NO338716B1 - Wood elements and method of processing them - Google Patents

Description

Wooden element and method for processing this

The present invention relates to a wooden element comprising at least one outer surface, at least one edge surface and at least one outer corner, as well as a method for processing this.

Background

When dividing or splitting wooden logs, many different types of wooden element can be obtained, partly with regard to dimensions and partly with regard to properties, depending on which part of the cross-section of the log they are taken from.

A round log must be split in its raw state to avoid cracking in the wood when the log dries. However, the disadvantage of wooden elements sawn from raw wood is that they shrink and warp, i.e. deform, when the log later dries. For wood with high requirements for flatness and dimensional accuracy, which is almost always the case, it is therefore required that it be planed to the correct dimensions and flatness after drying.

For wood that is to be used as cladding wood or panels on e.g. walls and ceilings, however, a planed surface is a disadvantage, since in case of subsequent painting, the paint has difficulty adhering to the smooth and planed surface. The danger is simply that the paint layer becomes too thin. This increases the risk that the paint will peel off afterwards, with a subsequent need for repainting. Especially with external wooden panels, the weather protection can also be too poor, as the wood is attacked by rot.

When sourcing cladding panels intended for painting, panelboards have previously been sourced through dry sawing of the center yield, i.e. in normal cases, the two rectangular blocks of wood sawn out of the center of each log. After drying these wooden blocks, they are planed on each side to create a correct measurement and to correct for the shrinkage and deformation that occurs during drying. After planing, the wooden block can be split sawn into panel boards of the desired thickness. Each such panel table thus receives at least a sawn surface with a rough surface structure which is suitable for use as an outer surface of a panel table, in that its paint absorbing ability becomes good. However, the edge surfaces of these panel tables still have a smooth and planed surface and similarly sharp outer corners, on which paint has difficulty adhering.

Utilizing the proceeds from the center for the procurement of panel tables is also a form of waste of resources, as these could instead be used for the procurement of larger wooden elements with e.g. bearing function.

At least four side tables from the area outside the center yield usually come out of each log. These side tables mainly have so-called horizontal annual rings, i.e. annual rings that extend along the plane of the table, and also usually have denser annual rings than the center yield, which is why shrinkage and consequent deformation become significant during drying. Planing, i.e. planing, of the side tables is therefore necessary before they can be used for any purpose where measurement accuracy and flatness are important. At the same time, planing, as previously mentioned, produces smooth surfaces, which makes them unsuitable as panel tables intended for painting. This is a major disadvantage as side tables of e.g. spruce, has greater resistance to rot than wood that comes from the center yield, their usually denser annual rings, making the wood harder and the number of twigs is often less than in the center yield.

With all types of wooden elements intended for painting, the outer corners also pose a particular problem. Sharp corners formed between two sawn surfaces, e.g. 90° to each other, in principle have no paint-holding ability at all, which constitutes a way in for rot in the wood, and is also a disadvantage when handling the wood manually, as the risk of damage increases. If the outer corners are rounded, as usually happens with planed wood, a smooth surface is formed on the other side, which also does not have a good ability to absorb paint.

The invention

The invention relates to a method for producing a wooden element, which removes the above-mentioned problems and by which at least one outer corner is formed with good paint-absorbing and paint-holding capacity. At least this purpose is achieved by means of a method in accordance with patent claim 1.

The invention also applies to a wooden element, which is made with at least one outer corner that has good paint-absorbing and paint-holding capacity. At least this purpose is achieved by means of a wooden element in accordance with patent claim 7.

The invention is thus based on the insight that a good paint-absorbing ability of a wooden element's outer corner can be achieved by rounding the corner and providing it with riffles, which are preferably so shallow that the riffling becomes invisible to the naked eye when using normal cover paint measurement, e.g. e.g. base paint layer and two finished paint layers.

In accordance with an embodiment according to the invention, a wooden surface is also provided with ridges in order to achieve a good paint-absorbing ability of the outer surface. Also these riffles are preferably so shallow that they become invisible to the naked eye using normal tire paint measurement. The wooden surface can consist of an edge surface and/or an outer surface.

