PLANT FOR SHREDDING METAL WASTE, AXLE USABLE IN SUCH A PLANT AND DISC USABLE IN SUCH A AXLE

Description

Field of the invention

[0001] The present invention generally relates to the field of plant engineering and it particularly relates to a metal waste shredding plant, as well as an axis and a disc which can be used in such plant.State of the Art

[0002] Conventional waste shredding plants generally comprise shredding means such as a plurality of counter-rotating axes designed to shred waste.

[0003] As schematically illustrated in FIG. 1A, each axis A comprises a plurality of discs D equally spaced and staggered with respect to the adjacent axis A so that upon rotating the axes, the lateral faces F of the discs D face each other and they are substantially at contact with each other.

[0004] In particular, each disc D comprises a central portion integrally joined with a rotary shaft and a plurality of peripheral cutting modules M which can be removably coupled with the central portion by means of a high number of through screws.

[0005] Therefore, the material is deposited on the plane defined by the axes A and it is cut by the lateral faces F of the cutting modules M with an action similar to that of a pair of scissors.

[0006] Even a reduced consumption or a simple bevelling of the lateral faces F jeopardises the cutting efficiency of the discs D and therefore the shredding efficacy of the plant.

[0007] In this case it is therefore necessary to replace the entire disc D or at least the worn-out cutting modules M.

[0008] Therefore, replacing a disc D requires stopping the plant, removing the axis A, removing all the discs D until one reaches the worn or damaged disc, replacing it with a new disc and refitting all the discs D on the axis A.

[0009] On the other hand, disassembling one or more modules M requires stopping the plant and operating directly therein. In particular, the operator must act on the plurality of screws, generally 9-12 screws, of each module M to remove and replace it.

[0010] This operation is particularly difficult both because of the working conditions in the middle of sharp waste residues, as well as due to the size and weight of each individual module M.

[0011] This drawback is even more serious considering that the operator has to work suspended above the screening plane, especially when it comes to reaching the central discs D. Disadvantageously, the discs D positioned centrally on the axis A wear out faster than those positioned in proximity of the ends of the axis A.

[0012] Furthermore, the modules M have a particularly high cost due to the materials used and require appropriate expensive disposal processes.

[0013] In any case, the operations of replacing the discs D or the modules M are particularly slow and require a machine downtime amounting to several days, generally one week.

[0014] In the industry, it is therefore known to wait for a considerable number of discs to wear out before carrying out maintenance so as to reduce the operations of stopping the machine as much as possible.

[0015] A further drawback is therefore that the plant operates with a reduced shredding efficacy for different time, even for months.

[0016] Document US 2003122006 shows a plant which uses discs having a central module and a pair of lateral cutting modules coupled to the former. From US 2003122006 is known a disc having all the features of the preamble of the independent claim 1.

[0017] The drawback of these discs lies in complicating maintenance and / or replacement of the discs or of part thereof.

[0018] A further drawback of the plant described in this document lies in the fact that it is not particularly effective, in particular in relation to the fact that the waste remains blocked on the discs and wrap around them.Summary of the invention

[0019] An object of the present invention is to at least partly overcome the drawbacks illustrated above by providing a metal waste shredding plant that is highly efficient and cost-effective.

[0020] An object of the present invention to provide a metal waste shredding plant with minimum maintenance costs and times.

[0021] An object of the present invention is to at least partly overcome the drawbacks illustrated above by providing a disc that is highly efficient and cost-effective.

[0022] Another object of the present invention to provide a disc easy to maintain.

[0023] Another object of the present invention to provide a disc that avoids the blocking of the material around it.

[0024] These and other objects that will be more apparent hereinafter, are attained by a disc according to claim 1, an axis according to claim 14 and a plant according to claim 15.

[0025] The dependent claims describe advantageous embodiments of the invention.Brief description of the drawings

[0026] Further characteristics and advantages of the invention will be more apparent in light of the detailed description of a preferred but non-exclusive embodiment of the invention, illustrated by way of non-limiting example with reference to the attached drawings, wherein: FIG. 1A is an axonometric view of a pair of counter-rotating axes A with a plurality of discs D of the state of the art with FIG. 1B showing an enlargement of FIG. 1A which schematically shows a detail of the disc D; FIG. 2 is an axonometric view of a disc 100 according to the invention; FIGS. 3 and 4 are a partially exploded axonometric view of the disc 100; FIG. 5 is an axonometric view of a plant 1 with a plurality of axes 10. Detailed description of a preferred embodiment

[0027] With reference to the aforementioned figures, herein described is a plant 1 for shredding waste, and, in particular, for shredding metal waste.

