Double shaft shredder with horizontal maintenance solution

Abstract

The invention relates to a double-shaft shredder (1) for shredding solids or solids in a liquid, comprising a shredder housing (2), a first cutter block unit (14) and a second cutter block unit (16). The first cutter block unit (14) has a first bearing unit (80) with a first bearing housing (81) on a first axial end and a second bearing unit (82) with a second bearing housing (83) on a second axial end, a first cutter block (40) being rotatably mounted in the first and second bearing units about a first axis of rotation (A1). The second cutter block unit (16) has a third bearing unit (84) with a third bearing housing (85) on a first axial end and a fourth bearing unit (86) with a fourth bearing housing (87) on a second axial end, a second cutter block (42) being rotatably mounted in the third and fourth bearing units about a second axis of rotation (A2). The shredder housing (2) has a first maintenance flap (50) which can assume a release position (P21) and a closed position (P11) and in the release position (P21) allows the first cutter block unit (14) together with the first and second bearing units (80, 82) to be removed.

Description

TECHNICAL FIELD

[0001] The invention relates to a double shaft shredder for shredding solids or solids in a liquid, comprising a shredder housing defining a shredding space inside, an inlet opening in the shredder housing for feeding solids into the shredding space, an outlet opening in the shredder housing substantially opposite the inlet opening for leading shredded solids out of the shredding space, a first cutterhead unit having a first cutterhead block with a plurality of first cutterheads arranged on a first hub such that between two adjacent first cutterheads there is respectively an intermediate space, a second cutterhead unit having a second cutterhead block with a plurality of second cutterheads arranged on a second hub such that between two adjacent second cutterheads there is respectively an intermediate space, wherein the first and second cutterhead blocks are axially offset with respect to each other with their axes of rotation, so that at least some of the first cutterheads respectively engage into the intermediate spaces between two adjacent second cutterheads and some of the second cutterheads respectively engage into the intermediate spaces between two adjacent first cutterheads. BACKGROUND

[0002] The double shaft shredder of this design is used for shredding solids, such as organic matter, such as animal carcasses, branches, twigs, plants or other materials, such as plastic waste or generally recycling material. The solids to be shredded can be supplied in dry form or in the form of a liquid stream through the inlet opening into the double shaft shredder.

[0003] For efficient shredding, the double shaft shredder has two shafts on each of which a plurality of cutterheads are arranged and which are referred to as cutterhead blocks. The cutterheads engage alternately into each other, which is achieved and achieved by the fact that between two adjacent cutterheads of one cutterhead block there is an axial distance which is greater than the thickness of the cutterheads of the other cutterhead block and the axes of the two cutterhead blocks are spaced apart from each other by less than the diameter of one cutterhead.

[0004] The two cutterhead blocks of the double shaft shredder are usually driven in opposite directions and for this purpose are coupled to each other, for example by means of a respective drive mechanism. Especially when the two cutterhead blocks are rotated at different rotational speeds, a good shredding result can be achieved. In this way, high shearing and tearing forces are caused by the counter-rotating cutterheads in the intermediate spaces between the two cutterhead blocks, which lead to efficient shredding of the solids. In addition, the different rotational speeds result in other cutter segments of adjacent cutterheads engaging into each other in each revolution, thereby automatically cleaning the cutterheads from adhering shredded material.

[0005] The disadvantage of a two-shaft shredder of this construction type is that, due to the form of movement of the two shafts and the knife discs arranged thereon relative to one another, the knife discs can be damaged if a hard solid enters the shredding space and becomes jammed between the two knife discs or between a knife disc and the oppositely arranged shaft. As a result, the knife discs can be severely damaged in the region of their cutting edges, so that the two-shaft shredder can no longer continue to operate or can only operate with low shredding efficiency. Depending on the type and quantity of the material to be shredded, wear can also occur at the knife discs.

[0006] It is known for this reason that two-shaft shredders are equipped with a quick-change system, in which the knives can be pulled off the shafts in order to replace such damaged knives. This enables the function of the two-shaft shredder to be restored with little maintenance outlay.

[0007] Another system known from WO2018087398 uses a monolithic knife disc block, in which the individual knives are integrally connected with the shaft or hub. On the axial end, a journal is embedded, so that the knife disc block can thus be replaced as a whole simply and quickly.

[0008] Monolithic knife disc blocks are known from DE202010010662U1.

[0009] A two-shaft shredder with a quick-change device is known from EP3248687. It is provided there that the two knife shafts each have an axial recess on one side and a journal on the other side, so that they can be removed through the entry opening after the particular end-side part has been detached. In particular, the entire motor block is removed from the end side. This constitutes a not insignificant outlay, since in particular the introduction funnel and the like must be removed in order to be able to replace the knife shafts.

[0010] DE202012007418U1 discloses a shredding device in which individual knives can be replaced by means of a lateral flap which can be opened like a door about a vertical axis. The knives are arranged on the shafts for this purpose in such a way that they can be easily replaced. However, there are no encircling knives. The solution cannot therefore be transferred without problems to a knife disc shaft or a knife disc block as described above.

[0011] Another two-shaft shredder is known from US5,580,009B1. The two-shaft shredder disclosed there is driven via a motor and a transmission, so that the two knife shafts rotate in opposite directions with a fixed speed ratio. The shafts are connected with the respective bearing unit or drive unit by means of a shaft connector, which can be detached. Wall elements can be removed at the side of the shredder housing in order to be able to replace the knife shafts in this way. A disadvantage here is in particular the shaft connection, which entails certain disadvantages in terms of strength.

[0012] Furthermore, EP 2 846 918 B1 discloses a maintenance-friendly two-shaft shredder, wherein the fill hopper together with a part of the knife shaft bearing can be flipped open, so that the knife shaft can be accessed from above. The knife shaft can then be released by loosening a special bearing plate from the housing. The knife shaft can then be taken out upwards and replaced with a new or different knife shaft. The fill hopper together with the bearing housing is then closed again. The disadvantage here is again that the fill hopper has to be folded up. For this reason, the two-shaft shredder disclosed here is not suitable for installation variants in which, for example, a pipeline is provided instead of the fill hopper, or for two-shaft shredders in which the fill hopper is fixed in a different way and cannot be detached without problems.

[0013] Further two-shaft shredders are known, for example, from EP 3 566 777 A1, DE 10 2007 049 028 A1, US 2014 010 3152 A1, EP 2 662 143 A2, DE 43 15 671 A1, EP 3 453 460 A1 and EP 2 736 645 A1. SUMMARY

[0014] The task of the present application is to provide a two-shaft shredder of the type mentioned at the outset, which is improved in terms of maintenance and / or wear or service life. In particular, the two-shaft shredder should be operator-friendly, time-saving in terms of maintenance and preferably prevent malfunctions.

[0015] The task is solved in a first aspect by a two-shaft shredder. The two-shaft shredder is therefore characterized in that the first cutterhead unit has a first bearing unit with a first bearing housing on a first axial end and a second bearing unit with a second bearing housing on a second axial end, the first cutterhead block being rotatably supported in the first bearing unit and the second bearing unit about a first axis of rotation. The second cutterhead unit has a third bearing unit with a third bearing housing on a first axial end and a fourth bearing unit with a fourth bearing housing on a second axial end, the second cutterhead block being rotatably supported in the third bearing unit and the fourth bearing unit about a second axis of rotation. The shredder housing has a first maintenance flap, which can assume a release position and a closed position and in the release position allows the first cutterhead unit together with the first and second bearing units to be taken out.

[0016] According to this first aspect, the application is based on two basic recognitions: On the one hand, the inventors have recognized that it is advantageous to configure the cutter block unit, which comprises a cutter block and two bearing units, as a structural unit that can be removed from the device as a whole or in its entirety. In this way, the problem of the support structure of the cutter block can be avoided. These bearing units each have a bearing housing, which can be connected to and secured on the shredder housing. Thus, when replacing or exchanging the cutter block, it is not necessary to also disassemble the bearings of the cutter block. Rather, the bearings are removed directly and completely together. This also makes the bearings themselves easier to maintain. In the prior art solutions, such as the detachable shaft mentioned at the outset, the bearings remain in the shredder housing and only the shaft and the knives are replaced. This makes the maintenance of the bearings more difficult, which in turn requires almost complete disassembly of the entire two-shaft shredder. In order to avoid this, according to the application it is proposed to remove the first and second bearing housings together with the cutter block.

[0017] A second basic idea of the application is that a first maintenance flap is provided, which allows the removal of the cutter block unit. Thus, for example, it is not necessary to remove the fill hopper or the like or the lines at the discharge opening in order to remove the first cutter block unit. Rather, the first maintenance flap provides access to the shredder housing, so that the first cutter block unit can be removed.

