Firewood splitting apparatus with improved guiding of a saw chain bar in a cutting unit thereof

Abstract

The present invention refers to a firewood splitting apparatus (1) with improved guiding of a saw chain bar (41) in a log cutting unit (4) thereof. An endless saw chain (42) is, when running along the circumference of the saw bar (41), maintained in its tensioned state by means of the saw bar (41), which is properly embedded in a bar holder (7), which is by means of its guides (71',71") guided along the guides (401', 401") on the casing (40) of the cutting unit (4). During operation, a hydraulic media is supplied towards the longitudinal bores (73', 73"), in which pistons (74', 74") are inserted, as well as towards a transversal bore (78), in which a piston (79) is inserted, by which on the one hand additional tensioning of the saw chain (42) can be assured, and on the other hand, clearance within said guides (7T, 71"; 401', 401") is temporarily eliminated. Consequently, the saw bar (41) is prevented from being deflected out from its ideal cutting plane, which could otherwise lead not only to increase of energy consumption for driving of the saw chain (42), but also to overheating and excessive wearing of the saw chain (42) and / or the saw bar (41).

Description

[0001] Firewood splitting apparatus with improved guiding of a saw chain bar in a log cutting unit thereof

[0002] The invention refers to a firewood splitting apparatus with improved guiding of a saw chain bar in a log cutting unit thereof. Such apparatus, among others, comprises a saw unit for cutting of a timber to longitudinal section of a predetermined length, which are then split to separate firewood pieces.

[0003] Such inventions generally belong to working operations in the field of wood processing, in particular to saws for cutting of wood, i.e. to endless chain saws, and in more detail to components of such saws, which serve for tensioning of the endless cutting chain.

[0004] The invention is rest on a problem, how to improve a log cutting unit in a firewood splitting apparatus, so that, in addition to automatic tensioning of an endless saw chain when running along the circumference of a saw bar, namely during operation in heavy duty conditions at high running speed of said saw chain and at relatively high angular speed by pivoting of the casing of the cutting unit around its pivot point, on the one hand a sufficiently intensive additional tensioning of the saw chain shall be assured, and on the other hand also a reliable holding of the saw bar could be achieved by temporarily eliminating the clearance within the guides of the saw bar on the casing of the cutting unit during operation thereof, so that each potential deflection of the saw bar out from its ideal cutting plane due to said clearance could be avoided. A process of cutting logs to separate longitudinal sections of a pre-determined length for the purpose of subsequent splitting such obtained log sections in order to produce firewood pieces is disclosed in DE 10 2009 014 861 Al, where also a cutting unit with an endless saw chain is mentioned. An apparatus, which is suitable for carrying-out such a process, comprises a longitudinally oriented framework, which is on its first end portion furnished with a transporting unit, suitable for resting and forwarding of a complete log prior to cutting thereof, and on its second terminal portion with a splitting unit. Adjacent to the splitting unit there is a splitting chute, and a piston of a pushing cylinder, which is directed towards the splitting unit, protrudes inside of said splitting chute. In the area between said transporting unit and said splitting unit there is a bearing means mounted onto said framework, on which a cutting unit with an endless saw chain is attached, wherein said chain is guided along the circumference of a bar, which is oriented transversely with respect to the longitudinal geometric axis of the framework, and moreover, said bar is pivotal around a geometric axis, which extends in parallel with said longitudinal geometric axis of the framework. Effective length of said bar with the saw chain placed thereon shall exceed a diameter of said log, which is foreseen to be cut to said longitudinal sections, and the cutting unit is pivotal around said geometric axis at a sufficient angle, which during said pivoting of the bar allows cutting of the log across the complete crosssection thereof, upon which each longitudinal log section is split away from the rest of the log.

[0005] A similar apparatus is disclosed in DE 101 07 762 Al and comprises a hydraulically powered cutting unit with an endless saw chain, which is arranged transversely with respect to the longitudinal geometric axis of a corresponding framework and of a log, which is intended for cutting, and is in its pivot point pivotal from its substantially horizontal to its substantially vertical position, or vice versa.

[0006] None of the previously mentioned documents provides any information either about tensioning of the saw chain as such, or about guiding of the saw bar. Whenever the cutting unit is in operation, the saw chain must be properly tensioned, since otherwise disengagement could occur between the saw chain and its guiding groove on the circumference of the saw bar, or also disengagement between the saw chain links and the teeth on the driving chain wheel, which would then unavoidable result in termination of cutting and could also lead to serious mechanical damages on the chain or other components of the cutting unit. Said patent document is also completely silent with respect to accuracy by guiding of the saw bar by pivoting thereof around said geometric axis. In practice, the structure of the wood is never quite homogenous, and wearing of the saw chain can never be completely avoided, so that, in addition to said tensioning forces within the saw chain, additional forces may occur on the saw bar, which may act in various directions and may lead to deflection of the saw bar out from its ideal pivoting plane transversely with respect to the longitudinal axis of the splitting apparatus, which can be visually observed, whenever the front surfaces of the cut- of log section are rough and uneven.

[0007] The cutting unit is during its operation exposed to essential tension stresses, friction and thermal influences, and therefore consequently also to wearing. Thus, a suitable tensioning of the saw chain must be assured due to properly guiding of the saw chain along the guiding groove on the circumference of the saw bar and also throughout the wood as such, so that also the saw bar must be sufficiently resilient and rigid to withstand potential deflections thereof out from the anticipated ideal cutting plane. Namely, wood as such is not a homogenous material, and the forces acting to single cutting edges of the saw chain may essentially vary both with regard to intensity and with regard to acting direction thereof. As long as the saw bar is maintained within its ideal cutting plane, the saw chain is guided properly and is in principle loaded symmetrically with respect to the main plane od the saw bar, so that the forces are transferred from the saw chain towards the saw bar within the main plane thereof. However, as soon as the saw bar is deformed due to bending or torsional stresses and is therefore deflected out from its ideal cutting plane, then essential asymmetric stresses may occur in various directions outside from said main plane of the saw bar, which may lead to local overloads and excessive friction, which leads to excessive energy consumption by simultaneously overheating and wearing of the saw chain and / or saw bar, in particular in the area of the guiding groove on the circumference of the saw bar. Each wearing leads to increasing of clearances between the parts, which makes the situation even worse and worse.

