EP0332737B1 - Apparatus for making concrete multilayered roof tiles - Google Patents

Abstract

In this apparatus for making concrete multilayered roof tiles by the extrusion process, having a coating unit which can be supplied with fresh concrete and is intended for applying a continuous coating of fresh concrete to a continuous string of displaceable, positively driven bottom-half moulds (14), and furthermore a compaction roller (25) and a smoothing tool (35), adjoining the compaction roller (25) in the production direction, for compacting and if need be profiling the base coating of fresh concrete passing through underneath on the bottom-half moulds, at least one further smoothing tool (45) for a further coating, in particular a top coating (18), to be applied to the base coating (17) is provided in the production direction behind the smoothing tool (35) for the base coating (17) and is separated from this smoothing tool (35) by a gap (40) running transversely to the production direction. The material for the further coating is supplied under pressure through the gap (40). <IMAGE>

Description

The invention relates to a device for producing multilayer concrete roof tiles in the extrusion process. Furthermore, the invention relates to the concrete roof tiles available with the new device, which have, for example, a coating with improved weather resistance, color fastness and / or service life on a base body made of conventional concrete. The new device is suitable for the production of slab-like concrete roof tiles as well as for the production of profiled concrete roof tiles.

In particular, the invention relates to a device for the production of concrete roof tiles in the extrusion process with a coating system that can be supplied with fresh concrete for applying a continuous fresh concrete layer to a continuous strand of displaceable, positively driven sub-molds, also with a compacting roller and a smoothing device adjoining it in the production direction for compacting and optionally Profiling of the base layer of fresh concrete underneath on the lower molds and with a cutting station for cutting the compacted fresh concrete layer into Dachstein shaped pieces of the same length.

A device of this type is known from DE-A-35 22 846. After the cutting station, the Dachstein moldings pass through a spraying device in which a plastic coating or a coating of colored cement slurry is applied, onto which a colored granulate can be sprinkled. The roof tile moldings are then hardened in hardening chambers under controlled temperature and humidity conditions and then separated from the lower molds in a formwork removal station. In this typical procedure for the production of coated concrete roof tiles using the extrusion process, the coating is applied to the preforms which have already been formed. As experience has shown have, however, such coatings are largely weathered after 10 to 20 years, which brings about an undesirable change in the appearance of the concrete roof surface.

From DE-C-29 54 486 a process for the production of flooring slabs from various types of ceramic masses by the nozzle extrusion process is known. In this case, a plurality of further nozzles for the strip-like application of material for a plurality of parallel layers of a cover layer anchored in the base layer in a dovetail shape are arranged within a first nozzle for the base material.

From DE-A-18 15 973 a device for the strand production of multilayer concrete moldings, in particular roof tiles, is known. The finished roof tiles consist of a basic concrete layer and at least one further concrete layer to form the visible surface. The exposed concrete can differ from the basic concrete with regard to the content of color pigments and other additives as well as the grain structure and the like. The known device includes a filling funnel which is divided by partitions into successively arranged chambers for the different types of concrete. A spiked roller and a form roller are assigned to each chamber. At the last form roller in the direction of production there is a compression mouthpiece that compresses all sub-layers together. In this case, a spiked roller and a form roller are provided for each concrete layer. The mechanical effort is great and the production of uniform partial layers leaves something to be desired.

A machine is described in US Pat. No. 2,956,949 which enables the coating of concrete roof tiles with a spatula-like paste. This device is supplied with molds which have separating webs on their end faces with the height of the material thickness of the concrete roof tiles. Short sections of a fresh concrete layer are produced, each of the sections already having the shape of a Has concrete roof tile. There is a stuffing wheel in the loading station and a compressor directly after it. A roller with the direction of rotation in the opposite direction of rotation is provided in order to smooth the surface of the fresh concrete layer. The paste is then applied to the surface without pressure, the coated molds being drawn through under a pile of pent-up paste. The paste is pressed onto the surface of the fresh concrete by means of a compressor and then drawn through under a trowel element which is fixed in the longitudinal direction and rubs on the surface.

US-A-2,752,656 describes a device for the production of surface-coated aprons. Without compaction tools, the fresh concrete is filled into molds that have separators on their faces. In addition, the fresh concrete layer is divided by bars in the longitudinal direction. The fresh concrete layer is compacted using ramming tools. The cover layer is then applied in a second loading station, a rotating impeller being provided at the exit of the loading station. The surface of the base layer is roughened both by rubbing the lower layer on the material of the cover layer and by the impeller.

