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Title:
DEBARKING ARRANGEMENT FOR A WOOD-HANDLING DEVICE
Document Type and Number:
WIPO Patent Application WO/2007/085696
Kind Code:
A1
Abstract:
The present invention relates to debarking arrangement (10) in a wood- handling device (1). Such a debarking arrangement is particularly applicable to be used in a harvester head of a forestry machine. The debarking arrangement thus comprises a member (13) arranged in the wood-handling device, extending to the surface (11) of a trunk (2) guided therein and arranged to cut bark (12) of the trunk. The member is arranged to leave on the bark of the trunk a cutting trace that is at angle (α) relative to the longitudinal axis (9) of trunk. With the debarking arrangement, this angle (α) is arrangeable to substantially correspond to the directional angle of the motion vector generated on the trunk surface (11) by the translation and rotation of the trunk.

Inventors:
HOTTI EERO (FI)
UDD JARMO (FI)
Application Number:
PCT/FI2007/050034
Publication Date:
August 02, 2007
Filing Date:
January 23, 2007
Export Citation:
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Assignee:
PONSSE OYJ (FI)
HOTTI EERO (FI)
UDD JARMO (FI)
International Classes:
B27L1/10
Domestic Patent References:
WO1992013686A11992-08-20
Foreign References:
US2891588A1959-06-23
US2830630A1958-04-15
Attorney, Agent or Firm:
KOLSTER OY AB (P.O. Box 148, Helsinki, FI)
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Claims:

CLAIMS

1. A debarking arrangement (10) for a wood-handling device (1) having feed means (6), whereby the debarking arrangement comprises a member (13) arranged in the wood-handling device, extending to the surface (11) of a trunk (2) guided therein and arranged to cut bark (12) of the trunk, characterized in that the member (13) arranged to cut bark (12) of the trunk (2) is arranged to leave on the bark of the trunk a cutting trace that is at angle (α) relative to the longitudinal axis (9) of the trunk in such a way that this angle (α) substantially corresponds to the directional angle of the motion vector generated on the trunk surface (11) by the translation and rotation of the trunk.

2. A debarking arrangement (10) according to claim 1, characterized in that the wood-handling device (1) comprises a harvester head of a forestry machine and at least feed and cutting means (4,6).

3. A debarking arrangement (10) according to claim 1 or 2, characterized in that the member (13) arranged to cut bark (12) of the trunk (2) is arranged substantially fixedly on the wood-handling device (1).

4. A debarking arrangement (10) according to claim 1 or 2, characterized in that the member (13) arranged to cut bark is arranged in the wood-handling device (1) with a joint (14) of at least one degree of freedom to allow the member to be lifted from the surface (11 ) of the trunk (2).

5. A debarking arrangement (10) according to claim 4, characterized in that the member (13) arranged to cut bark of the trunk is arranged in the wood-handling device (1) with two joints (14, 17) of at least one degree of freedom to allow both lifting of the member from the surface (11) of the trunk (2) and turning of the member to adapt to the movement of the trunk surface.

6. A debarking arrangement (10) according to any one of the preceding claims, characterized in that the member (13) arranged to cut bark of the trunk is arranged to comprise a substantially disk-like means.

7. A debarking arrangement (10) according to claim 6, characterized in that the disk-like means (13) is arranged to be rotating relative to the surface (11 ) of the trunk (2).

8. A debarking arrangement (10) according to claim 7, characterized in that the rotation movement of the disk-like means (13) is arranged to be actively guided.

9. A debarking arrangement (10) according to claim 1 to 5, characterized in that the member (13) arranged to cut bark is arranged to comprise a substantially knife-like means.

10. A debarking arrangement (10) according to any one of the preceding claims, characterized in that there are one or more members (13) arranged to cut bark of the trunk.

11. A debarking arrangement (10) according to claim 10, characterized in that several members (13) arranged to cut bark of the trunk are attached to the same support frame (15, 16) supporting the member.

12. A debarking arrangement (10) according to any one of the preceding claims, characterized in that the debarking arrangement (10) provided with a member (13) arranged to cut bark of the trunk is arranged on a frame (3) in the wood-handling device (1 ).

13. A debarking arrangement (10) according to any one of claims 2 to 9, characterized in that the debarking arrangement (10) provided with a member (13) arranged to cut bark of the trunk is arranged on a fixed delimbing knife (8) positioned in the wood-handling device (1).

14. A debarking arrangement (10) according to any one of claims 2 to 9, characterized in that the debarking arrangement (10) provided with a member (13) arranged to cut bark of the trunk is arranged on a delimbing knife (7) positioned in the wood-handling device (1) and moving relative to it.

