i = n1/nc = 1 – ((Z2.Z4)/(Z1.Z3))
n1: velocity of the green internal gear, its tooth number Z1 = 44
nc: velocity of the blue crank.
Z2 = 24 (yellow gear); Z3 = 20 (pink gear); Z4 = 40 (fixed orange internal gear). The yellow gear and the pink one are fixed together.
Z1 - Z2 = Z4 – Z3
i = -1/11
The crank, the green gear rotate in opposite directions for this case.