EP1095197A1

EP1095197A1 - Rapid construction and formwork panel, method for trimming the same, and method and device for the production thereof

Info

Publication number: EP1095197A1
Application number: EP00943551A
Authority: EP
Inventors: Gunter Tannhäuser
Original assignee: Individual
Current assignee: Individual
Priority date: 1999-05-08
Filing date: 2000-05-05
Publication date: 2001-05-02
Also published as: AU5802100A; DE10081253D2; WO2000068527A1

Abstract

The invention relates to a trimmable rapid construction and formwork panel which is provided in a sandwich structure and which is comprised of a core material (4) that is resistant to crushing and shearing and is covered on both sides with an outer layer (2, 3) having tensile strength. One (2) of the outer layers can be cut through using a hand knife tool. The other outer layer (3) can be broken off. The core material is structured such that it breaks off cleanly, therefore, without the formation of dust or without fringing or splitting along the cutting line in the first outer layer (2). A particle board provided as core material (4) is produced by electrostatically aligning the wood particles such that they are perpendicular to the outer layers (2, 3). To this end, the device comprises corresponding electrodes.

Description

Quick build and formwork panel as well

Process for preparing such and process and device for its production.

Technical field

The invention relates to a ready-to-use quick-assembly and formwork panel in a sandwich structure, made of a core material that is resistant to compression and shear and is coated on both sides with a tensile outer layer, according to the preamble of claim 1. The invention further relates to a method for dressing such a quick-assembly and formwork panel and a method and a device for their production.

State of the art

Such a quick build and formwork panel has long been known from DE-PS 880 931.

Up to now, formwork for concrete construction has usually been made of plywood where there are no through-going areas, but outbreaks and more complicated shapes or small areas or areas that cannot be executed in the grid of prefabricated formwork.

The required cuts are made with a circular saw and, for complicated shapes, with a jigsaw. Working with a circular saw is, in addition to pneumatic hammers, the loudest and most annoying source of noise in construction, and one of the main sources of accidents. Cutting is time-consuming, requires qualified handling and the operation of a circular saw. The reuse of used formwork panels is often uneconomical, in addition to the accumulation of smaller and smaller pieces due to waste, also because they have to be cleaned and - if not coated with resin or foil - treated with formwork oil.

The cleaning not only serves to ensure perfect concrete surfaces, but is also necessary so that concrete residues do not blunt the saw blade of the circular saw. In addition, all scrap wire residues and nails must be removed, otherwise they will damage the circular saw blade and pose a significant risk of accidents.

In the case of temporary assemblies and installations, such as for trade fairs and exhibitions, panels often have to be prepared on site under time pressure. Working with the saw is time-consuming and labor-intensive, and the associated noise, dust and chip waste are bothersome.

The object of the invention is to at least partially remedy these disadvantages and to create a board which can be trimmed with simpler means or cleaner than was previously possible.

A variety of boards are already known, particularly in addition to the above-mentioned DE-PS 880 931, also DE 43 09 991 AI, DE 80 32 791 Ul, DE 92 09 406 Ul, DE 94 07 109 Ul, DE 42 08 812 AI and the DE brochure "Jackoboard building board" from Genifex, No. 3511/04. The disadvantages mentioned above occur with these panels.

Also known from DIN 18215 and DIN 68791 blockboards, in which the rods of the core material are parallel to the outer layers. Cutting is only possible with a saw.

Gypsum plasterboards, on the other hand, are easy to prepare, but are sensitive to moisture and breakage and therefore cannot be used as formwork panels. Otherwise, they cannot be prepared without dust and dirt. Known formwork panels made of sandwich composite material (IT UD950140 950714 or EP 0753394 A2 970115) can only be used as ready-made shells because of their difficult formability.

Furthermore, a large number of sandwich panels are known which are provided with semi-rigid plastic foams and outer layers which can be separated by the blade (for example "depafit" panels). These panels do not meet the static requirements for a quick-build or formwork panel.

Other known sandwich panels (EP 0753392 A2 970115, EP 0741638 AI 961113, EP 07563394 A2 970115, EP 0711652 AI 960515 and WO 9717195 AI 970515) are either firm enough, but then difficult to dress, or easy to dress, but then not firm enough.

From US 3,376,185 it is known to cut material lengthways and crossways by means of blade shares.

Sandwich panels with inner tube layers are known from EP 0741638 AI 961113.

DE-PS 976 840 and US Pat. Nos. 4,432,916, 4,347,202, 4,323,338, 4,322,380, 4,113,812, 4,111,294 and 3,843,756 are known for the electrostatic alignment of the chips in the production of a particle board .

The next-coming publication DE-PS 880 931 shows a building board with a filler layer made of a core material that o. Ried, straw or the like. is formed. According to the description, this building board is provided with a frame which prevents any cutting or the like, because it would then be cut and the reed filling would no longer hold together. It is not possible to prepare such a building board.

Presentation of the invention

A board of the type mentioned at the beginning will solve the above

Task further developed in that at least one of the

Outer layers can be severed with a blade hand tool in accordance with the desired dressing, the core material, for example following the cutting edge, can be broken off cleanly and at least the other outer layer can be broken off cleanly after kinking. The term "clean" means that the core material or the other outer layer does not roughly fray, does not crumble and does not break in a zigzag manner when broken off.

The invention also has the task of further improving and reducing the cost of this quick-assembly and formwork panel and of providing a method for cutting it out as inexpensively as possible, with high accuracy and with a greatly reduced risk of error, even if complicated shapes are required. Furthermore, a method for producing such a panel and an apparatus for carrying out the method are to be specified.

To solve the problem, the invention proposes to use a end grain board as the core material, in which the fiber course extends transversely to the outer layers.

Alternatively, however, a chipboard can also be used as the core material, in which the chips are oriented transversely and are held together by means of a glue, the lower supply of heat becoming liquid.

