BACKING PLATE UNIT

Abstract

 Backing plate unit (10) for a grinding machine, in particular for a random orbital or dual action or rotary orbital grinding machine, comprising a backing plate (14) having a front side (16) configured to fix an abrasive disc (12) and a back side configured to be removably attached to the grinding machine and to be driven, wherein the backing plate (14) comprises at least one suction opening (20) that is configured to connect the front side (16) with any type of suction device and preferably penetrates the backing plate (14), wherein the backing plate (14) comprises a hook-and-loop layer (22) arranged on the front side (16) and configured to fix an abrasive disc (12) by means of a hook-and-loop connection, and wherein at least one channel (24) is formed in the hook-and-loop layer (22) by partially eliminating or removing hooks and/or loops of the hook-and-loop layer (22), wherein the channel (24) is fluidly connected to the at least one suction opening (20) of the backing plate (14) .

Description

[0001] The invention relates to a backing plate unit for a grinding machine, in particular for a random orbital or dual action or rotary orbital grinding machine, comprising a backing plate having a front side configured to fix an abrasive disc, in particular a sanding paper grinding disc, and a back side configured to be removably attached to the grinding machine and to be driven, wherein the backing plate comprises at least one suction opening that is configured to connect the front side with any type of suction device and preferably penetrates the backing plate, wherein the backing plate comprises a hook-and-loop layer arranged on the front side and configured to fix an abrasive disc by means of a hook-and-loop connection.

[0002] Such backing plate units are well known in the prior art. Those backing plate units often have a plurality of suction openings arranged in a specific suction opening pattern, wherein the grinding discs, in particular the sanding paper grinding discs are also having suction openings that are arranged in the same pattern as the suction opening pattern of the backing plate unit. Via the suction openings of the backing plate unit and of the grinding disc, abrasive dust can be removed by suction cleaning.

[0003] However, those systems comprising such a backing plate unit and grinding disc make it difficult for a machine operator to fix the sanding paper grinding disc to the front side of the backing plate unit, because not only the outer edge of the sanding paper grinding disc and the backing plate unit have to be superimposed but also the suction opening pattern of the backing plate unit and of the sanding paper grinding disc have to be superimposed. Accordingly, the suction openings of the backing plate unit and of the grinding disc are often times not superimposed completely accurate, thereby reducing or making impossible the dust removal effect.

[0004] Therefore, some companies have started to provide grinding discs wherein the abrasive grain is attached to a mesh structure which is then fixed via hook-and-loop connection to the backing plate unit. The holes in the mesh structure can be used to remove abrasive dust via suction cleaning, wherein the attachment of the grinding discs is facilitated because a machine operator does not have to superimpose the suction openings when attaching the grinding disc to the backing plate unit. Nevertheless, the suction effect of these abrasive meshes is less efficient and the hook-and-loop connection hooks of the backing plate units can be destroyed.

[0005] Another approach is known from the prior art such as from US 2012/0315833 A1 wherein suction openings are arranged in the area of an outer region of the backing plate. By means of the rotational speed of the backing plate during grinding, the dust is centrifuged outwards by the centrifugal force in the hook-and-loop layer and the dust is then sucked off at the outer region of the backing plate through the suction openings that are arranged there at the border of the backing plate. Nevertheless, the hook-and-loop layer tends to become clogged from the abrasive dust.

[0006] It is therefore an object of the present invention to provide a backing plate unit for a grinding machine which allows for an easy and exact fixation of a grinding disc to the front side of the backing plate, wherein an efficient dust removal capacity shall be provided independent from the design of the abrasive discs and their alignment with the at least one suction opening of the backing plate.

[0007] This object is solved by a backing plate unit according to the features of claim 1. Such a backing plate unit is characterized in that at least one channel is formed in the hook-and-loop layer by partially eliminating or removing hooks and/or loops of the hook-and-loop layer, wherein the channel is fluidly connected to the at least one suction opening of the backing plate. It is particularly preferred if the backing plate is circular, wherein the front side of the backing plate is configured to fix circular sanding paper abrasive discs. By providing at least one channel in the hook-and-loop layer that is fluidly connected to the at least one suction opening, abrasive dust can be sucked or blown through the suction opening wherein clogging of the hook-and-loop connection can be avoided. Moreover, a fixation of an abrasive disc can be facilitated because suction openings of the abrasive disc can be more easily superimposed with the channel formed in the hook-and-loop layer.

[0008] It is therefore particularly preferable if the channel is configured to form a suction channel with the hook-and-loop layer of an abrasive disc fixed to the front side of the backing plate. Accordingly, the channel in the hook-and-loop layer is preferably formed as a notch channel which can be closed on the open side by an abrasive disc fixed to the front side of the backing plate to thereby form the suction channel.

