DE19804787C2 - Process for making foldable fiberboard - Google Patents

Description

The invention relates to a method for producing foldable fiberboard, which has at least one Show visible side. Fiberboard all include lignocellulosic Fibreboard, for example hardboard or medium density fibreboard (MDF). Such panels are used, for example, as rear wall panels.

For a long time, the rear wall of a cabinet was built up from individual fibreboards by separate Fasteners were connected and fixed together. To handle To minimize individual parts, however, has been looking for ways for some time, separable To produce cabinet back panels that can be installed without tools.

Known methods for the continuous manufacture of interconnected Plate parts are, for example, in German Patents 838 361 (Dichmann) and 44 18 274 (BHF). Both methods have in common that they are in continuous Manufacturing processes can be integrated. This is an unconditional requirement for this To be able to offer bulk items without unnecessary manipulation at minimal prices.

DE-PS 838 361 proposes a plate from which the to each other connecting fiberboard parts are to be produced, first provided with grooves, the grooves are then covered by an adhesive tape. Finally the Bottom of the groove milled away from the other side and the individual, together connecting plate parts are arranged on the adhesive tape. This procedure is for the Manufacture of furniture rear panels unsuitable because it cannot be used for panels with at least a visible side, because both surfaces when performing this procedure the plate can be processed.

In DE-PS 44 18 274 a method is described which is used to produce foldable Back walls for furniture, i.e. for fiberboard with at least one visible side is suitable. This method, which takes up the steps of DE-PS 838 361, is also used First a groove is milled, then an adhesive is applied and finally through Editing the visible side of the bottom of the groove severed. The connected by the glue Panel parts are then folded so that the visible sides face each other. This The procedure is very complex to carry out. Machining the fiberboard on the Visible side without damaging the groove with the adhesive is hardly possible without it Damage occurs on the visible side of the fiberboard or on the adhesive. The folding of the Fiberboard parts after applying the adhesive and milling the second groove often already leads damage to the adhesive.  

It is therefore an object of the invention to provide a simple and inexpensive method for to propose continuous manufacture of foldable fiberboard.

This object is achieved by a method with the features of claim 1. The starting product for the production of foldable fiberboard is at least one side coated or otherwise rewarded by a continuous Processed fiberboard. The one coated with lacquer or decorative paper, for example In the following, the page is called the view side. The - mostly uncoated - second side of the Fiberboard is referred to below as the screen side.

The starting fiberboard from which the foldable fiberboard is to be made is first broken down into at least two fiberboard parts by a separating cut. The cut can be done from the visible side as well as from the sieve side. The two fiberboard Parts are then turned with the help of appropriate turning devices, for example with the help a turning star or a lever arrangement, placed on top of each other. The Visible sides of the fiberboard parts turned towards each other.

This step of completely separating the single output fiberboard and the subsequent turning of the fiberboard parts is new and related to that Further processing of fiberboard into furniture parts is extremely unusual. The so far pursued approaches have always avoided such a step because the turning and Aligning the plate parts to the specialist as cumbersome, complex and space-consuming Intermediate step appears. So far, it has always been preferred to process as far as possible in one plane continuously on continuous or chained together Let conveyor systems run through, and the plate parts only after applying the adhesive or fold tape. Any interruption of the continuous funding or even the manipulation of plate parts was considered as a measure that the performance of the Production plant.

However, it has proven to be a great advantage in experiments that the continuous Manufacturing of foldable fiberboard in the sequence of the steps of claim 1. On Separation cut with which the original fiberboard is completely broken down into two fiberboard parts can be carried out with an easy to adjust saw. It is not an expensive one Setting a precise depth of cut is required, as is the case when making a groove necessary is. If the cut is made from the visible side, the Visible side at the cutting edge largely avoided because the saw on the screen side of the Fiberboard emerges and consequently any tears in the area due to the cut resulting edge lie on the sieve side. This process has a particular advantage  also that straight edges are generated that do not require any further processing. These edges, hereinafter referred to as outer edges, lie on the stop after turning on. The edges on the outside of the fibreboard, followed by connecting edges called can now be processed according to the inventive method so that not only the adhesive or tape can be applied, but that the finished Plate parts have exactly the specified dimensions.

The turning of the plate parts can be done with the simplest tools, which are plate parts freely movable and easy to manipulate. In contrast, the plates must be folded again the method described in DE-PS 44 18 274 with great care, that is be carried out according to precisely adjusted machines to ensure that the Plates can not be moved against each other, so that the glue or tape is damaged.

