ITRE20010114A1 - PROCESS AND PRESSING DEVICE FOR CERAMIC TILES - Google Patents

Description

DESCRIPTION

attached to a patent application for INDUSTRIAL INVENTION entitled: "Pressing procedure and device for ceramic tiles"

The present invention relates to a pressing process for ceramic tiles, as well as a device suitable for carrying out said process.

In the field of ceramic tiles, obtaining products that are both aesthetically valuable and having adequate technical performance has always been an extremely important goal.

With particular reference to ceramic tiles made of porcelain stoneware, whether they are polished or unpolished, glazed or unglazed, the search for increasingly refined and valuable aesthetic effects is combined with the excellent performance characteristics that this type of material is able to offer. Among the most advanced aesthetic effects, the so-called three-dimensional effects should certainly be mentioned, or generally those effects that recreate, on the visible surface of the tile, the aesthetic characteristics of natural stones, namely inclusions, veins, etc.

Currently, said aesthetic effects are recreated through a multiplicity of different techniques; generally, however, to obtain these precious effects on porcelain stoneware, it is preferable to intervene before or during the pressing phase of the ceramic tiles.

For example, solutions have been proposed which provide for varying, more or less randomly, the mixture of raw materials making up the tile mix, during the loading phase of the press feed carriage.

It is also possible to use feeding wagons equipped with suitably shaped grids, or even to use special coloring materials, optimized in order to obtain three-dimensional aesthetic effects. All these techniques, which can of course be used in combination with each other, although they guarantee the realization of fast and economical production cycles, are not however able to produce ceramic tiles with particularly sophisticated three-dimensional effects, such as the market today requires.

A more refined technique, on the other hand, involves the use of multiple pressing cycles, carried out within the same or multiple presses. In this way, at each subsequent pressing cycle, different quantities of precious material are added to the feeding carriage each time, in predetermined or even random proportions, to recreate, on the visible surface of the tile, a composite structure with several levels able to adequately simulate the three-dimensional effects of natural stone.

However, this solution has considerable drawbacks.

First of all, production cycles that implement this type of solution are extremely slow and costly to conduct.

Furthermore, this solution involves the use of so-called mirror molds, i.e. molds whose useful surface corresponds to the upper surface, i.e. visible, of the ceramic tile, which involves large wastes of valuable material at each subsequent shaving of the same, called shaving, i.e. the removal phase of the excess material from the feeding carriage, being necessary before each subsequent pressing phase.

Another solution consists in the use of a pre-compacted clayey semi-finished product thanks to an initial preliminary pressing phase, to be subsequently subjected to the addition of different quantities of valuable material in order to obtain the desired aesthetic effects.

After adding these precious materials, the actual pressing of the ceramic tile takes place.

This solution, compared to the previous one, has the advantage of allowing faster and cheaper production cycles to be obtained, at the expense, however, of an overall worsening of the technical and aesthetic characteristics of the finished product.

Furthermore, given the considerable fragility of the semi-finished products in question, the risk that one of these, breaking when it is placed on the mold of the press, and as a consequence of a pressing carried out in these conditions, causes damage to both the press that of the mold.

The present invention has the aim of solving the problems encountered in the known art.

In particular, the object of the present invention is to provide a pressing process for ceramic tiles, as well as a device suitable for carrying out said process, capable of obtaining high quality three-dimensional aesthetic effects, using simple equipment and carrying out cycles. fast and cheap production.

Another purpose of the present invention is to provide a pressing process for ceramic tiles, as well as a device suitable for carrying out said process, particularly suitable for obtaining three-dimensional aesthetic effects for porcelain stoneware ceramic tiles. A further object of the present invention is to provide a pressing process for ceramic tiles, as well as a device suitable for carrying out said process, capable of minimizing the waste of material, and in particular of the precious material used to obtain the desired aesthetic effects.

