WO2005072924A1

WO2005072924A1 - Cutting and splitting device

Info

Publication number: WO2005072924A1
Application number: PCT/FI2005/000047
Authority: WO
Inventors: Tarmo Pitkäniemi
Original assignee: Agromaster Oy
Priority date: 2004-01-22
Filing date: 2005-01-21
Publication date: 2005-08-11
Also published as: FI20040095A0

Abstract

A cutting and splitting device for cutting and splitting tree trunks, the cutting and splitting device including a cutting tool for cutting the trunk and a splitting tool having a splitting piston (1), a splitting blade (2), and a power unit (3) for moving the splitting piston and for pushing the cut piece of wood through the cut-off blade using the splitting piston. According to the invention, the cutting tool includes a straight cut-off blade (4) attached to the splitting piston (1), which cut-off blade is in parallel to the path of motion of the splitting piston; as well as a fixed trunk support (6) for supporting the trunk (7) in the transverse direction with respect to the path of motion of the splitting piston as the cut-off blades cuts off the trunk.

Description

CUTTING AND SPLITTING DEVICE

FIELD OF THE INVENTION The invention relates to a cutting and splitting device as defined in the preamble of claim 1.

BACKGROUND OF THE INVENTION At present, several different cutting and splitting devices are used that both cut and split the tree trunk. The cutting and splitting devices that saw the tree trunk in two usually have a separate splitting piston that pushes the cut wood through the splitting blade. In this manner, the devices have both a motor rotating either a chain saw or a circular saw and a hydraulic cylinder using a splitting piston. These require their own guide means in order to work together in the desired manner. Another basic structure of known cutting and splitting devices is the cut-off blades. The blades can be cylindrical or guillotine-like and they have a spike or a form that in conjunction with the cutting splits the wood. The devices are very fast and efficient and -thus also big and expensive. In addition, they work unsatisfactorily; the chopped wood does not come unstuck, but the wood usually only splits at the one end . The problem with all known cutting and splitting devices is their complicated and expensive structures. A cutting and splitting device that costs 4000- 8000 euros is too expensive with respect to the bene- fit to be gained in individual holiday villas, detached houses and even in farms. Due to this, present cutting and splitting devices are mainly only used by those who besides their own consumption also sell firewood. Known from patent publications FI 76725, US

5,492,159 and US 4,573,507 are cutting and splitting devices that are designed for both cutting the firewood and splitting it to be used as fine chopped firewood. All these devices are based on a straight blade that is pressed through the tree trunk and on another blade that substantially simultaneously with the cutting splits the wood. The problem with all these is the very big momentary power requirement when the wood is pressed with a transverse blade to cut it while at the same time splitting it. Due to this, the devices are big, slow, heavy and expensive. Due to the huge powers, the devices also are susceptible to damage. In addition, a transverse cutting based on force leaves a weak cutting mark. Especially certain wood species, having dried a little and cut to be relatively short, are smashed into small sticks, so these devices are not suitable for commercial production of firewood. As such, the good sales of small splitting devices in hardware stores has shown that people using firewood have the desire and need to facilitate and simplify the acquisition of firewood. These kind of small splitting devices that just split the wood, meaning that the wood has to be first sawn into sections, have, however, shown to be very hazardous.

OBJECTIVE OF THE INVENTION The objective of the invention is to eliminate the disadvantages referred to above. One specific objective of the invention is to disclose a new type of cutting and splitting device that both cuts and splits the tree trunk very efficiently and fast, but, however, with such a small momentary power requirement that the device can be made very simple, safe and reliable in terms of its structure and operation compared to prior-art devices. Further, the objective of the invention is to disclose a new type of cutting and splitting device that is so inexpensive in terms of its purchasing costs that its use also in the preparation of firewood for individual small-sized flats is economically profitable .

