Firewood splitting apparatus with improved tensioning of endless saw chain in a log cutting unit thereof

Abstract

The invention refers to a firewood splitting apparatus (1) with improved tensioning of endless chain (42) in a log cutting unit (4), which moreover excels in simplified and safe replacing of a worn or damaged chain (42). Tensioning of said chain (42) is established by displaceability of a bar holder (7) together with a bar (41) relatively to a casing (40) of a cutting unit (4), which is achieved by means of a combination of springs (75', 75'') and hydraulic pistons (74', 74'') which are placed in bores (73', 73'') within said bar holder (7). The bar holder (7) is rest on the casing (40) in the area of said pistons (74', 74'') and is pressed away from the casing (40). Moreover, the bar holder (7) is furnished with a retaining means (77), which is adjusted to cooperate with an arresting mechanism (45), which is mounted on said casing (40) of the cutting unit (4), and for retaining of the bar holder (7) in a pre-determined position, in which each one of said pistons (74', 74'') is, in the absence of the pressure of the hydraulic media, against the pressure of said springs (75', 75'') pushed towards the interior of each belonging bore (73', 73'').

Description

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

[0002] The invention relates to a firewood splitting apparatus with improved tensioning of endless saw chain in a log cutting unit thereof, wherein such apparatus, among other comprises a log cutting unit, which is suitable for successively cutting a log to longitudinal sections of a pre-determined length, which are upon that each per se 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 purpose of the invention is to improve said cutting unit on such firewood splitting apparatus, so that, in addition to usual tensioning of an endless saw chain, which extends along the circumference of a corresponding saw bar, on the one hand, said tensioning of the saw chain could be intensified, when cutting of logs is performed in extreme conditions at the highest speed of said endless saw chain by simultaneously pivoting the casing together with said bar and the saw chain placed thereon at the highest angular velocity around its pivot point, and on the other hand, in the need of replacement of a worn or damaged saw chain, said tensioning shall be temporarily totally eliminated, and the bar shall be retained in a position, in which the saw chain is completely loose and can be easily removed from the cutting unit and replaced with another one without exposing the user to any risk of being injured. 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, which is disclosed in DE 101 07 762 Al, 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 bar. As known, during operation of the cutting unit the saw chain exposed to extreme tensioning stresses, friction and thermal influences, which consequently leads to wearing, so that in the practice, the saw chain may quickly extend and becomes pretty loose. In order to assure smoothly guiding of the saw chain along the circumference of the bar, and also throughout the wood, which is to be cut, the saw chain must be optimally tensioned all the time. As soon as the saw chain is extended and becomes loose, it must be re-tensioned, since on the contrary the saw chain could exit the guide on the bar, or the engagement between the saw chain and teeth on the driving chain wheel could be dismissed, which might consequently lead to interruption of cutting, or even worse, to serious mechanical damages of the saw chain or other components of the cutting unit. Moreover, none of said documents also does not provide any useful information about guiding of the bar, when it is pivoted around said geometric axis. Namely, the structure of the wood is never uniform, which in combination with wearing of the saw chain normally leads to generation of additional forces, which may, in addition to said tension stressed within the saw chain during cutting, act in different directions, which may lead to deflection of the bar from its ideal position within the plane, which extends transversely with respect to the longitudinal direction of the splitting apparatus, so that the front surfaces of each produced longitudinal log section are not flat. Such deflection of the bar along the cutting process and during each pivoting thereof may lead to extreme loadings in the area of said bearing means of the cutting unit, which during the time leads to decreasing of reliability of guiding of the saw unit, which involves further troubles and making situation even worse and worse. 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.

[0007] 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.

[0008] 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.

[0009] 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. 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 can 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.

[0010] 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 always desired 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.

[0011] The proposed invention refers to a firewood splitting apparatus with improved tensioning of an endless chain in a log cutting unit. Said apparatus 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 predetermined length, a splitting unit, which is adjusted for splitting of each cut-off 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.

[0012] In this, 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.

[0013] Furthermore, said transporting unit is conceiver 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.

[0014] 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.

[0015] 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, wherein 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 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.

[0016] 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.

[0017] 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.

[0018] In accordance with the present 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. 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. In addition, the bar holder further comprises a suitable retaining means, which is adjusted to cooperate with an arresting mechanism, which is mounted on the casing of the cutting unit for the purpose of retaining the bar holder in a pre- determined position, in which each piston, when released of the pressure of the hydraulic media, is pushed towards to the interior of the corresponding bore against the force of the belonging spring.

