EP1088636A2

EP1088636A2 - Apparatus for deburring ceramic products, particularly glazed tiles

Info

Publication number: EP1088636A2
Application number: EP00120204A
Authority: EP
Inventors: Vasco Benassati
Original assignee: Individual
Current assignee: Individual
Priority date: 1999-09-28
Filing date: 2000-09-25
Publication date: 2001-04-04
Also published as: ITMO990204A0; ITMO990204A1; EP1088636A3; IT1310842B1

Abstract

An apparatus (1) for deburring ceramic products, particularly glazed tiles (P), advancing on a conveyance line (2), comprises a frame (3) for supporting means (4) for abrading the edges of the products, the means being arranged laterally to the line, and a tray for containing a fluid which is arranged below the abrading means, the abrading means being flexible, actuatable with respect to the products (P) and partially immersed in the tray (5).

Description

The present invention relates to an apparatus for deburring ceramic products, particularly glazed tiles.
In ceramics technology it is known that deburring consists in removing from the contour of ceramic products excess material which collects thereat during the different steps of production and treatment.
This material is constituted by the clayey mix that accumulates as burr at the edges of the products as a consequence of the molding process and/or, in the case of glazed products, by the glaze which, applied to their upper surface, drips and falls from their edges, covering them with layers of varying thickness.
It is therefore necessary to eliminate this excess material in order to obtain a finished product which has well-defined and smooth contours and is free from surface defects.
Moreover, in the case of glaze it is necessary to remove said glaze before the products are fired, in order to prevent the glaze from causing several pieces to stick together during firing, thus damaging the pieces and causing their rejection, and in order to prevent the glaze from depositing on the rollers that constitute the surface on which the products slide inside the kilns.
Conventional dry deburring units are constituted by one or more pairs of motorized abrasive wheels which are fixed opposite each other on the sides of the supporting frame of the line for conveying the ceramic products from the forming and/or glazing station towards subsequent decoration and/or firing stations.
The abrasive wheels arrange themselves laterally to two mutually opposite sides of the ceramic products that advance on the conveyance line; the distance that separates them can be adjusted manually according to the dimensions (width, length) of the size being manufactured, and once set, it is left unchanged until the production of that size ends.
The abrasive wheels rotate about axes which are parallel to the advancement direction of the products and in opposite directions which are orientated towards the center of the line; accordingly, they apply to the products a downward thrust whereby they scrape the excess material from the edges.
These units are not devoid of drawbacks, including the fact that since deburring is performed dry, it does not allow total removal of the excess material, and therefore the edges remain partially soiled. In addition it is necessary to reduce the distance between the abrasive wheels in order to increase the scraping action. Still further the higher pressure that they apply to the edges of the product, which is generally in the unfired state, easily causes edge chipping and breakage, with a consequent increase in defects and rejects.
It is also noted that the individual ceramic products of a particular size, even if they belong to a same production, hardly ever have identical dimensions (width, length), and that the opposite sides of a same product are hardly ever perfectly parallel to each other.
Accordingly, since the abrasive wheels are rigid and fixed at a specific distance, they do not allow to correctly deburr all the products: the ones that are larger with respect to the distance between the abrasive wheels are abraded excessively, to the point of compromising the quality of their surface and their integrity, while the ones that are smaller are abraded only partially and excess material remains on their edges.
Finally, due to the above reasons of rigidity of the abrasive wheels and "invariance" of their distance, these deburring units do not allow to clean the uneven, undulated and contoured edges that characterize particular ceramic products, such as for example rustic-effect tiles or tiles which simulate natural stone, and they do not allow to deburr profiled elements having, for example, a toroidal shape.
As an alternative to abrasive wheels, conventional wet deburring units comprise one or more pairs of packs of disks of rubber or other material, which replace the abrasive wheels, but whose fixing and operating principles are substantially identical.
The disks are of the water-bath type and during work they wet the excess material that has accumulated on the edges of the ceramic products, softening it and making it easier to remove.
Nonetheless, these wet deburring units only partially solve the problems related to the abrasive wheels; the disks are in fact rigid (or are such as to undergo only slight elastic deformations) and are fixed at an invariant distance, do not allow to correctly deburr all the pieces of a same production run having sides which are not perfectly parallel and/or having non-constant dimensions, and are unable to remove material from undulated, contoured and irregular edges.
Another disadvantage related to conventional types of abrasive wheel and disk is that they are arranged at a distance which is smaller than the width of the products, so that taking into account their gradual wear they can operate for a sufficiently long time without having to intervene with frequent operations for adjusting their distance.
