Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B24—GRINDING; POLISHING
  • B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
  • B24B7/00—Machines or devices designed for grinding plane surfaces on work, including polishing plane glass surfaces; Accessories therefor
  • B24B7/10—Single-purpose machines or devices
  • B24B7/18—Single-purpose machines or devices for grinding floorings, walls, ceilings or the like
  • B24B7/186—Single-purpose machines or devices for grinding floorings, walls, ceilings or the like with disc-type tools
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B24—GRINDING; POLISHING
  • B24D—TOOLS FOR GRINDING, BUFFING OR SHARPENING
  • B24D7/00—Bonded abrasive wheels, or wheels with inserted abrasive blocks, designed for acting otherwise than only by their periphery, e.g. by the front face; Bushings or mountings therefor
  • B24D7/06—Bonded abrasive wheels, or wheels with inserted abrasive blocks, designed for acting otherwise than only by their periphery, e.g. by the front face; Bushings or mountings therefor with inserted abrasive blocks, e.g. segmental
  • B24D7/066—Grinding blocks; their mountings or supports
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B24—GRINDING; POLISHING
  • B24D—TOOLS FOR GRINDING, BUFFING OR SHARPENING
  • B24D18/00—Manufacture of grinding tools or other grinding devices, e.g. wheels, not otherwise provided for
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B24—GRINDING; POLISHING
  • B24D—TOOLS FOR GRINDING, BUFFING OR SHARPENING
  • B24D18/00—Manufacture of grinding tools or other grinding devices, e.g. wheels, not otherwise provided for
  • B24D18/0009—Manufacture of grinding tools or other grinding devices, e.g. wheels, not otherwise provided for using moulds or presses
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B24—GRINDING; POLISHING
  • B24D—TOOLS FOR GRINDING, BUFFING OR SHARPENING
  • B24D7/00—Bonded abrasive wheels, or wheels with inserted abrasive blocks, designed for acting otherwise than only by their periphery, e.g. by the front face; Bushings or mountings therefor