Ways of Carrying Out the Invention

The board according to the invention obtains its strength from the tensile strength of its outer layers and the crush resistance of its outer and core material. The dressing is done by cutting one of the outer layers, perhaps also the core material, with a knife and breaking the other outer layer by bending the panel apart at the point of separation. Thus, one of the outer layers must be tensile but easily cut through, while the other outer layer must be tensile but breakable. This requirement is met by very thinly cut veneers (so-called micro veneers) and press-tempered veneers, applied in several layers with an offset fiber direction, or pre-stretched polystyrene foils with hardener additives or hardening primer coatings.

Also suitable as outer layers are, for example, thin cardboard impregnated with phenolic resins and very thinly peeled, short-fiber Veneer (which does not form needles when broken), but also metal or plastic in the form of foils or thin plates, for example made of PMMA or two-sided expanded polystyrene with hardening admixtures. In addition, hard or hard impregnated or soaked with well-adhering and strongly hardening materials or thin felts, especially fiber plastics, come into question, as far as they can be cut with a simple knife. In particular, EP and UP resins are conceivable as impregnation materials.

For some applications, it is advantageous not to build the panels symmetrically, but to provide them with different surfaces, which are then used according to the load. The tensile outer layer is reinforced with fiber fabric and can be cut, the compressive outer layer is harder and more shear-resistant, but it is breakable and less tensile.

Basically, all crush-resistant materials can be used as core material, which connect to the outer layers and are difficult to shear off, but at the same time are either easy to cut through or can be broken with little dust. On the one hand, these are rigid foams and similar materials, especially those that can be produced with an increasing outward compression of the material, i.e. a skin, that shears off with difficulty and is increasingly resistant to compression on the outside, such as rigid PUR foams and surface-compressed rigid polystyrene foams. However, it is also possible to use adhesive materials that penetrate deeply into the foam, such as two-component polyurethane foam adhesive, instead of the surface compaction, or to apply the outer layers with heat and pressure when using thermoplastic foams, so that the edge zones of the foam core are compressed at the same time. Other core materials are cork, glass or metal foams and ceramic-like materials, bound natural fibers and residues (pressed wood fibers, peanut shells, cotton seeds), and other vegetable fibers with appropriate binding and preferably long, uniformly aligned fibers. Materials made of glazed, ceramicized and carbonized fibers are particularly preferred because of their favorable fire behavior in interior fittings. Core material made of needles, tubes and straws or of segmented solid materials, for example in the form of blocks, which are connected to one another by friction or are only slightly glued for easier processing, but are firmly connected to the outer layers, are particularly suitable for higher loads. Straws made from cereal or reed straw are particularly inexpensive, and advantageously segmented material is wood or pressed or extruded materials such as presswood, plastic renegates or hot-pressed plastic waste or other residues. Particularly light versions result in balsa wood, which is preferably segmented (criss-cross-slotted), with surfaces made up of Hinrholz discs, along with tubes made from a wide variety of materials, such as light metal or plastic, possibly in various basic geometric shapes, as well as combinations of these elements.

For a version for interior construction, in particular for thermal insulation and for achieving high fire protection, mineral fibers are suitable as core material, which are arranged perpendicular to the outer layers and only slightly with each other, but more strongly with each other and with the outer layers in the edge zones by foam adhesive or the like are connected.

Cooked wood fibers can be used in a similar form, such as those in soft fiber insulation boards, but also chip or OSB cores, in which the chips are sieved and poured in such a way that they are aligned perpendicular to the outer layers and with the outer layers of the core material and firmly connected to the outer layers, but are only pressed together in the interior of the core material.

In a simple design, the elements of the segmented core material consist of cube-shaped blocks or rods with a square cross section.

Advantageous because it can be cut to any size is core material made of fine pencils, for example a square cross-section, such as wooden pencils as used for matches. Here can be cut at any point and at any angle become; when breaking off, a slightly unclean edge is formed, because the breaking edge of one outer layer does not exactly follow the cutting course of the other, but rather the position of the rods still held or separated under the cutting edge on the outer layer. But the tolerance is at most ± one rod width and is therefore not greater than that of a cut with a circular or jigsaw.

The core material can also consist of veneers, preferably veneers made of peeled softwoods, which are pressed into thick packages with the same direction of grain and cut across the fiber into strip packages with the width that corresponds to the desired thickness of the core material of the later panels. Now an outer layer is applied and the semi-finished sheet is drawn over a roller, which exposes it to a defined tension on the open top. At the apex, the veneers in the desired width of the chopsticks are continuously split by a cleaver mechanism. After returning to a tension-free state (possibly with a slight counter pressure), the rods stick together again and the other outer layer can be applied.

With many types of veneer, however, this cross-splitting operation is superfluous because the veneer strips can be easily broken in their cutting or shaving plane when subjected to bending loads.

In a similar form, panels for lightweight construction can be produced from balsa wood, the core material preferably being composed of end grain panels cut flat, which can be cut lengthways and crosswise with blade shares before it is compressed again and connected to the outer layers.

In the case of thin plates with soft, but tensile outer layers, such as polystyrene foils, the blade can cover both the outer layers and the core material made of balsa, hard foams, paper honeycomb structures (e.g. Nomex), corrugated cardboard, wood fiber materials or the like To cut cut. With thicker panels it is possible to use some core materials as far cut so that the remaining thickness of the material can be broken through. Accordingly, segmentation of the inner layer or an easily breakable core material would not be necessary here.

Because of their lower rigidity, some such materials have to be specially stiffened in concrete formwork or can only be used for formwork boxes or the like. As far as nails are insufficient, other joining techniques are required.

A particularly light but resilient design has a core material made of tubes which, due to uniform pressing from all sides, come into horizontal mutual frictional engagement and thereby assume an almost hexagonal cross section. In the uncompressed state, they preferably have a round cross section with six evenly arranged, light beads or reinforcements or have e.g. hexagonal cross-section with convexly curved, almost circular outer edges, so that there are no cross-sections deviating from the desired polygonal shape during pressing, which can occur in round tubes due to material tolerances and uneven pressure. The advantage of this design is the low weight and the increased stability of the plate due to the horizontal prestressing of the core material. For formwork, however, this material should not be used with nails, but with other joining techniques.