SUMMARY OF THE INVENTION The cutting and splitting device in accordance with the invention is characterised by what has been presented in claim 1. The cutting and splitting device in accor- dance with the invention is designated for cutting and splitting of tree trunks, in other words, for making fine chopped firewood from pruned tree trunks. The cutting and splitting device includes a cutting tool for cutting the tree trunk, and a splitting tool hav- ing a splitting piston, a splitting blade and a power unit for moving the splitting piston and for using the splitting piston to push the piece of wood already cut through the splitting blades. According to the invention, the cutting tool includes a straight, slitting cut-off blade that has been connected to the splitting piston and that moves together with it, the cutting and slitting blade edge of which cut-off blade is at an oblique angle with respect to the path of motion of the splitting piston and which is in parallel to the path of motion of the splitting piston; as well as a fixed trunk support for supporting the tree trunk with respect to the path of motion of the splitting piston in the transverse direction as the cut-off blade cuts the tree trunk. ,In this manner in the invention, the splitting piston and the cut-off blade together form a mobile complex, whereby as the cut-off blade cuts a piece off the tree trunk, the splitting piston pushes the piece that was cut through the splitting blades. During the backward motion, the piece of wood cut by the cut-off blade then moves in between the splitting piston and the splitting blade to wait for the next pushing movement of the splitting piston. In this man- ner in the invention, the cutting and splitting of the same piece is not performed simultaneously, instead in two consecutive phases. This complex that moves together can be a rigid structure, i.e. the splitting piston and the cut-off blade form a fixed complex. Another possibility is that they are just connected to one another so that as the one is moved, the other one moves as well. The obliqueness of the slitting blade being used in the cutting and splitting device can be relatively long, i.e. almost the same in length as the motion of path of the splitting piston. In this manner, the momentary force needed in the cutting is minimised, and together with the simultaneous splitting, the cutting is made a smooth operation that is the same in length as the path of motion of the splitting piston. Although it is worth utilising the entire path of motion of the splitting piston to minimise the force, it is, however, possible that the slitting blade is a little shorter, e.g. about a half of the path of motion in question. A long slitting blade can be used to minimise the transverse forces affecting the splitting piston. To completely eliminate these transverse forces, it is possible to use in the invention a V shaped blade, i.e. two opposite blades that are at an angle with respect to one another. In this manner, the blades together and simultaneously slit the tree trunk from opposite sides as the tree trunk finally cuts at the bottom of the V shape. With this structure, the transverse slitting forces cancel one another. Preferably, the cut-off blade extends vertically upward from the upper surface of the splitting piston, i.e. the cutting of the tree trunk is per- formed upper than the slitting of the piece of tree trunk. In this manner, the piece of tree trunk that was cut can be made , to gravitationally move from the cutting step to the slitting tool just by suitably guiding. It is, however, possible that e.g. the backward motion of the slitting piston is utilised, using a suitable lever, to find a function that turns and guides the piece of tree trunk accurately into the desired place in between the slitting piston and the slitting blade. It is also possible that the cut-off blade extends obliquely upward or even nearly in the hori- zontal direction from the splitting piston, whereby the feeding of the tree trunks is performed obliquely downward or nearly in the vertical direction. This can be very advantageous when there is a wish to automate the feeding of the tree trunks, because the feeding of the tree trunks can be performed gravitationally e.g. along a suitable trough with no mechanical mobile parts . Preferably, the trunk support includes supporting surfaces on both sides of the mobile cut-off blade so that the cut-off blade extends from the supporting surfaces as the tree trunk is being cut. In other; words, on both sides of the path of motion of the cut-off blade there are separate supporting surfaces , on both of which the tree trunk is supported when cutting. In this manner, the tree trunk is not subjected to any kinds of torque moments by the cutoff blade, so it is safe for the machine operator to hold on to the one end of the tree trunk and to push the tree trunk into the device. Naturally, it is also possible that the cutting and splitting device is provide with an automatic feeding of tree trunks, meaning that there is no need to touch the tree trunk during its cutting or thereafter. The trunk support of the cutting tool is characterised by the fact that it keeps the trunk immovable when the slitting blade hits the trunk, cutting it. Thus, the trunk support must have supporting surfaces that prevent the movement of the trunk in the direction of the slitting movement of the blade, i.e. both in the direction of motion of the splitting piston and upward. In this manner, the trunk support can be a suitably directed angle support . The trunk support can also be formed by an aperture with its edges that defines the maximum diameter of the trunk being cut. In this manner, the aperture supports the trunk in every direction in the transverse plane of the trunk, and furthermore the size of the aperture guarantees that one does not feed into the device trunks that are bigger than for what the device has been dimensioned. Preferably, the cutting and splitting device includes an adjustable limiter, known per se from cutting and splitting devices, for determining the cut length of the trunk. Preferably, the cutting and splitting device includes a switch for controlling the starting of the simultaneous splitting and cutting movement. The switch can be disposed e.g. in conjunction with the limiter so that the switch functions as the end of the trunk meets the limiter. The switch can also be disposed in conjunction with the trunk support. Simi- larly, it is also possible that the cutting and splitting device includes a separate switch lever or the like which is operated by the machine operator by hand, foot or some other suitable part of the body. Naturally, the device can also be operated in a wire- less manner known per se between the cutting and splitting device and the machine operator. In the foregoing, the invention has been described by means of a structure whose blade is mobile and the trunk support fixed. Naturally, the device in accordance with the invention can also be implemented vice versa, i.e. with a fixed blade and a mobile trunk support. In order to make the claims of the invention clear and legible, this embodiment is incorporated herein as separate independent claim 11. However, various structural alternatives can vary even in this embodiment, as has been described in conjunction with the embodiment as defined in claim 1. The cutting and splitting device can also be implemented so that one uses two separate hydraulic cylinders, whereby the one uses a slitting cut-off blade and the other a splitting cylinder that pushes the cut wood through the splitting blade. In that case it is even possible that the paths of motion of the hydraulic cylinders are perpendicular to one another. In this manner, the trunk can be fed into the machine in the splitting direction of the piece resulting from the cutting so that the piece does not need to be turned before splitting. The cutting and splitting device in accordance with the invention has several advantages compared to prior art. The cutting and splitting device has a very simple structure, with just one power unit and one back and forth movement that implements two separate functions. The cutting and splitting device is easy and safe to use. Due to the simplicity of the structure, the device is reliable and easy to maintain and repair. The power requirement is insignificant compared to the prior-art devices, and the cutting mark is excellent compared to other cutting devices. Due to the facts presented above, the manufacturing costs of the device are only half of the manufacturing costs of the present cutting and splitting devices that have the same functions.

