Lower Thread Winding Device with Adjustable Sensor Lever
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Solution Overview
Problem
The existing lower thread winding device lacks the ability to adjust the amount of thread wound on a bobbin, often resulting in excess or insufficient thread, as it continues to wind until a predetermined outside diameter is reached without user control.
Innovation Solution
A lower thread winding device with a sensor lever, contact, cam piece, and controller that allows the user to adjust the thread winding by shifting the contact position, enabling precise control over the motor's operation based on detection results, allowing for adjustable thread length.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the motor continues to be driven until the outside diameter of the lower thread reaches a predetermined outside diameter, then the thread winding process is simple to control, but the amount of lower thread wound on the bobbin cannot be adjusted by the user
Solution Approach 1:
The sensor lever is made rotatable about a first rotation shaft, allowing its detection position to be dynamically adjusted. The cam piece with varying radial distance creates different detection thresholds based on the lever's rotation angle, enabling the system to adapt the thread winding amount without changing the basic control mechanism.
Solution Approach 2:
The invention changes the detection parameter by varying the radial distance of the cam piece's outer peripheral portion from the first rotation shaft. By rotating the sensor lever to different angles, the effective detection radius changes, which directly controls when the sensor triggers the motor to stop, thus adjusting the thread winding amount.
2Measurement precision
If a distance measuring sensor is used to detect when the outside diameter reaches a predetermined value, then the control is precise, but the user cannot adjust the thread winding amount to match their needs
Solution Approach 1:
The sensor lever's rotatable design allows the precise detection mechanism to be repositioned angularly, creating multiple detection thresholds. This maintains measurement precision while adding adaptability, as each rotation position corresponds to a specific detection radius and thus a specific thread winding amount.
Solution Approach 2:
The user can preliminarily adjust the sensor lever's rotation position before thread winding begins, pre-setting the detection threshold according to the desired thread amount. This preliminary adjustment enables the precise detection system to be customized for different winding requirements without losing its precision during operation.
3Device complexity
If the detection result changes only when a fixed outside diameter is reached, then the control mechanism is simple, but the thread amount may exceed or fall short of the user's desired amount
Solution Approach 1:
Rather than creating multiple fixed detection mechanisms, the invention uses a single dynamic sensor lever that can be rotated to different positions. This maintains relative simplicity in the control mechanism while providing adjustability, as one movable component replaces what would otherwise require multiple fixed components.
Solution Approach 2:
The sensor lever serves multiple functions: it acts as both the detection element and the adjustment mechanism. By rotating the lever, the same sensor can detect different outside diameters, making the control mechanism universally applicable to different thread winding requirements without needing separate detection systems for each threshold.
Data Source
AI summary
In a lower thread winding device, a motor rotates a thread winding shaft on which a bobbin is mounted. A sensor lever includes a contact portion contactable with a lower thread wound on the bobbin, and a cam piece. A contact includes a pin configured to contact the cam piece and rotates between a first position at which the pin contacts a first outer peripheral portion of the cam piece, and a second position at which the pin contacts a second outer peripheral portion of the cam piece. A lever shifts a position of the pin located when the contact is at the first position. The controller drives the motor when the contact is at the first position and stops driving the motor upon receipt of a detection result, by the detector, indicating that the contact is at the second position.