The invention relates to a harvester for timber harvesting, which includes a frame to be attached to the boom of a work machine, to which frame are fitted

- a cutting device,

- a delimbing-blade arrangement, which includes one or more delimbing blades, and - a feed device equipped with rotating members for delimbing a tree using the delimbing-blade arrangement .

In addition, the invention also relates to a method for timber harvesting using the harvester.

It is a known fact that the power requirement of a harvester increases greatly when the delimbing blades hit a set of branches, especially branch whorls. In harvesters known from the prior art, a sufficiently great feed-roller power is used, to force the delimbing blades to run through the branch whorl. The power requirement is multiplied many times in the delimbing stage. The use of delimbing harvesters is therefore restricted by their relatively great power requirement.

In addition, the delimbing harvesters known from the prior art become mechanically complicated, if a bundle-tree processing functionality is implemented in them. Typically, a bundle-tree processing implementation requires additional claws. These can be used to hold trees already gathered to the harvester while additional trees are gathered to the harvester. The additional claws require their own operating device, which complicates the technical implementation of the harvester.

The invention is intended to create a delimbing harvester for timber harvesting, the power requirement of which is substantially smaller than that of the prior art and which can thus also be used with low-powered harvesters. In addition, the invention is also intended to create a corresponding method, in which the delimbing to be performed during timber harvesting can be performed using a substantially smaller power require- ment. The characteristic features of the harvester according to the invention are stated in the accompanying Claim 1. Correspondingly, the characteristic features of the method according to the invention are stated in the accompanying Claim 20.

The harvester includes pulsed-feed means, which are arranged to be activated when a resistance according to a set criterion is detected in the feed device.

In the harvester according to the invention, the delimbing functionality is divided surprisingly into two parts. The available power is divided ingeniously, in such a way that basic delimbing and problem locations interfering with it can be dealt with using a relatively small power requirement. The problem-free basic delimbing is based on a relatively fast low-power feed, which is performed using a feed device. At problem points in the delimbing, which the feed-device drive cannot cope with, a short impact with a relatively large force is directed at the delimbing location, for example a branch whorl, which when repeated one or more times allows the recom- mencement of the basic delimbing using the fast and low-power feed. Both stages, which take place at different times, permit a relatively small power requirement, so that the harvester according to the invention can also be used in work machines with a limited power output.

Through the invention, a harvester can be equipped with a relatively low-power feed device. According to one embodiment, the resistance in the passage of a tree can be detected, for example, by monitoring the operation of the feed device, for example, from an increase in the pressure of the feed device, or by an action by the operator of the harvester. According to a first embodiment, pulsed-feed means are arranged to pull the tree through the delimbing-blade arrangement. For this purpose, the harvester can include gripping members to grip the trunk of the tree and pull it through the delimbing-blade arrangement. The gripping members are 'arranged to be supported by the pulsed-feed means, relative to the frame of the harvester. The rotation movement takes place at a large radius .

According to a second embodiment, at least some of the delimbing blades are installed to be movable axially, i.e. parallel to the feed direction of the tree and they are operated by the operating device in axial direction.

According to one embodiment, the relative pulsed motion between the tree and the one or more delimbing blades can be .repeated until the feed-device drive can again transport the tree through the delimbing-blade arrangement. In the embodiment, which is based on a moving delimbing-blade arrangement, the pulsed motion can be boosted by locking the feed device, or by using mechanical gripping members to hold the tree in place. In the invention, it is possible to exploit the inertia of the mass of the harvester and the tree being delimbed. It is not even necessary to lock the feed device, because the rapid and short stroke is partly supported by the mass inertia. A compact delimbing arrangement, in which the blades delimbing the tree from different sides can rotate to overlap each other enables, for its part, the shortness of the stroke. Thus, the work edges of the blades delimbing the tree from different sides are close to each other axially.

The harvester according to the invention is eminently suited to work machines with limited power output, for example, tractors. In addition, the frame of the harvester can be made very light, which is advantageous in many ways. The other characteristic features of the invention are stated in the accompanying Claims, while other advantages achieved by the invention are referred to in greater detail in the description portion.