In addition to cylindrical and cuboid segments for core material, even lighter elements are possible with the same load capacity, such as double cones or double T-shapes.

So-called honeycomb honeycomb structures made from extruded multiple profiles or from folded or stretched sheets, strips of impregnated cardboard or fiber plastics can also be used.

Honeycomb shapes made of blocks or rods with a hexagonal cross-section as core material are also possible; advantageously, every third element can be omitted without a substantial loss of stability, as a result of which the core material becomes lighter and material is saved. Another advantageous embodiment is the combination of blocks and rods of hexagonal cross section with uniformly round tubes, which provide a pretension when pressed together. The combination of different materials can be advantageous. The contact surfaces of the blocks provide a good bond with the outer layers.

The frictional, mutual connection of the individual elements of the core material results in high internal damping against vibrations. This damping can be influenced by the material and surface of the elements, in the case of tubes also by wall thickness, shape and pressure in the manufacture of the core material, as well as by lamination technology and the properties of the outer layers, and can be optimized as a function of frequency.

The division of the core material into individual elements ensures protection against the spread of cracks due to punctiform loads and possible damage in the core structure in all versions and therefore creates improved conditions for mechanical connection techniques such as rivets and screws, even for plates that are exposed to strong vibrations. Because injuries to the core material remain - even with blocks and rods - punctual and cannot spread, with pre-stressed tubes the damage to individual elements is also compensated elastically.

The use of rods and tubes in different colors, but especially the combination of tubes and rods and their sorting in a line and checkerboard pattern, in conjunction with transparent outer layers, also results in a marking to make dressing easier during processing.

With the solution, which uses a end grain board as the core material, it has surprisingly been found that such a panel can be divided at the interface just as easily as panels with the core materials described above, although the adjacent wood fibers along which the panel divides so easily leaves, come from a grown wood structure that was completely intact until the division. Since end grain wood panels are produced extremely rarely, the person skilled in the art completely lacks the experience that such a panel can easily be broken off, and exactly along a predetermined edge, without the breakage occurring instead or in addition elsewhere. This is only possible with the board according to the invention, in which the outer layers ensure the cohesion of the fibers, except at the point where at least one of the outer layers is cut so far that it breaks in the transverse direction when loaded. The end grain plate underneath, as tests have shown, breaks exactly along the cutting line, even if it should not run in a straight line. As already described, the outer layer below can be broken off by bending alone or cut in beforehand.

Of course, there have to be certain requirements for the quality of the end grain board if a clean break is to take place: so it is essential that there is no branch or twist in the end grain, because all fibers must be as straight and parallel as possible. Parts of branches can be easily cut out and repaired by gluing in faultless replacement pieces.

The size of a board is therefore only limited to the size of a end grain board, i.e. maxiaml to the cross section of a tree trunk. In order to remedy this limitation, it is proposed according to one embodiment of the invention that the end grain plate should consist of a number of individual end grain discs glued to the edges.

Such end grain wood panels of any size are produced by gluing square timber (wooden rods with a square or rectangular cross-section) to a large, solid wooden cube or cuboid. This is known in the art; The wood panels are cut, for example by means of a saw, but not, as usual, in the longitudinal direction of the squared timbers and thus the grain, but in the transverse direction.

It has surprisingly been found that the multitude of glue edges in such a end grain board clean them

Breakage in no way impaired or aggravated. So is it has become possible to produce a table according to the invention in almost any size. It is even possible to place or glue several butt-jointed end grain boards on one outer layer and to apply a second outer layer to this arrangement if a board is to be created which is larger than the end grain boards available. It may even be unnecessary to glue the abutting edges of the end grain boards together.

Basically, it is possible to use any wood for a end grain board. However, soft woods and among these balsa wood and especially spruce wood have proven to be unexpectedly suitable. Balsa wood results in a very light but high-strength panel that is particularly well suited for installation in vehicles (land, water and aircraft). Spruce wood is an inexpensive panel that is particularly suitable for formwork panels.

The outer layer can consist of a polystyrene film if the aim is to make it easy to remove concrete, for example, and to make it moisture-proof, for example for control panels, for external formwork, for formwork in sanitary rooms and kitchens or the like. But veneers are also suitable as an outer layer ; they will be used wherever the appearance of wood is desired, such as for interior panels in house and vehicle construction. It is also expedient to coat a board on the one hand with a veneer and on the other hand with a plastic film, for example in order to reduce the costs of a panel wall.

Since the end grain is relatively inexpensive and should not be too thin so as not to cause any problems during processing, the aim of the invention is to have a thickness of the entire panel of at least 10 mm and preferably of about 20 mm. This board can also be cut to size, for example in series production, by punching and folding, whereby even with a sheet thickness of 20 mm, a clean cut is made, in contrast to plywood, which can only be punched up to thicknesses of 2 mm, without requiring post-processing. The two parts of the punching tool create a notch in each outer layer, and the end grain plate divides without waste along adjacent elementary fibers, so that the end grain board cannot be frayed.

If a chipboard is used as the core material, it is chip material that is usually wetted with synthetic resin. By baking the synthetic resin, the individual chips stick together; this gives the chipboard its strength.

The known chipboard is manufactured either in the flat pressing process or in the extrusion process. In the case of chipboard produced using the flat pressing process, the elongated chips lie predominantly parallel to the two outer surfaces of the board, that is to say to the two large surfaces which run parallel to one another and are connected to one another by the narrow side of the board. At the same time, the chips cross each other in a statistical distribution, so that a plate is created which is sufficiently resistant to bending, for example to serve as a leveling, permanent covering for an uneven floor of a living space. In the extrusion process, the chips are oriented rather transversely to the outer surfaces, but still in a statistical, mutual crossover. The bending strength of such an extruded chipboard is significantly lower than that of a flat-pressed chipboard, which is why it is usually preferred. Up to now, it would have been nonsensical to produce a chipboard with only cross-oriented chips, because they consist of fibers that extend in their longitudinal direction and have good breaking strength, but only little mutual cohesion. A chipboard with only transverse chips would break when subjected to bending stress, since the cohesion of the fibers would give way. The fibers themselves, which ensure a certain flexural strength of the plates, remained ineffective. The connecting synthetic resin, which must also be inexpensive, makes up only a small part of the plate volume, so that it is not possible to compensate for the disadvantageous behavior of only cross-laminated plates by means of the synthetic resin.

