NZ573496A - Stump grinder head - Google Patents

Abstract

Disclosed is an apparatus for supporting at least one cutter tooth. The cutter tooth support apparatus is adapted in use for removable attachment to a rotatable grinder plate having side surfaces and an edge perimeter. The body of the apparatus has at least one slot or pocket with an entrance, the slot is shaped and adapted when in use to hold at least one tooth.

Description

Patents Form # 5 NEW ZEALAND Patents Act 1953 COMPLETE SPECIFICATION AFTER PROVISIONAL NO.: 573496 PRIORITY DATE : 09 December 2008 TITLE : Stump grinder head I, CROXTON, David James Address: 106 Hutchinsons Road, Ho wick, Auckland, New Zealand, 2014 Nationality: A citizen of New Zealand do hereby declare the invention for which I pray that a patent may be granted to me and the method by which it is to be performed, to be particularly described in and by the following statement: . 1 - 192009NZ_Cap_20100308_1503_EHB.doc FEE CODE 1050 Recieved At IPONZ 30 June 2011 2 Stump grinder head The invention relates to a grinder tooth support apparatus. The invention is directed particularly but not solely towards a stump grinder head having several cutting teeth, for tree stump grinder machines.

Background of Invention Normally stump grinder machines are known to be portable machines that are used to remove tree stumps in the ground. These types of machines are generally petrol or diesel driven which can be operated by a single operator. These machines can be very heavy and require training to operate efficiently and safely.

The actual cutting part of the grinder machines is arranged on a housing which includes a rotating head having at least one cutter tooth mounted thereon. In general one can refer to a single tooth or more than one tooth as 'teeth' throughout the specification, though the term 'tooth' or 'teeth' is merely a convenient term to describe a slender elongate cutting member. The mounting of the cutter teeth relies on an exposed tooth or teeth to do the cutting or grinding, which is not a very robust mounting, causing cutter teeth to regularly break or snap. Any such breakages are costly to the operator and cause significant delays. Extending the working life of the cutter teeth makes the machine more profitable to operate.

The layout and mounting of the cutter teeth also causes other parts of the grinder machine to need replacing which also contributes to down time and parts replacement costs. Current mounting of the cutter teeth to a central plate or disc, also do not provide the best cutting performance meaning that extra effort by the operator has to be put in to achieve a good stump grind. Also current machines have a limited number and positioning of two teeth on a solid plate having slots or no slots whereby only straight teeth may be used in a plate slot.

With the current layout having more exposed cutter teeth there is a greater risk of injury and damage due to hidden objects being thrown out. Also current small machines tend to be too light to allow good use of engine torque. Plunge cutting as is known in the industry can be faster and requires less operator effort than other forms of cutting. Most cutting machines G:¥192009NZ AMND SPEC 29JUNE2011 EHB.DOC Recieved at IPONZ on 27 July 2011 3 cannot plunge cut but can only cut in very small cutting sweeps which takes much longer. This type of problem is particularly relevant to the walk behind style of machine.

In this specification unless the contrary is expressly stated, where a document, act or item of knowledge is referred to or discussed, this reference or discussion is not an admission that the document, act or item of knowledge or any combination thereof was at the priority date, publicly available, known to the public, part of common general knowledge; or known to be relevant to an attempt to solve any problem with which this specification is concerned.

Object of the Invention It is an object of the invention to provide a grinder cutter tooth support apparatus or stump grinder machine that ameliorates some of the disadvantages and limitations of the known art or at least provide the public with a useful choice.

Summary of Invention In a first aspect the invention resides in a grinder cutter tooth support apparatus for supporting at least one cutter tooth being elongate with faces, the cutter tooth support apparatus being adapted in use for removable attachment to a rotatable grinder plate having side surfaces and an edge perimeter, of a grinder head assembly, having a rotating mass the cutter tooth support apparatus including a shaped member body, the body comprising at least one slot or pocket therein having an entrance, the slot is shaped and adapted when in use to hold at least one tooth therein, in use the body has an upper outer body surface to face away from the grinder plate and a lower outer body surface to face and abut the grinder plate, whereby side edge faces separate the upper and lower outer body surfaces, when one body is fitted to one side of the plate with lower outer body surface abutting one surface of the plate, the slot is located within the lower outer surface of the body to have its opening located in one of the body side edge faces, to allow at least one cutter tooth to be able to be fitted into the slot, to have a protruding portion beyond the slot entrance and one body side edge face so that one edge face of the said at least one cutter tooth is a cutting surface at a front and the said at least one cutter tooth having a rear surface wherein when in use the said one side edge face of the rotatable plate is oriented with respect to the body such that the one body side edge has a trailing edge portion to the rear of the said at least one cutter tooth whereby the body side edge has a protruding portion in the trailing edge portion to support all of the rear G:¥192009NZ AMND SPEC 27July2011 EHB.DOC Recieved at IPONZ on 27 July 2011 4 of the protruding said at least one cutter tooth portion and to enable the said at least one cutter tooth to protrude non-radially from the rotatable plate to allow only the cutting surface of the said at least one cutter tooth to protrude and to cut or grind when in use whereby all of the rear and front of said at least one cutter tooth is fully supported the body except for the cutting surface only.

