EP0808236A1

EP0808236A1 - Wood strand manufacturing process and device

Info

Publication number: EP0808236A1
Application number: EP96902976A
Authority: EP
Inventors: Hans Prof. Dr. Dietz
Original assignee: Individual
Current assignee: Individual
Priority date: 1995-02-08
Filing date: 1996-02-02
Publication date: 1997-11-26
Anticipated expiration: 2016-02-02
Also published as: ATE169857T1; WO1996024473A1; DE59600456D1; FI973154A0; AU4717596A; FI107892B; AU692059B2; CA2212575A1; BR9607457A; CA2212575C; CN1173840A; ES2120805T3; NZ301686A; DE19504030C1; EP0808236B1; FI973154A; CN1065809C

Abstract

A process and device are disclosed for manufacturing strands from round wood. The round wood is always an individual tree trunk (30). The tree trunk (30) is fed by a conveyor (50) to a chipping device (51, 52). The chipping device (51, 52) may be made to engage residual areas (33) of the tree trunk (30) that extend beyond its main body (32), so that strands may be cut out of the residual areas (33). The chipping device (51, 52) is provided with first tools (51) which cut longitudinal slots (35) in the residual areas (33, 33').

Description

Method and device -.- πw making strands

The invention relates to a method for producing strands from round wood, the strands having a length between 200 and 350 mm in the fiber direction and a width and thickness between 1 and 15 mm transverse to the fiber direction. The invention further relates to a device for producing strands from round timber, with a transport device for the round timber and with at least one chipper device for cutting the strands, the strands having a length between 200 and 350 mm in the fiber direction and a width and thickness between the fiber direction 1 and 15 mm.

A method and a device of the type mentioned above are known, for example from DE 38 37 200 Cl. It is known. Wood certificates, such as beams or boards, instead of being made from solid wood from chips. In addition to the known particle boards and chip boards, products of this type have become known which consist of so-called "strands", which are also referred to in technical terms as "afer" or "flakes". This is understood to mean, overall, wood chips with relatively large dimensions, compared to wood chips, such as are obtained, for example, when machining side areas, forest edges or the like. Strands typically have a length between 200 and 350 mm in the fiber direction and a width and thickness between 1 and 15 mm transversely to the fiber direction. Wooden products are produced from these beaches by joining and gluing, for example boards or beams, which are then referred to as "composite beams", "beach boards" or "structural lumber products".

For this purpose it is also known to give the strands a specific shape with a defined width, length and thickness, possibly also with defined bevelled edges, so that the strands can be glued in a defined orientation to boards and beams.

A wood-cutting machine for producing such flat chips or beaches is known from DE 38 37 200 Cl mentioned at the outset. The known machine is intended to produce large-area flat chips of a defined thickness, width and length. For this purpose, logs are fed to a chipper drum in a direction perpendicular to their longitudinal extent. The chipper drum comprises an outer cutting rotor and an internal impact rotor concentric with it. The rotors are driven in opposite directions. The cutting rotor cuts out the broad side of the round wood chips that get into the interior of the drum and there are broken down by the impact rotor into the desired flat chips of defined dimensions. The flakes produced in this way are deflected from the inside of the chipper drum by means of a baffle plate and passed onto a conveyor belt.

In the known machine, the diameter of the chipper drum is approximately 60 cm. With the known machine, relatively small logs with a diameter of about 15 cm are processed, that is to say cut pieces of branch and the like. The logs are completely machined.

From US 4,371,020 and US 421 149 a method for producing long beaches is known. In the known method, a log is first pushed in the axial direction through a knife arrangement in which a total of four knives are arranged on diameters of the log and are each offset by 45 °. The log is passed axially through this knife arrangement, so that after passing the knife arrangement, the log is broken down into a total of eight log-segment-shaped logs. These logs are then passed through a fanned arrangement of fixed knives, so that axially parallel strands are created. The strands have a different width in the radial direction. They are therefore subsequently passed through a cutting roller arrangement in which they are broken down into elongated, thin strands which are square in cross section.

