WO2006095249A2

WO2006095249A2 - Method and apparatus for transferring granular material to a mould

Info

Publication number: WO2006095249A2
Application number: PCT/IB2006/000506
Authority: WO
Inventors: Carlo Antonio Camorani
Original assignee: Mira Di Algeri Maris
Priority date: 2005-03-09
Filing date: 2006-03-09
Publication date: 2006-09-14
Also published as: ITRE20050023A1; WO2006095249A3

Abstract

The invention relates to a method and a corresponding apparatus for transferring granular material (5) to a mould for pressing (14) tiles, which provides for: - preparing on a surface (2) that is movable in an advancing direction (X) an aggregated layer (7) of granular material (5) of a width (Z) corresponding to the width of the tile; cutting the most advanced portion (P) of said aggregated layer (7) to a length (L) corresponding to the length of said tile; - distancing said portion (P) from said surface (2) keeping said portion (P) raised with vacuum means (11) and without substantial formation of scraps of said granular material (5) .

Description

MQVMENT QF GRANULAR MATERIAL

The invention relates to methods and apparatuses for transferring granular material, advisable for supplying pressing moulds in the manufacture of tiles or objects with a non-uniform thickness.

A known system for supplying moulds discloses preparing on a belt the layer of granular material, removing this layer with a box open below, keeping the layer raised through the effect of a vacuum, moving the box with the contents above the mould recess and transferring the layer through exclusion of the vacuum. Some versions and improvements of this system are disclosed in US4306595, EP0860256, EP0997248 and EP1447190. EP0997248 discloses positioning of a layer with low permeability at the base of the loose material to be transferred so as to make the vacuum effect effective and enable very stable and complete lifting.

EP1447190 discloses making the layer of powders to be transferred slightly coherent, selecting a portion thereof inside a frame and transferring it to the mould by means of the vacuum box with permeable baffle. The portion of powder outside the frame • constitutes a scrap that, after possible crushing, can be recycled. Adopting this vacuum technology with respect to other traditional systems offers significant advantages of speed, simplification, versatility and filling of the mould recess without decomposition of the load, but it can nevertheless be improved to overcome certain drawbacks that may arise from using particular granular materials and to achieve further advantages.

A drawback is the generation of the scraps of granular material . It is admittedly true that they can be recycled directly in the productive cycle, but in certain cases the moving of these scraps may be problematic, as for example may occur with a material of the type disclosed in WO2004/039564, in which the progressive solidification of a liquid resin, mixed with the granular material with a binding function, may cause clogging of the scraps conveying means .

A further drawback is the progressive clogging to which the permeable baffle of the vacuum box may be subject. This may occur especially when the granular material is sticky, of the type disclosed for example in the already disclosed WO2004/039564. In this case, in fact, the permeable baffle consisting of a fine mesh or a porous slab is subject to progressive clogging, which may force the productive cycle to be interrupted to restore normal operating conditions . EP0860256 discloses preparing the layer of loose material on a permeable surface and removing it with a suction box provided with a protruding peripheral frame; in this case, as the surface of the layer of loose material is arranged peripherally according to a slope that is very divergent from the vertical, to raise the entire layer without scraps of material remaining on the surface, the frame of the box has to be aligned beyond^' the external limit of the slope, but this entails and unacceptable shortage of material near the frame.

A version proposed in EP0860256, that should not lead to the production of scraps discloses preparing tiles that have already been preformed inside cavities obtained in the preparation surface and removing them with the suction box. This version nevertheless has more than a few implementation difficulties: firstly, it involves significant constructional and operational complications through the presence of the cavities. This version also has significant operating difficulties in the filling of the cavities and pressing the powders, also because perfect centring and synchronisation between the cavities and the filling means and pressing means are necessary. In addition, this version does not permit controlled insertion of the powders inside the cavities, especially near the edges, owing to the fact that the powders have to fall to the bottom of the cavity and cannot on the other hand be accompanied without decomposition. The versions also does not allow continuous compacting means to be used, such as rollers or rotating belts. In addition, for size changing replacing heavy machine parts and considerable manual labour are required. In this version, it is also difficult if not impossible to extract tiles from the cavity. A further version of EP0860256 involves extracting the tile by penetrating inside the cavity with the frame of the box. In this solution the frame is very vulnerable because of necessity it has to have a section of minimal thickness. Perfect centring in every direction between cavity and frame is also important as the smallest centring error leads to the frame itself being damaged, which further aggravates constructional and operating problems .

In EP0997248, uniform filling up to the proximity of the frame is obtained by operating with the frame in a position further inside the layer where the slope is not present, but here a certain amount of ^' granular material scraps remain on the preparing surface.

A version of EP0997248, in order not to generate scraps, adopts a preparing belt with transverse containing dividers, but also in this case the difficulties are present that were already listed with regard to EP0860256. The solution illustrated in EP1447190, which was already analysed before, implies the production of scraps. A further drawback present in the prior art is the difficulty of loading moulds for complex shapes, in particular when it is requested to fill the mould recess with a thickness that differs from zone to zone to adapt to a thickness of the pressed object that is not uniform.

Patent JP6206210 constructs the bottom of the mould subdivided into different portions with independent vertical mobility so as to position each portion at a different level during the filling and pressing phases, in order to keep the ration between the thickness of soft material and the thickness of pressed material uniform. Such a solution implies significant constructional and operational complexity, especially if the thickness of the object to be pressed is more complicated.

EP1354679 proposes varying the thickness of the soft material during the levelling phase through scraping using a scraper provided with a variable profile that is controlled by computer. Also this solution is very complicated and is difficult to apply in certain cases. A first object of the present invention is to enable the mould to be supplied with support and transfer of the granular material from above by means of a vacuum, without generating scraps of granular material and keeping the system simple and functional.

A second object is to enable the mould to be supplied with support and transfer of the granular material from above through a vacuum, without problems of clogging or soiling in the vacuum apparatus even if sticky granular material is treated.

