تماشای ویدئو Parallelogram mechanism with gears 1 از آی-ویدئو
The red gear (teeth number Z2) is fixed with the blue connection rod.
The green gear has internal teeth number Z1.
Velocity relation: ω1 = ωc.(1-Z2/Z1)
ω1: velocity of Z1
ωc: velocity of the violet crank.