Rubo holds your paper towels and helps you tearing the sheets. When you push down on his head, his arms will rotate 180 degrees and tear off the sheet you are holding. The mechanism is loosely based on that of a spinning top. The center rod can be pushed down through the platform on which the roll rests. This is converted into rotary movement of the arms by a pin on the center rod that moves through a helical slot in the inside of the ring attached to the arms. When releasing the pressure, a spring between the center rod and base moves the rod back up. The pin now acts like a ratchet so it does not move the arms. The CAD files do not yet contain this mechanism but shows the basic configuration.