The invention belongs to wood processing in the area of performing operations, namely to firewood processing machines, in which cutting blades or wedges are used. Pursuant to the International Patent Classification, such inventions belong to the Class B 27 L 07/06.

In this, the invention is rest on a problem, how to conceive a log processing and firewood splitting machine, which should on the one hand enable efficient cutting of logs to a sequence of longitudinal sections of a predetermined length, and on the other hand splitting of each of such obtained longitudinal sections to several firewood pieces, wherein however the user should also have a possibility of selection among various lengths of the piston stroke in a direction towards the cutting tool and in opposite direction, by which the time period, which is required for performing of each particular stroke, could also be shortened, when this is possible, by which the overall efficiency of the machine could be essentially improved. Log processing machines in various embodiments are known in the state of the art. A relevant machine comprises a sufficiently rigid framework, which is in a stable manner placed onto a ground. A transporting unit is available on said framework, which is suitable for forwarding of a log in a horizontal direction from the intake terminal area of the machine towards the splitting area, in which a splitting tool is fixedly mounted on said framework. A sawing apparatus is mounted on said framework above said transporting unit and is suitable for successively cutting of said timber to longitudinal sections of predetermined length, which is in practice usually 50 cm or less, e.g. 33 cm, which corresponds to the length of a commonly used and commercially interesting firewood piece for household purpose. Moreover, a splitting chute is available on said framework in the area between said sawing apparatus and said splitting tool, and is located at an intermediate level between the level of the ground and the level of said log transporting unit. The volume of said splitting chute is sufficient for receiving of each single longitudinal section of said log, the diameter of which does exceed the maximal allowable diameter, and the length of which does exceed the maximal allowable length. A hydraulic cylinder, which extends in the longitudinal direction of the machine, protrudes into the area of said splitting chute, and a piston rod of a piston, which is inserted within said cylinder, protrudes toward the splitting tool. The piston rod of said hydraulic cylinder piston is intended for pushing each longitudinal log section, when inserted into said splitting chute, in a direction towards the splitting tool. To this aim, the cylinder is fixedly mounted onto said framework, while the piston rod is on its free terminal area furnished with a suitably enlarged resting surface, which is adapted to be rest on said longitudinal log section, when on said longitudinal log section is pushed towards the splitting tool, said hydraulic cylinder is supplied by suitable hydraulic media, and the piston inserted therein is displaceable to and fro in dependency on position of control valves, which are intended for directing the hydraulic media to one or another side of the piston. A reservoir and a pump for compressing said hydraulic media are usually integrated within the area of said framework, and the pump can be driven e.g. by means a Cardan shaft of a tractor, or in any other way. The length of the piston stroke should generally exceed the length of said longitudinal log section. If e.g. in practice the length of the longitudinal log section is 50 cm, then the length of the splitting chute and also the length of the piston stroke should be around 60 cm. ₍

One of the machines characterized by the aforementioned features is disclosed e.g. in EP 9 928 940 Al, while some more sophisticated machines for processing of a log section for the purposes of producing firewood pieces by means of multi-phase splitting are disclosed in SI 25007 A and SI 25612 A. On the other hands, various concepts of splitting tools are known, and one of them is together with mentioning of previously known solution disclosed in SI 24966 A.

Those skilled in the art are aware that essential forces are required for the purpose of splitting, which can generally be produced by means of a hydraulic cylinder and a suitable splitting tool, while on the other hand the strokes of the piston along the cylinder are performed pretty slowly. Each operational cycle on such splitting machines includes a step of sawing of each particular log section, which is followed by forwarding thereof into a splitting chute, upon by switching-on the hydraulic cylinder on the basis of a command, which is triggered by means of a handle or a taste, the operational forward stroke is performed, in which the piston with the piston rod is displaced towards the splitting tool and the piston rod by means of said enlarged resting surface pushes said longitudinal log section in a direction towards the splitting tool, thanks to which the log section is in the area of the splitting tool split to certain number of firewood pieces. As soon as said operational stroke is concluded, namely when the piston reaches the end of its path along the cylinder, the hydraulic media is by means of a control valve redirected to another side of the piston, which leads to gradually returning said piston back to its initial i.e. starting position, in which it is stopped until the next starting command is launched. Said operational cycle therefore includes a relatively slow operational stroke, in which said resting surface on the piston rod is gradually displaced along the complete splitting chute, and also a relatively slow reverse stroke along the complete splitting chute.

