Curved Needle Sewing Machine for Thick Material Seam Security

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Solution Overview

Problem

Existing sewing machines struggle to produce a secure seam, especially when dealing with thick or untransportable materials, and lack efficient synchronization of seam forming tools.

Innovation Solution

A sewing machine design featuring a curved needle with a gripper that supplies a lower thread, allowing for secure lockstitch sewing by intertwining threads, along with a belt drive system that synchronizes the needle and hook, enabling single-sided double lockstitch sewing and secure butt edge sewing of thick materials.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a curved needle with gripper is used to supply lower thread for lockstitch sewing, then secure seam production is improved, but device complexity increases

Engineering Contradiction:
Improveseam securityVSAvoidseam forming tools
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines the needle and gripper into an integrated seam forming tool assembly. The gripper is positioned on the needle and works in coordination with it to supply and interlace the lower thread with the upper thread, creating a secure lockstitch seam. This merging of functions into a coordinated assembly achieves reliable seam production while managing device complexity through functional integration.

Inventive Principle:
Principle #5Merging (Combining)

2Ease of manufacture

If a belt drive system is used to synchronize needle and hook, then ease of manufacture is improved, but speed precision may worsen

Engineering Contradiction:
Improvesynchronization mechanismVSAvoidtool synchronization
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent introduces a belt drive system as an intermediary mechanism to synchronize the rotation of the needle and hook. The belt transmits rotational motion between these components, ensuring they rotate in coordination. This intermediary mechanism provides a simple and manufacturable solution for synchronization while maintaining adequate precision for the sewing application through proper belt tensioning and alignment.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Ease of operation

If the sewing machine is designed for hand-held operation, then ease of operation is improved, but power capability worsens

Engineering Contradiction:
ImproveportabilityVSAvoidsewing capability
Core Design Contradiction:
Ease of operationVSPower

Solution Approach 1:

The patent designs the sewing machine as a segmented, modular hand-held device. The main body contains the essential seam forming tools (curved needle, gripper, hook) and drive mechanism, while allowing the machine to be held and operated manually. This segmentation enables portability and ease of operation on bulky or untransportable materials, while the concentrated power system within the hand-held unit maintains sufficient sewing capability for the intended application.

Inventive Principle:
Principle #1Segmentation

4Ease of operation

If the curved needle pierces fabric from one side and exits on the same side, then ease of operation is improved, but manufacturing precision requirements worsen

Engineering Contradiction:
Improvesingle-sided sewingVSAvoidneedle path control
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The patent employs a curved needle design that follows a specific arc path during penetration and extraction from the fabric. The curvature of the needle trajectory is engineered to enter the fabric at one location and exit at the same side at a different location, enabling single-sided sewing operation. This curved path control requires precise manufacturing of the needle guide and gripper positioning to maintain the intended trajectory and achieve the desired single-sided exit point.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Data Source

PatentEP4107321B1Sewing machine
Publication Date: 2024.10.23 PFAFF INDUSTRIESYSTEME & MASCH GMBH
  • EP4107321B1 patent drawingFigure 1
  • EP4107321B1 patent drawingFigure 2

AI summary

The invention relates to a sewing machine (1) having seam forming tools (6), comprising a needle (7) for guiding an upper thread (8) and a hook (9). The needle (7) is designed as a curved needle (7) which is pivotable about a needle pivot axis (10). In this embodiment, a distance (A) of the curved needle (7) from the pivot axis (10) is equal to a radius (r) of a curve of the curved needle (7) about the pivot axis (10). The hook (9) is designed as a hook (9) which is rotatable about a hook rotational axis (15) and has a lower thread reserve (16). The hook rotational axis (15) extends parallel to a workpiece support region. A durable seam can be produced by means of the sewing machine.