In the following, the invention is examined in detail with reference to the accompanying drawings, showing one embodiment of the invention, in which

Figures 1 - 4 show one embodiment of the harvester, seen from different directions, Figure 5 shows a cross-sectional side view of the harvester, Figure 6 shows a front view of the delimbing-blade arrangement when closed,

Figure 7 shows a top view of the delimbing- ^• blade-arrangement according to Figure 6,

Figures 8 and 9 show the delimbing-blade arrangement, with the blades in the tightest position,

Figure 10 - 12 show the delimbing-blade arrangement when opened wide, Figures 13 - 16 show examples of the opening angles of the delimbing-blade arrangement,

Figure 17 shows a cross-section of the delimbing-blade arrangement together with a tree being delimbed, Figure 1! shows the principle of another way to implement pulsed delimbing, and

Figures 19 - 23 show one embodiment based on the principle shown in Figure 18.

Figures 1 - 4 show a first embodiment of the harvester for timber harvesting, seen from different directions, while Figure 5 shows a vertical cross-section from the centre of the harvester. In Figure 1, the harvester is shown in an angled front view, in Figure 2 in a rear view, in Figure 3 in a bottom view, and in Figure 4 in a top view. The timber harvested by the harvester can be, for example, energy timber, fibre timber, or even logs. In particular, the harvester is suited to harvesting small trees, which are generally harvested, for example, in connection with first thinning, or when clearing out a neglected forest, because the work machine, to which the har- vester can be attached, can even have a very light construction. Small timber is typically defined as trees with a trunk diameter of, for example 40 - 300 mm, and more particularly 50 - 250 mm. Small timber can be harvested, for example, one trunk at a time, or also as bundle harvesting, in which case there can be several trunks at the same time in the harvester grab for processing.

The harvester includes a frame 10 that can be attached to the boom (not shown) of a work machine. The attachment can be made by means of a rotator, a tilting device (not shown) and an adapter piece 21. The two-arm adapter piece 21 can be pivoted to both sides of the frame 10 and permit a slightly swinging motion for it. The tilting device 34 can also be in the harvester itself (Figure 2) .

A cutting device 11, 12, a delimbing-blade arrangement 13, and a feed device 25 are fitted to the harvester's frame 10 as basic functionalities. In the case according to the embodiment, the cutting device includes two cutting blades 12 fitted to the lower part of the frame 10 and equipped with an operating device 11, at least one of which blades can be pivoted to the frame 10. According to a second embodiment, the cutting device can also be a chain saw (not shown) , pivoted to the frame 10, or the single blade 12 shown in Figures 19 - 23.

The delimbing-blade arrangement 13, which is in the upper part of the frame 10, includes one or more delimbing blades 13.1 - 13.3 arranged to form a delimbing circle, the detailed construction of which will be returned to slightly later hereinaf- ter. In this case, the feed device 25 remaining between the cutting device 11, 12 and the delimbing-blade arrangement 13 includes rotating members 14 equipped with an operating device 15, which are, in the case according to the embodiment, rollers. As such, the roller-feed device 25 can be, for example, one according to the prior art. The feed can also be based on crawler tracks, or even on a feed device implemented by hydraulic cylinders.

The following is a depiction of the joint operation of the basic functionalities when processing timber with a harvester according to the first embodiment. When trees are taken into the grip of the harvester, the cutting blades 12 and the feed rollers 14 can be in the open position, i.e. ready to receive a tree for processing by the harvester. The delimbing-blade arrangement 13 can also be in the open position, or alterna- tively also surprisingly still closed due to its special pick-up principle, which will be explained slightly later hereinafter. Once the tree has been gripped by the harvester, which has been lowered to the roots of the tree, the delimbing-blade arrangement 13 makes contact with the tree, as a result of which the blades 13.1 - 13.3 belonging to the arrangement 13 surround the tree mainly entirely from each side. The blades 13.1 - 13.3 adjust to the thickness of the trunk of the tree and remain close to the trunk 22 of the tree at the base of a branch. Next, the trunk of the tree can be cut through by means of the blades 12 moving against each other and pivoted to the frame 10 of the harvester. In connection with the cutting, the feed rollers 14 pivoted to the frame 10 can be pressed against the tree, in order to run the tree through the harvester and thus to strip it using the delimbing-blade ar- rangement 13. The compression cylinder 26 of the feed roller 14 is visible in Figure 5.

