The present invention relates to the technical field of manufacturing slabs made of an aggregate of stone material and/ or ceramic material and/ or sintered stone from at least one mix.

In particular, the present invention relates to an apparatus for performing inclusions and/ or veins in slabs manufactured from at least one base mix and at least one additional mix.

In particular, the inclusions in the slabs are obtained from mounds of additional mix and the veining in the slabs is obtained from a dye in liquid or powder form.

The base mix and the additional mix are intended to undergo at least one compaction step for producing the slabs, in particular for producing slabs with veining.

The additional mix has at least an external appearance and a colouring different from those of the base mix.

The present invention also relates to a plant for manufacturing slabs, in particular slabs with a veining effect, comprising the aforementioned apparatus, and to a method for performing inclusions in the slabs.

The manufacture of slabs consisting of an aggregate of stone material and/or ceramic material and/or sintered stone from a base mix has been known for some time; said manufacture involves, for example, the use of Bretonstone® technology, which is widely known in the field.

The machines and the apparatus used to produce slabs from a mix generally comprise a distribution device for distributing a base mix in one or more temporary supports, such as moulds or trays.

The base mix comprises mainly a stone and/or stone-like material and/or ceramic material and/or sintered stone in powder and/ or granulated form and a binder, for example a binder of the inorganic type or a hardening resin.

The distribution device may be formed by a hopper which is designed to contain a predetermined quantity of mix to be distributed in the temporary supports and by an extractor belt which is designed to receive the mix from the hopper and distribute it inside the temporary supports which are in relative motion with respect to the distribution device.

These machines may also comprise one or more dispensers for dispensing a dye onto the mix so as to produce slabs with dye inclusions which have a particular veined effect.

In particular, these dye dispensers are positioned above the extractor belt so as to distribute one or more dyes, in liquid or powder form, over the base mix before the latter is distributed inside the temporary supports.

The machines and the apparatuses described above, although widely known and popular in the field, are not without a number of drawbacks.

A first drawback is that the distribution of the dye on the mix is performed in a random manner. This drawback therefore prevents the production of slabs with inclusions, in particular veining, having a predefined profile or design.

Another drawback consists in the fact that these machines and these apparatus do not allow the formation of veining in slabs having a variable length, nor a stained veining effect, namely with predefined areas having colour tones or shading different from those of the rest of the slab.

In order to overcome these drawbacks, the machines described above have been designed with one or more working heads each comprising a tool for working the mix and a device for dispensing a liquid or powder dye.

In particular, the working tool may consist of a V-blade or a furrowing tool and is intended to form grooves in the thickness of the mix distributed beforehand on the temporary support.

The dye is distributed by the dispenser inside the grooves formed beforehand by the working tool in order to form the inclusions, in particular the veining.

An example of these machines is described in the document WO2016/113652; the machine described there comprises, in addition to the V-blade, also a mixer for mixing up the mix in the zones where the liquid or powder dye was previously dispensed.

Another example of this further type of machine is described in the document US2019/0143743; the machine described there is intended for the production of slabs made of artificial quartz with a veined effect from a mix.

In particular, this machine comprises a series of sections or portions each provided with different working tools, such as rollers, plates with projections, plates with inset grooves, knives, rollers and V-blades.

These working tools allow the formation of grooves with widths which are smaller and different from each other in the base mix or in the semi-finished slab; the machine also comprises a further section located downstream of the preceding sections and having a spray unit for distributing a dye inside the grooves.

However, these solutions are not without a number of drawbacks.

A first drawback consists in the fact that these further machines do not allow the formation of inclusions and/or veining with particularly large widths, for example in the region of several tens of centimetres, while having a clear and well-defined colour with respect to the base mix.

Another drawback consists in the fact that the width of the veining which can be made may vary only within a limited range of values of between 2 mm and 20 mm.

In order to further overcome these latter drawbacks machines and apparatus have been developed where the dye distributed inside the grooves in order to perform the inclusions or the veining is formed by a mix similar to the base mix, but having a colour and appearance different from those of the base mix; said mix is also referred to as an additional mix or colouring mix or veining mix.

An example of these machines is described in the patent application W02020/115644. The machine disclosed in this patent application comprises at least one tool for working the base mix in order to form the grooves and at least one dispensing device for distributing the additional mix inside the grooves, the additional mix being designed to form the inclusions or the veining in the finished slabs.

The at least one working tool and the at least one dispensing device are located on working heads in turn mounted on anthropomorphic robotic arms.

One drawback of this latter solution is that the overall time for the manufacture of the slabs is particularly long.

A further drawback is that this latter solution allows the width of the veins in the slabs to be increased only by a small amount and does not allow veining with clear and well-defined contours to be formed.

Another example of use of an additional mix such as a dye for performing the inclusions and the veining in the slabs is described in patent application W02019/101823.

In particular, in this latter document, the system for distribution of the mixes and production of slabs from the mixes uses a filling template designed to be positioned inside the temporary supports.

