| 1. | A saw guide bar arrangement (4) adapted for an endless saw chain and consisting of a guide bar (40) that includes edgerelated grooves (42,43) for ac commodating the saw chain, and mutually opposing planar side surfaces (44, 44a), where one of the surfaces, a stumpproximal surface (44), includes a groove (45) in which there is placed a perforated device (46) through which fungicidal liq uid (50) is intended to form, during a cutting operation, a layer over a cut surface of the stump formed during the cutting cycle, characterized in that said perforated device is comprised of a strip (46) which extends along the guide bar (40); in that said groove (45) has edgerelated support surfaces (45a, 45b) adapted for co action with strip portions close to the edge of said strip; and in that the depth at which the support surfaces are orientated in the guide bar (40) exceeds the thick ness of the strip. |
| 2. | An arrangement according to claim 1, characterized in that the ratio of the depth of the support surface to the strip thickness is between 2 and 1,1. |
| 3. | An arrangement according to claim 1, characterized in that the strip is made from a material that is resistant to the fungicidal liquid, such as Bakelite. |
| 4. | An arrangement according to claim 1, characterized in that the groove width allocated to the saw chain is slightly greater than the thickness of the guide bar, within a range of 26 mm. |
| 5. | An arrangement according to claim 1, characterized in that said groove has a crosssectional area of between 10 and 25 mm2, such as about 15 mm2. |
| 6. | An arrangement according to claim 1, characterized in that said strip is affixed to said support surface by means of glue or some similar substance. |
| 7. | An arrangement according to claim 1, characterized in that said holes have a diameter of 0.5 to 2 mm, such as 0.81.2 mm. 8. |
| 8. | An arrangement according to claim 1, characterized in that the distance between respective holes is between 5 and 20 mm, such as 812 mm. |
| 9. | An arrangement according to claim 1, characterized in that said groove has a straight centre portion and angled, straight side portions. |
The saw guide bar arrangement of the kind concerned is comprised gen- erally of a guide bar, or guide plate, that has a saw-chain adapted edge-related groove and mutually opposing planar side surfaces.
One of these surfaces, the surface that lies proximal to the upper surface of the stump formed during a tree cutting cycle includes a recess or groove in which there is placed a perforated device through which a fungicidal liquid can be dispersed over the cut surface of a tree stump formed during a tree cutting cycle, e. g. a spruce cutting cycle.
Description of the background art Several different types of saw blade guide bar arrangements of the afore- said kind are known to the art, not only for the particular application mentioned above, but also for other applications.
For instance, there is known a saw blade guide arrangement in which the actual guide bar, or guide plate, is provided with one or more channels through which an oil lubricant can be delivered to the endless saw chain.
Prior Patent Publications AT-B-401 251 and US-A-5,669,140 can be men- tioned by way of an example of documents that disclose the present standpoint of techniques.
There is also known to the art a saw blade guide bar arrangement in which the guide bar, or guide plate, is designed to accommodate narrow-bore hoses or pipes through which one or more different available colorants can be sprayed onto the cut surface or surfaces formed during said cutting cycle.
Reference is made to prior publication SE-C2-510 751 as an example of the present standpoint of techniques.
Patent Publications WO-A1-90/07870 and US-A-5,797,187 are of interest
in this field of application.
The present invention is founded, more particularly, on a saw blade guide bar arrangement in which one of two planar side surfaces, i. e. the surface that lies proximal to the tree stump, includes a recess or groove in which there is placed a perforated device through which fungicidal liquid can be dispersed during a tree cutting cycle over the cut surface of the stump formed during said cycle.
The need to coat the cut surface of the stump with a fungicidal liquid is based on the insight that the presence of such a liquid will prevent fungi and fungal spores from fastening to the upwardly facing cut surface of the stump.
It has been found that certain fungal spores in a spruce community have the tendency to penetrate down into the root system of the stump and therewith contribute towards the development of root decay.
One particular problem is that these fungal spores are not restricted solely to the tree stump and its root system, but also spread over a relatively wide area in the vicinity of the stump, wherewith said spores tend to attack newly planted trees or saplings in the area and therewith cause early decay in a growing forest.
