FI105523B - Method and arrangement for cutting off a tree trunk - Google Patents

Description

105523

Method and equipment for trunk cutting

The invention relates to a method according to the preamble of claim 1 for cutting a tree trunk by means of a motor-operated cutting blade adapted to a logging apparatus which can be coupled to a mobile working machine, such as a multifunctional harvester. The invention further relates to an apparatus according to the preamble of claim 6, preferably in a moving machine, such as a multifunction harvester, for connecting a log harvester for cutting a log 10.

The harvester head of off-road machines, such as multifunctional harvesters, is most commonly used to cut the tree trunk, where a circular, continuous blade chain rotates the blade flange. 15 The blade chain is rotated by means of a motor communicating with it, which is usually controlled by a pressure medium such as hydraulic oil. The blade flange is fed to perform a cut against the wood by means of an actuator, typically a cylinder, which is also controlled by the pressure of the pressurized medium supplied thereto to apply a feed force to the wood frame to cut the movable blade chain into the wood material.

In accordance with the prior art, the feed speed of the harvester head trimmers is typically set at a constant rate. In this case, the feed speed and the permissible feed force of the mouth have to be adjusted so low that the cut-off saw can also be sawed on trees with high sawing resistance, for example when cutting thick trees. Typically, the sawing resistance is greatest in the middle stages of sawing, when the saw chain has advanced to the center of the tree body, whereby the saw chain extends substantially through the cross-sectional diameter of the tree frame, whereby the length of the sawing point is also greatest. If the saw resistance increases too much, the blade chain speed slows down, the cutting ability decreases and the jam can stop completely. As a result of standardized brains, especially during the initial and final stages of sawing and when cutting thin trees, the feed rate 35 is unnecessarily low, and thus, for example, the cutting time is extended.

As such, control systems for cutting saws are known which measure the feed pressure of the cutting medium 105523 to the cutting saw to determine the cutting resistance and as the feed pressure rises above the set limit, the cutting blade feed rate is slowed Such a control system is disclosed in US 4,083,291, whereby early-stage sawing can be accelerated. Control systems are also known which measure the rotational speed of the cutting saw by measuring the rotational speed of the saw motor and adjusting the maximum pressure of the pressurized medium supplied to the actuator to maintain the rotational speed substantially constant as the saw resistance changes. Such a control system is disclosed in Fl 97918, whereby both initial and end-stage sawing can be accelerated.

15 At work sites, the multifunctional harvester grabs the vertical tree frame by means of harvester head support members, cuts the tree frame, cuts it, and typically pruners mounted on the support members prun the tree frame while feeding it horizontally through the harvester head. Thus, in sawing 20, the tree trunk is usually handled horizontally, whereby it is held in position by means of support members mounted on the harvester head. During the sawing, the part of the tree trunk to be cut off is not supported but is attached without support to only the part of the tree trunk that remains on the harvester head. A notable problem is that during the cutting, the wood frame, in particular the cutting point, is subjected to considerable bending forces, which cause cracking in the longitudinal direction of the wood frame from the cutting point. These fissure defects cause considerable, e.g. problems related to the quality and further processing of the wood at different stages. In particular, crack damage 30 has been found to occur at the stage of cutting the wood, when about a third of the woody trunk remains and in the case of relatively large diameter tree trunks.

With prior art control systems, such as the system of US 35 4,083,291, crack damage may even increase as the cutting speed of the cutting saw is slowed down during the final stage of sawing. A system according to Fl 97918 with which a constant; At the same time, the speed of the saw can be accelerated, but is mainly intended to reduce the overall time of the saw and to take into account changes in conditions during the saw. There is also known a solution according to patent specification F 102236, wherein the position of the blade 5 of the cutting saw is indicated by a position indicator, whereby the movement of the blade can be limited to the necessary amount, depending on the diameter of the tree trunk to be cut. The purpose of the solution is to determine the time of color marking based on location and to minimize overall sawing effect.

10

It is an object of the present invention to overcome the above problem and to provide a novel method and apparatus applying the method. To accomplish this purpose, the method according to the invention is characterized by what is set forth in the character-15 character part of claim 1. The apparatus according to the invention is characterized by what is stated in the characterizing part of claim 6

The invention is based on the idea that, in particular, the cutting power of the cutting saw is controlled depending on where the cutting saw is located during cutting 20 relative to the tree trunk to be cut. In particular, the invention is based on the idea that the feed force of the saw can be controlled in an effort to achieve an optimum sawing action, especially during the final third of the sawing, particularly to reduce crack damage.

