Screwed knife holder

Abstract

The invention relates to a comminution rotor comprising: a shaft which can be driven in a direction of rotation about a rotation axis for comminution of waste; at least one holding device provided on the shaft for holding a comminution tool, wherein the holding device is detachably fastened to the shaft by at least one screw connection; wherein the shaft and the holding device have respective mutual contact surfaces and the contact surfaces of the shaft comprise a support surface and a first bearing surface, and wherein the contact surfaces of the holding device comprise a counter-support surface in contact with the support surface and a first counter-bearing surface in contact with the first bearing surface, wherein the first bearing surface is arranged behind the support surface with respect to the direction of rotation and a first angle, on the shaft material side, between the support surface and the first bearing surface is 90° or less than 90°;and wherein the contact surfaces of the shaft and the contact surfaces of the holding device are designed such that, in a screwed state of the holding device, there is at least partially a positive connection between the holding device and the shaft.;

Description

Field of the invention

[0001] The invention relates to a comminution rotor and a comminution device with a comminution rotor. State of the art

[0002] For the industrial shredding of waste (domestic waste, commercial waste, waste wood, etc.), shredders with rotating shredding shafts are used. The shredding shafts are equipped with tools called knives. Depending on the very diverse tasks involved in shredding waste, these can be made of very different shapes and materials. These can be cuboid blocks or blocks with various shapes (with cutting angles, clearance angles, etc.) that are advantageous for the shredding task. The knives are usually made of highly wear-resistant materials, some of which are also hardened.

[0003] The knives are typically attached to knife holders, which are welded, screwed, or part of a rotor, using screws. Depending on the shredding stage in a waste processing plant, more or less impurities (non-shreddable materials, such as large metal pieces) can enter the shredding / cutting process. These can primarily lead to breakages in the knives, and subsequently damage to the knife holder. This can be so damaged, for example, compressed, that a knife can no longer be attached to it.

[0004] EP 3 290 120 B1 describes a rotor for a shredding machine with detachably attached knife holders.

[0005] If a knife holder is not welded to the rotor or directly part of the rotor, but is attached with screws, it can be replaced after damage by loosening the screw connection and replacing it with a new knife holder with a new screw connection. However, this poses problems in that the knife or knife holder can be torn off under high loads (for example, due to screws breaking), or that the knife holder can become deformed if it becomes blocked by foreign matter, making it virtually impossible to disassemble. Description of the invention

[0006] The object of the invention is to avoid or at least mitigate the disadvantages mentioned.

[0007] The solution according to the invention is defined by a comminution rotor with the features according to claim 1.

[0008] The invention thus discloses a comminution rotor comprising: a shaft which can be driven in a rotational direction for comminution of waste about a rotational axis; at least one holding device provided on the shaft for holding a comminution tool, wherein the holding device is releasably fastened to the shaft by at least one screw connection; wherein the shaft and the holding device have respective mutual contact surfaces and the contact surfaces of the shaft comprise a support surface and a first bearing surface, and wherein the contact surfaces of the holding device comprise a counter-support surface in contact with the support surface and a first counter-bearing surface in contact with the first bearing surface, wherein the first bearing surface is arranged behind the support surface with respect to the direction of rotation and a first angle, on the shaft material side, between the support surface and the first bearing surface is 90° or less than 90°;and wherein the contact surfaces of the shaft and the contact surfaces of the holding device are designed such that, in a screwed state of the holding device, there is at least partially a positive connection between the holding device and the shaft.;

[0009] Due to the positive connection between the holding device and the shaft in conjunction with an angle of 90° or less than 90° between the support surface and the first bearing surface, when the holding device is loaded by material to be shredded against the direction of rotation during operation of the shredding rotor, the screw connection is subjected to less or no load compared to an angle of more than 90°. The angle of 90° or less than 90° between the support surface and the first bearing surface of the shaft reduces or prevents the effect of a torque on the holding device due to the shredding forces due to the positive connection of the mutual contact surfaces of the shaft and the holding device. A small remaining load on the screw connection results essentially from the deformation or elasticity of the material (e.g. steel) of the holding element and / or the shaft.

[0010] A further development of the system according to the invention is that the first angle between the support surface and the first bearing surface can be in the range of 50° to 85°, in particular between 60° and 80°. This improves the positive connection of the mutual contact surfaces of the shaft and the holding device to the support surface.

