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EP 1 136 211 B1 |
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EUROPEAN PATENT SPECIFICATION |
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Mention of the grant of the patent: |
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02.06.2004 Bulletin 2004/23 |
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Date of filing: 23.03.2000 |
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A device for forming ceramic products, including slabs, tiles and the like, by powder
pressing
Vorrichtung zum Herstellen von keramischen Gegenständen wie zum Beispiel Platten ,
Fliesen und ähnlichen Artikeln durch Pressen von Pulver
Dispositif pour la fabrication d'articles en céramique comme par exemple des dalles,
des carreaux et des articles similaires par pressage de poudre
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Designated Contracting States: |
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DE ES GB IT PT |
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Date of publication of application: |
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26.09.2001 Bulletin 2001/39 |
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Proprietor: SYSTEM S.p.A. |
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41042 Fiorano Modenese (MO) (IT) |
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Inventor: |
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- Stefani, Franco
41049 Sassuolo (MO) (IT)
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Representative: Gotra, Stefano |
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BUGNION S.p.A.
Via Emilia Est 25 41100 Modena 41100 Modena (IT) |
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References cited: :
WO-A-98/23424 GB-A- 647 144 US-A- 5 779 957
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DE-A- 1 965 173 GB-A- 2 260 318
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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).
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[0001] The prior art in the field of forming ceramic tiles is based on the use of dies inserted
into presses. The dies are, schematically speaking, constituted by a cavity into which
powders are deposited, and by at least one punch having the task of pressing the deposited
powders. Such a device is known from GB-A-647 144.
[0002] Also known is the use of dies in which the cavity is not made in the bottom die;
this is instead used for depositing a layer of powders which is then pressed by the
top die or punch. Delimitation and lateral containment of the material to be pressed
to form the tile or slab is performed by a forming frame associated to the punch or
top die, which projects from the top die so that it can remain in contact with the
bottom plane (bearing the powders to be pressed) during the pressing operation.
[0003] This solution exhibits a number of constructional complexities due to the need to
predispose devices for vertically moving the frame with respect to the punch, and
is subject to problems of wear on the moving parts.
[0004] A further and not easy-to-solve drawback concerns the need to provide a device for
cleaning the punch between one pressing operation and a next.
[0005] The main aim of the present invention is to provide a device for forming ceramic
products, such as slabs, tiles and the like, by powder pressing, which will obviate
the above-described drawbacks and limitations inherent in the prior art.
[0006] The invention is constructionally simple and functional.
[0007] A further advantage of the invention is the fact that it enables a punch-cleaning
operation to be carried out between one pressing operation and a next both away from
the pressing zone and easily.
[0008] These aims and advantages and more besides are all attained by the object of the
invention, as it is characterised in the appended claims.
[0009] Further characteristics and advantages of the present invention will better emerge
from the detailed description that follows of a preferred but non-exclusive embodiment
of the invention, illustrated purely by way of a non-limiting example in the accompanying
figures of the drawings, in which:
figure 1 is a schematic longitudinal section made according to a vertical plane which
is parallel to the advancement direction of the materials being pressed;
figure 2 is an enlarged-scale drawing of a detail of figure 1;
figure 3 is the same detail as in figure 2, in a different operative configuration.
With reference to the above-mentioned figures, 1 denotes in its entirety a device
for forming ceramic products, such as slabs and tiles and the like, by powder pressing,
which is schematically constituted by a press 11 with a central aperture crossed through
by a lower element 2, constituted by a lower continuous belt 12 exhibiting a rest
plane 3 to support the powder 20 to be pressed, and an upper element 4, constituted
by the horizontal branch of an upper continuous belt 15, ring-wound and stretched
between two drums 16 having parallel axes and being positioned externally, which upper
continuous belt 15 constituting the upper element 4 is driven in synchrony with the
lower continuous belt 12 constituting the lower element 2.
[0010] The lower element 2 lies and slides along an upper surface of the piston 10 of the
press 11 and is commanded by the piston 10 to displace upwards in order to exert the
pressing action.
[0011] The upper element 4 is provided with a plurality of active surfaces 5, located and
distributed in a predetermined order along the upper continuous belt 15. At each pressing
event the active surfaces 5 are brought into contact with the rest plane 3 of the
lower continuous belt 12.
[0012] Each active surface 5 is characterised in that it is provided with a forming frame
6 which projects inferiorly (when the active surface 5 is in contact with the rest
plane 3) and is predisposed in such a way as to delimit at its perimeter a closed
pressing zone.
[0013] A plurality of forming frames 6 can be predisposed on the upper continuous belt 15,
each different from another, so that the type of surface to be obtained on the pressed
product can be alternated.
[0014] The forming frame 6 exhibits an internal part 7 which carries out the pressing of
the edge 22 of the final pressed product 21. This internal part 7 is externally delimited
by an edge 8 having a depth, measuring in the pressing direction, which is greater
than or equal to that of the central body of the final pressed product 21.
[0015] In particular, the internal part 7 inferiorly projects with respect to the active
surface 5 and presents a depth which gradually decreases as it distances from the
edge 8.