Next, the cutting blades 12 are opened and the tree, which has been felled as a result of the cutting is delimbed by running it axially through the delimbing-blade arrangement 13 by means of the feed device 25. It must be understood that the tree can then move relative to the blade arrangement 13, when the feed device 25 moves the tree, or also the blase arrangement 13 can move relative to the tree, in which can the feed device 25 moves the harvester totality itself in the axial direction of the tree. The arrangement 13 strips the branches off the tree when they pass the blades 13.1 - 13.3 of the arrangement 13. In a normal case, i.e. in basic delimbing, the traction of the feed device 25 is sufficient to move the tree through the blade arrangement 13 while simultaneously delimbing it, but in cer- tain situations the power of the feed device 25 may be insufficient. For such situations the harvester includes pulsed-feed means 19, 30, which are arranged to be activated when a resistance according to a set criterion is detected in the feed device 25, when the movement of the tree 22 essentially stops, or substantially slows, for example, due to insufficient power and/or adhesion in the feed device 25.

According to a first embodiment, at least one of- the delimbing blades 13.1 - 13.3 of the delimbing-blade arrangement 13 sur- prisingly includes pulsed-feed means 19 for delimbing ^' the tree 22. By means of the pulsed-feed means 19, the local jam in the travel of the tree can be overcome and the tree can then continue its journey through the harvester, for example, by means of the feed device 25 based on rotary movement.

According to one embodiment, a jam in the passage of the tree, i.e. the meeting of a set criterion concerning the travel of the tree through the delimbing-blade arrangement 13, can detected, for example, by detecting a resistance according to a set criterion in the feed device 25. If the feed device 25 is driven by an incompressible liquid, its flow through -the feed device 15, 25 can be monitored and the stopping of the feed device 25, or a corresponding exceptional situation can be detected, for example, by an increase in pressure or similar change in the liquid, for which at least one criterion value is set. As a result of the increase in pressure, the pulse-feed means 19 can activate and consequently create at least one axial impact movement in the delimbing-blade arrangement 13, which is directed to the point in the tree that has caused the resistance of the magnitude of the criterion set for it. In this case, the impact movement consists of a two-way movement, a powered impact directed to the tree point and the return movement of the delimbing-blade arrangement 13. Before performing the impact movement, the rotation of the feed rollers 14 can be locked, but in some cases they can even be left un- locked. In any event, the tree 22 is intended to remain mainly immobile during the use of the pulsed-feed means 19 connected to the delimbing-blade arrangement 13. The resistance can also be understood as a loss of adhesion appearing in the feed device 25, in which case the rollers 14 of the feed device 25 slip and rotate on the trunk of the tree 22 without transmitting power.

Some possible examples of points in a tree that cause resistance are branches and particularly branch whorls, for example, at points of yearly growth, especially in coniferous trees. Of course, the jamming of the travel of the tree can also be caused by a single branch or equally by a local bend in the trunk of the tree. The stropping of the movement of the tree can also be detected by the operator of the harvester, who can then activate the pulsed feed manually.

According to one embodiment, even a series of impacts can be created using the pulse-feed means 19. The impacts can be given in a sustained-fire form as long as the resistance criterion is seen / detected to be met. In other words, the blade arrangement 13 can be used to impact the branches located at the corresponding point until they are totally cut through, or their attachment to the tree is substantially weakened and the tree can again be made to move and be delimbed using only the feed-device drive. Intermediate cutting with the cutting blades 12 can also form part of the delimbing of the tree. Once the tree has been delimbed over the desired length, the delimbing-blade arrangement 13 and the feed rollers 14 are finally opened and as a result the top of the tree is free to fall out of the harvester. 5

Figures 6 - 16 shows the basic principle of the delimbing-blade arrangement 13 seen from different directions and with the blades in different positions. The delimbing-blade arrangement 13, which is arranged to move linearly in the axial direction,

10 can include a total of three delimbing blades 13.1 - 13.3. At least two of the delimbing blades 13.1, 13.3 can be rotatable horizontally relative to at least one pivot point 35, while one delimbing blade 13.2 remains between the rotatable blades 13.1, 13.3. The rotatable delimbing blades 13.1, 13.3 can be on arms

15 16 fitted to an auxiliary frame 18. The ends of the arms 16 are connected by a hydraulic cylinder 23, in order to rotate the arms 16 horizontally through a pivot point 17.1 fitted for them to the frame 10 and particularly to the auxiliary frame 18, in order to bring the tree 22 into contact with the delimbing

20 circle. The delimbing blades 13.1, 13.3 and their arms 16 also simultaneously form a loader grab.