[0018] The first and second cutter block units can here be configured as is known from DE 20 2010 010 662 U1, i.e. in particular as monolithic cutter blocks. In this case, the cutter is configured in one piece or as a unit with the respective hub. Thus, in the context of the present disclosure, the term "hub" is not to be understood strictly as a shaft / hub connection, but rather, in contrast, defines an area that is internal in relation to the cutter. However, the cutter block unit can also consist of a shaft together with individual knives that are detachably secured on the shaft, as is also known from the prior art. Hybrid forms or other configurations are also conceivable and preferred. However, monolithic cutter blocks are particularly preferred, which have a journal that rotates directly on the respective internal shaft, which is received in the first and second bearing units. In this embodiment, the monolithic cutter block and the internal shaft are configured in one piece and are made from a semi-finished product. This achieves a particularly high stiffness of the cutter block and simple manufacture.

[0019] According to the application, it can be provided that the first maintenance flap only allows the removal of the first cutter block unit. That is to say, only the first cutter block unit can be removed when the maintenance flap has been brought from the closed position into the release position. However, it can also be provided that the first maintenance flap allows the removal of the second cutter block unit as well. In the release position of the first maintenance flap, this allows not only the first cutter block unit, but also the second cutter block unit, to be removed. This can achieve particularly simple and comprehensive maintenance.

[0020] However, in the first preferred embodiment, the shredder housing has a second maintenance flap which can assume a release position and a closed position and which, in the release position, allows the second cutter block unit to be removed together with the third and fourth bearing units. Thus, preferably, only the first cutter block unit can be removed by means of the first maintenance flap, and only the second cutter block unit can be removed by means of the second maintenance flap. Thus, in order to remove the first cutter block unit, the first maintenance flap is brought from the closed position into the release position, and in order to remove the second cutter block unit, the second maintenance flap is brought from the closed position into the release position. Thus, each cutter block unit is assigned one own maintenance flap. It is thereby possible to open only the maintenance flap which is assigned to the cutter block unit to be maintained. If, for example, two cutter block units are accessible by means of a single maintenance flap, it is accordingly necessary to remove the cutter block unit which is located in front in order to maintain the cutter block shaft which is located behind.

[0021] Preferably, each bearing unit, i.e. the first, second, third and fourth bearing unit, comprises a seal in order thereby to seal the bearing of the bearing unit with respect to the cutter block. The bearing of the bearing unit, which is usually configured as a ball bearing, roller bearing or the like, must be protected from water entering into the bearing from the shredding space. For this purpose, the seal is provided. The seal is also part of the bearing unit and is arranged within the respective bearing housing. That is, when the cutter block unit is removed, the seal is also removed from the shredder housing together, so that it can also be replaced or maintained. Furthermore, there is no risk of damaging the respective seal when only the cutter block is removed from the shredder housing. Thereby, the maintenance and service life of the double-shaft shredder are improved. The bearing housing, including the bearing and the seal, is arranged on the end side of the cutter block, where an integrated bearing and seal concept is formed which allows particularly easy maintenance.

[0022] Preferably, in the installed state, the respective bearing housing of each bearing unit can be fixed against rotation on the shredder housing. In this way, the bearing unit also serves to fix the cutter block unit on the shredder housing. For example, the bearing unit can be fixed on the shredder housing by means of a threaded connection and / or a clamping connection.

[0023] Preferably, the shredder housing comprises an intake side with the intake opening, a discharge side with the discharge opening and first and second end sides arranged perpendicular to the first and second rotation axes. Furthermore, the shredder housing preferably has a first lateral side and a second lateral side. The shredder housing is thus preferably essentially cuboid-shaped. The first maintenance flap is preferably arranged on the first lateral side and the second maintenance flap is arranged on the second lateral side. In this way, it becomes particularly clear that it is not necessary to remove or dismount other attached elements on the shredder housing, such as in particular a peripheral device at the intake opening, a peripheral device at the discharge opening or a peripheral device on the end sides, in order to remove the first and second cutter disc units from the shredder housing. Thereby, the maintenance is greatly simplified. It has turned out that a dual-shaft shredder, when installed into a facility, is usually provided with peripheral devices or peripheral attachments not only on the intake side but also on the discharge side, which cannot be removed without problems. By arranging the maintenance flaps on the lateral sides, a particularly easy maintenance is achieved. The shredder housing is here preferably oriented such that the rotation axes of the first and second cutter disc units are oriented horizontally. The first and second cutter disc units can then be removed perpendicular to their rotation axes but parallel to the plane formed by the two rotation axes. This is in turn particularly simple, since for this purpose, for example, a lifting car or the like can be provided in order to remove the cutter disc units from the shredder housing and to maintain them.

[0024] In a preferred extension, the first cutter disc unit is fixed to the shredder housing by means of a first and a second counter-keeping form-lockingly. In a corresponding manner, the second cutter disc unit is preferably also fixed to the shredder housing by means of a third and a fourth counter-keeping form-lockingly. The first and second counter-keeping or the third and fourth counter-keeping can be fixed to the shredder housing, for example, such that the respective bearing housing is held force-fittingly there between the counter-keeping and the shredder housing. The counter-keeping serves on the one hand to provide sufficient stability for the first and second cutter disc units, but at the same time to prevent a loss when the first and second maintenance flaps are in the release position. In this embodiment, the first and second maintenance flaps do not provide for absorbing forces or supporting or holding the first and second cutter disc units relative to the shredder housing. Lateral forces and moments can be supported by the first, second, third and fourth counter-keeping and also by a screw connection structure additionally provided between the respective bearing housing and the shredder housing.

[0025] The first and second counterpart holders are preferably covered by the first maintenance flap when the first maintenance flap is in the closed position. In the release position of the first maintenance flap, the first and second counterpart holders are preferably released. In this way, on the one hand the securing elements of the counterpart holders can be protected, and on the other hand it is prevented that the first and second counterpart holders are detached when the first maintenance flap is in the closed position. This is likewise preferably also the case for the second maintenance flap. Thus, when the second maintenance flap is in the closed position, the second maintenance flap preferably covers the third and fourth counterpart holders. In the release position of the second maintenance flap, the second maintenance flap preferably releases the third and fourth counterpart holders.

[0026] Preferably, a first parallel movement mechanism is provided for bringing the first maintenance flap from the closed position into the release position and vice versa. The parallel movement mechanism allows, for example, the first maintenance flap to be lifted without the maintenance flap being rotated about its own axis. It has been found that such a parallel movement mechanism is well suited for bringing the maintenance flap from the closed position into the release position. In the prior art, solutions are known in which the maintenance flap is pivoted about a hinge in the manner of a door. However, it is not possible here to also provide a scraper on the maintenance flap. The maintenance flap can be lifted relative to the shredder housing by means of the parallel movement mechanism, so that the scraper can be fixed on the maintenance flap without problems, since the maintenance flap is only moved parallel to the knife plate even when the maintenance flap is open. At the same time, in the release position, the maintenance flap releases a large area which can be very easily accessed. This is likewise preferably also the case for the second maintenance flap, for which a second parallel movement mechanism can be provided. The first and second parallel movement mechanisms are preferably identically configured.

[0027] Furthermore, it is preferably provided that a first lifting device acts on the first parallel movement mechanism in order to bring the first maintenance flap from the closed position into the release position. The first lifting device is preferably configured as a hydraulic device, a pneumatic device, a screw drive or an electromagnetic drive. The lifting device can preferably act with a force or a support force, so that the operator can more easily bring the first maintenance flap into the release position. This is likewise preferably the case for the second maintenance flap, for which a second lifting device is preferably provided.

[0028] Preferably, at least one of the first and second knife plate blocks, preferably both, is / are respectively provided with at least one first slot. The first slot is preferably configured as a circumferential slot and extends perimetrically about the axis of rotation of the respective knife plate block. The first slot is preferably provided between two adjacent knives of the respective knife plate block. Preferably, a second slot is respectively provided at an axial distance from the first slot. The slots can be used to guide the respective knife plate block on a carrier when the respective knife plate block is removed from the shredder housing. Such a carrier can then be fixed on the shredder housing for removing the first and / or second knife plate block.

[0029] In a second aspect of the present application or in a preferred extension of the double shaft shredder according to the first aspect of the present application, the double shaft shredder further comprises a first drive motor which preferably can drive the first cutter block via a first transmission mechanism, a second drive motor which preferably can drive the second cutter block via a second transmission mechanism, and an electronic control unit for controlling the two drive motors. The provision of two electric motors allows the first and second cutter blocks to be driven independently and thereby allows the double shaft shredder to be operated in different operating modes. The drive motors can be configured in any way, for example as electric motors, hydraulic motors, etc.

