GB2599432A

GB2599432A - A grinder wheel

Info

Publication number: GB2599432A
Application number: GB2015621.2A
Authority: GB
Inventors: Brian Evans Howard
Original assignee: Redwood Global Ltd
Current assignee: Redwood Global Ltd
Priority date: 2020-10-01
Filing date: 2020-10-01
Publication date: 2022-04-06
Also published as: GB202015621D0

Abstract

The present invention provides a grinder wheel 100 comprising a grinder wheel body 105 rotatable in use in a rotational direction, a protection block 140 having an attachment point to releasably attach the protection block to the body and a cutting tooth positioned behind the protection block in the rotational direction, the cutting tooth having a cutting face including a first cutting edge 130 and a second cutting edge 135, wherein the cutting tooth is arrangeable in a first position in which the first cutting edge is exposed and the second cutting edge is at least partially covered by the protection block. The cutting face may further comprise third and fourth cutting edges (136, 137, figure 2) wherein the protection block is configured to entirely cover the second cutting edge and a first portion of the third and fourth cutting edges. The grinder wheel may comprise a plurality of cutting teeth and a plurality of protection blocks wherein one of the plurality of cutting teeth and associated protection blocks is positioned at a first point on the perimeter of the wheel and a second tooth and block positioned at a second point, the difference between the radius at the first and second points being equal to a height of each cutting tooth (see figure 4). Also disclosed is a protection block and a method of replacing a protection block.

Description

A GRINDER WHEEL

Field of the Invention

The present invention relates generally to a grinder wheel and finds particular, although not exclusive, utility in providing a grinder wheel for a stump grinder having replaceable cutting teeth.

Background of the Invention

In arboriculture, when a tree or other plant is felled or cut down, a stump and roots are typically left in the ground. In many circumstances, it is desirable for the stump and roots to be removed. Several methods for removing a stump have been developed and are typically used. For example, a stump may be removed by digging the ground away from around a stump such that the stump may be pulled or otherwise extracted. However, this method requires a considerable mechanical and/or physical effort and often leaves a large hole that requires backfilling. As a further example, a stump may be removed by burning the stump. Typically, a fire is built around and on top of a stump and maintained for several hours or even days. However, this method of burning a stump is not considered to be environmentally friendly and it also takes a relatively long time for the stump to burn down to an acceptable level. As another example, a stump may be removed with use of a chemical stump remover. Typically, several holes are drilled into the stump and filled with a chemical stump remover which conventionally includes potassium nitrate. The stump is then left to soften and rot, processes which are accelerated by the presence of the chemical stump remover. The stump may then be removed mechanically once softened. However, this method involves two steps, may take several weeks to complete and makes use of potentially harmful and dangerous chemicals.

A preferable method of removing a stump and roots is to remove them mechanically with a stump grinder. A stump grinder is a power tool or an attachment for construction equipment that typically includes a powered rotating grinder wheel or cutting disk. The grinder wheel typically includes several teeth spaced around its perimeter that cut away material in chips from the stump and roots. The grinder wheel may, in use, come into contact with soil, stones and other detritus which may blunt the cutting teeth and reduce the efficiency of the stump grinder. Although cutting teeth are typically provided with carbide cutting edges or surfaces, the use conditions mean that the cutting teeth have a significantly shorter operational lifespan than the other components of a stump grinder. Accordingly, a stump grinder may have replaceable cutting teeth such that a tooth may be replaced once blunt. The grinder wheel may be provided with a series of mounts to which the teeth may be attached. In addition, the teeth may be rotated such that a new cutting edge is used once a first cutting edge is blunt.

However, due to the relatively abrasive use conditions of a stump grinder, the mount and any cutting edges not presently in use may be damaged. Objects and aspects of the present invention seek to provide a grinder wheel which overcomes at least the problems with typical stump grinders.

Summary of the Invention

According to a first aspect of the present invention, there is provided a grinder wheel comprising: a grinder wheel body rotatable, in use, in a rotational direction; a protection block comprising an attachment point configured to releasably attach the protection block to the grinder wheel body; and a cutting tooth positioned behind the protection block in the rotational direction, the cutting tooth comprising a cutting face including a first cutting edge and a second cutting edge, wherein the cutting tooth is arrangeable in a first position in which the first cutting edge is exposed and the second cutting edge is at least partially covered by the protection block, and wherein the cutting tooth is alternatively arrangeable in a second position in which the second cutting edge is exposed and the first cutting edge is at least partially covered by the protection block.

