EP3334563B1 - Grinding disc and grinding machine provided with same - Google Patents

Description

The invention relates to a grinding plate for a grinding machine, the grinding plate having a machine side assigned to the grinding machine and a processing surface assigned to machining a workpiece, according to the preamble of claim 1.

Such sanding pads are for example in U.S. 3,315,420 A , DE 299 13 046 U1 , GB 753,938 A and WO 03/002304 A1 described.

A sanding plate is usually designed for processing a flat or planar surface of a workpiece. The sanding pad has a plate-like or plate-like shape, i.e. it is particularly suitable for flat surfaces.

For special purposes, grinding plates are known which have a special profile, for example a grinding plate DE 101 44 274 A1 for processing formed surfaces. An increased grinding effect in the central area of a grinding plate is in DE 32 40 917 explained.

For processing a flat workpiece with a grinding machine, the housing of which can be grasped directly by hand, the known grinding plates can be used without further ado. In grinding machines with a handle, in particular ceiling grinding machines and wall grinding machines, such grinding plates are difficult to guide. The relatively large distance between the grip area on the grip rod and the processing surface of the grinding plate creates force relationships that are difficult for the operator to handle.

To solve the problem, a sanding pad according to the technical teaching of claim 1 is provided.

At the edge area, the sanding pad rotates at a higher peripheral speed, which among other things also contributes to a higher removal rate or abrasion rate.

For example, the abrasive in the central area is not in contact or is only in lightly rubbing contact with the workpiece. It is preferably provided that the contact pressure in the edge area of the processing surface in the direction of the workpiece is approximately 1.5 times to 2 times greater, preferably approximately three times greater or four times greater than in the central area. It is preferred that about 70-80%, preferably about 80-90%, even more preferably about 90-95% of the abrasive power of the abrasive is provided in the edge area of the processing surface, the remaining abrasive power of the abrasive in the central area.

It is a basic idea that the ring-shaped edge area represents, so to speak, the actual processing area of the abrasive, with which the workpiece can be abrasively processed. The central area, on the other hand, is ineffective with regard to the workpiece machining by the abrasive or at least effective to a lesser extent, expediently essentially ineffective, so that no forces or small forces from the central area on the tool holder and thus, for example, on the handle or other The gripping area of the grinding machine. The grinding machine can be optimally held and guided. The sanding pad can be guided smoothly and evenly over the workpiece surface to be processed.

The abrasive can be arranged directly on the processing surface or form the processing surface. For example, an abrasive coating can be provided directly on the grinding plate. The processing surface can therefore have, for example, the abrasive coating which, for example, comprises or is formed by abrasive grain and / or an abrasive knitted fabric.

However, it is also possible for the abrasive to be releasably attachable to the sanding plate so that it can be removed, for example, when worn, and exchanged for another abrasive.

The abrasive is expediently designed as a sanding sheet or sandpaper. The abrasive can, however, also be or have an abrasive knitted fabric.

The holding means comprises, for example, Velcro holding means in the manner known per se, for example corresponding Velcro hooks. It is also possible, however, for the holding means to comprise an adhesive or similar other releasable connecting means between the grinding means and the grinding plate.

An abrasive that can be detached from the sanding pad can also form an in particular integral part of the sanding pad. It is therefore conceivable that the action of the grinding plate occurs in conjunction with the grinding means.

The grinding plate can be designed so that the grinding means is always in contact with the workpiece in the annular edge area of the grinding plate, but not in the central area. In the central area there is expediently a distance between the machining surface and the workpiece surface. For example, a bulge and / or a recess can be provided in the central area, which ensures or contributes to the grinding means in the central area has a distance to the workpiece or in any case develops a lower abrasive effect than at the edge area.

However, it is also possible to provide a central area that is more flexible than the edge area, for example a central area with a softer material than at the edge area, so that the contact pressure or effective force of the abrasive is lower in the central area than in the edge area.

The more flexible material can be provided in a plane directly next to the processing surface or on the processing surface. The processing surface, for example for carrying the abrasive, can be provided directly on the softer material of the central area or the harder material of the edge area. However, it is also possible that the softer material for the central area does not have the processing surface directly, but that, for example, a sandwich layer is provided between the processing surface and the material that is harder in the edge area and softer in the central area. The sandwich layer can be provided, for example, by a so-called pad or an elastic or soft cushion.

It goes without saying that a combination is also possible, i.e. that, for example, the central area of the processing surface is set back or recessed somewhat compared to the edge area or forms a cavity and, in addition, a softer, smaller compression modulus material is used in the central area than in the edge area. Both measures in combination contribute in any case to the fact that the grinding plate or the grinding means arranged on the grinding plate is not in abrasive contact with the workpiece to be machined in the central area or to a lesser extent than in the edge area of the machining surface.

According to the invention, the grinding means for machining the workpiece and / or the holding means for holding the grinding means extend essentially over the entire machining surface including its center. It is therefore a large area, uninterrupted or provided with a few interruptions Abrasive area or holding means area provided. The central area can also be used to process the workpiece using the abrasive.

The processing surface and / or the grinding means and / or the holding means expediently have air passages for supplying fresh air and / or removing exhaust air, for example exhaust air laden with dust. It is preferably provided that the air passages of the grinding means and the processing surface communicate with one another, so that air laden with dust can flow from the workpiece surface through the grinding means to a side of the grinding plate facing away from the processing surface, for example its upper side. The air passages therefore expediently extend from the processing surface to a top side or rear side of the grinding plate facing away from the processing surface.

A preferred concept provides that the air passages are arranged in a ring around a central axis of the grinding plate. One or more rings can be provided. The rings are preferably arranged concentrically around the central axis.

