The present invention is related to a method used to give the surfaces of natural stones such as marble, travertine and the like, a weathered and aged appearance. By this method the stones have a surface with soft irregularities an a natural brightness that occur after a long term usage.

The most important common disadvantage of the methods used in the prior art to give an aged appearance to the stones is that they can be produced in a very limited amount. In one of these methods, drums machines that rotate around their own axes with cylindrical drums of various sizes are used. A mixture of sand, gravel, abrasive crumbs, etc. is placed in these drums so that at least a quarter of the interior volumes filled. After adding a certain amount of water, natural stones with the dimensions generally of 10x10 cm and maximum 30x30 cm arc introduced in the drum. Although the amount introduced varies according to the size of the drum it is limited up to 10 to 15 square meters. The drum starts to rotate for 60 to 100 minutes. The stones, surfaces of which have gained an aged appearance by rubbing and striking against each other, are removed from the tank and washed. The loss ratio of this process may be up to 40 to 50%.

Another method is providing the stones with an aged appearance by using acid. In this method, sulfuric acid is poured on the stones and a rough surface is obtained by the dissolution and enlarging of the natural pores of the stone under the effect of acid.

This method is not available for mass production and as the acid used is very dangerous it may lead to damages to the workers during production process and the to the users if the product is not washed thoroughly. Since it is not possible to re-use the used acid for another process, acid consumption is considerably high, and the method is costly.

Yet another method which is known as sanding is based on the principle of blowing specific sand particles on the stones by the aid of air. The hard sand particles striking on the stone surface, enlarge the natural pores in the structure of the stone and make a rough surface. Main problem seen in this method is sand supply and its residue because sand looses its characteristics after being used once or twice and thus becomes a quite expensive method. Besides the roughness provided by this method is not so significant. Furthermore the brightness resulting from natural usage can never be attained. The object of the present invention is to realize a stone-aging method which results in giving the stone surfaces a natural, aged appearance, wherein an economical and efficient production can be made in comparison with the method used in prior art in conformity with the existing natural stone processing technique without changing the machinery and environment used in thiese techniques.

The method applied according to this object of the invention reveals none of the disadvantages seen in the prior methods and the amount of production is at least five times more than the precedent methods. Production is simpler and more fluent.

By this method, clean and ready to be used material can be produced in a short time without any requirement for various machinery and chemical substances as in the other methods. There is not any size limitation for the stones to be aged by this method; stones of various sizes may be aged

efficiently. In addition to this size problem, thickness of the stones also creates an important problem for the other methods. Loss ratio for thin stones is quite high. However in the method of the present invention the thinness of the stone does not effect the production and does not increase losses. Furthermore, when compared with other methods, with this method of the present invention, the most satisfactory result is obtained from the point of obtaining a natural brightness.

DETAILED DESCRIPTION OF THE METHOD OF THE INVENTION

The method of the present invention, related to giving the stones an aged appearance is described in detail referring to the attached drawings, wherein; Figure 1- is the general view of the polishing machine;

Figure 2- is the general view of the head consisting of fringed spiral brushes placed on the flange.

As the method of the present invention can be realized easily by using the machinery employed by the existing systems treating the natural stones in order to obtain a smooth and bright surface and as it is applied after a certain step of the said process, it would be appropriate to explain the existing natural stone treatment technique.

In the known natural stone treatment technique, the stones are cut in three different dimensions, namely as plates, tiles and slabs, by the machines known as "este" and mill saw, after being taken out of the quarries as big blocks.

After removing the uneven sections at the ends of the stones, in the head- cures, the stones are guided to the polishers.

The object of using the polisher is to provide the stones with smooth and as bright as possible surface. In this machine, the stones are passed on a conveyor belt below the heads with diamond tips, known as calibrators.

These heads which calibrate the stone thickness by the help of diamond tips, may be two or more in number. The calibrators are stationary elements except that they may be moved upwards and downwards in order to bring the stone thickness to the desired degree. A lot of water is used in this step. The material exiting from the calibrators are left after the coarse residue is taken off. After this process, the stones are brought below the abrasive heads which rotate around their axes and can be moved up and down by hydraulic or pneumatic means.

Given series of these heads are formed by assigning them numbers such as 100, 200, 300, 400 and each head contains seven or more abrasives which are types of grindstone.