In this known method too, the round timber used is completely cut. No. 4,681,146 discloses a method and an apparatus for producing strands. The strands are also made from the round timber already mentioned, in that they are guided with their broad side onto a planer-like table in a feed station. The logs are cut into flake by an oscillating planing board. The flakes are then further cut using knife rollers.

In this known method, the logs are completely machined.

A so-called "profiling method" is known from DE 3114 843 AI. In a profiling process, entire tree trunks are first profiled, that is, machined in the longitudinal direction with corner milling cutters and profile chippers. The result of this processing is a so-called model. This is a wood product with a radial cross-sectional shape that is designed for a subsequent decomposition of the model into boards and beams with optimal wood yield.

The areas machined or machined by the profile chippers and the corner milling cutters are converted in conventional profiling processes into wood chips, as can be further processed in the cellulose industry and the chipboard industry.

From US 4 149 577 a device is known in which several longitudinal slots can be made simultaneously in a tree trunk by means of saw blades.

In contrast, the invention is based on the object of further developing a method of the type mentioned at the outset, that the production of beaches is also possible outside of an area of application in which relatively small round pieces of wood (branches) are completely machined.

According to the method mentioned in the introduction, this object is achieved according to the invention in that the log is in each case a single tree trunk, that the tree trunk is first provided with longitudinal slots in the remaining areas outside a main item of the tree trunk, which are spaced apart from one another by the width, and that the strands are then cut from the entire remaining areas.

The object is further achieved according to the invention by a device of the type mentioned at the outset in that the Treuisport device is designed for transporting individual tree trunks, in that the at least one chipper device can be brought into engagement with the entire remaining areas outside a main article of the tree trunk, and in that the chipper device has first tools for making longitudinal slots in the remaining areas, the longitudinal slots being spaced apart from one another by the width.

The object underlying the invention is completely achieved in this way.

This is because the invention fundamentally dissolves from the previously known methods for producing beaches. These processes were limited to those starting materials, namely round timbers, which were completely machined during the production of strands. Only relatively small logs were considered as starting materials, i.e. cut branches, thicker branches and at most trunks of very young trees. In contrast, the invention extends the field of application of methods for producing beaches or corresponding devices to those woodworking methods in which the solid wood of large logs, namely tree trunks, is only partially machined and the rest of the tree trunk is processed into solid wood products. Such woodworking processes are of great economic importance and are used on a large scale.

While only wood chips or sawdust were produced in the processing of tree trunks in conventional methods and devices, it has become possible for the first time within the scope of the present invention to produce even higher-quality chips, namely strands, in these applications as well.

This is of considerable economic importance for the operators of woodworking plants, because the marketing of secondary products that arise when wood is being processed is becoming increasingly important economically. The production of strands is thus also possible on systems with which entire tree trunks have conventionally been processed with the production of chips. For this purpose, only relatively small conversions or additions to existing systems are required. The economy of these systems can therefore be increased significantly with little effort.

In a first alternative development of the above-mentioned method, the beaches are cut in a single operation between the longitudinal slots by machining with a length of 1 along transverse slots that have been introduced simultaneously and with a thickness d. The same applies to an embodiment of the device according to the invention, in which the chipper device downstream of the in the transport direction the first tools have chippers that cut the strands in a single operation between the longitudinal slots by machining with a length of 1 along transverse slots that are simultaneously inserted and with a thickness d.

In a second alternative of this exemplary embodiment of a method according to the invention, on the other hand, after the longitudinal slots have been made, the remaining areas are first provided with transverse slots in a first working step, which are spaced apart by the length 1, and the strands are then cut in a second working step with the thickness d . The same applies to an associated exemplary embodiment of the device according to the invention, in which the chipper device has second tools for making the transverse slots in the remaining areas, the transverse slots being spaced apart by the length 1, and downstream in the transport direction of the first tools and the second Tools includes third tools for cutting the beaches with the thickness d.

The above-mentioned measures have the advantage that strands with dimensions which can be varied over a wide range can be produced in two alternative procedures, the dimensions being precisely predetermined according to length, width and thickness. By appropriate shaping of the tools, bevelled or otherwise profiled beaches can also be created.

