Milling head for profiling tree trunks

Abstract

A milling head (10, 110) for profiling tree trunks has two rotating processing tools (12, 14; 112, 114) whose axes of rotation run parallel to each other, except for any differing angles of inclination of the processing tools (12, 14; 112, 114). The processing tools (12, 14; 112, 114) are each designed to produce a circumferential and an end-face processing surface. The position of the circumferential processing surfaces of the two processing tools (12, 14; 112, 114) relative to the tree trunk being processed is adjustable independently of the other processing tool (12, 14; 112, 114). With such an adjustable milling head, a variable double step can be created on each side of the trunk for the subsequent removal of two side boards, which can be optimized independently of each other based on the trunk contour.

Description

[0001] The present invention relates to a milling head for profiling tree trunks. The invention also relates to a method for producing side boards from a tree trunk, in which the tree trunk is first clamped on all four sides, then corner areas are milled out, and side boards bounded by the milled corner areas are cut off by means of a saw.

[0002] In modern sawmill technology, logs are first optically measured before sawing, and an optimized cutting solution is determined for each log based on the three-dimensional measurement data. The actual processing of the log then takes place during a feed movement. The log is first clamped on all four sides using so-called chippers. Subsequently, any bare corner areas are milled out. This is done using corner cutters, requiring four milling heads on each side, above and below the side board to be produced. The side boards, bordered by the milled corner areas, are then cut off by a saw. The sawing of the resulting log typically follows the curvature of the trunk. For this purpose, the log, clamped on all four sides and with the corner areas milled out, is guided through a saw following its curvature.A corresponding processing method is described, for example, in EP 2 743 023 A1.

[0003] If two side boards are to be produced on each side, they are either created sequentially by milling and sawing the first board and then milling and sawing the second board. Alternatively, both side boards can be cut off in a single sawing operation. However, for this to work, two stepped corner sections must be milled out at each corner before sawing; that is, a first corner section is milled out with one machine and then a second corner section is milled out with a second machine.

[0004] The two milling machines are therefore arranged one behind the other in the direction of transport. Consequently, the system becomes longer, and, depending on the curvature of the logs, larger lateral deflections of the milling heads further away from the saw must be accepted, since the point of tangency of the log's curvature curve must lie within the saw when sawing following the curve. Providing larger adjustment ranges for the corner milling heads is structurally complex and increases the time required to adjust the corner milling heads to the next log, which in turn necessitates larger log spacing between passes and thus reduces the system's throughput.

[0005] Stepped milling heads are also known on the market. These heads feature two sets of blades arranged at a fixed distance from each other on a rotating tool, allowing for the milling of a stepped corner contour on a log. However, the distance between the two steps is fixed, meaning that only side boards of a predetermined thickness and width difference can be produced. This reduces flexibility in optimizing the cutting solution and, consequently, lowers the wood yield in favor of higher throughput. Milling side boards with different dimensions requires retooling the machine, resulting in downtime.

[0006] One object of the invention is therefore to provide a device with which two side boards per side of a log can be produced, enabling a compact design of the system equipped therewith and allowing a higher throughput without reducing the wood yield. A further object of the invention is to provide a corresponding method for producing side boards from a log.

[0007] The problem is solved with regard to the device by a milling head having the features of claim 1 and with regard to the method by the features of claim 12. Advantageous embodiments can be found in the dependent claims.

[0008] According to the invention, a milling head for profiling tree trunks has two rotating processing tools whose axes of rotation run parallel to each other, except for any differing angles of inclination of the processing tools. The processing tools are each designed to produce a circumferential and an end-face processing surface, and the position of the circumferential processing surfaces of the two processing tools relative to the tree trunk being processed can be adjusted independently of the other processing tool. With such an adjustable milling head, a variable double step can be created on each side of the trunk for the subsequent removal of two side boards, which can be optimized independently of each other based on the trunk contour.

[0009] Preferably, the two processing tools can also be arranged to be adjustable relative to each other in the direction of their axes of rotation, so that the respective position of the end-face processing surfaces in relation to the log being processed can be adjusted independently of the other processing tool. This allows side boards with independently adjustable thicknesses to be produced.

