ES2805076T3 - Support device for abrasive elements - Google Patents

Abstract

Support device (1) that is suitable to support an abrasive element (30) and associable to an orbital or random orbital sander machine (50), which includes: - a support body (2) comprising an external face (21) and a central part (3) provided with a series of first through holes (11); - a connection element (6) fixed to said support body (2) and arranged to support said abrasive element (30), said connection element (6) comprising a central part (7) provided with a series of second through holes (12) facing said series of first through holes (11); - a closure element (10); characterized in that said support body (2) comprises an annular cavity (5) made in a peripheral part (4) of said support body (2) around said central part (3) and provided with a series of third through holes (13), wherein the closing element (10) is connectable to said support body (2) to close said annular cavity (5) and form an inner annular chamber (16), said element (10) being provided ) for closing a series of fourth through holes (14) facing a series of fifth through holes (15) made in a peripheral annular part (8) of said connection element (6), said first through holes (11) emerging and said third through holes (13) of said support body (2) in a connection part (21a) of said external face (21) that is suitable for its connection to an air absorption system and sanding dust of said sanding machine (50).

Description

DESCRIPTION

Support device for abrasive elements

The invention relates to support devices for abrasive elements to be mounted on orbital or random orbital sanding machines. In particular, the invention relates to a support device, called a backing pad, adapted to support a disc of abrasive material and connectable to a machine tool that rotates it. Such a support device is described, for example, in WO 2015119521 A1, on which the preamble of claim 1 is based.

Known support devices or back pads normally comprise a generally disk-shaped support body made of plastic or metallic material and a connecting element, also disk-shaped, fixed to a lower face of the body and made of a material. deformable and elastic, generally an elastomeric material or the like. A disc of abrasive material is removably attached to the connecting element, for example, by means of resettable adhesive or glue or by means of a hooking system of the Velcro® type or the like. A connecting element, usually a shaft, is arranged on the upper face of the support body for connection to a rotary clamp of the sanding machine.

In order to allow the sanding machine to absorb the dust generated during the operations of abrasion, sanding or polishing of the processed parts / parts, the backing pad and the disk are provided with a plurality of through holes. More precisely, the body and the connecting element are provided with a variable number of through holes, six or more, arranged circumferentially around an axis of rotation of the backrest pad and also with different sizes. For proper passage of air and absorbed powders, the through holes in the body and the fastener are aligned and coaxial. For the same reason, the through holes in the abrasive disc must also coincide with those in the backing pad. The through holes of the backing pad exit on the upper face of the body in an absorption sleeve of the sanding machine and into the same, said sleeve surrounding the twist grip and forming an internal chamber connected to an absorption system. The absorption of air also allows the abrasive disc to be cooled, which can reach high temperatures during use.

A drawback of the known backing pads is that, for correct dust absorption, the abrasive disc should be mounted so that its holes are aligned and coincide with those of the backing pad. However, during use, due to mechanical stresses, the abrasive disc can move and rotate, changing the alignment of the holes.

The through holes made in the backing pad do not allow the latter to be cooled efficiently. During intensive use of the back pad, the increase in temperature can compromise the connection between the body and the connecting element, even resulting in their separation. In fact, the connection between the two parts is generally carried out by abrasive glues and adhesives, which can deteriorate at high temperatures. High temperatures can also further damage the abrasive disc material or limit its life and / or performance.

Another drawback is that the through holes can be made only in the central part of the backing pad for attachment to normal absorption sleeves mounted on sanding machines. Therefore, the peripheral areas or crowns of the backing pad and the abrasive disc cannot be provided with holes for absorbing dust and for cooling, unless absorber sleeves with a larger size and consequently more are installed. expensive and inconvenient, on sanding machines. Furthermore, if abrasive discs with different hole configurations (number, sizes, arrangements) are used, for example, to perform specific operations, it is necessary to use specific backing pads provided with a supporting body and a connecting element with hole geometries correspondingly, with a resulting increase in production and storage costs.

