FR2774621A1 - PROCESS FOR MANUFACTURING FOLDABLE FIBER PANELS - Google Patents

Abstract

The invention relates to a method for manufacturing foldable fiber panels, which have at least one face (4) exposed to view, with at least two parts of fiber panels (2a, 2b) which are connected to one another. 'other, along a connecting edge (8a, 8b), by a connecting element (16). The method of the invention comprises the following steps: separation of a fiberboard into at least two parts of fiberboard (2a, 2b), by means of a separation cut, placed one on the other of the two parts of fiberboard (2a, 2b), the faces (4) exposed to the view being turned towards each other, alignment with flat surfaces of the parts of fiberboard (2a, 2b) at least the along the connecting edges (8a, 8b) to which the connecting element (16) will be fixed, removable fixing of the two parts of fiber panels (2a, 2b), machining of the connecting edge (8a, 8b) on each of the parts of fiber panels (2a, 2b), mounting, and if necessary hardening, of the connecting element (16). Application to foldable fibreboards.

Description

PROCESS FOR MANUFACTURING FOLDABLE FIBER PANELS

  The invention relates to a method for manufacturing foldable fiber panels which have at least one side exposed to view. Fiber panels are understood to mean, for example, all panels manufactured using lignocellulosic fibers, for example hard fiber panels or medium density fiber panels. Such panels are used, for example, as rear cabinet walls. 25 The rear cabinet walls have long been constructed from individual fiber panels which were bonded and secured to each other by means of separate binding. To minimize handling of individual parts, however, attempts have been made for some time to manufacture

  rear walls of removable cupboards which can be fitted without any additional means.

  Known methods of continuously manufacturing parts of panels connected to each other are for example described in DE-C-838 361 and DE-A-4 418 274. It is common to both methods that they can be integrated into continuous manufacturing processes. This is a condition

  absolute to be able to offer these mass items at minimum prices, without unnecessary manipulation.

  It has been proposed, in DE-C-838 361, to first provide grooves with a panel, from which the parts of fiber panels to be connected to each other must be made, the grooves then being covered by an element link. Then the bottom of the groove is removed by milling and the parts of individual panels to be connected to each other are arranged on a connecting member. This manufacturing process is unsuitable for the production of rear walls of furniture because it cannot be used for panels having at least one face exposed to view because, during the implementation of the process, both

panel surfaces are machined.

  DE-A-4 418 274 describes a process suitable for the production of folding rear walls of furniture, that is to say of fiber panels having at least one wall exposed to view. In the case of this process, which is inspired by the working steps of DE-C-838 361, a groove is also cut first, then the connecting element is mounted25 and, finally, the bottom of the groove is separated by machining from the visible side. The panel parts connected by the connecting element are then folded back so that the visible faces are turned towards each other. This process is very costly to implement. It is difficult to machine the fiberboard on the visible side without damaging the groove with the connecting element without damage to the visible side of the fiberboard or to the connecting element . The folding of the fiber board parts after assembly of the connecting element and the milling of the second groove often already lead to

damage to the connecting element.

  It is therefore the object of the invention to provide a

  simple and economical process for the continuous production of foldable fiberboard.

  To this end, the subject of the invention is a method of manufacturing foldable fiber panels, which have at least one face exposed to view, with at least two parts of fiber panels which are connected to each other. , along a connecting edge, by a connecting element, characterized by the following steps: - separation of a fiberboard into at least two parts of fiberboard, by means of a separation cut, - laying one on the other of the two parts of fiberboard, the faces exposed to the view being turned towards each other, - alignment on flat surfaces of the parts of fiberboard at least along the edges of connection on which the connecting element will be fixed, 20 - removable fixing of the two parts of fiber panels, machining of the connection edge on each of the parts of fiber panels, - mounting, and if necessary hardening, of the 'element of

liaison.

