Screw-type crushing tool

Abstract

The invention relates to a crushing device comprising a shaft that can be selectively driven in one of two opposite directions of rotation in order to crush material. For this purpose, the crushing device also comprises a holding device provided on the shaft; a one-piece crushing tool that acts in both directions of rotation and that is fastened on the holding device by means of at least one screw running in a radial direction of the shaft; wherein the holding device and the crushing tool have mutual contact surfaces that are designed such that, when the screw is removed, the crushing tool can be placed onto the holding device by radial movement towards the shaft and can be removed from the holding device by radial movement away from the shaft; and wherein the contact surfaces are furthermore designed such that, in a state when the crushing tool is screwed with the screw, there is at least partially a form-fitting connection that prevents a movement of the crushing tool relative to the holding device both in the two directions of rotation and in axial directions of the shaft.

Description

[0001] SCREWED SHREDDING TOOL

[0002] Field of the invention

[0003] The invention relates to a comminution device.

[0004] State of the art

[0005] For the industrial shredding of waste (domestic waste, commercial waste, scrap wood, etc.), shredders with rotating shredding shafts equipped with knives, rippers, teeth, or similarly designated tools are used. Very different shredding tools are used for the very diverse tasks involved in shredding waste. For coarse pre-shredding (e.g., granules <400 to <150 mm), ripper teeth with a larger radial extension than axial extension are advantageous.

[0006] Depending on the type of waste, shredding tools are subject to varying degrees of wear. Worn shredding tools must be reconditioned within the machine or by removing the shredding shafts, or they can be replaced using replaceable solutions (e.g., bolted parts). Replaceable shredding or cutting tools ideally have a limited weight (e.g., <25 kg) so that they can be replaced by a service person without the need for a lifting device, and they can be replaced in a reasonably short time.

[0007] Screwed wear parts in small dimensions have advantages over large wear parts, as they do not require complex machining (e.g. by welding) in order to be used again.

[0008] A single-piece shredding tool is primarily used for a single rotation direction of the shredding shaft. Changing the shredding shaft's rotation direction is not intended for shredding in this case, but is often used when the shredding shaft is blocked due to foreign matter or overload, or when material needs to be rearranged for better shredding. For small gap widths in the range of 0-2 mm between the rotating tool and the stationary part, the shredding tools are also called knives, and for large gap widths in the range of 10 mm or more, they are also called rippers.

[0009] Crushing tools which have a larger radial extension than axial and are intended to be suitable for both directions of rotation are usually welded to the crushing shaft.

[0010] An example of interchangeable shredding tools is shown in DE 10 2005 026816 A1, featuring the option of lateral screwing using multiple screws. The disadvantage here is the poor accessibility and the necessary large number of screws, resulting in a complex replacement scenario. The shredding forces, at least the lateral ones, must be largely absorbed by the screws.

[0011] Description of the invention

[0012] The object of the invention is to avoid or at least mitigate the disadvantages mentioned.

[0013] The solution according to the invention is defined by a comminution device having the features according to claim 1.

[0014] The invention thus discloses a comminution device comprising a shaft that can be selectively driven in one of two opposing directions of rotation in order to comminute material. The comminution device further comprises a holding device provided on the shaft; a one-piece comminution tool that acts in both directions of rotation and is fastened to the holding device by at least one screw running in a radial direction of the shaft; wherein the holding device and the comminution tool have mutual contact surfaces that are designed such that, when the screw is removed, the comminution tool can be placed on the holding device by radial movement toward the shaft and can be removed from the holding device by radial movement away from the shaft.and wherein the contact surfaces are further designed such that, when the comminution tool is screwed to the screw, there is at least partially a positive connection which prevents movement of the comminution tool relative to the holding device both in the two directions of rotation and in the axial directions of the shaft.;

[0015] With such a shredding device, it is possible to fix a one-piece shredding tool by means of a radially positioned screw on the shredding shaft via the holding device in such a way that the shredding device is suitable for both directions of rotation.

[0016] In particular, the contact between the shredding tool and the holding device is achieved only (exclusively) via the positive connection with the contact surfaces.

