Rotary press for producing tiles, having two stations for loading the material into the mould

Abstract

 The rotary press for producing tiles comprises: a turntable (3) that carries a plurality of moulds (5); around the said turntable (3), a first (7) and a second (9) mould-loading station. The second loading station (9) comprises a loading container (27) that receives the loose material from a hopper (15) and discharges it into an intermediate container (13) located above the mould (5); and shut-off means (55) that close and open the bottom of the intermediate container (13). A movable unit in the second station comprises the loading container (27) and the shut-off means (55), the latter moving integrally with the loading container.

Description

Technical field

[0001] The present invention relates to a rotary press for producing tiles and similar articles, of the type comprising: a turntable on which are placed several moulds which are to be filled with loose material that is then pressed and consolidated; and, located around the turntable, two loading stations which introduce, one after the other, a first layer of loose material and a second layer of loose material into each mould, the second layer of loose material being different from the first in terms of both type and thickness.

State of the art

[0002] Rotary presses do currently exist of the type referred to in the present invention, in which two successive loading stations introduce two loads of loose material directly into the mould to form a first layer (which in the finished tile will form the surface to be walked on) and a second layer (which in the finished tile will form the back or bottom surface). The thickness of the two layers is usually different: whereas the thickness of the first layer can be adjusted as desired by pouring a greater or lesser amount of loose material into the mould, in this type of machine, the thickness of the second layer necessarily needs to be equal to the difference between the total height of the mould and the thickness of the first layer. This limits the versatility of the machine.

[0003] In addition, these machines have the drawback that the loose material is not distributed evenly in the mould on account of the action of the scraper which passes over the upper surface of the mould in the final stage of the loading operation.

[0004] In order to overcome these drawbacks, machines have been designed in which the second layer of loose material is not loaded directly into the mould but into an intermediate container fitted with a system of shutters which allow the loose material subsequently to drop from the intermediate container into the mould.

[0005] Machines of this second type are currently known, but have the disadvantage that the shut-off systems are extremely complex and typically consist of a system of continuous belts which are subject to wear by the granular material which is usually employed in the production of tiles.

Summary of the invention

[0006] The object of the present invention is to produce a rotary press of the type referred to above, with an intermediate container into which the second layer of loose material is loaded, but which does not have the drawbacks of conventional machines.

[0007] This and further objects and advantages, which will be clear to those skilled in the art on reading the following description, are achieved with a machine in which the second loading station has a movable unit comprising: an intermediate loading container, in which the loose material which is to form the second layer in the mould is accumulated, and the shut-off means of the intermediate container, which move integrally with the loading container when the movable unit moves from a position outside the turntable and underneath a hopper containing the loose material, to the position above the turntable in which the loose material is passed from the loading container - into which it has been fed from the hopper - into the intermediate container. The forward travel of the movable unit causes the closure of the bottom of the intermediate container, while the subsequent return travel of the movable unit gradually uncovers the bottom of the intermediate container, thereby enabling the loose material to be discharged from the intermediate container into the mould which has been brought beneath the said intermediate container by the rotating turntable.

[0008] This structure retains the same advantages as conventional machines whilst at the same time doing away with all the complex mechanisms required to move the shutters and eliminating or substantially reducing the problems caused by wear on conventional shutters consisting of continuous belts. The end result is a machine which is more cost-effective, more reliable and has a very high production rate.

[0009] Further advantageous characteristics of the press according to the invention will be illustrated in detail in the description of a possible embodiment and are referred to in the appended claims.

Brief description of the drawings

[0010] The invention will be understood more clearly by following the description and the appended drawing, which shows a possible nonlimiting embodiment of the invention. In particular, in the drawing:

Fig. 1 shows a diagrammatic plan view of a rotary press; and

Fig. 2 shows a cross-section on a longitudinal vertical plane of the second loading station.

