Input: yellow screw driven by a electric motor.
Violet frame carrying pink pinions that engage with stationary grey racks and with green racks fixed to green frame.
Green frame carrying orange pinions that engage with violet racks fixed to the violet frame and with blue racks fixed to blue frame.
The yellow screw – violet nut drive makes the violet frame goes up down.
The green frame moves two times faster than the violet frame.
The blue frame moves three times faster than the violet frame.
Front part of the mechanism is cut-off for easy understanding.