ES2893104T3 - Method for pressing ceramic articles - Google Patents

Abstract

A method for pressing ceramic articles, comprising the following steps: depositing a load (S) of incoherent material on a conveyor belt (T); transporting the load (S) along a main direction (X); by means of a first leveler (2), push two lateral zones of the load (S) towards each other, perpendicular to the main direction (X), to form two stacks (As), basically parallel to the main direction (X), whose maximum level exceeds the level of the remaining areas of the load (S); characterized by moving both the belt (T) and the load (S) arranged on the belt (T) between two pressing bearings of the press (P) and pressing the load (S) directly on the conveyor belt (T) after the formation of stacks (As).

Description

DESCRIPTION

Method for pressing ceramic articles

The object of the present invention is a method for pressing ceramic articles, in particular plates, tiles and the like.

The invention is particularly advantageous in a method for pressing ceramic articles, devised by the applicant himself and known in the field by publication EP1500480, in which the powder material to be pressed is arranged in the form of a layer on a support plane made up of the upper face of a conveyor belt, which is slidably supported on a lower pressing element or bearing. The pressing is done with a pressing element or upper pad by interposing a closed-loop belt, the outer surface of which is directed towards the conveyor belt.

To delimit the perimeter of a pressing zone, the upper bearing is provided with a frame, fixed or replaceable, that projects downwards. In addition to delimiting the perimeter of the pressing zone, such a forming frame also has the task of generating in the load, after pressing, an edge characterized by a compaction or density of material greater than that of the internal zones, where by higher material density means a reduction in the total space occupied by the material. As is known, the presence of denser and more compact lateral zones considerably simplifies the removal and trimming of fillers after pressing. This occurs because the denser areas can perfectly resist, without crumbling, the removal of the incoherent material that is located along the external edges of the pressed filler, allowing the obtaining of precise, clear edges of the filler.

The currently available device, although efficient and functional, can be improved in terms of flexibility with respect to changing the size of the articles to be pressed. Indeed, in the currently available device, changing the size of the ceramic article requires changing the protruding frame for a shaped frame to carry out the pressing of the new size. This represents a drawback both in processing times, since the replacement of the frame requires stopping the pressing line, and in costs, since it requires the availability of a certain number of frames of different sizes.

WO2006/095249 discloses a method for pressing ceramic articles according to the preamble of claim 1 using a different pressing process, which provides for pressing in a mould. A box device is provided for transferring a load of material from a conveyor plane to a mould. The box device isolates and presses the load of material into the plane of the conveyor before transferring it to the mold.

The object of the present invention is to offer a pressing method according to claim 1 that allows to overcome the drawbacks mentioned above.

An advantage of the pressing method according to the present invention is that it allows a size change in considerably shorter times with respect to currently available devices.

Other characteristics and advantages of the present invention will become clearer from the following detailed description of an embodiment of the present invention, illustrated as a non-limiting example in the attached figures in which:

figure 1 shows a schematic representation of a pressing device provided with a compaction device;

Figure 2 shows the compaction device of Figure 1 in a different operating configuration; - figure 3 shows a top view of the device of figures 1 and 2;

Figures 4 and 5 show two different operating stages of the compacting device shown in Figure 3;

figure 6 shows a schematic representation, in top view, of a different embodiment of the compacting device;

figure 7 shows a sectional view according to plane VII-VII of figures 4 and 6;

The pressing device is provided with a conveyor belt (T) that can move along a main direction (X), for the forward movement of a load (S) of incoherent ceramic material to be pressed. A press (P) is arranged along the conveyor belt (T) to receive the load (S) carried by the conveyor belt (T). Both the belt (T) and the load (S) arranged on the belt (T) move between the two bearings of the press (P), so that the load (S) is pressed directly onto the belt (T).

For clarity, the following description specifies that "width" shall indicate a size measured in a horizontal plane perpendicular to the principal (X) direction, while "height" or "thickness" shall indicate a size measured along a direction vertical.

The compaction device comprises a first leveler (2), which is structured to come into contact with two lateral zones of the load (S) and push said lateral zones towards each other, perpendicular to the main direction (X).

