DE4337682C1 - Method and device for cutting a tree trunk - Google Patents

Abstract

A method and device are used for processing treetrunks (50) into wood products. The device comprises a circular saw (40) which has a spatially fixed deflecting element (44) parallel to a circular saw blade (41). The deflecting element (44) extends into the engagement region of teeth (42) of the circular saw blade (41). As side boards (side cuts) (51) are cut off, the deflecting element diverts these out of the plane of the teeth (42) from a main stock (52) of the treetrunk (50) directly after the passing of the teeth (42). The device further comprises first means for removing a wane (53) of the treetrunk (50), as well as second means for trimming the side boards (51) to predetermined lengths. The first means are constructed as edging-chipper assembly (60 to 63) and are arranged, in the conveying direction (54) of the treetrunk (50), directly downstream of the circular sawblade (40) but upstream of the second means. <IMAGE>

Description

The invention relates to a method for cutting a tree tribe in wood products, using a circular saw Side boards separated from a main item of the tree trunk the side boards immediately after passing the teeth of the circular saw by means of a fixed deflector bent from the plane of the teeth and subsequently in vorbe be cut to a certain length, furthermore measures to Removing a forest edge of the tree trunk, such that side boards are trimmed on both sides.  

The invention further relates to a device for disassembling of a log in wood products, with a circular saw, the a fixed deflector element parallel to a circular saw blade has, which extends into the engagement area of teeth of the Circular saw blade stretches and when detaching side boards the side boards of a main item of the tree trunk after passing the teeth turns out of the plane of the teeth, the device further comprising first means for removing a Forest edge of the tree trunk and second means for cutting off the Includes side boards to a predetermined length.

A method and an apparatus of the above Kind are known from WO 88/02683.

In the known method and the known device an otherwise conventional circular saw with a fixed, provided disc-shaped deflector that runs parallel to the Circular saw blade is arranged and in the edge area up to extends the engagement area of the teeth. The repellent element is slightly conical. If the circular saw z. B. a Separates the side board from a main item of a tree trunk, runs the separated side board on the conical, fixed Deflector element and is thus bent from the parting plane. This has the advantage that the separated side board is immediate after passing the teeth of the circular saw blade out of engagement comes with the rotating circular saw blade, so that the emergence of frictional heat is avoided.

In the known method and the known device no special measures affected the tree trunk or the side board from a forest edge, d. H. Bark remains on the edge  free the side board. The known method and the known device namely go from an already pretreated ten, namely from a profiled tree trunk.

A profiled tree trunk means one that subject to the already in previous processing steps delt is that of the originally raw tree trunk entire bark removed and a profile already in cross-section has been produced in which only side boards are separated must be or a decomposition of the tree trunk into other Wooden products (boards, planks, squared timber and the like) must take place.

Methods and devices for profiling tree trunks are known, for example from DE-PS 32 44 393, the DE-PS 29 28 949 and DE-PS 29 18 622.

In the method or device known from DE-PS 29 28 949 the initially raw tree trunk is flattened on all sides, see above that a cross-sectional shape of almost square shape ent stands, but in the area of the corners of the square curves with remains of bark, the so-called forest edges, still present are. In subsequent corner milling stations, these are included Corners with forest edges are now milled out so that a cross sectional shape emerges, with the shape of an ouadrate milled square corners. The corners can also be milled in several stages. Through subsequent separating cuts can now the laterally protruding rectangular profiles as pages boards are separated. These side boards are then with cut to length in standard lengths. This can ent neither happen while the side boards are not yet complete separated from the main goods, so still with this material connected, but it is also possible to use the side boards  initially over the entire length of the tree trunk from the main goods cut off and then cut to length in separate operations.

It is also well known, an initially raw one Just flatten the trunk sideways and then, so without separating any profiling, side boards, which then but are still provided with the forest edges on their sides. These separately handled side boards can then be used so-called trimming machiners are performed to both to separate the edges of the forest. The trimming machine units can be designed as circular saws with which the Sawed off the forest edge and then cut it, but there are also known tools with which the forest edges already at Severing.