Also preferred is an embodiment of a method according to the invention, in which the beaches are first cut on two opposite sides of the tree trunk and then on the two opposite sides of the tree trunk offset by 90 °. This measure has the advantage that sequences of work steps known per se, as are known in profiling processes, can be used. For example, two processing stations located one behind the other in the transport direction can be used, between which the already partially processed tree trunk is rotated by 90 ° about its longitudinal axis. Alternatively, it is possible to provide only one such processing station and, after leaving the processing station, to rotate the tree trunk by 90 ° and to lead it back to the entrance of the processing station by means of a rotary run.

In preferred embodiments of the method according to the invention, the longitudinal slots are produced as longitudinal cuts by cutting. Alternatively, the longitudinal slots can also be created by sawing.

In a corresponding manner, it is possible to produce the cross slots as cross sections by cutting or the cross slots by sawing.

In embodiments of the device according to the invention, the first tools are accordingly designed alternatively as first knives or as first saws, while the second tools can be designed as second knives or alternatively as second saws.

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

1 is a side view, greatly simplified, of a device for producing strands according to the prior art; 2 shows an individual beach, in perspective representation, greatly enlarged;

3 shows a perspective side view of a tree trunk to be processed;

FIGS. 4 and 5 show two schematic side views, similar to FIG. 3, to explain successive work steps in one embodiment of the method;

Figures 6 to 11

Radial sections through tree trunks according to the representations of Figures 4 and 5 to explain successive processing steps;

12 shows a perspective side view of an exemplary embodiment of a device.

In Fig. 1, 10 generally designates a conventional device for making strands. By means of a feed 11, in which a slide 12 runs, logs 13 are pushed through the feed 11 in the direction of an arrow 14. The logs 13 are conveyed transversely to their longitudinal axis.

A rotating chipping tool 20 is located directly at the outlet of the feed 11. The chipping tool 20 is driven in the direction of rotation by means of a shaft 21, as indicated by an arrow 22. Knives 23, which protrude beyond the circumference of the chipper tool 20, are located on the circumference of the chipper tool 20. The laterally supplied logs 13 thus come into the engagement area of the rotating knives 23, as indicated by dashed lines in FIG. 1. In this way, individual flat chips or strands 24 are cut or cut by the logs 13 and leave the device 10 in the direction of arrows 25.

The illustration in Fig. 1 is extremely schematic. It goes without saying that the strands 24 shown can still be reworked in further stations, for example further divided, profiled on their edges, etc., as is known in detail from the prior art cited at the beginning.

FIG. 2 shows a beach 24 in an enlarged representation to illustrate the difference to conventional wood chips or other chips. An end face 26 of the beach 24 clearly shows fibers 27 of the wood. The length 1 of the beach 24 in the fiber direction is significantly greater than the width b or the thickness d, in each case transverse to the fiber direction.

In practice, strands have a length 1 between 100 and 350 mm, a width b between 1 and 15 mm and a thickness d between 1 and 6 mm. However, deviations from these values are also possible.

Unlike shown in FIG. 2, the strands 24 can also have a non-cuboid shape, for example a prismatic or other shape, so that individual strands 24 are joined together in a defined orientation and positioning and glued to composite beams or boards, so-called "beach boards" can be.

Fig. 3 shows in a schematic representation of a log 30, namely a complete tree trunk. On an end face 31 at the thin end of the tree trunk 30, a main item 32 is shown. This is an area with a rectangular or square cross-sectional area in the center of the tree trunk 30. The associated area corresponds to the area of the tree trunk 30 from which the said main goods 32, namely beams, boards and the like, are produced.

The remaining remaining areas 33 are partly processed into side boards in the case of conventional profiling processes, and partly cut by means of wood chip production and sawing.

The special feature of the present method is that the remaining areas 33 shown are completely or partially broken down into strands 38.

For this purpose, the remaining areas 33 are provided with longitudinal cuts 35 and cross sections 36 so that the strands 38 can be cut into layers 37. In this way, strands 38 are produced whose length 1, width b and thickness d are defined.

If the term "cuts" is used in the context of the present application, that is to say, for example, the longitudinal cuts 35 and the cross-sections 36, this is only to be understood as an example. In general, the tree trunks can be provided with slots, the slots being able to be made either by means of knives as cuts or by means of saws.

