GRINDING ELEMENT FOR USE IN ROTARY GRINDING OR POLISHING TOOLS

Abstract

Provided is a grinding element for use in rotary grinding or polishing tools used for grinding or polishing surfaces, and of the type comprising an elongate profile rail, including an abrasive cloth and support brushes. The abrasive cloth and the support brushes are mounted in or on the profile rail, such that the abrasive cloth is supported by the support brushes on its inactive side. The abrasive cloth outside the profile rail has a height in the vertical direction and a length in the longitudinal direction. The support brushes and the abrasive cloth have different heights, a support brush height and an abrasive cloth height, respectively, from the profile rail, such that the abrasive cloth is terminated by an outer exposed edge area extending beyond the top of the support brushes and a short distance down along the outer exposed end portions of the support brushes.

Claims

1. A grinding element for use in rotary grinding or polishing tools used for grinding or polishing surfaces and of a type comprising an elongate profile rail and an abrasive cloth and support brushes, and wherein the abrasive cloth and the support brushes are mounted in or on the profile rail, such that the abrasive cloth on its inactive side is supported by the support brushes, wherein the abrasive cloth outside the profile rail has a height of the abrasive cloth in the vertical direction and a cloth length in the longitudinal direction, wherein the support brushes and the abrasive cloth have different heights, a support brush height and an abrasive cloth height, respectively, from the profile rail, such that the abrasive cloth is terminated by an outer exposed edge area extending beyond the top of the support brushes as the height of the cloth exceeds the height of the support brushes and a short distance down along the outer exposed end portions of the support brushes, which outer exposed edge area, when in use, forms an active area of an active side of the abrasive cloth, wherein the abrasive material is applied only to the active area of the abrasive cloth, which abrasive material includes particles, which abrasive cloth is cut from an outer exposed edge of the cloth against the profile rail in a direction parallel to the vertical direction in order to form slats, and which particles are arranged in adjacent rows, wherein the particles of the abrasive material in a row are arranged with the particles offset relative to the particles in adjacent rows, and wherein the particles in the adjacent rows are spaced apart, such that the abrasive particles overlap in the longitudinal direction of the abrasive cloth.

2. The grinding element according to claim 1, wherein the adjacent rows are arranged at an angle different from 0° with respect to the vertical direction.

3. The grinding element according to claim 1, wherein the adjacent rows are arranged with their orientation in the longitudinal direction.

4. The grinding element according to claim 1, wherein the particles have an extension in the orientation of the row, which is greater than the spacing between the particles in the adjacent rows.

5. The grinding element according to claim 1, wherein the abrasive material is a super-abrasive material, which consists of the particles and a powder of diamonds, or similar materials.

6. The grinding element according to claim 1, wherein the active area constitutes between ¼ and ½ of the height of the abrasive cloth.

7. An abrasive element according to claim 1, wherein the abrasive canvas height of the abrasive canvas is between 20 mm and 80 mm.

8. The grinding element according to claim 1, wherein the abrasive material is made to adhere to the abrasive canvas in the active area with a binder, which bonds the particles to the abrasive cloth.

9. The grinding element according to claim 1, wherein the abrasive material is provided on a second cloth, which second cloth is mounted in the active area of the abrasive cloth.

10. The grinding element according to claim 1, wherein the flexibility of the abrasive cloth in an area between the active area and the profile rail is greater than the flexibility of the abrasive cloth in the active area.

11. The grinding element according to claim 6, wherein the active area constitutes about a third of the height of the abrasive cloth.

12. An abrasive element according to claim 7, wherein the abrasive canvas height of the abrasive canvas is about 40 mm.

Description

BRIEF DESCRIPTION

[0076] Some of the embodiments will be described in detail, with references to the following Figures, wherein like designations denote like members, wherein:

[0077] FIG. 1 is a sideview of a known grinding element showing the support brushes and the inactive side of the abrasive cloth;

[0078] FIG. 2 is a sideview of the grinding element in FIG. 1 showing the active side of the abrasive cloth;

[0079] FIG. 3 is an isometric view of the grinding element shown in FIG. 1 showing the support brushes and the active side of the abrasive cloth;

[0080] FIG. 4 is an isometric view of the device shown in FIG. 1, which is a cross-section perpendicular to the longitudinal direction of the grinding element being used against a surface, wherein the support brushes push the active area of the abrasive cloth against the surface;

[0081] FIG. 5 is an image corresponding to the section in FIG. 2 of an abrasive cloth for a grinding element according to embodiments of the present invention;

[0082] FIG. 6 is a schematic diagram of an enlarged view of the abrasive cloth shown in FIG. 5;

[0083] FIG. 7 is a schematic diagram illustrating a surface machined with a grinding element according to conventional art; and

[0084] FIG. 8 is an illustration corresponding to FIG. 7, wherein a surface is machined with a grinding element according to embodiments of the present invention.