It is also preferred if some of the air passages are closer to an inflow opening of a dust removal device of the sanding device during operation of the sanding plate, so that supply air flows through air passages further away from the suction opening into the sanding plate, in particular up to the processing surface and / or to the holding means, transversely to the processing surface, for example, the holding means and / or the processing surface, in particular the surface facing the workpiece or the surface provided with abrasive material, flows through and then flows out through air passages which are each closer to the intake opening. The role of the air vents naturally changes as the sanding pad rotates. A transverse flow is thus advantageously generated, in particular in the area of the processing surface or the holding means, so that this does not or less clogged with dust. In particular, this cross flow is in the Central area of the sanding plate is provided, where there is therefore as little pressure or contact pressure as possible in the direction of the processing surface.

It can optionally be provided that such air passages or air inlets for discharging dust-laden air are only provided in the central area of the sanding plate. It is furthermore possible that the air passages have a radial component, i.e. that they comprise, for example, air ducts which extend from the central area radially outwards to the top or rear of the grinding plate, where the suction device acts. Of course, suction openings or suction openings can also be provided in the edge area or exclusively in the edge area. Both are therefore possible, namely suction openings only at the edge area of the processing surface or only in the central area or both at the edge area and in the central area. If suction openings or air passages are also or only provided in the central area, a type of suction bell is created on the processing surface, for example.

According to the invention, the processing surface and / or the grinding means and / or the holding means have no interruptions apart from the air passages or air inlets.

The processing surface and / or the grinding means and / or the holding means are expediently designed and / or provided for flat contact with the workpiece.

A preferred concept provides that slots or interruptions or deformation contours or combinations thereof are provided on the processing surface and / or the grinding means and / or the holding means, which ensure a flat position of the processing surface, in particular the edge area thereof, on the workpiece when the processing surface is deformed from a state unloaded by the contact pressure to a state loaded by the contact pressure. In particular, a flat position in the form of a ring around a central axis of the sanding plate is preferred. By means of these measures, for example, a so-called vertical runout or horizontal runout can be avoided.

The slots or interruptions widen or give way, for example when deformed by the contact pressure. The deformation contours can include, for example, wave-shaped indentations, joints or the like. In any case, the processing surface or the grinding means or the holding means becomes flexible in the sense of deformability, in particular uniformly flexible, if the deformation contours, slots or interruptions or combinations thereof are provided.

The slots and / or interruptions and / or deformation contours advantageously have a longitudinal shape.

The slots and / or interruptions and / or deformation contours are particularly advantageous in relation to a central axis of the sanding plate, radially or in a star shape. As a result, the sanding pad can, for example, be deformed in the manner of a bell in the unloaded state by the contact pressure, while it can then be pressed flat, so to speak, when the contact pressure is loaded and the deformation contours, slots or interruptions ensure the corresponding flexibility.

Interruptions, deformation contours or slits are particularly preferred in the holding means, for example if this comprises fibers or a fabric structure. For example, a Velcro or Velcro layer produced on a textile basis or fiber basis or fabric basis can be provided as the adhesive, which, however, is more tensile with regard to the warp and weft or at least the direction of their fibers than transversely to them. A Velcro fabric, for example, has different stiffnesses in the weaving direction or transversely to the weaving direction, which leads to different forces in the Velcro layer when heated. The deformation contours make it possible for these fibers to be variable in length with respect to their longitudinal direction. The interruptions and / or slits make it possible for these fibers to be interrupted and, accordingly, for the adhesive or the Velcro layer to be more easily deformable or more flexible.

The slots, interruptions and deformation contours or combinations thereof are preferably particularly advantageous in the annular edge area, at least in the area that is in abrasive contact with the workpiece during typical workpiece machining. If the slots, interruptions or deformation contours are provided in the adhesive layer, the abrasive, for example, can again be continuous, i.e. have no interruptions or slots, so that it rests flat on the workpiece.

A measure that is in combination with the previous measures or that is independent per se advantageously provides that the holding means comprises a film or an extrusion Velcro. It is also useful if the holding means does not contain any fibers. All these measures contribute to a uniform deformability of the holding means, so that it yields evenly when loaded by the contact pressure over the circumference (i.e. in the circumferential direction around the center axis of the grinding plate) and / or forms a continuous flat surface when it rests on the workpiece. This counteracts or avoids a so-called vertical runout or horizontal runout of the sanding plate.

The extrusion Velcro is, for example, significantly more temperature-stable and does not deform or deform only insignificantly in the event of low heating, for example in a range of up to 60 °. There is thus no fear of deformation of the Velcro, neither during operation of the sanding plate nor during storage, or at least no uneven deformation, which counteracts a wobble.

For example, the film can be an extrusion film or an adhesive film. For example, the extrusion film or adhesive film can also represent an intermediate layer which is provided between the holding means and an elastic cushion.

It is preferred that the film or extrusion Velcro is connected to an elastic cushion of the sanding plate by means of an adhesion promoter film. The cushion can, for example, first be provided with the adhesion promoter film, to which in turn the film or extrusion Velcro is attached or glued. Alternatively, it is also possible for the elastic cushion, for example a corresponding foam, to be attached or foamed to the film or extrusion Velcro by means of foaming.

Furthermore, it counteracts vertical run-out or axial run-out if the following is provided:
An expedient measure provides that no component or at most a support plate which carries soft components of the sanding plate (for example elastic cushion or adhesive or both) contains fibers. In particular, it is advantageous if no component or only the support plate contains fibers running transversely to the processing surface. It is therefore possible that fibers are present in such components or in the grinding plate, but which do not run transversely to the processing surface or parallel to the processing surface. Such fibers do not prevent deformation of the sanding plate when it is loaded by the contact pressure in the direction of a flat position on the workpiece.

It is expediently provided that the processing surface has a step and / or an inclined surface, for example a conical inclined surface, between the edge area and the central area, so that a depression, for example a trough, is formed in the central area.

