Reaction bar for tree treatment tool, tool and forestry machine

Abstract

The invention relates to a reaction rod (26) for a tool (10) for treating trees (11), arranged to connect a support element (18) of the tool (10) for synchronizing the movement of the support element (18), the reaction rod (26) comprising a first end (28) and a second end (30) for hinging the reaction rod (26) to the tool (10), wherein the first end (28) comprises a pivot bushing (38) for hinging the reaction rod (26) to the support element (18), and the reaction rod (26) further comprises a rotary eccentric element (35) arranged at the first end (28), the pivot bushing (38) being eccentrically formed at the first end. The invention also relates to a tree treatment tool and a forestry machine.

Description

Technical Field

[0001] The invention relates to a reaction bar for a tree handling tool, the reaction bar being arranged to be connected to a support element of the tool for synchronous movement, the reaction bar comprising a first end and a second end for articulating the reaction bar to the tool, wherein the first end comprises a pivot bushing for articulating the reaction bar to the support element.

[0002] The invention also relates to a tree handling tool and a forestry machine. Background Art

[0003] Tools for handling trees, such as feller heads or grapples, use support elements to grab trees for handling. Figure 1 In the harvester head 52 shown, these support elements 18 may comprise feed rollers 48 according to the figure, or feed reels or delimbing knives, while in a grapple they comprise grapple hooks. The different sizes of trees can create problems when handling trees of different sizes in a multi-trunk process, i.e. when handling several trees at once. Figure 2a Attempts have been made to use reaction rods 26 to synchronize the movement of the support elements 18 against the trees 11 so that the support elements 18 support trees 11 of uniform size evenly. However, in the case of trees 11 of different sizes, this is disadvantageous because the movement of the support elements 18 is stopped according to the largest tree 11, e.g. Figure 2b In this case, the pressure applied to the smaller tree can be kept low or completely absent, making it more difficult or impossible to treat the tree. Summary of the invention

[0004] The object of the invention is to provide a reaction rod with which a more effective support of a synchronizable support element against trees of different sizes can be achieved compared to reaction rods of the prior art. The characteristics of the reaction rod according to the invention are set forth in the attached claim 1. Another object of the invention is to provide a tool and a forestry machine with which a more effective support of a synchronizable support element against trees of different sizes can be achieved compared to the prior art. The characteristics of the tool according to the invention are set forth in the attached claim 8 and the characteristics of the forestry machine are set forth in the attached claim 15.

[0005] The object of the reaction lever according to the invention can be achieved by a reaction lever for a tree handling tool, the reaction lever being arranged to be connected to a support element of the tool for synchronous movement, the reaction lever comprising a first end and a second end for articulating the reaction lever to the tool, wherein the first end comprises a pivot bushing for articulating the reaction lever to the support element. Furthermore, the reaction lever comprises a rotating eccentric element arranged at the first end, the pivot bushing being eccentrically formed at the eccentric element.

[0006] When using a tool comprising a reaction bar according to the invention to treat trees of different sizes, trees of different sizes all receive sufficient support from the support element, since the support element located at smaller trees can also be moved into good contact with said trees, since the pivot point of the first end of the reaction bar is allowed to move further away from the second end of the reaction bar thanks to the eccentric element. In other words, the articulated structure enables the movement of the support element to be deviated synchronously when the support element moves against trees of different sizes. As a result, the support element can be rotated more and good contact with said trees is achieved for all trees supported by the support element of the tool. When using an eccentric element, the necessary displacement of the pivot point for increasing the trajectory of the support element occurs smoothly and there are no collisions that wear out the pivot point when it moves along a circular track together with the eccentric element.

[0007] Advantageously, the eccentric element is a sleeve.

[0008] In the present context, a "reaction rod" is understood to mean a rod which connects support elements together and which transmits forces between two support elements in order to at least partially synchronize the movements of the two support elements.

[0009] In other words, the rotating eccentric element and the pivot bushing form an articulated structure, which enables the pivot point to be displaced if necessary.