[0010] In a first preferred embodiment, the adjustability of the machining tools is achieved by mounting one of the machining tools directly and the second machining tool via an eccentric on a common tool carrier. The position of the circumferential machining surface of the first machining tool relative to the log being machined can be adjusted by moving the tool carrier, and the position of the circumferential machining surface of the second machining tool relative to the log being machined can be adjusted by rotating the eccentric or the tool carrier. Such a design is extremely compact and requires few moving parts, making the milling head resistant to contamination and thus ensuring high reliability.

[0011] In a particularly advantageous further development, the rotary drive of the two machining tools is provided by a common drive unit, and the machining tools are rotaryally coupled to each other via a gearbox housed within the eccentric. This results in a particularly simple and compact design, requiring only one drive unit.

[0012] In a second, alternative embodiment, the two machining tools can also be mounted on separate tool holders. In this case, the position of the circumferential machining surface of each of the two machining tools relative to the log being machined can be adjusted by moving the corresponding tool holder. Separate tool holders allow the two machining tools of the milling head to be adjusted independently of each other, resulting in a high degree of flexibility in the dimensioning of the side boards. Adjusting the tool holder here also means that only a sub-component of the tool holder is moved. The less mass that needs to be moved during an adjustment movement, the faster and more energy-efficient this can be done.

[0013] In a particularly advantageous further development, even in the second embodiment with the machining tools mounted on separate tool carriers, the rotary drive of both machining tools can be achieved via a common drive unit, by rotaryally coupling the machining tools to each other via a driveshaft. Thus, in this case as well, only one drive unit is required.

[0014] In a particularly preferred embodiment of the invention, the rotary drive of the two machining tools is synchronized, and each machining tool is divided into tool segments, with the tool segments of the two machining tools meshing with each other. Due to the synchronized rotary drive, the interlocking tool segments do not interfere with each other, allowing the machining tools to be moved relative to each other for variable adjustment of the milling geometry. Besides a compact design, this enables a large adjustment range of the machining tools. While synchronization of the separate rotary drives for the machining tools would be possible in principle, synchronicity can be achieved, particularly as described above, by a common rotary drive with rotary coupling of the machining tools.

[0015] With the same number of tool segments, the machining tools can be driven at the same angular velocity. With a different number of tool segments, the angular velocities of the two machining tools are inversely proportional to the number of tool segments per tool. This ratio of angular velocities can be easily achieved through an appropriate gear ratio in the rotary coupling of the machining tools.

[0016] In a preferred embodiment, the two machining tools have different diameters, and the axis of rotation of the second, smaller-diameter machining tool runs within the cross-sectional area of ​​the first, larger-diameter machining tool and is offset from its axis of rotation. This allows for very simple and compact adjustment of step geometries.

[0017] Advantageously, the tool segments of both processing tools may each comprise at least one circumferentially arranged chopping blade and one end-mounted circular saw segment. Circumferential chopping blades produce a clean circumferential surface, while the circular saw segments produce an end-mounted surface without tear-out in the wood.

[0018] In the case of end-mounted circular saw segments, the service life can be increased by designing the length of some teeth within a segment—that is, the radial distance of the saw tooth tips to the axis of rotation of the milling head within the saw segments—to increase against the direction of rotation. This means that the front teeth do not have to perform the highest cutting performance and therefore do not wear out prematurely.

[0019] In the circumferential direction, the tool segments of the processing tools can have two or more chipping blades arranged radially and axially offset, whose cutting areas overlap or at least abut each other. This distributes the cutting power across multiple chipping blades, which also increases their service life and enables a larger processing area. Furthermore, the geometry of the chipping blades allows for the production of wood chips with predefined geometric requirements, which can be further processed in various industrial applications, thus offering additional value. The thickness of the wood chips is determined by the feed rate of the log, the number of chipping blades in the circumferential direction, and the rotational speed of the milling head.

[0020] If the rotary drive of the machining tools is powered by a common drive unit, the power transmission from this unit to one of the tools can be achieved via a drive belt. A belt drive allows for high torque, is simple and robust, and less susceptible to contamination. Alternatively, other power transmission methods, such as a drive chain or a direct drive, are also possible.