[0028] In a per se known manner, the plant 1 may comprise: an inlet 2 for metal waste S to be shredded; an outlet 3 for the shredded metal waste S; a working chamber 4 interposed between the inlet 2 and the outlet 3; means 5 for shredding metal waste arranged in the working chamber 4; and drive means 6, for example a diesel or electric engine, operatively connected to the shredding means 5.

[0029] Suitably, the shredding means 5 may comprise at least one axis 10 operatively connected with the drive means 6 so that the latter activate the former. In particular, the shredding means 5 may comprise a plurality of axes 10.

[0030] The axes 10 may be configured in a manner such that two adjacent axes 10 are counter-rotating with respect to each other. Each axis 10 may comprise a shaft 101 and a plurality of discs 100 keyed onto the shaft 101.

[0031] The discs 100 may therefore be coupled to the shaft 101 so as to rotate with the latter around a rotation axis X. Preferably, the shaft 101 may define such rotation axis X.

[0032] Suitably, the shaft 101 may be shaped, while the disc 100 comprises a central portion 110, the latter may comprise a counter-shaped inner surface 111. For example, the shaft 101 may have a hexagonal cross-section and the inner surface 111 may also be hexagonal, as schematically illustrated in FIG. 2.

[0033] In particular, the discs 100 of an axis 10 may have a distance along the shaft 101 substantially equal to the width of the disc 100. Furthermore, the distance between two adjacent shafts 101 may be substantially smaller than the diameter of the discs 100, while the discs 100 of two adjacent shafts 101 may be mutually staggered so that during use, that is during rotation of the axes 10, the discs 100 have respective lateral faces 120 facing each other or at contact.

[0034] In this manner, the counter-rotation of two adjacent shafts 101 may promote the cutting and therefore the shredding of the metal waste.

[0035] This cutting action may be mainly carried out by the lateral faces 120, and in particular by the outer edges 121 thereof.

[0036] In particular, the lateral faces 120 of the disc may define a plane π substantially perpendicular to the axis X. On the other hand, the disc 100 may comprise an outer surface 130 substantially perpendicular to said plane π . Such surface 130 may be designed to come into contact with the waste.

[0037] In other words, the outer surface 130 and the lateral faces 120 may define the edges 121 which may be sharp-edged. In greater detail, an edge of about 90° may be provided for interposed between the outer surface 130 and the lateral faces 120 defining the edge 121.

[0038] According to the invention, the disc 100 comprises a plurality of cutting modules 150 which are coupled with the central portion 110 peripherally thereto.

[0039] For example, the central portion 110 may have a hexagonal inner surface 111 and a pentagonal outer surface 112. It is clear that such surfaces have a polygonal shape considering a section in the plane π .

[0040] Should the outer surface 112 have a pentagonal section, it may therefore comprise five sections 112'. Suitably, each cutting module 150 may comprise a lower surface 151 which may remain facing or at contact with one of the sections 112'. In other words, should the outer surface 112 be pentagonal, five cutting modules 150 may be provided for.

[0041] The cutting modules 150 may be coupled to the central portion 110 in a per se known manner, for example by means of screw-and-nut means 190. For example, a plurality of screws may be provided for, while both the central portion 110 and the cutting module 150 may comprise a plurality of radial holes 116.

[0042] Suitably, upon coupling the modules 150 and the central portion 110, each of the latter may have respective lateral faces 153, 113 which may cooperate to define the lateral faces 120 of the disc.

[0043] Advantageously, the lateral faces 153, 113 may be substantially flush so that the lateral surface 120 of the disc 100 is substantially planar and continuous.

[0044] This characteristic may allow to prevent the waste from being blocked between the discs and wrapping around them.

[0045] Furthermore, thanks to this characteristic, the outer surface 130 of the disc 100 may be in proximity of the opposite shaft 101. As a matter fact, thanks to the planarity of the lateral surfaces 120, in use, the surfaces 120 of discs of two adjacent axes 10 may remain in proximity, almost at contact, so as to prevent the waste from being interposed between two discs 100, jeopardising the shredding efficacy and / or jeopardising the durability of the discs 100.

[0046] The lateral face 153 of the cutting module 150 may therefore comprise the cutting edge 121.

[0047] In other words, the cutting modules 150 may interact with the metal waste S so as to shred the latter.

