EP0287447B1 - Process and apparatus for removing longitudinal steel reinforcement strips from plates with a liquid binder prior to its setting - Google Patents

Description

The present invention relates to a method and a device making it possible to extract at will longitudinal strips arranged in the mass of fresh plates based on hydraulic binder, in particular in fiber cement, leaving a manufacturing machine.

It should first of all be recalled that the technique of placing longitudinal strips of plastic reinforcement inside a profiled plate has been known for a very long time as illustrated by documents FR-A-935.006 and FR-A -964,883. However, despite the definite interest in this type of product described in particular in documents FR-A-736.561, FR-A-923.935, FR-A-1.035.214 and IT-A-22.359 B / 77, we hitherto encountered the problem of recovering, without interrupting the manufacturing cycle, the strips in the newly produced defective plates.

In fact, during the manufacture of fresh fiber cement sheets, feelers measure the thickness of the product obtained and, as soon as this thickness is judged to be outside the norm, the product is extracted from the conventional finishing cycle, then directed to a dissolver waste where the material is crushed and treated to be reintegrated as additional raw material in the tanks of the manufacturing machine. This operation, simple in the presence of easily dispersible elements and of smaller dimensions (fibers and cement), turns out to be impractical when plastic strips are present in the plate. In fact, once they have fallen into the shredder, these strips are wound either around the shaft of the shredder's turbine, creating disturbances by unbalance effect, or around the pump rotor with risk of seizing for the latter. . In addition, the strips may block the exhaust pipes by fouling.

The subject of the invention is precisely a process and device for extracting the strips from the fresh plates deemed to be defective, at the outlet of the manufacturing machine, in order to allow the recycling of the material constituting the plates, as is usually practiced in the case of plates devoid of frame.

• immobiliser la plaque sur le transporteur;
• saisir les feuillards mécaniquement approximativement au milieu de la plaque;
• soulever les feuillards jusqu'à une distance suffisante pour les séparer de la plaque; et
• évacuer les feuillards sur un côté de la plaque.

To this end, a method is proposed for separating longitudinal reinforcing strips from a fresh non-stiffened plate based on hydraulic binder resting approximately horizontally on the conveyor, characterized in that it consists in:

• immobilize the plate on the conveyor;
• mechanically grasp the strips approximately in the middle of the plate;
• lift the straps to a sufficient distance to separate them from the plate; and
• evacuate the strips on one side of the plate.

In order to grip the strips, each of them can in particular be pinched individually by a gripping tool.

Preferably, the strips are raised by applying unevenly distributed tensile forces to them, which makes it possible to remove them from the material constituting the plate, avoiding the lifting of the latter by peeling effect.

In a preferred embodiment of the invention, the lifting of the strips can thus be carried out in two stages. In a first phase, tensile forces are exerted on the strips which gradually decrease from one side to the other of the plate. During this first phase, it is advantageous to maintain the plate in order to prevent it from lifting. In a second phase, the distribution of forces is reversed and tensile forces are exerted on the strips which gradually increase from side to side of the plate. At the end of this second phase, the strips are lifted to a distance of about one meter above the plate.

In order to facilitate the release of the strips from the material constituting the plate, it is advantageous to ensure a linear translation of the plate on the conveyor, while continuing to lift the strips, when the latter have been brought to a distance of at least minus about 40 cm above the plate.

The invention also relates to a device allowing the implementation of the method described above.

This device is characterized in that it comprises a tool-carrying arm arranged transversely above the plate and supporting gripping tools in number equal to the number of strips to be extracted, means for actuating gripping tools for grasp a strip using each tool, means for moving the tool arm away from and closer to the plate and means for moving the tool arm on one side of the plate.

In a particular embodiment of the invention, the tool-carrying arm is articulated by a horizontal axis on one end of a horizontal bar, the opposite end of which is slidably mounted on a vertical guide arranged next to the conveyor, the means for moving the tool-holder arm away from and closer to the plate, comprising means for pivoting said arm around the horizontal axis and means for sliding the horizontal bar on the vertical guide. Thanks to this arrangement, the tool-holding arm is pivoted by about 25 ° around its axis of articulation on the horizontal bar, so as to extract mainly, in a first time, the strips furthest from this axis, then the horizontal bar is moved upwards by gradually bringing the tool-holder arm in alignment with the latter, so as to mainly extract, in a second step, the strips closer to the axis of the arm.

In order to move the tool-carrying arm on one side of the plate when the lifting of the strips is finished, means are advantageously provided for pivoting the horizontal bar around a vertical axis adjacent to the end of this bar which slides on the vertical guide.

