Sewing Machine Upper Thread Clamp for Defined Seam Overhang
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Solution Overview
Problem
Existing sewing machines lack the ability to reproducibly produce a seam starter upper thread with a defined desired seam overhang, leading to inconsistent seam formation and excessive upper thread usage.
Innovation Solution
A sewing machine method utilizing an upper thread supply unit interacting with an upper thread clamp, providing a defined amount of upper thread for a thread trimming stitch, combined with a thread resistance generation unit and a pivotable thread pulling device, allows for precise control of the upper thread quantity, enabling reproducible seam formation with minimal thread usage and adjustable seam overhang.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional sewing machines are used without upper thread supply control, then the sewing process can proceed continuously, but the seam starter upper thread cannot be reproduced with a defined seam overhang and excessive thread is used
Solution Approach 1:
The upper thread supply unit supplies a predetermined amount of upper thread to the upper thread clamp before the sewing operation begins. This preliminary action ensures that the exact thread length needed for the defined seam overhang is available, preventing both thread waste and insufficient thread for proper seam formation.
Solution Approach 2:
The system changes the parameter of upper thread quantity from an uncontrolled continuous supply to a precisely controlled discrete amount. By adjusting the supply unit's parameters, the seam overhang can be defined within a range of 5-50 mm or more, allowing optimization of thread usage while maintaining seam quality.
2Strength
If a large amount of upper thread is supplied to ensure knot resistance, then knot resistance is maintained, but the seam overhang cannot be precisely controlled and thread usage is excessive
Solution Approach 1:
The upper thread clamp holds a predetermined amount of thread in advance, which is calculated to provide sufficient knot resistance while limiting the seam overhang to a defined maximum. This preliminary preparation ensures that the thread quantity is optimized for both strength and precision requirements.
Solution Approach 2:
The system creates a reproducible model of the ideal seam starter thread by consistently supplying the same predetermined thread amount. This copying approach ensures that each seam begins with identical thread conditions, achieving both consistent knot resistance and precise seam overhang control.
3Manufacturing precision
If the upper thread supply unit is added to control thread quantity, then precise seam overhang is achieved, but the device complexity increases
Solution Approach 1:
The thread supply control function is segmented as a separate upper thread supply unit that works in conjunction with the upper thread clamp. This segmentation allows the complex function of precise thread quantity control to be isolated in a dedicated component, making the overall system more manageable while achieving the desired precision.
Solution Approach 2:
The upper thread clamp acts as an intermediary between the upper thread supply unit and the sewing needle. It receives the predetermined thread amount from the supply unit and delivers it to the needle, mediating the complex control function and simplifying the interface with the rest of the sewing system.
4Manufacturing precision
If the upper thread is kept short to reduce overhang, then seam overhang is minimized, but knot resistance may be compromised
Solution Approach 1:
The system optimizes the thread length parameter by supplying the exact amount needed for the defined seam overhang range (5-50 mm or more). This parameter optimization ensures the thread is long enough for adequate knot resistance but short enough to achieve precise overhang control, finding the optimal balance between the two requirements.
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
This solution ensures reproducible thread cutting and precise upper thread management, allowing for optimal thread usage without knotting risks, and enables adjustable seam overhangs from 5 mm to 50 mm or more, enhancing the sewing process's reliability and efficiency.
Implementation Method 1
a lifting magnet (42) that can be actuated in order to attract the upper thread clamp (28)
Implementation Method 2
A corresponding thread resistance generation unit can be formed by an upper thread tensioning device that is already regularly provided
Data Source
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AI summary
The following procedure is used to create a seam start thread for a seam with a defined desired seam allowance on a sewing machine: First, a defined amount of top thread is positioned between a controllable top thread clamp (28) and a sewing needle (8) to perform a thread-cutting stitch. The top thread clamp (28) is then closed, preventing any further top thread (9) from being drawn from the thread supply. The thread-cutting stitch is then sewn with the defined amount of top thread. Finally, the top thread (9) is cut with a top thread cutter. This results in a consistently formed seam start thread.A sewing machine for carrying out such a production process may have an adjustable stop with which an upper thread supply unit (24) cooperates to set an upper thread quantity to be supplied.