This application claims priority under 35 U.S.C. §119 to patent application no. DE 10 2012 214 382.3, filed on Aug. 13, 2012 in Germany, the disclosure of which is incorporated herein by reference in its entirety.
The disclosure relates to an exchangeable abrasive means, in particular an abrasive disc, for use with a known abrasion appliance having a suction extraction arrangement.
The known abrasion appliance in this case has an abrasive-means carrier having suction holes; in particular, there are known abrasive-means carriers that have either five or eight circular suction holes. In the following, all abrasive-means carriers having five circular suction holes are referred to as a five-hole version, and those having eight circular suction holes are referred to as an eight-hole version. In this case, the suction holes of the known abrasive-means carriers each have substantially the same diameter, and, in the case of the five-hole version, are disposed on a first, larger hole-circle diameter, and, in the case of the eight-hole version, are disposed on a second, smaller hole circle diameter, on the respective abrasive-means carrier. On commercially preferred types of abrasion appliances for abrasive discs that have an overall diameter of 125 mm, the suction holes of the five-hole version are distributed uniformly on a hole-circle diameter of approximately 72 mm, while the suction holes of the eight-hole version are distributed uniformly on a hole-circle diameter of approximately 65 mm. Both preferred versions in this case have a suction hole diameter of approximately 10 mm.
Known from U.S. Pat. No. 5,989,112 are abrasive discs having a plurality of through openings that are suitable for use both on abrasion appliances having a five-hole version and on abrasion appliances having an eight-hole version of the suction holes in the abrasive-means carrier, such that, in both cases of use or application, through openings are assigned to the suction holes in the abrasive-means carrier, such that a maximum suction cross section relative to the suction holes is achieved. A through opening in an abrasive disc, or abrasive means, in this case means, in particular, a two-dimensionally extended relief, in particular aperture, of the abrasive disc, or abrasive means, in a direction perpendicular to a working surface provided with means of abrasion. Further, in this context, a maximum suction cross section is understood to mean the sum of the cross-sectional areas of the suction holes in the abrasive-means carrier, such that the one abrasive disc according to U.S. Pat. No. 5,989,112, when disposed in both cases of use, does not limit the maximum suction cross section, owing to the through openings provided in its surface.
This is achieved, according to U.S. Pat. No. 5,989,112, in that the abrasive disc has eight through openings that, in the case of being disposed on an eight-hole version abrasive-means carrier, are suitable for being in alignment with suction holes respectively assigned to them, preferably for being made to overlap the latter, or for their cross-sectional areas to be overlapped by suction holes respectively assigned to them when the abrasive disc is correctly disposed on the abrasive-means carrier. Further, according to U.S. Pat. No. 5,969,112, five of the eight through openings are enlarged in such a manner that, if the abrasive disc is disposed on a five-hole version abrasive-means carrier, they are suitable for being in alignment with suction holes respectively assigned to them, preferably for being made to overlap the latter, or for their cross-sectional areas to be overlapped by suction holes respectively assigned to them when the abrasive disc is correctly disposed on the abrasive-means carrier. In this case, correct disposition of the abrasive disc on an abrasive-means carrier is understood to mean, in particular, a disposition, fastening, separable fastening or mounting that is aligned in such a manner that the through openings are made to overlap the suction holes assigned to them, according to the type of abrasive-means carrier, such that a maximum possible suction cross section is achieved.
However, these known abrasive discs have the disadvantage, on the one hand, that, in both cases of application, the optimum possible working surface is not available and, on the other hand, the connection capacity, in particular attachment capacities, or the connecting or attachment surface of the abrasive disc on the abrasive-means carrier, in particular in the case of known hook/loop or adhesive systems for attaching abrasive discs to an abrasive-means carrier, are adversely affected.
The exchangeable abrasive means according to the disclosure have the advantage that, on the one hand, a sufficiently large maximum suction cross section with, at the same time, significantly improved connection capacity. This results in an advantageously improved service life of the abrasive means according to the disclosure. For this purpose, the abrasive means according to the disclosure has a plurality of through openings, which each have a cross-sectional area that has a centroid, wherein the plurality of through openings can be differentiated into three groups of through openings, the groups differing from each other in the radial disposition of the centroids of the respective through openings. A centroid in this case is understood to mean, in particular, a point in the cross-sectional area that, in the case of a notional homogeneous and isotropic distribution of an assumed area density, would correspond to the center of gravity. In the case of a circular cross section, the centroid corresponds, in particular, to the mid-point of the circle. A first group of the through openings comprises at least one, but not more than four, but preferably two or three through openings of a first cross section that, particularly preferably, is at the same time the largest of the cross sections of all through openings. At least two of the through openings of the first group in this case are disposed on a first circumcircle diameter that is substantially identical to one of the hole-circle diameters, in such a manner that, when the abrasive means is correctly disposed on an abrasive-means carrier, they are in direct alignment with, and can preferably be made to overlap, two suction holes respectively assigned to them.
