AU2018233052A1 - A Knife for a Stockfeed Mill - Google Patents

Abstract

A KNIFE FOR A STOCKFEED MILL A stockfeed mill 1 has a receptacle in the form of a generally rectangular prismatic bin 2 for receiving stockfeed 3 to be milled through an upward facing opening 4. A milling piece, in the form of a generally helical and spiralling vertical feed auger 5, is disposed within bin 2 for milling stockfeed 3. A tapered outlet 7 at the base of bin 2 directs the milled stockfeed 8 from auger 5. A drive train, in the form of a driven input shaft 9 for coupling to a PTO drive, and an associated transmission 10, transfer drive to auger 5. Auger 5 includes a central generally cylindrical hollow steel axle 11 that extends substantially vertically along an axis 12, and a continuous spiralling helical steel flighting 13 that extends axially along and radially outwardly from axle 11. The axle and flighting are, in use, driven via shaft 9 and transmission 10 to rotate counter clockwise. Fighting 13 supports three spaced apart like knives 15 that extend radially outwardly from the flighting. Knife 15 includes a mounting element, in the form of a generally straight steel mounting plate 21, which extends radially outwardly from auger 5. A blade 22 is removably mounted to plate 21, and has two cutting edges 23 and 24 that are formed from a metal with a hardness of at least HRC 55. A fastening element, in the form of a generally straight steel fastening plate 25, releasably and clampingly secures blade 22 to plate 21 to operatively expose cutting edge 23. Figure 1

Description

Description

2018233052 24 Sep 2018

A KNIFE FOR A STOCKFEED MILL 2016203438

FIELD OF THE INVENTION [0001] The present invention relates to a knife and in particular to a knife for a stockfeed mill.

[0002] The invention has been developed primarily for milling hay and other stock feeds for creating a feed ration for livestock and will be described hereinafter with reference to that application. However, it will be appreciated that the invention is not limited to these particular fields of use and is also applicable to milling or mulching grasses and other vegetation.

BACKGROUND [0003] Any discussion of the background art throughout the specification should in no way be considered as an admission that such art is widely known or forms part of common general knowledge in the field.

[0004] A variety of stockfeed mills for producing a feed ration from one or a range of livestock feed inputs are available and tend to fall into two main categories, being either stationary mills, or movable mills. The stationary mills are typically part of a milling plant and are often large in size to allow production of large quantities of the feed ration. These milling plants often include one or more of the following milling operations: grinding; hammer milling; shredding; and rolling. The movable mills, on the other hand, are typically mounted to a wheeled frame or base that is connectable in a conventional manner to a farm tractor. The tractor provides motive power both to move the mill between locations, and to drive the mill, where the latter occurs often via a standard PTO shaft.

[0005] In both stationary mills and movable mills there are two basic types. One is a mill designed for cutting or shredding hay or other fibrous feed material, and the other is a mill designed for mixing stockfeed and which also has a cutting or shredding function. In both cases the mills are known to include one or more of a vertical auger mixer, a horizontal auger mixer, and a reel mixer. These mixers are also known to include a plurality of spaced apart knives to facilitate the shredding and mixing actions undertaken.

[0006] Conventional mills are sometimes described as being configured to cut the feed material. However, as the blades used in these mills very quickly become blunt due to the abrasive nature of the feed material, any initial cutting action quickly reverts to a shredding action, in that the feed material is subject to a shearing action rather than a cutting action. In recognition of this, and in an attempt to extend the operational lifetime between knife

2018233052 24 Sep 2018 replacement, such knives are typically designed to have a low angle of approach to the feed material. A partial answer to the above limitation has been to make use of replaceable knives. These replaceable knives are fixed within the mill, typically by being bolted to an auger in the mill and are consumable or sacrificial elements. This approach requires more regular maintenance of the mill to allow for the removal of the dull or spent knives and their replacement with new knives. In an attempt to extend the maintenance intervals, knives are available with blades having serrated cutting edges. While this has some impact on the longevity of the knives, it is not significant.

[0007] Another approach to extending the maintenance intervals has been for the knives to include so called “self-sharpening” blades. These are assumed to be based upon using self-sharpening steel such as that included in earth moving implements. However, these steels do not tend to self-sharpen sufficiently when used for cutting fibrous material.

[0008] The inability of the prior art to overcome these disadvantages results in inefficient operation of the mills as they are required for significant periods between the replacement of the knives to shred or shear the feed material. This shredding is more energy intensive than cutting, is more prone to jamming, is susceptible to ejecting the feed material back though the inlet to the mill, gives rise to a less homogenous food ration and produces more fines and dust that can create health issues for personnel and for stock. [0009] Accordingly, there is a need in the art for an improved knife for a stockfeed mill.

SUMMARY OF THE INVENTION [0010] It is an object of the present invention to overcome or ameliorate at least one of the disadvantages of the prior art, or to provide a useful alternative.

[0011] According to a first aspect of the invention there is provided a knife for a stockfeed mill having a milling piece, the knife including:

a mounting element for extending from the piece;

a blade for removably mounting to the mounting element, the blade having a cutting edge with a hardness of at least HRC 55; and a fastening element for releasably securing the blade to the mounting element to expose the cutting edge.

[0012] In an embodiment the cutting edge is formed from a carbide.

[0013] In an embodiment the cutting edge is formed from a metal.

[0014] In an embodiment the cutting edge has a hardness of at least HRC 58.

[0015] In an embodiment the cutting edge has a hardness of at least HRC 60.

[0016] In an embodiment the metal is a tool steel.

2018233052 24 Sep 2018 [0017] In an embodiment the tool steel has a carbon content between 0.5% and 1.5%. [0018] In an embodiment the metal is a high speed steel.

[0019] In an embodiment the blade includes a plurality of cutting edges and less than all of the cutting edges are simultaneously operatively exposed when the blade is secured to the mounting element.

[0020] In an embodiment the milling piece, in use, is movable in the mill.

[0021] In an embodiment the milling piece, in use, is fixed in the mill.