[0011] According to another embodiment, the at least partially positive connection between the holding device and the shaft can prevent rotation of the holding device about a contact area located at the rear end of the holding device with respect to the direction of rotation. This allows large torques to be avoided on the holding device and its screw connection.

[0012] Another refinement is that the contact surfaces of the shaft can include a second bearing surface, and the second bearing surface can be arranged in front of the support surface with respect to the direction of rotation. This improves the positive contact between the shaft and the holding device.

[0013] The first and second support surfaces can each comprise a flat surface. This simplifies the installation and replacement of the retaining device on the shaft because it only involves a movement along the support surfaces to separate or connect / bring the mutual contact surfaces on the support surface into contact.

[0014] The respective flat surfaces of the contact surface and the counter-contact surface can be parallel to each other, in particular offset by a height perpendicular to the flat surfaces.

[0015] The support surface and the counter-support surface can be flat surfaces.

[0016] According to another embodiment, the first and second bearing surfaces can be connected to each other via the support surface. This ensures the most complete possible contact between the shaft and the holding device.

[0017] Another refinement involves the mutual contact surfaces of the shaft and the retaining device consisting only of flat surfaces. This simplifies the manufacture of the respective contact surfaces as well as the assembly and disassembly of the retaining elements on the shaft.

[0018] According to another embodiment, the contact surfaces of the shaft can be formed directly on or in the shaft. This emphasizes that the contact surfaces are not provided on intermediate elements between the holding device and the shaft.

[0019] Another development consists in that the at least one screw connection is provided in a front region of the holding device in relation to the direction of rotation in front of the support surface, and in combination with the developments which have a second support surface, is also provided in the second support surface of the shaft.

[0020] According to another embodiment in combination with the embodiments that have a second support surface, a second angle between a longitudinal axis of at least one screw of the at least one screw connection and the second support surface in the direction of rotation can be 90° or less than 90°. This results in a good positive connection, since the retaining element is pressed against the support surface by the screw.

[0021] This can be further developed so that the second angle can be in the range of 50° to 85°, especially between 60° and 80°. This further improves the form fit.

[0022] Another refinement involves providing an additional screw connection between the holding device and the shaft in a rearward region of the holding device in the direction of rotation, behind the support surface. This provides better fixation of the holding element to the shaft, particularly on the side facing away from the side with the shredding tool.

[0023] According to another embodiment, the shredding tool can comprise a knife with one or more cutting elements, or the shredding tool can comprise a tearing tool with one or more tearing elements. In particular, the knife can comprise a cuboid block or a block with different cutting angles and / or clearance angles. This provides shredding tools suitable for waste.

[0024] Another refinement consists in the provision of a plurality of holding devices for holding a respective comminution tool on the shaft. The respective contact surfaces of the shaft and the respective contact surfaces of the holding device can be configured such that an individual one of the plurality of holding devices can be removed from the shaft and placed on the shaft when the screw connection is loosened. Holding devices arranged adjacent to one another in the axial direction of the shaft can each be slightly offset in the circumferential direction of the shaft in order to move past them one after the other in the case of a static counter-blade arranged in the axial direction.

[0025] The invention further relates to a shredding machine for shredding waste, in particular domestic waste, commercial waste, or waste wood, comprising one, two, or more shredding rotors according to the invention or one of the developments. The shredding machine further includes a drive device for driving the shredding rotor(s).

[0026] The training courses mentioned can be used individually or combined as required.

[0027] Further features and exemplary embodiments, as well as advantages of the present invention, are explained in more detail below with reference to the drawings. It is understood that the embodiments do not exhaust the scope of the present invention. It is further understood that some or all of the features described below can also be combined with one another in other ways. Drawings

[0028] Fig. 1 shows details of an embodiment of the crushing rotor according to the invention in cross-section. Fig. 2 corresponds Fig. 1 and illustrates geometric aspects. Fig. 3 shows a complete cross-section of the shredding rotor according to Fig. 1 and 2 Fig. 4 shows a perspective view of the holding device from above. Fig. 5 shows a perspective view of the holding device from below. Fig. 6 shows a perspective view of a section of the shaft. Fig. 7 shows a perspective view of the shredding rotor.