Further, the abrasive means according to the disclosure has a second group of through openings, of a second, preferably smaller cross section, which comprises at least four through openings that are disposed on a second circumcircle diameter that differs from the first circumcircle diameter.
Advantageous developments and improvements of the features specified in the disclosure ensue from the measures stated in the dependent claims.
In a preferred embodiment, the second group of through openings of an abrasive means according to the disclosure comprises at least five, preferably exactly five or six, through openings.
In an advantageous development of the abrasive means according to the disclosure, at least one third group of through openings is provided, the centroids of these through openings being disposed neither on the first nor on the second circumcircle diameter. Preferably, the third group comprises a plurality of through openings, the centroid of a first part of the plurality lying radially outside of the first circumcircle diameter, and a second part of the plurality lying radially inside the second circumcircle diameter, the through openings of the plurality preferably being disposed such that, when the abrasive means is correctly disposed on an abrasive-means carrier, their cross-sectional areas are each overlapped by the suction holes assigned to them. A particularly effective embodiment is obtained if the third group comprises at least one through opening, whose centroid is disposed between the first and the second circumcircle diameter, the cross-sectional area of this through opening being overlapped by a suction hole assigned thereto, when the abrasive means is correctly disposed on an abrasive-means carrier. Preferably, a cross section of the respective suction hole is touched, at least tangentially, by the cross-sectional area of the through openings, such that the cross-sectional area of the respective through opening lies inside the cross section of the respective suction hole.
An embodiment of an abrasive means according to the disclosure that is particularly easily produced, and also easily applied, is achieved in that the cross-sectional areas of at least one of the groups of through openings are circular. An abrasive means according to the disclosure can be produced particularly inexpensively if the cross-sectional areas of all groups of through openings are circular in form, since circular through openings can be realized by punching technology, for example by means of easily produced tools.
In an advantageous embodiment, the cross-sectional areas of the through openings of the first group are circular and have a uniform first diameter D1_1. Preferably, the first diameter D1_1 of the through openings of the first group is between 70% and 105%, ideally approximately 80% and 100%, of the diameters of the suction holes of the abrasive-means carrier, preferably between 8 mm and 10 mm.
In an advantageous development, the cross-sectional areas of the through openings of the second group are circular and have at least one, preferably two, differing diameters D2_1, D2_2. The second group preferably therefore consists of at least two sub-groups of through openings that differ by a diameter D2_1, D2_2 of the cross-sectional area. Owing to the realization with two differing diameters D2_1, D2_2, a maximum possible suction cross section can be easily realized, while at the same time minimizing a loss of connection area. In preferred embodiments, the diameter D2_1 of the cross-sectional area of a first sub-group of the second group is equal to or greater than the diameter D1_1 of the cross-sectional area of the through openings of the first group, and the diameter D2_2 of the cross-sectional area of a second sub-group of the second group is less than or equal to the diameter D1_1 of the cross-sectional area of the through openings of the first group. Preferably, in this case, the first sub-group comprises at least one through opening, preferably three through openings, the diameter D2_1 being, particularly preferably, between 70% and 105%, ideally approximately 100% of the diameters of the suction holes of the abrasive-means carrier. Additionally or alternatively, the second sub-group can comprise at least two through openings, preferably four through openings, the diameter D2_2 being, particularly preferably, between 50% and 85%, ideally approximately 60% to 80% of the diameters of the suction holes of the abrasive-means carrier, and being not greater than the diameter D2_1 of the first sub-group.
Moreover, advantageous abrasive means according to the disclosure can be achieved in that the cross-sectional area of the through openings of the third group are circular and have at least one, preferably two, differing diameters D3_1, D3_2, the second group preferably therefore consisting of at least two sub-groups of through openings that differ in a diameter D3_1, D3_2 of the cross-sectional area.
It is also advantageous to limit the number of through openings of the third group, whereby the maximum possible suction cross section can be realized, while at the same time minimizing a loss of connection area. Preferably, for this purpose, the third group comprises five or six through openings.
