Abrasive tools and tool holders for processing concrete and stone surfaces

Abstract

An abrasive tool (200) for a floor grinder (100), the tool (200) comprising a carrier plate (310) extending in a plane (P), where the carrier plate (310) is arranged to support one or more abrasive elements (210) on an outer face (315) of the carrier plate (310), where two sides (220a, 220b) extend out from an inner face of the carrier plate (310) in a direction transversal to the plane (P), where the two sides (220a, 220b) are separated from each other and form an acute angle (a) in the plane (P) relative to each other, where an apex of the acute angle (a) between the sides (220a, 220b) points towards an inner radial edge (I) of the abrasive tool (200) and away from an outer radial edge (O) of the abrasive tool (200), where the two sides (220a, 220b) extend towards the outer radial edge (O) of the abrasive tool (200) up to a distance (D1 ) from the outer radial edge (O).

Description

[0001] TITLE

[0002] ABRASIVE TOOLS AND TOOL HOLDERS FOR PROCESSING CONCRETE AND STONE SURFACES

[0003] TECHNICAL FIELD

[0004] The present disclosure relates to floor grinders and abrasive tools for grinding and polishing hard material surfaces such as concrete and stone surfaces. There are disclosed abrasive tools for use in grinding and polishing concrete and stone surfaces, systems for abrasive processing of concrete and stone surfaces, and manufacturing methods for producing abrasive tools.

[0005] BACKGROUND

[0006] Concrete surfaces are commonly used for flooring in both domestic and industrial facilities. The size of concrete surface floors ranges from a few square meters for a domestic garage floor to thousands of square meters in larger industrial facilities. Concrete surfaces offer a cost efficient and durable flooring alternative and have therefore gained popularity over recent years.

[0007] A floor grinder can be used to efficiently process a concrete surface in order to, e.g., obtain a level surface having a uniform topology and / or a surface having a desired surface texture. Floor grinders can also be used to polish concrete surface in order to obtain a glossy surface finish. Most floor grinders can also be used to process stone surfaces, as well as other hard material surfaces.

[0008] EP1955809A1 describe tools and tool holders for efficient and convenient processing of concrete surfaces. However, further improvements are desired.

[0009] SUMMARY

[0010] It is an objective of the present disclosure to provide improved tools and tool holders for processing hard material surfaces such as concrete and stone surfaces. This objective is at least in part obtained by an abrasive tool for a floor grinder. The tool comprises a carrier plate extending in a plane, where the carrier plate is arranged to support one or more abrasive elements on an outer face of the carrier plate, i.e., the side facing the concrete or stone surface in use. Two sides extend out from an inner face of the carrier plate (the side facing away from the surface in use) in a direction transversal to the plane. The two sides are separated from each other and form an acute angle in the plane relative to each other. An apex of the acute angle between the sides points in direction of an inner radial edge of the abrasive tool and away from an outer radial edge of the abrasive tool. At least one of the two sides extends towards the outer radial edge of the abrasive tool up to a distance from the outer radial edge, i.e., at least one of the two sides, and preferably both sides, do not extend all the way up to the outer radial edge of the abrasive tool, leaving respective gaps between the outer radial end of the side and the outer radial edge of the abrasive tool. This is an advantage since the abrasive elements attached on the outer face of the carrier plate may then extend past a pair of slots formed on a tool carrier to hold the abrasive tool, as will be explained in the following. The abrasive tool can be held securely by a tool holder thanks to the acute angle formed between the two sides of the abrasive tool. Consequently, the respective extension lengths of the two sides measured in direction from the inner radial edge of the abrasive tool to the outer radial edge of the abrasive tool are smaller than an extension length of the abrasive tool measured from its inner radial edge to its outer radial edge. Thus, the abrasive tool is configured to extend radially past a tool holder mechanism that engages the sides. This way an increased surface area becomes available for mounting abrasive elements on the carrier plate.

[0011] According to some aspects, a difference between the extension length of the abrasive tool measured from its inner radial edge to its outer radial edge, and the extension lengths of the two sides is at least 1 mm and preferably at least 3mm. In other words, the gap between the sides and the outer radial edge of the abrasive tool is at least 1 mm and preferably more than 3mm. This size of the gap allows, e.g., a tool holder to be manufactured with sufficient mechanical strength. A transition between the carrier plate and the two sides can be rounded, which is a preferred transition in case the sides are formed by bending a sheet metal material. The radius of the rounded transition may be between 1 -10mm.

[0012] The two sides may also be formed so as to at least partly extend towards each other in order to engage a tool holder in gripping engagement. This improves the attachment between the abrasive tool and its tool holder. The two sides may for instance be formed such as to extend away from the carrier plate at an acute angle relative to each other, measured normal to the plane of the carrier plate.

