The main reason I wanted to disassemble this movement is that I have a watch with a skeletonized version of it and I find the automatic system interesting. The Seagull ST16 is also known as the TY2806.
According to information found on the Caliber Corner page, the automatic system is known as the magic lever and was developed by Seiko. It can be seen in the Seiko 7005 I disassembled.
The system works thanks to an excentric pin being rotated by the rotor. That movement of the pin moves the arms of the lever to either pull or push the ratchet wheel. Because of the shape of the ratchet wheel teeth, the lever arm moving to unwind the ratchet wheel will simply slip over the teeth. More details can be found on the thematic page on automatic movements.