The fiberboard parts are then aligned so that they are along one Connection edge can be connected to each other. Aligning the plate parts happens with the help of simple stops on which the at least two plate parts by means of Conveyors are aligned. As already explained, the plate parts with the outer edges created by the separating cut are aligned with the stops. The at the Output fiberboard outer edges, the connecting edges, are through this Alignment accessible to the other processing devices. The flush Fiberboard parts are then releasably fixed so that they can be used for the following Processing steps remain in a defined position to each other. It is preferred that Fix fibreboard parts after alignment using a clamping device. Suitable Clamping devices are, for example, spring-mounted pairs of rollers that exert pressure on the Exercise superimposed fiberboard parts.

The fiberboard parts are then profiled along the connecting edge. in the in the simplest case, the connecting edge is chamfered from the sieve side to the visible side, However, to create a good adhesive surface for the glue or the adhesive tape is also possible to profile the connecting edge, for example when the adhesive or the The adhesive tape should be flush with the level of the screen surface. Advantage of this The procedure is that these work steps can be constantly monitored optically, and that Adjustments and changes in the setting can be made simply because of the required processing devices arranged laterally and thus easily accessible are. In the prior art methods described above, the Fiberboard across the entire width of the conveyor or across the conveyor Machined in the middle of the conveyor line and there are milling and application devices for glue and the like on both the visible surface side and the screen surface side  required. In contrast, in the method according to the invention, all are Machining devices attached to the side of the conveyor line, because it only has to the connecting edges of the fiberboard parts are profiled, as the outer edges already are completely processed. A particular advantage of the method according to the invention is seen in the fact that the successive processing of parallel edges of individual, correlated fiberboard parts the specified dimensions and angles can be observed particularly precisely and with minimal effort.

If necessary, the connecting edge is still after the profiling for the application of the Glue or the tape prepared, for example by applying a seal or an adhesive component.

Finally, the glue or tape is applied. In the simplest case, a Glue applied, preferably a synthetic adhesive based on polyurethane. Such adhesives are offered as hot melt adhesives, for example a PUR adhesive with a Viscosity of 22,500 ± 7,500 mPas at 120 ° C and a processing temperature of 120 ° C up to 140 ° C. But it is also easily possible that a possibly provided with adhesive Tape, e.g. B. a fabric or foil tape is used.

Depending on which glue is used, the fiberboard parts are now so long fixed until the adhesive has hardened. If necessary, pass through the fiberboard parts at least in the area of the connecting edge provided with the adhesive, a device for Curing of the adhesive.

After the adhesive or tape has been applied and, if necessary, hardened, the Fixing device released and the foldable fiberboard is now immediate, without further Manipulations must be made ready for dispatch. It proves to be advantageous here that the visible surface from the beginning of processing before damage or Contamination is protected. Dripping glue, dust or damage from on the Saws or milling arranged on the visible side are in the method according to the invention locked out.

Depending on how the production systems are designed, the devices for Carrying out the process either stationary or movable, so that the fiberboard parts can be processed either continuously or in a resting position (cyclically). With regard on the higher performance in the continuous production by means of conveyor lines Devices for carrying out the method, the clamping devices, the saws or Milling to edit the connecting edge and the devices for applying the Adhesive or the adhesive tape preferably arranged stationary and the plate parts are on  moved past the fixtures. But it can also prove to be useful the devices for performing the method and the fiberboard parts at the Perform the procedure in the same or opposite direction.

Exemplary embodiments of the invention are described in detail below with reference to figures described. Show it

Fig. 1 is a perspective view of two fiberboard parts after separation

Fig. 2 is a perspective view of two superimposed and aligned fiberboard parts

Fig. 3a shows a perspective view of two profiled at a connecting edge fiberboard parts

FIG. 3b is a perspective view of two at a connection edge profiled fiberboard parts

Fig. 4 is a perspective view of two fiberboard parts foldably connected by means of an adhesive

Fig. 5 is a side view of two fiberboard parts connected by a synthetic adhesive in the folded state

Fig. 6 is a side view of two fiberboard parts connected by a synthetic adhesive in the folded state

FIG. 6a is a side view of the two connected by a synthetic adhesive fiberboard parts according to Figure 6 in folded-out condition.

Fig. 7 is a side view of two fiberboard parts connected by an adhesive tape

The continuous production of foldable fiberboard, which in particular as Furniture back panels are used, generally immediately follows the Production of an endless band of fiberboard. The one-sided coated Endless fiberboard is at least as wide as the maximum width of the back of the furniture and has a thickness between 1.5 mm and 8 mm. The continuous fiberboard is made using Cutting saws cut to the length required for the back of the furniture. The on the The appropriate length of shortened fiberboard may need to be cut to the appropriate width become. To - especially for furniture that is offered as a kit in flat packages - To achieve convenient transport dimensions, the fiberboard is often only half the width of the Have furniture. Therefore, the fiberboard must be foldable. The procedure To produce such foldable fiberboard, the simple process must be simple and inexpensive manufacture of large quantities.  