The delimbing blades 13.1, 13.3 that turn inwards permit the tree 22 being delimbed to be gripped and picked up into the

25 delimbing circle formed by the delimbing-blade arrangement 13 when closed (Figures 7 and 8). The delimbing blades 13.1 - 13.3 are operationally arranged relative to each other in such a way that they can be used mainly to strip the tree entirely. This property is improved by the double-pivoting of the delimbing

30 blades 13.1, 13.3 to the frame 10 / auxiliary frame 18, in which the delimbing blades 13.1, 13.3 are first of all pivoted to the arms 16 driven by an operating device 23 through a pivot point 35 and then additionally to the frame/auxiliary frame 10, 18 of the harvester through the pivot point 17.1 of the arms

35 16. The pivoting that takes place through two points is very adjustable. In addition, double-pivoting using a spontaneously returning pivot 35 permits trees to be gathered into the delimbing circle formed by the delimbing blades 13.1 - 13.3, in order to perform bundle delimbing.

As can be clearly seen from Figures 6 and 9, the delimbing blades 13.1 - 13.3 are arranged at different heights relative to each other. Thus, as they rotate, they turn towards each other and overlap each other. In addition, the delimbing blades

13.1 - 13.3 are curved. On the outer surface of the rotating blade flanges 13.1, 13.3, there can be a conical stiffener, the shape of which can be clearly seen from Figures 6, 9, and 14.

The delimbing blades 13.1, 13.3 at the opposite end of the arms 16 are at different heights. This permits the blades 13.1, 13.3 to rotate to overlap each other. Thus, trees can be delimbed irrespective of their diameter, because the delimbing circle formed by the blades 13.1, 13.3 can be made surprisingly small (Figure 8) .

The rotation of the blades 13.1, 13.3 to overlap each other also permits the required pulse length S to remain surprisingly short (Figure 5) . The static blade 13.2 remaining between the blades 13.1, 13.3 has a flange-like asymmetrical construction. The asymmetry allows the rotatable blades 13.1, 13.3 to be rotated to overlap the static blade 13.2, thus making the blade pack 13 low and allowing the pulse to be surprisingly short. Figure 8 shows very clearly the overlapping of the blades 13.1 - 13.3, in which the blade 13.1 is on top of the static blade

13.2 and the blade 13.3 is under the static blade 13.2. In addition, the asymmetry of the blade 13.2 allows even a slightly slicing cut to be directed to a branch to be cut. The slanting nature of the blade 13.2 also allows the tree trunk to rotate slightly as it travels through the arrangement 13. The slight rotation of the tree trunk improves its delimbing throughout. Besides being asymmetrical, the fixed blade 13.2 can also be slightly curved in the circumferential direction of the tree (Figures 7 and 8) .

Both arms 16 are pivoted in vertical guides 17 fitted to both edges of the frame 10. The arms 16 can move axially in the guides 17 when the pulsed-feed means 19 move them, so- that the guides 17 on both sides provide the blades 13.1, 13.3 with a directionally stable motion, which is directly precisely at the base of the branch to be delimbed. Between the guides 17, there is an auxiliary frame 18 synchronizing the movement of the arms 16, to which the asymmetrical blade 13.2 arranged to move linearly is also attached. A vertical operating member 19 is fitted to the auxiliary frame 18 and to one end of the frame 10, in order to create a pulsed feed for at least one of the delimbing blades 13.1 - 13.3 fitted to the auxiliary frame 18. Only the piston rod 19' of the operating member is shown in Figure 17. Though the arms 16 in the guides are of a very light construction, they are nevertheless very durable. The arms 16 rotating horizontally can also have their own guides in the frame 10, but being in common linear guides 17 with the auxiliary frame 18, the construction remains simple.

The relative lightness of the delimbing-blade arrangement 13 relative to the harvester itself and even to the tree being delimbed makes it possible to exploit mass inertia when delimbing trees. Thus, the feed rollers 14 need not necessarily be locked at all during pulsed delimbing, though delimbing with the rollers 14 locked will ensure that the tree _. does not move axially during pulsed delimbing. Leaving the feed rollers unlocked achieves the advantage of permitting the feed-roller drive to be recommenced more rapidly.