Definitions

• the present disclosure relates to floor grinders and abrasive tools for processing concrete surfaces.
• abrasive tools for use in grinding and polishing concrete surfaces, systems for abrasive processing of concrete surfaces, and manufacturing methods for producing abrasive tools.
• 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.
• 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.
• the abrasive tool is robust such that it does not break during use. At the same time, it is desired to reduce the cost of the tools in order to provide a cost efficient concrete surface processing operation.
• the abrasive tool comprises an attachment plate arranged to releasably attach to a tool holder of the floor grinder.
• the abrasive tool also comprises an abrasive tool section at least partly formed in an abrasive material.
• the attachment plate comprises a supporting surface at least partly formed in a plastic material, where the supporting surface is configured to align with a corresponding surface on the abrasive tool section.
• the attachment plate and the abrasive tool section are held together by one or more welds. This way a cost efficient yet durable and high performing abrasive tool is provided.
• the abrasive tool can be manufactured in several different grits simply by changing the properties of the abrasive tool section.
• the one or more welds comprises an ultrasonic weld.
• Ultrasonic welds are particularly suitable for manufacturing this type of abrasive tool.
• a plurality of protrusions extends from the supporting surface of the attachment plate along a normal vector of the supporting surface. These protrusions facilitate ultrasonic welding of the attachment plate to the abrasive tool section.
• the attachment plate comprises a rim portion extending along a perimeter of the supporting surface.
• the rim portion is arranged to hold the abrasive tool section laterally with respect to the normal vector of the supporting surface.
• the rim portion further increases the mechanical strength of the abrasive tool, and in particular improves the resilience against impact from the side.
• the abrasive tool section comprises a planar support element and a plurality of abrasive elements arranged protruding from the planar support element in a direction normal to the supporting surface. Since the plurality of abrasive elements are integrally formed with the planar support element, mechanical strength is improved. Also, the abrasive tool section can be formed in one piece, which simplifies manufacturing. According to aspects, the abrasive tool section comprises an abrasive material embedded in an at least partly plastic material. This plastic material embedding allows the abrasive tool section to be ultrasonically welded to another plastic component, such as the attachment plate.
• the plastic material is phenolic novolac, which comprises suitable properties for the present application.
• the abrasive tool section is associated with a grit between 30-200 and where the abrasive tool section comprises a relative volume percentage of silicon carbide between 10-20%, and preferably about 15%. Also, the relative volume percentage of talc is optionally between 5-15%, and preferably about 10%. This increases the grinding efficiency of the abrasive tool, and at the same time provides a good wear resistance.
• the abrasive tool further comprises a cage part comprising apertures arranged to receive the abrasive elements extending from the planar support element of the abrasive tool section.
• This cage part adds to the structural integrity of the abrasive tool and further increases the mechanical strength of the assembly, which is an advantage.
• the cage part is at least partly formed in a plastic material and the cage part is welded to the attachment plate and/or to the abrasive tool section, thereby holding the attachment plate and the abrasive tool section together by the one or more welds. It is noted that the cage part may be used to hold the abrasive tool section in place without any weld of other form of joining between the abrasive tool section and the attachment plate or cage part parts.
• the cage part comprises one or more ridges arranged facing in the direction of the attachment plate, where the ridges are configured to facilitate ultrasonic welding of the cage part to the attachment plate and/or to the abrasive tool section.
• the ridges facilitate ultrasonic welding of the cage part to the attachment plate.
• Figures 1A-B illustrate an example floor grinder
• Figures 2-3 show an abrasive grinding tool for a floor grinder
• Figures 4A-B illustrates an attachment plate for an abrasive tool
• Figures 5A-C illustrates an abrasive tool section for an abrasive tool
• Figures 6A-C illustrates a cage part for an abrasive tool
• Figure 7 is a flow chart illustrating a manufacturing method; and Figures 8-10 show alternative abrasive grinding tools.
• Figures 1A and 1 B illustrate an example floor grinder 100 for processing a concrete surface 101.
• the 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 machine 100 can be used to grind and to polish concrete 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 1500 indicates a fine grit.
• the techniques disclosed herein may be used with advantage for a wide variety of different grit seize, ranging from, e.g., 30 to about 3000.
• abrasive tools are often a substantial part of the overall cost of concrete surface processing. It is therefore desired to produce abrasive tools in a cost efficient manner. Flowever, the abrasive tools still need to meet requirements on robustness and durability. A tool which breaks during use leads to unwanted delay and may also damage both the concrete surface and the floor grinder.
• the abrasive tools disclosed herein are preferably but not necessarily formed in a plastic material.
• Plastics are a wide range of synthetic or semi-synthetic materials, that use polymers as a main ingredient. The plasticity during production makes it possible for plastic to be molded, extruded, or pressed into solid objects of various shapes, making it an adaptable material for many different uses.
• the components disclosed herein are suitable for injection molding, which is the preferred method of manufacturing the components. However, other methods for producing the components of the tools disclosed herein are of course also possible.
• Figure 2 illustrates an abrasive tool 200 for use, e.g., with the floor grinder 100.
• Figure 3 shows an exploded view of the abrasive tool 200.
• the abrasive tool 200 comprises an attachment plate 230 arranged to releasably attach to a tool holder 120 of the floor grinder 100 by angled wings 310.
• This mechanism comprises opposing and angled wings 310 for attaching the attachment plate of the abrasive tool 200 to the tool holder 120 is previously known and will therefore not be discussed in more detail herein.
