V-Shaped Elastic Pre-Stress Device for Sewing Machine Thread Tension
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing sewing machine thread pre-stress devices suffer from material fatigue, improper tension due to protruding portions, and size-related issues that affect thread tension and fabric quality.
Innovation Solution
A sewing-thread pre-stress device featuring a sewing-thread support with an elastic V-shaped pre-stress supply member, an abutting member, and a top cover, which provides controlled thread tension and prevents fatigue by using elastic materials and precise geometry to manage thread pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a sponge is used as the pre-stress supply member, then the sewing thread can be clamped tightly to provide proper tension, but the sponge is prone to fatigue and deterioration after being used for a period of time, resulting in failure to provide appropriate pressing force
Solution Approach 1:
The patent changes the material parameter from sponge (elastic foam) to V-shaped elastic piece (metal or rigid elastic material). This parameter change transforms the pre-stress supply mechanism from one that degrades over time to one that maintains consistent elastic properties, resolving the contradiction between initial effectiveness and long-term durability.
2Reliability
If protruding portions are added to the top cover to press against the abutting member, then the sewing thread can be clamped more effectively, but the protruding portions are likely to interfere with the extending of the sewing thread and press the sewing thread
Solution Approach 1:
The patent removes the protruding portions from the top cover design. Instead, the clamping function is achieved through the V-shaped elastic piece itself, which naturally provides pressing force against the abutting member without requiring additional protruding structures that would interfere with thread extension.
Solution Approach 2:
Instead of adding protruding portions to press down on the abutting member, the invention inverts the approach by using the V-shaped elastic piece to directly provide upward pressing force against the abutting member, eliminating the need for downward protruding portions and their associated interference problems.
3Force
If the size of the protruding portions is made large, then the abutting member can be pressed more effectively, but the width of the thread space becomes too wide, resulting in failure to provide proper tension
Solution Approach 1:
The V-shaped elastic piece concentrates the pressing force locally at its tip against the abutting member, while the thread space width is controlled by the overall geometry of the device. This local quality approach allows effective pressing force without compromising thread tension control through precise geometric design.
4Reliability
If the size of the protruding portions is made small, then the thread space width is reduced for better tension control, but the protruding portions may recover due to the restoring force of the metal, failing to produce the desired effect
Solution Approach 1:
The patent changes the material and geometric parameters by using a V-shaped elastic piece with specific elastic properties instead of small protruding portions. This parameter change ensures sufficient pressing force is generated through the elastic deformation of the V-shaped piece itself, eliminating the recovery issue associated with small metal protruding portions.
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
The solution ensures consistent and moderate thread tension for various thread diameters, preventing fabric wrinkling and knotting while extending the device's lifespan by using elastic materials that resist fatigue.
Implementation Method 1
a pre-stress supply member (20), made of an elastic material, provided in the accommodating groove (11)
Data Source
AI summary
A sewing-thread pre-stress device for a sewing machine includes: a sewing-thread support, a pre-stress supply member, an abutting member and a top cover. The sewing-thread support includes an accommodating groove with a groove bottom. The pre-stress supply member is made of elastic material, provided in the accommodating groove, and has a folding portion which has two extension portions with one end connected to two sides of the folding portion. The abutting member is disposed on the pre-stress supply member, and the two abutting portions abut against the abutting member. The top cover is disposed on the abutting member and fixed to the sewing-thread support to define a thread space between the top cover and the abutting member for allowing a sewing thread to be inserted therethrough. The member is elastic and V-shaped, therefore the elastic force change is relatively small, which can provide the sewing thread an appropriate tension.