Preferably, each gripping tool comprises a hook and a claw. The hooks are of substantially semi-circular shape and they are articulated on the tool-carrying arm so that they can be actuated simultaneously. In addition, their free end is sharpened in the shape of a point, in order to be able to penetrate more easily into the material of the plate. The claws are ordered separately and ensure both the pinching of the strips on the hooks and the cleaning of the latter.

Advantageously, an anti-lifting device can be applied to the plate to maintain the latter on the conveyor during the lifting of the strips. This device comprises parallel pads, arranged longitudinally and mounted under the horizontal bar between the gripping tools, preferably by means of means making it possible to adjust the spacing between the pads.

• la figure 1 est une vue de côté schématique, en élévation, d'une machine de fabrication de plaques renforcées par des feuillards et d'un dispositif d'extraction des feuillards conforme à l'invention;
• la figure 2 est une vue de face du dispositif d'extraction;
• la figure 2a est une vue de détail suivant la flèche F de la figure 2;
• la figure 3a est une vue en perspective représentant un outil de préhension du dispositif d'extraction;
• la figure 3B illustre de façon schématique le fonctionnement de l'outil de préhension de la figure 3A, en quatre étapes référencées a à d;
• les figures 4 et 5 sont des vues de face illustrant schématiquement le principe du fonctionnement de l'ensemble barre/bras porte-outils supportant les outils de préhension, lors des opérations d'extraction des feuillards;
• la figure 6 est une vue de face illustrant schématiquement le dispositif d'extraction lors du dégagement complet des feuillards;
• la figure 7 est une vue comparable à la figure 6 illustrant le dispositif d'extraction en position de relâchement des feuillards; et
• la figure 8 est une vue comparable à la figure 3A illustrant une variante de réalisation dans laquelle le dispositif d'extraction comporte un dispositif anti-soulèvement.

The invention will be better understood on reading the description below and the attached drawings showing a non-limiting example of embodiment of a device implementing the method of separating strips of longitudinal reinforcement in fiber sheets - fresh cement. In these drawings,

• Figure 1 is a schematic side view, in elevation, of a machine for manufacturing plates reinforced with strips and a strip extraction device according to the invention;
• Figure 2 is a front view of the extraction device;
• Figure 2a is a detail view along arrow F of Figure 2;
• FIG. 3a is a perspective view showing a tool for gripping the extraction device;
• Figure 3B schematically illustrates the operation of the gripping tool of Figure 3A, in four steps referenced a to d;
• Figures 4 and 5 are front views schematically illustrating the principle of operation of the bar / tool holder arm assembly supporting the gripping tools, during strip extraction operations;
• Figure 6 is a front view schematically illustrating the extraction device during the complete release of the strips;
• Figure 7 is a view comparable to Figure 6 illustrating the extraction device in the release position of the strips; and
• Figure 8 is a view comparable to Figure 3A illustrating an alternative embodiment in which the extraction device comprises an anti-lifting device.

FIG. 1 shows the path followed by a corrugated fiber-cement plate reinforced with longitudinal polypropylene strips, at the outlet of a dehydration manufacturing machine. The fresh plate from a cylinder 1 for shaping the machine is unrolled on a rubber conveyor 2, approximately horizontal. It then passes under feelers of thickness (not shown) which control the elimination of the plates judged to be defective. Once detected, the defective plate 3, not yet stiffened, is sent to a device 4 for extracting the strips according to the invention. When the middle of the plate 3 is positioned approximately plumb with an extraction assembly 5 of the extraction device 4, the conveyor 2 is stopped, in order to allow the assembly 5 to take off the strips 6. This Once this phase has been carried out, the plate 3 resumes its linear progression towards a waste dissolver 7, while the extraction assembly 5 continues the movements making it possible to completely separate the strips from the plate 3.

As shown in FIG. 2, the assembly 5 making it possible to extract the strips 6 from the fiber cement plate 3 comprises a number of gripping tools 8 equal to the number of strips to be extracted (one strip per wave). The gripping tools 8 are mounted on a tool-carrying arm 12, one end of which is articulated by a hinge pin 10 at one end of a horizontal bar 11. At its opposite end, the horizontal bar 11 is slidably supported by a vertical guide 14 which rests on the ground next to the conveyor 2, by means of a device 19, such as a jack or a geared motor, making it possible to control the rotation of the assembly constituted by the support arm tools 12, the horizontal bar 11 and the guide 14 around the vertical axis 13 of the latter.