Within the scope of the invention, the rifles can have different shapes and sizes. The number of rifles can

vary depending on the size of the corner or surface to be fluted. Common to all the designs, however, is that the riffles are made along the direction of the wood fibers so that one does not needlessly cut into the fibers, which will entail an increased risk of moisture penetration. In the preferred embodiment is

the riffles are wave-shaped, where the ridges formed have a rounded top in cross-section, and the grooves formed have a bottom rounded in cross-section. As a rule, it is preferable that the tops of the hills are slightly rounded or flat, in order to be properly covered with paint, while pointed or saw-toothed hills are less suitable. However, it should be possible to carry out the knurling in the form of semi-circular ridges in cross-section, which are placed next to each other so that they meet at an acute angle to form the grooves. Also a trapezoidal rifling, i.e. ridges and grooves formed with mutually perpendicular and planar limiting surfaces, will be possible. The dimensions of the rifles can also be varied as required. In a preferred design, the center distance between two adjacent ridges is less than 2 mm, preferably less than 1 mm, and preferably around 0.75 mm. The depth of the grooves, i.e. the distance between the tops of the ridges to the bottoms of the grooves, is in the preferred design less than 1 mm, preferably less than 0.5 mm, and preferably less than 0.25 mm.

Furthermore, the knurling can be produced in different ways. In a preferred embodiment, the knurling is done by

using a cutter, which has a rotating cutting tool with a rifled profiled egg. This results in a puncture-free surface that facilitates manual handling of the wood and also makes the wood visually appealing. With the help of a cutter, it is also possible to produce the wooden element with high measurement accuracy and flatness, i.e. that the tops of the hills are placed in essentially the same plane. The

however, it should also be possible to create the rifling in another way, e.g. through rolling using fluted rollers or scoring the surface using a suitable, preferably rotary scoring tool. The latter method would, however, give a significantly more prickly and less appealing surface.

It is within the scope of the invention that the rounded surface of an outer corner of a wooden element or any arbitrary surface can be provided with a knurling to improve paintability. Thus, e.g. panel boards made in the usual way from a center dividend, are provided with riffles. The surface also does not have to be flat, but can be e.g. the curved surface of a round post.

In a preferred embodiment, however, the embodiment in accordance with the invention is used to produce panel tables from the side yield or the side tables of a log. As previously mentioned, the side yield of, for example, spruce has better resistance to rot than the center yield. Similar conditions may also apply to certain other types of wood, but it is within the scope of the invention that side tables can be taken out, in accordance with the procedure described below, from any arbitrary type of wood. A major advantage of the method is that it leads to a better utilization of resources by increasing the usability of the edge tables.

After sawing such a side table, it is dried in a generally known way, and then becomes deformed as a result of the shrinkage, so that the core side, i.e. the side that was facing the center of the log, becomes convex, while the splint side, i.e. the side which faces the curved surface of the stick becomes concave. This table is then finished in such a way that the core side is fluted and plane machined with the aid of a flute forming cutting tool in such a way that the tops of the hills of the flutes are placed in substantially the same plane. In the same way, the side edges are fluted and machined flat and the outer corners are rounded, similarly with flutes on the roundings.

The side edge processing and the corner rounding can conveniently be done with one and the same tool. The splint side of the tables can be planed and possibly provided with riffles in a similar way, but in accordance with a preferred embodiment, the table's splint side is not planed, but instead the already existing concave surface is further reinforced with the help of a concave cutting tool. However, not over the entire surface, but only in a central area, while approx. 0.5 - 2 cm of each edge area is left unprocessed. This side of the table will serve as the back side of a cladding panel and therefore also does not need any knurling as it will not be painted. As a result of the natural shrinkage, the outer edge areas will also have a slightly concave acute angle in relation to the side surfaces, which means that the installation and sealing against the substrate, e.g. the outside of another panel table will be very good, which is advantageous in that it i.a. prevents the penetration of moisture. Through such concave processing of a generally concave surface, the advantage is achieved that different panel tables are shaped the same, even if they should have different concavities after drying. At the same time, such a method saves material as no material is removed from the table's thickest cross-section, i.e. inside the edge areas, and the tables thus do not need to be removed with any excess size when sawing.

An outer corner or a wooden surface made in accordance with the present invention thus provides a surface with very good painting properties, both for brush painting and spray painting. The term paint, as used here, is to be interpreted broadly and does not necessarily have to be a cover paint, but can also be a transparent varnish, oil or an impregnating agent. With such a surface treatment, the grain of the wood will eventually not be covered by the paint, but will form an appealing surface structure on the wood. The knurling also means that the penetration capacity for oil and impregnating agent increases. For varnish, just as for tire paint, the knurling results in an increased attachment surface, which contributes to increased attachment and reduced risk of flaking. A wooden element in accordance with the invention is particularly suitable for use as a panel table on walls and ceilings, especially as a cover-painted outer wall panel. Wooden elements with ribbed surfaces will, however, have many areas of application, such as e.g. for furniture production or as a floor on e.g. docks and patios where the knurling will advantageously help to reduce the risk of slippage.

Example

The invention will now be described in more detail with reference to the attached drawings, where:

Fig. 1 shows a schematic end view of a log, which shows the possible main principle for splitting the raw log,

Fig. 2 shows an end view of a side table, which shows the deformation of the table after drying,

Fig. 3 shows a schematic end view of the side table during plane machining of its upper side using a rifled profile cutting tool, Fig. 4 shows an end view of the side table during machining of its underside using a convex cutting tool, Fig. 5 shows an end view of the side table below side edge processing and corner rounding using two opposing fluted profiled cutting tools, Fig. 6 shows a detail enlargement of a corner area of the side table, which shows the fluted profile of the outer surfaces, Fig. 7 shows a further enlarged detail of a wooden surface, which shows the special design of the ribbing, and Fig. 8 shows a schematic cross-section through a wall panel, made up of side tables produced in accordance with the invention.

First, reference is made to Fig. 1, which shows a possible main principle for splitting a log 1 in its raw state. According to this principle, a center yield is taken from each stick, where the cross-sectional dimensions of the center yield roughly correspond to the largest square that can be taken out within a circle that corresponds to the diameter of the narrow end of the stick. The center yield is in turn divided into two parts 2, through a saw cut through the log's core. If the core is still in the wooden element during drying, the formation of cracks increases drastically. In the area outside the center yield, there are usually opportunities to remove at least one side table 3 on each side of the center yield, which have a smaller width than the center yield.

The sawing in accordance with Fig. 1 takes place while the log is still raw and after sawing all surfaces are flat and all angles are perpendicular. During drying, however, the wooden elements shrink and deform. The deformation of the side tables 3 is particularly large. Partly as a result of the orientation of the annual rings in the table, partly through the fact that the annual ring width is often smaller further out in the cross-section of a log. In Fig. 2, the deformation of the edge table is shown on an exaggerated scale after drying it. As can be seen, the edge board's core side 4, i.e. the side that faced towards the center of the log, will bend outwards, i.e. become convex, while the splint side 5, i.e. the side that faced the curved surface of the log, bends inwards , i.e. becomes concave. The corner angles between a side edge 6 and the core side 4 or the splint side 5 are also changed so that they are usually no longer perpendicular.

The deformation of the side tables during drying means that these must be post-processed in order to be used for purposes where flatness and measurement accuracy are important. Fig. 3 shows a, in accordance with the invention, first processing step of the side table's core side or front side 4, i.e. the side which is intended to be facing outwards in a cladding panel, and which as a rule is intended to be surface treated, e.g. . is measured with cover paint. The core side 4 is plane machined using a schematically shown rotating cutting tool 7. In order to avoid a completely flat and smooth surface where the paint has difficulty penetrating and sticking, the cutting tool's edge is fluted to give a fluted wooden surface, which will be described in more detail detailed later. The fact that the wooden surface is planar should therefore only be interpreted as meaning that the tops of the ridges of the rifles will end up in the same plane.

As previously mentioned, the side table's spline side 5 is concave after drying. In accordance with a preferred embodiment of the invention, this concavity is maintained and reinforced as can be seen in Fig. 4.1 in this processing step a rotary cutting tool 8 is used, which has a convex egg edge which is used to reinforce the concave shape of the splinter side by processing a central area of this surface. In contrast, an edge area 9 at each side edge is left untreated. Through such a design, the side table comes against one surface when installed, e.g. underlying panel boards, to lie close to the substrate and thus prevent the ingress of moisture. The sealing is aided by the fact that the untreated edge areas 9 usually have an angle in relation to the side edges 6, which is less than 90° as a result of the deformation during drying. In a preferred form, the concave processing takes place to a depth of 1 - 3 mm, preferably to around 2 mm, from the plane of the outer edge areas.

Next, reference is made to Fig. 5 which shows the processing, in accordance with the invention, of the side edges 6 of the side tables and the outer corners 10 between the side edges 6 and the core side 4. This is done with the help of two opposing and rotating cutting tools 11, each of which has an egg edge with a curved part 12 to, at the same time as the processing of the side edges, also round the outer corners 10. The radius of the curved egg part 12 can suitably be approx. 1.5 mm. Like the cutting tool 7, the edges of the cutting tool 11 are rifled, also in the curved egg part 12, to give wooden surfaces a good paint-absorbing ability.

