EP0566084B1 - Process and device for making composite panels with natural stone slab - Google Patents

Abstract

A description is given of a process for producing composite stone slabs which each comprise a carrier layer of concrete and a natural-stone slab (4), the two of which are intimately connected to each other. The proposed mechanical process consists in that the natural-stone slab (4), which has been turned such that its upper side faces downwards, is moved onto a vibrating table and enclosed in a sealing manner by a mould frame (1), in that concrete is then introduced into the mould frame (1) and compacted by vibration, and in that the concrete layer applied in this manner is moulded by raising the mould frame (1). On its inner side, the mould frame (1) has a region (11) which corresponds approximately to the height of the natural-stone slab (4) and is set back. In this region there is arranged a peripheral groove (13) into which there is introduced a flexible hose (7), the internal pressure of which can be controlled. A description is also given of the moulding machine used and the feed and centring of natural-stone slabs (4). <IMAGE>

Description

The invention relates generally to a method and an apparatus for producing stone composite panels. The invention relates in particular to a process for the production of composite stone slabs each consisting of a lower base layer made of concrete in the use position and an upper natural stone slab which are intimately connected, in which the natural stone slab which is turned upside down is placed on a support surface and with a Form frame is sealed, and then placed in the mold frame concrete and this is compressed by means of a stamp and by shaking and finally the stone composite panel is separated from the mold frame.

Such stone composite panels are required, for example, where a natural stone floor covering is exposed to particularly high weight loads due to vehicles or for other reasons. The concrete base layer gives the natural stone the required breaking strength and its material value is much cheaper than natural stone. As far as composite stones of this type have been used so far, they were made entirely by hand. As a result, the saving effect of using the less expensive material concrete was practically negligible. In many cases, the connection between concrete and natural stone was also poor, which should not infrequently be due to inadequate compaction of the concrete.

NL-A-9 002 896 discloses a method and a device for producing composite panels, each consisting of a lower one in the position of use Base layer made of concrete and an upper cladding plate made of a ceramic material, which are intimately connected. In this known method, the facing panel facing downwards is introduced from above into a mold frame and placed on a support surface so that it is sealed by the mold frame. Fresh concrete is then introduced into the mold frame from above and compacted by means of a stamp and by shaking. Finally, the finished composite panel is removed from the mold frame.

FR-A-1 143 554 discloses a method and an apparatus for covering a prefabricated cuboid element. For this purpose, the prefabricated element is inserted from below into a fixed, rectangular centering frame with a lifting table. The centering frame is provided with a circumferential groove in which an inflatable tube is inserted. After the top of the element is aligned with the top of the groove, the tube is inflated to center the element with respect to the centering frame. This should also ensure that the element is centered with respect to a panel inserted in the centering frame. Then a press plate connected to a vibrator is lowered and brought into contact with the top of the panel. Due to the pressure applied in connection with the vibrations, the cladding is connected to the prefabricated element. The hose is then vented and the element, together with the panel attached to it, is pulled out of the centering frame by lowering the lifting table.

The invention has for its object to provide a usable mechanical method for producing stone composite panels, natural stone panels with a thickness of 3 to 5 cm and an area of e.g. 0.5 m² should be assumed. The concrete base layer can be 10 to 15 cm thick.

This object is achieved according to the invention by the method features characterized in claim 1.

In the method according to the invention, the mold frame serves as a transporter to deliver the natural stone slab from the support surface and to the vibrating table, and to lift the finished dressing slab from the vibrating table and place it on the support surface after the concrete has been applied and compacted.

A device suitable for carrying out the method according to the invention is specified in claim 12.

If the molding frame initially slides over the natural stone slab to enclose and hold it, it is important to avoid damage to the natural stone slab. Even a slight lateral offset or a twisting of the plate relative to the frame can lead to a hard impact and breakage of the natural stone plate if the mold frame moves down very quickly. It is therefore proposed that the natural stone slab be precisely and locally aligned with the projection of the mold frame by means of a centering device by moving it on its base before it is received in the mold frame. To do this, the centering device must first be brought to the natural stone slab. Movable straightening members of the device then move at least two intersecting edges of the natural stone slab against corresponding stop bars. Then the directors release the plate again and finally the whole centering device is moved back into a rest position.

Another type of alignment or centering of the natural stone slab on its base can advantageously already take place when it is placed on it, if this is done with the aid of a gripper, in particular a suction head. It is proposed to arrange a funnel-shaped guide shaft, the lower mouth of which corresponds almost exactly to the plate outline and is only slightly higher than the natural stone plate above the support surface. The natural stone slab is then lowered on the gripper, which can move freely in the horizontal direction, down through the shaft and aligns itself automatically.

The alignment problem can finally also be solved by the fact that the mold frame can be automatically adjusted to different plate formats, for example with the aid of hydraulic cylinders or the like. Such a form frame is first set to plate oversize and lowered so far that it surrounds the natural stone plate. This enables a desired, relatively large alignment tolerance when depositing the plates. However, if the natural stone slab is caught by the frame, the frame is tightened until its frame parts line up with the side surfaces of the natural stone slab and this is aligned.