15. A debarking arrangement (10) according to any one of the preceding claims, characterized in that when being turnable relative to the surface (11) of the trunk (2), the member (13) arranged to cut bark of the trunk comprises limiters (22, 23) for limiting the rotation movement of the member to the area that is at an angle of 25 to 55° relative to the longitudinal axis (9) of the trunk.

16. A debarking arrangement (10) according to any one of the preceding claims, characterized in that the member (13) arranged to cut bark of the trunk is arranged by means of an actuator (19) to be controlled to rise and descend relative to the surface (11 ) of the trunk (2).

17. A debarking arrangement (10) according to claim 16, characterized in that the actuator (19) comprises a pressure-medium- powered cylinder.

18. A debarking arrangement (10) according to any one of the preceding claims, characterized in that a spring member is arranged to suppress the movements of the member (13) arranged to cut bark of the trunk.

19. A debarking arrangement (10) according to any one the preceding claims, characterized in that the force directed at the bark (12) of the trunk (2) by the member (13) arranged to cut bark of the trunk is adjustable.

20. A debarking arrangement (10) according to claim 19, characterized in that the force directed at the bark (12) of the trunk (2) by the member (13) arranged to cut bark of the trunk is adjustable by means of a pressure-medium-powered actuator.

Description:

DEBARKING ARRANGEMENT FOR A WOOD-HANDLING DEVICE

BACKGROUND OF THE INVENTION

[0001] The present invention relates to a debarking arrangement according to the preamble of claim 1. Such a debarking arrangement can be utilized in moving machines, for instance in a single-grip or two-grip harvester or a harvester head of a forestry machine, as well as in stationary wood- handling machines. The primary task of the debarking system according to the invention is to contribute to the detachment of bark when a trunk is handled in a wood-handling device.

[0002] It is known as such to implement harvesting mechanically by means of forestry machines, such as harvesters and forwarders, in accordance with what is called a cut-to-length method. The harvester used in the method usually comprises at least a base capable of moving on the ground and provided with a turnable and movable lifting boom system or loader. The end of such a lifting boom system or loader carries a wood-handling device, such as a harvester head.

[0003] The harvester head used in harvesting according to the present method typically comprises means for at least cutting, felling, delimbing and measuring a trunk.

[0004] However, several harvester head structures intended particularly for different wood types, tasks or operating conditions are known. One particular example that can be mentioned in this context are special- structured feed rollers used in some harvester heads and intended for making the debarking of some wood types more efficient. The shaping of the friction surface of such feed rollers aims at facilitating the rotation of a trunk during the delimbing and debarking. On the other hand, different knife-like and claw-like cutters have been used for cutting bark in the direction of the longitudinal axis of a trunk. One such device for removing bark from the trunk under handling in a harvester head is disclosed in publication WO 92/13686.

[0005] When using such devices, it has been observed, however, that a knife-like blade which is arranged fixedly on the frame of a harvester head or, for example, on a delimbing cutter and intended for slitting bark is clogged easily, causing thus significant problems for the debarking process. Therefore, for cutting bark in the longitudinal direction, also cutting rollers arranged rotationally relative to the frame of the harvester head have

advantageously been used. Since such a rotating cutting roller arranged fixedly relative to the frame of the harvester head has a rotation axis perpendicular to the longitudinal axis of the trunk and since the aim in these debarking applications is to rotate the trunk between the feed members of the harvester head in the above manner to achieve as comprehensive an effect on the trunk surface as possible, it has been noted that the cutting roller prevents the rotation of the trunk in the harvester head or makes it more difficult. Further, a cutting roller the rotation axis of which is perpendicular to the longitudinal axis of the trunk tends to break the bark and possibly also the wood material under the bark, whereby there is a risk of the harvested timber being subjected to harvesting damages decreasing the value of the wood raw material.

BRIEF DESCRIPTION OF THE INVENTION

[0006] An object of the present invention is to provide a debarking arrangement in a wood-handling device in such a way that a completely new kind of solution could be achieved for the above problems caused by the drawbacks of the prior art. This object is achieved in such a way that the debarking arrangement has, in accordance with this invention, the characterizing features defined in the claims.

[0007] More specifically, the debarking arrangement according to the invention is primarily characterized by what is stated in the characterizing part of claim 1. Preferred embodiments of the invention are disclosed in the dependent claims.

[0008] The invention is thus based on the idea that a member arranged to cut the surface of bark in substantially the longitudinal direction is arranged in such a position relative to the longitudinal axis of the trunk that when the trunk is rotating in the wood-handling device during the wood handling, this member arranged to cut bark resists the rotation movement of the trunk as little as possible.