[0010] The sleeve may also be referred to as a disc or a circular support element.

[0011] Advantageously, the pivot bushing of the eccentric element is adapted to a pivot pin which, via the pivot bushing, is used to connect the reaction rod to the tool at a first end of the reaction rod.

[0012] According to an embodiment, there is a stop connected to the eccentric element for limiting the rotation of the eccentric element to less than 180° in order to prevent the eccentric element from blocking. Thanks to the stop, it is avoided that the pivot opening and the forces acting on it on the opposite side of the axis of rotation of the eccentric element end up in a straight line, that is, at the so-called dead point, at which the forces cannot provide a rotational movement of the eccentric element.

[0013] The limiter may include a recess formed on an outer edge included in the eccentric element, the recess extending on the outer edge over only a portion of the length of the outer edge, and the limiter includes a limiting protrusion formed near the opening at the first end of the reaction rod, the limiting protrusion extending from the inner edge of the opening toward the center point of the opening, for limiting the rotation of the eccentric element against the edge included in the recess.

[0014] Advantageously, the limiting projection is formed in a flange which is fastened to a surface of the reaction rod in the planar direction of the opening.

[0015] The eccentricity, i.e. the offset of the pivot bushing from the center of the eccentric element, can be dimensioned so that a deviation between 50 mm and 200 mm, preferably between 80 mm and 150 mm, is achieved for the support element for synchronization. In addition to the eccentricity of the pivot bushing, the achieved deviation also depends on the geometry of the support arm used, which is a tool-specific variable.

[0016] According to an embodiment, the reaction lever comprises a locking device for locking the eccentric element against rotation. In this way, when treating trees of substantially uniform size, the movement of the support elements can be perfectly synchronized. This reduces wear on the articulated structure of the reaction lever.

[0017] For example, the locking device may include a bolt arranged to move in a radial direction relative to the eccentric element and to move in a radial direction into a locking hole formed in the eccentric element. For example, the bolt may be a manually operated bolt or a bolt driven by a hydraulic or electric actuator.

[0018] Advantageously, the reaction rod comprises at least one flange, which is arranged to be locked to the first end of the reaction rod for locking the eccentric element in the direction of the rotation axis of the eccentric element. With the flange, the eccentric element can be prevented from falling out of the opening in a simple manner.

[0019] Advantageously, there are two flanges, each arranged on one side of the reaction rod, for locking the eccentric element in the opening between the flanges. In this case, the structure of the eccentric element can be quite simple, because the support of the eccentric element in the direction of the rotation axis is achieved by using flanges.

[0020] At least one of the flanges preferably comprises a pin hole for a pivot pin.

[0021] Advantageously, the pivot pin of the hinge structure can be a bolt which has a smooth, non-threaded section between its ends in the region of the eccentric element.

[0022] The reaction rod is preferably curved. Thus, the curved reaction rod leaves space in the tool jaws for trees in, for example, a felling machine head.

[0023] However, the eccentricity of the eccentric element may be between 5% and 45% of the eccentric element diameter, so that the wall thickness between the outer edge included in the sleeve and the pivot bushing is at least 4 mm. In this way, sufficient additional play is achieved to enable the support element to move against the tree.

[0024] A grease nipple is advantageously arranged at the first end of the reaction rod for supplying lubricant between the eccentric element and the opening. This helps to improve the resistance of the articulation by reducing the friction between the components.

[0025] The purpose of the tool according to the invention can be achieved by a tool for handling trees arranged to be suspended on a crane, wherein the tool comprises: a frame; two opposing support elements for handling trees, each support element comprising a support arm; at least one actuator for rotating the support elements around the tree relative to the frame; and a reaction rod arranged to connect the support arms to synchronize the movement of the support elements, the reaction rod comprising a first end and a second end. In addition, the tool comprises an articulation formed between the first end of the reaction rod and one of the support arms, and an articulation formed between the second end and the other support arm, wherein each articulation comprises a pivot pin and a pivot bushing. One of the articulations comprises an eccentric element, the pivot bushing is eccentrically formed in the eccentric element, and the pivot pin is connected to the eccentric element for enabling asynchronous movement of the support element by rotation of the eccentric element.