Earlier known guide bar arrangements of the kind intended here for dis- persing fungicidal liquid (such as UREA (N)) are based on providing on one of the side surfaces of the guide bar, the surface that lies proximal to the stump surface, with a recess or groove in which there is placed a perforated device, a plastic hose having a cross-sectional area in the order of 3 mm2, wherein fungicidal liquid is forced through the perforations.
The perforated device, in the form of a plastic hose, has been found to cause difficulties with respect to the precision in which the perforations, or holes, are formed. Moreover, a fungicidal liquid introduced into the plastic hose tends to thicken and therewith contribute towards successive sealing or clogging of the per- forations.
The construction of the perforated device used conforms to the construc- tion shown and described in Patent Publication US-A-5,669,140, although with the hose inserted in the recess so that the perforations face outwards.
The subject matter of the following patent publications is also relevant to the present standpoint of techniques:
J P-6 087 101 According to the English language translation of this prior publication, there is shown and described a guide plate arrangement which is intended to en- able satisfactory oiling and lubrication during operation, by providing enlarged lu- bricant passageways.
There is particularly proposed the formation of discrete openings or re- cesses (22) which are disposed on at least one side surface of a guide bar or guide plate (4).
Each of these openings is covered by a lid (13) which includes a number of holes (17) disposed in a row for the passage of oil.
Mutually adjacent openings (22) in the guide plate are in mutual co-action through the medium of a narrow groove.
A channel-forming cover strip or cover plate (23) is inserted into the groove and co-acts with adjacent recesses (22) such as to form a channel or pas- sageway (18) between the openings (22) for the passage of oil or lubricant.
Should the lubricant passage (18) become clogged, it can be readily cleaned by removing the cover strip or cover plate (23).
Magnification of the Figs. 2 and 3 shows construction design instructions that may be significant to assessing the patentability of the present invention.
As will be seen from Fig. 2, each of the lids (13) is provided with a sur- rounding edge (13a) orientated at right angles to the planar surface (13b) of the lid (13), said edge (13a) merging with an inner bevelled edge-portion (13c).
This bevelled edge portion (13c) is adapted for direct co-action with a cor- responding bevelled edge-portion (13c') orientated around the opening (22) in the guide plate (4).
The drawing of Fig. 2 therewith gives no directive other than that the bev- elled edge-portions (13c ; 13c') lie in abutment with each other when the lid (13) co-acts with the opening (22), whereas the surface (13b) will be spaced from the planar surface (4b) of the guide plate by a distance corresponding to the thickness ("a") of the surrounding edge (13a).
Figure 3 tends to give the impression that there is only one bevelled edge- portion (16), which is thought to be the most suitable.
However, the bevelled edge portions must co-act with each other in order for these various interpretations to apply.
US-A-5. 035, 058 This document illustrates a saw blade guide bar construction that includes mutually opposing planar surfaces.
The publication also refers to the formation of a number of recesses in one side surface and a number of recesses in the other side surface.
At least some of the recesses are filled with a porous material and some of the recesses can function as an oil reservoir and an oil passageway.
The recesses, or cut-outs, are formed with the intention of obtaining a guide plate construction that is lighter than an homogenous structure.
SE-C2-504 909 This prior publication teaches a colour marking arrangement in the guide bar of a multi-process machine, said arrangement including a guide bar (1) having holders (6,7) and a pipe system (4) adapted to the guide bar.
The pipe system (4) is formed as a component (4,9,10) separate from the guide bar and is designed to be placed in the guide bar in a space intended to this end.
Summary of the present invention Technical problems When taking into consideration the technical deliberations that a person skilled in this particular must make in order to provide a solution to one or more technical problems that he/she encounters, it will be seen that it is necessary ini- tially to realise the measures and/or the sequence of measures that must be un- dertaken to this end on the one hand, and to realise which means is/are required in solving one or more of said problems on the other hand. On this basis, it will be evident that the technical problems listed below are highly relevant to the devel- opment of the present invention.