However, this forces a frequent replacement of the abrasive wheels or disks due to their excessive wear during the first period of deburring, and this entails considerable consumption of material and high maintenance costs.
The aim of the present invention is to eliminate the above-noted drawbacks of conventional types of deburring unit by providing an apparatus for deburring ceramic products, particularly glazed tiles, which allows to totally and easily eliminate the excess material, regardless of the shape of the products or of their edges, does not require particular and frequent adjustment and setup operations, and allows to perfectly deburr the contour of all the products of a same production run regardless of any size variations between individual tiles and of any lack of parallelism of the sides.
Within the scope of this aim, an object of the present invention is to achieve the above aim with a structure which is simple, relatively easy to provide in practice, safe in use, effective in operation, and relatively low in cost.
This object and others are achieved by the present apparatus for deburring ceramic products, particularly glazed tiles, advancing on a conveyance line, characterized in that it comprises a frame for supporting means for abrading the edges of said products, said means being arranged laterally to said line, and a tray for containing water or the like which is arranged below said abrading means, said abrading means being flexible, actuatable with respect to said products and partially immersed in said tray.
Further characteristics and advantages of the present invention will become better apparent from the following detailed description of a preferred but not exclusive embodiment of an apparatus for deburring ceramic products, particularly glazed tiles, illustrated only by way of non-limitative example in the accompanying drawings, wherein:
Figure 1 is a perspective view of an apparatus for deburring ceramic products, particularly glazed tiles, according to the invention;
Figure 2 is an enlarged-scale lateral perspective view of the apparatus of Figure 1;
Figure 3 is a perspective view of a portion of the apparatus according to the invention;
Figure 4 is a partially sectional schematic front view of the apparatus according to the invention.
Figure 5 is a perspective view of a portion of a first alternative embodiment of the apparatus according to the invention;
Figure 6 is a partially sectional schematic front view of the apparatus of Figure 5;
Figure 7 is a perspective view of a portion of a second alternative embodiment of the apparatus according to the invention;
Figure 8 is a partially sectional schematic front view of the apparatus of Figure 7;
Figure 9 is a schematic top view of a possible application of the apparatus of Figure 7.
With reference to the above figures, the reference numeral 1 generally designates an apparatus for deburring ceramic products, particularly glazes tiles.
In the above figures, the apparatus 1 is shown in a possible application in which it is associated with a line 2 for conveying glazed tiles P.
The tiles P are transferred from a glazing station to a subsequent treatment station, both of which are not shown herein.
The apparatus 1 is constituted by a frame 3 which, in the illustrated embodiment, coincides with the supporting frame of the line 2, which supports two abrading means 4, arranged at the opposite sides of the line 2, and a fluid containment tray 5, which is arranged below the abrading means 4. The fluid is preferably water.
The abrading means 4 flank two mutually opposite edges of the tiles P and are actuated with a relative motion with respect to the direction of advancement of the tiles P on the line 2, as a consequence of which they remove from the respective edges the excess material (glaze) which has deposited thereon in the preceding treatment station (glazing station).
Conveniently, the abrading means 4 are flexible and are partially immersed in the tray 5.
The abrading means 4 are constituted by a support 6 which supports two drums 7 which are superimposed one another and able to rotate and on which multiple belts 8, closed in a loop, are wound.
Advantageously, the drums 7 have cylindrical surfaces 9 provided with slots for accommodating the belts 8.
The supports 6 support means 10 for motorizing the pairs of drums 7; said means are arranged at the top of the supports 6 in order to prevent them from making contact with the water and/or from being soiled by the glaze.
The drums 7 are turned about their axes and thus move the belts 8, which are placed and kept in contact with the edges of the tile P and remove the excess material from them.
In order to allow this abrasion operation and render it effective, the axes of the drums 7 must not be parallel to the direction of advancement of the tiles P.
Moreover, the directions of rotation of the two pairs of drums 7, arranged at the two sides of the line 2, must be mutually opposite and directed towards the center of said line 2; in this way, the belts 8 apply to the tile P a downward thrust, keeping it stable on the line 2.
Since the belts 8 are partially immersed in the tray 5, they entrain part of the water with which they wet the excess material on the edges of the tiles P, facilitating its removal.
The belts 8 are made of flexible material, such as elastomers and rubber, obtained by drawing or extrusion, and have a substantially circular transverse cross-section.
The abrading means 4 are partially covered by protective screens 11 which are fixed to the supports 6.
Respective abutment plates 12 are fixed to the supports 6 and are arranged proximate to the active portions of the belts 8, i.e. proximate to the portions that are in contact with the tiles P, and on the opposite side with respect to them.