In a method and a device of the aforementioned Type that already has a profiled, i.e. H. out at the corners Milling a tree trunk can, however, occur in practice Set problems if the corner cutters are not clean to the Circular saws are positioned after milling the corners detach the side boards. This is especially true then when the tree trunk during the machining process between the corner milling station and the circular saw again handled, for example promoted over long distances or is even rotated. Then it can happen that the kerf the circular saw its reference position to the two surfaces of the milled corner loses and either side boards with wrong ones Dimensions or with collar-like projections become.

Another disadvantage when profiling tree trunks Corner milling cutter is that the corner milling cutter with its rotating Immerse the peripheral surface tangentially into the wood of the tree trunk  and just support yourself on the tree trunk. this leads to for the formation of chips that thickened at one end and on other end are rejuvenated and therefore in the technical language be referred to as "comma chips". However, such chips are for customers of such chips, namely cellulose industry, undesirable because for further processing of the Chips in cellulose manufacturing fractions with constant Length and thickness are desired.

GB-PS 1 086 450 describes a method and a device known for processing tree trunks. After that, the Tree trunks are first attached on both sides using the first band saws flattens by a circular cross section on both sides cut-shaped, perfect on the circular arc-shaped surface part provided with a forest edge is separated. The one on this Tree trunk flattened in this way is then rotated by 90 ° and again flattened on both sides by means of a second band saw unit. The parts separated in this way become further band saws and circular saws to produce boards without forest edges. These boards without forest edges are then sorted direction using circular saws to a predetermined length lengthened.

The invention is therefore based on the object of a method and a device of the type mentioned in that regard further that the disadvantages mentioned above avoided become. In particular, dimensionally accurate and form-fitting pages should boards are generated, the resulting chips for a subsequent cellulose production should be suitable.

According to the method of the type mentioned, this task solved according to the invention in that the side boards in untrimmed condition separated and immediately after turning, but before trimming, fed to a trimming machine become.  

According to the device mentioned above, the task solved according to the invention in that the first means as Trimming machine unit designed and in the conveying direction the tree trunk immediately downstream of the circular saw blade, but are arranged upstream of the second means.

The object on which the invention is based is achieved in this way completely solved.

According to the invention, namely contrary to conventional Profiling process the step of trimming the side boards  again after the step of detaching the side boards relocated. However, in order to do so, an assignment between the circular saw and the trimming tool, in other words a high dimension and to ensure dimensional accuracy, the side boards trimmed in a state where it is still materially with the Tree trunk are connected. This is immediately after passing the circular saw the case. You make the fact take advantage of using a particular circular saw that is not only separates the side boards from the main goods, but these turns at the same time out of the parting plane. Then you have the side boards immediately behind the circular saw of the main goods available and can be done there with the now required space for trimming tools the untrimmed Trim the side board. As a result of the material unity between In this way, the side board and main goods are extremely and shape retention possible because of a rigid mechanical Connection between the side board in the area of the circular saw and the leading section of the side board in the area of the trimming tool.

In a preferred development of the invention is as Trimming cutter unit is a rotating trimming cutter used, the diameter of which is such that the sides boards approximately diametrically, namely below approx. 45 ° on handle angle to be moved past the trimmer.

This measure has the advantage that the level of engagement of Machiners on the wood at about 45 ° to the direction of movement Side boards lies. That thus acted upon in the radial direction Wood of the side board is broken up into chips in this way, whose thickness is constant parallel to the wood fiber and whose frontal cutting surface is chamfered at about 45 °. These In technical terms, chips are referred to as "constant thickness chips"  and are gladly accepted by the cellulose industry because they are suitable for the production of cellulose and paper. The procedure according to the invention, namely the side board trimming at a distance from the main goods has thus opposite the known profiling process the systematic advantage, that the chips can be produced in a more favorable form.

This applies in particular if, according to further training the invention, the side boards in the engagement area of the edging chippers are supported by means of an abutment.

This measure has the advantage that the chip production works particularly well with chips of equal thickness.

Further advantages result from the description of the appended drawing.

It is understood that the above and the following standing features to be explained not only in each specified combination, but also in other combinations or can be used alone, without the scope of to leave the present invention.

