Patent Description:
A tree stump remaining after the felling of a tree may by infected by fungus spores through the air and the resulting fungus growth may cause root rot, which may be transmitted from the infected tree stump to healthy and growing trees in the surroundings via the root system. In order to prevent the development of such root rot in a tree stump, the cut surface of the tree stump may be coated with a suitable treatment liquid in connection with the felling of the tree by means of a tree harvester. The treatment liquid may for instance be a chemical fungicide, such as an urea solution, or a water suspension of spores of harmless fungi which are antagonists or competitors to the harmful fungi. It is previously known to use the saw chain guide bar of a chainsaw cutting device of a tree harvester in order to apply a treatment liquid onto the cut surface of a tree stump by spraying in connection with the felling of a tree. Such a guide bar may for instance be of the type previously known from <CIT> or <CIT> where a liquid feed channel is provided along a part of the guide bar, wherein spray outlet orifices are distributed along the length of the liquid feed channel and a source of treatment liquid is connected to the liquid feed channel in order to supply pressurized treatment liquid into the liquid feed channel and allow the treatment liquid to be emitted through the spray outlet orifices as an array of liquid sprays directed towards the cut surface of a tree stump. With such a saw chain guide bar, the pressure of the treatment liquid drops as the treatment liquid moves through the liquid feed channel and passes the different spray outlet orifices, which may cause an uneven distribution of the treatment liquid over the cut surface of the tree stump.

It is desirable that the exposed cut surface of the tree stump is covered completely and evenly with the treatment liquid. It is also desirable to avoid a spraying of the treatment liquid onto vegetation and ground in the area around the tree stump, to thereby avoid negative environmental effects and a costly waste of treatment liquid. With a saw chain guide bar of the type disclosed in <CIT> or <CIT>, the distribution of the spray outlet orifices along the liquid feed channel has to be adapted to the diameter of the trees to be cut in order to achieve an appropriate spray pattern over the cut surface of the tree stumps. If a saw chain guide bar of this previously known type is adapted for cutting of large diameter trees, a considerable amount of the sprayed treatment liquid will miss the cut surface of a tree stump if the saw chain guide bar is also used for cutting a tree of smaller diameter. If a saw chain guide bar of this previously known type is adapted for cutting of small diameter trees, the sprayed treatment liquid will not cover the entire area of the cut surface of a tree stump if the saw chain guide bar is also used for cutting a tree of larger diameter.

The object of the present invention is to achieve a further development of a saw chain guide bar of the above-mentioned type so as to provide a saw chain guide bar that is improved in at least some aspect.

According to the invention, this object is achieved by means of a saw chain guide bar having the features defined in claim <NUM>.

The saw chain guide bar of the present invention comprises:.

At its upstream end, the liquid feed channel has an inlet opening, through which the liquid feed channel is configured to receive pressurized liquid. At its downstream end, the liquid feed channel has an outlet with at least one spray outlet orifice facing the rear end or the nose end of the guide bar body. This outlet and its spray outlet orifice are in the following referred to as "first outlet" and "first spray outlet orifice", respectively. The first outlet is in fluid communication with the inlet opening of the liquid feed channel and configured to emit liquid received therefrom as a liquid spray through the first spray outlet orifice in a direction towards the rear end of the guide bar body if the first spray outlet orifice faces the rear end of the guide bar body or in a direction towards the nose end of the guide bar body if the first spray outlet orifice faces the nose end of the guide bar body.

The guide bar body is provided with a spray guiding groove, in the following referred to as "first spray guiding groove", formed as an outwardly open elongated recess in the first side face of the guide bar body, wherein the first spray outlet orifice opens into the first spray guiding groove and the first spray guiding groove extends from said first outlet of the liquid feed channel in a direction towards the rear end of the guide bar body if the first spray outlet orifice faces the rear end of the guide bar body or in a direction towards the nose end of the guide bar body if the first spray outlet orifice faces the nose end of the guide bar body.