Finally, another purpose of the present invention is to make available a pressing process for ceramic tiles, as well as a device suitable for carrying out said process, largely obtainable through the use of standardized plant equipment easily available on the market. These objects and others besides are substantially achieved by a pressing process for ceramic tiles characterized in that it comprises the steps of: loading a containment body having at least one frame and at least one removable bottom wall, with a forming material, for example with powdery clay materials; introducing said containment body inside a press, for example in correspondence with a lower half-mold of said press, said lower half-mold being in a loading position; extracting the bottom wall of said containment body, positioning it externally to the press; extracting said frame, positioning it externally to the press; bringing said lower mold half into a pressing position, and pressing the forming material.

Said method provides for the use of at least one pressing device for ceramic tiles comprising a containment body for a molding material, and is characterized by the fact that said containment body comprises a frame and an extractable bottom wall, said wall bottom being mounted translatable on said frame and being movable, with respect to the frame, between a first position in which said removable bottom wall is substantially inserted in the frame, and a second position in which said removable bottom wall is substantially disconnected from the frame.

Further characteristics and advantages will become more apparent from the detailed description of some preferred, but not exclusive, embodiments of a pressing process for ceramic tiles, as well as of a device suitable for carrying out said process, made hereinafter with reference to the attached drawings, provided for indicative and, therefore, non-limiting purposes only, in which: - figure 1) represents a top view of a pressing device for ceramic tiles object of the present invention;

figure la) represents a side view of a pressing device for ceramic tiles object of the present invention, with the bottom wall disconnected from the frame of said device;

- figure 1b) represents a side view of a pressing device for ceramic tiles object of the present invention, with the bottom wall inserted by the frame of said device;

- figure 2) and figure 3) represent two different views, respectively front and side, of a pressing device for ceramic tiles object of the present invention;

- Figure 4) schematically represents the step of inserting a device object of the present invention inside the operating space of a ceramic tile press, said insertion step occurring simultaneously with the expulsion of a newly formed ceramic tile from said press;

figure 5) schematically represents the step of extracting, from the operating area of the press, the bottom wall of a feeding device object of the present invention;

- Figure 6) schematically represents the phase of depositing the ceramic powders inside the mold of a press;

figure 7) schematically represents the step of extracting the feeding device object of the present invention, now emptied of the ceramic powders and without the bottom wall, from the operating space of the press; - figure 8) and figure 9) schematically represent the pressing steps proper, relative to a process for pressing ceramic tiles object of the present invention.

With reference to the accompanying figures, the reference numeral 1 generally indicates a device suitable for carrying out the pressing process for ceramic tiles object of the present invention (see figures 1, 2, 3).

Said device 1 essentially consists of a containment body for the material or for a mixture of molding materials, for example for powdery clay materials 3.

Said containment body 1 actually acts as a tray or drawer for feeding a press for ceramic tiles, and comprises a frame 2 having a plurality of front walls 24a and side walls 24c, and a bottom wall 25 which can be extracted, mounted translatable on said frame 2 is movable, with respect to frame 2, between a first position in which said removable bottom wall 25 is substantially inserted in the frame 2 itself (see figure 1b), and a second position in which said removable bottom wall 25 it is substantially disconnected from said frame 2 (see figure n ° la).

The frame 2, possibly, can be equipped with a known internal grid, not shown in the attached figures, for example of the "honeycomb" type.

Said bottom wall 25 comprises or is integral with an anchoring portion 22 equipped with suitable guide means 23, adapted to be operatively connected with suitable and known handling and control means, not shown in the figure.

Frame 2 and bottom wall 25 are preferably both made of metallic material, for example the frame 2 can be made of steel and the bottom wall 25 of aluminum.

The bottom wall 25 must be made using all the necessary technical measures, however well known to those skilled in the art, in order to guarantee a perfect and regular planarity and dimensional stability thereof.

The reciprocal movement between the frame 2 and the bottom wall 25 is made possible, for example, by the use of special grooved guides (not shown in the attached figures) obtained directly in the body of the frame 2, for example in correspondence with its side walls 24c, in which suitably engages and disengages said removable bottom wall 25.

However, a preferred embodiment provides for the use of special ball rolling guides 26, mounted externally and parallel to the side walls 24c of the frame 2.

Said ball-rolling guides 26 are mounted integrally to the frame 2 and to the bottom wall 25 and allow the reciprocal movement between the bottom wall 25 and the frame 2 itself, minimizing friction and therefore allowing adequate operating speeds.

