DUAL-SHAFT SHREDDER WITH A HORIZONTAL MAINTENANCE CONCEPT

Abstract

A two-shaft shredder includes a shredder housing, a first cutter disc unit, and a second cutter disc unit. The first cutter disc unit has at a first axial end a first bearing unit (80) with a first bearing housing and at a second axial end a second bearing unit with a second bearing housing. A first cutter disc block is rotatably mounted about a first axis of rotation. The second cutter disc unit has at a first axial end a third bearing unit with a third bearing housing and at a second axial end a fourth bearing unit with a fourth bearing housing A second cutter disc block is rotatably mounted about a second axis of rotation. The shredder housing has a first maintenance hatch cover which, in a release position, permits removal of the first cutter disc unit together with the first and second bearing units.

Claims

1-31. (canceled)

32. A two-shaft shredder for shredding solids or solids in liquids, comprising: a shredder housing defining an internal shredding chamber; an inlet opening in the shredder housing for supplying solids into the shredding chamber; an outlet opening in the shredder housing substantially opposite the inlet opening for discharging shredded solids from the shredding chamber; a first cutter disc unit comprising a first cutter disc block having a plurality of first cutter discs arranged on a first hub body such that there is a space between each two adjacent first cutter discs; a second cutter disc unit comprising a second cutter disc block having a plurality of second cutter discs arranged on a second hub body such that there is a space between each two adjacent second cutter discs; wherein the first and second cutter disc blocks are axially offset from each other with their axes of rotation such that at least some of the first cutter discs each engage a space between two adjacent second cutter discs and some of the second cutter discs each engage a space between two adjacent first cutter discs; wherein the first cutter disc unit has at a first axial end a first bearing unit with a first bearing housing, and at a second axial end a second bearing unit with a second bearing housing, in which the first cutter disc block is mounted rotatably about a first axis of rotation; wherein the second cutter disc unit comprises at a first axial end a third bearing unit with a third bearing housing, and at a second axial end a fourth bearing unit with a fourth bearing housing, in which the second cutter disc block is rotatably mounted about a second axis of rotation; and wherein the shredder housing has a first maintenance hatch cover which can assume a release position and a closed position and, in the release position, permits removal of the first cutter disc unit together with the first and second bearing units.

33. The two-shaft shredder according to claim 32, wherein the shredder housing comprises a second maintenance hatch cover which can assume a release position and a closed position and, in the release position, permits removal of only the second cutter disc unit together with the third and fourth bearing units.

34. The two-shaft shredder of claim 32, wherein the bearing units comprise seals so as to seal the bearings of the bearing units against the cutter disc blocks.

35. The two-shaft shredder according to claim 32, wherein the respective bearing housings of the bearing units can be fixed against rotation on the shredder housing in the assembled state.

36. The two-shaft shredder according to claim 32, wherein the shredder housing comprises an inlet side having the inlet opening, an outlet side having the outlet opening, and first and second end sides arranged perpendicular to the first and second axes of rotation, and first and second lateral sides, wherein the first maintenance hatch cover is arranged at the first lateral side.

37. The two-shaft shredder according to claim 32, wherein the first cutter disc unit is removable from the shredder housing in a first removal direction which is transverse to the first axis of rotation and parallel to a plane defined by the first and second axes of rotation.

38. The two-shaft shredder according to claim 32, wherein the first cutter disc unit is positively fixed to the shredder housing by means of first and second counter holders.

39. The two-shaft shredder of claim 38, wherein the first and second counter holders are concealed by the first maintenance hatch cover when the first maintenance hatch cover is in the closed position and are accessible when the first maintenance hatch cover is in the released position.

40. The two-shaft shredder according to claim 32, comprising a first parallel kinematic system for moving the first maintenance hatch cover from the closed position to the release position.

41. The two-shaft shredder according to claim 40, comprising a first lifting means engaging the first parallel kinematics for moving the first maintenance hatch cover from the closed position to the release position.

42. The two-shaft shredder according to claim 32, wherein the first and second cutter disc blocks are provided with at least one first groove into which a carrier can engage for guiding.