Preferably the said cutter tooth has an elongate shaped body with a cutting portion at one end whereby the said at least one cutter tooth is protected and supported up to its cutting portion.

Preferably the plate has a curved plate edge perimeter and the body side edge can be curved to follow the curved plate edge whereby when the body having at least one cutter tooth, is fitted to the plate by body fixing means, said at least one cutter tooth is positioned to protrude from the plate edge and body side edges face, to cut when required in use.

Preferably, one of the other body side edge faces is shaped having a leading protruding portion that functions to shade the body outer surface to protect the body fixing means from wear.

Preferably, the protruding portion of the curved body edge has a grooved portion which is located immediately adjacent and in use above a ledge, whereby the grooved portion functions to allow a clear view of the side of the said at least one cutter tooth.

Preferably the body is sized and shaped by having an outer contoured face with a raised ridge for durability and weight to increase the rotating mass of the grinder head assembly.

In a second aspect the invention resides in a grinder head assembly, the assembly includes a teeth support apparatus for removable attachment by fastening apparatus to both sides of a grinder plate having an edge perimeter, a grinder plate and cutter teeth, each block shaped member body comprising a slot therein, shaped and adapted to hold at least one tooth therein, in use the block has an outer upper surface to face away from the grinder plate and opposite the outer surface, a lower outer surface to face the grinder plate and side edge faces when the body is fitted to the plate, the slot is located in the lower surface to exit from one of the side edge faces, to allow at least one fitted cutter tooth to protrude beyond one block side G:¥192009NZ AMND SPEC 27July2011 EHB.DOC Recieved At IPONZ 30 June 2011 surface to exit from one of the side edge faces, to allow at least one fitted cutter tooth to protrude beyond one body side edge face wherein when in use the said one side edge face is oriented such that the one body side edge has a trailing edge portion behind the at least one cutter tooth whereby the body has a protruding portion in the trailing edge face to support the rear of the at least one cutter tooth to enable the at least one cutter tooth to protrude non-radially from the rotatable plate to allow only the cutting surface of the at least one cutter tooth to protrude to cut or grind when in use, whereby all of the rear and front of each at least one cutter tooth is fully supported the body except for the cutting surface only.

Preferably, the plate has slots circumferentially arranged there in to be aligned with the body slots to allow three cutter teeth to be arranged (between two mounting blocks) therein.

Preferably, the assembly includes a spacer member which can be located under each body to space the body further from the plate.

Preferably, the body can be located on the plate in a position relative to the plate edge whereby the side edge is either flush or is level there-with.

Preferably, one of the body sides is shaped having a leading edge that shades the body outer surface to protect body fixing means.

Preferably, the protruding portion includes a grooved portion is immediately adjacent a ledge which functions to allow a clear view of the side of the cutter tooth.

In a third aspect the invention resides in a grinder head assembly, the assembly including the grinder cutter tooth support apparatus for supporting the said at least one cutter tooth as disclosed previously, on each side of a rotatable grinder plate wherein the plate has a slot therein and each support apparatus has a slot whereby several configurations of the said at least one cutter tooth placement in the slots are provided to give a maximum of three teeth therein to cut and grind as required as a full width continuous cut from tooth to tooth when the plate is rotated.

G:¥192009NZ AMND SPEC 29JUNE2011 EHB.DOC Recieved At IPONZ 30 June 2011 6 Brief Description The invention will now be described, by way of example only, by reference to the accompanying drawings: Figure 1 is a side view of the grinder cutter teeth support assembly in accordance with a first preferred embodiment of the invention.

