Abstract: A row-crop harvester has a frame displaceable in a predetermined travel direction and formed with a plurality of forwardly open throats each provided with a respective conveyor chain each in turn spanned over a respective drive sprocket. Each such drive sprocket is carried on a respective drive shaft having a drive gear that meshes with the drive gears of the conveyor chains to each side. Each drive shaft with its respective sprocket and gear are together mounted in a respective housing bolted to the frame of the harvester and having a mounting flange whose outer periphery corresponds to the pitch circle of the respective drive gear. A main gear meshing with one of the drive gears rotates all of these drive gears simultaneously, and each conveyor chain has a stretch exposed in a respective throat of the machine which is opposite the stretch of the flanking chains for backward advance of cut crop.