A third object is to enable a mould to be supplied with granular material arranged in a layer with a thickness that is locally varied in a controlled manner, keeping the system simple and functional.

A fourth object is to enable a mould for complex shapes to be filled correctly.

Some of these objects- are obtained in a first aspect of the invention by means of a method for transferring granular material to a mould for pressing tiles, comprising preparing on a surface that is movable in an advancing direction an aggregated layer of said granular material of a width corresponding to the width of the tile, cutting the most advanced portion of said aggregated layer of a length ■ corresponding to the length of said tile, distancing said portion from said surface keeping said portion raised with vacuum means and without substantial formation of scraps of said granular material.

In a second aspect of the invention an apparatus is provided for transferring granular material to a mould for pressing tiles, comprising a surface that is movable in an advancing direction, preparation means suitable for preparing on said surface an aggregated layer of said granular material of a width corresponding to the width of the tile, separating means suitable for cutting the most advanced portion of said aggregated layer of a length corresponding to the length of said tile, vacuum means that is movable from a position above said movable surface to a position above the recess of said mould and suitable for keeping said portion raised for transferring it to said recess.

In a third aspect of the invention an apparatus is provided suitable for transferring granular material to a mould for pressing tiles, comprising a surface that is movable in an advancing direction, preparation means suitable for preparing on said movable surface an aggregated layer of said granular material, vacuum means that is movable from a position above said movable surface to a remote position and is suitable for keeping said aggregated layer raised through the effect of a vacuum, characterised in that it comprises a wall provided with openings through which said vacuum is exerted, said openings being of a dimension that is noticeably greater than the dimension of the granules constituting said granular material so that said granules cannot remain trapped in said openings .

In a fourth aspect of the invention a method is provided for transferring granular material to a mould for pressing tiles, that comprises preparing on a surface that is movable in an advancing direction a layer of said granular material, acting with a vacuum through a wall for raising said layer from said surface, characterised in that it furthermore comprises widening openings in said wall so that said openings cannot remain obstructed by particles of said granular material and aggregating said granular material so that it cannot flow away through said openings that have been thus widened.

In un fifth aspect of the invention a method is provided for transferring granular material to a pressing mould that comprises preparing a layer of said granular material on a surface that is movable in an advancing direction coplanar with said surface, filling with said layer a recess above said surface, acting with vacuum means for keeping said layer raised in said recess and transferring them together, characterised in that said filling occurs through an approach movement between said layer and said recess in a direction parallel to said advancing direction.

In a sixth aspect of the invention an apparatus is provided for transferring granular material to a pressing mould comprising, a surface that is movable in an advancing direction, preparation means suitable for preparing on said movable surface a layer of said granular material, a transferring means provided with a recess open below cooperating with vacuum means suitable for keeping said granular material raised and transferring it to said mould, characterised in that said recess has an access opening for said layer on the side upstream of said advancing direction. The invention can be better understood with the help of the attached tables that show some embodiments thereof by way of non-limitative example, in which: Figure 1 is a perspective view of an apparatus according to the first, second, third and fourth aspect of the invention; Figures 2 to 6 are schematic side views showing the apparatus in Figure 1 in different operating phases; Figure 7 is a schematic side and section view of a detail of Figure 1 showing the vacuum means; Figure 8 is a perspective and partial view of the vacuum means in Figure 7 according to the invention; Figures 9 and 10 are perspective views like those in Figure 8 showing two further versions of the invention. Figure 11 is a schematic side view of an apparatus according to the fifth and sixth aspect of the invention; Figures 12 a 14 are views like those in Figure 11 showing different operating phases;

Figure 15 is a schematic and partial side view of the apparatus in Figure 11 in a mould-filling operating phase; Figure 16 is a schematic side view of the mould in Figure 15 in the pressing phase;

Figures 17 to 20 are schematic side views of a version of the apparatus according to the fifth and sixth aspect of the invention, showing different operating phases; Figure 21 is a section view XXI-XXI of Figure 18;

Figures 22, 23 and 24 are plan views of three further versions according to the fifth and sixth aspect of the invention.

The apparatus 1 comprises a belt 2 wound on rollers 3, that is movable in an advancing direction X, on the surface of which a layer 4 of granular material 5 is arranged through distributing means that is not shown. Granular material is defined as a loose material consisting of granules of any dimension or shape, powders, flakes, fibres, granules of various colours with surface or integral colours, recovered material, etc., in any combination, not limited to ceramic use. This loose material may possibly be mixed with substances in liquid or semi-plastic state intended to constitute, after suitable treatment, the binding of a finished tile or a temporary binder. A compacting station 6 is present acting on this layer 4

' so as to level it and transform it into an aggregated layer 7. In the case in point this station 6 consists of a rotating roller 8 but can consist of any other known device that is suitable for the object. There is lateral moulding means 9 that is suitable for defining the width

Z of the aggregated layer having a measure exactly equal to the width of the tile and has a peripheral margin 10 arranged according to substantially vertical walls. The term "aggregate" is defined as a state of cohesion between the various particles of granular material 5 that is at least such as to enable the layer 7, when subject to the force of gravity without lateral containing, to substantially maintain a temporary vertical-wall shape. A aggregation of this amount is easily obtainable with modest pressure, thus not involving the use of expensive machinery.

Above the_. end part of the belt 2 there is a box vacuum device 11, that is open below and is laterally delimited by a frame 12 protruding downwards . This end part of the belt 2 is movable vertically for a certain portion in a direction Y so that the surface thereof can approach the frame 12, contacting it or at a position very close thereto. The side 13 of the frame 12 facing further upstream with respect to the advancing direction X is shaped like a cutting blade so as to be able to easily penetrate the aggregated layer 7 without decomposing it. The vacuum box 11 is movable from a position above the end part of the belt 2 to a position above the pressing recess of a mould 14.