[0009] In order to avoid clogging and in order to provide a sufficient flow cross-section for the removal of abrasive dust, it is particularly preferred if the channel has a channel width, in particular perpendicular to the rotation axis, of about 1 mm to about 30 mm, preferably of about 1 mm to about 20 mm, more preferably of about 1 mm to about 20 mm, more preferably of about 1 mm to 10 mm. It is also possible that a plurality of channels is provided wherein different channels may have a different channel width.

[0010] In another preferred embodiment of the backing plate unit, at least one suction opening is arranged concentrically to a middle axis of the backing plate unit. It is also possible that the suction opening is arranged with a certain offset to the middle axis. Moreover, it is possible that a plurality of suction openings is provided in the backing plate that penetrate the backing plate.

[0011] In case at least one suction opening is provided that is arranged concentrically to the middle axis of the backing plate unit, it is particularly preferred if at least one channel is provided that extends radially. The radial arrangement or radial direction of the channel is understood to mean that the channel extends from a center to an outside of the backing plate.

[0012] In another preferred embodiment at least one channel is provided in the hook-and-loop layer that is formed circular and arranged concentrically to a middle axis of the backing plate unit. It is particularly preferred if a plurality of channels is provided that are arranged concentrically to the rotation axis, wherein these channels can be fluidly connected to the suction opening provided in the backing plate via at least one channel that extends radially.

[0013] In an embodiment of the backing plate unit that is particularly cheap to manufacture, at least one channel is provided in the hook-and-loop layer that is arranged parallel to a tangent laid to the backing plate. Preferably, a plurality of channels is provided that are parallel to each other.

[0014] It is particularly preferred if at least one channel is provided in the hook-and-loop layer that is arranged perpendicular to the channel arranged parallel to the tangent laid to the backing plate. Even more preferably, also a plurality of channels is provided that are perpendicular to the channels arranged parallel to the tangent laid to the backing plate.

[0015] According to a preferred embodiment of the backing plate unit, the plurality of channels in the hook-and-loop layer is formed in a grid.

[0016] According to another preferred embodiment of the backing plate unit, the hook-and-loop layer comprises hook-and-loop connection hooks wherein abrasive discs have to be chosen that comprise hook-and-loop connection loops configured for mutual connection with the hook-and-loop connection hooks. Nevertheless, it is also possible that hook-and-loop connection loops are arranged in the hook-and-loop layer of the backing plate unit wherein abrasive discs have to be chosen that comprise hook-and-loop connection hooks configured for mutual connection with the hook-and-loop connection loops.

[0017] In order to provide a sufficient strength of the hook-and-loop connection between the front side of the backing plate and a grinding disc, it is particularly preferred if the hook-and-loop connection hooks form at least 20 % to 30 % of the surface of the hook-and-loop layer.

[0018] Preferably, the hook-and-loop connection hooks extend from the backing plate in a height of about 0,3 mm to about 0,6 mm, preferably in a height of about 0,4 mm.

[0019] In order to provide a sufficient flow cross section when a grinding disc is attached to the front side of the backing plate, it is particularly preferred if there are essentially no hook-and-loop connection hooks in the area of the channels.

[0020] According to a preferred embodiment of the backing plate unit, the hook-and-loop connection hooks of the hook-and-loop layer are attached to the front side of the backing plate by an intermediate layer comprising polyurethane.

[0021] The above-mentioned object is also solved by a method of manufacturing a backing plate unit according to the features of claim 16, in particular a backing plate unit for a grinding machine, in particular for a random orbital or dual action or rotary orbital grinding machine, comprising a backing plate having a front side configured to fix an abrasive disc and a back side configured to be removably attached to the grinding machine and to be driven, wherein the backing plate comprises at least one suction opening that is configured to connect the front side with any type of suction device and preferably penetrates the backing plate, wherein the backing plate comprises a hook-and-loop layer arranged on the front side and configured to fix an abrasive disc by means of a hook-and-loop connection.

[0022] Such a method is characterized by forming at least one channel in the hook-and-loop layer, that is fluidly connected to the suction opening of the backing plate by partially eliminating or removing hook-and-loop connection hooks of the hook-and-loop layer, preferably by means of milling, waterjet cutting or lasing.

[0023] Further details and advantages of the invention can be taken from the following description, on the basis of which the embodiments of the invention that are represented in the figures are described and explained in more detail.

[0024] Respective figures are showing:

Figure 1

a sectional view of a backing pad unit according to the invention and of an abrasive disc;

Figure 2

a bottom view of a backing pad unit according to a first embodiment of the invention;

Figure 3

a bottom view of a backing pad unit according to a second embodiment of the invention; and

Figure 4

various front views of sections of abrasive discs configured to be fixed to a backing plate unit according to the invention.

