WO2003041930A1

WO2003041930A1 - Method for making bevel-edged boards, based on hydraulic binders, line and device for producing same

Info

Publication number: WO2003041930A1
Application number: PCT/FR2002/003919
Authority: WO
Inventors: Giovanni Barcaro
Original assignee: Lafarges Platres
Priority date: 2001-11-16
Filing date: 2002-11-15
Publication date: 2003-05-22
Also published as: EP1448347A1; EP1321261A1

Abstract

The invention concerns a method for making boards based on hydraulic binders such as plaster, said boards having bevelled edges. Said method is characterized in that it comprises the following steps: a) a step which consists in inserting, beneath the preform (5), a lath (6, 23) whereof the length is at least approximately equal to the width of the preform (5); a step which consists in removing said lath (6, 23); and b) in cutting the preform at the bevel (8) produced by the lath (6, 23). The invention also concerns a production line for making such boards and a device used for making such boards.

Description

PROCESS FOR MANUFACTURING PLATES WITH TINNED EDGES,

BASED ON HYDRAULIC BINDERS, LINE AND DEVICE

FOR THE PRODUCTION OF SUCH PLATES

The present invention relates to a method of manufacturing plates based on hydraulic binder such as plaster, these plates having thinned edges.

The invention also relates to a production line for such plates and to a device that can be used to manufacture these plates.

It has been known for a long time to make thin longitudinal edges on plasterboard. In fact, American patent No. 1,754,429 and British Patent No. 429,379 already proposed, respectively in 1922 and in 1934, techniques for continuously manufacturing plasterboards having thinned longitudinal edges.

The existence of thinned edges makes possible a satisfactory assembly of two adjacent plasterboards. It allows the space left by the thinned edges to be filled by means of a joining coating, which can then be leveled with the surface of the plates, without creating any additional thickness. In addition, it reduces the risk of cracking between the plates.

The assembly thus produced of several plates constitutes a continuous surface having good flatness ^' . In 1937, US Pat. Nos. 2,238,017 and 2,246,987 attempted to solve the problem of making thinned transverse edges.

The solution proposed by the first of these patents consists in making a transverse groove in the lower sheet of paper by folding the latter before pouring the plaster composition and arriving on the conveyor belt. The transverse groove protruding from the bottom sheet of paper creates, after the sheet of paper on the conveyor belt, a hollow whose walls are oblique. By then cutting the plate at the end of each part at an angle, two plates with thinned transverse edges are obtained. Such a solution is difficult to implement because it requires the installation of special rollers for the production of the groove. In addition, the plate must be cut in two places, which has the further disadvantage of producing a large amount of waste.

The solution proposed by the aforementioned second US patent (US 2,246,987) consists in fixing transversely to the conveyor belt of the line for the continuous production of plasterboard, side bars. This solution has the drawback of requiring the production line to be stopped each time it is desired to modify the length of the plasterboard to be produced. These stops are long because it is necessary to separate the bars from the conveyor belt to move them, then fix them again. Then it is necessary to restart the entire plasterboard production line.

Such a solution is therefore difficult to implement and involves high costs.

Despite the many years that have elapsed since the publication of these patents, no technique has come to provide a satisfactory solution to the problem of producing plasterboards having thinned transverse edges on a continuous line.

This is surprising when you know the advantages brought by such plasterboards and when you know that the use of plasterboard is constantly spreading all over the world.

The invention therefore aims to provide a method for manufacturing plasterboard having thinned transverse edges. This process manages to remedy the drawbacks of the techniques proposed in the prior art.

More specifically, the invention relates to a method of manufacturing a plate based on hydraulic binder, with thinned edges, in which: 1) a hydraulic binder composition is poured over a facing material supported by a conveyor belt, so as to obtain a preform,

2) the hydraulic setting of the hydraulic binder composition is allowed to take place, and

3) the preform is cut, this process being characterized in that a) it further comprises the following steps:

- Before step 2), a slat whose length is at least approximately equal to the width of the preform is introduced under the preform;

- After step 2), said slat is removed; and in that b) the cutting of step 3) is carried out at the level of the thinning created by the slat.