Said filling template comprises a plurality of shaped profiles which extend from the rigid frame and define a plurality of areas outside the profiles; these external areas are delimited by the frame and by the same profiles.

The use of the system described in W02019/101823 involves substantially the following steps:

- positioning the filling template inside a temporary support;

- distributing by means of a distributor a base mix in the areas of the filling template outside the profiles and thus outside the areas intended to form the inclusions and the veining;

- compressing the base mix by means of a pressing cover placed in contact with the top surface of the base mix;

- removal of the filling template from the temporary support so as to obtain a layer of base mix provided with grooves corresponding to the profiles of the filling template;

- distribution of an additional mix inside the grooves, the additional mix being designed to form the inclusions and/ or the veining in the slabs at the end of the production process.

Then, the base mix and the additional mix distributed in the temporary support are subjected to a vacuum vibrocompression step and a hardening step in order to complete the production of the slab.

A second example is described in WO2016/189377 which, similar to the preceding example, involves the use of inserts positioned in the temporary support before distribution of the base mix.

Following the distribution of the base mix, the inserts are removed from the temporary support and the grooves left free by the inserts are filled with a fluid mixture of a further material, comparable to an additional mix, for forming thick veining.

The method described in WO2016/189377 furthermore involves the formation of grooves with a smaller width and thickness in the surface layer of the base mix, preferably by means of projections fixed to a covering element and designed to penetrate into the base mix.

These grooves are filled with a fluid mixture of a further material different from the base mix.

These latter solutions have the following drawbacks:

- in the first solution, the particular configuration of the filling template prevents the base mix from flowing along the sides of the profiles; this drawback prevents the formation of veining having a greater width than the veining formed using the other methods known from the present state of the art;

- the subsequent distribution of the mix in addition to the base mix does not allow veining with clear contours to be obtained in the slabs;

- there is no uniform distribution of the base mix and the additional mix in the areas respectively outside the profile and inside the grooves formed in the base mix layer;

- in the first solution, the step of compressing the base mix results in an accumulation of said mix alongside the zones previously occupied by the profiles; this drawback renders the following vibrocompression step critical, with the possible risk of defects being formed on the slabs.

The main object of the present invention is to provide an apparatus and a method for performing inclusions and/ or veining in slabs manufactured from a base mix and from an additional mix and a plant for manufacturing slabs which are able to solve the aforementioned drawbacks.

A particular task of the present invention is to provide an apparatus and a method of the type described above which allow the formation of inclusions and/or veins having both greater widths/thicknesses and smaller widths / thicknesses.

Another task of the present invention is to provide an apparatus and a method of the type described above which allow the formation of inclusions and/or veining having contours which are clear and well- defined with respect to the slab body.

A further task of the present invention is to provide an apparatus and a method of the type described above which are able to reduce the overall time required for manufacture of the slabs.

Another task of the present invention is to provide an apparatus and a method of the type described above which are able to ensure particularly effective vacuum compaction of the mixes for producing the slabs, without the risk of causing defects on the slabs.

A further task of the present invention is to provide an apparatus and a method of the type described above which are able to distribute the mixes in a uniform manner on the temporary supports.

A further task of the present invention is to provide an apparatus of the type described above which has a limited complexity and production costs which are less than those of the apparatus known in the sector.

The main tasks and object described above are achieved with an apparatus and a method for performing inclusions in slabs manufactured from a base mix and from an additional mix in accordance with Claim 1 and Claim 23, respectively, and with a plant for manufacturing slabs according to Claim 22.

In order to illustrate more clearly the innovative principles of the present invention and its advantages compared to the prior art, an example of embodiment of the apparatus according to the present invention will be described below with the aid of the attached figures. In particular, in the figures:

- Figure 1 is a schematic front view of the apparatus for performing inclusions and/ or veining in the slabs according to the present invention and comprising a first embodiment of a unit for distributing a liquid or powder dye;

- Figure 2 is a perspective view of some of the components of the apparatus shown in Figure 1;

- Figure 3 is a schematic front view of the apparatus for performing inclusions and/ or veining according to the present invention, comprising a second embodiment of the unit for distributing the liquid or powder dye;

- Figure 4 is a perspective view of some of the components of the apparatus shown in Figure 3;

- Figures 5 and 6 are perspective views of two components of the apparatus shown in Figures 1 and 3 in the configuration engaged with each other and disengaged from each other;

- Figures 7 and 8 are front views of a station of the apparatus for distributing a base mix in accordance with, respectively, a first embodiment and a second embodiment;

- Figures 9-12 are front views with respective enlarged details of a station of the apparatus for distributing an additional mix, which is also visible in Figures 1 and 3, in different operating configurations;

- Figures 13-16 are front views with respective enlarged details of the station of the apparatus for distributing the base mix also shown in Figures 1, 3 and 7 in different operating configurations;

- Figures 17-19 are perspective views of further components of the apparatus, visible also in Figures 1, 3 and 9-12.