When liquid is to be applied from the above-mentioned liquid feed channel onto a cut surface of a tree stump, the saw chain guide bar is to be moved across the tree to be felled with the above-mentioned first side face of the guide bar body facing the cut surface of the tree stump. With the saw chain guide bar of the present invention, the above-mentioned spray outlet orifice will emit a liquid spray in a direction along the guide bar body and the associated spray guiding groove will allow this liquid spray to be distributed along the guide bar body before hitting the cut surface of a tree stump. Liquid from one single liquid spray may hereby be distributed over a larger area on a cut surface of a tree stump when the saw chain guide bar is swept over the surface. It is hereby possible to dispense with an arrangement of an array of spray outlet orifices along the length of the liquid feed channel, which in its turn implies that the above-mentioned pressure drop along the liquid feed channel is avoided. With the saw chain guide bar of the present invention, it will also be possible to adjust the reach of the emitted liquid spray by adjustment of the pressure of the liquid supplied to the liquid feed channel, which in its turn makes it possible to adapt the spray pattern in a quick and simple manner in dependence on the diameter of the trees to be cut. The exposed cut surface of the tree stumps may hereby be covered completely and evenly with the sprayed liquid with a limited waste of liquid.

An embodiment of the invention is characterized in:.

In this case, liquid sprays will be emitted from the liquid feed channel in two opposite directions, or at least essentially opposite directions, along the guide bar body, which will ensure an efficient distribution of liquid over a cut surface of a tree stump.

The first outlet preferably has one single first spray outlet orifice and that the second outlet preferably has one single second spray outlet orifice. Furthermore, the first spray outlet orifice and the second spray outlet orifice are preferably aligned with each other.

According to another embodiment of the invention, the total cross-sectional area of all spray outlet orifices of the liquid feed channel is smaller than the cross-sectional area of the inlet opening of the liquid feed channel. Pressure drop in the liquid feed channel is hereby avoided, which is favourable with respect to the formation of the liquid spray or sprays. When the liquid feed channel is provided with one single first outlet orifice and one single second outlet orifice, the sum of the cross-sectional area of the first spray outlet orifice and the cross-sectional area of the second spray outlet orifice is in this case smaller than the cross-sectional area of the inlet opening.

Each spray guiding groove preferably extends in a straight line, or at least essentially straight line, along a part of the first side face of the guide bar body. Furthermore, the first and second spray guiding grooves are preferably aligned with each other.

According to another embodiment of the invention, each spray guiding groove has an inclined bottom surface, which has such an inclination that the depth of the spray guiding groove is gradually decreasing as seen in a direction from a first end of the spray guiding groove facing the associated outlet of the liquid feed channel to an opposite second end of the spray guiding groove.

According to another embodiment of the invention, the liquid feed channel comprises:.

However, the liquid feed channel may of course also be designed in any other suitable manner.

The liquid feed channel is with advantage formed by an elongated tube, which is mounted in an elongated tube-accommodating groove in the first side face of the guide bar body. In this case, a bottom surface of the tube-accommodating groove may have:.

If the above-mentioned elongated tube is an open-ended tube of rather soft metal material, such as aluminium or cupper, and mounted to the tube-accommodating groove in a previously known manner by being pressed into this groove with such a force that the wall of the tube is deformed into a shape essentially corresponding to the shape of the groove, the initially open ends of the tube may be sealed by clamping by being pressed against said ramp sections at the ends of the groove.

Another embodiment of the invention is characterized in:.

In this case, the saw chain guide bar may be attached to the chainsaw cutting device of a tree harvester in a first orientation such that the saw chain guide bar is moved across a tree to be felled with one of the longitudinal edges of the guide bar body as leading edge and with the first side face of the guide bar body facing the cut surface of the tree stump, and in an inverted second orientation such that the saw chain guide bar is moved across a tree to be felled with the other longitudinal edge of the guide bar body as leading edge and with the second side face of the guide bar body facing the cut surface of the tree stump. Thus, when the initial leading edge of the guide bar body becomes worn, the bar may be inverted such that the other longitudinal edge of the guide bar body will become a new leading edge. When the saw chain guide bar is attached to the chainsaw cutting device in said second orientation, liquid may be applied from the above-mentioned additional liquid feed channel onto a cut surface of a tree stump, and when the saw chain guide bar is attached to the chainsaw cutting device in said first orientation, liquid may be applied from the other liquid feed channel onto a cut surface of a tree stump.

