AU2007201892A1 - Method and an apparatus for debarking a tree trunk and a debarking member - Google Patents

Description

m AUSTRALIA PATENTS ACT 1990 SCOMPLETE SPECIFICATION 00 SNAME OF APPLICANT(S):: SWaratah OM Oy ADDRESS FOR SERVICE: DAVIES COLLISON CAVE Patent Attorneys 255 Elizabeth Street, Sydney, New South Wales, Australia, 2000 INVENTION TITLE: Method and an apparatus for debarking a tree trunk and a debarking member The following statement is a full description of this invention, including the best method of performing it known to me/us:- 5102 C METHOD AND AN APPARATUS FOR DEBARKING A TREE TRUNK AND A DEBARKING MEMBER Cc Field of the invention C The invention relates to an apparatus for delimbing and oO debarking of tree trunks. The invention also relates to a debarking member 00 which is applied in the delimbing and debarking apparatus. Furthermore, the cinvention relates to a method in an apparatus for delimbing and debarking of tree trunks.

Background of the invention For the manipulation of tree trunks, a harvester head is used, whose purpose is to grip an upright growing tree, to cut the tree and to fell it.

After this, the harvester head delimbs the tree trunk and cuts it into pieces of fixed length. The harvester head is normally mounted by joints at the end of the boom assembly of a forest machine. The working machine is particularly a harvester which moves on a terrain by means of wheels or a crawler. Some harvester heads are used for the loading of the trunk in forwarders which are also used as harvesters, wherein they are also provided with grapple members turnable with respect to the frame structure pairwise on different sides of the trunk. The grapple may also consist of blade members for delimbing.

A harvester head is disclosed in US 6,318,425 B1. The harvester head comprises the necessary actuators, normally hydraulic cylinders and hydraulic motors which can be used to control the position and the different functions of the harvester head. Another harvester head is disclosed in WO 2005/020669 Al. A forest machine with a harvester head mounted at the end of the boom assembly is disclosed in WO 03/096794 Al.

The harvester head, which is also called a delimbing apparatus or a manipulating apparatus for tree trunks, is normally provided with at least upper delimbing members which are pivotable in relation to the frame structure. The delimbing members are normally placed as a pair on different sides of the tree trunk. The delimbing members comprise delimbing blades for cutting off the branches while the trunk is being supported and fed through the apparatus. The harvester head may also comprise another, lower O 2

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N pair of delimbing members or a single delimbing member. The feeding members normally comprise a feed roll or a feed pulley which is pressed against the trunk and pulls it past the delimbing members and through the Capparatus. The feeding members are normally arranged as a pair on opposite sides of the tree trunk. The head is also provided with cutting Nmembers, such as a chain saw, for performing the cutting of the tree trunk for C felling, and sawing it into pieces of fixed length.

00 Of the different wood species, the harvester heads are used N particularly for the delimbing and cutting of pine and spruce, but also for the delimbing and cutting of hardwood and different eucalyptus species. Some N harvester heads are also capable of debarking the trunk of the eucalyptus species while it is being processed at the harvester head.

One debarking harvester head is disclosed in US 5,957,177, wherein the feed rolls are equipped with a cutting pattern for detaching the bark from the tree trunk. During the feeding, the tree trunk can also be rotated around its longitudinal axis to detach the bark more efficiently from all sides of the tree trunk. The feed rolls are placed both in the frame of the harvester head and inside the swivelled arms.

Another debarking apparatus is disclosed in US 3,941,174, wherein the frame comprises a movable chain acting as the feeding member and transferring the tree trunk through the apparatus. The delimbing blades and the debarking blades are provided in a chain-like member which is pressed around the tree trunk. When the tree trunk passes through the apparatus for delimbing, it is simultaneously debarked.

However, with the apparatuses of prior art it is not possible to achieve both good debarking and efficient delimbing. In an apparatus which is very applicable and durable in use, the technology known from harvester heads is applied for performing the delimbing, applying delimbing blades which can be swivelled in a controlled manner. Furthermore, debarking is performed by applying debarking members, for example debarking spikes or blades, provided on the surface of the feed rolls to remove the bark.

However, a problem with the feed rolls may be their insufficient capability to remove the bark from the tree trunk. A limiting factor to be considered in the construction of the rolls is the fact that the debarking spikes or blades should not cause unnecessary damage to the wood underneath the bark.