[0008] Moreover, by pivoting of the cutting unit around its pivoting axis, each deflection of the saw bar out from its ideal plane leads to additional loading of the saw bar holder, so that during the time also the accuracy of positioning of the saw bar as such may be jeopardized, which leads to undesired further deviations.

[0009] Some simplified apparatus for cutting of logs to longitudinal sections of a predetermined length by means of a cutting unit with an endless saw chain is disclosed in DE 20 2013 000 344 Ul. The cutting unit is attached onto the framework in a similar manner like in previously discussed solutions, and its deficiencies are practically the same.

[0010] A log cutting and splitting apparatus, which is suitable for producing firewood pieces, is disclosed in EP 2 933 074 Al, where also tensioning of a saw chain in a cutting unit is discussed. Such apparatus comprises a framework, which is suitable for supporting of a splitting assembly located at a suitable distance above the ground surface, and a cutting unit, which is adjusted for cutting of a log in a transversal direction due to obtaining semi-products, namely longitudinal log sections of a pre-determined length, as well as a splitting unit, which is suitable for splitting od each one of said longitudinal log sections in longitudinal direction thereof, wherein said splitting unit comprises a splitting tool and a pushing means as required for splitting by means of said splitting tool. Said cutting unit comprises a casing, a saw chain , a bar for guiding said saw chain, an engine and a driving chain wheel, which is suitable for driving of said saw chain. The saw unit comprises a rail which is attached to the casing of the splitting unit, as well as a base, which is displaceable placed on said rail in such a way that the engine and the driving chain wheel are mounted on said base. The chain wheel is mounted on the driving shaft of the engine, and the cutting unit comprises a means for tensioning of the saw chain.

[0011] In the most of commercially available chain saws, which are used in forestry, the engine is placed within the casing, while the driving chain wheel is mounted on the driving shaft of the engine. The bar is furnished with an elongated centrally arranged opening, through which two screws are inserted, which are spaced apart from each other and by means of which the bar can be pressed towards to the casing in each desired position along said elongated opening, and can be therefore fixed onto the casing. The saw chain, which is placed along the circumference of the bar, can be tensioned by means of displacing of the bar relative to the casing, as soon as said screws have been at least partially released, which means that by tensioning of the saw chain, the distance between the distal portion of the bar and the casing or the driving chain wheel is increasing, until the saw chain is sufficiently tensioned. Upon that, the bar needs to be fixed in such a position. However, during operation of the cutting unit, some extension of the saw chain as such may occur, and in addition to that, some wearing and loosening of engagement between the neighboring chain links may also occur, which leads to inappropriate guiding of the saw chain, so that most critical cases a required engagement between the saw chain and the driving chain wheel, or also between the saw chain and the guide on the bar, may be jeopardized. Besides, also the cutting edges on the saw chain are exposed to intensive wearing, so that from time to time the saw chain must be replaced i.e. exchanged with another properly sharpened saw chain.

[0012] In such case, operation of the cutting unit must be interrupted, which means switching-off the driving engine and releasing the bar, which must then be displaced to another position, upon which the bar need to be fixed in such selected position. This is a time consuming operation, which is however generally feasible, since the operator may by one hand retain the bar with appropriately tensioned saw chain, while by the other hand he can still take care about the screws or similar attaching means, by which the bar is then fixed onto the casing in such selected position.

[0013] Contrary to that, a solution according to EP 2 933 074 Al proposes that the bar should be firmly and fixedly mounted onto the framework of the cutting unit, while the driving chain wheel together with the engine and the belonging casing are mounted on a vase, which is displaceable along a rail in a direction away from the bar, and all these parts are permanently pushed in the said direction by means of a chain tensioning assembly, e.g. by means of a suitable spring. Such approach may lead to certain benefits, like a permanent compensation of wearing, and in addition to that, at least within a pre-determined range also the previously mentioned chain extensions or looseness should be automatically compensated. The problem however arises, whenever the saw chain needs to be replaced. In such case, the operator alone is practically unable to replace the saw chain, and somebody else must assist, who is able to retain the casing with the driving chain wheel against the force of said spring, upon which the operator is able, by his both hands, to remove the saw chain on the one hand from the driving chain wheel, and on the other hand from the guide on the bar, upon which a supplemental saw chain can be placed into the guide on the circumference of the bar and over the driving chain wheel, upon which said retaining of the casing with the engine and the driving chain wheel in the previously mentioned position can be terminated.

[0014] Within the context of such approach, one should bear in mind that operation of a cutting unit on a firewood splitting apparatus, when compared with a classic handoperated cutting of timbers, or common operation of a hand-operated chain saw, is connected with much higher loadings in the area of the bar and the endless saw chain. Namely, due to assuring of a required productivity of a log cutting and firewood splitting apparatus it is usually expected, that the speed of progression of the saw chain over the complete cross-section of the log should be as high as possible. This requirement refers both to velocity of the saw chain as such, and also to angular velocity of pivoting of the casing together with the bar and the saw chain, by which a log can be cut in a shortest possible time along its complete cross-section. In such circumstances, tensioning of the saw chain just by means of a spring, which is in fact capable to maintain the required pre-tensioning of the saw chain prior to operation, is often insufficient for maintaining of a required tensioning of the saw chain during the cutting operation as such. As mentioned, insufficiently tensioned saw chain may lead to serious risk of disengagement between the saw chain and the guide on the bar, or between the saw chain and the driving chain wheel, which results not only in enormous noise and decreasing of effectiveness of the saw chain, but also in extremely increasing of wearing and in most cases also in serious mechanical damages of the saw chain and / or the bar and / or the driving chain wheel.