Said ball-rolling guides 26 also ensure perfect alignment between the frame 2 and the bottom wall 25, which is indispensable for the correct operation of said device 1.

The front walls 24a of the frame 2 define, together with the side walls 24c, the useful surface of the containment device or body 1, i.e. they define the space of the loading tray or drawer which will actually be filled with powdery clay material 3 during the process object of the present invention.

Said method first of all provides for the use of at least one device 1 of the type described above, or of one or more containment bodies or trays or feed drawers of a press for ceramic tiles, substantially constituted by at least one frame 2 having a bottom wall 25 removable, i.e. movable with respect to said frame 2.

In a preferred embodiment, the use of a plurality of containment bodies or trays or feed drawers of the type described above is envisaged.

These containment bodies 1 or trays or feed drawers, in the following of the present description may be generally indicated, for the sake of brevity, with the simple term of "trays".

Said trays (see figure 4) are generally transported, through the use of suitable and known handling means, such as for example one or more belt systems, in correspondence with a plurality of feeding stations 10, which are vault can be made by arranging in series one or more suitably equipped hoppers, for example equipped with screens, sieves, and the like.

In correspondence with said hoppers, the feeding trays are loaded with the molding material or with a mixture of molding materials, which are generally in the form of powdery clay materials 3.

The process in question provides that the ceramic tile is subjected to pressing with the upper surface, or with the visible face or useful face, facing downwards, or in correspondence with the lower half-mold of the press, while the lower surface, that is the face of laying, also known among those skilled in the art with the slang term of "brand", is facing upwards, ie in correspondence with the upper half-mold of said press.

The feeding hoppers will therefore first deposit the oxides and / or dyes in the tray, i.e. the precious materials which give the tile the desired three-dimensional aesthetic effect, and only finally the base clay, intended to constitute the body, or the structural support of the tile itself.

As a possible application example, it is possible to provide a succession of at least five feeding stations (not shown in the attached figures). In correspondence with a first feeding station, for example, on the bottom of the tray, or in contact with the removable bottom wall 25 of said tray, a silk screen in powder is poured, for example through the use of a special screen.

In a second station, a plurality of compound solids or sands, for example semi-cooked clays, fluxes, glazes, etc. are deposited on the tray by gravity.

At a third station, coloring oxides can be added, distributed randomly, in order to recreate the same aesthetic effect of the veins of natural stone.

With a fourth station it is possible to add a mixture of ceramic dyes, which give the tile its overall color. In a fifth and last station, the tray is loaded with the base clay, or with the actual molding material of the tile.

After this last loading phase, it is preferable to proceed to a subsequent shaving phase of the forming material, to ensure a homogeneous thickness of the tile and to remove any waste fractions, or excess, of the clayey material.

However, by operating on the lower surface, or on the "brand" of the tile, this and all the subsequent shaving phases of the forming material will only concern the base clay, and not the precious materials (oxides, dyes, etc.) , thus realizing significant savings. At this point at least one feeding tray or drawer of the press has been filled and is therefore ready to position itself in correspondence with the mold of said press.

Said tray 1 is therefore positioned on a suitable feeding carriage 6 of the press, generally comprising a flat and smooth surface, for example made of Teflon, or at least covered with a layer of said material, said flat and smooth surface obviously being coplanar with respect to on the press floor itself.

The press feed carriage 6 naturally comprises known and suitable handling, locking and unlocking, command and control means 9, for operatively associating said carriage with at least one, or preferably with a plurality, of feeding trays or drawers of the type described above.

Generally, it is possible to associate at least three feeding trays or drawers of the type described above to the feeding carriage of the press. By means of the feeding carriage, said trays are then introduced into the operating space of the press: this condition is for example schematically illustrated in figure 4.

In this figure, a containment body 1 or tray or feed drawer made according to the present invention is mounted on the feed carriage 6 and then inserted inside a press 4 for ceramic tiles.

Said press 4 is equipped with a mold divided into two half-molds, that is, in a lower half-mold 5a and in an upper half-mold 5b.