[0013] According to some aspects, an end portion of at least one of the sides facing in direction of the outer radial edge of the abrasive tool comprises a protrusion. This protrusion can be used to key the abrasive tool to a given tool holder, such that only the correct type of abrasive tool is used with a given tool holder. A tool holder without a recess matched to the protrusion will not be able to correctly receive the abrasive tool having the protrusion. It is also possible to arranged one or more protrusions on the tool holder that are matched to corresponding recesses formed on the end portion of at least one of the sides facing in direction of the outer radial edge of the abrasive tool.

[0014] According to some aspects, an edge of at least one of the sides facing away from the carrier plate is bent towards alignment with the plane. This C-shaped side element improves the attachment between tool and tool holder, which is an advantage. At least one groove may also be formed extending on one of the sides and facing the other of the sides. The groove may cooperate with a corresponding protrusion formed on the tool holder to improve the attachment between tool and tool holder.

[0015] The carrier plate optionally comprises an abutment arranged at the inner radial edge and extending normally to the plane. This abutment prevents the abrasive tool from moving too far in the radial direction of the tool holder in use. The abutment can also be used to key a given type of abrasive tool to a matching tool holder. Le., in case the abrasive tool comprises the abutment, then it can only be assembled together with tool holders arranged to accommodate the abutment in the received position.

[0016] The objective is also at least in part obtained by a tool holder for supporting one or more abrasive tools on concrete and / or stone surface processing equipment. The tool holder comprises a planar member arranged to be rotatably driven by the surface processing equipment. A plurality of slots extend from respective inner radial ends to respective outer radial ends in tangentially separated pairs on the planar member, where two slots in a pair form an acute angle relative to each other.

[0017] According to some aspects, at least one slot in each pair is terminated at its outer radial end, to abut a side wall of an abrasive tool to prevent the abrasive tool from moving too far out radially on the tool holder. Some or all slots may be open at the inner radial ends, i.e., towards the center of the planar member. At most one slot in each pair may also be open at its outer radial end.

[0018] According to some aspects, at least two slots from different pairs are joined at their respective inner radial ends to form a V-shape. This is an advantage in particular if a milling machine is used in production since the V-shaped slot can be milled in one pass.

[0019] According to some aspects, a ridge extends tangentially out from a side wall of at least one of the slots. This ridge is configured to cooperate with a corresponding groove formed in the abrasive tool, to improve the attachment between abrasive tool and tool holder.

[0020] A center slot may also be formed that extends along a center line of the planar member between two slots in a pair of slots. The center slot is terminated at its outer radial end to engage a corresponding abutment formed on an abrasive tool. This also prevents the abrasive tool from moving too far out on the tool holder in the radial direction.

[0021] According to some aspects, at least one aperture is formed in the planar member between two slots in a pair of slots. The at least one aperture is arranged to allow a flow of air to pass from one side of the planar member to the other side of the planar member. This flow of air advantageously cools an abrasive tool supported on the tool holder by the pair of slots.

[0022] The objective is also at least in part obtained by a tool holder for supporting one or more abrasive tools on concrete and / or stone surface processing equipment. The tool holder comprises a planar member arranged to be rotatably driven by the surface processing equipment. A plurality of undercut shoulder elements extend out from a face of the planar member, where each undercut shoulder element has two opposing sides extending from an inner radial edge of the undercut shoulder element to an outer radial edge of the undercut shoulder element, where the opposing sides form an acute angle relative to each other. At least one abutment extend out tangentially from the opposing sides in connection to the outer radial edge of the undercut shoulder element.

[0023] Generally, all terms used in the claims are to be interpreted according to their ordinary meaning in the technical field, unless explicitly defined otherwise herein. All references to “a / an / the element, apparatus, component, means, step, etc.” are to be interpreted openly as referring to at least one instance of the element, apparatus, component, means, step, etc., unless explicitly stated otherwise. The steps of any method disclosed herein do not have to be performed in the exact order disclosed, unless explicitly stated. Further features of, and advantages with, the present invention will become apparent when studying the appended claims and the following description. The skilled person realizes that different features of the present invention may be combined to create embodiments other than those described in the following, without departing from the scope of the present invention.

