Chain-Off Thread Cutter With Foreign Matter Detection

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Solution Overview

Problem

Existing chain-off thread cutters mistakenly cut foreign matter along with the chain-off thread due to the lack of a detection mechanism.

Innovation Solution

A chain-off thread cutter equipped with a movable blade, a fixed blade, a foreign matter detector, and a control unit that stops the driving mechanism when foreign matter is detected, preventing the blade from engaging with non-thread materials.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a chain-off thread cutter is provided without a detection mechanism, then the cutting operation is simple and fast, but foreign matter may be mistakenly cut along with the chain-off thread

Engineering Contradiction:

Improveaccuracy of cutting operationVSAvoidstructure of chain-off thread cutter

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The foreign matter detector is positioned to detect foreign matter before the movable blade reaches it. The control unit receives the detection signal in advance and stops the driving unit before the blade contacts the foreign matter, preventing mistaken cutting while maintaining a relatively simple overall structure

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The control unit acts as an intermediary between the foreign matter detector and the driving unit. It receives signals from the detector and controls the driving unit to stop, creating a buffer that prevents direct contact between the blade and foreign matter while maintaining system simplicity

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If a foreign matter detector and control unit are added to the chain-off thread cutter, then foreign matter detection capability is improved, but the device complexity increases

Engineering Contradiction:

Improveforeign matter detection accuracyVSAvoidcontrol system structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces complex mechanical detection mechanisms with a simpler sensor-based foreign matter detector and electronic control system. This substitution achieves reliable foreign matter detection while keeping the overall device complexity manageable through the use of modern sensing and control technologies

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentUS12371834B2Chain-off thread cutter

Publication Date: 2025.07.29 JUKI CORP

AI summary

A chain-off thread cutter for cutting a chain-off thread formed by a sewing machine. The chain-off thread cutter including: a fixed blade; a movable blade that moves toward and away from the fixed blade; a driving unit that drives the movable blade to move the movable blade; a foreign matter detector that detects foreign matter present in a track of the movable blade; and a control unit that stops the driving unit when the foreign matter is detected by the foreign matter detector.