When sewing, the sewing machine acts as a mechanism for conveying, recovering the needle thread and tightening the stitch in the process of forming the stitch. Mainly can be divided into the following:
1. Cam thread take-up mechanism: a mechanism that drives the thread take-up lever to move by a cam
2. Connecting rod thread take-up mechanism: a mechanism that drives the movement of the thread take-up mechanism by a four-bar linkage mechanism
3. Slide bar thread take-up mechanism: a mechanism that drives the movement of the thread take-up mechanism by the crank-slide bar mechanism
4. Rotary thread take-up mechanism: a mechanism that uses one or two discs or other shaped components equipped with thread-take-up pins to perform a thread-take-up motion with a rotary motion
5. Needle bar thread take-up mechanism: a mechanism that fixes the thread-passing or thread-clamping device on the needle bar, or directly fixes the thread take-up lever installed on the needle bar.
