An embodiment of Pin Couplings 3 when:

- R1 is different from R2

- pins radius are larger than shafts radius

The working surface of the blue shaft is created when a circle of radius 10 (in the plane perpendicular to the shaft axis, its center is 5 from the shaft axis) moves along a helix of pitch 20. The working surface of the pink shaft is created similarly by a circle of radius 15 (in the plane perpendicular to the shaft axis, its center is 5 from the shaft axis) moving along a helix of pitch 20. Distance between the shafts is 25.

Transmission ratio is 1. The mechanism now looks like a gear drive but the two shafts rotate the same direction.