circumferentially measured dimension is designated at d preferably the teeth of the toothed discs are arranged on the cylindrical roller core in a screw thread like fashion this ensures that adjacent teeth extend into the bale surface in succession fig4 illustrates helical toothed disc 8 having four teeth 9 the thickness of the disc 8 is designated at c the axial offset between the open ends 8 39 8 34 of the toothed disc 8 is designated at b fig5 a illustrates schematically a bale opening device which has two opening rollers 4 and 4 39 the arrows c c 39 indicate the direction of rotation of the opening rollers 4 4 39 the tips of the teeth 9 are oriented in the direction of rotation the grate 3 extends underneath the opening rollers 4 and 4 39 and may pivot about supports 3b the arrows d and d 39 indicate successive operating directions in the two directions of motion fig5 b schematically shows the two opening rollers 4 and 4 39 in top view indicating the course of the toothed discs 8 of the opening roller 4 and the toothed discs 8 39 of the opening roller 4 39 the helical course of each toothed disc is effected by bending the discs in an s or z form about each toothed disc visible in fig5 b there is circumscribed a rectangle indicated in dash dot lines to designate the zone within which the respective discs 8 and 8 39 engage into the upper surface of the bale.