43. The two-shaft shredder according to claim 32, further comprising: a first drive motor, which preferably can drive the first cutter disc block via a first gear; a second drive motor, which can preferably drive the second cutter block via a second gear; and an electronic control unit for controlling the two drive motors.

44. The two-shaft shredder of claim 43, further comprising: a first coupling between the first cutter block and the first drive motor; and a second coupling between the second cutter block and the second drive motor, said first coupling having a first centering means for centering said first drive motor relative to said first cutter block, and said second coupling having a second centering means for centering said second drive motor relative to said second cutter block.

45. The two-shaft shredder of claim 44, wherein the first and second centering means each include corresponding cone portions that clampingly engage one another.

46. The two-shaft shredder according to claim 43, wherein the first and second drive motors are floating.

47. A two-shaft shredder according to claim 43, wherein the electronic control unit is arranged to control the drive motors in at least a first operating mode and in a second operating mode different from the first operating mode.

48. The two-shaft shredder according to claim 47, wherein: the electronic control unit is arranged to control the first and second drive motors in the first operating mode in such a way that the first and second cutter disc blocks are driven in opposite directions at substantially identical speeds; and the control unit is arranged to control the first and second drive motors in the second operating mode in such a way that the first and second cutter disc blocks are driven at different speeds and/or in the same direction of rotation.

49. The two-shaft shredder according to claim 43, wherein the electronic control unit is arranged to control the drive motors such that the cutter disc blocks have a low differential speed with respect to each other.

50. The two-shaft shredder according to claim 43, wherein the electronic control unit is arranged to control the drive motors such that the cutter disc blocks have alternating speeds.

51. The two-shaft shredder according to claim 43, wherein the electronic control unit is arranged to control the drive motors such that only one of the cutter disc blocks rotates while the other is stationary.

52. The two-shaft shredder according to claim 51, wherein the rotating cutter disc block rotates against a shredding direction.

53. The two-shaft shredder according to claim 43, wherein the gears are bevel gears.

54. A method for servicing a two-shaft shredder, the method comprising the steps of: moving a first maintenance hatch cover from a closed position to a release position; horizontally and laterally removing a first cutter disc unit with a first cutter disc block with a plurality of first cutter discs arranged on a first hub body in such a way that there is a space between each two adjacent first cutter discs, wherein the first cutter disc unit has at a first axial end a first bearing unit with a first bearing housing and at a second axial end a second bearing unit with a second bearing housing, in which the first cutter disc block is rotatably mounted about a first axis of rotation.

55. The method according to claim 54, wherein the steps are carried out without exposing an inlet opening and/or outlet opening and without disassembling a hopper at the inlet opening and/or an outlet pipe at the outlet opening.

56. The method according to claim 54, further comprising the step of: releasing a counter-holder before the step of removal.

57. A method for operating a two-shaft shredder comprising the steps of: driving two cutter disc blocks in a first operating mode for a first operating period; stopping the first operating mode at the end of the first operating period; and driving the two cutter disc blocks in a second operating mode for a second operating period.

58. The method of claim 57, wherein in the first mode of operation the two cutter disc blocks are driven at substantially identical speeds, and in the second mode of operation the two cutter disc blocks are driven at different speeds.

59. The method of claim 57, wherein in the first mode of operation the two cutter disc blocks are driven in opposite directions, and in the second mode of operation only one of the two cutter disc blocks is driven.

60. The method according to claim 57, further comprising the steps of: moving a side maintenance hatch cover from a closed position to a release position; and driving the two cutter disc blocks in the same direction and into the direction of the maintenance hatch cover in order to eject a foreign object.

61. The method according to claim 54, further comprising the step of: moving the first maintenance hatch cover from the closed position to the release position by means of a confirmation switch.