The present description, provided solely by way of a non-limiting example of protection of the invention, relates to an apparatus for performing inclusions and/ or veining in slabs manufactured from at least one base mix M2 and from at least one additional mix Ml.

In particular, the inclusions and/ or the veins in the slabs may be obtained from:

- mounds C of additional mix Ml distributed on at least one temporary support and intended to create veining beads formed in the base mix M2;

- a liquid or powder dye D distributed in areas of the base mix M2 inside the temporary support, in particular inside grooves F formed in the base mix M2;

As explained further below, the inclusions and/ or veining formed by using the liquid or power dye D have lengths and widths smaller than the inclusions and/ or veining formed using the additional mix Ml. The base mix M2 and the additional mix Ml are intended to undergo successively and/ or simultaneously at least one compaction step for production of the slabs. The base mix M2 is intended to form the solid body of the slabs at the end of the production process, as known from the prior art.

The slabs are made of an agglomerate of stone material and/or ceramic material and/or sintered stone and the mixes comprise granulates and/ or fragments and/ or powders of stone material and/ or ceramic material and/ or sintered stone and a hardening binder.

In this connection, the mixes Ml and M2 described above are intended to undergo also a binder hardening step for the production of the slabs, as further described below with reference to the slab manufacturing plant.

Furthermore, the additional mix Ml differs from the base mix M2 mainly owing to the colour and the external appearance; these features also define the tonality and the external appearance of the inclusions, namely the veining, present in the finished slabs.

However, the additional mix Ml and the base mix M2 may also differ from each other in terms of composition or chemical/ physical features, without thereby departing from the scope of protection of the present invention.

The apparatus 1 of the type described above is denoted overall by the reference number 1 in the attached figures and implements a method, also described in the continuation of the present description, for performing inclusions and/or veining from mounds C of additional mix Ml and/or from the liquid or powder dye D, in the slabs.

Furthermore, the apparatus 1 may be preferably provided in a plant for manufacturing slabs, in particular for manufacturing slabs with a veined effect; said plant forms a further subject of the present invention and is not shown in the attached figures.

In a manner known per se the plant comprises, downstream of the apparatus 1 according to the present invention, a station for compaction of the base mix M2 and of the additional mix Ml previously distributed on at least one temporary support 2, a station for performing the hardening of the mixes Ml, M2 and a transportation line for transporting the at least one temporary support 2 between the apparatus 1 and the compaction and hardening stations.

Preferably, the compaction of the mixes Ml, M2 in the corresponding station is performed by means of vacuum vibrocompression. The station for hardening the binder of the mixes may comprise a catalysis oven in the case where the binder consists of a resin. Furthermore, the transportation line may comprise one or more conveyor belts and at least one shuttle.

The compaction station and the hardening station of the plant are not shown in the attached figures, while the transportation line 3 is shown only partially in the attached figures and limited to the apparatus 1, as can be seen in Figures 1 and 3.

In particular, the movement means 10 of the apparatus 1 described below represent the portion of the transportation line 3 visible in the attached figures.

Preferably, these movement means 10 comprise a series of conveyor belts 12 for feeding the temporary supports 2 along a feeding direction and defining a substantially horizontal support surface for the temporary supports 2 being fed.

As mentioned, the apparatus 1 comprises and uses at least one temporary support 2 for distributing the mixes, namely the additional mix Ml and the base mix M2. Advantageously, the temporary support 2 may be formed by a tray or by a mould made of rubber or elastomeric material.

The apparatus 1 further comprises a first station 6 for distributing the at least one additional mix Ml on the at least one temporary support 2, a second station 8 for distributing the at least one base mix M2 on the at least one temporary support 2 and the means 10 for moving the temporary support 2 between the fist distribution station 6 and the second distribution station 8.

In particular, one or more layers of base mix M2 are distributed on the at least one temporary support 2 at the second distribution station 8 in quantities such as to obtain the desired thickness of the slab to be formed following the compaction step.

The first station 6 is shown in detail in different operating configurations in Figures 9 to 12.

A first embodiment of the second distribution station 8 is shown in Figure 7; a second embodiment of the second distribution station 8 is shown in Figure 8. Figures 13-16 show various operating configurations in sequence of the second distribution station 8 shown in Figure 7.

The at least one temporary support 2 has, inside it, in particular at the first distribution station 6, at least one recess 9 and areas 11 outside the at least one recess 9.

As shown more clearly for example in Figures 9, 10 and 17, in the first distribution station 6 the at least one temporary support 2 has inside it a plurality of recesses 9 and areas 11 outside the recesses 9.

In accordance with the present invention, the first distribution station 6 comprises means 14 for distributing the at least one additional mix Ml inside the at least one recess 9, in an amount proportional to the imprint of the at least one recess 9, so as to form at least one mound C of additional mix Ml corresponding to the at least one inclusion and/ or veining to be obtained in the slab.

In particular, the quantity of additional mix Ml to be distributed inside the at least one recess 9 corresponds substantially to the volume of the recess 9.

