PROCEDURE AND DEVICE FOR THE COATING OF PARTS FROM NATURAL OR KUNSTLICHEN MATERIALS

The present invention relates to the technical field of covering and it refers to a method and machine for covering element made of natural or synthetic materials, for instance stone, ceramic, wood and by-products thereof and conglomerates.

It is known the use of a layer of resin or of resin based paint, on materials, for instance covering materials, in order to make water and wear proof said materials or unaffected by staining.

Said use can be carried out by means of a belt fit for conferring a predetermined surface finishing, for instance smooth, embossed, rough on the covering surface. A drawback of known method and machines for manufacturing said coverings, consists in that they cannot be used on elements having irregular surfaces and three-dimensional profile, such as, for instance, bevelled or carved furniture elements and architectural elements. Document WO 02/068189 A discloses a machine and method for coating elements in which the element is sandwiched between a band and a belt, and where the coating is cured through the band with radiations.

An object of the present invention is to propose a method and machine for covering elements made of natural or synthetic materials, which can be used, also on three-dimensional or irregular shaped faces of said element.

Other object is to propose a method and machine, which allow obtaining a predefined superficial surface finishing in a simple, economic and fast way without requiring the processing of element material.

The above-mentioned objects are achieved accordance with the claim content.

The characteristics of the invention are underlined in the following with particular reference to the attached drawings, in which:

• figure 1 shows a front, schematic, partial section view of the machine of the present invention in which some parts have been removed for better underlining others;
• figures 2 to 5 partially show respective variants of the machine of figure 1.

With reference to figure 1, numeral 1 indicates the machine for covering elements made of natural or synthetic materials, including delivering means 2 fit for sprinkling a polymerisable fluid material 3, consisting of a resin or a resinous paint, on a portion of each element 4 to be covered.

The machine 1 is provided with circular translation belt means 13 rotated by respective rolls and made gas permeable by means of many through holes 14. The upper portion of said belt means is fit to translate the elements 4 which mate circular band means 5, of flexible and elastic type, moved by respective rolls 12 simultaneously with the element 4. The band means 5 are maintained facing and almost mating a portion of belt means 13 by means of two of rolls 12, which are elastically mobile and moved away from said portion of belt means 13 in order to allow the passage of elements 4 also having notable and irregular thickness.

The lower face of the portion of belt means 13 which support the elements 4, mates an opening 9 of a negative pressure container 8 of the pressure means 7 in which it is maintained a negative pressure by means of vacuum pumps of known type and not shown.

The negative pressure container 8 has a longitudinal dimension, with respect to the motion of band means 5 and belt means 13, longer than the dimension of the portion of the band means 5 leaned out to those to carpet 13 and it extends also upstream such portion.

The negative pressure subjects the belt means 5 to a pressure difference and therefore to a force in direction of the element to be covered 4 supported by the belt means 13.

Consequently the band means 5 are compressed by the atmospheric pressure against the element 4 to whose upper surface they adhere exerting a pressure, toward said element 4, on the covering polymerisable fluid material 3.

The machine is provided with first activation means 6 of the polymerisation positioned toward the portion of band means 5 fit for mating the elements 4. Said first activation means 6 provide the material 3 with excitation energy for the element polymerisation, at least partial.

The first activation means 6 of polymerisation include a group of electromagnetic radiation sources capable to emit at least in infrared or visible or ultraviolet or radio frequency band or microwaves or X-rays. The emission band of sources is determined in accordance with the type of covering material 3, which is spread on the element 4.

In order to allow the radiations to reach the material 3 causing the at least partial polymerisation thereof, the material of band means 5 is at least partially transparent to said radiations emitted by the sources.

The sources of first activation means 6 are provided with selective filters 18 for instance of quartz type in order to filter the infrared radiation, protecting the band means 5 from heat excesses.

In alternative, the invention provides that the first activation means 6 of polymerisation include a group of accelerated electron sources or a group of heaters. These last ones favour the polymerisation of anaerobic resins that require a moderate heating for their polymerisation, when they are compressed between the element 4 and the band means 5 and therefore they are in absence of oxygen.

The face of the band means 5 fit for mating the polymerisable fluid material 3 is smooth, rough, embossed or with other superficial workings which have to be impressed on the covering 40 obtained by polymerisation of said material 3.

The delivering means 2 include a set of nozzles for the fluid material 3, oriented toward the surface to be covered of the elements 4 and they are positioned upstream the band means 5 with respect to the path of said elements.

