DE2750848A1 - Veneered wooden panel rounded edge shaping method - involves deformable slotted curved batten inset in groove before bending - Google Patents

Abstract

In e.g. chipboard mfg., rounded corners on panel edges are produced with thin surface layer of pliant material. A groove (3) is worked into the main panel (1), without extending into the surface layer (2), with width matching the radius of curvature of the corner required. A batten, of solid but slightly deformable material, is made separately, as a corner inset with width matching the max. radius required, and this incorporates a number of deep lengthways slits (9). The corner inset is fixed with its underside on the base of the groove, and the panel unit, together with this inset, is then bent into the desired shape. Less precise dimensional accuracy is required for the corner inset pieces, with an elastic bending area and permissible tolerances, and no danger of veneer breaking or blistering.

Description

Method for producing rounded corners on plate-shaped

Bodies of the invention relates to a method of making rounded Corners of any shape and size on plate-shaped bodies that form a supporting base made of wood or similar rigid material and at least on one of them Side with a surface layer made of a thin and easily flexible material are provided.

The invention is particularly suitable for the production of counter lessons, such as furniture, cladding elements, etc. made of wood, in particular chipboard, board, Plywood, plywood and the like can be used, with the carrier material at its one side with veneer made of precious wood, a plastic layer or a laminate made of plywood and plastic or the like.

is coated.

With the usual production of rounded corners, for example with 900 rounding, two building panels are joined together at an angle, after which the The corner is rounded by planing or grinding the initially sharp corner. These method cannot be used for building panels that have a surface layer made of veneer, synthetic resin, veneer synthetic resin laminate or the like. are provided because in In such a case, at least the corner section is re-veneered after the rounding has been created must be, which increases the workload significantly.

Nan has previously tried to make rounded corners by Grooves were worked into the wooden plate to a certain depth, whereupon the "slat was bent inward against these grooves. One such method is true can be used in certain cases, but with many types of wood there is a risk that the wood panel breaks during bending and that the surface veneer or surface layer is clicked. To avoid this danger, one has to bend with humidification and heat is usually carried out in several stages, a process which is both time consuming and expensive. Certain relatively brittle materials, such as chipboard, board or the like. cannot be treated in this way, not even in connection with the heat and humidification treatment mentioned.

It has also been suggested to create rounded corners make that a relatively wide groove in the wood material down to the veneer layer is milled out and the groove exposed in the area of the veneer layer is bent will.

In order to get an even curve and the ones that are moved together when bending To keep edges of the wood panel separate, a solid wood corner piece is put in inlaid the corner and with the veneer layer and sometimes with the wooden panel glued. Such an insert must be extremely dimensionally accurate, as only one Corner insert that is not too large prevents the building board from bending at right angles or alternatively the tension on the veneer layer can be so great that it tears. If the corner insert is made too small, the veneer layer can become too small on the other hand, do not cling tightly to the corner insert and there can be joints and Bubbles appear.

Jer invention is based on the object with the last-mentioned Procedures to address related problems and propose a procedure with significantly lower demands on the dimensional accuracy of the corner inserts be made, the bending area is somewhat elastic and certain tolerances of the corner inserts are allowed without the risk of breaking the veneer layer or the formation of bubbles in the veneer.

The invention is explained in more detail below with reference to the drawing. They show: FIG. 1: a perspective partial illustration of one with a straight one Grooved building board and a corner insert before it is inserted into the Groove; Fig. 2: a cross-sectional view of a plate body after the formation of a rounded corner; 3: the corner section of this plate body on a larger scale; Fig. 4: an illustration of the difficulties with a previously proposed one Method; and FIG. 5: an illustration in the same way of the fundamentals of Method according to the invention.

The invention relates to a method for producing rounded corners Any shape and size of plate-shaped bodies that form a supporting base made of wood or similar rigid material and at least on one of them Side with a surface layer 2 made of a thin and easily flexible material The base can be made of fiber material or wood material, for example consist of solid wood, plywood, plywood, board, chipboard or similar, and the surface layer 2 can be a thin veneer layer made of fine wood, a synthetic resin layer, a laminate made of veneer and plastic or similar. Such panels are known and are widely used in the manufacture of furniture, interior decoration items, Denial elements or the like is used.

