Principle of Lock Stitch formation
The mechanism of lock stitch formation can be illustrated as below-
1. The needle is penetrated into the fabric.
2. The needle reaches to its lowest position and the rotary hook is ready to catch the needle thread.
3. As the needle moves upward from its lowest position, the needle thread forms a loop which is caught by the point of the rotary hook.
4. The hook enlarges the needle thread loop & is guided around the bobbin thread.
5. The take – up lever tighten the stitch into the fabric & the fabric is fed forward.
6. The cycle repeats.