Fig. 1 shows two hardboard parts 2 a, 2 b with a material thickness of about 3.5 mm, which are coated on the visible side 4 with decorative paper. The screen side 6 is unprocessed and uncoated. The parts 2 a, 2 b have after the separation of opposed outer edges 10, 12. The outer edges 10 , 12 are clean after the separating cut and 5 aligned parallel to each other. Parallel to the outer edges 10 , 12 , but at the opposite ends of the parts 2 a, 2 b, the connecting edges 8 a, 8 b lying on the outside in the starting fiberboard run. The term "connecting edges" indicates that the plate parts 2 a, 2 b are connected to one another in a pivotable or foldable manner by means of an adhesive or an adhesive tape 16 arranged in the region of these edges 8 a, 8 b. The connecting edges 8 a, 8 b have irregularities and are not yet prepared for the application of an adhesive or adhesive tape 16 .

The two parts 2 a, 2 b are, as indicated by the arrow P in FIG. 1 and shown in FIG. 2, folded with the visible sides 4 to one another by means of suitable, not shown turning devices. As turning devices, for example, turning stars or simple lever arrangements or scissor turner can be used. The turning devices can be simple because no great precision is required.

After turning, the connecting edges 8 a, 8 b are arranged one above the other. The fiberboard parts 2 a, 2 b are then aligned so that the connecting edges are flush with one another. Simple stops against which the outer edges 10 , 12 rest are sufficient for alignment. The flush-aligned parts 2 a, 2 b are fixed by releasable clamping devices, preferably pairs of clamping rollers 14 (pressure direction: arrow F in FIG. 2), which are each arranged above and below the two parts 2 a, 2 b. Springs, pressure rollers or the like are also suitable. The clamping device may also be a means of transport for conveying the parts 2 a, 2 be combined b, z. B. in the manner of a pair of conveyor belts with pressure rollers.

The parts 2 a, 2 b thus fixed are now profiled in the area of the connecting edges 8 a, 8 b in order to create a suitable support and adhesive surface for an adhesive or an adhesive tape 16 . Profiling is expediently carried out with milling or sawing. In the simplest case, the connecting edges 8 a, 8 b, as shown in Fig. 3a, beveled, so that the parts 2 a, 2 b have an approximately wedge-shaped profile. If the adhesive or the adhesive tape 16 itself has a certain material thickness so that it could protrude beyond the sieve side 4 after attachment, the profiling of the connecting edges 8 a, 8 b can also lead to a stepped profile according to FIG. 3 b. Concave or convex connecting edges 8 a, 8 b can also be produced for special applications.

After the connecting edges 8 a, 8 b are profiled, the adhesive or the adhesive tape 16 is applied. The adhesive 16 , as shown in FIGS. 4 to 6, is a synthetic, meltable adhesive, preferably a polyurethane adhesive. A suitable adhesive is, for example, Jowatherm® Reactant (manufacturer: Lobers and Frank GmbH & Co. KG, Detmold).

The adhesive is applied by means of a suitably shaped nozzle (not shown here), the shape of which ensures that the adhesive is completely applied to the profiled connecting edge 8 a, 8 b, and that a predetermined profile for the adhesive 16 is maintained. Examples of such predetermined profile, Figs. 4 to 6. The profiles are chosen so that they stabilize the fiberboard parts 2 a, 2 b in the unfolded state, by the by the profiling of the joint edge 8 a, 8 b incurred Fill in the space (see Fig. 6a). The application device for the adhesive is optionally arranged directly in front of a device for curing the glue, for example a cooling system or a UV system. This measure ensures that just when a predetermined profile is to be maintained, the adhesive is fixed in the predetermined shape immediately after application.

Fig. 7 shows plate parts 2 a, 2 b, which have profiled connecting edges 8 a, 8 b. The connecting edges 8 a, 8 b comprise a shoulder 18 a, 18 b and a slope 20 a, 20 b. The advantage of this profile is that, despite the material thickness, the adhesive tape made of fabric used here does not protrude beyond the screen sides 6 a, 6 b of the plate parts 2 a, 2 b. This is particularly advantageous when stacking the foldable fiberboard, because completely flat stacks are packed.