The invention also relates to a production line for plates based on hydraulic binder having thinned edges from a preform comprising a facing material covered with a hydraulic binder composition, this production line comprising a conveyor belt as well as, near this conveyor belt, means for introducing, between the preform and the conveyor belt, a slat whose length is at least approximately equal to the width of the preform.

Finally, the invention also provides a device for the introduction of slats on a conveyor belt with a view, in particular, to manufacturing plates based on hydraulic binder having thinned edges, this device comprising:

- a slatted shop;

- at least one slat,

- Means for extracting one slat at a time from the slat store; - Means for receiving the extracted batten;

- Means for moving the extracted slat in a direction parallel to its length; - Means for supporting the displaced batten in an inclined position; and

- Means for moving the slat moved in a direction parallel to its width. Other characteristics and advantages of the invention will now be described in detail in the description which follows and which is given with reference to the figures, in which

- Figure 1 schematically shows step a) of the method according to the invention; - Figure 2 schematically shows step b) of the method according to the invention;

- Figure 3 shows a plate as obtained by the method according to the invention;

- Figure 4 shows a plate obtained by the method according to the preferred embodiment of the invention;

- Figure 5 illustrates an optional intermediate step of the method according to the invention;

- Figure 6 shows schematically. and in perspective, part of the production line according to the invention;

- Figure 7 shows schematically and in top view, the device according to the invention;

- Figure 8 shows schematically and in side view, the device according to the invention; - Figure 9 shows schematically and in side view a variant of the device according to the invention; and

- Figure 10 shows schematically and in section, a detail of the device according to the invention illustrating one introduction of the slat under the plate based on hydraulic binder, during training.

DETAILED DESCRIPTION OF THE INVENTION

PROCESS ACCORDING TO THE INVENTION

By "transverse edges" is meant in the present description the edges perpendicular to the direction of movement of the conveyor belt in a production line for sheets based on hydraulic binder. Referring to Figure 1, we see a production line of plates produced by casting on a facing material 1 of a hydraulic binder composition 2 and covering with a second facing material 3. The passage of one set under the forming plate 4 gives a preform 5.

The hydraulic binder composition preferably includes plaster.

The facing materials 1 and 3 may consist of sheets of paper or cardboard, glass mats or any material known to those skilled in the art as being able to serve as facing material.

After the preform 5 exits from under the forming plate 4 or from under the equivalent device used in the production line (for example, a roller called in English "master roll"), a batten 6 is introduced between the preform 5 and the start of the conveyor belt 7. The distance between the forming plate 4 and the start of the conveyor belt 7 is such that the preform 5 has not yet had time to harden substantially and is still present great plasticity. The introduction is carried out in such a way that the longitudinal axis of the slat 6 is substantially perpendicular to the direction of movement of the conveyor belt 7.

The slat 6 is then driven by the conveyor belt 7, just like the preform 5. The hydraulic setting and hardening of the plaster composition 2 is then carried out throughout the movement of the preform 5, designated by the arrows A.

According to a preferred embodiment of the invention, the slat 6 is removed before the preform 5 is cut.

Thus, after a certain time, to which corresponds a distance traveled by the preform 5 on the conveyor belt 7, which a person skilled in the art knows how to determine as a function of the speed of movement of the conveyor belt 7 and the setting time of the composition of plaster 2, the hardness of the preform 5 is sufficient so that the slat 6 can be removed without deforming the preform 5 and without the plaster composition 2 come fill the space or thinning 8 (Figure 2) left by the removal of the slat 6.

The removal of the slat 6 can be carried out in any suitable manner. For example, when the length of the slat 6 is greater than the width of the preform 5, the slat 6 protrudes relative to the preform 5, and it can then be removed quickly in a direction substantially perpendicular to the direction of movement of the conveyor belt 7 and away from it. This withdrawal action is illustrated by the arrow B.

The withdrawal of the batten 6 can also occur by the fall of this batten 6 in the space situated between two rollers constituting the system of conveyor belts which, in general, is not continuous throughout the production line, but is formed by several mats driven by rollers between which there are free spaces.