In the embodiment shown in the figures which has a plurality of recesses 9, the means 14 are designed to distribute the at least one additional mix Ml inside said recesses 9 so as to form a plurality of mounds C, and therefore inclusions and/ or veining to be obtained in the slabs, from the additional mix Ml.

Furthermore, the second distribution station 8 comprises means 16 for distributing the base mix M2 inside the areas of the temporary support 2 corresponding to the areas 11 outside the at least one recess 9, or recesses 9, in an amount proportional to the imprint of these areas 11.

In order to realize the configuration described above, the first distribution station 6 is positioned upstream of the second distribution station 8 so that the mounds C of additional mix Ml are distributed and formed before distribution of the base mix M2 on the at least one temporary support 2, as shown in Figures 1 and 3.

As already mentioned, the mounds C of additional mix Ml are intended to form veining beads of additional mix Ml in the base mix M2, and consequently to form the inclusions and/or the veining in the slabs following the compaction step. In this preferred embodiment, the additional mix Ml is also defined as the veining mix.

Moreover, in this embodiment the recesses 9 of the at last one temporary support 2 are formed by a plurality of grooves 9 and the distribution means 14 of the first distribution station 6 are designed to distribute the at least one additional mix Ml inside the grooves 9 so as to form a plurality of mounds or beads C of additional mix Ml corresponding to the inclusions and/ or veining to be obtained in the slabs. The veining thus obtained has a greater width and thickness than the veining obtained with the methods known in the sector, as well as well-defined and clearly marked edges.

However, the inclusions to be formed in the slabs may also be different from the veining and may also have a form which is not elongated.

Advantageously, the apparatus 1 comprises at least one filling template 4 (see Figures 1, 3, 9 and 11-12) intended to be positioned on the at least one temporary support 2, in particular at the first distribution station 6.

The temporary support 2 and the filling template 4 are shown more clearly combined with each other in Figure 17 and Figure 19.

Advantageously, the filling template 4 may be made of plastic, metallic, composite or other similar material.

The at least one filling template 4 comprises pairs of shaped profiles 7 arranged adjacent to each other and designed to delimit and define respective recesses or grooves 9, of the type described above with reference to the temporary support 2 (see in particular the enlarged details in Figures 9, 10 and 11 and Figures 17 and 19).

In particular, the pairs of profiles 7 extend from a peripheral frame 5 and the areas 11 outside the grooves 9 are defined between the frame 5 and the profiles 7.

In an embodiment not shown in the figures, the filling template 4 may comprise only one groove 9 formed by a single pair of profiles 7, so as to form a single veining in the finished slab.

Furthermore, in accordance with an embodiment not shown in the figures, the template may also be formed by a continuous panel in which on or more shaped openings corresponding to the recesses or grooves are formed.

With reference to the features of the filling template 4 indicated above, the distance between the adjacent profiles determines the widths of the grooves 9 and therefore the width of the veins which can be obtained in the finished slabs.

The width of the inclusions and/ or veining which can be obtained by using the additional mix Ml is preferably between 10 mm and 300 mm.

The thickness of the inclusions and/or veining which can be obtained by using the additional mix Ml is preferably equal to the thickness of the slab and is preferably between 5 mm and 40 mm. The recesses and the grooves 9 have irregular shapes so that the inclusions and the veining which can be obtained in the slabs reproduce the natural veined effect which is commonly present in natural stone.

Advantageously, the adjacent profiles 7 are mounted on the filling template 4 with a predefined inclination relative to the vertical direction, so as to converge upwards slightly.

This feature favours the removal of the filling template 4 from the temporary support 2 before distribution of the base mix M2 and prevents the edges of the mounds and the beads C of additional mix Ml from collapsing before distribution of the base mix M2, the sides being inclined as shown in Figure 12.

Furthermore, the at least one filling template 4 may comprise a series of spacing elements 18 positioned inside the grooves 9 and having ends fixed to the adjacent profiles 7.

These spacing elements 18 are more clearly visible in Figures 17 and 19 and allow the structure of the shaped profiles 7 to be made more rigid. These last two embodiments relate in particular to the production of slabs provided with veining.

Alternatively, the filling template 4 may comprise one or more recesses delimited by respective profiles and having an irregular shape different from the grooves 9 described above.

This alternative configuration allows the distribution of mounds C of additional mix Ml having a shape different from the beads of additional mix Ml and therefore the formation of inclusions in the slabs having different shapes and a different distribution.

According to a further embodiment not shown in the figures, the filling template 4 may comprise in combination both profiles 7 designed to delimit recesses 9 and profiles 7 designed to delimit grooves 9. The means 14 for distributing the additional mix Ml in the first station 6 may comprise a container 26 with a bottom opening 28 which can be selectively closed in order to allow discharging and distribution of the additional mix Ml, as shown in Figures 1, 3 and 9-12.