The guide 14 is arranged in a vertical plane oriented transversely relative to the conveyor 2 and in which the latter is interrupted as illustrated in FIG. 2a. It is thus possible, by actuating the device 19, to bring the assembly extraction 5 in a transverse position, above the interruption formed in the conveyor 2, in order to grip the strips 6 in the part of the plate 3, then to extract them by lifting them above this plate .

In the embodiment shown, the pivoting of the tool-carrying arm 12 around the articulation axis 10 is controlled by a pneumatic cylinder 16 interposed between the arm 12 and the horizontal bar 11. Furthermore, the sliding of this the latter along the vertical guide 14 is controlled by an electric motor 18 actuating a vertical endless screw 17 linked to the guide 14 and engaged on a screen linked to the bar 11.

As illustrated more clearly in FIG. 3A, each of the gripping tools 8 comprises a hook 9, preferably made of thin steel, which has a substantially semi-circular shape in the plane of the arm 12, and the end of which is tapered to form a point facilitating its entry into the plate. Each hook 9 is articulated on the tool-carrying arm 12 by an axis 9a perpendicular to the latter. A pneumatic cylinder 15 (FIG. 2) supported by the arm 12 simultaneously controls the pivoting of all the hooks 9 around their axes 9a by means of a rod 15a (FIG. 3A).

Each gripping tool 8 furthermore comprises a claw 20 mounted on the tool-carrying arm 12 by means of a pneumatic microverin 21. The claw 20 is arranged in the plane of the corresponding hook 9 and the actuation of the microverin 21 allows to apply the claw against the hook, as illustrated in FIG. 3B d, to pinch the strip 6 between these two members, when the hook 9 has pivoted about its axis 9a under the action of the jack 15.

When a plate 3 deemed to be defective is parked under the extraction assembly 5, the tool-carrying arm 12 is initially horizontal and each gripping tool 8 is arranged vertically above a strip 6 of the plate 3 (FIG. 3Ba). The bar 11-tool holder 12 assembly is then lowered by rotation of the worm 17, so as to cause the perforation of the plate by the ends of the hooks 9 (FIG. 3Bb). The jack 15 then causes the simultaneous rotation of all of the hooks 9 which come to grip the strips 6 by surrounding them from below (FIG. 3Bc). These are then raised upwards and obliquely by a pivoting movement of the tool-carrying arm 12 around its axis 10, then by a translational movement of the bar 11 accompanied by a rotation in the opposite direction. of the arm 12. As the strips are brought above the plate, the claws 20 are actuated by the micro-jacks 21 to pinch each strip 6 in each hook 9 (FIG. 3Bd), so as to avoid accidental slippage of one or other of the strips during subsequent linear translation operations and then of permanent elimination of the strips from the production line (Figures 6 and 7).

In Figures 4 and 5, there is shown more particularly the operating principle of the bar assembly 11-tool holder arm 12. It is noted that once the strips 6 surrounded by the hooks 9 the initial movement carried out on the strips aims to remove these from the plate. This movement is obtained first of all by an upward rotation of the tool-carrying arm 12, at an angle of approximately 25 °, controlled by the jack 16 around the articulation axis 10. The arm 12 rises thus above the fresh plate so as to achieve the correct bursting of the material and avoid lifting of the latter by peeling effect. This first rotation causes, as shown in FIG. 4, the extraction mainly of the strips 6 furthest from the axis 10, by exerting extraction forces which decrease progressively towards the latter.

As shown in Figure 5, the extraction is completed in a second step by the combined action of an upward translation of the bar 11 moved by the screw 17 and a return to the horizontal of the support arm tools 12. This second series of movements this time mainly extracts the strips 6 closest to the axis of rotation 10, by exerting extraction forces which progressively increase towards the latter. When this second phase of lifting the strips is completed (FIG. 5), the upward translation of the bar 11 continues up to a distance of approximately 1 m above the fresh plate (FIG. 6).

Preferably, when the strips have been brought to at least about 40 cm above the plate, the conveyor 2 is restarted to accelerate the tearing of the strips.

The device 19 then ensures, as shown in FIG. 7, the pivoting of the bar 11-tool holder arm 12 assembly until this assembly is entirely offset on one side of the conveyor 2 and of the plate 3 , for example above a tank 25. The strips are then released by actuating the cylinders 15 and 21 in the opposite direction. The said assembly is then returned to its initial position above the conveyor, where it is then ready to be lowered to process a new defective plate.

FIG. 8 shows another embodiment of the invention in which, in order to avoid lifting the plate 3 during the successive tearing of the strips 6 by the hooks 9, an anti-lifting device is fixed under the horizontal bar 11.