From US-A-3,138,843 a coating device for a device for producing plate-shaped roof tiles is known. In a device pivotable about a horizontal axis arranged transversely to the production direction, coating material applied to the surface of the brick blanks without pressure is stowed and distributed on a trowel-like web. The height of this web is adjusted by means of movable weights close to the surface of the brick blanks. The thickness of the coating is thus determined by weight. Following the first coating device, a second device is provided, by means of which viscous coating material is applied in webs into the still moist first layer. The second coating device is pivotally articulated on a horizontal axis arranged transversely to the production direction.

In contrast, the object of the present invention is to provide a device for producing multi-layer concrete roof tiles, which is simple in structure, can easily be integrated into an existing system of the type described at the outset, and with which excellent adhesion between the sub-layers and precise adherence to the layer thickness for every single sub-layer is achieved.

Starting from a device of the type mentioned above, the solution of the above object is characterized in that for the production of multi-layer concrete roof tiles in the production direction behind the smoothing device for the base layer and separated from it by a narrow gap running transversely to the production direction, at least one further smoothing device for one on the Another layer to be applied to the base layer, in particular a cover layer, is provided such that the contact surface of the further smoothing device is offset upwards by the layer thickness of the additional layer relative to the contact surface of the smoothing device for the base layer, that the smoothers for the base layer and for the further layer are arranged above Fastening means and adjusting means are fixed and aligned independently of one another, and that material can be fed through the narrow gap for the further layer under high mechanical pressure and precise metering by means of a pump.

With each additional smoother, the device according to the invention enables a further layer to be compressed and profiled independently of the base layer. The layer thickness of each partial layer can be set differently by arranging the smoothers accordingly. The additional smoothers can also be easily integrated into an existing production plant for the production of concrete roof tiles using the extrusion process, as is known from DE-A-35 22 846. Concrete roof tiles can then also be produced on a system modified in this way, whose base layer consists of simple, uncoloured concrete of sufficient strength and which have a top layer of high-quality, colored concrete, which ensures weather resistance over the long period usually desired today. Since the straightener can be fixed and aligned independently of one another by means of fastening means and adjusting means, the distance required for the respective layer thickness and the inclination of each straightener to the top of the lower molds can be precisely adjusted in a simple manner.

It is preferably provided that the smoothers for the base layer and for the further layer are held by a bridge spanning the conveying path of the lower molds, that at least one channel is provided in the bridge, the outlet of which opens into the gap between the blades, and that Entrance of the channel to which the pump which conveys the material for the top layer is connected. The common fastening of the smoothers to a bridge spanning the lower molds and the channel provided therein for the supply of the cover layer material enables the smoothers to be held securely and a streamlined material supply.

A screw pump is well suited as a pump, which guarantees the forced conveyance of paste-like masses, such as fresh concrete, under high mechanical pressure and which also enables precise metering of the top layer material supplied.

If the lateral edge areas of the gap between the blades are sealed with a flexible plastic profile, in particular made of polyurethane, an articulated seal between the blades can be ensured, even if the inclinations are not set in parallel.

Another feature of the invention relates to the multilayer concrete roof tiles obtainable with the device according to the invention, the base layer of which is smoothed and whose further layer (s), in particular cover layer, has been compacted, smoothed and optionally profiled by an additional smoothing device. The base layer can consist of natural-colored concrete of medium quality and sufficient strength; and the top layer consists of a higher-quality concrete containing color pigments. Furthermore, the concrete of the top layer can contain particularly fine-grained aggregates and selected dispersants. Through targeted selection of the top layer composition and an adapted compression of the top layer material, top layers can be produced with special properties, in particular high tightness, durability and color fastness. Considerable cost savings can be achieved because the content of expensive additives, such as color pigments, dispersants and particularly fine-grained additives, is limited to the top layer, the volume of which is significantly less than that of the base layer. In practice, the thickness of the base layer can be 7 to 11 mm, in particular 9 mm, and the thickness of the cover layer can be 1 to 3 mm, in particular 2 mm.

Fig. 1

eine Seitenansicht der erfindungsgemäßen Vorrichtung zur Herstellung von mehrschichtigen Betondachsteinen nach dem Strangpreßverfahren mit der Anordnung der Glätter im Schnitt;

Fig. 2

in größerem Maßstab die Anordnung der Glätter der Vorrichtung nach Fig. 1; und

Fig. 3

in einer perspektivischen Darstellung die Anordnung der Glätter nach Fig. 2.