[0022] In an embodiment the mill includes a receptacle for receiving stockfeed to be milled, the receptacle being defined at least in part by a sidewall that defines the milling piece.

[0023] In an embodiment the mill includes a further milling piece and, in use, the milling pieces move relative to each other.

[0024] In an embodiment the further milling piece is an auger.

[0025] In an embodiment the mounting element is releasably secured to the milling piece.

[0026] According to a second aspect of the invention there is provided a stockfeed mill having a milling piece from which extends one or more of the knives of the first aspect.

[0027] In an embodiment the stockfeed mill has a plurality of milling pieces each having at least one of the knives of the first aspect.

[0028] In an embodiment at least two of the milling pieces, in use, move relative to each other.

[0029] According to a third aspect of the invention there is provided a method for securing a blade to a milling piece for a stockfeed mill, the method including the steps of: providing a mounting element that extends from the piece;

removably mounting a blade to the mounting element, the blade having a cutting edge with a hardness of at least HRC 55; and releasably securing the blade to the mounting element with a fastening element to expose the cutting edge.

[0030] According to a fourth aspect of the invention there is provided a stockfeed mill having:

a receptacle for receiving stockfeed to be milled;

at least one milling piece disposed within the receptacle for milling the stockfeed; an outlet for directing the stockfeed from the milling piece;

a drive train for allowing drive to be transferred to the piece;

a plurality of spaced apart mounting elements that extend from the piece;

2018233052 24 Sep 2018 a plurality of blades for removably mounting to the respective mounting elements, each blade having a cutting edge with a hardness of at least HRC 55; and a fastening element for releasably securing the blades to the respective mounting elements to expose the cutting edges.

[0031] In an embodiment the fastening element includes a plurality of spaced apart fastening elements for engaging with respective blades.

[0032] In an embodiment the mounting elements are releasably mounted to the piece.

[0033] In an embodiment the mounting elements are individually releasably mounted to the piece.

[0034] In an embodiment the receptacle is defined at least in part by a sidewall and that sidewalls defines the piece.

[0035] According to a fifth aspect of the invention there is provided a method of milling stockfeed including the steps of:

providing a receptacle for receiving the stockfeed to be milled;

disposing a milling piece within the receptacle for milling the stockfeed; providing an outlet for directing the stockfeed from the milling piece;

providing a drive train for allowing drive to be transferred to the piece;

providing a plurality of spaced apart mounting elements that extend from the piece; removably mounting a plurality of blades to the respective mounting elements, each blade having a cutting edge with a hardness of at least HRC 55; and releasably securing the blades to the respective mounting elements with a fastening element to expose the cutting edges.

[0036] In an embodiment the step of securing the blades includes individually releasably securing the blades.

[0037] According to a sixth aspect of the invention there is provided a knife for a stockfeed mill having a milling piece, the knife including:

a mounting element for extending from the piece;

a blade for removably mounting to the mounting element; and a fastening element for releasably securing the blade to the mounting element. [0038] In an embodiment the fastening element clamplingly secures the blade to the mounting element.

[0039] In an embodiment the mounting element is integrally formed with the piece.

[0040] In an embodiment the mounting element is removably secured to the piece.

[0041] In an embodiment the mounting element includes a first abutment face and the blade includes a second abutment face that is abutted with the first abutment face when the blade is secured to the mounting element.

2018233052 24 Sep 2018 [0042] In an embodiment the first abutment face terminates at a first outer edge and the second abutment face extends beyond the first outer edge.

[0043] In an embodiment the fastening element includes a third abutment face and the blade includes a fourth abutment face that is abutted with the third abutment face when the blade is secured to the mounting element.

[0044] In an embodiment the third abutment face terminates in a second outer edge that substantially aligns with the first outer edge.

[0045] In an embodiment the mounting element includes a stop member that, in use, extends between the mounting element and the fastening element.

[0046] In an embodiment the stop member is fixedly secured to at least one of: the mounting element and the fastening element.

[0047] In an embodiment the stop member is integrally formed with at least one of: the mounting element and the fastening element.

[0048] In an embodiment the stop member is fixedly secured to both of the mounting element and the fastening element.

[0049] In an embodiment the mounting element and the fastening element are integrally formed.

[0050] In an embodiment the fastening element releasably clampingly secures the blade to the mounting element.

[0051] In an embodiment the fastening element releasably secures the blade to the mounting element in an interference fit.

[0052] In an embodiment the blade includes a cutting edge that is exposed when the blade is secured to the mounting element.

[0053] In an embodiment the blade includes a plurality of cutting edges and less than all of the cutting edges are operatively exposed when the blade is secured to the mounting element.

[0054] In an embodiment the blade includes two cutting edges, one of which is operatively exposed when the blade is secured to the mounting element.

[0055] According to a seventh aspect of the invention there is provided a method for securing a blade to a milling piece of a stockfeed mill, the method including the steps of: providing a mounting element that extends from the piece;

removably mounting the blade to the mounting element; and releasably securing the blade to the mounting element with a fastening element.

[0056] In an embodiment the blade includes a cutting edge and the method includes the prior step of forming the cutting edge from a tool steel or a carbide.

2018233052 24 Sep 2018 [0057] In an embodiment the prior step includes selecting the metal or carbide having a hardness of at least HRC 55.

[0058] In an embodiment the metal is a tool steel.

[0059] In an embodiment the metal is a high speed steel.

[0060] In an embodiment the blade is substantially wholly formed from the high speed steel.

[0061] Reference throughout this specification to “one embodiment”, “some embodiments” “an embodiment”, “an arrangement”, “one arrangement” means that a particular feature, structure or characteristic described in connection with the embodiment or arrangement is included in at least one embodiment or arrangement of the present invention. Thus, appearances of the phrases “in one embodiment”, “in some embodiments”, “in an embodiment”, “in one arrangement”, or “in and arrangement” in various places throughout this specification are not necessarily all referring to the same embodiment or arrangement, but may. Furthermore, the particular features, structures or characteristics may be combined in any suitable manner, as would be apparent to one of ordinary skill in the art from this disclosure, in one or more embodiments or arrangements. [0062] As used herein, and unless otherwise specified, the use of the ordinal adjectives first, second, third, etc., to describe a common object, merely indicate that different instances of objects in a class of objects are being referred to, and are not intended to imply that the objects so described must be in a given sequence, either temporally, spatially, in ranking, in importance or in any other manner.