[0016] The whole forming frame 6 is constituted by a material provided with a consistent
elastic deformability (rubber or another elastomer).
[0017] The upper branch of the lower continuous belt 12 is moved in concordance with the
lower branch of the upper continuous belt 15.
[0018] In the described structure, the lower rest plane 3 also functions as the bottom die
of the forming device.
[0019] During the pressing phase, the piston 10 rises, raising the part of the lower element
2 on which the powder to be pressed has been deposited, thus pressing the powder against
the active surface 5 delimited by the forming frame 6 of the upper continuous belt
15.
[0020] While the edges 8 have mainly the task of perimetrally defining the area of compression,
the internal parts 7 have the function of realising, at the edge of the powder, a
perimeter area of greater compression with respect to the central part of the powders,
thus creating a more compacted zone at the edge of the pressed slab or tile.
[0021] The presence of this more compressed zone, which is removed by a cut after firing,
and especially in the case of slim slabs or tiles, has essentially the very important
task of preventing formation of fissures or cracks in the body of the slabs or tiles
themselves.
[0022] An advantage of the present invention is that the slab- or tile-forming operation
is rendered very simple and rapid, especially when the slabs or tiles are of large
dimensions but are relatively slim.
1. A device for forming ceramic products, including slabs, tiles and the like, by powder
pressing, comprising:
a lower element (2) bearing a lower rest plane (3) for supporting a powder to be pressed
(20), the lower rest plane (3) also functioning as a bottom die of the device;
an upper element (4) having at least one active surface (5), predisposed facing the
lower rest plane (3), the at least one active surface (5) being provided with a forming
frame (6) which projects inferiorly and which is predisposed in such a way as to delimit
a perimeter of a closed pressing zone; characterised in that
the forming frame (6), as well as delimiting a perimeter of a closed pressing zone
and therefore also delimiting a corresponding final pressed product (21), having such
a shape as to generate an edge (22) of the final pressed product (21) which has a
greater density than the density of internal zones of the final pressed product (21);
the edge (22) having the task of preventing formation of fissures or cracks in the
body of ceramic products, slabs, tiles and the like, themselves.
2. The device of claim 1, characterised in that the forming frame (6) exhibits an internal part (7) which presses the edge (22) of
the final pressed product (21) and which is delimited externally by a delimiting edge
(8) having a depth which, measured in a pressing direction, is greater than or equal
to a depth of the final pressed product (21).
3. The device of claim 2, characterised in that the internal part (7) projects inferiorly with respect to the active surface (5)
and gradually decreases in depth in a direction going from the delimiting edge (8)
towards the active surface.
4. The device of claim 3, characterised in that the upper element (4) has at least one active surface (5) delimited by the forming
frame (6) is constituted by a lower branch of an upper continuous belt (15) which
is ring-wound and stretched between two drums (16) having parallel axes and being
externally positioned.
5. The device of claim 4, characterised in that at least the forming frame (6) is constituted by a material having considerable elastic
deformability properties.
6. The device of claim 5, characterised in that the ring-wound upper continuous belt (15) bears a plurality of active surfaces (5)
delimited by an equal plurality of forming frames (6), distributed along the upper
continuous belt (15).
7. The device of claim 6, characterised in that the lower element (2) bearing the lower rest plane (3) for supporting the powder
to be pressed (20) is constituted by an upper branch of the lower continuous belt
(12), which belt (20) moves in synchrony with the lower branch of the upper continuous
belt (15).
1. Vorrichtung zum Herstellen von keramischen Gegenständen wie zum Beispiel Platten,
Fliesen und ähnlichen Artikeln durch Pressen von Pulver, enthaltend ein unteres Element
(2), das eine untere Auflagefläche (3) zum Tragen eines zu pressenden Pulvers (20)
hält, wobei die untere Auflagefläche (3) auch als Bodenmatrize der Vorrichtung dient;
ein oberes Element (4) mit wenigstens einer aktiven Oberfläche (5), die der unteren
Auflagefläche (3) zugewandt angeordnet ist, wobei die wenigstens eine aktive Oberfläche
(5) mit einem Formrahmen (6) versehen ist, der nach unten hervorsteht, und der auf
solche Weise angeordnet ist, dass er den Umfang eines geschlossenen Pressbereiches
eingrenzt; dadurch gekennzeichnet, dass der Formrahmen (6), ausser dass er einen Umfang eines geschlossenen Pressbereiches
und somit auch ein entsprechendes fertig gepresstes Produkt (21) eingrenzt, eine solche
Form hat, dass eine Kante (22) des fertig gepressten Produktes (21) erzeugt wird,
welche eine grössere Dichte aufweist als die Dichte der internen Bereiche des fertig
gepressten Produktes (21); wobei die Kante (22) die Aufgabe hat, das Bilden von Rissen
oder Sprüngen in dem Körper der keramischen Produkte, Platten, Fliesen und ähnlichen
selbst zu verhindern.