[0048] According to the invention, each module comprises a central element 155 and a pair of lateral elements 157 which may be removably coupled with the central element 155 on opposite sides thereof.

[0049] In greater detail, as schematically illustrated in FIG. 3, the central element 155 may comprise a pair of opposite lateral faces 155', 155", while the lateral element 157 may comprise a respective pair of opposite lateral faces 157', 157".

[0050] The lateral elements 157 may therefore be coupled on opposite sides with respect to the central element 155, so that the face 157' of the former is arranged thereat or at contact with the face 155' of the central element 155 and so that the face 157" of the latter is arranged thereat or at contact with the face 155" of the central element 155. On the other hand, the face 157" of the former and the face 157' of the latter may define the respective lateral faces 153 of the cutting module 150.

[0051] Suitably, the outer lateral faces 157', 157" of the lateral elements 157 may be flush with the outer surface 113 of the central portion 110 so as to define the flat surface 120 with the advantages described above.

[0052] In other words, the lateral face 120 of the disc 100 may comprise the outer face 157" or 157' of the lateral element 157 depending on how the latter is positioned. Preferably, a lateral face 120 may comprise the lateral face 157" while the opposite face 120 may comprise the lateral face 157'.

[0053] In any case, the lateral elements 157 may have a thickness s7 substantially smaller than the thickness s5 of the central elements 155. It is clear that the total thickness of the disc 100 may be equal to the sum of the thickness s7 of two lateral elements 157 and to the thickness s5 of the central element 155.

[0054] The lateral elements 157 and the elements 155 may be coupled by means of a screw-and-nut means 191 of the per se known type.

[0055] For example, the lateral elements 157 may comprise a plurality of through holes 158 while the central elements 155 may comprise a plurality of holes 156. The holes 158 and 156 may therefore be mutually configured so that upon coupling the lateral elements 157 and the central elements 155, the respective holes 156, 158 are arranged thereat.

[0056] The holes 158 may be through holes. In this manner, a plurality of screws 191 may be provided passing through the holes 158 and interacting with the holes 156 and may therefore be internally threaded.

[0057] The holes 156 may be blind. In this case, each face 155', 155" may comprise a plurality of blind holes 156 for coupling a respective lateral element 157. Possibly, also the holes 156 may be of the passing through type so as to simplify the operations for manufacturing the central element 155.

[0058] Preferably, both the holes 156 and the holes 158 may have respective axes substantially parallel to the axis X.

[0059] Suitably, each central module 155 and each lateral portion 157 comprises a respective upper surface 131, 132. In particular, the surfaces 131 and 132 may cooperate to define the outer surface 152 of the module 150, that is, the surface designed to interact with the waste.

[0060] It is clear that the outer surfaces 152 of two or more modules 150 may cooperate to define the outer surface 130 of the disc 100.

[0061] On the other hand, the central modules 155 and the lateral portions 157 comprise respective lower surfaces 134, 135 opposite the upper surfaces 131, 132 which may remain facing the central portion 110 of the disc 100 to define the inner surface 151 of the module 150.

[0062] Advantageously, the surface 131 of the central module 155 is without seats for the screws. In this manner, the outer surface 131 is substantially continuous.

[0063] This characteristic may allow to prevent the waste from being blocked on the surface, causing malfunctions of the system, for example wrapping around the disc 100.

[0064] Preferably, also the surface 132 of the lateral elements 157 may be without seats for the screws. In this manner, the outer surface 131 may be substantially continuous.

[0065] According to a particular aspect of the invention, the entire outer surface 152 may be without seats for the screws and therefore continuous. Preferably, the entire outer surface 130 may be substantially continuous.

[0066] It is clear that the outer surface 131 or the surface 152 may be flat although it may have any dents or cuts due to the shredded waste. As a matter fact, the expression continuous surface is used to indicate that this surface is without seats for the screws 190 and therefore that the fastening screws 190 are not accessible from the external.

[0067] Suitably, the holes 116 of the central portion 110 may be through holes, while the holes of the cutting module 150 may be blind. The holes 116 of the central portion 110 and of the cutting module 150 may be mutually configured so that upon positioning the cutting modules 150 on the surface 112', the respective holes are arranged thereat.

[0068] Advantageously, the head of the screws 190 may remain inside the central portion 110, that is at the surface 111, and it may therefore remain protected from dirt and waste. This will allow to prevent the materials from sealing the head of the screw 190 due to the high pressures, preventing or making it difficult to unscrew it in the event of maintenance and / or replacement of a module 150.