Inside this movable box 11 a permeable wall 15 is defined that is intended to constitute the support for the aggregated layer 7. Above the wall 15 there is a chamber 16 that is connected by means of the manifold 17 to suction means that is not shown. The operation of the apparatus is as follows :

- the plane of the belt 2 is in the lowered position, the movable box 8 is in the inside part of the frame 12 thereof perfectly colimated with the lateral 10 and the frontal 18 peripheral margin;

- the plane of the belt 2 rises in the direction Y and a portion P of layer 7 of a length L corresponding to the length of the tile is thus cut by the side 13 of the frame and the inside of the box 11 is thus filled by the portion P of layer 7 (Figure 3) ;

-through the manifold 17 a vacuum is activated and the belt 2 is made to advance in the direction X in synchronism with the advance of the box 11; -as' shown in Figure 4, whilst the box 11 protrudes beyond the limit of the belt 2, the portion P of layer 7 is kept raised by the atmospheric pressure Q and is taken to a position above the pressing recess, where, through exclusion of the vacuum, it is inserted by gravity (Figure 5) ; -during the preceding phase, when the box 11 has completely passed the limit of the belt 2, the plane of the 2 descends to the start position (Figure 5) thus enabling the return of the box 11 to the initial position (Figure 6) without obstacles. It is to point out that moving the belt 2 vertically is very advantageous in certain circumstances with respect to the known alternative that instead provides for moving the box 11 vertically: in fact, in the latter case, during the return, the box 11 could interfere with the layer 7 already positioned at the end of the belt 2, and, to avoid that, a space should be left between the mould 14 and the end of the belt 2 that is at least equal to the length dimension of the box 11, or, alternatively, the box 11 should be raised whilst it is still inside the mould 14. However, this is not always possible because of the structural limits in the opening of the press, and it would anyway cause prolongation of the pressing cycle due to the longer horizontal path of the box 11 or longer vertical path of the mould 14. It is to point out that the invention enables the portion P of layer 7 to be sized and centred exactly, concentrating only on the alignment of the frontal margin 18 with respect to the front frame 12. An important aspect of the invention is furthermore to be pointed out consisting in that during cutting of the portion P of layer 7 automatically and without generation of scraps also the precursor of a new frontal margin 18a that is already shaped as a vertical wall is obtained; this enables the awkward transverse containing walls to be eliminated that are always present in the state of the art when generating scraps of material is not desired.

The invention thus enables decorating means or any other preparing means .of the powders for decorative or functional purposes operating in a position very near the surface 2 to be used, there being no transverse walls or containing cavities that may interfere during advancing of the surface 2. The apparatus is thus simple and versatile also during size change. In the illustrated example the surface 2 is smooth and impermeable, but a permeable surface 2 can nevertheless be used: this enables the box 11 to be immediately spaced apart from the surface 2 in a vertical direction without waiting for complete passing of the limit of the belt 2 by the box 11. In this way it is also possible to provide the surface 2 with continuous movement in direction X without interruptions, dynamically cutting

(synchronously) the portion P of layer 7 and filling the box 11. Using the surface 2 without permeability may be useful, for example if the treated material contains fluid binders, of the fluids resins type, which could hamper the permeability of the belt 2. The illustrated apparatus may also operate in the following different manner: the box 11, as soon as it has been filled as it appears in Figure 3, can start in the direction X to the mould 14 at a speed that is greater than the speed of the belt 2 remaining adhering to it and sliding over it in contact. Thus also in this case (but regardless of whether the type of surface 2 is permeable or impermeable) , the surface 2 can be provided with constant movement in the direction X without interruptions, cutting the portion P and filling the box 11 synchronously. The latter disclosed version, may in certain cases encounter operating difficulties because the belt 2, especially if it is not permeable, tends to adhere to the box 11, opposing sliding. As illustrated in Figure 7 the wall 15 of the box 11 has openings 19 the dimension D of which is noticeably greater than the dimension of the granules G. This conformation resolves the problem of clogging of the wall 15 as the granules of material cannot remain trapped in narrow slits.

The possibility of using this system is subordinated to the fact that the layer 7 has to have a certain degree of aggregation between the various particles. With a thick layer 7 with high aggregation the openings 19 may be of a great dimension D, in the case of low aggregation the dimension D of the openings 19 will have to be more limited so that the layer 7 does not undergo noticeable deformation or disintegration at the openings 19. Minimal optimal aggregation could be what enables the layer 7 to remain undamaged, without noticeable flaking or deformation, when resting on supports 20-30 mm apart in the presence of ^' gravity. This is thus easily obtainable aggregation that is obtainable with simple means and which can ensure good operation also with openings D of 30-40 mm. It should be remembered that the vacuum to be applied to the chamber 16 will be what is sufficient to overcome the force of gravity and keep the layer 7 raised with a certain safety margin, so the force exerted by the layer 7 against the wall 15 may also be much less than the force of gravity.

Advantageously the D/G ratio is greater than 10. Advantageously, the dimension D of the openings 19 is greater _. than the thickness S of the layer 7 or, alternatively, of a dimension comprised between 5 mm and 50 mm.

Possible slight plastic deformations of the layer 7 at the openings 19 can be tolerated because they will disappear during final pressing. As shown in Figures 7 to 10, the dimension D of the openings 19 is defined as the dimension measured in a portion of maximum proximity between opposite borders of the opening 19. Advantageously, the wall 15 and the edge of the openings 19 have non-stick features, such as for example can be obtained with a polytetrafluorethylene (Teflon^®) coating. The same non-stick treatment is also advantageously applied to the frame 12, 13. The presence of adhesive liquid substances, which would cause rapid clogging of a traditional permeable baffle (also accentuated by a capillary effect) , cannot in this case cause any disturbance because the openings 19 will any way remain functional and "self-cleaning". Possible residual granules present on the surface 15, or on the frame 12, 13, will be automatically detached in the subsequent cycles as they will be more subject to adhering to the aggregated layer 7 than to the non-stick surfaces . As shown in the example in Figure 9 from the bottom wall 20 of the chamber 16 cylindrical spacing elements 21 emerge. In this case the wall 15 is configured . at the top 22 of these cylindrical elements 21, arranged separated from one another in a plan view, whilst the openings 19 are intercommunicating and defined in the entire free space around said cylindrical elements 21. In an embodiment that is not shown cylindrical elements 21 are an integral part of the bottom wall 22 being obtained by deforming the wall 20 through drawing or moulding. Furthermore, this wall 20 can be of plastics formed through moulding and with spacing elements of any other shape. In the example in Figure 10 the wall 15 is defined by rollers 23 arranged parallel to the plane of the layer 7. These rollers 23 can be rotatable around the axis thereof to be rotated occasionally in contact with scraping means suitable for performing the cleaning thereof . The internal wall of the frame 12, 13 has advantageously a certain tilt diverging downwards, this permits facilitated insertion of the layer 7 and furthermore ensures better contact of the peripheral margin 10, 18 against the high part of the frame 12, 13, so as to form a seal and to make the vacuum effect more effective.