Figure 2 is a schematic perspective close up view of one cutter tooth support means/block.

Figures 3a-3d are schematic views of the two main types of cutter teeth ie Straight teeth and angle teeth, both left and right.

Figure 4 is a schematic representation of tooth or teeth layouts in a single overlapped view.

Figures 5a-5e show further schematic representations of tooth or teeth positions.

Figure 6 is schematic perspective view of the underneath of a block with the slot being shown to be extending the whole radial width of the block.

Figures 7-12 show various tooth layouts which are possible.

To those skilled in the art to which the invention relates, many changes in construction and widely differing embodiments and application of the invention will suggest themselves without departing from the scope of the invention as defined in the appended claims. The disclosures and the descriptions herein are purely illustrative and are not intended to be limiting.

Description of Drawings The following description will describe the invention in relation to preferred embodiments of the invention, namely a grinder tooth support assembly as shown in figures 1-12. The invention is in no way limited to these preferred embodiments as they are purely to exemplify the invention only and that possible variations and modifications would be readily apparent without departing from the scope of the invention.

Throughout the specification terms like 'trailing' or 'leading' or 'front' and 'rear' are used in G:¥192009NZ AMND SPEC 29JUNE2011 EHB.DOC Recieved At IPONZ 30 June 2011 7 reference to when the invention is being used to cut or grind.

In figure 1 a grinder tooth support assembly 1 is shown which comprises a grinder disc or plate member 2 which removably supports at least one tool in the form of tooth or teeth support means 3 and at least one tooth or teeth 4. In use as part of a tree stump grinder machine M (as partly shown in figures 7-12) the grinder plate 2 is rotationally supported and moved about its centre C (see figure 1). As shown for example there are six teeth support means 3 spaced circumferentially on one side 5 of the plate 2 but as shown in figure 2 there are another matching set of teeth support means 3 on the other face (or underneath as shown in figure 2) of the plate 2. Each set of teeth support means 3 on each side are aligned together to form pairs which are removably connected and fixed together with the plate 2 sandwiched in between. Each tooth support means 3 has at least one slot or pocket 26 to removably house the tooth or teeth 4 therein. In use the block slot 6 faces towards the plate 2 to then close off each block slot 26.

Plate 2 is round or circular in shape and has a thickness 7 with a peripheral edge face 8.

Slots 9 are cut into both sides of the plate 2 which can be called plate slots 9 but having an alternating sequence by being on one side and then the other but in alignment as pairs with the plate clamped in between. Plate 2 also has a central rotating aperture 10 surrounded smaller apertures 11 being within a reduced thickness section of the plate 2. Also located on and through the plate thickness 7 are further spaced apertures 12 which are positioned close to the periphery of the plate 2. Central apertures 11 (which are spaced outwardly from the central rotating aperture 10) are provided to enable fixing to a rotating shaft (not shown) and outer apertures 12 are for enabling wedges (not shown) to be inserted there through to provide a safety stop when required such as for example when repairing the grinding machine or replacing teeth.

The tooth support means 3 can be termed a "block" 3. The term 'tooth' and 'teeth' are meant to relate to their number with any discussion in referring to a 'tooth' can also refer to 'teeth' as well. Together, the tooth support means 3 which is in the form of a block shaped body, on both sides of the plate 2 (a pair of blocks 3 plus the plate 2) form separate pockets 15 for the teeth 4 to be adjustably located. From this point on for ease of use we can refer the 'tooth support means' 3 to being 'block' 3.

G:¥192009NZ AMND SPEC 29JUNE2011 EHB.DOC Recieved At IPONZ 30 June 2011 8 Each block 3 has block fixing apertures 16 there-through (the flat face) one block 3 through the abutting centrally located plate member 2 and then through the other abutting aligned tooth support means or block 3 as located on the other side face 5 of plate 2 to allowing proper fastening a grinder head assembly. Fastening means which for example can be by round head shaped bolts (Cap screws) 17 inserted through the aperture 16 to bolt the tooth support means to the plate 2 by a hexagonal nut pocketed into the block or threads tapped into the block. Each block 3 comprise a semi-flat or low profiled block of contoured solid steel including in use a contoured outer face 18 bounded by side edges and an inner planar face for use in abutting the plate 2.

