Device for preparation of straw materials

A device in a grass-matting machine for breaking up straw material said device including an inlet (10) receiving cut straw material, an outlet (11) through which broken up straw material is discharged, a relatively large diameter central roll (5), a plurality of relatively small diameter planetary rolls (6, 7) spaced at predetermined radial distances from said central roll (5) and spaced at circumferentially spaced distances from one another around a portion of the circumference of said central roll (5) between said inlet (10) and said outlet (11), every other one of said planetary rolls having a drive wheel on its end at one lateral side of said machine and each of the other of said planetary rolls having a drive wheel on its end at the other lateral side of said machine, a drive (13, 14) operative to rotate said central and planetary rolls, said planetary rolls (6, 7) being rotated in a direction opposite to the direction in which said central roll is rotated, said drive including a first drive means in driving engagement with said drive wheels on said every other one of said planetary rolls and a second drive means in driving engagement with said drive wheels on said other of said planetary rolls, a brush roll (8) positioned below said central roll and a frame (15) including side walls (16, 17) supporting said rolls (6, 7) at their ends to thereby form an assembly, said planetary rolls having a surface structure matching the surface structure of said central roll.