To make rounded corners in such a plate, a relatively wide groove 3 through the base and up to, but not into the surface layer milled. The width of the groove 3 should essentially match the external dimensions (radians) match the rounding to be produced. The transitions between the groove flanks on the base and the groove base, the exposed section 4 of the surface layer, are preferably provided with certain roundings 5, as below will be explained in more detail, have significance for the method according to the invention. In certain cases it can be useful to apply a thin layer of the pad to the to leave exposed section 4, especially with curves with large Radii; normally, however, the groove 3 is milled up to the surface layer 2.

To get an even curve and the exposed section A corner insert is used to support the surface layer evenly and stably 6 used made of wood, plastic or similar somewhat deformable material can exist. The corner insert 6 is formed from a strip 7 which is attached to the Lower edges with rounded corners 8 corresponding to the curves 5 at the transitions the base is provided and on the top a larger number of longitudinally extending Has slots 9.

The slots 9 extend to a bottom wall 10 and are separated by partitions 11 like a comb. Also the two outer slots on the outside delimiting side walls 12 merge into bottom wall 10, the latter s dimensioned is that it can be bent evenly without risk of breakage. Preferably are the outer walls 12 slightly wider than the partition walls 11, around the flanks of the groove 3 to give support and to facilitate handling of the corner insert. At its bottom can be the slotted bar with a layer 13 Fabric, synthetic resin, fiberglass or similar material are provided for their purpose it is to hold the bottom of the corner insert together / una the risk eliminate cracking; in addition, the layer 13 facilitates attachment of the corner insert in the groove 3.

The corner insert 6 is with its bottom by gluing, sneezing or in another suitable manner on the exposed portion 4 of the surface layer 2 attached, while its rounded corners 8 and its side walls 12 unattached stay. Then the plate body is bent towards the insert side until the desired curvature, for example the rectangular shape according to FIG. 2, is achieved is.

In this bending process, the slotted bar 7 is open at its Side pressed together, the walls 11, 12 being pressed together and possibly. come to one another to the plant. The number of slots and their width are determined according to the desired bending angle when bending. For a bend at an obtuse angle Relatively narrow slots are sufficient, but for one that encloses an acute angle In the bend, the slots should be relatively wide. Prevented during the bending process the underside of the corner insert or its bottom layer 13 is dented of the exposed portion 4 of the surface layer 2, the stress of the section 4 of the surface layer 2 is relatively small.

When bending, the rounded corner areas 8 and the outer walls 12 of the corner insert at the complementary transitions and flanks of the groove 3 slide along so that the corner insert in the change in shape as a result of Bending process inserts exactly into the groove. By this sliding movement of the corners 8 and Outer walls 12 in the groove 3 will also introduce excessive tensile forces in the exposed section 4 of the surface layer 2 prevented.

After bending the plate body into the intended shape, the plate body held in the usual way in the formed position.

As mentioned above, the method proposed earlier Corner insert pieces made of solid wood in the form shown in Fig. 4 are used. Such inserts are very difficult to manufacture because they are very precise Dimensional accuracy to groove 3 must have either excessive stress with the risk of breakage of the surface layer 2 or, conversely, the formation of waves or wrinkles in the exposed section 4 of the surface layer, associated with poor stability and adhesion between the two layers of the panel body in the corner area avoid. Furthermore, it is difficult to use the known corner insert precisely and to attach to the exposed surface layer as it is essentially must be freely inserted into the groove 3 and does not have to be to the exposed one before bending Section of the surface layer fits.

Figure 4 shows schematically the case that the corner insert is a little wider than the groove 3. Assuming that the ideal width of the insert corresponds to the line 14, the edges 15 of the excess material form oment points when bending the panel body around the corner piece. Hence the surface layer stretched around the piece 16 on each side of the corner insert / the side flanks the groove 3 can come to rest on the sides of the corner insert; such However, the system is a prerequisite for a good and stable corner construction. That The outer dimension 16 of the stretching of the material is from the distance to the center point 17 of the radius of curvature dependent and obviously much larger on the outer circumference of the curved section than the excess thickness 18 of the corner insert at the inner edge 15. A Misfit at the inner edge of the corner insert is therefore worsened with increasing distance from the center of curvature 17, so that known, massive corner inserts make high dimensional accuracy necessary.