[0063] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the art to which the invention belongs. The articles “a” and “an” are used herein to refer to one or to more than one (that is, to at least one) of the grammatical object of the article unless the context requires otherwise. By way of example, “an element” normally refers to one element or more than one element. In the claims below and the description herein, any one of the terms “comprising”, “comprised of” or “which comprises” is an open term that means including at least the elements/features that follow, but not excluding others. Thus, the term “comprising”, when used in the claims, should not be interpreted as being limitative to the means or elements or steps listed thereafter. For example, the scope of the expression “a device comprising A and B” should not be limited to devices consisting only of elements A and B. Any one of the terms “including” or “which includes” or “that includes” as used herein is also an open term that also means including at least the elements/features that follow the term, but not excluding others. Thus, “including” is synonymous with and means “comprising”.

2018233052 24 Sep 2018 [0066] As used herein, the term “exemplary” is used in the sense of providing examples, as opposed to indicating quality. That is, an “exemplary embodiment” is an embodiment provided as an example, as opposed to necessarily being an embodiment of exemplary quality.

BRIEF DESCRIPTION OF THE DRAWINGS [0067] Embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings in which:

Figure 1 is a schematic top perspective view of a stockfeed mill according to an embodiment of the invention;

Figure 2 is a perspective view of the milling piece used in the mill of Figure 1;

Figure 3 is an enlarged perspective view of one of the knives used in the mill of Figure 1;

Figure 4 is an exploded perspective view of an alternative knife for use in the mill of Figure 1;

Figure 5 is a cross-sectional view of part of the knife of Figure 4 taken along section line 5-5;

Figure 6(a) is a cross sectional view through another blade for use in the mill of Figure 1;

Figure 6(b) is a cross sectional view through another blade for use in the mill of Figure 1;

Figure 7 is a cross sectional view, similar to that of Figure 5, of a further embodiment of the invention;

Figure 8 is a cross sectional view, similar to that of Figure 5, of an even further embodiment of the invention;

Figure 9 is a cross sectional view of a blade having two cutting edges formed from a carbide;

Figure 10 is a cross sectional view of a further blade having a cutting edge formed from a carbide;

Figure 11 is a partial top view of the flighting of Figure 2 illustrating the angle of attack; and

Figure 12 is a perspective view of another milling piece.

2018233052 24 Sep 2018

DETAILED DESCRIPTION [0068] Described herein are a knife for a stockfeed mill, a stockfeed mill including one or more of those knives, and a method of milling stockfeed.

[0069] Referring to Figure 1 there is illustrated a stockfeed mill 1 having a receptacle in the form of a generally rectangular prismatic bin 2 for receiving stockfeed 3 to be milled through an upward facing opening 4. A milling piece, in the form of a generally helical and spiralling vertical feed auger 5, is disposed within bin 2 for milling stockfeed 3. A tapered outlet 7 at the base of bin 2 directs the milled stockfeed 8 from auger 5. A drive train, in the form of a driven input shaft 9 for coupling to a PTO drive of a tractor (not shown), and an associated transmission 10, transfer drive to auger 5. As best shown in Figure 2, auger 5 includes a central generally cylindrical hollow steel axle 11 that extends substantially vertically along an axis 12, and a continuous spiralling generally helical steel flighting 13 that extends axially along and radially outwardly from axle 11. The axle and flighting are, in use, driven via shaft 9 and transmission 10 to rotate counter clockwise when viewed from above. Flighting 13 supports three spaced apart like knives 15 that extend radially outwardly from the flighting. One of these knives is exemplarily illustrated in Figure 3 and will be described further. More particularly, knife 15 includes a mounting element, in the form of a generally flat and rectangular steel mounting plate 21, which extends radially outwardly from auger 5. A blade 22 is removably mounted to plate 21, and has two straight cutting edges 23 and 24 that are formed from a metal with a hardness of at least HRC 55. A fastening element, in the form of a generally flat and rectangular steel fastening plate 25, releasably and clampingly secures blade 22 to plate 21 to operatively expose cutting edge 23.

[0070] In other embodiments, such as that illustrated in Figure 12, where corresponding features are denoted by corresponding reference numerals having the suffix “a”, flighting 13a extends in the opposite sense to flighting 13 of the Figure 2 embodiment and rotates in a clockwise direction when viewed from above. The knives 15a in the Figure 12 embodiment are a mirror image of those knives 15 used in the Figure 2 embodiment such that the exposed cutting edges 23a lead the knife into milling engagement with the material being milled.

[0071] Mill 1 includes all of knives 15 being mounted to a movable milling piece. In other embodiments different or additional knives and/or milling pieces are used. More particularly, bin 2 includes a plurality of generally vertical connected sidewalls 28 that contain the milling piece in the form of auger 5. In one exemplary embodiment one or more of sidewalls 28 define a milling piece and one or more of knives 15 is mounted to

2018233052 24 Sep 2018 one of sidewalls 28 and extends radially inwardly toward auger 5. In other exemplary embodiments, all of the knives used are mounted to a stationary piece - such as one or more of the sidewalls - while in further embodiments a subset of the knives are mounted to one or more movable milling pieces and the remainder of the knives are mounted to one or more stationary milling pieces.

[0072] Mill 1 provided for illustration only, and includes only a single auger 5. In other embodiments multiple augers are used. For example, in those other embodiments one or more augers are included for milling, one or more augers are included for feeding hay or other material toward opening 4, and one or more augers are included for taking the milled stockfeed away from outlet 7. Some embodiments include axially parallel and spaced apart counter-rotating pairs of augers which support respective sets of knives 15 for cutting the material during the milling operation.