Each solid steel block 3 in plan view includes a substantially non-circular shape though other shapes are equally possible. Outer contoured face or upper outer surface 18 has a raised ridge edge L shaped plan portion 19 and with the rest of face 18 being a recessed planar portion 20 for locating the fixing apertures 16 and bolts to be located. Fixing apertures 16 each have a recessed edge portion 21 to allow each bolt head to be recessed from upper outer surface 18 of the block 3 so that during use, the bolt heads will be subject to reduced wear during rotation/grinding.

Block 3 also has a lower(when in use) outer surface 25 which is separated from the upper outer surface 18 by the side edge faces. The lower outer surface 25 (ie facing the plate 2) of the block 3 includes a block slot 26 having a narrow inner portion (not shown) leading out to a flared entrance portion 27. Block slot 26 is shaped and configured to allow at least one tooth 4 therein to be inserted and located therein and then protrude beyond the plate edge 8 and/or the block upper outer surface 18. Block slot 26 is shaped having three side walls with walls 27 being planar and parallel to each other and the bottom wall 28 is planar or curved, the block slot 26 being generally shaped as a downwardly (with respect to the plate) facing open trench which can extend as far across the block 3 as is necessary but which such slot 26 is covered by the plate outer surface.

Each block slot 26 has a depth or thickness 29a at right angles to its length somewhat less than the comparable depth or thickness 29b of each tooth 4 so that in use the tooth thickness protrudes from the block slot 26 when in place, whereby clamping or fastening each block 3 G:¥192009NZ AMND SPEC 29JUNE2011 EHB.DOC Recieved At IPONZ 30 June 2011 9 to the plate 2 will cause the teeth 4 to be abuttingly held in place. This is shown in figure 5a-e. Each block slot can accommodate one tooth and a plate slot can accommodate one tooth but where the plate slot 9 is abutting a block on each side of the plate, up to three tooth can be accommodated to then protrude from the block slot to allow clamping of an outer tooth face directly to a face of the plate.

As shown in figure 4(a-d) each tooth 4 comprises an elongate solid member formed from steel which normally comes in two shapes 4a & 4b, 4c & 4d. One tooth shape can be termed a substantially straight tooth 30 (see figures 3 a & b)and the other tooth shapes are non straight teeth (see figures 3 c&d) such as bent teeth 31 having a square cross section with four faces to match or complement the slot 26 to allow sliding therein and having a length 34. Each tooth 4 has an elongate body with a stem portion 32 leading to a cutting portion 33. The cutting portion 33 comprises a tungsten flat plate portion 35 being oriented and joined onto at least one tooth face in an inclined position with respect to that at least one tooth face and still being oriented somewhat parallel to the length 34 of the tooth 4. The flat portion 35 has a distal end 36 almost matching the distal end 37 of each stem portion 32 and extending down the stem portion 32 to finish in a ledge 37a being generally at right angles to the length 34 of a tooth 4. The extent of the flat portion down the stem portion 32 is significantly less than the entire length of each tooth.

In use one plate 2 on each face 5 removably supports several blocks 3 such as for example in figure 1 there are blocks 3 evenly circumferentially spaced 38 affixed thereto on each side of the plate 2. The block spacing 38 can be determined as being that distance that allows fastening between plate apertures 16 and which allows them to be fitted relatively easily and reduces any clogging with grinding debris. As the outer lower surface 25 of each block 3 abuts an outer plate surface 5, the open trench of the block slot 26 is then covered forming a four sided slot for at least one tooth 4.

In this type of situation where the block slot 26 is abutted by the plate then only one tooth 4 is able to be fitted there in and clamped by each block 3 to the plate 2. However in the situation where the plate 2 and block 3 is located by aligning block slot 26 with the plate slot 9, there is then room to put two teeth 4 therein plus another therein which abut each other.

G:¥192009NZ AMND SPEC 29JUNE2011 EHB.DOC Recieved At IPONZ 30 June 2011 This means that one extra tooth 4 can be aligned with the plate thickness 7. Even without the plate slot 9, block slots 26 for each block 3 on each side of the plate 2 are aligned together. The teeth 4 are placed in the slots 9 and 26 whereby the cutting face 33 lies in a semi-radial position to cut when the plate 2 is rotationally driven.

In another option (see figure 5(e)) a spacer plate 39 can be placed between the outer lower surface 25 of a block 3 and the outer plate face surface 5. This spaces the block(s) 3 out from the plate 2 outer plate face surface 5 thereby placing the cutting teeth 4 further out to enlarge the cutting plunge width (as defined by being how wide the grinder can plunge grind) and reducing drag and wear on non-spaced blocks 3.

