Sewing Machine Thread-Cutting Device with Segmented Catcher
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Solution Overview
Problem
Existing thread cutting devices for sewing machines face issues with reliably catching and cutting threads due to thread catching failures and cumbersome maintenance, particularly with the fixed blade's vertical orientation leading to frequent disassembly and replacement.
Innovation Solution
A thread cutting device with a horizontal hook and thread catcher that reciprocates under the needle plate, featuring a hood and guiding member to ensure reliable thread catching and a sliding fixed blade for easy maintenance, allowing the thread catcher to change position relative to the fixed blade and enabling the thread to be cut efficiently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the thread catching portion is provided at the tip of the first thread catcher, then the thread can be caught and guided to the fixed blade, but the thread catching operation fails frequently due to various thread states
Solution Approach 1:
The thread catcher is divided into multiple segments (first thread catcher and second thread catcher) with different functions. The first thread catcher catches the thread initially, while the second thread catcher catches the thread extending between the first thread catcher and the needle hole, ensuring reliable thread catching regardless of thread state
Solution Approach 2:
The second thread catcher acts as an intermediary between the first thread catcher and the fixed blade. It catches the thread extending from the first thread catcher and guides it to the fixed blade, ensuring the thread is properly positioned for cutting
2Manufacturing precision
If the fixed blade is provided with the blade standing below the needle plate in a substantially vertical direction, then the thread can be cut at the position closer to the needle hole, but the maintenance becomes cumbersome due to frequent disassembly
Solution Approach 1:
The fixed blade is divided into an upper blade and a lower blade that can be easily detached from each other. The upper blade is attached to the thread catcher while the lower blade remains stationary, allowing the upper blade to be replaced without disassembling surrounding components
Solution Approach 2:
The fixed blade is designed with movable and detachable parts. The upper blade can be easily attached and detached from the lower blade, transforming the maintenance process from cumbersome disassembly to simple blade replacement
Data Source
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AI summary
The present invention provides a thread cutting device for a sewing machine that reliably hooks and catches a thread and guides it to a fixed blade. Furthermore, the present invention provides a thread cutting device for a sewing machine whose maintenance such as a replacement of a fixed blade can be carried out easily. The thread cutting device comprises a thread catcher that has a hook portion for hooking a thread and reciprocates linearly under a needle plate to hook and catch the thread on the hook portion in the periphery of an inner hook 21 of a horizontal hook and a fixed blade that cuts the thread caught by the thread catcher. The horizontal hook has a hood 24, under which the thread catcher can reciprocate, in a part of the upper portion of a side wall portion forming a bobbin compartment that accommodates a bobbin of the inner hook 21, and a guiding member 26 that guides the thread to the area located under the hood 24 where the thread catcher 14 reciprocates is provided on the upper surface of the hood 24.