The brown driving pulley transmits rotation to the blue shaft through a friction clutch. A worm drive is used to get large trasmission ratio thus the working shaft can get large turn number (17 for this case).
The green worm wheel has 20 teeth and the number of the blue worm starts is 1.
To avoid reverse rotation for the new working cycle, at the end of the working process raise the orange stopper and rotate the green worm wheel to the starting position.