An embodiment of the invention is in the drawing shown and is described in more detail in the following description explained. Show it:

Fig. 1 is an unprocessed tree trunk in radial section;

FIG. 2 shows the tree trunk according to FIG. 1 according to a first processing step in a conventional profiling process;

. Fig. 3 is the tree of Figure 2 in accordance with a further nachfol constricting processing step;

FIG. 4 shows the tree trunk according to FIG. 3 according to a further processing step, namely the cutting off of a side board;

FIG. 5 shows a representation similar to FIG. 3, but to illustrate a possible method error;

FIG. 6 shows a representation similar to FIG. 4, to illustrate the defective wood products resulting from the process error;

Fig. 7 is a representation similar to Figure 3 to explain the chip production in a conventional Profilierver.

FIG. 8 shows a top view of the arrangement according to FIG. 7;

FIG. 9 shows a side view of a conventional trimmer chip arrangement to illustrate the circumstances prevailing there during chip production; FIG.

FIG. 10 is a plan view of an embodiment of a device according to the invention;

Fig. 11 is a sectional view taken along line XI-XI of Fig. 10.

Fig. 1 shows a radial section of a tree trunk 10 , which in the simplified representation consists of trunk wood 11 and a bark 12 surrounding the outside. Longitudinal planes on the tree trunk 10 are indicated by 13 , along which chipper tools can be guided in order to flatten the tree trunk 10 on all sides.

The result of the flattening is shown in Fig. 2. It can be seen that the tree trunk 10 now has an approximately square cross-sectional shape, which is determined on the sides by the planes 13. Only in the area of the corners are so-called forest edges 14 remaining as remains of the bark 12 . Axially extending corners are indicated by 15 in FIG. 2, which can subsequently be attached by means of so-called corner cutters in order to remove the forest edges 14 .

The result of this corner milling is shown in FIG. 3, where the corners 15 with their boundary surfaces can be clearly seen in the left half. 16 3 is shown in Fig. Indicates that a subsequent saw cut can be attached, wherein the thickness of the kerf is designated by d.

Fig. 4 shows the result of the saw cut sixteenth The originally still one-piece, profiled tree trunk has now been divided into a so-called main article 18 and a side board 17 . A side board can also be separated there by corresponding steps on the right-hand side of the tree trunk in FIG. 4, and the same applies to the top and bottom of the tree trunk, for which purpose the tree trunk is expediently rotated by 90 ° so that the same units can be used, who have previously performed the processing steps illustrated in FIGS . 2 to 4.

In Fig. 5 it is now illustrated that the profiling and cutting of tree trunks explained above can lead to certain errors. If, instead, the corner milling cutters are adjusted with a certain offset instead of in their desired position, which is designated by x in FIG. 5, then not a corner 15 according to FIG. 3 but rather a corner 15 'according to FIG. 5 is generated, the vertical surface of which is in the representation of Fig. 5 x offset by the amount to the left.

FIG. 6 shows the sequence when the saw cut 16 is subsequently made in the desired position of the saw blade. Because of the offset x of the corner 15 'is now namely a side board 17 ', on the right side approaches 19 remain. It is obvious that a side board 17 'thus produced is not for sale, but rather must be subjected to further post-processing, which leads to corresponding costs.

From the above it follows that when profiling and subsequent dismantling of tree trunks, an exact assignment of the tool positions must be guaranteed in successive machining steps, in connection with the promotion of the tree trunks between the various machining positions. The problems shown with reference to FIGS. 5 and 6 arise to a greater extent, the thinner the kerf, the less precise the positioning of the tools and the greater the distances between the processing positions and thus the travel paths of the tree trunk. In the process of tree trunks, changes in the position of the tree trunk can also result in assignment errors which lead to the consequences illustrated in FIGS. 5 and 6.

Another aspect of conventional profiling methods is shown in FIGS. 7 and 8.

FIG. 7 shows, in a representation that corresponds to the machining step according to FIGS . 2 and 3, a corner milling cutter 25 rotatable about an axis 24 . The axis 24 is perpendicular to the conveying direction of the tree trunk 10 , which is indicated in FIG. 8 by an arrow 26 . The corner milling cutter 24 rotates in a direction which is indicated by an arrow 27 in FIGS . 7 and 8.

