Sewing Machine Drive Shafts for Ornamental Stitch Tension Control
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Solution Overview
Problem
Traditional sewing machines for decorative and functional stitching, such as the running stitch, face challenges in managing thread tensions, which can lead to undesirable effects in ornamental seams, especially when using threads of different diameters or thicknesses, requiring frequent and costly adjustments.
Innovation Solution
A programmable sewing machine with a drive assembly of two shafts, actuated by an electric motor and rocker system, allows for adjustable thread management by inserting one or both shafts between the fabric and thread to create temporary thickness, reducing excessive tension and enabling versatile operation with various materials and threads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If traditional sewing machines use fixed needle and support plate configuration, then the machine structure remains simple, but excessive thread tensions occur in ornamental stitching
Solution Approach 1:
The patent introduces dynamic elements (first and second shafts) that can move between different positions relative to the support plate. These shafts can be inserted between the fabric and thread to create temporary thickness, dynamically adjusting the thread path and reducing excessive tension during ornamental stitching operations.
Solution Approach 2:
The shafts act as intermediary elements between the needle and the fabric/thread system. By positioning these shafts strategically, they mediate the interaction between the moving thread and stationary fabric, creating controlled friction and tension distribution that prevents excessive tightening of the ornamental stitch.
2Manufacturing precision
If mechanical members are manually adjusted for different yarn diameters, then stitching quality improves, but production time and costs increase
Solution Approach 1:
The shafts are designed with universal applicability to handle various yarn types and diameters without requiring reconfiguration. The same shaft mechanism works for different thread thicknesses by simply adjusting their positioning, eliminating the need for manual mechanical adjustments when changing yarn specifications.
Solution Approach 2:
Instead of changing mechanical parameters of the machine structure, the invention changes the operational parameters by moving the shafts to different positions. This allows the system to adapt to different yarn diameters and material properties through positional adjustments rather than structural modifications.
3Object-affected harmful factors
If shafts are inserted between fabric and thread to reduce tension, then ornamental effect improves, but device complexity increases
Solution Approach 1:
The drive assembly is segmented into modular components (first shaft, second shaft, rocker system) that can independently perform specific functions. This segmentation allows each component to be optimized for its particular role while maintaining overall system manageability and reducing the perceived complexity through functional decomposition.
Data Source
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AI summary
A sewing machine (20) for decorative and functional seams, apt to make running-stitch comprising a needle (23) with a vertical axis, arranged perpendicular to a support plate or plaque (17), where it is placed on the fabric (21) to be sewn, and operable with an alternating motion along its vertical axis, said sewing machine including a drive assembly with at least one shaft (10, 11), which drives the at least one shaft (10, 11) by means of an electric motor (12), between a working position, according to which said at least one shaft (10, 11) is inserted lower to said support plate (17) of the fabric (21) in a prefixed position corresponding to a hole (14) of said plate (17) where said needle (23) runs during its vertical motion, and a rest position, according to which said at least one shaft (10, 11) is dis-inserted from said prefixed position.