Further advantageous features of the saw chain guide bar according to the present invention will appear from the description following below and the dependent claims.

With reference to the appended drawings, a specific description of embodiments of the invention cited as examples follows below.

A saw chain guide bar <NUM> according to a first embodiment of the present invention is illustrated in <FIG>. The saw chain guide bar <NUM> is to be attached to a chainsaw cutting device of a tree harvester and is intended to co-operate with a saw chain of said cutting device. The saw chain guide bar <NUM> comprises an plate-shaped and elongated guide bar body <NUM>, which has a rear end 2b and an opposite nose end 2a. At its rear end 2b, the guide bar body <NUM> has an attachment section <NUM> configured for attachment of the saw chain guide bar <NUM> to a chainsaw cutting device of a tree harvester by clamping. The attachment section <NUM> is in a conventional manner provided with a centre slot <NUM>, which is configured to receive clamping bolts of the chainsaw cutting device. The guide bar body <NUM> has a first side face 5a extending between the rear end 2b and the nose end 2a and an opposite second side face 5b extending between the rear end 2b and the nose end 2a. A first saw chain guide track 6a extends along a first longitudinal edge 7a of the guide bar body <NUM> and a second saw chain guide track 6b extends along the opposite second longitudinal edge 7b of the guide bar body <NUM>. A sprocket wheel <NUM> is in a conventional manner rotatably mounted to the guide bar body <NUM> at the nose end 2a thereof. A saw chain of the above-mentioned cutting device is to extend in a loop around the guide bar body <NUM> along the peripheral edge thereof while being in engagement with the sprocket wheel <NUM> and with the first and second saw chain guide tracks 6a, 6b. During a cutting operation, the saw chain is rotated and thereby driven along the peripheral edge of the guide bar body <NUM> by means of a driving motor of the cutting device.

A liquid feed channel <NUM> extends along a part of the guide bar body <NUM> from the attachment section <NUM> towards the nose end 2a, the liquid feed channel <NUM> having an upstream end 10a located at the attachment section <NUM> and a downstream end 10b located at a distance from the attachment section <NUM>. At its upstream end 10a, the liquid feed channel <NUM> has an inlet opening <NUM>, through which the liquid feed channel is configured to receive pressurized liquid. The liquid is for instance an urea solution or any other desired tree stump treatment liquid and may be supplied to the liquid feed channel <NUM> from a liquid reservoir in the tree harvester by means of a pump.

In the embodiment illustrated in <FIG>, the inlet of the liquid feed channel <NUM> comprises one single inlet opening <NUM>, but the liquid feed channel <NUM> may as an alternative be provided with an inlet that comprises two or more inlet openings.

At its downstream end 10b, the liquid feed channel <NUM> has a first outlet 12a with a first spray outlet orifice 13a facing the nose end 2a of the guide bar body <NUM> and a second outlet 12b with a second spray outlet orifice 13b facing the rear end 2b of the guide bar body <NUM>. The first and second outlets 12a, 12b are located opposite to each other on opposite sides of the liquid feed channel <NUM> and are both in fluid communication with the inlet opening <NUM> in order to receive liquid that has entered the liquid feed channel <NUM> through the inlet opening <NUM>. The first spray outlet orifice 13a is configured to emit liquid from the liquid feed channel <NUM> as a liquid spray in a direction towards the nose end 2a of the guide bar body <NUM> and the second spray outlet orifice 13b is configured to emit liquid from the liquid feed channel <NUM> as a liquid spray in a direction towards the rear end 2b of the guide bar body <NUM>. The first and second spray outlet orifices 13a, 13b are with advantage aligned with each other. Furthermore, the total cross-sectional area of the first and second spray outlet orifices 13a, 13b, i.e. the sum of the cross-sectional area of the first spray outlet orifice 13a and the cross-sectional area of the second spray outlet orifice <NUM>, is preferably smaller than the cross-sectional area of the inlet opening <NUM>.