[0026] Advantageously, the tool comprises at least one actuator for rotating the support element relative to the frame around the tree.By using an actuator in this way, it is also possible to take advantage of the increased travel length of the support element achieved by the eccentric element.

[0027] According to an embodiment, the eccentric element is arranged in the reaction rod, the support arm comprises a pivot bushing, and the hinge further comprises a pivot pin arranged between the pivot bushing of the eccentric element and the pivot bushing of the support arm.

[0028] According to another embodiment, an eccentric element is arranged in the support arm, the reaction lever comprises a pivot bushing, and the hinge further comprises a pivot pin arranged between a pivot bushing of such eccentric element and a pivot bushing of the support arm.

[0029] According to a third embodiment, the pivot pin can be formed integrally in the eccentric element or as a corresponding part of the hinge without the eccentric element.

[0030] According to an embodiment, the tool is a harvester head, which also comprises a cutting device, and the support element comprises feed rollers for feeding the trees to the cutting device and at least one support arm for each feed roller, which support arm is used to articulate each feed roller to the frame. With regard to the feed rollers, it is particularly important that a close contact is achieved also when processing trees of different sizes, so that the trees can be fed effectively to the cutting device and the feed rollers cannot slide against the trees, as this would damage the trees.

[0031] The reaction rod is preferably arranged between the support arms.

[0032] Advantageously, the tool comprises a pivot arm formed in one of the support arms and a reaction rod arranged to connect the support arms using the pivot arm. With the pivot arm, the synchronization of the support arms can be achieved using a simple fixed reaction rod, since the force transmitted by the reaction rod is transmitted from one support arm to the other support arm on the opposite side relative to the pivot point, with the pivot arm acting as an extension of the support arm. Correspondingly, the force on the reaction arm comes from the actuator, which moves the support arm and thus the reaction rod fixed to the support arm.

[0033] According to an embodiment, the reaction rod is connected to the support arm by its first end through a pivot arm.Alternatively, the first end may be directly connected to the support arm, in which case the other end of the reaction rod is connected to the support arm through a pivot arm.

[0034] In other words, when the implement is a felling head, the first end of the reaction bar connected to the support arm directly or via a pivot arm forms a pivot point having a variable distance from the second end of the reaction bar depending on the required travel length of the support element in order to handle trees.

[0035] According to another embodiment, the tool is a felling machine head, wherein the support element comprises a delimbing knife for removing branches from trees. With regard to the operation of the delimbing knife, it is also necessary that the delimbing knife needs to be in contact with all trees processed simultaneously so that the delimbing knife removes branches from the tree trunk as close as possible to the tree trunk. In the case of a delimbing knife, a reaction rod is correspondingly used to synchronize the movement of the delimbing knife.

[0036] For the delimbing knives, the reaction lever may be fastened to a pivot arm which may be formed in each delimbing knife being an extension of the delimbing knife.

[0037] According to a third embodiment, the tool is a felling machine head comprising a cutting device and two pairs of supporting elements formed by two opposing supporting elements, one pair of supporting elements comprising feed rollers for feeding the tree to the cutting device and at least one supporting arm for each feed roller, the supporting arm being used to articulate each feed roller to the frame, and the other pair of supporting elements comprising delimbing knives for delimbing the tree while feeding the tree to the cutting device via the feed rollers. In this way, both the delimbing knives and the feed rollers achieve good contact with the tree.

[0038] According to a fourth embodiment, the tool is a grapple and the support element is a grapple. When loading trees, sufficient contact between the grapple and the tree is also important to avoid that the tree falls between the grapple, for example, when the grapple is tilted.

[0039] For a grapple, the reaction bar may be fastened to a pivot arm which may be formed in each grapple as an extension of the grapple.