[0073] The spacing of knives 15 has regard to the type and form of the material being milled, as well as the balance of stresses on axle 11. For example, in other embodiments more than three knives are used, and these are equally circumferentially spaced to at least in part balance the forces exerted by the knives on axle 11 as the milling occurs. In other embodiments the circumferential spacing of knives 15 is less at the end of flighting 13 adjacent to input 4, and greater at the other end of flighting 13 that is adjacent to outlet 7. This arrangement takes into account that a greater amount of the milling, as provided by knives 15, will occur as the material to be milled is first received within bin 2. In other embodiments different knife spacing is used. For example, in one such embodiment the knives are arranged in pairs, where the knives in each pair extend diametrically outwardly from flighting 13.

[0074] In other mills use is also, or alternatively, made of augers (not shown) that extend along and rotate about a generally horizontal axis. In still further embodiments use is made of augers (not shown) that are inclined with respect to the horizontal. Knives 15 are able to be mounted to any one or more of these augers, or a sidewall adjacent to those augers, to facilitate the milling of stockfeed 3. In some mills use is made of a multistage milling process where the initial milling is implemented with a first auger having shorter knives 15, and then by a second auger having longer knives 15. In other embodiments use is made of like knives in both stages of the milling, with the knives for the first stage having a lower angle of approach (also referred to as a lower angle of attack) than the knives used in the second stage. In further mills the milling piece to which one or more of the knives are mounted is other than an auger or sidewall. An example of such a further embodiment includes a mill having rotating paddles which are used to move material within the mill and, while doing so, to mix and/or cut that material.

2018233052 24 Sep 2018 [0075] As mentioned above, knife 15 includes a mounting element. This element has, in addition to mounting plate 21, a substantially flat steel fixing plate 31 as best shown in Figure 3. Plate 31 is fixedly connected to plate 21 by way of welds (not shown). However, in other embodiments plates 21 and 31 are releasably secured to each other by bolts or other fastening devices. Plate 31 includes three equally spaced apart apertures 32 for complementarily receiving respective bolts (not shown) for allowing the removable securing of plate 31 to flighting 13 (or another milling piece).

[0076] In other embodiments, plate 31 is integrally formed with the milling piece. This arrangement is enabled in practice by blade 22 being replaceable without requiring the replacement of the knife as a whole.

[0077] In further embodiments, plate 31 is other than substantially flat to vertically incline blade 22 as it extends away from flighting 13. That is, blade 22 extends radially outwardly and either vertically upwardly or downwardly from flighting 13.

[0078] Plate 25 has substantially similar dimensions to and in use, directly overlies plate 21. Moreover, both plates 21 and 25 include a linear array of five overlying equally spaced apart apertures 33 that complementarily receive respective bolts for allowing the plates, in use, to clampingly engage and retain blade 22 in a first operative configuration as shown in Figure 3. (There is a second operative configuration for blade 22 that is described further below). More particularly, in the first operative configuration, blade 22 extends between a first end 35 and a second end 36 that is disposed, as illustrated in Figure 3, radially outwardly of end 35. Moreover, end 36 extends radially outwardly beyond plates 21 and 25 to stand proud of both. That is, in use, blade 22 is orientated such that one of the cutting edges - in this example, cutting edge 23 - is operatively exposed when blade 22 is secured to plate 21. Cutting edge 23 leads the progression of knife 15 during the rotation of auger 5 and substantially all of that cutting edge engages with the feedstock 3 being milled. It will also be appreciated that, in this first operative configuration, edge 24 of blade 22 is not operatively exposed and, hence will not be subject to significant wear and the associated blunting during the milling operation. It has been found that edge 24 is subject to minor wear adjacent to end 36. However, when blade 22 is reversed during maintenance to assume the second operative configuration, end 36 is disposed radially inwardly of end 35 and, as such, any minor wear to edge 24 will lie innermost where it has least impact upon the efficiency or effectiveness of the milling operation.

[0079] In other embodiments, end 36 is flush with the ends of plates 21 and 25. In further embodiments, end 36 is nested between plates 21 and 25.

2018233052 24 Sep 2018 [0080] As described above, blade 22 includes a plurality of substantially straight cutting edges - in this example, two opposite cutting edges 23 and 24 - where less than all of the cutting edges are operatively exposed when blade 22 is secured to the mounting element. Accordingly, while the use of the hardened edges on blades 22 extends the maintenance intervals, the provision of multiple edges (in this specific embodiment there are two edges) on blades 22 allows for alternate maintenance operations to be rapidly carried out as all that is required is for blades 22 to be reversed in the remainder of the knife such that the other of the available edges is operatively exposed for use in mill 1. That is, during alternate maintenance sessions there is no need to remove the knife as a whole, or to replace the knife as a whole, only to reverse the orientation of blade 22. This ability to quickly reorientate the blades from the first configuration to the second configuration assist to reduce downtime of mill 1.

[0081] In this embodiments, blade 22 is formed entirely of a metal, and in particular of a high speed steel (HSS) having a hardness of at least HRC 60. However, in other embodiments the hardness is at least HRC 58.

[0082] In other embodiments the metal is selected from the broader category of a tool steel. To achieve the desired levels of hardness, the tool steel, or the high speed steel, preferentially has a carbon content of between 0.5% and 1.5%.

[0083] While hardness itself is a useful quality for cutting edges and blades, the materials required to provide such hardness are often expensive to the point of being prohibitive in more general uses such as contemplated in the present embodiments. To address this issue the above embodiment makes use of a multi-component knife that allows the blade alone or the cutting edge alone to be made from HSS, a carbide, or other suitable material, while other components are of less expensive and/or more simply manufactured materials. In some embodiments substantially only the cutting edge of the blade is made or otherwise formed from the specialist material and other parts or portions of the blade are formed from less expensive materials. A specific example of this is provided by the carbide cutting edges being bonded or otherwise secured to a steel or other backing plate. This further reduces the amount of specialised and expensive material without compromising the operation of the blade, and while still allowing the benefits of the multiple piece knife to be realised.