In a first alternative embodiment, the plates 12 are fixed to the supports 6 so as to adhere to the belts 8, which are thus kept in contact with the edges of the tiles P.
In this way, the belts 8 partly lose their transverse elasticity and apply more pressure to the edges of the tiles, being able to remove even the hardest material from them.
In a second alternative embodiment, the plates 12 are fixed to the supports 6 proximate to the belts 8 and at gradually increasing distances with respect to them; the belts 8 thus gradually regain their transverse elasticity.
In these last operating configurations, the belts 8, thanks to their deformability, follow the edges of the tiles P without applying thereto intense pressures yet remove the excess material completely.
The apparatus 1 is further provided with adjustable water absorption means 13 which are associated with the supports 6 and are designed for adjusting the amount of water entrained by the belts 8 and simultaneously removing from them the material that they have removed from the edges of the tiles P.
The absorption means 13 are constituted by sponges 14 partially accommodated in containment elements 15 fitted on respective arms 16 which are in turn fixed to the supports 6 proximate to the belts 8 and externally to the line 2.
The sponges 14 absorb, by sliding, part of the water entrained by the belts 8 and remove from the belts the abraded material that has adhered to them.
The arms 16 are provided with longitudinal slots 17 for adjusting the distance, and therefore the contact pressure, between the sponges 14 and the belts 8.
It is also noted that in order to maintain the abrasive effectiveness of the belts 8 at a high level it is necessary to ensure perfect elimination of the abraded material that has adhered to said belts.
For this purpose, the apparatus 1 is provided with cleaning means 18, advantageously immersed in the water of the tray 5, which are constituted by scrapers 19 arranged proximate to the belts 8.
The supports 6 are fitted on respective footings 20 which are fixed to the frame 3 and are provided with means for adjusting their position, and therefore the position of the supports 6, with respect to the line 2 for conveying the tiles P.
In this way, the distance between the abrading means 4 is adapted to the dimensions of the advancing tiles P, so as to ensure contact between the belts 8 and the edges of said tiles.
The adjustment means are not shown, since they are of a conventional type and are manually adjustable by means of a crank 21.
The supports 6 can move about substantially horizontal axes formed by first pivots 22 which are rigidly coupled thereto and are coupled to first locking means 23 connected to the footings 20.
The rotations of the supports 6 about the horizontal axes allow to adjust the inclination of the belts 8 on the vertical plane.
Moreover, the supports 6 can move about vertical axes formed by second pivots 24 which are fixed to the footings 20 and are coupled to second locking means 25.
The translatory motions of the supports 6 along the pivots 24 and the rotations of the supports 6 about the vertical axes respectively allow to adjust the elevation and the inclination on the horizontal plane of the belts 8.
In the illustrated embodiment, the locking means 23 and 25 are formed as a single block for connecting the first and second pivots 22 and 24.
The adjustments allowed by these movements allow to arrange the belts 8 in different positions, so as to always ensure their contact with the edges of the tiles P regardless of their inclination and/or shape.
The tray 5 is provided with means 26 for supplying the water and with means 27 for discharging the water and the abraded material.
The discharge means 27 are constituted by a duct 28 which is connected to the discharge outlet 29 formed in the bottom 30 of the tray 5 and is provided with a cock 31.
There are also overflow-preventing means 32 which are associated with the tray 5 in order to prevent the level of the water contained therein from exceeding a preset value.
The overflow-preventing means 32 are constituted by an overflow duct 33 in which one end lies at the maximum intended level of the water and the opposite end is connected to the discharge duct 28 below the cock 31.
The operation of the invention is as follows: after adjusting, by acting on the crank 21, the distance between the supports 6 according to the width of the tiles P that advance on the line 2 and the inclination of the belts 8 with respect to the edges of the tiles P by means of the first and second pivots 22 and 24, the drums 7 are turned about their axes by the motor drive means 10.
The belts 8 are actuated and abrade the excess material present on the edges of the tiles P; this operation is facilitated by the fact that the belts 8, being partially immersed in the tray 5, carry with them part of the water with which they wet and soften said material.
The abrasive effectiveness of the belts 8 is kept constant by the continuous elimination of the abraded material that has adhered to them by the sponges 14 and of the scrapers 19.
The elasticity of the belts 8 allows to deburr tiles P which belong to a same production run but have different diameters and/or sides which are not perfectly parallel, or tiles and/or profiled elements having undulated or contoured edges, without having to continuously adjust the relative distance of the supports 6, at the same time protecting the integrity of the treated products.
The plates 12 allow to modify the transverse elasticity of the belts 8; by fixing them at gradually smaller distances with respect to the belts 8, one in fact obtains a corresponding gradual reduction of the deformability of said belts, which in the extreme case can assume a substantially rigid behavior.