A simple way of practicing the proposed method is to include a molding machine that can be moved on a track to use a vibrating table that can be moved horizontally back and forth in the machine. This type of machine is also used as a multi-layer paver, for example for concrete paving stones. The input of the natural stone slabs and output of the composite slabs can be done by hand. It is proposed that the natural stone slabs in the mold frame corresponding arrangements are designed with equal distances in the track of the mold frame on the floor, that the molding machine moves forward in accordance with these distances and that during each stop on the one hand the natural stone slabs of an arrangement by means of the mold frame are included with provided the concrete layers and placed on the floor as finished composite panels and that, on the other hand, the natural stone panels of a following arrangement are aligned by means of a centering device on the relevant projection of the mold frame.

However, the so-called floor production with a mobile mechanical device described requires long downtimes due to the hardening time required for the concrete to harden. In addition, a lot of space is lost due to the necessary large distances between the plates placed in the production hall. Since the production of the composite panels only takes place in batches, this manufacturing principle is relatively unproductive. Therefore, two further process variants are proposed below, each with stationary mechanical devices.

The following variant represents, as it were, the kinematic reversal of the floor production. Essentially the same molding machine can be used, also with a vibrating table that can be moved horizontally back and forth. However, this machine is arranged in a stationary manner, namely at a certain height on a pedestal and a horizontal conveyor runs under the machine. This is moving also gradually at equal intervals and supports the individually designed natural stone slabs. The form frame lifts the natural stone slabs away from the conveyor level on the vibrating table and after the concrete layer has been applied, the composite slab is put back on the conveyor and shaped in the process. The composite panels must then be removed from the horizontal conveyor for further processing and setting, for which purpose a gripper can preferably be used, which clamps the natural stone panel in question on two opposite side surfaces and can thereby carry it.

Another advantageous development of the method variants mentioned is that the stacked natural stone slabs are automatically separated by means of a horizontally and vertically movable suction head and laid out on the horizontal conveyor or the production boards.

Finally, it is proposed that in order to improve the connection of the concrete with the natural stone slab, a concrete strengthener, adhesive or adhesive is applied to the natural stone surface. It is particularly expedient to automatically wash the individually designed natural stone slabs before coating them with concrete on their underside facing upwards and then also to coat them automatically with the relevant adhesive, in particular a concrete adhesive.

Fig. 1

einen vertikalen Teilschnitt eines Formrahmens zur Herstellung von Verbundsteinen,

Fig. 2a

das Detail A aus Fig. 1 in größerem Maßstab,

Fig. 2b

in gleicher Darstellung eine andere Variante des Details A aus Fig. 1,

Fig. 3

eine mehrfach geschnittene Draufsicht einer Schlauchdichtung, wie sie bei dem Formrahmen nach Fig. 1 verwendet ist in einem bezüglich Fig. 2 etwas kleineren Maßstab,

Fig. 4 - Fig. 7

verschiedene Varianten von Schlauchquerschnitten im Maßstab wie Fig. 2,

Fig. 8

eine Seitenansicht einer fahrbaren Formmaschine mit ihrem Gleis, vorbereitend ausgelegte Natursteinplatten und fertige Verbundplatten,

Fig. 9

eine Draufsicht der Gesamtanordnung nach Fig. 8,

Fig. 10

ein Querschnitt der Zentriervorrichtung der Formmaschine nach Fig. 8 in größerem Maßstab und

Fig. 11

die Draufsicht der Zentriervorrichtung nach Fig. 10,

Fig. 12

eine Seitenansicht einer stationären Formmaschine mit zugehörigen stationären Komponenten, wobei als Förderer ein Endlos-Kettenförderer ohne mitlaufende Fertigungsbretter vorgesehen ist,

Fig. 13

eine schematische Draufsicht auf eine weitere Anlage zur automatisierten Herstellung von Mehrschichtplatten,

Fig. 14

eine schematische Seitenansicht eines Ablegewagens der Anlage nach Fig. 13,

Fig. 15

eine schematische Seitenansicht eines Fertigungswagens der Anlage nach Fig. 13, wobei zur besseren Veranschaulichung ein Teil der Seitenwand weggebrochen ist, und

Fig. 16

einen vertikalen Schnitt durch eine gefüllte Kastenform.

Some embodiments of the invention are explained below with reference to the drawing. In detail shows

Fig. 1

a vertical partial section of a mold frame for the production of composite blocks,

Fig. 2a

detail A from FIG. 1 on a larger scale,

Fig. 2b

in the same representation another variant of detail A from FIG. 1,

Fig. 3

2 shows a multi-sectional top view of a hose seal, as used in the form frame according to FIG. 1, on a somewhat smaller scale with respect to FIG. 2,

Fig. 4-7

different variants of hose cross sections on a scale like FIG. 2,

Fig. 8

a side view of a mobile molding machine with its track, prepared natural stone slabs and finished composite panels,

Fig. 9

8 shows a top view of the overall arrangement according to FIG. 8,

Fig. 10

a cross section of the centering device of the molding machine according to FIG. 8 on a larger scale and

Fig. 11

10 the top view of the centering device according to FIG. 10,

Fig. 12

1 shows a side view of a stationary molding machine with associated stationary components, an endless chain conveyor without a moving production board being provided as the conveyor,

Fig. 13

1 shows a schematic top view of a further system for the automated production of multilayer boards,

Fig. 14

FIG. 2 shows a schematic side view of a depositing carriage of the system according to FIG. 13,

Fig. 15

13 shows a schematic side view of a production trolley of the system according to FIG. 13, with part of the side wall broken away for better illustration, and

Fig. 16

a vertical section through a filled box shape.

