EP0610529A1 - Process and device for making exact-sized panel-shaped elements - Google Patents

Abstract

In the making of large-format thin panel-shaped elements from a material which sets and is pourable during processing, in particular gypsum, by the discharge method, movable cores (14) are used, by which the mould chambers (11) are subdivided into mould subchambers (15) after the casting slurry has been poured in. Following setting, the panel-shaped elements are discharged together with the movable cores (14) from the mould subchambers (15). <IMAGE>

Description

The invention relates to a process for the production of precisely dimensionally stable plate-shaped elements from a setting material which can be cast during processing, in particular gypsum, in which the material is poured in the form of a slurry into at least one molding chamber and then closed in a shape-retaining manner and the casting slurry in the molding chamber at least as long is allowed to set until the elements formed therefrom are dimensionally stable, whereupon the elements are ejected from the molding chamber which is then open on one side and fed to a further treatment.

In addition, the invention relates to a device for carrying out this method with an open-top molding box containing at least one molding chamber delimited by pairs of parallel walls, which is closed at the bottom by strip-shaped closing means which are displaceably mounted in the molding chamber and connected to an ejection device which are movable between a lowered end position and a raised ejection position.

For example, partition walls made of gypsum according to DIN 18 163 are prefabricated gypsum building elements for the construction of light partition walls. They typically have a format of 500 x 666 mm with a thickness of 40 to 100 mm and are provided with precisely fitting grooves and tongues all around, so that the panels can be moved or assembled using the adhesive process. The plates are cast in rigid mold boxes, the mold chambers of which are formed by walls with a corresponding surface quality (mirror hard chrome plating). After the gypsum slurry has set, the panels are ejected from the molding chambers.

Since gypsum is dimensionally stable, the components manufactured in this way have an accuracy that is given by the accuracy of the molding chambers. It is ± 0.02 to 0.05 mm in all dimensions, with an absolutely flat and smooth surface.

Thanks to this accuracy, the partition wall panels automatically result in a straight wall during installation, due to which the smooth surface means that plastering is no longer necessary, which means that painting or wallpapering work can be started immediately after moving the partition wall panels.

A method and a device for producing such precisely dimensionally stable plate- or block-shaped elements, In particular made of plaster, are described for example in EP 0 294 508 B1.

In practice, plate-shaped components, for example plaster ceiling tiles, are also common, which are distinguished by a much smaller thickness compared to their dimensions. Such ceiling tiles are used as so-called suspended ceiling elements, whereby they are used not only for ceiling cladding or ventilation ceilings because of their very good optical, sound and heat-insulating properties and their aesthetically pleasing exterior, but whenever the important thing is the representative character of a room to underline. The dimensions of such decorative plaster ceiling tiles are typically 500 x 500 mm or 600 x 600 mm or 1000 x 500 mm with thicknesses of 15 to 40 mm. They are all provided with all-round grooves and tongues.

These relatively thin plate-shaped components are still often manufactured more or less manually in flat-lying molds because it is not possible to produce these components, such as the aforementioned standardized partition wall panels, with the required high precision using the so-called ejection process. The setting of the gypsum (hardening or recrystallization) is an exothermic process that is accompanied by swelling, which means that the gypsum expands when setting, whereby the extent can be up to 3 percent by volume depending on the provenance. In order to prevent this uncontrolled expansion when setting, taking into account the required high precision of the finished components, molded boxes must be used which, as a closed system, are characterized not only by the highest accuracy but also by great stability. A 50 x 100 cm partition wall plate can develop a compressive force of up to 200 kN as swelling force when tied.

The swelling forces that occur are balanced within the molding box; however, they must be absorbed by the outer bulkhead plates (end plates). Despite the surfaces of all mold chamber parts being polished to a mirror finish, the swelling forces that occur when the gypsum sets, result in very large frictional forces that have to be overcome when the set gypsum boards are ejected from the mold chamber. These frictional forces obviously occur primarily on the surfaces and less on the tongue and groove profile sides.