DETAILED DESCRIPTION

[0085] FIGS. 1-4 show the basic design of a conventional art grinding element 1, as disclosed in WO 2011/110176. This design shares the design of a grinding element 1 according to embodiments of the present invention. The difference lies in the way, in which the abrasive particles are arranged on the abrasive cloth. Thus, the grinding element 1 according to embodiments of the invention will be explained with reference to the explanation of the known grinding element. The novel features of embodiments of the invention will be explained in more detail with reference to FIGS. 5-8.

[0086] FIG. 1 shows a grinding element 1 secured in a profile rail 2, which is intended for use in a grinding or polishing tool or machine. The profile rail 2 is elongate, and thus the grinding element 1 has a natural longitudinal direction 3.

[0087] An abrasive cloth 4 is mounted in the profile rail 2, as are support brushes 5. The abrasive cloth 4 is provided with slats 6.

[0088] In this specific embodiment, the profile rail 2 limits the risk of the abrasive cloth 4 and the support brushes 5 being extracted from the profile rail. The abrasive cloth 4 and the support brushes 5 ascend or radiate substantially in the same vertical direction 7 within a narrow angle from the mounting area of the profile rail 2 and in a vertical direction 7.

[0089] Opposite the profile rail 2, the abrasive cloth 4 terminates at an edge of the cloth 8, and the distance between the edge of the cloth 8 and the profile strip 2 defines the height of the cloth 9.

[0090] Opposite the profile strip 2, the support brushes 5 are terminated in a support brush extremity 10, and the distance between the support brush extremity 10 and the profile strip 2 defines the height 11 of the support brush.

[0091] Similarly, the abrasive cloth length 12 is defined as the extension of the abrasive cloth 4 in the longitudinal direction 3, and the support brush length 13 is defined as the extension of the support brushes 5 in the longitudinal direction 3.

[0092] In the embodiment shown, the abrasive cloth 4 is realized with a plurality of slats 6, which in the specific embodiment have roughly the same length 14. However, nothing stands in the way of varying the slat length 14.

[0093] In the embodiment shown, the brush length 13 exceeds the canvas length 12, and there is a plurality of bristles per slat length 14.

[0094] In the embodiment shown, the height 9 of the cloth exceeds the height 11 of the support brush.

[0095] As shown, the inactive side 15 of the abrasive cloth 4 faces the support brushes 5.

[0096] FIG. 2 shows the same grinding element 1 as in FIG. 1, but from a different side, wherein the active side 16 of the abrasive cloth 4 appears.

[0097] The active side 16 of the abrasive cloth 4 has an active area 17 (marked as - - - ), which is coated with an abrasive material 18. The active area 17 is an area at an outer exposed edge area 19 (marked as . . . ) of the abrasive cloth 4 from the edge of the abrasive cloth 8 toward the profile rail 2. It is immaterial whether the outer exposed edge area 19 has a height, which is greater than the height of the active area 17. The important thing is that the two areas 17, 19 have a certain overlap.

[0098] In the embodiment shown and illustrated in the section of the figure, the abrasive material 18 is provided as a super-abrasive material 20, which consists of diamonds 21 in the form of particles 22. Also illustrated here is a powder 23, which may optionally be used with the particles 22. Here, the abrasive material 18 is provided on a second cloth 24, which furthermore is mounted in the active area 17 of the abrasive cloth 4.

[0099] In the specific embodiment, the second cloth 24 is glued to the abrasive cloth 4.

[0100] In the embodiment shown, the abrasive material 18 on the second cloth 24 is cut similarly to the slats 6.

[0101] It can be seen here that the particles 22 are placed in rows 26. It is quite customary in commercially available abrasive canvases of this type for the particles to be placed in adjacent rows on a canvas. The particles 22 in every other row 26 are placed next to one another, as seen in the longitudinal direction 3. The particles 22 in the intermediate rows 26 are located offset next to the spaces. Thus, the rows 26 of particles 22 are oriented parallel to the vertical direction 7. It can also be seen that the cut-out is done parallel to the vertical direction 7 in the spaces 30 between the rows 26. In these spaces 30, the particles 22 do not overlap, such that the spaces 30 in the longitudinal direction 3 of the abrasive cloth have no abrasive material. This gives rise to abraded grooves, in that areas on the surface 25 (see FIGS. 3 and 4), which are abraded with the grinding element 1, will not be coated by the particles 22.

[0102] FIG. 3 is an isometric view of the grinding element 1 showing the support brushes 5 and the active side 16 of the abrasive cloth 4.

[0103] The extremity of the support brush 10 rests or acts on a surface 25, which surface 25 also interacts here with the inactive side 15 of the abrasive cloth 4.