Since two natural stone slabs are treated together in the manufacturing process to be described, the mold frame shown in FIG. 1 has two chambers. It consists of four outer walls 1, a support flange 2 being attached to each of two opposite walls. The chambers are separated from each other by a somewhat thicker partition 3 and each take on a square natural stone slab 4, which are 60 cm wide and 4 cm thick. Fig. 1 shows the situation at the end of the compression phase. On the natural stone slab, the visible side of which is turned downwards, there is an approximately 12 cm thick base layer 5 made of concrete. The stamping plates 6 fitting into the molding chambers, the load of which is not shown, can, as is customary in concrete molding machines, be moved in height independently of the molding frame.

Each natural stone slab 4 is enclosed by a sealing tube 7. In this example, it is a simple, cross-sectionally round tube according to FIG. 4, FIG. 2a showing this tube under high internal pressure, which deforms it accordingly. 3, the hose is composed of four miter cut and vulcanized sections. A connecting hose 8 branches off from the hose ring and is guided on one side facing away from the natural stone plate 4 through one of the outer walls 1 (not shown).

In its upper section, in which the stamp 6 runs and concrete is filled and compacted, the molding chambers have a clear width which corresponds exactly to the width of the natural stone slab 4. Starting a little above the natural stone slab, the molding chamber widens over an inclined shoulder 9 and forms an approximately 2.5 mm wide gap 10 with the side surfaces of the natural stone slab 4. The recessed flat surface section 11 at the lower end of the outer wall 1 goes into an inclined surface 12 below which, in the event of an inaccurate centering of the natural stone slab, is to prevent its damage when the mold frame is lowered.

In the area of the recessed surface section 11, the outer wall 1 has an essentially rectangular groove 13, the upper side wall of which is approximately at the same height as the upper surface of the natural stone slab according to FIG. 2. The groove is for opening, i.e. H. narrowed towards the natural stone slab by two bead-like arched projections 14 on the groove side walls. Finally, the natural stone slab 4 has a chamfer 15 on its upper edges.

The natural stone slab 4 is thus on all sides a distance from the outer wall 1, so that it can not be damaged when shaken. The all around uniform width of the gap 10 is also important because the side surfaces of the base layer 5 must form a common plane with the side surfaces of the natural stone slab 4. This also causes the hose 7 which can be acted upon by air pressure. It seals the gap 10 all around and presses so hard on the side surfaces of the natural stone slab 4 that it does not slip down when the mold frame is lifted, not even when concrete is already in the Mold chamber is filled and compressed. However, some of the concrete weight is carried by friction on the outer walls of the mold. Ultimately, the rubber hose at Form that the concrete slurry, which has entered the niche between the shoulder 9 and the hose 7 when shaken, is pushed up and distributed so that the finished composite panel with smooth side walls. For this purpose, the air pressure in the hose 7 is reduced to such an extent that the hose can fulfill the function of a wiping lip. The complete removal of the air pressure has the consequence that the hose 7 due to the beads 14 completely returns to the groove 13.

2b shows another embodiment of the sealing point on the outer frame wall 1a. The tube groove 13a has a slightly different cross-sectional shape than in the first exemplary embodiment. It is rounded at the bottom of the groove. Another rectangular groove parallel to it is provided above the hose groove, into which a shock protection strip 45 made of rubber or a suitable plastic is inserted. This groove lies at the transition point between the upper section and the lower, recessed section of the inner wall surface. The impact protection strip 45 is set back somewhat further than the upper section and protrudes beyond the lower section. The natural stone slab 4a used here has no bevel on the transition edge between its surface 46 and its side surface. The upper edge of the impact protection strip 45 lies above this surface 46 and the lower edge lies below this surface 46 of the natural stone slab.

5 shows another hose cross section which is intended for a groove with flat side walls and which accordingly has flat flanks 16 and a flat pressure surface 17. Wedge-shaped sealing lips 18 are formed on this in the manner of an adhesive suction cup.

6 differs from the previous one by a smaller oval cavity and by an almost rectangular solid profile section, the can also be referred to as a molded gripping and sealing strip 19.

In addition to a further hose profile, the associated groove shape is also shown in FIG. 7. What is essential here is a T-shaped profile projection 20 on the back, which engages in a corresponding shape of the groove base and thus holds the otherwise round tube in the groove, which widens towards the groove opening. If the hose is pressurized, it fills the groove and extends beyond it over a relatively large width, which is indicated by dash-dotted lines.

A molding machine 21 is shown schematically in FIGS. 8 and 9, which can move on rails 23 with its wheels 22. The floor surface between the rails is a flat surface, for example a smooth concrete line, and maintains a constant distance from the rail surface. The machine has columnar vertical guides 24, on which a stamp bear 25 and the mold frame 26 shown in FIG. 1 can be moved up and down independently of one another. The mold frame is filled from a storage silo 27 for the concrete mixture used by means of a horizontally movable filling box 28. Horizontal guides 29 make it possible to move a vibrating table from a working position in the area of the vertical guides to the right into a rest position, so that the mold frame 26 and the stamp bear 25 can be moved all the way down, so that the mold frame stands on the floor.