In order to overcome some of the aforementioned drawbacks, support devices or backing pads have been made with an inner chamber for the passage of air and absorbed dust. More precisely, the body of the backing pad has an upper part provided with a cavity and a lower part in the shape of a disc that closes the cavity to form the inner chamber. The lower disk can have holes even in one of its peripheral crowns in a similar way to the deformable connecting element attached to it to support the abrasive disk. Instead, the upper part of the body has a plurality of through-holes in its central part for connection to a standard absorption sleeve on sanding machines. In this way, it is possible to absorb air over the entire surface of the abrasive disc without the need to use additional absorber sleeves.

A drawback of said backing pads is that, in use, the peripheral annular part of the inner chamber tends to close due to the accumulation of dust: in fact, the absorbed air tends to pass mainly through the holes of the lower disk. and the part of the inner chamber in front of the outlet holes made in the central part of the upper part of the body, also due to the height or thickness of the inner chamber are necessarily limited. In fact, in order not to excessively increase the thickness of the backing pad, it is necessary that the height of the chamber be reduced. As is known, increasing the thickness of the backing pad implies an increase in its vibrations and oscillations during use, that is, a lower precision and efficiency in operations.

Another drawback of this type of back pad is that the body, being provided with said inner cavity (in particular, its upper part provided with a wide cavity) is structurally less robust and resistant than conventional back pads, and the Fixing to the lower disc with holes in the upper part is less secure and robust.

Document WO 2011/021087 describes a support device or backing pad for abrasive elements in the form of sheets that comprises a first disk-shaped body having a rear surface arranged for attachment to a machine tool and traversed in its thickness by first absorption openings designed for connection to an absorption device in use. The backing pad comprises a second disc-shaped body associated with a front surface of the first body and having a substantially flat front surface where it is possible to arrange a flat abrasive element. The second body is traversed in its thickness by a plurality of second absorption openings in communication with the first absorption openings. The second absorption openings are densely distributed over substantially the entire area of the front surface or at least a part thereof. The face of the front surface, in the parts without the second absorption openings, has a channel open outward from the second disc-shaped body and in communication with the second absorption openings.

WO 2015/119521 discloses a backing pad with grooves for multi-hole sanding discs, comprising an upper part, a middle part and a lower part joined together by a fixing system. The upper part, with a truncated cone shape, comprises absorption holes and a central hole. The intermediate part comprises absorption grooves and a central hole and is provided on its rear face with absorption channels delimited by raised walls. The lower part, with a truncated cone shape, and where the intermediate part is mounted, comprises grooves, a central hole and absorption grooves with an arrangement according to concentric and equidistant rings and with a size that increases from the center to the periphery. WO 2012/019286 describes a backing pad or support device for use with a surface treatment apparatus including a support plate with a fixing plate for a shock absorber and a support cushion with a first face and a second face. . The support device can also include a porous interface layer provided with an outer face. A layer of a first adhesive is arranged on the outer face and extends into the interface layer and a layer of a second adhesive is applied to the layer of the first adhesive. The second adhesive can be selected for removable bonding to an abrasive sheet. The first and second adhesives can be selected such that the adhesive bond between the first adhesive and the second adhesive is stronger than the adhesive bond between the second adhesive and the abrasive sheet.

An object of the invention is to improve the known support devices or backing pads for abrasive elements to be mounted on orbital or random orbital sanding machines.

Another objective is to provide a support device that allows the dust generated during abrasion, sanding or polishing operations to be efficiently and effectively absorbed and, at the same time, optimally cooling the body of the device and, above all, the abrasive element. .

Another objective is to implement a support device that can be easily configured and mounted for connection to different types of abrasive elements and, in particular, with different hole configurations (number, size, arrangements).

A further object is to provide a particularly robust and resistant support device even for intensive use.

