Tool Assembly for A Comminuting Apparatus

Abstract

A tool assembly for a comminuting apparatus having knives secured to the periphery of a comminuting rotor is provided including an integral knife carrier adapted to be secured to the comminuting rotor of the comminuting apparatus having a supporting surface for support against a seat formed at the rotor and an abutment face with a non-threaded through bore extending therefrom. The assembly includes a knife detachably secured to the knife carrier, a screw connection between the knife and knife carrier, and a screw bolt extending through the through bores of the knife and the knife carrier, wherein a screw nut is screwed onto a portion of the screw bolt extending beyond a trough bore of the knife carrier for clamping the knife to the knife carrier.

Claims

1. A tool assembly for a comminuting apparatus having knives secured to the periphery of a comminuting rotor, comprising: an integral knife carrier adapted to be secured to the comminuting rotor of the comminuting apparatus, and having a supporting surface for support against a seat formed at the rotor and an abutment face with a non-threaded through bore extending therefrom; a knife detachably secured to the knife carrier, having at least three lateral boundary faces and two bases, wherein at least one of the two bases is adapted to be a working face having a plurality of cutting edges, and wherein at least two cutting edges intersect at a cutting tip, and wherein the knife has a non-threaded through bore extending between both bases and having a countersink, in particular in the form of a conical expansion, at the working face; wherein the knife directly or indirectly abuts the abutment face of the knife carrier with one of both bases, and the through bore of the knife carrier and the through bore of the knife are aligned to each other; a screw connection between the knife and knife carrier, comprising a screw bolt extending through the through bores of the knife and the knife carrier with a conical head abutting the countersink of the bore at the working face of the knife, wherein a screw nut is screwed onto a portion of the screw bolt, extending beyond the trough bore of the knife carrier, for clamping the knife to the knife carrier.

2. The tool assembly as claimed in claim 1, characterised in that the working face of the knife is formed concavely to provide curved cutting edges.

3. The tool assembly as claimed in claim 1 or 2, characterised in that the other base of the knife is also adapted to be a working face having a plurality of cutting edges, and respective two cutting edges intersect at a cutting tip, and the bore has a conical expansion at the other base.

4. The tool assembly as claimed in claim 3, characterised in that both working faces of the knife have radii of curvature different from each other.

5. The tool assembly as claimed in any one of claims 1 to 4, characterised in that the screw bolt abuts the knife only with its conical head.

6. The tool assembly as claimed in any one of claims 1 to 5, characterised in that the knife carrier has a cylindrical depression around its through bore at the side facing away from the knife, with at least a portion of the screw nut extending therein.

7. The tool assembly as claimed in any one of claims 1 to 6, characterised in that boundary faces of the knife carrier shadow the threaded end of the screw bolt in the rotor's direction of movement.

8. The tool assembly as claimed in any one of claims 1 to 7, characterised in that a positive-fit anti-rotation mechanism is provided between the shaft of the screw bolt and the knife carrier.

9. The tool assembly as claimed in claim 8, characterised in that the shaft of the screw bolt is formed with positive-fit surfaces in the cross section, in particular polygonal, extending axially over a predetermined distance, and the bore of the knife carrier within this longitudinal portion has complementary positive-fit surfaces, in particular having a complementary polygonal shape, to provide a positive fit between the screw bolt and knife carrier.

10. The tool assembly as claimed in claim 9, characterised in that a key or close tolerance pin is disposed, each extending in a keyway or mating bore, respectively, within the screw bolt and knife carrier.

11. The tool assembly as claimed in any one of claims 1 to 10, characterised in that the screw nut has a sleeve-like base body, having a threaded portion and a tool-engaging portion axially adjacent thereto directly or via an axial connecting portion, wherein the tool-engaging portion has an axial mount for providing tool abutment faces, in particular in the form of a hexagon socket.

12. The tool assembly as claimed in claim 11, characterised in that, between the threaded portion and tool-engaging portion, an intermediate base portion is disposed, extending perpendicularly to the axis of the sleeve-like base body.