An important aspect of the vacuum device 11 according to the invention should be highlighted, . namely that the openings 19 do not act as if each one of them were a distinct "suction cup". In the case of distinct suction cups the effect of the vacuum would be limited only to the area covered by each suction cup and it would also be a minor effect, the layer P being very permeable, there would be great introduction of air from the upper zones of the layer P surrounding the suction cup.

In the case of. the invention, the vacuum device 6 acts as a single big suction cup in which the seal is exerted peripherally (mainly by the side walls 12, 13) , from the upper zones of the layer P no entry of air is thus possible and the atmospheric pressure Q acts on the lower face of the layer P 'in a substantially uniform and effective manner over the whole area.

Modifications of a practical applicational nature can be made to the invention.

Thus a plurality of layers 7 can thus be transferred that are longitudinally parallel and are arranged on the same surface 2 or on distinct surfaces 2.

The advancing direction X of the surface 2 can be orthogonal to the advancing direction of the box 11 to the mould 14. The lateral moulding means 9 can be of the rotating type.

Instead of the rollers 23 fixed slats can be used. Decorative materials can be applied to the layer 4 of granular material 5, before and/or after the compacting station 6.

With reference to the Figures 11 to 20 the apparatus 51 comprises a permeable belt 52 wound on rollers 53, that is movable in an advancing direction X and^' on the surface of which a layer 54 of granular material 55 is arranged through distributing means that is not shown.

Above the end part of the belt 52 there is a box device

56, that is movable from a position above the surface 52

(Figures 11-13) to a position above a pressing mould 57

(Figure 15) . The box device 56 is open below and is delimited peripherally by a frame protruding downwards, the frame has lateral walls 58 arranged parallel to the advancing direction X, a blocking wall F arranged downstream with respect to the advancing direction X and a movable wall 59 arranged further upstream with respect to the advancing direction X, this movable wall 59 is shaped as a cutting blade so as to penetrate the layer 54 without difficulty and is movable vertically in a direction W from a raised opening position (Figures 11-12) to a lowered closed position (Figures 14-15) .

Inside the box 56 there is a permeable baffle 60 that together with the frame 58, 59, F defines the room 61 intended to be filled with granular material 54. Above the permeable baffle 60 there is a chamber 62 connected to suction means that is not shown. The surface of the permeable baffle 60 facing downwards has indentations 63 and protrusions 64 that are suitably arranged and sized in relation to the various thicknesses S3, S4 of the object to be pressed 65. These protrusions can also be constituted by bodies that are distinct from the permeable baffle 60 and are anchored to it by removable fixing systems (for example Velcro^®) . These bodies do not necessarily have to be permeable, because if they do not have a great extent, the vacuum will anyway have the possibility of acting in a sufficient manner. This possibly enables the depth of the room 61 to be varied in an easy and controlled manner without costly interventions .

As shown in Figure 11 in the initial phase of the cycle the box 56 is arranged with the frame 58, F in sliding contact on the surface 52 whilst the frame 58, 59, F is raised, thus leaving the room 61 open. The surface 52 advances in the direction X and the layer 54, being slightly less thick than the height of the room 61, can also advance without obstacles. When the front B of the layer 54 meets the blocking wall F (in a blocking position R) the granular material 55 starts to accumulate, expands and progressively fills each empty space of the room 61 (Figure 12) . ■ When the room 61 has been completely filled the wall 59 descends, isolating inside the room 61 the portion of granular material 55 to be transferred (Figure 13) . A this point a vacuum is activated in the chamber 52 and the box 56, together with the granular material 55 contained therein is moved above the cavity of the mould 57 (Figure 15) where, through exclusion of the vacuum, the granular material 55 descends, keeping substantially the same thicknesses Sl, S2 acquired inside the room 61. The various thicknesses of soft material Sl, S2 are defined in such a way that the ratio between the soft thickness Sl, S2 and the thickness of pressed material S3, S4 is substantially constant in each zone, in order to ensure maximum pressing uniformity. In other words, the equation Sl/S3=S2/S4 will be maintained. The mould 57 has a lateral containing matrix M, a lower buffer T and an upper punch N. The layer 54 arranged on the surface 52 is laterally contained by longitudinal walls (not shown) that extend up to the mouth of the room 61, said walls being spaced apart form one another by a dimension that is the same as the width dimension of the room 61 (and corresponding to the width dimension of the object 65 to be pressed) . In this way uniform filling of the. room 61 is ensured, up to the proximity of the side frame 58- without leaving scraps of granular material 55 on the surface 52. In a version illustrated in Figures 17 to 21, the layer 54 of granular material 55 is freely arranged on the surface 52 without the help of longitudinal containing walls and according to a width Zl between the most external positions of the slopes 67 that is the same as or slightly less than the distance V between the lateral walls 58 of the room 61. In this version the surface 52 can advance in a continuous manner and positioning of the box 56 on the surface 52 can occur when the front B of the layer 54 has already gone past the position C, where closing of the room 61 will occur, and will already be very near the position R where blockage of the layer 54 will occur.