[0030] Preferably, a first coupling device is provided between the first cutter block and the first drive motor or the first transmission mechanism, and a second coupling device is provided between the second cutter block and the second drive motor or the second transmission mechanism. The first coupling device preferably has a first centering device for centering the first drive motor or the first transmission mechanism relative to the first cutter block, and the second coupling device preferably has a second centering device for centering the second drive motor or the second transmission mechanism relative to the second cutter block. The first and second centering devices are preferably self-centering. When the first and second cutter units are removed from the double shaft shredder, the first and second coupling devices can preferably be uncoupled in order to uncouple the cutter blocks from the first and second drive motors or the first and second transmission mechanisms. The first and second coupling devices are preferably rigid coupling devices. The first and second centering devices are preferably also provided for aligning or orienting the first and second cutter blocks and the first and second drive motors or transmission mechanisms. Thereby, in addition to the radial offset, angular errors can also be compensated for and the respective elements can be aligned with one another.

[0031] The first and second centering devices preferably each have a conical section which corresponds to one another and which engages into one another in a clamping manner. The first and second centering devices are preferably engaged into one another in such a way that self-centering is possible. For example, a female conical portion is provided on the transmission mechanism output shaft or the motor output shaft, and a male conical portion is provided on the respective shaft end of the cutter block. Preferably, the conical angle is chosen here in such a way that self-locking does not occur.

[0032] Furthermore, preferably the first and second drive motors are floatingly supported. The first and second drive motors are preferably supported on the shredder housing or on the frame. When the first and second coupling devices are closed, the drive motors are preferably carried by the first and second cutter block units and are supported transversely to the respective rotational axis. Preferably, the first and second drive motors, if possible together with the first and second transmission mechanisms, are supported via the first and second torque supports. However, the first and second torque supports are not used to center the first and second drive motors and / or transmission mechanisms. Only when the first and second coupling devices are disengaged, the first and second torque supports preferably also carry the respective weight of the first and second drive motors, if possible together with the respective weight of the first and second transmission mechanisms. Thereby, the assembly and disassembly of the cutter block units is significantly simplified. There is no need to separately install or dismount the drive motors and to center them with respect to the cutter block units as in the prior art. Instead, only the coupling devices have to be opened or closed, and all this thereby uncouples or couples the drive motors with the cutter blocks and simultaneously centers them.

[0033] In another preferred embodiment, the electronic control unit is connected with the first drive motor, wherein the electronic control unit is configured to control the drive motors at least in a first operating mode and in a second operating mode different from the first operating mode. The first and second operating modes are preferably different in terms of the rotational direction, rotational speed, torque, rotational speed change and / or drive profile of the first and second cutter blocks.

[0034] Preferably, the electronic control unit is connected with the first drive motor in order to supply the first drive motor with electrical energy and preferably to determine a first current consumption of the first drive motor, and the electronic control unit is connected with the second drive motor in order to supply the second drive motor with electrical energy and preferably to determine a second current consumption of the second drive motor.

[0035] Preferably, the electronic control unit is further configured to control the drive motors in the first operating mode such that the cutter blocks are driven in opposite directions at substantially the same rotational speed, and in the second operating mode such that the cutter blocks are operated at different rotational speeds and / or are driven in the same rotational direction.

[0036] According to a second aspect, the invention is based on the insight that it is particularly advantageous to provide two drive motors which can be operated independently of one another. In this way, different rotational speeds, which can also be variable, can be provided without problems and different operating modes can be carried out. In the prior art, double-shaft shredders are usually driven by one single drive motor, the cutter block being coupled to one another by a transmission mechanism. Basically, although double-shaft shredders using two drive motors are also known, these two drive motors cannot be controlled independently. The independent control of the drive motors allows, in addition to the selection of a particular operating mode, also a diagnosis of the double-shaft shredder. Thereby, the respective current consumption of the drive motors and thus the torque applied on the respective cutter block can be determined. If, for example, it is determined that one of the cutter blocks carries a significantly increased load over a particular period of time, this can indicate a malfunction of the double-shaft shredder. On the one hand, a foreign object can be stuck in the area of the cutter block, which thus takes up an increased load. On the other hand, there can also be a bearing damage on the respective cutter block. Both can be determined by an increased load of the respective drive motor.

[0037] If the two cutter blocks are driven in opposite directions at substantially the same rotational speed, a uniform shredding is achieved. In contrast, different rotational speeds result in a stronger relative movement between the cutter blocks, so that the cutter blocks can "freely mill" into one another. It is particularly advantageous here that, in the second operating mode, the first cutter block is first driven at a first rotational speed and the second cutter block is driven at a second rotational speed, wherein, over a predetermined first duration, the first rotational speed is higher than the second rotational speed, and then, over a predetermined second duration, the second rotational speed is higher than the first rotational speed. Thereby, the respective intermediate spaces between the knives of the cutter blocks can freely mill into one another. Furthermore, by this alternating rotational speed change of the cutter blocks, a more uniform load and thus a more uniform wear at the cutter blocks is achieved. Both result in an improved maintenance and an improved service life of the double-shaft shredder.

[0038] If a foreign object is to be jammed in the shredding space, the same direction of rotation of the cutter blocks is particularly useful. Thereby, for example, one of the maintenance flaps can be opened and the individual cutter blocks are driven in the same direction, so that the foreign object can be transported out of the double-shaft shredder through the opened maintenance flap. If the respective maintenance flap is provided as in the first aspect of the application and, for example, also a lifting device, for example a hydraulic system, for opening the respective maintenance flap is provided, this can also be done automatically and / or periodically. In this case, the electronic control unit also actuates the lifting device in order to cause the maintenance flap to be opened for a short time. The control unit can have or be connected with an activation key, by means of which the opening of the respective maintenance flap can also be released additionally. Such an activation key can increase the safety of the operator. After the foreign object has been thrown out, the maintenance flap can again be brought into the closed position, if possible by means of the electronic control unit.

[0039] The electronic control unit preferably has an internal memory and a processor, wherein a code is stored in the internal memory, which, when implemented by the processor, causes the electronic control unit to actuate the first and second drive motors as described.

[0040] In a preferred embodiment, the electronic control unit is provided for actuating the drive motors such that the individual cutter blocks have a small rotational speed difference relative to one another. A small rotational speed difference proves to be particularly suitable for releasing the intermediate spaces between the cutter blocks. It is also preferred here that one cutter block after the other is driven at a higher rotational speed. These predetermined durations are preferably about 30 seconds, 1 minute, 2 minutes, 10 minutes or 1 hour.

[0041] In a preferred embodiment, the electronic control unit is provided for actuating the drive motors such that only one of the individual cutter blocks rotates, while the other cutter block is stationary. This is particularly useful for transporting elements jammed in the intermediate spaces from the stationary cutter block. It can also be provided that the stationary cutter block rotates at a very low rotational speed, which is about 10% or 5% of the rotational speed of the faster rotating cutter block. Thereby, it is possible to gradually mill around the stationary or slowly rotating cutter block.

[0042] Here, the rotating cutter blocks are preferably rotated in the opposite direction to the shredding direction. Thereby, the jammed elements can then be transported in the direction of the entry opening and finally transported out of the double-shaft shredder through, for example, one of the opened maintenance flaps.

[0043] It has been shown that different control strategies can be used to solve the problems in the double-shaft shredder. For example, as a first problem-solving strategy, the ratio of the rotational speeds can be exchanged. That is, for example, if the first cutter block is rotated at a higher rotational speed than the second cutter block, this is reversed and the second cutter block is then rotated at a higher rotational speed than the first cutter block. A second problem-solving strategy consists in stopping one cutter block or reducing the rotational speed of the second cutter block to 5-10%. A third problem-solving strategy consists in changing the direction of rotation of the rotating cutter block in the second problem-solving strategy. A fourth problem-solving strategy consists in driving the cutter blocks in the same direction and here preferably opening one or both of the maintenance flaps in the maintenance flap. In a fifth problem-solving strategy, it can also be provided that the rotational speed is changed for a short time, for example in a pulsed manner, in a sinusoidal manner, or for a short time at maximum power. The electronic control unit can be designed to execute the above-mentioned problem-solving strategies according to this sequence in the event of a fault, in particular determined on the basis of the current consumption of the first and second drive motors. Each problem-solving strategy is preferably implemented for a predetermined duration. If it is determined that the fault is still present or has not been sufficiently resolved, the next problem-solving strategy is applied. It can be provided here that the electronic control unit is configured to learn. The learning can consist, inter alia, in that, when another fault occurs after the first fault has been eliminated, the electronic control unit then first applies the last successful problem-solving strategy and only thereafter applies the other problem-solving strategies. In this way, efficiency can be improved. It is preferably provided that a ranking of the problem-solving strategies is stored in the electronic control unit, which ranking is determined according to the frequency of its success. It is preferable that the problem-solving strategies are then applied individually according to this ranking.