By a concave design of the debarking rolls, the round shape of the tree trunk can be taken into account. However, the diameters of tree N trunks vary to a great extent, wherein the contact between the roll and the tree trunk is always point-like, as in US 5,957,177, in which the rotation axis of the roll and the longitudinal axis of the trunk are across each other. The contact is very short even though the roll were concave. Due to the insufficient contact, the bark is removed from a narrow area only and the peeling of the bark becomes more difficult. It would be possible to increase the number of cutting rolls, but they would increase the weight and, 00 moreover, they are difficult to install and maintain in the frame of the N harvester head.

Summary of the invention It is an aim of the present invention to eliminate the abovepresented drawbacks and to make debarking more efficient. By using a stationary debarking surface forming an abrasive contact with the tree trunk, a more efficient result is obtained than by using a contact based on rolling.

The apparatus for delimbing and debarking of tree trunks according to the invention will be presented in claim 1. The debarking member for the delimbing and debarking apparatus according to the invention will be presented in claim 10. The method in the apparatus for delimbing and debarking of tree trunks according to the invention will be presented in claim 14.

In one embodiment of the invention, a planar debarking member is applied in the harvester head, against which member the tree trunk is placed in contact, which is of an elongated, substantially linear type and is substantially parallel to the longitudinal axis of the tree trunk. Thanks to the use of the friction surface, the contact between the debarking member, that is, the debarking friction surface or debarking supporting surface, and the tree trunk can be increased significantly when compared with rolls of prior art.

By mounting the debarking surface to the frame structure of the harvester head, the debarking member can be made very stable and durable.

Furthermore, the debarking member and simultaneously the contact can be simply extended as long as possible by extending the debarking member in the direction of the frame structure.

In one embodiment of the invention, the feeding members also apply cutting and debarking members, particularly feed pulleys equipped with cutting and debarking members.

N A particular advantage is the more efficient peeling of the bark, thanks to the longer contact, because the contact between the tree trunk and the debarking surface does not involve rolling but abrasion. In the debarking surface, various debarking spikes and blades are applied, whose more detailed configuration varies according to the need and the desired result.

Using a particularly long structure gives the advantage that a maximally large part of the shell surface of the tree trunk is processed by the 00 debarking surface, wherein the peeling of the bark becomes more efficient.

N The length of the debarking surface and the rotation of the tree trunk are fitted so that the shell surface of the tree trunk is processed at least once by N the debarking surface. The debarking surface will process the tree trunk in a spiral manner.

The planar surface can be easily and quickly replaced with a new one or a surface of another type as needed. The fixing to the harvester head is simple, and the provision of the plate structure with various debarking spikes and blades is simple when compared with, for example, a circular roll.

Another particular advantage is the fact that the bark can be collected more efficiently at the harvester head, close to the debarking surface, wherein the processing of the bark is controlled better. The bark is accumulated in front of the linear contact, primarily between the harvester head and the tree trunk.

The use of the debarking surface has the advantage that the surface can extend as low as possible in the harvester head, all the way down to the cross-cutting saw, wherein the debarking of the tree trunk to be processed begins as close as possible to the cutting point at the butt end of the trunk and the need to move the tree trunk back and forth at the harvester head because of the debarking is reduced.

Thanks to the combined effect of the debarking surface and the debarking feed rolls, efficient cutting and peeling of the bark are achieved.

The feed rolls slit the bark in pieces, forming partly elongated strips, and the members of the debarking surface cut the strip to shorter lengths which are easily removed from the tree trunk.

Brief description of the drawinqs In the following description, the invention will be illustrated with reference to the appended drawings.

C Figure 1 shows a harvester head for debarking a tree trunk i according to one embodiment of the invention.

Figure 2 shows an embodiment of the debarking member C) applied at the harvester head of Fig. 1, seen from the front.

Figure 3 shows the debarking member of Fig. 2 seen in a N diagonal direction.

