Yellow base and yellow gear are stationary.
Blue frame to which blue rack is fixed has prismatic joint with the grey lever.
Green frame to which green rack is fixed has prismatic joint with the glass frame.
When turning the frame to which grey rack is fixed, the blue and green frames stretch out. The green moves twice faster than the blue thanks to red gear that has revolution joint with the blue frame.
Stroke length S of the blue frame:
S = 2(α/360)(mZyPi)
α: rotary angle of the grey carrier (deg)
m: module of the yellow gear
Zy: tooth number of the yellow gear
Pi = 3.142
To increase stroke length of the green frame it is possible use other mechanisms: lazy tongue, cable, …