  The starting material for the production of

  Foldable fiber is a fiberboard made by a continuous process, coated or otherwise provided with a modification on at least one side. The face, coated for example with lacquer or decorative paper, will be called

  after face exposed to view or visible face. The second side, most of the time uncoated, of the fiberboard will be called hereinafter. 35 The starting fiberboard, from which the foldable fiberboard is to be made, is first separated into at least two parts of fiberboard by a separation cut. The cutting can take place both from the visible side and from the reverse. The two parts of fiber panels are then placed one on top of the other using suitable turning devices, for example using a turning star or a lever device. The faces

  visible parts of the fiberboard are then turned towards each other.

  This step of completely separating the individual starting fiberboard and the subsequent inversion of the fiberboard parts is new and extremely unusual in the context of subsequent machining of fiberboards for furniture parts. The operations followed up to now have always avoided such a stage because the turning and dressing of the parts of the panels appears to those skilled in the art as a complicated, expensive and space-consuming intermediate stage. On the contrary, it has been preferred, until now, to carry out the subsequent machining as much as possible in a plane, without interruption, on continuous or chained conveyor devices, and not to bend the parts of the panels. only after assembly of the connecting element. Any interruption or even manipulation of parts of panels was seen as a measure lowering the efficiency of the installation.

of production.

  However, it has proved very advantageous, during tests, to carry out the manufacture of foldable fiber panels by following the sequence of steps according to the invention. A separation cut, by which the starting fiberboard is completely separated into two parts of fiberboard, can be made with a simple saw to adjust. The expensive adjustment of a precise cutting depth, which is necessary for the formation of a groove, is not useful here. If the cut is made from the visible side, damage to the visible side at the cutting edge is considerably prevented because the saw comes out from the back of the fiberboard and any resulting chips in the area of the edge produced by the cut are on the back. A particular advantage of this method further lies in that rectilinear edges are formed, which do not require additional machining. These edges, hereinafter called external edges, are found after turning against the abutment. The edges located outside in the starting fiber panel10, hereinafter called bonding edges, can then be machined, in accordance with the method of

  the invention in such a way that not only can the connecting element be mounted, but also that the parts of finished panels have exactly the predefined dimensions.

  The panel parts can be turned over with the simplest means, the panel parts being freely movable and easy to handle. On the contrary, the folding of the panels according to the process described in DE-A-4 418 274, must be carried out with great

  accuracy, i.e. achieved by means of machines adjustable with corresponding accuracy, in order to ensure that the panels are not moved relative to each other in sliding, which would damage the element liaison.

  The fiberboard portions are then aligned with planar surfaces so that they can be joined to each other along a connecting edge. The alignment of the panel parts is carried out using simple stops on which the at least two panel parts are aligned by means of transport devices. As already explained, the parts of the panels are aligned with the stops by the external edges produced by the separation cut. The edges which are located outside in the starting fiberboard, that is to say the connecting edges, are accessible to subsequent machining devices thanks to this alignment. The parts of aligned fiber panels with flat surfaces are then detachably fixed, so that they remain in a relative position defined for the following machining steps. It is preferred to fix the fiberboard parts,

  after alignment, by means of a clamping device. Suitable clamps are, for example, pairs of spring-mounted rollers which exert pressure on the parts of the fiberboard arranged one on top of the other.

  Then, the fiberboard parts are machined along the connecting edge. In the simplest case, the connecting edge is chamfered from the reverse to the visible side in order to create a good adhesion surface for the connecting element. It is however also possible to profile the connecting edge, for example when the connecting element must close with flat surfaces on the plane of the reverse. An advantage of this procedure is that these working steps can be continuously monitored optically and that adjustments and changes to the setting can be easily carried out because the necessary machining devices are arranged laterally and are therefore easily accessible. In the case of the prior art method described above, the fiberboard is machined transversely to the direction of transport over the entire width of the transport path or respectively in the middle of the transport path and of the milling cutters and devices application of glues or the like is necessary both on the side of the visible face and on the side of the reverse. In the case of the process according to the invention, all the machining devices are arranged laterally with respect to the transport path because only the connecting edges of the parts of the fiber panels have to be machined since the outer edges are already completely machined. A particular advantage of the process according to the invention must be seen in the fact

  that, with the successive machining of parallel edges of parts of individual fiber panels added to one another, the predefined dimensions and angles5 can be respected with precision and with minimal expense.