00 Detailed description of the invention Figure 1 shows an apparatus 1 which is an apparatus for N delimbing and debarking of tree trunks, wherein a frame structure or a frame 2 is shown, which is placed on top of a tree trunk to be processed and to which the mounting arms 5 of the feeding members 3 and 4 are coupled by joints 6. In this embodiment, the feeding member comprises a cylindrical roll rotatable by means of a motor 7. Two feeding members are provided, one on each side of the tree trunk. The rotating axes of the feeding members 3, 4 are either oblique or perpendicular to the longitudinal direction X. The trunk is carried and pressed against the frame 2. The trunk is movable in its longitudinal direction X which is vertical and parallel to the frame 2 in Fig. 1. It is also possible to arrange that the mounting arm is mounted to the frame structure by a joint whose swivelling axis is substantially parallel to the longitudinal direction X. An actuator 8, in this case a cylinder, is coupled between the mounting arms 5 to take care of the rotational position and the compressive force of the feeding members 3 and 4. Two cylinders can also be used which are coupled between the frame structure 2 and the mounting arms The apparatus 1 also comprises a curved grapple member 9 combined with a delimbing blade and having a rotation axis substantially parallel to the longitudinal direction X. On the opposite side of the trunk, another curved grapple member 10 is provided as a pair to the grapple member 9, also combined with a delimbing blade. The grapple members 9, are used to grip the trunk, to support the trunk and to delimb the trunk when the trunk is fed in the direction X by the feeding members 3, 4 through the apparatus 1. Thus, the grapple members 9, 10 with their delimbing blades form the necessary pair of delimbing members for the delimbing. The feeding members 3, 4 are cylindrical in shape, and their outer shell is equipped with members 25 and 26 and a pattern for the purpose of N penetrating through the bark, gripping the trunk for feeding and also causing the rotation of the trunk around the direction X. The cutting contributes to the debarking which is finished by means of the surface 11. In this case, the 0 pattern comprises several adjacent ridges arranged in a spiral shape and having sharp apices, and also spikes provided between the ridges to grip the trunk.

In one embodiment of the invention, the feeding members 3, 4 00 not equipped with debarking or cutting members, but the function of the feeding members is solely to feed and rotate the tree trunk. Instead of rolls, 0 10 the feeding members can also be equipped with a crawler which is, for Sexample, an endless band or chain wound around two rolls.

For delimbing of the upper surface of the trunk, the apparatus also comprises a curved delimbing blade 24 which is normally movable and is pressed against the trunk, for example by means of a spring.

The apparatus 1 is in the position shown in Fig. 1 when the apparatus 1 is used to grip a substantially vertical trunk, wherein the grapple members 9, 10 and the feeding members 3, 4 are open and the trunk is placed against the supporting surfaces of the frame 2. In this embodiment, the debarking surface 11 is also used as a supporting surface, being a planar metal sheet fixed to the frame 2, substantially vertical in the position of Fig. 1.

Simultaneously, the debarking surface 11 performs debarking of the trunk, for which purpose the surface 11 is provided with short ridges with sharp apices in different directions. Alternatively or additionally, spikes or blades can be used for cutting the bark. In particular, the means elevated from the surface 11 supplement the function of the feed rolls 3, 4 and debark the trunk, simultaneously cutting and cross-cutting the bark. The height of the means or the ridge is selected to correspond substantially to the thickness of the bark, for example 10 to 15 mm. When rotated, the trunk is chafed obliquely against the surface 11.

In the embodiment of Fig. 1, the contact between the trunk and the surface 11 becomes long, and the ridges cut and remove the bark from a great length in the longitudinal direction X of the trunk. The surface 11 is placed centrally in the frame 2, at a location where the trunk is supported against the frame 2.

The apparatus 1 also comprises a cross-cutting device 12 for cutting off the trunk. The cross-cutting device 12 is normally a chain saw equipped with a pivotable guide bar. The cross-cutting device 12 performs N the cross-cutting of the trunk to pieces of fixed length when it is carried in the horizontal direction. The chain saw is placed in a saw box 13.

The frame 2 can be rotated 90 degrees with respect to the position of Fig. 1, to a horizontal position, by joints 14 around a horizontal rotation axis. The joints 14 connect the frame 12 to a swivelling arm 15 which N is suspended at the end of the boom assembly of the forest machine by 0means of mounting and rotating members, for example a rotating device 16 and a support 17.

c- In one embodiment of the invention, the apparatus 1 is not equipped with the swivelling arm 15 but it is permanently horizontal. The frame of the apparatus is suspended at the end of the boom assembly, for example, by means of the rotating device and the support. The apparatus according to said embodiment is used for gripping a cut tree trunk lying on the ground, and for delimbing and debarking. The invention can also be applied in an apparatus which is mounted on a mobile platform, for example in a forest machine, and to which the tree trunks to be processed are lifted by means of a grapple.