The first leveler (2), in other words, compacts the load (S) perpendicular to the main direction (X), pushing its two lateral zones, which together are parallel to the main direction (X), towards each other. The incoherent material from the lateral areas of the load is collected, forming two stacks (As), basically parallel to the main direction (X), whose maximum level exceeds the level of the remaining areas of the load itself (S). Since the path of the pressing bearing is the same over the entire load (S), during pressing, the stacks in the lateral areas of the load (S), formed by the action of the first leveler (2), experience compaction which is considerably greater than that of the other areas of the load (S), and assume a material density equally greater than that of the other areas of the load (S). As is known, the presence of denser and more compact lateral zones considerably simplifies the removal and trimming of the incoherent material that is located outside the lateral zones, allowing to obtain precise and clear edges of the load (S).

In a possible embodiment, illustrated in figures 1 to 5, the first leveler (2) comprises a pair of side walls (21, 22) movable to move towards and away from each other along a horizontal direction, perpendicular to the main direction (X). In this embodiment, the intervention of the side walls (21, 22) is activated during a rest phase of the load (S), that is, during a stoppage of the conveyor belt (T). In essence, a load (S) is carried and stopped in an intermediate position with respect to the side walls (21, 22). Starting from a position of maximum mutual distance, in which they do not interfere with the load (S), the side walls (21, 22) are brought closer by means of actuators that are not illustrated in detail, for example pneumatic or hydraulic cylinders. When approaching to a position of minimum distance (figure 4), the side walls (21, 22) come into contact with the lateral zones of the load (S), creating the stacks described above of greater height. Once the compaction stage of the lateral zones of the load (S) is finished, the side walls (21,22) return to the position of maximum distance, so that the load (S) can move forward again and a new load (S) can be carried to the side walls (21, 22). The actuators that drive the side walls (21, 22) can advantageously be controlled remotely by means of a control module, for example to adapt the travel of the side walls (21, 22) to loads (S) of different sizes.

The side walls (21, 22) have a front surface, intended to come into contact with the load (S), which is arranged in a basically vertical position. For example, the side walls (21, 22) can be in the form of sheets or strips, arranged with the largest surface thereof vertical. The front surface of the side walls (21, 22) could also assume a different shape, for example convex or inclined.

In an alternative embodiment, shown in figure 6, the first leveler (2) comprises a pair of side walls (21, 22) arranged to converge with each other in a direction of advance of the load (S). In this way, the lateral zones of the load (S) come into contact with the side walls (21, 22), and are compacted, during the transport of the load (S). Preferably, the side walls (21, 22) remain fixed during the forward movement of the load (S). Each side wall (21, 22) comprises a front surface, directed towards the belt (T) and towards the other side wall, located above the belt (T), at a height to be able to come into contact with the load (S ). The height of the side walls (21, 22) can be adjusted with respect to the conveyor belt (T), to adapt the position of the side walls (21) to the thickness or height of the load (S). The position of the side walls (21, 22) can be adjusted along a horizontal direction perpendicular to the main direction (X), to allow the position of the side walls (21, 22) to be adapted to the width of the load (S ), in addition to adjusting the level of compaction in the lateral areas of the load (S), and therefore adjusting the height of the stacks that form in the lateral areas of the load (S). To adjust the position of the side walls (21, 22), it is possible to have motorized or manual regulators, depending on the ability of those skilled in the art. The use of motorized regulators allows the position of the side walls (21, 22) to be modified by means of remote controls, for example to adapt to loads (S) of different sizes.

In the embodiment shown in figure 6, the side walls (21, 22) are in the form of sheets or strips, arranged with the largest surface thereof in a basically vertical position.

The compaction device can also be provided with a second leveler (3), which is structured to come into contact with a front zone and a rear zone of the load (S) and push said zones towards each other, parallel to the main direction (X). The second leveler performs, in the front and rear areas of the load (S), the same action that the first leveler (2) performs in the lateral areas of the load (S).

After the intervention of the second leveler (3), the inconsistent material is collected from the front and rear areas of the load, forming two stacks (Af, Ar), basically perpendicular to the main direction (X), whose maximum level exceeds the level of the remaining areas of the load itself (S).