A key advantage of the present invention is that the protection block provides some protection for the second cutting edge when not in use. In particular, the cutting edge not in use is at least partially covered by the protection block and is therefore not damaged to the same extent as in typical grinders, if at all. As such, the cutting edge not in use is blunted to a lesser extent, when compared to typical grinder wheels. Once the cutting edge in use becomes blunt, the tooth may be moved to the other position such that the cutting edge previously covered and therefore kept sharp, or unblunt, is presented for use.

The grinder wheel may be a stump grinder wheel. A stump grinder may be an arboreal grinder or any other known type of grinder. The grinder wheel may be configured to, in use, cut or chip away material such as a tree stump. Alternatively, the grinder wheel may be for use in trenching or mining machinery. The grinder wheel may be configured to, in use, remove soil, rock, mud, sand or any other material. The grinder wheel may be rotated, in use, by a motor or some other power supply means.

The grinder wheel being rotatable may mean that the grinder wheel moves in a rotational manner. The grinder wheel may rotate fully and repeatedly in a single direction.

Alternatively, the grinder wheel may rotate along an arc of revolution The grinder wheel may reciprocate rotationally along the arc of rotation.

The rotational direction may be the direction in which the grinder wheel is configured to rotate. The cutting tooth being positioned behind the protection block in the rotational direction may mean that the protection block precedes the cutting tooth as the grinder wheel rotates.

The attachment point may comprise a fixing such as a threaded socket suitable for receiving a bolt, a threaded rod suitable for receiving a nut, or any other known fixing or attachment means The cutting face may be the face of the cutting tooth configured and arranged to first contact the stump or other material, in use. The first and second cutting edges may be hardened with a carbide edge or tip, or similar.

The cutting tooth may be rotated, translated or moved in any other way or in any combination of movements between the first and second positions.

The protection block may comprise a work hardenable material. A work hardenable material may be any material that hardens through use or deformation. Work hardening, also known as strain hardening, is the strengthening of a material by plastic deformation. The strengthening occurs due to dislocation movements and dislocation generation within the crystal structure of the material. Any material that exhibits these properties may be a work hardenable material. The protection block may consist of a work hardenable material or materials. The protection block may be a monolithic piece of work hardenable material. The protection block may be cast formed or shaped in any other way. The work hardenable material may be austempered ductile iron (ADD. ADI has been found to have desireable qualities and has been found to improve in performance with use, due to the work hardenable nature of the material. Alternatively, the work hardenable material may be austenitic stainless steel or any other known work hardenable material.

The grinder wheel body may comprise a tooth mount. The tooth mount may be releasably or fixedly attached to the grinder wheel body. The tooth mount may be welded to the grinder wheel body. Alternatively, the tooth mount may be integral with the grinder wheel body. The cutting tooth may be attachable to the tooth mount. The cutting tooth may be attachable to the tooth mount via a fixing such as a bolt, a pin, a clamp, a friction fit, an interference fit, or by any other known means. The protection block and/or cutting tooth may be arranged to entirely cover the tooth mount in the rotational direction. In this way, the tooth mount may be protected from damage during use of the grinder wheel, thereby extending the operational life of the tooth mount. Covering in the rotational direction may mean that a cross-section of the tooth mount presented to the stump or other material being removed is covered. A front surface of the tooth mount may be covered by the protection block and/or cutting tooth. One or more other surface of the tooth mount may be exposed.

The tooth mount may comprise a first side arranged, in use, adjacent to the cutting tooth and a second side opposite the first side. The first side of the tooth mount may be a front side and the second side may be a rear side. The tooth mount may comprise a through hole passing between the first side and the second side. A fixing may be configured to attach the cutting tooth to the tooth mount via the through hole. The fixing may be positioned in the through hole. The fixing may comprise a bolt, a pin, a clamp and/or any other known fixing. Alternatively, a fixing may be provided without a through hole, such as with a friction fit or an interference fit.

The cutting tooth may be arranged between the protection block and the tooth mount. In this way, the cutting tooth may be at least partially covered and/or protected by the protection block. In particular, any cutting edge not in use may be positioned behind the protection block such that it does not come into contact with any material or detritus, in use, and therefore remains sharp.

