The invention is related to a reaction bar for a tree processing tool arranged to connect the support elements of the tool for synchronising movements, the reaction bar comprising a first end and a second end for articulating the reaction bar to the tool, wherein the first end includes a pivot bushing for articulating the reaction bar to the support element.

The invention is also related to a tree processing tool and a forest machine.

Tools for processing trees, such as harvester heads or grabs grab trees using support elements for processing trees. In the harvester head 52 shown in Figure 1, such support elements 18 can consist of feeding rollers 48 according to the figure or feeding rolls or delimbing knives, whereas in grabs, they are composed of grapples. When processing trees of different sizes in multi-stem processing, that is, several trees at a time, trees of different sizes can cause problems. According to Figure 2a, it has been strived to synchronise the movement of support elements 18 against trees 11 using a reaction bar 26 so that the support elements 18 are evenly supported to trees of a uniform size 11. However, in the case of trees 11 of different sizes, this is harmful as the movements of the support elements 18 stop according to the biggest tree 11 as shown in Figure 2b. In this case, pressure applied to the smaller tree may remain low or be completely absent, which makes it more difficult to process this tree or completely prevents it .

The object of this invention is to provide a reaction bar with which it is possible to achieve more efficient supporting of synchronisable support elements against trees of different sizes than with prior art reaction bars. The characteristic features of the reaction bar according to the invention are set forth in the appended Claim 1. Another object of the invention is to provide a tool and a forest machine wherein more efficient supporting of synchronisable support elements against trees of different sizes is achieved compared to prior art. The characteristic features of the tool according to the invention are set forth in the appended Claim 8 and the characteristic features of the forest machine in the appended Claim 15.

The object of the reaction bar according to the invention can be achieved with a reaction bar for a tree processing tool, which is arranged to connect the support elements of the tool for synchronising movements, the reaction bar comprising a first end and a second end for articulating the reaction bar to the tool, wherein the first end includes a pivot bushing for articulating the reaction bar to the support element. In addition, the reaction bar includes a rotating eccentric element arranged at the first end, at which said pivot bushing is formed eccentrically.

When processing trees of different sizes with a tool that comprises a reaction bar according to the invention, both trees receive sufficient support from the support elements, since the support element located at the smaller tree can also move to a good contact with the tree as 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, an articulated structure enables a synchronisation deviation for the movement of the support elements when moving the support elements against trees of different sizes. Thus, the support element can rotate more, and a good contact with the tree is achieved for all trees supported by the support elements of the tool. When using an eccentric element, the necessary displacement of the pivot point for increasing the trajectory of the support elements takes place smoothly and without collisions that wear the pivot point as the pivot point moves with the eccentric element along the circular track.

Advantageously, the eccentric element is a sleeve.

In this context, 'reaction bar' means a bar that connects together support elements and transmits force between two support elements for synchronising their movements at least partly .

In other words, a rotating eccentric element and a pivot bushing form an articulated structure, which enables a displacement of the pivot point when necessary.

The sleeve can also be called a disc or a round support element.

Advantageously, the pivot bushing of the eccentric element is adapted for a pivot pin, which goes through the pivot bushing for connecting the reaction bar to the tool at its first end.

According to an embodiment, there is a limiter in connection with the eccentric element for limiting the rotation of the eccentric element below 180° for preventing blocking of the eccentric element. Thanks to the limiter, it can be avoided that the pivot opening ends up in the same line with the force acting on it on the opposite side of the axis of rotation of the eccentric element, that is, at the so-called dead centre, where force cannot provide a rotational motion of the eccentric element . The limiter may include a recess formed on the outer rim included in the eccentric element, extending on the outer rim only over a part of the length of the outer rim, and a limiting projection formed near the opening at the first end of the reaction bar, extending from the inner rim of the opening towards the centre point of the opening, for limiting the rotation of the eccentric element against the edges included in the recess .

Advantageously, the limiting projection is formed in a flange, which is fastened to the surface of the reaction bar in the plane direction of the opening.

The eccentricity, i.e. , offset of the pivot bushing from the centre of the eccentric element can be dimensioned in such a way that a deviation between 50 mm and 200 mm, preferably a deviation between 80 mm and 150 mm, is achieved for the support element for synchronisation. In addition to the eccentricity of the pivot bushing, the deviation achieved depends on the geometry of the support arms used, which is a tool-specific variable .