With a partition wall made of plaster in normal format (500 x 666 mm), ejection forces in the order of 120 to 150 kN can be necessary if the plaster slurry is allowed to set completely in the molding chamber. However, to achieve the highest possible productivity of the gypsum board molding machine, the boards are as early as possible, i.e. ejected in a relatively soft condition. The plates then have a hardness of approx. 10 to 15 Shore C, which, in comparison, corresponds to the hardness of butter in the cooled state. But even in this relatively soft condition, 20 to 39 kN of ejection force is still required for a single 500 x 666 mm plate.

The ejection forces exerted in known plasterboard molding machines, as a rule by correspondingly strongly dimensioned hydraulic cylinders on the lower narrow side of the relatively soft plasterboard, can be absorbed by the plasterboard only if the thickness of the plates does not fall below a certain minimum value in relation to the other plate dimensions. For the aforementioned plasterboard partition walls (500 x 666 mm, thickness 40 to 100 mm) this condition is met, so that the production of these gypsum boards after the ejection process is not a problem.

However, the larger the format and the smaller the thickness of the gypsum board, the more difficult or even impossible it is to manufacture such boards with the required precision after the ejection process. The ejection forces acting on the thin plates lead to compression or breakage.

This problem is known and is described, for example, in EP 0 161 374 B1. To remedy this, a process for the production of large-area thin building boards made of gypsum in the ejection process is specified, in which the mold box containing the molding chamber is relaxed at the time the boards are ejected. For this purpose, the molding box is first compressed in the horizontal direction by means of hydraulic cylinders with a force which ensures that the molding box reliably absorbs the pressure of the building boards which expand as they solidify. After the building boards have solidified, the mold box is released from the hydraulic clamping cylinders, whereupon the boards are ejected.

By relaxing the mold box, the frictional forces occurring between the set plates and the mold chamber walls are reduced, but the still soft plates lose the desired precision of their dimensions due to the relaxation of the mold box because they can swell. The dimensional accuracy of the mold chambers also deteriorates with the constant opening and closing of the mold box because gypsum can enter between the tongue and groove profiles and the bulkhead plates.

In the case of mold boxes for plates of large format and small thickness, it is also inevitable that greater turbulence will occur in the casting slurry when the molding chambers are loaded, so that air inclusions are present in the casting slurry. In the case of thin panels, this leads to the formation of voids, which makes the panels unusable.

Building boards of large format and small thickness are also usually reinforced by fibers (e.g. glass fibers), which means that the pouring paste is much more viscous than normal gypsum paste at the time the mold box is filled because of this fiber admixture. This favors the appearance of voids in the thin plates.

The object of the invention is therefore to remedy this situation and to point out a way which, in comparison with its small thickness, makes it possible to produce large-format plate-shaped elements made of castable material, in particular gypsum, in a simple and reliable manner in the ejection process with high precision.

To achieve this object, in the above-mentioned method, the procedure according to the invention is such that the molding chamber is subdivided into partial mold chambers by at least one movable core which acts in the manner of a partition and that the elements formed in the partial mold chambers after setting together with the core adjacent to them ejected from the molding chamber and then separated from the core before they are sent for further treatment.

Because of the use of the movable plate-shaped cores, several elements are produced simultaneously for each molding chamber. In particular in the production of gypsum boards, one movable core per molding chamber is generally used, ie it always takes place at the same time the production of two plasterboards per molding chamber.

Since after the casting slurry has set, the movable cores with the thin plate-shaped elements which are in contact with them on the broad side are ejected at the same time, the frictional forces acting on the plate-shaped elements during ejection are reduced by approximately 50%. In addition, the adhesion between the elements and the respectively assigned core during ejection brings about a relief of the end face of the still soft elements receiving the ejection forces, while at the same time the movable strip-shaped closure elements of the molding chamber which transmit the ejection forces are also relieved accordingly. This ensures that the shaped plate-shaped elements do not suffer any deformation when ejected, despite their relatively small thickness.