After the removal of the slat 6, the preform 5 continues to move, still driven by the conveyor belt 7 and the hardening of the plaster composition 2 continues. As can be seen in FIG. 2, when the thinning 8 arrives at the height of the cutting device generally constituted by a roller provided with a knife 9, the latter starts up and cuts the preform 5. We obtain thus a plate 9, visible in FIG. 3, the length of which is defined by the distance traveled by the conveyor belt between two cutting operations, that is to say, according to the invention, by the distance traveled by the belt conveyor between two consecutive thinning operations 8. This plate 9 therefore has two thinned transverse edges 10. Preferably, the cutting device is adjusted so that the knife 9 cuts the preform 5 approximately in the middle of the thinning operation 8.

The size of each thinning 8 depends on the dimensions of the slat 6. The latter is generally a parallelepiped whose thickness is generally between 0.5 and 4 mm, preferably between 1.5 and 4 mm. Its width is generally between 5 and 20 cm and its length is at least approximately equal to the width of the preform 5 (possibly reduced by the width of the longitudinal “tape” bands present if necessary), but in general greater in order to be able to grasp it to remove it from beneath the preform 5. In addition, it is desirable that the slat 6 be of a length greater than the width of the preform 5, so as to project from it, which can facilitate its removal.

The material of the slats 6 does not matter, as long as it allows these slats to resist the weight of the thickness of preform 5 which is located above each slat 6. It can therefore be a plastic material, wood , metal, paper, cardboard, etc. with good wear resistance and stability over time. The slats can be obtained by cutting from a continuous strip from a roll.

According to a preferred embodiment of the invention, the method which has just been described complements a known method for manufacturing plasterboards having two thinned longitudinal edges. The latter generally provides for the installation of a strip, generally made of plastic, generally called a "tape", on each longitudinal side of the conveyor belt 7. Such a process is described for example in European patent application No. 482,810 This therefore makes it possible to obtain a plate based on hydraulic binder 11 as illustrated in FIG. 4, having, in addition to its two thinned transverse edges 10, two longitudinal thinned edges 25, ie in total four thinned edges.

It goes without saying that if the frequency of cutting operations is the. double that of the introduction of the slats 6, plates with 3 thinned edges are obtained (two longitudinal and one transverse).

The length of the plasterboard produced depends, of course, on the speed of movement of the conveyor belt and the frequency of the cutting operations.

The frequency of cutting operations is generally directly related to the frequency of insertion of the slats, because it is generally sought to obtain plates having two thinned transverse edges.

Thus, the method according to the invention is very flexible, because to change the length of the plates produced, it suffices simply to modify the frequency of introduction of the slats.

According to an advantageous variant illustrated in FIG. 5, the method according to the invention further comprises an intermediate step in which an impression 12 of the preform 5 is produced opposite the place where it is planned to introduce the batten 6 and / or an imprint 12bis at the place where it is planned to introduce batten 6.

This makes it possible to compensate for the localized excess thicknesses which may possibly form in the preform 5, due to the displacement of material, when the slat 6 has a large dimension.

The 12 or 12bis impression can be made by any means, for example, by following the teachings of American patents No. 2,991,824 or 4,781,558.

It is also possible to provide for the presence of a straightener 4bis of the conventional type downstream from the place where the slat 6 is introduced.

The conveyor belt 7 may possibly have been sanded and / or waxed, for example using a mineral oil. In this regard, reference can be made to the Japanese patent application published on May 10, 1978 under the number JP 53051227, which proposes to coat a conveyor belt using a silicone mineral oil.

Hydraulic binder plate manufacturing line

FIG. 6 shows a part of a production line for plates based on hydraulic binder implementing the method according to the invention.

We can therefore see a slatted magazine 20 formed of a horizontal rectangular surface 21 from the corners of which rise vertically and in parallel, four angular pieces 22, in the form of angle iron and turned towards each other, so as to frame a stack of slats 23. The dimensions of this slat magazine 20 are such that it can store a large number of slats 23 (see also Figures 7 and 8).

The horizontal surface 21 of the slat magazine 20 is supported by feet 24.

