FR2787739A1 - Paving stone manufacturing procedure from block of natural rough stone involves sawing of block into slices, sawing of slice into billets and splitting of billet into paving stones - Google Patents

Abstract

Procedure involves sawing block along parallel cutting planes into slices of specified thickness. Slice is sawn along parallel cutting planes perpendicular to large faces into billets (3). Billet is split into individual paving stones by applying cleaving cutters (C1,C2,C3,C4) against each of four previously sawn faces. Size of paving stones is reduced, if necessary, by second cleaving operation.

Description

The present invention relates to a method for manufacturing pavers. She

  also relates to the pavers obtained by the implementation of this process.

  Various types of pavers are known which are made from rough blocks of natural stone, such as granite, quartzite, limestone, marble, etc.

  In the remainder of this description and in the claims, it is

  will mean by the terms "splitting", "sawing", "splitting" and "cleavage" the following techniques: - splitting: technique which consists in making holes in a rough block, in placing corners and driving them into the block using a mass. The block then cracks according to a random separation plane, linked to the arrangement and orientation of the minerals. This plan is generally bumpy and irregular. There is no precision as to the regularity of the dimensions of the pavers obtained; - sawing: cutting using a rotating disc, the peripheral teeth of which are filled with diamond pellets, or other material giving the same effects, such as a diamond cable, a multi-blade chassis, etc. The sawn faces are perfectly flat and smooth; - cleavage or splitting: technique which consists in applying knives subjected to a strong hydraulic pressure against two opposite faces, in a direction perpendicular to these faces. The flatness and orientation of the cleaved surface depends greatly on the regularity of the surfaces on which the cleavage knives are supported. If these surfaces are dented, the knives take an unstable support, so

  that the cleaved surface is particularly irregular.

  The most widely used pavers, called "mosaic" pavers have six identical and rough faces, that is to say embossed, obtained for example by splitting or splitting a block of stone. These pavers are particularly uncomfortable when

  walking and noisy when passing vehicles.

  The techniques used for the manufacture of these "mosaic" pavers lead to deformed faces. Consequently, the pavers obtained have dimensions which vary enormously. This is particularly problematic for the realization of pavements, insofar as the dimensions of joints between pavers are very

  irregular. The time devoted to their installation is therefore necessarily long.

  Another type of paver has a flat, smooth or grainy upper face if a non-slip surface treatment is carried out. The faces of the perimeter

  are delimited by cleavage, while the underside is obtained by cleavage or sawing.

  The manufacture of these pavers is limited to the production of pavers with a square or rectangular base.

  laire, small formats. Indeed, during the cleavage operation, the knives take

  support on totally irregular faces. On this irregularity will depend the orient-

  ation and the flatness of the cleavage plane. It is understood that as soon as the dimensions of the block to be obtained are large, the cleavage plane will most likely be

  particularly poorly oriented and bumpy.

  These techniques do not make it possible to manufacture pavers with low dimensional tolerances, or large pavers. These constraints prevent architects and project owners from planning layout projects using such paving stones

  and install these with narrower joints than usual.

  Another type of paver has six sawn faces. Of course, such a block is of remarkable dimensional precision, but of a very high cost price,

  especially because of the rapid wear of the diamond points with which the saw is fitted.

  The present invention aims to solve these problems.

  In other words, it aims to provide a process for manufacturing pavers, which is more economical than that of sawing the six faces, while maintaining very low manufacturing tolerances, so as to obtain a perfect

dimensional regularity.

  This process for manufacturing paving stones, from a raw block of natural stone, is characterized by the fact that it consists of: a) sawing said block according to parallel cutting planes into a series of slices with two large opposite sawn faces , of predefined thickness; b) sawing each slice along cutting planes parallel to each other and generally perpendicular to its large faces, in a series of billets; c) cutting each billet into individual blocks by cleavage, by applying cleavage knives against each of the four previously sawn faces; d) if necessary, reduce the size of the pavers obtained by one second

  cleavage operation, the cleavage plane being directed perpendicular to that of step d).

  By implementing this process, four of the six faces of the paver obtained at

  step c) are carried out by sawing.

  The cleavage step of the fifth and sixth faces is carried out while the knives bear on particularly flat faces because they are sawn, so that the cleavage plane obtained is particularly regular. This also makes it possible to use monobloc knives rather than knives with contiguous teeth, so that the cutting force is perfectly distributed. In this way, pavers of particularly exceptional dimensional regularity are obtained, at a cost price much lower than that of a paver with six sawn faces. Furthermore, according to other advantageous but non-limiting characteristics of this process:

  - the plane in which the cleavage knives are contained is perpendicular to

  four sawn faces; - The plane in which the knives are supported on two parallel sawed faces is different from that in which the knives are supported on the other two parallel faces; - after step a), we proceed to a surface treatment of two large sawn faces, aimed at making them grainy - after step d), we proceed to a surface treatment of the sawed face of the pavers as well obtained which is opposite to the previously cleaved face, aiming to make it grainy while breaking its edges; - Said surface treatment consists of flaming, bush hammering, shot blasting, water jet treatment, or a combination of these; - in step b), the cutting planes are substantially parallel to the large

sides of the slice.

