A rotary-type bag transfer device including a plurality of pairs of left and right grippers provided around an intermittently rotating table. The device includes a pin extending at least partially through the interior of the housing, and a torsion spring disposed within the housing. A control circuit intermittently adjusts the angular position of the tracking device so that the mirrors face the sun. The embodiment according to the invention is suitable for large band widths and discharge projections up to 100 m and eliminates the danger of tipping over.