• the abrasive tool 200 comprises an abrasive tool section 220 at least partly formed in an abrasive material.
• This abrasive material preferably comprises diamond granules held in a supporting matrix of, e.g., phenolic novolac, although other binding matrix materials can also be used.
• the abrasive tool section 220 comprises two or more protruding abrasive elements (Figure 2 shows six such protruding elements) which are brought into rotating contact with the concrete surface by the tool holder 120, whereupon the concrete surface is ground or polished, depending on the grit size of the abrasive material.
• Each of the components 210, 220, and 230 in Figure 3 has a front side and a back side, where the front side of each component faces in the direction of the normal vector N indicated by the arrow in Figure 3.
• the front side of each component faces in the direction of the concrete surface to be processed when the tool is in use, and the back side faces towards the tool holder 120 on the machine 100.
• the attachment plate 230 comprises a supporting surface 235 at least partly formed in a plastic material.
• This supporting surface 235 is configured to align with a corresponding back surface 510 (shown in Figure 5B) on the abrasive tool section 220.
• the front surface of the attachment plate 230 i.e., the surface facing away from the tool holder side of the attachment plate, may be arranged parallel to the back surface of the abrasive tool section 220, such that the two surfaces make contact with each other in a mating position.
• the attachment plate 230 and the abrasive tool section 220 are held together by one or more welds.
• These welds are preferably ultrasonic welds which can be formed in a cost efficient manner during assembly, and which provide a sufficient bond strength for the abrasive tool.
• other types of welds are also possible, such as laser welds, vibration welds, or simply welds formed by melting plastic components together to form welded sections.
• the abrasive tool section 220 is welded directly to the attachment plate.
• the abrasive tool section 220 is held in position by a cage part 210 which is welded to the attachment plate 230.
• the abrasive tool section 220 does not necessarily need to be welded or otherwise directly attached to any other component of the abrasive tool 200, although this is certainly an option also.
• the abrasive tool section 220 is first welded to the attachment plate 230, whereupon the cage part 210 is welded to the attachment plate to reinforce the abrasive tool structure.
• Figure 4A shows a front side view of the attachment plate 230
• Figure 4B shows a back side view of the attachment plate 230, i.e., the side facing the tool holder 120.
• the front side of the attachment plate 230 faces in the direction of the concrete surface during a grinding or polishing operation, while the back side of the attachment plate faces towards the tool holder 120 on the floor grinding machine 100.
• a plurality of protrusions optionally extends from the supporting surface 235 of the attachment plate 230 along the normal vector N of the supporting surface. These protrusions facilitate ultrasonic welding of the abrasive tool section 220 to the attachment plate 230.
• the attachment plate 230 optionally also comprises a rim portion 320 as shown in Figure 4A extending along a perimeter of the supporting surface 235.
• This rim portion 320 is arranged to hold the abrasive tool section 220 laterally with respect to the normal vector N of the supporting surface 235 when the supporting surface 235 and the corresponding surface 510 are in contact with each other in the mated position.
• This rim portion 320 further increases the mechanical integrity of the abrasive tool 200 since the tool is now able to withstand a higher degree of lateral forces.
• the opposing and angled wings 310 configured for mounting the attachment plate to the tool holder 120 are located at an offset O from the edge of the attachment plate 230. Thus, the supporting surface 235 extends beyond the opposing and angled wings 310.
• Figures 5A-C show views of the abrasive tool section 220;
• Figure 5A shows a front side view
• Figure 5B shows a back side view
• Figure 5C shows a side view.
• the front side is the side facing the concrete surface during processing
• the back side is the side facing the tool holder.
• the abrasive tool section 220 illustrated in Figures 5A-C comprises a planar support element 530 and a plurality of abrasive elements 520 arranged protruding from the planar support element 530 in a direction D normal to the supporting surface 510.
• the abrasive tool section is integrally formed in one piece, which allows for a cost efficient molding process for producing the abrasive tool section in one step.
• abrasive elements 520 By integrally forming the abrasive elements together with the planar support element an increased mechanical strength is also obtained compared to if separate abrasive elements would have been comprised in the abrasive tool section 220.
• the abrasive tool section 220 comprises an abrasive material which is preferably embedded in an at least partly plastic material. This allows the abrasive tool section 220 to be ultrasonically welded directly to the attachment plate 230, which is an advantage since it enables a cost efficient assembly. However, it is noted that the abrasive tool section 220 may also be attached by other means of the attachment plate 230, e.g., by means of the cage part 210 which will be discussed below in connection to Figures 6A-C.
• the abrasive tool section may be at least party formed in the plastic material phenolic novolac, which also contributes to the mechanical integrity and strength of the abrasive tool section.
• compositions can be used with advantage for various grit sizes.
• the table below illustrates a number of examples which have been found to yield favorable results in terms of both concrete processing efficiency, wear rate, and mechanical resilience and endurance.
• the example grit sizes range from 30 grit which is a relatively coarse grit used for grinding operations, to a very fine grit of 3000 which is suitable for polishing operations.
• the percentage values given are volume percentages.
• the diamond concentration in the rightmost column is given in carats per cm 3 . It is understood that the relative percentages below are approximate values, and that a similar technical effect can be achieved by altering the relative percentages somewhat.
• the silicon carbide (SiC) content of about 15 % in the course grit variants 30- 200 together with the reduced talc content of about 10 % provides for an increased wear resistance at the same time as an improved grinding efficiency is obtained.
• the abrasive tool section 220 comprises any of talc, rubber, silicon carbide, green chromium oxide and diamond granules.
