Classifications

• • A—HUMAN NECESSITIES
  • A01—AGRICULTURE; FORESTRY; ANIMAL HUSBANDRY; HUNTING; TRAPPING; FISHING
  • A01G—HORTICULTURE; CULTIVATION OF VEGETABLES, FLOWERS, RICE, FRUIT, VINES, HOPS OR SEAWEED; FORESTRY; WATERING
  • A01G23/00—Forestry
  • A01G23/02—Transplanting, uprooting, felling or delimbing trees
  • A01G23/095—Delimbers
  • A01G23/097—Delimbers having a fixed delimbing head

Definitions

• the present invention relates to the field of limbing of tree trunks.
• a machine For the limbing of tree trunks, a machine is commonly used comprising two drive rollers used to grip the tree trunk in order to pass it through a system of knives ensuring the limbing of the tree trunk.
• Known delimbing systems include pivoting curved knives which grip the trunk and remove the branches as the trunk scrolls.
• the knives which are controlled independently of the rollers, are arranged in pairs, the knives of each pair closing around the trunk.
• the object of the invention is to remedy this drawback and, to this end, it proposes an improved delimbing system which ensures a considerably increased delimbing yield.
• a delimbing device comprising a first and a second pair of curved knives arranged to be able to move in a movement of closing and opening movement in two parallel planes and a fifth curved knife supported by the frame.
• the knives of the second pair are connected to the respective knives of the first pair so that the movements of the knives of the two pairs are synchronized and that, when said first and second pairs of knives are closed, the five knives circumscribe a closed contour and are in practically maximum contact with the entire circumference of a tree trunk.
• the knives of the second pair can be mounted to pivot between a first position in which they are retracted under the fifth fixed knife and a second position in which they partially overlap the knives of the first pair.
• the moving tree trunk is optimally circumscribed by five knife blades also ensuring the centering of the trunk, and this for a wide range of trunk diameters .
• the tree trunks have a conical shape and that their diameter varies over their entire length.
• a second aspect of the invention relates to optimizing the inclination of the axis of the support arms of the drive rollers.
• This optimization of the angle of inclination of the axes makes it possible to combine the opening of the support arms of the rollers, the formation between these rollers of a V all the more marked as the opening of the arms is large, which has the advantageous effect of allowing the rollers to take up a significant part of the weight of the wood and thus reducing the friction of the wood on the knives.
• Figure 1 is an elevational front view of a machine comprising a delimbing device according to the invention
• Figure 2 illustrates an alternative embodiment of the machine shown in Figure 1;
• Figure 3 is a plan view of the delimbing device according to the invention
• Figure 4 is a schematic perspective view of the device of Figure 3;
• Figures 5 to 10 illustrate the closing movement of the knives in the limbing device of Figure 4;
• Figure 11 shows a pair of bogie drive rollers
• FIG. 12 is a diagram of a hydraulic circuit for clamping knives or rollers respectively.
• Figure 13 is a diagram of an independent hydraulic circuit for driving wood by the rollers.
• Figure 1 there are, mounted on a frame 10, two drive rollers 21 and 22, and a delimbing device 30 according to the invention.
• Figure 2 shows a similar machine, but in which are mounted four drive rollers 21-24, the delimbing device 30 being the same as in Figure 1.
• a trunk shaft is placed between the rollers 21 and 22 and these rollers drive the trunk and pass it through the delimbing device 30.
• the drive rollers are supported by support arms 27, 28 articulated on axes 25 , 26 which are inclined with respect to a horizontal plane and inclined laterally with respect to the vertical median plane of the delimbing device 30.
• the drive of the woods is carried out, on each side, by a pair of driving rollers 21 and 23 and respectively 22 and 24.
• Each pair of rollers is mounted on a type of support bogie 54 and respectively 55.
• Such a pair of rollers on a bogie is shown in perspective in FIG. 11.
• Each bogie therefore supports two rollers whose axes are parallel and it is articulated on a support arm 56 or respectively 57 by means of an axis 58 or respectively 59.
• Each of the bogies 54 and 55 thus have a possible rotational movement relative to the corresponding support arm.
• the axis of rotation 58 or 59 is parallel to the axes of the corresponding rollers 21 and 23 or 22 and 24.
• the support arms are, as illustrated in FIG. 1, articulated on inclined axes 25, 26.