[0044] In a preferred development, the respective transmission is configured as a bevel gear transmission. On the one hand, the bevel gear transmission is efficient, on the other hand, the bevel gear transmission enables a particularly space-saving arrangement of the drive motors. The bevel gear transmission is preferably configured as a cylindrical gear helical transmission, so that noise and surface pressure in the transmission can be reduced.

[0045] In a third aspect, the present application achieves the tasks mentioned at the outset by a method for maintaining a twin-shaft shredder, preferably a twin-shaft shredder according to one of the preferred embodiments of the twin-shaft shredder described above according to the first and / or second aspect of the present application. The method comprises the steps of: bringing a first maintenance flap from a closed position into a release position; and horizontally and laterally extracting a first cutterhead unit, the first cutterhead unit having a first cutterhead block with a plurality of first cutterheads arranged on a first hub such that there is an intermediate space between two adjacent first cutterheads, wherein the first cutterhead unit has a first bearing unit with a first bearing housing on a first axial end and a second bearing unit with a second bearing housing on a second axial end, the first cutterhead block being rotatably supported in the first and second bearing units about a first axis of rotation. The lateral extraction preferably relates here to the flow direction of the twin-shaft shredder from the inlet opening to the discharge opening. According to the method, the cutterhead unit is extracted horizontally from the side with respect to the inlet opening and the discharge opening. It is to be understood here that horizontal does not mean strictly geometric, but rather that an essentially horizontal extraction is sufficient.

[0046] The twin-shaft shredder according to the first aspect of the present application and the method according to the third aspect of the present application have similar and identical sub-aspects. In this respect, full reference is made to the above description of the first aspect of the present application. The advantages described with reference to the twin-shaft shredder according to the first aspect of the present application apply analogously or identically by means of the method. In particular, the first cutterhead unit can be extracted from the twin-shaft shredder without disassembling the inlet funnel or the like. According to the present application, this is done laterally and horizontally, which significantly simplifies the exchange. Preferably, the method further comprises the step of: horizontally and laterally extracting a second cutterhead unit, the second cutterhead unit having a second cutterhead block with a plurality of second cutterheads arranged on a second hub such that there is an intermediate space between two adjacent second cutterheads, wherein the second cutterhead unit has a third bearing unit with a third bearing housing on a first axial end and a fourth bearing unit with a fourth bearing housing on a second axial end, the second cutterhead block being rotatably supported in the third and fourth bearing units about a second axis of rotation. The first and second cutterhead units are preferably extracted from the twin-shaft shredder transversely to their respective axes of rotation.

[0047] Preferably, the individual steps are carried out without exposing the inlet opening and / or the discharge opening, in particular without disassembling the filling funnel at the inlet opening and / or the discharge tube at the discharge opening.

[0048] According to the embodiment it can be provided that the disengaging step of the counterpart holding piece is performed, more precisely before the taking-out step. Preferably, the disengaging step of the counterpart holding piece is performed after the step of bringing the first maintenance flap from the closed position into the release position. The disengaging step of the counterpart holding piece can comprise the disengaging of the first, second, third and fourth counterpart holding piece, in particular by disengaging the threaded connection between the first, second, third and / or fourth counterpart holding piece and the shredder housing of the double shaft shredder.

[0049] Preferably, the method further comprises the steps of horizontally and laterally embedding the cutterhead unit, preferably fixing the counterpart holding piece for form- and / or force-locking locking of the first cutterhead unit on the shredder housing, and bringing the first maintenance flap from the release position into the closed position.

[0050] Furthermore, in a fourth aspect, the present application comprises a method for operating a double shaft shredder, preferably a double shaft shredder according to one of the above described embodiments of the first and / or second aspect of the present application. The method for operating a double shaft shredder can also be understood as an extension of the method for maintaining a double shaft shredder and the steps described below can in particular be carried out after the maintenance of the double shaft shredder or before the maintenance of the double shaft shredder. In a first embodiment, the method for operating a double shaft shredder comprises the steps of driving both cutterhead blocks in a first operating mode over a first operating duration, terminating the first operating mode after the end of the first operating duration, and driving both cutterhead blocks in a second operating mode over a second operating duration.

[0051] Preferably, the first operating mode comprises driving both cutterhead blocks in opposite directions at substantially the same rotational speed, and the second operating mode comprises driving only one of the two cutterhead blocks while the other cutterhead block is stationary. Preferably, both cutterhead blocks are driven in opposite directions at substantially the same rotational speed over the first operating duration during normal operation of the double shaft shredder. In a cleaning operation, then preferably only one of the two cutterhead blocks is driven while the other cutterhead block is stationary. In this way, the intermediate spaces in the stationary cutterhead block can be "freely milled" by the rotating cutterhead block and components that are stuck there can be cleaned.

[0052] Additionally or alternatively, in the first operating mode, the cutterhead blocks are driven at substantially the same rotational speed, while in the second operating mode, the cutterhead blocks are driven at different rotational speeds. The cutterhead blocks can also be driven in opposite directions in the first operating mode and in the same direction in the second operating mode.

[0053] During the driving of both cutter blocks in opposite directions at substantially the same rotational speed, the rotation speed is preferably alternated. Substantially the same rotational speed also includes rotational speeds which slightly differ from each other. During normal operation, preferably one of the cutter blocks rotates at a higher rotational speed than the other cutter block. In this respect, the normal operation preferably comprises the following steps: driving the first cutter block at a first rotational speed and the second cutter block at a second rotational speed during a first section of a first duration of operation, wherein the first rotational speed is higher than the second rotational speed. During a second section of the first duration of operation following the first section, the first cutter block is driven at the first rotational speed and the second cutter block is driven at the second rotational speed, during which the second rotational speed is greater than the first rotational speed. This can be followed by a third, fourth and fifth section, wherein the third section is then preferably configured similarly to the first section, while the fourth section is configured similarly to the second section. This preferably also applies to further N+1 sections. The method also preferably comprises the following steps: bringing a lateral maintenance flap from a closed position into a release position; and driving both cutter blocks in the same direction towards the maintenance flap for ejecting foreign objects. Here, the cutter blocks preferably rotate more slowly than during normal operation, preferably at a speed of approximately 10% or less of the maximum rotational speed. It can occur that elements which cannot be shredded by the cutter blocks can enter the shredding space through the entry opening. This can involve, for example, larger metal blocks, stones, etc. Such foreign objects must then be ejected. On the one hand, this can be done manually in such a way that an employee reaches into the entry opening via the entry funnel and - with the cutter blocks at a standstill - manually removes the foreign objects. According to the solution presented here, however, the lateral maintenance flap, either the first maintenance flap or the second maintenance flap, is brought from the closed position into the release position and the cutter blocks are rotated towards the maintenance flap. That is to say, the orientation of the cutter blocks with respect to the double-shaft shredder is such that the upper cutting teeth are moved towards the maintenance flap. Thus, if the maintenance flap is located in the 3 o'clock direction with respect to the rotational axis of the cutter unit, the cutter blocks should be rotated in a clockwise direction. If the maintenance flap is located in the 9 o'clock direction, the cutter blocks are rotated in an anticlockwise direction. The foreign objects are usually resting at the upper part of the cutter blocks, as they cannot be shredded. By driving the cutter blocks in the same direction towards the maintenance flap, the foreign objects can thus be transported out of the shredding space. These steps can also be carried out instead of the following step: driving only one of the two cutter blocks during a second duration of operation, while the other cutter block is at a standstill. The first or second maintenance flap can be opened by means of a control unit or be connected to such a control unit. The control unit can have an activation key or be connected to such an activation key. The method can comprise the following step: bringing the first maintenance flap from the closed position into the release position by releasing the activation key.

[0054] Preferably, the method further comprises closing the maintenance flaps after the foreign object has been expelled and driving the first and second cutter block under normal operation. Normal operation preferably comprises driving the cutter blocks in opposite directions at substantially the same rotational speed.

[0055] Further preferably, the method comprises the steps of detecting a first load uptake of the first drive motor of the first cutter block, detecting a second load uptake of the second drive motor of the second cutter block, and determining a malfunction of the dual-shaft shredder based on the detected first and second load uptake. In case of electric motors as drive motors, for example the current consumption can be measured. Alternatively, also the torque, the stress in the shaft, the force in the coupling, the noise, etc. can be detected.