[0015] The present invention refers to a firewood splitting apparatus with improved guiding of a saw chain bar in a log cutting unit thereof. Such apparatus generally comprises a rigid frame, a transporting unit, which is adjusted for transporting of logs, namely for forwarding of logs one by one in a longitudinal direction of said frame, a cutting unit, which is suitable for successively cutting of each particular log as forwarded by said transporting unit to separate longitudinal sections of a pre-determined length, a splitting unit, which is adjusted for splitting of each cutoff longitudinal section of said log to separate firewood pieces of a roughly predetermined shape and approximately pre-determined dimensions, and moreover, a hydraulic driving assembly, which is suitable for driving of said transporting unit, said cutting unit and said splitting unit.

[0016] Said framework is adjusted for being rest on at least approximately horizontal ground surface and is on its first terminal portion furnished with said transporting unit, which is arranged at a suitable height above the ground surface and is suitable for successively transporting of single logs in the longitudinal direction of said framework, which is defined by longitudinal geometric axis, wherein said framework is on its second terminal portion furnished with said splitting unit, while in the central area of said framework, namely between the transporting unit and the splitting unit, there is a cutting unit attached onto said framework, so that said cutting unit as such is separately and independently on attachment of said transporting unit and said splitting unit mounted onto the framework of the apparatus, and wherein said hydraulic driving assembly is also mounted onto said framework, and moreover, said framework is optionally furnished with a suitable connecting means for establishing a detachable mechanical interconnection between the framework and a tractor or any other vehicle, by means of which the apparatus is transportable to each desired location.

[0017] Furthermore, said transporting unit is conceived as a hydraulically driven belt conveyor, which is adjusted for transporting of a single log, prior to cutting thereof, in a direction along said longitudinal geometric axis of the framework, namely in a direction towards the cutting unit and the splitting unit.

[0018] Still further, said cutting unit is conceived as a motor-driven chain saw, comprising at least a casing, a bar, which is attached to said casing, and an endless cutting chain, which is suitably tensioned and guided along the circumference of said bar by means of a chain wheel, which is placed on a driving shaft, which is driven by means of a hydraulic motor, which is powered by said hydraulic driving assembly. Still further, said cutting unit is mounted on the framework of the apparatus in such a way that the casing of the cutting unit is located outside of a cross-section of each log to be cut, which is defined by the maximal allowable diameter thereof.

[0019] Said casing is, together with the bar, which is attached thereto, and the endless chain, which extends along the circumference of said bar, pivotal around the geometric axis, which extends throughout the pivot point of the casing, over the complete cross-section of the log, the thickness of which is limited by said maximal diameter and which is intended to be cut and after that also split by means of the apparatus, wherein however the effective length of the bar is longer than said allowable maximal diameter of the log, which is to be cut on said apparatus. Moreover, said casing of the cutting unit is, together with the belonging bar and the endless chain, attached to the framework of the apparatus pivotally around the horizontal geometric axis, which extends parallel to the longitudinal geometric axis io of the framework of the apparatus, so that by pivoting of said casing around said geometric axis, the bar is together with the endless chain, which is placed thereon, displaceable from its initial position, namely inactive position, in which it protrudes in approximately vertical direction away from said framework, into its terminal position, in which it in a vertical plane passes transversely across the framework, so that inbetween of these two positions of the bar, the log being intended for cutting and splitting and having a diameter smaller than the maximal allowed diameter, can be transported by means of said transporting unit along the longitudinal geometric axis of the framework. Said cutting unit further comprises a bar holder, to which said bar is reliably attached in a detachable manner and which is furnished with a guide, which is adjusted to cooperate with a guide, which is formed within the casing of the cutting unit, so that said bar holder is by means of said guides displaceable relatively to said casing in a direction along the longitudinal geometric axis of the bar. Still further, said cutting unit comprises a tensioning means, which is intended for tensioning of the endless chain by means of pushing said bar holder together with the bar, which is attached thereto, along said guides in the longitudinal direction of the bar and away from said casing of the cutting unit.

[0020] Still further, said splitting unit of the apparatus comprises a suitable splitting chute, which is adjusted for receiving of a longitudinal log section of a pre-determined length, which is cut-off from the log by means of said cutting unit, and, in addition to said chute, also a splitting tool, a supporting means, and a driving means which is powered by means of said hydraulic driving assembly, so that either a splitting tool is by means of said driving means displaceable in a direction towards the interior of said cut-off log section, which is in such case supported by said supporting means, or said supporting means is displaceable by means of said driving means in a direction towards said log section and along the splitting chute together with the log section also towards the splitting tool.

[0021] Said hydraulic driving assembly is suitable for supplying of so much power to the previously mentioned mechanical units of the apparatus, namely of said transporting unit, said cutting unit and said splitting unit, as required for assuring their functionality, wherein said assembly is either autonomous, or may as such also be energized by a suitable power source, which is available on a tractor or any other vehicle or working apparatus, to which said apparatus is attachable.

