A device for dividing a flow of lumpy material into two sub-flows comprises a dividing mechanism which comprises a dividing edge for splitting the material flow into two sub-flows, an apparatus for directing the material to the dividing mechanism and an apparatus for diverting the two sub-flows away from the dividing mechanism. The dividing edge can be moved back and forth in its longitudinal direction following its own track. Embodiments of the device can permit the wear on the dividing edge to be more evenly distributed and the service life of the device may thereby be increased.