[0025] In Figure 1 a sectional view of a backing pad unit 10 according to the invention and of an abrasive disc 12 are shown, wherein Figure 2 depicts a bottom view of a backing pad unit 10 according to a first embodiment and wherein Figure 3 depicts a bottom view of a backing pad unit 10 according to a second embodiment.

[0026] The backing plate unit 10 is configured to be attached to a rotary grinding machine and comprises a circular backing plate 14 having a front side 16 configured to fix the abrasive disc 12, in particular a sanding paper grinding disc, and a back side configured to be removably attached to a grinding machine and to be driven around a middle axis 18, wherein the backing plate 14 comprises at least one suction opening 20 that penetrates the backing plate 14, wherein the backing plate 14 comprises a hook-and-loop layer 22 arranged on the front side and configured to fix the grinding disc 12 by means of a hook-and-loop connection. The hook-and-loop layer 22 comprises hook-and-loop connection hooks 23 wherein abrasive discs 12 have to be chosen that comprise hook-and-loop connection loops 25 configured for mutual connection with the hook-and-loop connection hooks 23. The hook-and-loop connection hooks 23 extend from the backing plate 14 in a height of about 0,3 mm to about 0,6 mm, preferably in a height of about 0,4 mm. The hook-and-loop connection hooks 23 of the hook-and-loop layer 22 are attached to the front side 16 of the backing plate 14 by an intermediate layer (not shown) comprising polyurethane.

[0027] A plurality of channels 24 are formed in the hook-and-loop layer and are fluidly connected to the at least one suction opening 20 of the backing plate 14. The at least one suction opening 20 is arranged concentrically to the rotation axis 18. It is also possible that the suction opening 20 is arranged with a certain offset to the rotation axis 18. Moreover, it is possible that a plurality of suction openings 20 are provided in the backing plate 14 that penetrate the backing plate 14.

[0028] The channels 24 are configured to form suction channels with a hook-and-loop layer 26 of the abrasive disc 12 fixed to the front side of the backing plate. There are essentially no hook-and-loop connection hooks 23 in the area of the channels 24. Accordingly, the channels 24 in the hook-and-loop layer 22 are formed as a notch channels which can be closed on the open side by the grinding disc 12 fixed to the front side 16 of the backing plate 14 to thereby form the suction channels.

[0029] By providing the channels 24 in the hook-and-loop layer 22 that are fluidly connected to the at least one section opening 20, abrasive dust can be sucked or blown through the channels 24 and through the suction opening 20 wherein clogging of the hook-and-loop connection can be avoided. Moreover, a fixation of an abrasive disc 12 can be facilitated because suction openings of the grinding disc 12 (not shown) can be more easily superimposed with the channels 24 formed in the hook-and-loop layer 22.

[0030] In order to avoid clogging and in order to provide a sufficient flow cross-section for the removal of abrasive dust, the channels have a channel width 26 perpendicular to the rotation axis 18, of about 1 mm to about 30 mm, preferably of about 1 mm to about 20 mm, more preferably of about 1 mm to about 20 mm, more preferably of about 1 mm to 10 mm. It is also possible that a plurality of channels 24 is provided wherein different channels 24 may have a different channel width 26.

[0031] In the embodiment of Figure 2, at least one suction opening 20 is provided that is arranged concentrically to the rotation axis 18, wherein a part of the channels 24 extends radially. The radial arrangement or radial direction of the channels 24 is understood to mean that the channels 24 extend from a center (i.e. from the middle axis 18) to an outside 28 of the backing plate 14.

[0032] In the embodiment of Figure 2 some channels 24 are provided in the hook-and-loop layer 22 that are formed circular and arranged concentrically to the middle axis 18. These channels are fluidly connected to the suction opening 20 provided in the backing plate 14 via the channels 24 that extend radially.

[0033] In the embodiment of Figure 3, which is particularly cheap to manufacture, the channels 24 in the hook-and-loop layer 22 are formed in a grid, wherein the channels 24 are arranged parallel to a tangent laid to the backing plate 14, wherein channels 24 are provided that are arranged perpendicular to the channels 24 arranged parallel to the tangent laid to the backing plate 14.

[0034] In order to provide a sufficient strength of the hook-and-loop connection between the front side 16 of the backing plate 14 and a grinding disc 12, it is particularly preferred if the hook-and-loop connection hooks 23 form at least 20 % to 30 % of the surface of the hook-and-loop layer 22.

[0035] Figure 4 shows various front views of sections 30, 32, 34, 36, 38, 40 of abrasive discs 12 configured to be fixed to a backing plate unit 10.

[0036] The abrasive discs 12 according to sections 30, 32, 34, 36, 38, 40 have different hole patterns comprising suction openings 42 with different arrangement and different opening diameter.