The guide bar body <NUM> comprises a first spray guiding groove 15a, which is formed as an outwardly open elongated recess in the first side face 5a of the guide bar body <NUM> and which extends from the first outlet 12a of the liquid feed channel <NUM> along a part of the first side face 5a in a direction towards the nose end 2a of the guide bar body <NUM>. The guide bar body <NUM> also comprises a second spray guiding groove 15b, which is formed as an outwardly open elongated recess in the first side face 5a of the guide bar body <NUM> and which extends from the second outlet 12b of the liquid feed channel <NUM> along a part of the first side face 5a in a direction towards the rear end 2b of the guide bar body <NUM>. The first spray outlet orifice 13a opens into the first spray guiding groove 15a and the first spray guiding groove is configured to receive the liquid spray emitted from the first spray outlet orifice 13a and allow this liquid spray to propagate along the length of the first spray guiding groove 15a in a direction towards the nose end 2a of the guide bar body <NUM>. The second spray outlet orifice 13b opens into the second spray guiding groove 15b and the second spray guiding groove is configured to receive the liquid spray emitted from the second spray outlet orifice 13b and allow this liquid spray to propagate along the length of the second spray guiding groove 15b in a direction towards the rear end 2b of the guide bar body <NUM>.

In the illustrated embodiment, each spray guiding groove 15a, 15b extends in a straight line, or at least essentially straight line, along a part of the first side face 5a of the guide bar body <NUM>, wherein the first and second spray guiding grooves 15a, 15b are aligned with each other. However, the first spray guiding groove 15a and/or the second spray guiding groove 15b may as an alternative be slightly curved as seen in the longitudinal direction of the guide bar body <NUM>, as long as it allows the received liquid spray to propagate a certain distance in the longitudinal direction of the guide bar body <NUM>.

Each one of the first and second spray guiding grooves 15a, 15b preferably has a length of <NUM>-<NUM> and a width of <NUM>-<NUM>.

In the illustrated embodiment, each spray guiding groove 15a, 15b has an inclined bottom surface <NUM> (see <FIG> and <FIG>), which has such an inclination that the depth d of the spray guiding groove 15a, 15b is gradually decreasing as seen in a direction from a first end 17a of the spray guiding groove 15a, 15b facing the associated outlet 12a, 12b of the liquid feed channel <NUM> to an opposite second end 17b of the spray guiding groove 15a, 15b. However, each spray guiding groove 15a, 15b may as an alternative have one and the same depth all along its length or a depth that varies in any other suitable manner along the length thereof.

In the illustrated embodiment, the liquid feed channel <NUM> comprises:.

In the illustrated embodiment, the liquid feed channel <NUM> is formed by an elongated tube <NUM> (see <FIG>), which is mounted in an elongated tube-accommodating groove <NUM> (see <FIG>) in the first side face 5a of the guide bar body <NUM>. The tube <NUM> is with advantage mounted to the tube-accommodating groove <NUM> in the manner described in <CIT>, wherein the tube-accommodating groove <NUM> has undercut side walls <NUM>, as illustrated in <FIG>. In this case, the tube <NUM> is made of soft and deformable metal material, such as aluminium or cupper, and is originally made with a circular cross-sectional shape. The tube <NUM> is first bent in correspondence with the longitudinal shape of the tube-accommodating groove <NUM> and then positioned in this groove. After having been inserted into the tube-accommodating groove <NUM>, the tube <NUM> is deformed by rolling or pressing until it fills the tube-accommodating groove <NUM> and conforms to the undercut side walls <NUM> thereof. The tube <NUM> is secured in the tube-accommodating groove <NUM> by having its cross-sectional shape deformed to conform to the undercut cross-sectional shape of the tube-accommodating groove. However, a channel-forming tube may of course also be secured to an associated tube-accommodating groove <NUM> in the guide bar body <NUM> in any other suitable manner. As a further alternative, the liquid feed channel <NUM> may be formed as an integrated part of the guide bar body <NUM>, for instance by being formed as an outwardly covered recess in the guide bar body <NUM>.