One or both of the cutting tooth and the tooth mount may be arranged to selectively inhibit relative movement between the cutting tooth and the tooth mount in a first direction. The first direction may be the rotational direction or a direction opposite to the rotational direction.

The relative movement between the cutting tooth and the tooth mount may be selectively inhibited in both the rotational direction and the direction opposite to the rotational direction.

Relative movement between the cutting tooth and the tooth mount may be selectively inhibited in all directions except along an axis parallel to a rotational axis of the grinder wheel. Inhibit may mean prevent.

The cutting tooth may comprise an abutting face opposite the cutting face. The abutting face may be configured to abut the tooth mount. The abutting face may be shaped to be complimentary to the tooth mount. The abutting face and/or tooth mount may comprise a non-planar surface. The abutting face may include a projection. The tooth mount may include a depression shaped and sized to be complimentary to the projection such that, in use, the projection is arrangeable within the depression to selectively inhibit relative movement between the cutting tooth and the tooth mount. Alternatively, the tooth mount may comprise said projection and the abutting face may comprise said depression. Inhibit may mean prevent. The projection and depression may have a constant cross-section along an axis parallel to a rotational axis of the grinder wheel. As such, the cutting tooth may be slidably removed from the tooth mount.

The grinder wheel body may include an aperture spaced from a perimeter of the grinder wheel body. The protection block may be oriented and the grinder wheel body may be arranged such that the attachment point is accessible from the aperture in the grinder wheel body. The aperture may be an opening, a hole or a gap. The aperture may pass through the grinder wheel body. Alternatively, the aperture may not pass through the grinder wheel body. Any fixing or other attachment means used to secure the protection block to the grinder wheel may be accessed and released via the aperture. For example, if a bolt is used to secure the protection block to the grinder wheel body, the bolt head may be accessible via the aperture. In this way, the bolt or other fixing may be protected, in use.

The grinder wheel body may comprise a through hole between the aperture and the perimeter of the grinder wheel body. A fixing may be provided in the through hole and may be configured to secure the protection block to the perimeter of the grinder wheel body. For example, a bolt or a pin may be provided in the through hole. Alternatively, a fixing, such as a friction fit or an interference fit may be provided without a through hole.

A portion of the first cutting edge may be parallel to a portion of the second cutting edge. In this way, the cutting tooth may be moved between the first and second positions by rotating the cutting tooth 1800. The cutting face may be rectangular, square, hexagonal, octagonal, obround or any other known shape.

The cutting face may further comprise a third cutting edge and a fourth cutting edge. Each of the third and fourth cutting edges may extend between the first and second cutting edges. The third and fourth cutting edges may be side cutting edges. In use, the grinder wheel may be rotated and swept from side to side such that the side cutting edges contribute significantly to the cutting of the material.

The four cutting edges may be four edges of a rectangle or any other four sided shape. In the first position, the protection block may be configured to entirely cover the second cutting edge. In the first position, the protection block may be configured to entirely cover a first portion of each of the third and fourth cutting edges. In the second position, the protection block may be configured to entirely cover the first cutting edge. In the second position, the protection block may be configured to entirely cover a second portion of each of the third and fourth cutting edges. The first portions of each of the third and fourth cutting edges may not overlap with the second portions of each of the third and fourth cutting edges respectively.

The first and second portions may be halves of the cutting edges.

In this way, a portion of the side cutting edges may be exposed for use in cutting material, whereas another portion of the side cutting edges may be protected and kept sharp, or un-blunt, ready for when the cutting tooth is moved to the other position.

The grinder wheel body may include a depression in a perimeter thereof. The protection block may be arrangeable, in use, in the depression in the perimeter of the grinder wheel body. In this way, the protection block may be more easily positioned and retained. The protection block may be substantially wedge-shaped. The protection block may have a smaller cross-section at a front of the protection block, furthest from the cutting tooth, when compared to a cross-section at a rear of the protection block, closest to the cutting tooth. As such, the protection block may act to push detritus and other material away from the covered cutting edge, thereby protecting it.

The protection block may comprise a detritus guide ridge. The detritus guide ridge may project from a surface opposite to the attachment point. The detritus guide ridge may run along a longitudinal length of the protection block. The detritus guide ridge may act to push detritus and other material away from a central portion of the cutting tooth toward side regions of the cutting tooth.