[0037] With the backing plate unit 10 it is possible to fix abrasive discs 12 with different hole patterns such as the hole patterns shown in sections 30, 32, 34, 36, 38 and 40 to the backing plate unit 10 such that the suction openings 42 can be superimposed with the channels 24 in the hook-and-loop layer 22 of the backing plate unit 10 in order to efficiently remove abrasive dust without clogging of the hook-and-loop connection between the backing plate unit 10 and the abrasive disc.

Claims

1. Backing plate unit (10) for a grinding machine, in particular for a random orbital or dual action or rotary orbital grinding machine, comprising a backing plate (14) having a front side (16) configured to fix an abrasive disc (12) and a back side configured to be removably attached to the grinding machine and to be driven, wherein the backing plate (14) comprises at least one suction opening (20) that is configured to connect the front side (16) with any type of suction device and preferably penetrates the backing plate (14), wherein the backing plate (14) comprises a hook-and-loop layer (22) arranged on the front side (16) and configured to fix an abrasive disc (12) by means of a hook-and-loop connection, characterized in that at least one channel (24) is formed in the hook-and-loop layer (22) by partially eliminating or removing hooks and/or loops of the hook-and-loop layer (22), wherein the channel (24) is fluidly connected to the at least one suction opening (20) of the backing plate (14).

2. Backing plate unit (10) according to claim 1, wherein the channel (24) is configured to form a suction channel with the hook-and-loop layer (25) of an abrasive disc (12) fixed to the front side (16) of the backing plate (14).

3. Backing plate (10) unit according to claim 1 or 2, wherein the channel (24) has a channel width (26) of about 1 mm to about 30 mm, preferably of about 1 mm to about 20 mm, more preferably of about 1 mm to about 20 mm, more preferably of about 1 mm to 10 mm.

4. Backing plate unit (10) according to any one of the foregoing claims, wherein at least one suction opening (20) is arranged concentrically to a middle axis (18) of the backing plate unit (10).

5. Backing plate unit (10) according to any one of the foregoing claims, wherein at least one channel (24) is provided that extends radially.

6. Backing plate unit (10) according to any one of the foregoing claims, wherein at least one channel (24) is provided in the hook-and-loop layer (22) that is formed circular and arranged concentrically to a middle axis (18) of the backing plate unit (10).

7. Backing plate unit (10) according to any one of the foregoing claims, wherein at least one channel (24) is provided in the hook-and-loop layer (22) that is arranged parallel to a tangent laid to the backing plate (14).

8. Backing plate unit (10) according to claim 7, wherein at least one channel (24) is provided in the hook-and-loop layer (22) that is arranged perpendicular to the channel (24) arranged parallel to the tangent laid to the backing plate (14).

9. Backing plate unit (10) according to any one of the foregoing claims, wherein a plurality of channels (24) is formed in the hook-and-loop layer (22).

10. Backing plate unit (10) according to claim 9, wherein the plurality of channels (24) in the hook-and-loop layer (22) is formed in a grid.

11. Backing plate unit (10) according to any one of the foregoing claims, wherein the hook-and-loop layer (22) comprises hook-and-loop connection hooks (23).

12. Backing plate unit (10) according to claim 11, wherein the hook-and-loop connection hooks (23) form at least 20 % to 30 % of the surface of the hook-and-loop layer (22).

13. Backing plate unit (10) according to claim 11 or 12, wherein the hook-and-loop connection hooks (23) extend from the backing plate (14) in a height of about 0,3 mm to about 0,6 mm, preferably in a height of about 0,4 mm.

14. Backing plate unit (10) according to any one of claims 11 to 13, wherein there are essentially no hook-and-loop connection hooks (23) in the area of the channels (24).

15. Backing plate unit (10) according to any one claims 11 to 14, wherein the hook-and-loop connection hooks (23) of the hook-and-loop layer (22) are attached to the front side (16) of the backing plate (14) by an intermediate layer comprising polyurethane.

16. Method of manufacturing a backing plate unit (10) for a grinding machine, in particular for a random orbital or dual action or rotary orbital grinding machine, comprising a backing plate (14) having a front side (16) configured to fix an abrasive disc (12) and a back side configured to be removably attached to the grinding machine and to be driven around, wherein the backing plate (14) comprises at least one suction opening (20) that is configured to connect the front side (16) with any type of suction device and preferably penetrates the backing plate (14), wherein the backing plate (14) comprises a hook-and-loop layer (22) arranged on the front side (16) and configured to fix an abrasive disc (12) by means of a hook-and-loop connection, characterized by forming at least one channel (24) in the hook-and-loop layer (22), that is fluidly connected to the suction opening (20) of the backing plate (14) by partially eliminating or removing hook-and-loop connection hooks (23) of the hook-and-loop layer (22), preferably by means of milling, waterjet cutting or lasing.

Drawing