As shown in FIG. 8, in front of the molding machine 21 moving to the right, two natural stone slabs 4 are laid out next to one another at equal distances x between the rails 23. At an equal distance x index cams 30 are attached to a rail, which form-fit on the machine frame with a suitable gripping device fit together and thereby firmly connect the machine moving progressively from one index cam to the other at every stop with the running rail, so that the step size can be maintained with the highest precision.

The natural stone slabs 4 are deposited by hand and with only imprecise visual aids. A plastic film can be underlaid to protect the ground plate surface. So that the form frame can grasp the plate pairs precisely, they have to be aligned by machine, for which purpose a centering device 31 is provided in the example. It is articulated on the front of the molding machine so as to be pivotable upwards about a horizontal axis 32. It bears against a stop 33 in the swung-up rest position.

Details of the centering device are shown in FIGS. 10 and 11. A rectangular frame 34 made of U-shaped rails, on which two bearing arms 35 are seated, is approximately the size of two natural stone slabs 4. The frame cross leg facing away from the molding machine 21 carries a stop bar 36 which is at the bottom while on two cross struts is attached to the first vertical stop bar 37 pointing in the direction of travel. On the outside of the other frame legs, bearing eyes 38 are arranged in pairs, which carry swivel frames 39. With their buffers 40 and their pneumatic drive cylinders 41, these swivel frames form the aforementioned straightening members. 10 shows such a straightening member on the left side in the swung-out position.

The manufacturing process in connection with the described device proceeds as follows: The molding machine shown is located at one of the preselectable stops in contact with one of the index cams 30. In this position, two natural stone slabs 4 are located exactly below the molding frame 26. The next two pairs of slabs following are also below the Molding machine and are already centered. The next following pair of plates, however, is outside the base of the machine but in the area of influence of the centering device 31.

The form frame moves down and encloses the two natural stone slabs. The two hoses 7 are now pressurized and then the mold frame with the plates moves up. Now the vibrating table is moved to the left and the mold frame lowers on it. The air pressure is briefly reduced so that the natural stone slabs fit the vibrating table level. Now the air pressure in the hoses is increased again, so that the mold frame is sealed and the plates are held in the middle of their mold chambers. Now the mold frame is filled with a concrete mixture by driving over it with the filling box 28 and thereby vibrated in between. Then the stamps are lowered and the final compaction is carried out by means of the vibrating table and the vibrators of the stamp load. Then the mold frame lifts up a little together with the natural stone slabs, the compacted concrete filling and the stamps, so that the vibrating table can move to the side. Now the aforementioned arrangement moves downwards until the mold frame 26 stands on the floor. This is followed by shaping, for which the air pressure in the tubes 7 is reduced a little and only the mold frame 26 is first raised. The semi-limp hoses smooth the side walls of the concrete base course. Finally, the stamp bear 25 is also taken into the upper rest position.

Centering occurs during or after this molding process, but while the machine frame is still stationary. For this purpose, the centering device 31 is folded down so that two natural stone slabs are located under the rectangular frame 34 and roughly in the areas between the stop bars 36 and 37 and the directional members 39, 40. Now the pneumatic drive cylinder 41 actuates the latter, with the result that the buffers 40 move the natural stone slabs and bring them against the stop bars 36 and 37. The plates are now precisely aligned. The straightening organs are withdrawn and the entire centering device is pivoted up into its rest position. Since the pivot axis 32 is higher than the plates, the stop bar 36 immediately moves away from the plates, while the buffers no longer touch the plates when the device is pivoted up.

Now the molding machine advances another step x. The mold frame 26 can now accommodate another centered pair of plates. The finished composite panels 42 remain on the floor behind the molding machine 21. In the example, the longitudinal distance of the mold frame from the centering frame is three times the increment x, so that a certain centered pair of plates is picked up by the mold frame after three forward steps.

The system shown in FIG. 12 contains the same multi-layer paver machine as the molding machine 21a, as is also shown in the example according to FIGS. 8 and 9. The molding machine 21a is, however, stationary on approximately 60 cm high column feet 50 and is also arranged upside down. A horizontal conveyor, consisting of an endless chain 51 guided over two deflection rollers, not shown, moves under this molding machine. The chain is connected at intervals x supporting plates 52 made of steel in such a way that they can be deflected with the chain at the ends, in the conveying plane however, are guided exactly horizontally, with the aid of support rollers or the like ensuring that the support plates 52 can also be loaded with a sufficiently high weight. The conveyor moves gradually with the interposition of stopping times so that the support plates 52 are always in the same place below the centering device 31, come to a standstill below the mold frame 26, etc. The direction of conveyance runs from left to right according to the arrows indicated.