[0040] The object of a forestry machine according to the invention can be achieved by a forestry machine comprising any of the aforementioned embodiments of the tool according to the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] The present invention is not limited to the embodiments given below, but will be described in more detail with reference to the accompanying drawings, in which:

[0042] Figure 1 is a side isometric view of a prior art harvester head in a vertical position with feed rollers open;

[0043] Figure 2a is a partial cross-sectional view of a prior art tool along the tree direction with a tree of uniform size supported by feed rollers;

[0044] Figure 2b Shown are trees of different sizes supported by feed rollers Figure 2a Existing technical tools;

[0045] Figure 3 is a side axonometric view of the harvester head in a horizontal position with the feed rollers open;

[0046] Figure 4 Shows the feller head in the direction of the tree with the feed rollers open;

[0047] Figure 5a is a partial cross-sectional view of the tool according to the invention with trees of different sizes supported by the feed rollers and with the articulated member in one end position;

[0048] Figure 5bis a partial cross-sectional view of the tool according to the invention with trees of different sizes supported by the feed rollers and with the articulated member in the other end position;

[0049] Figure 6a is an axonometric view of the separated reaction bar;

[0050] Figure 6b is an exploded axonometric view of the separated reaction bar;

[0051] Figure 7 is a side view of the reaction bar;

[0052] Figure 8 is an exploded isometric view of a separated reaction rod according to another embodiment;

[0053] Fig. 9 It is an axonometric view of a detached delimbing knife;

[0054] Fig.10 It is an axonometric view of the grab as a tool;

[0055] Fig.11 A forestry machine according to the invention is shown;

[0056] Fig.12 is a side view of the tool according to the invention also showing the fastening of the reaction rod and the actuator to the frame of the support element.

[0057] In the drawings, the following reference numerals are used to indicate the different components of the present invention:

[0058] 10 Tools 52 Harvester Head

[0059] 11 Trees 54 Delimbing Knife

[0060] 12 Hanger 56 Support arm pivot point

[0061] 16 Frame 58 Jaw

[0062] 18 Support element 60 Flange

[0063] 20 Actuator 62 Pin hole

[0064] 22 Support arm 64 Grease nipple

[0065] 24 pivot arm 65 second opening

[0066] 26 Reaction rod 66 Pivot bushing

[0067] 27 Reaction rod lug 68 Grease nipple

[0068] 28 First end 70 bolt

[0069] 30 Second end 72 Locking bolt

[0070] 32 hinge 74 locking hole

[0071] 34 opening 76 convex part

[0072] 35 Eccentric element 78 Recess

[0073] 36 Socket 80 Forestry Machines

[0074] 38 Pivot Bushing 82 Crane

[0075] 40 Pivot pin 84 Grab bucket

[0076] 40a Alternative end positions for pivot pin 86 Grab hook

[0077] 42 Pivot Point 90 Recess

[0078] 44 limiter 92 limit convex part

[0079] 46 The outer edge of the cutting device 94 eccentric element.

[0080] 48 Feed Roller

[0081] 50 Locking device DETAILED DESCRIPTION

[0082] Figures 3 to 5b An advantageous embodiment of a tool according to the invention is shown, wherein the tool is a felling head 52 for felling preferably by Figures 3 to 5b The hanger 12 is suspended on Fig.11 Although the working principle of the present invention is described with reference to a harvester head and feed rollers used as supporting elements and their supporting arms, those skilled in the art will recognize that the present invention can also be used in Fig. 9 The delimbing knife 54 and Fig.10 The grapple 84 is shown to synchronize the grapple 86 through the use of the reaction bar 26 .

[0083] Although embodiments are always described with reference to the drawings in which the articulation between the reaction rod and the support arm of the support element is realized in such a way that the eccentric element is arranged as part of the reaction rod, a pivot bushing is included in the support arm of the support element and a pivot pin is provided between them, a person skilled in the art will recognize that the invention can also be realized in another way. In an alternative embodiment, the eccentric element can be arranged in the support arm. Furthermore, the pivot pin can be a separate component arranged between the pivot bushings of the articulation, or it can be an integral part of the reaction rod and that part of the support arm without the eccentric element, or it can be an integral part of the eccentric element.