According to an embodiment, the reaction bar includes locking devices for locking the eccentric element non-rotating. In this way, the movements of the support elements can be completely synchronised when processing trees of essentially a uniform size. This reduces wearing of the articulated structure of the reaction bar.

For example, locking devices may consist of a bolt, which is arranged to move in the radial direction relative to the eccentric element and into a locking hole formed in the eccentric element in the radial direction. The bolt may be a manually operated bolt or a bolt driven with a hydraulic or electric actuator, for example.

Advantageously, the reaction bar includes at least one flange arranged to lock to the first end of the reaction bar for locking the eccentric element in the direction of the axis of rotation of the eccentric element. With the flange, it is possible to prevent in a simple way that the eccentric element falls out from the opening.

Advantageously, there are two flanges, each arranged on one side of the reaction bar for locking the eccentric element in the opening between the flanges. In this case, the structure of the eccentric element can be rather simple, as its supporting in the direction of the axis of rotation is implemented with flanges.

At least one of the flanges preferably includes a pin hole for a pivot pin.

Advantageously, the pivot pin of the articulated structure can be a bolt having a smooth unthreaded part between the ends in the area of the eccentric element.

The reaction bar is preferably curved. Thus, a curved reaction bar leaves space in the tool jaw for trees in harvester heads, for example.

The eccentricity of the eccentric element can be between 5% and 45% of the diameter of the eccentric element, however, 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, a sufficient additional play is achieved enabling the movement of support elements against a tree. A grease nipple is advantageously arranged at the first end of the reaction bar for supplying lubricant between the eccentric element and the opening. This helps improve the resistance of the articulation by reducing the friction between the components .

The object of the tool according to the invention can be achieved with a tool for processing trees arranged to be suspended on a crane, wherein the tool includes a frame, two opposite support elements for processing trees, each support element comprising a support arm, at least one actuator for rotating the support elements relative to the frame around the trees, and a reaction bar arranged to connect the support arms for synchronising movements of the support elements, the reaction bar comprising a first end and a second end. In addition, the tool includes articulations formed between the first end of the reaction bar and one support arm and between the second end and the other support arm, wherein each articulation includes a pivot pin and a pivot bushing. One of the articulations includes an eccentric element in which the pivot bushing is formed eccentrically, and the pivot pin is connected to the eccentric element for enabling an out of synch movement of the support elements by means of a rotation of the eccentric element.

Advantageously, the tool includes at least one actuator for rotating the support elements relative to the frame around trees. With such a use of the actuator, it is also possible to utilise an increased travel length of the support element achieved with the eccentric element.

According to an embodiment, the eccentric element is arranged in the reaction bar and the support arm includes a pivot bushing and the articulation further includes a pivot pin arranged between the pivot bushings of such eccentric element and support arm.

According to another embodiment, the eccentric element is arranged in the support arm and the reaction bar includes a pivot bushing and the articulation further includes a pivot pin arranged between the pivot bushings of such eccentric element and support arm.

According to a third embodiment, the pivot pin can be either integrated in the eccentric element or a part of a component of the articulation corresponding to it, which is without an eccentric element.

According to an embodiment, the tool is a harvester head, which additionally includes a cutting device, and the support elements include feeding rollers for feeding trees to the cutting device and at least one support arm for each feeding roller for articulating each feeding roller to the frame. Regarding feeding rollers, it is particularly important that a firm contact is also achieved when processing trees of different sizes in order that trees can be efficiently fed to the cutting device and the feeding roller cannot slide against a tree, which damages trees.

The reaction bar is preferably arranged between the support arms .

Advantageously, the tool includes a pivot arm formed in one of the support arms and a reaction bar arranged to connect the support arms using said pivot arm. With the pivot arm, synchronisation of the support arms can be implemented using a simple fixed reaction bar, as the force delivered by the reaction bar is transmitted from one support arm to the other support arm to the opposite side relative to the pivot point, with the pivot arm functioning as an extension to the support arm. In turn, force to the reaction arm comes from the actuator, which moves the support arms and thereby the reaction bar fastened to these.