LIST OF FIGURES In the following section, the invention will be described in detail by means of examples with reference to the attached drawing, in which Fig. 1 is a schematic representation illustrating one cutting and splitting device in accordance with the invention; and Fig. 2 is a schematic representation illus- trating another cutting and splitting device in accordance with the invention.

DETAILED DESCRIPTION OF THE INVENTION The cutting and splitting device as shown in Fig. 1 includes a splitting piston 1 that is quadratic in cross section, which can be moved back and forth in an upward open V shaped support trough 12 using a power unit 3, i.e. a hydraulic cylinder. Arranged at the one end of the support trough 12 is a splitting blade 2, a cross blade whose altitude can be changed according to the thickness of the wood being split so that the wood can be split either into two or four sections . Attached, welded or bolted to one long edge of the elongated splitting piston 1, which edge is pointed upward, is a sheet-like cut-off blade 4, extending directly upward from the splitting piston. The cut-off blade 4 is in parallel to the path of motion of the splitting piston, and the upper edge of the sheet forms a sharp, cutting edge 5, which is straight and descending towards the front end of the splitting piston, i.e. toward the splitting blade 2. Attached to the device body (not shown in the figure) in the section of the path of motion of the cut-off blade 4 is a trunk support 6. It is formed by two rigid vertical supports that are disposed at a distance from one another so that a slot is formed between them, in which the blade 4 can freely move. Disposed at the upper ends of both vertical supports are horizontal parts that extend towards the blade 4 so that the trunk supports form supporting surfaces 8 of 90 degrees that are oriented towards the cutting edge 5 of the blade. Furthermore, the cutting and splitting device includes an adjustable limiter 9 for adjusting the distance between the limiter and the blade 4, i.e. for adjusting the length of the piece of trunk to be cut; guide means 10 for guiding the cut piece to the splitting piston in the desired position in a controlled manner; as well as in conjunction with the limiter, a switch 11 for starting up the cutting and splitting device. Similarly, the device includes a hydraulic pump 13, an oil reservoir 14, a 4 -path valve 15, and a control circuit 16. The cutting and splitting device as schemati- cally shown in Fig. 1 functions as follows. The pump 13 can be started up by the control circuit 16, and can operate continuously also between the working paces. In that case, the 4-path valve 15 directs the flow of oil directly from the pump 13 back into the reservoir 14. As the trunk being treated 7 is pushed into the device in between the blade 4 and the guiding surfaces 8 of the trunk support 6 so that the end thereof collides with the limiter 9 and with the switch at the same time, the following happens. The control circuit 16 turns the valve 15, directing the flow of oil to the external end of the piston 3. In that case, the splitting piston moves towards the splitting blade 2, and the piece of wood that is disposed in the supporting trough between them pushes its way through the splitting blade, splitting into two or four sections. During the same pushing movement, the cut-off blade 4 at first pushes the trunk 7 towards the supporting surfaces 8, and thereafter the blade cuts off the trunk. As the piece of trunk falls down- ward, the switch is released, and the control circuit 16 turns the valve 15, whereby the hydraulic cylinder 3 forces the splitting piston 1 and the cut-off blade into the initial position. As the splitting piston 1 reverts back into the initial position, the cut piece of wood can fall into the supporting trough 12. As the splitting piston 1 reverts back into the initial posi- tion, the valve 15 turns the flow of oil again directly into the oil reservoir to wait for the next working period. In this manner, with each working period, the device cuts a piece off the trunk, while at the same time splitting the piece that was cut during the previous working period. Naturally it is possible that the control of the device has been so arranged that it is given just one control impulse, e.g. using the switch 11, and thereafter the control circuit 16 controls the valve 15 during the entire working period from the idle phase via the working phase and return phase to the idle phase to wait for the next control impulse. Fig. 2 illustrates another embodiment of the invention, in which the same numerals refer to the same parts as in the embodiment of Fig. 1. In contrast to the embodiment shown in Fig. 1, there is a trunk support 17, formed by two adjacent sheets having round holes. The trunk is pushed through the holes, and the blade that moves between the sheets cuts off the trunk as it is supported on the edges of the holes. At the same time, the diameter of the holes determines the maximum diameter of the trunks being treated. Another difference compared to the embodiment as shown in Fig. 1 is the coupling of the blade 4 and the splitting piston 1 to one another. The blade 4 is attached at its lower edge to a blade support 18, which, in turn, is supported on two counter supports 19, i.e. long rails that are parallel and disposed on top of the path of motion of the splitting piston. The rails are disposed at a distance from one another so that a slit is ormed between them, from which the switching peg 20 attached to the splitting piston 1 extends to the hole disposed in the blade support 18. In this manner, the blade 4 moves back and forth together with the splitting piston. In cutting, the forces directed to the blade 4 do not, however, affect the splitting piston, like in the embodiment of Fig. 1. In this embodiment, as the blade 4 is supported on the counter supports 19 by means of the blade support 18, the splitting piston is not subjected to the any kinds of transverse forces. The rest of the structure and operation of the embodiment as shown in Fig. 2 is similar to the one shown in the embodiment of Fig. 1, so they are not repeated in this connection. The invention is not limited merely to the examples referred to above; instead many variations are possible within the scope of the inventive idea defined by the claims .