[0019] In a preferred embodiment of the invention, each one of said springs is a helical compression spring, and each one of said nipples is a threaded nipple, by means of which also pre-tensioning of the belonging spring is adjustable.

[0020] In a further embodiment of the invention, said retaining means is conceived as a cylindrical protrusion, which is arranged on the external surface of the bar holder and is perpendicular with respect to said external surface, while the arresting mechanism, which is adjusted for cooperation with the retaining means, is available on the casing of the cutting unit and comprises an arresting plate, which is furnished with arresting cutouts, which are in a direction along the longitudinal geometric axis of the bar spaced apart from each other, and are moreover located at different levels, namely at different distances apart from said the longitudinal geometric axis of the bar, so that the cutout, which is more distanced apart from the geometric axis in the pivot point of the casing, is more distanced apart from said longitudinal geometric axis of the bar than the other cutout, which is arranged closer to the geometric axis in the pivot point of the casing. Each of said cutouts is adjusted for resting and supporting of said retaining means exclusively in the direction towards the bar, but not also in opposite direction, namely not also in a direction towards said geometric axis in the pivot point of the casing as such. Said arresting plate is guided in guides and is at a pre-determined distance displaceable in a direction transversely with respect to the longitudinal geometric axis of the bar and is moreover by means of a spring pressed towards said retaining means, which is fixed on the external surface of the bar holder, wherein said spring is a helical compression spring, which is mounted in the area between the cantilevered portion of the arresting plate and a cantilevered portion on the casing, and is guided and secured in its functional position by means of a bolt, which is inserted through it and extends through said cantilevered portions on the arresting plate and on the casing of the cutting unit.

[0021] Embodiments of the invention will be explained in more detail on the basis of the attached drawings, wherein

[0022] Fig. 1 a schematically presented firewood splitting apparatus with improved tensioning of an endless chain in a log cutting unit thereof, in isometric view;

[0023] Fig. 2 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;

[0024] Fig. 3 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;

[0025] Fig. 4 a chain bar holder in the apparatus according to Fig. 1, presented in a crosssection along its central longitudinal plane, extending parallel to the dominant surface of the bar as such; Fig. 5 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;

[0026] Fig. 6 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:

[0027] Fig. 7 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.

[0028] A firewood splitting apparatus 1 with improved tensioning of an endless chain 42 in a log cutting unit 4 thereof is schematically and quite in generally presented in Fig. 1. Such apparatus 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. 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 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 is on its second terminal portion 22 furnished with said splitting unit 5. In addition to that, 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. 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.

[0029] Said transporting unit 3 is generally 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.

[0030] Said cutting unit 4 is generally 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. 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 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 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. 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. As mentioned, 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.

[0031] Said cutting unit 4 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. Consequently, 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. 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 of the bar 41 and away from said casing 40 of the cutting unit 4. Namely, said endless chain 42 on the one hand extends along the circumference of the bar 41, which is displaceable to and fro along said guides 71 ’, 71 ”;401 ’, 401” in the radial direction relatively to said geometric axis 400 in the pivot point of the casing 40 of the cutting unit 4, but on the other hand also over a driving chain wheel, which is embedded within the casing 40 in a fixed position in the area between the bar holder 7 and said geometric axis 400 in the pivot point of the casing 40. Consequently, by displacing the bar holder 7, together with the bar 41 attached thereon, in a direction away from said geometric axis 400 in the pivot point of the casing 4, the chain 42 is tensioned, or vice versa, by displacing the bar holder 7 together with the bar 41 in opposite direction, the chain 42 is released.

[0032] 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.

[0033] 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.

[0034] 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.