The central area can also have a flat surface or a flat surface. For example, it is possible that the central area has an inclined surface or step radially on the outside, or both, to the edge area in, wherein the inclined surface or step is then provided between the edge area and the inner area of the central area and this inner area is planar or flat.

The tool holder can, for example, have an opening for a screw bolt, so that the grinding plate can be mounted on a tool holder of the grinding machine that has a screw projection or screw bolt. It is also possible that the tool holder, for example, form-fit contours, in particular screw contours or includes bayonet contours for screwing in the tool holder. Of course, the tool holder can also comprise a screw bolt or some other fastening projection.

The mechanical structure of the sanding plate can be designed in various ways, which will become clear below.

A preferred embodiment of the invention provides that the sanding plate has a support plate on which an elastic cushion or pad is arranged. The backing pad has the machine side. The side of the support plate facing away from the cushion or pad expediently forms the machine side. The processing surface is provided on the side of the cushion facing away from the support plate. The processing surface can be provided integrally on the cushion. However, it is also possible for the processing surface to be provided on a further layer arranged on the cushion. The cushion is preferably firmly connected to the support plate, for example glued and / or welded to it. A mechanical connection, for example jamming, between the support plate and the cushion is also possible.

The tool holder, for example, is arranged on the support plate. The tool holder can form an integral part of the support plate or be attached to it.

The cushion forms, for example, a so-called pad or has a pad. The cushion or pad expediently consists of an elastic foam or plastic or has such a material. The cushion or pad can also consist of rubber or have rubber.

A holding area of the support plate facing the processing surface for holding the cushion has, for example, a support edge area which is assigned to the edge area of the processing surface or the grinding means, and a support central area which is assigned to the central area of the processing surface. The support edge area protrudes further in the direction of the processing surface than the support central area. Alternatively or in addition, it is also possible that the Support plate is somewhat less rigid in the central area than in the support edge area. The supporting edge area is accordingly stiff and not very flexible, so that it supports the abrasive better at its edge area than in the central area.

Thus, the supporting edge area contributes to this or forms the necessary measure that the edge area of the grinding means for abrasive machining of the workpiece is loaded in the direction of the workpiece or is in contact with the workpiece. The central support area, on the other hand, can for example have a recess or an inward curvature in a sense away from the machining surface, so that the central region of the machining surface is less heavily loaded or not at all in the direction of the workpiece.

A cushion can be arranged on such a support plate, for example, the material thickness of which is the same or at least substantially the same in the edge area and central area. The sanding pad according to the invention preferably has such a pad. The measures for forming the planar edge area are, so to speak, provided by the support plate.

It is preferably provided that a material thickness of the cushion or the support plate or both in the edge area and in the central area is essentially the same or even exactly the same. The support plate or the cushion are so to speak of the same thickness both in the edge area and in the central area.

It is possible for a material thickness of the cushion and / or the support plate to be the same or essentially the same over the projection surface of the processing surface.

Nevertheless, it is possible for the properties according to the invention to be achieved, for example, due to different compression modules. Furthermore, the geometric variations, namely that the edge area protrudes further towards the workpiece than the central area, at least when the sanding pad is loaded, can be achieved by, for example, a pad with the same material thickness over the entire cross-section or in the edge area and central area the support plate which has a geometric shape such that the edge area protrudes further towards the workpiece to be machined than the central area.

However, it is also possible that a material thickness of the cushion or support plate varies and the following variant can nevertheless be implemented: a distance between an underside of the cushion or the support plate or both facing the processing surface and the processing surface in the edge area and the central area is essentially the same or even is exactly the same.

The central support area and the edge support area can merge continuously. For example, an inclined surface, in particular a conical inclined surface, is provided between the support central area and the support edge area.

However, it is also possible for at least one step to be provided between the central support area and the edge support area.

It is possible for a step and an inclined surface to be present between the support central area and the support edge area.

In any case, it is advantageous if the central support area has a depression, in particular a trough, opposite the support edge area.

It goes without saying that such a configuration is also possible with the cushion. The cushion expediently protrudes on its underside facing the processing surface or the underside forming the processing surface further towards the processing surface or at least further in the direction of the workpiece than in the central area. For example, a depression, in particular a trough, is formed on this side of the cushion. A step, inclined surface or both is expediently provided between the central area and the edge area of the aforementioned underside of the cushion.

The grinding plate as a whole can have a concave shape in the area of the machining surface, so that the central area is curved away from the work surface or workpiece surface.

However, it is also possible for the support plate to have a concave holding area for the cushion and / or the cushion on its machining surface provided for machining the workpiece.

At least one air passage for a fresh air stream or a dust-laden dust air stream is expediently provided in the central area of the grinding plate, the at least one air passage extending between the processing surface and the machine side. Thus, for example, dust air can be sucked off on the machine side facing away from the machining surface and / or fresh air can be supplied to the machining side.

The at least one air passage expediently forms part of an arrangement of several air passages, for example ring-shaped, linear, star-shaped or similar air passages arranged next to one another. It is also conceivable that air passages with different functions are provided, of which at least one air passage is provided for supplying fresh air and another air passage is provided for removing dusty air.

The sanding plate is expediently essentially circular. In particular, it is advantageous if the machining surface represents an annular surface. Of course, the approach according to the invention can also be used with non-circular sanding discs.

An area ratio between the edge area and the central area is, for example, approximately three to one or two to one. An area of the edge area is therefore, for example, two to three times larger than an area of the central area. However, in relation to its area, the edge area can also be, for example, only 1.5 times as large as the central area. It is also conceivable that the central area is significantly smaller, so that, for example, an area of the edge area is between 3.5 times and four times larger than an area of the central area.

Furthermore, it is possible that the grinding means can move freely away from the workpiece to be machined at the radially outermost section of the edge region, which is advantageous, for example, in certain workpiece machining operations. However, the outer circumference area can also be curved in one sense away from the surface of the workpiece to be machined or have a step or both. This measure also works in the aforementioned sense. This measure can, for example, contribute to the fact that so-called grooves or other irregularities do not occur on the ground surface of the workpiece or are present to a lesser extent.