A molding and coating station 53 is connected upstream of the molding machine 21. It comprises a portal frame 54 bridging the conveyor, on the carrier rail extending in the conveying direction a trolley 55 can move. The trolley carries a vertically telescopic suction head 56 and a coating roller 57, which is also attached to a vertically telescopic handle. A stack 58 of delivered natural stone slabs is on a storage table 59. To the right of the centering device 31 is a trough 60 containing concrete adhesive.

A gripper station 61 is also indicated on the outlet side to the right of the molding machine 21a, which serves to laterally remove the finished composite panels from the conveyor and to feed them for further processing and determination. The gripper used here is designed so that it grips the respective natural stone slab of the composite slab on two opposite side surfaces.

The working procedure for this system is as follows: During a downtime, the suction head 56 detects the uppermost natural stone slab of the stack 58. The trolley 55 then moves so far to the right that the suction head can place the detected natural stone slab on the corresponding support plate 52 of the conveyor. During this time, the coating roller 57 picks up concrete glue from the trough 60. Then the trolley 55 again moves a little to the left and the coating roller 57 moves down and carries out the coating process. In the next station, the natural stone slab 4 prepared in this way is aligned by means of the centering device 31. In the next station, the natural stone slab comes to rest under the mold frame 26.

The machine carries out its work cycle as described in the previous exemplary embodiment, ie the molding frame picks up the natural stone slab and then places the finished composite slab on the same support plate 52 again. The composite plate is removed from the conveyor in the gripper station 61. Additional auxiliary stations can be switched on as required. So it is z. B. expedient to wash the surface of the natural stone slab before applying the concrete adhesive. Even after the composite panel has been completed, it may be necessary to automatically clean the side surfaces of the natural stone panel by scraping or washing residues of adhesive.

The system according to FIG. 12 can, as shown in the first exemplary embodiment according to FIGS. 8 and 9, be designed for the production of two plates lying next to one another or also for individual production.

The system for the automated production of multilayer boards shown in FIG. 13 comprises an elongated working platform 110 on which a rail track 112 is arranged. A laying carriage 114 and a production carriage 116 are movably mounted on this rail track 112.

The laying carriage 114 carries two stacks of natural stone plates 118 arranged side by side, which form the cladding plate of a multilayer plate. The natural stone slabs 118 are stacked with their processed front facing downward. The laying carriage 114 also carries a storage container 120 for a cement adhesive. An overhead rail 122, on which a trolley 124 is suspended, is supported on the laying carriage 114. The trolley 124 carries an application device 126, for example a rotating roller, which can be immersed in the storage container 120 for the cement adhesive. The trolley 124 also carries a storage device 128 formed by a suction head. The end positions of the trolley 124 are determined by limit switches (not shown).

At the front end of the laying carriage 114 in the direction of travel, an alignment frame 130 is pivotably articulated. This alignment frame 130 has a plurality of frame legs, which can be brought to bear on the side surfaces of two deposited square natural stone plates 118. Some of the frame legs of the alignment frame 130 are powered (not shown), e.g. Pneumatic cylinder, provided and horizontally movable. These movable frame legs can be brought to bear on two adjacent side surfaces of a deposited natural stone slab 118 in order to press them against the two rigid frame legs and thus align them.

The production trolley 116 is mounted on the rail track 112 behind the trolley 114 when viewed in the direction of travel. The production trolley 116 carries a storage container 132 for fresh concrete. In the manufacturing cart 116 are a box shape 134 and a ram 136 vertically movable in opposite relationship. In the production car 116, a loading device 138 and a vibrating table 140 are also arranged to be horizontally movable.

As can be seen from FIG. 16, a circumferential groove 142 is arranged on the inside of the box shape 134 in the lower region, into which one or more hoses 144 made of an elastic material are inserted. The hoses 144 can optionally be connected to a pressure medium source or to a vacuum pump, so that they protrude inward beyond the inner surface of the box shape or are drawn into the relevant groove 142.

A positioning device is provided to ensure the required relative position between the laying carriage 114 and the production carriage 116. For this purpose, positioning openings 146 are arranged in the work platform 110 at suitable intervals. Both the laying carriage 114 and the production carriage 116 are provided with vertically movable dowel pins 148 which can be brought into engagement with one of the positioning openings 146.

In the event that this positioning device is not sufficient to ensure that the box mold 134 is aligned vertically with a natural stone slab 118 placed on the work platform 110 from the laying carriage 114, an alignment frame, which is similar, can be arranged on the front side of the production carriage in the direction of movement is designed like the alignment frame 130 arranged on the laying carriage 114.

The system described above and shown in FIGS. 13 to 16 operates as follows:

First of all, the laying stone 114 places the natural stone slabs 118 in pairs on the work platform 110 at the intervals specified by the positioning openings 146. For this purpose, the suction head 128 lifts the uppermost natural stone plate 118 of the stack and the trolley 124 is moved to the right, whereupon the suction head 128 is lowered in order to place the natural stone plate in the alignment frame 130 on the work platform 110. The movable frame legs of the alignment frame 130 are then brought into contact with the associated power drives on two adjacent side surfaces of the natural stone plate 118 in order to press them onto the two rigid frame legs and to align them. The suction head 128 is then raised and the trolley 124 is moved further to the right, whereupon the applicator 126 is lowered in order to provide the sawn-rough back of the natural stone slab 118 with cement adhesive 150. The frame legs of the alignment frame 130 are somewhat higher than the natural stone plate 118, so that the cement adhesive does not run off to the side. Before the cement adhesive is applied, the back of the natural stone plate 118 can be moistened. After the application device 126 has been raised and the trolley 124 has been moved back into its starting position, the alignment frame 130 with the associated power drives is pivoted upward, so that it releases the natural stone plate 118. Thereupon, the laying carriage 114 on the rail track 112 is moved to the right to the next positioning openings 146.