The corner milling cutter 25 essentially produces the corner 15 with its end face, as can be clearly seen from the illustration in FIG. 8. The corner milling cutter 25 plunges essentially tangentially into the wood of the tree trunk 10 . It supports itself against the tree trunk 10 itself. Because of this a grip conditions of the corner milling cutter 25 on the tree trunk 10 , chips 28 are formed in the engagement area, which are thickened at the left end in FIG. 8 and tapered at the right end in FIG. 8. This is because the corner milling cutter 25 tangentially engages exactly at the right in Fig. 8 the end of the chip 28 into the wood of the tree trunk 10 and to the left in Fig. 8 at the end of a finite, but small angle. The mean pressure angle is designated by α in FIG. 8. It is exaggeratedly large there and in practice is in the range of a few degrees.

In this way, chips 28 are formed in the form of so-called "comma chips" which are thick at one end and thin at the other end.

The chips that occur when cutting wood are used as raw material used for the cellulose industry and by this in large  Extensively decreased. It is for the production of cellulose However, it is important to have the wood chips of uniform thickness and to have fiber parallel structure available so that it can can be dismantled evenly for further processing. For chips of irregular shape with different thickness this is not the case because the thinner areas tend to be there Fine goods result than the thicker areas. The so-called "Comma chips" are therefore problematic in further processing tables and are less popular with the cellulose industry assumed, in any case at lower purchase prices.

In comparison to this, FIG. 9 shows a situation such as that which arises, for example, in the case of a conventional trimming machine, with which a board is trimmed, for example.

In this situation, a board 30 is trimmed by means of a trimmer 31 , the trimmer 31 rotating about an axis 32 , as indicated by an arrow 33 . Another arrow 34 shows the advance of the board 30 relative to the trimmer 31 . 35 denotes an abutment on which the board 30 rests in the vicinity of the engagement area of the trimmer chip 31 .

Since the trimming chipper 31 has a very large diameter, the arrangement can be made such that the board 30 passes the trimming chipper 31 approximately at a 45 ° pressure angle. This is the angle between the direction of engagement of the trimmer 31 (arrow 33 ) and the direction of advance of the board 30 (arrow 34 ), which is practically 45 °, as indicated by an angle β in FIG. 9.

The resulting chips 36 have a constant thickness over their entire length parallel to the wood fiber and an end face with an inclination of approximately 45 °. They are therefore referred to in technical terms as "constant thickness chips". These chips are economically more valuable than "comma chips" as explained above.

In the game of the invention shown in FIGS. 10 and 11, this knowledge is now used.

In the device according to the invention, a circular saw 40 is provided with a circular saw blade 41 which is provided with teeth 42 on its circumference. A drive shaft 43 ensures rotation of the circular saw blade 41 . Parallel to the circular saw blade 41 , a spatially fixed, disc-shaped deflecting element 44 is provided, which is slightly conical, as can be seen particularly clearly in FIG. 11. The fixed deflector element 44 is held by a bracket 45 which is arranged, for example, concentrically with the drive shaft 43 . The axis of the circular saw 40 is designated 46 . An arrow 47 defines the direction of rotation of the circular saw blade 41 .

Further details on the structure and function of the circular saw 40 can be found in WO 88/02683, to which reference is made to avoid repetition.

A tree trunk 50 is guided past the circular saw 40 in order to separate side boards 51 from a main item 52 . The tree trunk 50 is only flattened when it reaches the circular saw 40 , but is not profiled in the conventional sense, ie it is not provided with axial corners. The tree trunk 50 is therefore still affected by forest edges 53 .

The side board 51 is now separated from the main item 52 by means of the circular saw 40 . The side board 51 is bent out of the plane of the circular saw blade 41 due to the conicity of the fixed deflecting element 44 , as can be seen particularly clearly in FIG. 11. Due to the taper of the deflecting element 44 , the side board 51 is also slightly offset laterally from the axis of the tree trunk 50 , as can be seen in FIG. 10.

Downstream of the direction of conveyance of the tree trunk 50 indicated by an arrow 54, a trimming unit is arranged directly behind the circular saw 40 . The trimming unit consists of a first (possibly also several) roller pair 60 , a second (possibly also several) roller pair 61 arranged at a distance downstream therefrom as well as a trimmer chipper 62 positioned between the roller pairs 60 , 61 . Immediately upstream of the trimmer 62 , the side board 51 is supported from below by means of an abutment 63 , a so-called counter knife. With 56 , 66 , 67 the axes of rotation of the pairs of rollers 60 , 61 and the trimmer 62 are designated, while arrows 68 , 69 and 70 define their direction of rotation.