[0056] Embodiments of the application will now be described, by way of example, with reference to the accompanying drawings. These embodiments are not necessarily to scale, as the emphasis is on illustrating the principles of the application. In the drawings, like reference numerals are used to refer to like parts throughout the various views. The embodiments are not intended to limit the scope of the application, but rather, the scope of the application is to be accorded the full breadth of equivalent sides and / or scope of the appended claims. To the accomplishment of the foregoing and related ends, the application, then, comprises the features hereinafter fully described and particularly pointed out in the claims. The following description and the annexed drawings are included to provide a thorough understanding of the application. They comprise various objects and aspects of and that can be made by the application. They comprise preferred examples of components and / or configurations of the application. Other objects, aspects, examples and / or configurations of the application will occur to those skilled in the art upon consideration of this disclosure, and are encompassed within the spirit of the application as defined by the scope of the claims. BRIEF DESCRIPTION OF DRAWINGS

[0057] Further advantages, features and details of the application result from the following description of preferred embodiments and by means of the drawings; in which:

[0058] Figure 1 a perspective view of a dual-shaft shredder is shown, wherein the first and second maintenance flaps are closed;

[0059] Figure 2 a perspective view of a dual-shaft shredder is shown, Figure 1 in which the first and second maintenance flaps are open;

[0060] Figure 3a a detail is shown, Figure 1 in the dual-shaft shredder of

[0061] Figure 3b a detail is shown, Figure 2 in the dual-shaft shredder of

[0062] Figure 4 schematic view showing the lateral extraction of the first and second cutterhead units;

[0063] Figure 5 schematic view showing the parallel kinematic mechanism for bringing the first maintenance flap from the closed position into the release position;

[0064] Figure 6 perspective view showing Figure 1 a double shaft shredder in which the maintenance flap is open and the cutterhead units are in the extracted state;

[0065] Figure 7 perspective view showing the cutterhead units together with the first and second counter-holders;

[0066] Figure 8 cross-sectional view showing the cutterhead units;

[0067] Figure 9 perspective view showing Figure 1 further details;

[0068] Figure 10 perspective exploded view showing the coupling device.

[0069] Figure 11 cross-sectional view showing Figure 10 the assembled coupling device in the double shaft shredder;

[0070] Figure 12 torque support of the drive motor;

[0071] Figure 13 schematic view showing the drive control of the double shaft shredder; and

[0072] Figure 14 another schematic view showing the drive control of the double shaft shredder. DETAILED DESCRIPTION

[0073] A double shaft shredder 1 for shredding solids or solids in a liquid has a shredder housing 2 which defines a shredding space 4 inside. The shredder housing 2 is here arranged on a frame 6 which carries the shredder housing 2. At the upper side of the shredder housing 2 with reference Figure 1 to the inside, an entry opening 8 is configured which is here provided with a filling hopper 10. The filling hopper 10 itself has a grid 11 to prevent too large objects from passing through the filling hopper 10 into the entry opening 8. The grid 11 is optional and can also be omitted, for example, if larger objects are to be filled into the filling hopper 10. An exit opening 12 of the double shaft shredder 1 is configured with reference Figure 1arranged at the lower side and not further visible here. The discharge opening 12 is arranged opposite the entry opening 8, so that fluid can pass through the double shaft shredder 1 from top to bottom vertically. In the installed state, the discharge opening 12 can be connected with a pipe or the like to lead off the shredded material. Figure 1 From top to bottom, vertically through the double shaft shredder 1. In the installed state, the discharge opening 12 can be connected with a pipe or the like to lead off the shredded material.

[0074] In operation, the first and second cutter block units 14, 16 rotate inside the shredding space 4, which is described in more detail below with reference to Figure 4 , 6 , 7 and 8. The first cutter block unit 14 has a first rotation axis Al, while the second cutter block unit 16 has a second rotation axis A2. The rotation axes Al, A2 are parallel to each other, but offset. In this way, the individual knives of each cutter block unit 14, 16 can mesh with each other in order to thereby cut open the material. This is basically known.

[0075] In order to drive the first cutter block unit 14, a first drive motor 18 is provided, and in order to drive the second cutter block unit 16, a second drive motor 20 is provided. Both are controlled by a common electronic control unit 22, which is also fixed here on the 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 transmission 19 and connected with the first cutter block unit 14 by means of the transmission. The second drive motor 20 is equipped with a second transmission 21 and connected with the second cutter block unit 16 by means of the transmission. In this way, the installation of the first and second drive motors 18, 20 is simplified. The first and second transmissions 19, 21 are preferably configured as bevel gear transmissions, but are not shown in detail here.

[0076] As can be derived from Figure 1 It is also derived that the shredder housing 2 has an entry side 24, on which the filling hopper 10 is received and in which the entry opening 8 is configured. In Figure 1 In the embodiment shown, the entry side 24 is oriented essentially upwards. Furthermore, the shredder housing 2 has a discharge side 26, which has the discharge opening 12, which is here the lower side of the shredder housing 2. The first and second drive motors 18, 20 are arranged on a first and a second end side 28, 30. The first and second end sides 28, 30 are arranged essentially perpendicular to the first and second rotation axes Al, A2 and connect the entry side 24 and the discharge side 26 to each other. Furthermore, a first lateral side 32 and a second lateral side 34 are configured on the shredder housing 2.

[0077] A problem in conventional double shaft shredders is the maintenance of the first cutter block unit 14 and the second cutter block unit 16. For example, the first cutter block unit 14 has a first cutter block 40, while the second cutter block unit 16 has a second cutter block 42 (see Figure 4 and7 ). Each of the cutter blocks 40, 42 is equipped with a plurality of cutters, i.e. the first cutter block 40 is equipped with first cutters 44 (only one of which is provided with reference numerals in Figure 7 and Figure 8 and the second cutter block 42 is equipped with second cutters 46. The first and second cutters 44, 46 are axially spaced apart from each other, respectively, so that the cutters 44, 46 of the first and second cutter blocks 40, 42 can engage each other, as this is basically known in the prior art, in particular with reference to DE 202010010662 U1 and WO 2018087398. The cutters 44, 46 of the first and second cutter blocks 40, 42 can wear over time, so that they have to be maintained or replaced. To simplify this, the present application implements a horizontal maintenance concept, which is described below.

[0078] To implement the horizontal maintenance, the double-shaft shredder 1, more precisely the shredder housing 2, has a first maintenance flap 50, which is preferably constructed on the first lateral side 32 of the shredder housing 2. The first cutter unit 14 can be extracted from the shredder housing 2 via the first maintenance flap 50. It can be provided that the second cutter unit 16 can also be extracted from the shredder housing 2 via the first maintenance flap 50. According to the embodiment shown here, however, the shredder housing 2 has a second maintenance flap 52, which is assigned to the second cutter unit 16. The first and second maintenance flaps 50, 52 are described below in total, wherein it is to be understood that embodiments can also exist which have only one of the maintenance flaps 50, 52, which then provides access to both cutter units 14, 16.

[0079] Figure 1 The first maintenance flap 50 is shown in the closed position P11. The second maintenance flap 52 is also in the closed position P12. In contrast thereto, in Figure 2 , the first maintenance flap 50 is in the release position P21 and the second maintenance flap 52 is also in the release position P22. In the release positions P21, P22, the first and second maintenance flaps 50, 52 are pivoted upwards, while preferably not rotating about their own axis here. In order to enable the pivoting of the first and second maintenance flaps 50, 52, the double-shaft shredder 1 has a first parallel movement mechanism 54 for the first maintenance flap 50 and a second parallel movement mechanism 56 for the second maintenance flap 52. The first and second parallel movement mechanisms 54, 56 are basically identically constructed, so that only the first parallel movement mechanism 54 is described below. It is to be understood that the second parallel movement mechanism 56 can be constructed analogously to the first parallel movement mechanism 54. The first and second parallel movement mechanisms 54, 56 can be arranged on the first lateral side 32 of the shredder housing 2, in particular on the first maintenance flap 50, 52, respectively. Figure 3a and 3bThis is particularly clear from the figures below, which are referred to in the following. Furthermore, the parallel kinematic mechanisms 54, 56 are again shown in Figure 4 and 5 . The first parallel kinematic mechanism 54 has a first parallelogram lever 58 and a second parallelogram lever 60. The first parallelogram lever 58 is connected with the shredder housing 2 at a first articulation point 59a and with the first maintenance flap 50 at a second articulation point 59b. The second parallelogram lever 60 is connected with the shredder housing 2 at a first articulation point 61a and with the maintenance flap 50 at a second articulation point 61b. The first articulation points 59a, 61a of the first and second parallelogram levers 58, 60 are oriented substantially vertically above one another and substantially above the maintenance flap 50. In the closed position P11, P12, the first and second parallelogram levers 58, 60 are pivoted downwardly, so that the first maintenance flap 50 is oriented substantially below the first and second articulation points 59a, 61a. The parallel kinematic mechanism 54 is connected with a first lifting device 62, which here comprises a first pneumatic cylinder 63. In the embodiment shown, the pneumatic cylinder 63 acts on the first parallelogram lever 58 in order to pivot this first parallelogram lever about the first articulation point 59a. Thereby, the first maintenance flap 50 is lifted out of the closed position P11 and moved upwardly, so that the first maintenance flap reaches the release position P21 shown in Figures Figure 2 , 3b and 4.