[0021] In the inventive method for producing sawn timber, the log is first clamped on all four sides, then corner areas are milled out, and side boards bounded by the milled corner areas are cut off using a saw. According to the invention, in the milling step, stepped corner areas are milled out using milling heads of the type described above, and in the subsequent sawing step, two side boards bounded by the stepped corner areas are cut off on each side of the log. For each log, the position of the circumferential machining surfaces of the two machining tools of each milling head is set independently of the other machining tool of the milling head.

[0022] Preferably, the log is optically measured three-dimensionally before or after machining, and an optimized cutting solution, including the side boards, is determined based on the measurement data. The position of the circumferential machining surfaces of the milling heads is then adjusted to the dimensions determined for the side boards in the cutting solution.

[0023] In a preferred further development, the log is guided through the saw following its curvature by means of adjustable transport and guide rollers. During this process, the milling heads are guided along the log in such a way that the resulting milled contour corresponds to the shape of the side boards determined within the cutting solution. This curvature-following cut significantly increases the yield. To ensure that the tangent point of the cutting curve lies within the saw and thus reduces lateral forces on the saw blades, the milling heads are guided along the log as it passes through. This allows for the production of not only side boards oriented parallel to the log axis, but also side boards oriented at an angle to the log's curvature, or side boards with a pre-calculated longitudinal bend across their narrow side (crook).

[0024] The milling step using milling heads according to the invention can be carried out either before separating side boards in the pre-cutting process, or before splitting the log into main and side boards in the post-cutting process, or in both cases. In other words, the log can be profiled using the milling heads according to the invention to produce both two pre-cut side boards per side and two side boards per side in the post-cutting process.

[0025] Further advantages and features will become apparent from the following description of exemplary embodiments based on the figures. It shows: Fig. 1 an isometric view of a milling head with associated drive unit in a first embodiment with eccentrically mounted inner machining tool, Fig. 2 a top view of the milling head from Fig. 1, Fig. 3 a sectional drawing along line A - A in Fig. 2, Fig. 4 an isometric view of the disassembled milling head made of Fig. 1 with its outer rotating machining tool, Fig. 5 an isometric view of the in Fig. 4 disassembled inner rotating machining tool with the eccentric on which it is mounted, Fig. 6 an isometric representation of an eccentric from Fig. 5 recorded gearbox for rotary coupling of the two machining tools of the milling head, Fig. 7 an isometric view of a milling head with associated drive unit in a second embodiment with separate tool carriers for its two machining tools, Fig. 8 a top view of the milling head Fig. 7, Fig. 9 a sectional drawing along line A - A in Fig. 8, Fig. 10 an isometric view of the disassembled inner machining tool of the milling head made of Fig. 7 with associated tool carrier and a drive shaft for rotary coupling of the machining tools, Fig. 11 an isometric view of the milling head from Fig. 8 without the disassembled inner machining tool Fig. 10, Fig. 12 a rear view of the partially disassembled milling head made of Fig. 11, Fig. 13 a simplified schematic drawing to illustrate the operating principle of the second embodiment; Fig. 14 a simplified schematic drawing to illustrate the operating principle of the first embodiment; Fig. 15 and Fig. 16 A simplified schematic drawing in front and side view to illustrate an optional tool tilt.

[0026] In the Fig. 1, Fig. 2, Fig. 3, Fig. 4, Fig. 5 to Fig. In the first embodiment shown in Figure 6, a milling head 10 has a first, outer rotating machining tool 12 and a second, inner rotating machining tool 14, which has a smaller diameter than the outer machining tool 12.

[0027] The outer machining tool 12 is supported by a hollow shaft 16, which is driven by a drive motor 20 via a drive belt 18, thus rotating the machining tool 12 during operation. In an alternative embodiment not shown here, it is also conceivable to use an alternative element for power and motion transmission instead of a drive belt 18, or to arrange the drive motor 20 such that it directly drives the hollow shaft 16.

[0028] The hollow shaft 16 is rotatably mounted on a tool carrier 22. The tool carrier is adjustable in the x and z directions via linear actuators and corresponding guides (not shown) in a manner known per se, with the y direction representing the transport direction of a log to be processed.

