Apparatus for forming tiles

Abstract

 An apparatus for depositing a flowable material on a support (3) comprises flexible screen means (14) provided with openings (16) to enable said flowable material to move through said openings (16) and winding means (18) arranged to wind onto, and unwind from, an external portion of said screen means (14), said winding means (18) being provided with dragging means (36) arranged to control the operation of said winding means (18).

Description

[0001] The invention concerns an apparatus for forming tiles by pressing ceramic powders and, more in particular, for forming tiles consisting of a base layer and of a decorative material distributed on the base layer.

[0002] Italian patent application No. MO99A000141 describes an apparatus for forming tiles, comprising transfer means provided with cells opened on the upper and on the lower part for being filled with base ceramic material and for pouring said base ceramic material between into cavities of a ceramic mould, and flexible screen means provided with openings through which flowable decorative material can pass, the screen means being supported by winding means to said transfer means.

[0003] The screen means comprises a foil that is operated by a shaft on which a pair of wheels is fitted, which wheels are peripherally provided with dragging pins that engage in holes made in side strips of said foil.

[0004] The ends of the foil are coupled with support rollers with which said winding means are provided. Said support rollers are rotatably coupled to the transfer means and are forced to rotate by return springs. During operation, at each feed cycle of the mould cavities, the foil unwinds from one of the said support rollers and winds around the other support roller, or vice versa, at each passage happens that the foil's openings pass underneath the containing means of the decorative material and the foil's opening promote of particles of decorative material the outflow from the containing means.

[0005] Said return springs make the rollers to rotate in opposite directions: in this way the foil is kept taut in contact with a delivery section of before said containing means.

[0006] In order to correctly perform the above-described functions, the springs are initially properly pre-loaded.

[0007] During the working phases, the foil unwinds from a first roller of said support rollers to wind on a second roller of said support rollers, in consequence of this, the spring associated to the second roller is partially unloaded in relation to the initial pre-loading, whilst the spring associated to the first roller is further loaded.

[0008] One drawback of the apparatus described above consists in the fact that, the springs associated to the winding means are particularly subject to breakage's risks due to the cyclical load variations to which they are subjected.

[0009] Said load variations, moreover, arrange that the springs do not work constantly but that the spring perform a traction action towards the film that varies with the deviation from the initial pre-loading conditions.

[0010] Since, as described above, the film is withdrawn by the spring with forces of non-constant intensity, the holes obtained on the edges of the foil shift in relation to the position of the pins that are arranged to engage in them, with consequent deterioration of the foil near said holes and said holes risk to flange.

[0011] This drawback is magnified when the foil is made of a material with limited mechanical resistance, such as for example, of an elastomeric material.

[0012] One purpose of the present invention is to improve the apparatuses for forming ceramic products.

[0013] Another purpose of the invention is to obtain an apparatus for forming ceramic products that is provided with decorative means with flexible screen said decorative means being substantially little subject to wear and to the breakage's risks.

[0014] A further purpose of the invention is to obtain an apparatus for forming ceramic products provided with decorative means with flexible screen, which is not damaged by the interaction with relative actuating means.

[0015] Yet another further purpose is to obtain an apparatus for forming ceramic products provided with winding means provided with elastic means that is subjected to substantially constant stress.

[0016] According to the invention, an apparatus is provided for depositing a flowable material on a support, comprising flexible screen means provided with openings through which said flowable material can pass through and winding means suitable for winding on and unwinding from an external portion of said winding means said screen means, characterised in that said winding means comprises dragging means suitable for checking the operation of said winding means.

[0017] In one advantageous embodiment, the winding means comprises first roller means from which the screen means is unwound and second roller means on which the screen means is rewound, or vice versa.

[0018] In another advantageous embodiment, the dragging means comprises first toothed wheel means associated to the first roller means, and second toothed wheel means associated to the second roller means, the first toothed wheel means and the second toothed wheel means being interconnected by a third toothed wheel means that engages simultaneously with the first toothed wheel means and the second toothed wheel means.

[0019] Advantageously, the first toothed wheel means and the second toothed wheel means actuate the rotation of the first roller means and of the second roller means, respectively, in a synchronous manner and in the same direction.