Exemplary embodiments of the disclosure are represented in the drawings and explained in greater detail in the following description. In the drawings:
a shows an orbital sander as an example of a known abrasion appliance for the use of exchangeable abrasive means;
b shows a schematic plan view of the arrangement of the suction holes of a known abrasive-means carrier according to
c shows a known abrasive disc according to U.S. Pat. No. 5,989,112 and its disposition on an abrasive-means carrier according to
Table 1 summarizes the main key data of the preferred exemplary embodiments according to
a shows, exemplarily, a known abrasion appliance 10, designed as an orbital sander, having a housing 12 that, in the direction of view to the left, has a horizontal handle 14, which carries a manually operable switch button 16 of a switch, not represented, for starting and stopping the motor 20.
An electric cable 18, which serves to supply the motor 20 with energy, emerges at the rear end of the handle 14.
The housing 12 carries the motor 20 with a motor axis 19 that extends perpendicularly in relation to the handle 14 and in the downward extension of which a motor shaft 22 projects out of the motor 20. The end of the motor shaft is encompassed in a rotationally fixed manner by a cooling ventilator 26, which conveys air radially outward, in the direction of the cooling exhaust-air arrow 48. As a result, in the upper region of the housing 12, at cooling slots 23 of the housing 12, there is an intake of cooling external air, which can flow into the housing 12 and past the motor 20, according to the cooling inflow arrow 24, and can then leave the housing 12 through a connecting channel 46, via the suction stub 42.
Since the connecting channel 46 widens radially, in particular in the region of its opening 47 into the suction stub 42, the cooling exhaust air flows along the directional arrow 48 and generates an additional negative pressure—as with an injector pump—in the dust suction channel 40. This results in an intensified discharge of ground-off material from suction holes 38, realized in the abrasive-means carrier 34, which is realized as a backing pad, toward the dust box 50.
The housing 12 surrounding the cooling ventilator 26 is sealed in the axially downward direction, and has the lower end of the motor shaft 22 extending through it. The latter is rotatably mounted there in a roller bearing 28.
In the bell-type region that faces away from the cooling ventilator 26, the free end of the motor shaft 22 carries a dust ventilator 30, which sucks in dust and ground-off material, through the suction holes 38 realized in the abrasive-means carrier 34, and blows this air and material out to the suction stub 42.
An annular sealing lip 52 seated at the lower edge of the housing 12 is supported, so as to be resiliently biased in the axial direction, on the top of the abrasive-means carrier 34. As a result, the space between the housing 12 and the abrasive-means carrier 34 is sealed off against disturbing infiltrated air, and the removal of ground-off material is rendered highly efficient.
Downwardly, toward the abrasive-means carrier 34, the dust ventilator 30 has an eccentric opening, not designated in greater detail, which serves as a bearing seat for a ball bearing 31. This eccentrically seated ball bearing 31 carries an eccentric pin 32, which can be connected to the abrasive-means carrier 34 in a rotationally fixed manner by means of a screw 36.
When the motor shaft 22 rotates, the eccentric 32 follows this rotation, because of the bearing friction of the ball bearing 31, in that it rotates about its eccentric axis 33 and, at the same time, orbits about the motor axis 19, or the motor shaft 22. This results in the characteristic orbital, oscillating motion of the abrasive-means carrier 34 that is usual in the case of orbital sanders.
The abrasive-means carrier 34 of the known abrasion appliance 10 is mounted/mountable at least on a fastening surface 90 that faces away from the abrasion appliance 10 and that preferably has attachment means, not represented in greater detail here, for exchangeably fastening abrasive means 100, 200 to the abrasive-means carrier 34. Persons skilled in the art are familiar with a very great variety of attachment means for this purpose, from which they may select according to the intended application of the abrasion appliance 10 and the anticipated demands upon the abrasion appliance 10, without this selection affecting the character of the present disclosure. Particularly common attachment means are, on the one hand, realization with catching hooks, as a catching surface, or, alternatively, design as a flat adhesive plate for fastening exchangeable abrasive means by adhesion. Also possible, however, are other adhesive fastening methods such as, for example, electrostatic attachment by means of a fastening surface 90 realized as an electrostatic attachment plate, or other attachment means familiar to persons skilled in the art. Alternatively or complementarily, a clamping device may be provided on the abrasive-means carrier 34, for the purpose of fixing the exchangeable abrasive means.
An exchangeable abrasive means 100, 200 in this case preferably has at least a two-layer, or two-ply, structure. The first layer, which, when correctly attached to the abrasive-means carrier 34, faces toward the latter, is in this case realized as a fastening layer 102, 202, and preferably has fastening means that correspond to the attachment means on the fastening surface 90 of the abrasive-means carrier 34. In a preferred embodiment, the fastening layer 102, 202 is realized as a hook/loop fleece; particularly preferably, the fastening layer is composed substantially of the hook/loop fleece. In another known embodiment, the fastening layer 102, 202 is realized as a pressure-sensitive adhesive system, which preferably comprises a pressure-sensitive adhesive layer, and particularly preferably is substantially composed of the latter. Frequently, when realized as a pressure-sensitive adhesive system, fastening layers 102, 202 additionally have on their surface a detachable protective film, which serves substantially to protect the adhesive layer, and which, accordingly, must be pulled off before the exchangeable abrasive means 100, 200 is applied to the abrasive-means carrier 34.