[0080] The first and second parallel kinematic mechanisms 54, 56 are described only with reference to the first end side 34 of the shredder housing 2. On the second end side 30, too, a corresponding parallel kinematic mechanism is arranged, so that the first and second maintenance flaps 50, 52 can be lifted and lowered by two such parallel kinematic mechanisms.

[0081] As emerges in particular from Figure 4 , first and second scrapers 66, 68 are arranged on the first and second maintenance flaps 50, 52, which are used to prevent, on the one hand, unshredded material from passing between the maintenance flaps 50, 52 and the respective knife disc block 14, 16 in operation, and, on the other hand, also to keep the intermediate space between the first and second knife discs 40, 44 free. The first and second scrapers 66, 68 are arranged here on the first and second maintenance flaps 50, 52, so that the first and second scrapers move together with the first and second maintenance flaps 50, 52 from the closed position into the release position. In this way, the first and second knife disc units 14, 16 are particularly easily and extensively released.

[0082] After the first and second maintenance flaps 50, 52 have been brought into the release positions P21, P22, the first and second knife disc units 14, 16 can be essentially removed from the shredder housing 2, more precisely along the first and second removal directions E1, E2 (see Figure 2 ). In Figure 2 and 3b , the first and second knife disc units 14, 16 have been removed. The removal of the first and second knife disc units 14, 16 can be seen schematically in Figure 4 and will now be described in more detail with reference to Figure 4 , 6 , 7, 8 and 9.

[0083] The first knife disc unit 14 is shown separately and in perspective view in Figure 7 . The cross section of this first knife disc unit 14 is shown in Figure 8 . Figure 8 The cross section in Figure 8 extends horizontally and Figure 7 is a top view. Even if only the first knife disc unit 14 is shown in Figure 8 , it is to be understood that the second knife disc unit 16 is identically configured and that the following description applies to the second knife disc unit 16 as well.

[0084] In the shown embodiment, the first knife disc 44 is arranged on the first hub 70 and integrally configured therewith. The knife disc block 40 is thus configured as a so-called monolithic knife disc block. However, this is not mandatorily required and also comprises embodiments in which the first knife disc 40 is connected to the first hub 70 in a force- and / or form-locking manner. Figure 8 In , optional first and second slots 300 configured on the hub 70 are also shown. Each slot 300 is indicated by a dashed line, whereby it is indicated that said slot is optional.

[0085] Figure 8 The first hub 70 extends on the left-hand side into a first shaft end 72, which can be coupled with the first transmission 19. On the right-hand side with reference to Figure 8 , the knife disc block 40 has a second shaft end 76. The left-hand end of the knife disc block 40, on which the first shaft end 72 is arranged, is received in a first bearing unit 80, and the second shaft end 76 is received in a second bearing unit 82. The second knife disc unit 16 is also configured correspondingly and has a third bearing unit 84 and a fourth bearing unit 86 (see Figure 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 block 40, 42 are rotatably supported in the first, second, third and fourth bearing housing 81, 83, 85, 87. By means of the first, second, third and fourth bearing housing 81, 83, 85, 87, the first or second cutter unit 14, 16 is fixed to the shredder housing 2. Reference is made to Figure 8 It can be seen that in the first bearing housing 81 a first bearing 90 in the form of a double-inclined roller bearing is arranged in an X arrangement. Between the bearing housing 81, which carries the outer ring of the first bearing 90, and the first bushing 91, a first seal 92 is arranged. The first seal 92 is configured here as a contact seal and serves to seal the cutter block 44 with respect to the bearing housing 81. The inner ring of the first bearing 90 is pressed onto the first shaft end 72 and is fixed there in a force-locking manner. Furthermore, a nut 93 is arranged, which supports the inner ring. The bearing housing 81 is then closed with a first bearing cover 94. The first bearing cover 94 is screwed with respect to the first bearing housing 81 by means of a screw connection (see Figure 9 ). In the first bearing cover 94, a first lubrication nipple 95 is also arranged in order to be able to lubricate the first bearing 90.

[0087] The second bearing unit 82 has a second bearing 96, which is formed here as a rolling bearing and a floating bearing. The bearing outer ring is in turn received in the second bearing housing 83, and the inner ring is pressed onto the second shaft end 76. As already mentioned above, the second shaft end 76 is detachably connected with the hub 70. Between the bearing housing 83 and the second bushing 97, which is arranged frictionally locked on the second shaft end 76, a contact second seal 98 is arranged, which in turn seals the cutter block 40 with respect to the bearing housing 82 and thereby prevents liquid from reaching the second bearing 96. The second bearing housing 82 is closed by means of a second bearing cover 99, which in turn is fixed on the second bearing housing 82 by means of a screw connection. The second bearing unit 82 is formed analogously to the third bearing unit 85, so that the shape of the second bearing cover 99 corresponds to the shape of the third bearing cover 100, which can be seen in Figure 9 . The third bearing cover 100 is provided with a third lubrication nipple 102 in order to lubricate the bearing received therein. Analogous lubrication nipples are also provided for the second bearing 96 and the fourth bearing (not shown).

[0088] A particular advantage of the present application is that the cutterhead units 14, 16 can be removed from the shredder housing 2 together with the first, second, third and fourth bearing units 80, 82, 84, 86. That is to say, the bearings themselves do not have to be dismantled within the shredder housing, so that the bearings are significantly less prone to damage and can also be more easily maintained. To this end, the first and second bearing housings 81, 83 have first and second mounting surfaces 104, 106 which, on the one hand, can abut against first and second mounting recesses 108, 110 (see Figure 4 ) of the shredder housing 2 and, on the other hand, interact with first and second counter-holdings 110, 112 in order to fix the first cutterhead unit 14 on the shredder housing 2. The first and second counter-holdings 110, 112 are also shown in cross-section in Figure 8 , since the cross-section according to Figure 8 is a view from above. In order to achieve a further sealing here, first and second O-rings 105, 107 are also arranged in the first and second mounting surfaces 104, 106 which, on the one hand, can abut against the first and second counter-holdings 110, 112 and, on the other hand, can abut against the first and second mounting recesses 108, 110 in order to seal the first and second bearing housings 81, 83 with respect to the shredder housing 2.

[0089] The third and fourth bearing housings 84, 86 are configured in the same way and can be inserted into third and fourth mounting recesses 114, 116 (see Figure 4 ) and fixed there by means of respective third and fourth counter-holdings 118, 120. The first, second, third and fourth counter-holdings 110, 112, 118, 120 have counter-holding surfaces 122, 124 which correspond to the first and second mounting surfaces 104, 106 of the first and second bearing housings 81, 83. Likewise, the third and fourth counter-holdings 118, 120 have such surfaces. Furthermore, the first and second counter-holdings 110, 112 each have mounting holes 126 into which counter-holding screws 128 can be engaged in order to fix the first and second counter-holdings 110, 112 with respect to the shredder housing 2. Such mounting holes 126 and counter-holding screws 128 are also provided for the third and fourth counter-holdings 118, 120 (see Figure 9When the first maintenance cover is in the closed position P11, the mating retainer threaded part 128, and therefore the first and second mating retainers 110, 112, are covered by the first maintenance cover 150. Similarly, when the second maintenance cover is in the closed position P12, the mating retainer threaded part 128 of the third and fourth mating retainers 118, 120 is covered by the second maintenance cover 52. This prevents the mating retainers from being released, even when the first and second maintenance covers 50, 52 are in the closed position.

[0090] Therefore, in order to remove the first and second cutter disc units 14, 16 from the shredder housing 2, the first and second maintenance covers 50, 52, 10 must first be brought to the release positions P21, P22. Then, the first and second mating retainers 110, 112 or the third and fourth mating retainers 118, 120 must be disengaged. Previously, as... Figure 6 As shown, maintenance bracket 130 is preferably fixed on frame 6 to prevent the corresponding cutter head unit ( Figure 6 The second cutter head unit 16 falls off after the third and fourth mating retainers 118 and 120 disengage. A maintenance bracket 130 is supported on the frame 6 and, in this embodiment, has first, second, and third carriers 131, 132, and 133, wherein an optional gripper 134 is provided on the second carrier 132. In other embodiments, only two carriers or four or more carriers may be provided. The gripper 134 has claws 135 capable of gripping the cutter head unit 16 circumferentially. A pull rod 136 with handles 137a and 137b is provided on the claws 135, by means of which the claws 135 can be guided to the cutter head unit 16. The cutter head unit 16 should be gripped by the claws 135 as long as it remains within the shredder housing 2. The cutter head unit can then be pulled out of the shredder housing 2 via pull rods 136 and 25, the cutter head unit resting against the first, second, and third supports 131, 132, and 133. The cutter head block 40 may be provided with a first groove 300, such as... Figure 8The slots 300, 30 enable the knife disc unit 16 to be axially positioned above the carriers 131, 132, 133. The knife disc unit 16 can be rolled out of the shredder housing 2 along the carriers 131, 132, 133, for example manually, wherein the knife disc unit 16 rests on the first, second and / or third carriers 131, 132, 133 and is guided via the slots 300, so that the axial positioning of the knife disc unit 16 is maintained even during the rolling out. This has the advantage that the position of the bearing housings 81, 83 in the axial direction relative to the rotation axis is maintained or fixed by the slots 300. The knife disc unit 16 can then be transported away from here, for example by means of a crane. The first and second knife disc units 14, 16 are preferably reinserted into the shredder housing 2 in a similar manner. Thereby, on the one hand, simple and reliable maintenance can be achieved, and on the other hand, the risk of injury can be minimized.