Depending on the movement of the laying carriage 114, the production carriage 116 is also moved to the right and, by snapping the dowel pins 148 into the associated positioning openings 146, positioned so that the raised two box shapes 134 with two placed on the work platform 110 and one layer 150 out Align cement stone provided with natural stone slabs 118 vertically. The two box shapes 134 are then lowered until they rest on the work platform 110 and receive the associated natural stone slab 118. The elastic hoses 144 arranged in the grooves 142 of each box shape 134 are then connected to the associated compressed air source. As a result, the tubes 144 expand and protrude from the inside of the box mold 134 and are pressed against the side surface of the natural stone slab 118 and clamp the natural stone slab between them. The two box molds 134 are then lifted to an upper position together with the clamped natural stone plates 118, and the vibrating table 140 is moved to the left with the associated power drive in order to support the two natural stone plates 118 from below. The loading device 138 filled with fresh concrete from the storage container 132 is moved to the left with the associated drive on a base until it is aligned with the two box shapes 134, whereupon the fresh concrete is emptied into the two box shapes. It is important that the fresh concrete is applied to the cement adhesive that has not yet hardened.

After the loading device 138 has been moved back to its starting position to the right, the two press rams 136 are moved downward with the associated drive. While the plungers 136 press from above onto the fresh concrete introduced into the associated box shape 134, the vibrating table 140 is set in vibration so that the fresh concrete is compacted. As soon as the height of the fresh concrete has decreased to a certain level, the press rams 136 are raised and the vibrating table 140 is moved back into its starting position. In order to reduce the friction, the top of the vibrating table can be coated with a particularly lubricious plastic.

The total weight of the multi-layer plate consisting of the natural stone plate 118 and the carrier plate 152 formed from the fresh concrete, which is of the order of 120 kg, is now absorbed by the clamping effect or friction of the inflated hoses 144.

The two box molds 134 are then lowered until the natural stone plates 118 rest on the work platform 110. The hoses 144 are then connected to the vacuum pump so that they are completely in the associated Retract grooves 142. The two box shapes 134 can therefore be pulled up from the associated multilayer plate without the hoses 144 rubbing on the side surface thereof.

This completes a production cycle and the production carriage 116 can be moved to the right by a division predetermined by the spacing of the positioning openings 146, whereupon the processes described above are repeated.

In a departure from the exemplary embodiment shown, it is also possible to rigidly connect the production trolley 116 to the storage trolley 114.

With the system described above, square multilayer boards with an edge length of up to 60 cm can be produced. The natural stone slab 118 has a thickness of 4 cm, while the thickness of the concrete layer forming the support slab 152 is 12 cm.

After curing, the cement adhesive 150 forms an elastic adhesive bridge between the natural stone plate 118 and the carrier plate 152, which enables the concrete to shrink without cracking. The multilayer board is therefore characterized by great durability. The multi-layer board proved to be extremely resistant during roll-over tests, and there was no detachment in the area of the cement adhesive. Such a cement adhesive, which forms an elastic adhesive bridge in the hardened state, is sold by PCI Polychemie Augsburg GmbH.

The multilayer board can be handled after two days and easily installed with a vacuum gripper.

One skilled in the art can see that the drives assigned to the moving parts of the system described above operate with a corresponding program control be able to achieve an automatic workflow.

Reference symbol list:

1

Outer wall

1a

Outer wall

2nd

Supporting flange

3rd

partition wall

4th

Natural stone slab

4a

Natural stone slab

5

Base course

6

Stamp plate

7

tube

8th

Connecting hose

9

shoulder

10th

gap

11

Surface section

12th

Sloping surface

13

Groove

13a

Groove

14

head Start

15

chamfer

16

Flank

17th

Printing area

18th

Sealing lip

19th

Gripping and sealing strip

20th

Profile approach

21

Molding machine

21a

Molding machine

22

wheel

23

rail

24th

Vertical guidance

25th

Stamp bear

26

Molded frame

27

Storage silo

28

Filling box

29

Horizontal guides

30th

Index cams

31

Centering device

32

Swivel axis

33

attack

34

Rectangular frame

35

Bearing arm

36

Stop bar

37

Stop bar

38

Bearing eye

39

Swing frame

40

buffer

41

Drive cylinder

42

Composite panel

45

Bumper strips

50

Pillar base

51

Chain

52

Support plates

53

Application and coating station

54

Portal scaffold

55

Trolley

56

Suction head

57

Coating roller

58

stack

59

Filing table

60

trough

61

Gripper station

65

Molding machine

66

Vibrating table

67

Board conveyor

68

Pawl

69

Manufacturing board

70

Board magazine

71

Molded frame

72

Stamp bear

73

Vertical guidance

74

Filling truck

75

Lay-up station

76

Suction head

77

Coating station

78

Coating roller

79

Storage jar

x

Increment

110

Work platform

112

Rail track

114

Storage trolley

116

Production car

118

Natural stone slab

120

Storage container

122

Overhead rail

124

Trolley

126

Application device

128

Suction head

130

Alignment frame

132

Storage container for fresh concrete

134

Box shape

136

Ram

138

Loading device

140

Vibrating table

142

Groove

144

tube

146

Positioning openings

148

Dowel pins

150

Cement glue

152

Carrier plate

Claims (27)