In this version the pressing cycle is much abbreviated as the box 56 does not have to be positioned beforehand and passively wait for the surface 52 to travel along the portion that is equivalent to the length of the room 61, and can be further shortened by moving the box 56 during the filling phase in a direction X2 that is opposite the advancing direction X of the surface 52, filling thus occurs in "dynamic" mode. Furthermore, in this version wear is lessened as the time and spaces of sliding in , contact between frame and surface 52 are reduced.

As shown in Figure 21, in order to compensate for a possible shortage of material (due to less density) near the lateral walls 58, the room 61 will be advantageously sized with a greater thickness near the lateral walls 58 providing the permeable baffle 60 with suitable longitudinal recesses 68. Furthermore, to compensate for the lack of material caused by the presence of slopes 67, the layer 54 will be shaped with an enlarged thickness H along the two marginal strips adjacent to the slopes 67. The ends of the lateral walls 58 and of the blocking wall F of the room 61 intended for contact against the movable surface 52 will be advantageously provided with suitable seal washers U suitable for containing the granular material 55 and withstanding abrasion.

In the version shown in Figure 22', the two lateral . walls 58 of the box 56 protrude upstream to the outside of the room 61, slightly diverging like conveying walls 69 and in contact on the surface 52. The layer 54 • is freely arranged on the surface 52 at a width Zl that is slightly in excess of the width dimension V of the room 61, during the cycle, during the step of reciprocal approach between the layer 54 and the room 61, the excess part of the layer 54 is deviated by these conveying walls 69 to the inside of the room 61. Better filling of the gap 61 is thus obtained near the lateral walls 58 without leaving scraps of material on the surface 52 and without there being lateral containing walls on the surface 52.

In the version in Figure 23 there are lateral containing walls 70 of the layer 54 extending beyond the limit downstream of the surface 52. The lateral walls 58 of the device 6, suitably sized with a thin section, can slide longitudinally very close to or in direct contact with the walls 70, filling of the room 61 in dynamic mode is thus permitted without substantial decomposition of the layer 54 even near the lateral walls 58 and without generation of scraps . In the version in Figure 24 the lateral containing walls 70 end against the mouth of the opening of the room 61 and are longitudinally movable for following the movement X2 of the movable box 56 during dynamic filling. The invention can also find practical application in the production of ceramic tiles decorated in depth or superficially, as in filling the box 56 a possible pattern in the layer 54 will be subject only to slight reducing deformation along the advancing direction X. Possible visible surface granules of decorative material present in the layer 54 will any way remain in a surface and visible position even after the transfer to the mould 57.

In order to make the effect of the vacuum effective and to enable a really stable and complete lifting, it is advantageous to position at the base of the layer 54 a thin layer of finer and more compacted granular material or, in any case, a layer with low permeability as provided for by EP0997248. In the example illustrated in Figures 11 to 14 the surface of the belt 52 is permeable, but a smooth and impermeable surface 52 can be adopted. In this case the distancing of the box 56 from the surface 52 will be obtained by moving it in the advancing direction Xl at a synchronous speed with respect to the speed of the surface 52, or at a speed X3 that is greater with respect to the speed Xl of the surface 52, making the layer 54 slide on the surface 52, as shown in Figure 60. By so doing, the atmospheric pressure Q will act on the granular^' material 55 as the latter comes to protrude beyond the limit of the belt 52. The invention enables decorating means or any powder decorating means to be used for decorating or functional purposes also operating in a position very near the surface 52, there being no transverse cavity or containing walls that may interfere during advancing of the surface 52. The apparatus according to the invention is simple and versatile also in size changing. It is pointed out that the invention, in conformity to one of the intended objects, enables the thickness of the soft material to be transferred to a mould to be determined in a simple, precise and constant manner.

The invention also enables moulds for complex shapes to be filled where mould parts protruding excessively would not enable the layer to be levelled- by scraping. Modifications of a practical applicational nature can be made to the_. invention: thus for example also the embodiments illustrated in Figures 17 to 24 may have a permeable belt 52 surface, in this case the distancing of the box 56 from the surface 52 will occur by first distancing it vertically, as illustrated in Figure 14. The invention is particularly indicated for producing ceramic tiles but can also find practical application in the manufacture of crockery, ceramic or cement roof tiles, plates- or objects constructed with: recovered materials, metal powders to be sintered-, plastics, and not necessarily for filling a mould gap directly.

Claims

1. Method for transferring granular material (5) to a mould for pressing (14) tiles, comprising preparing on a surface (2) that is movable in an advancing direction (X) an aggregated layer (7) of said granular material (5) of a width (Z) corresponding to the width of the tile, cutting the most advanced portion (P) of said aggregated layer (7) of a length (L) corresponding to the length of said tile, distancing said portion (P) from said surface (2) keeping said portion (P) raised with vacuum means (11) and without substantial formation of scraps of said granular material (5) .

2. Method according to the preceding claim, wherein said preparing comprises shaping along a substantially vertical plane the frontal limit (18, 18a) of said aggregated layer (7) , said frontal limit (18, 18a) remaining thus shaped without the help of containing borders .

3. Method according to any preceding claim, wherein said preparing comprises shaping along substantially vertical planes the lateral limits (10) of said aggregated layer (7) , said lateral limits (10) remaining thus shaped without the help of containing borders .

4. Method according to any preceding claim, wherein said cutting arises from moving in a direction (Y) of reciprocal approach said movable surface (2) and a cutting side (13) of a frame (12, 13) of said vacuum means (11) .

5. Method according to the preceding claim, wherein said moving comprises moving upwards the plane of said movable surface (2) in a vertical direction (Y) .

6. Method according to claim 4, or 5, wherein from said moving there furthermore arises ^* shaping according to a substantially vertical plane the precursor of a new frontal limit (18a) of said aggregated layer (7) , said new frontal limit (18a) remaining thus shaped without the help of containing borders.

7. Method according to claim 6, wherein said precursor of a new frontal limit (18a) is arranged at a minimum distance from said portion (P) so as not to require elimination of granular material from said continuous aggregated layer (7) .