[0091] The first and second knife disc blocks 40, 42 of the first and second knife disc units 14, 16 are connected with the first and second drive motors 18, 20 via first and second coupling devices 200, 202, as Figure 10 and 11 is shown. Only one of these coupling devices 200, 202 will be described below, namely the first coupling device 200 exemplarily. The same embodiments preferably apply to the second coupling device 202, but the second coupling device can also be configured differently or similarly.

[0092] In the shown embodiment, the first and second knife disc blocks 40, 42 are connected with the first and second drive motors 18, 20 via first and second transmission mechanisms 19, 21, i.e. the transmission mechanisms are not mandatorily required, and the first and second drive motors 18, 20 can be coupled directly.

[0093] The first transmission mechanism 19 has a first driven shaft 204, which is equipped at its distal end with a first coupling disc 206. The first coupling disc 206 has a first conical section 208 (see Figure 11), which is configured here as a male taper. The second coupling disc 210 is mounted on the shaft end 72 in a rotationally fixed manner. Both the first coupling disc 206 and the second coupling disc 210 are provided with a plurality of through-holes, so that the first and second coupling discs can be tensioned relative to one another by means of coupling screws 212. In order now to center the first coupling disc 206 relative to the second coupling disc 210 and thus the driven shaft 204 relative to the shaft end 72, a centering pot 214 is provided. The centering pot 214 also has a through-hole, so that the centering pot can be tensioned relative to the first and second coupling discs 206, 210, preferably by means of the coupling screws 212. The centering pot 214 is mounted with its flange 216 on a radial centering face 218 of the second coupling disc 210 and with its bottom 220 behind the first coupling disc 206. On the centering pot 214, between the flange 216 and the bottom 220, a second taper 222 is configured, which corresponds to the first taper 208 and can act together with the first taper for centering. Thus, when the coupling screws 212 are tightened, the second taper 222 is pressed against the first taper 208 and thus the first coupling disc 206 is centered on the centering pot 214.

[0094] In order to additionally center the second coupling disc 210 on the shaft end 72, in this embodiment a first taper ring 224 is provided, which extends with a first tapering protrusion 226 between the first coupling disc 210 and the shaft end 72, and a second taper ring 228 is provided, which extends with a second tapering protrusion 230 between the first coupling disc 210 and the shaft end 72 and which is arranged opposite the first taper ring 224. The two taper rings 224, 228 are tensioned relative to one another by means of a ring screw 232. In this way, the second coupling disc 210 is centered on the shaft end 72. Furthermore, the driven shaft 204 is also oriented in alignment with the shaft end 72. Both angular errors and radial offsets are thus compensated.

[0095] Figure 10 and Figure 12 A drive support for the drive motor is now shown. The first drive motor 18 is supported on the frame 6 by means of a first drive support 240 (see Figure 1 ) while the second drive motor 20 is supported on the frame 6 by means of a second drive support 242. In the following, only the first drive support 240 is explained, wherein the same explanations preferably also apply to the second drive support 242.

[0096] The first drive bearing 240 comprises a first torque support 244 and a second torque support 246. The first drive bearing 240 is configured as a floating bearing and does not center the first drive motor 18 and the first transmission 19 with respect to the first cutter block 40; this is achieved by the first coupling device 200 as described above. In operation, the first and second torque supports 244, 246 are preferably only used for supporting torque. The first and second torque supports can also be configured such that they partially absorb the weight force in order to partially reduce the load of the bearings of the cutter block. When the first and second coupling devices 252, 202 are open, the first and second torque supports 244, 246 receive the weight force of the first and second drive motors 18, 20, if possible also together with the weight force of the first and second transmissions 19, 21. That is, the first and second torque supports are then slightly sagging.

[0097] The first torque support 244 here comprises a first damper assembly 250 in order to support the torque in the first direction of rotation and a second damper assembly 252 in order to support the torque in the second, opposite direction of rotation. The second torque support 246 also comprises a first and a second damper assembly (not shown, see Figure 10 ). Each damper assembly 250, 252 also comprises two rubbers which are fixed on a crossbar 254. The crossbar 254 itself is fixed on a first transmission housing 260 via a first and a second support plate 256, 258, which first transmission housing itself also carries the first drive motor 18.

[0098] The first and second drive motors 18, 20 can be controlled independently by the electronic control unit 22. This enables the dual-shaft shredder 1 to be operated in two or more operating modes. For example, in a first operating mode, the first and second cutter blocks 40, 42 are so manipulated that they are rotated in the same direction at substantially the same rotational speed. In a second operating mode, the drive motors 18, 20 are so manipulated by the control unit 22 that the first and second cutter blocks 40, 42 are driven at different rotational speeds and / or in the same direction of rotation. Figure 13This scenario is illustrated. Time is plotted on the horizontal axis, and rotational speed n is plotted on the vertical axis. At time point t0, the first cutter block 40 is driven at a rotational speed n1, which is higher than rotational speed n2, and the second cutter block 42 is driven at the same rotational speed n2. At time point t1, the electronic control unit 22 initiates a control switch and accelerates the second cutter block 42 until it reaches the first rotational speed n1 at time point t2. Simultaneously, the first cutter block 40 decelerates at time point t1 until it reaches a lower rotational speed n2 at time point t2. After a predetermined duration between the second time point t2 and the third time point t3, the dual-shaft shredder 1 continues operation. At time point t3, the first cutter block 40 accelerates again, from rotational speed n2 to speed n1, reaching that speed n1 at time point t4. Simultaneously, the second cutter block 42 is braked so that it reaches the second rotational speed n2 again at time point t4. Further such periods may follow. This operating mode has the following advantages: there is relative movement between the first and second cutter head blocks 40, 42, so that the first and second cutter head blocks can "freely mill" each other, that is, remove the components that may be attached to the intermediate space between the cutter heads.

[0099] Figure 14 This illustrates an alternative operating mode in which foreign object 200 is removed from the tearing space 4. If the foreign object 200 cannot be torn apart, it is removed despite the presence of the grille 11 (see...). Figure 1 The foreign object also enters the shredding space 4, and cannot reach the discharge opening 12 because it cannot be shredded and is restrained on the other side by scrapers 66 and 68. To automatically remove these foreign objects from the shredding space, it is preferable to open one of the maintenance covers 50 and 52. Figure 11 Open the second maintenance cover 52. Then rotate the two cutter disc blocks 40, 42 toward the opened maintenance cover, i.e., in a clockwise direction. In this way, the foreign object 200 moves through the cutter disc blocks 40, 42 toward the opened maintenance cover 52 and thus falls out of the shredder housing 2.

[0100] In this operating mode, it is important to implement appropriate safety measures for operators to prevent injury from the exposed cutterhead blocks on the sides. For example, it could be stipulated that this operation can only be carried out in enclosed spaces.

[0101] Other such operating modes are conceivable and preferred, and have already been described above. Preferably, such operating modes are stored in the electronic control unit 1022, and more preferably in a memory located therein. The electronic control unit 22 preferably has an operation panel 202 (see...). Figure 1 The operator can operate the dual-shaft shredder 1 through this control panel.

Claims

1. A dual-shaft shredder (1), the dual-shaft shredder being used to shred solids in a solid or liquid, the dual-shaft shredder comprising: - Shredder housing (2), the shredder housing defining the shredding space (4) inside. - An inlet opening (8) in the shredder housing (2) for supplying solids into the shredding space (4); - A discharge opening (12) in the shredder housing (2) substantially opposite to the inlet opening (8), the discharge opening being used to draw out shredded solids from the shredding space (4); - First cutter head unit (14), the first cutter head unit has a first cutter head block (40) with a plurality of first cutter heads (44), the first cutter heads are arranged on a first hub body (70) such that there is an intermediate space between two adjacent first cutter heads (44); - Second cutter head unit (16), the second cutter head unit has a second cutter head block (42) with a plurality of second cutter heads (46), the second cutter heads are arranged on the second hub body such that there is an intermediate space between two adjacent second cutter heads (46); -In this configuration, the first cutter head block (40) and the second cutter head block (42) are axially offset from each other with their rotation axes (A1, A2), such that at least some of the first cutter heads (44) are respectively engaged in the intermediate space between two adjacent second cutter heads (46) and some of the second cutter heads (46) are respectively engaged in the intermediate space between two adjacent first cutter heads (44). Its features are, - The first cutter head unit (14) has a first bearing unit (80) with a first bearing housing (81) at a first axial end and a second bearing unit (82) with a second bearing housing (83) at a second axial end. The first cutter head block (40) is rotatably supported in the first bearing unit and the second bearing unit about a first rotation axis (A1). - The second cutter head unit (16) has a third bearing unit (84) with a third bearing housing (85) at its first axial end and a fourth bearing unit (86) with a fourth bearing housing (87) at its second axial end. The second cutter head block (42) is rotatably supported in the third and fourth bearing units about the second rotation axis (A2). - The shredder housing (2) has a first maintenance flap (50) which is capable of occupying a release position (P21) and a closed position (P11) and allows the first cutter head unit (14) to be removed together with the first bearing unit (80) and the second bearing unit (82) in the release position (P21).