According to one embodiment, the delimbing-blade claws 13.1,

13.3 can be pivoted to the arms 16 in such a way ^" that -they can be used to gather additional trees into the delimbing circle formed by the blades 13.1 - 13.3, as well as the trees that may be there already. For this purpose, the delimbing blades 13.1 - 13.3 can be mounted on the arms 16 in such a way that they return spontaneously to the delimbing position defined by the delimbing circle, i.e. they turn back to return by themselves. One example for implementing a self-returning enclosure and the inwardly opening of the delimbing circle 13.1, 13.3 is a spring or some elastomer. The springs 41 and stops (not shown) can be integrated, for example, in the pivots 35 at the ends of the arms 16 (Figure 7) . One end of the spring 41 can then be se- cured to the arm 16 and the other end to the pivot point 35 of the rotatable delimbing blades 13.1, 13.3.

According to another embodiment, the blades 13.1, 13.3 fitted to the ends of the arms 16 can be equipped with an opening device (not shown) . This can be used to alter the position of the blades 13.1, 13.3 relative to the rotatable arms 16 (Figure 12) . By means of the opening device, the blades 13.1, 13.2 are made to rotate to separate even more from each other and, on the other hand, also to close.

The circumferential frame 10 of the harvester can be formed of a tubular framework. Thus, the harvester is made relatively light, which will release machine power, for example, for the drive of the feed rollers 14. In addition, thanks to the light frame 10 such a great supporting capacity will not be required of the boom of the work machine. The tubular frame allows the weight of the frame 10 to be as little as only a few tens of kilograms .

According to one embodiment, the delimbing-blade arrangement 13 can also include members 36 for performing bundle processing and delimbing. According to one embodiment, such a member 36 can be at least one wedge-like member, which divides the delimbing circle delimited by the delimbing blades 13.1 - 13.3 for the bundle processing of trees. If necessary, the member 36 can be retracted behind the blade 13.2 fitted to the auxiliary frame 18, between the attachment flanges 20 of the auxiliary frame 18 (Figure 11), or then it can be rotated out of the way by a spring loading (Figure 17, reference number 24), as shown by the cross-section of Figure 17. By means of a single wedge-like member 36, two trees at a time can be delimbed while with two members up to four trees can be delimbed at one time. Naturally, this will halve the time taken to process each trunk. The member 36 can be part of the pulsed feed, or it can also lack pulsing. Figure 8 shows an embodiment, in which the member 36 divides the delimbing circle formed by the blades 13.1 - 13.3 clearly into two parts.

The cross-section in Figure 5 shows an example of the. definition of the length of the pulse. The length S of the stroke of the delimbing-blade arrangement 13 can, according to one embodiment, be determined on the basis of the distance H between the cutting edges of the rotatable blades 13.1, 13.2 and the maximum branch thickness of the trees intended to be delimbed by the harvester, being particularly the sum of these two factors. More particularly, the distance H refers to the distance from the cutting edge of the blade 13.3 in the lowest position to the cutting edge of the blade 13.1 in the upper position. In this case, the cutting edges of the blades 13.1, 13.3 their upper edges. One example of the stroke is 5 - 250 mm, and even more particularly 40 - 150 mm. In other words, the stroke is substantially shorter than the stroke of pulsed-feed harvesters known from the prior art, in which the tree is moved through the harvester by a pulsed feed. The closing of the blades 13.1, 13.3 to overlap each other makes them low in height and thus the length of the pulse S remains surprisingly short. The thickness of the branch depends, of course, on the tree being delimbed, but on average it can be 20 - 100 mm, more particularly 20 - 60 mm. In any event, the length S of the pulse is arranged to be such that with a single stroke it is possible to cut through all the branches in a branch whorl. The pulse length that remains relatively short accelerates the processing of the trunks.