[0069] According to a further aspect of the invention, the surfaces 131 and 132 may be flush irrespective of whether the surface 131 is without the screw seats. Due to these characteristics, the outer surface 152 may be substantially flat. In other words, the outer surface 152 may be without steps or grooves considering a plane substantially perpendicular to the plane π passing through the axis X, that is, an axial plane of the disc 100. Suitably, the entire outer surface 130 may be substantially flat.

[0070] This will allow to prevent the waste from being blocked on the disc 100, jeopardising the operation of the plant, for example promoting the wrapping of the waste around the disc 100.

[0071] It is clear that the outer surface 130 may have a substantially planar extension although, due to wear, the surface 130 may have cuts or dents.

[0072] On the other hand, as shown in the attached drawings, the surface 152 along a radial plane parallel to π may have a non-circular profile and it may have a shape which may for example comprise a cusp, or other interruptions such as steps, although not shown in the attached figures.

[0073] In other words, when the surfaces 131, 132 are flush, the outer surface 130 may be flat, while when the screws 190 are positioned inside, the outer surface 130 may be substantially continuous, that is, without the holes for the screws so that - in use - the heads of the screws 190 are inside as described above.

[0074] Advantageously, the surface 130 may be continuous and flat with all the advantages described above.

[0075] Preferably, the central elements 155 and the lateral elements 157 may have the same height and width and they may have a different thickness. In particular, the central elements 155 and the lateral elements 157 may have the same shape considering a section in the plane π or a plane parallel thereto.

[0076] Furthermore, the cutting modules 150 may all be identical to each other. Upon coupling the lateral elements 157 to the central element 155, the outer lateral surface 157" and 157' of the former may be substantially flush with the lateral faces 113 so as to cooperate with the latter to define the lateral faces 120 of the disc 100.

[0077] Furthermore, according to a particular aspect of the invention the lateral elements 157 may comprise the cutting edge 121.

[0078] In other words, the lateral elements 157 may define the part of the disc 100 which is subject to greater wear.

[0079] Therefore, the characteristics described above allow to remove a single lateral element 157 of a single cutting module 150 in order to replace it in case of wear of the cutting edge 121.

[0080] Possibly, the position of two cutting modules 157 may also be inverted with respect to the central element 155. As a matter fact, the face 157" of a first module and the face 157' of the opposite module, that is the outer faces, may wear out during use.

[0081] For example, with reference to FIG. 3, the screws 190 may therefore be removed, and the right and left lateral elements may be inverted. Therefore, the worn-out face 157" of the right lateral element 157 may abut against the face 155" of the central element and the face 157' not worn out may remain outside. Similarly, the left lateral element 157 may have the respective worn-out face 157' facing the face 155' and the face 157" not worn-out facing outwards.

[0082] Advantageously, the lateral elements 157 may be made of a particularly hard material. For example, special steel for tools, hardened steel, nitrided steel or other steel of the per se known type may be used for the production of disc cutting modules of shredding plants.

[0083] Suitably, the lateral elements 157 and the central elements 155 may be made of materials different from each other. In particular, the lateral elements 157 may be made of a material which is harder than the central elements 155.

[0084] Therefore, only the lateral elements 157 subjected to wear may be made of hard and expensive material, while the central elements 155 may be made of cheaper and lighter materials.

[0085] Furthermore, the lateral elements 157 may be easier to handle due to the small dimensions and weights thereof with respect to a whole disc 100.

[0086] Furthermore, advantageously, the characteristics described above allow to carry out maintenance on the disc 100, for example one or more lateral elements 157 may be replaced, without having to remove the disc 100 from the shaft 101 or to completely remove the cutting module 150.

[0087] As a matter fact, this operation for replacing or inverting the lateral elements 157 may be carried out simply by stopping the axis 10 and by acting on the disc 100 positioned on the shaft 101.

[0088] The cutting modules 150 may be coupled to the central portion 110 by means of radial screws 190 as described above, or by means of radial screws positioned so as to allow access from the outer surface 130, for example as shown in FIG. 1B of the state of the art.

[0089] Suitably, in any case, the radial screws 190 may be arranged at the central element 155 only. This will allow to easily replace or change the position of lateral elements 157, while the central element 155 may remain in position and which may be replaced much less frequently.

[0090] It is clear that the lateral elements 157 may be displaced on different discs 100 and not only from one side of the disc 100 to the other. For example, the lateral elements 157 of the discs 100 positioned centrally on the shaft 101 may wear out more than the peripheral ones. Therefore, this may allow to change one or more lateral elements 157 with the discs 100 positioned along the shaft 101 without having to remove all the discs 100.