[0035] Within the context of the initially exposed technical problem, the invention is however focused to tensioning of said endless cutting chain 44 in said cutting unit 4 by simultaneously providing a simplified and safe approach by replacement of the chain, when the last is either damaged or its functionality is hindered due to e.g. wearing or loss of sharpness in the area of cutting edges thereof. To this aim, the invention provides that the bar holder 7, to which the bar 41 is attached in the cutting unit 4, is furnished with a pair 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 to slide along the guides 401’, 401 ” formed in the casing 40 of the cutting unit 4 and also 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. Moreover, said bar holder 7 is furnished with at least two, in the shown embodiment just two, transversal bores 72’, 72” (Fig. 4), which are adjusted for receiving of attaching means, preferably screws, 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 the casing 40 is pivotal, in fact along the axis 200 in the longitudinal direction of the apparatus 1. Whenever the bar holder 7 together with the bar 41 attached thereto is displaced along said guides 71’, 71 ”; 401’, 401” in a direction away from the pivoting axis 400 of the casing 40, the chain 42 is tensioned, while by displacing the bar holder 7 in opposite direction the chain 42 is released. On the other hand, said bar holder 7 is moreover furnished with 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 substantially functioning 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 bar 41 i.e. 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 piston 74’, 74” protrudes outwardly from the belonging bore 73’, 73” on its side, which is faced away from the bar 41 i.e. the framework 2 of the apparatus 1 , and is moreover adjusted to be rest onto the casing 40 of the cutting unit 4. 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”. 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 force towards the casing 40 may be still be increased due to pressurized hydraulic media, which is supplied through said hydraulic conduits 730’, 730”. By pushing the bar holder 7 in a direction away from the casing 40 by means of said pistons 74’, 74” forced exclusively by means of said springs 75 ’,75”, such pre-tensioning of the saw chain 42 is assured that the saw chain 42 is regularly running over the driving chain wheel and along the circumference of the bar 41. However, due to additional tensioning force, which is generated by each one of said pistons 74’, 74” due to the pressurized hydraulic media acting there-to, a supplemental tensioning of the saw chain 42 is established during operation thereof. Intensity of such supplemental tensioning depends on the pressure of the hydraulic media, which may in the shown embodiment be adjusted to approximately 30 bar. Positioning of the bar holder 7 in the context of tensioning or releasing of the saw chain 42, or also retaining of the bar holder 7 in a pre-determined position, regardless to said permanently acting forces of springs 75’, 75” within said bores 73’, 73” in the bar holder 7, is according to the invention achieved in such manner, that the bar holder 7 is furnished with a retaining means 77, which is adjusted to cooperate with an arresting mechanism 45, which is mounted on the casing 40 of the cutting unit 4 for the purpose of retaining the bar holder 7 in a pre-determined position, in which each piston 74’, 74”, when released of the pressure of the hydraulic media, is pushed towards to the interior of the corresponding bore 73’, 73” against the force of the belonging spring 75’, 75”.

[0036] In a preferred embodiment, each of said springs 75’, 75” is a helical compression spring, and each nipple 720’, 720” is a threaded nipple, by means of which also pre-tensioning of the belonging spring 75’, 75” may be adjusted, when required.

[0037] As evident in Figs 2 and 3 as well as 5 - 7, said retaining means 77 is conceived as a cylindrical protrusion, which is arranged on the external surface 70 of the bar holder 7 and is perpendicular with respect to said surface 70, while the arresting mechanism 45, which is adjusted for cooperation with retaining means 77, is available on the casing 40 of the cutting unit 4 and comprises an arresting plate 451, which is furnished with arresting cutouts 4511, 4512, which are in a direction along the longitudinal geometric axis 410 of the bar 41 spaced apart from each other, and are moreover located at different levels i.e. at different distances apart from said the longitudinal geometric axis 410 of the bar 41, so that the cutout 4511, which is more distanced apart from the geometric axis 400 in the pivot point of the casing 40, is more distanced apart from said longitudinal geometric axis 410 of the bar 4 than the other cutout 4512, which is arranged closer to the geometric axis 400 in the pivot point of the casing 40, Each of said cutouts 4511, 4512 is adjusted for resting and supporting of said retaining means 77 exclusively in the direction towards the bar 41, but not also in opposite direction i.e. in a direction towards said geometric axis 400 in the pivot point of the casing 40 as such. Said arresting plate 451 is guided in guides 4521, 4522 and is at a pre-determined distance displaceable in a direction transversely with respect to the longitudinal geometric axis 410 of the bar 41, and is moreover by means of a spring 453 pressed towards said retaining means 77, which is fixed on the external surface of the bar holder 7.

[0038] In the shown embodiment, said spring 453 is a helical compression spring, which is mounted in the area between the cantilevered portion 4510 of the arresting plate 451 and a cantilevered portion 454 on the casing 40, and is properly guided and secured in its functional position by means of a bolt 455, which is inserted through it and extends through said cantilevered portions 4510, 454 on the arresting plate 451 and on the casing 40.