62. The method according to claim 57, further comprising the steps of: sensing a first power draw of a first drive motor of the first cutter block; detecting a second load pickup of a second drive motor of the second cutter block; and determine a failure of the two-shaft shredder based on the detected first and second power draws.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0057] Further advantages, features, and details of the invention will be apparent from the following description of preferred embodiments and from the drawings; these are shown in:

[0058] FIG. 1a is a perspective view of a two-shaft shredder with closed first and second maintenance hatch covers;

[0059] FIG. 2 is a perspective view of the two-shaft shredder of FIG. 1 with the first and second maintenance hatch covers open;

[0060] FIG. 3a is a detail from FIG. 1;

[0061] FIG. 3b is a detail from FIG. 2;

[0062] FIG. 4 is a schematic representation of the lateral removal of first and second cutter disc units;

[0063] FIG. 5 is a schematic view of a parallel kinematic system for moving the first maintenance hatch cover from a closed position to a release position;

[0064] FIG. 6 is a perspective view of the two-shaft shredder from FIG. 1 with the maintenance hatch cover open and the cutter disc unit in the removed state;

[0065] FIG. 7 is a perspective view of the cutter disc unit including first and second counter holders;

[0066] FIG. 8 is a cross section of the cutter disc unit shown in FIG. 7;

[0067] FIG. 9 is another detail from FIG. 1;

[0068] FIG. 10 is a perspective exploded view of a coupling;

[0069] FIG. 11 is a section through the assembled coupling of FIG. 10;

[0070] FIG. 12 is a torque support of a drive motor;

[0071] FIG. 13 is a schematic representation of a drive control of the two-shaft shredder; and

[0072] FIG. 14 is another schematic representation of a drive control of the two-shaft shredder.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0073] A two-shaft shredder 1 for shredding solids or solids in liquids has a shredder housing 2 which defines an internal shredding chamber 4. The shredder housing 2 is arranged here on a machine frame 6 which supports the shredder housing 2. On the upper side of the shredder housing 2, with reference to FIG. 1, an inlet opening 8 is formed which is provided here with a feed hopper 10. The feed hopper 10 in turn has a grate 11 to prevent excessively large objects from passing through the feed hopper 10 into the inlet opening 8. The grate 11 is optional and can likewise be omitted, for example, if larger objects are to be filled into the feed hopper 10. With reference to FIG. 1, the outlet opening 12 of the two-shaft shredder 1 is arranged on the underside and cannot be seen in detail here. The outlet opening 12 is arranged opposite the inlet opening 8 so that fluid can flow vertically through the two-shaft shredder 1 from top to bottom with reference to FIG. 1. When installed, the outlet opening 12 may be connected to a pipe or the like to discharge the shredded material.

[0074] Inside the shredding chamber 4, first and second cutter disc units 14, 16 rotate in operation and are described in further detail below with reference to FIGS. 4, 6, 7, and 8. The first cutter disc unit 14 has a first axis of rotation A1 and the second cutter disc unit 16 has a second axis of rotation A2. The axes of rotation A1, A2 are parallel to each other, but offset. In this way, individual blades of the cutter disc units 14, 16 can mesh with each other to cut material. This is known in principle.

[0075] A first drive motor 18 is provided for driving the first cutter disc unit 14, and a second drive motor 20 is provided for driving the second cutter disc unit 16. Both are controlled by a common electronic control unit 22, which is also attached here to the machine frame 6. The electronic control unit 22 will also be described in more detail later. The first drive motor 18 is equipped with a first gear 19 and is connected to the first cutter disc unit 14 via this gear. The second drive motor 20 is equipped with a second gear 21, and is connected via this to the second cutter disc unit 16. In this way, the accommodation of the first and second drive motors 18, 20 is simplified. The first and second gears 19, 21 are preferably bevel gears, but are not shown here in further detail.

[0076] As is further apparent from FIG. 1, the shredder housing 2 has an inlet side 24 at which the hopper 10 is received, and in which the inlet opening 8 is formed. The inlet side 24 is oriented substantially upward in the embodiment shown in FIG. 1. Furthermore, the shredder housing 2 has an outlet side 26 comprising the outlet opening 12, which is here the underside of the shredder housing 2. First and second drive motors 18, 20 are provided at first and second end faces 28, 30, respectively. The first and second end faces 28, 30 are arranged substantially perpendicular to the first and second axes of rotation A1, A2 and interconnect the inlet side 24 and the outlet side 26. Further, first and second transverse sides 32, 34 are formed on the shredder housing 2.