[0024] BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The present disclosure will now be described in more detail with reference to the appended drawings, where

[0026] Figures 1A-B illustrate an example floor grinder;

[0027] Figures 2A-B shows an example concrete surface processing tool holder; Figure 3 is a perspective view of a concrete surface processing tool;

[0028] Figures 4A-B illustrate an example concrete surface processing tool;

[0029] Figures 5A-D illustrate an example concrete surface processing tool;

[0030] Figures 6A-B shows an example concrete surface processing tool holder;

[0031] Figures 7A-B shows an example concrete surface processing tool holder;

[0032] Figures 8-9 show details of an example concrete surface processing tool;

[0033] Figures 10A-B show details of an example concrete surface processing tool;

[0034] Figures 1 1 A-B show details of an example concrete surface processing tool;

[0035] Figures 12A-C show details of an example tool holder; and

[0036] Figures 13A-B are flow charts illustrating a manufacturing and use methods.

[0037] DETAILED DESCRIPTION

[0038] The invention will now be described more fully hereinafter with reference to the accompanying drawings, in which certain aspects of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments and aspects set forth herein; rather, these embodiments are provided by way of example so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Like numbers refer to like elements throughout the description.

[0039] It is to be understood that the present invention is not limited to the embodiments described herein and illustrated in the drawings; rather, the skilled person will recognize that many changes and modifications may be made within the scope of the appended claims.

[0040] Figures 1A and 1 B illustrate an example floor grinder 100 for processing a concrete and / or stone surface 101. It is appreciated that most floor grinders can be used to process both concrete and stone as well as other hard material surfaces such as metal surfaces and some plastic surfaces. However, some tools and machines are tailored specifically for concrete, and some are tailored specifically for stone. The teachings herein are applicable to all tools and machines for processing hard material surfaces and in particular concrete and stone surfaces. The example floor grinder 100 comprises a first electric motor 110 arranged to rotatably drive a number of tool holders 120 about respective axes A. The tool holders 120 on the example machine 100 are comprised on a rotatable body section 130. This body section is often referred to as a planet. A second optional electric motor 115 is arranged to rotate the planet about a central axis B. The type of drive system shown in Figure 1 is generally referred to as a planetary drive system. Abrasive tools of varying grit and specifications can be mounted onto the tool holders 120. The grit, grit number, or grit size of a tool indicates the abrasive grade of the tool. A lower grit number indicates a coarse abrasive tool, while a higher grit number indicates a finer abrasive product. A low grit number tool normally removes more material from the surface compared to a high grit number tool.

[0041] Electrically powered floor grinders like that illustrated in Figure 1 are generally known. Floor grinders driven by combustion engines, such as propane-fueled combustion engines, are also known. The tools and techniques disclosed herein are applicable with both electrically powered and combustion engine powered machines.

[0042] The machine 100 can be used to grind and to polish concrete and stone surfaces. Depending on the desired concrete processing operation to be performed, tools of varying grit size are attached to the tool holders 120. The grit size of an abrasive element is usually stated as a number that is inversely related to the abrasive particle size. A small number such as 20 or 40 indicates a coarse grit, while a large number such as 1800 indicates a fine grit. The techniques disclosed herein may be used with advantage for a wide variety of different grit sizes, ranging from, e.g., 30 to about 3000.

[0043] A radial direction R is to be construed broadly herein to mean a direction pointing generally outwards from a center region of an object arranged to rotate about an axis of rotation comprised in the center region. A radial direction R is for instance not necessarily exactly aligned with a radius of an annular member arranged to rotate about a center axis of rotation. Rather, a radial direction is some general direction forming an acute angle with the radius of the annular member. A tangential direction T is transversal to the radial direction R. That a first object is located radially outwards relative to a second object means that the first object is further from the rotation center compared to the second object.

[0044] Figure 2A illustrates a tool holder 120 with an example abrasive tool 200 mounted thereon. Compared to the tool holder described in, e.g., EP1955809A1 , this tool holder uses angled slots 230 which receive wings or downward extending sides of an abrasive tool carrier plate. When the abrasive tool is pushed outwards in the radial direction R it is held in position by the retaining force generated between the wings and the planar member 220. This retaining force comprises a friction-based component, relying on the friction generated between the sides of the abrasive tool and the tool holder.

[0045] An advantage of using a planar annular member with slots instead of undercut shoulder elements as in EP1955809A1 is that the height of the tool holder in direction normal to the planar member decreases, which improves stability of the machine 100. The reduction in height may also allow the grinding tool to enter in under objects at the work site such as radiators and shelving that can then be left in place during concrete and stone surface processing, which is an advantage. A tool holder 120 based on a planar member with slots as in Figure 2A can also be produced in a cost efficient manner. Since the slots 230 are terminated at respective outer radial ends, i.e., do not extend radially past the outer radial edge of the planar member 220, the abrasive elements are prevented from moving too far out in the radial direction R where they can get caught by external objects at the work site such as edges of walls and the like. This is particularly important on tool holders made out of plastic that will soften due to the heat generated in use. It is an advantage that the periphery of the planar member 220 is circular, i.e., that the planar member is annular, since this reduces the risk that the tool holder gets caught on edges. Having a discshaped tool holder is also beneficial for structural integrity of the overall assembly. Figure 2A-B, Figure 3, and Figures 4A-B illustrate an abrasive tool 200 suitable for use with the floor grinder 100, and also with similar types of surface processing equipment. The tool 200 comprises a carrier plate 310 that extends in a plane P. The carrier plate 310 is arranged to support one or more abrasive elements 210 on an outer face 315 of the carrier plate. The outer face of the carrier plate is the side that faces the surface 101 in use. The inner face of the carrier plate is the side opposite to the outer face. The abrasive elements may have various shapes and chemical composition, and be of different grit size as discussed above. An abrasive element may be positioned within the edges of the carrier plate or extend outside of the carrier plate.