When the tray 1 is inserted inside the press 4, in correspondence with the lower mold half 5 a, said lower mold half 5 a is in a first position, which can for example be defined as the loading position. In this loading position, said lower half-mold 5 a is substantially at the same level as the feeding carriage 6 of the press. The insertion of the tray 1 inside the operating space of the press 4, through the feeding carriage 6, also coincides with the removal, from said operating space, of a ceramic tile 7 already formed. This is made possible since a pusher 12 is integrally associated with the feeding carriage 6 which is responsible for ejecting said already formed tile 7.

During this phase, the upper half-mold 5b is also in a first position, which can for example, in analogy with what has already been seen for the lower half-mold 5a, be defined as the loading position. In this loading position, the upper mold half 5b is suitably spaced with respect to the lower mold half 5 a, thus ensuring an adequate gap in the inlet area of the press 4 to allow easy insertion of the feeding carriage 6.

Subsequent to the loading phase of the press 4, one proceeds (see figure 5) with the rapid extraction phase of the movable bottom wall 25 of the tray 1, through the use of suitable and known handling and control means, not shown in the figure, which engage the anchoring portion 22 and the guide means 23 of the bottom wall 25.

However, it is always possible to carry out production cycles which provide for a high extraction speed of the bottom wall 25, the weight of said bottom wall 25 being very low.

Preferably, the step of extracting the bottom wall 25 of the tray 1 is carried out simultaneously, or at least almost simultaneously, with the step of inserting said tray 1 in correspondence with the lower half-mold 5a of the press 4.

In this way, if the extraction motion of the bottom wall 25 occurs in the opposite direction with respect to the previous, or rather, simultaneous movement of the entire tray 1 as it enters the press 4, a peculiar dynamic compensation effect is obtained such as to in which the ceramic powders 3 which constitute the tile to be pressed, in their fall towards the lower half-mold 5a following the extraction of the bottom wall 25 of the tray 1 (see figure 6), remain substantially composed in an ordered configuration. This dynamic compensation effect is particularly important as regards the precious materials of the tile, i.e. glazes, oxides, inclusions, etc., which are responsible for giving the tile itself three-dimensional aesthetic effects: these precious materials, being initially located in the lower area of tray 1 , in proximity to or even in contact with the back wall 25, directly benefit from the aforementioned dynamic compensation effect, depositing on the lower half-mold 5a in a composed manner and without substantial configurational changes that could compromise the quality of the aesthetic effects sought.

The step of depositing the forming material inside the lower half-mold 5 a is facilitated by the fact that said half-mold, after the extraction of the bottom wall 25, is lowered to an intermediate position, below the plane defined by the carriage feed 6 of the press 4 (see figure n ° 6): in this way, the forming material is gently deposited inside the lower half-mold 5a.

Once the powdery clay material 3 has been deposited inside the lower half-mold 5a, it is possible to extract, by means of the extraction of the feeding carriage 6, the now empty tray 1 (see figure 7); during this phase, a shaving of any forming material present in excess on the laying face, or "mark", of the tile to be pressed also takes place, by means of special shaving means 13 integral with the feeding carriage 6.

It is thus possible at this point to start the pressing cycle proper.

Generally, said pressing cycle begins by bringing the lower half-mold 5a to a third position, which we could call the pressing position (see figure n ° 8).

When the lower half-mold 5a is in said pressing position, it is able to receive the upper half-mold 5b in an optimal manner, i.e. the pressing of the forming material can take place (see figure 9) without risk of damage to the press 4 as well as for the various equipment connected to it.

Said pressing is naturally carried out by lowering the upper half-mold 5b towards a second position, or, by analogy in language, towards a pressing position, in correspondence with the lower half-mold 5a. After the pressing has been carried out, the lower and upper half-molds return to the loading configuration, i.e. to their original positions. The press 4 then opens and a new processing cycle can take place, with the entry of a new tray 1 and the simultaneous expulsion of the newly formed tile.

The timing of such a processing cycle is certainly optimized if the use of a plurality of trays is envisaged, so that the press can work in a continuous cycle, substantially following the same times usually adopted with type feeding trays. normal, ie without movable bottom wall 25.

The plurality of trays is moved by means of known and suitable material handling means, said means taking care of the transport of said trays both during the loading and unloading phases of the press, and during the filling steps of said trays through the above-described feeding stations. Power supply.