Placing the delimbing blades 13.1, 13.3, which are fitted to 5 the arms 16, at different heights in the arrangement 13 while, in addition, pivoting them to the arms 16 also helps to allow the bundle processing of trees, based on a surprisingly simple construction. When gathering additional trees 22 into the delimbing circle formed by the blade arrangement 13, the

10 delimbing blades 13.1, 13.3 equipped with pivots can be closed when approaching the tree 22. When the trunk 22 of the still standing tree is pressed against the delimbing blades 13.1, 13.3, at the same time opening the delimbing circle slightly using the arms 16, the blades 13.1, 13.3 of the closed system

15 13 rotate in the pivot 35 of the arms 16, as shown in Figure 7, as they open, towards the delimbing circle, i.e. inwards (arrow) . The spring-loaded pivoting 35 of the blades 13.1, 13.3 then permits the delimbing blades 13.1, 13.3 to slide from in front of the tree 22 and the tree can enter the delimbing

20 circle surrounded by the blades 13.1 - 13.3. In other words, the trunk 22 of the tree is used to load the return spring 41 fitted to the pivot 35 of the delimbing blades 13.1, 13.3, which gives way and allows the tree 22 to enter the delimbing circle when the arms 16 open.

25

Once the tree 22 has passed the point of the inwardly-turned blade 13.1, the return spring 41 fitted to the pivot 35 causes the blade 13.1 to return to the delimbing position shown in Figure 7. In other words, the operating principle of a spring

30 catch can surprisingly be applied to the behaviour of the blades 13.1. At the same time, the opened arms 16 are also turned towards each other, by means of which the delimbing circle is closed and a tight delimbing circle is ensured by a grab formed around the tree by the arms 16 and the blades 13.1,

35 13.3. As the delimbing blades 13.1, 13.3 open inwards according to the arrow in Figure 7, the trees that may already be inside the delimbing circle formed by the blades 13.1, 13.3 cannot escape. This substantially simplifies the construction of the harvester, because the bundle processing property can be implemented without additional claws and the operating devices and mechanisms they require.

What is particularly surprising in the operating procedure described above is that the tree 22 can now be approached with the closed delimbing-blade arrangement 13 while the pivoting 35 that returns the blades 13.1, 13.3 permits the delimbing blades 13.1, 13.3 to move out of the road of trees 22 being gathered. This is revolutionary relative to the known solutions of the prior art, in which the tree is grabbed into the delimbing circle with the delimbing-blade arrangement open as it ap- proaches the tree. One advantage of the arrangement is that the trees that may be already in the delimbing circle are more certain to remain inside it.

It should be noted that this a dd i t i o n a 1 - c 1 a w 1 e s s bundle-processing implementation of the delimbing blades 13 can be applied in all harvesters, and is thus in no way restricted to the special roller-feed-pulsed-delimbing application described as an individual embodiment in the present application. Thus, when loaded, the delimbing blades 13.1, 13.3, which rotate inwardly and are pivoted on the arm 16 to return, can permit a tree 22 to enter the delimbing circle formed by the delimbing blades 13.1 - 13.3, 36, if the tree 22 is pressed against the delimbing blades 13.1, 13.3 and at the same time the arms 16 are opened slightly. In other words, the arms 16 and the blades 13.1, 13.3 fitted to them are arranged to permit the tree 22 to enter the delimbing circle formed by the delimbing blades 13.1 - 13.3, 36, if the tree 22 is arranged to be pressed against the delimbing blades 13.1, 13.3 by opening the arms 16 slightly, and then to return spontaneously to the basic position defined by the delimbing circle. Figures 19 - 23 show a second embodiment of the harvester for performing pulsed delimbing, in which the delimbing of branches is boosted by a relatively short linear pulse in a drive based on a rotating motion. The rough operating principle of the embodiment is shown in the schematic Figure 18. The embodiment can be implemented either together with the pulse arranged in the delimbing-blade arrangement 13 described above, or else by itself. In that case, the delimbing-blade arrangement 13 can essentially linearly immobile in the frame 10 and thus very simple, because the linear-motion guides 17, the auxiliary frame 18, and the cylinder 19 attached to it are omitted from the construction.

According to the embodiment shown in Figure 18, the pulsed-feed means 30 can be used to pull a tree 22 through the delimbing-blade arrangement 13. The traction takes place surprisingly from the opposite side of the feed device 25 to the delimbing-blade arrangement 13. In terms of forces this embodiment provides advantages over the embodiment shown in Figures 1 - 17, because now the pulse cylinder 30 can be arranged closer to the tree 22 being delimbed and the edge of the frame 10 of the harvester guiding the travel of the tree 22. One way to pull the tree 22 through the delimbing-blade arrangement 13 is to arrange gripping members 31.1, 31.2 in the harvester. The gripping members 31.1, 31.2 can surprisingly be rotated relative to the frame 10 of the harvester by the pulsed-feed means 30. The rotation movement is a rotatory movement with a wide radius .