It should be noted that said step of sawing of each longitudinal log section may be performed quite independently on splitting as such, and the time required for sawing may be, in particular by processing of thinner logs, essentially shorter than the time, which is required for splitting of each log section.

For the purpose of reducing the time of at least the reverse stroke, WO 2019/093971 Al or EP 3 706 971 Bl proposes application of a hydraulic cylinder, in which the piston is furnished by a throughout passage, in which an one-way valve is integrated, which enables automatically redirecting of the hydraulic media from one side to another side of the piston, and moreover also some accelerated flowing of the hydraulic media in a desired direction. Such measure on the one hand prevents the piston from crashing of s piston to the front wall of the cylinder, and on the other hand also reduces the time, which is required for performing of a complete cycle, since the time period as required for redirecting of the hydraulic media is shortened and the overall efficiency of such machine may herewith be slightly improved. As already mentioned, said operational stroke and the reverse stroke are performed along practically complete length of the splitting chute and regardless to the factual length of each particular log section, which is intended to be split. This means that in the practice the length of each stroke should be approximately 60 cm regardless to that, if e.g. a log section of a maximal allowable diameter and a maximal allowable length of approximately 50 cm is inserted into a splitting chute, or, if an essentially shorter log section having a length e.g. just 33 cm and an essentially smaller diameter would need to be split. In these lastly mentioned circumstances, sawing of the log to longitudinal sections can be performed in an extremely short time period, but upon that, even a shorter log section must be pushed along the complete length of the splitting chute, although at the very beginning of its displacing path, prior to starting of splitting, it is not pressed towards the splitting tool at all. Consequently, in such situations an essential portion of the operational stroke is actually inefficient, and moreover, also the reverse stroke is too long without any reason. It is therefore evident that at least in such situations, in particular by producing of shorter firewood pieces, the overall productivity of such machine could be essentially improved.

The invention refers to a log processing and firewood splitting machine, wherein such machine comprises a rigid and stable framework, which is suitable for being placed on substantially horizontal ground area and in wherein a hydraulic cylinder is embedded substantially in the central area of said framework and is arranged in a horizontal plane at a distance apart from the ground and extends in longitudinal direction of said framework, so that its piston rod is oscillatory to and fro displaceable along its central geometric axis, which extends in a direction towards the central area of the splitting tool, which is firmly mounted on a splitting terminal portion of said framework and at a suitable distance apart from the ground. A splitting chute is also arranged on said framework in the area between said hydraulic cylinder and said splitting tool, and said splitting chute is adapted for receiving of a longitudinal timber section of a predetermined length, which is shorter than a pre-determined maximal length, as well as of a diameter, which is smaller than the pre-determined maximal allowable diameter, wherein the bottom surface of said splitting chute is located below the level of said central geometric axis of the piston rod and said central area of the splitting tool, and said piston rod is displaceable along the complete length of said splitting chute. Said piston rod is on its free terminal portion, which is faced towards the splitting tool, furnished with an enlarged and stable resting surface, which is suitable for pushing of said longitudinal log section towards said splitting tool. A sawing unit is also mounted on said framework at a suitable distance apart from the splitting chute in a direction away from said splitting tool, wherein said sawing unit is suitable for successively cutting of said log to longitudinal sections of a pre-determined length, and moreover, a suitable transporting means is also available on said framework, or adjacent to it, and is suitable for stepwise transporting of said log towards the sawing unit for the purpose of cutting the log to said longitudinal sections of a predetermined length. In this, said hydraulic cylinder is hydraulically integrated into a hydraulic circuit, which in addition to a suitable reservoir and a hydraulic pump, which is suitable for compressing the hydraulic media due to displacing said piston rod to and fro along its central geometric axis, also comprises suitable control valves, which are intended for controlling of each desired cycles of said piston rod and are electrically connected with a control unit in such a way, that each operational stroke of the piston rod is performed on the basis of a signal, which is received from said control unit and is generated therein on the basis of an external command which is forwarded to said control unit, such that during each operational stroke the resting surface on the piston rod is, starting from its initial position adjacent to the first terminal portion of the splitting chute, displaced at a pre-determined distance in a direction towards the splitting tool on the opposite side of the splitting chute, upon which, when the piston rod is stopped after being displaced at said pre-determined distance, supplying of the hydraulic media into said hydraulic cylinder is automatically redirected, so that the reverse stroke of the piston rod in a direction away from the splitting tool and back to its initial position adjacent to the splitting chute is performed automatically.