[0022] According to the invention, the previously stated technical problem is solved in such a way, that the bar holder, to which the bar is attached in the cutting unit, in addition to said pair of guides, which extend parallel to each other and are arranged in a plane, which extends transversely with respect to the longitudinal axis of the framework of the apparatus, and which are adjusted for sliding along the guides as formed in the casing of the cutting unit as well as for preventing of any movement of said casing together with the bar in a longitudinal direction along the axis of the framework of the apparatus, and in addition to at least two transversal bores, which are adjusted for receiving of attaching means for establishing of a detachable interconnection between the bar holder and the bar, wherein said bores extend parallel with each other and transversely throughout the bar holder, namely in parallel with the geometric axis, around which said casing is pivotal, namely along the geometric axis, which extends in the longitudinal direction of the apparatus, also comprises a further pair of bores, which are spaced apart from each other and extend longitudinally, namely in parallel with said guides, wherein said bores are conceived as hydraulic cylinders, which are, each per se, via suitable hydraulic conduits hydraulically interconnected with the hydraulic driving assembly. In this, each one of said bores is on its side, which is facing towards the bar and towards the framework of the apparatus, blinded by a suitable nipple, and a hydraulic piston is inserted into each one of said bores, such that each hydraulic piston protrudes out of the belonging bore on its side, which is faced away from the bar and the framework of the apparatus, and is moreover adjusted to be rest onto the casing of the cutting unit. Consequently, each piston is displaceable along the belonging bore either by means of a spring, which is inserted within the bore in the area between the piston and the corresponding nipple, or also by means of hydraulic media, which is supplied towards to the interior of the bore through a corresponding hydraulic conduit. Consequently, each piston within the bar holder is by means of the belonging spring permanently pressed with a pre-determined force towards the casing, and when required, said pressing force towards the casing can be still be increased by means of pressurized hydraulic media, which is supplied through said hydraulic conduits. Moreover, the invention proposes that within the bar holder, namely in the area between said longitudinal bores, and also between said transversal bores for receiving of connecting means for establishing of detachable mutual interconnection between the bar and the bar holder, there is a further transversal bore arranged, which extends transversely to the saw bar plane and in parallel with a geometric axis, around which said casing of the cutting unit is pivotal. Said transversal bore is via a belonging hydraulic conduit and together with at least one of the previously mentioned hydraulic conduits hydraulically connectable with the hydraulic driving assembly. A hydraulic piston is inserted within said transversal bore, which protrudes out from said bore and is with its outwardly from said transversal bore protruding terminal portion rest on the casing of the cutting unit, so that due to the pressure of the hydraulic media towards the piston, each guide on the holder of the bar is pressed towards the complementary guide on the casing of the cutting assembly, along which the holder with the bar is displaceable along its longitudinal geometric axis either in a direction towards the casing, or in opposite direction.

[0023] In a preferred embodiment of the invention, said hydraulic interconnection between the said transversal bore, which is acting as a hydraulic cylinder in combination with said piston, and said hydraulic driving assembly is arranged in such manner that supplying of pressurized hydraulic media into the transversal bore is enabled only simultaneously with supplying of pressurized hydraulic media via said hydraulic conduits to said longitudinal bores, in which said pistons, which are rest on the casing of the cutting unit, are inserted together with the belonging springs.

[0024] An embodiment of the invention will be explained in more detail on the basis of the attached drawings, wherein

[0025] Fig. 1 shows a schematically presented firewood splitting apparatus with improved guiding of an endless chain bar in a log cutting unit thereof, in isometric view;

[0026] Fig. 2 shows a log cutting unit in the apparatus according to Fig. 1, which is presented in isometric view and in its first state, in which a saw bar holder is moved away from the pivot point of the saw unit, and the endless saw chain, although pre-tensioned prior to its operation, is during the sawing supplementary tensioned;

[0027] Fig. 3 shows a log cutting unit in the apparatus according to Fig. 1, which is presented in isometric view and in its second state, in which a saw bar holder is moved towards the pivot point of the cutting unit and is temporarily retained by means of an arresting mechanism, so that the endless saw chain is released and could also be replaced, if required;

[0028] Fig. 4 shows a chain bar holder in the apparatus according to Fig. 1, presented in a cross-section along its central longitudinal plane, extending parallel to the dominant surface of the bar as such;

[0029] Fig. 5 shows a log cutting unit according to Fig. 2, presented in front view and in its state, prior to or during the cutting operation, when the endless saw chain is pre-tensioned or supplementary tensioned;

[0030] Fig. 6 shows a log cutting unit according to Fig. 2, again presented in front view, however in another state, in which its arresting mechanism is deactivated, so that, upon removal of the endless saw chain from the bar, even the bar holder could be removed from its guides within the cutting unit casing; and

[0031] Fig. 7 shows a log cutting unit according to Fig. 3, again presented in front view, however in another state, in which the bar holder is displaced towards the pivot point of the cutting unit casing, so that the chain is totally released i.e. not tensioned, while the bar holder is retained in its position by means of said arresting mechanism.

[0032] A firewood splitting apparatus 1 with improved guiding of a chain saw bar 41 with an endless chain 42 in a log cutting unit 4 thereof is schematically and quite in generally presented in Fig. 1. Such apparatus 1 generally comprises a rigid frame 2, a transporting unit 3 adjusted for transporting of logs, namely for forwarding of logs 9 one by one in the longitudinal direction 200 of said frame 2, a cutting unit 4 suitable for successively cutting of each log 9 forwarded by said transporting unit 3 to separate longitudinal sections of a pre-determined length, a splitting unit 5, which is adjusted for splitting of each cut-off longitudinal section of said log 9 to separate firewood pieces of a roughly pre-determined shape and approximately pre-determined dimensions, and moreover, a hydraulic driving assembly 6, which is suitable for driving of said transporting unit 3 and cutting unit 4, as well as of said splitting unit 5.