[0046] The carrier plate 310 has two sides 220a, 220b that extend out from its inner face in a direction transversal to the plane P, away from the surface 101 in use. The sides may also be referred to as the wings of the abrasive tool 200.

[0047] Each side 220 extends along the carrier plate 310 from an inner radial edge I of the carrier plate 310 to an outer radial edge O of the carrier plate 310. The sides may extend out from the lateral edges of the carrier plate 310 as in the examples shown in the drawings, of from a location tangentially distanced from the lateral edge of the carrier plate, i.e., such that the carrier plate extends past the sides in the tangential direction T.

[0048] The two sides 220a, 220b are separated from each other and form an acute angle a in the plane P relative to each other, that is preferably configured to match the acute angle y formed by the slots 230 in a pair of slots on the tool holder 120. Thus, the abrasive tool 200 can be inserted into the slots at the inner radial edge and slided radially outwards, whereby the sides of the abrasive tool engage the sides of the slots to hold the abrasive tool in position.

[0049] At least one of the two sides, and preferably both sides, extend towards the outer radial edge O of the abrasive tool 200 up to a distance D1 from the outer radial edge O, leaving a gap between the outer radial end of the side and the outer edge of the abrasive tool. It is noted that the gaps on each side may be of different lengths, and even non-existent on one of the sides. The respective extension lengths La, Lb of the two sides measured in the general radial direction R as indicated in Figure 3 are, in other words, smaller than an extension length L of the carrier plate 310 in the radial direction R and / or of an abrasive segment 210 mounted on the carrier plate 310. This means that the outer radial part of the abrasive tool 200 (either the carrier plate and / or the abrasive segment mounted on the carrier plate) extends past the sides by a distance D1. Thus, as the abrasive tool is mounted onto the tool holder 120, the carrier plate extends past the slot. This means that more carrier plate surface is made available for abrasive tools, which is an advantage. It is noted that the inner radial edges of the sides 220 are aligned with the inner radial edge of the carrier plate 310 in most of the drawings, although this is not strictly necessary. The two sides may also extend toward the inner radial edge I of the abrasive tool 200 up to a distance from the inner radial edge I, leaving a gap between the inner radial end of the side and the inner edge of the abrasive tool.

[0050] The difference D1 between the extension length L of the carrier plate 310 in the radial direction R and the extension lengths La, Lb of the two sides in the radial direction R is preferably at most half of the extension length L, i.e., La>L / 2 and Lb>L / 2. In other words, the two sides 220 preferably extend over more than half of the carrier plate 310 in the radial direction R. The distance D1 in the radial direction R between the extreme point of the carrier plate 310 and the extreme point of both sides 220a, 220b at the outer end of the carrier plate 310 is at least 1 mm.

[0051] The transition between the carrier plate 310 and the two sides 220a, 220b is preferably rounded. The radius of the rounded transition may be configured between 1 -10mm. This rounding of the transition between carrier plate and sides may be matched to the shape of the slot aperture, which can be rounded by the same or similar radius. It may be advantageous to not round the slot aperture more than necessary, and instead make the radius on the tool smaller.

[0052] The two sides 220a, 220b are preferably arranged to at least partly extend towards each other to engage a tool holder 120 in gripping engagement. The two sides may, for instance, extend away from the carrier plate 310 at an acute angle [i towards each other, measured normal to the plane as exemplified in Figure 4A. This causes the abrasive tool to be pulled towards the tool holder in direction normal to the plane P as it is pushed radially outwards, which is desired since this reduces rattle and vibration during concrete and / or stone surface processing.