13. The tool assembly as claimed in any one of claims 1 to 12, characterised in that, between the knife carrier and knife, an adapter plate is disposed for adapting the abutment face of the knife to the abutment face of the knife carrier.

14. A comminuting rotor for a comminuting apparatus, comprising at least one tool assembly as claimed in any one of claims 1 to 13.

15. A knife for a tool assembly as claimed in any one of claims 1 to 13, wherein the knife has at least three, in particular four, lateral boundary faces and two bases, and wherein at least one of the two bases is adapted to be a working face having a plurality of cutting edges, and at least two cutting edges intersect at a cutting tip, and wherein the knife has a non-threaded through bore extending between both bases and having a countersink, in particular in the form of a conical expansion, at the working face, and the knife is directly or indirectly abuttable against the abutment face of the knife carrier with one of both bases, and the through bore of the knife carrier and the knife are able to be aligned to each other.

16. The knife as claimed in claim 15, characterised in that the working face of the knife is formed concavely to provide curved cutting edges.

17. The knife as claimed in claim 15 or 16, characterised in that the other base of the knife is also adapted to be a working face having a plurality of cutting edges, and respective two cutting edges intersect at a cutting tip, and the through bore also has a countersink at the other base.

18. The knife as claimed in claim 15, 16 or 17, characterised in that the knife comprises a hard metal, in particular being formed as a solid hard metal knife.

Description

[0027] The invention will now be illustrated by describing several embodiments with reference to the appended drawings in which

[0028] FIGS. 1A-1D show a first embodiment of a knife configured to be used in a tool assembly of the invention in a perspective view FIG. 1A, a front view FIG. 1B, a rear view FIG. 1C and a sectional view FIG. 1D;

[0029] FIGS. 2A-2D show another embodiment of a knife configured to be used in a tool assembly of the invention in a perspective view FIG. 2A, a front view FIG. 2B, a rear view FIG. 2C and a sectional view FIG. 2D;

[0030] FIGS. 3A-3D show an embodiment of a knife carrier configured to be used in a tool assembly of the invention for detachably securing a knife according to FIGS. 1-2 to a comminuting rotor of a comminuting apparatus in a perspective view FIG. 3A, a front view FIG. 3B, a rear view FIG. 3C and a sectional view FIG. 3D;

[0031] FIG. 4 shows the arrangement of a tool assembly of the invention, comprising a knife carrier according to FIG. 3A to which a knife according to FIG. 2A is detachably secured via a screw connection, on a comminuting rotor in a sectional view;

[0032] FIG. 5 shows the arrangement of a tool assembly of the invention, comprising a knife carrier according to FIG. 3A to which a knife according to FIG. 1A is detachably secured via a screw connection, at a comminuting rotor in a sectional view;

[0033] FIG. 6 shows the arrangement of another embodiment of a tool assembly of the invention on a comminuting rotor in a sectional view; and

[0034] FIG. 7 shows another tool assembly of the invention secured to a comminuting rotor in a sectional view, which comprises an adapter plate in addition to the components of FIGS. 4, 5 and 6.

[0035] FIGS. 1A-1D and FIGS. 2A-2D each show an embodiment of a knife for a comminuting apparatus for use in a tool assembly of the invention which may as such be able to be secured to a comminuting rotor, for example using screws or by welding.

[0036] In the embodiment described, knife 10 of FIGS. 1A-1D, also known as a cutting crown, is configured as a prism having two bases 11, 12 defined by four cutting edges 14A-14D and 16A-16D, respectively. Respective two of these cutting edges intersect at a cutting tip 15A-15D or 17A-17D. As both bases provide cutting edges, they are herein referred to as working faces. In this embodiment, knife 10 has flat bases 11, 12 and flat lateral faces 13A-13D disposed perpendicularly thereto. For securing the knife, it has a through bore 18 which is smooth on the inside, i.e. does not have a thread. To receive a conical head of a screw bolt, a conical expansion 19A, 19B is provided on both working faces, i.e. on both bases 11, 12. This can best be seen in the sectional view of FIG. 1D showing a section, including the bore axis and extending in parallel to lateral faces 13B and 13D. In this embodiment, both bases are formed as identically configured working faces.