In the embodiment shown in the figures, the container 26 is mounted on the end of robotic arm 30 movable above the conveyor belt 12 of the movement means 10 of the first station 6.

Alternatively, the robotic arm 30 may also be replaced with movement devices of the Cartesian type known in the sector.

The container 26 may optionally comprise internally a rotating arm scraper, not shown in the figures, for favouring discharging of the additional mix Ml; furthermore, the container 26 may comprise a series of devices, not shown in the attached figures, for controlling the weight of the mix to be distributed inside the recesses or grooves 9.

Advantageously, the first distribution station 6 uses at least one pressing cover 20 designed to be engaged with the at least one filling template 4 for pressing and partially compacting the mounds or beads C of additional mix Ml distributed inside the recesses or grooves 9.

This feature gives the mounds or beads C of additional mix Ml a consistency such that they maintain their shape and prevents them from collapsing along their edges before distribution of the base mix M2. The pressing cover 20 is shown separately in Figure 18 and in combination with the filling template 4 and the temporary support 2 in Figure 19.

As shown in Figures 9-12, the at least one pressing cover 20 preferably comprises a series of projections 22 having a profile corresponding to and/or complementing and mirroring the profile of the at least one recess 9 or the grooves 9.

These projections 22 may have a series of incisions 24, of the type shown in Figure 18, which are arranged in positions corresponding to the positions of the spacer elements 18 of the shaped profiles 7 defining the grooves 9.

This configuration allows the projections 22 to be inserted inside the grooves 9 so as to perform pressing of the mounds C of additional mix Ml inside the grooves 9.

The first station 6 of the apparatus 1 comprises, in addition to the means 14 for distributing the additional mix Ml, means for positioning the at least one filling template 4 on the at least one temporary support 2 before distribution of the additional mix Ml inside the at least one recess 9 or inside the grooves 9.

In particular, these positioning means are designed to move the filling template 4 from a raised inoperative position with respect to the temporary support 2 (see for example Figures 1, 3 and 12) into a lowered operative position where the filling template 4 is positioned on the temporary support 2, and vice versa. This latter operative position is shown in Figures 9-11.

Furthermore, the first station 6 may comprise means for positioning and pushing the pressing cover 20 against the filling template 4; in this position the projections 22 are inserted inside the recesses or grooves 9 after the additional mix Ml has been distributed inside them, so as to press and/ or compact partially the mix Ml. This operative position is shown in detail in Figure 11.

In particular, these further positioning means are designed to move the pressing cover 20 from a raised inoperative position (see for example Figures 1, 3, 9, 10 and 12) into the lowered operative position in which the pressing cover 20 is in contact with the additional mix Ml and presses it against the profiles 7, as shown in Figure 11, and vice versa.

The means for positioning the at least one filling template 4 and the pressing cover 20 are not shown in the attached figures.

As shown in Figures 1 and 3, the apparatus 1 may also comprise a station 32 for spraying coloured paint onto the mounds or onto the beads C of additional mix Ml, in particular onto their sides. The spraying station 32 is situated between the first distribution station 6 and the second distribution station 8.

Therefore, the painting of the mounds or beads C of additional mix Ml is performed following distribution and pressing of the mounds or beads C of additional mix Ml on the temporary support 2 and before distribution of the base mix M2 on the temporary support 2.

Furthermore, before transferring the at least one temporary support 2 with the mounds C of additional mix Ml from the first distribution station 6 to the spraying station 32, the filling template 4 and the pressing cover 20 are brought into their respective inoperative positions and then separated from the temporary support 2.

As shown in Figures 1 and 3, the spraying station 32 preferably comprises one or more spraying nozzles 33 mounted on a head 35 which is supported in turn by a robotic arm 37 of the anthropomorphic or Cartesian type.

Then the temporary support 2 with the mounds C of additional mix Ml, which may be painted, is transferred to the second distribution station 8.

The second distribution station 8 uses at least one element 34 for covering the at least one mound or mounds C of additional mix Ml distributed beforehand on the at least one temporary support 2.

This covering element 34 preferably comprises a series of U-shaped profiles 36 which are fixed to a support structure 38 and correspond to the mounds C of additional mix Ml distributed on the temporary support 2 (see in this connection Figures 1, 3, 5-6 and 16 and the enlarged details of Figures 7, 8 and 13), as described more fully below.

The second distribution station 8 is provided with means for positioning the covering element 34 over the mounds C of additional mix Ml, designed to move the covering element 34 from a raised inoperative position into a lowered operative position, and vice versa.

In the operative position, shown in Figures 13-15, in particular in the enlarged detail of Figure 15, the U- shaped profiles 36 cover and enclose the respective mounds or beads C of additional mix Ml.

Furthermore, in this operative position the U-shaped profiles 36, when they come into contact with the mounds C, exert a pressure on them and push the additional mix Ml along its walls.

The means for positioning the covering element 34 are not shown in the attached figures.

The covering element 34 is kept in the operative position until the base mix M2 has been distributed, by the distribution means 16 of the second station 8, into the areas of the at least one temporary support 2 corresponding to the areas 11 outside the mounds C covered by the covering element 34, namely outside the recesses 9.

The presence of the covering element 34 in the temporary support 2 during the distribution of the base mix M2 prevents the distribution of the latter on the mounds C of additional mix Ml, so that the inclusions and the veining remain clearly visible in the finished slabs.

Moreover, the U-shaped profiles 36 of the covering element 34 allow the mounds C of additional mix Ml to be further compacted before distribution of the base mix M2.

In this connection, the U-shaped profiles 36 of the covering element 34 preferably have an internal height which is slightly less than the height of the mounds C of additional mix Ml and an internal width slightly greater than the width of the beads C of additional mix Ml.

In accordance with an embodiment not shown in the figures, the profiles of the covering element 34 may also have a shape different from that described above, in particular in the case where the mounds C have a different shape.

Optionally, in accordance with an embodiment not shown in the figures, the positioning of the covering element 34 with the U-shaped profiles 36 for the further compaction of the mounds C may be performed before spraying with paint the mounds C formed by means of the nozzles 33 of the station 32.

This latter alternative step would be performed after distributing the base mix M2 on the temporary support 2 and after removing the covering element 34.

Differently from the prior art and owing to the fact that distribution of the additional mix Ml is performed before distribution of the base mix M2, it should be noted that the covering element 34 does not have openings such that the U-shaped profiles 36 cover both the sides and the tops of the mounds C. The covering element 34 may also comprise a cage 52, which may be fixed to the support structure 38 of the covering element 34 - shown schematically in Figures 13-15 - and the function of which will be described below.

Said cage 52 is composed preferably of a series of transverse metal wires which are parallel to each other or by a series of interwoven wires.

The distribution means 16 of the first embodiment in the second station 8, as shown more clearly in Figures 7 and 13-16, are preferably formed by a skimming volumetric distributor 40 which passes lightly over the surface of the covering element 34 during the distribution of the base mix M2. The volumetric distributor 40 comprises:

- a hopper 42 with a shaped wall designed to be filled with a predetermined quantity of base mix M2;

- a container 44 - preferably cylindrical - designed to receive the predetermined quantity of base mix M2 from the hopper 42 so as to distribute it in the areas of the at least one temporary support 2 outside the mounds C of additional mix Ml;

- an extractor belt 50 located between the hopper 42 and the container 44 and intended to transport the base mix M2 from the hopper 42 to the container 44.

Said volumetric distributor 40 is designed to perform a relative translation movement with respect to the conveyor belt 12 of the second station 8 and the temporary support 2 which rests on the conveyor belt 12, in particular along a direction parallel to the direction of advancing movement of the at least one temporary support 2.

During this movement, the volumetric distributor 40 performs skimming of the mix at a height corresponding to approximately the height of the U-shaped profiles 36 of the covering element 34.

The relative translation movement may take place by means of displacement of the volumetric distributor 40 or by means of displacement of the temporary support 2.

The function of the cage 52 of the covering element 34 is to favour the uniform distribution of the base mix M2 inside the at least one temporary support 2, avoiding the formation of mounds of this mix during the advancing movement of the skimming volumetric distributor 40.

Advantageously the container 44 is provided with rotating blades 46 having a respective drive system 47 for favouring the discharging and distribution of the base mix M2 from a bottom opening 48 (see in particular Figures 14-16).

The skimming volumetric distributor 40 of the second station 8 is also provided with a closing cover 54 designed to selectively close the bottom opening 48 of the container 44.

Said cover 54 is intended to be engaged with a fixed portion of the second station 8 before the skimming volumetric distributor 40 starts to distribute the base mix M2 inside the temporary support 2 (see in particular the enlarged detail of Figure 14).

This arrangement enables the bottom opening 48 of the container 44 to be gradually freed by the cover 54 during the distribution of the base mix M2 so as to allow discharging of the base mix M2.

In this way, the bottom opening 48 is completely freed by the cover 54 only when the skimming volumetric distributor 40 is entirely positioned above the temporary support 2 (see in particular the enlarged detail of Figure 15).

The skimming volumetric distributor 40 may also perform a translational movement in the opposite direction during which it continues to distribute the base mix M2 so as to uniformly fill the at least one temporary support 2.

Then the cover 54, which has been previously engaged with the fixed portion of the second station 8, moves backwards and engages again with the container 44, closing again the bottom opening 48.

The means 16 for distributing the base mix M2 in the second embodiment shown in Figure 8 instead comprise:

- a hopper 42 designed to be filled with the base mix M2;

- a pair of walls 43 designed to delimit a space for collecting the base mix M2 supplied by the hopper 42, the walls 43 having scraping bottom ends 45;

- an extractor belt 50 situated between the hopper 42 and the collection space for transporting the base mix M2 from the hopper 42;

- a pair of rotating brushes 49 located in the vicinity of the walls 43 and on the outside of the collection space.