[0053] To hinder the tool from moving too far out radially on the tool holder in use, where there is a risk that the tool may hit edges such as walls and the like and be pushed off the holder, the carrier plate 310 comprises an optional abutment 320 arranged at its inner radial edge I and extending normal to the plane P, as illustrated, e.g., in Figure 3 and in Figure 4A. This abutment 320 is arranged to mate with a center slot 240 formed in the tool holder 120 that extends along a center line 250 of the planar member 220 between two slots in a pair of slots. The center slot 240 is terminated at its outer radial end to engage the abutment 320 formed on the abrasive tool 200 at a desired radial position of the tool relative to the tool holder. This arrangement may also improve the engagement between the abrasive tools and the tool holder, and prevent the abrasive tool from getting stuck in the tool holder due to development of too much friction in use. Note that the abutment 320 is entirely optional. The space used up by this abutment can instead be used to increase the grinding segment area.

[0054] Figures 5A-D illustrate an example abrasive tool according to the teachings herein. Note in particular the gap D1 formed between the sides 220a, 220b and the outer radial edge of the carrier plate 310. It is appreciated that the size of the gap D1 formed between one of the sides 220a and the outer radial edge O of the carrier plate 310 may be different compared to the size of the gap D1 formed between the other of the sides 220b and the outer radial edge of the carrier plate 310. One of the gaps may even be non-existent, i.e., D1 may equal zero for one of the sides 220a, 220b.

[0055] Figures 6A-B illustrate an example tool holder with V-shaped slots 230 that extend radially on the tool holder in pairs. Figures 7A-B show an abrasive tool attached to the tool holder. Each abrasive tool 200 is inserted into a pair of slots at the inner end and pushed radially outwards. The distance between the slots in a pair of slots then increases due to the angle y, and the sides 220 on the tool thus engage the tool holder in a friction-based engagement.

[0056] According to some aspects, at least one aperture 610 is formed in the planar member 220 between the two slots 230 in a pair of slots. There are preferably more than one aperture 610 formed in the planar member 220, such as one or more apertures between the two slots in each pair of slots on the tool holder 120. The at least one aperture 610 is arranged to allow a flow of air to pass from one side of the planar member to the other side of the planar member, i.e., from the front side or outer face 315 of the planar member facing the surface 101 in use to the back side. This flow of air advantageously cools an abrasive tool supported on the tool holder. A matching groove or recess may be formed in the carrier plate 310 to promote the flow of air and improve the cooling effect from the flow of air passing through the aperture 610.

[0057] With reference to Figure 8, an end portion of at least one of the sides 220a, 220b facing in direction of the outer radial edge O of the abrasive tool 200 optionally comprises a protrusion 800. This protrusion is configured to be received in a corresponding recess formed in the tool holder 120 in a key-like manner, where only an abrasive tool having the right type of protrusion can be used with a given tool holder. The protrusion and the recess can be keyed to each other to prevent use of the wrong type of tools with a given tool holder. A tool holder may generally be formed with a combination of protrusions and recesses matched to a specific tool. Suppose for instance that a surface processing operation will involve grinding with a given grit size. A work leader may then provide tool holders corresponding to the surface processing operation and thus ensure that the correct type of tools will be used. A C- shaped wing may also be used with the same effect, i.e., a wing that is bent to form a portion that extends into a groove or radial recess formed in the tool holder 120. The form of the C-shaped wing can be matched to grooves formed in the tool holder slots in the same key-like manner. Some example abrasive tools 200 comprising C-shaped sides, or wings, are illustrated in Figures 10A- B and in Figures 11A-B. In Figures 10A-B both sides have the C-shape 1000, while in Figures 1 1 A-B only one of the sides are C-shaped 1000.

[0058] It is also possible to form at least one groove 900 that extends on one of the sides 220a, 220b and facing the other of the sides 220b, 220a, as illustrated in Figure 9. A corresponding ridge 910 that extends tangentially out from a side wall of at least one of the slots 230 can then be formed at the side of the slot to mate with the groove in key-like manner. This ridge and groove combination improves the friction between tool and tool holder, and also guides the tool as it is slid radially outwards into locking position on the tool holder.

[0059] The tool holder 120 illustrated in Figure 2A supports one or more abrasive tools 200. The tool holder 120 comprises a planar member 220 arranged to be rotatably driven by the surface processing equipment 100. The planar member 220 may be formed as an annular planar member as in the example of Figure 2A, having a circular outer periphery and an inner aperture where it attaches to the concrete processing equipment. However, the planar member may also be formed as a polygon, such as a pentagon, a hexagon or the like. The center part of the planar member 220 may take on various forms and functions, but it normally comprises an interface to attaching the tool holder to the drive unit of the surface processing equipment 100. The planar member 220 may extend to a maximum radius between 10-1000mm, or more. In other words, the techniques disclosed herein can be used with a large variety of different sized concrete and / or stone surface processing tools. A radius of about 100-200 mm is, however, preferred for many common surface processing tasks.