25

The invention provides considerable advantages in the use of the apparatus according to the invention, particularly in the prevention of end-stage cracking damage. In this case, the feed force can be controlled in a desired manner and in a manner different from the various standard setting adjustments, whereby the cut-off event can be managed with considerable versatility and also optimized for the sawing position depending on the position of the cut saw.

A further advantage of the invention is that it can be easily applied to existing harvester heads by making the necessary changes to the control system of the multifunction harvester and to the control programs stored in the control system to implement the control algorithms. A further advantage of the invention is that it can also supplement the control system 4 105523 disclosed, for example, in Fl 97918, by switching from a constant speed control of a saw motor to a feed force control in a desired manner and at a desired stage. By means of the invention, the control can take into account the thickness of the tree trunk, and at the same time schedule the control measures for the saw, especially in the area where the tree trunk with a given diameter dimension develops crack lesions.

A particular advantage of the invention is that the control can be carried out by very simple methods, for example by tabulation or calculation formula 10, using inputs such as the diameter of the tree trunk and the position of the blade flange and the output being a control signal for controlling the actuator pressure level.

The invention will now be described in more detail using, as an example, a harvester head that can be coupled to a work machine used as a harvester, such as a multifunction harvester, with reference to the accompanying drawings, in which: Figure 1 is a perspective view of a prior art harvester Fig. 2a is a plan view of the harvester head support members, Fig. 2b is a plan view of the harvester head cutter, Figures 2c and 2d show the computing elements and control means according to the invention, and Fig. 3 shows a preferred control system for adjusting the feed force.

With reference to Figure 1, the known harvesting apparatus, or harvester head 1, also referred to in the following description as the carding apparatus, comprises a frame structure 2. For connecting the pruning apparatus 1 to a boom of a known working machine, such as a multifunctional harvester (not shown) With reference to Fig. 1, the apparatus 1 is shown substantially vertical (arrow Z), with the hinge 2b and the attachment structure 2a, the frame structure 2 is arranged in a substantially horizontal (arrow X) direction; rotate around. Further, fastening and rotating means 2c, such as a rotator 2c, are provided in the upper part of the mounting structure 2a for securing the equipment 1 to the end of the working machine boom.

The apparatus 1 further comprises a first bracket member 3a and a second bracket member 3b, which are articulatedly fixed to the frame structure 2 by means of pivots 5a and 5b. The apparatus 1 further comprises traction means 6a and 6b, preferably traction sheaves 6a and 6b, mounted on the frame structure 2 by means of articulations 7a and 7b, which engage against the pruning tree trunk and pull 15 along the pruning blades 4a and 4b to prune them. In pruning, the tree trunk is moved substantially horizontally along its length.

In the position shown in Figure 1, the apparatus 1 is located when the apparatus 1 20 engages a substantially vertical (arrow Z) tree frame, with support members 3a and 3b and drive wheels 6a and 6b preferably in their outermost position for positioning the tree frame against the support surface 2d.

The apparatus 1 further comprises a cutting saw 8 for cutting an upright and pruning tree trunk. The pruning saw 8, preferably comprising a motor chain M a rotatably driven by a motor M, preferably a hydraulic motor M, and adapted to rotate the blade flange 8b, also performs the cutting of the tree trunk into defined lengths being rotated about 90 degrees about the pivot 2b, with the support members 3a and 3b oriented substantially vertically (arrow Z). The position of the blade flange 8b is controlled by actuator means, typically a pressure medium actuated cylinder 35 (actuator S in Figure 3). Sawing is performed with the blade chain 8a while the blade flange 8b moves through the wood frame in its transverse direction. In the position of Figure 1, the cutting saw 8, preferably a chain saw, is arranged to rotate about a substantially vertical (arrow Z) direction 6 105523. Further, in Fig. 1, the blade flange 8b is shown in a position where it is in the final stage of sawing. In the position prior to the initial phase of sawing, the blade flange 8b is disposed in the housing 8c in the shield of the frame structure 2.