[0084] according to Figure 3 and Figure 4 The harvester head 52 used as the tool 10 comprises a frame 16 and a support element 18 hinged to the frame 16, the support element 18 comprising Figure 3 and Figure 4 The harvester head 52 includes a feed roller 48 and a support arm 22. In addition, the harvester head 52 includes a reaction bar 26 according to the present invention, such as Figure 5a and Figure 5b As best shown, the reaction rod 26 is preferably connected to the support element 18 via the support arm 22. In addition, the harvester head 52 includes an actuator 20 articulated between the frame 16 and the support arm 22 for rotating the support arm 22 around its pivot point 56, as shown in FIG. Figure 5a and Figure 5b One or two actuators may be provided. Figure 4 The use of two actuators 20 is shown, where if the actuators are cylinders, each actuator is Figures 5a to 5b When only one actuator is used, it is articulated directly between the two support arms 22. In addition, the harvester head 52 typically also comprises a cutting device 46 and a delimbing knife 54, the synchronization of which can also be performed with the reaction bar according to the invention.

[0085] Figure 5a and Figure 5bA situation in which the advantages of the tool 10 according to the invention are realized is shown in a partial cross-sectional view. In this case, two trees 11 of different sizes are located in the jaws 58 formed in the feller head 52 between the frame 16 and the feed rollers 48. Both feed rollers 48 are in close contact with the trees 11, regardless of whether the trees have different diameters. This is achieved by means of a reaction rod 26 according to the invention, which is articulated to the support arm 22 of the feed rollers 48 via an articulation 32. The articulation 32 comprises pivot bushings 38, 66 in the support arm 22 and the reaction rod 26, a pivot pin 40 and an eccentric element 35, enabling the pivot point 42 formed between the first end 28 of the reaction rod 26 and the support arm 22 to move. The eccentric element is hereinafter referred to as a sleeve. Alternatively, in Figure 5a and Figure 5b In this case, the pivot point 42 may be formed in the support arm 22 between the pivot arm 24 on the other side of the pivot point 56 fastened to the support arm 22 and the first end 28 of the reaction rod 26 . Figure 5a and Figure 5b The additional movement of the support element between the two end positions of the sleeve of the hinge which can be achieved by the hinge is shown. More specifically, the force provided by the actuator causes the support arm 22 to rotate about the pivot point 56.

[0086] according to Figure 6b The reaction rod 26 includes a first end 28 and a second end 30, between which the reaction rod 26 is preferably curved to prevent the reaction rod 26 from restricting the space in the jaws of the harvester head. In different applications, the shape of the reaction rod may also be different, for example, Fig.10 Arranged at the first end 28 of the reaction rod 26 is an opening 34, to which a sleeve 36 serving as an eccentric element is mounted. In turn, a pivot bushing 38 is eccentrically formed in the sleeve 36, enabling a pivot pin 40 arranged through the pivot bushing to be moved by rotating the sleeve 36 to different distances from the second end 30 of the reaction rod 26, which is fixedly hinged to the opposite support arm. Figure 7 The pivot pin 40 and its alternative end positions are depicted in phantom using reference numeral 40a. The second end 30 of the reaction bar 26 preferably includes a second opening 65 that is substantially parallel to the opening at the first end 28.

[0087] Advantageously, the sleeve 36 is locked to the opening 34 by means of two flanges 60 having pin holes 62, also as Figure 6b As shown, the pin hole corresponds to the trajectory of the pivot pin machined in at least one of the flanges. Advantageously, according to Figure 7, the pin hole 62 includes a straight surface 41 and a curved surface 43, wherein the straight surface 41 is preferably oriented in the same direction as the movement of the pivot pin 40 in the trajectory of the support element toward the smaller tree. The flange 60 can be fastened to one side of the reaction rod 26, for example using bolts 70. According to Figure 6b , the flanges 60 may include a protrusion 76 extending from their main shape, for which a correspondingly shaped recess 78 is also formed in the reaction rod 26. This prevents rotation of the flanges.