The grinder wheel may comprise a plurality of cutting teeth and a plurality of associated protection blocks. A first one of the plurality of cutting teeth and associated protection block may be positioned at a first point on the perimeter of the grinder wheel body. A second one of the plurality of cutting teeth and associated protection block may be positioned at a second point on the perimeter of the grinder wheel body. The grinder wheel body may have a greater radius at the second point than at the first point. In this way, rotation of the grinder wheel without translational or lateral movement of the may cause the first tooth to remove a first portion of material and the second tooth to follow and remove a second portion of material. As such, the requirement to move the grinder is reduced. The difference between the radius at the first and second points may be equal to a height of the cutting tooth. In this way, the second tooth may cut effectively and efficiently. Furthermore, the side cutting edges of the first and second cutting teeth may align and form a continuous cutting edge, when viewed from the direction of rotation. As such, when the grinder wheel is, in use, rotated and swept from side the side, the side cutting edges may effectively remove material.

A third one of the plurality of cutting teeth and associated protection block may be positioned at a third point on the perimeter of the grinder wheel body. The third point may be between the first and second points. A radius of the grinder wheel body at the third point may be between the radii at the first and second points. In this way, the third tooth may reduce the burden and wear on the second tooth.

The first and second cutting teeth and associated protection blocks and any cutting teeth, such as the third cutting tooth, and associated protection blocks positioned therebetween, may form a first set. A second set, substantially identical to the first set, may also be provided. The second set may be positioned immediately following the first set in the rotational direction. Third, fourth, fifth and any other number of sets may be provided as appropriate.

The cutting tooth may be removable from the grinder wheel without removing the protection block. Any fixing holding the cutting tooth in position may be removed, or overcome, and the cutting tooth removed without requiring removal of the protection block. In this way, the cutting tooth may be repositioned or replaced without requiring the removal of the protection block. The cutting tooth may be translatable along an axis parallel to a rotational axis of the grinder wheel body. Alternatively, the protection block may require removal for the cutting tooth to be removed.

The protection block may be removable from the grinder wheel without removing the cutting tooth. Any fixing holding the protection block in position may be removed, or overcome, and the protection block removed without requiring removal of the cutting tooth. In this way, the protection block may be replaced without requiring the removal of the cutting tooth.

Alternatively, the cutting tooth may require removal for the protection block to be removed.

The grinder wheel may further comprise a replacement protection block that is substantially identical to the protection block. In this way, when the protection block becomes worn or damaged, it may be replaced with the replacement protection block. A kit of parts may be provided including the grinder wheel, one or more replacement protection blocks and/or one or more replacement cutting teeth.

The grinder wheel may be configured to, in use, rotate at any suitable rotational speed, such as between 300 and 5000 rpm. For example, the grinder wheel may be configured to rotate at approximately, 300 rpm, 500 rpm, 1000 rpm, 2000 rpm, 3000 rpm, 4000 rpm or 5000 rpm.

The grinder wheel may have any suitable diameter, such as in the range 0.3 to 2 metres. For example, the grinder wheel may have a diameter of approximately 0.3 metres, 0.6 metres, 1 metre, 1.5 metres or 2 metres. The size and rotational speed of the grinder wheel may be dependent on the intended use of the grinder wheel.

According to a second aspect of the present invention, there is provided a protection block configured for use in the grinder wheel of the first aspect.

According to a third aspect of the present invention, there is provided a method of replacing the protection block of the grinder wheel of the first aspect, when a replacement protection block is provided, the method comprising the steps: detaching the protection block, via the attachment point, from the grinder wheel body; removing the protection block; positioning the replacement protection block adjacent to the grinder wheel body in the position previously occupied by the protection block; and releasably attaching the replacement protection block, via an attachment point of the replacement protection block, to the grinder wheel body.

Detailed Description

Embodiments of the present invention will now be described by way of example only and with reference to the accompanying drawings, in which: Figure 1 is a side elevation view of a section of a grinder wheel; Figure 2 is a front perspective view of the section of the grinder wheel shown in Figure 1; Figure 3 is a rear perspective view of the section of the grinder wheel shown in Figures 1 and 2; and Figure 4 is a side elevation view of the grinder wheel shown in Figures 1 to 3.