The trimmer hogger unit 60 to 63 is arranged somewhat above or next to the main article 52 which continues to run, as shown in FIG. 11. This is possible because, as mentioned, the side board was bent from the plane of separation 51st The pairs of rollers 60 , 61 now cause the side board 51 to bend back in a direction parallel to the conveying direction of the main item 52 .

The side board 51 is trimmed in the trimming unit 60 to 63 and leaves this as a trimmed side board 51 a, as can be seen from Fig. 10.

Since the trimmer hogger unit 60 to 63 is arranged at a distance above or next to the main goods 52 which continue to run, a trimmer hogger 62 with a relatively large diameter D can be used, which is indicated schematically in FIG. 11. The edges of the trimming cutter 62 then run practically at a pressure angle of approximately 45 ° in the radial direction through the wood in the region of the forest edges 53 , the abutment 63 also contributing to the fact that chips of uniform thickness are formed, as already explained further above in FIG. 9 has been.

As a result of the close spatial association of the circular saw 40 and the trimming cutter assembly 60 to 63 , a high degree of dimensional accuracy is also ensured because the side board 51 is still materially connected to the main product 52 when it passes through the trimming cutter assembly 60 to 63 . The trimmed side board 51 a is in fact only cut downstream of the trimming chipper unit 60 to 63 to commercially available lengths. This can be done either by arranging a cross-cut saw (not shown) downstream of the trimming unit 60 to 63 in order to cut the side board 51 a, which is still materially connected to the main goods 52 . On the other hand, it is also possible to first completely separate and trimm the side board 51 from the entire tree trunk 50 , as shown in FIGS . 10 and 11, and then cut it to another location after a separate handling and transport to a cross-cut saw (likewise not shown).

Claims (6)

1. A process for disassembling a tree trunk ( 50 ) in wood products, in which by means of a circular saw ( 40 ) side boards ( 51 ) are separated from a main item ( 52 ) of the tree trunk ( 50 ), the side boards ( 51 ) immediately after Passing the teeth ( 42 ) of the circular saw ( 40 ) by means of a spatially fixed deflecting element ( 44 ) from the plane of the teeth ( 42 ) and subsequently trimmed to a predetermined length, further measures for removing a forest edge ( 53 ) from the tree trunk ( 50 ) are met, in such a way that side boards ( 51 ) are trimmed on both sides, characterized in that the side boards ( 51 ) are cut off in the untrimmed state and immediately after the turning, but before cutting off, a trimmer-cutting unit ( 60 to 63 ) be fed. 2. The method according to claim 1, characterized in that a rotary trimmer chopper ( 62 ) is used as the trimming unit ( 60 to 63 ), the diameter (D) of which is dimensioned such that the side boards ( 51 ) approximately under 45 ° The pressure angle can be moved past the trimmer ( 62 ). 3. The method according to claim 2, characterized in that the side boards ( 51 ) in the engagement region of the trimmer Spaners ( 62 ) by means of an abutment ( 63 ) are supported. 4. Device for dismantling a tree trunk ( 50 ) in Holzer products, with a circular saw ( 40 ) parallel to a circular saw blade ( 41 ) has a fixed deflecting element ( 44 ) which extends into the engagement area of teeth ( 42 ) of the circular saw blade ( 41 ) extends and when separating side boards ( 51 ) from a main item ( 52 ) of the tree trunk ( 50 ) the side boards ( 51 ) immediately after passing the teeth ( 42 ) from the plane of the teeth ( 42 ), the device further comprises first means for removing a forest edge ( 53 ) of the tree trunk ( 50 ) and second means for cutting off the side boards ( 51 ) to predetermined lengths, characterized in that the first means are designed as trimming machiners ( 60 to 63 ) and in the The conveying direction ( 54 ) of the tree trunk ( 50 ) is arranged immediately downstream of the circular saw blade ( 40 ), but upstream of the second means. 5. The device according to claim 4, characterized in that the trimming unit ( 60 to 63 ) comprises a rotating trimmer ( 62 ) whose diameter (D) is dimensioned such that the side boards ( 51 ) approximately at about 45 ° pressure angle can be moved past the trimmer ( 62 ). 6. The device according to claim 5, characterized in that an abutment ( 63 ) for the side boards ( 51 ) is provided in the engagement region of the trimmer ( 62 ).