Are the chopper knife blades easy to remove or are they blocking themselves?

To remove the knife 4, the tank, turn in the opposite direction the needles of a watch the safety block 8 in the opposite direction below the tank. Then, cautiously pull the knife by entering it by the head. To put it back, insert the knife from the top down by the head, aligning the 2 notches on the knife and the bottom of the tank. Then turn the safety block 8 below the tank clockwise. To verify that the blockage is effective, pull the knife head. See the video tutorial: https://youtu.be/hmfpgf-jhaa