As mentioned, the abrasive can, for example, be plate-like or disk-like, for example comprise an abrasive sheet.

It is preferably provided that a contour of the grinding means is adapted to a contour of the machining surface, so that, for example, the grinding means has a depression in the central area of the machining surface.

It is possible that the abrasive spans part of the central area at a distance from the processing surface. For example, it is possible for the abrasive to bridge a depression or depression in the central area. The abrasive sheet or abrasive can move away from the workpiece or be displaced into this trough in a sense. This reduces the abrasive effect of the abrasive.

The abrasive has, for example, a projection surface that corresponds to that of the processing surface. The abrasive can therefore cover the entire processing surface, including the central area.

The abrasive is circular, for example.

It is expediently provided that the abrasive is only in contact with the workpiece in the edge area when the workpiece is being machined, while there is a distance between the abrasive and the workpiece in the central area. This situation is given in particular when the workpiece is essentially planar or flat. Thus, there is no abrasive machining of the workpiece in the central area. If the workpiece has a bulge or a hill, it can at least partially engage in the central area, so that at least brief abrasive contact between the central area and the workpiece surface is possible. The normal situation, however, will be that in the case of a flat or planar workpiece surface, the central area of the processing surface or the grinding means arranged there has no contact with the workpiece surface.

The workpiece can be, for example, the wall of a building or a room, but also a mobile workpiece, for example a wooden element, a building board, a piece of furniture or the like.

Figur 1

eine perspektivische Schrägansicht eines ersten Schleiftellers von schräg unten, der in

Figur 2

im Querschnitt entlang einer Schnittlinie A-A in Figur 1 dargestellt ist,

Figur 3

den Schleifteller gemäß Figuren 1, 2 von schräg oben,

Figur 4

eine perspektivische Schrägansicht eines zweiten Schleiftellers von schräg unten, der in

Figur 5

im Querschnitt entlang einer Schnittlinie B-B in Figur 4 dargestellt ist,

Figur 6

den Schleifteller gemäß Figuren 3, 4 von schräg oben,

Figur 7

einen dritten Schleifteller perspektivisch von schräg unten, der in

Figur 8

im Querschnitt entlang einer Schnittlinie C-C in Figur 7 dargestellt ist,

Figur 9

den Schleifteller gemäß Figuren 7, 8 von schräg oben,

Figur 10

eine schematisch dargestellte Schleifmaschine bei der Nutzung eines der Schleifteller gemäß Figuren 1-9 zur Bearbeitung einer Wandfläche oder einer Deckenfläche,

Figur 11

einen weiteren Schleifteller mit Schlitzen an seinem Haltemittel, und

Figur 12

ein schematisch angedeutetes Verfahren zur Herstellung eines Schleiftellers oder dessen Bestandteilen.

In the following, exemplary embodiments which do not correspond to the subject matter of the invention according to the appended claims are explained with reference to the drawing. Show it:

Figure 1

a perspective oblique view of a first sanding plate obliquely from below, the in

Figure 2

in cross section along a section line AA in Figure 1 is shown

Figure 3

the sanding pad according to Figures 1, 2 from diagonally above,

Figure 4

a perspective oblique view of a second sanding plate obliquely from below, the in

Figure 5

in cross section along a section line BB in Figure 4 is shown

Figure 6

the sanding pad according to Figures 3 , 4th from diagonally above,

Figure 7

a third sanding pad in perspective from diagonally below, which is shown in

Figure 8

in cross section along a section line CC in Figure 7 is shown

Figure 9

the sanding pad according to Figures 7, 8 from diagonally above,

Figure 10

a schematically shown grinding machine when using one of the grinding plates according to FIG Figures 1-9 for processing a wall surface or a ceiling surface,

Figure 11

another sanding pad with slots on its holding means, and

Figure 12

a schematically indicated process for the production of a sanding plate or its components.

A grinding machine 90 has a grinding head 91 on which a tool holder 92 for grinding plates 10, 110, 210 is arranged. The tool holder 92 can be driven by a drive motor 93 which is arranged, for example, on the grinding head 91, in particular the housing 94, or on a handle 96 of the grinding machine 90. The drive motor 93 drives the tool holder 92 directly or via a gear 95 at least rotationally and / or eccentrically. The drive motor 93 forms part of a drive unit 93A. If necessary, the transmission 95 is also contained in the drive unit 93A. Preferred At least one rotary component is present, so that the sanding plate 10, 110, 210 is driven or drivable exclusively in a rotary or rotary manner with, for example, a so-called hypercycloid or other superimposed movement.

The grinder 90 is a hand-held grinder. In principle, it is conceivable that the grinding machine 94 is grasped and guided directly on its housing 94, for example a handle area 99. In this way, for example, a wall surface W could be sanded at least at a standing height of a user, for example in a lower area of the wall surface W close to the floor. However, sanding a ceiling surface D would be cumbersome. The grinding machine 90 therefore has an elongated handle 96 so that, for example, grinding overhead or in an area that is further away from the user of the grinding machine 90 is easy. The ceiling surface D or the wall surface W form workpiece surfaces of a workpiece generally referred to as workpiece V, for example.

The handle 96 comprises, for example, a handle bar 98 which is articulated at least pivotably to the grinding head 91 via a joint 97. Thus, the grinding head 91 can pivot relative to the handle bar 98, which facilitates its positioning relative to the surface to be ground. Certain repercussions on the housing 94 and thus ultimately also on the handle 96 occur from the sanding plate 10, 110, 210. Such repercussions are, however, minimized or even avoided by the grinding plates 10, 110, 210.