A further objective is to implement a support device that can be used efficiently and with high performance on sanding machines fitted with standard absorption sleeves. These and other objectives are obtained by means of a support device for abrasive elements according to one or more of the following claims.

It is possible to improve the understanding and implementation of the invention by referring to the attached drawings, which show an illustrative and non-limiting embodiment, where:

figure 1 is a plan view, from above, of the support device of the invention;

figure 2 is a section according to line II of figure 1 illustrating the support device of the invention associated with an absorption sleeve of a sanding machine, represented by a dashed line;

figure 3 is an enlarged detail of the device of figure 1 associated with an abrasive element; figure 4 is a bottom plan view of the device of figure 1 without a connection element for the abrasive element, to more clearly show an underlying support element and closure element;

figure 5 is a plan view from below of the support body of the device of figure 1; figure 6 is a plan view of the closure element;

figure 7 is a perspective view of the support body of figure 5;

figure 8 is a schematic side view of the support device mounted on a sanding machine and supporting an abrasive element;

figure 9 is a section according to line IX-IX of figure 5.

With reference to Figures 1 to 8, a support device 1 of the invention suitable to support an abrasive element 30 and associable with an orbital or random orbital sander machine 50, of the type used to perform sanding, milling, abrasion processing is illustrated. or polishing on surfaces and objects.

More precisely, the support device 1, also called backrest pad, includes a support body 2 comprising an external face 21 and a central part 3 provided with a series of first through holes 11, and a connection element 6 fixed to the support body 2 and arranged to support the abrasive element 30. The connection element 6 comprises a central part 7 provided with a series of second through holes 12 facing the series of first through holes 11 of the support body 2. The latter also comprises an annular cavity 5 made in a peripheral part 4 of said support body 2, in particular, on an inner face 22 opposite the outer face 21, and around the central part 3. The annular cavity 5 is provided of a series of third through holes 13 emerging on the external face 21.

The back pad 1 further comprises a closure element 10 which is connectable to the support body 2 to close the annular cavity 5 and form an inner annular chamber 16. The closure element 10 is provided with a series of fourth through holes 14 facing a series of fifth through holes 15 made in a peripheral annular portion 8 of the connecting element 6. The first through holes 11 and the third through holes 13 of the support body 2 come out in a connection part 21a of the external face 21 of the latter arranged to be attached to an air and dust absorption system of the sanding machine 50. More precisely, and as shown in figure 2, the connection part 21a is arranged inside an absorption chamber 52 formed with the same support body 2 by means of an absorption cover 51 of the absorption system. air and dust sanding from sanding machine 50.

As illustrated in Figure 3, the abrasive element 30 comprises at least one series of sixth through holes 31 and a series of seventh through holes 32 arranged nearly in correspondence and aligned, respectively, with respect to the second through holes 12 and fourth through holes 14 of the connecting element 6.

The support body 2 and the closure element 10 are made of plastic, in particular high-density plastic.

Instead, the connecting element 6 is made of deformable and flexible material, for example elastomeric material, in particular rubber, to elastically support the abrasive element, adaptable to the shape of the surface to be processed.

The connection element 6, in addition to being fixed to the inner face 22 of the support body 2, is also fixed to the closure element 10. Fixing is carried out by means of known type, such as, for example, glues or adhesives, or by ultrasonic welding.

The first through holes 11 of the support body 2 and the second through holes 12 of the connecting element 6 are nearly aligned and coaxial to ensure excellent passage of air and dust absorbed by the absorption system of the sanding machine 50 in use, as explained in more detail below in the description.

The first through holes 11 and the second through holes 12 therefore form a first central absorption path for air and sanding dust in a central part of the backing pad 1 and of the abrasive element 30.

As particularly illustrated in Figure 9, in order to allow more efficient absorption and consequently faster removal of sanding dust within the absorption cover 51 of the sander, the first through holes 11 they are conical and, in particular, divergent, that is to say with an increasing cross section, towards the external face 21. Said conicity of the first holes 11 in fact allows an increase in the speed of the absorption of the air.