2. The dual-shaft shredder according to claim 1, wherein, The shredder housing (2) has a second maintenance flap (52) which can occupy a release position and a closed position and allows only the second cutter head unit (16) along with the third bearing unit (84) and the fourth bearing unit (86) to be removed in the release position.

3. The dual-shaft shredder according to claim 1 or 2, wherein, Each bearing unit includes a seal so that the bearings (90, 96) of each bearing unit are sealed relative to the cutter head block.

4. The dual-shaft shredder according to claim 1 or 2, wherein, The corresponding bearing housing of each bearing unit can be fixed to the shredder housing (2) in an anti-rotation manner when installed.

5. The dual-shaft shredder according to claim 1 or 2, wherein, The shredder housing (2) includes: an inlet side (24) having the inlet opening (8), an outlet side (26) having the outlet opening (12), a first end side (28) and a second end side (39) arranged perpendicular to the first rotation axis (A1) and the second rotation axis (A2), and a first transverse side (32) and a second transverse side (34), wherein the first maintenance cover (50) is arranged on the first transverse side (32).

6. The dual-shaft shredder according to claim 1 or 2, wherein, The first cutter head unit (14) can be removed from the shredder housing (2) along a first removal direction (E1), which is transverse to the first rotation axis (A1) and parallel to the plane defined by the first rotation axis (A1) and the second rotation axis (A2).

7. The dual-shaft shredder according to claim 1 or 2, wherein, The first cutter disc unit (14) is fixed to the shredder housing (2) by means of first and second mating retainers (110, 112).

8. The dual-shaft shredder according to claim 7, wherein, When the first maintenance cover (50) is in the closed position (P11), the first and second mating retainers (110, 112) are covered by the first maintenance cover (50), and when the first maintenance cover (50) is in the released position (P21), the first and second mating retainers are accessible.

9. The dual-shaft shredder according to claim 1 or 2, wherein, The dual-shaft shredder has a first parallel motion mechanism (54) for moving the first maintenance cover from the closed position (P11) to the released position (P21).

10. The dual-shaft shredder according to claim 9, wherein, The dual-shaft shredder has a first lifting device (62) that acts on a first parallel motion mechanism (54) to move a first maintenance cover (50) from a closed position (P11) to a released position (P21).

11. The dual-shaft shredder according to claim 1 or 2, wherein, The first cutter head block (40) and the second cutter head block (42) are provided with at least one first groove (300), and the carrier (131, 132, 133) can be engaged in the first groove for guidance.

12. The dual-shaft shredder according to claim 1, wherein, The dual-shaft shredder also includes: - First drive motor (18), which can drive first cutter block (40). - A second drive motor (20), which is capable of driving a second cutter head block (42); and - Electronic control unit (22) for controlling the first drive motor (18) and the second drive motor (20).

13. The dual-shaft shredder according to claim 12, wherein, The dual-shaft shredder also includes: -The first coupling device (200) between the first cutter head block (40) and the first drive motor (18), and - A second coupling device (202) between the second cutter head block (42) and the second drive motor (20). The first coupling device (200) has a first centering device for centering the first drive motor (18) relative to the first cutter head block (40), and the second coupling device (202) has a second centering device for centering the second drive motor (20) relative to the second cutter head block (42).

14. The dual-shaft shredder according to claim 13, wherein, The first centering device and the second centering device each have corresponding conical sections, and each conical section is clamped together with the other.

15. The twin-shaft shredder according to any one of claims 12 to 14, wherein, The first drive motor (18) and the second drive motor (20) are supported in a floating manner.

16. The dual-shaft shredder according to any one of claims 12 to 14, -in, The electronic control unit (22) is configured to operate the first drive motor (18) and the second drive motor (20) at least in the first operating mode and in the second operating mode different from the first operating mode.

17. The dual-shaft shredder according to claim 16, wherein, The electronic control unit (22) is configured to operate the first drive motor (18) and the second drive motor (20) in a first operating mode, such that the first cutter head block (40) and the second cutter head block (42) are driven in opposite directions at substantially the same rotational speed (n1, n2), and The electronic control unit (22) is configured to operate the first drive motor (18) and the second drive motor (20) in the second operating mode, such that the first cutter head block (40) and the second cutter head block (42) are driven at different speeds (n1, n2) and / or in the same direction of rotation.

18. The dual-shaft shredder according to any one of claims 12 to 14, wherein, The electronic control unit (22) is configured to control each drive motor so that each cutter block has a small speed difference relative to each other.

19. The dual-shaft shredder according to any one of claims 12 to 14, wherein, The electronic control unit (22) is configured to control each drive motor so that each cutter block has an alternating rotational speed.

20. The dual-shaft shredder according to any one of claims 12 to 14, wherein, The electronic control unit (22) is configured to control each drive motor so that only one cutter block rotates while the other cutter block remains stationary.

21. The dual-shaft shredder according to claim 20, wherein, The rotating blade block rotates in the opposite direction to the shredding direction.

22. The dual-shaft shredder according to claim 12, wherein, The first drive motor can drive the first cutter head block (40) through the first transmission mechanism (19); the second drive motor can drive the second cutter head block (42) through the second transmission mechanism (21).

23. The dual-shaft shredder according to claim 22, wherein, The first transmission mechanism (19) and the second transmission mechanism (21) are constructed as bevel gear transmission mechanisms.

24. A method for maintaining a twin-shaft shredder, said twin-shaft shredder being a twin-shaft shredder (1) according to any one of claims 1 to 23, said method comprising the following steps: - Bring the first maintenance cover (50) from the closed position (P11) to the released position (P21); - The first cutter head unit (14) is removed horizontally and laterally. The first cutter head unit has a first cutter head block (40) with a plurality of first cutter heads (44). The first cutter heads are arranged on the first hub (70) such that there is an intermediate space between two adjacent first cutter heads (44). The first cutter head unit (14) has a first bearing unit (80) with a first bearing housing (81) at a first axial end and a second bearing unit (82) with a second bearing housing (83) at a second axial end. The first cutter head block (40) is rotatably supported in the first bearing unit and the second bearing unit about a first rotation axis (A1).

25. The method according to claim 24, wherein, Each step is performed without exposing the inlet opening (8) and / or outlet opening (12).

26. The method of claim 25, wherein, Each step is performed without disassembling the filling funnel (10) at the inlet opening (8) and / or the discharge pipe at the outlet opening (12).

27. The method according to any one of claims 24 to 26, wherein, The method includes the following steps: - Disconnect the mating retainer before the removal step.

28. A method for operating a dual-shaft shredder, said dual-shaft shredder being a dual-shaft shredder (1) according to any one of claims 12 to 23, said method comprising the following steps: - Drive two cutterhead blocks during the first operating duration in the first operating mode; - Terminate the first running mode after the first running duration ends; and - Drive both cutterhead blocks during the second operating duration in the second operating mode.

29. The method according to claim 28, wherein, In the first operating mode, the two cutter blocks are driven at essentially the same speed, while in the second operating mode, they are driven at different speeds.

30. The method according to claim 28, wherein, In the first operating mode, the two cutter blocks are driven in opposite directions, while in the second operating mode, only one of the two cutter blocks is driven.

31. The method according to any one of claims 28 to 30, wherein, The method includes the following steps: - Bring one of the maintenance flip covers from the closed position to the released position; - Drive the two cutterhead blocks in the same direction toward the maintenance flip cover to eject foreign objects.

32. The method according to any one of claims 28 to 30, wherein, The method includes the following steps: - The first maintenance flip cover (50) is brought from the closed position (P11) to the released position (P21) by enabling the button release.

33. The method according to any one of claims 28 to 30, wherein, The method includes the following steps: -Detect the first load receiving of the first drive motor (18) of the first cutter head block (40); -Detect the second load receiving of the second drive motor (20) of the second cutter head block (42); - The fault of the biaxial shredder (1) is determined based on the detected first load acceptance and second load acceptance.

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