The grinding plates 10, 110, 210 each have a machine side 11 facing the grinding machine 90 and a processing surface 12, 112, 212 facing away from the machine side 11 and facing the workpiece surface to be processed, for example the wall surface W or the ceiling surface D.

The machine side 11 is provided on a support plate 13, 113, 213. The support plates 13, 113, 213 comprise plate-shaped support bodies 14, 114, 214, on the machine side 11 of which a tool holder 15 is provided.

The tool receptacle holder 15 comprises, for example, form-fit contours 16, for example bayonet contours or a screw thread, for attachment to the tool receptacle 92.

The tool holding fixture 15 comprises, for example, a receiving recess 22, although this is not to be understood as a restriction because, for example, a holding projection would also be possible, for example a screw pin.

A stiffening area 17 extends around the tool holder 15, so that the central area of the grinding plate 10, 110, 210 is relatively stiff in the center of the machine side 11. A stiffening projection 18 also extends on an outer circumference of the, for example, plate-like stiffening region 17.

It is possible that the stiffening area 17 is formed from a different material than the support body 14, 114, 214. For example, the stiffening area 17 is formed by a wall disk 19 which is located between a support projection 20 of the tool holder 15 and which is at a radial distance around the support projection 20 extending further stiffening projection 18 extends.

A flexibility or resilience of the grinding plate 10, 110, 210 can, however, be desired at certain points. For this purpose, for example, a groove 21 or some other recess is provided on the machine side 11.

A cushion 30, 130, 230 is arranged on an underside 23 of the support plate 13, 113, 213 which faces away from the machine side 11 and which could also be referred to as the fastening side. An upper side 31, which could also be referred to as the plate side, of the cushion 30, 130, 230 is firmly connected to a holding area 28 of the lower side 23, for example glued and / or welded to it or the like.

The machining surface 12, 112, 212 is provided on a lower side 32 facing away from the upper side 31. There is also on the processing surface 12, 112, 212 a holding means 33, for example an adhesive, in particular a Velcro layer 34, is provided for holding an abrasive means 50, for example an abrasive sheet 51.

On its fastening side or top facing the processing surface 12, 112, 212, the grinding means 50 has counter contours 52 suitable for the holding means 33, for example, a loop layer that is attached to the holding means 33, for example the Velcro layer 34, in the sense of holding the grinding means 50 on Cushions 30 or the processing surface 12, 112, 212 cooperate.

On the side facing away from the processing surface 12, 112, 212, the grinding means 50 have, for example, a grain size and / or an abrasive fabric and / or abrasive knitted fabric or similar other abrasive material 53 for abrasive processing a workpiece surface, for example the ceiling surface D or the wall surface W.

It is preferably provided that an area of the grinding means 50 corresponds approximately to the area of the processing surface 12, 112, 212. However, it is also possible that the grinding means 50 have a larger area, for example protrude radially outward beyond the machining surfaces 12, 112, 212.

Outer circumferential surfaces 35, 135, 235 of the cushions 30, 130, 230 can, for example, as in the case of the grinding plate 10, have an inclined section 36 and optionally also a cylindrical section 37, so that, for example, the processing surface 12 has a larger surface area than the underside 23 of the support plate 13, or also include only one cylindrical section 137, 237, so that, as in the case of the grinding plates 110 and 210, an area of the underside 23 of the support plate 113, 213 and an area of the processing surfaces 112, 212 are approximately identical.

The processing surfaces 12, 112, 212 each have an annular edge region 44, 144, 244 in which the processing surface 12, 112, 212 is essentially flat on the surface to be processed, for example the ceiling surface D or the wall surface W rests. The grinding means 50 is thus pressed flatly in the edge region 44 onto the workpiece surface to be processed, so that abrasive processing takes place there.

The edge areas 44, 144, 244 surround central areas 45, 145, 245, where no or only a slight abrasive treatment of the workpiece surface is provided. Thus, a contact pressure P, which is exerted on the tool holder 15 in the direction of the machining surface 12, 112, 212, essentially acts in the edge areas 44, 144, 244, so that there the grinding material 53 the workpiece V, for example the ceiling surface D or wall surface W, abrasively processed, for example grinds, while in the central area 45, 145, 245 in the case of the grinding discs 10, 210 there is a distance between the grinding material 53 and the workpiece surface to be processed and thus no abrasive processing of the workpiece surface, for example the ceiling surface D or wall surface W, takes place or a slight abrasive treatment, as for example in the case of the grinding plate 110.

In the central areas 45, 245 of the processing surfaces 12, 212, depressions or depressions 46, 246 are provided, into which the grinding means 50 can deform. The grinding means 50 is not supported in the area of the depressions 46, 246, so that the grinding material 53 in the central area 45, 245 is largely ineffective with regard to the abrasive machining of the workpiece V.

Different from what is shown in the drawing, but according to the invention, provision is made for the abrasive 50 to be held on the processing area 12, 212 over its entire surface, so that the recess 46, 246 is also present on the front or processing side of the abrasive 50. The grinding means 50 thus adopts the contour of the machining surface 12, 212. Thus, in this case, a distance 47, which is shown schematically in Figure 2 and Figure 9 is shown, between the grinding material 53 and a workpiece surface of the workpiece V, for example the ceiling surface D or the wall surface W, is present.

In the case of the grinding plate 10, the recess 46 is formed in that a material thickness 38 of the cushion 30 in the edge area 44 is greater than a material thickness 39 of the cushion 30 in the central area 45. Thus, for example, there is a distance between the underside 23 of the support plate 13 and the processing surface 12 in the edge area 44 greater than a distance between the underside 23 of the support plate 13 in the central area 45.

The central region 45 and the edge region 44 advantageously merge continuously into one another. For example, the central area 45 has an essentially planar or level inner area 48, which merges with conical inclined surfaces 49 into the edge area 44. However, it is also conceivable that a step 49A is provided between the inner area 48 and the edge area 44 (shown schematically).