[0084] This selective use of materials in the components of the knife, and the mounting of the knife, allows for more effective operation of mill 1, both in terms of the knives being able to cut rather than shear and by better containing downtime of the equipment during maintenance. It will also be appreciated that blades 22, once removed from plates 21, allow ease of sharpening of either or both of edges 23 and 24. This, in turn, allows the re2018233052 24 Sep 2018 use of blades 22 in mill 1 (or other mill), as distinct from the commonly used prior art solution of disposing of spent knives. Moreover, the sharpening of blades 22 (by reshaping edges 23 and 24) is able to occur while other like blades 22 are mounted to respective plates 21, allowing continued operation of mill 1. Moreover, the embodiments make use of generally straight blades with generally straight cutting edges which are both easier and less expensive to manufacture than curved blades. Moreover, the use of substantially straight cutting edges allows blade 22 to be more easily and consistently sharpened with a mechanised sharpener or with manual sharpening tools.

[0085] It will be appreciated that while the fitting and turning industry makes use of HSS and to some extent carbides, these materials are not readily directly available to the public. HSS are available for example, more typically, in a variety of HSS tools, such as metal drills. However, the use of HSS to form a knife is rare, and limited to very specialised cutting tasks where there is a very specific purpose in mind. It is usual for any such knife or cutting tool to be specifically manufactured by a specialist supplier of HSS tools and to have a very specific shape. This limited availability arises from the expense of the materials, both in terms of the manufacture of the material itself - which is hardened by heat treatment - and the subsequent processing required to form the given tool typically grinding and other treatments. This complexity and cost precludes HSS from most applications, and certainly from general use applications such as those contemplated by the present embodiments. However, the inventor has appreciated that by reconsidering the nature and structure of a knife in a stockfeed mill, and the mounting of the blade in the mill, it has become possible to gain the benefits of a cutting edge of HSS or a carbide without having to encounter the prohibitive costs of following the conventional wisdom of having the knife as a whole formed from the same material.

[0086] Another embodiment of a knife for use in a stockfeed mill is illustrated in Figures 4 and 5, where corresponding features are denoted with corresponding reference numerals. In particular, a knife 41 includes generally rectangular and integrally formed plates 21 and 31 that are releasably connected by bolts 42 (only one shown in Figure 5) to flighting 13. In this embodiment, apertures 32 are arranged in a linear array that extends parallel to blade 22 as distinct from the Figure 3 embodiment where the array extended normally to the blade. This allows mounting of integral plates 21 and 31 to be mounted to a milling piece such as an arm of a hammer mill. As in the earlier described embodiment, one of the cutting edges - edge 23 - leads the engagement of knife 41 with the material being milled such that cutting of the material occurs with that one edge.

2018233052 24 Sep 2018 [0087] In other embodiments bolts 42 are countersunk and/or have domed heads to lower the profile presented by knife 41 and to thereby reduce the risk of fouling with the material being milled.

[0088] Plate 21 includes a first substantially planar generally rectangular abutment face 45 and blade 22 includes a second substantially planar generally rectangular abutment face 46 which is in use opposed to, abutted with and which overlies face 45 when blade 22 is secured to plate 21. Face 45 terminates at a first outer bevelled face 47 and face 46 extends beyond face 47 and terminates in edge 23. That is, edge 23 defines a vertex of face 46 and an adjacent inclined face 48.

[0089] Plate 25 includes a third substantially planar generally rectangular abutment face 49 and blade 22 includes a fourth substantially planar generally rectangular abutment face 50 which is in use opposed to, abutted with, and which overlies face 49 when blade 22 is secured to plate 21. Face 49 terminates in a second bevelled face 51 that substantially aligns with face 47.

[0090] Plate 21 includes an elongate stop member, in the form of a fixedly attached steel stop 55 that, in use, extends between plates 21 and 25 and which abuts with plate 25. Stop 55 is fixedly secured to plate 21 by way of welds (not shown). In other embodiments different fixings are used. In further embodiments, stop 55 is fixedly secured to plate 25 and clampingly fixed during use to plate 21. In still further embodiments, stop 55 is integrally formed with one of plates 21 and 25, and in further embodiments again it is integrally formed with both.

[0091] The bevels defined by faces 47 and 51 recede away from edge 23 to aid the progression of knife 15 through the material being milled. In other embodiments, either or both of faces 47 and 51 are not bevelled but, rather, extend normal to faces 46 and 49 respectively.

[0092] A plurality of bolts 57 (only one shown in Figure 5) extend through apertures 33 and, together with the respective nuts, affect the clamping engagement of blade 22 to plate 21. In other embodiments bolts 57 are countersunk and/or have domed heads to lower the profile of knife 41 and reduce the risk of fouling with the material being milled.

[0093] Edge 24 of blade 22 is in part defined by an inclined face 59. As shown in Figure 5, with blade 22 orientated such that edge 23 is operatively exposed, face 59 and edge 24 remain substantially protected and both are disposed adjacent to the shank of bolts 57.

[0094] As shown in Figure 4, plate 21 also includes a second stop 60 that is spaced apart from and which extends normally to stop 55 for abutting with the innermost end of blade 22. In the configuration shown, the innermost end of blade 22 is end 35. However,

2018233052 24 Sep 2018 when the blade 22 is reversed into the second configuration to operatively expose edge 24, end 36 is abutted with stop 60. Stop 55 facilitates ease of alignment of blade 22 in knife 41.

[0095] In other embodiments face 45 of plate includes one or a plurality of indicia for designating operative positioning of respective blades. For example, where a plurality of blade sizes are available, the indicia provide locating information to allow the relevant personnel to place the blade of a given size and then tension bolts 57 to maintain that placing during operation of mill 1. In other embodiments where only one blade size is available, the indicia designate suggested operative positioning of the blade for milling different materials. In further embodiments the indicia do both.

[0096] In other embodiments the indicia are formations in face 45. Examples of such formations include ridges, indentations, whether machined, painted or otherwise marked.