  If necessary, the connecting edge is, after machining,

  still prepared for mounting the connecting element, for example by applying a varnish or an adhesive component.

  Finally, the connecting element is mounted. In the simplest case, an adhesive is mounted as a connecting element, preferably a synthetic adhesive based on polyurethane. Such adhesives are presented in the form of fusion adhesives, for example a polyurethane adhesive having a viscosity of 22,500 7,500 mPa.s at 120 C and a treatment temperature of 120 0C at 140 C. It is however also possible to use any simply a strip, if necessary provided with glue, for example a strip

  woven or a ribbon of film, as a connecting element.

  Depending on the adhesive used, the fiberboard parts are kept fixed until the adhesive is hardened. If necessary, the fiberboard parts pass through, at least in the region of the connecting edge provided with the connecting element, a device for hardening the adhesive. 30 After mounting and, if necessary, hardening the connecting element, the fixing device is loose and the foldable fiberboard is then immediately ready to be shipped without further handling being necessary. It is advantageous in this case that the visible side is protected against damage or soiling from the start of the machining. Drip glue, dust or damage from 8 saws or cutters on the visible side are

  excluded with the process according to the invention.

  Depending on the design of the production installations, the devices for implementing the process are either fixed or mobile, so that the parts of the fiber panels are machined continuously or in a fixed position (by cycles). In view of the higher yield in the case of continuous production by means of conveyor paths, the devices for carrying out the process, the clamping devices, saws or milling cutters for machining the edge The connecting elements and the devices for mounting the connecting element are preferably mounted fixed and the panel parts are moved in front of these devices. It may however also prove useful to move the devices for the implementation of the method.

  and the fiberboard parts in the same direction or in the opposite direction.

  Examples of embodiments of the invention will be described below in detail, with reference to the accompanying drawing in which: FIG. 1 is a perspective view of two parts of fiber panels after separation, FIG. 2 is a view in perspective of two parts of fiber panels arranged one on the other and aligned, FIG. 3a is a perspective view of two parts of fiber panels machined on a connecting edge, FIG. 3b is a perspective view of two parts of fiberboard machined on a connecting edge, Figure 4 is a perspective view of two parts of fiberboard connected by a connecting member allowing for folding, Figure 5 is a side elevational view of two parts of fiberboard connected by a synthetic glue, in the folded state, FIG. 6 is a side elevation view of two parts of fiberboard connected by a synthetic glue, in the folded state é, Figure 6a is a side elevational view of two parts of fiberboard connected by a synthetic adhesive, in the deployed state, and Figure 7 is a side elevation view of two parts of fiberboard connected by a bandaged

bonded textile.

  The continuous manufacture of foldable fiberboard, which is used in particular as the rear wall of furniture, is directly related, in general, to the manufacture of an endless strip of fiberboard.25 The fiberboard without end coated on at least one face has a width at least equal to the maximum width of the rear walls of furniture and has a thickness between 1.5 mm and 8 mm. The endless fiberboard is cut to the length necessary for the rear walls of furniture by means of separation saws. The fiberboard, shortened to the appropriate length, must then, if necessary, be further cut to the appropriate width. To achieve a convenient transport dimension, in particular for furniture presented in 35 ready-to-assemble flat packs, the fiberboard must often only have half the width of the furniture. Therefore, the fiberboard must be made foldable. The manufacturing process for such foldable fiberboard must, as a continuous process, allow the manufacturing

  simple and economical in large quantities.

  FIG. 1 represents two parts of hard fiber panels 2a, 2b, with a thickness of approximately 3.5 mm, which are coated with a decoration paper on the visible face 4. The reverse side 6 is not machined and not coated. The parts 2a, 2b have, after separation, external edges 10, 12 facing each other. The outer edges 10, 12 are, after the separation cut, clean and oriented parallel to one another. The connecting edges 8a, 8b, which are located outside in the starting fiberboard, extend parallel to the outer edges, 12 but at the opposite ends of the parts 2a, 2b. The designation "connecting edges" means that the parts of panels 2a, 2b are connected to each other, by being pivotable or respectively foldable, by means of a connecting element 16 disposed in the area of these edges 8a , 8b. The connecting edges 8a, 8b have

  irregularities and are not yet prepared for the mounting of a connecting element 16.