• Each roller may have a drive motor, not shown. It can also be provided as in FIG. 11 that only one roller 23 of each pair is driven and that the other is driven by the first by any suitable transmission means, for example a chain 61, represented schematically by a line. mixed, which engages in the cooperating teeth 62 and 63 carried by each of the rollers.
• a suitable transmission means for example a chain 61, represented schematically by a line. mixed, which engages in the cooperating teeth 62 and 63 carried by each of the rollers.
• the bogie can be oriented at any time in order to keep in contact the two rollers of each pair with the wood.
• the clamping force is constantly divided between these two rollers and any obstacle encountered by a roller has its amplitude divided at the support arm.
• each roller is therefore reduced with the effect of reducing the deterioration of the wood surface.
• the tensile force of the rollers is practically doubled, which is important for non-linear trunks like those of hardwoods.
• Figures 3 and 4 show in particular a delimbing device according to the invention.
• Figure 3 shows a plan view of the device, in the open position
• Figure 4 shows a schematic perspective view of this device in a partially closed position, circumscribing an opening having an average diameter.
• the device according to the invention comprises five curved knives.
• Two large knives 31 and 32 consist of two arms 33 and 34 having a boxed structure and carrying respectively two-edged blades 35 and 36.
• the arms 33 and 34 are fixed on support tubes 37 and 38 intended to receive axes of rotation.
• the arms 33 and 34 of the knives are interconnected by a connecting rod 39.
• These large knives 33 and 34 are intended both for the operations of gripping the trunks and act like a gripping grapple, thus than delimbing operations.
• the rod 39 acts crosswise between the knives and thus ensures the synchronization of their closing movements. It is thus impossible to close one knife without the other.
• Two small knives 41 and 42 consist of two arms 43 and 44 carrying two blades with two cutting edges 45 and 46, the arms also being fixed on support tubes 47 and 48 intended to receive axes of rotation.
• the arms 43 and 44 of these small knives are connected to the arms 33 and 34 of the large knives by connecting rods 51 and 52 so as to synchronize the closing movements of the small knives 41 and 42 with the closing movements of the large knives 31 and 32
• the small knives 41 and 42 are arranged so that their arms move above the arms of the large knives 31 and 32.
• the small knives 41 and 42 are used for delimbing operations.
• a fifth curved knife 53 is frontal and fixed. It is fixed to the machine frame and extends over the small knives. The fixed knife 53 is used for delimbing operations.
• the movements of the large and small knives, as well as the drive rollers are controlled by a control device not shown. Thanks to the synchronization of the small knives 41 and 42 with the large knives 31 and 32, the first always follow the movement of the large knives and this allows the five knives of the assembly to form, for delimbing operations, a closed contour around the trunk, thus circumscribing contours very close to the circle, but of different diameters as illustrated in Figures 5 to 10.
• the large knives 31 and 32 are open and the small knives 41 and 42 are retracted below the fixed knife 53, transforming the device into a gripper where the large knives form a grapple used for loading wood ( Figures 5 and 6).
• the large knives 31 and 32 are controlled to close, gradually driving the small knives, the cutting blades 43 and 44 of which are placed between the cutting blades 33 and 34 of the large knives and the front knife 53 ( Figures 7 to 10).
• the closing of the swivel knives allows to circumscribe continuous contours of different diameters.
• the arrangement according to the invention ensures that the cutting blades are always in maximum contact with the entire circumference of the tree trunk during the operations of lopping.
• the axes of the support arms of the drive rollers are inclined.
• the inclination of the axes 25-26 of the support arms of the drive rollers is optimized so as to allow the rollers not only to drive the tree trunks, but also to resume a significant part of the weight of the wood.
• the axes of the support arms of the drive rollers are preferably inclined by approximately 76 e with respect to a horizontal plane and inclined laterally by approximately 5 ° with respect to the vertical median plane of the delimbing device 30. Thanks to this optimization, when they open, the rollers form between them a V all the more marked as the opening and therefore the diameter of the tree trunk are large.