However, the invention makes use of the property of only cross-laminated chipboard that can be easily and cleanly broken off by having such a chipboard with tensile strength on its outer surfaces

Outer layers coated, of which then under bending stress one absorbs the tensile load that occurs while the compression and shear forces are absorbed by the chipboard. Surprisingly, such a coating is sufficient to produce a composite panel with superior flexural strength, taking into account the completely inadequate chipboard, which also has the advantage that it can only be finished without leaving marks by scratching and kinking.

The chips are held together with a synthetic resin or, more generally, glue that hardens and thus holds the chips of the plate together. A glue is used, which becomes flowable when heat is applied, i.e. can be added to the chips as a non-adhesive, dry coating or as dry granulate or powder during the manufacture of the board, and then liquefies when heat is applied or solidifies again on cooling, whereby in in the liquefied state, the glue and chips combine and then hold together in the solidified state. In principle, it would also be possible to choose a cold-curing glue.

The chips are generally made of cellulose material, including rice straw or similar materials. Wood is preferred here, however, because its fibers have very little mutual cohesion; Such a chipboard with precisely transverse chips can be broken particularly cleanly, i.e. without any unraveling.

In addition, because wood is rigid, individual fibers cannot detach or spread apart from the neighboring fiber, as could be the case with flexible plant shavings.

Advantageously, grooves can be pressed into the surface of an outer layer of all of the described panels in a grid which, in the case of segmented core material, corresponds to the position of the outer edges of a group of elements and in which the blade is guided for cutting. If the strength of this outer layer which can be cut through in structures close to the edge is to be improved, projecting guide elements are preferred, for example narrow guide bands which are laminated parallel to one another and are laminated onto the surface. These can be over-laminated, coated or painted with a thin film, so that the tensile load can be speed of the outer layer is increased. This formation is not possible on the breakable outer layer.

Core material with rods, blocks and tubes as well as mixed layers can be produced efficiently because larger material packages can be pressed together, encased and then cut into finished core materials. However, a single-layer laminated board has even more favorable properties. The core material here consists of cup-shaped, preferably deep-drawn or blown elements with an almost square, rectangular or hexagonal base, which increasingly changes into a circular cross section towards the free edge. If they are arranged with their bottoms alternately up and down and then, as described for round tubes, pressed in such a way that their upper edge is geometrically shaped just like their bottom, these bottoms arranged alternately up and down provide a favorable connection surface for the outer layers, and there is also a pre-stressed core material. At the same time, the reciprocal arrangement of the cup shapes, as well as their possible different colors, make it easy to recognize the grid pattern for transparent exterior views.

For the simplified preparation of the boards with hand-held blade tools, especially with a knife, a marking grid already described is advantageous, or a printed grid similar to a graph paper, but with a centimeter or centimeter division.

A particularly favorable design is opened, for example, by embossing or deep-drawing a pre-stretched and relatively brittle set or embrittled primer with a corresponding edge structure and inserting it in molds in which hard plastic material is foamed, or by embossing these foils over quayander rollers foamed, semi-consolidated rigid foam sheets are applied in the strand, or that the core material is foamed directly between them. In these cases, the process can be controlled in such a way that the skin of the core material in this foaming process at the same time forms a good adhesive connection with the stamping film as the outer layer. However, the foils can also be applied with materials that simultaneously serve as lamination agents and for skin thickening. This means that the upper layers of open-pore or other core materials that are otherwise easily sheared off can be stabilized in one operation. Suitable are, for example, polyurethane glue or two-component PU foam glue (especially for lightweight panels) that penetrate the pores of the core material when the cover layers are pressed on.

In the case of chamfered blocks as the core material, it is advantageous to provide thermoplastic films, especially those made of polystyrene, after applying glue and preheating the outer layer by molding, for example with disc coulter rollers, as a surface structure as a cover layer that guides the blade hand tool easily along one Allows a series of blocks.

The invention also relates to methods for dressing and producing such a board.

Best way to carry out the invention

With regard to the production of such a board with a chipboard as the core material, it would initially be obvious to perfect the closest known method (extrusion process for the transverse alignment of the chips) to such an extent that all chips are aligned parallel to one another and only in the transverse direction.

The above-mentioned methods for electrostatically aligning the chips during the production of a chipboard have not become established because their implementation in the case of boards of customary dimensions encounters insurmountable difficulties: because of the length of the boards, extremely high voltages are necessary to stay on the machine Makes people impossible because of the high risk of rollovers. It would be conceivable to produce narrow plate segments and then to assemble them into plates, but a mutual influencing of the electrically charged chips of adjacent segments and thus the disturbance of their position cannot be prevented because of the Glue of the segments when joining them must still be flowable and therefore the position of the chips is not sufficiently fixed.

In contrast, in the method proposed by the invention, the electrostatic orientation of the chips is used, but in the transverse direction of the plate. The electrode spacings therefore do not need to significantly exceed the plate thickness (preferably not more than 20 mm). A voltage of the order of 20 kV is sufficient. Such tensions can still be managed with simple means. Since the length of the electrical field is significantly less than the dimensions of the machine and the electrical field only has to be far inside, a rollover on the outside is excluded.

The method of the invention consists in producing a loose bed or a mixture of solidified glue and chips embedded in them, optionally also of chips and glue powder or glue granules, which are only loosely connected, dry chips aligned transversely to the course of the outer surfaces, which are connected to each other by the narrow sides of the chipboard (i.e. perpendicular to the outer surfaces), the chips are pressed together and thereby fixed in their position, while the glue is liquefied by pressure and, if necessary, by the application of heat, this adhering, constantly updated mass forming the core of the Table forms, and an outer layer is laminated onto the outer surfaces of the core. The sticky outer surfaces of the core are covered by the lamination, so that the resulting panels can be handled and stacked without damage until the glue has completely cooled and hardened.

