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(11) | EP 0 839 608 B1 |
| (12) | EUROPEAN PATENT SPECIFICATION |
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| (54) |
A polishing and smoothing machine for slabs, tiles and the like. Polier- und Glättmaschine für Platten, Kacheln und dergleichen Machine pour aplanir et polir des dalles, du carrelage ou similaire |
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| Note: Within nine months from the publication of the mention of the grant of the European patent, any person may give notice to the European Patent Office of opposition to the European patent granted. Notice of opposition shall be filed in a written reasoned statement. It shall not be deemed to have been filed until the opposition fee has been paid. (Art. 99(1) European Patent Convention). |
[0002] In particular, but not exclusively, the invention is applicable in the smoothing of marble slabs and ceramic tiles made of the material known as porcelain stoneware.
[0003] WO-A-95/30515 discloses the nearest prior art and particularly describes a polishing-smoothing machine for slabs, tiles and the like, comprising
a mobile rest plane for the slabs or tiles, whereon the slabs or tiles are conveyed in a predetermined direction;
a rotating plafform, commanded to rotate about an incident axis on said mobile rest plane and provided with at least one frontal rotating grinding wheel which rotates about an axis not coinciding with the rotation axis of the platform and which is predisposed to operate in contact with at least one slab or tile situated on said plane;
said rotation axis of said at least one frontal rotating brinding wheel being inclined, having a inclination which is predetermined with respect to a perpendicular of said mobile rest plane.
[0004] The prior art teaches polishing marble slabs and porcelain stoneware tiles using sanding machines having a plurality of grinders arranged in line which operate on the slab or tile first by smoothing the work-surface and then, with a series of passages under progressively-finer grinders, by progressively polishing same. A characteristic of this working technique is the removal of a considerable breadth of material from the face of the slab or tile, i.e. a breadth which is sufficient to produce a perfectly flat surface which is necessary in order to obtain a fine shine.
[0005] For porcelain stoneware tiles, in particular, this type of sanding has the drawback of opening up microporosities (which are not present in the piece as it exits from the kiln) which causes the polished surface to stain when in contact with dirt particles small enough to lodge in these porosities. Consequently it is usually necessary to apply a further proofing process, whereby the tiles are treated with a substance able to impregnate the microporosities and render them safe from dirt infiltration.
[0006] A further serious limitation of the prior art relating to sanding is that it is not at all able to produce a smooth finish or polish on irregular, i.e. not perfectly flat surfaces. This in effect means that the kinds of tile known as structured, which are designed to have irregular rough surfaces (the prior art, indeed, presupposes that all surface irregularities have to be levelled before polishing can take place) cannot be polished.
[0007] The present invention, as it is characterised in the claims that follow, provides a polishing and smoothing machine able to carry out a surface treatment which makes the tile or slab surface shinier and smoother without detracting from the original geometric conformation thereof.
[0008] A further aim of the present invention is to perform a smoothing operation which is characterised by the removal of a very small breadth of material.
[0009] A still further aim of the present invention is to realise various degrees of finish without leaving any sign of working whatsoever on the worked surface.
[0010] An advantage of the present invention consists in its constructional, functional and operative simplicity.
[0011] A further advantage of the present invention is its ability to work with consistent results on products having flat and regular surfaces but also on those having irregular surfaces and conformations.
[0012] A still further advantage of the present invention consists in the fact that it can be used for obtaining special products, such as antiquated marbles.
