ES2648517T3 - Mold to form tiles and the like - Google Patents

Abstract

Mold (10, 110) for forming tiles and the like, comprising a lower half-mold (11, 111) and an upper half-mold (12, 112) defining at least one formation cavity (13), comprising at least one of the two semi-molds a support plate (16, 116) with at least one seat (17, 117) into which a press block (18, 118) can be sealed, with a chamber being formed between the block and the bottom of the seat (20, 120) intended to receive incompressible fluid to push the block out of the seat, elastic means (21, 121) being present between the plate and the peripheral edge of the block to elasticly push the block towards the bottom of the seat , characterized in that the elastic means comprise a projection (22, 122) that protrudes laterally from the peripheral edge of the block and is connected to the plate by means of connecting pins (23, 123) with arrangement, between them, of at least one elastic separator or (24, 124) that opposes the sliding of the block towards the outside of the seat on the plate, the elastic separator (24, 124) being formed by a layer of elastomeric material and the protrusion being formed as a frame surrounding the block (18, 118) as one or two pieces.

Description

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DESCRIPTION

Mold to form tiles and the like

The present invention relates to a mold for forming tiles and the like.

In the art, molds are known in which a pair of semi-molds are combined to form one or more cavities to receive the spilled powder that, once pressed, forms the ceramic product. Since the density of the powder can vary, for various reasons, within the cavity or between a cavity and another of the mold, for some time the so-called "isostatic" molds have been proposed in which, in at least one half-mold, the block Pressing that supports the mold matrix rests on a bed of incompressible fluid present in the chamber behind the block. The volume of oil inside the chamber, which is varied appropriately during pressing, allows the degree of compaction of the powder inside the mold to be varied. Generally, in the case of multi-print molds, the various support blocks for each print have interconnected fluid beds such that there is an automatic compensation of the density between the various mold prints.

EP 1403017 describes a mold of the type mentioned above according to the preamble of claim 1, which uses elastic sheets that are coupled within the side walls of the blocks to push the latter into their most retracted position. When the sheets are in a non-deflected state the block is in its most retracted position. By supplying fluid inside the chamber behind the block, the block moves outward, causing the elastic sheets to flex.

Pushing the blocks elastically to the most retracted position is useful, for example, to keep all pressing dies at the same height during powder filling operations. In addition, it is possible to use the isostatic mold as a conventional mold simply by completely removing the incompressible fluid. In the case where there is no fluid or low fluid pressure, it is also possible to prevent the blocks from making uncontrolled movements on their support plates.

However, the use of elastic sheets is subject to various disadvantages.

For example, the displacement allowed by the sheets is very limited and the sheets are subjected to bending which easily causes them to break, resulting in the need for frequent maintenance of the mold.

On the other hand, the space around mold impressions is restricted and it is difficult to conceive of alternative systems.

In addition, the sheets have an elastic behavior, which is not suitable to guarantee a uniform filling of the mold, said behavior being too critical, in particular after several pressing cycles.

US6093012 discloses a mold for manufacturing concrete moldings having a pressure plate that is suspended by screws on which helical compression springs are mounted.

US4588368 discloses a molding apparatus in which a pre-compression matrix is returned by bolts that are prestressed by helical compression springs.

The general objective of the present invention is to provide a mold with an isostatic plate provided with elastic means for carrying out the thrust towards the rest position, said means being small in size, robust and efficient.

In view of this objective, the idea that has been conceived, according to the invention, is to provide a mold for forming tiles according to claim 1.

In order to more clearly illustrate the innovative principles of the present invention and their advantages compared to the prior art, examples of embodiments that apply these principles will be described below, with the help of the accompanying drawings. In the drawings:

- Figure 1 shows a longitudinal, schematic and partial sectional view of a first embodiment of a mold according to the invention;

- Figure 2 shows a partially cross-sectional and enlarged view of the mold according to Figure 1;

- Figure 3 shows a schematic, perspective and partial view of the mold according to Figure 1;

- Figure 4 shows a schematic, perspective, exploded and partial view of the mold according to Figure 1;

- Figure 5 shows an enlarged and partial view of a variant of the mold according to Figure 1;

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- Figure 6 shows a longitudinal, schematic and partial sectional view of a second embodiment of a mold according to the invention;

- Figure 7 shows a schematic, perspective and partial view of the mold according to Figure 6;

- Figure 8 shows a schematic, perspective, exploded and partial view of the mold according to Figure 6;

- Figure 9 shows an enlarged and partial view of a variant of the mold according to Figure 6.

