Sewing Machine Feed Adjustment for Aligned Reverse Stitching
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Solution Overview
Problem
The existing sewing machines face misalignment issues between forward and reverse stitches due to differences in maximum backward and forward feed amounts, leading to poor appearance and limited usability in reverse stitching.
Innovation Solution
A sewing machine with a feed amount adjustment mechanism that compares the set forward feed amount with the maximum backward feed amount and adjusts the total backward feed amounts for multiple stitches to coincide with or exceed the forward feed amount, ensuring alignment and improving the appearance of reverse stitching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the forward feed amount is larger than the maximum backward feed amount, then the stitch length can be increased, but misalignment occurs between forward and reverse stitches
Solution Approach 1:
The patent divides the reverse stitching process into multiple segments (multiple reverse stitches) instead of using a single reverse stitch. By segmenting the reverse feed into multiple smaller feed amounts, the system can collectively achieve alignment with the forward stitch while maintaining a larger forward feed amount for better stitch length and usability.
Solution Approach 2:
The patent transitions from considering only the single-dimension feed amount to incorporating the number of stitches as an additional dimension. By adjusting both the feed amount per stitch and the number of reverse stitches, the system resolves the alignment issue while preserving the desired forward stitch length.
2Manufacturing precision
If the forward feed amount is adjusted within the range of the maximum backward feed amount, then alignment is achieved, but the stitch size becomes smaller and usability is limited
Solution Approach 1:
The patent segments the reverse stitching into multiple stitches, allowing each individual reverse stitch to have a smaller feed amount (within the maximum backward feed amount range) while the cumulative effect of multiple segments achieves the desired alignment and maintains usability.
3Adaptability or versatility
If the maximum backward feed amount is smaller than the maximum forward feed amount, then reverse stitching can be performed, but misalignment occurs leading to poor appearance
Solution Approach 1:
The patent segments the reverse feed into multiple smaller feed amounts that can be executed within the mechanical constraints of the feed mechanism. By using multiple segments, the cumulative reverse feed amount can match the forward feed amount, achieving alignment while maintaining reverse stitching capability.
Solution Approach 2:
The patent employs periodic reverse stitching actions (multiple discrete reverse stitches) rather than a single continuous reverse feed. This periodic execution allows the system to work within the mechanical limitations of the feed mechanism while achieving the desired alignment through repeated cycles of feeding and stitching.
Data Source
AI summary
A sewing machine includes a feed amount setting part and a feed amount adjustment part. In the feed amount setting part, a forward feed amount for one stitch of forward stitching is set. In the feed amount adjustment part, the forward feed amount which is set by the feed amount setting part is compared with the maximum backward feed amount for one stitch of reverse stitching which is determined by a feed mechanism. Then, in the feed amount adjustment part, when the forward feed amount is larger than the maximum backward feed amount, the total amount of backward feed amounts for plural stitches of backward stitching is adjusted so as to coincide with the total amount of the forward feed amounts for one stitch or more of forward stitching.