The second layer 104, 204, which is substantially opposite the first layer, comprises a working ply; preferably, the second layer 104, 204 is composed substantially of the working ply. In a preferred embodiment of the working ply, the latter is realized as an abrasion ply, wherein an abrasion ply is understood to mean, in particular, a ply or ply system that has at least abrasive particles, in particular sanding particles.
b shows a schematic plan view of the fastening surface 90 of the abrasive-means carrier 34, wherein represented the position of suction holes 38, 38a, 38b of two known, very common configurations.
The first, radially more outer configuration represents the five-hole version of suction holes 38a that was mentioned at the outset. In this case, the suction holes 38a are disposed on a first hole-circle diameter 70a. In a preferred embodiment, the hole-circle diameter 70a is between 67 and 75 mm, preferably approximately 72 mm. Preferably, the five suction holes 38a.1 to 38a.5 in this case are disposed with a uniform angular spacing WA1 on the first hole-circle diameter 70a. In particular, the suction holes 38a are circular in form, and have a first diameter DA1. In a preferred embodiment, the diameter DA1 of the suction holes 38a in this case is between 6 and 12 mm, in particular between 8 and 11 mm, particularly preferably approximately 10 mm.
The second, radially more inner configuration represents the eight-hole version of suction holes 38b that was mentioned at the outset. In this case, the suction holes 38b are disposed on a second hole-circle diameter 70b. In a preferred embodiment, the hole-circle diameter 70b is between 60 and 67 mm, preferably approximately 65 mm. Preferably, the eight suction holes 38b.1 to 38b.8 in this case are disposed with a uniform angular spacing WA2 on the second hole-circle diameter 70b. In a preferred realization, the suction holes 38b are circular in form, and have a second diameter DA2, the diameter DA2, particularly preferably, being substantially equal to the diameter DA1. In a preferred embodiment, the diameter DA2 of the suction holes 38b in this case is between 6 and 12 mm, in particular between 8 and 11 mm, particularly preferably approximately 10 mm.
A known abrasive disc 100 according to U.S. Pat. No. 5,989,112, as an example of an exchangeable abrasive means, and its disposition on an abrasive-means carrier 34 according to
According to U.S. Pat. No. 5,989,112, the eccentricity of the through openings 110.1, 110.3, 110.4, 110.6 and 110.7, realized as elongated holes i.e. the distance from the first to the respective second center point of the semicircles delimiting the respective elongated hole, is determined in that these center points are disposed on a circumcircle diameter 120a, which is substantially the same as the hole-circle diameter 70a, in such a manner that, when the abrasive disc 100 is disposed in the correct position on a five-hole version abrasive-means carrier 34, the through openings 110.1, 110.3, 110.4, 110.6 and 110.7 the elongated holes of the through openings 110.1, 110.3, 110.4, 110.6 and 110.7 almost completely overlap the suction holes 38a.1 to 38a.5 respectively assigned to them. A centroid 130.1, 130.3, 130.4, 130.6 and 130.7—in
In respect of a radial disposition of the through openings 210A.1-210A.12, three groups of through openings can be distinguished in the preferred example according to
In this case, the centroids 230A.3 and 230A.11 of two through openings 210A.3 and 210A.11 are disposed on a first circumcircle 220Aa, the diameter of which preferably corresponds substantially to the hole-circle diameter 70a of the five-hole version abrasive-means carrier 34. In a particularly preferred embodiment, the centroids 230A.3 and 230A.11 are in this case disposed on the first circumcircle diameter 220Aa in such a manner that, when the exchangeable abrasive means 200A is correctly disposed, or disposed in the correct position, on a five-hole version abrasive-means carrier 34, they can be made to substantially overlap the center points of the suction holes 38a.2 and 38a.5. The through openings 210A.3 and 210A.11 thus constitute a first group 240A of through openings 210A. Preferably, in this case, a diameter D1_1 of the circular cross-sectional areas of the through openings 210A.3 and 210A.11 corresponds to the diameter DA1 of the suction holes 38a. In a preferred embodiment, the diameter D1_1 of the through openings 210A.3 and 210A.11 of the first group 240A is between 6 and 12 mm, in particular between 8 and 11 mm, particularly preferably approximately 10 mm.
