peripheral sorting rollers 3 fig6 shows a different perspective view of the detail of the device for sorting which has already been shown in fig5 the material is introduced in the direction indicated by the arrow bearing the reference sign 6 the undersize grain leaves the sorting surface 17 in the direction indicated by the arrow bearing the reference sign 9 the oversize grain leaves the sorting surface 17 in the direction indicated by the directional arrow 10 fig7 shows the sorting surface 17 in a plan view the two regions which respectively comprise helical rollers 3 exhibiting different rotary directions and different coiling directions of their helices 4 can in particular be seen fig8 shows a cross sectional representation of the detail which has already been shown in fig5 to 7 it clearly shows how the helices 4 of the helical rollers 3 interlock the receptacles 24 for pivotally mounting and also the drives 22 23 are also indicated fig9 shows a digger 39 s scoop 26 comprising a device 1 for sorting in accordance with the invention the digger 39 s scoop comprises helical rollers 3 which are mounted at one end and each provided with a helix 4 the sorting material is introduced into the digger 39 s scoop via the filling opening 28 which is provided with teeth 27 the digger 39 s scoop comprises a lateral opening 29 for expelling the oversize grain which is different from the filling opening the oversize grain leaves the device for sorting via this lateral expelling opening 29 as indicated by the directional arrow 10.