[0029] Inside the hollow shaft 16 there is an eccentric 24 ( Fig. 5), against which the hollow shaft 16 is rotatably mounted. This carries the inner machining tool 14. The eccentric 24 is mounted on a toothed slewing ring 26, which can be rotated by a servo motor 30 via a pinion 28. It would also be conceivable, though not shown here, to rotate the eccentric 24 not via the slewing ring 26 and the servo motor 30, but by means of a fundamentally different actuating device. For example, a lever element could be used, which is connected to the eccentric 24 instead of the slewing ring 26 and can be actuated by means of a servo-hydraulic actuator.

[0030] The two machining tools 12 and 14 are milling units of the milling head. Each is divided into three tool segments 12a, 12b, 12c and 14a, 14b, 14c. The tool segments 12a, 12b, 12c of the outer machining tool 12 each have three radially and axially offset chopping blades 13a and a circular saw segment 13b at the end face. When used on a tree trunk, the machining tool 12 thus creates an end-face machining surface via the circular saw segments 13b and a circumferential machining surface via the chopping blades 13a, which are oriented perpendicular to each other. In a manner not shown here, instead of three tool segments 12a, 12b, 12c or 14a, 14b, 14c, fewer or more tool segments can be provided, distributed around the circumference, in particular in a number between two and eight, so that, for example, six tool segments can also be present.It is also conceivable that fewer or more than three chopping knives 13a are provided per tool segment 12a, 12b, 12c or 14a, 14b, 14c.

[0031] Accordingly, the tool segments 14a, 14b, 14c of the inner processing tool 14 each have two radially and axially offset chopping knives 15a and a front-facing circular saw segment 15b, which, when used on a tree trunk, create a front-facing and a perpendicular circumferential processing surface.

[0032] From above Fig. Figure 2 clearly shows the tool segments and their end-face circular saw segments. It is also evident that the eccentric 24 ensures that the axes of rotation of the two machining tools 12 and 14 run parallel to each other but are offset from one another. If one imagines a tree trunk, for example, along arrow T, the tool segments of the outer machining tool 12 penetrate deeper into the trunk than the more distant tool segments of the machining tool 14, resulting in two stepped corners being milled into the tree trunk. By rotating the eccentric 24, the axis of rotation is moved closer to the tree trunk, which runs along arrow T, thus reducing the distance between the circumferential machining surfaces on the tree trunk.The cutting depth of the outer machining tool 12 can thus be adjusted by adjusting the tool carrier 22, the cutting depth of the inner machining tool 14 by additionally rotating the eccentric 24 via the rotary ring 26.

[0033] As an alternative to rotating the eccentric 24, the entire tool carrier 22 can of course also be rotated with or without the drive unit 20, which would be more technically complex to implement, but would have the same effect of a relative rotation of the eccentric to the tree trunk.

[0034] In the sectional drawing in Fig. Figure 3 shows how the hollow shaft 16 is mounted around the eccentric 24. A hub 32 is mounted on the rotary ring 26. The hollow shaft 16 is rotatably mounted around this hub by two axially spaced bearings 34. The drive belt 18 runs around the hollow shaft and a pulley 19, which is driven by the drive motor 20 to rotate the hollow shaft 16. The drive motor 20, the details of which are not relevant here, is shown hatched throughout in the section for simplicity. The end of the hollow shaft 16 carries a tool holder 17 on which the outer machining tool 12 is mounted.

[0035] The shaft 24a of the eccentric 24 runs within the hub. This shaft is coupled to the hub 32 in a rotationally fixed but axially displaceable manner. The cylindrical head section 24b of the eccentric 24 is offset from the axis of the eccentric shaft 24a, so that by rotating the eccentric axis, the distance between the eccentric head 24b and the log being processed is adjusted. A hub 36 is arranged on the eccentric 24, on which the upper or inner processing tool 14 is rotatably mounted by means of two rolling bearings 38.

[0036] The rotary drive of the inner machining tool 14 is effected via a [missing information] in the Fig. 6 and Fig. Figure 7 shows a more detailed gearbox 40, which is housed inside the eccentric 16. This gearbox comprises a ring gear flange 41, which is connected to the hollow shaft 16, for example, via a keyway and sealed against it by a seal 41a. The ring gear flange 41 has internal teeth into which a first gear 42 engages. This is connected via a transmission shaft 43 to a second gear 44, which drives a ring gear 45 connected to the hub 36. Thus, the rotary drive of the inner machining tool 14 is synchronized with the outer machining tool 12.