In a preferred embodiment, when the respective molding chamber is filled, each movable core is in a retracted filling position which at least partially leaves the molding chamber open; after pouring a corresponding amount of casting slurry into the molding chamber, it is moved into an operating position that divides the partial molding chambers, in which it remains held until the casting slurry has set. In this filling position, the core is generally held essentially on the face side with adjacent closure means of the molding chamber, it being possible for the plate-shaped elements to be produced from the casting slurry to be given a corresponding face profile by appropriate profiling of these closure means. Moreover, it is often expedient if, at about the same time as the core is moved forward into the operating position, the closing means of the molding chamber which are adjacent to it are moved back in the opposite direction into an end position in which they remain until they set of the pouring porridge and from which they are then moved together with the core into the ejection position while ejecting the elements.

These measures ensure that when pouring the pouring slurry, the mold chamber still has its normal large cross section due to the retracted moving cores, which is dimensioned so that with the available depth and chamber width only slight turbulence occurs in the pouring slurry that does not contain air or Have voids in the plate-shaped elements to be produced and not even when the pouring slurry is viscous, for example because it contains fillers, for example glass fibers, etc.

The subsequent extension of the movable cores from the filling position into the operating position and, if necessary, the additional closing of the closing means of the molding chamber into the end position have the advantage that the pouring slurry filled into the molding chamber due to the relative movement between the respective core (and possibly the closing means) and the Mold chamber walls an additional mixing and thus ventilation of the poured poured porridge is achieved.

After the plate-shaped elements formed have set, they are ejected together with the respectively assigned core. It is advantageous if, after reaching the ejection position, the core is moved back relative to the closing means of the molding chamber by a predetermined amount before the elements are separated from the core. In this way it is achieved that the plate-shaped elements are released at one point from the core, so that they can be gripped gently at this point with appropriate gripping means. The explained moving back of the core relative to the plate-shaped elements lying against it is a Drawing process in which the elements adhere to the core even further. The remaining adhesive force is sufficient to prevent the plate-shaped elements from falling over and thus no longer being securely gripped by the gripping means.

As soon as the gripping means have securely grasped the plate-shaped elements, the cores are withdrawn entirely, so that the elements can then be handled freely hanging from the gripping means. The closing means of the molding chamber and the cores are then moved back into the filling position or the starting position, whereupon the next loading cycle of the molding chamber takes place with casting slurry.

For economic reasons, a molding box is usually used in practice, which contains a plurality of molding chambers divided by stationary parallel partition walls, each of which contains at least one movable core, the cores of all molding chambers being moved together. Basically, it is conceivable for the production of special plate-shaped elements, for example very large dimensions, that a molding box is used to carry out the method, which has only a single molding chamber, which may contain only one movable core.

A device set up to carry out the new method with the features mentioned at the outset is characterized in accordance with the invention in that at least one plate-like or disk-shaped movable core which acts in the manner of a partition and is oriented parallel to two side walls of the molding chamber is arranged in the molding chamber and through which the mold chamber can be subdivided into partial mold chambers, which are closed on the bottom side by the closing means arranged on both sides of the core, that the core with an adjusting device is coupled, by means of which it can be moved between a retracted filling position at least partially leaving the mold chambers, an operating position dividing the partial mold chambers and an advanced ejection position, and that the actuating device of the core is synchronized with the ejection device in such a way that the core during the ejection movement of the bottom closure means the molding chamber can be moved into its ejection position together with these.

The bottom-side closure means can be lowered into the end position by the ejection device, starting from the filling position, while the core can be advanced into the operating position by the adjusting device. In this way, particularly good mixing and thus deaeration of the quantity of casting slurry filled into the molding chamber is achieved.

Further refinements of the new device are the subject of subclaims.