After the intervention of the first and second levelers (2, 3), the load (S) then has a basically rectangular perimeter area, comprising a stack (As, Af, Ar) of incoherent material whose maximum level exceeds the level of the remaining areas of the load itself (S). During pressing, both the stacks in the front and rear areas of the load (S), formed due to the action of the second leveler (3), and the stacks formed in the lateral zones of the load (S), formed due to the action of the first leveler (2), experience a compaction that is considerably greater than that of the other zones of the load (S), assuming an equally higher material density than that of the other areas of the load (S). In this way, at the end of pressing, the load (S) comprises a closed perimeter zone, which follows the entire edge of the load (S) itself, in which the incoherent material has greater compaction and material density. This makes it easier and more precise to trim the entire edge of the load (S).

Preferably, the second leveler (3) can move along a vertical direction between a lower position (figure 1), in which it can come into contact with a load (S), and an upper position (figure 2), in the one that does not interfere with the load (S). In the upper position (figure 2), the second leveler (3) allows the transit of the load (S) on the surface of the conveyor (T). Known-type actuators, not illustrated in detail, are arranged to allow the vertical movement of the second leveler (3).

In the illustrated embodiment, the second leveler (3) comprises a pair of side walls (31, 32) that can move towards and away from each other, parallel to the main direction (X). Preferably, but not exclusively, the side walls (31, 32) have a front surface, intended to come into contact with the load (S), which is arranged in a substantially vertical position. For example, the side walls (31, 32) may be in the form of sheets or strips, arranged with the largest surface thereof vertical. Actuators that are within the ability of those skilled in the art can be used to actuate the sidewalls (31, 32). Said actuators can advantageously be controlled remotely by means of a control module, for example to adapt the travel of the side walls (31, 32) to loads (S) of different sizes.

The intervention of the side walls (31, 32) is activated during a rest phase of the load (S), or during a stoppage of the conveyor belt (T). Starting from a configuration in which the second leveler (3), and the side walls (31, 32), are located in the upper position, a load (S) can be transported and stop in an area between the side walls (31, 32). Subsequently, the second leveler (3) moves to its lower position (figure 2), in which the side walls (31, 32) can come into contact with the load (S). Starting from a position of maximum mutual distance, in which they do not interfere with the load (S), the side walls (31, 32) are brought closer to each other by means of actuators not illustrated in detail, for example pneumatic or hydraulic cylinders. By approaching each other to a position of minimum distance (figure 5), the side walls (31, 32) come into contact with the front and rear areas of the load (S), creating the stacks of greater height described above. Once the compaction stage of the front and rear areas of the load (S) is finished, the side walls (31, 32) return to the position of maximum distance and rise towards the upper position, so that the load (S ) can move forward again and a new load (S) can be brought to the side walls (31, 32).

In the embodiment shown in figures 1 and 2, also the first leveler (2) can move along a vertical direction between a lower position (figure 2), in which it can come into contact with a load (S), and an upper position (figure 1), in which it does not interfere with the load (S). Preferably, the first leveler (2), in the embodiment comprising the side walls (21, 22), can be associated with the second leveler (3) to form an integral group with respect to vertical displacement. In this embodiment, the intervention of the two levelers (2, 3) is triggered during a stoppage of the conveyor belt (T). The two levelers, which are initially in the upper position, are lowered to the lower position. In such a position, each successively performs its own compaction path. Once the compaction paths have been completed, the two levelers (2, 3) return to their upper position and the conveyor belt (T) moves forward again towards the press (P).

In a variant of the embodiment shown, the first leveler (2) could also not be integral with the second leveler (3) with respect to vertical displacement. This occurs because the second leveler (2) does not obstruct the forward movement of the load (S) when the side walls (21, 22) are located in a widened position. Therefore, the second leveler (2), during the operation of the pressing device, could always remain in the lower position, and be raised, for example, to carry out maintenance operations.

