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Title:
PRESSING ASSEMBLY FOR THE PRODUCTION OF LARGE TILES
Document Type and Number:
WIPO Patent Application WO/2021/019439
Kind Code:
A1
Abstract:
The pressing assembly (1) for the production of large tiles comprises: - a supporting plane (3) of a ceramic material (4) to be pressed; - a holding plate (2) defining an abutment surface (20) turned towards the supporting plane (3) and provided with at least one cavity (24) for housing magnetic windings (21) operable to activate a magnetic field, the cavity (24) facing the abutment surface (20); - a pad (5) made of ferromagnetic material associable with the holding plate (2) and adapted to lean against the abutment surface (20) and to be held by means of the magnetic field; the holding plate (2) and the supporting plane (3) being movable in mutual approach/away direction; and comprises: - closing means (23) of the rigid type adapted to counteract the force exerted by the pad (5) and inserted in the cavity (24) that define a closing surface (23a) substantially aligned and coplanar to the abutment surface (20), where the cavity (24) comprises a first seat (24a) facing the abutment surface (20) and adapted to house the closing means (23) and a second seat (24b) for housing the magnetic windings (21), where the seats (24a, 24b) are communicating with each other and where the second seat (24b) is of the blind type, the first seat (24a) being wider than the second seat (24b) and defining a leaning surface (24c) for the closing means (23).

Inventors:
TAROZZI FABIO (IT)
Application Number:
IB2020/057106
Publication Date:
February 04, 2021
Filing Date:
July 28, 2020
Export Citation:
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Assignee:
SITI B & T GROUP SPA (IT)
International Classes:
B28B3/02; B28B7/00; B28B7/36; B28B17/00; B30B15/02; B30B15/28
Foreign References:
US20180297314A12018-10-18
IT1125984B1986-05-14
ES1054487U2003-07-16
EP0310692A11989-04-12
Attorney, Agent or Firm:
ZOLI, Filippo (IT)
Download PDF:
Claims:
CLAIMS

1) Pressing assembly (1) for the production of large tiles comprising:

a supporting plane (3) of a ceramic material (4) to be pressed;

a holding plate (2) defining an abutment surface (20) turned towards said supporting plane (3) and provided with at least one cavity (24) for housing magnetic windings (21) operable to activate a magnetic field, said cavity (24) facing said abutment surface (20);

a pad (5) made of ferromagnetic material associable with said holding plate (2) and adapted to lean against said abutment surface (20) and to be held by means of said magnetic field;

said holding plate (2) and said supporting plane (3) being movable in mutual approach/away direction;

characterized by the fact that it comprises:

closing means (23) of the rigid type adapted to counteract the force exerted by the pad (5) and inserted in said cavity (24) that define a closing surface (23a) substantially aligned and coplanar to said abutment surface (20),

by the fact that said cavity (24) comprises a first seat (24a) facing said abutment surface (20) and adapted to house said closing means (23) and a second seat (24b) for housing said magnetic windings (21), where said seats (24a, 24b) are communicating with each other and where said second seat (24b) is of the blind type,

and by the fact that said first seat (24a) defines a leaning surface (24c) for said closing means (23), said first seat (24a) being wider than said second seat (24b).

2) Pressing assembly (1) according to claim 1, characterized by the fact that said closing means (23) are made of non-magnetic material.

3) Pressing assembly (1) according to claim 1 or 2, characterized by the fact that said closing means (23) are made of metal material.

4) Pressing assembly (1) according to one or more of the preceding claims, characterized by the fact that said closing means (23) are made of stainless steel.

5) Pressing assembly (1) according to one or more of the preceding claims, characterized by the fact that said closing means (23) have a thickness (S2) ranging between 10 mm and 30 mm. 6) Pressing assembly (1) according to one or more of the preceding claims, characterized by the fact that said closing means (23) have a size substantially corresponding to said first seat (24a).

7) Pressing assembly (1) according to one or more of the preceding claims, characterized by the fact that said cavity (24) is filled with resin (22) to block said magnetic windings (21) with respect to said magnetic plate (2).

