Grinding disc

Abstract

Embodiments described herein generally relate to a grinding disc is being rotatably drivable around an axis of rotation. The grinding disc has a front side as well as a rear side facing away from the front side. The grinding disc further includes a multi-layered circular grinding blank packet with a plurality of circular grinding blanks. The grinding blanks are flatly stacked over each other along the axis of rotation and in which each grinding blank includes a central through opening. The central through openings form together a recess of the circular grinding blank packet. Wherein the grinding disc has a backing plate, which is arranged in the recess, and the circular grinding blanks each are fixed individually to the backing plate.

Claims

1. A grinding disc being rotatably drivable around an axis of rotation and having a front side and a rear side facing away from the front side, the grinding disc comprises: a multi-layered circular grinding blank packet with a plurality of circular grinding blanks, each having an uninterrupted continuous planar surface, the circular grinding blanks being stacked over each other along the axis of rotation, each of the circular grinding blanks having a central through opening, wherein the central through openings form together a recess of the circular grinding blank packet, the recess defining a stepped inner profile in which each succeeding blank defines a different inner diameter, and wherein that the grinding disc has a backing plate arranged in the recess so that more than one of the circular grinding blanks are fixed individually to the backing plate along a flat support surface of each grinding blank which is in contact with a stepped opposing surface of said backing plate.

2. The grinding disc according to claim 1, wherein starting from the front side and extending to the rear side the central through openings of the circular grinding blanks increase in size at least along a portion of the circular grinding blank packet extending parallel to the axis of rotation.

3. The grinding disc according to claim 1, wherein starting from the rear side and extending to the front side the central through openings of the circular grinding blanks increase in size at least along a portion of the circular grinding blank packet extending parallel to the axis of rotation.

4. The grinding disc according to claim 1, wherein the grinding blanks each further include a central annular portion fixed to an attachment face of the backing plate, said attachment face being arranged parallel to the front side.

5. The grinding disc according to claim 1, wherein the backing plate is poured into the recess.

6. The grinding disc according to claim 1, wherein a threaded element having an internal thread for attaching the grinding disc to a drive machine is arranged in the backing plate.

7. The grinding disc according to claim 1, wherein the through openings of the circular grinding blanks comprise a cross-section deviating from a circle.

8. The grinding disc according to claim 1, wherein the circular grinding blanks each comprise an outer circumferential face, wherein the outer circumferential face of all circular grinding blanks are identical in shape, size and alignment.

9. The grinding disc according to claim 1, wherein the circular grinding blanks each comprise an outer circumferential face, wherein the outer circumferential faces when seen in the cross-section of the grinding disc are each arranged at an angle between 5 and 85 to the axis of rotation.

10. The grinding disc according to claim 1, wherein an outer circumferential face of each blank comprise a radial recesses.

11. The grinding disc according to claim 1, wherein the grinding disc comprises a support layer on the rear side.

12. The grinding disc according to claim 1, wherein at least a subset of the circular grinding blanks each comprise a grinding layer on a side facing towards the front side of the grinding disc.

13. The grinding disc according to claim 1, wherein at least a subset of the circular grinding blanks each comprise a grinding layer on a side facing towards the rear side of the grinding disc.

14. The grinding disc according to claim 1, wherein at least one of the circular grinding blanks comprises a plurality of segments distributed in circumferential spaced direction, said segments being separated by radially extending recesses.

15. The grinding disc according to claim 9, wherein the outer circumferential faces comprise radial recesses.

16. A grinding disc being rotatably drivable around an axis of rotation and having a front side and a rear side facing away from the front side, the grinding disc comprises: a multi-layered circular grinding blank packet with a plurality of circular grinding blanks, each having an uninterrupted continuous planar surface, the circular grinding blanks are flatly stacked over each other along the axis of rotation, each of the circular grinding blanks having a central through opening, wherein the central through openings form together a recess of the circular grinding blank packet, wherein the central through openings of at least a subset of the circular grinding blanks of the circular grinding blank packet are formed differently-sized, and wherein the grinding disc has a backing plate arranged in the recess so that more than one of the circular grinding blanks are fixed individually to the backing plate along a flat support surface of each grinding blank which is in contact with a stepped opposing surface of said backing plate.