• Fig. 1 eine Vorrichtung zur Herstellung dünner Gipsplatten gemäß der Erfindung, geschnitten längs der Linie I-I der Fig. 3 in einer Seitenansicht unter Veranschaulichung der in der Füllstellung stehenden beweglichen Kerne,
• Fig. 2 die Vorrichtung nach Fig. 1 in einer entsprechenden Darstellung unter Veranschaulichung der bei mit Gipsbrei gefüllten Formkammern in der ausgefahrenen Betriebsstellung stehenden beweglichen Kerne,
• Fig. 3 die Vorrichtung nach Fig. 2, geschnitten längs der Linie III-III der Fig. 2 in einer Seitenansicht und in schematischer Darstellung,
• Fig. 4 einen Ausschnitt aus der Vorrichtung nach Fig. 1 unter Veranschaulichung einiger Formkammern mit den zugehörigen beweglichen Kernen sowie den bodenseitigen Abschlußmitteln der Formkammern, in einer Schnittdarstellung ähnlich Fig. 1, jedoch in einem anderen Maßstab unter Veranschaulichung des Zustands beim Einfüllen des Gießbreis,
• Fig. 5 eine Bodenabschlußleiste der Abschlußmittel der Vorrichtung nach Fig. 4 im Querschnitt, in einer Seitenansicht und in einem anderen Maßstab,
• Fig. 6 bis 10 die Anordnung nach Fig. 4, in einer entsprechenden Darstellung unter Veranschaulichung des Zustandes beim Einfüllen des Gießbreis in die Formkammern, bei in die Endstellung abgefahrenen Bodenleisten während des Abbindens der Gipsplatten, bei in der Ausstoßstellung stehenden beweglichen Kernen beim Ausstoßen der Gipsplatten aus den Formkammern, beim Greifen bzw. Festhalten der Gipsplatten mittels eines Greifers im Anschluß an das teilweise Zurückziehen der beweglichen Kerne aus der Ausstoßstellung und beim Abheben der Gipsplatten von dem Formkasten mittels des Greifers.

In the drawing, an embodiment of the object of the invention is shown. Show it:

• 1 shows a device for the production of thin gypsum boards according to the invention, cut along the line II of FIG. 3 in a side view illustrating the movable cores in the filling position,
• 2 shows the device according to FIG. 1 in a corresponding illustration, illustrating the movable cores which are in the extended operating position when the mold chambers are filled with gypsum paste,
• 3 shows the device according to FIG. 2, cut along the line III-III of FIG. 2 in a side view and in a schematic representation,
• 4 shows a section of the device according to FIG. 1, illustrating some mold chambers with the associated movable cores and the bottom-side closing means of the mold chambers, in a sectional illustration similar to FIG. 1, but on a different scale, illustrating the state when filling the pouring slurry,
• 5 shows a bottom end strip of the end means of the device according to FIG. 4 in cross section, in a side view and on a different scale,
• Fig. 6 to 10, the arrangement of FIG. 4, in a corresponding representation, illustrating the state when filling the pouring slurry into the mold chambers, in the end position worn bottom strips during the setting of the gypsum boards, with moving cores in the ejection position when ejecting the Gypsum boards from the mold chambers, when gripping or holding the gypsum boards by means of a gripper following the partial withdrawal of the movable cores from the ejection position and when lifting the gypsum boards from the mold box by means of the gripper.

The device shown in FIGS. 1 to 3 has a machine base 1 with a horizontal frame 2 welded together from profiled beams, which is supported on the ground by feet indicated at 3 in FIG. 3. On the frame 2 four columns 4 are arranged, which carry two parallel horizontal supports 5, on which a rectangular shaped box 6 is attached, which is supported laterally at 7.

The molding box 6 has 2 flat side walls 8 aligned parallel to the supports 5 and two also flat end walls 9 running at right angles thereto (FIGS. 1, 3), which are screwed together. Its interior is divided by parallel to the end walls 9, such as these vertically aligned planar partition walls 10, into adjacent mold chambers 11, of which 24 are provided in the illustrated embodiment. On the inside, the two side walls 8 are provided with parallel strip-like webs or likewise parallel groove-like depressions, through which a tongue profile 12 is formed on one side and a groove profile 13 (FIG. 3) is formed on the other side. By means of these tongue and groove profiles 12, 13, gypsum boards, grooves and springs are formed on the side walls of the gypsum boards produced in the molding chambers 11.