[0029] The same reference symbols in the drawings refer to identical or corresponding components. Embodiments

[0030] Fig. 1 and Fig. 2 shows details of an embodiment of the comminution rotor according to the invention in cross section.

[0031] The shredding rotor 10 comprises a shaft 1. This shaft is for shredding waste around a rotation axis in one direction of rotation (see Fig. 2 ) by a drive device (not shown) (e.g., electric motor or combustion engine). Holding devices 2 are provided on the shaft for holding a respective comminution tool 4, each holding device 2 being releasably attached to the shaft 1 by a screw connection 3a, 3b.

[0032] The shaft 1 and the holding device 2 have respective mutual contact surfaces 1a, 2a; 1b, 2b; 1c, 2c. The contact surfaces of the shaft 1 comprise a support surface 1c and a first bearing surface 1a, wherein the first bearing surface 1a is arranged behind the support surface 1c with respect to the direction of rotation. The contact surfaces of the holding device 2 comprise a counter-support surface 2c and a first counter-bearing surface 2a.

[0033] A first, shaft material-side angle α between the support surface 1c and the first bearing surface 1a (between the surfaces, within the material of the shaft) is in this embodiment less than 90°, e.g., in the range of 50° to 85°, in particular between 60° and 80°. The angle α is repeated in the holding element 2 on the free space side (without material of the holding element) between the counter contact surfaces 2a and 2c (see also Fig. 5 ).

[0034] The contact surfaces 1a, 1b, 1c of the shaft and the contact surfaces 2a, 2b, 2c of the holding device 2 are designed such that in a screwed state of the holding device 2 (as in Fig. 1 and 2 shown) there is at least partially a positive connection between the holding device 2 and the shaft 1.

[0035] In this embodiment, the contact surfaces of the shaft 1 comprise a second bearing surface 1b, which is arranged in front of the support surface 1c with respect to the direction of rotation. The contact surfaces of the holding device 2 comprise a second counter-bearing surface 2b. This improves the positive contact between the shaft 1 and the holding device 2.

[0036] The first and second support surfaces 1a, 1b each comprise a flat surface that is parallel to one another and spaced apart by a distance h perpendicular to the flat surfaces. This simplifies the assembly and replacement of the holding device 2 on the shaft 1 because these processes merely involve moving the holding device 2 along the support surfaces 1a, 1b to separate the mutual contact surfaces on the support surface / counter-support surface from one another or to connect / bring them into contact with one another.

[0037] A second angle β between a longitudinal axis of at least one screw 3b of the "front" screw connection 3b and the second support surface 1b in the direction of rotation is less than 90°. The second angle β can be in the range of 50° to 85°, in particular between 60° and 80°. This results in a good positive connection, since the retaining element 2 is pressed against the support surface 1c by the screw 3b.

[0038] A further screw connection 3a between the holding device 2 and the shaft 1 is provided in a rear region of the holding device 2, in the direction of rotation, behind the support surface 1c or counter-support surface 2c. This achieves a better fixation of the holding element 2 on the shaft 1, particularly on the "rear" side, which faces away from the side with the shredding tool 4.

[0039] In Fig. 2a force F is shown acting on the comminution tool 4 due to the comminution process. If a foreign material (e.g. a metal part) becomes jammed, this can lead to very high forces with heavy loading of the holding element 2. Due to the angle α of the support surface 1c, the outwardly projecting force component, which results from a fictitious torque M on the holding element 2 due to the support at the rear around the end area P (edge ​​P) of the holding element 2 (at a distance r), is absorbed by the shape (support surface 1c and counter-support surface 2c) and not primarily by the fastening screws 3b at the front. This significantly reduces the forces acting on the screw connection 3b. If the holding element 2 becomes deformed, it can be easily replaced as a single element, as already described.

[0040] Fig. 3 shows a complete cross-section of the shredding rotor 10 according to Fig. 1 and2 .

[0041] The holding elements 2 (knife holders 2) with a respective shredding tool 4 (knife 4) are mounted directly on the shaft 1. The shredding tools 4 are located at the front of the holding elements 2, as seen in the direction of rotation (arrow) around the rotation axis A. There is contact between each holding element 2 and the shaft 1 at the respective contact surfaces 1a, 2a; 1b, 2b; 1c, 2c.

