This mechanism comprises of three bevel gears and two spur gears. The bevel gear near to the input crank is served as the frame and the other gears are all movable. When inputting a rotation from the crank, the bigger spur gear will be rotated and the middle bevel gear whose axis is set on the circle of the wheel of the bigger spur gear will rotate about its own axis and revolve about the axis of input crank. Besides, the smaller spur gear will be driven by the bigger spur gear.