[0009] In one preferred embodiment of the debarking arrangement of the invention, the member arranged to cut bark is arrangeable for instance at an angle of 45° relative to the translation movement of the trunk, i.e. the displacement in the direction of the longitudinal axis of the trunk. It has been empirically proved that when being installed in this way, the member gives the rotation movement of the trunk as little resistance as possible so as not to cause damage to the wood handling or the portion under the bark.

[0010] On the other hand, it is also feasible that the member arranged to cut bark could be suspended on a frame in the wood-handling device in a turnable manner relative to at least one rotation axis. In this way, a rotation movement guided by the trunk movement is generated which preferably moves the member to such an angle relative to the longitudinal axis of the trunk which substantially corresponds to the direction of movement of the trunk surface generated by the rotation movement of the trunk in each particular case. In practice, the member arranged to cut bark follows here a substantially spiral track drawn by the observation points on the trunk surface. The member arranged to cut bark draws a spiral track on the bark, the pitch of which track depends on the displacement speed, i.e. translation, of the trunk during each particular working situation, as well as on the rotation speed, these two together generating the motion vector of an observation point.

[0011] When the member arranged to cut bark is positioned in the direction of the motion vector generated on the trunk surface and when the member resists the rotation movement of the trunk as little as possible, the need of power and/or performance caused by the use of the debarking arrangement is, at the same time, minimized. In this way, the total power and/or total performance required for wood handling can be minimized.

[0012] To minimize damages generated in the wood material of the trunk under handling, the member arranged to cut bark may also be arranged to be detachable from contact with the trunk, for example when the wood- handling device with the trunk must be reversed, or when the trunk is handled in another way at a point where the bark has already been substantially removed. By detaching the member arranged to cut bark from contact with the bark, unduly great loads are avoided, for instance when the device with the trunk must be reversed. In this way, the life span of the present debarking system can be extended.

[0013] In this way, the solution according to the invention achieves an essential aim set for the debarking, in other words that the wood material itself remains intact but the bark can still be removed as completely as possible.

[0014] Further, the rotation movement of the member arranged to cut bark according to the present debarking arrangement is arrangeable to be actively controlled, for example by means of a hydraulic engine. In this way, the cutting of the bark can be made significantly more efficient because cutting

longitudinal strands in the bark becomes easier. Cutting the strands makes the debarking more efficient and contributes, at the same time, to the breaking of the removed bark into smaller pieces that will decompose more easily and quickly. In addition, when recovered, such bark waste consisting of smaller pieces is easier to handle as well in transportation as in conveyors of a combustion plant.

[0015] A member that is movable relative to the frame of a wood- handling device can also preferably be cleaned of impurities, such as bark pieces and branches accumulated on it, by removing it from time to time from the trunk surface. To make the cleaning more efficient, the debarking system can even be provided with particular counterpart or cleaning means, whereby the member, when moving against these means, is cleaned even more efficiently.

[0016] Further, an option where the member arranged to cut bark can be moved both into and out of contact with the bark enables a wood- handling device, such a harvester head, with which also such trunks can be handled whose bark must not be removed or damaged. Since both debarking and conventional delimbing can thus be carried out with the same device, time- consuming and difficult installing operations on the wood-handling device can be avoided.

[0017] Advantages provided by the invention are also described in the following, with a more detailed explanation of particular embodiments of the invention.

BRIEF DESCRIPTION OF THE FIGURES

[0018] In the following, some embodiments of the invention are described in more detail with reference to the attached drawing, in which

Figure 1 shows schematically the positioning of a member arranged to cut bark in a wood-handling device which is here represented by a harvester head of a forestry machine;

Figure 2 shows axonometrically one embodiment of the member arranged to cut bark according to Figure 1, the member being detached from the harvester head;

Figure 3 shows a front view of the member according to Figure 2, the member being detached from the trunk surface;

Figure 4 shows a front view of an alternative embodiment of the member arranged to cut bark, the member being detached from the trunk surface;

Figure 5 shows a front view of a second alternative embodiment of the member arranged to cut bark, the member being detached from the trunk surface;

Figure 6 shows a front view of a third alternative embodiment of the member arranged to cut bark, the member being detached from the trunk surface;

Figure 7 shows several disk-like cutting members attached to a support means in the debarking system;

Figure 8 shows several knife-like cutting members attached to a support means in the debarking system;

Figure 9 shows axonometrically a debarking system for forming the structure of the member arranged to cut bark and for controlling the member;

Figure 10 shows axonometrically an alternative debarking system for forming the structure of the member arranged to cut bark and particularly for controlling the member; and

Figure 11 shows axonometrically a trunk and a bark-cutting member arranged on it.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0019] In the following, some preferred embodiments of the present debarking arrangement are described with reference to the above-mentioned figures. Thus, the debarking arrangement comprises components denoted in the figures with reference numerals that correspond to those used in this description.

