This wonderful mechanism is similar in principle to the planetary reducer, but instead of the regular spur gears it employs bevel ones, and the gears in the middle are tilted. When projecting the pitch cones of these bevel gears on a vertical plane, their triangular outlines combine to create an isosceles trapezoid that is completely filled.

The gear ratio for this particular model is 4:1. The model's diameter in its widest part is 20 cm (7 7/8").

To download .stl files for this model, please visit http://otvinta.com/download18.html.