A second group 250A of through openings is distinguished in that their centroids are disposed on a second circumcircle diameter 220Ab, the diameter of which preferably corresponds substantially to the hole-circle diameter 70b of the eight-hole version abrasive-means carrier 34 version. In the preferred embodiment according to
Provided in the embodiment according to
Furthermore, with the through opening 210A.1, the third group 260A comprises a fifth element, whose centroid 230A.1 is disposed between the circumcircle diameters 220Aa, 220Ab in such a manner that, depending on the hole version of the abrasive-means carrier 34, at least 50%, preferably at least 70%, in particular preferably at least 80% of a cross-sectional area of the through opening 210A.1 can be overlapped, either by the suction hole 38a.1 or by the suction hole 38b.1. In particular, the centroid 230A.1 in this case lies on a circumcircle diameter that preferably corresponds substantially to a mean value of the circumcircle diameters 220Aa and 220Ab. In a preferred embodiment according to
A first group 240B of through openings is distinguished in that their centroids are disposed on a circumcircle diameter 220Ba, the diameter of which preferably corresponds substantially to the hole-circle diameter 70a of the abrasive-means carrier 34 in the five-hole version. In the preferred embodiment according to
In this example, a second group 250B comprises the five through openings 210B.3, 210B.5, 210B.8, 210B.11 and 210B.13, whose centroids 230B.3, 230B.5, 230B.8, 230B.11 and 230B.13 are disposed on a circumcircle diameter 220Bb that is substantially identical to the hole-circle diameter 70b. In the preferred embodiment according to
According to
The remaining two through openings 210B.1 and 210B.2 of the third group 260B of the exemplary embodiment according to
A further preferred embodiment of the disclosure is represented in
In this case, the centroids 230C.3 and 230CA.11 of two through openings 210C.3 and 210C.11 are disposed on a first circumcircle diameter 220Ca, the diameter of which preferably corresponds substantially to the hole-circle diameter 70a of the abrasive-means carrier 34 in the five-hole version. In a particularly preferred embodiment, the centroids 230C.3 and 230C.11 are in this case disposed on the first circumcircle diameter 220Aa in such a manner that, when the exchangeable abrasive means 200A is correctly disposed, or disposed in the correct position, on a five-hole version abrasive-means carrier 34, they can be made to substantially overlap the center points of the suction holes 38a.2 and 38a.5. The through openings 210C.3 and 210C.11 thus constitute a first group 240C of through openings 210C. Preferably, in this case, a diameter D1_1 of the circular cross-sectional areas of the through openings 210C.3 and 210C.11 is smaller the diameter DA1 of the suction holes 38a. In a preferred embodiment, the diameter D1_1 of the through openings 210C.3 and 210C.11 of the first group 240C in this case is between 4 and 9 mm, in particular between 5 and 7 mm, particularly preferably approximately 6 mm.
A second group 250C of through openings is distinguished in that their centroids are disposed on a second circumcircle diameter 220Cb, the diameter of which preferably corresponds substantially to the hole-circle diameter 70b of the abrasive-means carrier 34 in the eight-hole version. In the preferred embodiment according to
According to
Further, with the through opening 210C.1, the third group 260C comprises a fifth element, whose centroid 230C.1 is disposed between the circumcircle diameters 220Ca, 220Cb in such a manner that the cross-sectional area of the through opening 210C.1 fills to at least 50%, preferably to at least 70%, in particular preferably to at least 80%, a common intersecting area formed by notional overlapping of the suction holes 38a.1 and 38b.1. In a preferred embodiment according to
Unlike the exemplary embodiment according to
Table 1 summarizes the main key data of the preferred exemplary embodiments according to
Persons skilled in the art may achieve further embodiments according to the disclosure by, in particular, appropriately combining the features of the previously described embodiments. Persons skilled in the art may achieve further embodiments according to the disclosure by realizing the cross-sectional areas of at least one of the groups of through openings so as to be non-circular; thus, for example, triangular, square or higher-polygonal contour forms may be advantageous realizations of through openings within the meaning of the disclosure. Preferably, such contours of through openings can be made in a prefabricated abrasive means by machining operations of punching or cutting such as, for example, laser cutting. In particular, however, the disclosure is not limited to abrasive discs, in particular thin, flexible abrasive discs, but may also be advantageously applied with other exchangeable abrasive means, known to persons skilled in the art, for driving by means of abrasive-means carriers described at the outset.
Number | Date | Country | Kind |
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10 2012 214 382.3 | Aug 2012 | DE | national |