5

The pruning apparatus 1 of Fig. 1 further comprises an additional pruning member 4d which, by means of articulation 5d, is pressed against the tree trunk by its own weight or, for example, by a spring force or an actuator such as a pressure medium cylinder. The apparatus 1 also comprises a measuring wheel 15 10 for measuring the length of the tree trunk during pruning and an articulation 5c of a lower bracket member 3c attached to the trunk 2 to support and support the tree trunk 4c from at least one side.

The apparatus according to the invention comprises sensor means for determining the position of the cutting saw 8 relative to the tree trunk to be sawn, at least during sawing. It is clear that the sensor means can also be applied to position detection in other situations. The following sensor means for position determination are described in more detail below.

Referring to Figures 1 and 2a, according to a preferred embodiment of the invention, said sensor means comprise first sensor means 11 adapted for pivoting 5a of at least one support member 3a on the harvester head 1 for determining the position of the support member 3a during pruning. The position of the support member 3a is controlled in a manner known per se, for example by means of a fluidized-bed cylinder 9. This position is defined, for example, as the angular position α- | of the support member 3a with reference reference position ar, which reference position 30 may vary. This angular position ai can also be used to determine the diameter D of the tree trunk, whereby a certain angular position corresponds to a certain diameter. Preferably, the angular position is computationally directly proportional to the diameter, for example D = ai k and then D = f (ai, k) where k is a coefficient. However, the diameter calculation assumes that the tree trunk S is positioned against the support surface 2d.

Referring to Figures 1 and 2b, in accordance with a preferred embodiment of the invention, the aforesaid sensor means further comprise second sensor means 12 arranged in connection with the cutter saw to determine the position of the cutting saw 8 at least during sawing. This position is defined, for example, as the angular position βι of the saw flange 8b with respect to the reference reference position βΓ, which may vary.

Furthermore, the sensing means comprises counting means 13 for communicating with the first sensor members 11 and the second sensor members 12 by means of communication links 11a and 12a according to the position of the support member 3a, wherein the position of the saw blade 8b and especially the cutting blade 8a 2b) with respect to the tree trunk S is determined on the basis of said diameter and the position of the saw flange 8b. The position, for example the parameter p-j, can be determined computationally (represented by the function ρι = ί (βι, α * |) in Fig. 2c) based on the geometry and trajectories of the saw flange 8b and the supporting member 3a used. The calculating means 13 transmit the position information, for example electronically, to the control means 14 to be described later using the communication link 13a. It is clear that the position of the saw flange 8b can also be determined by the counting means 13 even when it is outside the tree trunk 20 S, approaching the tree trunk S or moving away from the tree trunk S.

The apparatus according to the invention further comprises the necessary actuator means for feeding the cutting saw 8 through the tree trunk S and the controlled cutting power 8 for controlling the cutting force during sawing. These actuators are described in more detail below. It is clear that these actuator tools can be used in operations other than sawing.

Referring to Figures 1 and 3, according to a preferred embodiment of the invention, these actuator means comprise a pressurized fluid actuator C for changing the position of the cutting saw 8, more specifically the saw flange 8b, and providing a feed force to the actuator C from the pressure medium P. Further, the actuator means 35 comprise control means 20 communicating with the control means 14, which control the pressure of the pressure medium based on the control signals provided by the control means 14. As a control valve in the 30-cylinder ... line, the LS preferably has a pressure proportional valve, a pressure valve known per se, whose outlet pressure can be electronically controlled to control the pressure of the pressure medium supplied to the actuator C.

Figure 3 also shows a preferred control system which can be used to control the actuator C and other functions of the harvester head. The system is presented in the form of a hydraulic diagram showing the main components of the system. Hydraulic fluid is most preferably used as the pressure medium in the control system. The hydraulic components of the control system are mainly located on the harvester head 1 of the multifunction brush 10. The control system comprises a line L connected to a source of pressure medium, such as a hydraulic pump P. The line L passes to a stop valve 21 which is compressed horizontally. The restriction valve 21 limits the pressure medium flow to the motor M so that the maximum permissible engine speed is not exceeded. The motor M 15 rotates the blade chain fitted to the blade flange at the desired speed. The pressure medium is also guided along the line L to the control means 20 for controlling the pressure of the pressure medium under the control of the control means 14. Pressure medium is also passed from line L through start valve 23 to engine M control valve 24 along control line LO, whereby pressure medium 20 opens control valve 24. When control valve 24 is open, pressure medium 21 is fed through control valve 24 to engine M, rotate. From the motor M, the pressure medium is supplied to the pressure medium tank T along the return line LT. In addition, the motor M is provided with a safety valve 25, 25 which allows the pressure medium to pass through if the pressure in the return line LT is increased by the valve 25 above a preset value.