[0037] The knife according to FIGS. 2A-2D is first of all different from the knife according to FIG. 1A-1D in that the front base 21 is concavely curved such that two respective concave cutting edges 24A-24D intersect at a respective cutting tip 25A-25D. When the knife is used, these tips engage the material to be comminuted like hooks due to the concave paths of the cutting edges, resulting in an aggressive comminution. Again, the working face, here base 21, has a conical expansion or depression 29 at through bore 28. As a further difference to knife 10 according to FIGS. 1A-1D, rear base 21 of knife 20 is not configured as a working face, therefore not having a depression at bore 28, see FIG. 2C.

[0038] In the embodiment described, to detachably secure the knives to the comminuting rotor, a single integral knife carrier 50 is provided for each knife, see FIGS. 3A-3D, FIG. 3A showing the knife carrier in a perspective view, FIG. 3B showing the knife carrier in a front view against the rotor's direction of rotation, FIG. 3C showing a rear view of the knife carrier, and FIG. 3D showing the knife carrier in a sectional plane including the axis of a through bore 52 of the knife carrier and oriented in parallel to the surface normal of abutment face 51.

[0039] In the embodiment described, knife carrier 50 is welded into a milled seat at the rotor, wherein the seat may be configured as a V-shaped recess at the rotor. At its rear surface facing away from the knife, knife carrier 50 comprises a, e.g. cylindrical, depression 54 around bore 52. Top boundary face 55 shades the area of depression 54, which will be discussed further below. As can be seen from the front view of FIG. 3B and the sectional view of FIG. 3D, another depression 53 is provided at the front of the knife carrier, i.e. at abutment face 51 at the bore, here having polygonal boundary faces, in particular in the form of a hexagon socket.

[0040] FIG. 4 shows a sectional view of the arrangement of a knife 20 as described above which is detachably secured to a knife carrier 50 by a screw connection, the knife carrier being itself welded onto a comminuting rotor 100 of a comminuting apparatus, the sectional plane being perpendicular to the axis of the comminuting rotor and the axis of a through bore 52 (see FIG. 3D) of a knife carrier 50 extending in the sectional plane.

[0041] As can be seen from FIG. 4, knife 20 abuts flat abutment face 51 of knife carrier 50 with its rear flat base 22. A screw bolt 60 extends from the knife side across through bore 28 of the knife and through bore 52 of knife carrier 50 and exits therefrom with its threaded portion 63 in the area of depression 54 of knife carrier 50. A screw nut 70 axially closed on one side by an intermediate base portion 71 is screwed onto bolt thread 63 of the screw bolt. Screw nut 70 abuts knife carrier 50 via a split washer 80 to clamp knife 20 to knife carrier 50. Screw bolt 60 has a conical screw head 61 with a circumferential surface 62 which entirely, i.e. over a circumference of 360°, abuts conical expansion 29 of knife 20.

[0042] In the embodiment described, adjacent screw head 61, the shaft of screw bolt 60 is configured with a polygonal, here hexagonal, cross section which, when the tool assembly is in its assembled state, extends into the area of positive-fit surfaces 53 of knife carrier 50, see FIG. 3D. The complementarily formed positive-fit surfaces in portion 64 of screw bolt 60 correspond to positive-fit surfaces 53 of knife carrier 50, thus providing a positive fit between the screw bolt and knife carrier which prevents the screw bolt to be turned within knife carrier 50, making it easier to secure and detach the knife to and from the knife carrier.

[0043] In the example described, on the side of intermediate base portion 71 of screw nut 70 facing away from thread 72, the nut has tool abutment faces formed as hexagon socket surfaces one of which is indicated by reference number 73 in FIG. 4. External circumferential surface 74 of screw nut 70 protects these tool abutment faces against the impact of material to be comminuted to provide for easy insertion of a corresponding tool, here a hexagon key, to unscrew screw nut 70. Accordingly, top boundary face 55 of knife carrier 50 is further sloped to shadow screw bolt 60 and screw nut 70 in direction of rotation R of the comminuting rotor from the material to be comminuted.