17. A grinding disc being rotatably drivable around an axis of rotation and having a front side and a rear side facing away from the front side, the grinding disc comprises: a multi-layered grinding blank packet with a plurality of grinding blanks, each having an uninterrupted continuous planar surface, the grinding blanks being stacked over each other along the axis of rotation, each of the grinding blanks having a central through opening, wherein the central through openings form together a recess of the grinding blank packet, the recess defining a stepped inner profile in which each succeeding blank defines a different inner diameter, and wherein that the grinding disc has a backing plate arranged in the recess so that more than one of the grinding blanks are fixed individually to the backing plate along a flat support surface of each grinding blank which is in contact with a stepped opposing surface of said backing plate.

18. The grinding disk according to claim 17, said inner profile of each of said plurality of grinding blanks further comprising a circular profile.

19. The grinding disk according to claim 17, said inner profile of each of said plurality of grinding blanks further comprising a polygonal profile defined by an inscribed circle.

20. The grinding disk according to claim 19, said inner polygonal profile further comprising a hexagonal shape.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Preferred embodiments are described in detail in the following using the drawings. Herein, it shows:

(2) FIG. 1 illustrates a top view onto the rear side of a first embodiment of a grinding disc according to the one or more embodiments shown and described herein;

(3) FIG. 2 illustrates a cross-sectional view of the grinding disc of FIG. 1;

(4) FIG. 3 illustrates a perspective view of the grinding blanks packet of the grinding disc of FIG. 1;

(5) FIG. 4 illustrates a perspective view of the grinding blanks packet of FIG. 3 with a threaded nut inserted in the recess;

(6) FIG. 5 illustrates a perspective view of a second embodiment of a grinding blanks packet;

(7) FIG. 6 illustrates a perspective view of a third embodiment of a grinding blanks packet;

(8) FIG. 7 illustrates a top view onto the front side of a second embodiment of a grinding disc according to one or more embodiments shown and described herein;

(9) FIG. 8 illustrates a top view onto the rear side of a third embodiment of a grinding disc according to the one or more embodiments shown and described herein;

(10) FIG. 9 illustrates a cross-sectional view of the grinding disc of FIG. 8;

(11) FIG. 10 illustrates a side view of a fourth embodiment of a grinding blanks packet;

(12) FIG. 11 illustrates a top view onto the front side of a fourth embodiment of a grinding disc according to the one or more embodiments shown and described herein; and

(13) FIG. 12 illustrates a cross-sectional view of the grinding disc of FIG. 11.

DETAILED DESCRIPTION

(14) FIGS. 1 to 4 show a first embodiment of a grinding disc 3 and are described in the following together.

(15) The grinding disc 3 comprises a circular grinding blanks packet 2 with a plurality of individual circular grinding blanks 6. The circular grinding blanks packet 2 is fixed to a backing plate 1, wherein each individual circular grinding blank 6 is directly connected or fixed to the backing plate 1. The grinding disc 3 is rotatably drivable around an axis of rotation D. The grinding disc 3 has a front side 4 for the machining of a workpiece. Furthermore, the grinding disc 3 has a rear side 5 facing away from the front side 4. The individual circular grinding blanks 6 are stacked on top of each other in a flat manner in direction of the axis of rotation D. On the front side 4, a final circular blank 8 is provided, which is part of the multi-layered circular grinding blanks packet 2. The final circular blank 8 is also a circular grinding blank of the circular grinding blanks packet 2. The finish circular blank 8 is, however, optional and can also be omitted. All circular grinding blanks 6 have a flexible supporting substrate and are provided at least on the surface, facing the front side 4, with an abrasive grain coating. The final circular blank 8 can also be provided with an abrasive grain coating or be manufactured from the same material as the circular grinding blanks 6. Thus, the final circular blank 8 as a first circular grinding blank, when seen from the front side 4 of the grinding disc 3, can contribute a major part of the grinding efficiency. Generally, the circular grinding blanks 6 and the final circular blank 8 can also be provided on the surface facing the rear side 5 with an abrasive grain coating.