Each of the mold chambers 11, which are rectangular in cross section, can be divided by a plate-shaped or disc-shaped thin core 14 (compare in particular FIGS. 4, 5) into two partial mold chambers 15 (FIG. 2), which have the same width and each for forming a thin plasterboard serve, which is delimited on one side by a core 14 and on the other side by a partition 10 or by one of the two end walls 9. Each of the essentially rectangular cores 14 is formed by a sheet metal, which is laterally sealed and adjoins the side walls 8 and is movably guided thereon. For each molding chamber 11, a core 14 is provided, which is aligned parallel to the partition walls 10 and sealed on the bottom of the respective molding chamber 11 between two closing means forming bottom strips 16 and is displaceably guided, which in turn can be seen in FIG. 5 with a attached centrally arranged bar 17 are formed, through which a groove is formed on the bottom narrow side of the plasterboard produced in the respective partial mold chamber 15 becomes. The strip 17 is aligned with the tongue and groove profile 12, 13 on the side walls 8 of the respective partial mold chamber 15, in such a way that the gypsum board produced has an all-round tongue and groove profile.

The cores 14, which are aligned parallel to one another and lie in vertical planes, are connected on their underside via a fork piece 18 (FIGS. 3, 4) to a tie rod 19 which is attached at the other end to a horizontal cross member 20 common to all tie rods 19 (FIG. 1). . When the crossbeam 20 moves up and down, all the cores 14 in their respective molding chambers 11 are adjusted up and down by the same stroke.

To adjust the crossbeam 20, an adjusting device is used which has two vertically aligned lifting cylinders 21 designed as telescopic cylinders, the piston rods 22 of which are articulated to the crossbeam 20 at 23.

The bottom strips 16, which extend on both sides of the core 14 in each molding chamber and which close the bottom of the molding chamber together with the core 14, are each rigidly connected via a two-part strip-like ejector 24 to a horizontal base plate 25 common to all the bottom strips 16, which is above the frame 2 is arranged adjustable in height. The base plate 25 carries two mutually spaced parallel downward hanging belts 26, so that there is an overall formation of a U-shaped cross-sectional shape. The base plate 25 is formed with through bores 27 lying in a row (FIG. 3), each of which receives a tie rod 19 which is guided in the bore 27 so as to be vertically displaceable.

On the two belts 26 there are two spaced apart, approximately trapezoidal in longitudinal section U-shaped Mounted bracket parts 28 which have on their underside a transverse flange 29 in which a lifting cylinder 21 is received (Fig. 1).

When the lifting cylinder 21 is actuated, the cross member 20 with the cores 14 is therefore adjusted in height relative to the base plate 25 and the base strips 16 connected to it.

With the base plate 25, the piston rods 30 of two hydraulic or pneumatic ejection cylinders 31 are connected, which form parts of an ejection device and are received in corresponding bores 33 of the frame 2, to which they are rigidly attached.

The ejection cylinders 31 make it possible to move the base plate 25 and thus the base strips 16 up and down in the vertical direction, as is indicated in FIG. 1, 2 by dashed arrows 34. To illustrate the vertical actuating movement of the crossbeam 20 generated by the lifting cylinders 21, solid arrows 35 are entered in FIGS. 1, 2.

All walls 8, 9, 10, 16 delimiting the molding chambers 11, like the cores 14, are hard chrome-plated and highly polished on their side facing the respective partial molding chamber 15. These parts are made of a special stainless steel.

The upward opening of the vertically aligned mold chambers 10, delimited by flat vertical walls, can be closed by a closure device after filling the gypsum paste, which, for the sake of clarity, has been omitted in FIGS. 1, 2 and only in FIGS. 3, 4 is indicated.

This closure device has two guide rods 36 which are arranged on the molding box 6 in the vicinity of its opening edge and are fastened to the two end walls 9 via bearing blocks 37. On the two guide rods 36, two parallel, so-called mask bars 38, which are connected to one another at a fixed distance, are slidably guided, to which a slide-like closure member for opening the molding box 6 is fastened, which is also referred to as a "mask" and consists of a number of sealed, parallel, parallel Mask profile strips 39 (FIG. 4), each of which has two groove-like depressions 40. The groove-like depressions 40 each serve to form a spring on the facing upper side of the plasterboard produced in the respective partial mold chamber 15. The closure member is sealed against the partitions 9 and the partitions 10 and against the side walls 8 in the region of the opening edge of the molding box.