Each block 3 as seen in figure 5(e) has the outer or outer upper surface 18 and outer lower face 25 bordered by side edges formed by four edge faces or planes being at an angle thereto. These edge face planes comprise a substantially flat face 40 being at right angles to the plate outer upper surface 18 and also being oriented generally radial with respect to the plate centre 6 and perpendicular to the peripheral plate edge 8. This side face 40 can also be contoured somewhat or can be stepped at a lower end if necessary for balancing the blocks 3 and teeth 4 on the plate 2.

Second and third edge faces include edge faces 41 & 42 which are also substantially planar and at right angles to the plate surface 5 but are joined by a curved portion together as seen in figure 2. One of these edge faces 41 & 42 can have a stepped portion which joins the stepped portion of edge face 40. Edge faces 41 & 42 form the edge planes which are located perpendicularly onto the plate outer surface 5.

The fourth edge face is a curved cutting edge face 43 of each block which essentially is a cutting edge face whereby teeth when fitted to the block (the block being fitted to the plate of a grinder head assembly) can cut or grind. Curved cutting edge 43 which when fitted to a plate 2, is substantially parallel to the curved peripheral plate edge 8 of the plate 2. Block edge face 40 is termed the leading edge when the plate 2 is rotating and edge plane 41 is termed the trailing edge and the teeth 4 are positioned almost radially (which can be varied to affect the grinding or cutting) with cutting face 33 being the most forward.

G:¥192009NZ AMND SPEC 29JUNE2011 EHB.DOC Recieved At IPONZ 30 June 2011 11 Curved cutting edge face 43 should not interfere with the rotating plate 2 and the teeth 4 but yet allow all the protruding teeth 4 to cut as required. Curved edge face 43 has a length 50 comprising a leading portion 51 and trailing portion 52 being defined with respect to the position before or after each tooth 4.

"Leading portion" can be defined as being in the direction of R while trailing is in the opposite direction which means that the cutting face 33 faces the leading portion while the ledge 53a is located in the trailing portion of the block when it is being rotated. This means that the tooth 4 defines a border between the leading and trailing portions and there can be a rear or front of each tooth. The front face of each tooth is face 35 ie facing the leading portion and the rear can be defined as anywhere behind that face 35 including the trailing portion, though the position of the border can be either located at the rear of the tooth .

Curved edge face 43 includes an upper portion 53 and lower portion 54 (with respect to the plate 2) with the block slot 26 being located approximately a third of plane length 50 from the trailing end edge of curved edge face 43. Block slot 26 is generally oriented in a radial direction in the block 3.

Leading portion 51 of the curved edge face 43 can be selected to be 2/3 of the leading length 50 (though other dimensions are equally possible) includes an upper edge portion 53 and a lower edge portion 54. The upper edge portion 53 can be angled with respect to the block upper outer surface 18 and the lower edge portion 24. The leading portion 51 does not protrude like the trailing portion 52 but is recessed back with respect to the plate 2, to the base of cutting face 33 (when fitted) to allow the protruding teeth 4 to be exposed to cut.

In the trailing third 52 of the length 50 of the curved edge plane 43, upper edge portion 53 includes a protruding upper edge portion or block ledge 53a (see figures 1 & 2) which importantly supports each tooth 4 on its trailing side or rear or side opposite to the cutting 33. The upper edge portion 53 can also be angled to optionally include a V groove 53b along its length under the ledge 53a (see figure 2). The lower edge portion 54 is planar and substantially at right angles to the plate upper surface 5 or outer lower surface 25 of block 3. Both lower portions of the lower surface 54 (ie trailing and leading) are overall curved and almost parallel to the plate edge 8 but depending which block 3 can be located in the same G:¥192009NZ AMND SPEC 29JUNE2011 EHB.DOC Recieved At IPONZ 30 June 2011 12 vertical plane as plate edge 8 or it may be set back there-from.

Block ledge 53a can be shaped as a pointed edge or a flat edge and can be located on the top or bottom of the curved side edge face 43 can extend there along, to provide shoulder support. As well as the shoulder support (by protruding portion 53 a) for the trailing side of each tooth 4 there is a leading side support (but being lower than the shoulder support) for in front of each tooth 4 right up to the bottom of the cutting face 33.