In this way it is possible to adapt the abrasive action of the belts 8, whose effectiveness remains unchanged, to the type of product being treated: undulated edges, profiled elements, unfired products having different consistencies require greater elasticity of the belts 8, which simply have to follow the edges and remove the excess material without applying damaging pressures to said products; on the contrary, tougher products require greater rigidity of the belts 8, which thus apply to the product a stronger abrasive action caused by higher contact pressure.
Moreover, the provision of the belts 8 with a circular cross-section allows to reduce the waste of material and the maintenance costs; their gradual wear in fact only reduces the diameter of their cross-section but does not reduce their abrasive capacity, which remains unchanged for long periods of time, allowing to drastically reduce the frequency of belt replacements.
Finally, the presence of water allows to facilitate the removal of the excess material, to keep clean the belts 8 and to reduce the wear of the belts.
In the embodiment and application of the apparatus 1 shown in Figures 5 and 6, the lower drums 7a are fitted so as to rotate freely and are longer than the upper drums 7b, with respect to which they protrude with an end 34.
Each support 6 further supports an arm 35 whose inclination is adjustable and on which two pulleys 36 are fitted so that they can rotate freely and are arranged so that their axes are substantially horizontal, parallel and offset with respect to the drums 7a and 7b.
A plurality of belts 37 closed in a loop, of the same kind as the belts 8, are wound around the pulleys 36 and the end 34.
The belts 8 and 37, driven by the motor drive means 10, have respective active abrading portions which are mutually inclined: the active portions of the belts 8 abrade the lateral edges of the tiles P, from which they eliminate the glazing burr, and the active portions of the belts 37 abrade the lower edges of the tiles P, from which they eliminate the molding burr.
Figure 7 is a view of a second alternative embodiment of the abrading means 4 of the apparatus 1 according to the invention.
The support 6 of the abrading means 4 supports a third drum 38 which is laterally adjacent to the upper drum 7b and is associated with the motor drive means 10.
A plurality of belts 8 closed in a loop are wound around the three drums 7a, 7b and 38, and their lower passive portion is diverted by belt tensioner means constituted by two jockey pulleys 39 which are associated with the support 6 so as to form a tunnel 40 for the passage of a tile conveyance line P.
In particular, said abrading means 4 with three drums (7a, 7b and 38) are adapted to be arranged between two laterally adjacent lines for conveying tiles P, with the active abrading portions of the belts 8 substantially in contact with the lateral edges of the tiles P of one of the two lines, while the tiles P of the other line pass through the tunnel 40 formed by them.
In the application of the apparatus 1 shown in Figures 8 and 9, two lines L1 and L2 are arranged side by side and parallel to each other and have the same conveyance direction (indicated by the arrow A), and two apparatuses 1 are fitted along them so as to be mutually spaced and be alternately active on one of the two lines L1 and L2.
The abrading means 4 of each apparatus 1 are constituted by three drums (7a, 7b and 38) which are interposed between the two lines and are active on the inner side of one of them, and by two superimposed drums 7 which are arranged on the outer side of said line.
While one apparatus 1 deburrs the edges that are parallel to the advancement direction A of the tiles P1, the tiles P2 pass without being treated through the corresponding tunnel 40; likewise, the other apparatus 1 deburrs the edges of the tiles P2 that are parallel to the advancement direction A, while the tiles P1 pass, without being treated, through the corresponding tunnel 40.
Advantageously, downstream of the apparatuses 1 there is a unit for turning the tiles P1 and P2 which is adapted to turn them through 90°, and there are two other successive apparatuses 1 which are arranged alternately as described above, so as to deburr the tiles on all four sides.
In practice it has been observed that the above-described invention achieves the intended aim and objects, i.e. to allow to perform deburring in a simple, rapid and versatile manner, to ensure complete removal of the excess materials, to protect the integrity of the treated products, eliminating the formation of defects such as edge chipping and cracks, and to ensure constancy of the abrasive effectiveness and the cleanness of the means used, reducing both maintenance costs and waste of materials.
The invention thus conceived is susceptible of numerous modifications and variations, all of which are within the scope of the inventive concept.
All the details may further be replaced with other technically equivalent ones.
In practice, the materials employed, as well as the shapes and the dimensions, may be any according to requirements without thereby abandoning the scope of the protection of the appended claims.
The disclosures in Italian Patent Application No. MO99A000204 from which this application claims priority are incorporated herein by reference.
Where technical features mentioned in any claim are followed by reference signs, those reference signs have been included for the sole purpose of increasing the intelligibility of the claims and accordingly, such reference signs do not have any limiting effect on the interpretation of each element identified by way of example by such reference signs.