[0033] Said framework 2 as such is adjusted for being rest on at least approximately horizontal ground surface and is on its first terminal portion 21 furnished with said transporting unit 3, which is arranged at a suitable height above the ground surface and is able to transport each particular log 9 in the longitudinal direction of said framework 2, which is defined by longitudinal geometric axis 200. Moreover, said framework 2 is on its second terminal portion 22 furnished with said splitting unit 5. In addition to that, in the central area 23 of said framework 2, namely between the transporting unit 3 and the splitting unit 5, there is a cutting unit 4 attached onto said framework 2. Said cutting unit 4 as such is separately and quite independently on attachment of said transporting unit 3 and said splitting unit 5 mounted onto the framework 2 of the apparatus 1. Moreover, said hydraulic driving assembly 6 is also adjusted to be mounted onto said framework 2, wherein said framework 2 is optionally also furnished with suitable connecting means for establishing a detachable mechanical interconnection between the framework 2 and a tractor or any other vehicle, by means of which the apparatus 1 can be transported to each desired location.

[0034] In this, said transporting unit 3 is generally conceived as a hydraulically driven belt conveyor, which is adjusted for transporting of a single log 9 prior to cutting thereof in a direction along said longitudinal geometric axis 200 of the framework 2, namely in a direction towards the cutting unit 4 and the splitting unit 5. Still further, said cutting unit 4 is generally a motor-driven chain saw, comprising at least a casing 40, a saw bar 41, which is attached to said casing 40, and an endless cutting chain 42, which is suitably tensioned and guided along the circumference of said bar 41 by means of a chain wheel placed on a driving shaft, which is driven by means of a hydraulic motor, which is powered by said hydraulic driving assembly 6. In this, said cutting unit 4 is mounted on the framework 2 in such a way that the casing 40 of the cutting unit 4 is located outside of a crosssection of each log 9, which is intended to be cut and which is defined by the maximal allowable diameter D thereof, wherein said casing 40 is, together with the saw bar 41, which is attached thereto, and the endless chain 42, which extends along the circumference of said bar 41, pivotal around the geometric axis 400 extending throughout the pivot point of the casing 40 over the complete crosssection of the log 9, the thickness of which is limited by said maximal diameter D and which is intended to be cut and after that also split by means of the apparatus 1, wherein the effective length L of the bar 41 is longer than said allowable maximal diameter D of the log 9, which is to be cut on said apparatus 1. Consequently, said saw unit 4 is able to cut said log 9 along the complete crosssection thereof during a single stroke, namely during a single pivoting of the casing 40 with the saw bar 41 and the endless saw chain 42. Namely, said casing 40 of the cutting unit 4 is, together with the belonging bar 41 and the endless chain 42, attached to the framework 2 of the apparatus pivotally around the horizontal geometric axis 400, which extends parallel to the longitudinal geometric axis 200 of the framework 2 of the apparatus 1 , so that by pivoting of said casing 40 around said geometric axis 400, the bar 41 is together with the endless chain 42 placed thereon displaceable from its initial i.e. inactive position, in which it protrudes in approximately vertical direction away from said framework 2, into its terminal position, in which it in a vertical plane passes transversely across the framework 2, while inbetween of these two positions of the bar 41, the log 9 having maximal diameter D and being intended for cutting and splitting, may be transported along the longitudinal geometric axis 200 of the framework 2 by means of said transporting unit 3. In addition to that, said cutting unit 4 comprises a bar holder 7, to which said bar 41 is attached firmly but in a detachable manner, and which is furnished with a guide 71’, 71”, which is adjusted to cooperate with a guide 401’, 401”, which is formed within the casing 40 of the cutting unit 4, so that said bar holder 7 is by means of said guides 71’, 71 ” ; 401 ’, 401 ” together with the saw bar 41 displaceable relatively to said casing 40 in a direction along the longitudinal geometric axis 410 of the bar 41. Those skilled in the art will understand that a suitable clearance must be assured between each guide 71’, 71” on the bar holder 7 and each corresponding guide 401 ’, 401 ” in the casing 40 of the saw unit 4, which then allows the bar holder 7 to be displaceable relatively to the casing 40 of the saw unit 4. Still further, said cutting unit 4 comprises a tensioning means, which is intended for tensioning of the endless chain 42 by means of pushing said bar holder 7 together with the bar 41 attached there-to along said guides 71’, 71”; 401’, 401” in the longitudinal direction 410 of the bar 41 and away from said casing 40 of the cutting unit 4.

[0035] Said splitting unit 5 of the apparatus 1 according to the invention generally comprises a suitable splitting chute 51, which is adjusted for receiving of a longitudinal log section of a pre-determined length, which has been cut-off from the log 9 by means of said cutting unit 4, and, in addition to said chute 51, also a splitting tool 52, a supporting means 53, as well as a driving means 54 which is energized by said driving assembly 6, so that either a splitting tool 52 is by means of said driving means 54 displaceable in a direction towards the interior of said cut-off log section, which is in such case supported by said supporting means 53, or said supporting means 53 is displaceable by means of said driving means 54 in a direction toward said log section and along the splitting chute 51 together with the log section also towards the splitting tool 52.

[0036] Said hydraulic driving assembly 6 is suitable for supplying such a power to the previously mentioned mechanical units 3, 4, 5 of the apparatus 1, which is required for assuring their functionality, wherein said assembly 6 may either be autonomous, or may as such also be energized by a suitable power source, which may either be available on a tractor or any other vehicle or working apparatus, to which said apparatus 1 is attachable.