In the nonlimiting example shown in FIG. 8, the anti-lifting device comprises a series of parallel pads 22, produced in flat bars, fixed under the bar 11 in the direction of travel of the plates, between the strips 6. The pads 22 partially cover the plate in the areas devoid of strips and are fixed to the bar 11 by an adjustment system comprising an oblong opening 24 making it possible to adjust the spacing between the pads. A notch 23 is formed on each shoe 22, in line with the hooks 9, to allow the latter to pivot in the direction of the plate.

In another embodiment (not shown), the strips are gripped by a system of cables mounted on pulleys, actuated by a winch and tensioned by a counterweight. The implementation of the winch makes it possible to simultaneously encircle all the strips and to lift them up to a mandrel situated for example approximately 60 cm above the center of the plate. A gripper carried by an articulated arm then grasps all the strips to bring them to the side of the plate and reject them.

Thus, in accordance with the method and the device according to the invention, it is possible without manual intervention and without significant disruption of the manufacturing cycle of the fiber cement sheets reinforced with longitudinal strips, to eliminate the defective sheets and to extract the strips therefrom. , which allows the traditional recovery of the fiber-cement matrix by grinding and treatment in the dissolver.

Claims (16)

1. Process for separating longitudinal reinforcing strips from a fresh, unrigidified, hydraulic cement-based plate resting approximately horizontally on a conveyor (2), characterized in that it comprises immobilizing the plate on the conveyor (2), mechanically grasping the strips (6) approximately in the centre of the plate, raising the strips (6) to an adequate distance for separating them from the plate and removing the strip (6) on one side of the plate.

2. Process according to claim 1, characterized in that the strips (6) are raised by exerting thereon unequally distributed tensile stresses.

3. Process according to claim 2, characterized in that the strips (6) are raised by exerting, in a first phase, tensile stresses progressively decreasing from one side to the other of the plate and then, in a second phase, tensile stresses progressively increasing from one side of the plate to the other.

4. Process according to claim 3, characterized in that at least during the first raising phase of the strip (6), the plate is held in order to prevent the raising thereof.

5. Process according to one of the claims 1 to 4, characterized in that, when the strips (6) have been raised by at least approximately 40 cm above the plate, one continues to raise the strips (6), whilst ensuring a linear translation of the plate on the conveyor (2).

6. Process according to one of the claims 1 to 5, characterized in that the strips (6) are grasped by gripping each of them individually.

7. Process according to any one of the claims 1 to 5, characterized in that the strips (6) are grasped by encircling them all simultaneously.

8. Apparatus for separating longitudinal reinforcing strips from an unrigidified, fresh plate resting approximately horizontally on a conveyor (2), characterized in that it comprises a tool-holding arm (12) positioned transversely above the plate and which supports gripping tools (8) in the same number as there are strips (6) to be extracted, means (15) for actuating the gripping tool in order to grasp a strip (6) with the aid of each tool, means (16-18) for displacing the tool-holding arm (12) away from and towards the plate and means (19) for displacing the tool-holding arm (12) on one side of the plate.

9. Apparatus according to claim 8, characterized in that the tool-holding arm (12) is articulated by a horizontal shaft (10) on one end of a horizontal bar (11), whose opposite end is slidingly mounted on a vertical guide (14) positioned alongside the conveyor (2), the means for moving the tool-holding arm (12) towards and away from the plate being constituted by a means (16) for pivoting said arm about the horizontal shaft (10) and a means (17-18) for sliding the horizontal bar (11) on the vertical guide (14).

10. Apparatus according to claim 9, characterized in that the means (19) for displacing the tool-holding arm (12) on one side of the plate are means for pivoting the horizontal bar (11) around a vertical shaft adjacent to the end of said bar slidingly mounted on the vertical guide (14).

11. Apparatus according to any one of the claims 8 to 10, characterized in that each gripping tool comprises a hook (9) articulated on the tool-holding arm (12), the tool actuating means (15) simultaneously controlling the pivoting of all the hooks (9).

12. Apparatus according to claim 11, characterized in that the hooks (9) are substantially semicircular and have a three pointed end.

13. Apparatus according to either of the claims 11 and 12, characterized in that each gripping tool also comprises a grip (20) controlled by an actuating means (21), so as to permit the nipping of a strip on the hook (9) of said tool.

14. Apparatus according to any one of the claims 8 to 13, characterized in that it also comprises an anti-raising device (22) which can be applied to the plate (3).

15. Device according to claim 14, combined with claim 7, characterized in that the anti-raising device comprises longitudinally positioned parallel supports (22) and mounted beneath the horizontal bar (11) between the gripping tools (8).

16. Apparatus according to claim 15, characterized in that means (24) are provided for regulating the spacing between the parallel supports (22).

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