[0077] One problem that has existed with conventional two-shaft shredders is the maintenance of the first and second cutter disc units 14, 16. For example, the first cutter disc unit 14 has a first cutter disc block 40 and the second cutter disc unit 16 has a second cutter disc block 42 (see FIGS. 4 and 7). Each of the cutter disc blocks 40, 42 is provided with a plurality of cutter discs, namely the first cutter disc block 40 is provided with first cutter discs 44 (in FIGS. 7 and 8, only one of each is provided with reference signs) and the second cutter disc block 42 is provided with second cutter discs 46. The first and second cutter discs 44, 46 are each axially spaced from one another so that the cutter discs 44, 46 of the first and second cutter disc blocks 40, 42 can mesh with one another, as is basically known in the prior art, in particular, with reference to DE 20 2010 010662 U1 and WO 2018 087 398. The cutter discs 44, 46 of the first and second cutter disc blocks 40, 42 wear out over time, so that these must be maintained, or replaced. To simplify this, the invention implements a horizontal maintenance concept, which is described below.

[0078] To enable horizontal maintenance, the two-shaft shredder 1, more specifically the shredder housing 2, has a first maintenance hatch cover 50, which is preferably formed on the first transverse side 32 of the shredder housing 2. Via the first maintenance hatch cover 50, the first cutter disc unit 14 can be removed from the shredder housing 2. It may be provided that the second cutter disc unit 16 can also be removed from the shredder housing 2 via the first maintenance hatch cover 50. According to the embodiment example shown here, however, the shredder housing 2 has a second maintenance hatch cover 52, which is assigned to the second cutter disc unit 16. In the following, the first and second maintenance hatch covers 50, 52 will always be described, it to be understood that there may also be embodiments comprising only one of the maintenance hatch covers 50, 52, which then provide access to both cutter disc units 14, 16.

[0079] In FIG. 1, the first maintenance hatch cover 50 is shown in a closed position P11. The second maintenance hatch cover 52 is also in a closed position P12. In FIG. 2, however, the first maintenance hatch cover 50 is in a release position P21 and the second maintenance hatch cover 52 is also in a release position P22. In the release positions P21, P22, the first and second maintenance hatch covers 50, 52 are pivoted upwards, preferably without performing a rotation about their own axis. To enable this pivoting of the first and second maintenance hatch covers 50, 52, the two-shaft shredder 1 has a first parallel kinematic system 54 for the first maintenance hatch cover 50 and a second parallel kinematic system 56 for the second maintenance hatch cover 52. The first and second parallel kinematics 54, 56 are substantially identically configured, so that only the first parallel kinematic 54 will be described below. It should be understood that the second parallel kinematics 56 may be constructed in a manner analogous to the first parallel kinematics 54. The first and second parallel kinematics 54, 56 can be seen particularly well in FIGS. 3a and 3b, which will be referred to below. Further, the parallel kinematics 54, 56 are again illustrated in FIGS. 4 and 5. The first parallel kinematic system 54 has a first parallelogram lever 58 and a second parallelogram lever 60. The first parallelogram lever 58 is connected with a first articulation point 59a to the shredder housing 2 and a second articulation point 59b to the first maintenance hatch cover 50. The second parallelogram lever 60 is connected with a first articulation point 61a to the shredder housing 2 and a second articulation point 61b to the maintenance hatch cover 50. The first articulation points 59a, 61a of the first and second parallelogram levers 58, 60 are aligned substantially vertically one above the other and substantially above the maintenance hatch cover 50. In the closed position P11, P12, the first and second parallelogram levers 58, 60 are pivoted downwards so that the first maintenance hatch cover 50 is aligned substantially below the first and second articulation points 59a, 61a. The parallel kinematics 54 are connected to a first lifting device 62, which here comprises a first pneumatic cylinder 63. In the illustrated embodiment, the pneumatic cylinder 63 engages the first parallelogram lever 58 to pivot it about the first pivot point 59a. As a result, the first maintenance hatch cover 50 is lifted out of the closed position P11 and moved upwards so that it reaches the release position P21 shown in FIGS. 2, 3b, and 4.

[0080] The first and second parallel kinematics 54, 56 have only been described with reference to the first end face 28 of the shredder housing 2. A corresponding parallel kinematic system is also arranged on the second end face 30, so that the first and second maintenance hatch covers 50, 52 can be raised and lowered via two such parallel kinematic systems.