The invention proposes that, on the one hand, at least two permanent magnets are mounted on said piston road, which are in a direction of said longitudinal geometric axis spaced apart from each other and are located on the same side of the piston rod and substantially in a same diametric plane extending through said longitudinal geometric axis, while on the other hand, an electromagnetic Reed switch is mounted on said framework adjacent to the piston rod, and is adapted to cooperate with each of said permanent magnets for the purpose of generating a suitable electric signal as soon anyone of said magnets reaches the area of sensitivity of said Reed switch. Arrangement of said magnets relative to the Reed switch in the initial position of the piston rod prior to performing the operational stroke or upon conclusion of the reverse stroke is determined in such manner that the distance between the Reed switch and the closest magnet in a direction along said central geometric axis represents the shortest pre-determined length of the operational or reverse stroke of the piston rod, while on the contrary, the distance between the Reed switch and the most distanced magnet in a direction along said central geometric axis represents the longest pre-determined length of the operational or reverse stroke of the piston rod, so that in general the distance between the Reed switch and each of said magnets along said longitudinal geometric axis represents a pre-determined length of the operational or reverse stroke of the piston rod. Said control unit comprises a counter, which is suitable for counting of signals which are received from said Reed switch, and is moreover designed in such a manner that it is, on the basis of a previously entered command, able to redirect the hydraulic media flow towards the cylinder either upon receiving of the first signal from the Reed switch, or upon receiving of the second signal from the Reed switch, but if more than two magnets are available, then said redirecting can also performed upon receiving of any other further pre-determined signal from the Reed switch.

In one of the embodiments of the invention, said piston rod is furnished with a bearing member, which is mounted thereon in the area adjacent to said resting surface and on which said magnets are mounted on the same side of the piston rod and in the same diametric plane extending through said central geometric axis, and moreover also in pre-determined positions relatively to said Reed switch, wherein said bearing member extends substantially along said central geometric axis and parallel to the piston rod in a direction towards the cylinder and at a functionally acceptable distance apart from said Reed switch. In this, said bearing member can be available as a tubular rod, which extends from the area of said resting surface of the piston rod towards the cylinder.

Furthermore, said Reed switch is located within the same vertical plane, in which the resting surface of the piston rod is located in its initial position prior to performing of its operational stroke and upon conclusion of the reverse stroke, wherein the first magnet for determining of a shorter stroke of the piston rod is arranged at a shorter distance apart from said vertical plane of the resting surface on the piston rod in a direction towards the cylinder, while the second magnet is arranged at a longer distance apart from said vertical plane of the resting surface on the piston rod in a direction towards the cylinder. Said control unit can generally be adapted for receiving of a command, by which a pre-determined length of the stroke of the piston rod is selected, namely either a shorter stroke of the piston rod corresponding to the previously mentioned shorter length, or a longer operational or reverse stroke of the piston rod corresponding to the previously mentioned longer length, as well as for receiving of a signal, on the basis of which an operational stroke of a pre-selected length is triggered and executed together with the belonging reverse stroke, which follows automatically.

