Crank for Small Angle Rotation

Input: green crank of Ng velocity.
Output: pink shaft of Np velocity.
Yellow gear is kept immobile.
Blue and violet gears are fixed each to other.
Tooth numbers of the pink, yellow, blue and violet gears:
Zp = 20, Zy = 19, Zb = 20 and Zv = 19 respectively.
Ng/Np = (Zp.Zb) / ( Zp.Zb – Zv.Zy) = 10.26
The ouput rotates around 10 times slower than the input in the same direction.