• the abrasive tool section 220 is optionally associated with a grit between 30-200 in which case the abrasive tool section advantageously comprises a relative volume percentage of silicon carbide between 10-20%, and preferably about 15%.
• the abrasive tool section 220 optionally comprises a relative volume percentage of talc between 5-15%, and preferably about 10%.
• FIGS 6A-C illustrate an optional cage part 210 which can be used to reinforce the mechanical structure of the abrasive tool 200.
• This cage part comprises apertures 610 arranged to receive the abrasive elements 520 extending from the planar support element 530 of the abrasive tool section 220.
• the cage part is then attached to the attachment plate 230 and/or to the abrasive tool section 220 in order to hold the structure together more robustly.
• the cage part 210 may be at least partly formed in a plastic material.
• the cage part 210 can be ultrasonically welded to the attachment plate 230 and/or to the abrasive tool section 220, thereby holding the attachment plate 230 and the abrasive tool section 220 together by the one or more welds.
• the abrasive tool 200 may comprise one or more ridges 620 extending from the back side of the cage part in the direction of the attachment plate 230. These ridges are configured to facilitate ultrasonic welding of the cage part 210 to the attachment plate 230 and/or to the abrasive tool section 220.
• the cage part 210 comprises at least two apertures, and preferably six apertures as shown in Figures 6A and 6B.
• Each aperture is configured to receive one abrasive element and has a shape matched to that element, e.g., one of the abrasive elements 520 arranged protruding from the planar support element 530 on the abrasive tool section 220 as shown in Figure 5A.
• the apertures in Figures 6A and 6B are arranged surrounding a central solid portion 630 of the cage part 210.
• the apertures constitute at least half of a total surface area of the cage part 210.
• the cage part 210 is shaped as a frame to hold the abrasive tool section in place, and to reinforce the structure, but does not comprise a lot of plastic material.
• the primary function of the cage part is to keep the abrasive tool section 220 pressed in position against the attachment plate 230.
• the apertures of the cage part 210 are substantially polygon shaped with at least three sides.
• the cage part 210 illustrated in Figure 6A and 6B has two three-sided polygon-shaped apertures and four four-sided polygon-shaped apertures.
• the cage part 210 may, as mentioned above, further comprise a centrally positioned solid portion 630, as shown in Figure 6A.
• any of the parts 210, 220, 230 may be formed by an injection molding process in a cost efficient manner.
• Figure 7 illustrates a method for producing an abrasive tool 200.
• the method comprises forming S1 at least an attachment plate 230 and an abrasive tool section 220 at least partly from a plastic material, preferably by an injection molding process.
• the method optionally also comprises forming the cage part 210 discussed above.
• the method further comprises assembling S2 the attachment plate 230 and the abrasive tool section 220 (and optionally also the cage part 210) and attaching the components in fixed relation to each other by means of one or more welds, where the one or more welds preferably comprise one or more ultra-sonic welds.
• FIGS 8A-B illustrate an abrasive grinding tool 800 comprising an attachment plate 230 and an abrasive tool section 220.
• the abrasive tool section 220 is the same as described above, i.e., comprises the same set of optional technical features and advantages.
• the attachment plate 230 is integrally formed with a rim portion 810 which extends along a perimeter of the attachment plate 230 as shown in Figure 8A.
• the rim portion 810 is shaped to match the shape of the abrasive tool section 220, such that the abrasive tool section can be snugly received inside the rim portion 810 of the attachment plate 230.
• the rim portion is arranged to be deformed by melted during assembly of the abrasive tool 800, such that a protuberance is formed which holds the abrasive tool section 220 in position relative to the attachment plate 230.
• FIGs 9A-B illustrate another example of how an abrasive tool 900 can be assembled to obtain a cost efficient tool.
• This abrasive tool 900 comprises an attachment plate 230 where holes 910 have been formed along a circumferential flange or rim portion 920 of the attachment plate 230.
• An abrasive tool section 220 according to the above discussion is arranged on the attachment plate 230 and held in position by a frame 930 which partly overlaps the abrasive tool section 220 along its periphery as shown in Figure 9A.
• the frame 930 comprises pins 940 arranged to be received in the holes 910 when the frame 930 is in mating position with the attachment plate 230, as shown in Figure 9B.
• the pins 940 can be secured in the holes by, e.g., melting or gluing.
• FIG 10 shows yet another example of an abrasive tool 1000.
• This tool 1000 also comprises an attachment plate 230.
• This attachment plate has through- holes 1010 for receiving corresponding pins 1020 of a holding plate 1030, which has a shape matched to the abrasive tool section 220, i.e., the holding plate 1030 generally has a shape matched to the plurality of abrasive elements arranged protruding from the planar support element of the abrasive tool section 220, such that the holding plate fits in-between the abrasive elements.
• the through holes 1010 formed in the attachment plate are matched with corresponding through-holes formed in the abrasive tool section 220.
• the pins 1020 can be melted or glued in the mating position, i.e., when the pins are received in the holes of the attachment plate, in order to hold the abrasive tool section 220 in position relative to the attachment plate.
• the attachment plate may optionally comprise the rim portion 810 discussed above in connection to Figure 8A, to hold the abrasive tool section in lateral position.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Manufacturing & Machinery (AREA)
• Polishing Bodies And Polishing Tools (AREA)

Priority Applications (4)

Applications Claiming Priority (2)

Publications (1)

Family

ID=83154504

Family Applications (1)

Country Status (6)

Citations (6)

• 2021
  • 2021-03-03 SE SE2150241A patent/SE544763C2/en unknown
• 2022
  • 2022-02-07 US US18/280,055 patent/US20240149385A1/en active Pending
  • 2022-02-07 EP EP22763680.0A patent/EP4301553A1/en active Pending
  • 2022-02-07 CN CN202280018066.6A patent/CN116963872A/zh active Pending
  • 2022-02-07 AU AU2022231625A patent/AU2022231625A1/en active Pending
  • 2022-02-07 WO PCT/SE2022/050129 patent/WO2022186745A1/en active Application Filing

Patent Citations (6)

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