[0060] A plurality of slots 230 extend radially in tangentially separated pairs on the planar member 220, from respective inner radial ends to respective outer radial ends. Each pair of slots 230 is arranged to receive and to hold an abrasive tool 200. The abrasive tool to be held in position by the slots comprises sides or wings that are designed to enter into the slots from a direction normal to the planar member, whereupon the abrasive tool can be slid into locking position by moving the abrasive tool radially outwards such that friction develops between the abrasive tool sides and the planar member. The two slots in a pair form an acute angle y relative to each other as illustrated in Figure 2A. The acute angle y is measured in a plane of the planar member 220, which plane aligns with the plane P of the abrasive tool 200 in use. This angle y acts like a wedge which engages the abrasive tool to hold it in position. The slots are preferably also formed with angled side walls relative to a normal of the planar member 220 as illustrated in Figure 2B, and matched to a corresponding angle of the abrasive tool sides. This angle “pulls” the abrasive tool 200 towards the planar member as it enters the operating position on the planar member.

[0061] At least one, and preferably all of the slots 230, are terminated in the radial direction at respective inner radial ends and outer radial ends. The slots 230 can for instance be formed as elongated apertures extending through the planar member 220 with continuous periphery. The slots need not extend all the way through the planar member, but can also be formed as recesses in the planar member. The radial end points of the slots prevent the abrasive tools from passing beyond the slot in the radial direction. This is an advantage, in particular since radial outwards movement on the planar member is prevented in an efficient manner. At least two slots from different pairs can also be joined at their respective inner radial ends to form a V-shape, as illustrated in Figure 2A. It is noted that the V-shaped apertures formed in the planar member 220 are still terminated radially such that an abrasive tool cannot pass beyond the slot in the radial direction.

[0062] A distance D2 measured in the radial direction R on the planar member 220, as illustrated in, e.g., Figure 2A, between the radial extreme point of the planar member 220 and the outer radial end O of at least one slot 230 is preferably at least 1 mm. A length of at least one slot 230 measured in the radial direction R on the planar member 220 is preferably between 5-500mm, i.e., the size of the slots may vary a lot between embodiments.

[0063] Different tool holders may be arranged to hold different numbers of abrasive tools. These tool holders may be keyed to the intended tool type using the keying arrangements discussed above in connection with Figure 8 and Figure 9. By keying the tool holders in this manner, there is also a possibility of making holders that only fits certain tools, for example flexible holders could be made to just fit polishing tools, which is an advantage.

[0064] Figures 12A-C illustrates another example tool holder 1200 for supporting one or more abrasive tools 200 on concrete and / or stone surface processing equipment 100. The tool holder 120 comprises the same type of planar member 220 discussed above that is arranged to be rotatably driven by the surface processing equipment 100. In this case a plurality of undercut shoulder elements 1210 extend out from the lower face of the planar member 220, i.e., the face of the planar member directed towards the concrete or stone surface in use. Each undercut shoulder element 1210 has two opposing sides 1220a, 1220b as illustrated in, e.g., Figure 12C extending radially with respect to the planar member 220, where the opposing sides form an acute angle y relative to each other in the plane P. Abutments 1230a, 1230b extend out tangentially from the opposing sides. These abutments engage the sides of the abrasive tool as it is slid onto the undercut shoulder to be held in position. The abutments prevents the tools from entering out too far in the radial direction. The abutments also prevent the abrasive tool from being pushed too far onto the undercut shoulder, such that it can be more easily removed when desired, i.e., slid back radially inwards.

[0065] A length D3 of the abutments 1230a, 1230b in the radial direction R is preferably at least 1 mm, and more preferably matched to the distance D1 of the abrasive tool discussed above in connection to Figure 3.

[0066] Figure 13A is a flow chart that illustrates an example method for producing an abrasive tool 200. The method comprises providing Sa1 material for a carrier plate 310 extending in a plane P, where the carrier plate 310 is arranged to support one or more abrasive elements 210 on an outer face 315 of the carrier plate 310, and forming Sa2 two sides 220a, 220b that extend out from an inner face of the carrier plate 310 in a direction transversal to the plane P.

[0067] The two sides 220a, 220b are separated from each other and form an acute angle a with each other, where an apex of the acute angle a between the sides 220a, 220b points towards an inner radial edge I of the abrasive tool 200 and away from an outer radial edge O of the abrasive tool 200. At least one of the two sides 220a, 220b also extends in a respective extension direction from the inner radial edge I towards the outer radial edge O up to a distance D1 from the outer radial edge O of the abrasive tool 200, as illustrated in the drawings.

[0068] The parts of the abrasive tool 200 that support the abrasive element 210 or elements can be formed in plastic or in metal, or in a combination of plastic and metal.