It is also provided in a variant of the support device 1, not illustrated in the figures, that the first through holes 11 are almost cylindrical.

The fourth through holes 14 of the closure element 10 and the fifth through holes 15 of the connecting element 6 are preferably nearly aligned or substantially coaxial. The third, fourth and fifth through holes 13, 14, 15, in addition to the inner peripheral chamber 16, form a peripheral air and dust absorption path in a peripheral part of the backing pad 1 and the abrasive element 30.

In the illustrated embodiment, each series of through holes 11, 12, 13, 14, 15 comprises a plurality of respective through holes with the same respective shape and size, in particular, with the same circular shape and the same diameter. However, it is possible for each series of through holes to comprise through holes with different sizes and / or shapes (circular, elliptical, ...).

Each series of through holes further comprises a respective number of holes (the same or different) arranged according to an arrangement or distribution adapted to ensure an optimal flow of air and absorbed sanding dust without compromising in any case the strength and mechanical hardness of the various components. , that is to say, of the support body 2, of the connection element 6 and of the closure element 10. In the illustrated embodiment, the third through holes 13 are arranged along a circumference around the central portion 3 and are larger in size than the first holes 11 to increase ^{absorption and passage of air and dust through the inner chamber} 16 ^{, as explained in more} detail below in the description.

The closure element 10 can be selected from a group of closure elements with different configurations of the fourth through holes 14 and can be connected to the support body 2 according to the characteristics and configurations of the through holes of the abrasive element 30 to be used. The latter, of a known type and not described in detail, generally comprises a disk of abrasive material provided with a plurality of through holes with equal or different sizes and arranged to ensure the best absorption of the powders generated during processing.

In the illustrated embodiment, the support body 2 has a disk shape that is almost circular, in particular, with axial symmetry with respect to the central axis X around which the entire back pad 1 rotates when connected to the sanding machine 50 and moves through it. The support body 2 also has a thickness that decreases starting from the central part 3 and towards the peripheral part 4. With reference to the section of figure 2, the annular cavity 5 has an elongated rectangular section and has an inner edge 25 and an outer edge 24, both with a circular shape, adapted to receive and support the closure element 10. The latter has a flat and annular shape, in particular a circular crown shape.

To support and allow a more stable connection of the closure element 10 to the support body 2, the annular cavity 5 comprises a plurality of support shafts 27 arranged around the central part 3. More precisely, each support shaft 27 has a tapered end 27a arranged to be attached to a respective fourth through hole 14 of the closure element 10. The portion of the tapered end 27a emerging from the hole of the closure element 10 can be reshaped or plastically deformed to tightly lock the closure element 10 with respect to the support body 2 in a mounting step of the backing pad 1.

With particular reference to Figure 7, the support body 2 comprises on its inner face 22 opposite the outer face 21 and in the central part 3 an additional cavity 9 which is in fluid connection with the outer face 21 by means of a plurality of respective grooves 17 and through openings 18, 19, the latter emerging in particular in the connection part 21a of the external face 21. The additional cavity 9 faces and is connected to a central hole 26 of the connection element 6. Thanks to said central hole 26 and the additional cavity 9 connected to the connection part 21a by means of a plurality of through openings 18, 19 it is possible to efficiently absorb most of the dust that accumulates in the abrasive element 30 and in the pad 1 backing pad in the area adjacent to and around the central axis X, where peripheral velocities (tangentially ejecting dust from the backing pad) are almost zero.

In the illustrated embodiment, the additional cavity 9 is connected to the external face 21 by means of four holes 17 and four first through openings 18, arranged angularly spaced from each other around the central axis X. Four second through openings 19, each made adjacent to one slot 17 respective, directly connect a lower wall 9a of the additional cavity 9 to the external face 21.