[0020] As noted in the introduction of this description, harvesting is conventionally implemented mechanically with various forestry machines, such as harvesters and loaders. These are not shown in the attached figures. When harvesting in accordance with a product-type method, a tree is felled and the trunk is delimbed and cut into pieces of suitable sizes. In some cases, these pieces are also debarked to facilitate the after-handling and to improve preservability.

[0021] A forestry machine used in harvesting can be provided with a particular lifting boom system or a loader, for example. This, in turn, is used for

supporting, turning and moving a wood-handling device 1, for example in the embodiment of a harvester head according to Figure 1. However, it is known to fell and delimb a tree with many different devices that are not separately shown in this context.

[0022] In some cases, it is also desirable to debark a felled and delimbed tree, in which case this can be carried out either in connection with the felling or at a separate working stage. Such debarking may be carried out as well with wood-handling devices used for felling as with other wood- handling devices arranged on a moving or stationary base.

[0023] The present debarking arrangement is here described in the context of a wood-handling device typically comprising handling means for at least cutting, felling, delimbing and measuring a trunk 2. A frame 3 in a wood- handling device according to Figure 1 thus comprises a cross-cutting saw 4, a measuring roller 5, feed rollers 6, movable delimbing knives 7 and a fixed delimbing knife 8.

[0024] When a trunk is handled in the wood-handling device 1 , both a translation movement in the direction of the longitudinal axis 9 of the trunk and a rotation movement around the longitudinal axis are usually generated. This rotation movement may be generated in the trunk as a side effect of the handling, or it may be achieved with special means in the wood-handling device.

[0025] In addition to the handling means 4 to 8, the present wood- handling device 1 is provided with a debarking arrangement 10 comprising a member 13 which extends to the surface 11 of the trunk 2 guided in the arrangement and is arranged to cut bark 12 on the trunk surface. When cutting bark, this cutting member is arranged to follow the movement generated for the trunk in the wood-handling device, whereby it leaves on the bark of the trunk a cutting trace, the pitch of which depends on the displacement speed, i.e. translation, and on the rotation speed, i.e. rotation, of the trunk during each particular working situation. To achieve such a cutting trace on the bark of the trunk, the member arranged to cut bark is particularly arranged to be at an angle relative to the longitudinal axis 9 of the trunk in such a way that such an angle α substantially corresponds to the directional angle of the motion vector of the trunk surface 11 obtained as a resultant of the translation and rotation movements of the trunk. However, the angle α can also be selected such that

it slightly deviates from the direction of the motion vector, generating thus a bark-removing force effect on the bark of the trunk.

[0026] Most preferably, the member 13 arranged to cut bark 12 of the trunk 2 is arranged substantially fixedly on the wood-handling device 1, particularly on its frame 3. Thus, the cutting member forms, relative to the longitudinal axis 9 of the trunk, a fixed angle a of 25 to 55°. In empirical tests, the magnitude of the angle has been particularly selected to be about 45°.

[0027] In this context, the member 13 arranged to cut bark being installed fixedly means primarily that the debarking arrangement 10 with its cutting member is substantially unmovable relative to the frame of the wood- handling device. It is feasible, however, to install the cutting member on the wood-handling device movably in such a way that it can be displaced in substantially the radial direction of the trunk's cross-section. Thus, the cutting member is movable on the wood-handling device relative to the trunk surface 11 , in other words the member is moved towards the trunk surface or away from it. Such movement can be implemented for instance with embodiments according to the attached figures, in which the member is connected to the wood-handling device with a joint 14 of at least one degree of freedom to enable the detachment of the member from the trunk. On the other hand, it is possible to guide the member's track of movement with a special actuator affecting the member particularly for this purpose directly or via a parallelogram arrangement known as such. Such an actuator preferably comprises a pressure-medium-powered cylinder, such as a hydraulic cylinder.

[0028] When the cutting member 13 in the debarking arrangement 10 is movable in substantially the radial direction of the trunk's 2 cross-section, also the force that is directed at the bark 12 of the trunk by the member can preferably be arranged adjustable. Thus, the force is preferably adjustable by means of a pressure-medium-powered actuator, whereby for example an actuator guiding the radial movement of the trunk in the cutting member can be used as the actuator.