[0017] A further development of the system according to the invention consists in that the contact surfaces of the holding device can have a front and a rear flank in the direction of rotation. The front and rear flanks can be formed symmetrically to the radial direction with respect to an angle of inclination. In this case, an angle between the radial direction and the contact surfaces of the front and rear flanks can be in the range of 5° to 40°, preferably between 10° and 30°. In other words, the angle between the flanks can be in the range of 10° to 80°, preferably in the range of 20° to 60°. Alternatively, the front and rear flanks can be formed asymmetrically with different angles between the radial direction and the contact surfaces, preferably each in the aforementioned range of 5° to 40°, preferably between 10° and 30°.

[0018] According to another development, the contact surfaces of the holding device can be formed directly on or in the shaft.

[0019] Alternatively, the holding device may comprise a comminution tool holder which is welded to the shaft or screwed to the shaft, wherein the contact surfaces of the holding device are formed on the comminution tool holder or wherein the contact surfaces of the holding device are formed partly on the comminution tool holder and partly on or in the shaft.

[0020] Another development consists in that the contact surfaces can be V-shaped or spherical in a cross-section parallel to the axial direction of the shaft, whereby a lateral, axial displacement of the comminution tool relative to the holding device can be prevented, in particular during operation of the comminution device.

[0021] According to another development, the contact surfaces can be at least partially V-shaped or spherical in a radial cross-section, whereby, in particular during operation of the comminution device, a comminution force (tearing or cutting force) acting in the circumferential direction has a component perpendicular to the contact surface, which component can be greater than a component parallel to the contact surface.

[0022] Another further development is that the crushing tool can be designed symmetrically to a central, radial direction with respect to the two directions of rotation.

[0023] According to another development, the comminution tool can have at least one central, radial opening, in particular a bore, for passing through the at least one screw.

[0024] Another further development is that during operation of the shredding device, a frictional contact can be effected at least partially on the front contact surfaces in the direction of rotation.

[0025] The frictional contact can reduce the tensile load on at least one screw.

[0026] According to another development, the shredding tool can have one or more cutting elements. These cutting elements can be formed in the shredding tool and, depending on the intended use, can be lugs, hooks, and / or edges of the shredding tool. Another development is that the shredding tool can have a greater extension in the radial direction than in the axial direction. This is particularly suitable for applications where a clearance is provided between several shredding tools on the shaft.

[0027] The invention further relates to a cold milling machine with a shredding device as described above, which is suitable for milling material in both directions of rotation. For example, it can be used to remove asphalt, concrete, or gravel layers of varying thickness.

[0028] The invention further relates to a waste shredding device suitable for shredding waste in both directions of rotation. The shredding device comprises: one shredding device as described above; or two shredding devices as described above, which can be driven in the same or opposite directions of rotation. Such a shredding device can be used for shredding waste, such as household waste, commercial waste, waste wood, etc.

[0029] The training courses mentioned can be used individually or combined as required.

[0030] 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.

[0031] Drawings

[0032] Fig. 1 shows a perspective view of the shredding device. Fig. 2 shows a cross-section of the shredding device.

[0033] Fig. 3 shows a perspective exploded view of the shredding device.

[0034] Fig. 4 shows a combination of components of the

[0035] Shredding device without shredding tool.

[0036] Fig. 5 shows a welding of the components from Fig. 4 without

[0037] Shredding tool.

[0038] The same reference symbols in the drawings refer to identical or corresponding components.

[0039] Embodiments

[0040] Fig. 1 shows a perspective view of the comminution device according to the invention.

[0041] The comminution device 10 comprises a shaft 1, which can be selectively driven in one of two opposing directions of rotation. The comminution device 10 further comprises a holding device 2 provided on the shaft 1; a one-piece comminution tool 3 acting in both directions of rotation, which is fastened to the holding device 2 by at least one screw 4 running in a radial direction of the shaft 1; wherein the holding device 2 and the comminution tool 3 have mutual contact surfaces 1a, 2a, 3a (see Fig.3) which are designed such that the comminution tool 3, when the screw 4 is removed, can be placed onto the holding device 2 by radial movement towards the shaft 1 and can be removed from the holding device 2 by radial movement away from the shaft 1; and wherein the contact surfaces 1a, 2a, 3a are further designed such that, when the comminution tool 3 is screwed to the screw 4, there is at least partially a positive connection.

[0042] The comminution tool 3 can be a ripping tool (ripper) or a cutting tool (knife). The positive connection of the comminution tool 3 to the holding device 2 is designed such that movement of the comminution tool 3 relative to the holding device 2 is prevented both in the two directions of rotation and in the axial directions of the shaft 1.

