Blue plate can be positioned at various positions during the ascent
thanks to yellow pawl, red tension spring and the gravity.
Thanks to the interaction between the green pin and the jade runway:
At the highest position of the blue plate, the pawl is separated from the pink rack.
At the lowest position of the blue plate, the pawl is brought into contact with the rack.
The spring generates a counterclockwise torque to the pawl when the plate goes up.
The spring generates a clockwise torque to the pawl when the plate goes down.
To get higher position of the plate: raise it to the desired position.
To get lower position of the plate: move it as high as possible, then move it down as
low as possible and raise it to the desired position.

STEP files of this video:
https://www.mediafire.com/file/yg4lp7...
Inventor files of this video:
https://www.mediafire.com/file/77h9mu...