Claims

CLAIMS 1. A cutting and splitting device for cutting and splitting tree trunks, the cutting and splitting device including a cutting tool for cutting the tree trunk and a splitting tool for splitting the tree trunk having a splitting piston (1) , a splitting blade (2) and a power unit (3) for moving the splitting piston, for pushing the piece of wood already cut by the cutting tool through the splitting blade using the splitting piston, c h a r a c t e r i s e d in that the cutting tool includes a straight, slitting cut-off blade (4) attached to the splitting piston (1) and movable together with it, the cutting blade edge (5) of which cut-off blade is at an oblique angle with respect to the path of motion of the splitting piston and which is in parallel to the path of motion of the splitting piston; and a fixed trunk support (6) for supporting the trunk (7) in the transverse direction with respect to the path of motion of the splitting piston as the cut-off blade cuts off the trunk. 2. The cutting and splitting device as defined in claim 1, c h a r a c t e r i s e d in that the cut-off blade (4) forms a fixed complex with the splitting piston (1) . 3. The cutting and splitting device as defined in claim 1, c h a r a c t e r i s e d in that the cut-off blade (4) is coupled to the splitting piston (1) to be movable together with it. 4. The cutting and splitting device as defined in any one of claims 1-3, c h a r a c t e r i s e d in that the cut-off blade (4) extends vertically upward from the upper surface of the splitting piston (1) . 5. The cutting and splitting device as defined in any one of claims 1-4, c h a r a c t e r - i s e d in that trunk support (6) includes supporting surfaces (8) on both sides of the mobile cut-off blade (4) so that the cut-off blade extends from between the supporting surfaces as the trunk is being cut. 6. The cutting and splitting device as defined in any one of claims 1-5, c har a c t e r i s e d in that trunk support is formed by an angle support that supports the trunk in the direction of motion of the splitting piston and upwards. 7. The cutting and splitting device as defined in any one of claims 1-5, c har a c t e r i s e d in that the trunk support is formed by an aperture with its edges that defines the maximum diameter of the trunk being cut. 8. The cutting and splitting device as defined in any one of claims 1-7, c ha r a c t e r i s e d in that the cutting and splitting device includes an adjustable limiter (9) for determining the cut length of the trunk. 9. The cutting and splitting device as defined in any one of claims 1-8, c ha ra c t e r i s e d in that the cutting and splitting device includes guide means (10) for turning the cut piece of trunk and guiding it lengthwise to face the splitting piston (1) . 10. The cutting and splitting device as defined in any one of claims 1-9, c ha r a c t e r i s e d in that the cutting and splitting device includes a switch (11) for controlling the starting of the simultaneous splitting and cutting movement. 11. A cutting and splitting device for cutting and splitting trunks, the cutting and splitting device including a cutting tool for cutting the trunk and a splitting tool having a splitting piston (1) , a splitting blade (2) and a power unit (3) for moving the splitting piston and for pushing the cut piece of wood through the splitting blade using the splitting piston, cha r a c t e r i s e d in that the cutting tool includes a fixed and straight slitting cut-off blade (4) attached to the device body, the cutting blade edge (5) of which cut-off blade is at an oblique angle with respect to the path of motion of the splitting piston and which is in parallel to the path of motion of the splitting piston; and a trunk support (6) connected to the splitting piston (1) and movable together with it for supporting and pressing the trunk (7) against the cutoff blade in the transverse direction with respect to the path of motion of the splitting piston.