The machine also includes second activation means 19 of polymerisation positioned downstream the band means 5 and the first activation means 6. The second activation means 19 have the purpose to complete the polymerisation and they can heat the material 3, not having infrared filters.

Through said heating, the second activation means 19 also complete the consolidation of the material 3 that, being penetrated into the porosities and cavities of element 4, has not been reached by the radiations of first activation means 6.

The invention further provides that the second activation means 19 can be positioned upstream the band means 5.

The machine also includes support and translation means 20, of roll or belt conveyor type, positioned upstream and downstream the band means 5 and fit for supporting and translating the elements 4.

The invention preferably provides that the band means 5 and translation belt means 13 are respectively made of silicone material and of vetroteflon and that said band means 5 and belt means 13 have a transversal width larger than the width of elements 4 to be covered.

In the variant of figure 2 the nozzles of delivering means 2 are oriented toward the face of the band means 5 fit to mate the elements 4. The delivering means 2 include cleaning means 15 mating the band means 5 upstream the nozzles and having a motorized brush 16 and an aspirator 17. In this variant the fluid material 3 is sprinkled on the elements 4 by the cooperation of the delivering means 2 and of the band means 5 and these last ones are cleared from the material residues by the cleaning means 15.

The variant of figure 3 is particularly fit for an element 4 shaped as flexible and continuous strip wound on a reel. The machine of this variant includes feeding means 22 and collecting means 23 positioned respectively upstream and downstream the band means 5 and respectively provided for unwinding the material 4 on a reel and for winding of the covered material 4. The machine also includes corona treatment means 24 positioned upstream the portion of band means 5 fit for mating the element 4 on a reel. Said corona treatment means 24 or equivalent treatment means with plasma or aggressive solvents predispose the surface of element 4 to the fixing of material 3 and covering 40, carried out from the polymerisation of said material 3.

In the variant of figure 4, fit for the alternate operation, the band means 5 consist of a membrane of a membrane press 30.

The pressure means 7 also include a pressure container 10 having an opening 11 to whose edge the band means 5 are fixed. The pressure container 10 is moved away from and close to the belt means 13 by the press mobile portion and contains the first activation means 6.

The negative pressure container 8 has at the respective opening 9 a perforated surface 31 fit for supporting the translation belt means 13.

In the variant of figure 5, the band means 5 have ends wound on respective unwinding and winding rolls 12. In said variant the band means 5 can be moved away very much from the translation belt means 13 for the passage of elements 4 having also huge and very irregular dimensions.

The operation of the machine 1 in accordance with the method for covering elements made of natural or synthetic materials provides:

• to sprinkle a portion of at least an element 4 with a polymerisable fluid material 3 through the delivering means 2;
• to position the portion sprinkled of material 3 of the element 4 against the band means 5 and to subject these last ones to a pressure difference by the pressure means 7 in order to transmit to the band means 5 a force in direction of element 4 to be covered;
• to submit the fluid polymerisable material 3 sprinkled on the element 4 to the effect of first activation means 6 of polymerisation;
• to move away from the band means 5 the element at least partially covered of the material 3 at least partially polymerised.

The method provides to direct the delivering means 2 straight toward the element 4 or, in alternative, toward the portion of band means 5 fit for mating the element 4.

The band means 5 are subject to the pressure difference through a negative pressure of a negative pressure container 8 and eventually through a pressure of a pressure container 10.

The finished bright, opaque or embossed surface of band means 5 confers a corresponding bright, opaque or embossed superficial finishing to the covering 40.

The method further provide to subject the material 3 sprinkled on the element 4 to a infrared, visible, ultraviolet, radio, microwaves, X rays radiations or to electron bombardment or heating through respective sources or heaters of first activation means 6 in order to achieve the hardening at least partial of said material; said method also includes the phase, following the action of first activation means 6, to subject the material 3 sprinkled on the element 4 to the effect of second activation means 19 in order to complete the hardening.

It is important to observe that the machine and the method of the invention allow manufacturing a covering closely coupled to elements having different natures, shapes and functions.

For instance, the elements may consist of flooring and covering tiles, architectural elements, furnishing and decorative elements, doors, shutters and other furniture elements, made of natural and artificial stone, wood and by-products and substitutes thereof, also conglomerated including dehydrated mud, shells or tests, wastes, glasses, mirrors, organic and inorganic material generally.

The main advantage of the present invention is to provide a method and machine for covering also three-dimensional or irregular shaped faces of elements made of natural or synthetic materials generally.

Other advantage is to provide a method and machine for obtaining predefined superficial surface finishing in a simple, economic and fast way, without requiring the processing of element material.