Another embodiment of the machine is also feasible, in which said control unit is designed in such a manner, that upon inserting of a command for the purpose of performing a shorter stroke of the piston rod corresponding to the previously mentioned shorter length, upon starting of the operational stroke and during the execution thereof, a further signal can be subsequently entered, which however lasts much more time, namely at least two times more than a signal, which is otherwise required for triggering of the piston rod, upon which each subsequent intermediate signal resulting from interaction between the magnet and the Reed switch is ignored unless the most distanced magnet reaches the Reed switch, by which the cylinder is controlled in such a manner that the piston rod performs the longest possible operational and reverse stroke regardless to the initially entered command, by which some shorter stroke has been requested.

The invention will be described in more detail on the basis of an embodiment, which is presented in the attached drawings, wherein

Fig. 1 is a log processing and firewood splitting machine in isometric view;

Fig. 2 is a detail A according to Fig. 1;

Fig. 3 is a machine according to Fig. 1 in top view; Fig. 4 is a schematically shown machine according to Fig. 1, wherein its piston rod is located in its initial position prior to performing of an operational stroke;

Fig. 5 is a schematically shown machine according to Fig. 1, wherein its piston rod is located in its end position after performing of its longest possible operational stroke and prior to performing its reverse stroke back to its initial position according to Fig. 4; and

Fig. 6 is a schematically shown machine according to Fig. 1, wherein its piston rod is located in its end position after performing of a shortened operational stroke and prior to performing its reverse stroke back to its initial position according to Fig. 4.

A log processing and firewood splitting machine, which is shown in Fig. 1, comprises a rigid and stable framework 1, which is suitable for being placed on substantially horizontal ground area. A hydraulic cylinder 2 is mounted on said framework 1 substantially in the central area thereof, and is arranged in a horizontal plane at a distance apart from the ground and extends in longitudinal direction thereof. A piston rod 21 of said cylinder 2 is oscillatory to and fro displaceable along its central geometric axis 200, which extends in a direction towards the central area 31 of the splitting tool 3, which is firmly mounted on a splitting terminal portion 11 of said framework 1 and also at a suitable distance apart from the ground.

A splitting chute 4 is also arranged on said framework 1 in the area between said hydraulic cylinder 2 and said splitting tool 3, and is adapted for receiving of a longitudinal timber section of a predetermined length, which is shorter than a predetermined maximal length, as well as of a diameter, which is smaller than the predetermined maximal allowable diameter. A bottom surface 41 of said splitting chute 4 is located below the level of said central geometric axis 200 of the piston rod 21 and said central area 31 of the splitting tool 3, and the piston rod 21 is displaceable along the complete length of said splitting chute 4.

Moreover, said piston rod 21 is on its free terminal portion 21’, which is faced towards the splitting tool 3, furnished with an enlarged and stable resting surface 22, which is suitable for pushing of said longitudinal log section towards said splitting tool 3.

Still further, a sawing unit 5 is also mounted on said framework 1 at a suitable distance apart from the splitting chute 4 in a direction away from said splitting tool 3, and is suitable for successively cutting of said log to longitudinal sections of a pre-determined length. Moreover, a suitable transporting means is also available on said framework 1 as such, or optionally adjacent to it, and is suitable for stepwise transporting of said log towards the sawing unit 5 for the purpose of cutting the log to longitudinal sections of a pre-determined length.