8) Pressing assembly (1) according to one or more of the preceding claims, characterized by the fact that said pad (5) has a thickness (si) ranging between 5 mm and 30 mm, preferably 10 mm.

9) Pressing assembly (1) according to one or more of the preceding claims, characterized by the fact that said pad (5) has a coupling surface (50) intended to operate in conjunction with said abutment surface (20) and a work surface (51) opposite said coupling surface (50) and turned towards said supporting plane (3), and by the fact that said pressing assembly (1) comprises coating means (52) of said work surface (51).

10) Pressing assembly (1) according to claim 9, characterized by the fact that said coating means (52) are selected from the group comprising two-component polyurethane resins and vulcanisable rubbers.

11) Pressing assembly (1) according to claim 9 or 10, characterized by the fact that said coating means (52) define a substantially flat and uninterrupted pressing surface (52a) intended to contact the ceramic material to be pressed.

12) Pressing assembly (1) according to claim 9 or 10, characterized by the fact that said coating means (52) define a substantially flat pressing surface (52a), intended to contact the ceramic material to be pressed, and a perimeter edge (53) which is raised with respect to said pressing surface (52a).

13) Pressing assembly (1) according to one or more of the preceding claims, characterized by the fact that said supporting plane (3) is free of containment elements of the ceramic material (4) to be pressed.

14) Pressing assembly (1) according to claim 13, characterized by the fact that said supporting plane (3) defines a backing surface (30) of the ceramic material (4) to be pressed substantially flat and without interruption.

15) Pressing assembly (1) according to claim 13 or 14, characterized by the fact that said supporting plane (3) is of the type of a belt.

16) Pressing assembly (1) according to one or more of the preceding claims, characterized by the fact that said holding plate (2) comprises further cavities (27) arranged on opposite side to said cavity (24) wherein, each of said further cavities (27) is adapted to house further magnetic windings (26) to make a magnetic connection between said holding plate (2) and a support (6) of a tile production machine wherein said pressing assembly (1) is housed.

Description:
PRESSING ASSEMBLY FOR THE PRODUCTION OF LARGE TILES

Technical Field

The present invention relates to a pressing assembly for the production of large tiles.

Background Art

Typically, tile production comprises an initial pressing phase of ceramic powder mixtures obtained using a pressing assembly G, such as e.g. the one shown in Figure 1, provided with a pad T that presses and compacts the mixture arranged at a forming seat in the pressing assembly G. The mixture thus compacted forms a slab M of hardened material intended for the final firing in special kilns in order to make the finished tiles.

The pad T is usually made of steel so that it can be supported by the pressing assembly G by means of a magnetic plate P in the lower surface of which there are slots C for the housing of one or more magnetic windings A inserted inside the slots C themselves.

Due to the different resistance that the pad T encounters at the point where the slots C are located with respect to the remaining portions of the abutment surface of the plate P, besides the high forces involved, the pad T may undergo deformations at the point where the slots themselves are located.

It follows that a deformation of the pad T would transfer one or more defects to the slab M at the point where the grooves C are located, which would be visible, therefore, also on the surface of the finished tiles. To overcome this problem, in processes for the formation of small/medium tiles, it is known to increase the thickness of the pad T in order to increase the stiffness thereof and thus avoid the presence of localized deformations at the point where the grooves C are located.

Generally, therefore, there is a tendency to increase the thickness of the pad as the size of the tile to be made increases. As it can be easily guessed, as the thickness of the pad increases, so does its weight as well as the related manufacturing costs.

It has been seen that, while for small to medium sizes, e.g. from 300x300 mm to 1200x1200 mm, the pad thicknesses, which vary from about 27 mm to about 40 mm, do not affect excessively the manufacturing costs, this is no longer the case for the so-called medium-large sizes, i.e. with a surface area of about 2 m 2 or more.

For example, in the case of tiles measuring 2500x1260 mm or 3600x1800 mm, the thickness of the pad required to prevent the formation of locali ed deformations would be around 46-47 mm, with a relevant weight ranging from approximately one tonne to over two tonnes, respectively.