(16) The circular grinding blanks 6 have central through openings 7 and an uninterrupted continuous planar surface. Also the final circular blank 8 is provided with a central through opening 9. The final circular blank 8 can, however, also be provided continuously flat without central through opening.

(17) The central through openings 7 of the circular grinding blanks 6 are formed in the first embodiment of the grinding disc 3 circular concentrically to the axis of rotation D, wherein the diameter of the central through openings 7, starting from the front side 4 towards the rear side 5, are increasing in size. The through openings 7 form, thus, a central recess 10 in the circular grinding blanks packet 2.

(18) In the recess 10 of the circular grinding blanks packet 2, the backing plate 1 is arranged, on which the circular grinding blanks 6 and the final circular blank 8 are attached. In the shown embodiment, the backing plate 1 is poured into the recess 10. In this case, as shown in FIG. 4, beforehand, a threaded nut 15, by means of which the grinding disc 3 is attachable to a driving tool, is inserted in the recess 10. The space around the threaded nut 15 and within the annular discs can then be filled with a hardening material (synthetic resin, epoxy resin, phenolic resin, polyurethane or any other adhering- or mastic system known to the specialist), which bonds together the circular grinding blanks 6 and the threaded nut 15 after the hardening. Alternatively to the threaded nut 15, also other threaded elements or sleeves can be used. A prerequisite is always the attachability on a driving machine. In a preferred case of an angle grinder, the threaded nut 15 has the advantage of the ability to quickly screw it onto the angle grinder. A common hex nut is already sufficient, to improve the stability of the anchoring in the mastic- or resin system. However, also other geometries, especially with increased surface area (roughened, wings, rim, etc.) are possible. The material of the threaded element can be metal, preferably stainless metal, however also plastics. Of course also a combination of metal thread, imbedded in a plastic ring, etc. is possible.

(19) In the embodiment of FIGS. 1 to 4 for attaching on a driving machine, the backing plate 1 has a central through opening 14. The recess 10 and the backing plate 1 are, thus, formed essentially conical, wherein the cone angle opens towards the rear side 5.

(20) The diameters of the through openings 7 of the individual circular blanks 6 are, furthermore, stepped such that annular portions 11, laying open facing the rear side 5, are formed, by means of which the individual circular blanks 6 are arranged in abutment to step-like formed attachment faces 12 of the backing plate 1 and are attached thereto. Thus, it is ensured, that an as large as possible face of the individual grinding blanks 6 abuts the backing plate 1. Furthermore, the final circular blank 8 has an annular portion 23, laying open facing towards the rear side 5, by means of which the final circular blank 8 is arranged in abutment to an attachment face 24 of the backing plate 1 and is fixed thereto.

(21) The individual circular grinding blanks 6 have, respectively, a circular outer circumferential face 13. The outer circumferential faces 13 of all circular grinding blanks 6 and of the final circular blank 8 have the same diameter so that as a whole a circular cylindrical outer face of the circular grinding blanks packet 2 is achieved for the grinding disc 3.

(22) The recess 10 is essentially formed like a frustum in a stepped manner, wherein the material, which is for the manufacture of the backing plate 1 poured into the recess 10, does not flow or flows only to a small extent between the circular grinding blanks 6 during the pouring. Ideally, the cone angle of an envelope face enclosing the backing plate 10 is approximately 160 to 170 degress, preferably approximately 164 degress. Thus, it is enabled, that the operator can position the grinding disc 3 in different angles on the surface of the to be machined workpiece. In this case, the circular grinding blanks packet 2 can be completely used up as far as possible till the backing plate 1 strikes the workpiece.

(23) FIG. 5 shows a second embodiment of a circular grinding blanks packet 2 of a grinding disc 3. The through openings 7 of the circular grinding blanks 6 are, in this embodiment, not circular in cross-section, but deviate from a circular shape. They are formed in the shape of a hexagonal polygon. The backing plate (not shown here) is formed correspondingly so that an increased rotational security of the circular grinding blanks packet 2 is ensured relative to the backing plate.