At the first batten 23, that is to say the one located at the very bottom of the stack, two cylinders 26 are arranged in parallel, which are oriented so as to extract the first batten 23 from the stack by pushing and sliding it to an inclined plane 27 consisting of a downwardly inclined surface 28 and a flange 29 at its lower part to retain the slat which has just been extracted and guide it later.

At the transverse side 30 of the inclined plane 27, that is to say the side opposite the conveyor belt 7, a cylinder 31 is arranged parallel to the longitudinal axis of the inclined plane 27, so that the actuation of this jack 31 can give an impetus to the slat which has just been extracted from the slat magazine 20. The slat thus propelled can then move by sliding parallel to the longitudinal axis of the inclined plane 27, the flange 29 of which guides it , towards a second inclined plane 32 which extends the first inclined plane 27, on the transverse side opposite to the side 30. This second inclined plane 32 also consists of an inclined surface 33 provided with a flange 34 at its lower part. It further comprises a stop 35 at its end opposite to the jack 31, this stop being generally made up of a pneumatic shock absorber and being intended to stop the movement of the slat propelled by the jack 31. The flange 34 is provided with openings 36 in front of which are arranged two jacks 37 oriented so as to propel the batten positioned on the second inclined plane 32 upwards of the inclined surface 33.

The first inclined plane 27 and the second inclined plane 32 are supported by feet, respectively, 38 and 39.

According to a variant visible in FIG. 9, a flat surface 40 is provided parallel to the surface 23, between this last and the first inclined plane 27 for horizontally supporting a slat extracted from the slat magazine 20 before its descent on the inclined surface 28 of the first inclined plane 27. Thus, as can be seen in FIG. 10, the height of the feet 24, 35 and 36 is chosen such that a slat positioned on the second inclined plane 32 is situated at a height less than that of the preform 5. In general: - the longitudinal axis of the flange 34 of the second inclined plane 32 is perpendicular to the longitudinal axis of the conveyor belt; - The means 32, 33, 34, 35 for supporting the displaced batten are located opposite the start of the conveyor belt 7; and the inclined surface 33 of the second inclined plane 32 is adjacent to the conveyor belt 7. The length of the second inclined plane 32 is at least equal to that of the slat 23, that is to say at least equal, and preferably greater than the width of the preform 5. In this way, as can be understood with reference to FIG. 10, when the jacks 37 are actuated, the batten located on the second inclined plane 32 is pushed upwards. the inclined surface 33, that is to say towards the conveyor belt 7 and the preform 5, and it is wedged between the latter and driven by them.

The difference between the length of the slat and the width of the preform 5 makes it possible to grip the slat and remove it once the plaster composition has hardened.

The production line according to the invention generally comprises electronic means which control its operation and make it possible, if necessary, to control between them the implementations of different operations.

These electronic means provide that after the introduction of a slat in the preform by actuation of the jacks 27, the jack 31 is actuated to introduce a new lath on the second inclined plane 32, then the jacks 26 are actuated to introduce another batten on the foreground tilted 27, and so on. Electronic means can vary the frequency of these operations to reduce or increase the length of the plasterboard with thinned edges produced. For the implementation of the advantageous variant of the method illustrated in FIG. 5, the production line further comprises a device making an imprint 12. The electronic means controlling the production line according to the invention are then adjusted with the electronic means controlling the device making the impression 12, so that each slat is introduced under the plate based on hydraulic binder on the side of the preform 5 opposite the place where an impression 12 is located, as can be see it in figure 10.

Device according to the invention The means 20 to 22 and 24 to 39 which have just been described can be combined into a device according to the invention.

The main advantage of such a device is that it can be installed near a conventional manufacturing line for plates based on hydraulic binder with which it can then cooperate in order to implement the method according to

1 invention.

Claims

1. A method of manufacturing a plate based on hydraulic binder (9,11), with thinned edges (10), in which: 1) is poured over a facing material (1) supported by a conveyor belt, (7 ) a hydraulic binder composition (2) so as to obtain a preform (5),

2) the hydraulic setting of the hydraulic binder composition (2) is allowed to take place, and 3) the preform (5) is cut, this process being characterized in that a) it further comprises the following steps:

- Before step 2), a slat (6,23), the length of which is at least approximately equal to the width of the preform (5), is introduced under the preform (5);

- After step 2), said slat (6,23) is removed; and in that b) the cutting of step 3) is carried out at the level of the thinning (8) created by the slat (6,23).