The bottom ends 45 of the walls 43 have skimming profiles, which may be shaped, for levelling off the base mix M2 distributed inside the at least one temporary support 2 during the relative movement of the distribution means 16 and the at least one temporary support 2.

The brushes 49 have transverse rotation axes parallel to the walls 43 and also allow levelling off the base mix M2 distributed inside the at least one temporary support 2 as well as having the function of removing any excess base mix M2 which has been deposited on the cover 32, pushing it into the free spaces.

In accordance with the present invention the apparatus 1 further comprises: - at least one forming element 104 for forming, in the base mix M2 inside the at least one temporary support 2, areas for the distribution of a liquid or powder dye D;

- a unit 106 for distributing the liquid or powder dye D in these areas of the base mix M2;

The at least one forming element 104 is shown in detail in Figures 5 and 6 and the at least one unit 106 for distributing the liquid or powder die D is visible, with reference to the apparatus 1, in Figures 1 and 3 and partially in Figures 2 and 4.

Preferably, the at least one forming element 104 is a cover or a covering element having a plurality of forming means 134 intended to penetrate into the base mix layer M2 distributed beforehand in the at least one temporary support 2 in order to form a plurality of grooves F after the forming element 104 has been removed.

The grooves F correspond to the areas intended for the distribution of the liquid or powder dye D. The layer of base mix M2 which is contained in the temporary support 2 and in which the grooves F are formed is shown in Figures 2 and 4.

Advantageously, and as shown more clearly for example in Figures 1, 3 and 6, the at least one forming element 104 is removably engaged with the at least one temporary support 2 and/ or is used in the second station 8 for distributing the base mix M2.

In a preferred embodiment of the invention, the forming element 104 coincides with the covering element 34 described above for the covering the mounds C of additional mix Ml with the addition of the forming means 134.

The forming means 134 consists preferably of blades or strips which have a preferably wedge-shaped cross-sectional form, the blades or strips 134 having a height which is the same as or smaller than the depth of the at least one temporary support 2, as shown in Figures 5 and 6 and in the enlarged details of Figures 7 and 8.

In this way, after the distribution of the liquid or powder dye D inside the grooves F, the inclusions and/ or the veining may occupy the entire thickness of the slab or only a part of the thickness of the slab. As shown more clearly in Figures 1 and 3, the unit 106 for distributing the liquid or powder dye D is located downstream of the station 8 for distributing the base mix M2 and comprises means for distributing the dye D.

As shown more clearly in Figures 1 and 2, the means for distributing the liquid or powder dye D of the first embodiment comprise a container 105 mounted on one end of a robotic arm 107 and having a hole for discharging the dye D.

The robotic arm 107 may also be replaced by container movement means of the Cartesian type, without thereby departing from the scope of protection of the present invention.

Alternatively, in accordance with the second embodiment of the means for distributing the dye D shown in Figures 3 and 4, said distribution means may comprise a bridge structure 109. Said bridge structure 109 is intended to distribute a stream of dye D onto the base mix M2; the dye D thus distributed is deposited partly inside the grooves F formed in the base mix M2 and partly on the surface of the base mix M2; this latter portion of the dye D may be subsequently removed by means of slab calibration and smoothing operations.

As mentioned above, the inclusions and/ or veining realized using the liquid or powder dye D have widths and thicknesses which are smaller than the widths and thicknesses of the inclusions and/or veining obtained by means of the additional mix Ml .

In particular, the inclusions and/or veining thus obtained have dimensional widths of between 3 and 10 mm and dimensional thicknesses of between 5 and 40 mm.

The apparatus 1 may also comprise a further station, not shown in the attached figures, located downstream of the second distribution station 8 and upstream of the compaction station of the plant.

This further station may comprise means for forming further veining in the base mix M2 having a width smaller than that of the veining beads C formed beforehand with the additional mix Ml.

Although at least one temporary support 2 has been mentioned in the above description, obviously the apparatus 1 according to the present invention may operate simultaneously on several temporary supports 2.

In this connection and as shown in Figures 1 and 3, while a temporary support 2 is located in the first station 6 for receiving the additional mix Ml, another temporary support 2 with the mounds C of additional mix Ml distributed beforehand may be located in the spraying station 32, a further temporary support 2 may be located in the second distribution station 8 for receiving the base mix M2 and optionally a further temporary support 2 may be positioned in the unit 6 for distributing the liquid or powder dye D after the grooves F have been formed in the base mix layer M2.

The first distribution station 6, the spraying station 32, the second distribution station 8, the unit 106 for distributing the liquid or powder dye D and the movement means 10 are connected to a control unit, not shown in the figures, for selective operation thereof.

The present invention also relates to a method for performing inclusions and/or veining in slabs manufactured from at least one base mix M2 and at least one additional mix Ml, the mixes Ml, M2 being able to undergo successively at least one compaction step and a hardening step for producing the slabs.