  The invention also relates to pavers obtained in accordance with

  method according to one of the characteristics mentioned above.

  Other characteristics and advantages of the present invention will appear

  on reading the detailed description which follows of a preferred embodiment and

  not limiting. This description will be made with reference to the accompanying drawings in which:

  - Figure 1 is a perspective view of a raw block of natural stone, from which the manufacturing process according to the invention is implemented; - Figure 2 is a perspective view of a wafer obtained at the end of step a) of the process; - Figure 3 is a partial perspective view of a billet obtained at the end of step b) of the process; - Figures 4 and 5 are perspective views of pavers obtained respectively after one of steps c) and d); - Figure 6 is a perspective view of a paver obtained according to the method according to one invention, including a surface treatment step; - Figure 7 is a front view of a machine for setting

  performs the cleavage operation of step c).

  The method of manufacturing pavers according to the invention is implemented

  work from a raw block 1 of natural stone such as that shown in Figure 1.

  It is for example a block of granite, quartzite, limestone,

  marble or any other type of stone.

  It is a block from a quarry, which has a shape

  substantially parallelepipedic. We have referenced 10 and 11 its upper and lower faces

  better. Its opposite longitudinal faces are referenced 12 and 13, while its faces

  opposite crosses are referenced 14 and 15.

  Of course, being a raw block, the faces described above are

  very irregular in appearance and are not strictly parallel two by two.

  The first step of the method according to the invention consists in sawing this block according to parallel cutting planes, in a series of slices with two large faces.

  sawn opposites of predefined thickness.

  In Figure 1, there is shown by broken lines the aforementioned parallel sectional planes Pl which, in the present case, extend substantially parallel to the

two longitudinal faces 12 and 13.

  Such an operation is carried out in a completely conventional manner, using a circular saw, the peripheral teeth of which are trimmed with diamond points. This technique, widely tested in the past, leads to a regularity of

  almost perfect cut and allows to obtain perfectly flat and smooth sawn faces.

  This operation can of course be carried out by other technical means giving

the same effects.

  As an indication, the thickness of the slices is of the order of sixteen centimeters. Of course, depending on the size of the block 1, a greater or lesser number of slices is obtained, a copy of which 2 is shown flat and in perspective at

Figure 2.

  This section has two large opposite sawn and parallel faces 20 and 21. Its longitudinal rough faces are referenced 22 and 23 while its faces

  transverse, also raw, are referenced 24 and 25.

  It should be noted that following the sawing step of block 1, the end edges are eliminated, that is to say those whose large face is rough. These slices are by

  example crushed or scrapped.

  The second step of the method according to the invention consists in sawing each edge 2, according to cutting planes parallel to each other and generally perpendicular

  with large faces 20 and 21 previously sawn.

  In Figure 2, there is shown in the form of broken lines

  pus, these parallel sectional planes P2. As an indication, the cutting plans are distant

two to two of ten centimeters.

  This sawing operation is carried out with the same type of material

than the one described above.

  Preferably, the cutting planes extend parallel to the largest

  size of slices 2, so as to limit the number of cuts.

  In this way, we obtain a series of elongated billets 3 and we eliminate those

  which have a rough longitudinal face.

  The other billets then present the physiognomy of that which is

shown in Figure 3.

  This billet has the shape of a long parallelogram with a rectangular base.

  In a different embodiment, this parallelogram could have a square base.

  In any event, the physiognomy of the billet depends on the shape you want

get for the cobblestones.

  Referring again to FIG. 3, the billet 3 has two raw end faces 24 and 25. Its upper and lower faces 20 and 21 as well as its longitudinal faces 30 and 31, delimited by the two sawing operations, are perfectly

flat and smooth.

  It is this regularity of surface which will make it possible to implement

  the cleavage operation of step c).

  Indeed, this step consists in cutting each billet 3 into individual blocks, by a cleavage operation, using knives supported on each

  four sawn faces 20 and 21, 30 and 31.

  Advantageously, the cleavage plane is perpendicular to the four sawn faces. This is what has been represented in FIG. 3, where the cleavage planes P3 have been

  shown as broken lines.

  FIG. 7 represents a machine used to implement this

cleavage operation.

  It is a machine 6 which comprises a frame 60 with a base 61 for receiving a cleavage billet. The flat upper face of this base is provided with a knife C2 formed by a monobloc blade D2, the free cutting edge of which extends

in a horizontal plane.

  Parallel to a series of vertical columns 62 extends a jack V1 whose end of the rod, guided along the columns 62, is furnished with a knife C l,

also with monobloc blade D1.

  The cutting edge of the blade Dl extends strictly in the same plane

vertical than that of blade D2.

  Furthermore, the machine is equipped with two other cylinders V3 and V4 with a horizontal axis, arranged opposite one another. Each is provided, at the free end of its rod, with a knife C3, respectively C4. The cutting edge of these knives, directed

  vertically, also extends in the same plane as that of the knives C1 and C2.

  In a variant, the knives, and particularly the knives C 1 and C2,

  could be formed by a juxtaposition of individual teeth.

