EP1879728B1

EP1879728B1 - A process for die filling supply, in forming of tiles or like products

Info

Publication number: EP1879728B1
Application number: EP06727520A
Authority: EP
Inventors: Umberto Giovanardi
Original assignee: R P Srl
Current assignee: R P Srl
Priority date: 2005-04-29
Filing date: 2006-03-28
Publication date: 2012-12-19
Anticipated expiration: 2026-03-28
Also published as: EP1879728A1; ES2401698T3; PL1879728T3; PT1879728E; ITMO20050106A1; WO2006117606A1

Description

Technical Field

The invention relates to a supply and discharging process for the dies, in the production process of forming ceramic tiles and like products according to the pre-amble of claim.

Background Art

In the prior art, in production processes for ceramic tiles or cement or resin blocks, the formation stage is performed by using special presses, having one or more dies, to which are associated devices and means for loading the forming cells of the dies with the powder material destined for the composition of the various products.
The means and devices comprise trays or trucks, consisting of rectangular frames that are translatable horizontally on a plane interpositioned between the bottom die and the top die of the press, from a first position, external of the press, in which the tray is filled with the powder material to be pressed, to a second position, exactly above the die cell, in which the powder is transposed by force of gravity into the cell from the tray or truck.
The means and devices further comprise double-loading devices, which work in conjunction with the trays described above, positioned on the opposite side of the press, to discharge a second layer of material into the cell, which second layer is of a different thickness and composition from the preceding layer, and is destined, for example, to constitute the decoration of the tiles. These devices are constituted by belt conveyors, which are sufficiently long to guarantee the depositing on the upper surface thereof of successive layers arranged at a predetermined distance and being of a number which is sufficient to sustain the pressing speed the forming press can operate at; the belt conveyors are also provided with a terminal portion which is horizontally translatable up until reaching the position of the die cell, after which it retreats at a speed and timing which is such as to permit the transfer of the layers into the die cell, with as little loss of powders and damage to the layer shape as possible.
EP-A1-175985 discloses a process for die filling in process according to the pre-amble of claim 1.
The main aim of the present invention is to provide a process for supplying press dies and for unloading the formed products, which process can be actuated flexibly and reliably using simplified means and devices.
The above-mentioned aim and others besides are all attained by a process of supplying the dies, in the process of the invention, includes stages of:

depositing layers of power materials on the upper surface of belt conveyors;
advancing a terminal portion of the conveyors into the zone comprised between the bottom die and the top die, above the cells of the dies;
retracting the terminal portion, with a contemporary evacuation of the layer or layers of material lying on the belt, into the underlying cell or cells; and repeating the advancing and retracting stages of the terminal portions of the conveyor belts for each of the additional layers of material to be deposited in the cells, forming a single product.

The process advantageously includes, during the stage of advancing the terminal portion of the conveyors into the zone comprised between the bottom and top dies, the expulsion of the products formed in the previous forming cycle; further, during the stage of retraction of the terminal portion, the material released by the belt into the die cell is skimmed.
The advantages of the present invention over processes of the prior art for filling die cells in forming of ceramic tiles and the like is obvious from the above summary, especially in terms of the simplification of the machines and equipment associated to the forming presses, as well as in relation to the flexibility and reliability of the cell-loading process which is described above.

Disclosure of Invention

Further advantages of the present invention will better emerge from the detailed description that follows of a preferred but not exclusive embodiment of the invention, illustrated purely by way of non-limiting example in the accompanying figures of the drawings, in which:

Figure 1 is a schematic view in longitudinal section of a die filling apparatus according to the invention;
Figure 2 is a detail seen from above of the apparatus of figure 1;
Figures 3 and 4 are a longitudinal section and a view from above of a terminal part of the apparatus of figure 1, in an operative configuration;
Figure 5 and 6 are a longitudinal section view and a view from above of the same terminal part of the apparatus of figures 3 and 4, but in a different operative configuration;
Figure 7 is a detailed view relating to the configuration of figure 5;
Figures 8 and 9 show two further detailed views in reference to two possible work modes of the apparatus of the invention;
Figures 10 and 11 show a view in longitudinal section and a view from above of the apparatus, similar to the view illustrated in figures 1 and 2, but relating to a different work mode of the invention.

