Differential Feed Sewing Machine for Side Edge Alignment

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Solution Overview

Problem

The existing sewing machines face challenges in smoothly feeding a workpiece while aligning the side end portion to a proper position due to the orthogonal feed mechanism affecting the feed by feeding dots.

Innovation Solution

A sewing machine with a feed mechanism that allows differential feed in the stitch direction, equipped with an end portion detection device to detect the workpiece ends orthogonally, and a control device to manage the feed difference between the left and right sides based on detection, ensuring precise alignment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a roller mechanism is used to feed the workpiece in a direction orthogonal to the feed direction by the feeding dots, then the side end portion alignment is improved, but the feed smoothness deteriorates due to interference between the orthogonal feed and the stitch direction feed

Engineering Contradiction:
Improveside end portion alignmentVSAvoidfeed smoothness
Core Design Contradiction:
Manufacturing precisionVSEase of operation

Solution Approach 1:

The feed mechanism is segmented into independent left and right feed rollers that can operate with different feed amounts. This allows the left and right sides to be fed differentially in the stitch direction, enabling side end portion alignment without requiring an additional orthogonal feed mechanism, thus avoiding interference between feed directions and ensuring smooth feeding.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different feed characteristics are applied to different parts of the workpiece. The left and right feed rollers provide different feed amounts locally, with the faster-feeding side compensating for delays caused by stitching operations. This local differentiation achieves precise side end portion alignment while maintaining overall feed smoothness through differential feed control.

Inventive Principle:
Principle #3Local quality

2Adaptability or versatility

If differential feed is implemented to enable left-and-right variance in feed amount, then the feed flexibility is improved, but the device complexity increases due to additional control mechanisms

Engineering Contradiction:
Improvefeed flexibilityVSAvoidcontrol mechanism complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The differential feed control is merged with the existing feed mechanism structure. The left and right feed rollers are integrated into a single coordinated system controlled by a unified control unit that receives feedback from both sides. This merging approach enables flexible differential feed operation without requiring completely separate control systems, thus limiting the increase in device complexity while maintaining high adaptability.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

Feedback sensors are installed on both the left and right feed rollers to detect feed amounts and positions. This feedback information is fed back to the control unit, which automatically adjusts the feed amounts to achieve desired alignment. The feedback mechanism enables flexible adaptation to different stitching conditions without requiring complex manual adjustment mechanisms, achieving high versatility with manageable system complexity.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP4692439A1Sewing machine
Publication Date: 2026.02.11 JUKI CORP
  • EP4692439A1 patent drawingFigure 1
  • EP4692439A1 patent drawingFigure 2
  • EP4692439A1 patent drawingFigure 3

AI summary

A sewing machine (100) includes feed mechanisms (20 and 40) that feed workpieces (C1 and C2) on a throat plate (101) in a stitch direction, and an end portion detection device (80) that detects end portions of the workpieces (C1 and C2) in a direction orthogonal to the stitch direction. The feed mechanisms (20 and 40) enables differential feed, creating a variance in feed amount in the stitch direction between the left and right sides of the stitch point position. The sewing machine (100) includes a control device (90) that controls the difference in feed amount in the stitch direction between the left and right sides by the feed mechanisms (20 and 40), based on detection by the end portion detection device (80).