With reference to the figures, Figure 1 shows a mold, generally designated by 10, to form tiles and the like (usually by pressing a suitable powder material). For simplicity, the figure only shows the right part of the mold, the left part being generally a mirror image thereof (if the mold is of the single row type).

The mold 10 comprises a lower half mold 11 and an upper half mold 12 defining at least one forming cavity 13 within which the material is pressed.

The two half-molds are generally intended to be mounted on respective pressing surfaces 14, 15 of a suitable press, not shown since it can easily be imagined by one skilled in the art.

At least one of the two half-molds comprises a support plate 16 which has at least one seat 17 that contains so that a pressing block 18 provided to support thereon a die 19 with a half-impression of the product that can be slidably seated. It will form. Generally the semi-print coincides with one of the two sides of a tile, while the side edge is obtained by a containment frame 31 in which the matrices are inserted.

The example according to Figure 1 shows an upper half-mold, but the same solution can be used for the lower mold alone, or for both, depending for example on the specific practical needs and requirements.

Therefore, a chamber 20 which is intended to receive incompressible fluid to push the block out of the seat is formed between the block and the bottom of the seat, according to the conventional mode of operation of isostatic plate molds. Elastic means 21 for pushing the block elastically towards the bottom of the seat are present between it and the peripheral edge of the block.

Advantageously, these elastic means are distributed around the lateral perimeter of the block to provide a uniform thrust action along the periphery of the block, as can be seen more clearly in Figure 3 and as will be further clarified below.

As can be clearly seen again in Figure 1 and in a partially cross-sectional view from a direction rotated 90 ° in Figure 2, the elastic means comprise a projection 22 protruding laterally from the peripheral edge of the block 18 and which is connected to the plate by means of connecting pins 23 with the arrangement, between them, of an elastic separator 24 that opposes the sliding of the block towards the outside of the seat formed in the plate. Therefore, the block can perform its sliding movement (in a vertical direction in the figure), sliding inside the seat on the plate parallel to the pins, to engage inside the seat against the action of the oil or (compressing the elastic element 24 when the fluid enters the chamber 20) to further protrude from the seat.

In the first embodiment described, the pin 23 advantageously slides through the projection 22 and is fixed on the plate by means of a first end 25 thereof. Said elastic separator 24 is present between the second opposite end 26 of the pin and the projection 22 and therefore reacts between said second end of the pin and the projection to oppose the sliding of the block towards the outside of the seat formed in the plate.

Advantageously, the pin is formed as a screw that is screwed into the plate 16 (provided with suitable threaded holes) and has an enlarged head forming said second end 26. The elastic spacer 24 advantageously presses against the screw head by means of a metal support sheet 27. Again advantageously, rigid tubular bearings or spacers 28 are mounted on the screws 23 to limit screw screwing. In this way the screws can be screwed firmly into the plate without tensioning the elastic separator. Advantageously, the rigid separators are suitably designed with longitudinal dimensions compared to the thickness of the elastic separator to allow the prestressing of said elastic separator to be controlled.

As can be clearly seen in Figure 3 and, more particularly, in the exploded view of Figure 4, the support sheet 27 is advantageously in the form of a frame that follows the perimeter of the block and in which the screws 23 The pins that form are screwed at intervals along their length to surround the block. The size of the mold can be such that, when the block is pushed completely into the seat by elastic means 21, the block is disposed against the bottom of the seat.

However, it may be advantageous if there is a small distance between the block and the bottom of the seat, for

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example in order to facilitate the subsequent entry of the fluid or avoid any "adhesion" of the block to the bottom of the seat. This space (designated by "d" in the figure) can also be only of the order of a few tenths of a millimeter.

In order to prevent contact between the block and the bottom of the seat, an end-of-travel stop is advantageously provided, which is easily obtained by contacting the projection 22 against the edge of the plate 16 surrounding the block, such as can be seen in figures 1 and 2.