[0042] Fig. 4 and Fig. 5 shows a perspective view from above or below of a possible design of the holding device 2.

[0043] The essential features of the invention are the counter bearing surfaces 2a, 2b and the counter support surface 2c. Furthermore, openings / bores for the screw connections 3a, 3b (see Fig. 1 ) as well as openings / holes, 4a around the crushing tool 4 (see Fig. 1 and 3 ), especially screwing it on.

[0044] In Fig. 5 The end region of the retaining element 2 is shown with the edge P, around which the previously described fictitious torque M would act if the forces were not absorbed by the support surface or the counter-support surface 2c. At the edge P, the contact between the counter-support surface 2a of the retaining element 2 and the previously described support surface 1a of the shaft 1 ends.

[0045] Fig. 6 shows a perspective view of a section of shaft 1.

[0046] The shaft 1 provides bearing surfaces 1a and 1b, as well as a support surface 1c, for each retaining element. The bearing surfaces 1a and 1b are flat surfaces that are parallel to each other and spaced apart by a distance h.

[0047] Fig. 7 shows a perspective view of the complete shredding rotor.

[0048] A plurality of holding devices 2 are provided on the shaft 1 for holding a respective comminution tool 4. The respective contact surfaces of the shaft 1 and the respective contact surfaces of the holding device 2 are designed such that a single one of the plurality of holding devices 2 can be removed from the shaft 1 and placed onto the shaft 1 when the screw connection 3a, 3b is loosened.

[0049] Holding devices 2 arranged next to one another in the axial direction of the shaft 1 can be offset slightly in the circumferential direction of the shaft 1 in order to move past it one after the other in the case of a static counter-blade arranged in the axial direction. In this way, a scissor-like cutting process can be achieved.

[0050] A summary of the invention and its advantages is presented again below in connection with an embodiment of a waste shredding device (shredder), with reference to elements of the drawings.

[0051] The challenge of a screwed, replaceable knife holder 2 is to ensure easy replacement even after damage from foreign matter, while ensuring that the rotor 1 is not damaged in the process. For easy replacement, a weight of less than 25 kg is also advantageous, allowing replacement by a qualified person without the need for lifting equipment.

[0052] The invention is intended for shredders equipped with one, two, or more rotors (shredding shafts) and preferably having only one direction of rotation as the working direction. One or more blade holders 2, to which the blades 4 are fastened, can be placed on a rotor 1. The invention represents the screw connection 3a, 3b of the blade holder 2 via one or more screws in combination with a form-fitting contour (support surface 1c). The form-fitting contour is designed such that the radial forces occurring on the blade holder when a foreign material crashes are absorbed by this contour to such an extent that the fastening screws 3b of the blade holder 2 only have to absorb a small portion of the forces.Due to the angle α of the support surface 1c, the outwardly projecting force component, which results from a fictitious torque M of the knife holder 2, due to the rear support, is absorbed by the shape and not primarily by the fastening screws 3b at the front. At the same time, the form fit is designed so that it only works for one direction of rotation of the shredding rotor. In addition to the support surface 1c, the knife holder 2 rests on the bearing surfaces 1a, 1b. This provides the advantage of easy disassembly via essentially radial displacement of the knife holder 2.

[0053] The size and shape of the support surface 1c, which represents the positive connection, can be directly adapted to the forces occurring. The support surface 1c is preferably designed in the axial direction, i.e., approximately parallel to the rotor axis. Preferably, an appropriate angle α of the contact surface 1a relative to the support surface 1c is selected, for example, 70°, which defines the loads on the screw connection 3b. Alternatively, a screw connection 3a can also be installed at the rear, whereby the front screw connection 3b of the blade holder 2 is system-relevant.

[0054] The front screw connection 3b is ideally designed with an angle β, which can be e.g. 70° to 80° or less, relative to the support surface 1b, thus ensuring a play-free contact between the support surface 1c of the rotor 1 and the counter support surfaces 2c of the knife holder 2.

[0055] The illustrated embodiments are merely exemplary and the full scope of the present invention is defined by the claims.