With reference to figure 1, 10 denotes in its entirety an apparatus for supplying dies of pressing machines 11 used in the present description during the process of forming ceramic tiles before the stage of firing the tiles.
The apparatus 10 comprises a conveyor belt 12, associated to devices 13 arranged above the belt 12, at prefixed distances in order to deposit thereon layers 14 of powder material destined to make up the tiles.
In particular, the terminal portion 15 of the conveyor belt 12 is horizontally translatable, with the help of suitable means 16 of known type and, for example, described in European patent 1, 175, 985 granted to the same applicant, towards the zone interpositioned between the top die 10 and the bottom die 19, comprising the cell 20, in which the powder material transported by the conveyor belt 12 is deposited by the belt 12 itself.
A bar 21 is connected to the terminal portion 15 of the conveyor belt 12; the bar 21 is arranged at a fixed distance, in front of the front edge 22 of the belt 12, by means of connection and support arms 23, constrained at the two sides of the belt 12. The bar 21 comprises, in this embodiment, as we can see in the detailed view of figure 7, a first part 24, arranged in an advanced position and destined to push the tiles 27, after forming thereof, from the press 11 towards a conveyor 30 arranged in an opposite position to the conveyor belt 12, and a second part 25, arranged in a more internal position and destined to skim the layer of powders deposited by the belt 12 in the cell 20, the second part 25 of the bar 21 being inferiorly provided with a doctor 26 for skimming.
The process of supply to the dies and unloading the formed products of the above-described apparatus can be illustrated, in particular, with reference to figures from 3 to 6.
Figure 3 illustrates a stage in which the layers 14 of powder material, previously deposited on the conveyor belt 12 by special means for loading 13, are brought into the zone comprised between the top die 18 and the bottom 19, thanks to the advancement of the terminal portion 15 of the conveyor belt 12. Thanks to the advancement motion of the terminal portion 15, during this stage there is also an expulsion from the press 11 of the tiles 27 formed during the previous pressing cycle, the tiles being brought into the position for expulsion by a lifting run of the bottom die 19.
As soon as the bottom die 19 is brought back into the normal work position illustrated in figure 5, the retraction run of the terminal portion 15 of the conveyor belt 12 is started, by returning the lower part of the belt 12 by means of special means for returning 16 schematically illustrated in figure 1. During the return run, in this embodiment, there is transfer by force of gravity of the layers of powder material 14 from the belt 12 into the cells 20, as well as the top-layer skimming of the powders when deposited in the cells 20, the skimming being performed thanks in particular to the translating motion of the internal part 25 of the bar 21 drawn solidly with the terminal portion 15 of the conveyor belt 12; this is all clearly illustrated in figure 7.
Figure 5 relates to a case in which the tiles being formed are made up of a single layer of powder material. Therefore, once the terminal portion 15 of the conveyor belt 12 has completed its return run, up to the position illustrated in figure 1, there is a pressing operation on the powders in the cell 20, via the top die 18, after which the bottom die 19 is raised by an amount which brings the formed tile 27 up to the height of the expulsion bar 21.
Figures 8 and 9 show a detail of figure 7, which relates to a case in which a further embodiment of the process is actuated, which further embodiment leads to the formation of tiles made up of several layers of different materials. In more detail, in the illustrated embodiment the tiles have three layers, 31, 32 and 33, of powder materials destined respectively to make up the main body layer of tile, a zone having a different density, being the base layer, and an upper or surface layer, also known as the decor layer, which comprises decorations, glazing or the like. The above-mentioned layers can be arranged in either order, top to bottom, as shown in figure 8, or bottom to top, as shown in figure 9, and they can obviously be interpositioned with respect to other layers of material having specific compositions and functions, according to the various required applications, the supply process to the dies being in all cases the same, see figures 10 and 11.
The view from above of figure 11 shows that the various layers of materials 31, 32 and 33 are successively laid on the conveyor belt 12, by means of the loading devices 13 controlled in synchrony with the advancing of the conveyor belt 12. As the layers reach the terminal portion 15 of the conveyor belt 12, between a pressing run and a next pressing run, there is an advancing and retracting motion of the terminal portion for each pair of layers, so that they are deposited into a pair of cells in the same order in which the layers are arranged on the conveyor belt 12. Obviously the expulsion of the formed tiles 27 occurs only at the first of the above-mentioned series of advancing and retraction movements of the terminal portion 15 of the conveyor belt 12, while the skimming of the deposited powders is done at the same time as the last retracting motion of the above-mentioned series of movements, comprised between one pressing run and the next.
Thanks to the above-described apparatus and process the forming process of ceramic tiles or cement or resin blocks or the like, simplified pressing machines are made available, while at the same time a wide-ranging flexibility of production is possible. These advantages are maintained even where variants or further embodiments of the above-described machine are used.
For example, the length and conformation of the conveyor belt 12 might vary according to the type of products to be made, and consequently the number and arrangement of the devices 13 for depositing the various layers of materials on the belt might also change. The conformation of the expulsion bar for the formed products might also be changed; the integration of the use thereof with the skimming function might be changed.
Further, in performing the forming process of the apparatus of the invention, the stage of skimming the material might not be included, such as for example in the case of forming tiles superiorly exhibiting a decoration layer, where the overall height of the tiles is lower than the height/depth of the cell. Other modifications might involve the means for advancing and retracting the terminal portion of the conveyor belt; or the means for receiving the formed products when they are expelled from the pressing machine.

Claims

A process for die filling in presses, in the process of forming multilayer tiles or like products, wherein the process for die filling comprises:
depositing powder materials layers (14;31,32,33) on an upper surface of

conveyor belts (12);

advancing a terminal portion (15) of the conveyor belts (12) in a zone comprised between a bottom die (19) and a top die (18), above cells (20)

of the dies of the presses (11);

retracting the terminal portion (15) with a contemporaneous release of a

layer (31) or layers (31) of material supported into the underlying cell (20) or cells: characterized by

repeating the stages of advancement and retraction of the terminal portion (15) of the conveyor belts (12) for each layer (32;33) of the various layers of material, to be deposited in the cells (20), forming a single product (27).
The process of claim 1, wherein during the stage of advancing the terminal portion (15) of the conveyor belts (12) into the zone comprised between the bottom die (19) and the top die (18), there is also an expulsion of products (27) formed during a previous pressing cycle.
The process of claim 1 or 2, wherein it comprises a skimming operation of material released from the conveyor belts (12) into the cell (20) or cells, the operation taking place during a retraction stage of the terminal portion (15) of the conveyor belts (12).