  The two parts 2a, 2b are folded back, as indicated by an arrow P in FIG. 1 and shown in FIG. 2, by means of turning devices (not shown), with the visible faces 4 turned towards one another. . As turning devices, for example, turning stars, or also simple lever devices or scissor turning devices can be used. Turning devices can be simple because high precision is not necessary. After the reversal, the connecting edges 8a, 8b are arranged one on the other. The fiberboard parts 2a, 2b are then aligned so that the connecting edges lie on top of each other with flat surfaces. For alignment, simple stops, on which the outer edges 10, 12 are supported, are sufficient. The parts 2a, 2b aligned with flat surfaces are fixed by removable clamping devices, preferably pairs of clamping rollers5 14 (pressure direction: arrow F in FIG. 2), arranged respectively above and below the of them

  parts 2a, 2b. Springs, pressure cylinders or the like are also suitable. The clamping device can also be combined with a transport means for transporting the parts 2a, 2b, for example of the type of a pair of transport rollers with pressure rollers.

  The parts 2a, 2b thus fixed are then machined in the area of the connecting edges 8a, 8b in order to create a suitable surface and of adhesion for a connecting element 16. The machining is advantageously carried out by saws. or strawberries. In the simplest case, the connecting edges 8a, 8b are chamfered, as shown in Figure 3a, so that the parts 2a, 2b20 have an approximately wedge-shaped profile. If the connecting element 16 has in itself a certain thickness, so that it could protrude above the reverse 4 after assembly, the machining of the connecting edges 8a, 8b can also lead to a profile. stepped25 according to Figure 3b. Connection edges 8a, 8b of concave or convex shape can also be formed for

special use cases.

  After machining the connecting edges 8a, 8b, the connecting element 16 is mounted. The connecting element 16 is as shown in Figures 5 and 6, a synthetic adhesive to

  suitable fusion, preferably a polyurethane adhesive. A suitable adhesive is, for example, that known under the registered trademark JOWATHERM Reaktant (manufacturer: Lobers und35 Franck GmbH & CO KG, Detmold, Germany).

  The adhesive is applied by means of a nozzle (not shown) of an appropriate shape which guarantees that the adhesive is completely deposited on the machined connecting edge 8a, 8b and that a predefined profile is preserved for the connecting element 16 Examples of such predefined profiles are shown in FIGS. 5 and 6. The profiles5 are in this case chosen in such a way that they stabilize the parts of fiber panels 2a, 2b in the deployed state, thanks to the fact that they fill the free volume produced by the machining of the connecting edges 8a, 8b (see FIG. 6a). If necessary, the adhesive application device is placed immediately in front of an adhesive hardening device, for example a

  cooling installation or an ultraviolet device. It is guaranteed by this arrangement that, when a predefined profile must be preserved, the adhesive is then fixed directly after application, in the predefined form.

  FIG. 7 shows parts of panels 2a, 2b which have profiled connecting edges 8a, 8b. The connecting edges 8a, 8b include a step 18a, 18b and a slope 20a, 20b. The advantage of this profile is that the sticky fabric strip used here, despite its thickness, does not protrude above the backs 6a, 6b of the panel parts 2a, 2b after installation. This is particularly advantageous when stacking foldable fiberboard because completely stacked

planes are packed.

  During or after the machining of the connecting edges 8a, 8b, it is possible to machine other edges of the panel parts 2a, 2b, for example the outer edges, and / or to machine the reverse

of these parts of panels 2a, 2b.

  Another preferred embodiment of the method according to the invention provides that the outer edges 10, 12 of the fiberboard parts 2a, 2b serve as connecting edges, so that the edges created by the separation cut become outer edges of the foldable fiberboard 13. This procedure has the advantage that the absolutely parallel edges produced by the separation cut provide an appropriate stop for the foldable fiberboard, while the outer edges 10, 125 without this still require machining. If the outer edges 10, 12 are thus used as connecting edges, a work pass is eliminated by the machining of these connecting edges, since the rectification of the outer edges of the foldable fiberboard is avoided. Considering the extreme pressure on prices exerted on these products, we obtain

  this makes for a significant cost advantage.