Claims

1. A comminution rotor (10), comprising: a shaft (1) which is drivable in one direction of rotation about a rotation axis (A) for comminution of waste; at least one holding device (2) provided on the shaft for holding a comminution tool (4), wherein the holding device (2) is detachably attached to the shaft by at least one screw connection (3b);wherein the shaft (1) and the holding device (2) have respective mutual contact surfaces (1a-c, 2a-c), and the contact surfaces of the shaft comprise a support surface (1c) and a first bearing surface (1a), and wherein the contact surfaces of the holding device (2) comprise a counter-support surface (2c) in contact with the support surface (1c) of the shaft (1) and a first counter-bearing surface (2a) in contact with the first bearing surface (1a) of the shaft (1), wherein the first bearing surface (1a) is arranged behind the support surface (1c) with respect to the direction of rotation and a first, shaft material-side angle (α) between the support surface (1c) and the first bearing surface (1a) is 90° or less than 90°; and wherein the contact surfaces (1a-c) of the shaft (1) and the contact surfaces (2a-c) of the holding device (2) are designed such that, in a screwed state of the holding device (2), there is at least partially a positive connection between the holding device (2) and the shaft (1); 2. Crushing rotor according to claim 1, wherein the first angle (α) between the support surface (1c) and the first bearing surface (1a) is in the range of 50° to 85°, in particular between 60° and 80°.

3. Crushing rotor according to claim 1 or 2, wherein the at least partially positive connection between the holding device (2) and the shaft (1) prevents rotation of the holding device about a contact area (P) between the holding device and the shaft located at the rear end of the holding device with respect to the direction of rotation.

4. Crushing rotor according to one of claims 1 to 3, wherein the contact surfaces of the shaft (1) comprise a second support surface (1b) and the second support surface is arranged in front of the support surface (1c) with respect to the direction of rotation, and wherein the contact surfaces of the holding device (2) comprise a second counter support surface (2b) in contact with the second support surface (1b) of the shaft (1).

5. Crushing rotor according to claim 4, wherein the first and the second support surface each comprise a flat surface (1a, 1b), and / or wherein the first and the second counter support surface (2a, 2b) each comprise a flat surface (2a, 2b).

6. Crushing rotor according to claim 5, wherein the first and the second support surface (1a, 1b) are parallel to one another, in particular offset by a height (h) perpendicular to the flat surfaces (1a, 1b), and / or wherein the first and the second counter support surface (2a, 2b) are parallel to one another, in particular offset by the height (h).

7. Crushing rotor according to one of claims 1 to 6, wherein the mutual contact surfaces (1a-c, 2a-c) of the shaft and the holding device consist only of flat surfaces.

8. Crushing rotor according to one of claims 1 to 7, wherein the contact surfaces (1a-c) of the shaft are formed directly on or in the shaft (1).

9. Crushing rotor according to one of claims 1 to 8, wherein the at least one screw connection (3b) is provided in a front region of the holding device (2) in front of the support surface (1c) with respect to the direction of rotation, and in combination with one of claims 4 to 6 is also provided in the second support surface (1b) of the shaft (1).

10. Crushing rotor according to claim 9 in combination with one of claims 4 to 6, wherein a second angle (β) between a longitudinal axis of at least one screw of the at least one screw connection (3b) and the second support surface (1b) in the direction of rotation is 90° or less than 90°.

11. Crushing rotor according to claim 10, wherein the second angle (β) is in the range of 50° to 85°, in particular between 60° and 80°.

12. Crushing rotor according to one of claims 9 to 11, wherein a further screw connection (3a) is provided between the holding device (2) and the shaft (1) in a rear region of the holding device in the direction of rotation behind the support surface (2c).

13. Comminution rotor according to one of claims 1 to 12, wherein the comminution tool (4) comprises a knife with one or more cutting elements or wherein the comminution tool (4) comprises a tearing tool with one or more tearing elements, wherein the knife in particular comprises a cuboid block or a block with different cutting angles and / or clearance angles.

14. A comminution rotor according to one of claims 1 to 13, wherein a plurality of holding devices (2) for holding a respective comminution tool (4) is provided on the shaft; wherein the respective contact surfaces of the shaft and the respective contact surfaces of the holding device are designed such that an individual one of the plurality of holding devices can be removed from the shaft and placed onto the shaft when the screw connection is loosened.

15. A shredding machine for shredding waste, in particular domestic waste, commercial waste, or waste wood, comprising: one, two, or more shredding rotors (10) according to one of claims 1 to 14; and a drive device for driving the shredding rotors (10).

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