[0069] In case of a metal abrasive tool carrier plate, the method optionally also comprises forming Sa21 the two sides 220a, 220b by bending the carrier plate material along lines angled by the acute angle y relative to each other.

[0070] The method optionally comprises cutting Sa1 1 the material for the abrasive tool carrier plate (and optionally also the sides) out from a piece of sheet metal. Thus, an abrasive tool according to the teachings herein may be formed in an efficient manner by cutting a suitably formed piece out sheet metal from a larger piece of sheet metal, and then forming the sides by bending the cut-out piece of sheet metal.

[0071] In case of a plastic material abrasive tool carrier plate, the method optionally also comprises forming Sa22 the two sides 220a, 220b and the carrier plate 310 by molding the plastic material as one integrally formed unit.

[0072] The method preferably also comprises attaching Sa3 one or more abrasive elements onto the outer face of the carrier plate, although the abrasive elements may also be attached in a separate process.

[0073] Figure 13B illustrates a method for processing a concrete or stone surface 101 . The method comprises providing Sb1 surface processing equipment 100, assembling Sb2 at least one tool holder 120 according to the above discussion onto the surface processing equipment 100, attaching Sb3 one or more abrasive tools as described herein onto the at least one tool holder 120, and processing Sb4 the concrete or stone surface 101 by the surface processing equipment 100.

Claims

CLAIMS1 . An abrasive tool (200) for a floor grinder (100), the tool (200) comprising a carrier plate (310) extending in a plane (P), where the carrier plate (310) is arranged to support one or more abrasive elements (210) on an outer face (315) of the carrier plate (310), where two sides (220a, 220b) extend out from an inner face of the carrier plate (310) in a direction transversal to the plane (P) and away from the outer face (315), where the two sides (220a, 220b) are separated from each other and form an acute angle (a) in the plane (P) relative to each other, where an apex of the acute angle (a) between the sides (220a, 220b) points in direction of an inner radial edge (I) of the abrasive tool (200) and away from an outer radial edge (O) of the abrasive tool (200), where at least one of the two sides (220a, 220b) extends towards the outer radial edge (O) of the abrasive tool (200) up to a distance (D1 ) from the outer radial edge (O).

2. The abrasive tool (200) according to claim 1 , where respective extension lengths (La, Lb) of the two sides (220a, 220b) measured in direction from the inner radial edge (I) of the abrasive tool (200) to the outer radial edge (O) of the abrasive tool (200) are smaller than an extension length (L) of the abrasive tool (200) measured from its inner radial edge (I) to its outer radial edge (O).

3. The abrasive tool (200) according to claim 2, where a difference (D1 ) between the extension length (L) of the abrasive tool (200) and the extension lengths (La, Lb) of the two sides is at least 1 mm and preferably at least 3mm.

4. The abrasive tool (200) according to any previous claim, where a transition between the carrier plate (310) and the two sides (220a, 220b) is rounded.

5. The abrasive tool (200) according to claim 4, where a radius of the rounded transition is between 1 -10mm.

6. The abrasive tool (200) according to any previous claim, where the two sides (220a, 220b) at least partly extend towards each other to engage a tool holder (120) in gripping engagement.

7. The abrasive tool (200) according to claim 6, where the two sides extend away from the carrier plate (310) at an acute angle (J3) relative to each other measured normal to the plane (P).

8. The abrasive tool (200) according to any previous claim, where an end portion of at least one of the sides (220a, 220b) facing in direction of the outer radial edge (O) of the abrasive tool (200) comprises a protrusion (800).

9. The abrasive tool (200) according to any previous claim, where an edge of at least one of the sides (220a, 220b) facing away from the carrier plate (310) is bent towards alignment with the plane (P).

10. The abrasive tool (200) according to any previous claim, where at least one groove (900) extends on one of the sides (220a, 220b) and facing the other of the sides (220b, 220a).11 . The abrasive tool (200) according to any previous claim, where the carrier plate (310) comprises an abutment (320) arranged at the inner radial edge (I) and extending normal to the plane (P).

12. Surface processing equipment (100) comprising an abrasive tool (200) according to any of claims 1 -1 1.

13. A tool holder (120) for supporting one or more abrasive tools (200) on surface processing equipment (100), the tool holder (120) comprising a planar member (220) arranged to be rotatably driven by the surface processing equipment (100), where a plurality of slots (230) extend from respective inner radial ends to respective outer radial ends in tangentially separated pairs on the planar member (220), where two slots in a pair form an acute angle (y) relative to each other.

14. The tool holder (120) according to claim 13, where at least one slot (230) in each pair is terminated at its outer radial end.