Furthermore, the apparatus 1 comprises a lower pair of grapple members 18 and 19, which are preferably provided with delimbing blades.

The grapple members 18, 19 support the trunk and secure the placement of the trunk against the surface 11. Also the feeding members 3, 4 and the grapple members 9, 10 keep the trunk in their grip and against the frame 2.

The grapple members 18, 19 are lower than the grapple members 9, when seen in the vertical position of the apparatus 1 in Fig. 1, wherein the saw box 13 is on the same butt end side of the trunk. In addition to the surface 11, the frame 2 also comprises other supporting surfaces, which may also comprise a measuring pulley for length measurement.

The surface 11 is placed between the lower grapple members 18, 19, from where it extends all the way down to the saw box 13, as close as possible to the opening in the saw box where the chain saw comes out.

Upwards, the surface 11 extends up to the plane extending through the rotation axes of the feeding members 3, 4 and being parallel to the direction X. Consequently, the surface 11 extends substantially to the point where the feeding members touch the tree trunk. Above the surface 11 a supporting surface 21 is placed between the upper grapple members 9, 10. The feeding members 3, 4 are placed between the upper and lower grapple members.

SThe surface 11 may be narrow, and in the presented example, its length is a five times the width, or greater.

In one embodiment of the invention, the surface 11 extends as Shigh as possible, up to the delimbing blade 24, to achieve particularly efficient debarking.

C An applicable embodiment of the surface 11 is shown in more 00oo detail in Figs. 2 and 3, comprising a surface composed of one or more pieces forming a plane against which the trunk is placed. The surface 11 is straight Nat least in the direction X, to form, in principle, a linear contact with the trunk.

Preferably, the surface consists of a metal sheet which is resistant to N continuous wear. The plate is equipped with connecting members 21, by means of which it can be replaceably fixed and mounted to the frame 2, for example by bolt fastening. The width of the surface 11 conforms to variations in the width of the frame 2, if necessary.

In the embodiment of Figs. 2 and 3, ridges 22 and 23 with a sharp cutting apex are formed in or welded to the surface. The ridges 22 are parallel to the direction X and are placed on the center line Xl of the frame at a point against which the trunk is also placed in contact. The ridges 23 are perpendicular to the center line Xl, placed on or slightly off the center line Xl. In place of or in addition to the ridges, the surface 11 can be provided with blades, spikes or blunt structures elevated from the surface 11 towards the trunk.

The actuators of the delimbing and debarking apparatus 1 are controlled in a way known as such by means of a pressurized medium, and they are normally actuators driven by hydraulic oil, controlled by means of a valve control circuit known as such. In addition to this, the operation of the delimbing members 9, 10, 18, and 19 and the operation of the feed rolls 3, 4 are known as such already from apparatuses of a corresponding type which are used for delimbing only. The debarking is taken into account in the design of the shell of the feed rolls 3, 4.

In one embodiment, the apparatus comprises only one of the delimbing members 18 and 19, wherein it may be a grapple member for supporting the trunk only. The surface 11 is opposite to the grapple member, and the grapple member presses the trunk. However, one must make sure that the trunk is supported and it remains opposite to the surface 11, if the surface 11 is very narrow.

In one embodiment, the apparatus does not comprise the Sdelimbing members 18 and 19, but only the pair of delimbing members 9 and C' The invention is not restricted solely to the embodiments presented above. In the above-presented description, the invention has been C illustrated by means of some examples, but the invention can also be applied 00within the scope of the appended claims.

Throughout this specification and the claims which follow, unless the context requires otherwise the word "comprise", or variations such as "comprises" or O "comprising", will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps.

The reference in this specification to any prior publication (or information derived from it), or to any matter which is known, is not, and should not be taken as an acknowledgment or admission or any form of suggestion that that prior publication (or information derived from it) or known matter forms part of the common general knowledge in the field of endeavour to which this specification relates.