In general the set back or non flush block positioning option allows the teeth 4 to not or protrude beyond the plate edge 8 but still cut or grind as required as in all blocks the teeth 4 are still protruding beyond the block 3 to carry out its cutting or grinding. Leading angled upper portion 53 allows the protruding tooth (ie cutting face 33) to cut while the trailing upper edge portion or protruding portion or ledge 53a provides protection and rear support for each tooth 4.

As each tooth is exposed or protrudes beyond a peripheral edge face 8 of the plate 2 and/or block edge 43 cutting can occur when the plate is rotated R. The cutting or grinding is caused by a peripheral edge of the flat portion 35 of the cutting face 33 whereby the cutting has a cutting and pushing type action with the rear of each tooth being supported by block ledge 53a For the blocks 3 that are not recessed or set back from plate edge 8, the lower trailing portion and lower leading portion of leading portion 54 are positioned flush with plate edge 8 but trailing upper portion 53 can protrude beyond the plate edge 8. Upper trailing portion 53 can be like for the other blocks 3 and be V grooved having an upper surface extending with at least a portion of the outer upper surface 18 of the block 3 forming an upper trailing ledge with the actual V or groove running along under the outer upper surface 18. The protruding portion 53a forms a support behind the tooth 33.

Depending on the location of each tooth 4 in block slot 26 which such a block slot 26 extends essentially radially right through the block 3, the tooth 4 especially the bent tooth (see figure 3 c& d) is placed in the block slot 26 to be as far away as possible from the plate 2 requires the protruding portion 53a support. However if the tooth 4 is placed at the lowest G:¥192009NZ AMND SPEC 29JUNE2011 EHB.DOC Recieved At IPONZ 30 June 2011 13 point in the block slot 26 (ie closest to the plate) then the trailing ledge 37a needs to be on the lowest portion of curved edge face 43 ie in the lower trailing portion 54.

Each tooth support means 3 is designed by way of shape, size and weight to significantly increase the efficiency of grinding and serviceability whereby the teeth are better supported and protected such that all of the possible cutting width from the laterally most extending teeth will cut leaving no dead or non cutting portion(s) thereby causing the grinder to be able to plunge cut.

In the situation where two teeth are required per block 3 ie where the block slot 26 is aligned with plate slot 9 and with the block 3 not aligned, then the block 3 can be combined with various tooth 4 positions and sequenced around to get the best cutting action.

Based on figures 4 and 5 the following layout positions are examples of various teeth or tooth layouts combining flush mounting with respect to the plate 2, extending ledges or shoulders on the upper or lower portion of each block 3, spacers 40 and teeth 4 and aligned slots 11 and 26 or not. In this example layout the orientation is taken for one block 3 from the top down to the bottom with the terms matching this orientation and second aligned block 3 underneath.

In figure 5 each tooth layout (a)-(e) the left hand side represents the lower side and the right being the upper side when the block teeth and plate are assembled together when in use.

Layout position (a) - see figure 5(a) - Block (right)-upper block is flush with plate edge 8 and upper block ledge is flush with plate edge 8 Block-(left)-lower block is flush with plate edge 8 and upper block ledge protruding beyond plate edge 8 Teeth- upper bent tooth, middle straight tooth in an upper plate slot 9, straight lower tooth 4 Layout position (b) - see figure 5(b). - upper (right) block flush with plate edge 8 and lower block ledge extending lower (left) block flush with plate edge 8 and lower block ledge extending G:¥192009NZ AMND SPEC 29JUNE2011 EHB.DOC Recieved At IPONZ 30 June 2011 14 - upper straight tooth, bent middle tooth in plate slot, bent lower tooth Layout position (c) - see figure 5(c). - upper (right) block is flush with plate edge 8 and upper block ledge extending lower (left) block is flush with plate edge 8 and upper block ledge extending - bent upper teeth, bent middle tooth, straight lower tooth Layout position (d) - see figure 5(d). - upper (right) block is flush with plate edge 8 and lower block ledge extending - lower (left) block is flush with plate edge 8 and upper extending block ledge - upper straight tooth, middle straight tooth, bent lower tooth Layout position (e) - see figure 5(e).

- Block-(right) upper block is recessed from plate edge 8 and upper block ledge Spacer plate 39 - Block- (left) lower block is recessed with respect to plate edge 8 Spacer plate 39 - Block - lower block ledge protruding and spacer plate 39 Teeth -bent upper tooth, bent lower tooth - splayed apart Tooth loading patterns At every plate slot, there is a straight tooth on the opposite side in the block slot 26.