[0088] For a sleeve with a diameter of 80 mm, the eccentricity or offset of the pivot bushing in the sleeve can be, for example, 10 mm from the centre point of the sleeve, in which case the displacement of the pivot point achieved during the rotation of the sleeve is 20 mm. More generally, however, the eccentricity of the sleeve can be between 5% and 45% of the sleeve diameter, so that the wall thickness between the outer edge of the sleeve and the pivot bushing is at least 4 mm but does not exceed 30% of the sleeve diameter. For example, the sleeve diameter can be between 40 mm and 160 mm. The eccentricity is determined by the necessary synchronous deviation of the feed roller so that the feed roller also contacts smaller trees in the jaws. In addition, the eccentricity is influenced by the dimensioning of the support arm, the reaction rod and the pivot point of the support arm. The aim is to enable close contact for trees that are up to 40% smaller than larger trees.

[0089] The sleeve can be mounted to the opening of the reaction rod using a bearing. Alternatively, the sleeve and the opening can also be made of hardened steel, in which case the only Figure 6b The grease nipple 64 shown is sufficient for lubrication. In this case, the reaction rod and flange are made of wear-resistant steel. In this application, a certain degree of play will not cause problems.

[0090] according to Figure 6b , the reaction bar 26 may include a locking device 50 for locking the sleeve 36 against rotation so that when dealing with trees of substantially uniform size, the sleeve remains in place and the movement of the support elements can be fully synchronized. Figure 6b In the embodiment of FIG. 5 , the locking device 50 is constituted by a locking bolt 72 which is arranged to move along the radial direction of the sleeve 36 and enter into a locking hole 74 formed in the sleeve 36 along the radial direction.

[0091] Fig.12 2 is a side view showing the support arm 22 articulating the reaction rod 26 and the actuator 20 to the support element 18. Fig.12The reaction rod 26 is fastened to a surface of the support arm 22 by means of a lug 27 of the reaction rod 26, which is in a substantially different plane from the pivot arm 24 for fastening the actuator. In this way, the actuator 20 and the reaction rod 26 do not collide with each other under any circumstances, and the sleeve 36 of the reaction rod 26 enables the first end 28 of the reaction rod 26 to move in a curved trajectory.

[0092] according to Figure 8 The hinge 32 may further include a stopper 44 for limiting the degree of rotation of the sleeve 36. Figure 8 In the advantageous embodiment shown, the stop 44 comprises a recess 90 formed in the sleeve, along the outer edge of the sleeve and having an edge length of less than 180°. By adopting such a dimensioning, the recess 90 limits the rotation of the sleeve 36 and prevents the sleeve from rotating to a position in which its pivot pin is located in a so-called dead point relative to the forces acting on it, in which case the forces cannot provide a rotation of the sleeve when necessary. The stop 44 also includes a limiting protrusion 92, which is formed in the flange at the first end of the reaction rod or in the opening 34, extends towards the central part of the sleeve and is arranged to pass through a groove formed in the sleeve. When the sleeve rotates, the limiting protrusion collides with the end of the sleeve recess and in this way prevents further rotation of the sleeve.

[0093] In the embodiment where the tool is a felling head, the diameter of the feed roller of the felling head may be between 300 mm and 600 mm, the diameter of the tree being processed may be between 200 mm and 1200 mm, and the size of the reaction bar may be between 1000 mm and 1500 mm. In this case, the sleeve diameter may be between 40 mm and 160 mm.

Claims

1. A reaction rod (26) of a tool (10) for handling trees (11), the reaction rod being arranged in connection with a support element (18) of the tool (10) in order to synchronize the movement of the support element (18), the reaction rod (26) comprising a first end (28) and a second end (30) for articulating the reaction rod (26) to the tool (10), wherein the first end (28) comprises a pivot bushing (38) for articulating the reaction rod (26) to the support element (18), characterized in that The reaction lever (26) further comprises a rotating eccentric element (35) arranged at the first end (28), the pivot bushing (38) being eccentrically formed at the eccentric element.