[0081] As can be seen in particular from FIG. 4, first and second scrapers 66, 68 are arranged on the first and second maintenance hatch covers 50, 52, which serve on the one hand to prevent non-crushed material from passing between the maintenance hatch cover 50, 52 and the corresponding cutter disc block 14, 16 during operation, and on the other hand also to keep the intermediate spaces between the first and second cutter discs 40, 44 free. The first and second scrapers 66, 68 are arranged here on the first and second maintenance hatch covers 50, 52 so that they are moved together with the first and second maintenance hatch covers 50, 52 from the closed position to the release position. In this way, the first and second cutter disc units 14, 16 are released particularly easily and extensively.

[0082] After the first and second maintenance hatch covers 50, 52 have been moved to the release position P21, P22, the first and second cutter disc units 14, 16 can basically be removed from the shredder housing 2 along first and second removal directions E1, E2 (cf. FIG. 2). In FIGS. 2 and 3b, the first and second cutter disc units 14, 16 have already been removed. Schematically, the removal of the first and second cutter disc units 14, 16 can be seen in FIG. 4 and will now be described in more detail with reference to FIGS. 4, 6, 7, 8, and 9.

[0083] The first cutter disc unit 14 is shown separately and in perspective in FIG. 7. A cross section of this first cutter disc unit 14 is shown in FIG. 8. The section in FIG. 8 is horizontal and FIG. 8 is then a top view. Even though only the first cutter disc unit 14 is shown in FIGS. 7 and 8, it is to be understood that the second cutter disc unit 16 is of identical construction and to that extent the following description also applies to the second cutter disc unit 16.

[0084] The first cutter discs 44 are arranged on a first hub body 70 and are integrally formed therewith in the embodiment shown. Accordingly, the cutter disc block 40 is formed as a so-called monolithic cutter disc block. However, this is not mandatory and also includes embodiments in which the first cutter discs 40 are connected to the first hub body 70 in a non-positive and/or positive manner. Also shown in FIG. 8 are an optional first groove 300 and an optional second groove 300 formed on the hub body 70. The grooves 300 are indicated by dashed lines, indicating that they are optional.

[0085] With reference to FIG. 8, at the left side, the first hub body 70 extends into a first stub shaft 72 that is couplable to the first transmission 19. Referring to FIG. 8, at the right side, the cutter disc block 40 includes a second stub shaft 76. The left end of the cutter disc block 40, at which the first stub shaft 72 is arranged, is received in a first bearing unit 80 and the second stub shaft 76 is received in a second bearing unit 82. Accordingly, the second cutter disc unit 16 is also formed and has a third bearing unit 84 and a fourth bearing unit 86 (cf. FIG. 4).

[0086] The first bearing unit 80 has a first bearing housing 81, the second bearing unit 82 has a second bearing housing 83, the third bearing unit 84 has a third bearing housing 85, and the fourth bearing unit 86 has a fourth bearing housing 87. The respective first and second cutter disc blocks 40, 42 are rotatably supported within the first, second, third, and fourth bearing housings 81, 83, 85, 87. By means of the first, second, third, and fourth bearing housings 81, 83, 85, 87, the first, respectively second cutter disc units 14, 16 are attached to the shredder housing 2. With reference to FIG. 8, it can be seen that a first bearing 90 in the form of a double angular contact roller bearing in an X arrangement is provided in the first bearing housing 81. A first seal 92 is provided between the bearing housing 81, which supports an outer ring of the first bearing 90, and a first bushing 91. The first seal 92 is configured here as a contacting seal and serves to seal the cutter pulley block 44 from the bearing housing 81. The inner ring of the first bearing 90 is pressed onto the first stub shaft 72, where it is frictionally secured. In addition, a nut 93 is provided to support the inner ring. The bearing housing 81 is then closed with a first bearing cover 94. The first bearing cover 94 is screwed against the first bearing housing 81 by means of screws (cf. FIG. 9). A first lubrication port 95 is further provided in the first bearing cover 94 to allow the first bearing 90 to be lubricated.