In the case of the sanding pad 210, the pad 230 has a continuous material thickness 238. The recess 246 is formed in that the support pad 213 has a supporting edge area 24 which protrudes in front of a supporting central area 25. An inclined surface 26 is provided between the supporting edge area 24 and the supporting central area 25. In any case, the central support area 25 forms a recess 27. The cushion 230 is permanently deformed into this recess 27, so that its underside 32 and thus the processing side 212 has approximately the same contour as the underside 23 of the support plate 213.

The cushions 30, 130, 230 consist, for example, of an elastic material, in particular of a foam material, rubber or the like.

Thus, for example, the cushion 130, which is fastened to the support plate 113, can be deformed during the machining of the workpiece V in the direction of the support plate 113 (indicated in dashed lines).

The support plate 113 corresponds structurally to the support plate 213, that is, it has the recess 27. When the cushion 130 is relieved, as in FIG Figure 5 As shown, the machining surface 112 is essentially planar or flat.

The cushion 130 and thus the processing surface 112 can deform into the recess 27, which is a cavity in the not yet deformed cushion 130, when a load or contact pressure P acts in the direction of the workpiece V, whereby the central area 145 is deformed forms with little or no abrasive machining of the workpiece V, while the edge region 144 is supported by the supporting edge region 24, so that the grinding material 53 can machine the workpiece V in the edge region 145 with abrasive action.

A material thickness 138 of the cushion 130 is approximately the same over the entire processing surface 112. For example, the cushion 130 and the cushion 230 can be structurally identical. This makes the cushion 130, 230 particularly easy to manufacture.

However, the cushion 30 with the recess 46 can easily be produced with the different material thicknesses 38, 39, for example by injecting suitable plastic material into a corresponding mold.

Furthermore, it is possible, for example by using different plastics, foam materials or the like, to provide different compression modules for one of the cushions 30, 130, 230 and / or for one of the support plates 13, 113, 213.

For example, it is possible for the cushion 30 to have a foam material or other elastic material 40 with a greater compression modulus than a foam material or other elastic material 41 that is used in the central area 45 on the radially outside, in the edge region 44. The different materials 40, 41 in Figure 2 indicated.

It is an advantageous measure, for example, if a step 43 or a surface curved away from the processing surface 12, 112, 212 is provided on an outer circumference area 42, into which the grinding means 50 can deform (see FIG Figure 5 ).

In the case of the sanding plates 10, 110, 210, measures are also taken for effective dust extraction.

For example, an arrangement 70 of air passages 71 extends in a ring around the tool holder 15. The air passages 71 run from the machine side 11 to the machining surface 12, 112, 212 50, in particular coaxially or at least next to the air passages 71, likewise have openings or air passages 54.

Due to the recess 27 and / or the recess 46, it is particularly well possible that an air stream in the form of, for example, a fresh air stream and / or a dust air stream can flow through the air passages 71 between the workpiece surface to be machined and the machine side 11.

The grinding machine 90 preferably has a cover 94A under or within which the grinding plates 10, 110, 210 are arranged. The cover 94B is flow-connected to a suction device 94A, which sucks dust out of the cover 94B or its interior and thus also sucks dust which flows out of the air passages 71, for example. The dust removal device 94A is connected, for example, to a suction hose of a vacuum cleaner in order to suck off any dust that occurs when the workpiece V is machined.

Based on Figure 2 A particularly favorable flow concept becomes clear, in which it is provided that the dust removal device 94A is arranged eccentrically to a central axis M of the grinding plate 10, 110, 210, so that exhaust air AL is sucked out of the air passages 71 via air passages 71 located closer to the dust removal device 94A . A suction opening 94C of the dust removal device 94A is arranged eccentrically to the central axis M. The outlet AL flows as supply air ZL through air passages 71 into the grinding plate 10, 110, 210, which is further away from the dust removal device 94A. The supply air ZL flows as a cross flow QS advantageously between the grinding means 50 and the holding means 33 or through the holding means 33 from the inflow-side air passages 71 to the outflow-side air passages 71, so that the cross flow QS arises. The cross flow QS is provided in particular in the central support area 25.

The inner regions 48 have a diameter D1, for example, and the conical inclined surface regions including the inner region have a diameter D2. The central areas 45, 145, 245 thus have the diameter D2.

The essentially planar edge regions 44, 144, 244 have a diameter D3. The edge regions 44, 144, 244 are annular with an inner diameter D2 and an outer diameter D3.

For example, the diameter D3 is approx. 18-42 cm, while the diameter D2 is smaller, for example between 14 and 18 cm. The smaller inner diameter D1 is approximately in the range of 8-12 cm. This information is only to be understood as an example, but it makes it clear that an area of the edge area is generally greater than that of the central area, so that the abrasive effect is sufficiently ensured. Nevertheless, the grinding plates 10, 110, 210 show good grinding behavior and can be easily guided with the grinding machine 90.

The grinding sheet 51 or grinding means 50 can protrude beyond the outer circumference of the edge regions 44, 144, 244 or the grinding pads 10, 110, 210. The grinding sheet 51 or grinding means 50 can, for example, have a diameter D4. The diameter D4 can, for example, be about 0.5-1 cm larger than the diameter D3. It is possible that the sanding sheet 51 or sanding means 50 protrudes a few millimeters, for example 2-5 mm, radially outward in front of the sanding plate.

An in Figure 11 The illustrated sanding plate 310 corresponds essentially to the sanding plate 10 according to FIG Figures 1-3 and has, for example, the support plate 13 on its side that is not visible in the drawing Backing plate 13, a processing surface 312 of the grinding plate 310 is provided, which is designed for fastening the grinding means 50.