The first and second through openings 18, 19 and the additional cavity 9 of the support body 2 and the central hole 26 of the connecting element 6 form a second central air and dust absorption path in the central part of the backing pad 1 and of the abrasive element 30, in particular around the central axis X.

The additional cavity 9 further comprises a central opening 29 for connecting the backing pad to the sanding machine 50, in particular by means of connection means 20. The central aperture 29 is, for example, a respective circular hole made in the lower hole 9a of the additional cavity almost coaxial with respect to the central axis X and protruding on the outer face 21.

In the illustrated embodiment, the backing pad 1 comprises connection means 20 that make it possible to reversibly connect the corresponding backing pad to the sanding machine 50. The connection means comprise in particular a shaft 20 fixed to the central part 3 of the body 2, extending from the outer face 21 and arranged for attachment to clamping means of the sanding machine 50. More precisely, the shaft 20 is inserted into the central opening 29 and has a shaped head 20a which is mounted and fixed in additional cavity 9.

Fixing means of known type are used to join the abrasive element 30 to the connecting element 6, said fixing means comprising, for example, adhesives or reversible hooking systems of the Velcro® type.

In use, the backing pad 1 of the invention supporting an abrasive element 30 attached to the connecting element 6 rotates about the central axis X of the sanding machine 50 where it is mounted. The depression created in the absorption chamber 52, formed by the absorption cover 51 with the upper face 21 of the support body 2, determines the absorption of air and, above all, of the dust produced during use. Thanks to the structure of the backing pad 1 of the invention, air and sanding dust are efficiently absorbed and removed by the abrasive element 30 in its central part and in its peripheral part. More precisely, the first through holes 11 of the support body 2 and the second through holes 12 of the connecting element 6 form a first central path for the passage of air and powder, in the central part 3 of the support body 2. The extraction of sanding dust in the central part of the backing pad 1 is facilitated by the taper of the first through holes 11, which allows an increase in the absorption speed.

Dust extraction is also facilitated by the through openings 18, 19 and by the additional cavity 9 of the support body 2 and by the central hole 26 of the connecting element 6 that form the second central absorption path always in the central part of the backing pad 1 and of the abrasive element 30, in particular, around the central axis X, that is, in the area where most of the dust accumulation is present.

The absorption of dust and its removal from the peripheral part of the backing pad 1 and the abrasive element 30 is carried out effectively by the third through holes 13, by the inner peripheral chamber 16 of the support body 2, through the fourth through holes 14 of the closing elements 10 and through the fifth through holes 15 of the connecting element 6.

In this way, thanks to the presence of three different and separate absorption paths (two central and one peripheral) it is possible to optimally extract the dust during processing. Furthermore, unlike known support devices or back pads, the inner peripheral chamber, being provided with respective and separate through holes (series of third through holes 13) that communicate it with the absorption chamber 52 formed by the sleeve 51 absorption of the sanding machine 50, is subject to a constant absorption flow and is not subject to blockages or obstructions caused by the accumulation of dust.

The closure element 10 also advantageously contributes to obtaining said result, since it is possible to select it with a suitable configuration of the fourth through holes 14, in order to make the backing pad 1 suitable for a specific type of abrasive element 30 and / or operating conditions. In particular, it is possible to select the closure element 10 during the assembly of the backing pad 1 according to the physicochemical characteristics of the abrasive element and / or the configuration of its through holes (number, size, arrangement).

Optimal air absorption through the backing pad 1 of the invention also allows the latter to be effectively cooled and, in particular, the abrasive element 30, in order to avoid damage to the material from which it is made and to increase its durability. and / or performance.

It should also be noted that the backrest pad 1 of the invention, having an inner peripheral chamber 16 and a plurality of through holes, is especially resistant and robust, since it comprises a support body 2 made in a single piece and with a peripheral 4 and, above all, a central part 3 arranged around the central axis X to which the connecting element 6 is directly attached. The closure element 4 connected and fixed to the inner face 22 of the support body 2 to form the inner peripheral chamber 16 contributes to reinforcing the structure of the backing pad 1.