The details of the method used and the device used here will now be explained below with reference to FIGS. 4 to 12. FIGS. 4 and 5 show two schematic perspective side views of the tree trunk 30, FIGS. 6 to 11 cross-sectional views through the tree trunk 30 during various processing steps, and FIG. 12 finally shows a perspective view of a device used. To process the tree trunk 30, the longitudinal cuts 35 are first made according to FIGS. 4 and 6. For this purpose, the tree trunk 30 is guided in the longitudinal direction by two groups of fixed knives 51 using a transport device 50, which is indicated only schematically as arrows in FIG. 12. The knives 51 produce the longitudinal cuts 35 in the tree trunk 30, down to a boundary line 40 shown in FIG. 6, which is also a side edge of the main article 32. As can be clearly seen from FIGS. 6 and 12, the longitudinal cuts 35 are made, for example, simultaneously on two opposite sides of the tree trunk 30.

In the sense of the explanations above, the knives 51 are only to be understood as an example. Corresponding saws can of course also be used instead of the knives 51 for making the cuts in order to make corresponding slots.

There are now two alternatives for further processing of tree trunk 30:

According to the first alternative, the cross sections 36 are attached to the tree trunk 30 in a separate operation, as shown in FIG. For this purpose (not shown), corresponding groups of cutting knives can be used, which are guided transversely to the longitudinal direction of the tree trunk 30 to the depth of the boundary line 40. The tree trunk 30 would then have the appearance shown in FIG. 3.

To cut the beach 38, the tree trunk 30 could then be run against a stepped group of fixed knives which are oriented in the transport direction, that is to say the longitudinal direction of the tree trunk 30, and cut the beach 38 already defined according to length 1 and width b to a predetermined thickness. A such a device is described, for example, in US 4,371,020, already explained at the beginning.

According to the second alternative, which is preferred in the present context, the cross sections 36 are made in a single operation together with the cutting of the strands 38. The chippers 52 shown by way of example in FIG. 12 serve this purpose. The chippers 52 are driven by means of shafts 53. The shafts 53 extend along axes 54 transversely to the longitudinal extent of the tree trunk 30. In the exemplary embodiment shown, the chippers 52 rotate in the direction of arrows 55. The chippers 52 are provided with conical machining surfaces. Knives 60, which each have a main cutting edge 61 and a secondary cutting edge 62, are located on the multiple aisles of the conical machining surfaces. The main cutting edge 61 and the secondary cutting edge 62 can also be formed by separate knives which are distributed over the circumference. In this way, in the exemplary embodiment shown, the remaining area 33 next to the main item 32 can be machined on both sides of the tree trunk 30.

As a result of the taper of the surfaces of the chipper 52, the remaining areas 33 are removed in layers, as is indicated in FIG. 7 by dash-dotted cut lines 42. Appropriate shaping and positioning of the main cutting edge 61 and the secondary cutting edge 62 make it possible in this way to cut the strands 38 with an adjustable length 1 and thickness d. FIG. 7 shows a state in which the two remaining areas 33 have already been cut to about a third to form strands 38. This state of the tree trunk 30 is designated by 30a in FIG. 7.

8 shows the state 30b of the tree trunk 30, in which the two remaining areas 33 mentioned have been completely removed. One side 44 of the main item 32 is thus already fully formed. The tree trunk 30 is now rotated by 90 ° about its longitudinal axis and thus reaches the position shown in FIG. 9. In this position, the tree trunk 30 is again provided with longitudinal cuts 35 'by means of the arrangement according to FIG. 12 in the remaining areas 33' now lying to the side (state 30c). For this purpose, the device according to FIG. 12 can be arranged twice in the transport direction of the tree trunks 30. Between the two devices, either the tree trunk 30 can be rotated by 90 °, or the two individual devices can be rotated by 90 ° to one another. However, it is also possible to turn the tree trunk 30 through 90 ° after leaving the arrangement shown in FIG. 12 and to return it to the input of the device according to FIG. 12 by means of a rotary run.