On the processing surface 312, the an annular edge area 344 and a central area 345 corresponding to the edge area 44 and the central area 45. In the central area 345, the workpiece surface of the workpiece V is slightly or less abrasively processed than in the edge area 344 when contact pressure P is applied to the in The support plate 13, which is not visible in the drawing, acts in the direction of the machining surface 312.

The holding layer provided on the processing surface 312 in the form of the holding means 344 comprises, for example, a Velcro layer 334, which has a fabric 360 with threads or schematically indicated fibers 361, 362. The fibers 361, 362 represent, for example, the warp and weft of the fabric 360, that is to say, for example, they are orthogonal to one another. In the event of deformation or thermal loading of the holding means 333 or the Velcro layer 334, an uneven deformation could occur due to the orientation of the fibers 361, 362, the effect of which, however, is prevented or avoided by, for example, providing slots 363 which are radially located on the Work surface 312 extend. The slots 363 run, for example, from the outer circumference of the machining surface 312 to the central axis M of the grinding plate 310. Thus, for example, in a grinding plate according to the invention, circular segments or angular segments of the machining surface are formed that can move relative to one another when the grinding plate is loaded by the contact pressure P.

In particular, a flatness or the avoidance of a vertical runout or runout in the edge region 344, where the main abrasive machining of the workpiece V takes place, is advantageous. Accordingly, it is also readily possible to provide, for example, shorter slots or interruptions 364 (indicated schematically) that extend only in the edge region 344 on the processing surface 312, in particular on the holding means 333.

Based on Figure 12 a further measure improving the flatness of a respective grinding plate on the workpiece surface is to be shown schematically when the grinding plate is loaded by contact pressure P in the direction of the machining surface or workpiece surface. For example, in a sanding plate 410 according to FIG Figure 12 , which is only indicated schematically, a holding means 433 is provided which comprises an extrusion Velcro 434. The extrusion Velcro 434 is produced, for example, from a film 433A, which is processed using a processing roller 490 to form an intermediate product 433B which comprises Velcro projections 435.

The Velcro projections 435 are formed, for example, by corresponding extrusion projections 491 of the roller 490. In any case, it can be seen that the starting material 433A, the film, is overall homogeneous over its entire surface area, i.e. that the corresponding Velcro projections 434 are evenly distributed over the entire surface. The extrusion Velcro 434 is attached, for example, to a cushion 430 by means of an adhesion promoter film 429 or is glued on directly. It is also possible for the cushion 430 to be foamed directly onto the extrusion film 434 or the adhesion promoter film 429, for example in the context of a foaming process FOA. In any case, a homogeneous product that deforms evenly when loaded by the contact pressure P or a correspondingly evenly deformed grinding plate 412 is obtained in this way, in such a way that especially in the edge area of the grinding plate 412, where the abrasive machining under load from the contact pressure P in Essentially takes place, a processing surface that rests uniformly on the workpiece surface of the workpiece V is created or is formed.

The example of the cushion 430 should make it clear that, for example, a deformation contour 431 can also ensure that the cushion 430 moves when the contact pressure P is applied (corresponding to the direction of the arrow FOA in FIG Figure 12 ) is flat against the workpiece surface of workpiece V. For example, the deformation contour 431 comprises a notch 431. This notch 431 expediently runs radially in the direction of the central axis M. Holding means can be provided, for example on holding means 333 of grinding plate 310.

Claims (15)