[0037] As soon as the apparatus 1 is placed in each desired location and its hydraulic driving assembly 6 is, either by activation of an autonomous hydraulic power unit, or by connecting to a hydraulic system of a tractor or the like, supplied by a required quantity of properly pressurized hydraulic liquid, a log 9 may be loaded onto the transport unit 3. The cutting unit 4 is pivoted to its inactive position, in which the bar 41 is located in approximately vertical position outside of the crosssection area of the log 9. Upon activation of said transporting unit 3, the log 9 is displaced in the longitudinal direction of the apparatus 1, i.e. along said longitudinal geometric axis 200 and is passing below said bar 41 of the cutting unit 4 at a pre-determined distance, which corresponds to the length of firewood pieces, which should be produced by means of cutting and splitting of the log 9. Upon activation of the cutting unit 4, the driving chain wheel starts rotating and forcing the endless chain 42 to slide along the circumference of the bar 42, wherein the chain 42 is already suitably pre-tensioned, upon which the casing 40 of the cutting unit 4 is pivoted together with the bar 41 and the chain 42 placed thereon around said geometric axis 400 in the pivot point of the casing 40, wherein the bar 41 of the cutting unit 4 is gradually pivoted to its approximately horizontal position, by which the log 9 is cut along its entire cross-section area. Such obtained longitudinal section of the log 9 of a pre-determined length is then delivered to said splitting chute 51 of the splitting unit 5, where it is then rest on the supporting means 53 and by means of a suitable splitting tool 52, powered by means of a suitable driving means 54, split to a desired number of firewood pieces of the previously mentioned length. Upon that, such operational sequence can be repeated until the entire log 9 is cut and split, upon which another log 9 may be loaded onto the transporting unit.

[0038] In the sense of the initially exposed technical problem, the invention is merely focused on providing efficient guiding of the saw bar 41 together with the endless saw chain 4, which is displaceable along its circumference, during the cutting operation, namely during pivoting of the saw unit 4 around said geometric axis 400 and the pivot point of the casing 40, when the saw bar 41 together with said saw chain 42 could, due to said clearance within the guides 71’, 71” between the bar holder 7 and the casing 40 of the saw unit 4, or due to insufficiently tensioned saw chain 42, be displaced outside of intended i.e. ideal cutting path, which would then lead to essentially increased power consumption by driving the saw chain 42, by simultaneously overheating of the saw chain 42 and the saw bar 41 and consequently to extensive wearing of the saw chain 42 and guiding groove on the circumference of the saw bar 41, which would essentially shorten the lifetime of the saw chain 42 and / or the saw bar 41.

[0039] To this aim, the invention proposes that said bar holder 7, to which the bar 41 is attached in the cutting unit 4, in addition to said pair of guides 71’, 71”, which extend parallel to each other and are arranged in a plane, which extends transversely with respect to the longitudinal axis 200 of the framework 2 of the apparatus 1, and which are adjusted for sliding along the guides 401’, 401” as formed in the casing 40 of the cutting unit 4 as well as for preventing of any movement of said casing 40 together with the bar 41 in a longitudinal direction along the axis 200 of the framework 2 of the apparatus 1, and in addition to at least two transversal bores 72’, 72”, which are adjusted for receiving of attaching means for establishing of a detachable interconnection between the bar holder 7 and the bar 41, wherein said bores 72’, 72” extend parallel with each other and transversely throughout the bar holder 7, namely in parallel with the geometric axis 400, around which said casing 40 is pivotal, namely along the geometric axis 200, which extends in the longitudinal direction of the apparatus 1, also comprises a further pair of bores 73’, 73”, which are spaced apart from each other and extend longitudinally, namely in parallel with said guides 71’, 71”; 401’, 401, wherein said bores 73’, 73” are conceived as hydraulic cylinders, which are, each per se, via suitable hydraulic conduits 730’, 730” hydraulically interconnected with the hydraulic driving assembly 6. Each one of said bores 73’, 73” is on its side, which is facing towards the saw bar 41 and towards the framework 2 of the apparatus 1, blinded by a suitable nipple 720’, 720”, and a hydraulic piston 74’, 74” is inserted into each one of said bores 73’, 73” such that each hydraulic piston 74’, 74” protrudes out of the belonging bore 73’, 73” on its side, which is faced away from the saw bar 41 and the framework 2 of the apparatus 1 , and is moreover adjusted to be rest onto the casing 40 of the cutting unit 4. Moreover, each one of said pistons 74’, 74” is displaceable along the belonging bore 73’, 73” either by means of a spring 75’, 75”, which is inserted within the bore 73’, 73” in the area between the piston 74’, 74” and the corresponding nipple 720’, 720”, or also by means of hydraulic media, which is supplied towards to the interior of the bore 73’, 73” through a corresponding hydraulic conduit 730’, 730”. Consequently, each piston 74’, 74” within the bar holder 7 is by means of the belonging spring 75’, 75” permanently pressed with a pre-determined force towards the casing 40, and when required, said pressing force towards the casing 40 can be still additionally increased by means of pressurized hydraulic media, which is supplied through said hydraulic conduits 730’, 730”.

[0040] On the other hand, a further transversal bore 78 is arranged within the bar holder 7, namely in the area between said longitudinal bores 73’, 73”, and also between said transversal bores 72’, 72” for receiving of connecting means for establishing of detachable mutual interconnection between the bar 41 and the bar holder 7, a wherein said transversal bore 78 extends transversely to the saw bar 41 plane and in parallel with a geometric axis 400, around which said casing 40 of the cutting unit 4 is pivotal. Also said transversal bore 78 is via a belonging hydraulic conduit 78’ and together with at least one of the said hydraulic conduits 730’, 730” hydraulically connectable with the hydraulic driving assembly 6, and moreover, a hydraulic piston 79 is inserted within said transversal bore 78, which protrudes out from said bore 78 and is with its outwardly from said transversal bore 78 protruding terminal portion rest on the casing 40 of the cutting unit 4. Consequently, due to the pressure of the hydraulic media towards the piston 79, each guide 71 ’, 71” on the holder 7 of the bar 41 is pressed towards the complementary guide 401 ’, 401 ” on the casing 40 of the cutting assembly 4, along which the holder 7 with the bar 41 is displaceable along its longitudinal geometric axis 410 either in a direction towards the casing 40, or in opposite direction.

