Two rockers (in grey and green) oscilate while the input pink gear rotates continuously.

Bevel gears have the same tooth number. The orange gear shaft has an eccentric for the grey rocker. It is case of four-bar linkage, in which the conrod (orange eccentric) is the driving link.

To slow down the rocker oscilation, the transmission ratio of bevel gear drives can differ from 1.

Move the blue slider by turning the violet screw for getting various course positions of the green rocker.

Instead of bevel gear drives, worm or helical gear ones can be used.