[0087] The second bearing unit 82 has a second bearing 96, which is formed here as a roller bearing and floating bearing. The outer bearing ring is again received in the second bearing housing 83, and the inner ring is pressed onto the second stub shaft 76. The second shaft journal 76 is detachably connected to the hub body 70, as already described above. A second, contacting seal 98 is disposed between the bearing housing 83 and a second bushing 97 frictionally engaged on the second shaft journal 76, which in turn seals the cutter block 40 from the bearing housing 82 to prevent fluid from reaching the second bearing 96. Closing the second bearing housing 82 is a second bearing cover 99, which in turn is secured to the second bearing housing 82 by screws. The second bearing unit 82 is formed similarly to the third bearing unit 85, such that the shape of the second bearing cover 99 corresponds to that of a third bearing cover 100 shown in FIG. 9. The third bearing cap 100 is provided with a third lubrication port 102 for lubricating bearings received therein. A similar lubrication port is also provided for the second bearing 96 and the fourth bearing (not shown).

[0088] A particular advantage of the present invention is that cutter disc units 14, 16 together with the first, second, third, and fourth bearing units 80, 82, 84, 86 can be removed from the shredder housing 2. In other words, while disassembly of the bearings themselves is not required within the shredder housing, this makes them much less susceptible to damage and also easier to maintain. To this end, the first and second bearing housings 81, 83 comprise first and second mounting surfaces 104, 106 which, on the one hand, can be brought into abutment against first and second mounting recesses 108, 110 (cf. FIG. 4) of the shredder housing 2 and, on the other hand, cooperate with first and second counter-holders 110, 112 so as to fix the first cutter disc unit 14 to the shredder housing 2. The first and second counter-holders 110, 112 are also shown in section in FIG. 8, since the section according to FIG. 8 is a view from above. In order to achieve a further seal here, first and second O-rings 105, 107 are also arranged in the first and second mounting surfaces 104, 106, which O-rings 105, 107 can be brought into contact against the first and second counter-holders 110, 112 on the one hand and against the first and second mounting recesses 108, 110 on the other hand, so as to seal the first and second bearing housings 81, 83 against the shredder housing 2.

[0089] The third and fourth bearing housings 84, 86, are similarly configured and can be inserted into third and fourth mounting recesses 114, 116 (cf. FIG. 4) and fixed therein with corresponding third and fourth mating retainers 118, 120. The first, second, third, and fourth mating retainers 110, 112, 118, 120 have mating retainer surfaces 122, 124 corresponding to the first and second mounting surfaces 104, 106 of the first and second bearing housings 81, 83. Similarly, the third and fourth mating retainers 118, 120 have such surfaces. Further, the first and second mating retainers 110, 112 each have mounting holes 126 that can be engaged by mating retainer screws 128 to secure the first and second mating retainers 110, 112 against the shredder housing 2. The same mounting holes 126 and counter-holder screws 128 are also provided for the third and fourth counter-holders 118, 120 (cf. FIG. 9). The counter-holder screws 128 and thus also the first and second counter-holders 110, 112 are concealed by the first maintenance hatch cover 150 when the latter is in the closed position P11. Similarly, the mating retainer screws 128 of the third and fourth mating retainers 118, 120 are concealed by the second maintenance hatch cover 52 when the latter is in the closed position P12. This prevents the counter-holders from being loosened even when the first and second maintenance hatch covers 50, 52 are in the closed positions.