  As shown in this figure 7, a billet 3 is laid flat, parallel-

  ment to the base 61 of the machine so that one of its faces rests on the blade D2 of the knife C2. Of course, the billet support means make it possible to keep it in stable equilibrium against the blade D2. In the case shown here where the billet has a section in the form of an elongated rectangle, one of its large faces is applied against the blade D2. We can then control the cylinders V1 to V3 so that their knives

  respective bear against the corresponding faces of the billet.

  As an indication, such a machine is capable of applying at the level of

  knife teeth, a pressure of around 2.4 tonnes / cm2.

  Insofar as the four sawn faces of the billet on which the knives rest have perfect flatness, the pressure exerted by the jacks results in a

  perfectly flat and uniform cleavage plane.

  Still with reference to FIG. 7, two mixed lines have been represented

  other 3 'and 3 "billet profiles of smaller dimensions.

  At the end of this cleavage operation, a block 4 is obtained whose face 40 has been delimited by cleavage. As it is a billet end block, the face 24 opposite the cleaved face 40 is rough. If it was a paving stone coming from a part

  through the billet, we would have been dealing with two identical cleaved faces.

  Assuming that the block 4 thus obtained has dimensions too large for later use, a second cleavage is then carried out in a plane P4 perpendicular to the aforementioned plane P3. In this way, we get two new

  block 5 and 5 ', the cleaved faces of which bear the references 50 and 50' respectively.

  In the end, except for the pavers obtained at one end of the billet, we have

  dealing with pavers which have at least three sawn faces, the others being cleaved.

  The fact that at least three of the faces are obtained by sawing means that the edges which delimit them two by two are particularly regular. This opens up the possibility of using the pavers for paving by significantly reducing the width of the joints between pavers. The edges are regular, layout plans can be put

in action.

  In addition the fact of having paving stones with, opposite each other a

  cleaved side and sawn side, allows to consider two laying directions for paving.

  When the sawn side is intended to be turned upwards, the face

  cleaved, by the irregularity of its surface, provides better anchoring on the ground.

  Note also that there may be provided on all or part of the sawn faces of the pavers a surface treatment intended to make them rough, grainy and

non slip.

  It may, for example, be a bush hammering, flame treatment,

  shot blasting or water blasting, or a combination thereof.

  If this surface treatment is carried out on the opposite faces of the sections 2, it can be arranged so that the treatment does not affect the edges. If the surface treatment is carried out on the pavers (Figure 6), the small surface area of the sawn faces will cause the treatment to affect the edges, making them irregular. This gives an aged appearance

  to the pavers obtained, visual effect which may be desired for certain applications.

  The pavers obtained in accordance with the invention ensure guaranteed walking comfort. Due to the techniques used, they can be used in formats larger than existing pavers and, therefore, can be applied to sectors of activity such as construction, for example as cladding

vertical of buildings.

  New shapes can be created, in particular pavers with a square, rectangular, trapezoidal or parallelogram top face. To do this, it suffices in step c) to orient a pair of knives C1 and C2 or C3 and C4, in a

  direction different from that of the other pair of knives.

  The implementation of the process makes it possible to obtain low manufacturing tolerances and a perfectly calibrated paving stone, so that their installation makes it possible to make relatively significant time savings.

Claims (8)

  1. Method for manufacturing pavers (4, 5, 5 '), from a raw block (1) of natural stone, characterized in that it consists of: a) sawing said block (1) according to plans parallel cutting (P1) into a series of slices (2) with two large opposite sawn faces (20,21), of predefined thickness; b) sawing each section (2) along cutting planes (P2) parallel to each other and generally perpendicular to its large faces (20,21), in a series of billets (3); c) cutting each billet (3) into individual blocks (4) by cleavage, by applying cleavage knives (C a, C2, C3, C4) against each of the four faces (20, 21, 30, 31) previously sawn; d) if necessary, reduce the size of the blocks (4) obtained by a second cleavage operation, the cleavage plane (P4) being directed perpendicular to that of step d). 2. Method according to claim 1, characterized in that in step c), the plane (P3) in which are contained the cleavage knives (C1, C2, C3, C4) is   perpendicular to the four sawn faces (20, 21, 30, 31).   3. Method according to claim 1, characterized in that, the plane (P3) in which the knives are contained (C1, C2) bearing on two parallel sawed faces (20, 21) is different from that in which are contained knives (C3, C4)   bearing on the two other parallel faces (30, 31).   4. Method according to one of claims 1 to 3, characterized in that,   after step a), a surface treatment of two large faces is carried out   sawn (20, 21), to make them grainy.   5. Method according to one of claims 1 to 3, characterized in that   after step d), a surface treatment of the sawn face (20,   21) pavers thus obtained (5, 5 ') which is opposite to the face (50, 50') previously cleaved   aimed at making it grainy while breaking its edges.   6. Method according to claim 4 or 5, characterized in that said surface treatment consists of flaming, bush hammering, shot blasting,   water jet treatment, or a combination thereof.   7. Method according to one of claims 1 to 6, characterized in that   step b), the cutting planes (P2) are substantially parallel to the long sides of the edge (2).   8. Pavers obtained according to the method according to one of claims 1 to 7.