Detailed description of a preferred embodiment of the invention

[0011] Fig. 1 shows, in a very diagrammatic manner, a rotary press, of a type known per se, in which the second loading station can be made in accordance with the details described in the present invention. The press as a whole is denoted by the reference 1 and has a turntable 3 that rotates in the direction indicated by the arrow f3 about a vertical axis A-A. A plurality of moulds 5 are located on the turntable and are successively carried through the various working stations found along the rotary path travelled by the turntable 3. Of these stations, the reference 7 denotes a first station in which a first layer of material (usually with a high moisture content) is loaded into each mould 5, while the reference 9 denotes a second station in which a second layer of loose material is loaded into the moulds which have already been partially filled in the station 7. The reference 10 denotes the pressing station and the reference 11 denotes the collection station.

[0012] The structure of the station 9, which forms the subject of the present invention, will be described in detail below.

[0013] Fig. 2 shows a longitudinal cross-section on a plane II-II in Fig. 1. Fig. 2 also shows part of the turntable 3 and the mould 5, which is in the position in which the second layer of loose material is loaded into it. The mould 5 is a multiple mould for producing four tiles simultaneously. However, it should be understood that the mould can also be of a different shape.

[0014] Located above the mould 5, when it is in the station 9, is an intermediate container which is denoted as a whole by the reference 13 and consists of a plurality of compartments whose shape and position correspond to the compartments of the subjacent mould 5. The intermediate container 13 is loaded, in the manner described below, with the loose material which is to form the second layer of the tiles, a first layer of loose material, denoted by the letter S in Fig. 2, already having been dispensed into the mould 5.

[0015] The station 9 has a hopper 15 that contains a supply of loose material which is to form the second layer in the mould 5. The hopper 15 is carried by a stationary framework 17. The bottom 15A of the hopper opens out into an intermediate compartment 19. Located beneath the compartment 19 is a plate shutter 21 fitted with an upper wear sheet or plate 23. The plate shutter 21 has an aperture 25, the shape and size of which correspond to the lower aperture of the compartment 19. When the plate shutter 21 is in the position illustrated in Fig. 2, with its aperture 25 in line with the compartment 19, the latter communicates directly with a subjacent loading container 27 which can then be filled with the loose material contained in the hopper 15.

[0016] The loading container 27 is attached to the lower surface of the plate shutter 21. It has a lower aperture 27A, beneath which is located a stationary plate 29, to which the intermediate container 13 is attached. The stationary plate 29 is attached to the framework of the machine.

[0017] The plate shutter 21 is integral with a pair of guide runners, only one of which is visible in Fig. 2, where it is denoted by the reference 31. Each runner 31 is guided in a corresponding upper guide 33 which is integral with the framework 17.

[0018] The movement of the plate shutter 21, in the direction of the double arrow F, is obtained by means of a cylinder and piston actuator 35. The cylinder of the actuator 35 is attached at 37 to the framework 17, while the rod 39 of the actuator 35 is hinged at 41 to a block 43 which is integral with the plate shutter 21.

[0019] The plate shutter 21 is attached at the rear - by means of a bracket 45, a Silentbloc™ 47 and a crosspiece 49 - to a first sliding sleeve 50 mounted on a corresponding lower guide 51 constituted by a cylindrical bar, on which a second sliding sleeve 52 is also mounted. The two sliding sleeves 50 and 52 are joined together by an intermediate tube 53 which is coaxial with the cylindrical guide 51. On the actual machine, just as there are two upper guides 33, there are also two lower guides 51, a guide bar being provided on each side of the loading station.

[0020] Attached to the sliding sleeves 50, 52 is a shut-off means 55 that closes the bottom of the intermediate container 13 while it is being loaded by the loading container 27, in a manner which will be described below. The vertical position of the shut-off means 55 with respect to the lower guides 51, and therefore with respect to all the stationary elements of the loading station, can be adjusted via a screw system associated with each of the two sleeves 50, 52. The screw system provides a threaded bar 57 and a pair of ring nuts 59 and 61 for each sleeve 50, 52. The upper surface of the shut-off means 55 is formed by an interchangeable wear plate 63 which is locked in place by means of knobs 65.