According to an embodiment, the reaction bar is connected to the support arm by its first end by means of a pivot arm. Alternatively, the first end may be connected directly to the support arm, in which case the other end of the reaction bar is connected to the support arm by means of the pivot arm.

In other words, when the tool is a harvester head, the first end of the reaction bar that is connected to the support arm directly or by means of a pivot arm forms a pivot point having a variable distance from the second end of the reaction bar according to the necessary travel length of the support elements, for processing trees.

According to another embodiment, the tool is a harvester head in which the support elements consist of delimbing knives for delimbing trees. Regarding the operation of delimbing knives, it is also essential that delimbing knives are essentially in contact with all of the trees that are processed simultaneously in order that the delimbing knives remove branches from the tree stem as close as possible to the stem. In the context of delimbing knives, a reaction bar is correspondingly used for synchronising the movements of the delimbing knives.

For delimbing knives, the reaction bar can be fastened to a pivot arm, which can be an extension to the delimbing knife, formed in each delimbing knife. According to a third embodiment, the tool is a harvester head, which includes a cutting device and two pairs formed of two opposite support elements, wherein the support elements of one pair include feeding rollers for feeding trees to the cutting device and at least one support arm for each feeding roller for articulating each feeding roller to the frame, and the support elements of the other pair consist of delimbing knives for delimbing trees while feeding them to the cutting device by means of the feeding rollers. In this way, both the delimbing knives and the feeding rollers achieve a good contact with trees .

According to a fourth embodiment, the tool is a grab and the support elements are grapples. A sufficient contact between grapples and trees is also important when loading trees to avoid that trees fall between the grapples when the grapple is tilted, for example.

For a grab, the reaction bar can be fastened to a pivot arm, which can be an extension to the grapple, formed in each grapple .

The object of a forest machine according to the invention can be achieved with a forest machine which includes any of the aforementioned embodiments of the tool according to the invention .

The invention, which is not restricted to the embodiments presented below, is described in more detail by making reference to the enclosed drawings, in which:

Figure 1 is an axonometric lateral view of a prior art harvester head in the vertical position with the feeding rollers open,

Figure 2a is a partially cross-sectional view of a prior art tool in the direction of trees with trees of uniform sizes supported by feeding rollers,

Figure 2b illustrates a prior art tool of Figure 2a with trees of different sizes supported by feeding rollers,

Figure 3 is an axonometric lateral view of a harvester head in the horizontal position with the feeding rollers open,

Figure 4 illustrates a harvester head in the direction of a tree with the feeding rollers open,

Figure 5a is a partially cross-sectional view of a tool according to the invention with trees of different sizes supported by feeding rollers with the articulation in one extreme position,

Figure 5b is a partially cross-sectional view of a tool according to the invention with trees of different sizes supported by feeding rollers with the articulation in the other extreme position,

Figure 6a is an axonometric view of a reaction bar separated,

Figure 6b is an axonometric exploded view of a reaction bar separated,

Figure 7 is a lateral view of a reaction bar,

Figure 8 is an axonometric exploded view of a reaction bar according to another embodiment separated, Figure 9 is an axonometric view of delimbing knives separated,

Figure 10 is an axonometric view of a grab as a tool , Figure 11 illustrates a forest machine according to the invention,

Figure 12 is a lateral view of a tool according to the invention also showing the fastening of a reaction bar and an actuator to the frame of a support element .

In the figures, reference is made to the different parts of the invention using the following reference numbers:

10 tool 40a alternative extreme

11 tree 35 position of pivot pin

12 suspension bracket 42 pivot point

16 frame 44 limiter 18 support elements 46 cutting device

20 actuator 48 feeding rollers

22 support arm 40 50 locking devices

24 pivot arm 52 harvester head

26 reaction bar 54 delimbing knife 27 lugs of reaction bar 56 support arm pivot point

28 first end 58 jaw

30 second end 45 60 flange

32 articulation 62 pin hole

34 opening 64 grease nipple 35 eccentric element 65 second opening

36 sleeve 66 pivot bushing

38 pivot bushing 50 68 grease nipple

40 pivot pin 70 bolt

72 locking bolt 74 locking hole 86 grapples

76 projection 90 recess

78 recess 92 limiting projection

80 forest machine 10 94 outer edge of eccentric 82 crane element .