15. The tool holder (120) according to claim 13 or 14, where at least two slots from different pairs are joined at their respective inner radial ends to form a V- shape.

16. The tool holder (120) according to any of claims 13-15, where a distance (D2) measured in direction of a slot (230) from the radial end of the slot to the radial extreme point of the planar member (220) is at least 1 mm.

17. The tool holder (120) according to any of claims 13-16, where a length of at least one slot (230) measured from its inner radial end to its outer radial end on the planar member (220) is between 5-500mm.

18. The tool holder (120) according to any of claims 13-17, where a ridge (910) extends tangentially out from a side wall of at least one of the slots (230).

19. The tool holder (120) according to any of claims 13-18, where a center slot (240) extends along a center line (250) of the planar member (220) between two slots in a pair of slots, where the center slot (240) is terminated at its outer radial end to engage an abutment (320) formed on an abrasive tool (200).

20. The tool holder (120) according to any of claims 13-19, where at least one aperture (610) is formed in the planar member (220) between two slots in a pair of slots, where the at least one aperture is arranged to allow a flow of air to pass from a front side of the planar member (220) to a back side of the planar member (220).21 . The tool holder (120) according to any of claims 13-20, where at least 4 pairs of slots are formed in the planar member (220).

22. The tool holder (120) according to any of claims 13-21 , where the planar member (220) extends to a radius between 10-1000mm.

23. The tool holder (120) according to any of claims 13-22, where the slots (230) extend through the planar member (220) from one side of the plane (P) to the other side.

24. The tool holder (120) according to any of claims 13-23, where the planar member (220) is an annular planar member.

25. Surface processing equipment (100) comprising a tool holder (120) according to any of claims 12-24.

26. A tool holder (1200) for supporting one or more abrasive tools (200) on surface processing equipment (100), the tool holder (120) comprising a planar member (220) arranged to be rotatably driven by the surface processing equipment (100), where a plurality of undercut shoulder elements (1210) extend out from a face of the planar member (220), where each undercut shoulder element (1210) has two opposing sides (1220a, 1220b) extending from an inner radial edge of the undercut shoulder element (1210) to an outer radial edge of the undercut shoulder element (1210), where the opposing sides form an acute angle (y) relative to each other, where at least one abutment (1230a, 1230b) extends out tangentially from the opposing sides in connection to the outer radial edge of the undercut shoulder element (1210).

27. The tool holder (1200) according to claim 26, where a length (D3) of the abutments (1230a, 1230b) in the radial direction (R) is at least 1 mm.

28. Surface processing equipment (100) comprising a tool holder (1200) according to any of claims 26-27.

29. A method for producing an abrasive tool (200), the method comprising providing (Sa1 ) material for a carrier plate (310) extending in a plane (P), where the carrier plate (310) is arranged to support one or more abrasive elements (210) on an outer face (315) of the carrier plate (310), forming (Sa2) two sides (220a, 220b) that extend out from an inner face of the carrier plate (310) in a direction transversal to the plane (P), where the two sides (220a, 220b) are separated from each other and form an acute angle (a) relative to each other in the plane (P),where an apex of the acute angle (a) between the sides (220a, 220b) points towards an inner radial edge (I) of the abrasive tool (200) and away from an outer radial edge (O) of the abrasive tool (200), where at least one of the two sides (220a, 220b) extends towards the outer radial edge (O) of the abrasive tool (200) up to a distance (D1 ) from the outer radial edge (O).

30. The method according to claim 29, where the carrier plate (310) and the sides (220a, 220b) are formed in a metal material.

31. The method according to claim 30, comprising forming (Sa21) the two sides (220a, 220b) by bending the carrier plate material along lines angled by the acute angle (y) relative to each other.

32. The method according to any of claims 30 or 31 , comprising cutting (Sa11 ) the material for the carrier plate out from a piece of sheet metal.

33. The method according to claim 29, where the carrier plate (310) and the sides (220a, 220b) are formed in a plastic material.

34. The method according to claim 33, comprising forming (Sa22) the two sides (220a, 220b) and the carrier plate (310) by molding the plastic material.

35. The method according to any of claims 29-34, comprising attaching (Sa3) one or more abrasive elements (210) onto the outer face (315) of the carrier plate (310).

36. A method for processing a concrete or stone surface (101 ), the method comprising, providing (Sb1) surface processing equipment (100), assembling (Sb2) at least one tool holder (120) according to any of claims 13- 24 onto the surface processing equipment (100), attaching (Sb3) one or more abrasive tools according to any of claims 1 -11 onto the at least one tool holder (120), and processing (Sb4) the concrete or stone surface (101 ) by the surface processing equipment (100).

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