(24) FIG. 6 shows a third embodiment of a circular grinding blanks packet 2, wherein for increasing the rotational safety of the circular grinding blanks packet 2 relative to the backing plate 1 (not shown here) recesses 17 extending radially in the individual circular grinding blanks 6 are provided, wherein the circular grinding blank 6, arranged next to the rear side 5, has instead of the recesses 17 radially extending webs 18.

(25) FIG. 7 shows a top view onto a front side 4 of a second embodiment of a grinding disc 3, wherein the outer circumferential faces 13 of the circular grinding blanks 6 have a contour deviating from a circle. In the outer circumferential faces 13 of the circular grinding blanks 6, viewing recesses 19 extending radially inwards, are provided, which enable with the rotationally driven grinding disc 3 a view onto the grinding result.

(26) FIGS. 8 and 9 show a third embodiment of a grinding disc 3, wherein the outer circumferential faces 13 of the circular grinding blanks 6 and of the final circular blank 8, as described in relation to FIGS. 1 to 6, form a circular cylindrical outer circumferential face 20. Additionally to the circular grinding blanks 6 and the final circular blank 8, the grinding disc 3 has a support layer 21 made from a glass fiber fabric with phenolic resin. The support layer 21 has also a through opening 22, which together with the further through openings 7, 9 of the circular grinding blanks 6 and of the final blank 8 form the central recess 10. The backing plate 1 is poured into the recess 10 so that also the disc-like support layer 21 is fixed to the backing plate 1. The through openings 7 of the circular grinding blanks 6 are getting larger starting from the front side 4 to the rear side 5, wherein the through opening 22 of the support layer 21 is smaller than the through opening 7 of the neighboring circular grinding blank 6. Furthermore, the support layer 21 has a smaller outer diameter than the circular grinding blanks 6.

(27) While using the grinding disc 3 and the progressing wear of the circular grinding blanks 6 resulting, in certain circumstances, the lowest or even the lower layers of the circular grinding blanks 6 can slowly bend or fold over. This can be prevented by reinforcement in form of the support layer 21 for the axial support of the circular grinding blanks packet 2.

(28) In a special embodiment, the recess 10 of the grinding blanks packet 2 is not only filled with hardenable material but also the last layer of the circular grinding blanks 6 is coated on the rear side with hardenable material. Thus, the last circular grinding blank 6 is fixed on the rear side additionally to the backing plate 1 and is at the same time reinforced against folding over. Alternatively, the last circular grinding blank 6 can also be substituted by a fiber disc or a disc made from a different harder material, which is more rigid than the circular grinding blank 6 arranged above.

(29) In FIG. 10 a fourth embodiment of a circular grinding blanks packet 2 is shown in a side view. The individual circular grinding blanks 6 have, respectively, a circular outer circumferential face 13, wherein the outer circumferential faces 13 are formed in such a shape and size, that they form a conical outer circumferential envelope face 20 of the circular grinding blanks packet 2. The outer circumferential faces 13 of the circular grinding blanks 6 are arranged with view onto the side view by means of forming an angle relative to the axis of rotation. The angle can be between 5 and 85, especially between 20 and 40 and is, here, shown only exemplary with approximately 30. The optimal angle results, however, from the grinding task, for which the grinding disc 3 should be used.