With the closure member, two hydraulic cylinders 41 are connected, the piston rods of which are formed by the guide rods 36 and which make it possible to move the closure member from the off-center rest position shown in FIG. 3 to a front position in which the opening of the molding box 6 is completely closed , as indicated in Fig. 4.

The production of thin, large-format gypsum boards takes place with the device described so far in the following manner, reference being made to FIGS. 6 to 10 illustrating the individual process steps:

The cores 14 and the sealing strips 16 are first brought into the filling position shown in FIG. 6 by appropriate actuation of the lifting cylinders 21 and the ejection cylinders 31. In this filling position they are Cores 14 with their narrow end faces facing the respective molding chamber 10 are traversed to a depth of approximately 676 mm with respect to the opening edge of the molding box 6. This depth dimension is designated by 42 in FIG. 6. The width 43 of the mold chamber opening is 74 mm. The base strips 16 are at the same height as the narrow end faces of the cores 14 with which they are aligned.

With this setting of the movable cores 14 and the base strips 16, the conditions are exactly the same as in the production of standard gypsum boards according to DIN 18163 in the mold chambers 11 left free by the movable cores 14. From practice it is known that with a mold chamber width of 74 mm and a depth of 676 mm when filling the gypsum slurry, there is only slight turbulence, which does not result in air influences or blowholes, even if the gypsum slurry mixture contains glass fibers.

After filling the mold chambers 11 to the height 42 of 676 mm - the filling is indicated in Fig. 6 at 44 - the bottom rails 16 are moved into a lower end position, in which they are at a distance of 1,000 mm from the mold box edge, as this is indicated in Fig. 7 at 42a. At the same time, the movable cores 14 are extended in the opposite direction from the filling position into their operating position, in which they assume their normal altitude, in which they align with their upper end face with the edges of the molding box 6.

The cores 14 and the bottom strips 16 now assume the position according to FIG. 7, the previous movements of the bottom strips 16 and the cores 14 being indicated by the arrows 34, 35.

When the bottom rails 16 were moved into the lower end position and the cores 14 were extended into the operating position, the gypsum pulp filling 44 of the mold chambers 11 was additionally mixed and vented, while at the same time each mold chamber 11 was divided into two mold chambers 15 filled with gypsum pulp, of which in each a thin plasterboard is created.

After the cores 14 have been extended into the operating position, the casting slurry in the molding box 6 stands on the filling level at the opening edge of the molding box. It is now by appropriate actuation of the hydraulic cylinder 41 (FIG. 3), the closure member consisting of the mask profile strips 39 (FIG. 4) advanced with respect to FIG. 3 to the right. The opening of the molding box 6 is closed, the gypsum paste contained in the partial mold chambers 15 filling the groove-like depressions 40 of the mask profile strips 39, so that springs are molded onto the gypsum boards which form when the gypsum paste forms.

After the filled gypsum paste contained in the partial mold chambers 11 has set so far that the shaped gypsum boards are dimensionally stable (approx. 3 to 5 minutes), the closure member consisting of the mask profile strips 39 is moved back into the off-center rest position according to FIG. 3, in the mold box 6 is open. During this movement back of the closure member, the mask profile strips 39 at the same time bring about a reforming of the still soft gypsum boards on the top side facing them. This "drawing process" together with the previous casting process ensures that the shape and surface of the springs or shoulders present on the facing top of the plasterboard are absolutely smooth and complete.

As soon as the molding box 6 is opened in the manner described, the two ejection cylinders 31 (FIGS. 1, 2) take effect, which extend the base plate 25 and thus the base strips 16 together into the upper ejection position. The movable cores 14 are inevitably carried synchronously because the lifting cylinders 21 and the cross member 20 join in the movement of the base plate 25.