Figure 1 is a side elevation view of a section of a grinder wheel 100. The grinder wheel 100 includes a substantially planar grinder wheel body 105. A tooth mount 110 is welded to the perimeter of the grinder wheel body 105. The tooth mount 110 is shown to be recessed into the perimeter edge of the grinder wheel body 105 which may provide a stronger attachment between the tooth mount 110 and the grinder wheel body 105, when compared to an arrangement in which the tooth mount 110 is not recessed into the perimeter edge of the grinder wheel body 105.

A cutting tooth 115 is releasably attached to the tooth mount 110. In the arrangement and view shown in Figure 1, the cutting tooth 115 is attached to the left side of the tooth mount 110. The tooth mount 110 includes a depression 120 in its left side and the cutting tooth 115 includes a complimentary projection 125 in its right side. The projection 125 is arranged in the depression 120 such that upwards and/or downwards movement of the cutting tooth 115 relative to the tooth mount 110 is prevented.

The cutting tooth 115 includes a first cutting edge 130, shown as an upper cutting edge, and a second cutting edge 135, shown as a lower cutting edge. The cutting face is substantially rectangular and also includes side cutting edges 136, 137. The cutting edges 130, 135, 136, 137 are carbide tipped to provide preferably mechanical properties such as improved hardness. In use, once the first cutting edge 130 has become blunt, the cutting tooth 115 may be slidably removed from the tooth mount 110 and replaced such that the second cutting edge 135 is the upper cutting edge and the first cutting edge 130 is the lower cutting edge. The cutting tooth 115 may then be used until the second cutting edge 135 is blunt and the cutting tooth 115 may then be replaced. Further details on the attachment between the cutting tooth 115 and the tooth mount 110 will be described with reference to Figure 3.

The grinder wheel 100 also includes a protection block 140 positioned on the perimeter of the grinder wheel body 105 to the left of the cutting tooth 115. The protection block 140 is shown to abut the left side of the cutting tooth 115 and cover the second cutting edge 135. The protection block 140 also partially covers the side cutting edges 136, 137. In the arrangement shown in the Figures, the protection block 140 covers the lower half of the side cutting edges 136, 137 although other amounts of coverage are envisaged. Therefore, in use, the second cutting edge 135 and the lower halves of the side cutting edges 136, 137 are protected by the protection block 140. The second cutting edge 135 and the lower halves of the side cutting edges 136, 137 may therefore remain sharp whilst the first cutting edge 130 and the upper halves of the side cutting edges 136, 137 are in use. The protection block 140 is configured and arranged such that the first cutting edge 130 and the upper halves of the side cutting edges 136, 137 are exposed. Therefore, in use, the first cutting edge 130 and the upper halves of the side cutting edges 136, 137 may be used to grind a stump or other material.

The protection block 140 is generally wedge-shaped and increases in size from left to right in the arrangement and view shown in Figure 1. The protection block 140 includes a shaped upper surface 145 to be discussed in more detail with reference to Figure 2. The grinder wheel body 105 includes a cut-out 150 positioned below the protection block 140. A bolt 155 is used to secure the protection block 140 to the grinder wheel body 105. The head of the bolt 155 is accessible via the cut-out 150. Therefore, the bolt 155 may not be damaged in use, and may be easily removed to replace the protection block 140 if required.

In use, the grinder wheel 100 is configured to rotate such that the tooth mount 110, the cutting tooth 115 and the protection block 140 move left in the arrangement and view shown in Figure 1. As such, the protection block 140 precedes the cutting tooth 115, which in turn precedes the tooth mount 110. The protection block 140 and the cutting tooth 115 are sized and arranged to entirely cover the tooth mount 110 in the direction of rotation such that the tooth mount 110 is protected. The protection block 140 may be formed from austenific ductile iron, a work hardening material, which may become harder with use. However, any other suitable material may be used.

In use, the grinder wheel 100 is rotated and swept from side to side such that the exposed cutting edges 130, 136, 137 remove material such as a tree stump in chips or other small pieces. As the grinder wheel 100 is swept from side the side, the side cutting edges 136, 11.

137 come into contact with the material to be removed and contribute significantly to the removal of the material.