In the illustrated embodiment, the bottom surface <NUM> of the tube-accommodating groove <NUM> has:.

When the initially open-ended tube <NUM> is pressed against the bottom surface <NUM> of the tube-accommodating groove <NUM> in connection with the mounting of the tube <NUM> to the guide bar body <NUM>, the end sections 19a, 19b of the tube <NUM> are pressed against a respective one of the ramp sections 23a, 23b such that the end sections 19a, 19b are deformed by clamping against the ramp sections 23a, 23b and thereby sealed. <FIG> illustrates the shape of the tube <NUM> when it has been deformed to conform to the shape of the tube-accommodating groove <NUM>. As an alternative, the ends of the tube <NUM> may be sealed before the mounting thereof in the tube-accommodating groove <NUM>. The inlet opening <NUM> and the spray outlet orifices 13a, 13b may be formed in the tube <NUM> before or after the mounting thereof in the tube-accommodating groove <NUM>.

In the embodiment illustrated in <FIG>, the inlet opening <NUM> of the liquid feed channel <NUM> is facing the bottom surface <NUM> of the tube-accommodating groove <NUM>, wherein the inlet opening <NUM> is aligned with and connected to a liquid supply hole <NUM> that extends through the guide bar body <NUM> between the second side face 5b and the tube-accommodating groove <NUM>. Thus, in this case, the liquid enters the inlet opening <NUM> of the liquid feed channel <NUM> from the second side face 5b of the guide bar body <NUM> through the liquid supply hole <NUM>. However, the inlet opening <NUM> of the liquid feed channel <NUM> may as an alternative be arranged on the outwardly facing side of the liquid feed channel <NUM>, as illustrated in <FIG>. In the latter case, the liquid enters the inlet opening <NUM> of the liquid feed channel <NUM> from the first side face 5a of the guide bar body <NUM>.

In the embodiment illustrated in <FIG>, the first outlet 12a of the liquid feed channel <NUM> comprises one single outlet orifice 13a, but the first outlet 12a may as an alternative be provided with two or more outlet orifices 13a facing the nose end 2a of the guide bar body <NUM>. In the embodiment illustrated in <FIG>, also the second outlet 12b of the liquid feed channel <NUM> comprises one single outlet orifice 13b, but the second outlet 12b may as an alternative be provided with two or more outlet orifices 13b facing the rear end 2b of the guide bar body <NUM>.

In the illustrated embodiment, the saw chain guide bar <NUM> has a liquid feed channel <NUM> with two opposite outlets 12a, 12b and two associated spray guiding grooves 15a, 15b. However, the saw chain guide bar <NUM> may as an alternative have a liquid feed channel <NUM> with one single outlet comprising a spray outlet orifice facing the rear end 2b or the nose end 2a of the guide bar body <NUM> and one single spray guiding groove. If the spray outlet orifice of this single outlet faces the rear end 2b of the guide bar body <NUM>, it is configured to emit liquid from the liquid feed channel <NUM> as a liquid spray in a direction towards the rear end 2b of the guide bar body <NUM>, wherein the associated spray guiding groove extends from the outlet in a direction towards the rear end 2b of the guide bar body <NUM>. If the spray outlet orifice of said single outlet faces the nose end 2a of the guide bar body <NUM>, it is configured to emit liquid from the liquid feed channel <NUM> as a liquid spray in a direction towards the nose end 2a of the guide bar body <NUM>, wherein the associated spray guiding groove extends from the outlet in a direction towards the nose end 2a of the guide bar body <NUM>.