[0029] To adjust the track of movement of the member 13 arranged to cut bark of the trunk 2 as desired, for example to correspond more accurately to the real track of movement of the trunk surface 11 , the cutting member can be also arranged in the wood-handling device with an arrangement comprised of more than one joints or with joints of more degrees of freedom in accordance with Figures 2, 3 and 5. This enables both moving of

the member in substantially the radial direction of the trunk and the turning of the member to adapt to the rotation movement of the trunk.

[0030] One guiding joint and actuator arrangement of the member 13 arranged to cut bark 12 of the trunk 2 is illustrated in Figure 9. This figure shows a cutting member arranged preferably rotatingly at the end of a cutting arm 15. Such a cutting arm is attached to a swivelling shaft 16 with a joint 17 of at least one degree of freedom. The swivelling shaft has a rotation movement relative to the joint 14, whereby the cutting member is controllable relative to the surface 11 of the trunk under handling in the wood-handiing device. By means of swivelling movement of the cutting arm, the cutting member is, in turn, guidabie to different angles relative to the longitudinal axis of the trunk. In the embodiment according to the figure, the controlling of the swivelling shaft is implemented with an actuator 19 operating a swivelling rod 18 attached to the swivelling shaft. However, the control can also be implemented in other manners known as such to persons skilled in the art.

[0031] In the attached figures, at least two different embodiments are presented for the cutting member 13 arranged to cut bark of a trunk. Thus, Figures 1 to 4 and 9 as well as 10 show a member arranged to comprise a substantially disk-like means. Such a disk-like means is preferably arranged rotatingly on a support frame supporting it, and it is thus rotating relative to the trunk surface. For example in Figure 9, the disk-like means is attached to the cutting arm 15 via a connecting shaft 20. However, there is nothing to prevent the disk-like means from being attached to its support frame substantially rigidly.

[0032] Having such a disk-like shape, the cutting member 13 is also arrangeabie to be actively controllable in such a way that a rotation movement relative to the cutting arm 15 is generated in the means, for example with a hydraulic engine. Such an active movement of the cutting member contributes to the cutting of bark for instance by cutting the longitudinal strands of the bark. The rotation speed of the disk-like means can thus be adjusted, and the shape of its outer periphery can be selected to cut or even saw bark more efficiently.

[0033] On the other hand, Figures 5 and 6 show a cutting member 13, which is arranged to comprise a substantially knife-like means. The cutting member according to Figure 5 is arranged to be turnable relative to its swivelling shaft 16 forming the support frame, while a cutting member presented in Figure 6 is arranged substantially rigidly on its swivelling shaft,

[0034] Although the cutting member 13 is, for instance in the embodiment of Figure 9, arranged to be substantially freely turnable, following the movements of the surface 11 of the trunk 2, it is naturally also possible to turn it actively. Such an embodiment is shown in Figure 10, in which an actuator 21 - in this case a hydraulic cylinder - is arranged to guide the angle α of the cutting member relative to the trunk surface.

[0035] in the attached figures, only such embodiments are illustrated that comprise only one member 13 arranged to cut bark. However, it is completely feasible that there would be more than one debarking arrangement 10 in the wood-handling device or more than one cutting member in the debarking arrangement. In such a case, the members may be arranged on the same connecting shaft 20 in accordance with Figure 7 or on different connecting axes. Different connecting axes in the debarking arrangement 10 may also have a different number of cutting members. Also, one or more fixed blades may be arranged on the same support frame in accordance with Figure 8.

[0036] Instead of being attached to the frame 3 of the wood- handling device, the member 13 arranged to cut bark 12 of the trunk 2 is arrangeable on a fixed debarking knife 8 or on a debarking knife 7 movable relative to the frame in the wood-handling device.

[0037] When arranged to be rotating relative to the longitudinal axis 9 of the trunk 2, the member 13 arranged to cut bark preferably comprises limiters to limit the rotation movement of the member to the area that is, as mentioned above, at an angle of 25 to 55°, for example, relative to the longitudinal axis of the trunk. Such limiters comprise for instance mechanical blocks to limit the movements of the cutting arm 15 in the joint 17. Such an embodiment of limiters can be seen in Figure 9, in which a pin 23 arranged in a slot 22 defines the extreme limits of the cutting arm movements.

[0038] The movement of the member 13 arranged to cut bark 12 of the trunk 2 may also be guided or suppressed by a spring member in a manner known as such. Also the use of a pressure-medium-powered actuator together with a spring member is feasible in this case.

[0039] It will be obvious to a person skilled in the art that with the advance of technology, the basic idea of the above method and a debarking arrangement implementing it may carried out in a plurality of ways. The

solution disclosed and its embodiments are thus not restricted to the above examples but may vary within the scope of the claims.