Improved apparatus and process for die filling supply, in forming of tiles or like products

Technical Field

The present invention relates to an apparatus useful, in the production process for forming ceramic tiles or like products, for die filling supply and for the discharge of the formed products. The invention also relates to a method of supply and discharge of the pressing die, in the production process for forming ceramic tiles or like products.

Background Art.

At present, as known, in the production process of ceramic tiles or concrete or resinoid mix blocks, the forming step takes place using special presses, with one or more dies, which are associated to devices and means for charging the die forming pits with the powder material intended for the composition of the various products.

Said means and devices comprise boxes or grills, essentially comprised of rectangular frames horizontally shifting in a plane arranged between the top die and the bottom die of the press, from a first "fully back" position, outside the press, where the box is filled with the powder material to be pressed, to a second "fully forward" position, right above the die pit, wherein the material contained into the box or grille is poured by gravity in said pit. Once pressed, said material is called "Body" as it constitutes most of the tile, in the case of dual or triple charging, or even the entirety of the tile in the case of single charging.

In fact, the above means and devices further comprise so-called "dual charging" devices, which operate in conjunction with the boxes described above, to discharge into the die pit a second layer of material having thickness and composition differing from the previous layer, for example intended for

decorating the tiles. These devices are essentially comprised of further boxes, screens or belt conveyors sufficiently long to ensure the laying, on their top surface, of subsequent layers arranged at predetermined distances and in a suitable number for withstanding the pressing rates that can be actuated with the forming press, said belt devices being further provided with an end portion horizontally shifting up to reach an "fully forward" position on the die pit and retractable according to such speeds and times as to allow as whole as possible a transfer of the layers from the belt to the pit itself.

Disclosure of the Invention

The object of the present invention is to propose an apparatus which should allow supplying the press dies, in the forming process of ceramic tiles or like products, with a simplification of the means and of the devices described above, and which should further ensure, without structural changes or variations, both the charging of a single layer "body" of large thickness (10-30 mm), or if the single tile is multilayer, of multiple additional layers in dual or triple charging of the same die pit.

A further object of the invention is to propose a method for supplying press dies, for forming and discharging the formed products, which should be carried out in a flexible and reliable manner by simplified means and devices and digitally inputted operating parameters.

The above and other objects are achieved by an apparatus for die filling supply and for discharging the products formed in the forming process of ceramic tiles or like products, said apparatus being characterised in that it comprises a belt conveyor having sufficient length for laying, on the top surface of said belt, layers of powder material, at such distances and number as to sustain the rates and the way of loading the material into the pit, or pits of the press die, an end portion of said belt conveyor being advanceable and retractable, from an "fully back" position, outside the press, to an "fully forward" position, inside the press, of charging of said pit, or pits, and vice versa, means for ejecting the formed

products, 5, for levelling, 2, and shaving, 4a and 4b, the powder material laid, being provided according to the following claims.

Suitable devices intended for laying the various layers of powder material on the top surface of the belt conveyor are associated to the conveyor itself and positioned above the belt according to distances from each other useful for causing the deformation, on said surface, of layers of powder material in such number and arrangement as to supply the pressing dies in a manner consistent with the type of products to be formed.

As said, such products may be made up of a single layer of powder materials or multiple layers intended for forming, for example, the main body of the tile, that is, the body, and the decoration surfaces of the same, said surfaces being arranged at the bottom or at the top in the tile being formed.

A method of supply of the pressing dies, in the process for forming ceramic tiles or like products, envisages: - laying layers of powder materials in distinct positions on the top surface of a single belt conveyor,

- advancing an end portion of said belt conveyor to the zone comprised between top die and bottom die, above the pits of said pressing dies with, in the case of forming large thickness body layers, the partial release of precharge powder in the front portion of the pits themselves,

- retracting said end portion with the concurrent release of the layer, layers or residual portion thereof, in the case of previous precharge, of material supported, in the underlying pit(s), and in the case of forming of tiles comprised of various layers provided in distinct positions on the top surface of a single belt conveyor,

- repeating the advancement and retraction steps of the end portion of said belt conveyors, for each additional layer of material to be laid in said pits and constituting the single tile(s).

The method advantageously envisages that, during one or all the advancement steps of the end portion of said belt conveyor in the zone comprised

between top die and bottom die, the products formed with the previous forming cycle are also ejected, and that during the retraction step(s) of said end portion, the material released from the belt into the pit is preferably levelled and shaved.

During one or all the steps of advancement of the end portion of said belt conveyor in the zone comprised between top die and bottom die, the top (Ss) and bottom (Si) surfaces of the die forming bods can further take place.