Said hydraulic cylinder 2 is hydraulically integrated into a hydraulic circuit, which in addition to a suitable reservoir and a hydraulic pump, which is suitable for compressing the hydraulic media due to displacing said piston rod 21 to and fro along its central geometric axis 200, also comprises suitable control valves, which are intended for controlling of each desired cycles of said piston rod 21 and are electrically connected with a control unit 6 in such a way, that each operational stroke of the piston rod 21 is performed on the basis of a signal, which is received from said control unit 6 and is generated therein on the basis of an external command which is forwarded to said control unit 6, such that during said operational stroke the resting surface 22 on the piston rod 21 is, starting from its initial position adjacent to the first terminal portion of the splitting chute 4, displaced at a pre-determined distance L _b L ₂ in a direction towards the splitting tool 3 on the opposite side of the splitting chute 4, upon which, when the piston rod 21 is stopped after being displaced at said pre-determined distance L _b L ₂ , supplying of the hydraulic media into said hydraulic cylinder 2 is automatically redirected, so that the reverse stroke of the piston rod 21 in a direction away from the splitting tool 3, namely back to its initial position adjacent to the splitting chute 4 is performed automatically.

Within the context of resolving the previously mentioned technical problem, on the one hand, at least two permanent magnets 71, 72 are mounted on said piston rod 21, which are in a direction of said longitudinal geometric axis 200 spaced apart from each other and are located on the same side of the piston rod 21 and substantially in a same diametric plane with respect to said longitudinal geometric axis 200, while on the other hand, an electromagnetic Reed switch 8 is mounted on said framework 1 adjacent to the piston rod 21, and is adapted to cooperate with each of said permanent magnets 71, 72 for the purpose of generating a suitable electric signal as soon as anyone of said magnets 71, 72 reaches the area of sensitivity of said Reed switch 8. Combination of said magnets 71, 72 and said Reed switch 8 allows certain deviations in view of mutual distance between the Reed switch 8 and the magnets 71, 72, so that each magnet 71, 72 is efficiently detected by the Reed switch 8 even by splitting log sections of larger diameter, where the cylinder 2 and/or the piston rod 21 may become declines from their ideal position due to extremely increased forces and/or elastic deformations of the framework 1. Arrangement of said magnets 71, 72 relative to the Reed switch 8 in the initial position of the piston rod 21 i.e. prior to performing the operational stroke or upon conclusion of the reverse stroke is determined in such manner that the distance between the Reed switch 8 and the closest magnet 71 in a direction along said central geometric axis 200 represents the shortest pre-determined length Li of the operational or reverse stroke of the piston rod 21, while on the contrary, the distance between the Reed switch 8 and the most distanced magnet 72 in a direction along said central geometric axis 200 represents the longest predetermined length Lj of the operational or reverse stroke of the piston rod 21, so that in general the distance between the Reed switch 8 and each of said magnets 71, 72 along said longitudinal geometric axis 200 represents a pre-determined length of the operational or reverse stroke of the piston rod 21.

In view of previously discussed solutions, which are known in the state of the art, when the maximal length of the log section would be 50 cm, then the length of the splitting chute 4 should be approximately 60 cm, the length L ₂ of the longest stroke of the piston rod 21 would be by means of the magnet 72 limited to 50 cm, while a further magnet 71 positioned at the distance Li at approx. 33 cm could shorten the stroke of the piston rod 21 , whenever shorter log sections need to be split, which leads to essential savings of time as required for performing each cycle.

Said control unit 6 comprises a counter, which is suitable for counting of signals, which are received from said Reed switch 8, and is moreover designed in such a manner that it is, on the basis of a previously entered command, able to redirect the hydraulic media flow towards the cylinder 2 either upon receiving of the first signal from the Reed switch 8, or upon receiving of the second signal from the Reed switch 8, or, if there are more than two magnets 71, 72 available, then said redirecting can also be performed upon receiving of any other pre-determined further signal from the Reed switch 8.