  It is obvious that the arrangement described above of the means for machining the parts of fiber panels and the means for depositing the connecting element, as well as, if necessary, the means for hardening the connecting element, on the side of the transport path or respectively laterally to the panel results in a reduction in costs relative to the arrangement of these means centrally above the fiberboard. The devices mentioned are simpler to monitor and adjust and the correct deposition of the connecting element is simpler to execute and can be carried out immediately after application. If any unwanted anomalies are found, the corresponding devices can be set to

again without delay.

  In the process according to the state of the art, the time difference between the process and product checks, which takes place only after folding of the parts of the panels linked to each other, is much more large, as well as in correspondence also the proportion of rejects. There is also the risk that damage, which results from faulty handling of foldable fiberboards due to overloading of the connecting elements, may be regarded as a bad work of the aforementioned devices. It then triggers overcorrections which lead to an additional creation of scrap. It is therefore obvious that the process according to the invention is more economical, more

  simple and more reliable than the state of the art.

Claims (10)

  1. Method for manufacturing foldable fiber panels, which have at least one face (4) exposed to view, with at least two parts of fiber panels (2a, 2b) which are connected to each other, along a connecting edge (8a, 8b), by a connecting element (16), characterized by the following steps: - separation of a fiberboard into at least two parts of fiberboard (2a, 2b ), by means of a separation cut, - places one on the other of the two parts of fiberboard (2a, 2b), the faces (4) exposed to view being turned one towards the other, 15 - alignment with flat surfaces of the parts of fiber panels (2a, 2b) at least along the connecting edges (8a, 8b) on which the connecting element (16) will be fixed, - removable fixing of the two fiberboard parts (2a, 2b), - machining of the connecting edge (8a, 8b) on each of the fiberboard parts (2a, 2b),   - mounting, and if necessary hardening, of the connecting element (16).   2. Method according to claim 1, characterized in that the connecting element (16) is a   synthetic glue, in particular a polyurethane-based fusion glue.   3. Method according to claim 1, characterized in that the connecting element (16) is a   strip, if necessary coated with glue.   4. Method according to one of claims 1 to 3,   characterized in that the connecting edge (8a, 8b) is profiled during machining.   5. Method according to one of claims 1 to 3,   16 characterized in that the connecting edge (8a, 8b) is chamfered during machining.   6. Method according to one of claims 1 to 5,   characterized in that hard fiber panels or medium density fiber panels are machined.   7. Method according to one of claims 1 to 6, characterized in that there are fixed means of   fixing the aligned fiberboard parts (2a, 2b), means for machining the edge (Sa, 8b) on which the connecting element (16) will be arranged and means for depositing the element connection (16), and the parts of fiber panels (2a, 2b) to be bonded, 15 are presented continuously, in front of these means for machining the connection edges (8a, 8b) and for mounting the connection element (16 )   on the edges (8a, 8b) of the at least two parts of fiber panels (2a, 2b).   8. Method according to one of claims 1 to 6, characterized in that the means for machining the edges (8a,   8b) on which the connecting element (16) will be mounted and the means for mounting the connecting element (16) are guided in front of the fiberboard parts (2a, 2b) aligned and fixed to machine the edges of connection (Sa, 8b) and for mounting the connection element (16) on the edges (8a, 8b) of the at least two parts of fiber panels (2a, 2b).   9. Method according to one of claims 1 to 8, characterized in that the parts of fiberboard   (2a, 2b) are arranged with the faces exposed to view (4) one on the other so that the edges (8a, 8b) produced by the separation cut are the edges exterior (10, 12).   10. Method according to one of claims 1 to 9, characterized in that, during or after the machining of   connecting edges (8a, 8b) and the mounting of the connecting element (16), other edges (10, 12) of the fiberboard parts (2a, 2b) are machined and / or the surfaces are machined   fiberboard parts (2a, 2b).