The projection is formed as a frame that surrounds the block as one or two pieces (Figures 3 and 4 show a projection consisting of two pieces) and which preferably rests against a contact edge 30 present in the block side walls that protrude from the block seat on the plate. The contact edge can advantageously form part of a groove present in the side walls of the block and into which said frame is partially inserted.

The elastic separator is formed by a layer of elastomeric material, chosen in particular from polyurethane elastomers (for example: ADIPRENE®, VULKOLLAN®, ADIPOL®, ULTRAFLEX®) or NBR (nitrile butadiene rubber).

As can be clearly seen in Figure 4, it has also been found that it is advantageous if the layer of elastomeric material follows the perimeter of the block to be crossed at intervals by the pins that extend along its length. For example, the elastomeric layer can be easily cut in the form of a generally rectangular frame from a sheet of suitable thickness.

Again advantageously, the elastomeric material layer, the projection and the support sheet can all be in the form of a frame with a similar impression to completely overlap each other, as can be clearly seen again in the exploded view of the figure 4.

Figure 4 shows how the blocks can be advantageously at least in a number of two (and advantageously also a set of blocks arranged in rows and columns to form a matrix of press prints). Each block can slide in its seat on the plate and has its own elastic means along the perimeter. The respective chambers intended to receive incompressible fluid are interconnected by means of conduits 32, according to the arrangement designed for this type of mold.

Figure 5 shows a variant in which an elastic deformation element 29 is disposed between the projection 22 and the plate 16, allowing said element to keep the block elastically separated from the bottom of the seat a distance "d" also before the introduction of oil Advantageously, the deformation factor and the thickness "D" of the element 29 (which can be a layer of deformable material arranged along the entire length of the projection 22) are chosen so that the pressing forces generated during the use of the mold can compress the elastic element 29 and eliminate the distance "d". This allows the block to be brought into contact against the bottom of the seat, for example when there is no fluid inside the chamber (or when the fluid pressure is low enough) or when fluid transfer occurs to the chambers of the other blocks. Therefore, this results in the above-mentioned advantages of a small space between the block and the bottom of the seat when the mold is in the resting state, while ensuring that the block moves smoothly towards the bottom of its seat. The material of the element 29 can be advantageously chosen from those that can be used for the elastic separator 24.

Figure 6 shows a second embodiment of a mold according to the invention.

This figure shows only partially the lower half-mold, it is easy for the person skilled in the art to imagine the overall overall structure of the mold based on the description provided so far and below. With the embodiment in Figure 6 it is possible to obtain an even smaller vertical dimension and is therefore particularly useful for the lower half-mold. In any case, the same solution can be used for the upper mold alone or for both molds.

For simplicity, parts similar to those of the previous embodiment will be indicated by the same number, increased by 100.

Thus, Figure 6 shows the half-mold 111 of a mold 110 provided according to the invention to form tiles and the like.

The half-mold comprises a support plate 116 with at least one seat 117 containing so that a pressing block 118 provided to receive, mounted thereon, a die 119 with a semi-impression of the product to be formed can be slidably sealed. . The half-print is combined (together with the other half-mold, not shown) to form the formation cavity (13 in Figure 1) of the complete mold.

A chamber 120 is formed between the block and the bottom of the seat and is intended to receive incompressible fluid to push the block out of the seat.

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Elastic means 121 are present between the plate and the peripheral edge to elasticly push the block towards the bottom of the seat.

In the same way as for the previous embodiment, the elastic means are advantageously distributed around the lateral perimeter of the block, as can be seen, for example, in Figure 7.

The elastic means comprise a projection 122 protruding laterally from the side walls of the block 118 and which is connected to the plate by means of connecting pins 123 with the arrangement, between them, of at least one elastic separator 124 opposing the sliding of the block towards the outside of the seat formed in the plate. Therefore, the block can perform its sliding movement (in a vertical direction in the figure), sliding inside the seat on the plate, to engage inside the seat against the action of the oil or (compressing the elastic element 124 when the fluid enters chamber 120) to further protrude from the seat.

