Needle-Synchronized Sewing Holder Control for Buttonhole Seams

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Solution Overview

Problem

Existing sewing machines face challenges in improving the quality of seams, particularly when sewing buttonholes, due to the interaction between the sewing needle and the frame movement.

Innovation Solution

A sewing machine external unit equipped with a holder, driver, position detector, and controller that detects the sewing needle's position and controls the holder's movement to synchronize with the needle's vertical and horizontal movements, preventing interference and enhancing seam quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a frame, ratchet mechanism, and top are used to move the frame in the shape of buttonholes, then the sewing machine can sew buttonholes, but the interaction between the sewing needle and frame movement reduces seam quality

Engineering Contradiction:
Improveability to sew buttonholesVSAvoidseam quality
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The patent replaces the mechanical ratchet mechanism with an electromagnetic actuator that directly drives the holder along the bed. This substitution eliminates the complex mechanical interactions between the needle and frame movement, allowing for precise control of holder position and movement timing, thereby improving seam quality while maintaining buttonhole sewing capability

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent implements dynamic control where the holder's movement is synchronized with the needle's position through a controller that receives position feedback. The holder moves only when the needle is in appropriate positions, creating a dynamic coordination between needle and holder that prevents interference and improves seam quality during buttonhole sewing

Inventive Principle:
Principle #15Dynamics

2Adaptability or versatility

If the holder is moved along the bed during sewing, then various seam shapes and patterns can be achieved, but interference between needle and holder movement may occur

Engineering Contradiction:
Improveseam shapes and patternsVSAvoidinterference prevention
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent employs a position detector that continuously monitors the needle's position and feeds this information back to the controller. The controller uses this feedback to determine the appropriate timing for holder movement, ensuring the holder only moves when the needle is in safe positions. This feedback mechanism prevents interference while enabling various seam shapes and patterns

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The controller plans and coordinates holder movement in advance based on the desired seam pattern, ensuring movements are timed to occur only when the needle is in appropriate positions. This preliminary coordination prevents interference before it can occur, allowing reliable creation of various seam shapes and patterns

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP4379105B1Sewing machine external unit
Publication Date: 2026.02.04 JUKI CORP
  • EP4379105B1 patent drawingFigure 1
  • EP4379105B1 patent drawingFigure 2
  • EP4379105B1 patent drawingFigure 3

AI summary

The disclosure improves the quality of seams in sewing using a sewing machine, and includes: a holder (11) holding fabric (S); a driver (12) being detachable from a bed (7) of a sewing machine (1) and driving the holder along an upper surface (7a) of the bed; a position detector (13) detecting a position of a sewing needle (3) of the sewing machine in an up-down direction; and a controller (16) controlling driving of the holder, which is performed by the driver, based on a detection result of the position detector.