Sewing Machine Threading Device with Retractable Claw
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Solution Overview
Problem
The existing threading devices for sewing machines with multiple needles, such as coverstitch sewing machines, face issues where the thread hooking claw is exposed and becomes an obstacle during sewing, potentially hooking fabric or causing injury, and require a larger machine size to accommodate the support rod and claw, making the device cumbersome.
Innovation Solution
A compact threading device design where the thread hooking support rod is shorter than the guide shaft, with a sliding member that allows the claw to retract fully within the machine, and a stopping unit to prevent lateral movement during threading, ensuring the claw is not exposed and does not interfere with sewing operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the thread hooking support rod is made longer to accommodate the rotating unit and operation lever connection, then the threading device can function properly, but the thread hooking claw becomes exposed behind and above the sewing needles, becoming an obstacle during sewing work
Solution Approach 1:
The patent applies nesting by placing the thread hooking support rod inside the housing when not in use. The rod can be inserted into and retracted from the housing, allowing it to be stored within the machine body when not needed for threading operations, thus preventing it from becoming an obstacle during sewing.
Solution Approach 2:
The patent implements dynamic positioning of the thread hooking support rod, allowing it to move between a retracted position (inside the housing) and an extended position (for threading operations). This dynamic capability enables the rod to be exposed only when needed and hidden during normal sewing to avoid interfering with fabric and operators.
2Volume of moving object
If the thread hooking support rod is made shorter to fit inside the housing, then the machine size is reduced, but the rod cannot accommodate the connection to the rotating unit or operation lever
Solution Approach 1:
The connection structures (rotating unit and operation lever) are designed to engage with the support rod in a nested manner, allowing them to connect when the rod is extended for threading operations while maintaining a compact overall structure when retracted into the housing.
Solution Approach 2:
The threading device is segmented into separate functional components: the support rod, the rotating unit, and the operation lever. This segmentation allows each component to be optimized independently - the rod can be short when retracted while still providing sufficient length when extended to accommodate connections for threading operations.
3Adaptability or versatility
If the support frame is made laterally movable to allow selective positioning of the thread hooking claw, then the device can thread multiple sewing needles, but the support frame may move unintentionally during threading operations
Solution Approach 1:
The support frame is designed to move laterally to predetermined stop positions during threading operations. The stopping unit provides periodic positioning at specific locations corresponding to different sewing needles, allowing the claw to be selectively positioned while maintaining stability during each threading action.
Solution Approach 2:
The stopping unit is configured to pre-establish predetermined stop positions for the laterally movable support frame. These stop positions are set in advance to correspond to the locations of different sewing needles, allowing the operator to selectively position the thread hooking claw at the correct needle before threading begins, ensuring both versatility and positional accuracy.
Data Source
AI summary
Provided is a sewing machine threading device that is compactly configured, and that is capable of preventing a thread hooking claw from disturbing sewing work. When an up-and-down movement operation lever 9 is raised, a thread hooking claw 10 is located above a sewing needle not to disturb sewing work. When the up-and-down movement operation lever 9 is lowered, a sliding member 15 slides along a thread hooking guide shaft 16 to cause the thread hooking claw 10 to be lowered together with a thread hooking support rod 13, rotating unit 23 rotates the thread hooking claw 10 from behind the sewing needle toward an eye of the sewing needle in connection with lowering of the thread hooking support rod 13, and the thread hooking claw 10 is inserted into the eye of the sewing needle.