This method not only absolutely has to be used for the production of the corresponding quick-assembly and formwork panel, but it is also possible to omit the last feature of the method (laminating the outer layers) or to carry it out later and thus a chipboard as an end product by the method of the invention in which all the chips are aligned perpendicular to the outer surfaces of this particle board. Such chipboard can, for example, in the usual Use as inner door layers, result in a higher sound insulation than that of conventional extruded panels, because their bending stiffness is equally low in both bending directions. However, as long as the glue is still sticky, this chipboard requires certain protective measures during handling and storage. These protective measures are known to the person skilled in the art.

The chips coated with dry glue, if appropriate also chips and dry, powdery or granulated glue, the chips being present in the most varied of directions, are preferably introduced into a molding channel, the cross section of which essentially corresponds to that of the chipboard to be produced. Now, while the chips are still loosely distributed and thus freely movable with respect to one another, an electrical direct current field or an electrostatic field is created from outer surface to outer surface, so that the chips begin to align in the direction of the field lines. Since the glue is still hard, it does not hinder the chips in this orientation. This loose mixture with aligned chips is then compacted so that the chips are reliably fixed in their position by the friction on the neighboring chips.

The glue is then liquefied by pressure and possibly heat, which firmly connects the chips to one another, thus maintaining the shape of the core produced in this way.

In principle, it would be possible to align the loose chips in advance and then introduce them continuously and continuously into the molding channel. According to an embodiment of the invention, however, it is preferred that the glue-coated chips or the chips and a glue powder or glue granulate are introduced into the molding channel, in which a piston also moves. As long as the piston is retracted, the shaped channel, possibly also its inlet, offers enough space for the loose mixture of chips so that they can align themselves in the electrostatic field. If the piston presses into the mold channel, it compresses the aligned chips, fixes them in this way and the glue begins to liquefy.

The application of glue and chips takes place discontinuously, but this is an advantage: there is an optimal speed for the conveying through the forming channel. Aligning the chips, on the other hand, requires a time dependent on other boundary conditions, such as the ambient temperature. It is now relatively easy to set the stroke of the piston after the time required for alignment, but its speed always remains optimized after being conveyed through the molding channel. This would not be possible with continuous loading and continuous pressurization since the conveying speed through the molding channel would depend on the alignment process.

The invention proposes in a further development that the molding channel is only very short and is arranged in such a way that the setting chipboard is discharged vertically downwards. This means that no transverse loads act on the chipboard, which is still deformable after leaving the short molding channel. In particular, spontaneous breaking of the chipboard is avoided, which is not yet loadable in the transverse direction because it is not yet provided with the outer layers.

The invention also proposes a preferred device for carrying out the method described above.

The main characteristic of the associated devices is electrodes, with which the loose chips are aligned transversely to the main surfaces of the plate. The chips are then compacted in this position and glued together.

A currently particularly preferred device has a shaped channel with a rectangular cross section, which corresponds to the cross section of the chipboard to be produced. This chipboard is the core of the formwork panel according to the invention. The molding channel has an inlet for the glue-coated chips or a mixture of chips and glue in the form of powder and granules. The shaped channel is arranged essentially vertically, with the outlet opening pointing downward.

Wear inserts are arranged in the molding channel on the opposite walls, which correspond to the outer surfaces of the chipboard to be produced. These wear inserts reach right up to the inlet and offer a selected friction compared to the material that is pressed through the molding channel. resisted so that the material can be compacted. The locking inserts wear out during operation and are regularly replaced.

Furthermore, electrodes are arranged on both sides of the molding channel, which align the loosely poured chips in parallel and perpendicular to the main surfaces of the molding channel.

Here, the wear inserts cannot consist, as is customary, of steel sheets, but rather of electrically insulating material, preferably ceramic material, in which electrodes are embedded. These electrodes are then surrounded on all sides by the insulating material and are therefore not in galvanic contact with the material located in the molding channel.

The electrodes preferably extend only over the part of the molding channel closest to the inlet.

The molding channel is heated to make the glue flowable in conjunction with the pressure applied to the material in the molding channel when the chips are already aligned. Finally, an electrostatic high voltage direct current source is provided that generates a voltage that is applied to the electrodes in the wear inserts. This voltage can be a few tens of kilovolts. The current flowing is low.

A piston, the cross-sectional area of which essentially corresponds to the inner cross-sectional area of the molding channel, can enter the molding channel through the inlet, take material from the inlet with it and compress it between the two wear inserts.

When the piston has retracted, there is initially a free space in the molding channel into which the bed of glue-coated, dry chips is loosely introduced. These chips are therefore mobile and can be aligned along the field lines due to the strong, electrostatic field. However, the prerequisite is that the glue is not a particularly good electrical conductor. This requirement is met with all common synthetic resins. This bed is then compacted, the glue is liquefied and a strand of compressed chips glued with glue emerges vertically downward through the outlet opening, the dimensions of which correspond to those of the chipboard to be produced. The chips are all aligned perpendicular to the two opposite outer surfaces. In the course of the downward movement, the strand can be gently deflected into the horizontal, in order then to be coated on both outer surfaces.

The inlet is preferably widened in a funnel shape. A piston is provided, the cross section of which corresponds approximately to the inner cross section of the molding channel. This piston is set up to dip into the mold channel and to move out of it again.

Brief description of the drawings

The invention is explained in more detail in the following schematic drawing; in this shows:

1 the principle of the stability of sandwich panels,

2a-e the process of finishing a plate according to the invention,

3 shows an embodiment of the core material,

4 shows another embodiment of the core material,

5 shows a further embodiment of the core material,

6 shows a marking grid on the outer layer,

7 shows a marking grid on the core material,

8 shows a further embodiment of the core material, 9 shows yet another embodiment of the core material and its production,

10 three versions of elements for the core material,

11 shows a further embodiment of the core material,

12 shows an element of the core material of FIG. 11,

13 shows a further embodiment of the panel according to the invention,

Fig. 14 in a highly simplified representation a sectional oblique view of a device for producing a chipboard or a core of a formwork panel, when loading, and

Fig. 15 is a view as in Fig. 14, but during compression.