8. Method according to any preceding claim, which furthermore comprises at each transfer cycle advancing the said movable surface (2) in said advancing direction (X) by a dimension (L) substantially corresponding to the length of said tile.

9. Method according to any one of claims 6 to 8, wherein said precursor of a new frontal limit (18a) is arranged, with regard to said frontal limit (18) , at a distance (L) substantially corresponding to the length of said tile.

10. Method according to any preceding claim, wherein said preparing comprises tamping said granular material (5) .

11. Method according to any preceding claim, wherein said distancing comprises vertically spacing said portion (P) from said surface (2) .

12. Method according to any one of claims 1 to 10, wherein said distancing comprises horizontally moving said portion (P) beyond the horizontal limit of said surface (2) without vertically spacing said portion (P) from said surface (2) .

13. Method according to any preceding claim, wherein said spacing occurs by moving with synchronism in said advancing direction (X) said surface (2) and said vacuum means (11) .

14. Method according to any preceding claim, wherein said spacing occurs by moving said vacuum means (11) in said advancing direction (X) at a speed that is greater than the speed of the said surface (2) .

15. Method according to any preceding claim, wherein said preparing comprises preparing a plurality of said aggregated layers (7) placed alongside parallel in said advancing direction (X) .

16. Method according to any preceding claim, wherein said distancing comprises keeping said portion (P) raised by means of a permeable wall (15, 22, 23) of said vacuum means (11) provided with openings (19) of a dimension (D) that is noticeably greater than the dimension (G) of the granules constituting said granular material (5) so that said granules cannot remain trapped in said openings (19) .

17. Method according to any preceding claim, wherein said preparing comprises mixing said granular material (5) with substances in liquid or semi-plastic state intended to constitute, following treatment, the binder of the finished tile.

18. Method, according to any preceding claim, which is applied to the production of ceramic tiles.

19. Apparatus (1) for transferring granular material (5) to a mould (14) for pressing tiles, comprising a surface (2) that is movable in an advancing direction (X) , preparation means

(6, 8, 9) suitable for preparing on said surface (2) an aggregated layer (7) of said granular material (5) of a width (Z) corresponding to the width of the tile, separating means (13) suitable for cutting the most advanced portion

(P) of said aggregated layer (7) of a length (L) corresponding to the length of said tile, vacuum means (11,

16, 17) that is movable from a position above said movable surface (2) to a position above the recess of said mould (14) and suitable for keeping said portion (P) raised for transferring it to said gap.

20. Apparatus according to claim 19 wherein said preparation means comprises first moulding means (6, 8, 9) suitable for stably shaping along a substantially vertical plane the lateral limits (10) of said aggregated layer (7) .

21. Apparatus according to any one of claims 19 or 20, wherein said preparation means comprises second moulding means (13) suitable for stably shaping according to substantially vertical planes the frontal limit (18, 18a) of said aggregated layer.

22. Apparatus according to claim 21, wherein said second moulding means (13) and said separating means are integrated into a cutting-blade device (13) .

23. Apparatus according to claim 22, wherein said cutting-blade device (13) is comprised in a frame (12,. 13) of said vacuum means (11) .

24. Apparatus according to claim 23, wherein said frame (12, 13) has vertical external walls and divergent internal walls spreading out towards the bottom.

25. Apparatus according to any one of claims 19 to 24, wherein said preparation means comprises pressing means (8) suitable for aggregating said granular material (5) .

26. Apparatus according to any one of claims 19 to 25, wherein said surface (2) cooperates with moving means suitable for moving it in a vertical direction (Y) .

27. Apparatus according to any one of claims 19 to 26, wherein said surface (2) is the surface of an impermeable belt.

28. Apparatus according to any one of claims 19 to 26, wherein said surface (2) is the surface of a permeable belt.

29. Apparatus according to any one of claims 19 to 28, wherein said vacuum means (11, 16, 17) comprises a wall (15) provided with openings (19) through which said vacuum means (16, 17) acts, said openings (19) being of a dimension (D) that is noticeably greater than the dimension (G) of the granules constituting said granular material (5) so that said granules cannot remain trapped in said openings (19) .

30. Apparatus (1) according to claim 29, wherein the ratio between the dimension (D) of said openings (19) and the dimension (G) of said granules is greater than 10.

31. Apparatus (1) according to any one of claims 29, or 30, wherein the dimension (D) of said openings (19) is comprised between 5 and 50 mm.

32. Apparatus (1) according to any one of claims 29 to 31, wherein said wall (15) is of non-stick material.

33. Apparatus (1) according to claim 32, wherein said non-stick material comprises polytetrafluorethylene .

34. Apparatus (1) according to any one of claims 29 to 33, wherein said wall (15) consists of a slab with said openings

(19) passing through the thickness.

35. Apparatus (1) according to any one of claims 29 to 33, wherein said wall (15) is configured by the top (22) of spacing elements (21) arranged separated from one another in a plan view, said openings (19) being intercommunicating and defined in the entire free space around said spacing elements (21) .

36. Apparatus (1) according to claim 35, wherein said spacing elements (21) are protrusions of a moulded slab.

37. Apparatus (1) according to any one of claims 29 to 36, wherein said wall (15) is configured by a series of longitudinal elements (23) arranged parallel to the plane of said layer (7) .

38. Apparatus (1) according to preceding claim, wherein said longitudinal elements are rollers (23) rotating around the axis thereof .

39. Apparatus (1) according to preceding claim, wherein said rollers (23) cooperate with cleaning means.

40. Apparatus (1) according to any one of claims 19 to 39, wherein said wall (15) is surrounded by a frame (12, 13) protruding downwards.