• the clamping force of the rollers is broken down into two distinct components: a horizontal component exerting the clamping and a vertical component which takes up a significant part of the weight of the wood.
• the aforementioned optimized inclination has the effect of favoring the opening angle V of the rollers while minimizing the angle of shifting of the rollers. Thanks to the fact that the wood is thus carried by the rollers, the friction of the wood on the knives is greatly reduced, and this results in less loss of energy and an increase in the efficiency of the delimbing machine.
• it is advantageous to provide at least two clamping circuits namely:
• the hydraulic clamping pressures of these circuits are preferably to be adjusted, advantageously separately for each circuit and according to different parameters: diameter of the wood, essence of the wood, working phase (starting and stopping of the scrolling of the woods, etc.).
• FIG. 12 a measurement management system has been illustrated which consists in using hydraulic valves of the open-closed type (ON / OFF) to vary the clamping pressure which, depending on the circuit, will be applied to the knives or the rollers .
• the hydraulic line 70 of the illustrated circuit has a constant pressure or flow and is supplied from a source of hydraulic medium under current pressure, not shown. This line is connected to a closed-center valve 71 which communicates with hydraulic cylinders 72 and 73.
• the pistons 74 and 75 of these cylinders make it possible to tighten or loosen the knives or rollers.
• a hydraulic-gas accumulator 76 On the line joining the valve to the side allowing the tightening of the jacks is a hydraulic-gas accumulator 76 as well as a pressure measurement sensor 77, permanently informing an electronic unit, not shown, of the clamping pressure.
• the electronic unit controls by a calibrated pulse the opening of the valve 71 which injects a small volume of oil in the circuit of tightening, the pressure increasing slightly while obeying the equations of behavior of the compressed gas in the accumulator.
• the pressure is again measured and compared with the setpoint, and the control pulses follow each other if necessary. Conversely, a volume of oil is subtracted by the valve if the pressure is too high.
• a hydraulic valve 79 can be placed on the line towards the accumulator in order to isolate it from certain moments.
• the side opposite the tightening of the jacks is connected to the oil return so as not to impede the elastic functioning of the system, and this thanks to the nature of the valve 71 itself, or else by an additional valve 78.
• the clamping of the drive rollers must meet a double requirement: a minimum clamping pressure is required in order to damage the surface of the woods to be driven to a minimum, but on the other hand, if the wood's driving force must increase (more important, heavy wood,), it is clear that a too low clamping pressure gives rise to slippage and therefore also to damage to the surface of the wood.
• an independent hydraulic supply circuit for driving the wood can be supplied from a source of hydraulic medium under current pressure, not shown, which can be the same as that supplying the clamping circuits of the knives and rollers previously described.
• the supply line 80 of the circuit is however independent of the supply line 71 of the clamping circuit shown in FIG. 12.
• the supply circuit shown in FIG. 13 comprises for example a pressure sensor 81, which can measure the pressure necessary for driving the wood, and a supply valve 82 which supplies the drive motors 60 of the drive rollers.
• the electronic unit permanently informed of the pressure measured by the sensor can, when it notices an increase in pressure, act on the set value of the clamping pressure of the drive rollers by the control device, and so , correct the tightening of the drive rollers and therefore their adhesion. It is therefore an anticipatory traction control system.
• the embodiments described above are examples given by way of illustration only. Variants of execution and modifications can be made by those skilled in the art without departing from the spirit of the invention and without departing from the scope of the claims below.

Applications Claiming Priority (3)

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• 1998
  • 1998-09-03 BE BE9800647A patent/BE1013070A3/fr not_active IP Right Cessation
• 1999
  • 1999-09-03 AU AU57218/99A patent/AU5721899A/en not_active Abandoned
  • 1999-09-03 EP EP99944174A patent/EP1109437A1/de not_active Withdrawn
  • 1999-09-03 WO PCT/BE1999/000116 patent/WO2000013485A1/fr not_active Application Discontinuation

Non-Patent Citations (1)

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