[0021] The loading station which has been described up to this point works in the following way: in the position shown in Fig. 2, the loose material contained in the hopper 15 drops through the bottom 15A of the hopper and into the compartment 19, from which it then drops into the loading container 27, the bottom of which is closed by the stationary plate 29. When the mould 5 arrives underneath the intermediate container 13 in order to receive the second layer of loose material, the actuator 35 is activated so as to move the entire movable unit - made up of the plate shutter 21, the loading container 27 attached to the underside of the plate shutter 21 and the lower shut-off means 55 - towards the left, in the direction of the arrow F. The movement is guided along the upper guides 33 and the lower guides 51.

[0022] The front edge (on the left in Fig. 2) of the shut-off means 55, denoted by the reference 55A, lies ahead of the lower aperture 27A of the loading container 27 with respect to the direction of advance F of the movable unit. This means that when the unit moves in the direction F, it gradually closes the bottom of the intermediate container 13, starting from the right-hand edge and finishing with the left-hand edge, slightly in advance of the instant at which the loading container 27 arrives above the intermediate container 13. During this movement in the direction F, the said loading container 27 gradually drops its contents of loose material into the intermediate container 13. The latter is divided up into a series of subcompartments 13A by means of a plurality of partitions 13B that extend perpendicularly to the movement of the movable unit. An additional series of dividing partitions 13C are also provided, but are more sparsely spaced, in a direction parallel to the direction of advance F.

[0023] Once the actuator 35 has completed its travel, bringing the loading container 27 up to the left-hand edge of the intermediate container 13, its movement is reversed and the movable unit - comprising the plate shutter 21, the shut-off means 55 and the loading container 27 - is returned to the right (in the figure). This movement causes the gradual opening, from left to right, of the bottom of the intermediate container 13, thereby allowing the loose material, which has been emptied therein by the loading container 27, to drop into the mould. The dividing partitions 13B and, to a lesser degree, the dividing partitions 13C, enable the measure of loose material to be dispensed into the container 13 as evenly as possible, preventing an accumulation of material at the sides. This ensures that the second layer of loose material dropped into the subjacent mould 5 is of approximately even thickness.

[0024] In order to allow the shutters and loading containers to move easily, scrapers are provided in various positions and remove the loose material from the sliding surfaces. A first and a second scraper, denoted by the references 71 and 73, are provided on either side of the bottom 15A of the hopper and of the subjacent compartment 19. These scrapers remove the particles of loose material from the wear plate 23 of the plate shutter 21.

[0025] A third scraper 75 is located next to the loading container 27 and is in contact with the upper surface of the stationary plate 29 between the loading container 27 and the vertical axis of the turntable 3. This third scraper 75 is controlled by an actuator 77 that holds it in a raised position, in other words not in contact with the stationary plate 29, during the forward travel of the loading container 27 from the position shown in Fig. 2 to the position in which it lies above the intermediate container 13. During its return travel, the actuator 77 brings the scraper 75 into its lower position, that is in contact with the stationary plate 29 and with the upper surface of the intermediate container 13. In this way, the loose material in the intermediate container 13 is levelled off and any excess collects in the space between the scraper 75 and the loading container 27. This excess material will be pushed by the loading container 27 into the intermediate container 13 during the next passage of the movable unit.

[0026] A fourth scraper 79 is associated with the shut-off means 55 and cleans the upper surface of the wear plate 63 during the forward travel of the movable unit.

[0027] As can easily be seen, none of the scrapers pass over the material once it has dropped into the subjacent mould 5. The mould is thus loaded evenly, in contrast to conventional machines in which the second layer of material is loaded directly into the mould by the loading container without the use of an intermediate container.

[0028] The intermediate container 13 can be replaced with another one of different height depending on how thick the second layer of material in the mould 5 needs to be. If the intermediate container 13 is changed, the position of the shut-off means 55 with respect to the guide 51 also needs to be adjusted by means of the threaded bars 57, so that the distance between the lower aperture 27A of the loading container 27 and the upper surface of the wear plate 63 of the shut-off means 55 always approximately corresponds to the height of the intermediate container 13.

[0029] Needless to say, the drawing shows only one example which is given solely as a practical demonstration of the invention. It is of course possible to make changes to the said invention in terms of its forms and arrangements, without thereby departing from the scope of its underlying concept. Any reference numerals in the appended claims are intended to facilitate the reading of the claims with reference to the description and to the drawing and do not limit the scope of protection represented by the claims.