When studying the present standpoint of techniques, as described above, it will be seen that a technical problem resides in the provision of conditions, with the aid of simple means, that will enable a fungicidal liquid to be dispersed during a tree cutting cycle through the medium of precisely formed holes and the mutual
distribution of said holes, among other things, and therewith to readily distribute said liquid over the entire cut surface of the stump or at least over essentially the whole of said surface.
With respect to a saw blade guide bar arrangement of the aforedescribed nature and intended for the application mentioned, it will be seen that a technical problem resides in the provision of conditions which enable the perforated device to be made of a material that affords resistance to thickening of the fungicidal liq- uid, such that the perforations or holes will remain open even when a long time passes between the cutting cycles that shall form the stump-associated cutting surfaces.
Another technical problem is one of realising the significance of and the advantages associated with forming said perforated device from a thin elongate strip.
Another technical problem is one of realising the significance of allowing said recess to have edge-related support surfaces that are adapted for co-action with edge-proximal portions of the strip.
Yet another technical problem is one of realising the significance of and the advantages afforded by allowing said support surface to be located at a depth which is greater than the thickness of the strip.
Another technical problem is one of realising the significance of and the advantages associated with adapting said depth so as to enable the resultant re- cess or groove to contribute towards turbulent distribution and disintegration of the fungicidal liquid over the exposed upper surface of the stump.
A further technical problem is one of realising the significance of and the advantages afforded by allowing the ratio of support-surface depth to strip thick- ness to lie between 2 and 1.1.
Still another technical problem is one of realising the significance of and the advantages associated with allowing the strip to be made from a material that has properties resistant to the fungicide liquid, such as Bakelite.
Another technical problem is one of realising the significance of and the advantages associated with adapting the groove width allocated to the saw chain to a size which is slightly greater than the thickness of the guide bar or guide plate, such as a thickness in the range of 2-6 mm, such as about 3 mm.
Another technical problem is one of realising the significance of and the
advantages associated with giving the groove an adapted cross-sectional area, such as an area of between 10 and 25 mm2, for instance about 15 mm2.
Another technical problem is one of realising the significance of and the advantages associated with fastening said strip to said side surfaces with the aid of an adhesive layer, such as a glue layer or some similar layer.
Yet another technical problem is one of realising the significance of and the advantages associated with giving the holes or perforations a size which, among other things, is dependent on the distance between said holes, such as a diameter or cross-dimension of 0.5 to 2 mm, for instance a diameter of 0.8-1.2 mm.
Another technical problem is one of realising the significance of and the advantages that are gained by spacing said holes apart at a distance which relates to different criteria, such as a distance of 5-20 mm, for instance 8-12 mm.
Still another technical problem is one of realising the significance of and the advantages that are gained by forming in the guide bar a groove that has a straight centre portion and angled from straight side-portions so as to follow the peripheral edge of the guide bar or guide plate.
Solution The present invention takes as its starting point a saw blade guide bar arrangement adapted for an endless saw chain and comprising a guide bar or guide plate that has an edge-related groove adapted for the saw chain and mutually opposing planar side surfaces of which one, a stump-proximal surface, is provided with a groove or recess in which there is placed a perforated device through which, during a tree cutting cycle, a fungicidal liquid can be dispersed over a cut surface of the stump formed during said tree cutting cycle.
With the intention of solving one or more of the aforesaid technical prob- lems, it is proposed in accordance with the invention that the perforated device shall have the form of a strip, and that said groove shall have edge-related support surfaces adapted for co-action with edge-proximal portions of the strip, and that the depth of the support surfaces in the guide bar exceeds the thickness of the strip.
By way of referred embodiments lying within the scope of the inventive concept, it is proposed that said support surfaces shall be located at a depth that
exceeds the thickness of the strip, and that the ratio of the depth of said support surface to the thickness of the strip will preferably be chosen to lie between 2 and 1. 1.
It is also proposed that the strip is made of a material that has properties resistant to the fungicidal liquid, such as Bakelite.
It is also proposed in accordance with the invention that the groove width allocated to the saw chain is only slightly larger than the thickness of the guide bar or guide plate, within a range of 2-6 mm.
According to one embodiment of the invention, the groove has a cross- sectional area of between 10 and 25 mm2, such as about 15 mm2.