[0037] In the Fig. 4 and Fig. Figure 5 shows the milling head disassembled. Fig. Figure 4 shows only the hollow shaft 16 with the outer machining tool 12 and the tool holder 22, as well as the rotary ring 26 and the actuator 30 with pinion 28. The eccentric 24 with gearbox 40 and the inner machining tool 14 is shown disassembled. This unit is in Fig. 5 shown. Fig. Figure 4 shows that the tool segments 12a, 12b, 12c are each separated by larger circumferential gaps. These are larger than the width of the chopping blades 13a of the Fig. The 5 tool segments 13a, 13b, 13c of the inner machining tool 13 are shown. This allows the tool segments 13a, 13b, 13c to plunge into the gaps between the segments 12a, 12b, 12c, so that the tool segments 12a, 12b, 12c, 14a, 14b, 14c of the two machining tools 12, 14 interlock during synchronized rotary movement.

[0038] The two machining tools 12, 14 can thus be adjusted relative to each other and into each other within a certain adjustment range. For this purpose, the eccentric 24 is designed to be axially movable and is connected to the piston rod 47 of a hydraulic cylinder 46. The hydraulic cylinder 46 thus serves as a linear drive to adjust the machining tools 12, 14 relative to each other by axially adjusting the eccentric. In this way, the respective position of the end faces of the machining tools 12, 14 relative to a tree trunk to be machined can also be adjusted independently of the other machining tool, namely the end face of the outer machining tool 12 by adjusting the tool holder 22 and the end face of the inner machining tool 14 by axially adjusting the eccentric 24 via the hydraulic cylinder 46.

[0039] A second embodiment of a milling head 100 with two rotating machining tools 112, 114 is described in the Fig. 7, Fig. 8, Fig. 9, Fig. 10, Fig. 11 to Fig. Figure 12 shows the outer milling head 112 rotatably mounted in a housing 116. The housing 116 is guided by a rail 120a, 120b (see Figure 12). Fig. 12) adjustable on a first tool carrier 122.

[0040] The outer milling head 112 is driven via a shaft 118 equipped with a pulley 119, which is driven by a drive motor 124 via a drive belt 121. Since the shaft 118 undergoes a change in length when the housing 116 is adjusted, this can be achieved by a cardan shaft or a splined shaft with an axially displaceable toothed hub. A cardan shaft would not actually have to compensate for an angular misalignment, but as mentioned, only for a change in length. However, it offers the advantage that the required tolerances between the pulleys 119 and the mounting of the machining tool 112 need to be less tight.

[0041] Instead of the housing 116, the entire tool carrier 122, including the drive motor 124, could of course be adjusted. Length compensation for the shaft 118 would then be unnecessary. However, this would require moving a significantly larger mass, which would necessitate correspondingly more drive energy or longer adjustment times.

[0042] The inner machining tool 114 is mounted on a bearing carrier 126. This is adjustable in the x-direction via a rail guide 128a, 128b on a second tool carrier 130. The second tool carrier 130 is in turn longitudinally movable in the z-direction on the housing 116 via a rail guide 132a, 132b. Linear drives 134, 136 (see Fig. 8) The bearing carrier 126 can be adjusted relative to the second tool carrier 130 in the x-direction, and the second tool carrier 130 can be adjusted relative to the housing 116 in the z-direction. Thus, the inner machining tool 114 can be positioned arbitrarily within an adjustment range, independent of the position of the outer machining tool 112.

[0043] The positioning of the outer machining tool 112 is achieved by external positioning of the tool carrier 122 in the x-direction and by adjusting the housing 116 relative to the tool carrier 122 in the z-direction by means of corresponding linear drives (not shown).

[0044] The inner machining tool 114 is driven by rotary coupling with the outer machining tool 112. As shown in the sectional drawing in Fig. As can be seen in Figure 9, the shaft 118 drives a flange 138, which is rotatably mounted in the housing 116 via the bearing 140. Towards its end, the rotatable flange 138 widens and carries a tool holder 142, on which the tool segments 112a, 112b, 112c of the outer machining tool 112 are arranged. As in the first embodiment, the tool segments 112a, 112b, 112c each comprise three chopping blades 113a arranged radially and axially offset in the circumferential direction and a circular saw segment 113b at the end face.

