Sewing Machine Bobbin Thread Tension Control via Electromagnetic Actuation
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Solution Overview
Problem
Existing sewing machine bobbin thread tension controllers rely on frictional forces, making it difficult to achieve precise and accurate control of bobbin thread tension, especially in embroidery machines where consistent tension is crucial for quality workmanship.
Innovation Solution
A bobbin thread tension controller system that uses a combination of magnets and motors to rotate the bobbin, allowing for independent control of bobbin thread tension through electric current adjustments, eliminating reliance on frictional forces and enabling precise tension management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a permanent magnet is placed in a bobbin case to exert compression on the bobbin, then the bobbin thread tension is generated through frictional force between the bobbin and spindle, but this makes it difficult to accurately control the bobbin thread tension
Solution Approach 1:
The patent replaces the mechanical friction-based tension control system with an electromagnetic interaction system. Instead of using a permanent magnet to compress the bobbin against the spindle and rely on friction, the invention uses a magnetic body in the middle shuttle that interacts with an electromagnet to directly control the bobbin thread tension through magnetic force, eliminating the need for friction-based control and enabling precise adjustment through electrical parameters.
Solution Approach 2:
The patent changes the control parameter from mechanical friction force to electrical current magnitude. By adjusting the electric current supplied to the electromagnet, the magnetic force acting on the magnetic body changes, which in turn precisely controls the bobbin thread tension. This parameter change enables accurate and flexible tension control that was not achievable with friction-based systems.
2Device complexity
If the bobbin thread tension is controlled by frictional force between the bobbin thread and magnetic body, then the tension control mechanism is simplified, but the bobbin thread tension cannot be elaborately nor accurately controlled
Solution Approach 1:
The patent substitutes the friction-based mechanical control with an electromagnetic control system. The electromagnet generates a magnetic field that acts on the magnetic body, replacing the need for friction-based tension control. This substitution maintains relative simplicity in the mechanical structure while dramatically improving the precision and controllability of the bobbin thread tension through electrical parameter adjustment.
3Reliability
If additional attachment mechanisms are used to secure the bobbin, then the bobbin can be firmly attached to the middle shuttle, but the device complexity increases
Solution Approach 1:
The patent replaces mechanical attachment mechanisms with magnetic attraction. The magnetic body in the middle shuttle magnetically attracts the bobbin, securely holding it in place without requiring additional mechanical attachment devices such as clips, screws, or latches. This magnetic attachment method simplifies the overall device structure while maintaining firm and reliable bobbin attachment.
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 allows for accurate and elaborate control of bobbin thread tension, improving the quality of embroidery by ensuring consistent tension across multiple embroidery heads and reducing the need for additional attachment mechanisms, while minimizing operational noise.
Implementation Method 1
the first magnet and the second magnet that rotates the first magnet
Implementation Method 2
An electric current is caused to flow into a coil of the electromagnetic, thereby energizing the electromagnet. The electromagnet is thereby actuated so as to repel the permanent magnet.
Data Source
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AI summary
There is provided a sewing-machine bobbin thread tension controller capable of elaborately, accurately controlling bobbin thread tension without depending on frictional force. A bobbin thread tension controller includes an outer shuttle 110, a middle shuttle presser 130, a middle shuttle 150, a bobbin thread tension control mechanism 200, a shuttle actuation unit 250, and a bobbin 300. The middle shuttle 150 has a magnet 190. A magnet 270 is disposed, in close proximity to the magnet 190, on an arm 260 attached to a rotary shaft of a shuttle actuation motor 252 provided in the shuttle actuation unit 250. The middle shuttle 150 is rotated by rotating the magnet 270 by means of the motor 252. Further, a rotary disc 210 is provided, in close proximity to the middle shuttle 150, on a rotary shaft of a bobbin thread tension control motor 202 of the bobbin thread tension control mechanism 200 and is provided with a magnet 214. A magnet is disposed on a part of the bobbin 300 facing the rotary disc 210. The motor 202 rotates the bobbin 300.