41. Apparatus (1) according to any one of claims 29 to 40, wherein said tiles are ceramic tiles.

42. Apparatus (1) suitable for transferring granular material

(5) to a mould (14) for pressing tiles, comprising a surface (2) movable in an advancing direction (X) , preparation means (6, 8, 9) suitable for preparing on said movable surface (2) an aggregated layer (7) of said granular material (5) , vacuum means (11) that is movable from a position above said movable surface (2) to a remote position and is suitable for keeping said aggregated layer (7) raised through the effect of a vacuum, characterised in that it comprises a wall (15) provided with openings (19) through which said vacuum is exerted, said openings (19) being of a dimension (D) that is noticeably greater than the dimension (G) of the granules constituting said granular material (5) so that said granules cannot remain trapped in said openings (19) .

43. Apparatus (1) according to preceding claim, wherein the ratio between the dimension (D) of said openings (19) and the dimension (G) of said granules is greater than 10.

44. Apparatus (1) according to any one of claims 42, or 43 wherein the dimension (D) of said openings (19) is comprised between 5 and 50 mm.

45. Apparatus (1) according to any one of claims 42 to 44, wherein said wall (15) is of non-stick material.

46. Apparatus (1) according to preceding claim, wherein said non-stick material comprises polytetrafluorethylene .

47. Apparatus (1) according to any one of claims 42 to 46, wherein said wall (15) consists of a slab with said openings

(19) passing through the thickness and isolated from one another.

48. Apparatus (1) according to any one of claims 42 to 47, wherein said wall (15) is configured by the top (22) of spacing elements (21) arranged separated from one another in a plan view, said openings (19) being intercommunicating and defined in the entire free space around said spacing elements (21) .

49. Apparatus (1) according to preceding claim, wherein said spacing elements (21) are protrusions of a moulded slab.

50. Apparatus (1) according to any one of claims 42 to 49, wherein said wall (15) is configured by a series of longitudinal elements (23) arranged parallel to the plane of said layer (7) .

51. Apparatus (1) according to preceding claim, wherein said longitudinal elements are rollers (23) rotating around the axis thereof .

52. Apparatus (1) according to preceding claim, wherein said rollers (23) cooperate with cleaning means.

53. Apparatus (1) according to any one of claims 42 to 52, wherein said wall (15) is surrounded by a frame (12, 13) protruding downwards.

54. Apparatus (1) according to any one of claims 42 to 53 wherein said wall (15) delimits a chamber (-16) in which said vacuum is exerted.

55. Apparatus (1) according to preceding claim, wherein said chamber (16) extends in a plan view on a surface corresponding substantially to the surface of said aggregated layer (7) to be transferred.

56. Apparatus (1) according to any one of claims 42 to 55, wherein said preparation means furthermore comprises first moulding means (6, 8, 9) suitable for stably shaping along a substantially vertical plane the lateral limits (10) of said aggregated layer (7) .

57. Apparatus (1) according to any one of claims 42 to 56, wherein said preparation means furthermore comprises second moulding means (13) suitable for stably shaping according to substantially vertical planes the frontal limit (18, 18a) of said aggregated layer (7) .

58. Apparatus (1) according to any one of claims 42 to 57, wherein said preparation means furthermore comprises separating means (13) suitable for cutting the most advanced portion (P) of said aggregated layer (7) of a length (L) corresponding to the length of said tile.

59. Apparatus (1) according to preceding claim, wherein said second moulding means (13) and said separating means are integrated into a cutting-blade device (13) .

60. Apparatus (1) according to preceding claim wherein said cutting-blade device (13) is comprised in said frame (12, 13) .

61. Apparatus (1) according to any one of claims 53 to 60, wherein said frame (12, 13) has substantially vertical external walls and divergent internal walls spreading out towards the bottom.

62. Apparatus (1) according to any one of claims 42 to 61, wherein said preparation means comprises pressing means (8) suitable for aggregating said granular material (5) .

63. Apparatus (1) according to any one of claims 42 to 62, wherein said surface (2) cooperates with moving means suitable for moving it in a vertical direction (Y) .

64. Apparatus (1) according to any one of claims 42 to 63, wherein said surface (2) consists of a belt with an impermeable surface.

65. Apparatus (1) according to any one of claims 42 to 63, wherein said surface (2) consists of a belt with a permeable surface.

66. Apparatus (1) according to any one of claims 42 to 65, wherein said granular material (5) is mixed with substances in liquid or semi-plastic state intended to constitute, following treatment, the binder of the finished tile.

67. Apparatus (1) according to any one of claims 42 to 66, wherein said tiles are ceramic tiles.

68. Method for transferring granular material (5) to a mould for pressing (14) tiles, that comprises preparing on a surface (2) that is movable in an advancing direction (X) a layer (7) of said granular material (5) , acting with a vacuum through a wall (15) for raising said layer (7) from said surface (2) , characterised in that it furthermore comprises widening openings (19) in said wall

(15) so that said openings (19) cannot remain obstructed (C, G) by particles of said granular material (5) and aggregating said granular material (5) so that it cannot flow away through said openings (19) that have been thus widened.

69. Method according to preceding claim, wherein said aggregating comprises mixing said granular ' material (5) with substances in liquid or semi-plastic state intended to constitute, following treatment, the binder of the finished tile.

70. Method according to any one of claims 68 or 69, wherein said aggregating comprises tamping said granular material

(5) on said movable surface (2) .

71. Method according to any one of claims 68 to 70, which is applied to the production of ceramic tiles.

72. Method for transferring granular material (55) to a pressing mould (57) that comprises preparing a layer (54) of said granular material (55) on a surface (52) that is movable in an advancing direction (X, Xl) that is coplanar with said surface (52) , filling with said layer

(54) a room (61) above said surface (52) , acting with vacuum means for keeping said layer (54) raised in said room (61) and transferring them together, characterised in that said filling occurs through an approach movement between said layer (54) and said room (61) in a direction parallel to said advancing direction (X, Xl) .

73. Method according to preceding claim, characterised in that it furthermore provides for modelling recesses (63) and/or protrusions (64) on the surface that defines the bottom (60) of said room (61) so as to modify locally the height of said room (61) and obtain corresponding local variations in the thickness (Sl, S2) of said granular material (55) to be transferred.