[0090] Consequently, to remove the first and second cutter disc units 14, 16 from the shredder housing 2, the first and second maintenance hatch covers 50, 52 must first be moved to the release position P21, P22. Subsequently, the first and second counter-holders 110, 112, and third and fourth counter-holders 118, 120, respectively, must be released. Prior to this, a maintenance bracket 130 is preferably attached to the machine frame 6, as shown in FIG. 6, which prevents the corresponding cutter disc unit (in FIG. 6, the second cutter disc unit 16) from falling down after the third and fourth counter holders 118, 120 have been released. The maintenance bracket 130 is supported on the machine frame 6 and in this embodiment example has first, second, and third supports 131, 132, 133, with an optional gripper 134 provided on the second support 132. In other embodiment examples, only two carriers may be provided, or four or more carriers may be provided. The gripper 134 has a claw 135 that can circumferentially grip the cutter disc assembly 16. A pull rod 136 with handles 137a, 137b is provided on the claw 135, by means of which the claw 135 can be guided to the cutter disc unit 16. As long as the cutter disc unit 16 is still arranged within the shredder housing 2, it should be gripped by means of the claw 135. It can then be pulled out of the shredder housing 2 via the pull rod 136, resting on the first, second, and third struts 131, 132, 133. The cutter disc block 40 may be provided with the first groove 300, as shown in FIG. 8. The width of the grooves 300 is preferably slightly wider than the width of the struts 131, 132, 133. The struts 131, 132, 133 are positioned below the cutter disc assembly 16 such that grooves 300 and struts 131, 132, 133 can interlock. The grooves 300 allow the cutter disc unit 16 to be positioned axially above the supports 131, 132, 133. The cutter disc unit 16 can be rolled out of the shredder housing 2 along the supports 131, 132, 133, for example, manually, with the cutter disc unit 16 resting on the first, second and/or third supports 131, 132, 133 and being guided over the grooves 300, so that the axial positioning of the cutter disc unit 16 is maintained even during rolling out. This has the advantage that the position of the bearing housings 81, 83 is maintained in the axial direction with respect to the axis of rotation or is fixed by the grooves 300. From here, the cutter disc unit 16 can then be transported, for example, with the aid of a crane. Preferably, the first and second cutter disc units 14, 16 are inserted back into the shredder housing 2 in an analogous manner. This enables simple and safe maintenance on the one hand and minimizes the risk of injury on the other.

[0091] The first and second cutter disc blocks 40, 42 of the first and second cutter disc units 14, 16 are connected to the first and second drive motors 18, 20 via first and second couplings 200, 202, as illustrated in FIG. 10 and FIG. 11. Of these couplings 200, 202, only one is described below, namely the first coupling 200 by way of example. Identical designs preferably apply to the second coupling 202, but it may also be of a different or similar design.

[0092] In the embodiment shown, the first and second cutter disc blocks 40, 42 are connected to the first and second drive motors 18, 20 via the first and second gearboxes 19, 21, even though gearboxes are not essential and the drive motors 18, 20 could also be coupled directly to the cutter disc blocks 40,42.

[0093] The first gearbox 19 has a first output shaft 204, which is provided with a first clutch disc 206 at its distal end. The first clutch disc 206 has a first cone portion 208 (see FIG. 11), which is formed here as a male cone. A second clutch disc 210 is non-rotatably seated on the shaft journal 72. Both the first clutch disc 206 and the second clutch disc 210 are provided with a plurality of through holes, so that they can be clamped against each other by means of clutch screws 212. A centering cup 214 is provided to center the first clutch disc 206 against the second clutch disc 210, thereby centering the output shaft 204 against the shaft journal 72. The centering cup 214 also has through holes so that it can be clamped against the first and second clutch discs 206, 210, preferably by means of the clutch screws 212. The centering cup 214 has its collar 216 seated on a radial centering surface 218 of the second clutch disc 210 and its base 220 engaging behind the first clutch disc 206. A second cone portion 222 is formed on the centering cup 214 between the collar 216 and the base 220 and corresponds with the first cone portion 208 and can cooperate therewith for centering. Thus, when the coupling screws 212 are tightened, the second cone portion 222 is pressed against the first cone portion 208 and thus the first coupling disc 206 is centered on the centering cup 214.

[0094] In order to additionally center the second clutch disc 210 on the shaft journal 72, a first conical ring 224 is provided in this embodiment, which extends with a first conical projection 226 between the first clutch disc 210 and the shaft journal 72, as well as a second conical ring 228, which extends with a second conical projection 230 between the first clutch disc 210 and the shaft journal 72, and is arranged opposite the first conical ring 224. The two cone rings 224, 228 are braced against each other by eyebolts 232. In this way, the second clutch disc 210 is centered on the shaft journal 72. Furthermore, the output shaft 204 is also aligned in this way with respect to the shaft journal 72. Thus, both angular errors and radial misalignment are compensated.

[0095] FIG. 10 and FIG. 12 now illustrate a drive bearing of the drive motor in detail. The first drive motor 18 is supported on the machine frame 6 via a first drive bearing 240 (cf. FIG. 1), and the second drive motor 20 is supported on the machine frame 6 via a second drive bearing 242. Only the first drive bearing 240 is explained below, although identical explanations preferably also apply to the second drive bearing 242.