It is also proposed that the perforated strip is affixed to said support sur- faces by means of an adhesive layer, such as a glue layer or a layer of some simi- lar material.
It is also proposed that said holes are preferably given a diameter of 0.5 to 2 mm, such as a diameter of 0.8-1.2 mm.
It is also proposed that the holes are spaced apart at a distance of 5-20 mm, such as 8-12 mm.
It is also proposed that said groove is comprised of a straight central por- tion and angled, straight side portions.
Advantages Those advantages associated with an inventive saw blade guide bar ar- rangement with which a fungicidal liquid is dispersed over the cut surface of a tree stump formed during a tree cutting cycle reside primarily in the provision of meas- ures for dispersing the liquid over the entire cut surface with the aid of a perforated device, an elongate strip, having small well-defined holes, such as drilled holes, and selective distribution of said holes, and by placing the support surfaces in the guide bar at a depth which exceeds the thickness of the strip, such as to form a free space within which the liquid can disperse.
The primary characteristic features of an inventive guide bar arrangement adapted for an endless saw chain are set forth in the characterising clause of the accompanying claim 1.
Brief description of the drawings An embodiment at present preferred of a saw guide bar or plate adapted for an endless saw chain and having features significant of the present invention will now be described by way of example with reference to the accompanying drawings, in which Figure 1 is a side view of a forest harvester with which there is used a saw guide bar arrangement according to the invention; Figure 2 is a side view of a trunk-gripping arrangement, and shows a cross- cut kerf made by a saw chain beneath said gripping arrangement; Figure 3 is a perspective view of a tree stump with the upwardly facing cut surface exposed; Figure 4 is a plan view of a first embodiment of a saw guide bar arrangement; Figure 5 is a plan view of a second saw guide bar arrangement; Figure 6 is a sectioned view taken through the saw guide bar in the proximity of a groove and a perforated strip affixed thereto; and Figure 7 is a sectioned view of a saw guide bar and saw chain in the process of making a cross-cut kerf through the trunk of a spruce.
Description of embodiments at present preferred With the primary intention of clarifying the inventive concept, special ter- minology has been used in the following description of an embodiment which is at present preferred and which has characteristic features significant of the invention and which is illustrated clearly in the figures of the accompanying drawings.
It will be understood, however, that the expressions used in this regard are not limited solely to the terms chosen and that each chosen term shall be inter- preted as including all technical equivalents that function in the same or in essen- tially the same way so as to be able to achieve the same or essentially the same intention and/or technical effect.
Figure 1 is a side view of a forest harvester 1 which includes manoeuvra- ble arms 2 that carry at their outer end 2a a gripping arrangement 3 and a saw chain arrangement 4 disposed beneath the gripping arrangement 3.
Figure 1 also shows a tree 5, a spruce, which has been cut to leave a stump 7.
Figure 2 illustrates how the gripping arrangement 3 is adapted to firmly
grip a tree trunk, a spruce trunk 5. The figure also shows a cut surface 5a and cut surface 7a formed respectively on the trunk and the stump by the saw chain ar- rangement 4, and also the stump 7 that remains after cutting through the trunk.
The stump 7 is shown in perspective in Fig. 3, from which the top surface cut 7a on the stump formed by the cutting cycle can be seen.
Figure 4 is a plan view of a saw blade guide bar arrangement 40 adapted for an endless saw chain (not shown) and comprising a saw guide bar 41 that in- cludes a saw chain-adapted and edge-related grooves 42,43 and mutually oppos- ing planar side surfaces 44,44a, of which the surface 44a is hidden from view and constitutes the surface that faces upwards during the tree cutting cycle.
One of these surfaces, the surface referenced 44 that lies proximal to the stump surface, includes a groove or recess 45 in which there is accommodated a device 46 that includes holes or perforations 47 through which a liquid fungicide is intended to pass during a trunk cutting cycle and to disperse in a layer 8 over the cut surface 7a of the stump formed by the cutting cycle.
As will be seen from Fig. 5, the groove 45'includes a straight centre por- tion 45a and angled, straight side-portions 45b and 45c.