In the base according to the embodiment, a rotation frame 33 is pivoted at one end 37 to the frame 10, in the lower part of the harvester, i.e. on the opposite of the delimbing-blade arrangement 13 relative to the feed rollers 14. In order to perform the rotation movement of the frame 10 with a wide radius, a ^Λ tail' 38 is fitted to the main frame 10 of the -harvester . At the opposite end of the rotation frame 33 to the pivot point 37, 39, horizontally rotating gripping members 31.1, 31.2, which can move towards or away from each other, are pivoted to the frame 33. The gripping members 31.1, 31.2 are arranged as a compact package, being in connection with the cutting device 5 11, 12. On the other hand, the blade 12 too can act as a gripping member. In this case, the cutting device 11 consists of only a single rotating knife blade 12. The rotating frame 33 can be formed of an open and hollow box-type structure, which provides a protected space 32 for the gripping claws 31.1, 10 31.2, the blade 12, and their rotation pivots and operating devices (not shown) .

In the feed-device drive, the rotation frame 33 shown in Figure 18 is in a horizontal position that follows the lower part of

15 the harvester frame (unbroken line) . When pulsed delimbing is activated, the piston rod of the cylinder 30 pushes the frame 33, causing it to rotate around the transverse pivot point 37 relative to the direction of travel of the tree 22 and moves to the position shown by the broken line and the reference number

20 33'. After this, the piston rod of the cylinder 30 returns the frame to the position shown by the reference number 33; When it is in the extreme position shown by the reference number 33', the grip of the grab claws 31.1, 31.2 on the tree 22 can be slackened and thus the tree 22 can be made to move over the

25 problem location. This has the important advantage that it is easier to continue roller running.

Figure 19 shows the harvester without a tree 22 and with the gripping claws 31.1, 31.2 ready to receive a tree. In normal,

30 problem-free delimbing, when the movement of the tree 22 through the harvester's delimbing-blade arrangement 13 takes place using the feed device 25, the grab claws 31.1, 31.2 adjust to the surface of the trunk of the tree 22. When a problem situation is detected in the delimbing, the claws 31.1,

35 31.2 press against the tree 22, thus adhering more strongly to the tree 22. It can be seen from Figure 21, that the claws 31.1, 31.2 are on different planes, so that they can overlap each other. The claws 31.1, 31.2 are arranged in such a way that the can gain a firm grip on the tree, irrespective of its diameter . 5

In Figure 22, a pulse has been made using the cylinder 30, when the rotating frame 33 of the claws 31.1, 31.2 has been rotated around the pivot point 37, relative to the harvester's frame 10. According to one embodiment, the rotation of the frame 33

10 can be in the order of magnitude of 5 - 20 degrees, for example, 10 degrees. In the vertical direction, the length of the pulse can be 100 - 250 mm, more particularly 100 - 150 mm, for example 120 mm. The delimbing blades 13.1, 13.2 grip the trunk of the tree 22 in the line of the frame of the harvester during

15 the pulse, and thus the tree 22 cannot substantially rotate from the normal direction of travel.

It can be seen from Figure 23, that there can be patterning 40, for example toothing, in the claws 31.1, 31.2 to improve adhe-

20 sion. It bites firmly into the surface of the tree 22 and ensures a pulse in the tree 22, which corresponds to the curved movement created in the gripping frame 33 by the cylinder 30. However, the tree 22 is allowed to rotate slightly in the toothing, so that it will remain close to the vertical line

25 defined by the frame 10 of the harvester. As well as, or instead of the gripping claws 31.1, 31.2, a blade 12, in which there can be cutting toothing, can also be applied to adhesion. As the gripping claws 31.1, 31.2 and/or the blade 12 are in continuous contact with the trunk of the tree 22 when the tree

30 22 is moved through the harvester by the feed device 25, the toothing 40 or similar in them also breaks the bark of the tree 22 by peeling it, which beneficially affects the drying of the timber, particularly when collecting energy timber.