The invention is explained in more detail below with reference to a preferred embodiment with reference to the drawings. It shows:

Fig. 1

a side view of the device according to the invention for the production of multilayer concrete roof tiles by the extrusion process with the arrangement of the smoother in section;

Fig. 2

on a larger scale the arrangement of the smoothers of the device of FIG. 1; and

Fig. 3

2 shows the perspective view of the arrangement of the smoothers according to FIG. 2.

1 shows - as a section of an overall system for the production of multilayer or coated concrete roof tiles by the extrusion process - in particular the coating system 20, the smoothing arrangement 30 and a cutting and dressing station 50. A conveyor 10 has an endless drive chain 11 which runs around a drive sprocket 12 and a deflection sprocket 13. Above the drive chain 11, sub-molds 14 arranged one behind the other lie in an uninterrupted strand on guides and are pushed by not shown drivers, which are fastened to the drive chain, through the coating system 20, past the straightening arrangement 30 and further through the cutting and dressing station 50 . A feed conveyor 15 delivers empty sub-molds, and a discharge conveyor 16 transports the roof tile moldings located on the sub-molds 14 19 further.

A fresh concrete container 21 of the coating system 20 is loaded with fresh concrete 23 from a mixer (not shown). The lower molds 14 pass under the outlet 22 of the fresh concrete container 21, and a spiked roller 24 evenly coats the lower molds 14 with a fresh concrete base layer 17. A compacting roller 25 adapted to the profile of the concrete roof tiles to be produced compresses and profiles the applied fresh concrete base layer 17.

Subsequently, the underforms 14 covered with the endless fresh concrete base layer 17 come under the smoothing arrangement 30. The smoothing arrangement includes - as can be seen in particular from FIGS. 2 and 3 - a bridge 31 spanning the underform strand, on which a smoothing device 35 for the base layer 17 and a smoother 45 is arranged for the cover layer 18. The smoother 35 for the base layer is inclined at a certain angle of attack with respect to the plane of travel of the lower molds 14 and, with its end face, which is formed to a pointed edge and faces the compressor roller 25, connects directly tangentially to its underside. With its contact surface 36, the smoother 35 presses, smoothes and profiles the fresh concrete base layer 17 located on the subforms 14 being transported past.

The straightener 45 for the cover layer is separated from the straightener 35 for the base layer by a narrow gap 40 running transversely to the production direction according to arrow A. The smoother 45 for the cover layer is also inclined at a certain angle of attack with respect to the plane of travel of the lower molds 14. The contact surface 46 of the smoothing device 45 is arranged higher by the layer thickness b of the covering layer 18 than the pressing surface 36 of the smoothing device 35. As is only indicated schematically, the material 44 for the covering layer 18, also a concrete-like mass, is used by a storage container 43 a pump 42, preferably designed as a screw pump, and by a pump in the bridge 31 provided channel 32 fed into the gap 40. A laminate of ready-compacted and profiled fresh concrete, consisting of the base layer 17 and the cover layer 18, leaves the shaping gap formed between the rear edge 46a of the smoothing device 45 for the cover layer and the top of the lower molds 14.

The laminate, which is still in the form of an endless strand, is then conveyed further on the lower molds 14 to a cutting and dressing station 50 (cf. FIG. 1), where the endless strand is cut into individual roof tile moldings 19 by the cutting knife 51. By means of a dressing tool 52, the foot-side edge of the roof tile moldings can then be trimmed, as is specified in DE-PS 22 52 047 or DE-OS 35 22 846. The Dachsteinformlinge 19 then go into hardening chambers, not shown, in which they harden under controlled temperature and humidity conditions. The concrete roof tiles are then separated from the lower molds 14 in a formwork removal station and then removed, while the lower molds are returned to production.

Further details of the arrangement of the smoothers 35 and 45 can be found in FIG. 3. The smoothers are attached to the bridge 31 spanning the machine bed and the conveying path of the lower molds 14. The straightener 35 for the base layer 17 is connected to the bridge 31 via fastening means 37, for which two screws are provided. The distance and the inclination of the smoothing device 35 with respect to the upper side of the lower molds 14 can be adjusted via adjusting means 38, for which four screws are provided. Corresponding fastening means 47 and adjusting means 48 are used for fastening and aligning the smoothing device 45 for the cover layer 18. The smoothing devices are arranged in such a way that between the smoothing device 35 and the smoothing device 45 there remains a narrow gap 40 running transversely to the production direction and the smoothing device 45 is independent of this Smoother 35 can be aligned. The pressure surfaces 36 and 46 of the smoother can be formed of a hard metal pad, which is connected via an intermediate layer of a metal / plastic mixture to a base made of steel, as is described in detail in EP-PS 0 035 010. The base can also be attached to the bridge 31 via an additional pressure plate.