During this ejection movement of the base strips 16 and the movable cores 14, the thin gypsum boards 50 formed in the partial mold chambers 15 are also pushed out over the broad area of the associated core 14. Frictional forces therefore only occur during the ejection movement between a single broad side (facing a partition wall 10 or an end wall 9) and the two vertical narrow sides of the plasterboard 50 and these adjacent stationary wall parts of the molding chamber 6. In practical terms, this means that the frictional force that occurs is reduced by approximately 50% compared to the conditions that exist if a movable core 14 were not also ejected. At the same time, because of the adhesive force present between the plasterboard 50 and the adjacent moving core 14, the ejection force exerted on the narrow side of the plasterboard 50 facing the respective base strip 16 is again significantly reduced, with the result that the hardness in this state is only approx. Gypsum boards 50 having 10 to 15 Shore C do not suffer any compression or other deformation during the ejection process.

At the end of the ejection process, the gypsum boards 50 and the cores 14 and the base strips 16 assume the position shown in FIG. 8, in which the gypsum boards 50 are completely pushed out of the molding box. The gypsum boards 50 are held securely on the cores 14 assigned to them by the existing adhesion, so that they cannot tip over.

The previous movements of the cores 14 and the base strips 16 are again indicated in FIG. 8 by the arrows 34, 35.

In order to remove the plasterboard 50 from the extended cores 14, starting from the position according to FIG. 8, the cores 14 are lowered in the direction of arrow 35 into the position according to FIG. 9 by approximately 300 mm, while the base strips 16 are in their ejection position 8 remain. The lowering of the cores 14 takes place by appropriately loading the lifting cylinders 21 (FIG. 2); the ejection cylinders 31 meanwhile hold the bottom strips 16 in the position according to FIG. 8.

During this removal of the cores 14 from the plasterboards 50 standing on the base strips 16, the plasterboards 50 are still held by the existing adhesion to the cores 14, so that they cannot fall over.

After the cores 14 have reached the lowered position shown in FIG. 9 in the direction of arrow 35, the gypsum boards 50 are gripped by means of a pneumatically operated gripper 51, which from above has intermediate plates 52, the thickness of which corresponds approximately to the thickness of the cores 14, into the gaps between the plasterboards 50 released by the cores 14. After retracting the intermediate plates 52, laterally arranged pressure jaws 53 engaging on the plasterboard 50 on the broad side are pressed inwards, so that the gypsum plates 50 are gently clamped on the broad side between the intermediate plates 52 and the pressure plates 53. The basic structure of the gripper 51 is known; it is described in EP 0 161 374 B1.

After the pressure plates 53 have closed, the state according to FIG. 9 is reached.

After the gripper 51 has gripped the plasterboard 50 in the manner described, the cores 14 are pulled downwards out of the plate pack held by the gripper 51 by corresponding actuation of the lifting cylinders 21 (FIG. 2). The gypsum boards 50 now hang freely on the gripper 51 and can be fed for further treatment. The cores 14 have been moved completely back into the molding chamber 6 in the direction of the arrow 34, while the base strips 16 have been held in their position according to FIGS. 8, 9. The cores 14 thus do not hinder the removal of the gypsum boards 50.

All parts now assume the position shown in FIG. 10.

The cores 14 and the bottom rails 16 are then brought back into the filling position according to FIG. 3 by corresponding actuation of the lifting cylinders 21 and the ejection cylinders 31, with which the next loading cycle can follow.

In the above, the production of thin gypsum boards 50 in the ejection process has been described. In principle, this method can of course also be used for the production of thin, large-format plates using the ejection process from other pourable materials, for example for producing plates from plastics (with or without fillers), from concrete and the like.