[0020] In a further advantageous embodiment, between the first roller means and the first toothed wheels means and between the second roller means and the second toothed wheel means, respectively, elastic means is interposed, that is arranged to stretch the screen means between the first roller means and the second roller means.

[0021] In a yet further advantageous embodiment, said support is a ceramic product, particularly a ceramic tile.

[0022] Owing to the invention, can be obtained an apparatus for forming ceramic supports decorated by screen means in which first roller means and second roller means, onto and from which the screen means is wound and unwound, are mechanically actuated so as to rotate at a speed that is synchronised with the feed speed of the screen means.

[0023] In this manner, the elastic means performs the sole task of stretching the screen means between the roller means and does not, as is the case with prior-art apparatuses, cause the screen means to be wound onto the roller means.

[0024] The elastic means, therefore, at the moment of assembly, is subjected to pre-loading that remains substantially unaltered during the entire operation cycle, said pre-loading being necessary only to stretch the screen means.

[0025] The elastic means comprises first spring means fixed to the first toothed wheel means and second spring means fixed to the second toothed wheel means.

[0026] Therefore, during operation, the first spring means and the second spring means rotate synchronously: this means that substantially they are not subjected to additional tensions, with respect to the tension generated by the initial pre-load. Owing to this aspect of the invention, therefore, the screen means is not subjected to deviations, not even slight deviations, from its correct work position, therefore, being little subject to wear and to the damage's risks caused by imprecise interaction with the respective actuating means.

[0027] The invention can be better understood and implemented with reference to the attached drawings that illustrate by way of example only and not of limitation, one embodiment of the invention, wherein:

Figure 1 is a schematic cross section view taken along a vertical plane of the apparatus according to the invention;

Figure 2 is a top view of the apparatus of Figure 1 wherein is schematically shown dragging means of the winding means;

Figure 3 is a front view of the dragging means of Figure 2;

Figure 4 is a cross section view along a diverted plane IV-IV of Figure 3.

[0028] As shown in Figure 1, an apparatus 1 for feeding a ceramic press 2 to form ceramic products, such as, for example, iles 3, comprises transfer means 4 arranged to feed cavities 5 of a mould 6 of the press 2, with loose ceramic material, said loose ceramic material comprising a base material suitable for constituting a body of the tiles 3 to be formed and a decorative material arranged for forming an ornamental motif on the visible face of said tiles 3. The transfer means 4 comprises a movable feed carriage 6 that moves alternately between a rear position in which it receives the base material from a hopper 7 and an advanced position into which it pours said base material into the cavities 5. At the front, the carriage 6 bears a pusher 8 that pushes the tiles 3, that have been already formed and expelled from the cavities 5 towards an evacuation line 9 and comprises a grill 10 defining a plurality of cells arranged to contain the base material during the transfer. Between the grill 10 and the front area of the carriage 6 that holds the pusher 8, on the side of the carriage 6, is provided a container 11 into which the decorative material is poured from a further hopper 12, fixed and arranged in such a way as to be above the container 11 when the carriage 6 is in its loading position of the grill 10, in other words the carriage 6 being with the grill 10 arranged below the hopper 7.

[0029] The container 11 can be divided between many non-communicating compartments, or it can be replaced by a plurality of independent containers, each one of the containers being arranged to contain a decorative material having a particular colouring and/or granulometry.

[0030] In this way it is possible to create polychrome decorations whilst maintaining an optimal control of the distribution of the decorative materials.

[0031] As shown in Figure 3, the container 11 is provided with a body 33 constituted by a tubular element 34 provided at the bottom with an outlet 35 located at the lowest point of the container 11, the latter having externally a rounded profile on which screen means 14 is wound.

[0032] Inside the body 33 is inserted a shutter 30 comprising a further tubular element 31, that is coaxial with the tubular element 34, and that can be operated to rotate around its own longitudinal axis by means of a pneumatic actuator that is not shown.

[0033] The shutter 31 is provided with a further outlet 32 which, in a delivery position, in which it is aligned on the outlet 35, enables the decorative material to come out from the container 11 to interact with the screen means 14. When the shutter 30 is rotated, the further tubular element 31 shuts the opening 12, thereby preventing the transfer of the decorative material through said opening 12 and enabling the transfer of the screen means 14 without undesired outflows of decorative material from the container 11 occurring.

