by a defect detection unit to identify defective stitches. This substitution of mechanical inspection with optical imaging enables non-contact, high-precision detection without physical manipulation of the fabric.
2Ease of operation
If image capture is performed from above the needle bed gap, then stitches can be easily imaged, but the system requires complex positioning and multiple image capturers for双面 knitting
Solution Approach 1:
The patent applies inversion by capturing images from below the needle bed gap rather than from above. The image capturer is positioned to capture images of stitches through the needle bed gap from the opposite side, which simplifies the imaging geometry and reduces the need for complex positioning systems or multiple image capturers for double-sided knitting machines.
3Quantity of substance
If the image capturer is made movable along the needle beds, then fewer image capturers are needed, but the system complexity and control difficulty increase
Solution Approach 1:
The patent applies dynamics by making the image capturer movable along the needle beds instead of stationary. The image capturer can be positioned at different locations to capture images of stitches held on different sets of knitting needles, reducing the total number of image capturers required while maintaining comprehensive defect detection coverage through controlled movement and positioning.
Data Source
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AI summary
A knitting machine 1 includes a knitting needle 11 configured to knit a knitted fabric K, an image capturer 22 configured to image a stitch held on the knitting needle 11, a determiner 60 configured to compare a state of the stitch imaged by the image capturer 22 with a state of the stitch in a normal state and perform a quality determination of the stitch, and a position storage 60 configured to store a position of the stitch imaged by the image capturer 22.