Claims

An apparatus for deburring ceramic products, particularly glazed tiles, advancing on a conveyance line, characterized in that it comprises a frame for supporting means for abrading the edges of said products, said means being arranged laterally to said line, and a tray for containing a fluid which is arranged below said abrading means, said abrading means being flexible, actuatable with respect to said products and partially immersed in said tray.
The apparatus according to claim 1, characterized in that said abrading means comprise at least one support for a pair of superimposed drums which are rotatably supported and on which at least one belt closed in a loop is wound, said drums being associated with motor drive means and being rotationally actuated about their own axes, which are not perpendicular to the direction of advancement of said products.
The apparatus according to one or more of the preceding claims, characterized in that said supports and said pairs of drums are two and are arranged opposite each other on the sides of said conveyance line.
The apparatus according to one or more of the preceding claims, characterized in that said at least one belt is wound and closed in a loop around said at least one pair of superimposed drums and around at least one third drum which is associated with said motor drive means and is arranged substantially laterally to the upper drum of the pair of drums.
The apparatus according to one or more of the preceding claims, characterized in that the lower drum of at least one of said pairs of superimposed drums has an end which protrudes with respect to the upper drum, and in that said abrading means comprise at least one pair of pulleys which are mounted so that they can rotate freely proximate to said protruding end and at least one belt which is closed in a loop and is wound around said pulleys and around said protruding end and whose active portion is inclined and adapted to abrade the lower sides of said edges.
The apparatus according to one or more of the preceding claims, characterized in that said drums comprise cylindrical lateral surfaces which are slotted in order to accommodate the respective belts.
The apparatus according to one or more of the preceding claims, characterized in that said belts are made of a flexible material such as elastomers and rubber.
The apparatus according to one or more of the preceding claims, characterized in that said belts have a substantially circular transverse cross-section.
The apparatus according to one or more of the preceding claims, characterized in that respective abutment plates are fixed on the supports and are arranged proximate to the portions of said belts that are in contact with said products and on the opposite side with respect to them.
The apparatus according to one or more of the preceding claims, characterized in that it comprises adjustable fluid-absorbing means which are associated with said supports and are adaptd to adjust the amount of fluid entrained by said belts and to remove from them the material abraded from said products.
The apparatus according to one or more of the preceding claims, characterized in that said absorption means are constituted by sponges fitted on respective arms which are fixed to said supports proximate to the belts and externally to said line and are adapted to absorb, by sliding, part of the fluid entrained by said belts.
The apparatus according to one or more of the preceding claims, characterized in that said arms are provided with longitudinal slots for adjusting the distance, and therefore the contact pressure, between said sponges and said belts.
The apparatus according to one or more of the preceding claims, characterized in that it comprises means for cleaning said belts which are adapted to remove the abraded material adhered to them.
The apparatus according to one or more of the preceding claims, characterized in that said cleaning means are immersed in the fluid that is contained in said tray and comprise at least one scraper which is arranged proximate to said belts.
The apparatus according to one or more of the preceding claims, characterized in that said supports are fitted on respective footings associated with said frame.
The apparatus according to one or more of the preceding claims, characterized in that said footings comprise means for adjusting their position and the position of the supports, with respect to said product conveyance line.
The apparatus according to one or more of the preceding claims, characterized in that said supports can move about substantially horizontal axes.
The apparatus according to one or more of the preceding claims, characterized in that said supports can move about substantially vertical axes.
The apparatus according to claim 17, characterized in that said horizontal axes are formed by first pivots which are rigidly coupled to said supports and are coupled to first locking means which are connected to said footings, the rotations of said supports about said axes being adapted to adjust the inclination of said belts on the vertical plane.
The apparatus according to claim 18, characterized in that said vertical axes are formed by second pivots which are fixed to said footings and are coupled to second locking means, the translatory motions of said supports along said pivots and the rotations of said supports about said axes being adapted to adjust, respectively, the elevation and the inclination on the horizontal plane of said belts.
The apparatus according to one or more of the preceding claims, characterized in that said tray comprises fluid supply means and means for discharging the fluid and the removed material.
The apparatus according to one or more of the preceding claims, characterized in that said discharge means comprise an outlet which is formed in the bottom of said tray and is connected to respective ducts provided with corresponding cocks.
The apparatus according to one or more of the preceding claims, characterized in that said tray comprises overflow-preventing means which are adapted to prevent the level of the fluid contained in the tray from exceeding a preset value.
The apparatus according to one or more of the preceding claims, characterized in that said overflow-preventing means comprise overflow ducts which are connected to said discharge ducts.