1. Process for producing composite stone slabs comprising in each case a concrete load-bearing layer, which is at the bottom in the use position, and a top natural-stone slab, these being bonded intimately to one another, in the case of which process the natural-stone slab (4; 118), which is turned so that its upper side faces downwards, is laid on a supporting surface (52; 110) and is enclosed in a sealing manner by a moulding frame (26; 134), and concrete is then introduced into the moulding frame and is compacted by means of a ram (6; 136) and by vibration and, finally, the composite stone slab is separated from the moulding frame (26; 134), characterized in that the moulding frame (26; 134) is lowered from above onto the natural-stone slab (4; 118) until it encloses said slab, in that, out of the inner wall of the moulding frame (26; 134), gripping members (7; 19; 144) are pressed against the side surfaces of the natural-stone slab (4; 118), in that the natural-stone slab, together with the moulding frame (26; 134), is then raised and laid on a vibrating table (140), in that concrete is introduced into the moulding frame (26; 134), in that, after the concrete has been compacted, the finished composite slab (42; 118, 152) is raised, together with the moulding frame (26; 134), from the vibration table (140) and is set down on the supporting surface (52; 110), whereupon the gripping members (7; 19; 144) are drawn into the inner wall of the moulding frame (26; 134) and the moulding frame is then raised off from the finished composite slab, as a result of which the latter is demoulded.
2. Process according to Claim 1, characterized in that, before being received in the moulding frame (26), the natural-stone slab (4) is aligned, by means of a centring device, by being displaced on its base, in a precise manner, locally and angularly, with respect to the projection of the moulding frame.
3. Process according to Claim 2, characterized in that movable aligning members (39, 40) of the centring device (31) press the natural-stone slab (4), by at least two intersecting edges, against corresponding stop strips (36, 37) of the centring device, and in that the aligning members then release the natural-stone slab again.
4. Process according to Claim 1, characterized in that the natural-stone slab is deposited on its production base by means of a horizontally freely movable gripper and is aligned, by means of a fixed funnel-like guide shaft, with the position corresponding to the moulding frame.
5. Process according to Claim 1, characterized in that an adjustable moulding frame which is initially set to slab oversize is lowered to such an extent that it encloses the natural-stone slab, and in that the frame parts are then displaced with respect to one another to such an extent that they rest closely against the side surfaces of the natural-stone slab, with horizontal alignment of the natural-stone slab.
6. Process according to Claim 1, characterized in that use is made of a moulding machine (21) which can move on a track (23) and has a vibrating table which can be displaced back and forth horizontally in the machine, in that the natural-stone slabs (4) are laid out on the ground, in arrangements corresponding to the moulding frame (26), at regular intervals (x) in the track of the moulding machine (21), in that the moulding machine (21) advances in steps corresponding to said intervals (x), and in that, during each stop, on the one hand the natural-stone slabs of one arrangement are received by means of the moulding frame (26), provided with the concrete layers (5), and are set down on the ground again as finished composite slabs (42) and, on the other hand, the natural-stone slabs (4) of an arrangement which precedes in the direction of travel are aligned, by means of a centring device (31), with respect to the relevant projection of the moulding frame.
7. Process according to Claim 1, characterized in that use is made of a stationary moulding machine (21a) which has a vibrating table which can be displaced back and forth horizontally in the machine, and in that, by means of a horizontal conveyor (51) which advances in a stepwise manner at regular intervals (x) in a plane beneath the vibrating table, the natural-stone slabs (4) are fed to the moulding machine (21a) and the finished composite slabs (42) are guided away from the moulding machine.
8. Process according to Claim 7, characterized in that the newly finished composite slabs (42) are removed from the horizontal conveyor with the aid of a gripper (61), which clamps in the natural-stone slab of the finished product on two opposite side surfaces and can thus carry said slab.
9. Process according to one of the preceding claims, characterized in that the natural-stone slabs, delivered in stacks, are automatically separated and laid out by means of a horizontally and vertically displaceable suction head.
10. Process according to one of the preceding claims, characterized in that the natural-stone slabs (58), delivered in stacks, are automatically washed, before being coated with concrete, on their upwardly oriented underside and are then automatically coated with a concrete adhesive.
11. Process according to Claim 1, characterized in that, in order to improve the bonding of the concrete to the natural-stone slab, a concrete-consolidating agent, bonding agent or adhesive is applied onto the natural-stone surface.