The start valve 23 of the motor M is controlled in a manner known per se. In the drawing, the start valve 23 is marked in a position where the control of the start-up valve 23 is off and the motor M is rotating. When the control of the start valve 23 is turned on, the start valve 23 moves to the right position. The control valve 24 in line LO then stops and the control valve 24 closes while stopping the motor M. The pressure medium is led from the control line LO 35 of the control valve 24 through the start valve 23 to the pressure medium tank T.

Referring to Figures 3 and 2d, according to the invention, the control means 14 are arranged to control the feed force by controlling the actuator means, whereby the feed force 9 105523 is determined during the sawing based on the position of the cutting saw 8. This determination is accomplished by means of a control algorithm 16 stored in said control means 14, which according to a preferred embodiment comprises an input representing the position 5 of the saw flange 8b in the tree trunk S, which can be supplied from the counting means 13 and an output force F- | a descriptive parameter for controlling the actuator means. The actuator means, more particularly the control means 20, are typically controlled by an electrical signal, such as a current signal or a voltage signal, using the communication link 14a. The control means 14 also carry out the necessary steps for converting the parameter values into electrical signals and vice versa. The control algorithm 16 used is formed, for example, by a table, a function, a calculation formula, or also a combination of the relationship between the position p-j and the feed force F-j (or alternatively pressure medium pressure in the cylindrical line LS of Figure 3). According to a very simple embodiment, the dependency is formed by a dependency table into which the user of the equipment has input the desired values for the parameters. In Fig. 2d, the control algorithm 16 is shown in the form of a curve, but it is clear that the curve may also be knee-deep or linearly point-to-point. It is also clear that the control algorithm can be generated for only part of the position p- |. The control algorithm 16 is further influenced by the diameter dimension D of the tree trunk S, as well as by the quality characteristics of the tree trunk and the conditions prevailing during sawing, which can be taken into account by means of parameters. The diameter D of the tree trunk S is obtained from the first sensor means 11 and parameters describing the conditions can be entered by the user into the system.

According to an advantageous embodiment of the invention, the aforementioned calculating elements and the aforementioned control means are formed on the own and known control automation means of a used working machine, for example a multifunction harvester, for controlling the working machine and the harvester head. Then you can. uses control automation elements to generate and input the aforementioned dependency table and to store the control algorithm 16. In this case, the control automation means may further control the control means 20 in a desired manner, for example in Fig. 2d, for example at the initial stage AV and in the middle stages KV. According to a preferred embodiment of the invention, the control algorithm 16 105523 10 is used especially in the final sawing phase to control the LV feed force to prevent crack damage. According to a preferred mode of adjustment, the control means 14 are arranged to control the actuator means such that the feed force is substantially controlled during the last third of the sawing (corresponding to the final stage LV) as shown in Figure 2d. According to a preferred control method, the feed force exerted by the blade chain 8a on the wood frame S is reduced during the initial sawing phase AV and the feed force is increased during the final sawing phase LV.

10

The feed direction of the saw flange 8b is controlled by the flange direction valve 31 of the control elements 2 which is marked in the drawing in the cut-off position, i.e. the flange 8b is fed against the wood frame S to cut the wood frame S. When the tree trunk is cut off, the control system 15 controls the directional valve 31 of the blade flange 8b, whereupon the flange 8b moves back to its original position under the action of the pressurized fluid and the pressure medium in the cylinder side LS is fed to the pressure medium tank.

The invention is not limited to the above embodiment only, but may be modified within the scope of the appended claims. The computing means 13, the control means 14 and the control automation means may be formed, at least in part, by a data processing device used for controlling the implement, such as a computer or programmable logic, further comprising memory means 25 known per se for storing the dependencies and control algorithms described above. It is understood that the hardware can be divided into a plurality of interconnected subsystems in a manner known per se, depending on the needs of different applications, but in this disclosure, for example, the control means 14 are illustrated as a single unit.