It is therefore easy to see how, in the case of large tiles, the amount of masses involved would lead to excessive manufacturing costs, not only related to the construction of the pad but also to the sizing of the entire pressing assembly. Description of the Invention

The Applicant has therefore decided to introduce high resistance closing means inside the slots in order to increase the compressive strength at the point where the slots of the plate are located, thus reducing the possibility of deformation of the pad without the need to increase the thickness thereof in order to remedy the above mentioned defects. Pads with lower thickness make it possible to keep manufacturing costs low while allowing the production of large tiles without the presence of defects.

The present invention therefore relates to a pressing assembly for the production of large tiles according to claim 1, which allows the drawbacks mentioned with reference to the prior art to be overcome.

Brief Description of the Drawings

Other characteristics and advantages of the present invention will be more evident from the description of a preferred, but not exclusive, embodiment of a press for the production of tiles illustrated by way of an indicative, yet non limiting example, in the attached tables of drawings in which:

Figure 1 is a front sectional view of a pressing assembly according to a known embodiment;

Figure 2 is a front sectional view of a pressing assembly according to the present invention;

Figure 3 is a front sectional view of the pressing assembly of Figure 2 during a pressing phase; Figure 4 is a front sectional view of a further embodiment of a pressing assembly according to the present invention;

Figure 5 is a front sectional view of a further embodiment of the pressing assembly plate in Figure 2.

Fmbodiments of the Invention

With particular reference to these figures, reference numeral 1 globally indicates a pressing assembly for the production of large tiles according to the present invention.

In the remainder of the present description and in the subsequent claims, the words“forward”,“backward”,“right”,“left”,“ upper” and“lower” are to be understood by reference to the directions shown in the drawings, but are not to be taken to be restrictive in any particular direction but are to be used for descriptive convenience only.

In the following description and in the subsequent claims, a large tile is defined as a tile with a size of approximately 1 m 2 . In this description, therefore, tiles ranging from 1000 x 1000 mm and above are considered large tiles. Examples of large tile sizes may comprise sizes of 3600 mm x 1800 mm or 2500 mm x 1260 mm respectively, or yet 1260 mm x 1260 mm.

The pressing assembly 1 is intended to be housed in a tile production machine (not shown) and comprises a holding plate 2 and a supporting plane 3 of a ceramic material 4 to be pressed arranged horizontally and parallel to each other. In particular, the holding plate 2 and the supporting plane 3 comprise an abutment surface 20 and a backing surface 30, respectively, facing each other and substantially rectangular in shape. The holding plate 2 also comprises an upper surface 25 opposite the abutment surface 20. Preferably, the surfaces 20,30 are substantially flat.

The supporting plane 3 is advantageously free of containment elements of the ceramic material 4 to be pressed. In other words, the supporting plane 3 is open at the side.

More in detail, the backing surface 30 defined by the supporting plane 3 is substantially flat and without interruption.

Appropriately, the supporting plane 3 is of the type of a belt movable along a direction of forward movement of the ceramic material.

Preferably, the holding plate 2 is arranged on top of the supporting plane 3 and is connected to actuation means, not shown in the figure, which allow the movement of the holding plate 2 away from and close to the supporting plane 3 along the longitudinal direction X-X.

To make the tiles, the holding plate 2 is moved away from the supporting plane 3, using the actuation means, so that the ceramic material 4 can be inserted on the backing surface 30 of the supporting plane 3 to press it.

Conveniently, the holding plate 2 supports a pad 5 which is designed, when the holding plate 2 approaches the supporting plane 3, to come into direct contact with the ceramic material 4 arranged on the backing surface 30 of the supporting plane 3. The pad 5 has a substantially parallelepiped shape and comprises a coupling surface 50 and a work surface 51 opposite each other and having sizes substantially corresponding to those of the tile to be made. In particular, the coupling surface 50 is in direct contact with the abutment surface 20 of the holding plate 2, while the work surface 51 faces the supporting plane 3 so that, in use, it can come into contact with the ceramic material 4 to press it. The connection between the holding plate 2 and the pad 5 is made by means of the presence of magnetic windings 21 which allow the holding plate 2 to hold or release the pad 5 by generating a magnetic force, preferably variable. For this purpose, the pad 5 is made of ferromagnetic material, such as a metal material, e.g. steel.

