Overlock Machine Threader Using Opposing Rotation
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Solution Overview
Problem
Existing overlock machines with multiple sewing needles face challenges in compact design and cost due to the complexity of threading mechanisms, requiring precise control of multiple parts to accommodate varying needle eye heights.
Innovation Solution
A threader system with a single vertically moving and rotatable threading shaft, featuring a threading hook and guide member that rotate in opposite directions, allows for reliable one-handed threading across multiple needles regardless of height differences, using a cam mechanism to adjust the shaft's position and reduce machine size and cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a threading shaft is attached to incline with respect to the needle bar motion direction to accommodate varying needle eye heights, then threading capability across multiple needles is improved, but the number of parts increases and machine size and cost increase
Solution Approach 1:
The patent employs dynamic adjustment mechanisms including a vertically movable needle bar that can be positioned at different heights, and a rotatable threading shaft that can be oriented at different angles. This allows the threading mechanism to adapt to varying needle eye heights without requiring multiple fixed threading shafts, thereby reducing part count while maintaining threading capability across all needles.
Solution Approach 2:
The single threading shaft is designed to perform multiple functions by combining vertical movement and rotational capability. It can thread needle eyes at different heights and different angular positions, replacing what would traditionally require multiple dedicated threading shafts for each needle, thus reducing the overall number of parts while maintaining universal threading capability.
2Adaptability or versatility
If a threading shaft is attached to incline with respect to the needle bar motion direction to accommodate varying needle eye heights, then threading capability across multiple needles is improved, but machine size increases
Solution Approach 1:
The patent uses dynamic positioning of the needle bar with vertical movement capability and rotational adjustment of the threading shaft. This allows the system to accommodate varying needle eye heights within a compact footprint by moving and rotating components rather than expanding the machine structure to accommodate fixed inclined threading shafts for each needle height.
Solution Approach 2:
The patent introduces vertical movement of the needle bar as an additional degree of freedom, allowing needle eyes at different heights to be brought into the threading zone vertically rather than requiring horizontal expansion of the machine. The threading shaft's rotational capability adds another dimension of adjustment, enabling compact arrangement of threading operations.
3Adaptability or versatility
If a threading shaft is attached to incline with respect to the needle bar motion direction to accommodate varying needle eye heights, then threading capability across multiple needles is improved, but manufacturing cost increases
Solution Approach 1:
The patent designs a single multi-functional threading shaft that can thread needle eyes at different heights and angular positions. This replaces what would traditionally require multiple dedicated threading shafts, reducing the number of parts to manufacture, assemble, and maintain, thereby reducing manufacturing cost while maintaining the ability to thread all needles with varying eye heights.
Solution Approach 2:
The patent employs dynamically adjustable components including a vertically movable needle bar and a rotatable threading shaft. This dynamic approach allows a single threading shaft to serve multiple needles at different heights, reducing the total number of threading components needed, which directly reduces manufacturing cost while preserving threading capability across all needles.
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 compact and cost-effective threading of overlock machines by simplifying the threading process with a single shaft mechanism, ensuring reliable threading across needles of varying heights.
Implementation Method 1
using a cam mechanism to adjust the shaft's position
Data Source
AI summary
Provided is a threader for an overlock machine that allows the whole machine to be made compact and allows an operator to carry out threading reliably with one hand. The threader comprises: a threading shaft that moves vertically and is supported rotatably, with a shaft core being taken as a central axis; a threading hook that is fixed to the lower end of the threading shaft and that includes a hook part that can be inserted into the needle eye of a sewing needle and a first guide part that guides the hook part to the needle eye; and a thread guide member that guides a needle thread to the hook part in the vicinity of the descent limit point of the threading shaft. The threading hook is rotated by a predetermined angle so that the hook part is inserted into the needle eye of the sewing needle in the vicinity of the descent limit point of the threading shaft. The threading hook and the thread guide member are rotated in opposite directions to each other and thereby the thread guide member is rotated by the predetermined angle so that the thread hooking part intersects the sewing needle beyond the position of the sewing needle in the vicinity of the descent limit point of the threading shaft. The threading shaft moves according to the relative positional relationship between the needle eyes of a plurality of sewing needles.