Claims

1. Rotary press for producing tiles, comprising: a turntable (3) that rotates about an axis (A-A) and carries a plurality of tile moulds (5); around the said turntable (3), a first mould-loading station (7), which loads a first layer of loose material into each mould, and a second loading station (9) which loads a second layer of loose material into each mould; the said second loading station (9) comprising a loading container (27) that receives the loose material from a hopper (15) and discharges it into an intermediate container (13) located above the mould (5); and shut-off means (55) that close and open the bottom of the intermediate container (13) in order to allow it to fill up and then discharge its contents into the subjacent mould; characterized in that the said second station (9) has a movable unit comprising the said loading container (27) and the said shut-off means (55), the latter moving integrally with the loading container, and the movable unit moving from a loading position beneath the said hopper (15) to a position in which its contents are discharged into the said intermediate container (13).

2. Press according to Claim 1, characterized in that the said movable unit moves in a radial direction with respect to the turntable.

3. Press according to Claim 1 or 2, characterized in that the said movable unit comprises an upper plate shutter (21), located between the outlet (15A) of the said hopper (15) and the loading container (27), to which the said shut-off means (55) are attached, the loading container (27) being located between the plate shutter (21) and the said shut-off means (55), and the distance between the outlet aperture (27A) of the loading container and that surface of the shut-off means which faces the latter being the same as the height of the intermediate container.

4. Press according to Claim 3, characterized in that the distance between the said shut-off means (55) and the said loading container (27) can be adjusted depending on the height of the intermediate container.

5. Press according to Claim 4, characterized in that the said intermediate container is interchangeable.

6. Press according to Claim 3, characterized in that the said plate shutter (21) interacts with a first and a second scraper (71, 73), located on either side of the outlet of the hopper (15).

7. Press according to Claim 3 or 6, characterized in that the said plate shutter (21) has a wear plate (23) that faces the hopper (15).

8. Press according to one or more of the preceding claims, characterized in that the said loading container (27) is associated with a third scraper (75) located on that side of the loading container that faces the axis (A-A) of the turntable (3).

9. Press according to Claim 8, characterized in that the said third scraper (75) is controlled by an actuator (77) that carries the scraper into the operating position during the return travel of the loading container (27), the third scraper being in a retracted position during the forward travel of the loading container.

10. Press according to one or more of the preceding claims, characterized in that the said shut-off means (55) interact with a fourth scraper (79).

11. Press according to one or more of the preceding claims, characterized in that the said shut-off means (55) have an upper wear plate (63).

12. Press according to Claim 3, characterized in that an elastic connection means (47) is located between the upper plate shutter (21) and the shut-off means (55).

13. Press according to one or more of the preceding claims, characterized in that the said movable unit is guided by a double system of guides comprising a pair of upper guides (33) and a pair of lower guides (51).

14. Press according to Claim 13, characterized in that, located between the said upper guides and the said lower guides, are actuator means (35) that control the movement of the movable unit.

15. Press according to Claim 13 or 14, characterized in that the said plate shutter (21) is rigidly guided along the upper guides (33) and the said shut-off means (55) are rigidly guided along the said lower guides (51).

16. Press according to Claim 15, characterized in that the said shut-off means are guided along each of the said lower guides by means of two sliding sleeves (50, 52) which are joined together by a tubular member (53).

17. Press according to one or more of the preceding claims, characterized in that the said intermediate container (13) is fitted with a series of dividing partitions (13B; 13C) that divide the internal volume of the said intermediate container (13) into a plurality of compartments (13A) or chambers.

18. Press according to Claim 17, characterized in that the said dividing partitions (13B) extend at least in a direction perpendicular to the direction of translation (F) of the said movable unit.

19. Press according to one or more of the preceding claims, characterized in that the said shut-off means (55) extend beyond the aperture (27A) of the loading container (27), so that they begin to close the bottom of the intermediate container (13) slightly in advance of the moment at which the loose material begins to be loaded and they delay the opening of the bottom of the container with respect to the outlet of the loading container (27) during the return travel of the said loading container.

Drawing