[0043] Fig. 2 shows a cross section of the crushing device 10.

[0044] The contact surfaces of the holding device 2 have a front flank FV and a rear flank FH in the direction of rotation, which are formed symmetrically to the radial direction R. An angle W between the radial direction and the contact surfaces of the front and rear flanks FV, ​​FH can be in the range of 5° to 40°, preferably between 10° and 30°.

[0045] As shown in Fig. 2, a force K acting on the front flank FV (in the circumferential direction) has a component Ks perpendicular to the front flank FV and a component KP parallel to the front flank FV. The parallel component KP causes only a slight tensile load on the screw 4. In contrast, the vertical component Ks is completely absorbed by the holding device 2 via the contact surfaces of the front flank FV. Due to a frictional connection of the contact surfaces of the flank FV, the force acting on the screw 4 during operation of the comminution device 10 under load can be further reduced or completely avoided.

[0046] The same applies analogously to the flank designated FH in Fig. 2, which becomes the leading flank when the direction of rotation changes.

[0047] Fig. 3 shows a perspective exploded view of the shredding device 10.

[0048] The holding device 2, 2a, 1a comprises a comminution tool holder 2, which is welded to the shaft 1 or screwed to the shaft 1, wherein the contact surfaces 1a, 2a of the holding device 2, 2a, 1a are formed on the comminution tool holder 2 or wherein the contact surfaces 1a, 2a of the holding device 2, 2a, 1a are formed partially on the comminution tool holder 2 and partially on or in the shaft 1. The contact surfaces 1a, 2a, 3a are V-shaped or spherical in a cross-section parallel to the axial direction of the shaft 1, whereby a lateral, axial displacement of the comminution tool 3 relative to the comminution tool holder 2 can be prevented during operation of the comminution device 10.

[0049] The contact surfaces 1a, 2a, 3a are, for example, also at least partially V-shaped in a radial cross-section (alternatively spherical, U-shaped), whereby during operation of the comminution device 10 a tearing force acting in the circumferential direction has a component perpendicular to the contact surface which is greater than a component parallel to the contact surface (cf. description of Fig. 2).

[0050] Fig. 4 shows an assembly of components of the comminution device 10. The comminution tool has been omitted from the drawing.

[0051] The shaft 1 is pre-machined and has contact surfaces 1a. A crushing tool holder 2 with pre-machined contact surfaces 2a is mounted on it.

[0052] Fig. 5 shows a welding of the components from Fig. 4.

[0053] In this example, the crushing tool holder 2 is connected to the shaft 1 via one or more welds 5.

[0054] Finally, the crushing tool 3 is attached thereto by means of the threaded screw 4, wherein a counter thread is provided in the crushing tool holder 2 or the shaft 1.

[0055] A summary of the invention and its advantages is presented below again in connection with a waste shredding device (shredder).

[0056] The invention is particularly intended for shredders equipped with one, two, or more rotors (shredding shafts). The invention makes it possible for a one-piece shredding tool 3 to be fixed by means of a radially positioned screw 4 on the shredding shaft 1 via a knife holder 2 (referred to above as shredding tool holder 2) in such a way that it is suitable for both directions of rotation. The geometry of the shredding tool 3 can be designed in a wide variety of shapes outside of the contact surfaces. Due to the optimal accessibility, maintenance of the wearing parts on the shredding shaft can be carried out on-site by service personnel during short machine downtimes. A complex replacement of the entire shredding shaft is therefore not necessary. In the event of damage to the shredding tool 3, e.g.due to a foreign substance, this can be replaced quickly and easily without having to carry out major repairs in the machine or even having to replace the entire shredding shaft 2.

[0057] The positive connection between the screwable shredding tool 3 and the shredding shaft, optionally with a knife holder 2, supports the force distribution under loads from all directions, including lateral ones, so that the fastening screw only has to absorb a small portion of the shredding forces. All forces arising from the shredding process are dissipated either directly via the positive connection between the shredding tool 3 and the knife holder 2, or between the frictional connection between the shredding tool 3 and the knife holder 2, as well as a portion of the tensile load on the screw 4.