Figure 2 is a front perspective view of the section of the grinder wheel 100 shown in Figure 1. As can be seen in this view, the upper surface 145 of the protection block 140 is shaped to include a central ridge 160. The ridge 160 extends along a longitudinal length of the protection block 140. The ridge 160 is configured and arranged to, in use, push detritus and other material away from a central region of the first cutting edge 130 of the cutting tooth 115. This arrangement helps to prevent damage to the cutting tooth 115 and means that the cutting edge 130 operates more efficiently. In addition, the view of Figure 2 illustrates the relative thicknesses of the components of the grinder wheel 100. The protection block 140, the cutting tooth 115 and the tooth mount 110 are all shown to have a greater thickness than the grinder wheel body 105. Having a relatively narrow grinder wheel body 105 may reduce the weight of the grinder wheel 100, thereby reducing the burden on the motor or other means configured to rotate the grinder wheel 100. The cutting tooth 115 is also shown to have substantially rectangular cutting face including the first cutting edge 130.

Figure 3 is a rear perspective view of the section of the grinder wheel 100 shown in Figures 1 and 2. A bolt 165 is used to attach the cutting tooth 115 to the tooth mount 110. The head of the bolt 165 is accessible from the rear of the tooth mount 110 such that it is protected, in use. The bolt 165 is configured to prevent relative movement of the cutting tooth 115 and the tooth mount 110. Removal of the bolt 165 allows for the cutting tooth 115 to be slidably removed from the tooth mount 110 without requiring removal of the protection block 140.

Figure 4 is a side elevation view of the grinder wheel 100 shown in Figures 1 to 3. The grinder wheel body 105 includes a central hub attachment portion 170 including fixing holes arranged such that the grinder wheel 100 can be attached to a stump grinder or other similar equipment (not shown). Nine cutting teeth 115 are positioned and equally spaced around the perimeter of the grinder wheel body 105. The nine cutting teeth 115 are generally arranged in three sets of three. A first set 175 includes three cutting teeth 1151, 1152, 1153.

The first cutting tooth 1151 is positioned on the perimeter of the grinder wheel body 105 at a first radius. The second cutting tooth 1152 is positioned on the perimeter of the grinder wheel body 105 at a second radius greater than the first radius. The third cutting tooth 1153 is positioned on the perimeter of the grinder wheel body 105 at a third radius greater than both the first and second radii. The second radius is greater than the first radius by an amount equal to half of the height of the cutting tooth 115. The third radius is greater than the second radius by an amount equal to half of the height of the cutting tooth 115. As such, the third radius is greater than the first radius by an amount equal to the height of the cutting tooth 115. Two substantially identical sets of three cutting teeth are also provided on the grinder wheel 100.

Although reference has been made to grinding a stump or other similar material, it is envisaged that the grinder wheel 100 described herein may find utility in any grinding equipment. Furthermore, although the components of the grinding wheel 100 are shown to have particular sizes and shapes, other sizes and shapes are envisaged. In addition, although Figure 4 shows nine cutting teeth 115, any number of cutting teeth, or sets of cutting teeth, are envisaged. For example, although three sets of three cutting teeth 115 have been depicted and described, two pairs or two cutting teeth 115 may be provided on a relatively smaller wheel. As a further example, four sets of three cutting teeth 115 may be provided on a relatively larger wheel. Other numbers of cutting teeth 115 and sets are envisaged. Bolts are described as the fixings at several points but any fixing, such as a pin, a clamp, or a friction fit are envisaged.