The gap 40 is sealed in its lateral edge areas with an elastic plastic profile 41, in particular made of polyurethane, in order to prevent an undesired escape of material 44 for the cover layer 18 here. This material is conveyed under the pressure of the pump 42 through the channel 32, the outlet 34 of which opens into the gap 40 and the inlet 33 is connected to the pump 42. Under the high mechanical pressure of the pump 42, the material for the cover layer is evenly distributed in the gap 40, so that a smooth cover layer 18 is also produced on the fresh concrete base layer 17 with the aid of the smoothing device 45. In the illustrated embodiment, the length of the gap 40 extends over the entire width of the lower molds 14, so that a full-surface coating of the top of the roof tile is obtained, which also includes the fold area.

3, the lower molds 14 and the smoothers 35, 45 have a shape for producing profiled concrete roof tiles.

Claims (8)

1. Apparatus for making concrete multilayered roof tiles by means of extrusion process with a coating installation (20) suppliable with unset concrete (23) in order to apply a continuous layer of unset concrete (17) on a contiuous ribbon of forcibly actuated movable pallets (14), and further with a compacting roller (25) and a slipper (35) following it in processing direction in order to compact and, as the case may be, to profile the base layer (17) of unset concrete passing through underneath on the pallets (14) and with a cutting station in order to cut the compacted layer of unset concrete into roofing tile-mouldings of equal length,
   characterized in that
   for making multilayered roof tiles, in the processing direction after the slipper (35) for the basis layer (17) and separated from this slipper by means of a narrow gap (40) extending transversely to the processing direction, a further slipper (45) is provided for a further layer to be applied onto the basis layer (17), especially for a surface layer (18) in that the clamping surface (46) of the further slipper (45) is arranged upwardly shifted by the layer thickness (b) of the further layer in face of the clamping surface (36) of the slipper (35) for the basis layer (17), in that the slippers (35, 45) for the basis layer (17) and for the further layer are oriented and fixed independently of each other via fixing (37 and 47 respectively) and adjusting means (38 and 48 respectively), and that material (44) can be supplied through the narrow gap (40) for the further layer under high mechanical pression and precise dosing by means of a pump (42).
2. Apparatus according to claim 1,
   characterized in that
   the slippers (35, 45) for the basis layer (17) and for the further layer are hold by a bridge (31) traversing the conveying path of the pallets, in that, in the bridge (31), at least one conduit (32) is provided whose exit end (34) leads into the gap (40) situated between the slippers (35, 45) and that the entrance (33) of the conduit (32) is connected to the pump (42) providing the material (44) for the further layer.
3. Apparatus according to claim 2,
   characterized in that
   the pump (42) is a spiral pump.
4. Apparatus according to one of claims 1 to 3,
   characterized in that
   the lateral edge areas of the gap (40) between the slippers (35, 45) are sealed with a flexible plastic profile (41), especially in polyurethane.
5. A multilayered concrete roof tile, available with the apparatus according to one of the claims 1 to 4 whose basis layer (17) has been compacted, smoothed and, as the case may be, pofiled by a slipper (35) and whose further layer(s), especially a surface layer (18), has been compacted, smoothed and, as the case may be, profiled by an additional slipper (45).
6. A multilayered concrete roof tile according to claim 5,
   characterized in that
   the basis layer (17) consists in a natural-coloured concrete of medium quality and of sufficient consistency, and that the surface layer (18) consists in a concrete of higher quality containing colouring pigments.
7. Multilayered concrete roof tile according to claim 5 or 6,
   characterized in that
   the concrete of the surface layer (18) contains especially fine grained aggregates and selected dispersion mediums.
8. Multilayered concrete roof tile according to one of claims 5 to 7,
   characterized in that
   the thickness of the basis layer (17) amounts to 7 to 11 mm, especially to 9 mm, and that the thickness of the surface layer (18) amounts to 1 to 3 mm, especially to 2 mm.

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