Every tooth 4 mounted on top of a tooth in a (plate) slot is a bent tooth - (two bent teeth on top of teeth per side minimum, can be more on larger plates 2) Every tooth 4 mounted at a smaller radius (on plate 2), is a bent tooth.

Every tooth 4 has the appropriate support shoulder behind it as part of the block 3.

All of the teeth are not abutting but are separately supported and mounted to the disc 2.

Figures 7-12 show a typical layout in tree stump grinder machine M (please note that only part of the machine is shown) which can be rotated in direction R. As can be seen there can be 6 pairs of blocks on one plate though any other number or configuration is possible.

Advantages G:¥192009NZ AMND SPEC 29JUNE2011 EHB.DOC Recieved At IPONZ 30 June 2011 a) Safer cutting system b) Most cutting effort goes into plunge cutting c) Reduced tooth breakage - better tooth tool life d) Reduce tooth shank wear e) Each tooth directly supported by rear ledge. f) Better use of engine torque g) Smoother cutting h) Less tip exposure i) Quicker cutting times j) Less clogging k) Reduced cleanup time due to fan effect 1) Reduced down time to replace parts m) Tooth layout allows plunge cutting n) Slotted central plate o) More than two teeth per block pairs are possible p) Fixing bolt heads not subjected to abrasive wear Variations Throughout the description of this specification, the word "comprise" and variations of that word such as "comprising" and "comprises", are not intended to exclude other additives, components, integers or steps.

It will also be understood that where a product, method or process as herein described or claimed and that is sold incomplete, as individual components, or as a "kit of Parts", that such exploitation will fall within the ambit of the invention.

For purposes of the description hereinafter, the terms "upper", "lower", "right", "left", "vertical", "horizontal", "top", "bottom", "lateral", "longitudinal" and derivatives thereof shall relate to the invention as it is oriented in the drawing figures. However it is to be understood that the invention may assume various alternative variations, except where expressly specified to the contrary. It is also to be understood that the specific devices illustrated in the attached drawings, and described in the following specification are simply exemplary embodiments of the invention. Hence specific dimensions and other physical G:¥192009NZ AMND SPEC 29JUNE2011 EHB.DOC Recieved At IPONZ 30 June 2011 16 characteristics related to the embodiments disclosed herein are not to be considered as limiting.

The plate 2 can be of sufficient thickness to allow slotting to multiples of 12.7mm deep with a minimum thickness of say 12mm. Plate 2 can be for example in a range of thickness of 12-16mm though this can be varied with the use of backing plates or spacers. The plate slots 9 are to be in pairs 180 degrees opposite on the same side of the plate 2. Block slots 26 and plate slots 9 are to be of sufficient length to accommodate the tooth shank with clearance. A minimum of two pairs of slots are required. The slots can also extend completely from one edge of the block to the other rather than only being a pocket.

The orientation of the blocks and teeth though shown to be radially can be varied to affect the effectiveness of cutting. It has especially found that providing a forward or leading rotation about say one of the bolt heads 16 for each block pair seems to work very well in cutting. The cutting of the invention is more effective in allowing greater effort of the operator in plunging rather than the accepted swaging or swinging of the machine to achieve the cutting.

Four slots equals 1 set ie two pairs. Plunge or sweep teeth 4 can be mounted to a smaller radius plate 2 with or without spacers 39 to allow faster cutting and assistance to protect the outer radius pockets from wear. The number of teeth 4 can be varied to suit the plate 2 being used. The shape, size and number of blocks 3, spacer plates 39 and slots (9 and 26) in the plate 2 and block 3 can also be varied.

The teeth 4 and matching slots 9 and 26 can be radiased or edge/corner rounded or smoothed to make the teeth 4 more robust and longer wearing. Though a V slot is shown some blocks may not have the V slot and just have the ledge 53a. The position of the ledge 53a minimally support the rear of each tooth so the ledge can be sited or located any on the curved edge face 43 ie anywhere in the upper and lower edge portions 53 and 54 It will of course be realised that while the foregoing has been given by way of illustrative example of this invention, all such and other modifications and variations thereto as would be apparent to persons skilled in the art are deemed to fall within the broad scope and ambit G:¥192009NZ AMND SPEC 29JUNE2011 EHB.DOC 17 of this invention as is hereinbefore described.