2. Method according to claim 1, characterized in that the cutting of step 3) takes place after the removal of the slat (6,23).

3. Method according to claim 1 or claim 2, characterized in that the cutting of the plate based on hydraulic binder is carried out approximately in the middle of the thinning (8).

4. Method according to one of claims 1 to 3, characterized in that said slat (6.23) has a thickness ranging from 0.5 to 4 mm, preferably from 1.5 to 4 mm.

5. Method according to one of claims 1 to 4, characterized in that said slat (6,23) has a width between 5 and 20 cm.

6. Method according to one of claims 1 to 5, characterized in that the conveyor belt (7) supports on each of its longitudinal sides, two lateral bands.

7. Method according to one of claims 1 to 6, characterized in that it further comprises an intermediate step in which an impression is made (12) opposite the place where it is intended to introduce the batten (6,23) and / or an imprint (12bis) at the place where it is planned to introduce this batten (6,23).

8. Method according to one of claims 1 to 7, characterized in that it further comprises, between step 1) and step 2), a step of covering the hydraulic binder composition (2) at by means of a second facing material (3).

9. Method according to one of claims 1 to 8, characterized in that the hydraulic binder comprises plaster.

10. Production line for plates based on hydraulic binder, having thinned edges, from a preform (5) comprising a facing material (1) covered with a composition of hydraulic binder (2), this line of production comprising a conveyor belt (7) and, near this conveyor belt (7), means (20-22, 24- 39) for introducing, between the preform (5) and the conveyor belt (7) batten (6,23) whose length is at least approximately equal to the width of the preform (5).

11. A production line for hydraulic binder plates according to claim 10, comprising:

- a slatted store (20),

- at least one slat (23); - means (26) for extracting one slat (23) at a time from the slat magazine (20); - Means (27,28,29) for receiving the extracted slat (23);

- means (31) for moving the extracted slat (23) in a direction parallel to its length;

- means (32,33,34,35) for supporting the displaced batten in an inclined position; and

- Means (37) for moving the slat (23) moved in a direction parallel to its width, so as to introduce it between the preform (5) and the conveyor belt (7).

12. A production line for plates based on hydraulic binder according to claim 11, in which:

- The means (27,28,29) for receiving the extracted batten (23) comprise an inclined surface (28) provided at its lower part with a flange (29);

- The means (32,33,34,35) for supporting the displaced batten (23) in an inclined position comprises an inclined surface (33) provided at its lower part with a flange (34) and on one side of a stop (35).

13. A production line for plates based on hydraulic binder according to claim 12, in which:

- The longitudinal axis of the rim (34) is perpendicular to the longitudinal axis of the conveyor belt (7); - The means (32,33,34,35) for supporting the displaced batten (23) are located opposite the start of the conveyor belt (7); and the inclined surface (33) is adjacent to the conveyor belt (7).

14. Production line for plates based on hydraulic binder according to one of claims 10 to 13, further comprising a device for making an impression (12) opposite the place where it is intended to introduce the lath

(6,23) and / or an imprint (12bis) at the place where it is planned to introduce this slat (6,23).

15. Production line for plates based on hydraulic binder according to one of claims 10 to 14, characterized in that it further comprises means for covering the composition of hydraulic binder (2) by means of a second facing material (3).

16. Production line according to one of claims 10 to

15, characterized in that the hydraulic binder comprises plaster.

17. Production line according to one of claims 10 to

16, characterized in that the conveyor belt (7) has been sanded and / or waxed.

18. Device for the introduction of slats (6,23) on a conveyor belt (7), comprising:

- a slat store (20);

- at least one slat (23);

- means (26) for extracting one slat (23) at a time from the slat magazine (20);

- Means (27,28,29) for receiving the extracted slat (23);

- means (31) for moving the extracted slat (23) in a direction parallel to its length; - means (32,33,34,35) for supporting the displaced batten in an inclined position; and

- Means (37) for moving the batten (23) moved in a direction parallel to its width.

19. Device according to claim 18, characterized in that: