EP1237688A2

EP1237688A2 - Device for generating a chip and a device for profiling a tree trunk

Info

Publication number: EP1237688A2
Application number: EP00985092A
Authority: EP
Inventors: Hans Dietz; Jürgen EDELMANN
Original assignee: Dietz Hans Prof Dr
Current assignee: Dietz Hans Prof Dr
Priority date: 1999-12-15
Filing date: 2000-11-25
Publication date: 2002-09-11
Anticipated expiration: 2020-11-25
Also published as: DE19960319C1; US20030005976A1; DE50009510D1; EP1237688B1; US6719022B2; CA2391804A1; WO2001043927A2; ATE288817T1; WO2001043927A3; CA2391804C; ES2236016T3

Abstract

The invention relates to a device for generating an essentially wedge-shaped chip (10'), in particular during profiling of tree trunks. The chip (10') is cut from the wood using a cutting tool (44) which can be rotated about a first axis (46). Said chip is cut out in such a way that it has a first, concave surface (12) and a second, convex surface (14) that define between them the chip (10'). The first axis (46) runs horizontally. The inventive device is provided with a circular saw blade (70) which can be rotated about a second, vertical axis (72). Before cutting the chip from the wood, the saw blade removes wood from a region where the surfaces (12, 14) converge in an imaginary tip (16).

Description

Device for producing a wood chip and device for profiling a tree trunk

The invention relates to a device for producing a substantially wedge-shaped woodchip, in which the woodchip is machined from the wood by means of a chipping tool that can be rotated about a first axis in such a way that it has a first, concave surface and a second, convex surface, which is between them limit the wood chips. The invention also relates to a device for profiling a tree trunk, with a chipping tool rotatable about a first axis for chipping longitudinal corners out of the tree trunk, with means for sawing off side boards from the tree trunk, one narrow side of which is formed by one edge surface of the corner, and with a circular saw blade to make a saw cut along the other edge surface before removing the corners.

In woodworking technology, it is generally known to cut wood in whole or in part by means of so-called chipping tools. The chipper tools are usually rotating tools with chipper knives on their circumference. The chipper tools are usually arranged fixed in space, and the wood to be chipped or chipped is guided along the chipper head in the axial direction of the wood.

Because of these conditions, the wood chips produced have a wing-like shape with an essentially wedge-shaped cross section. The wood chips are delimited on their two large surfaces by a concave or convex side, these sides leading from a thick end of the wood chip to a thin end or, in the cross-sectional representation, of a tip in which the two surfaces run tangentially into one another.

Wood chips are a valuable raw material in various branches of industry. This includes the pulp industry, the paper industry, but also the manufacturers of wood-based materials and so-called composite components, ie Panels, boards and beams made by gluing wood chips.

These processing companies accept wood chips according to a certain classification. Wood chips of medium size are particularly preferred because wood chips that are too large are difficult to process and that wood chips that are too small or too thin lead to losses or to no viable structures, particularly in the production of pulp, paper, wood-based materials and composite components.

The classification of the wood chips delivered is decisive for the price that a processing company is willing to pay for these wood chips. Accordingly, there is a considerable desire in the woodworking industry to produce only those woodchips that achieve the highest prices within the classification of the processing industry.

If wood chips are produced by means of a rotating chipping tool in the manner described in more detail above, they have the thinly tapering end along their wedge-shaped cross section. This thin end is a disadvantage for the further processing of the wood chips, because this thin end either dissolves in the pulp or leads to areas that are not very stable in the production of composite components. In practice, wood chips are produced either when wood is completely cut or when wood is partly cut out.

A partial removal of wood takes place e.g. when profiling tree trunks. This means the all-round processing of initially raw tree trunks in order to give them a cross-sectional shape (profile), in which the profiled tree trunk can be easily broken down into boards and beams by subsequent sawing. A corresponding method and a corresponding device are e.g. described in DE 29 28 949 A.

In these known methods and devices, the tree trunks are processed during profiling by means of so-called corner cutters, which mill corners out of the tree trunk in the axial direction, so that the tree trunk, which was flattened on all sides before or after, is given a profile in which so-called side boards can be sawn off.

A corresponding method and a corresponding device are described in DE 37 02 980 C2. In the known method, a first, for example horizontal saw cut of predetermined depth is first made from one side of a tree trunk, in which case the axis of rotation of the saw blade runs vertically. After making the saw cut or (using a combined tool head) at the same time, a section of the wood above the saw cut is removed, with the axis of rotation of the chipping tool, or in the case of a combined tool head, the common axis of rotation, vertical runs. The removed area does not reach as far horizontally into the tree trunk as the first saw cut is deep. The remaining area above the horizontal saw cut is then machined out in a further work step, specifically by means of a cutting tool, the axis of rotation of which runs horizontally in the example mentioned. Afterwards or simultaneously with the chipping process, a second, vertical saw cut is made, the bottom of the gap created in this case being at the center where the first, horizontal saw cut ends in the wood. As a result, a whole area is worked out of the tree trunk that is corner-like, but is basically stepped at the corner. It is important here that at no time does one of the two cutting tools reach into an area that was previously sawn out. In this known method, as has already been described, only so-called "comma chips" are generated.

EP 0 770 461 A2 discloses a method and a plant for dividing tree trunks into smaller wood products. In this method, a tree trunk is profiled by first sawing the corners completely using circular saw blades whose axes are inclined at 90 ° to one another. When sawing out, strips are created that are removed from the actual profiling system and completely cut in a separate chipper.

A method for processing tree trunks is known from EP 0 775 558 AI. In this method, a longitudinal cut is first made through the tree trunk using a band saw running in the vertical direction, alternatively also Circular saws are proposed. The saw cut is in any case placed in a vertical plane so that it separates a side board from the tree trunk. The saw blade is followed by a separating element in the sawn gap, with which the side board, which is still materially connected to the tree trunk, is kept at a distance from the remaining main goods. The separating element in turn is followed by a combined trimming tool, which can be rotated about a vertical axis and, in the manner already described, consists of a chipper and a circular saw blade connected to it. With this tool, the corner area above the narrow side of the side board to be produced is machined and at the same time the narrow side of the side board is machined with a high-quality surface using the circular saw blade. The cutting knife and the circular saw blade have the same radius in the cutting tool. The flight circle runs tangentially to the broad side of the separated side board, in other words, the saw teeth and the chipper blades do not run into the gap created by the leading band saw. Even if, in this known method, the flight circle of the span knife would extend into the gap, this would be irrelevant in connection with the present invention, because band saws are known to produce only extremely narrow sawing joints, which are typically a maximum of 3 mm wide. This would only affect the outermost tips of the chips. However, this would only result in an economically insignificant change in the shape of the chips. With this known method, the "comma chips" already mentioned are generated in principle.

In all of the above-mentioned methods and devices, conventional wood chips with a tapered end are produced on the one hand and sawdust on the other hand. DE 43 37 682 Cl discloses a method and a device for cutting a tree trunk.

In accordance with the known method, side boards are sawn from a tree trunk flattened at the side, which are still provided with forest edges at their edges. These side boards are bent out of the sawing plane as long as they are still materially connected to the tree trunk at the leading end and then run essentially parallel to the tree trunk at a distance. In this spaced-apart position, the side boards are machined on the narrow sides by means of a trimmer and thus trimmed. The cutting edges of the edger chipper run through the wood in the area of the forest edges at a radial pressure angle of approx. 45. The side boards thus run past the edger chipper almost in the area of the axis of rotation. This is possible because, as mentioned, the side boards are currently spaced from the main goods. The purpose of this measure is to produce so-called "equal-thickness chips" when trimming the previously bent side board, ie chips which, in contrast to the so-called "comma chips", have an essentially constant thickness parallel to the wood fiber. These "equal-thickness chips" are approximately parallelogram-shaped in cross-section, the corner angle being approximately 45 ° (or 135 °) because the plane of engagement of the chipper on the wood, as mentioned, is below approximately 45 ° to the direction of movement of the side boards.

The known method and the known device thus have the advantage of producing chips which are more favorable for subsequent processing in the cellulose industry are, but this advantage must be bought with considerable additional effort because the side boards after sawing out of the sawing plane and must be trimmed there at a considerable distance from the main goods. This is not possible with all types of wood, at least not without damaging the side boards when bending in the fiber.

In contrast, the invention is based on the object of developing a wood chip and method and devices of the type mentioned at the outset or of specifying the uses mentioned in order to avoid the disadvantages mentioned above. In particular, wood chips should be produced in an economically optimal manner, the shape of which corresponds as closely as possible to those classes of wood chips that are most highly paid for by the processing industry

In a device for producing a wood chip of the type mentioned in the introduction, the object is achieved in that the first axis runs horizontally and in that a circular saw blade rotatable about a second, vertical axis is provided in order to remove the wood in the area prior to the removal , in which the surfaces converge in an imaginary tip.

In a device for profiling a tree trunk of the type mentioned, the object is achieved in that the circular saw blade is rotatable about a vertical axis, and that the cutting tool with its radius of the circle extends into the gap created by the saw cut, such that it is empty therein running. The object underlying the invention is completely achieved in this way.

In contrast to conventional, wedge-shaped chips with a thinly tapering end or a thinly tapering tip, the invention provides for this thinly tapering end to be removed, so that only the thicker end of the chips remains.

Such a shortened wood chip has a much higher economic value and can therefore be processed in a much better way. The operator of a sawmill system can therefore expect a much higher economic yield during the recycling of the chips with such shaped chips.

The fact that in the devices according to the invention the axis of rotation of the circular saw blade runs vertically and the axis of rotation of the cutting tool horizontally has the advantage that smaller drives can be used, so that there are economic and constructive advantages.

In contrast to the device according to EP 775 558 AI, the circular saw blade is not used according to the invention for separating a side board, but rather only for creating a gap of finite depth.

The circular saw blade is preferably formed with a thickness of more than 5 to 6 mm. The circular saw blade is preferably followed by a riving knife which is arranged between the circular saw blade and the chipping tool. This measure opens up the possibility of preparing the wood to be chipped or chipped in one and the same work step by means of a cut, in particular a saw cut, in such a way that the shortened wood chips mentioned arise immediately when the rotating chipper tool is subsequently engaged, since the area has already been removed beforehand, in which the tapered ends or tips would have been produced.

Further advantages result from the description and the attached drawing.

It goes without saying that the features mentioned above and those yet to be explained below can be used not only in the combination indicated in each case, but also in other combinations or on their own without departing from the scope of the present invention.

Exemplary embodiments of the invention are shown in the drawing and are explained in more detail in the following description. Show it:

Figure 1 is a sectional view through a wood chip, as it is produced with conventional chipping tools.

FIG. 2 shows an illustration, similar to FIG. 1, but for a wood chip produced in accordance with the invention;

3 shows a schematic, radial cross-sectional illustration of a tree trunk to explain a profiling process; Fig. 4 and 5 are extremely schematic views of a device for producing wood chips of a conventional type;

FIG. 6 shows an illustration, similar to FIG. 5, but on an enlarged scale and with a different axis arrangement, illustrating an embodiment of an apparatus according to the invention for producing wood chips according to the invention when profiling tree trunks; and

7A to 7D four diagrams to explain the operation of the device according to FIG. 6

In FIG. 1, 10 denotes a woodchip of a conventional type. The woodchip 10 has two sides or surfaces 12, 14 which are perpendicular to the plane of the drawing and form the essential surface of the woodchip 10. The left surface 12 in FIG. 1 is concave, and the right surface 14 is convex. The surfaces 12 and 14 converge tangentially at the bottom in FIG. 1 in a tip 16 or edge. A preferably flat end face 18 can be seen at the opposite end of the chips 10. Overall, the wood chips 10 thus have a thick end 20 and a thin end 22.

1 give problems in further processing in the pulp industry or in the industry for the production of composite components, in particular beams or boards, because the thinner end 22 has hardly its own stability and also dissolves during further processing in a liquid medium or is destroyed under greater mechanical stress, so that undefined fragments remain.

The economic value of the chips 10 can therefore be increased significantly if the thinner end 22 is removed.

This takes place in the embodiment of the invention shown in FIG. 2 in that a cut is made through the wood chips 10 along a parting plane 24, so that the thinner end 22 is removed.

The position of the parting plane 24 within the woodchip 10 "can be determined in different ways. Here, economic considerations are of primary importance, i.e. the question in which remaining shape of the woodchips 10 'offers the best economic yield.

If one imagines a center line 26 between the surfaces 12 and 14, then for example the center line section 26a within the remaining wood chip 10 'with a length l _x and the imaginary center line section 26b outside the remaining wood chip 10', namely up to the tip 16, Define with a length of 1 ₂ , the total length of the original wood chip being 10 l _x + 1 ₂ . An optimal position of the parting plane 24 is, for example, when 1 _{2 is} between 40% and 100% of 1 ₁ . Another possible definition is in the transition from the convex surface 14 to one Boundary surface 28 along the parting plane 24 to define the thickness d of the remaining wood chips 10 'with, for example, between 2 and 10 mm.

In the arrangement shown in FIG. 2, the interface 28 forms an acute angle α with the center line 26, which e.g. can be between 15 ° and 50 °.

In preferred exemplary embodiments of the invention, the flat end face 18 is produced by machining or sawing and the interface 28 by sawing in the axial direction. They are therefore flat and run parallel to each other.

In FIG. 3, the essentially circular radial section through a tree trunk is indicated by dash-dotted lines. The so-called rinds 32 are located on the side of the tree trunk 30, i.e. Surface sections affected by forest edges.

So-called corners 34 are provided at four circumferential positions of the tree trunk 10, each offset by 90 ° to one another. When the rinds 32 (usually by machining) and the corners 34 (usually by milling or chipping) are removed, a so-called model remains, from which side boards 36 and then further boards and / or a so-called main item can subsequently be sawn.

In Fig. 3, 38 and 40 denote the two edge surfaces of the axially continuous corners 34.

4 shows the area of a corner 34 of the tree trunk 30 again on a greatly enlarged scale Corners 34, a corner mill 44, generally speaking a rotating chipping tool, is used. The corner milling cutter 44 can be rotated about a vertical axis 46 in the direction of an arrow 48. The axis 46 runs perpendicular to the longitudinal axis of the horizontally aligned tree trunk 30.

The corner milling cutter 44 is composed in a manner known per se from two tools, namely a chipper 50 and a saw blade 52 or a corresponding number of planing knives.

When the corner milling cutter 44 (arrow 48) rotates, the knives of the chipper 50 dip into the corner 34 in the region of the first edge surface 38, while at the same time the second edge surface 40 of the corner 34 is treated by the saw blade 52 or the planing knives.

In this way, the second edge surface 40 receives a relatively high (sawn) surface quality, while the first edge surface 38 receives a wavy surface due to the rotary knife rotating with a rotary movement.

FIG. 5 shows a top view of the arrangement according to FIG. 4. The arrow 54 indicates the rotary movement of the corner milling cutter 44 rotating around the vertical axis 48. Its radius is denoted by r.

An arrow 56 indicates the direction of advance of the tree trunk 30 relative to the corner milling cutter 44 which is mounted in a fixed position (or vice versa). The plan view according to FIG. 5 also shows a flattened area 58 on the tree trunk 30, where the corresponding rind 32 has previously been removed by flattening it sideways has been. The flattened area 58 is separated by an axially extending transition line 60 from the remaining forest-edged area 62, in which the corner 34 is to be worked out by means of the corner mill 44.

5, the wood chips 10 according to FIG. 1 are produced in this conventional manner.

In contrast, in the device according to the invention shown in FIG. 6, the orientation of the axis 46 'of the corner milling cutter 44 is first changed. According to the invention, this runs horizontally. Furthermore, a circular saw blade 70, which rotates about a vertical axis 72, is arranged in front of the revolving corner milling cutter 44, as indicated by an arrow 74. The axis 72 runs perpendicular to the longitudinal axis of the tree trunk 30, which in turn is aligned horizontally. The circular saw blade 70 thus saws a horizontal gap 76 of finite depth d (FIG. 7D) along the transition line 60. The circular saw blade 70 typically has a thickness of more than 5 mm, preferably 6 mm and more, so that the gap 76 is correspondingly wide, at least considerably wider than in the case of a band saw. Depending on the individual case, the circular saw blade 70 can also be provided with particularly wide teeth.

A circular wedge 78 can follow the circular saw blade 70 and ends in the axial direction where the engagement area of the corner milling cutter 44 begins.

The arrangement is such that the gap 76 lies where the thin end 22 of the chips would lie in the conventional procedure (FIG. 5). Since the wood already there is already present in this area through the circular saw blade 70 has been removed, the cutter blades of the cutter 50 of the corner milling cutter 44 run empty, as does the saw blade 52 or the planing blades.

As a result, the wood chips 10 ′ are produced without the thinner end 22, ie they only consist of the thicker end 20.

It goes without saying that the circular saw blade 70 is only to be understood as an example in this respect, and that other cutting tools can of course also be used, e.g. the width of the gap 76 should be larger.

The procedure shown in FIG. 6 also has the advantage that the first edge surface 38 'is also designed with a saw-quality surface from the outset.

FIGS. 7A to 7D again illustrate the sequence of the processing steps in the device according to FIG. 6 in four pictures.

7A shows the moment at which the circular saw blade 70 (vertical axis of rotation 72) rotating in a horizontal plane dips laterally into the tree trunk 30a.

7B shows that the circular saw blade 70 has created the horizontal gap 76 of finite width d in the tree trunk 30b.

7C shows the corner milling cutter 44, which is now engaged on the tree trunk 30c, and which rotates about the horizontal axis 46 '. rotates. The corner mill 44 cuts out the chips 10 'in a shape according to FIG. 6.

7D finally shows the final state of the tree trunk 30d with milled or sawn corner 34 ', both edge surfaces 38' and 40 'being of high surface quality.

Claims

claims

1. Device for producing an essentially wedge-shaped wood chip (10; 10 '), in which the wood chip (10; 10') is machined from the wood by means of a chipping tool (44 - 52) which can be rotated about a first axis (46), that it has a first, concave surface (12) and a second, convex surface (14) which delimit the wood chips (10; 10 ') between them, characterized in that the first axis (46) runs horizontally, and that a Circular saw blade (70) rotatable about a second, vertical axis (72) is provided in order to remove the wood before chipping in the area in which the surfaces (12, 14) converge in an imaginary tip (16).

2. Device according to claim 1, characterized in that the circular saw blade (70) in the wood creates a gap (76) of finite depth (d).

3. Device according to claim 1 or 2, characterized in that the circular saw blade (70) is at least 5 mm, preferably at least 6 mm thick.

4. The device according to one or more of claims 1 to 3, characterized in that between the circular saw blade (70) and cutting tool (44 to 52) with the circular saw blade (70) aligned riving knife (78) is provided.

5. Device for profiling a tree trunk (30), with a cutting tool rotatable about a first axis (46) (44 to 52) for removing longitudinal corners (39) from the tree trunk (30), with means for sawing off side boards (36) from the tree trunk (30), one narrow side of which is from one edge surface (40) of the corner (34) is formed, and with a circular saw blade (70) for guiding a saw cut along the other edge surface (38) before the removal of the corners (34), characterized in that the circular saw blade (70) is rotatable about a vertical axis (72), and that the cutting tool (44 to 52) extends with its flight circle radius (r) into the gap (76) created by the saw cut, such that it runs empty therein.

6. The device according to claim 5, characterized in that the circular saw blade (70) in the wood creates a gap (76) of finite depth (d).

7. The device according to claim 5 or 6, characterized in that the circular saw blade (70) is at least 5 mm, preferably at least 6 mm thick.

8. The device according to one or more of claims 5 to 7, characterized in that between the circular saw blade (70) and cutting tool (44 to 52) with the circular saw blade (70) aligned riving knife (78) is provided.