Fig. 6 shows a detailed enlargement of an outer corner area in Fig. 5, from which the knurling in the wooden surfaces 4, 6 and the outer corner 10 can be seen, and in Fig. 7 the cross-sectional shape of the knurling is illustrated more closely through a further enlargement of a wooden surface. As can be seen from the figures, the rifling in the preferred embodiment is sinusoidal with the same radius of curvature at the tops of the ridges 13 of the riffles and the bottoms of the grooves 14 of the riffles. In the preferred embodiment, the center distance a between two adjacent riffles is less than 2 mm, preferably less than 1 mm, and preferably around approx. 0.75 mm, while the depth b between the peaks 13 of the ridges and the bottoms 14 of the tracks is less than 1 mm, preferably less than 0.5 mm, and preferably less than approx. 0.25 mm.

In Fig. 8, a possible application of the wooden element in accordance with the invention is shown as a panel table in a locking panel. With such a panel, a number of bottom boards 15 are attached to a base, e.g. a supporting stem, spaced apart. Then the space between adjacent bottom boards is covered by locking boards 16. When using panel boards of the previously described type, all surfaces facing outwards will show a knurling with good paint-absorbing ability and the connection between bottom boards 15 and locking boards 16 becomes very tight as a result of the panel boards concave design.

It should be appreciated that the previously described processing steps in accordance with Figs. 3 - 5 can conveniently be carried out essentially simultaneously and in one and the same machine.

Instead of using sideboards for the production of panelboards in the previously described manner, it will of course also be possible to saw panelboards out of the center parts 2 after drying them. The fronts of the panel tables thus get a sawn surface with good paint-absorbing ability, as previously described. Such panel tables will thus only need a processing of the side edges for measurement and angle adjustment, and a rounding of the outer corners, as well as simultaneous knurling of the side edges and outer corners for an improved paint-absorbing ability.

The described and preferred embodiment is only exemplified and within the scope of the invention any number of limiting surfaces can be provided with riffles. Designing the back sides of the panel tables with a concave shape is only an example of a possible design and this side can thus be unworked, planed or fluted according to the desired purpose, in accordance with the invention.

Claims (11)

1. Method for producing a wooden element comprising at least one outer surface, at least one edge surface and at least one outer corner which is rounded, characterized in that the at least one outer corner (10) is provided with at least one rifle comprising parallel ridges (13) and grooves (14) in the grain direction of the wood to improve the surface's ability to absorb paint. 2. Method in accordance with patent claim 1, characterized in that at least one edge surface is provided with riffles. 3. Method in accordance with one of the preceding patent claims, characterized in that at least one outer surface is provided with riffles. 4. Method according to one of the preceding patent claims, characterized in that the knurling is carried out to a depth (b) at the bottoms of the grooves (14) in relation to the tops of the ridges (13), which is less than 0.5 mm, preferably less than 0 .25 mm. 5. Method in accordance with one of the preceding patent claims, characterized in that the rifles are made so that they are not visible to the naked eye after painting with cover paint. 6. Method in accordance with one of the preceding patent claims, characterized by the steps: - sawing said wooden element in raw state, - drying the wooden element, where the same achieves a deformation in such a way that a core side (4) thereof becomes convex curved while a splinter side (5) is concavely curved, - supply the core side with riffles, and - reinforce the splinter side's concave curvature through a material-removing and concave machining of a central area of the splinter side. 7. Wooden element which exhibits at least one outer surface, at least one edge surface and at least one outer corner which is rounded, characterized in that the at least one outer corner (10) is provided with at least one rifle comprising parallel ridges (13) and grooves (14) in the fiber direction of the wooden element for to improve the wood's ability to absorb paint. 8. Wooden element in accordance with patent claim 7, characterized in that at least one edge surface is provided with riffles. 9. Wooden element in accordance with one of the preceding patent claims 7-8, characterized in that at least one outer surface is provided with grooves. 10. Timber element in accordance with one of the preceding patent claims 7-9, characterized in that the grooves have a depth (b) measured from the bottoms of the grooves (14) to the tops of the ridges (13), which is less than 0.5 mm, preferably less than 0.25 mm. 11. Wooden element in accordance with one of the preceding patent claims 7-10, characterized in that the wooden element comprises a core side (4) and a spline side (5), where the core side (4) is provided with grooves while the spline side (5) is concavely curved inwards through a material-removing machining of a central area to reinforce a natural concave inward curvature of the splint side (5) that occurs after drying the wooden element.