As can be clearly seen again in Figure 6, the pin 123 is connected to the projection by means of a first end 125 thereof and slides through the plate 116. The elastic separator 124 is present between the second end. opposite 126 of the pin and the plate 116 and therefore reacts between the second end of the pin and the plate to oppose the sliding movement of the block towards the outside of the seat in the plate.

Advantageously, the pin is formed as a screw with an enlarged head that forms said first end 125 and with a second end 126 that is screwed on a sheet 127 that rests against the elastic separator 124.

Advantageously again, bearings or rigid tubular separators 128 for limiting screw screwing and controlling prestressing of the elastic separator are mounted on screws 123. In this way the screws can be screwed tightly without tensioning the elastic separator thanks to a suitable choice of Bearing length The screw heads can be tapered and received inside widened seats in the projection, as can be seen in the figures.

As can be deduced from Figure 7 and is clearly seen in the exploded view of Figure 8, the support sheet 27 is advantageously in the form of a frame that follows the perimeter of the block and into which the screws 123 that form the pins at intervals along their length to surround the block.

In a similar way, it can be seen how the projection 122 can also be advantageously in the form of a frame that surrounds the periphery of the block, with the screws arranged at intervals passing through it.

Advantageously, the support sheet 127 is seated within a channel 140 formed in the plate, together with the elastic separator 124 (advantageously formed as a continuous frame with a progression similar to that of the sheet 127).

As with the previous solution, the size of the mold can be such that, when the plug is pushed completely into the seat by means of elastic means 121, the block is arranged against the bottom of the seat, but it may be advantageous for a small distance to remain between the block and the bottom of the seat.

In order to prevent contact between the block and the bottom of the seat, an end-of-travel stop is advantageously provided, which is easily obtained by contacting the projection 122 against the edge of the plate 116 surrounding the block, such as can be clearly seen in figure 6.

The projection is formed as a frame that surrounds the block and which preferably rests on a contact edge 130 present in the block side walls that protrude from the seat block in the plate. The contact edge can advantageously form part of a groove present in the side walls of the block and into which said frame is partially inserted. In particular, as can be clearly seen in the figures, the block can be formed with two overlapping and interconnected plates to fully tighten between them the innermost edge of the projection, while ensuring that the system can be assembled when the projection is formed As one piece.

In this second solution the elastic separator is also formed by a layer of elastomeric material, chosen in particular from polyurethane or NBR elastomers (nitrile-butadiene rubber) which is advantageously shaped (for example, cut from a sheet) to follow the perimeter of the block and cross at intervals by the pins along its length.

The possible frame-like shapes of the various pieces that form the elastic means can be clearly seen in Figure 8.

Figure 7 shows how the blocks can be advantageously at least in a number of two (and advantageously also a set of blocks arranged in rows and columns to form a matrix of

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pressing impressions), each block being able to slide in its own seat on the plate and having its associated elastic means along the perimeter. The respective chambers intended to receive incompressible fluid are interconnected by means of conduits 132, according to the arrangement designed for this type of mold. In this way, there will be a redistribution of fluid during pressing that optimizes the pressing of the powder in the various cavities.

Figure 9 shows a variant in which an elastic deformation element 129 is advantageously arranged between the projection 122 and the plate 116, said element allowing the block to be elastically separated from the bottom of the seat a distance "d".

In a manner similar to the previous embodiment, the deformation factor and the thickness "D" of the element 129 (which can also be formed as a frame along the entire length of the projection 122) can be chosen so that the Pressing forces generated during the use of the mold can compress the elastic element 129 and eliminate the distance "d" so that, when pressed, the block can come into contact against the bottom of the seat, if necessary.

The material of the element 129 can be advantageously chosen from those that can be used for the elastic separator 124.

At this point it is clear how the previously defined objectives have been achieved.

For example, the mold according to the invention is strong, easy to maintain and assemble and has optimum elasticity and repeatability characteristics.

In particular, with a mold according to the invention it is possible to guarantee that the various mold matrices are all at the same height after loading with the powder, guaranteeing a more uniform product.

Therefore, the quality of the products obtained with molds according to the invention is higher.

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

In addition, it is possible to introduce oil into the isostatic plate to increase the distance of each block from the bottom of its seat in the plate and therefore also the volume of the oil chamber of each block: therefore it is also possible to guarantee isostatic behavior in the case of a high degree of non-uniformity during filling with the powder in the various mold impressions.