[0045] The inner machining tool 114, as in the first embodiment, is also divided into three tool segments 114a, 114b, 114c, each comprising two offset chopping blades 115a and a circular saw segment 115b at the end face. These are supported by a tool holder 144, which is rotatably mounted about a hub 146 located on the bearing support 126. The rotary coupling of the tool holder 144 of the inner machining tool 114 with the rotatable flange 138, which supports the outer machining tool 112, is achieved by a Fig. 9. A drive shaft 148 runs obliquely within the flange 138. The drive shaft 148 comprises two universal or ball joints 148a, 148b for angular compensation and a sliding piece connecting the universal or ball joints 148a, 148b for length compensation. It compensates for an offset between the axes of rotation of the outer and inner machining tools 112, 114, which can be adjusted by adjusting the bearing carrier 126, and also enables length compensation when the tool carrier 130 is adjusted in the z-direction relative to the tool carrier 122 or the housing 116 movably mounted on it.

[0046] As in the first embodiment, the rotary coupling of the machining tools 112, 114 by means of the drive shaft 148 ensures a synchronized rotary movement, so that the tool segments 112a, 112b, 112c, 114a, 114b, 114c of the two machining tools 112, 114 can mesh with each other. The two machining tools 112, 114 can thus also be adjusted relative to each other and into each other within a certain adjustment range.

[0047] Based on Fig. Section 13 will explain again the operating principle underlying the second embodiment. The milling head 200 has two rotatable machining tools 201, 202, an inner and an outer one. The outer machining tool 201 is mounted on a first tool carrier 203, and the inner machining tool is mounted on a second, separate tool carrier 204. Both are independently adjustable in the x and z directions. The two machining tools are rotaryally coupled via a driveshaft 205, so that both can be driven by a drive motor that is coupled to one of the two machining tools.

[0048] Furthermore, a schematic representation of a four-sided log 206, a so-called "cant," is shown, which may still have bark-edged areas that are milled out with the milling head according to the invention in order to subsequently separate so-called side boards. The log 206 is transported here against the milling head 200 in a direction out of the plane of the drawing (y-direction), i.e., it is guided past the stationary milling head 200 and its machining tools 201, 202. Each of the machining tools 201, 202 mills a corner profile with two perpendicular machining surfaces from the log 206. A side board can then be separated from each of the perpendicular edges of the corner profiles by a saw cut.

[0049] Each corner profile has a circumferential machining surface 207, 208 and an end-face machining surface 209, 210, relative to the respective machining tool 201, 202. The positions of the corner areas can be adjusted independently of each other. For this purpose, both tool carriers 203, 204 can be adjusted in the x and z directions. Adjustment in the x direction (vertical in the drawing) determines the width and position of the side board relative to the log 206, while adjustment in the z direction (horizontal in the drawing) determines the board thickness. Adjustment in the x direction can also be controlled during the passage of a log 206. In this way, a side board with an angled profile relative to the log axis or a side board curved along its long narrow side (crook) can be produced, for example, to optimize the wood yield depending on the log curvature.

[0050] In Fig. Figure 14 shows a comparable schematic diagram, which serves to summarize the operating principle underlying the first embodiment. The milling head 220 shown there again has a first, outer machining tool 221 and a second, inner machining tool 222. These are mounted eccentrically to each other and rotaryally coupled, so that only the outer machining tool 221 needs to be driven. The outer machining tool 221 is adjustable in the x and z directions via a common tool carrier (not shown here). The inner machining tool is adjustable in the z direction (horizontally in the drawing plane). In addition, the eccentric axis can be rotated, thereby adjusting the cutting depth of the inner machining tool (x direction) and thus the width and position of the respective side board relative to the tree trunk 226.

[0051] The Fig. 14 and Fig. Figure 15 shows two further schematic diagrams, which are intended to explain any existing inclination angles of the machining tools. Fig. Figure 14 shows a log 236 with a milled profile in cross-section. At each of the four corners, a double corner profile is milled out as described above. Four milling heads are used for this purpose. Along the vertical lines that define the corner profiles, a side board S1a, S2a, S1b, S2b can be cut off.