1 shows how, when loaded with a force moment 1 against the supports 50, 51, a tensile load 52, 53 is exerted on the lower outer layer 3 and a compression moment 54, 55 on the upper outer layer and the upper side of the core material 4. The tensile strength of the core material 4 is relatively insignificant, including the fact that the strength of the board is not significantly less with segmented core material 4 than with undivided core material.

2a-e illustrate the process of preparing a board. After the surface of the board 1 has been cut in the direction 13 in FIG. 2a with a knife 12, it is counteracted in FIG. 2b by pressure on the outer regions 14 and 15 a support (e.g. the knee of a worker) under the cutting edge 16 is loaded so that the core material 17 breaks through it. If, as shown in FIG. 2c in view and in FIG. 2d in detail, the sides of the table 14 and 15 are placed against each other with their back, the outer layer 11 bends at the bend 17 until it breaks. The result is the two neatly separated parts 18 and 19 (Fig. 2e). Fig. 3 shows a core material made of rectangular blocks 6, which are chamfered in the peripheral layers (11) so that when a plastic deformable outer layer is applied there is a marking grid through which the position of the blocks 6 or rods can be seen from the outside, and through which the separating tool can be guided along the edges of a row of elements 6 of the core material in the resulting joint.

FIG. 4 shows a core material made of very thin rods 25, the maximum tolerance of the position of the breaking edge 27 with respect to the cutting edge 26 being the rod diameter 28. Here the finished plate can also be cut at any point and at any angle 29. However, breaking through becomes more difficult in this embodiment because the gluing up to half a bar width 28 must also be removed. In addition, the broken edges become less clean because, after being trimmed by breaking, narrow remaining strips of the outer layers can protrude beyond the core material 4.

5 shows an embodiment with veneer strips 56 lying next to one another as the core material, the strips being cut transversely to the fiber direction 57 and therefore being able to be easily broken in the region of the path 61 when there is a bending load between the supports 58, 59 and the pressure vector 60.

6 shows how, with the aid of strips 30 and / or threads 31 applied to the outer layer, marking grids are produced which can be used when guiding the finished sheet as a guide for blade knives or other blade hand tools.

7 shows differently colored blocks 6 or rods 7 or veneer strips which are arranged with their end faces 31 in a cell-like or checkerboard manner and thus form a marking grid 9 which is visible through a transparent outer layer 2a, 3a made of PMMA, PS or GRPs.

Fig. 8 shows a structure with honeycomb elements made of solid material 35, in which every third element is either recessed to save weight and material, or by in hexagonal cross-sectional shape pressed, originally round tubes 37 is replaced to bias the structure of the core material 33.

FIG. 9 shows an embodiment in which tubes (18) with a cross section going from the circle to the hexagon are pressed together by horizontal pressure from all sides 38, 39 to form an almost hexagonal basic shape (40) and have a frictional connection 41 with one another.

Fig. 10 shows three versions of the basic shape of such elements with bead 42, reinforcements 43 and hexagonal / convex cross-section 44, each ensuring that even when pressing many elements and with possible material and dimensional tolerances, hexagonal cross-sections always arise.

11 shows an embodiment with oppositely arranged cups 45, 46, the manufacture of which is preferably carried out by blowing or deep drawing, and which are mutually arranged 49 with their bottom 47, which is almost square here, at the top and bottom. They are pressed in both horizontal directions in such a way that their edge 53 assumes an almost almost square shape as does their base 51. The resulting checkerboard-like grid 9 can also serve as an orientation aid when cutting by different colors and corresponding arrangement of the so distinguishable bases .

12 shows the elements of the core material which are suitable for this structure: cups with an almost square base 51 and the rim 53 which is circular in the uncompressed state.

Fig. 13 shows an oblique view of a panel according to the invention with an upper outer layer 102, part of which has been omitted for the sake of clarity, and a lower outer layer 103. Each of the outer layers is designed as a thin, flat plate made of veneer or polystyrene, which both are parallel to each other and have a distance of almost 20 mm between them. Between the outer layers 102, 103 there is a core plate which is designed as end grain plate 104 and in which all fibers are parallel to one another and run perpendicular to the two outer layers 102, 103. The end grain board 104 is glued to both of its end faces with one of the outer layers. The end grain panel 104 consists of individual panel elements which are assembled in a modular manner and, if appropriate, are glued to one another at their abutting edges. These edges are not shown in the drawing.

In the device shown in FIGS. 14 and 15, two mutually parallel heating plates 204, 205 form the walls of a molding channel. These heating plates 204, 205 have a horizontal length which corresponds to the side length of the plate to be produced. The upper part of the mutually facing surfaces of the two heating plates 204, 205 is coated with a wear plate 208, 209, respectively. These wear plates 208, 209 are made of electrically insulating, ceramic material; Electrodes 210 are embedded in the middle of this material and without contact with one of the main surfaces of the wear plates 208, 209. These electrodes 10 are connected to a power supply (not shown).

The upper edges of the heating plates 204, 205 are chamfered downwards and towards the molding channel and thus form a trough-shaped inlet, into which material 2, which consists of resin-coated chips, is placed in the cold state. An arrow shows the direction of loading of the chips.

A piston 206 which fits exactly into this is arranged above the molding channel and is raised in the illustration in FIG. 14 (see arrows). An incidence space 203 is created between the underside of the piston 206 and the upper mouth of the molding channel, which is loosely filled with material 202, as is the compression space 207, which is arranged under the incidence space 203 between the two heating plates 204, 205 near their inlet .

On the upward stroke of the piston 206, the incident space 203 opens, so that material 202 can flow loosely into the compression space 207 through it. There is a strong, electrostatic field, which is applied by applying a voltage of preferably about 20 kV to the electrodes 10, and aligns the still cold and therefore non-sticky, loose chips in the direction of the field lines. During the downward stroke of the piston 206 (FIG. 15 - see arrows), the loose material 202 located in the compression space 203 (FIG. 14) is compressed and pressed further down. Due to the pressing pressure, but primarily due to the heating effect of the heating plates 204, 205, the material is heated so that the resin coating the chips melts. The chips, which have already been aligned, are therefore no longer movable relative to one another, the molten resin possibly being effective as a fixing agent due to its high viscosity.