According to a preferred embodiment, the pad 5 has, advantageously, a reduced thickness si ranging between 5 and 30 mm, preferably about 10 mm. For example, a pad with a thickness of 10 mm and sizes of 3600 mm x 1800 mm has a weight of approx. 509 kg. With the sizes being the same, a pad with a thickness of 46 mm weighs 2340 kg. As a result, the reduction in the thickness of the pad 5 allows the overall weight of the pressing assembly to be kept low. As shown in Figures 2 and 3, the holding plate 2 has one or more cavities 24 obtained from the abutment surface 20 of the holding plate 2 along the direction X-X by a predetermined depth so as to accommodate the magnetic windings 21. Preferably, the cavities 24 are filled with a resin 22 to cover the windings 21 so that, once hardened, it allows the windings 21 themselves to be blocked inside the cavities 24 in the magnetic plate 2.

The resin 22 used is generally, but not limited to, of the thermo- setting type. According to the invention, the pressing assembly 1 comprises one or more closing means 23 in order to increase the compressive strength at the point where each cavity 24 is located when the pressing assembly 1 operates on the ceramic material 4, as will be explained in detail later in the present description. More particularly, the closing means 23 comprise at least one closing element of the rigid type.

The closing element 23 is suitably selected from materials of the “high strength” type, where this term refers to a value of compressive strength (or yield strength) adapted to counteract the force exerted by the pad 5.

Appropriately, the closing element 23 is made of a non-magnetic material.

The closing means 23 are made e.g. of stainless steel.

Each closing element 23 thus operates as an abutment element of the pad 5 during the pressing phase of the ceramic material 4.

According to the invention, the closing element 23 therefore defines a relevant closing surface 23a which, with the closing element itself inserted into the respective cavity 24, is substantially aligned and coplanar to the abutment surface 20 of the holding plate 2.

Therefore, as shown in the example in Figure 2, once the closing element 23 is inserted into the respective cavity 24, the surfaces 23a and 20 are aligned and coplanar to each other. Thus, when the pad 5 is connected to the holding plate 2, the surface 23 a and the surface 20 are both in direct contact with the coupling surface 50 of the pad 5.

For example, the closing element 23 is inserted into the cavity 24 by interference.

In addition, a sealing element, not shown in detail in the figures, can be inserted between the closing element 23 and the cavity 24.

Alternative embodiments for fastening the closing element 23 in the relevant cavity 24 cannot however be ruled out.

Preferably, each closing element 23 extends vertically along X-X by a thickness s2 of predetermined length ranging between 10 and 30 mm and is made of rigid, high-strength material to strengthen the compressive strength of the holding plate 2 at the point where the cavities 24 are located.

In the preferred embodiment shown in the figures, the cavities 24 have a substantially inverted T shape. In particular, the transverse dimensions of the cavities 24 vary along the depth. More specifically, the transverse dimensions are maximum starting from the surface 20 of the plate 2 and remain constant by a section with depth substantially corresponding to the thickness s2 of the corresponding closing element 23, so that the latter can be completely housed in this section of the cavity 24.

Still according to the invention, the cavity 24 comprises a first seat 24a facing the abutment surface 20 and adapted to house the closing means 23 and a second seat 24b for housing the magnetic windings 21, wherein the seats 24a, 24b are communicating with each other and wherein the second seat 24b is of the blind type.

In addition, the first seat 24a is wider than the second seat 24b and defines a stop surface 24c for the closing means 23. The closing means 23, after being inserted into the first seat 24a, then rest against the stop surface 24c, which operates as an abutment by counteracting the thrust exerted by the ceramic material 4 during the pressing phase.

This way, the cavity 24 therefore defines two seats 24a and 24b: the first seat 24a is adapted to receive by shape coupling the closing means 23 and has a width substantially corresponding to the closing means themselves; while the second seat 24b has a smaller width than the first seat 24a and is adapted to contain the magnetic windings 21.