Claims (17)

Process for the production of precisely dimensionally stable plate-shaped elements (50) from a setting material that can be cast during processing, in particular gypsum, in which the material is poured in the form of a slurry into at least one molding chamber (11) and then closed tightly and the slurry in the Allow the molding chamber to set at least until the elements formed from it are dimensionally stable, whereupon the elements are ejected from the molding chamber which is then open on one side and fed to a further treatment, characterized in that the molding chamber (11) is provided with at least one movable, in the manner of a Partition-acting core (14) is divided into partial mold chamber (15) and that the elements (50) formed in the partial mold chambers are ejected after setting together with their respective adjacent core (14) from the mold chamber and then separated from the core before they are sent for further processing. A method according to claim 1, characterized in that when the mold chamber is filled, each core is in a retracted filling position which at least partially leaves the mold chamber open, and in that, after pouring a corresponding amount of casting slurry into the mold chamber, the core is advanced into an operating position dividing the mold chambers (15), in which it is held until the pouring slurry sets. A method according to claim 2, characterized in that in the filling position the core with the front adjacent closing means (16) of the molding chamber is kept substantially the same. A method according to claim 3, characterized in that approximately simultaneously with the advance of the core (14) into the operating position, the closing means (16) of the molding chamber (11) adjacent to it are moved back in the opposite direction into an end position in which they remain until the setting of the Casting porridge are held and from which they are then moved together with the core into the ejection position while ejecting the elements (50). Method according to one of the preceding claims, characterized in that a molding box (6) is used which contains a plurality of molding chambers (11), each of which contains at least one movable core (14) and is divided by stationary parallel partition walls (10), and in that the Cores of all mold chambers are moved together. A method according to claim 5, characterized in that after reaching the ejection position, each core is moved back against the closing means by a predetermined amount before the elements are separated from the core. Apparatus for carrying out the method according to one of the preceding claims, with an open-topped mold box which contains at least one molding chamber delimited by walls which are parallel in pairs and which is closed at the bottom by strip-shaped closing means which are displaceably mounted in the molding chamber and are connected to an ejection device which are movable between a lowered end position and a raised ejection position, characterized in that in the mold chamber (11) is arranged at least one plate-like or disc-shaped movable core (14) acting in the manner of a partition, which is aligned parallel to two side walls (9) of the mold chamber and through which the mold chamber can be subdivided into partial mold chambers (15) which are closed at the bottom by the closing means (16) arranged on both sides of the core, so that the core (14) is coupled to an actuating device (21, 22, 20), by means of which it moves between a retracted filling position, which at least partially leaves the mold chamber open, one of the partial mold chambers ( 15) departmental operating position and an advanced ejection position is movable back and forth, and that the adjusting device of the core is synchronized with the ejection device (31, 25) in such a way that the core together during the ejection movement of the bottom-side closing means (16) of the molding chamber (11) with these is movable into its ejection position. Device according to claim 7, characterized in that the closing means (16) can be lowered from the filling position into the end position by the ejection device (31, 25), while the core (14) can be lowered by the adjusting device (21, 22, 20) the operating position can be moved forward. Apparatus according to claim 8, characterized in that in the filling position the core (14) is substantially flush with the end means (16) of the molding chamber (11) which are adjacent on both sides. Device according to one of claims 7 to 9, characterized in that the closure means have base strips (16) arranged on both sides of the respective core and that all base strips (16) have a common ejection device (31, 25) are connected. Apparatus according to claim 10, characterized in that the base strips (16) are connected to a base plate (25) which is mounted on a machine frame (2, 3, 5, 30) and which is coupled to at least one lifting or ejection cylinder (31). Apparatus according to claim 10 or 11, characterized in that each core is guided in a sealed manner between the base strips (16) adjacent to it. Device according to one of claims 10 to 12, characterized in that the bottom strips (16) are each formed with a projecting molding (17) corresponding to the spring of an element (50). Device according to claim 7, characterized in that each core (14) consists of a dimensionally stable material with a highly polished hard surface, Device according to one of claims 7 to 14, characterized in that each core (14) is connected to an adjusting device (21, 22, 20) common to all cores, Device according to claims 11 and 15, characterized in that the cores (14) are connected to a crossmember (20) which is movably mounted with respect to the base plate (25) and which is coupled to at least one lifting cylinder (21) which is connected between the base plate ( 25) and the traverse (20) is arranged, Device according to one of claims 9 to 16, characterized in that when the core (14) is in the filling position, the core (14) on the end face with the terminating means (16) held at the same height at a distance (42) corresponding to the height of a standard plate from that in cross section the cross-sectional dimensions of the standard plate corresponding upper edge of the molding chamber (6).

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