Since the surface of the piston rod 21 should be generally smooth and suitable for sealing during relatively movements of the piston rod 21 relative to the hydraulic cylinder 2, so that from quite technical point of view it appears to be appropriate, if the piston rod 21 is in the area closely to its resting surface furnished with a bearing member 23, on which said magnets 71, 72 are mounted on the same side of the piston rod 21 , in the same plane extending through the longitudinal geometric axis 200, and by taking into consideration also their location in accordance with said pre-determined lengths L L ₂ of strokes of the piston rod 21, wherein said bearing member 23 extends substantially along said central geometric axis 200 and parallel to the piston rod 21 in a direction towards the cylinder 2 and at a functionally acceptable distance apart from said Reed switch 8. The expression functionally acceptable distance between the bearing member 23 with magnets 71, 72 and the Reed switch 8 should be understood that the distance still falls within the area, in which said Reed switch 8 is capable to detect, at a sufficient reliability, each disposable magnet 71, 72, which is located in its adjacency. In the shown embodiment (Figs. 4 - 6) said bearing member 23 is a tubular rod, which extends from the area of said resting surface 22 of the piston rod 21 towards the cylinder 2. Besides, in this shown embodiment said Reed switch 8 is located within the same vertical plane, in which the resting surface 22 of the piston rod 21 is located in its initial position prior to performing of its operational stroke and upon conclusion of the reverse stroke, wherein the first magnet 71 for determining of a shorter stroke of the piston rod 21 is arranged at a shorter distance L] apart from said vertical plane of the resting surface 22 on the piston rod 21 in a direction towards the cylinder 2, while the second magnet 72 is arranged at a longer distance L ₂ apart from said vertical plane of the resting surface 22 on the piston rod 21 in a direction towards the cylinder 2.

Said control unit 6 is adapted for receiving of a command, by which a predetermined length of the stroke of the piston rod 21 is selected, namely either a shorter stroke of the piston rod 21 corresponding to the shorter length L _b or a longer operational or reverse stroke of the piston rod 21 corresponding to the longer length L2, and moreover also for receiving of a signal, on the basis of which an operational stroke of a pre-selected length L,, L ₂ is then triggered and executed together with the belonging reverse stroke, which however follows automatically. Said control unit 6 can be furnished with a display, on which each selected length of the stroke of the piston rod 21 can be seen, i.e. a splitting mode in the context of the selected length of the stroke of the piston rod 21. On the other hand, said control unit 6 is also furnished by a suitable input panel, via which on the one hand commands related to the length of the selected stroke of the piston rod 21 can be entered, and on the other hand also the signals for performing of each selected operational cycles can be inserted. As soon as a longitudinal log section of a predetermined length is inserted into a splitting chute 4, then the user is able to initiate the operational stroke of the piston rod 31 either by means of a handle or a control stick (joystick), and said operational stroke is then automatically followed by a reverse stroke, in which the piston rod 21 is returned back to its initial position.

Said control unit 6 can also be upgraded by an additional function, that upon inserting of a command for the purpose of performing a shorter stroke of the piston rod 21 corresponding to the shorter length L upon starting of the operational stroke and during the execution thereof, a further signal can be entered, which however lasts much more time, namely at least two times more, than a signal, which is otherwise required for triggering the piston rod 21, upon which each subsequent intermediate signal resulting from interaction between the magnet 71 and the Reed switch (8) is ignored unless the most distanced magnet 72 reaches the Reed switch 8, by which the cylinder 2 is controlled in such a manner that the piston rod 21 performs the longest possible operational and reverse stroke regardless to the initial command, by which some shorter stroke thereof has been requested. In the practice this would mean that the user, despite to previously selecting a shortened stroke of the piston rod 21, is during the operational stroke still able to change this decision by means of some longer activation of the control stick and prolongation of the signal achieves prolongation of the operational stroke up to the maximal allowable length.

The overall concept however enables to the user shortening of the stroke of the piston rod 21, in order to shorten the operational cycle, whenever possible, which during a long-term exploitation of the machine may lead to essential increasing of efficiency and productivity.