In the embodiment illustrated in <FIG>, the saw chain guide bar <NUM> comprises a first liquid feed channel <NUM> of the type described above for emitting liquid sprays on the first side face 5a of the guide bar body <NUM> and an additional second liquid feed channel <NUM>' of the same type for emitting liquid sprays on the opposite second side face 5b of the guide bar body <NUM>. In this case, first and second spray guiding grooves 15a, 15b are formed as outwardly open elongated recesses in the first side face 5a of the guide bar body <NUM> as described above with reference to <FIG>, whereas corresponding third and fourth spray guiding grooves 15c, 15d are formed as outwardly open elongated recesses in the second side face 5b of the guide bar body <NUM>. As to the rest, the saw chain guide bar <NUM> illustrated in <FIG> corresponds to the saw chain guide bar <NUM> described above with reference to <FIG>. In this case, the saw chain guide bar <NUM> preferably has <NUM>° rotational symmetry about a longitudinal centre axis <NUM> of the guide bar body <NUM>.

In the embodiment illustrated in <FIG>, the first and second spray guiding grooves 15a, 15b are located on the first side face 5a of the guide bar body <NUM> adjacent to the first longitudinal edge 7a thereof, whereas the third and fourth spray guiding grooves 15c, 15d are located on the second side face 5b of the guide bar body <NUM> adjacent to the second longitudinal edge 7b thereof.

In the illustrated embodiments, the guide bar body <NUM> has the form of a solid body. However, the guide bar body <NUM> may as an alternative have the form of a laminated body formed by two or more separate plates.

Claim 1:
A saw chain guide bar comprising:
- an elongated guide bar body (<NUM>), which has a rear end (2b) and an opposite nose end (2a), wherein the guide bar body (<NUM>) at its rear end (2b) has an attachment section (<NUM>) configured for attachment to a chainsaw cutting device of a tree harvester and wherein the guide bar body (<NUM>) has a first side face (5a) extending between the rear end (2b) and the nose end (2a) and an opposite second side face (5b) extending between the rear end (2b) and the nose end (2a); and
- a liquid feed channel (<NUM>) extending along a part of the guide bar body (<NUM>) from the attachment section (<NUM>) towards the nose end (2a), the liquid feed channel (<NUM>) having an upstream end (10a) located at the attachment section (<NUM>) and a downstream end (10b) located at a distance from the attachment section (<NUM>), wherein the liquid feed channel (<NUM>) at its upstream end (10a) has an inlet opening (<NUM>), through which the liquid feed channel (<NUM>) is configured to receive pressurized liquid,
characterized in:
- that the liquid feed channel (<NUM>) at its downstream end (10b) has a first outlet (12a) with at least one first spray outlet orifice (13a) facing the nose end (2a) or the rear end (2b) of the guide bar body (<NUM>), wherein this first outlet (12a) is in fluid communication with the inlet opening (<NUM>) and configured to emit liquid received therefrom as a liquid spray through said at least one first spray outlet orifice (13a) in a direction towards the nose end (2a) of the guide bar body (<NUM>) if said at least one first spray outlet orifice (13a) faces the nose end (2a) or in a direction towards the rear end (2b) of the guide bar body (<NUM>) if said at least one first spray outlet orifice (13a) faces the rear end (2b); and
- that the guide bar body (<NUM>) is provided with a first spray guiding groove (15a) formed as an outwardly open elongated recess in the first side face (5a) of the guide bar body (<NUM>), wherein said at least one first spray outlet orifice (13a) opens into the first spray guiding groove (15a) and the first spray guiding groove (15a) extends from said first outlet (12a) of the liquid feed channel (<NUM>) in a direction towards the nose end (2a) of the guide bar body (<NUM>) if said at least one first spray outlet orifice (13a) faces the nose end (2a) or in a direction towards the rear end (2b) of the guide bar body (<NUM>) if said at least one first spray outlet orifice (13a) faces the rear end (2b).