(30) FIG. 11 shows a top view onto a front side 4 of a fourth embodiment of a grinding disc 3, wherein the outer circumferential faces 13 of the individual grinding blanks 6 and of the two final circular blanks 8 have, respectively, a circular outer circumferential face 13. The outer circumferential faces 13 of all circular grinding blanks 6 and of the final circular blanks 8 have the same outer diameter so that in total a circular cylindrical outer face of the circular grinding blanks packet 2 is achieved. In FIG. 12 the grinding disc 3 according to the fourth embodiment is shown in a side view. It can be seen, that the through openings 7 of the grinding blanks 6 in contrast to the above mentioned embodiments do not, starting from the front side 4 to the rear side 5, increase continuously. Instead, the central through openings 7 of circular grinding blanks 6 and the final circular blanks 8 shown in FIG. 12 are formed at least partially differently in size. Precisely, the central through openings 7, 9 of the circular grinding blanks packet 2 are formed getting larger along a longitudinal portion extending parallel to the axis of rotation D and which extends starting from the front side 4 towards the center, wherein the through opening 7 of the center circular grinding blank 6 is the largest. Furthermore, the central through openings 7, 9 of the grinding blanks packet 2 is formed decreasing in size along a further longitudinal portion extending following and parallel to the axis of rotation D and which extends starting from the center towards the rear side 5. The through opening 9 of both of the final circular blanks 8 is formed identical and is smaller than the through openings 7 of the grinding blanks 6. Starting from the front side 5 of the in this case five grinding blanks 6 of the grinding disc 3, arranged between the final blanks 8, the first and the fifth and the second and the third circular grinding blank 6 are formed identical in shape and size.

(31) The diameters of the through openings 7, 9 of the individual circular grinding blanks 6 and of the final circular blank 8 arranged at the front side 4 are formed stepped in a longitudinal portion, which extends starting from the front side 4 towards the center, such that annular portions 11, 23, laying open facing the rear side 5, are formed, with which these circular grinding blanks 6 and the front-sided final circular blank 8 are arranged in abutment to step-like formed attachment faces 12, 24 of the backing plate 1 and are fixed thereto. The diameters of the through openings 7, 9 of the further individual circular grinding blanks 6 and of the final circular blank 8 arranged at the rear side 5 are formed stepped in a further longitudinal portions, extending starting from the center of the circular grinding blanks packet 2 towards the rear side 5 such that annular portions 11, 23 laying open facing the front side 4, are formed, with which these circular grinding blanks 6 and the rear-sided final circular blank 8 are arranged in abutment to step-like formed attachment faces 12, 24 of the backing plate 1 and are fixed thereto. Thus, it is ensured, that an as large as possible face of the individual circular grinding blanks 6 and of the final circular blanks 8 abut the backing plate 1.

(32) In a further embodiment, the last or the last and further layers, arranged in front of the circular grinding blanks 6, can also be inserted with the grain side against the other layers and bonded by pouring. In this case, the operator can use both sides and/or reverse the grinding disc 3. This can be of advantage, when the layers are formed varyingly, for example contain different grain sizes. However, it can also be of advantage in identical circular grinding blanks 6, as the flexibility of the circular grinding blanks 6 is generally distinctly smaller in grain direction. Thus, the two grinding coatings of neighboring abutting circular grinding blanks 6 stabilize each other and the grinding disc 3 is more rigid.

(33) Finally, in a further special embodiment, the pouring of the backing plate 1 can also be completely omitted. In this case, a backing plate, for example a frustum-like plate from ABS-plastics or other material, which is commonly used for support plates of circular grinding blanks plates (flap grinding discs), can be used. On this, the circular grinding blanks 6 are fixed with a mastic system.

(34) The circular grinding blanks 6 consist of grinding means on a substrate. The used substrate can be a woven fabric, scrim or flies (also pressed). The whole range of common substrates for grinding means on substrates is possible, also combinations, like for example paper-textile or other material combinations known on the market or (weak) vulcanized fibers, which wear during operation, to ensure a continuous wear of the substrate. In a preferred embodiment, the substrate and/or the finished circular grinding blanks 6 and/or the final circular blanks 8 are as far as possible strain isotropic. Thus, the substrate or the circular grinding blanks 6 or the final circular blanks 8 wear as far as possible even, i.e. circular. Tensile strengths in warp- and weft direction or also in the diagonals should be as far as possible identical. Examples are for example grinding means on substrates and substrates, like they are used in segmented broad bands. The abrasive cloth and the grinding means on substrate should generally have relative high tensile strengths. In a special embodiment grinding means on substrate with high tear resistance in as far as possible all directions (longitudinally, transversally and diagonally) are used. In a preferred embodiment, the used cloth of the grinding means on substrate is a X- or Y-substrate. In a preferred embodiment, the abrasive grain is a ceramic grain or a mixture thereof with zirconium aluminum and/or aluminum oxide abrasive.