[0104] The abrasive cloth 4 substantially has inner and outer flexibility, wherein the outer flexibility is associated with the active area 17 of the abrasive cloth 4, and the inner flexibility is associated with the area between the active area 17 and the profile rail 2.

[0105] FIG. 4 is an isometric view of the grinding element 1, which is a cross-section perpendicular to the longitudinal direction 3 of the grinding element 1, in use, or acting with the active side 16 of the abrasive cloth 4 facing the surface 25, wherein the support brushes 5 push on the inactive side 15 of the abrasive cloth 4, such that the active area 17 of the abrasive cloth 4 acts or works on the surface 25.

[0106] FIG. 5 shows a section of an abrasive cloth 4 for a grinding element 9 according to embodiments of the present invention. The device shown in FIG. 5 corresponds to the section in FIG. 2 and thus illustrates the abrasive cloth 16, upon which a second canvas 24 is arranged, and in which the abrasive material 18 is provided.

[0107] The abrasive material 18 is provided in the form of particles 22, which are arranged in rows 26. The rows 26 are arranged parallel to the longitudinal direction 3 of the abrasive cloth, and thus perpendicular to the vertical direction 7 of the abrasive cloth. The abrasive rows have a direction 28 at an angle 27 with respect to the vertical direction 7

[0108] The extension 30 of the particles 22 is in the direction of the row 28, and is greater than the spacing 29 between the particles 22 in the adjacent rows 26. Furthermore, the particles are arranged offset relative to one another in the rows 26. In this way, an overlap of abrasive particles over the whole longitudinal direction 3 of the abrasive cloth is obtained, such that any area of a surface 25 being machined will be coated with particles 22 from one or the other row 26.

[0109] FIG. 6 has an enlarged section showing the abrasive particles 22 arranged in rows 26. It also illustrates more clearly that the extent 30 of the particles is greater than the distance 29 between the particles 22.

[0110] In FIG. 6, the particles are shown with a substantially circular shape. Alternatively, however, the particles 22 may have a different shape.

[0111] FIG. 7 illustrates a surface 25 abraded with a conventional grinding element of the type shown in FIG. 1. It can be seen that the surface 25 is provided with abraded grooves or depressions 32. These are created in areas next to each row 26 of particles 22, which in the known design are oriented in the vertical direction 7 of the abrasive cloth.

[0112] Between the depressions 32, there are areas with a flat surface 31. This flat surface 31 is an untreated flat surface, which appears without roughness. It may be smooth, which makes it difficult for varnish or other coating to adhere to the plane 31 of the flat surface 25. These flat surfaces 31 will also give rise to undesired reflections and glare from incident light, in that no diffusion occurs from the flat surfaces 31.

[0113] FIG. 8 illustrates a surface 25 machined with a grinding element according to embodiments of the present invention. It can be seen here that the whole top surface of the plane 25 is machined by grinding elements, such that a series of adjacent abrasive grooves or depressions 32 are formed. Between the adjacent abrasive grooves or depressions 32, peaks 33 are provided, which are approximately sharp.

[0114] With this abrasion, roughness is obtained over the whole top surface of the plane 25, which increases the chance that varnish or other coating will adhere. Furthermore, the rough surface will diffusely reflect incident light. Thus, glare and reflection will largely be avoided with a plane 25, as illustrated in FIG. 8.

[0115] Experiments have been conducted with grinding elements of the known type, as illustrated in FIG. 1, and with grinding elements of the novel type, as illustrated in FIG. 5. In this case, experiments were conducted with gelcoat and carbon.

[0116] With a grain size of 200, it was found with gelcoat, that a grinding element according to embodiments of the invention yields a roughness parameter (Ra) of 2.7, and with the known system, an RA of 2.5. Similarly, with carbon and a grain size of 200, an RA of 2.8 with a grinding element according to embodiments of the invention, and an RA of 2.4 with the known grinding element were measured.

[0117] In addition, tests with a grain size of 120 have revealed an RA value of 4.4 and 3.6, respectively, for the grinding element according to embodiments of the invention, over the previous one on gelcoat. Similarly, with a grain size of 120, an RA of 3.4 and 2.9, respectively, was measured in a carbon for a grinding element according to embodiments of the invention as compared with the previous one.

[0118] In other words, there is evidence of improved roughness with both grain size 120 and grain size 200. For a grain size of 120, the roughness value thus increased by 22 percent.

[0119] For customers, this could mean a significant improvement in the adhesion and reduced reflection, as well as in the grinding rate and the service life of the grinding elements.

[0120] Although the present invention has been disclosed in the form of preferred embodiments and variations thereon, it will be understood that numerous additional modifications and variations could be made thereto without departing from the scope of the invention.

[0121] For the sake of clarity, it is to be understood that the use of “a” or “an” throughout this application does not exclude a plurality, and “comprising” does not exclude other steps or elements. The mention of a “unit” or a “module” does not preclude the use of more than one unit or module.