Gas-Driven Sewing Machine Looper Threading Mechanism

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Solution Overview

Problem

Existing looper threading devices for sewing machines, such as sergers and cover stitch machines, require complex operations and multiple hand movements, making them difficult for operators to perform one-handed threading efficiently and accurately.

Innovation Solution

A gas carrying threading device with a push button shaft, set shaft, and control pin mechanism, along with a connecting movement plate and cam structure, allows for one-handed three-operation threading by simplifying the mechanism and using pressurized gas for easy thread insertion and management.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a conventional gas carrying threading device is used, then the threading pathway becomes simple and thread entanglement is reduced, but the operation becomes complex requiring both hands to concurrently perform multiple actions

Engineering Contradiction:
Improvethreading operation simplicityVSAvoidmechanism structure
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The push button shaft is designed with nested components where the set shaft with large and small diameter portions is inserted into the stopper shaft, and the control pin protrudes from the stopper shaft. This nested structure allows multiple functions to be integrated into a single compact assembly that can be operated with one hand.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The connecting movement plate serves multiple functions: it holds both the set shaft and stopper shaft, receives the control pin movement, and interfaces with the cam mechanism. This multi-functional component reduces the overall number of parts needed while maintaining the threading functionality.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Adaptability or versatility

If a looper threading device with separate looper, drive arm, and thread guide plate is used, then the threading mechanism becomes complicated and requires multiple operations

Engineering Contradiction:
Improvethreading flexibilityVSAvoidmechanism structure
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The looper, looper drive arm, and thread guide plate are merged into an integrated assembly that moves together as a single unit controlled by the push button shaft. This combination simplifies the mechanism by eliminating the need for separate control of each component while maintaining threading flexibility.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The cam mechanism is pre-configured with control groove cam portions that automatically guide the control pin through the correct sequence of movements. This preliminary design of the cam paths ensures that the threading operations occur in the proper sequence without requiring complex control logic or multiple manual steps.

Inventive Principle:
Principle #10Preliminary action

3Productivity

If manual threading operation is performed without power disconnection, then the threading can be performed continuously, but the serger may break down due to incorrect motor operation

Engineering Contradiction:
Improvethreading efficiencyVSAvoidmachine safety
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The cam mechanism provides mechanical feedback through the control pin position to the push button shaft system. The control groove cam portions are designed to automatically return the control pin to its initial position after threading completion, providing feedback that the threading cycle is complete and the motor can be safely reactivated.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The cam mechanism automatically manages the power disconnection and reconnection sequence through the control pin's movement along the predetermined cam paths. The system self-regulates the motor operation states without requiring external monitoring or control, ensuring safety while maintaining productivity.

Inventive Principle:
Principle #25Self-service

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Enables easy, mistake-free, and efficient one-handed threading with reduced risk of thread entanglement or breakage, and prevents serger breakdowns due to incorrect motor operation by disconnecting power when necessary.

Implementation Method 1

feeds a looper thread by utilizing a flow of a pressurized gas which is supplied to the hollow looper thread guide

Methodology Applied
Scientific EffectPressurized gas flow: Pressure Gradient

Data Source

PatentEP2722430B1Air-driven threading device for sewing machine
Publication Date: 2016.05.11 SUZUKI MFG CO LTD
  • EP2722430B1 patent drawingFigure 1
  • EP2722430B1 patent drawingFigure 2
  • EP2722430B1 patent drawingFigure 3A

AI summary

A threading to a looper is performed with one-touch operation. A looper threading/sewing changeover mechanism 30 including a push button 33 for a pressing operation of a push button shaft 32 that a control pin 31 is protruded and provided, a control groove cam 38 which includes a first control groove cam portion 34 - a fourth control groove cam portion 37 which receive the control pin, a connecting movement plate 40 which supports a thread guide portion and which is elastically repelled toward a threading state that a thread guide outlet of the thread guide portion contacts to a looper thread inlet of the looper by a first spring 39, and a connecting positioning plate 82 which rotates together with a main shaft 2 integrally and has a peripheral surface 80 that a tip portion 41 of the push button shaft contacts and has a notch portion 81 that the tip portion of the push button shaft is fitted is provided.