Sewing Machine Thread Path Setting Device for Thick Threads
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Solution Overview
Problem
Existing sewing machines face challenges in effectively guiding thick or twisted upper threads, leading to undesirable looping and disruptions in the yarn path, particularly when sewing heavy or resistant materials.
Innovation Solution
The sewing machine incorporates a thread path setting device with a projecting element, such as a bracket, that can be adjusted to influence the upper thread path both in the main guide plane and perpendicular to it, ensuring the thread is guided at a sufficient distance from other components, with index marks and snap marks for precise adjustment, allowing for controlled overhang and thread slack management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional thread guide plane is used, then the thread path is simple and device complexity is low, but thick or twisted threads cannot be properly guided and looping occurs
Solution Approach 1:
The patent introduces a projecting element that extends perpendicular to the main upper thread guide plane, creating a three-dimensional thread path configuration. This allows the upper thread to be guided in multiple dimensions, preventing looping and ensuring proper thread control for thick or twisted threads, while resolving the limitation of conventional two-dimensional thread guidance.
Solution Approach 2:
The projecting element acts as an intermediary component between the upper thread guide component and the thread lever. It provides an additional guidance surface that mediates the thread path, ensuring proper thread tension and preventing disruptions without requiring complete redesign of the existing thread guidance system.
2Productivity
If the upper thread path is kept short, then sewing speed is high and productivity is improved, but threads with tendency to twist cannot be properly guided
Solution Approach 1:
By extending the thread path in the perpendicular direction through the projecting element, the patent achieves effective thread control without significantly increasing the overall thread path length in the main guide plane. This maintains sewing speed while improving thread guidance reliability for difficult-to-sew materials.
3Reliability
If the upper thread path is extended perpendicular to the guide plane, then thread guidance for thick threads is improved, but device complexity increases
Solution Approach 1:
The thread path setting device is segmented into the existing main upper thread guide plane and the additional projecting element. This modular approach allows the projecting element to be added independently to provide enhanced thread control for thick or twisted threads, while maintaining the simplicity of the original thread guidance system for standard applications.
Data Source
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AI summary
A sewing machine has a housing (2) and stitch forming tools (10) for seam formation, including a needle bar (9) for holding a sewing needle (10). A thread take-up lever (34) of the sewing machine guides an upper thread (28) and is driven synchronously with the stitch forming tools (10) and can be displaced between a top dead center and a bottom dead center. The sewing machine has upper thread guide components (33, 35) in the upper thread path before and after the thread take-up lever (34). A thread path preselection device (47) influences the length of the upper thread path between the upstream upper thread guide component (33) and the thread take-up lever (34). The thread path preselection device (47) has a projection element (48). This is arranged such that the upper thread (28) runs out of a main upper thread guide plane between the upstream upper thread guide component (33) and the thread take-up lever (34).The latter is defined by the upstream upper thread guide component (33), the thread lever (34), and the downstream upper thread guide component (35). This results in an improved thread path predetermination device.