Circular Stitching Device Pin Locking Mechanism
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Solution Overview
Problem
Existing circular stitching devices face difficulties in attaching and detaching the cloth-fixing pin securely without it becoming rickety, and there is a risk of accidental touch with the pin, especially when adjusting the pin support plate between movement block holes with varying clearances.
Innovation Solution
A circular stitching device with a body base, movable base, cloth-fixing pin support, and locking unit that allows the cloth-fixing pin to be easily attached and detached from the movable base while preventing accidental contact, using a locking mechanism to secure the pin in place and prevent rickety movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the fit clearance between the movement block hole and the pin support plate is increased to facilitate attachment and detachment, then the ease of operation is improved, but the pin support plate becomes rickety and unstable during use
Solution Approach 1:
The device is divided into separate components: the pin support plate, the movement block plate, and the locking means. This segmentation allows the pin support plate to be easily attached and detached while the locking means provides stability when engaged.
Solution Approach 2:
The locking means is prepared in advance on the movement block plate, ready to engage with the pin support plate. This preliminary preparation ensures that when the pin support plate is attached, it is immediately secured against rickety movement.
2Reliability
If the fit clearance is reduced to prevent the pin support plate from getting rickety, then the reliability is improved, but the ease of attachment and detachment deteriorates
Solution Approach 1:
The locking means acts as an intermediary mechanism between the movement block plate and the pin support plate. It provides the necessary connection and stability without requiring a tight fit clearance, enabling easy attachment and detachment while preventing rickety movement.
3Ease of operation
If the pin support plate is attached to the movement block plate with the cloth-fixing pin directed upward, then the ease of operation is improved, but the risk of accidental touch with the pin point increases
Solution Approach 1:
Instead of having the cloth-fixing pin directed upward which exposes the pin point, the pin is directed downward through the pin support plate. This inversion maintains ease of operation while eliminating the hazard of accidental finger contact with the sharp pin point.
4Measurement precision
If the cloth-fixing pin is inserted through the pin hole while looking into the space under the workpiece cloth, then the accuracy of pin insertion is improved, but the complexity of the operation increases
Solution Approach 1:
The pin hole is positioned on the upper surface of the pin support plate rather than requiring viewing from underneath the workpiece cloth. This dimensional change allows the user to insert the pin accurately by looking at the upper surface, greatly simplifying the operation while maintaining precision.
Data Source
AI summary
A circular stitching device for a sewing machine includes a body base attachable to a sewing bed or an upper surface of a needle plate, a movable base located on the body base so as to be movable in a predetermined direction, a cloth fixing member including a cloth-fixing pin which is passable through a workpiece cloth and is formed with an engagement portion, and a holder holding a proximal end of the cloth-fixing pin, a cloth-fixing pin support detachably attachable to the movable base thereby to support the cloth fixing member so that the cloth fixing member is detachably attachable thereto, and a locking unit which is located on the cloth-fixing pin support and is disengageably engageable with the engagement portion of the cloth-fixing pin, thereby locking the cloth-fixing pin.