The mechanism gives long stroke length of orange slider L = 4R.
R is crank radius (in pink) and length of conrod (in green).
If the crank is driving, the mechanism faces unstable positions when the crank rotary axis and the slider pivot are in line.
To fix this problem here the mechanism is added with a chain drive to make the conrod driving. The yellow transparent part represents a chain.
Grey sprocket of Z2 teeth is stationary. Green sprocket of Z1 teeth is fixed to the green conrod. Z2 = 2.Z1.
So the mechanism has two driving links: the crank and the conrod that rotate synchronically.
If L differs from R, the mechanism does not work.