Finally, it should be noted that, because the holes and through-holes made in the support body 2 all come out in a connection part 21a of the external face 21 of said support body 2 and have limited sizes, the pad 1 of The backing of the invention can be used efficiently and with high performance in sanding machines fitted with standard and non-enlarged absorption sleeves.

Claims (13)

1. Support device (1) that is suitable to support an abrasive element (30) and associable to an orbital or random orbital sander (50), which includes: - a support body (2) comprising an external face (21) and a central part (3) provided with a series of first through holes (11); - a connection element (6) fixed to said support body (2) and arranged to support said abrasive element (30), said connection element (6) comprising a central part (7) provided with a series of second through holes (12) facing said series of first through holes (11); - a closure element (10); characterized in that said support body (2) comprises an annular cavity (5) made in a peripheral part (4) of said support body (2) around said central part (3) and provided with a series of third through holes (13), wherein the closure element (10) is connectable to said support body (2) to close said annular cavity (5) and form an internal annular chamber (16), said element (10) being provided ) for closing a series of fourth through holes (14) facing a series of fifth through holes (15) made in a peripheral annular part (8) of said connection element (6), said first through holes (11) emerging and said third through holes (13) of said support body (2) in a connection part (21a) of said external face (21) that is suitable for its connection to an air absorption system and sanding dust of said sanding machine (50). Support device (1) according to claim 1, wherein said first through holes (11) of said support body (2) and said second through holes (12) of said connecting element (6) are almost aligned. Support device (1) according to claim 1 or 2, wherein said first through holes (11) are conical, in particular, divergent towards said external face (21). Support device (1) according to any of the preceding claims, wherein said fourth through holes (14) of said closing element (10) and said fifth through holes (15) of said connecting element (6) are almost aligned. Support device (1) according to any of the preceding claims, wherein said closure element (10) is selectable from a group of closure elements with different configurations of fourth through holes (14) and is connectable to said body ( 2) of support according to characteristics and configuration of through holes of said abrasive element (30) to be used. Support device (1) according to any of the preceding claims, wherein said annular cavity (5) has an inner edge (25) and an outer edge (24) arranged to receive and support said closure element (10). Support device (1) according to any of the preceding claims, wherein said annular cavity (5) comprises a plurality of support shafts (27) arranged around said central part (3) to support said element (10) of closure, in particular, each support shaft (27) having a tapered end (27a) arranged to be attached to a respective fourth through hole (14) of said closure element (10). Support device (1) according to any of the preceding claims, wherein said support body (2) comprises an inner face (22) opposite said outer face (21) and an additional cavity (9) made in said face interior (22) in said central part (3), said additional cavity (9) being connected to said external face (21) by means of a plurality of respective slots (17) and through openings (18, 19) that exit in said part ( 21a) of connection of said external face (21), said additional cavity (9) facing a central hole (26) of said connection element (6) and being connected to it. Support device (1) according to claim 8, wherein said additional cavity (9) comprises a central opening (29) for connection to said sanding machine (50), in particular by means of connection means (20). Support device (1) according to any of the preceding claims, comprising connection means (20) for reversibly connecting said support device (1) to said sanding machine (50), said connection means comprising a shaft (20) that is fixed to said central part (3) of said support body (2), extends from said external face (21) of said support body (2) and is arranged to be attached to means of fastening of said sanding machine (50). Support device (1) according to any of the preceding claims, wherein said body (2) support and said closure element (10) are made of plastic. Support device (1) according to any of the preceding claims, wherein said connecting element (6) is also fixed to said closing element (10). Support device (1) according to any of the preceding claims, comprising fixing means for joining said abrasive element (30) to said connecting element (6), said abrasive element (30) comprising at least one series of sixths through holes (31) and a series of seventh through holes (32) which almost correspond, respectively, with said second through holes (12) and with said fifth through holes (15) of said connecting element (6).