Claims

Claims 1. A grinder wheel comprising: a grinder wheel body rotatable, in use, in a rotational direction; a protection block comprising an attachment point configured to releasably attach the protection block to the grinder wheel body; and a cutting tooth positioned behind the protection block in the rotational direction, the cutting tooth comprising a cutting face including a first cutting edge and a second cutting edge, wherein the cutting tooth is arrangeable in a first position in which the first cutting edge is exposed and the second cutting edge is at least partially covered by the protection block, and wherein the cutting tooth is alternatively arrangeable in a second position in which the second cutting edge is exposed and the first cutting edge is at least partially covered by the protection block.
2. The grinder wheel of claim 1, wherein the protection block comprises a work hardenable material.
3. The grinder wheel of claim 2, wherein the work hardenable material is austempered ductile iron.
4. The grinder wheel of any preceding claim, wherein the grinder wheel body comprises a tooth mount to which the cutting tooth is attachable, and wherein the protection block and cutting tooth are arranged to entirely cover the tooth mount in the rotational direction.
5. The grinder wheel of claim 4, wherein the tooth mount comprises: a first side arranged, in use, adjacent to the cutting tooth; a second side opposite the first side; a through hole passing between the first side and the second side; and a fixing configured to attach the cutting tooth to the tooth mount via the through hole.
6. The grinder wheel of claim 4 or claim 5, wherein the cutting tooth is arranged between the protection block and the tooth mount.
7. The grinder wheel of any of claims 4 to 6, wherein one or both of the cutting tooth and the tooth mount are arranged to selectively inhibit relative movement between the cutting tooth and the tooth mount in a first direction.
8. The grinder wheel of claim 7, wherein the cutting tooth comprises an abutting face opposite the cutting face, the abutting face configured to abut the tooth mount, wherein the abutting face is shaped to be complimentary to the tooth mount.
9. The grinder of claim 8, wherein the abutting face includes a projection and the tooth mount includes a depression shaped and sized to be complimentary to the projection such that, in use, the projection is arrangeable within the depression to selectively inhibit relative movement between the cutting tooth and the tooth mount.
10. The grinder wheel of any preceding claim, wherein the grinder wheel body includes an aperture spaced from a perimeter of the grinder wheel body, wherein the protection block is oriented and the grinder wheel body is arranged such that the attachment point is accessible from the aperture in the grinder wheel body.
11. The grinder wheel of claim 10, wherein the grinder wheel body comprises a through hole between the aperture and the perimeter of the grinder wheel body and a fixing provided in the through hole configured to secure the protection block to the perimeter of the grinder wheel body.
12. The grinder wheel of any preceding claim, wherein a portion of the first cutting edge is parallel to a portion of the second cutting edge.
13. The grinder wheel of claim 12, wherein the cutting face is rectangular. 25
14. The grinder wheel of claim 12 or claim 13, wherein the cutting face further comprises a third cutting edge and a fourth cutting edge both extending between the first and second cutting edges, wherein in the first position the protection block is configured to entirely cover the second cutting edge and a first portion of each of the third and fourth cutting edges, and wherein in the second position the protection block is configured to entirely cover the first cutting edge and a second portion of each of the third and fourth cutting edges.
15. The grinder wheel of any preceding claim, wherein the grinder wheel body includes a depression in a perimeter thereof and the protection block is arrangeable, in use, in the depression in the perimeter of the grinder wheel body.10 15 20
16. The grinder wheel of any preceding claim, wherein the protection block is substantially wedge-shaped.
17. The grinder wheel of any preceding claim, wherein the protection block comprises a detritus guide ridge projecting from a surface opposite to the attachment point.
18. The grinder wheel of any preceding claim, wherein the cutting tooth is removable from the grinder wheel without removing the protection block.
19. The grinder wheel of claim 18, wherein the cutting tooth is translatable along an axis parallel to a rotational axis of the grinder wheel body.
20. The grinder wheel of any preceding claim, comprising a plurality of cutting teeth and a plurality of associated protection blocks, wherein a first one of the plurality of cutting teeth and associated protection block is positioned at a first point on the perimeter of the grinder wheel body and a second one of the plurality of cutting teeth and associated protection block is positioned at a second point on the perimeter of the grinder wheel body, wherein the grinder wheel body has a greater radius at the second point than at the first point.
21. The grinder wheel of claim 20, wherein the difference between the radius at the first and second points is equal to a height of the cutting tooth.
22. The grinder wheel of claim 21, wherein a third one of the plurality of cutting teeth and associated protection block is positioned at a third point on the perimeter of the grinder wheel body, between the first and second points, and a radius of the grinder wheel body at the third point is between the radii at the first and second points.
23. The grinder wheel of any preceding claim, further comprising a replacement protection block that is substantially identical to the protection block.
24. A protection block configured for use in the grinder wheel of any preceding claim.
25. A method of replacing the protection block of the grinder wheel of claim 23, the method comprising the steps: detaching the protection block, via the attachment point, from the grinder wheel body; removing the protection block; positioning the replacement protection block adjacent to the grinder wheel body in the position previously occupied by the protection block; and releasably attaching the replacement protection block, via an attachment point of the replacement protection block, to the grinder wheel body.