Patent ID: 7631825

Claim:
An apparatus for comminuting pieces of cuttable material, the apparatus comprising: a first comminuting stage for performing a pre-comminuting process; and a second comminuting stage for performing a fine comminuting process, the second comminuting stage including a comminuting system rotating about an axis of rotation to which the cuttable material is conveyed via a supply channel, wherein the first comminuting stage is integrated in the supply channel that conveys the cuttable material to the second comminuting stage, wherein the first comminuting stage includes a cutting unit having a knife, the cutting unit cutting a predetermined portion of the cuttable material in a plane that is substantially perpendicular to a conveying direction of the cuttable material in the supply channel after leaving the first comminuting stage, and wherein the cutting unit is provided with a retaining element, which is arranged in a conveying direction below and at a distance to the knife, and which can be moved into and out of the supply channel.