[0039] As soon as rotation of the driving chain wheel for driving of the saw chain 42 along the circumference of the bar 41 is terminated, and as soon as the pressure of the hydraulic media within the bores 73’, 73” is released, then the bar holder 7 is by means of springs 75’, 75” pressed in a direction away from the casing 40. In such a state, the user has the opportunity to remove and replace the saw chain 42, which is performed in such a way, that the bar 41 , together with the bar holder 7, needs to be pressed against the force of said springs 75’, 75” in a direction towards the casing 40 i.e. towards the geometric axis 400 in the pivot point of the casing 40 in such extent, that by displacing of the bar holder 7 along the guides 401’, 401 ” of the casing 40, the arresting plate 451 of the arresting mechanism 45 in the area of its cutout 4512, which is arranged closer to the geometric axis 400, is due to the pressure of the spring 453 becomes arrested by the retaining means 77 on the casing 40 of the cutting unit 4. Upon that, due to said arresting, the bar holder is prevented from being displaced in a direction away from said geometric axis 400 in the pivot point of the casing 400, despite to force of the springs 75 ’,75”, to which it is still exposed. In such position of the bar holder 7 and the bar 41, the saw chain 42 is completely released and can be easily removed and replaced with another one. As soon as the saw chain 42 is placed along the circumference of the bar 41 and over the driving chain wheel, then by simply displacing the arresting plate 451 against the force of the spring 453 said temporarily positive interlocking between the arresting plate 451 and the arresting cutout 4512 is released, upon which the bar holder 7 is by means of springs 75’, 75” therein displaced in a direction away from said geometric axis 400 in the pivot point of the casing 4, so that the bar holder 41 together with the bar 41 assures a required pre-tensioning of the saw chain 42 by means of the force generated by said springs 75 ’,75”.

Claims

CLAIMS1. Firewood splitting apparatus (1) with improved tensioning of endless chain (42) in a log cutting unit (4), said apparatus 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 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 predetermined 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 (73 O’, 730”), and in that the bar holder (7) further comprises a retaining means (77), which is adjusted to cooperate with an arresting mechanism (45), which is mounted on the casing (40) of the cutting unit (4) for the purpose of retaining the bar holder (7) in a predetermined position, in which each piston (74’, 74”), when released of the pressure of the hydraulic media, is pushed towards to the interior of the corresponding bore (73’, 73”) against the force of the belonging spring (75’, 75”).

2. Firewood splitting apparatus (1) with improved tensioning of endless chain (42) in a log cutting unit (4) according to Claim 1 , characterized in that each one of said springs (75’, 75”) is a helical compression spring, and each one of said nipples (720’, 720”) is a threaded nipple, by means of which also pre-tensioning of the belonging spring (75’, 75”) is adjustable.

3. Firewood splitting apparatus (1) with improved tensioning of endless chain (42) in a log cutting unit (4) according to Claim 1 or 2, characterized in that said retaining means (77) is conceived as a cylindrical protrusion, which is arranged on the external surface (70) of the bar holder (7) and is perpendicular with respect to said external surface (70), while the arresting mechanism (45), which is adjusted for cooperation with the retaining means (77), is available on the casing (40) of the cutting unit (4) and comprises an arresting plate (451), which is furnished with arresting cutouts (4511, 4512), which are in a direction along the longitudinal geometric axis (410) of the bar (41) spaced apart from each other, and are moreover located at different levels, namely at different distances apart from said the longitudinal geometric axis (410) of the bar (41), so that the cutout (4511), which is more distanced apart from the geometric axis (400) in the pivot point of the casing (40), is more distanced apart from said longitudinal geometric axis (410) of the bar (4) than the other cutout (4512), which is arranged closer to the geometric axis (400) in the pivot point of the casing (40), wherein each of said cutouts (4511, 4512) is adjusted for resting and supporting of said retaining means (77) exclusively in the direction towards the bar (41), but not also in opposite direction, namely not also in a direction towards said geometric axis (400) in the pivot point of the casing (40) as such, and wherein said arresting plate (451) is guided in guides (4521, 4522) and is at a pre-determined distance displaceable in a direction transversely with respect to the longitudinal geometric axis (410) of thebar (41) and is moreover by means of a spring (453) pressed towards said retaining means (77), which is fixed on the external surface of the bar holder (7).

4. Firewood splitting apparatus (1) with improved tensioning of endless chain (42) in a log cutting unit (4) according to Claim 3, characterized in that said spring (453) is a helical compression spring, which is mounted in the area between the cantilevered portion (4510) of the arresting plate (451) and a cantilevered portion (454) on the casing (40), and is guided and secured in its functional position by means of a bolt (455), which is inserted through it and extends through said cantilevered portions (4510, 454) on the arresting plate (451) and on the casing (40).

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