[0097] It will be appreciated that stop 60 and any locating indicia or formations allows for ease of placement and alignment of blade 22 during maintenance. The relevant operator simply loosens the nuts tensioning bolts 57 to allow removal of blade 22 from between plates 21 and 25. The blade is reorientated such that end 36 is placed where end 35 is shown in Figure 4, such that edge 24 is operatively exposed. Then the nuts are tightened to re-tension bolts 57 to clamplingly engage blade 22 in the new orientation. Alternatively, if both edges 23 and 24 are dull, then rather than reorientating the removed blade 22, that blade is retained for sharpening or other rehabilitation and/or repair, and a sharpened like knife is placed on face 45 and aligned and orientated in the same way so that one of the edges of that blade is operatively exposed.

[0098] In some embodiments blade 22 includes a distinctly coloured sacrificial coating, at least adjacent to ends 35 and 36. During use this coating will be abraded to indicate which end of blade 22 has been disposed outermost in knife 15. Accordingly, when blade 22 is removed it will be clearly evident to the service personnel if both edges of knife 22 have been operatively exposed, or not.

[0099] Edges 23 and 24 have a linear profile due to the nature of the milling process and the need to only sharpen this profile from one side. In other embodiments different profiles are used such as a chisel profile or a wedge profile. It will be appreciated by those skilled in the art that other profiles are also available.

[00100] In other embodiments alternative blades are used with only a single edge. For example, in Figure 6(a) there is illustrated the profile of a blade 63 that has a single edge 64 with a linear profile. The blade includes a flat face 65 that, in use, rests against the shanks of bolts 57. A further example is provided in Figure 6(b), where a blade 67 has

2018233052 24 Sep 2018 a single edge 68 with a wedge profile. The blade includes a flat face 69 that, in use, rests against the shanks of bolts 57.

[00101] In further embodiments of the invention use is made of blades having carbide edges. An example of such a blade 71 is illustrated in Figure 9. In particular, blade 71 includes two opposite cutting edges 72 and 73 that are both formed from tungsten carbide which is bonded to opposite sides of a steel backing plate 74. Blade 71 includes like dimensions to blade 22. In other embodiments blade 71 has different dimensions to blade 22. Moreover, in some embodiments blade 71 is formed from other carbides, such as boron carbide or silicon carbide.

[00102] A further blade 75 making use of tungsten carbide is illustrated in Figure 10. More particularly, blade 75 includes a single cutting edge 76 that is bonded to a backing plate 77. This blade 75 has similar dimensions to the blade of Figure 6(b).

[00103] Reference is now made to Figure 7, where corresponding features are denoted by corresponding reference numerals. As illustrated, a knife 81 includes an integrally formed plate 82 and stop 83 rather than the separate plate 25 and stop 55 of the Figure 5 embodiment.

[00104] Reference is now made to Figure 8, where corresponding features are denoted by corresponding reference numerals. As illustrated, a knife 91 includes an integrally formed plate 92, plate 93 and stop 94 rather than the separate plate 21, plate 25 and stop 55 of the Figure 5 embodiment. Plate 93 include a plurality of spaced apart grub screws 95 (only one shown) that are complementarily received in respective threaded apertures 96 (only one shown) for releasably clamplingly engaging with blade 22.

[00105] In the Figure 2 embodiment knives 15 extend directly radially outwardly from flighting 13. This is schematically represented in Figure 11, where corresponding features are denoted by corresponding reference numerals. As shown, axle 11 rotates counter clockwise (indicated by arrow 101) such that blades 22 are disposed normal to this direction of travel. This is referred to as a high angle of approach or a high angle of attack for blade 22 as it directly cuttingly engages with the material to be milled rather than attempting to shear the material. This high angle of attack results in more cutting action per revolution of auger 5, provided there is sufficient power to run mill 1 and that mill 1 is not overloaded. As blades 22 remain sharp for longer periods this ability to use high angles of approach contribute significantly to the effective operation of mill 1.

[00106] In other embodiments a lower angle of approach (or angle of attack) is used, such as that illustrated by blade 102. In further embodiments even lower angles of attack are used, such as that represented by blade 103. These lower angles of attack are used in the embodiments of the invention to deal with larger pieces of material to be milled. For

2018233052 24 Sep 2018 example, in some embodiments the knives closest to opening 4 have a lower angle of attack to facilitate entry of the larger pieces into bin 2, whereas the knives disposed closer to outlet 7 have a higher angle of attack. This allows the use of a single blade size in all the knives while providing progressively more cutting of the material to be milled as it moves through bin 2.

[00107] A number of prior art knives utilise a low angle of attack in an attempt to gain adequate operational lifetime for the knife by allowing a slicing/shearing action on the material. While the knives of the embodiments of the invention do not require such low angles of attack to achieve improved operation lifetimes, they can still be used in such a configuration to provide other functionalities and to gain other advantages.

[00108] It will be appreciated, given the benefit of the above teaching, that the preferred embodiments provide a method for securing blade 22 to a flighting 13. This includes the steps of:

providing a plate 21 that extends from flighting 13;

removably mounting blade 22 to plate 21, where the blade has a cutting edge, edge 23, that is formed from a metal or a carbide with a hardness of at least HRC 55; and releasably securing blade 22 to plate 21 with plate 25 to expose edge 23.

[00109] Additionally, the preferred embodiments provide a method of milling stockfeed including the steps of:

providing a bin 2 for receiving stockfeed 3 to be milled;

disposing auger 5, including flighting 13, in bin 2 for milling stockfeed 3;

providing an outlet 7 for directing milled stockfeed 8 from bin 2;

providing a drive train (in the form of shaft 9 and transmission 10) for allowing drive to be transferred to auger 5;

providing a plurality of spaced apart plates 21 that extend from flighting 13; removably mounting a plurality of blades 22 to respective plates 21, each blade having a cutting edge 23 formed from a metal or a carbide with a hardness of at least HRC 55; and releasably securing blades 22 to respective plates 21 with corresponding plates 25 to expose edges 23.