[0096] The first drive bearing 240 includes a first torque support 244 and a second torque support 246. The first drive bearing 240 is designed as a floating bearing and does not center the first drive motor 18 and the first gearbox 19 relative to the first cutter block 40; this is achieved via the first coupling 200 as described above. In operation, the first and second torque supports 244, 246 preferably serve solely to support torques. They may also be configured to partially support weight forces in order to partially relieve the load on the bearings of the cutter disc blocks. When the first and second couplings 200, 202 are open, the first and second torque supports 244, 246 fully absorb the weight force of the first and second drive motors 18, 20, and, if applicable, of the first and second gears 19, 21. Therefore, they will slightly move down a little bit.

[0097] Here, the first torque support 244 includes a first damper arrangement 250 to support torques in a first direction of rotation and a second damper arrangement 252 to support torques in a second opposite direction of rotation. The second torque support 246 includes first and second damper arrangements, which are similar to each other (not shown, see FIG. 10). Each damper arrangement 250, 252 here also comprises two rubbers attached to a cross member 254. The cross member 254 is in turn attached via first and second support plates 256, 258 to a first gear housing 260, which in turn also supports the first drive motor 18.

[0098] The first and second drive motors 18, 20 can be independently controlled by the electronic control unit 22. This allows the two-shaft shredder 1 to be operated in two or more modes of operation. For example, in a first mode of operation, the first and second cutter disc blocks 40, 42 are controlled to rotate in the same direction, at substantially identical speeds. Then, in a second mode of operation, the drive motors 18, 20 are controlled by the control unit 22 to drive the first and second cutter disc blocks 40, 42 at different speeds and/or in the same direction of rotation. FIG. 13 illustrates such a scenario. The horizontal axis is the time axis, and speed n is identified on the vertical axis. At time t0, the first cutter block 40 is driven at a speed n1 that is higher than the speed n2 at which the second cutter block 42 is driven. At a time t1, the electronic control unit 22 then starts to reverse and accelerates the second cutter disc block 42 until it reaches the first speed n1 at the time t2. At the same time, the first cutter disc block 40 is slowed down at time t1 until it has the lower speed n2 at time t2. After a predetermined period of time, which lies between the second time t2 and a third time t3, the two-shaft shredder 1 continues to operate. At time t3, the first cutter disc block 40 is then again accelerated, starting from speed n2 to speed n1, which the latter reaches at time t4. At the same time, the second cutter disc block 42 is decelerated to reach the second speed n2 again at time t4. Additional similar periods may follow. This operating mode has the advantage that there is a relative movement between the first and second cutter disc blocks 40, 42, so that they “scratch each other free,” i.e., any elements adhering in gaps between individual cutter discs are conveyed out.

[0099] FIG. 14 shows a further operating mode in which foreign bodies 200 are conveyed out of the comminution chamber 4. If foreign bodies 200, which cannot be crushed despite the grate 11 (cf. FIG. 1), get into the crushing chamber 4, they cannot reach the outlet opening 12 because they cannot be crushed and are retained on the other side by the rakes 66, 68. In order to now automatically convey these foreign bodies out of the size reduction chamber, it is preferred to open one of the maintenance hatch covers 50, 52, in FIG. 11 the second maintenance hatch cover 52. Subsequently, both cutter disc blocks 40, 42 are rotated in the direction of the opened maintenance hatch cover, in this case in a clockwise direction of rotation. In this way, the foreign bodies 200 are moved by the cutter disc blocks 40, 42 in the direction of the opened maintenance hatch cover 52 and thus fall out of the shredder housing 2.

[0100] In such an operating mode, it is important to take appropriate safety measures for operating personnel to prevent injury to the then laterally exposed cutter block. For example, it may be stipulated that such operation may only be carried out in a closed room.

[0101] Other such operating modes are conceivable and preferred, and have been described above. It is preferred to store such operating modes in the electronic control unit 22, preferably on a memory provided there. For this purpose, the electronic control unit 22 preferably has an operating panel 202 (cf. FIG. 1) via which an operator can operate the two-shaft shredder 1.