[0091] In the light of the above, it is clear that the invention attains the pre-set objectives.

[0092] The invention is susceptible to numerous modifications and variants. All details may be replaced by other technically equivalent elements, and the materials may be different depending on the technical needs, without departing from the scope of protection of the invention defined by the attached claims.

Claims

1. A disc which can be used in a metal waste shredding plant which can be coupled with a rotary shaft (101) to rotate therewith, the disc comprising: - a central portion (110) designed to interact with the shaft (101) to rotate integrally joined therewith around a rotation axis (X); - a plurality of cutting modules (150) coupled with said central portion (110) peripherally thereto, said cutting modules (150) being designed to interact with the metal waste during use; wherein each of said cutting modules (150) comprises a central element (155) and a pair of lateral elements (157) which can be removably coupled with said central element (155) on opposite sides with respect to the latter; wherein said central element (155) and said pair of lateral elements (157) respectively comprise a first and second lower surface (134, 135) facing said central portion (110) and a first and second opposite upper surface (131, 132); characterized in that said first upper surface (131) of said central element (155) is without seats for fastening screws so as said first upper surface (131) is continuous.

2. Disc according to claim 1, wherein said first and second upper surface (131, 132) cooperate to define a third outer surface (152) of said cutting modules (150), the latter being continuous.

3. Disc according to claim 2, wherein said third outer surfaces (152) of said cutting module (150) cooperate to define a fourth outer surface (130) of the disc (100), the latter being continuous.

4. Disc according to claim 1, 2, or 3, wherein said third outer surface (152) and / or said fourth outer surface (130) is without seats for fastening screws.

5. Disc according to the preceding claim, wherein said central portion (110) comprises a first plurality of through holes (116) and said plurality of cutting modules (150) comprises a second plurality of blind holes (116), said first and second holes (116) being arranged mutually corresponding to house a plurality of fastening screws (190).

6. Disc according to any one of the preceding claims, wherein said first and second upper surface (131, 132) cooperate to define said third outer surface (152) of said cutting modules (150), said first and second upper surface (131, 132) being substantially flush so that said outer surface (152) is flat.

7. Disc according to the preceding claim, wherein said third outer surfaces (152) of said cutting modules (150) cooperate to define a fourth outer surface (130) of the disc (100), the latter being flat.

8. Disc according to claim 6 or 7, wherein said central elements (155) and said lateral elements (157) have the same shape considering a section in planes perpendicular to said rotation axis (X).

9. Disc according to the preceding claim, wherein said central elements (155) and said lateral elements (157) of said cutting modules (150) have an identical height and width and a different thickness.

10. Disc according to any one of the preceding claims, comprising a fifth substantially planar lateral surface (120), each of said fifth lateral surfaces (120) defining a plane (π) substantially perpendicular to said axis (X).

11. Disc according to the preceding claim, wherein said cutting modules (150) and said central portion (110) respectively comprise a pair of first and second opposite lateral faces (153, 113), the first and second lateral face (153, 113) of each pair being substantially flush to define said fifth flat lateral surface (120) of the disc (100).

12. Disc according to claim 11, wherein said central elements (155) and said lateral elements (157) have respective third lateral faces (155', 155", 157', 157"), the latter having a surface - substantially identical to each other - one of said third faces (157', 157") of said lateral elements (157) defining said second lateral face (153) of said cutting modules (150).

13. Disc according to claim 11 or 12, wherein each of said lateral elements (157) comprises a pair of fourth opposite lateral faces (157', 157"), upon coupling said lateral elements (157) with said central element (155), said fourth opposite lateral faces (157", 157') of the former being flush with said second lateral faces (113) of said central portion (110) so as to cooperate mutually to define said fifth flat lateral surface (120) of the disc (100).

14. An axis which can be used in a metal waste shredding plant comprising: - a rotary shaft (101) defining a longitudinal axis (X); - a plurality of discs (100) according to one or more of the preceding claims coupled with said rotary shaft (101) to rotate therewith.

15. A metal waste shredding plant, comprising: - at least one inlet (2) for the metal waste to be shredded; - at least one outlet (3) for the shredded metal waste; - at least one working chamber (4) interposed between said at least one inlet (2) and said at least one outlet (3); - means (5) for shredding the metal waste arranged in said working chamber (4); - drive means (6) operatively connected to said shredding means (5); wherein said shredding means comprise at least one axis (10) according to the preceding claim.