35 According to one embodiment, the gripping surface 40 of the claws 31.1, 31.2 can be arranged to react to the direction of movement, i.e. to activate in the direction of the work pulse. The grip on the tree 22 will then tighten, when the pulse is activated and the claws 31.1, 31.2 move with the rotation frame 33, delimbing the tree 22 in the blade arrangement 33. Corre- spondingly, when the pulse is returned, i.e. the rotation frame 33 together with the claws 31.1, 31.2 is moved back into contact with the main frame 10 of the harvester, the grip on the tree 22 of the gripping surface 40 of the claws 31.1, 31.2 slackens and the tree 22 remains stationary in the axial direc- tion during the transfer. In other words, in the grips 40, an adhesion known from, for example, the analogy of a fishing hook can be implemented. The direction-of-travel-activated grip 40 achieves the advantage that during the activation of the pulse it is not essential to particularly increase the compressive force directed to the tree 22 by the claws 31.1, 31.2, but instead the surprisingly operating principle of the grips ensures that the grip on the trunk of the tree is sufficient to move the tree 22. The elimination of the compression stage accelerates operation, thus saving time.

Still more different possible exemplary ways to implement a corresponding pulse property transporting the tree through the delimbing-blade arrangement 13 are to move the feed means 14 linearly in the axial direction, or in a corresponding manner in a rotary manner, as is done in the embodiment according to Figures 19 - 23, with the rotation-frame package 33 formed by the gripping claws 31.1, 31.2 and the cutting blade 12.

Besides the harvester described by way of example above, the invention also relates to a method in timber harvesting using a harvester. In it the tree 22 is cut and run axially through the harvester using a feed device 25 while simultaneously delimbing the branches from it using a delimbing-blade. arrangement 13. In the method, the operation of the feed device 25 is also monitored while the tree 22 is being run through the harvester. When a set criterion concerning the operation of the feed device 25 is met, the delimbing is performed momentarily as pulsed delimbing. In it, the delimbing-blade arrangement 13 and the tree 22 being delimbed are brought into a motion relative to each other in order to create at least one impact on at least one branch that is at the location of the delimbing-blade arrangement 13. Thus the delimbing-blade arrangement 13 can be used to give at least one branch at the location corresponding to it at least one impact and/or the tree 22 can be moved by an axial pulse, relative to the delimbing-blade arrangement 13. If the feed device 25 is based on rotating members, the set criterion can be, for example, that the feed device 25 ceases to rotate and/or slips, relative to the tree 22. According to one embodiment, the impacts can be given as a series, by repeating them, for example, until the set criterion concerning ^■ the feed device 25 is met.

When performing bundle processing of trees using a harvester, according to the embodiment, without additional claws, at least one tree 22 is picked into the delimbing circle formed by the delimbing arrangement 13 formed by the delimbing blades 13.1 - 13.3, 36 by approaching the tree 22 with the delimbing blades 13.1, 13.3, equipped with pivots 35, closed. The pivoting 35 of the blades 13.1, 13.3 then permits the delimbing blades 13.1, 13.3 to move out of the way of the tree 22 being picked up. When the tree 22 is pressed against the delimbing blades 13.1, 13.3, and when the delimbing blades 13.1, 13.3 are opened slightly by rotating the arms 16, the delimbing blades 13.1, 13.3 turn inwards out of the way of the tree 22 and allow the tree 22 to enter the delimbing circle and return, for example spontaneously, to the delimbing position, in which they define the delimbing circle. After this, the delimbing circle can be closed around the trees by the arms 16 and the tree 22 can be cut. This is repeated, until the desired number of trees are in the delimbing circle. After this, delimbing is performed using the delimbing-blade arrangement 13. The harvester's power requirement is surprisingly small relative to harvesters according to the prior art. For example, in pilot-stage tests delimbing could be performed on 200-mm tree trunks using a power of as little as only 15 kW, whereas in device according to the prior art the power requirement could be as much as 150 kW.

It must be understood that the above description and the related figures are only intended to illustrate the present invention. The invention is thus in no way restricted to only the embodiments disclosed or stated in the Claims, but many different variations and adaptations of the invention, which are possible within the scope on the inventive idea defined in the accompanying Claims, will be obvious to one versed in the art.