2. The reaction rod according to claim 1, characterized in that The eccentric element (35) is a sleeve (36).

3. The reaction rod according to claim 1 or 2, characterized in that The tool (10) comprises a stopper (44) for limiting the rotation of the eccentric element (35) to less than 180° to prevent the eccentric element (35) from being blocked.

4. A reaction rod according to any one of claims 1 to 3, characterized in that The reaction lever (26) comprises a locking device (50) for locking the eccentric element (35) against rotation.

5. A reaction rod according to any one of claims 1 to 4, characterized in that The reaction rod (26) comprises at least one flange (60) arranged to be locked to the first end (28) of the reaction rod (26) in order to lock the eccentric element (35) in the rotation axis of the eccentric element (35).

6. A reaction rod according to any one of claims 1 to 5, characterized in that The eccentricity of the eccentric element (35) can be between 5% and 45% of the diameter of the eccentric element (35), however, such that the wall thickness comprised between the outer edge (94) of the eccentric element (35) and the pivot bushing (38) is at least 4 mm.

7. A reaction rod according to any one of claims 1 to 6, characterized in that A grease nipple (64) is formed at the first end (28) of the reaction rod (26) for supplying lubricant between the eccentric element (35) and the opening (34).

8. A tool (10) for handling trees (11), said tool being arranged to be suspended from a crane (82), said tool (10) comprising: - frame (16), - two opposing support elements (18) for handling trees (11), each support element (18) comprising a support arm (22), - at least one actuator (20) for rotating the support element (18) relative to the frame (16) around the tree (11), a reaction rod (26) arranged to connect the support arm (22) to synchronize the movement of the support element (18), the reaction rod (26) comprising a first end (28) and a second end (30), - an articulated member (32) formed between the first end (28) of the reaction rod (26) and one of the support arms (22) and between the second end (30) and the other of the support arms (22), wherein each articulated member (32) comprises a pivot pin (40) and a pivot bushing (38, 66), characterized in that one of the articulated members (32) comprises an eccentric element (35), the pivot bushing (38) being eccentrically formed in the eccentric element and the pivot pin (40) being connected to the eccentric element (35) for enabling asynchronous movement of the support element (18) by rotation of the eccentric element (35).

9. The tool according to claim 8, characterized in that The tool (10) is a harvester head (52), which also includes a cutting device (46), and the support element (18) includes feed rollers (48) for feeding trees (11) to the cutting device (46) and at least one support arm (22) for each feed roller (48), which is used to articulate each feed roller (48) to the frame (16).

10. The tool according to claim 8, characterized in that The tool (10) is a felling head (52), wherein the support element (18) is a delimbing knife (54) for delimbing trees (11).

11. The tool according to claim 8, characterized in that The tool (10) is a felling machine head (52) comprising a cutting device (46) and two pairs of support elements (18), wherein one pair of support elements (18) comprises feed rollers (48) for feeding trees to the cutting device (46) and at least one support arm (22) for each feed roller (48), the support arm being used to articulate each feed roller (48) to the frame (16), and the other pair of support elements (18) consists of delimbing knives (54) for delimbing trees while feeding the trees to the cutting device (46) via the feed rollers (48).

12. The tool according to claim 8, characterized in that The tool (10) is a grapple (84) and the support element (18) is a grapple (86).

13. The tool according to any one of claims 8 to 12, characterized in that The actuator (20) and the reaction rod (26) are both hinged to the support element (18) at different heights relative to each other.

14. The tool according to any one of claims 8 to 13, characterized in that The eccentricity of the pivot bushing (38) relative to the center point of the eccentric element (35) is designed so that the support elements (18) achieve a deviation of 50 mm to 200 mm, preferably 80 mm to 150 mm, so that the support elements (18) are synchronized.

15. Forestry machine comprising a crane and a tool (10) suspended from the crane for handling a tree (11), wherein the tool (10) comprises a support element (18) for handling the tree (11), characterized in that The tool (10) is a tool (10) according to any one of claims 8 to 14.

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