[0034] As shown in Figure 2, the screen means 14 comprises a foil 15, in which openings 16 are created, which consist, for example, of a plurality of through microholes that define a decorative motif 17 to be placed on the visible face of the tiles 3 to be formed. The foil 15 therefore constitutes a controlling means for the outflow of the decorative material from the outlet 35.

[0035] The decorative motif 17 may be formed by a plurality of drawings or incisions, equal or different, that corresponds to the plurality of cavities 5 of the mould 6 of the press 2.

[0036] The apparatus is also provided with winding means 18 comprising a first support roller 18a to which a first end of the foil 15 is associated and a second support roller 18b to which a second end of the foil 15 is associated.

[0037] Dragging means 36 are also provided that are arranged to control the operation of the winding means 18.

[0038] The dragging means 36 comprises toothed wheel means 37 rotatably coupled, by means of ball bearings 38, to a lateral portion 6a of the carriage means 6.

[0039] The toothed wheel means 37 comprises a first toothed wheel means 39 made integral, by a first key 40, to a relative first pin 41, and a second toothed wheel 42 made integral, by a second key 43, to a relative second pin 44.

[0040] Between the first pin 41 and the first support roller 18a a spring 45 is interposed, whilst, similarly, a second spring 46 is interposed between the second pin 44 and the second support roller 18b, each of said springs 45, 46, being, for example of a helicoid type and having a first end 45a, 46a connected to a relative appendix 47, 48 of the first pin 41, or of the second pin 44, respectively, and a second end 45b, 46b fixed to the first support roller 18a, or to the second support roller 18b, respectively.

[0041] The dragging means furthermore comprises a third toothed wheel 49 interposed between the first toothed wheel 39 and the second toothed wheel 42 and engaging with the first toothed wheel 39 and the second toothed wheel 42.

[0042] Advantageously, the first toothed wheel and the second toothed wheel are the same as one another; the first support roller 18a and the second support roller 18b therefore, rotate at the same speed, thereby enabling the foil 15 to be unwound from the first support roller 18a and be simultaneously rewound onto the second support roller 18b, or vice versa.

[0043] The first spring 45 and the second spring 46 are properly pre-loaded during the assembly phase so as to stretch the foil 15 and to enable a correct sliding of the same on the tubular element 34 in order to regulate the outflow from the container 11 of the decorative material

[0044] During the operation, the first spring 45 and the second spring 46, being integral, respectively, to the first toothed wheel 39 and to the second toothed wheel 42, rotate simultaneously and are, therefore, not substantially stressed beyond the initial pre-load.

[0045] The apparatus 1 furthermore comprises actuating means 19 arranged for moving the foil 15: during the operation, in fact, the foil 15 unwinds from one of the support rollers, for example the second roller 18b, and winds onto the other support roller, for example the first roller 18a, or vice versa, in such a way that the openings 16 of the foil 15 pass underneath the outlet 35 and enable particles of decorative material to pass through them.

[0046] The actuating means 19 comprises a shaft 21 that passes through the container 11 and on which a pair of wheels 22 is fitted, which pair of wheels 22 is peripherally provided with dragging pins 23 engaging in holes 24 made in lateral strips of the foil 15.

[0047] The pins 23 may have a rounded free end and they can be withdrawn inside the wheels 22: in each of said wheels 22, in fact, it is possible to obtain a plurality of seats arranged for receiving the above said pins 23, in a position in which they do not interfere with the holes 24.

[0048] During operation, the wheels 22 actuate the foil 15, causing it to be unwound from one of the winding means 18, for example, from the second roller 18b, and in consequence the wheels 22 cause the second toothed wheel 42, associated to said winding means 18, to rotate. The toothed wheel 42, in turn actuates, by means of the third toothed wheel 49, the first toothed wheel 39: the first roller 18a, is thus made to rotate and receives on itself the portion of the foil 15 that has been unwound from the second roller 18b.

[0049] The winding of the foil 15 onto the first roller 18a is, therefore, obtained by making said first roller 18a to rotate by means of the dragging means 39 and not by means of a variation in the initial pre-load to which the first spring 45 was subjected.

[0050] In this way, it is possible to obtain an apparatus 1 provided with winding means with long operating life, because it is subjected to substantially constant stress and of a limited quantity.