Figure 6 is a sectional view through that part of the saw guide bar ar- rangement 40 which includes the groove or recess 45 and the perforated device 46 that lies sealingly in the groove 45.
In accordance with the invention, the perforated device 46 is comprised of a strip of rectangular cross-section, where the ratio of the width"b"to the thickness "t"of said strip is chosen within the range of 15 to 1, such as between 5 to 1 and 7 to 1.
In the illustrated embodiment, the strip has a thickness"t"of 0.8 and 1.2 mm, such as about 1 mm, and a width"b"of between 10 and 20 mm, such as about 12 mm.
The groove 45 includes edge-related support surfaces 45a, 45b which are adapted for co-action with edge-adjacent portions 46a, 46b of the strip.
The edge-related support surfaces 45a, 45b may have a width of 2 to 4 mm, such as about 3 mm.
The distance of the support surfaces 45a, 45b from the planar side surface 44 is referenced"d"and it will be seen that the support surfaces 45a, 45b are posi- tioned at a distance from the surface 44 that exceeds the thickness of the strip 46,
in other words"d"is slightly greater than"t".
According to the invention, the ratio between the depth"d"of the support surface and the thickness"t"of the strip is between 2 and 1.1.
The strip 46 is made from a material that is resistant to the fungicidal liquid (in other words the material shall not have a catalytic effect that will cause the liq- uid to thicken in and around the perforations). Bakelite, which has been found in practice to have these properties, is particularly proposed in this regard.
A groove width"s"associated with the saw chain is adapted to accommo- date the thickness"e"of the saw guide bar, and it is proposed that a selected dif- ference shall lie in a range of 2-6 mm.
The cross-sectional area of the groove 45 beneath the strip 46 is between 10 and 25 mm2, such as about 15 mm2.
In the illustrated embodiment, the groove or recess has a width"f"of 5 mm and a depth"g"of 3 mm.
The strip 46 is secured to the support surfaces 45a, 45b by means of an adhesive layer 46', such as glue or some corresponding substance.
The holes or perforations 47 have a diameter or cross-section"h"of 0.5 to 2 mm, such as 0.8-1.2 mm, and are either punched or drilled with smooth through- penetrating surfaces. The hole diameter may be 1.0 mm.
The holes are spaced apart by a distance"k"corresponding to between 5 and 20 mm, such as 8-12 mm.
The choice of hole diameter"h", the distance"k"between said holes and the distance between the groove width"s"of the saw chain and the thickness"e" of the saw guide bar are adapted in relation to each other so that at a predeter- mined pressure (generated by means not shown) in respect of the fungicidal liquid 50, said fungicidal liquid will be dispersed at reference 50'and therewith not only cover the stump surface 7a but also form thereon a layer or coating 8 of adapted thickness. The space formed adjacent the strip within the guide bar, or guide plate, and the space adjacent the upper surface of the stump form a turbulence zone for effective distribution of the liquid applied, either in droplet form or in mist form.
When the saw blade guide bar 40 can be swung about a pivot centre dur- ing a tree cutting operation, it may be appropriate to allow the diameter of the holes to vary increasingly towards an increasing swing radius and/or to vary the distance between mutually adjacent holes decreasingly towards an increasing
swing radius, and so on, in order to obtain a layer 8 of essentially constant thick- ness.
The fungicidal liquid 50 is delivered to the groove 45 through a channel (not shown) located at the point of attachment 40a of the saw blade guide bar.
According to one particular embodiment of the present invention, the vol- ume of fungicidal liquid 50 required to form the layer 8 is stored in the groove 45, this volume being sufficient to cover said cutting surface 7a.
The holes 47 are dimensioned so that the fungicidal liquid is unable to leak out via the holes 47, or is unable to leak readily via said holes, as other parts of the spruce trunk, or the trunks of other trees, are cut during the times involved by the cutting cycles.
There is nothing to prevent the inventive saw guide bar arrangement from being provided with further channels for colour marking purposes and thereby fulfil the desideratum.
It will be understood that the invention is not restricted to the described exemplifying embodiment thereof, and that modifications can be made within the scope of the inventive concept as illustrated in the accompanying claims.
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