[0014] Further characteristics and advantages of the present invention will better emerge from the detailed description that follows of some preferred but non-exclusive embodiments of the invention, illustrated purely by way of nonlimiting examples in the accompanying figures of the drawings, in which:
figure 1 is a schematic vertical-elevation frontal view of a first embodiment of the invention;
figure 2 is a schematic lateral view from the left of figure 1;
figure 3 is a schematic view from above of figure 1 with some parts removed better to evidence others;
figure 4 is a schematic frontal view of a second embodiment of the invention. With reference to the figures, 1 denotes in its entirety a mobile rest plane for slabs or ceramic tiles 2 along which the tiles are translated in the direction indicated by the arrow 5. The plane 1 is constituted, for example, by the upper branches 10 of a normal pair of conveyor belts for ceramic tiles supported during motion by guides 11, horizontal guides in the present example. In the first embodiment shown, a rotating platform 3 is arranged above the plane 1. The platform 3 rotates about an axis x-x which is perpendicular to the plane 1 and arranged on the same longitudinal halfway-line. The platform 3 is mounted on a motor head 6 which in turn is vertically-slidably coupled on a vertical guide 7 fixed to a frame. A known-type device, not illustrated in the figures, presses the motor head 6 downwards against the tiles on the plane; the entity of the downwards pressure being adjustable and predetermined.
[0015] The rotating platform 3, in the embodiment shown in figures 1 and 2, inferiorly bears a plurality of rotating frontal brushes 4 which are arranged in such a way as to form a crown about axis x-x of the platform itself.
[0016] With reference to the presence of a plurality of frontal rotating brushes supported on the rotating platform, it should be noted that the essential characteristics and specific functionality of the invention are all perfectly expressed in an embodiment having at least one frontal rotating brush, obviously having all of the attributes of each of the frontal rotating brushes of said plurality of brushes.
[0017] The frontal rotating brushes 4 are mounted idle on the platform 3, that is, with full rotating liberty about respective axes thereof, which axes are inclined at a predetermined angle with respect to a perpendicular of the plane 1. In particular, the rotation axis of each brush 4 is contained within a plane which also contains the rotation axis x-x of the platform 3. The angle at which the rotation axis of each brush 4 is inclined with respect to the perpendicular of the plane 1 is small - preferably about 1 sexagesimal degree.
[0018] The rotation axes of the brushes 4 are arranged in such a way that the active frontal surfaces of the brushes are turned towards the rotation axis x-x of the platform.
[0019] Each brush 4 is constituted by a disc 40. Bristles 41 are arranged in a circular crown on the downwards-turned face of the disc 40, which bristles can be made of any of various materials. In the present example, concerned with porcelain stoneware, they are made of a composite, the preference being for a plastic material functioning as a bond comprising abrasive particles of a predetermined granulometry.
[0020] During normal functioning the slabs or tiles 2 are translated on the plane 1 in the direction indicated by the arrow 5. Two lateral containment edges 9, situated in the operative zone of the brushes 4, prevent lateral displacements of the tiles 2 during the smoothing operation.
[0021] The brushes 4 contact the upper surface of the slab or tile 2 with a predetermined pressure obtained with said known device (not illustrated) having the task of keeping the whole motor head 6 pressed downwards (i.e. against the surface of the slab or tile 2) at a predetermined and adjustable pressure.
[0022] Each brush 4 comes into contact with the upper surface of the slab or tile 2 only at one zone of the brush 4 frontal surface, due to the fact that the brush 4 rotation axis is slightly inclined with respect to the perpendicular of the upper surface of the slab or tile 2. This geometric situation, combining with the rotation about its own axis x-x of the platform 3, generates a tangential force on the brush, causing it to rotate. Thus, when the brushes 4 are in contact with the slab or tile 2 they are automatically drawn into rotation about their respective axes.
[0023] As a result of the combination of movements generated, the ends of the bristles 41 come into contact with the upper surface of the slab or tile 2, dragging thereupon over short tracts thereof, during which, thanks to the abrasives contained in the bristles themselves, a mechanical smoothing action is produced, characterised by the removal of very small quantities of material.
[0024] Overall, when working on homogeneous materials, the original profile of the workpiece surface is not changed (in this case, the workpiece surface being the whole upper surface of the slab or tile 2); the operation is limited to smoothing the surface.
[0025] For the above reason, the device is particularly useful in smoothing-polishing operations on irregular and not perfectly flat surfaces, such as those of tiles made of porcelain stoneware, known as "structured" .