[00110] Additionally, the preferred embodiments provide a method for securing blade 22 to flighting 13, where the method including the steps of:

providing plate 21 that extends from flighting 13;

removably mounting blade 22 to plate 21; and releasably securing blade 22 to plate 21 with plate 25.

2018233052 24 Sep 2018 [00111] The main advantages of the embodiments described above include:

• A knife with a removeably mounted blade, rather than the prior art solution of a removeably mounted knife. This allows for the replacement of the blade only, the remainder of the knife only, or the knife as a whole.

• The use of a hard cutting edge, without having to have all of the knife constructed from such material.

• High speed steel blades offer high abrasion resistance which is advantageous in milling fibrous materials such as those being considered.

• Carbide tipped blades offer high abrasion resistance which is advantageous in milling fibrous materials such as those being considered.

• Higher angles of attack for the blade, which in turns increases the cutting action.

• The use of a hard steel for the cutting edge to allow for a more effective cutting action during the milling process while also offering a longer service interval.

• Sharpening of cutting edges is able to be performed on removed blades without having to remove the knife as a whole.

• Cutting edges can be made straight which simplifies the sharpening of blades.

• Increases the longevity of all the components of the knife by allowing the cutting edge to be designed primarily to perform cutting, and the mounting formations to be designed primarily to perform a mounting. The prior art solutions were for a single component to perform both.

• The blade is able to have multiple cutting edges, which allows for a minor service interval where the orientations of the blades are changed to operatively expose an as yet unused and sharpened edge rather than having to replace the knife as a whole.

• The stockfeed is able to be produced with less power as more effective cutting, rather than shredding, is provided.

• The cutting also reduces the production of fines (dust).

2018233052 24 Sep 2018 • The effective cutting of the feedstock reduces wear to the mill and, due to lower power requirements, on the tractor or other machinery that provides drive to the mill.

• Effective cutting of the feedstock decreases the stress loading within the machine.

• Allow for much improved maintenance of the blades. In particular, the installation of a special purpose cutting edge is straightforward.

• Regular sharpening of blades is far more practical as the blades are easily removed from the mill (and substituted with sharpened blades) to make the operation of the mill independent of the sharpening of the blades.

• Allows for marking or locating formations to be provided with the knife to facilitate accurate and easily reproducible blade placement.

• Allows for a single blade to be fitted to all knives (to reduce inventory requirements for the operator of mill 1).

• A large contact area between the blade and the opposed plates ensure the blade is well retained to the knife during the milling process. It also ensures that the blade is well supported as some HSS, carbides and other blade materials are brittle.

[00112] It will be appreciated that the disclosure above provides various significant improvements in a knife for a stockfeed mill and a stockfeed mill including such a knife.

[00113] It should be appreciated that in the above description of exemplary embodiments of the invention, various features of the invention are sometimes grouped together in a single embodiment, Figure, or description thereof for the purpose of streamlining the disclosure and aiding in the understanding of one or more of the various inventive aspects. This method of disclosure, however, is not to be interpreted as reflecting an intention that the claimed invention requires more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive aspects lie in less than all features of a single foregoing disclosed embodiment. Thus, the claims following the Detailed Description are hereby expressly incorporated into this Detailed Description, with each claim standing on its own as a separate embodiment of this invention.

[00114] Furthermore, while some embodiments described herein include some but not other features included in other embodiments, combinations of features of different embodiments are meant to be within the scope of the invention, and form different

2018233052 24 Sep 2018 embodiments, as would be understood by those skilled in the art. For example, in the following claims, any of the claimed embodiments can be used in any combination.

[00115] In the description provided herein, numerous specific details are set forth. However, it is understood that embodiments of the invention may be practiced without these specific details. In other instances, well-known methods, structures and techniques have not been shown in detail in order not to obscure an understanding of this description. [00116] Similarly, it is to be noticed that the term “coupled” or “connected”, when used in the description and claims, should not be interpreted as being limited to direct connections only. The terms coupled and connected, along with their derivatives, may be used. It should be understood that these terms are not intended as synonyms for each other. Thus, the scope of the expression “a device A coupled to a device B” should not be limited to devices or systems wherein an output of device A is directly connected to an input of device B. Rather, it means that there exists a path between an output of A and an input of B which may be a path including other devices or means. Coupled may mean that two or more elements are either in direct physical or electrical contact, or that two or more elements are not in direct contact with each other but yet still co-operate or interact with each other.

[00117] Thus, while there has been described what are believed to be the preferred embodiments of the invention, those skilled in the art will recognize that other and further modifications may be made thereto without departing from the spirit of the invention, and it is intended to claim all such changes and modifications as falling within the scope of the invention. For example, any formulas or flowcharts provided are merely representative of procedures that may be used. Functionality may be added or deleted from the block diagrams and operations may be interchanged among functional blocks. Steps may be added or deleted to methods described within the scope of the present invention.

Claims (50)

1. A knife for a stockfeed mill having a milling piece, the knife including:

a mounting element for extending from the piece;

a blade for removably mounting to the mounting element, the blade having a cutting edge with a hardness of at least HRC 55; and a fastening element for releasably securing the blade to the mounting element to expose the cutting edge.

2. A knife according to claim 1 wherein the cutting edge is formed from a carbide.

3. A knife according to claim 1 wherein the cutting edge is formed from a metal.

4. A knife according to any one of the preceding claims wherein the cutting edge has a hardness of at least HRC 58.

5. A knife according to any one of the preceding claims wherein the cutting edge has a hardness of at least HRC 60.

6. A knife according to claim 3 wherein the metal is a tool steel.

7. A knife according to claim 6 wherein the tool steel has a carbon content between 0.5% and 1.5%.

8. A knife according to any one of claims 3, 6 and 7 wherein the metal is a high speed steel.

9. A knife according to any one of the preceding claims wherein the blade includes a plurality of cutting edges and less than all of the cutting edges are simultaneously operatively exposed when the blade is secured to the mounting element.