[0041] In a preferred embodiment of the invention, said hydraulic interconnection between the said transversal bore 78, which is acting as a hydraulic cylinder in combination with said piston 79, and said hydraulic driving assembly 6 is arranged in such manner that supplying of pressurized hydraulic media into the transversal bore 78 is enabled only simultaneously with supplying of pressurized hydraulic media via said hydraulic conduits 730’, 730” to said longitudinal bores 73’, 73”, in which said pistons 74’, 74”, which are rest on the casing 40 of the cutting unit 4, are inserted together with the belonging springs 75’, 75”.

[0042] Operation of the apparatus 1 as such has already been explained. It should be further explained that during the cutting operation, namely by pivoting of the saw assembly around the axis 400 from the initial position towards the terminal position, by which the saw bar 41 together with the chain bar 42 running along its circumference is displaced across the complete cross-section of the log 9, by supplying of the hydraulic media into the longitudinal bores 73’, 73” and also into the transversal bore 78, on the one hand by means of both pistons 74’, 74” the tensioning of the saw chain 42 is temporarily increased, while on the other hand, by means of said piston 79, the clearance within the guides 71’, 7”; 401 ’, 401” between the bar holder 7 and the casing 40 of the saw unit 4 is temporarily eliminated, so that during the cutting stroke the saw chain 42 is additionally tensioned and the saw bar 41 as such is totally immobilized, so that each deflection thereof out of the ideal cutting direction is a priori prevented.