84 grab

Figures 3 to 5b illustrate an advantageous embodiment of a tool according to the invention, wherein the tool is a harvester head 52, which is preferably used suspended to the crane 82 of a forest machine 80 shown in Figure 11 by means of a suspension bracket 12 of Figures 3 to 5b. Although the principle of operation of the invention is described referring to a harvester head and feeding rollers that function as support elements and their support arms, it will be recognised by those skilled in the art that the invention can also be utilised in delimbing knives 54 of a harvester head shown in Figure 9 and in a grab 84 shown in Figure 10 for synchronising grapples 86 by using a reaction bar 26.

Although an embodiment is always described, by making reference to the figures, wherein the articulation between the reaction bar and the support arm of the support element is implemented in such a way that the eccentric element is arranged as part of the reaction bar, a pivot bushing is included in the support arm of the support element and a pivot bushing is provided between these, it will be recognised by those skilled in the art that the invention can also be implemented in another way. In an alternative embodiment, the eccentric element may be arranged in the support arm. Furthermore, the pivot pin can be either a separate part arranged between the pivot bushings of the articulation or it can be an integral part of that part of the reaction bar and the support arm which is without an eccentric element, or an integral part of the eccentric element .

According to Figures 3 and 4, the harvester head 52 functioning as the tool 10 includes a frame 16 and support elements 18 articulated to the frame 16, consisting of feeding rollers 48 and support arms 22 in the harvester head 52 of Figures 3 and 4. In addition, the harvester head 52 includes a reaction bar 26 according to the invention, shown better in Figures 5a and 5b, connecting the support elements 18 preferably by the support arms 22. In addition, the harvester head 52 includes an actuator 20 articulated between the frame 16 and the support arms 22 for rotating the support arms 22 around their pivot points 56 shown in Figures 5a and 5b. One or two actuators can be provided. Figure 4 illustrates the use of two actuators 20, where the actuators are supported each according to Figures 5a to 5b, if the actuator is a cylinder. When using only one actuator, the actuator is articulated directly between two support arms 22. Furthermore, the harvester head 52 generally also includes a cutting device 46 and delimbing knives 54, the synchronisation of which can also be performed with a reaction bar according to the invention.

Figures 5a and 5b illustrate, in a partially cross-sectional view, a situation in which the advantage of the tool 10 according to the invention is achieved. In this situation, there are two trees 11 of different sizes in the jaw 58 formed in the harvester head 52 between the frame 16 and the feeding rollers 48. Regardless of the different diameter of the trees, both feeding rollers 48 are in tight contact with the trees 11. This is achieved with a reaction bar 26 according to the invention, articulated to the support arm 22 of the feeding roller 48 by means of an articulation 32. The articulation 32, which includes pivot bushings 38, 66 in the support arm 22 and in the reaction bar 26, a pivot pin 40 and an eccentric element 35, enable a movement of the pivot point 42 formed between the first end 28 of the reaction bar 26 and the support arm 22. The eccentric element is henceforth referred to as a sleeve. Alternatively, in the case of Figures 5a and 5b, the pivot point 42 can be formed in the support arm 22 between the pivot arm 24 fastened to the other side of the pivot point 56 of the support arm 22 and the first end 28 of the reaction bar 26. Figures 5a and 5b illustrate an additional movement of the support elements between two extreme positions of the sleeve of the articulation enabled by the articulation. More specifically, the force provided by the actuator with which the support arm 22 is rotated around the pivot point 56.