10. A knife according to any one of the preceding claims wherein the milling piece, in use, is movable in the mill.

11. A knife according to any one of claims 1 to 8 wherein the milling piece, in use, is fixed in the mill.

12. A knife according to claim 11 wherein the mill includes a receptacle for receiving stockfeed to be milled, the receptacle being defined at least in part by a sidewall that defines the milling piece.

13. A knife according to claim 11 or claim 12 wherein the mill includes a further milling piece and, in use, the milling pieces move relative to each other.

14. A knife according to claim 13 wherein the further milling piece is an auger.

15. A knife according to any one of claims 1 to 12 wherein the mounting element is releasably secured to the milling piece.

16. A stockfeed mill having a milling piece from which extends one or more of the knives of any one of the preceding claims.

2018233052 24 Sep 2018

17. A stockfeed mill according to claim 14 having a plurality of milling pieces each having at least one of the knives of any one of claims 1 to 15.

18. A stockfeed mill according to claim 17 wherein at least two of the milling pieces, in use, move relative to each other.

19. A method for securing a blade to a milling piece for a stockfeed mill, the method including the steps of:

providing a mounting element that extends from the piece;

removably mounting a blade to the mounting element, the blade having a cutting edge with a hardness of at least HRC 55; and releasably securing the blade to the mounting element with a fastening element to expose the cutting edge.

20. A stockfeed mill having:

a receptacle for receiving stockfeed to be milled;

at least one milling piece disposed within the receptacle for milling the stockfeed; an outlet for directing the stockfeed from the milling piece;

a drive train for allowing drive to be transferred to the piece;

a plurality of spaced apart mounting elements that extend from the piece;

a plurality of blades for removably mounting to the respective mounting elements, each blade having a cutting edge with a hardness of at least HRC 55; and a fastening element for releasably securing the blades to the respective mounting elements to expose the cutting edges.

21. A stockfeed mill according to claim 20 wherein the fastening element includes a plurality of spaced apart fastening elements for engaging with respective blades.

22. A stockfeed mill according to claim 20 or claim 21 wherein the mounting elements are releasably mounted to the piece.

23. A stockfeed mill according to claim 22 wherein the mounting elements are individually releasably mounted to the piece.

24. A stockfeed mill according to any one of claims 20 to 21 wherein the receptacle is defined at least in part by a sidewall and that sidewalls defines the piece.

25. A method of milling stockfeed including the steps of:

providing a receptacle for receiving the stockfeed to be milled;

disposing a milling piece within the receptacle for milling the stockfeed;

providing an outlet for directing the stockfeed from the milling piece;

providing a drive train for allowing drive to be transferred to the piece;

providing a plurality of spaced apart mounting elements that extend from the piece;

2018233052 24 Sep 2018 removably mounting a plurality of blades to the respective mounting elements, each blade having a cutting edge with a hardness of at least HRC 55; and releasably securing the blades to the respective mounting elements with a fastening element to expose the cutting edges.

26. A method according to claim 25 where the step of securing the blades includes individually releasably securing the blades.

27. A knife for a stockfeed mill having a milling piece, the knife including:

a mounting element for extending from the piece;

a blade for removably mounting to the mounting element; and a fastening element for releasably securing the blade to the mounting element.

28. A knife according to claim 27 wherein the fastening element clamplingly secures the blade to the mounting element.

29. A knife according to claim 27 or claim 28 wherein the mounting element is integrally formed with the piece.

30. A knife according to any one of claims 27 to 29 wherein the mounting element is removably secured to the piece.

31. A knife according to any one of claims 27 to 30 wherein the mounting element includes a first abutment face and the blade includes a second abutment face that is abutted with the first abutment face when the blade is secured to the mounting element.

32. A knife according to claim 31 wherein the first abutment face terminates at a first outer edge and the second abutment face extends beyond the first outer edge.

33. A knife according to claim 31 or claim 32 wherein the fastening element includes a third abutment face and the blade includes a fourth abutment face that is abutted with the third abutment face when the blade is secured to the mounting element.

34. A knife according to claim 33 wherein the third abutment face terminates in a second outer edge that substantially aligns with the first outer edge.

35. A knife according to any one of claims 27 to 34 wherein the mounting element includes a stop member that, in use, extends between the mounting element and the fastening element.

36. A knife according to claim 35 wherein the stop member is fixedly secured to at least one of: the mounting element and the fastening element.

37. A knife according to claim 36 wherein the stop member is integrally formed with at least one of: the mounting element and the fastening element.

38. A knife according to claim 36 or claim 37 wherein the stop member is fixedly secured to both of the mounting element and the fastening element.

2018233052 24 Sep 2018

39. A knife according to claim 27 wherein the mounting element and the fastening element are integrally formed.

40. A knife according to claim 27 or claim 39 wherein the fastening element releasably clampingly secures the blade to the mounting element.

41. A knife according to claim 27 or claim 39 wherein the fastening element releasably secures the blade to the mounting element in an interference fit.

42. A knife according to any one of claims 27 to 41 wherein the blade includes a cutting edge that is exposed when the blade is secured to the mounting element.

43. A knife according to any one of claims 27 to 42 wherein the cutting blade includes a plurality of cutting edges and less than all of the cutting edges are operatively exposed when the blade is secured to the mounting element.

44. A knife according to any one of claims 27 to 43 wherein the cutting blade includes two cutting edges, one of which is operatively exposed when the blade is secured to the mounting element.

45. A method for securing a blade to a milling piece of a stockfeed mill, the method including the steps of:

providing a mounting element that extends from the piece;

removably mounting the blade to the mounting element; and releasably securing the blade to the mounting element with a fastening element.

46. A method according to claim 45 wherein the blade includes a cutting edge and the method includes the prior step of forming the cutting edge from a tool steel or a carbide.

47. A method according to claim 45 wherein the prior step includes selecting the metal or carbide having a hardness of at least HRC 55.

48. A method according to claim 45 wherein the metal is a tool steel.

49. A method according to claim 48 wherein the metal is a high speed steel.

50. A method according to claim 45 wherein the blade is substantially wholly formed from the high speed steel.