[0052] An example shown here is a milling head 230 with an outer and an inner machining tool 231, 232. Fig. Figure 15 shows the same log 236 during processing, with the conveying direction of the log 236 running from left to right. The two processing tools can now be inclined against the conveying direction by an angle α, the so-called tilt angle or camber. This is intended to prevent the trailing edge of the tool from recutting the already processed surface. Depending on the tool geometry, this angle can be predetermined to produce the flattest possible surface without tear-out. This angle, which is shown in Fig. 15 is exaggerated for better illustration and in practice hardly amounts to more than a few tenths of a degree, may differ for the two machining tools 231, 232.

[0053] Methods for producing sawn timber in which the milling heads according to the invention can be used are known per se. A method in which a log is first clamped on two sides, then turned and clamped on the remaining two sides, is known, for example, from the aforementioned EP 2 743 023 A1, to which reference is made in full to avoid unnecessary repetition. After clamping, the log is turned back and a first corner area is milled out in a cutter, and a side board is cut off on each side in a saw in a preliminary cut. By using milling heads according to the invention of the type described above, this method now allows two side boards of individually adjustable width and preferably also individually adjustable thickness to be produced on each side in a single milling step and a subsequent sawing step.

[0054] The described method involves, after the side boards are cut off in the initial cut, rotating the log back into its starting position and milling out further corner areas for side boards in the subsequent cut. The log, thus profiled, is then guided through a saw following its curvature. This saw cuts off the side boards along the milled corner areas and simultaneously divides the main log according to the previously determined cutting solution. Milling heads according to the invention can also be used in the second milling step before the final cut, allowing the production of two side boards per side in a single milling and subsequent sawing step, in addition to the main log.

[0055] Another known method is described in DE 10 2022 132 324 A1, to which full reference is also made here. The method described there does not require rotating the log, as the log is clamped vertically and horizontally using successive chippers. Subsequently, the first corner areas are milled and the first side boards are cut off in a pre-cut in the horizontal direction. Finally, a second milling of corner areas takes place, and the log is sawn into main and side boards in the vertical direction. In both cases, both for profiling the log before cutting off the pre-cut side boards and for further profiling the log before splitting into main and side boards in the post-cut, milling heads according to the invention can be used to produce two pre-cut side boards per side and two further side boards per side in the post-cut. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] EP 2 743 023 A1 [0002, 0053] DE 10 2022 132 324 A1

[0055]