According to Figure 6b, the reaction bar 26 includes a first end 28 and a second end 30, between which the structure of the reaction bar 26 is preferably curved to avoid that the reaction bar 26 limits the space in the jaw of the harvester head. In different applications, the shape of the reaction bar can also be different, such as straight in Figure 10. Arranged at the first end 28 of the reaction bar 26, there is an opening 34, to which the sleeve 36 functioning as the eccentric element is fitted. In turn, a pivot bushing 38 is eccentrically formed in the sleeve 36 enabling the movement of the pivot pin 40 arranged through the pivot bushing by rotating the sleeve 36 to different distances from the second end 30 of the reaction bar 26 that is fixedly articulated to the opposite support arm. Figure 7 depicts the pivot pin 40 and its alternative extreme position with broken lines represented by reference number 40a. The second end 30 of the reaction bar 26 preferably includes a second opening 65, which is essentially parallel with the opening at the first end 28. Advantageously, the sleeve 36 is locked to the opening 34 with two flanges 60 having a pin hole 62, also shown in Figure 6b, which corresponds to the trajectory of the pivot pin machined in at least one of them. Advantageously, the pin hole 62 includes, according to Figure 7, a straight surface 41 and a curved surface 43, of which said 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 towards the smaller tree. The flanges 60 can be fastened with bolts 70, for example, to the side of the reaction bar 26. The flanges 60 may include, according to Figure 6b, a projection 76 extending from their main shape, for which there is also a recess 78 made in the reaction bar 26 with a corresponding shape. This prevents the rotation of the flanges.

The eccentricity, or offset, of the pivot bushing in the sleeve can be, for example, 10 mm from the centre point of the sleeve for a sleeve with a diameter of 80 mm, in which case the displacement of the pivot point achieved during the rotation of the sleeve is 20 mm. More generally, the eccentricity of the sleeve can be between 5% and 45% of the sleeve diameter, however, so that the wall thickness between the outer edge of the sleeve and the pivot bushing is at least 4 mm but not exceeding 30% of the sleeve diameter. The sleeve diameter can be between 40 mm and 160 mm, for example. The amount of eccentricity is determined by the necessary synchronisation deviation of the feeding rollers in order that the feeding roller gets in contact with the smaller tree as well in the jaw. Furthermore, the amount of eccentricity is affected by the dimensioning of the support arms, the reaction bar and the pivot points of the support arms. The aim is to enable a firm contact for a tree that is up to 40% smaller than the bigger tree . The sleeve can be mounted with bearings to the opening of the reaction bar. Alternatively, the sleeve and the opening can also be made of hardened steel, in which case lubrication merely via the grease nipple 64 shown in Figure 6b may be sufficient. In this case, the reaction bar and the flanges are made of wear-resistant steel. Some level of play does not cause problems in this application.

According to Figure 6b, the reaction bar 26 can include locking devices 50 for locking the sleeve 36 non-rotating so that the sleeve is kept in place and movements of the support elements can be fully synchronised when processing trees of essentially a uniform size. In the embodiment of Figure 6b, locking devices 50 consist of a locking bolt 72, which is arranged to move in the radial direction of the sleeve 36 and into a locking hole 74 formed in the sleeve 36 in the radial direction.

Figure 12 is a lateral view showing the articulation of the reaction bar 26 and the actuator 20 to the support arm 22 of the support element 18. According to Figure 12, the reaction bar 26 is fastened to one surface of the support arm 22 by means of the lugs 27 of the reaction bar 26, on an essentially different plane than the pivot arm 24 used for fastening the actuator. In this way, the actuator 20 and the reaction bar 26 do not collide with each other in any situation and the sleeve 36 of the reaction bar 26 enables the movement of the first end 28 of the reaction bar 26 in a curved trajectory.

According to Figure 8, the articulation 32 can also include a limiter 44 for limiting the degree of rotation of the sleeve 36. In an advantageous embodiment shown in Figure 8, the limiter 44 consists of a recess 90 formed in the sleeve following the outer rim of the sleeve and having a rim length below 180° . With such a dimensioning, the recess 90 limits the rotation of the sleeve 36 and prevents the sleeve from rotating to such a position in which its pivot pin settles in a so- called dead centre relative to the force acting on it where force cannot provide the rotation of the sleeve when necessary. The limiter 44 further includes a limiting projection 92 formed in the flange or in the opening 34 at the first end of the reaction bar, extending towards the centre part of the sleeve and arranged to pass through in the groove formed in the sleeve. When the sleeve rotates, the limiting projection collides with the end of the sleeve recess preventing in this way a further rotation of the sleeve.

In an embodiment where the tool is a harvester head, the diameter of the feeding rollers of the harvester head can be between 300 mm and 600 mm, the diameter of the trees processed between 200 mm and 1, 200 mm and the dimension of the reaction bar between 1, 000 mm and 1, 500 mm. In this case, the sleeve diameter can be between 40 mm and 160 mm.