The tree trunk 30 processed in this way is then again machined in the longitudinally cut remaining areas 33 ', as shown in FIG. 10 with state 30d. Cut lines 42 'and the cut strands 38' can also be seen here. At the end of the work step that is partially completed in FIG. 10, the main item 32 is finished, as shown in FIG. 11.

According to the method explained above, the remaining areas 33, 33 'are completely broken down into strands 38, 38'. However, it goes without saying that only partial dismantling of the remaining areas 33, 33 'is possible if, for example, parts of the remaining areas 33, 33' are to be processed into boards. The corresponding engagement depths (boundary lines 40) must then be set accordingly.

Claims

claims

1. A method for producing strands (24; 38, 38 ') from round wood (13), the strands (24; 38, 38') in the fiber direction having a length (1) of between 200 and 350 mm and transverse to the fiber direction have a width (b) and thickness (d) of between 1 and 15 mm, characterized in that the log (13) is in each case a single tree trunk (30), that the tree trunk (30) initially has longitudinal slots in the outside of a main item ( 32) of the tree trunk (30) lying residual areas (33, 33 '), which are spaced apart by the width (b), and then the strands (38, 38') from the entire remaining areas (33, 33 ') get cut.

2. The method according to claim 1, characterized in that the strands (38, 38 ') are cut in a single operation between the longitudinal slots by machining with the length (1) along simultaneously inserted transverse slots and with the thickness (d).

3. The method according to claim 1, characterized in that the remaining areas (33, 33 ') after attaching the longitudinal slots are first provided in a first operation with transverse slots which are spaced apart by the length (1), and then the strands (38, 38 ') are cut with the thickness (d) in a second operation.

4. The method according to one or more of claims 1 to

3, characterized in that the strands (38, 38 ') are first slit on two opposite sides of the tree trunk (30) and then on the two opposite sides of the tree trunk (30) which are offset by 90 °.

5. The method according to one or more of claims 1 to

4, characterized in that the longitudinal slots are produced as longitudinal cuts (35, 35 ') by cutting.

6. The method according to one or more of claims 1 to 4, characterized in that the longitudinal slots are produced by sawing.

7. The method according to one or more of claims 3 to 6, characterized in that the transverse slots as Quer¬ cuts (36) are produced by cutting.

8. The method according to one or more of claims 3 to 6, characterized in that the transverse slots are produced by sawing.

9. Device for producing strands (24; 38, 38 ') from round wood (13) with a transport device (11, 12; 50) for the round wood (13) and with at least one chipper device (20; 51, 52) for cutting the strands (24; 38, 38 '), the strands (24; 38, 38') in the fiber direction having a length (1) between 200 and 350 mm and transversely to the fiber direction a width (b) and thickness ( d) have between 1 and 15 mm, characterized in that the transport device (50) is designed for transporting individual tree trunks (30), that the at least one chipper device (51, 52) engages with the entire remaining areas (33, 33 ') can be brought outside a main item (32) of the tree trunk (30), and that the chipper device (51, 52) has first tools for making longitudinal slots in the remaining areas (33, 33'), the longitudinal slots extending around the width ( b) are spaced apart.

10. The device according to claim 9, characterized in that the chipper device (51, 52) in the transport direction downstream of the first tool chipper (52), the strands (38, 38 ') in a single operation between the longitudinal slots by machining with the Cut length (1) along transverse slots and cut with thickness (d).

Device according to claim 9, characterized in that the chipping device (51, 52) has second tools for making transverse slots in the remaining areas (33, 33 '), the transverse slots being spaced apart from one another by the length (1) and in Transport direction downstream of the first tools and the second tools comprises third tools for cutting the strands (38, 38 ') with the thickness (d).

12. The device according to one or more of claims 9 to 11, characterized in that the first tools are designed as first knives (51) which make the longitudinal slots as longitudinal cuts (35, 35 ').

13. The device according to one or more of claims 9 to 11, characterized in that the first tools are designed as first saws.

14. The device according to one or more of claims 11 to 13, characterized in that the second tools are designed as second knives, which make the transverse slots as cross sections.

15. The device according to one or more of claims 11 to 13, characterized in that the second tools are designed as second saws.