[0051] Is furthermore obtained an apparatus 1, wherein the screen means 14 is subjected to uniform traction, this not only significantly limits wear, but also prevents that an imperfect positioning of the foil 15 generates interference between the holes 24 and the pins 23 and thereby causing breakages in the foil 15 itself.

[0052] Furthermore, as the errors of reciprocal positioning between the foil 15 and the winding means 18 are greatly reduced, or even eliminated, tiles 3 are obtained in which the decorative motifs are correctly positioned in relation to the base layer, which noticeably limits the production rejects and improves the apparatus's output.

Claims

1. Apparatus for depositing a flowable material on a support (3), comprising flexible screen means (14) provided with openings (16) to enable said flowable material to pass through said openings (16) and winding means (18) arranged for winding onto and unwinding from an external portion of said screen means (14), characterised in that said winding means (18) comprises dragging means (36) arranged for controlling the operation of said winding means (18).

2. Apparatus according to claim 1, wherein said winding means (18) comprises roller means (18a, 18b) rotatably supported on a frame (6) of said apparatus (1).

3. Apparatus according to claim 2, wherein said dragging means (36) comprises toothed wheel means (37) associated to said roller means (18a, 18b).

4. Apparatus according to claim 3, wherein said toothed wheel means (37) comprises a first toothed wheel (39) associated to first roller means (18a) of said roller means and a second toothed wheel (42) associated to second roller means (18b) of said roller means, said toothed wheel means (37) being suitable for synchronising the rotation of said first roller means (18a) and of said second roller means (18b).

5. Apparatus according to claim 4, wherein between said first toothed wheel (39) and second toothed wheel (42) a third toothed wheel (49) is interposed, that meshes with said first toothed wheel (39) and with said second toothed wheel (42).

6. Apparatus according to any one of the claims 3 to 5, wherein said toothed wheel means (37) and said roller means (18) are interconnected by elastic means (45, 46) arranged for stretching said screen means (14) between said roller means (18).

7. Apparatus according to claim 6, wherein said elastic means (45, 46) is assembled on said toothed wheel means (37) and on said roller means (18) in such a way that they are subjected to pre-loading tension of a preset amount.

8. Apparatus according to claim 6, or 7, when appended to claim 4, or to claim 5, wherein said elastic means comprises a first spring (45) interposed between said first toothed wheel (39) and said first roller means (18a) and a second spring interposed between said second toothed wheel (42) and said second roller means (18b).

9. Apparatus according to any one of the preceding claims, and further comprising actuating means (19) provided with guide shaft means (21) suitable for moving said screen means (14).

10. Apparatus according to claim 9, wherein to said guide shaft means (21) is associated dragging wheel means (22) provided with pin means (23) protruding from the external surface of said dragging wheel means (22) to engage in holes (24) obtained in end zones of said screen means (14).

11. Apparatus according to claim 9, or 10, when appended to claim 4, or 5, or to any one of the claims 6 to 8 when appended to claim 4, or 5, wherein said guide shaft means (21) unwinds said screen means (14) from said first roller means (18a) to direct it towards said second roller means (18b), or vice versa.

12. Apparatus according to any one of the claims 9 to 11, wherein said guide shaft means (21) actuates said screen means (14) to pass underneath outlet means (12) of containing means (11) of said flowable material.

13. Apparatus according to claim 12, and further comprising shutter means (30) arranged for preventing said flowable material to pass through said outlet means (12).

14. Apparatus according to claim 12, or 13, wherein said containing means (11) comprises a tubular element (34) onto the outer surface of which, said screen means (14) winds.

15. Apparatus according to claim 14, when appended to claim 13, wherein said shutter means comprises a further tubular element (31) arranged inside said tubular element (34) coaxially with said tubular element (34) and provided with further opening means (32).

16. Apparatus according to claim 15, wherein said further tubular element (31) is movable and rotates around its own longitudinal axis in order to transfer said further opening means (32) from a delivery position in which said further opening means (32) is aligned with said opening means (12) to a closing position in which said further opening means (32) faces a continuous zone of said tubular element (34).

17. Apparatus according to any one of the preceding claims, wherein said support comprises a ceramic product (3).

18. Apparatus according to claim 17, wherein said flowable material comprises a decorative material suitable for decorating a visible face of said ceramic product (3).

Drawing