Bobbin With Thread End Housing Gap

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Solution Overview

Problem

Existing bobbin designs for sewing machines often result in thread ends becoming loose due to vibration and rotation, leading to entanglement and wastage, with previous solutions either deforming the thread or requiring complex handling and attachment methods that can cause stitch failures.

Innovation Solution

A bobbin design featuring a gap between the outer flange and the bobbin main body flange for housing the thread end, with protrusion sections to prevent thread come-off, allowing secure retention without deformation and reducing the risk of thread cutting during sewing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a thread stopper ring is used to retain the thread end, then the thread can be prevented from coming loose, but the thread stopper ring must be detached during sewing work and is likely to be lost, resulting in extremely low workability

Engineering Contradiction:

Improvethread retentionVSAvoidworkability

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The thread stopper function is merged with the bobbin structure itself. The groove is formed directly on the bobbin flange, eliminating the need for a separate thread stopper ring. This integration ensures the thread retention function is always present and cannot be lost or detached during sewing operations.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The bobbin structure provides its own thread retention function through the groove formed on its flange. The groove automatically retains the thread end without requiring external components or additional operations by the user.

Inventive Principle:

Principle #25Self-service

2Reliability

If a V-shaped cutout is formed in the flange to lock the thread end, then the thread can be retained, but the cutout may come into contact with the needle thread and cause stitch performance failure and thread cut

Engineering Contradiction:

Improvethread retentionVSAvoidstitch performance failure

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The groove is positioned at a specific location on the flange that is optimized for thread retention while minimizing interference with needle thread passage. The local geometry of the groove is designed to hold the thread end securely without protruding into the needle thread path.

Inventive Principle:

Principle #3Local quality

3Reliability

If a commercially available thread spool is used to wind the bobbin thread, then the thread end can be retained, but the thread spool cannot be directly applied to the configuration of a bobbin case and cannot be attached to the inner shuttle

Engineering Contradiction:

Improvethread retentionVSAvoidcompatibility with bobbin case

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The bobbin design maintains compatibility with standard bobbin cases and inner shutles while incorporating thread retention functionality. The groove is integrated into the universal bobbin structure, allowing it to function in both thread winding and sewing operations without requiring specialized components.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS9540212B2Bobbin

Publication Date: 2017.01.10 JANOME CORP

AI summary

A bobbin includes a bobbin main body including flanges at both ends of a bobbin winder spindle for winding the bobbin thread and an outer flange attached to one of the flanges (a second flange) of the bobbin main body. A gap in which a thread end of the bobbin thread is housed is provided between the outer flange and the flange of the bobbin main body.