Another especially preferred embodiment of the process of the invention provides that the outer edges 10, 12 of the fiber plate parts 2 a, 2 b serve as connecting edges, so that the edge produced by the severing cut to joining edges of the foldable fiber plate. This procedure has the advantage that the absolutely parallel edges created by the separating cut result in a suitable closure of the foldable fiberboard, while the outer edges still require processing anyway. Thus, if the outer edges 10 , 12 are used as connecting edges, the profiling of these connecting edges eliminates an operation since the outer edges of the foldable fiberboard need not be straightened. In view of the extreme cost pressure on these products, this creates a significant cost advantage.

It is obvious that the arrangement of the means for processing described above the fiberboard parts and the means for applying the adhesive or the adhesive tape and If necessary, to harden the adhesive on the side of the conveyor line or on the side of the plate compared to the arrangement of these means in the middle of the fiberboard also for  Cost reduction helps. The devices mentioned are easier to monitor and adjust and the correct application of the glue or tape is easier too accomplish and can be carried out immediately after application. Should it be here too unwanted deviations can occur, the corresponding devices without Time delay can be reset.

In processes according to the prior art, the time interval between the process and product control, which takes place only when the interconnected plate parts are folded, much larger, and accordingly the share of committee. That exists about this Risk of damage from incorrect manipulation of foldable fiberboard under Overuse of the connecting elements arise as incorrect work of the the aforementioned devices are considered. This will cause over-corrections triggered, which cause further production of rejects. It is obvious that that The inventive method is cheaper, easier and more reliable than the state of the Technology.

Claims (9)

1. A method for producing foldable fiberboard, which have at least one visible side ( 4 ), with at least two fiberboard parts ( 2 a, 2 b), at least in sections along a connecting edge ( 8 a, 8 b) by an adhesive or an adhesive tape ( 16 ) are connected with the steps

• 1. separating a fiberboard by a cut in at least two fiberboard parts ( 2 a, 2 b),
• 2. stacking of the two fiberboard parts ( 2 a, 2 b), the visible sides ( 4 ) being turned towards one another,
• 3. flush alignment of the fiberboard parts ( 2 a, 2 b) at least in sections along the connecting edges ( 8 a, 8 b), on which the adhesive or the adhesive tape ( 16 ) is arranged,
• 4. releasable fixing of the two fiberboard parts ( 2 a, 2 b),
• 5. Profiling the connecting edge ( 8 a, 8 b) on each of the fiberboard parts ( 2 a, 2 b),
• 6. Attach and, if necessary, harden the adhesive or the adhesive tape ( 16 ).

2. The method according to claim 1, characterized in that the adhesive ( 16 ) is a synthetic adhesive, in particular a hot melt adhesive based on polyurethane. 3. The method according to claim 1, characterized in that the adhesive tape ( 16 ) is an adhesive-coated fabric or film tape. 4. The method according to at least one of claims 1 to 3, characterized in that the connecting edge ( 8 a, 8 b) is chamfered during profiling. 5. The method according to at least one of claims 1 to 4, characterized in that Hardboard or medium density fibreboard can be profiled.   6. The method according to at least one of claims 1 to 5, characterized in that fixed means for fixing the aligned fiberboard parts ( 2 a, 2 b), means for profiling the edge ( 8 a, 8 b) on which the adhesive or the adhesive tape ( 16 ) is arranged, and means for applying the adhesive or the adhesive tape ( 16 ) are provided, and that the fiberboard parts ( 2 a, 2 b) to be connected are continuously guided past these means in order to connect the connecting edges ( 8 a, 8 b) and to attach the adhesive or tape ( 16 ) to the edges ( 8 a, 8 b) of the at least two fiberboard parts ( 2 a, 2 b). 7. The method according to at least one of claims 1 to S. characterized in that the means for profiling the edges ( 8 a, 8 b) on which the adhesive or the adhesive tape ( 16 ) is arranged and the means for applying the adhesive or the adhesive tape (16) on the aligned and fixed fiberboard parts (2 a, 2 b) are passed to the connection edges (8 a, 8 b) to profile and to the adhesive or the adhesive tape (16) at the edges (8 a, 8 b) to attach the at least two fiberboard parts ( 2 a, 2 b). 8. The method according to at least one of the preceding claims, characterized in that the fiberboard parts ( 2 a, 2 b) are placed one on the other in such a way with the visible sides ( 4 ) that the edges created by the separating cut, the outer edges ( 10 , 12th ) are. 9. The method according to at least one of the preceding claims, characterized in that during or after profiling the connecting edges ( 8 a, 8 b) and the application of the adhesive or the adhesive tape ( 16 ) other edges ( 10 , 12 ) of the fiberboard parts ( 2 a, 2 b) are processed, or that the surfaces of the fiberboard parts ( 2 a, 2 b) are processed.