2. Vorrichtung nach Patentanspruch 1, dadurch gekennzeichnet, dass der Formrahmen (6) einen internen Abschnitt (7) aufweist, welcher die Kante (22)
des fertig gepressten Produktes (2 1 ) presst, und welcher aussen von einem begrenzenden
Rand (8) von einer Tiefe umgeben ist, die in Pressrichtung gemessen grösser als oder
gleich ist wie eine Tiefe des fertig gepressten Produktes (21).
3. Vorrichtung nach Patentanspruch 2, dadurch gekennzeichnet, dass der interne Abschnitt (7) im Verhältnis zu der aktiven Oberfläche (5) nach unten
hervorsteht und in einer Richtung von dem begrenzenden Rand (8) zu der aktiven Oberfläche
hin allmählich in der Tiefe abnimmt.
4. Vorrichtung nach Patentanspruch 3, dadurch gekennzeichnet, dass das obere Element (4) wenigstens eine aktive Oberfläche (5) hat, eingegrenzt durch
den Formrahmen (6), und aus dem oberen Trum eines kontinuierlichen Bandes (15) gebildet
ist, welches ringförmig gewunden und zwischen zwei Trommeln (16) gespannt ist, die
parallele Achsen aufweisen und aussen angeordnet sind.
5. Vorrichtung nach Patentanspruch 4, dadurch gekennzeichnet, dass wenigstens der Formrahmen (6) aus einem Material hergestellt ist, das beachtliche
Eigenschaften der elastischen Verformbarkeit aufweist.
6. Vorrichtung nach Patentanspruch 5, dadurch gekennzeichnet, dass das ringförmig gewundene, obere kontinuierliche Band (15) eine Anzahl von aktiven
Oberflächen (5) aufweist, eingegrenzt durch eine gleiche Anzahl von Formrahmen (6),
die entlang dem oberen kontinuierlichen Band (15) verteilt sind.
7. Vorrichtung nach Patentanspruch 6, dadurch gekennzeichnet, dass das untere Element (2) zum Halten der unteren Auflagefläche (3) für das zu pressende
Pulver (20) durch einen oberen Trum des unteren kontinuierlichen Bandes (12) gebildet
ist, welches Band (12) sich synchron mit dem unteren Trum des oberen kontinuierlichen
Bandes (15) bewegt.
1. Dispositif pour la fabrication d'articles en céramique, tels que des dalles, carreaux
et articles similaires, par pressage de poudre, comprenant:
- un élément inférieur (2) supportant un plan d'appui inférieur (3) pour supporter
une poudre (20) à presser, le plan d'appui inférieur (3) fonctionnant également en
tant que demi-moule inférieur du dispositif;
- un élément supérieur (4) présentant au moins une surface active (5), prédisposée
pour faire face au plan d'appui inférieur (3), ladite surface active (5) étant pourvue
d'un cadre de formage (6) qui est saillant inférieurement e qui est prédisposé de
manière à délimiter un périmètre d'une zone de pressage fermée;
caractérisé en ce que le cadre de formage (6), tout en délimitant un périmètre d'une zone de pressage fermée
e donc délimitant également un correspondant produit fini pressé (21), présente une
forme telle qu'elle génère un bord (22) du produit fini pressé (21) ayant une densité
supérieure par rapport à celle des zones internes du produit fini pressé (21); le
bord (22) ayant la fonction de prévenir la formation de fissures ou fêlures dans le
corps des articles en céramique, dalles, carreaux e similaires.
2. Dispositif selon la revendication 1, caractérisé en ce que le cadre de formage (6) présente une partie interne (7) qui presse le bord (22) du
produit fini pressé (21) e qui est délimitée extérieurement par un bord délimitant
(8) présentant une profondeur qui, mesurée dans la direction de pressage, est supérieure
ou égale à une profondeur du produit fini pressé (21).
3. Dispositif selon la revendication 2, caractérisé en ce que la partie interne (7) est saillante inférieurement par rapport à la surface active
(5) et décroît graduellement en profondeur dans une direction partant du bord délimitant
(8) vers la surface active.
4. Dispositif selon la revendication 3, caractérisé en ce que l'élément supérieur (4) présente au moins une surface active (5), délimitée par le
cadre de formage (6), est constituée par une branche inférieure d'un tapis roulant
continu supérieur (15) enroulé autour et tendu entre deux tambours (16) ayant des
axes parallèles et étant extérieurement positionnés.
5. Dispositif selon la revendication 4, caractérisé en ce qu'au moins le cadre de formage (6) est constitué d'un matériau ayant de considérables
propriétés de déformabilité élastique.
6. Dispositif selon la revendication 5, caractérisé en ce que le tapis roulant continu (15) supporte une pluralité de surfaces actives (5) délimitées
par une même pluralité de cadres formants (6), distribués le long du tapis roulant
continu supérieur (15).
7. Dispositif selon la revendication 6, caractérisé en ce que l'élément inférieur (2) supportant le plan d'appui inférieur (3) pour supporter la
poudre (20) à presser est constitué d'une branche supérieure du tapis roulant continu
inférieur (12), lequel tapis roulant (20) se déplace en synchronisme avec la branche
inférieure du tapis continu supérieur (15).