Claims

[1] Milling head (10, 110) for profiling tree trunks with two rotating machining tools (12, 14; 112, 114) whose axes of rotation run parallel to each other except for any differing angles of inclination of the machining tools (12, 14; 112, 114), wherein the machining tools (12, 14; 112, 114) are designed to produce a circumferential and an end-face machining surface and the position of the circumferential machining surfaces of the two machining tools (12, 14; 112, 114) with respect to a tree trunk to be machined is adjustable independently of the other machining tool (12, 14; 112, 114). [2] Milling head (10, 100) according to claim 1, in which the two machining tools (12, 14; 112, 114) are arranged adjustable relative to each other in the direction of their axes of rotation, so that the respective position of the end face machining surfaces in relation to a tree trunk (206) to be machined is also adjustable independently of the other machining tool (12, 14; 112, 114). [3] Milling head (10) according to claim 1 or 2, wherein a first of the machining tools (12) are mounted directly and the second machining tool (14) is mounted via an eccentric (24) on a common tool carrier (22), and wherein the position of the circumferential machining surface of the first machining tool (12) in relation to a tree trunk to be machined is adjustable by adjusting the tool carrier (22) and the position of the circumferential machining surface of the second machining tool (14) in relation to the tree trunk to be machined is adjustable by rotating the eccentric (24) or the tool carrier (22). [4] Milling head (10) according to claim 3, wherein the rotary drive of the two machining tools (12, 14) is provided via a common drive unit (20) and the machining tools (12, 14) are rotaryally coupled to each other via a gearbox (40) housed within the eccentric (24). [5] Milling head (100) according to claim 1 or 2, wherein the two machining tools (112, 114) are mounted on separate tool carriers (122, 130), and the position of the circumferential machining surface of each of the two machining tools (112, 114) in relation to a tree trunk to be machined is adjustable by adjusting the associated tool carrier (122, 130). [6] Milling head (100) according to claim 5, wherein the rotary drive of the two machining tools (12, 14) is provided via a common drive unit (124) and the machining tools (112, 114) are rotaryally coupled to each other via a cardan shaft (148). [7] Milling head (10, 100) according to one of the preceding claims, wherein the rotary drive of the two machining tools (12, 14; 112, 114) is synchronized, wherein the machining tools (12, 14; 112, 114) are each divided into tool segments (12a, 12b, 12c, 14a, 14b, 14c; 112a, 112b, 112c, 114a, 114b, 114c) and the tool segments (12a, 12b, 12c, 14a, 14b, 14c; 112a, 112b, 112c, 114a, 114b, 114c) of the two machining tools (12, 14; 112, 114) are mutually comb. [8] Milling head (10, 100) according to claim 7, wherein the angular velocities of the two machining tools (12, 14; 112, 114) are inversely proportional to the number of tool segments (12a, 12b, 12c, 14a, 14b, 14c; 112a, 112b, 112c, 114a, 114b, 114c) per machining tool (12, 14; 112, 114). [9] Milling head (10, 100) according to one of the preceding claims, wherein the two machining tools (12, 14; 112, 114) have different diameters and the axis of rotation of the second, smaller diameter machining tool (14; 114) is located within the cross-sectional area of ​​the first, larger diameter machining tool (12; 112) and is offset from its axis of rotation. [10] Milling head (10, 100) according to one of the preceding claims, wherein the tool segments (12a, 12b, 12c, 14a, 14b, 14c; 112a, 112b, 112c, 114a, 114b, 114c) of the two machining tools (12, 14; 112, 114) each comprise at least one circumferentially arranged chopping knife (13a, 15a) and one end-arranged circular saw segment (13b, 15b). [11] Milling head (10, 100) according to claim 8, wherein the tool segments (12a, 12b, 12c, 14a, 14b, 14c; 112a, 112b, 112c, 114a, 114b, 114c) of the machining tools (12a, 12b, 12c, 14a, 14b, 14c; 112a, 112b, 112c, 114a, 114b, 114c) have two or more chopping knives (13a, 15a) arranged offset in the radial and axial directions, the cutting areas of which overlap or at least adjoin each other. [12] A method for producing sawn timber (S1a, S2a, S1b, S2b) from a tree trunk (206, 226, 236), wherein the tree trunk (206, 226, 236) is first clamped on all four sides, then corner areas are milled out, and side boards (S1a, S2a, S1b, S2b) bounded by the milled corner areas are cut off by means of a saw, wherein in the milling step, stepped corner areas are milled out using milling heads (10, 100; 200, 220, 230) according to one of the preceding claims, and in the sawing step, two side boards (S1a, S2a, S1b, S2b) bounded by the stepped corner areas are cut off on each side of the tree trunk (206, 226, 236), and wherein for each tree trunk (206, 226, 236) the position of at least the circumferential processing surfaces (207, 208) of the two processing tools (12, 14; 112, 114; 201, 202; 231, 232) in relation to the tree trunk to be processed (206, 226, 236) independently of the other processing tool (12, 14; 112, 114; 201, 202;231, 232) is discontinued.; [13] Method according to claim 12, wherein the log (206, 226, 236) is optically measured three-dimensionally before and / or after machining and an optimized cutting solution is determined on the basis of the measurement data, which includes the side boards (S1a, S2a, S1b, S2b), and wherein the position of the circumferential machining surfaces of the milling heads (10, 100; 200, 220, 230) is adjusted to the dimensions determined for the side boards (S1a, S2a, S1b, S2b) in the cutting solution. [14] Method according to claim 13, wherein the log (206, 226, 236) is guided through the saw following its curvature by means of adjustable transport and guide rollers and the milling heads (10, 100; 200, 220, 230) are guided along during the passage of the log (206, 226, 236) in such a way that the resulting milling contour corresponds to the course of the side boards (S1a, S2a, S1b, S2b) determined within the framework of the cutting solution. [15] Method according to any one of claims 12 to 14, wherein the milling step is carried out either before cutting off side boards in the pre-cut, or before cutting the log into main and side products in the post-cut, or successively in both cases.

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