[0044] FIG. 5 shows another embodiment of a tool assembly configured according to the invention and secured to a rotor 100 in a sectional view corresponding to the illustration of FIG. 4. The knife is formed identically to knife 10 described above with reference to FIG. 1. The only difference compared to the embodiment shown in FIG. 4 is that knife 10 is not configured to be concave at its working face, but flat like at its abutment face 51.

[0045] FIG. 6 shows another embodiment of a tool assembly configured according to the invention and again secured to a rotor 100 in a sectional view corresponding to the illustration of FIG. 4. With respect to base 21, knife 20′ is formed identically to knife 20 described above with reference to FIG. 2. The only difference is the configuration of base 22 which is not flat in this case, but identical to that of base 21. Accordingly, base 22′ is configured as a concave working face with concavely curved cutting edges, respective two of which intersect at a cutting tip. As explained above with reference to base 21, base 22′ also has a conical expansion 29′ in the area of through bore 28, having the same function as the conical expansion 29 of abutment face 21. Complementarily to concave working face 22′ of knife 20′, abutment face 51′ of knife carrier 50′ is configured such that knife 20′ abuts knife carrier 50′ across its entire working face 22′. The further configuration of knife carrier 50′ and knife 20′ corresponds to that of knife carrier 50 and knife 20 of FIG. 4, respectively, and will therefore not be described any further. The configuration of the tool assembly according to FIG. 6 has the advantage that, upon wear of the currently active cutting edge or associated cutting tip, knife 20′ can not only be rotated about the axis of through bore 28 after unscrewing the screw connection to increase service life. In addition, knife 20 can be inverted such that the base initially acting as the abutment face against the knife carrier serves as the working face after inverting the knife. Accordingly, the base of the knife initially used as the working face then abuts the knife carrier.

[0046] FIG. 7 shows another configuration of a tool assembly for securing to a rotor 100. What is installed is a knife 20′ which is identical to the knife described with reference to FIG. 6. In addition, knife carrier 50 is structured identically to knife carrier 50 of FIG. 4. In order to provide for an adaptation of flat abutment face 51 to concave base 22′ of knife 20, an adapter plate 90 is provided which has a flat abutment face 91 facing the knife carrier and a curved, here convex, abutment face 92 facing knife 20′. Both in the configuration according to FIG. 6 and that according to FIG. 7, both screw bolt 60 and screw nut 70 are formed identically to those of FIG. 4. The implementation according to FIG. 7 is particularly suitable for such applications in which a comminuting rotor is equipped with non-detachably attached knife carriers 50 which are to be provided with knives that can be used with both sides.

LIST OF REFERENCE NUMBERS

[0047] 10 Knife [0048] 11, 12 Base [0049] 13A-13D Lateral face [0050] 14A-14D Cutting edges [0051] 15A-15D Cutting tips [0052] 16A-16D Cutting edges [0053] 17A-17D Cutting tips [0054] 18 Through bore [0055] 19A, 19B Conical expansion [0056] 20, 20′ Knife [0057] 21, 22, [0058] 22′ Base [0059] 23A-23D Lateral face [0060] 24A-24D Cutting edge [0061] 25A-25D Cutting tip [0062] 26A-26D Cutting edge [0063] 27A-27D Cutting tip [0064] 28 Through bore [0065] 29, 29′ Conical expansion [0066] 50, 50′ Knife carrier [0067] 51, 51′ Abutment face [0068] 52 Through bore [0069] 53 Positive-fit surface [0070] 54 Depression [0071] 55 Sloped surface [0072] 60 Screw bolt [0073] 61 Screw head [0074] 62 Conical surface [0075] 63 Threaded portion [0076] 64 Circumferential positive-fit portion [0077] 70 Screw nut [0078] 71 Intermediate base portion [0079] 72 Thread [0080] 73 Tool abutment face [0081] 74 External circumferential surface [0082] 80 Split washer [0083] 90 Adapter plate [0084] 91 Flat abutment face [0085] 92 Convex abutment face [0086] 100 Comminuting rotor [0087] R Direction of rotation