1. Grinding disc for a grinding machine (90), wherein the grinding disc has a machine side (11) assigned to the grinding machine (90) and a machining face (12, 112, 212) assigned to the machining of a workpiece (V), wherein there are provided on the machine side (11) a tool holder mounting (15) for attaching to a tool holder (92) of the grinding machine (90), and on the machining face (12, 112, 212) an abrasive means (50) for machining a workpiece (V) or holding means (33) for releasable holding of such abrasive means (50), and wherein the machining face (12, 112, 212) of the grinding disc has an annular edge zone (44, 144, 214) for forming a flat support surface of the abrasive means (50) on the workpiece (V) and a central zone (45, 145, 245) surrounded by the annular edge zone (44, 144, 214), wherein the annular edge zone (44, 144, 214) extends from the central zone (45, 145, 245) towards the workpiece (V) and/or wherein the grinding disc has a lower compressive modulus in the central zone (45, 145, 245) than in the edge zone (44, 144, 214) so that, with a contact pressure (P) acting on the tool holder mounting (15) in the direction of the machining face (12, 112, 212), substantially the edge zone (44, 144, 214) is loaded towards the workpiece (V) for abrasive machining of the workpiece (V) or is in contact with the workpiece (V), characterised in that the abrasive means (50) for machining the workpiece (V) or the holding means (33) for releasable holding of such abrasive means (50) extend substantially over the whole machining face (12, 112, 212) including its centre.
2. Grinding disc according to claim 1, characterised in that the machining face (12, 112, 212) has a step and/or an inclined surface between the edge zone (44, 144, 214) and the central zone (45, 145, 245), so that in the central zone (45, 145, 245) a recess (46, 246) is formed and/or the machining face (12, 112, 212) has a trough in the central zone (45, 145, 245).
3. Grinding disc according to claim 1 or 2, characterised in that the central zone (45, 145, 245) has on the radial outside an inclined surface and/or a step to the edge zone (44, 144, 214), wherein the inclined surface or step is provided between the edge zone (44, 144, 214) and a substantially flat inner part of the central zone (45, 145, 245).
4. Grinding disc according to any of the preceding claims, characterised in that it has a support plate (13, 113, 213) with the machine side (11) and on which is provided a flexible cushion (30, 130, 230) which has the machining face (12, 112, 212) on its side facing away from the support plate (13, 113, 213).
5. Grinding disc according to the claim 4, characterised in that a holding area (28) of the support plate (13, 113, 213) facing the machining face (12, 112, 212) and provided for holding the cushion (30, 130, 230) has a support edge zone (24) assigned to the edge zone (44, 144, 214) of the machining face (12, 112, 212) and a support central zone (25) assigned to the central zone (45, 145, 245) of the machining face (12, 112, 212),wherein the support edge zone (24) protrudes further in the direction of the machining face (12, 112, 212) than the support central zone (25) or is more rigid than the support central zone (25), wherein it is advantageously provided that an inclined surface (26), in particular conical, and/or a step are or is located between the support central zone (25) and the support edge zone (24).
6. Grinding disc according to any of claims 4 or 5, characterised in that a material thickness of the cushion (30, 130, 230) and/or of the support plate (13, 113, 213) in the edge zone (44, 144, 214) and in the central zone (45, 145, 245) are substantially identical or identical over the projected area of the machining face (12, 112, 212) and/or that a distance, between an underside of the cushion (30, 130, 230) and/or the support plate (13, 113, 213) facing the machining face (12, 112, 212) and the machining face (12, 112, 212), is substantially identical or identical in the edge zone (44, 144, 214) and the central zone (45, 145, 245), and/or that the cushion (30, 130, 230) on its underside facing the machining face (12, 112, 212) or the underside forming the machining face (12, 112, 212) protrudes closer to the machining face (12, 112, 212) in the edge zone (44, 144, 214) than in the central zone (45, 145, 245), in particular having a step and/or an inclined surface between the central zone (45, 145, 245) and the edge zone (44, 144, 214).
7. Grinding disc according to any of the preceding claims, characterised in that there is in the central zone (45, 145, 245) at least one airflow passage (71) for a fresh air flow or a dust-laden airflow, wherein the airflow passage or passages (71) extends or extend between the machining face (12, 112, 212) and the machine side (11), wherein the airflow passage or passages (71) expediently form part of an arrangement (70), in particular annular, of airflow passages (71).
8. Grinding disc according to any of the preceding claims, characterised in that a surface area of the edge zone (44, 144, 214) is greater, in particular approx. 1.5-2 times greater, preferably two to three times greater, than a surface area of the central zone (45, 145, 245), and/or that the holding means (33) for the abrasive means (50) comprise a Velcro mounting (34), and/or that an outer peripheral section (42) of the edge zone (44, 144, 214) facing away from the central zone (45, 145, 245) is curved away from the surface of the workpiece (V) to be machined or has a step.
9. Grinding disc according to any of the preceding claims, characterised in that the abrasive means (50) have a sheet-like or disc-like shape and/or are matched to a contour of the machining face (12, 112, 212) when mounted on the grinding disc, in particular having a recess or trough in the central zone (45, 145, 245), and/or that the abrasive means (50) span a portion of the central zone (45, 145, 245) with clearance from the machining face.
10. Grinding disc according to any of the preceding claims, characterised in that the machining face (12, 112, 212) and/or the abrasive means (50) and/or the holding means (33) have or has airflow passages (71, 54), in particular arranged in the central zone, for the supply of fresh air and/or removal of waste air, in particular dust-laden.
11. Grinding disc according to claim 10, characterised in that the machining face (12, 112, 212) and/or the abrasive means (50) and/or the holding means (33) have no interruptions apart from the airflow passages (71, 54) and/or are designed and/or provided for flat contact with the workpiece (V).
12. Grinding disc according to any of the preceding claims, characterised in that there are provided, on the machining face (12, 112, 212) and/or the abrasive means (50) and/or the holding means (33), slits (363) and/or interruptions and/or deformation contours (431) which facilitate or make possible a flat position of the machining face (12, 112, 212), in particular the edge zone (44, 144, 214), on the workpiece (V) during deformation of the machining face (12, 112, 212) from a state in which it is not loaded by the contact pressure (P) into a state in which it is loaded by the contact pressure (P), wherein advantageously it is provided that the slits (363) and/or interruptions (364) and/or deformation contours (431) run radially or in a star-shaped pattern relative to a centre axis (M) of the grinding disc (10, 110, 210), and/or that the slits (363) and/or interruptions (364) and/or deformation contours (431) are provided only or also in the annular edge zone (44, 144, 214).
13. Grinding disc according to any of the preceding claims, characterised in that the holding means (33) include a film or extruded burr (434) or are formed thereby and/or contain no fibres, wherein it is provided advantageously that the film comprises an extruded film or adhesive film and/or that the film or extruded burr (434) is bonded with the aid of a bonding agent film (429) to a flexible cushion (430) of the grinding disc (410) and/or that the flexible cushion (430) is applied to the film or extruded burr (434) by foaming-on.
14. Grinding disc according to any of the preceding claims, characterised in that no component or only a soft component of the grinding disc's support plate (13, 113, 213) contains fibres (361, 362) or fibres running transversely, in particular parallel, to the machining face (12, 112, 212), and/or that the machining face (12, 112, 212) and/or the abrasive means (50) and/or the holding means (33) are or is divided into circular segments or angular segments.
15. Hand-guided grinding machine (90) with a drive unit (93A), having a drive motor (93) and in particular a gearbox (95), for driving a tool holder (92) for holding a grinding disc and with a grinding disc (10, 110, 210) according to one of the preceding claims, wherein the drive unit (93A) is designed for rotary and/or eccentric and/or hypercycloid driving of the tool holder (92), wherein it is advantageously provided for the grinding machine (90) that it has a handle (96), in particular bar-like, which is firmly fixed or movably hinged to a casing of the grinding machine (90) for force transmission in the area of the tool holder (92), and/or that it has a dust removal device (94A), wherein a suction opening (94C) or the suction opening (94C) of the dust removal device (94A) is arranged advantageously eccentric to a centre axis (M) of the grinding disc (10, 110, 210), and airflow passages (71, 54) of the grinding disc (10, 110, 210) and/or of the abrasive means (50) which communicate with the machining face (12, 112, 212) and the suction opening (94C) are arranged in an annular pattern around the centre axis (M).

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