*

Claims (12)

A method of cutting a tree trunk with a motor-driven cutting saw arranged in a drive device (1) which can be coupled to a preferably movable working machine, such as a multi-phase harvester, in any method: - the tree trunk (S) is poured into the driving device (1), - said cutting saw (8) is measured with a controlled feed force through the tree trunk (S) and simultaneously the tree trunk (S) is cut with said cutting saw (8) to cut the same, and - the position of the cutting saw (8) relative to the tree trunk (S) to be cut is determined at least during the cutting, characterized in that: - the feeding force is controlled by a control algorithm (16), which comprises at least a correlation between said position and said feeding force, describing table, function, calculation schedule or a combination of these. 2. A method according to claim 1, characterized in that the feeding force is controlled by the said control algorithm (16), which further takes into account also the diameter measurement (D) of the tree trunk (S) and preferably also the quality characteristics and conditions of the tree trunk during the sawing. A method according to claim 1 or 2, characterized in that the feeding force is controlled during the cutting substantially during the last third. Method according to Claim 1 or 2, characterized in that the feeding force is reduced at the initial stage (AV) and the feeding force is increased at the final stage (LV). 5. A method according to any of claims 1-4, characterized in that the feeding force is controlled at least by the cutting of a part of the tree trunk (S) supported in the horizontal direction in the drive device (1) to prevent crack damage and as a result of said breakage. tree trunk (S) without the support of said device (1). Apparatus in a drive device (1) which can be coupled to a preferably mobile working machine, such as a multi-phase harvester, for cutting a tree trunk, comprising: - a motor-driven cutting saw (8) adapted for cutting the tree trunk (1) S) by sawing, - in force-transmitting connection with cutting saw (8) existing actuators (C, 20, 30) to feed cutting saw (8) through the tree trunk (S) and to maintain the feeding force of cutting saw (8) in a controlled manner during cutting - sensors (11, 12, 13) for determining the position of the cutting saw (8) relative to the tree trunk (S) to be said, at least during the sawing, and - guiding means (14, 16) for setting the feeding force by controlling the actuators (C, 20, 30), characterized in that - the control means (14) are arranged to control the feeding force by means of a control algorithm (16) stored in the control means (14), which comprises at least one said position described another parameter and which output at least one said power supply descriptive parameter for controlling the actuators (C, 20, 30), and that said control algorithm (16) comprises a further correlation between said position and said power supply descriptive table, function, calculation schedule or a combination of these. Device according to claim 6, characterized in that the transducer (11, 12, 13) comprises: - at least one supporting means (3a, 3b, 3c) adapted in the drive device (1) for holding the tree trunk (S) and which is provided with first sensor (11) for determining the position of said support means (3a, 3b, 3c), 105523 - in conjunction with the cutting saw (8), second sensor (12) adapted to determine the position of the cutting saw (8) at least during the say, and - with the first and second sensor means (11, 12) interconnecting calculating means (13) to determine the diameter (D) of the tree trunk (S) at the base of the position of said carrier (3a), 3b, 3c), to determine said position on said base of said diameter (D) and said position, and to convey said position regarding information to said control means (14). Apparatus according to claim 6 or 7, characterized in that the actuators (C, 20, 30) comprise: - a pressure medium driven actuator (C) for changing the position of the cutter saw (8) and for providing the feeding force by means of of the pressure of a pressure medium to be measured from a pressure source (P) to the actuator (C), - control means (20, 30) interconnected with the control means (14) to control the pressure of said pressure medium in a controlled manner by means of the control means (14). Device according to claim 8, characterized in that the control means (20, 30) comprise a pressure proportioning valve (30) known per se for controlling the pressure of the pressure medium to be measured in said actuator (C). Device according to any one of claims 6 to 9, characterized in that the control algorithm (16) further comprises as input a parameter of the tree trunk (S) descriptive parameter (D) and preferably also the quality characteristics and conditions of the tree trunk during said description of the tree trunk. to observe these computationally. Device according to any of claims 6 to 10, characterized in that the control means (14) are arranged to control the actuators (C, 20, 30) so that the feeding force is controlled substantially during the last third part of the say. 105523 Apparatus according to any one of claims 6 to 11, wherein the working machine comprises control automatic means for controlling said working machine and said driving device, characterized in that said calculating means (13) and said control means (14) are formed in said control automatic means.