[0026] A further fundamental characteristic of the invention is that it polishes and smooths without leaving any marks, such as scoring, on the workpiece surface, independently of the degree of finishing required. This degree of finishing essentially depends on the granulometry of the abrasive contained in the bristles forming the single brushes.
[0027] In order to obtain a predetermined degree of slab or tile surface finish, the work surfaces are passed through a series of machine operations, rather like the one described above. The machines are arranged in line, and each is equipped with brushes 4 having bristles 41 impregnated with abrasives of varying granulometry. The work order is organised so that a gradually decreasing abrasive granulometry (as well as different kinds of abrasives) comes into contact with the work surface.
[0028] A further embodiment of the invention uses a platform 3' arranged with its rotation axis x'-x' inclined with respect to the vertical of the plane 1'. In this case, too, the inclination is of small entity, preferably about 1 degree.
[0029] The platform 3' bears a plurality of brushes 4', structurally identical to the brushes 4 of the first embodiment, but having rotation axes parallel to the rotation axis x'-x' of the platform 3'. Thus the axes thereof are also inclined with respect to the perpendicular of the plane 1'. This geometrical situation is the cause of the rotation of the brushes 4', which are in contact with the underlying slab or tile 2, due to the effect of the rotation of the platform 3'. The overall result is similar to that obtained in the first embodiment.
a mobile rest plane (1) for the slabs or tiles (2), whereon the slabs or tiles (2) are conveyed in a predetermined direction;
a rotating platform (3, 3'), commanded to rotate about an incident axis on said mobile rest plane (1) and provided with at least one frontal rotating brush (4, 4') which rotates about an axis not coinciding with the rotation axis of the platform (3, 3') and which is predisposed to operate in contact with at least one slab or tile (2) situated on said plane (1);
said rotation axis of said at least one frontal rotating brush (4, 4') being inclined, having a inclination which is predetermined with respect to a perpendicular of said mobile rest plane (1).
characterised in that the rotation axis of said rotating platform (3') is inclined, with a small entity of inclination, with respect to the perpendicular of said mobile rest plane (1); the rotation axis of said at least one frontal rotating brush (4') being parallel to the rotation axis of the platform (3').
eine bewegliche Auflagefläche (1) für die Platten oder Kacheln (2), auf welcher die Platten oder Kacheln (2) in einer bestimmten Richtung weitergeleitet werden;
eine drehbare Plattform (3, 3'), die angetrieben wird, sich um eine auf die bewegliche Auflagefläche (1) auftreffende Achse zu drehen und mit wenigstens einer frontalen, drehbaren Bürste (4, 4') versehen ist, welche sich um eine nicht mit der Drehachse der Plattform (3, 3') übereinstimmende Achse dreht und dazu vorgesehen ist, im Kontakt mit wenigstens einer der auf der genannten Fläche (1) liegenden Platten oder Kacheln (2) zu arbeiten;
wobei die genannte Drehachse der genannten wenigstens einen frontalen, drehbaren Bürste (4, 4') geneigt ist, wobei sie eine Neigung hat, die im Verhältnis zu der Lotrechten der genannten beweglichen Auflagefläche (1) festgelegt ist.
un plan d'appui mobile (1) pour les dalles ou carrelage (2), sur lequel les dalles ou carrelage (2) sont convoyés dans une direction prédéterminée;
une plateforme rotative (3, 3'), commandée pour pivoter autour d'un axe incident audit plan d'appui mobile (1) et pourvue d'au moins une brosse frontale rotative (4, 4') qui pivote autour d'un axe ne coincidant pas avec l'axe de rotation de la plateforme (3, 3') et qui est prédisposée pour opérer en contact avec au moins une dalle ou carrelage (2) situé sur ledit plan (1);
ledit axe de rotation de ladite brosse frontale rotative (4, 4') étant incliné, ayant une inclinaison prédéterminée par rapport à une perpendiculaire audit plan d'appui mobile (1).