Sewing Machine Circular Stitching Feed Correction
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Solution Overview
Problem
Existing sewing machines face issues with puckering during circular stitching, leading to misalignment between the first and final iterations of the stitch pattern, even when using revision data calculated based on the radius and stitch pattern length.
Innovation Solution
A sewing machine equipped with a circular stitching device that anchors the workpiece rotatably, featuring a feeding device, sewing device, processor, and memory to adjust feed amount data dynamically based on actual movement discrepancies, ensuring precise alignment of stitches around a circular shape.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If revision data is calculated based on radius and stitch pattern length, then the circumference can be computed and the stitch pattern can be sewn repeatedly, but misalignment occurs between the first and final iterations due to puckering
Solution Approach 1:
The system captures images of the workpiece before and during feeding, detects the position of a mark on the workpiece, and uses this feedback information to calculate the actual feeding amount. This closed-loop feedback mechanism allows the system to compensate for puckering and maintain alignment precision between the first and final iterations of the stitch pattern.
Solution Approach 2:
The patent replaces traditional mechanical measurement methods with an optical detection system. Instead of using mechanical encoders or position sensors to measure workpiece movement, the system uses image capture devices to detect the position of marks on the workpiece, thereby substituting mechanical measurement with optical measurement to achieve more accurate feeding amount detection.
2Productivity
If the workpiece is fed based on planned feed amount data, then the stitch pattern can be formed, but actual movement differs from planned movement due to puckering
Solution Approach 1:
The system performs preliminary action by capturing an image of the workpiece before feeding and detecting the mark position in advance. This allows the system to calculate the actual feeding amount before completing the feeding operation, enabling real-time correction of feed amount data for subsequent iterations while maintaining sewing speed.
Solution Approach 2:
The system implements feedback by detecting the actual position of the mark on the workpiece during feeding and using this information to revise the feed amount data. This feedback loop ensures that the actual movement of the workpiece matches the planned movement, maintaining both productivity and precision.
3Adaptability or versatility
If the anchor position is set apart from the needle drop point, then the workpiece can be anchored rotatably for circular stitching, but the distance specification adds complexity to the system
Solution Approach 1:
The system introduces a mark on the workpiece as an intermediary element. Instead of directly tracking the complex rotational movement of the workpiece around the anchor point, the system detects the position of this simple mark using image capture. This intermediary simplifies the measurement and calculation process while enabling circular stitching capability.
Data Source
AI summary
A sewing machine to which a circular stitching device configured to anchor a sewing workpiece in a rotatable manner includes a feeding device, a sewing device, a processor, and a memory. The memory is configured to store computer-readable instructions that, when executed by the processor, cause the sewing machine to execute the steps of specifying a distance between an anchor position and a needle drop point, changing first feed amount data into second feed amount data based on the specified distance and a length of a stitch pattern, specifying an actual amount of movement of the sewing workpiece, and revising the second feed amount data for at least one stitch, among stitches of a plurality of iterations of the stitch pattern, that is not yet formed, based on a difference between the specified actual amount of movement and a planned feed amount indicated by the second feed amount data.