Said material handling means can be assembled according to a plurality of different plant solutions: for example, in the attached figures, reference is made to a solution which provides for the movement of said trays on two different planes, one for feeding the press and one for feeding the press. of recirculation of said trays towards the feeding stations.

However, solutions can be envisaged which provide instead of carrying out said movement of the trays on a single plane, for example along a circuit having a configuration of the "horseshoe" type, and so on.

The present invention achieves the intended purposes.

In particular, the present invention provides a pressing process for ceramic tiles, as well as a device suitable for carrying out said process, capable of obtaining high quality three-dimensional aesthetic effects, using simple equipment and realizing fast and efficient production cycles. economic, said process and said device being particularly, although not exclusively, indicated for the processing of ceramic tiles in porcelain stoneware.

The present invention also provides a pressing process for ceramic tiles, as well as a device suitable for carrying out said process, capable of minimizing the waste of forming material, and in particular of the valuable material used to obtain the desired aesthetic effects.

Finally, the present invention provides a pressing process for ceramic tiles, as well as a device suitable for carrying out said process, obtainable largely through the use of known and standardized plant equipment.

Claims (12)

CLAIMS. 1. Pressing process for ceramic tiles, characterized in that it comprises the following phases: - loading a containment body (1) comprising at least one frame (2) and at least one removable bottom wall (25) with a material or with a mixture of molding materials, for example with powdery clay materials (3); - introduce said containment body (1) inside a press (4), for example in correspondence with a lower half-mold (5a) of said press (4), said lower half-mold (5a) being in a loading position; - extracting the bottom wall (25) of said containment body (1), positioning it outside the press (4); - extracting said frame (2) of said containment body (1), positioning it externally to the press (4); - bringing said lower mold half (5a) into a pressing position; - pressing said forming material. 2. Pressing process for ceramic tiles according to the preceding claim 1, characterized in that it subsequently comprises the steps of: - open the press (4); and - remove an already formed ceramic tile (7). 3. Pressing process for ceramic tiles according to the preceding claim 2, characterized in that said step of extracting the already formed ceramic tile (7) coincides with the step of introducing the containment body (1) inside the press (4 ). 4. Pressing process for ceramic tiles according to the preceding claim 1, characterized in that the step of extracting the bottom wall (25) is carried out simultaneously, or at least almost simultaneously, with the step of inserting the containment body ( 1) inside the press (4). 5. Pressing process for ceramic tiles according to the preceding claim 1, characterized in that the step of loading the containment body (1) with the forming material provides for at least five feeding stations (10). 6. Pressing process for ceramic tiles according to the preceding claim 1, characterized in that the step of bringing said lower half-mold (5a) into a pressing position is preceded by a step of bringing said lower half-mold (5a) into an intermediate position , to gently deposit the molding material inside the lower mold half (5a). 7. Pressing process for ceramic tiles according to the preceding claim 1, characterized in that it further comprises at least one step of shaving off any excess forming material. 8. Pressing device for ceramic tiles, comprising a containment body (1) for a material or a mixture of molding materials, for example for powdery clay materials (3), characterized in that said containment body comprises: - a frame (2); and - a removable bottom wall (25), movably mounted on said frame (2), said removable bottom wall (25) being movable, with respect to the frame (2), between a first position in which said bottom wall (25) removable is substantially inserted in the frame (2), and a second position in which said removable bottom wall (25) is substantially disconnected from the frame (2). 9. Device according to the preceding claim 8, characterized in that it further comprises at least one ball rolling guide (26), said ball rolling guide (26) being mounted integrally to the frame (2) and to the bottom wall (25 ). 10. Device according to the preceding claim 8, characterized in that the frame (2) is provided with an internal grid. 11. Device according to any one of the preceding claims 8, 9 or 10, characterized in that the removable bottom wall (25) comprises or is integral with an anchoring portion (22) equipped with guide means (23), called guide means (23) being operatively connected with movement and control means. Device according to any one of the preceding claims 8, 9 or 10, characterized in that the removable bottom wall (25) is made of metallic material, for example of aluminum.