The pressing device is particularly effective when the conveyor belt (T) assumes a continuous configuration, or in a configuration in which it comprises a first part (T1) and a second part (T2), consecutive to each other, which can move independently of each other. one from the other. In both cases, a feeding device (F) is arranged along an initial part of the conveyor belt (T). If the conveyor belt (T) comprises the two parts (T1, T2), the feeding device (F) is arranged along the first part (T1) to deposit a load (S) on the first part (T1). ). The feeding device (F) is, for example, in the form of a hopper provided with a lower discharge opening.

The feeding device (F) operates in the first part (T1), that is, the loads (S) are deposited in the first part (T1).

The front end of the first part (T1) is at least partially above a rear end of the second part (T2), at a slightly higher height than the second part (T2). By driving the first and second parts (T1, T2) synchronously forward, i.e. at the same speed of forward movement, the load (S) is transferred from the first part (T1) to the second part ( T2) performing a small jump down at the front end of the first part (T1).

The presence of first and second parts (T1, T2), independent of each other, makes it possible to manage the intervention of the compaction device with considerable flexibility. In particular, while the second part stops, to allow the compaction device to intervene, or to allow the press (P) to intervene, the first part (T1) can be actuated to move forward to allow the deposition of a load (S ). The step of depositing a load (S) can be synchronized with the intervention of the compaction device, so that it ends before or simultaneously with the intervention of the compaction device. In this way, once the intervention of the compaction device is finished, the first and second parts (T1, T2) can be actuated forward to carry out the transfer of the load (S) deposited on the first part, and to simultaneously transfer the load (S) that has undergone compaction towards the press (P).

If the conveyor belt (T) comprises the first and second parts (T1, T2) that can move independently of each other, it is possible to form the stacks (Af, Ar) in the front and rear areas of the load by modifying the speed of the forward movement of the two parts, so that, during the transfer of the front zone and the rear zone of the load (S) from the first part to the second part, there is a reduction in the speed of the movement of load advance. This causes the formation of the stacks (Af, Ar). For example, while the forward zone of the load (S) passes from the first part (T1) to the second part (T2), it is possible to increase the speed of the first part (T1) with respect to the second part (T2) and/or reduce the speed of the second part (T2) relative to the speed of the first part (T1). In this way, it is possible to obtain the stacking (Af) in the front area, without requiring the second leveler (3). In the same way, it is possible to obtain the stacking (Ar) in the rear area of the load (S), increasing the speed of the first part (T1) with respect to the second part (T2), and/or reducing the speed of the second part (T2) with respect to the speed of the first part (T1).

The pressing device allows to obtain important advantages. In the first place, the compaction device allows loads (S) to be reached with a perimeter zone of greater material density, without having pressing bearings provided with protruding edges or frames. This makes it possible to reduce the cost of the pressing bearings and simultaneously reduce the adaptation times with a change in the size of the loads (S) to be pressed. Indeed, it suffices to modify the path and/or the mutual distance of the side walls (21, 22, 31, 32) to be able to reach the stacks (As, Af, Ar) in loads (S) of different sizes. In fact, changes in the size of loads (S) can be managed without having to stop the pressing line to carry out adaptation interventions; on the contrary, it will suffice to simply adjust the path or the mutual distance between the side walls (21, 22, 31, 32). Such adjustment can occur by means of remote controls on the set of actuators to actuate the side walls themselves, or on suitable regulators that can be arranged for the levelers (2, 3).

Claims (2)

1. A method for pressing ceramic articles, comprising the following steps: depositing a load (S) of incoherent material on a conveyor belt (T); transporting the load (S) along a main direction (X); by means of a first leveler (2), push two lateral zones of the load (S) towards each other, perpendicular to the main direction (X), to form two stacks (As), basically parallel to the main direction (X), whose maximum level exceeds the level of the remaining areas of the charge (S); characterized by moving both the belt (T) and the load (S) arranged on the belt (T) between two pressing bearings of the press (P) and pressing the load (S) directly on the conveyor belt (T) after the formation of stacks (As). 2. The method according to claim 1, wherein, before pressing the load (S), a step is provided to push a front area and a rear area of the load (S), parallel to the main direction (X ), towards each other by means of a second leveler (3), to form two stacks (Af, Ar) that are basically perpendicular to the main direction (X), whose maximum level exceeds the level of the remaining areas of the load ( S).