12. Apparatus for carrying out the process according to Claim 1, characterized by an elongate supporting surface (52; 110) with virtually horizontal surface; by a depositing machine (53; 114) which is arranged such that it can be moved horizontally with respect to the supporting surface and which is loaded with stacked natural-stone slabs (4; 118), comprising a depositing device (128) for depositing, in a positionally accurate manner, a natural-stone slab, with its machined front side oriented downwards, on the supporting surface (52; 110), comprising an application device (126) for applying a cement adhesive (150) onto the upwardly oriented rough-sawn rear side of the deposited natural-stone slab, and comprising drive devices for moving the depositing machine (53; 114) with respect to the supporting surface (52; 110) and for actuating the depositing device (128) and the application device (126); by a production machine (21; 116) which can be moved horizontally with respect to the supporting surface (52; 110), comprising a vertically movable, open moulding frame (26; 134) whose inner dimensions are slightly greater than the outer dimensions of the natural-stone slab (4; 118) and which is provided on the inner sides with grooves (13; 142) into which there are inserted gripping members (7; 19; 144) which are connected to a drive device and can be pressed onto the border surfaces of the natural-stone slab, it being possible for the moulding frame (26; 134) to be lowered onto a natural-stone slab (4; 118) deposited on the supporting surface (52; 110), in order to enclose said slab on all sides, and then to be raised, with the natural-stone slab, to a specific level once the gripping members (7; 19; 144) have been activated, comprising a vibrating table (140) which is arranged such that it can be moved horizontally and which can be positioned beneath the raised moulding frame (26; 134) in order to support the natural-stone slab (4; 118), comprising a supply container (27; 132) for fresh concrete, comprising a charging device (28; 138) which is arranged such that it can be moved horizontally, which can be positioned beneath the supply container (27; 132) in order to receive a specific quantity of fresh concrete and then moved horizontally, and which can be positioned above the moulding frame (26; 134) supported by the vibrating table (140), in order to fill said frame with fresh concrete, comprising a pressing ram (25; 136) which is arranged such that it can be moved vertically above the moulding frame (25; 134) and whose outer dimensions are slightly smaller than the inner dimensions of the moulding frame and which can be lowered onto the fresh concrete located in the moulding frame in order to compact said concrete, in interaction with the vibrating table (140), to a specific level, and comprising drive devices for moving the production machine (21; 116) with respect to the supporting surface (52; 110), the moulding frame (26; 134), the vibrating table (140), the charging device (28; 138) and the pressing ram (25; 136); and by a positioning device (30; 146, 148) for the correct positioning of the depositing machine (53, 114) and of the production machine (21; 116) with respect to the supporting surface (52; 110).
13. Apparatus according to Claim 12, characterized in that positioning openings (146) are arranged along the supporting surface (110), and in that positioning pins (148), which can be brought into engagement with the positioning openings, are arranged on the depositing machine (114) and on the production machine (116).
14. Apparatus according to Claim 12 or 13, characterized in that arranged on the depositing machine (114) and/or on the production machine (116) is a vertically movable aligning frame (130) which exhibits two horizontally movable frame legs which can be brought to rest against two adjacent side surfaces of a deposited natural-stone slab (118).
15. Apparatus according to one of the preceding claims, characterized in that the depositing machine (114) and the production machine (116) are connected rigidly to one another.
16. Apparatus according to Claim 12, characterized in that an elastic hose (7), whose internal pressure can be controlled, is inserted into the groove (13) of the moulding frame (26).
17. Apparatus according to Claim 16, characterized in that the hose (7) forms a closed ring, the connection line (8) of which passes through the wall of the moulding frame.
18. Apparatus according to Claim 16, characterized in that the groove (13) is narrowed, towards the groove opening, by bead-like protrusions (14) of the groove side walls.
19. Apparatus according to Claim 16, characterized in that the hose exhibits planar flanks (16) which can be laid against planar groove-side-surface sections.
20. Apparatus according to Claim 19, characterized in that the hose exhibits a planar pressure surface (17) which extends between the flanks.
21. Apparatus according to Claim 16, characterized in that the hose exhibits a pressure surface provided with sealing lips (18) or channels.
22. Apparatus according to Claim 16, characterized in that a cross-sectionally rectangular gripping and sealing strip (19) is integrally formed on the hose.
23. Apparatus according to Claim 16, characterized in that the hose is secured on the rear side, with the result that it draws back into the groove due to its elasticity or being subjected to subatmospheric pressure (Figure 7).
24. Apparatus according to Claim 16, characterized in that, above the hose-containing groove (13a), an elastic impact-protection strip (45) is inserted into a further groove, parallel to the first groove, in the moulding-frame inner side.
25. Apparatus according to Claim 24, characterized in that the upper edge of the impact-protection strip (45) is arranged at a higher level, and the lower edge of the impact-protection strip (45) is arranged at a lower level, than the horizontal upper surface (46) of the natural-stone slab (4a).
26. Apparatus according to Claim 12, characterized in that, on its inner side, in the thickness region of the natural-stone slab, the moulding frame exhibits a peripheral groove, and in that provided in the groove sections of each wall of the moulding frame is a plastic strip which can be moved perpendicularly with respect to the wall.
27. Apparatus according to Claim 12, characterized in that the inner-surface sections (11), corresponding to the thickness of the natural-stone slab (4), of the moulding frame (26) are set back with respect to the rest of the inner surface.

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