The advantages compared to traditional apparatus and methods used for changing die pits in the forming process of ceramic tiles or the like appear clearly from the features described above, especially in relation to the simplification of the machines and equipment associated to the forming presses and also in relation to the flexibility and reliability of the pit charging method actuable in the manner outlined above.

Brief Description of the Drawings Further advantages of the present finding will appear more clearly from the following detailed description of a preferred but non-exclusive embodiment of the finding itself, illustrated by way of a non-limiting example in the annexed drawings, wherein:

- Figure 1 shows a schematic longitudinal section view of a die supply apparatus according to the invention with the indication of the possible motions for the different main elements constituting the system;

- Figure 2 shows a schematic longitudinal section view of a die supply apparatus and of the dies themselves according to the invention with the indication of the possible motions for the different main elements constituting the system and the first step of a possible tile forming cycle always according to the invention;

- Figure 3 shows a schematic longitudinal section view of a die supply apparatus and of the dies themselves according to the invention in a second and third step of a possible tile forming cycle always according to the invention;

- Figure 4 shows a schematic longitudinal section view of a die supply apparatus and of the dies themselves according to the invention in a fourth and

fifth step of a possible tile forming cycle always according to the invention;

- Figure 5 shows a schematic longitudinal section view of a die supply apparatus and of the dies themselves according to the invention in a sixth and seventh step of a possible tile forming cycle always according to the invention; - Figure 6 shows a schematic longitudinal section view of a die supply apparatus and of the dies themselves according to the invention in an eighth and ninth step for completing the supply of the die pits in a possible forming cycle of the single layer tile always according to the invention;

- Figure 7 shows a schematic longitudinal section view of a die supply apparatus and of the dies themselves according to the invention in a tenth and eleventh step for completing the supply of the die pits in a possible forming cycle of the multilayer tile always according to the invention;

- Figure 8 shows a schematic longitudinal section view of a die supply apparatus and of the dies themselves according to the invention in a twelfth and thirteenth step of another possible forming cycle of the multilayer tile always according to the invention;

- Figure 9 shows a schematic longitudinal section view of a die supply apparatus and of the dies themselves according to the invention in a fourteenth and fifteenth step of another possible forming cycle of the multilayer tile always according to the invention.

Detailed Description of the Preferred Embodiments of the Invention

With reference to Figure 1, reference numeral 10 indicates an apparatus for supplying pressing dies, in this case used in the forming process of multilayer ceramic tiles, 3, which during the forming have the exposed decorated portion at the top.

With reference to Figures 1 and 2 of the Italian patent application

MO2005A000106 filed by the same Applicant, apparatus 10 is comprised of a belt conveyor associated to devices, 13, arranged above the belt 12, at predetermined distances, for laying onto the same the layers 14 of powder material intended for

making the tiles.

In particular, the end portion 15 of said belt conveyor is horizontally shifting with the aid of special means 16 of the prior art, described and illustrated, for example, in European patent 1 175 985 issued to the same Applicant, towards the zone arranged between the top die 18 and the bottom die 19, comprising pit 20, wherein the powder material carried by said belt 12 is discharged.

With reference to Figure 1, said end portion 15 of the belt conveyor, forming a front unit Ga, is connected to one or more cross bars 2, 4, 5 arranged at the front of the mobile front edge 22 of belt 12, by the aid of connection and support arm 23, constrained to the two sides of the belt itself. Said cross bars 2, 4, 5 comprise a first known ejection portion 5, arranged in a more advanced position and suitable for pushing tiles 3, once formed, from the die towards a roller conveyor arranged in front of the die itself, in a position opposite the belt conveyor, and a second portion 2 and 4, in innermost position, and respectively suitable for the optional levelling and shaving of the powder layer laid on the end portion of the belt conveyor 15 into pit 20.

With reference to the enlarged detail of Figure 5A, the powder levelling element(s) 2 is/are generally fixed and they allow suitably and constantly profiling the powders along a powder levelling surface Pl, above the die surface Ps, so as to allow optimum subsequent shaving of powders, at the die surface Ps, by the shaving element 4, since the same is provided at the bottom with a special doctor, 4b, sliding in abutment on the die surface Ps. The powder levelling elements 2 may be in various amounts and shapes with, as highlighted in the example, suitable bottom profiling with plane inclined upwards by an angle i. The powder levelling elements 2 allow reducing the initial collection of shaving Ar, optimising the shaving itself.

Always with reference to Figure 1, said end portion of the belt conveyor 15, always belonging to the front unit Ga, and usually between the cross bars 4 and 5, there may be a motor driven system 6 for cleaning the surfaces of the top Ss or bottom Si forming bods generally comprised of a revolving brush 6s and relevant

motor means 6m.