The mold can also be complemented with accessories in the form of known systems for loading the powder and unloading the pressed product and / or known isostatic systems (for example of the type known as "isostatic marks") to locally guarantee a uniform density of the powder within the cavity.

Claims (14)

10 15 2. 20 3. Four. 25 5. 30 6. 7. 35 8. 9. 40 10. eleven. Four. Five 12. 13. 14. fifteen. Mold (10, 110) for forming tiles and the like, comprising a lower half-mold (11, 111) and an upper half-mold (12, 112) defining at least one formation cavity (13), comprising at least one of the two semi-molds a support plate (16, 116) with at least one seat (17, 117) into which a press block (18, 118) can be sealed, with a chamber being formed between the block and the bottom of the seat (20, 120) intended to receive incompressible fluid to push the block out of the seat, elastic means (21, 121) being present between the plate and the peripheral edge of the block to elasticly push the block towards the bottom of the seat , characterized in that the elastic means comprise a projection (22, 122) that protrudes laterally from the peripheral edge of the block and is connected to the plate by means of connecting pins (23, 123) with arrangement, between them, of at least one elastic separator or (24, 124) that opposes the sliding of the block towards the outside of the seat on the plate, the elastic separator (24, 124) being formed by a layer of elastomeric material and the protrusion being formed as a frame surrounding the block (18, 118) as one or two pieces. Mold according to claim 1, characterized in that the connecting pin (23) slides through the projection (22) and is fixed on the plate (16) by means of a first end (25) thereof, being provided between a second opposite end (26) of the pin and the projection said elastic separator (24) reacting between said second end of the pin and the projection to oppose the sliding of the block towards the outside of the seat formed in the plate. Mold according to claim 2, characterized in that the pin (23) is formed as a screw screwed into the plate and with a head forming said second end (26) and against which the elastic separator is supported by a metal sheet (27) arranged between them. Mold according to claim 3, characterized in that the support sheet (27) is in the form of a frame that follows the perimeter of the block and into which the screws that form the pins are formed at intervals along its length. Mold according to claim 1, characterized in that the pin (123) is connected to the projection (122) by means of a first end (125) thereof, which slides through the plate (116), and between a second opposite end (126) of the pin and the plate (116) is said elastic separator (124) reacting between said second end of the pin and the plate to oppose the sliding of the block towards the outside of the seat formed in the plate. Mold according to claim 5, characterized in that the pin is formed as a screw with a head (125) forming said first end and with a second end (126) that is screwed on a sheet (127) that rests against the elastic separator Mold according to claim 6, characterized in that the support sheet (127) is in the form of a frame that follows the perimeter of the block and into which the screws that form the pins are formed at intervals along its length. Mold according to claim 7, characterized in that the support sheet is seated within a channel (140) formed in the plate. Mold according to claim 1, characterized in that a stop end stop is provided which prevents contact between the block and the bottom of the seat between the projection (22, 122) and the plate (16, 116). Mold according to claim 1, characterized in that an elastic deformation element (29, 129) for keeping the block elastically separated from the bottom of the seat is disposed between the projection (22, 122) and the plate (16, 116). Mold according to claim 1, characterized in that the elastic separator (24, 124) is formed by a layer of elastomeric material, preferably chosen from polyurethane or NBR elastomers. Mold according to claim 11, characterized in that the layer of elastomeric material follows the perimeter of the block to be crossed at intervals by the pins (23, 123) along its length. Mold according to claim 1, characterized in that the projection (22, 122) is a frame surrounding the block and resting on a contact edge (30, 130) present in the side walls of the block that protrudes from the seat of the block in the license plate. Mold according to claim 13, characterized in that said contact edge (30, 30) is part of a groove present in the side walls of the block and into which said frame is partially inserted. Mold according to claim 3 or 6, characterized in that rigid separators (28, 128) to limit the Threading the thymes are mounted on the thymes. 16. Mold according to claim 1, characterized in that the blocks are at least in a number of two, each within an associated seat on the plate and the respective chambers (20, 120) being to receive interconnected incompressible fluid. 5