The method comprises preferably the following steps: a) providing at least one temporary support 2 having inside it at least one recess 9 and areas 11 outside the at least one recess 9, the at least one temporary support 2 being movable along a feeding direction by movement means 10; b) distributing at least one additional mix Ml inside the at least one recess 9 so as to form at least one mound C of additional mix M corresponding to at least one inclusion and/ or veining to be obtained in the slab; c) distributing at least one base mix M2 on the at least one temporary support 2 in the areas corresponding to the areas 11 outside the at least one recess 9.

The method may also comprise a step d) of forming a plurality of grooves F in the base mix M2 and a step e) of distributing a liquid or powder dye D inside the grooves F so as to form inclusions and/ or veins with widths and thicknesses smaller than the widths or thicknesses of the inclusions or veins obtained by means of the additional mix Ml.

As already mentioned above with reference to the apparatus 1, the at least one temporary support 2 has inside it a plurality recesses 9 and the additional mix Ml is distributed inside the recesses 9 so as to form a plurality of mounds C of additional mix Ml corresponding to a plurality of inclusions and/ or veins to be obtained in the slab.

Preferably, the inclusions in the slabs consist of veins formed in the slabs and the mounds C of additional mix Ml consist of veining beads; for this purpose, the recesses 9 of the temporary support 2 are formed by grooves 9 inside which the additional mix Ml is distributed in order to form the mounds C of additional mix Ml intended to form the veining beads and the inclusions and/or veining following the compaction step.

Preferably the method involves a step of positioning a filling template 4 on the at least one temporary support 2, the filling template 4 being of the type described above and comprising a frame 5 and a pair of shaped and adjacent profiles 7 which extend from the frame 5 in order to define and delimit the recesses or the grooves 9 described above.

Furthermore, the frame 5 and the pairs of profiles 7 define between them the areas 11 situated outside the profiles 7 and therefore outside the grooves 9.

The method also comprises a step of removing the filling template 4 from the at least one temporary support 2. The step of positioning and the step of removing the filling template 4 are performed respectively upstream and downstream of the step b) for distributing the at least one additional mix Ml. With reference to the apparatus 1 described above:

- the step of positioning and the step of removing the filling template 4 are performed by the positioning means present in the first station 6, the removal step being shown in detail in Figure 12;

- the step b) is performed by the distribution means 14 of the first station 6 described above and shown in detail in Figure 9;

- the step c) is performed by the distribution means 16 of the second station 8 described above, in particular by the skimming volumetric distributor 40, in accordance with both the first and the second embodiment; this step is shown in the detail of Figures 14 and 15.

A step involving pressing and partial compaction of the mounds C of additional mix Ml may be preferably performed upstream of the step for removal of the filling template 4.

Said pressing step, which is shown in the enlarged detail of Figure 11, is performed by means of the pressing cover 20 described above; said pressing cover 20 comprises projections 22 with a profile corresponding to and/or complementing and mirroring the at least one recess 9, namely the grooves 9, and designed to be inserted inside the at least one recess 9, or inside the grooves 9; the pressing step is shown in the detail of Figure 4.

The method may also comprise a step, performed downstream of the pressing step, of spraying one or more paints onto the sides of the mounds C. This spraying step is performed by means of the spraying station 32 of the apparatus 1 described above.

Furthermore, the method comprises a step of covering and protecting the mounds C of additional mix Ml distributed during step b), said covering step being performed downstream of the step for removal of the template 4 and upstream of the step c) for distribution of the base mix M2.

This step is performed by means of the covering element 34 of the second station 8 described above (see the enlarged detail of Figure 13).

Conveniently, the step d) is performed by means of the at least one forming element 104 described above and the step e) is performed by means of the at least one unit 106 for distributing the liquid or powder dye D described above with reference to the apparatus 1.

From the above description it is now clear how the method and the plant according to the present invention are able to achieve advantageously the predefined objects.

In particular, owing to the special features of depositing the additional mix before the base mix and pressing the mounds of additional mix before distributing the base mix, it is possible to obtain inclusions and veining in the slabs which have a greater width than the inclusions and the veining obtained with the methods known in the sector.

Furthermore, owing to the provision of the at least one forming element 104 and the at least one unit 106 for distributing the liquid or powder dye D, it is possible to obtain veining with smaller widths and thicknesses together with veining having larger widths and thicknesses.

The possibility of performing both so-called thin inclusions and/ or veining and so-called wide and thick inclusions and/ or veining does not increase the costs and the complexity of the apparatus according to the present invention.

As a result of these special features it is possible moreover to provide inclusions and veining which have well-defined and clearly marked edges inside the body of the slab, resulting in an aesthetic effect similar to that of natural stone.

Furthermore, the configuration described above allows simplification of the structure of the apparatus according to the present invention compared to the apparatus known in the sector, thereby limiting the costs for production thereof.

Obviously, the above description of embodiments applying the innovative principles of the present invention is provided by way of example of these innovative principles and must therefore not be regarded as limiting the scope of the rights claimed herein.