During the downward movement of the piston 206, a particle board 201 emerges vertically downward, which begins to solidify as it descends, but is still warm and therefore remains sticky. It is therefore easy to laminate an outer layer onto both outer surfaces of the particle board. Due to the outer layers, the finished formwork panel can already be processed and stacked without breaking, deforming or sticking together with another formwork panel. After several days, the final strength of the chipboard or the core of the formwork panel is achieved.

The dimensions shown are preferred guidelines. Depending on the circumstances, other values can also be advantageous. For example, it is possible for the electrodes 210 to extend into the region of the molding channel in which the resin wetting the chips has already solidified, so that the chips have no opportunity to leave their orientation which they have been given by the electrostatic voltage .

When cutting this formwork panel, only one outer layer needs to be cut. Then the two edges of the separation point form a ruler, along which the core material (the chipboard) can be broken off cleanly. The outer layer remains firmly glued to the chipboard on both sides of the separation point. A predetermined breaking point is thus formed in the opposite outer layer, which breaks off after bending and kicking back. Industrial applicability

The invention is primarily intended for use as a rapid construction board in the building industry. This results in advantages in the rational preparation of elements for formwork, partitions, floor boards, etc., in particular. by avoiding long distances to the location of a circular saw. The material should also be interesting for craftsmen who are not otherwise involved in woodworking and do not have the appropriate processing machines, such as locksmiths (for fillings of metal frames), plasterers and painters, roofers and bottle-makers, who can use them to carry out auxiliary structures and cladding.

Caretakers and other skilled trades can use it to carry out repairs and provisional facilities. A correspondingly extensive market arises for do-it-yourselfers who can manufacture simple furniture, cladding and furnishings without the use of expensive and dangerous machines, without dirt and noise.

A preferred application also arises in schools and kindergartens because children can make solid objects themselves with the use of blades with low sharpness and depth of cut without risk of injury and without further technical equipment.

The plate offers joiners and shopfitters the advantage of being able to be roughly cracked on the storage rack in order to avoid the transport of entire plates to the circular saw and back. When used in trade fair and shop construction, in addition to rational preparation, the avoidance of dust, dirt and noise is particularly important when work is still required in the customer's ongoing operations. In addition, you can operate in a relatively small area.

Decorators and interior decorators, set designers, showmen and open-air organizers see similar advantages.

A particular application can arise for aid programs in third world countries, where both tools for woodworking and their proper use have not yet been widely used.

Claims

claims

1. Dressable quick-assembly and formwork panel in sandwich structure, made of a core material that is crush and shear test and coated on both sides with a tensile outer layer, characterized in that at least one of the outer layers (2, 3) with a blade hand tool according to the desired Dressing can be severed, the core material (4), roughly following the cutting edge, can be broken off cleanly and at least the other outer layer can be cleanly broken off after kinking.

2. Board according to claim 1, characterized in that the core layer is formed from a end grain board (104), the fibers of which run perpendicular to the outer layers (102, 103).

3. Board according to claim 2, characterized in that the end grain board (104) consists of individual end grain discs glued together at the edges.

4. Board according to one of claims 2 or 3, characterized in that the end grain plate (104) consists of balsa or spruce wood.

5. Board according to claim 1, characterized in that the core material is formed as a chipboard (201) with only cross-oriented chips, which are held together with a glue that becomes flowable when heated.

6. Board according to claim 5, characterized in that the chips consist of wood.

7. Board according to claim 1, characterized in that the core material (4) consists of rigid foams, cork or bound, fibrous and / or granular material.

8. Board according to claim 1, characterized in that the core material (4) consists of individual, closely spaced and optionally pressed together elements or consists of slotted material which or only with the outer layers (2, 3) are firmly connected.

9. Board according to claim 8, characterized in that the elements for enabling any separation point consist of thin pins, or fibers or straws or chips.

10. Board according to claim 8 and 9, characterized in that the elements of the core material consist of wood shavings or vegetable fibers, which are arranged perpendicular to the outer layers and only pressed together or slightly connected, but firmly connected in the peripheral zones of the core material and with the outer layers are, wherein the length of the chips or fibers preferably corresponds to the thickness of the core material.

11. Board according to claim 8 and 9, characterized in that the elements of the core material consist of non-combustible mineral fibers, which are preferably arranged perpendicular to the outer layers and in addition to a light bond with each other in the edge zones (5) by a preferably made of foam or adhesive existing layer are connected to each other as well as to the outer layers (2, 3), the length of the fibers preferably corresponding to the thickness of the core material.

12. Board according to claim 8, characterized in that the elements consist of juxtaposed veneer strips cut transversely to the fiber.

13. Board according to one of claims 8 or 9, characterized in that the elements of the core material consist of light, pressure-resistant and shear-resistant materials, preferably of sawn or pressed wood, hard foam with skin or lightweight concrete, Plastic regenerates or pressed plastic waste, and more preferably made of tubes (18) or cups (45, 46) made of plastic or metal, which are preferably pressed together under pressure.

14. Table according to one of claims 8 to 9 and 13, characterized in that the elements are prismatic or conical bodies, which preferably have a rectangular cross section parallel to the outer layers, and that this body is tightly packed or pressed into one another.

15. Board according to claim 8, characterized in that the elements of the core material as blocks (6) or rods (7) with a square, rectangular or the same, regularly hexagonal cross section are formed.

16. Table according to claim 8 and 15, characterized in that between the elements with a hexagonal cross section after at least and preferably two adjacent elements, a dimension corresponding to an element blank space (36) is provided to save mass.

17. Board according to claim 16, characterized in that in at least some of the empty spaces (36) a tube (18) is inserted, which is resiliently deformed by pressing the elements together to form the hexagonal cross section of the empty space (8) and thus the core material ( 4) communicates an internal preload.