In Fig. 5 is a corner insert in a corresponding manner shown according to the invention, and this has / relatively thin solid outer part 19 corresponding to the bottom wall 10 and a slotted and thus flexible inner part 20 on. It can be seen that the moment application point when bending the corner is now is relocated to a point 21 near the outer edge of the corner insert, more precisely said, on the borderline between the massive and resilient parts. This Moment application point 21 can, however, both because of the possibility of displacement of the rounded Corner 8 during the bending process as well as because of the change in shape of the corner insert can be viewed as flowing during the bending process, so that the new .experienced usually an undesirable stretching or stretching of the surface layer in the Area of the section 4 is not done even if the corner insert something should be too wide. Thanks to the flexibility of the inner part 20, the Corner with the same production of the corner insert either via a be bent at an obtuse or acute angle. As can be seen in Fig. 5, the weighs Moment application point 21 when bending fairly close to the outer circumference of the corner insert, so that the bend causes only slight stresses in the surface layer can.

In certain cases, especially if you have a very stable construction if desired, it may be useful to have the surface layer 2 multilayered with a inner carrier layer 2a and an outer veneer layer 2b.

Such an arrangement is particularly suitable for fragile veneers. The carrier layer can be a plastic layer, a volcanic fiber layer or any other suitable material.

Because of the design of the corner insert as an initially flat bar the corner insert can very easily at the desired location in the groove 3 of the Plate body are attached, and because of the slotted design of the corner insert the latter can easily be given a suitable rounding without damaging effects the surface layer 2 of the plate-shaped body can be deformed. Thanks to the slots 9, the corner insert is relatively easy to deform and this deformability is favored by the rounded corner sections 5 and 8 of the groove 3 and the strip 7, so that even small dimensional deviations of the corner insert have no harmful effects on the shape and stability of the object to be manufactured.

Claims (6)

Method for producing rounded corners of any desired Shape and size of plate-shaped bodies that support a wooden base or similar stiff material and at least on one side with provided with a surface layer made of a thin and easily flexible material are, d u r g e k e n n -z e i c h n e t, that in the supporting base (1) A groove (3) is machined deep into the plate-shaped body, however does not reach into the surface layer (2) and has a radius of curvature the width to be produced has a corresponding width that a corner insert (6) in the form of a bar with essentially the * -ößten radius of curvature of the one to be produced Corner corresponding width made of solid, limited deformable material separately is made, with a number of longitudinal, far in the material of the bar reaching into, bottom-bounded slots (9) formed is that the corner insert is attached to a bottom at the bottom of the groove and that finally the plate-shaped body together with the corner insert is bent into the desired shape. 2. The method according to claim 1, characterized in that the groove (3) through the supporting base (1) to the surface layer (2), but not is milled into this and that the corner insert (6) with the in the ut (3) exposed section (4) of the surface layer 2) is glued. 3. The method according to claim 1 or 2, characterized in that the slots (9) in the strip (7) forming the corner insert piece up to one Depth of more than half the thickness of the bar can be incorporated and the contiguous The bottom wall (10) is connected to the section exposed in the groove (3). 4. The method according to any one of claims 1 to 3, characterized in that that the transitions between the groove flanks and the groove base (4) are rounded and the remaining parts of the groove flanks essentially rectangular to the flat sides of the plate-shaped Body are shaped and that the corner insert with a corresponding cross-sectional shape will be produced. Method according to one of Claims 1 to 4, characterized in that that the corner insert (6) with a layer (13) of thin, easily deformable Material such as synthetic resin, fiberglass or the like. is occupied. 6. The method according to any one of claims 1 to 5, characterized in that that the number of slots (9) in the bar (7) and the width of each of these Slots is matched to the intended radius of curvature in such a way that at a large radius of curvature relatively few and / or narrow slots and with a small one Radius of curvature comparatively more and / or wider slots are provided.