Recieved At IPONZ 30 June 2011 G:¥192009NZ AMND SPEC 29JUNE2011 EHB.DOC Recieved at IPONZ on 27 July 2011 18 What I claim is:

Claims (9)

1. Claim 1: A grinder cutter tooth support apparatus for supporting at least one cutter tooth being elongate with faces, the cutter tooth support apparatus being adapted in use for removable attachment to a rotatable grinder plate having side surfaces and an edge perimeter, of a grinder head assembly, having a rotating mass the cutter tooth support apparatus including a shaped member body, the body comprising at least one slot or pocket therein having an entrance, the slot is shaped and adapted when in use to hold at least one tooth therein, in use the body has an upper outer body surface to face away from the grinder plate and a lower outer body surface to face and abut the grinder plate, whereby side edge faces separate the upper and lower outer body surfaces, when one body is fitted to one side of the plate with lower outer body surface abutting one surface of the plate, the slot is located within the lower outer surface of the body to have its opening located in one of the body side edge faces, to allow at least one cutter tooth to be able to be fitted into the slot, to have a protruding portion beyond the slot entrance and one body side edge face so that one edge face of the said at least one cutter tooth is a cutting surface at a front and the said at least one cutter tooth having a rear surface wherein when in use the said one side edge face of the rotatable plate is oriented with respect to the body such that the one body side edge has a trailing edge portion to the rear of the said at least one cutter tooth whereby the body side edge has a protruding portion in the trailing edge portion to support all of the rear of the protruding said at least one cutter tooth portion and to enable the said at least one cutter tooth to protrude non-radially from the rotatable plate to allow only the cutting surface of the said at least one cutter tooth to protrude and to cut or grind when in use, whereby all of the rear and front of the said at least one cutter tooth is fully supported by the body except for the cutting surface only.
2. Claim 2: A grinder cutter tooth support apparatus for supporting the said cutter tooth as claimed in claim 1 wherein the tooth has an elongate shaped body with a cutting portion at the end whereby the said at least one cutter tooth is protected and supported to its cutting portion. G:¥192009NZ AMND SPEC 27July2011 EHB.DOC Recieved At IPONZ 30 June 2011 19
3. Claim 3: A grinder cutter tooth support apparatus for supporting the said at least one cutter tooth, as claimed in claim 2 wherein the plate has a curved plate edge perimeter and the body side edge can be curved to follow the curved plate edge whereby when the body having at least one cutter tooth, is fitted to the plate by body fixing means, said at least one cutter tooth is positioned to protrude from the plate edge and body side edges face, to cut when required in use.
4. Claim 4: A grinder cutter tooth support apparatus for supporting the said at least one cutter tooth, as claimed in claim 3 wherein, one of the other body side edge faces is shaped having a leading protruding portion that functions to shade the body outer surface to protect the body fixing means from wear.
5. Claim 5: A grinder cutter tooth support apparatus for supporting the said at least one cutter tooth, as claimed in claim 4 wherein, the protruding portion of the curved body edge has a grooved portion which is located immediately adjacent and in use above a ledge, whereby the grooved portion functions to allow a clear view of the side of the said at least one cutter tooth.
6. Claim 6: A grinder cutter tooth support apparatus for supporting the said at least one cutter tooth, as claimed in claim 5 wherein the body is sized and shaped by having an outer contoured face with a raised ridge for durability and weight to increase the rotating mass of the grinder head assembly.
7. Claim 7: A grinder head assembly including the grinder cutter tooth support apparatus for supporting the said at least one cutter tooth as claimed in claim 6 on each side of a rotatable grinder plate wherein the plate has a slot therein and each support apparatus has a slot whereby several configurations of the said at least one cutter tooth placement in the slots are provided to give a maximum of three teeth therein to cut and grind as required when the plate is rotated.
8. Claim 8: A grinder cutter tooth support apparatus substantially as herein before described with reference to figures of the accompanying drawings. G:¥192009NZ AMND SPEC 29JUNE2011 EHB.DOC Recieved At IPONZ 30 June 2011 20
9. Claim 9: A grinder head assembly substantially as herein before described with reference to figures of the accompanying drawings. piper: Attorneys for the Applicant croxton, David James G:¥192009NZ AMND SPEC 29JUNE2011 EHB.DOC