Claims (18)

1. An apparatus for delimbing and debarking of tree trunks, q comprising at least: a frame structure; c feeding members fixed to the frame structure in a rotatable 00oo manner, placed against the trunk and feeding it through the apparatus the longitudinal direction, wherein the feeding members are also arranged to rotate the trunk when it is passed through the apparatus; delimbing members, which are fixed to the frame structure c in a rotatable manner and are placed around the trunk and delimb it when the trunk is fed through the apparatus; and a debarking surface which is stationary and fixed to the frame structure and against which the trunk is placed during the delimbing and debarking, wherein the debarking surface is further equipped with members for debarking the trunk.

2. The apparatus according to claim 1, wherein the apparatus further comprises: at least one delimbing member or grapple member which is fixed to the frame structure in a rotatable manner under the delimbing members and is placed around the trunk and supports it when the trunk is fed through the apparatus, wherein said debarking surface is placed opposite to said at least one delimbing member or grapple member.

3. The apparatus according to claim 1, wherein the debarking surface extends upwards between the feeding members.

4. The apparatus according to claim 1, wherein the apparatus further comprises a delimbing blade for delimbing the upper surface of the trunk, wherein the debarking surface extends upwards up to said delimbing blade.

The apparatus according to claim 1 or 4, wherein the apparatus further comprises: a cross-cutting device for cutting the trunk, wherein said debarking surface extends down to said cross-cutting device.

6. The apparatus according to claim 1, wherein the feeding members are also equipped with members for debarking the trunk, wherein the feeding members comprise a pulley which is equipped with several adjacent spiral cutting ridges, spikes being placed therebetween.

7. The apparatus according to claim 1, wherein an elongated contact 00 is provided between the debarking surface and the trunk, which is Nparallel to the longitudinal direction of the trunk, when the trunk is placed against said debarking surface.

8. The apparatus according to claim 7, wherein the debarking surface is equipped with cutting ridges of varying directions, which are placed one after the other opposite to said elongated contact.

9. The apparatus according to claim 1, wherein the apparatus further comprises: an auxiliary frame, to which the frame structure is fixed in a swivelled manner so that the frame structure can swivel from the verti- cal position around a substantially horizontal rotation axis to a hori- zontal position; and mounting and rotating members, by means of which said auxiliary frame can be suspended at the end of the boom assembly of a forest machine, and which enable the swinging and rotation of the auxiliary frame around the vertical direction.

A debarking member for a delimbing and debarking apparatus, wherein the debarking member comprises: a sheet structure having a surface for debarking a tree trunk, equipped with members for debarking the trunk.

11. The debarking member according to claim 10, wherein the debarking surface is equipped with cutting ridges of various directions one after the other, placed on the center line in the longitudinal direction of the debarking surface, intended to be placed in contact with the trunk to be debarked. C

12. The debarking member according to claim 10 or 11, wherein the sheet structure has such a shape that an elongated contact is provided between the debarking surface and the tree trunk, being parallel with the longitudinal direction of the tree trunk and chafing the trunk against said debarking surface.

13. The debarking member according to claim 10 or 11, wherein the 00 structure is elongated, wherein its length is five times its width, or Ngreater, and the sheet structure comprises connecting members for fixing the sheet structure.

14. A method in an apparatus for delimbing and debarking tree trunks, the method comprising: holding a tree trunk in the apparatus; feeding the trunk through the apparatus, wherein the trunk is moved in its longitudinal direction and is simultaneously rotated around its longitudinal direction; delimbing the trunk simultaneously when it is fed through the apparatus; and debarking the trunk by holding it against a stationary debarking surface simultaneously when it is being fed and rotated, wherein said debarking surface is equipped with debarking members.

The method according to claim 14, wherein the method comprises: debarking the trunk also with the feeding members which simultaneously feed and rotate the trunk and which are equipped with debarking members.

16. The method according to claim 14 or 15, wherein the method comprises: maintaining an elongated contact between the trunk and said debarking surface, parallel to the longitudinal direction of the trunk.

17. An apparatus for delimbing and debarking of tree trunks as herein described with reference and as illustrated in the accompanying drawings. o 13 O

18. A debarking member for a delimbing and debarking apparatus as herein described with reference and as illustrated in the accompanying O drawings. 00 (Nq o~