The last series used are named as "extra". The sequential order of these series varies according to the number of the heads in each machine and the type of the stone. Abrasives of the 100 and 200 series perform only wearing-out (grinding) treatment on the stone surface whereas those of the subsequent 300 and 400 series prepare the stone for polishing without grinding it. The "extra" series formed by polishing stones realizes the polishing treatment. Amount of water and the pressure of the heads decrease as the number of the series increase and they arc reduced to minimum for the "extra" series.

After being processed by these abrasive head series, the material is ready to be used; If desired, it may be placed in the material dimensioning machine to be brought to the desired dimensions and then undergoes the chamfering (beveling) process. This beveling process is generally used for the stones with tile dimensions, and its primary object is to angulated the stones. The stones angulated by the lateral calibrators are then brought below the abrasive heads which are inclined 45 degrees by the conveyor band. These heads, by moving up and down, provide the stones with a 45 degrees and 1 mm wide standard beveling as the result of pneumatic pressure. Here, the shaφness on the four top edges of the stone is removed. The abrasive heads are different from the polishing heads; they operate at a 45°angle to the stone surface and contrarily to the polishing heads which can treat the whole surface of the stone, they can effect only one edge of the stone, on an area of maximum 2 to 3 mm. width. During the process, water is used as much as possible. After completing these steps, stones having a bright appearance arc dried by hot or cold air fans and packed after being classified.

The ageing process within the scope of the method of the present invention is realized after the stones exit from the 100 and 200 series of the abrasive heads, their surface wearing-off processes being completed, at the stage of starting the use of the polisher, of the above esplained stone processing technique. As of this stage, the stone surfaces are given an aged appearance by using cup-shaped brushes with helical and fringed wire bristles.

In the polisher shown in Figure 1 , stones conveyed by the conveyor belt (D) are brought below the surface wearing abrasive heads (B) known as 100 and 200 series after being reduced to the desired thickness at the calibrators (C ) Material coming from 200 series, in the dimensions of tile, slab or plate, has a smooth surface.

The part after the 200 series of the polisher has been modified and the flanges supporting the abrasives are replaced by flanges (E) supporting cup-shaped wire-brushes that can be fastened by bolts or any other way to provide a safe placement, in the abrasive heads.

Cup-shaped wire brushes are preferred, as they are available in the market and provide best results. Cup-shaped wire brushes are placed peripherally at equal distances on the lower surface of each flange, arranged in a circular structure. The number of these brushes is generally nine, though it may vary according to the hardness and pore structure of the stone. A single wire brush of a larger diameter may be used instead of a number of brushes on a flange. The cup shaped brushes (F) are stationary, but their flanges are pivotable. For extamely hard stones, the brushes may also be made so as to rotate around their axes. This system which facilitates abrasion is also the operational technique of the abrasive heads used in granite processing method. For marbles and travertine, use of stationary wire brushes are sufficient. In the method of the present invention, two types of cup shaped wire brushes; namely helical and fringed brushes are used. The helical type has harder and thicker [6~istles. For this reason the stones coming from 200 serbrasive heads are first introduced in the drum below the heads with these brushes, in the polisher. In this stage an excessive amount of water is utilized. Water decreases wire consumption as well as wearing- off.

The number of the heads supporting helical type of brushes arc determined according to the hardness of the stone. For stones of normal hardness, this number is seven or nine The number of abrasive heads may be reduced and that of wire brushes may be increased or vice versa according to structural properties of the stone.

A natural brightness as if it results from a long term usage is provided for the stone surfaces by using more flexible and softer cup-shaped wire brushes. At this stage the amount of water used may be adjusted according to desired brightness, however water consumption is relatively reduced. After being subjected to these processes, the stones gain a naturally aged appearance. If the desired size is that of a plate, the stone is washed and thus the process is completed. If the size of the stones is that of slab, then sizing is made and in case of tile typed stones, after sizing, bevelling is performed.

In the bevelling machine, four top edges of the angulated stones are bevelled by means of double helical type wire brushes attached on the abrasive bearings of bevelling heads. Bevelling made by these wire brushes result in rounder lines than those made by abrasives. The bevelled edges have a duller appearance than the front face of the stone. After this process the stones are washed and dried to be packed. If the edges are desired to be bright, stones are subjected to sizing process after being cut and only angulated in the bevelling machine without being bevelled. Subsequently the stones aged by the method of the present invention are subjected to washing and drying processes and become ready to be used. By this way, all of the exposed top surface of the stone has a uniformly aged and bright appearance.