[0058] The positive connection is established exclusively via the contact surfaces 1a, 2a, and 3a. The contact surfaces are not flat, but are designed in a shape that prevents lateral slippage. The contact surfaces 1a, 2a, and 3a can be V-shaped, spherical, or have various other geometries outside of a flat surface. For manufacturing reasons, a V-shape is advantageous. The contact surfaces 1a and 2a can each be implemented in the shredding shaft 1 and the knife holder 2, or all in a larger knife holder, or only in one shredding shaft 1, which represents the contact surfaces 1a and 2a.

[0059] The shredding tool 3 is fastened by means of one or more screws 4. The screw connection results in a positive connection via the contact surfaces 1a, 2a and 3a, whereby the contact surfaces 1a and 2a, or only the contact surfaces 1a, or the contact surfaces 2a can rest on the shredding tool 3.

[0060] A prefabricated knife holder 2 can be welded directly onto the shredding shaft 1 or into a prefabricated pocket of the shredding shaft 1. The final finish of the contact surfaces 1a and 2a can be completed prior to welding or can be applied mechanically after the welded state. Alternatively, the knife holder 2 can also be screwed or manufactured as a single piece with the rotor.

[0061] The illustrated embodiments are merely exemplary and the full scope of the present invention is defined by the claims.

Claims

Patent claims 1. A comminution device comprising: a shaft which can be selectively driven in one of two opposite directions of rotation for comminution of material; at least one holding device provided on the shaft; a one-piece comminution tool which acts in both directions of rotation and is fastened to the holding device by at least one screw running in a radial direction of the shaft; wherein the holding device and the comminution tool have mutual contact surfaces which are designed such that, when the screw is removed, the comminution tool can be placed on the holding device by radial movement towards the shaft and can be removed from the holding device by radial movement away from the shaft.and wherein the contact surfaces are further designed such that, when the comminution tool is screwed to the screw, there is at least partially a positive connection between the comminution tool and the holding device, which prevents movement of the comminution tool relative to the holding device both in the two directions of rotation and in the axial directions of the shaft.; 2. Crushing device according to claim 1, wherein the contact surfaces of the holding device have a front and a rear flank in the direction of rotation, wherein in particular an angle between the radial direction and the contact surfaces of the front and rear flanks is in the range of 5° to 40°, preferably between 10° and 30°.

3. Crushing device according to claim 1 or 2, wherein the contact surfaces of the holding device are formed directly on or in the shaft.

4. Crushing device according to claim 1 or 2, wherein the holding device comprises a crushing tool holder which is welded to the shaft or screwed to the shaft, and wherein the contact surfaces of the holding device are formed on the crushing tool holder or wherein the contact surfaces of the holding device are formed partly on the crushing tool holder and partly on or in the shaft.

5. Crushing device according to one of claims 1 to 4, wherein the contact surfaces are V-shaped or spherical in a cross section parallel to the axial direction of the shaft, whereby a lateral, axial displacement of the crushing tool relative to the holding device is prevented, in particular during operation of the crushing device.

6. Crushing device according to one of claims 1 to 5, wherein the contact surfaces are at least partially V-shaped or spherical in a radial cross section.

7. Crushing device according to one of claims 1 to 6, wherein the crushing tool is designed symmetrically to the radial direction with respect to the two directions of rotation.

8. Crushing device according to one of claims 1 to 7, wherein the crushing tool has at least one central, radial opening, in particular a bore, for passing through the at least one screw.

9. Crushing device according to one of claims 1 to 8, wherein during operation of the crushing device, a frictional contact is effected at least partially on the front contact surfaces in the direction of rotation.

10. Crushing device according to claim 9, wherein the frictional contact reduces a tensile load on the at least one screw.

11. A comminution device according to any one of claims 1 to 10, wherein the comminution tool comprises a knife having one or more cutting elements or wherein the comminution tool comprises a tearing tool having one or more tearing elements.

12. Crushing device according to one of claims 1 to 11, wherein the crushing tool has a greater extent in the radial direction than in the axial direction.

13. Cold milling machine with a crushing device according to one of claims 1 to 12, which is suitable for milling material in both directions of rotation.

14. A waste shredding device suitable for shredding waste in both directions of rotation, comprising: a shredding device according to any one of claims 1 to 12; or two or more shredding devices according to any one of claims 1 to 12, which are drivable in the same or opposite directions of rotation.

Images