74. Method according to the preceding claim, characterised in that said modelling comprises applying to said surface of the bottom (60) of said room (61) bodies (64) fixed in a removable and interchangeable way.

75. Method according to any one of claims 72 to 74, characterised in that during said filling it provides for keeping open said room (61) in the movable wall (59) facing upstream with respect to said advancing direction

(X, Xl) . ^■

76. Method according to preceding claim, characterised in that it provides closing said room (61) lowering said movable wall (59) when said room (61) is full of said granular material (55) .

77. Method according to preceding claim, characterised in that said filling comprises positioning said room (61) on said surface (52) when the front (B) of said advancing layer (54) has already gone past the position (C) where said closing with said movable wall (59) is provided.

78. Method according to any one of claims 72 to 77, characterised in that said preparing comprises arranging said layer (54) without lateral containing and with width dimension (Zl) the same as or less than the width (V) of said room (61) .

79. Method according to any one of claims 72 to 78, characterised in that said preparing comprises arranging said layer (54) on a width (Zl) in excess with respect to the width (V) of said room (61) and said filling comprises transporting said excess inside said room (61) .

80. Method according to any^' one of preceding claims 72 to 78, characterised in that said preparing comprises arranging said layer (54) between lateral containing means (70) on a width (Zl) substantially corresponding to the width (V) del said room (61) and said filling comprises moving said room (61) in said direction (X2) parallel to said advancing direction (X, Xl) between said lateral containing means (70) .

81. Method according to any one of preceding claims 72 to 78, characterised in that said preparing comprises arranging said layer (54) between lateral containing means (70) on a width (Zl) substantially corresponding to the width (V) del said room (61) and said filling comprises moving said lateral containing means (70) in said direction (X2) parallel to said advancing direction ^"(X₇ Xl) together with said room (61) .

82. Method according to any one of claims 72 to 81, characterised in that during the entire cycle the surface

(52) is kept in constant and uniform movement along said advancing direction (Xl) .

83. Method according to any one of claims 72 to 82, characterised in that during said filling said room (61) is moved in a direction (X2) opposite said advancing direction (X, Xl) of said surface (52) .

84. Method according to any one of claims 72 to 83, characterised in that said preparing comprises forming said layer (54) with a greater thickness along the two marginal strips (H) .

85. Method according to any one of claims 72 to 84, that comprises transferring said room (61) keeping it adjacent to said surface (52) .

86. Method according to any one of claims 72 to 85, characterised in that during said transferring said room (61) is moved in said advancing direction (Xl) at a speed (X3) that is greater than the advancing speed of said surface (52) .

87. Method according to any one of claims 72 to 86, characterised in that said transferring comprises centring said room (61) above a mould cavity (57) for pressing said granular material (55) .

88. Method according to any one of claims 72 to 87, characterised in that said preparing comprises providing stratification with lower permeability at the base of said layer (54) .

89. Method according to any one of claims 72 to 88, characterised in that it is applied in the production of ceramic material .

90. Method according to any one of claims 72 to 89, characterised in that it is applied in the production of roof tiles (65) .

91. Apparatus for transferring granular material (55) to a pressing mould (57) comprising, a movable surface (52) in an advancing direction (X, Xl) , preparation means suitable for preparing on said movable surface (52) a layer (54) of said granular material (55) , a transferring means (56) provided with a room (61) open below cooperating with vacuum means suitable for keeping said granular material (55) raised and transferring it to said mould (57) , characterised in that said room (61) has an access opening for said layer (54) on the side upstream said advancing direction (X, Xl) .

92. Apparatus according to preceding claim, characterised in that said access opening is closable with a movable wall (59) .

93. Apparatus according to preceding claim, characterised in that said wall (59) is movable sliding vertically (W) .

94. Apparatus according to any one of claims 91 to 93, characterised in that said room (61) is defined above by a permeable baffle (60) through which said vacuum means

5 acts .

95. Apparatus according to claim 23, characterised in that said permeable baffle (60) has protrusions (64) and/or recesses (63) so as to define locally various heights

(Sl, S2) of said room (61) .

10 96. Apparatus according to preceding claim, characterised in that said protrusions (64) and/or recesses (63) are defined by bodies fixed in a removable manner.

97. Apparatus according to any one of claims 91 to 96, characterised in that the surface that defines said room

15 (61) above is formed with longitudinal recesses (68) adjacent to said lateral walls (58) .

98. Apparatus according to any one of claims 91 to 97, characterised in that said preparation means is suitable for arranging said layer (54) without lateral containing

20 and with width dimension (Zl) the same as or less than the width (V) of said room (61) .

99. Apparatus according to any one of claims 91 to 98, characterised in that said preparation means is suitable for arranging said layer (54) with a width dimension (Zl)

25 that is greater than the width (V) of said room (61) .

100. Apparatus according to any one of claims 91 to 99, characterised in that said transferring means (56) comprises deviating means (69) suitable for conveying said layer (54) inside said room (61) ; 30

101. Apparatus according to preceding claim, characterised in that said deviating means (69) are extensions of the two said lateral walls (58) .

102. Apparatus according to any one of claims 91 to 101, wherein said preparation means is suitable for moulding 35 said layer (54) with a greater thickness in the two marginal strips (H) adjacent to the slopes (67) of said layer ( 54 ) .

103. Apparatus according to any one of claims 91 to 102, characterised in that said preparation means comprises lateral containing means (70) spaced by a dimension (Zl) substantially corresponding to the width (V) of said room (61) and said room (61) is longitudinally movable between said lateral containing means (70) .

104. Apparatus according to any one of claims 91 to 103, characterised in that said preparation means comprises lateral containing means (70) spaced by a dimension (Zl) substantially corresponding to the width (V) of said room (61) and said lateral containing means (70) is longitudinally movable together with said room (61) .

105. Apparatus according to any one of claims 91 to 104, characterised in that it is used in the production of ceramic material.

106. Apparatus according to any one of claims 91 to 105, characterised in that it is used in the production of roof tiles (65) .