The method of supplying the pressing dies and discharging the formed products, carried out with the apparatus described above, can be illustrated in particular in the examples illustrated in Figures 2 to 9, for obtaining multilayer tiles that in this case are the result of two cycles of advancement and retraction of the end portion of the belt conveyor 15, and in Figures 2 to 6 for obtaining single layer tiles that are the result of a single cycle of advancement and retraction of the end portion of the belt conveyor 15. It is clear that repeating the insertion and retraction steps before carrying out the forming of the tiles it is possible to obtain multilayer tiles comprised of further additional layers.

Figure 2B and Figure 3 A show the step wherein a body layer 14 of powder material previously laid on belt 12 by a special body charging device 13 is led to the zone comprised between top die 18 and bottom die 19, thanks to the advancement of the end portion of the belt conveyor 15 and of belt 12 itself. In this step, thanks to the advancement motion of the above end portion 15, and of the suitable ejection means 5, integral thereto, the die of the tile(s) formed with the previous pressing cycle is ejected. In this step, according to the prior art, the top forming surface Ss of the top die 18 is also cleaned by the revolving brush 6s and the bottom forming surface Si of the bottom die 19 by the mobile shaving element(s) 4. It is clear that, according to the prior art, in the case of production of tiles with tile exposed side arranged at the bottom, during the forming the revolving brushes 6s, the revolving brushes 6s are movable and in this step they clean the bottom forming surface Si of the bottom die 19.

Figure 3B and Figure 4A illustrate the step wherein, having an advancement speed of belt 12 greater than the advancement speed of the end portion of the belt conveyor 15, the large thickness body layer advances relative to the end portion of the belt conveyor 15, and starting from half die onwards, it ends into the front portion of the die pit. In this way, the front portion of the die pit itself is precharged. This precharge is required to have an optimal filling of the contact zone of pits C with the bottom die 19, with a reduced collection of initial powder

Ai ₅ on the die surface Ps, and consequent reduced size of the levelling Al, and above all shaving Ar accumulations, as highlighted in the detail of Figure 4B and Figure 5A.

At the end of the pit levelling and shaving, the residual excess powders Pr on the die surface Ps are conveyed into a recovery hopper Tr, as highlighted in Figure 5B and Figure 6A.

Afterwards, the end portion of the belt conveyor 15, and the entire front unit Ga, integral thereto comprised of portions 2, 4, 5 and 6 reaches the "fully back" position with the relevant overall dimensions outside the press die as highlighted in Figure 6B.

As already said, in the case of production of single layer tiles, the cycle then ends with the pressing and the extraction of the formed tile 3 from the tile pit, as highlighted in Figure 9A and Figure 9B. In particular in Figure 9B it is seen that the tile(s) thus formed are led to a position useful for the ejection from the die by the end portion of the belt conveyor 15, and by the suitable ejection means 5 integral thereto, by a suitable lifting stroke of the bottom forming surface Si.

In the case of production of multilayer tiles, on the contrary, subsequently there will be subsequent steps of insertion and retraction for each of the additional layers of smaller thickness, Sai, constituting the single tile(s), with their laying inside the die pit as highlighted in Figure 7A, Figure 7B, Figure 8A and Figure 8B. With reference to Figure 8 of the Italian patent application MO2005A000106 filed by the same Applicant, it is clear that if the Sai need not be laid at the beginning of the highlighted supply cycle, levelling and shaving are carried out for the last "body" layer charged into the die pit(s) at the cycle end. Afterwards, as said, are the common steps of pressing and extraction of pressed tiles 3, highlighted in Figure 9 A and Figure 9B.

Thus, thanks to the apparatus and method described above it is possible to provide to the process for forming ceramic tiles or concrete or resinoid mix blocks or like products, using simplified machines while having large production flexibility. In fact it is possible to produce tiles or the like either single layer or

multilayer easily switching from one to the other production. It is also clear that said advantages are safeguarded even if changes and variations are made to the example of embodiment described above.

For example, the length and shape of the belt conveyor may change according to the type of products to be made and as a consequence, the number and arrangement of devices 13 suitable for laying the various layers of material on the belt may vary. Also the shape of the front unit Ga may change, as the function of shaving of the powder material laid may be integrated or modified or the means for cleaning the forming surfaces 6 may be lacking. Moreover, in executing the forming process with the apparatus of the invention, or in a single step of advancement/retraction of the end portion of the belt conveyor, the material shaving step may be not provided, as for example in the case of forming of tiles having a decoration layer(s) at the top, the overall height whereof is less than the depth of the pit as highlighted in Figure 9A. It is clear that other changes may be made to the means intended for shaving or advancing and retracting the end portion of the belt conveyor, as the means for receiving the formed products upon their ejection from the die may be various. Of course, other practical-application changes of the construction details can be made to the finding without departing from the scope of the inventive idea as claimed hereinafter.