Claims

CLAIMS1. Firewood splitting apparatus (1) with improved guiding of a saw chain bar (41) in a log cutting unit (4) thereof, said apparatus (1) comprising a rigid frame (2), a transporting unit (3) adjusted for transporting of logs (9), namely for forwarding of logs (9) one by one in a longitudinal direction (200) of said frame (2), a cutting unit (4) suitable for successively cutting of each particular log (9) as forwarded by said transporting unit (3) to separate longitudinal sections of a predetermined length, a splitting unit (5), which is adjusted for splitting of each cutoff longitudinal section of said log (9) to separate firewood pieces of a roughly pre-determined shape and approximately pre-determined dimensions, and moreover, a hydraulic driving assembly (6), which is suitable for driving of said transporting unit (3), said cutting unit (4) and said splitting unit (5), wherein said framework (2) is adjusted for being rest on at least approximately horizontal ground surface and is on its first terminal portion (21) furnished with said transporting unit (3), which is arranged at a suitable height above the ground surface and is suitable for successively transporting of single logs (9) in the longitudinal direction of said framework (2), which is defined by longitudinal geometric axis (200), and wherein said framework (2) is on its second terminal portion (22) furnished with said splitting unit (5), while in the central area of said framework (2), namely between the transporting unit (3) and the splitting unit (5), there is a cutting unit (4) attached onto said framework (2), and the cutting unit (4) as such is separately and independently on attachment of said transporting unit (3) and said splitting unit (5) mounted onto the framework (2) of the apparatus (1), and moreover, said hydraulic driving assembly (6) is also mounted onto said framework (2), wherein said framework (2) is optionally furnished with suitable connecting means for establishing a detachable mechanical interconnectionbetween the framework (2) and a tractor or any other vehicle, by means of which the apparatus (1) is transportable to each desired location, and wherein said transporting unit (3) is a hydraulically driven belt conveyor, which is adjusted for transporting of a single log (9) prior to cutting thereof in a direction along said longitudinal geometric axis (200) of the framework (2), namely in a direction towards the cutting unit (4) and the splitting unit (5), and wherein said cutting unit (4) is a motor-driven chain saw, comprising at least a casing (40), a bar (41), which is attached to said casing (40), and an endless cutting chain (42), which is suitably tensioned and guided along the circumference of said bar (41) by means of a chain wheel placed on a driving shaft, which is driven by means of a hydraulic motor, which is powered by said hydraulic driving assembly (6), and wherein said cutting unit (4) is mounted on the framework (2) of the apparatus (1) in such a way that the casing (40) of the cutting unit (4) is located outside of a cross-section of each log (9) to be cut, which is defined by the maximal allowable diameter (D) thereof, wherein said casing (40) is, together with the bar (41), which is attached thereto, and the endless chain (42), which extends along the circumference of said bar (41), pivotal around the geometric axis (400), which extends throughout the pivot point of the casing (40), over the complete cross-section of the log (9), the thickness of which is limited by said maximal diameter (D) and which is intended to be cut and after that also split by means of the apparatus (1), wherein the effective length (L) of the bar (41) is longer than said allowable maximal diameter (D) of the log (9), which is to be cut on said apparatus (1), and moreover, said casing (40) of the cutting unit (4) is, together with the belonging bar (41) and the endless chain (42), attached to the framework (2) of the apparatus pivotally around the horizontal geometric axis (400), which extends parallel to the longitudinal geometric axis (200) of the framework (2) of the apparatus (1), so that by pivotingof said casing (40) around said geometric axis (400), the bar (41) is together with the endless chain (42), which is placed thereon, displaceable from its initial position, namely inactive position, in which it protrudes in approximately vertical direction away from said framework (2), into its terminal position, in which it in a vertical plane passes transversely across the framework (2), so that inbetween of these two positions of the bar (41), the log (9) being intended for cutting and splitting and having a diameter smaller than the maximal allowed diameter (D), can be transported along the longitudinal geometric axis (200) of the framework (2) by means of said transporting unit (3), and wherein said cutting unit (4) further comprises a bar holder (7), to which said bar (41) is reliably attached in a detachable manner and which is furnished with a guide (71’, 71”), which is adjusted to cooperate with a guide (401 ’, 401 ”), which is formed within the casing (40) of the cutting unit (4), so that said bar holder (7) is by means of said guides (71’, 71”; 401’, 401”) displaceable relatively to said casing (40) in a direction along the longitudinal geometric axis (410) of the bar (41), and wherein said cutting unit (4) still further comprises a tensioning means, which is intended for tensioning of the endless chain (42) by means of pushing said bar holder (7) together with the bar (41) attached there-to along said guides (71’, 71”; 401’, 401”) in the longitudinal direction of the bar (41) and away from said casing (40) of the cutting unit (4), and wherein said splitting unit (5) of the apparatus (1) comprises a suitable splitting chute (51), which is adjusted for receiving of a longitudinal log section of a pre-determined length, which is cut-off from the log (9) by means of said cutting unit (4), and, in addition to said chute (51), also a splitting tool (52), a supporting means (53), and a driving means (54) which is powered by means of said driving assembly (6), so that either a splitting tool (52) is by means of said driving means (54) displaceable in a direction towards the interior of said cut-off log section, which is in such casesupported by said supporting means (53), or said supporting means (53) is displaceable by means of said driving means (54) in a direction towards said log section and along the splitting chute (51) together with the log section also towards the splitting tool (52), and wherein said hydraulic driving assembly (6) is suitable for supplying such power to the previously mentioned mechanical units (3, 4, 5) of the apparatus (1), which is required for assuring their functionality, wherein said assembly (6) is either autonomous, or may as such also be energized by a suitable power source, which is available on a tractor or any other vehicle or working apparatus, to which said apparatus (1) is attachable, characterized in that the bar holder (7), to which the bar (41) is attached in the cutting unit (4), in addition to said pair of guides (71 ’, 71”), which extend parallel to each other and are arranged in a plane, which extends transversely with respect to the longitudinal axis (200) of the framework (2) of the apparatus (1), and which are adjusted for sliding along the guides (401 ’, 401”) as formed in the casing (40) of the cutting unit (4) as well as for preventing of any movement of said casing (40) together with the bar (41) in a longitudinal direction along the axis (200) of the framework (2) of the apparatus (1), and in addition to at least two transversal bores (72’, 72”), which are adjusted for receiving of attaching means for establishing of a detachable interconnection between the bar holder (7) and the bar (41), wherein said bores (72’, 72”) extend parallel with each other and transversely throughout the bar holder (7), namely in parallel with the geometric axis (400), around which said casing (40) is pivotal, namely along the geometric axis (200), which extends in the longitudinal direction of the apparatus (1), also comprises a further pair of bores (73’, 73”), which are spaced apart from each other and extend longitudinally, namely in parallel with said guides (71’, 71”; 401’, 401), wherein said bores (73’, 73”) are conceived as hydraulic cylinders,which are, each per se, via suitable hydraulic conduits (730’, 730”) hydraulically interconnected with the hydraulic driving assembly (6), wherein each one of said bores (73’, 73”) is on its side, which is facing towards the bar (41) and towards the framework (2) of the apparatus (1), blinded by a suitable nipple (720’, 720”), and a hydraulic piston (74’, 74”) is inserted into each one of said bores (73’, 73”) such that each hydraulic piston (74’, 74”) protrudes out of the belonging bore (73’, 73”) on its side, which is faced away from the bar (41) and the framework (2) of the apparatus (1), and is moreover adjusted to be rest onto the casing (40) of the cutting unit (4), wherein each piston (74’, 74”) is displaceable along the belonging bore (73’, 73”) either by means of a spring (75’, 75”), which is inserted within the bore (73’, 73”) in the area between the piston (74’, 74”) and the corresponding nipple (720’, 720”), or also by means of hydraulic media, which is supplied towards to the interior of the bore (73’, 73”) through a corresponding hydraulic conduit (730’, 730”), so that each piston (74’, 74”) within the bar holder (7) is by means of the belonging spring (75’, 75”) permanently pressed with a predetermined force towards the casing (40), and when required, said pressing force towards the casing (40) can be still be increased by means of pressurized hydraulic media, which is supplied through said hydraulic conduits (730’, 730”), and in that within the bar holder (7), namely in the area between said longitudinal bores (73’, 73”), and also between said transversal bores (72’, 72”) for receiving of connecting means for establishing of detachable mutual interconnection between the bar (41) and the bar holder (7), a further transversal bore (78) is arranged, which extends transversely to the saw bar (41) plane and in parallel with a geometric axis (400), around which said casing (40) of the cutting unit (4) is pivotal, wherein said transversal bore (78) is via a belonging hydraulic conduit (78’) and together with at least one of the said hydraulic conduits (730’, 730”)hydraulically connectable with the hydraulic driving assembly (6), and wherein a hydraulic piston (79) is inserted within said transversal bore (78), which protrudes out from said bore (78) and is with its outwardly from said transversal bore (78) protruding terminal portion rest on the casing (40) of the cutting unit (4), so that due to the pressure of the hydraulic media towards the piston (79), each guide (71 ’, 71”) on the holder (7) of the bar (41) is pressed towards the complementary guide (401 ’, 401 ”) on the casing (40) of the cutting assembly (4), along which the holder (7) with the bar (41) is displaceable along its longitudinal geometric axis (410) either in a direction towards the casing (40), or in opposite direction.

2. Apparatus according to Claim 1, characterized in that said hydraulic interconnection between the said transversal bore (78), which is acting as a hydraulic cylinder in combination with said piston (79), and said hydraulic driving assembly (6) is arranged in such manner that supplying of pressurized hydraulic media into the transversal bore (78) is enabled only simultaneously with supplying of pressurized hydraulic media via said hydraulic conduits (730’, 730”) to said longitudinal bores (73’, 73”), in which said pistons (74’, 74”), which are rest on the casing (40) of the cutting unit (4), are inserted together with the belonging springs (75’, 75”).

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