18. Table according to claim 8, characterized in that the elements are designed as deformable tubes (18) which correspond to approximately round cross-section and distributed six longitudinal beads (42), longitudinal reinforcements (43) or longitudinal flats on their wall evenly over the circumference and that the tightly packed tubes (18) are deformed into an approximately hexagonal cross section by being pressed together in two mutually perpendicular directions (38, 39) parallel to the outer layers (2, 3).

19. Panel according to claim 8, characterized in that the elements of cups (45, 46) widening towards the edge (50) with hexagonal or square bases (47) and approximately round edges (50) are formed, which are successively placed against each other and pressed together so far that each edge (50) fits closely to the contour of the four or six floors surrounding it.

20. Board according to claim 7 and 13, characterized in that the edge zones (5) of hard foam core material to improve the shear strength of the outer layers (2, 3) are compressed.

21. Board according to claim 20, characterized in that the adhesion and compression of the edge zones (5) of the foam in thermosetting foams is preferably effected by the use of foam adhesives, in thermoplastic foams by heated pressing of the cover layers, which can also be selected when suitable materials are selected connect without glue.

22. Panel according to one of the preceding claims, characterized in that at least one of the outer layers (102, 103) consists of a veneer or a polystyrene film.

23. Table according to one of claims 1 to 21, characterized in that the outer layers (2, 3) made of sodium kraft paper or hard cardboard or thin veneers, the latter glued together at an angle, are formed and with greater deflection without the formation of needles or injuries Break through the teeth at the break points.

24. Board according to claim 21, characterized in that the outer layers (2, 3) made of plastic films, preferably made of transparent plastic, impregnated and / or coated fabrics or felts, but in particular fiber plastic.

25. Board according to claim 1, characterized in that the outer layers (2, 3) are of the same design.

26. Panel according to claim 1, characterized in that the cut through outer layer (2) is reinforced by ribbons and fiber strips.

27. Panel according to one of claims 1 to 26, characterized in that the breakable outer layer (3) consists of a thin but hard and pressure-resistant layer, e.g. a thin hardboard, a tempered veneer or a structured hard plastic such as Melamine resin.

28. Panel according to one of the preceding claims, characterized in that the outer layer (2) which can be cut through has a marking grid (9) or guide grooves which is visible from the outside.

29. Board according to claim 28, characterized in that the lines of the marking grid (9) or the guide grooves (12) correspond to a division between the elements of the core material.

30. Table according to one of claims 28 or 29, characterized in that flat, narrow strips (6) are applied adjacent to each other so on the outer surface of the outer layer (2) that can be cut through that the adjacent edges of two adjacent strips (6) have a guide groove form for guiding a cutting tool.

31. Panel according to claim 30, characterized in that the strips are tensile and thus form a stiffener.

32. Panel according to one of claims 1 to 31, characterized in that the outer layer (2) which can be cut through is so far translucent or transparent that the position of the elements of the core material (4), in particular the blocks (6) or rods (through them) 7) is recognizable.

33. Table according to claim 32, characterized in that the surface of the core material (4) facing the transparent or translucent outer layer (2) carries a grid, which is preferably formed by the differently colored ends of the elements of the core material.

34. Panel according to one of the preceding claims, characterized in that the thickness of the panel is at least 10 mm and preferably about 20 mm.

35. A method for dressing a rapid construction and formwork panel according to one of claims 1 to 34, characterized in that the cutable outer layer is cut through, the rest of the panel is kinked, the core layer being kinked or split, and finally the other outer layer is broken off .

36. A method of dressing a quick-assembly and formwork panel according to one of claims 1 to 34, characterized in that when the outer layer which can be cut is cut through, the core layer is also cut or cut through.

37. A method for producing a rapid construction and formwork panel according to one of claims 1 to 34, characterized in that the panel is punched out of a larger plate or separated from a larger plate by folding.

38. A process for producing a cross-laminated chipboard coated on both sides, preferably according to one of claims 5 or 6, characterized in that a loose bed of dry glue and chips embedded in this is produced, the chips are aligned transversely to the course of the outer surface, the are connected to the narrow sides of the particle board, the bed is compressed into a core by the action of heat and pressure, and the outer layers are laminated onto the core on both sides.

39. The method according to claim 38, characterized in that the bed is introduced into or produced in a molding channel, the cross section of which essentially corresponds to that of the chipboard to be produced, and an electric field is applied to this molding channel so that the chips are transverse to the course of the outer surfaces.

40. The method according to claim 39, characterized in that the molding channel is heated, and that glue-coated chips or chips and glue powder or chips and glue granules are introduced discontinuously into the molding channel and heated after alignment and moved forward by means of a piston.

41. The method according to any one of claims 39 or 40, characterized in that the still formable chipboard leaves the molding channel, preferably as an endless web, vertically downward, is coated on the two opposite outer surfaces and is divided into length sections, which are deposited for cooling and solidifying the core become.

42. Device for carrying out the method according to one of claims 38 to 41, characterized by the following features: a shaped channel with a rectangular cross-sectional dimension substantially corresponding to the cross section of the chipboard (201) to be produced, which has an inlet for glue-coated chips or at the upper end Chips and glue powder or glue granulate and forms an outlet opening at the lower end,

Wear inserts (208, 209), which are inserted into the opposite walls (204, 205) of the molding channel that define the outer surface of the chipboard (201) and preferably reach up to the inlet,

Electrodes (210) insulated on either side of the mold channel, a heater for heating and liquefying the glue covering the chips in the mold channel, and a high voltage direct current source connected to the electrodes (210) so that the electrodes (210) one of the opposite wear inserts (208, 209) are each connected to a pole.

43. Apparatus according to claim 42, characterized in that the wear inserts (208, 209) consist of electrically insulating material and that the electrodes (210) are embedded in the wear inserts.

44. Device according to one of claims 42 or 43, characterized in that the inlet is widened in a funnel shape to receive a load (202) of glue-coated chips or chips and glue, and that a piston (206) is provided which is set up for this purpose to push the load (202) in the inlet into the forming channel and to compress it there after aligning the chips.