Appropriately, each closing element 23 has a width that substantially coincides with the width of the cavities 24 closest to the abutment surface 20 of the holding plate 2 so that the closing elements 23 may insert into the corresponding cavities 24 by shape coupling.

Alternative embodiments cannot however be ruled out wherein, e.g., each cavity 24 has a constant width, transverse to the direction X-X, along the entire depth. As shown in Figure 3, the tile production process involves, after the insertion of the ceramic material 4 on the backing surface 30 of the supporting plane 3, a phase in which the pad 5 is moved towards the supporting plane 3 to press the ceramic material 4. The pad 5 comes into contact with the ceramic material 4 and exerts a force on the latter by compressing it against the supporting plane 3, thus forming a slab of compact material. Since the supporting plane 3 reacts to the compressive force with an equal and opposite force, the latter is transmitted from the slab to the pad 5 and from the latter to the abutment surface 20 of the holding plate 2. Thanks to the fact that each closing element 23 is made of rigid material, the abutment surface 20 of the holding plate 2 maintains a high surface homogeneity such that the pad 5, even when subjected to very high pressures, is not deformed despite its limited thickness.

According to a further embodiment, coating means 52 are provided, e.g. of the type of a resin, of the work surface 51 of the pad 5, showing the negative face of the tile to be produced.

Advantageously, the use of special resins, e.g. of the type of two-component polyurethane resins or the type of vulcanisable rubber, makes it possible to manufacture a pad 5 that is easy to clean as the dust does not stick to the resin of the pad 5 after pressing. In particular, the pad 5, being shaped by the resin 52, marks the plate 4, during the pressure phase, by transferring the desired shape thereto.

The coating means 52 therefore define a pressing surface 52a, intended to contact the ceramic material 4, substantially flat (i.e. unless any processing adapted to give it a structured appearance to be transferred to the tile to be formed) and without interruption.

In this embodiment, shown in Figure 2, the pressing surface 52a thus extends over the entire area of the work surface 51 and is free of protrusions or perimeter edging.

This way, it is possible to shape the pad by avoiding the presence of reinforced edges as the pressing method used for the production of large sizes does not particularly affect the wear of the pad edges compared to the wear caused by the production of a medium/small size tile. This way, the pad can be manufactured without complicated mechanical processing at an extremely low cost.

In the alternative embodiment shown in Figure 4, on the other hand, the coating means 52, besides defining the pressing surface 52a substantially (i.e. unless any work is carried out to give it a structured appearance to be transferred to the tile to be formed) flat, also define a perimeter edge 53 which is protruding from the pressing surface 52a. It is thus possible to obtain a perimeter reinforcement on the edge of the pressed slab.

With reference to the example in Figure 5, a further embodiment is shown with further cavities 27 obtained above the holding plate 2 opposite the cavities 24. In particular, in the holding plate 2, one or more further cavities 27 are obtained starting from the upper surface 25 of the holding plate 2 by a predetermined depth so as to accommodate additional magnetic windings 26.

In particular, the upper surface 25 is intended to be connected to a support 6 of the tile production machine in which the pressing assembly 1 is housed.

The connection between the holding plate 2 and the support 6 is advantageously made by means of the presence of additional magnetic windings 26 which allow the holding plate 2, by generating a variable magnetic force, to hold or release with respect to the support 6. For this purpose, the support 6 is preferably made of metal material such as steel or other ferromagnetic material.

Preferably, the further cavities 27 are filled with a resin 28 to cover the additional windings 26 so that, once hardened, it allows the additional magnetic windings themselves to be blocked inside the further cavities 27 in the holding plate 2.

As can be seen from the present description, it has been ascertained that the described invention achieves the intended objects and, in particular, the fact is underlined that a relatively thin pad can be used to make large tiles without surface defects by means of the closing means. Moreover, the presence of grooves even above the plate allows the assembly /removal of the latter from the machine where the pressing assembly is housed, thus facilitating the maintenance operations of the pressing assembly.