WO2007066161A1

WO2007066161A1 - Tree feller-chipper

Info

Publication number: WO2007066161A1
Application number: PCT/HU2006/000107
Authority: WO
Inventors: Mátyás LIKER; György LIPUSZ; Árpád OLÁH; Imre TAKÁCS; János PÜSKI
Original assignee: Optigép KFT.
Priority date: 2005-12-09
Filing date: 2006-12-06
Publication date: 2007-06-14
Also published as: HU227645B1; HU0501147D0; EP1962576A1; HUP0501147A2

Abstract

Feller-chipper for harvesting forests, primarily planted forests and particularly energy plantations, comprising a mobile frame structure or a frame structure mounted on a tractor, and a guiding element attached to the frame structure. The machine further comprises a cutting unit coacting with the guiding element. The machine still further comprises a hauling-in and feeding unit adapted for conveying the tree from the cutting unit to the chipper unit, and further comprising a tangentially attached discharge chute connected to the chipper disc. The invention is essentially characterised by that the hauling-in and feeding unit consists of a hauling-in portion extending over the saw discs (9), the hauling-in portion being adapted for keeping the trees (20) in upright position and conveying them to the chipper unit.

Description

Tree feller-chipper

Tree feller-chipper for harvesting forests, primarily planted forests and particularly energy plantations, comprising a mobile frame structure or a frame structure mounted on a tractor, and a guiding element attached to the frame structure, where the guiding element is implemented as two oppositely rotated guide screws adapted for enclosing tree trunks at a height proximate to the centre of gravity thereof, with the axles of the guide screws being attached to a support beam attached to the frame structure. The machine further comprises a cutting unit coacting with the guiding element, implemented as two counter-rotating saw discs attached to the frame structure rearwards from the guiding element, and also comprises a hauling-in and feeding unit adapted for conveying the tree from the cutting unit to the chipper unit, with a chipper disc having rotary knives and a stationary knife being disposed inside the chipper housing of the chipper unit, and with the chipper housing comprising an inlet opening facing the feeding unit, and further comprising a tangentially attached discharge chute connected to the chipper disc.

Industrial-scale energy forests, and especially energy plantations account for a significant share of renewable energy production. By the term "energy plantation" we mean 3 - to 4-year-old planted forests, whereas the term "energy forest" is used referring to planted forests comprising trees older than 2-4 years. The technology and economics of short rotation plantations has now become an established field. Experience shows that the optimal growth period for energy plantations is from two to four years, depending on the applied species. By the end of this period saplings will have grown to trees with a trunk diameter of 8-10 cm and a height of 6-8 m, standing in rows, with uniform distances between individual trees due to planned planting. Different methods have become widespread for harvesting energy plantations. According to one of these methods the plantation is harvested before the end of the optimal growth period (at the age of 1-2 years), when the trunks have not yet become too thick. In this case, reinforced mobile choppers are applied. The disadvantage of this method is that the genetic potential of the applied tree species cannot be fully exploited. According to another method, felling and chipping are carried out in two distinct steps. Patent description DE 35 36 459 discloses a method and apparatus for the mechanised harvesting of tree stands. This method involves selecting the tree to be felled, approaching the tree with the apparatus, severing the tree from its roots, chipping the tree utilizing a chipping apparatus, and finally blowing the tree chips to the stand or depositing them on the forest floor. A number of different apparatuses have been suggested for carrying out this method. In case a large tree (a tree with large trunk diameter and height) is to be felled, and the trunk is to be used as timber, the tree trunk is grappled, severed from its roots above the ground, and is delimbed up to a given height. The trunk is lifted above the machine and is tilted by means of support arms, then it is severed from the crown and finally transported to the collection site. Residual limbs and other parts of the crown are chipped in the chipper apparatus of the machine. This apparatus can be advantageously applied for required tasks of forestry, that is, for controlling stands, singling out and removing unwanted trees while preserving others, but the apparatus is not capable of working in a continuous regime and therefore is unsuitable for the continuous harvesting of tree stands. Furthermore, the apparatus is complex and extremely costly.

For felling and chipping smaller trees the patent description DE 35 36 459 suggests a simpler adapter connectible to a tractor. The adapter comprises cutting blades and a chipping apparatus, with the cutting blades being foldable upwards about a horizontal axis. A transport means is connected to the input of the chipping apparatus, with a chips discharge chute comprising a discharge cone being connected to the output. The cutting blades of this adapter are only suitable for felling trees or saplings with small-diameter trunks. Also, the felled tree gets tilted while it is being conveyed to the chipping apparatus, and therefore it is impossible to utilize the adapter for continuous operation.

Patent description DE 196 10 452 discloses an apparatus for cutting down and chopping standing crops, for instance young trees. The apparatus comprises a pair of counter-rotating rotors comprising cutting discs and upward tapering screw blades. The edge of the screw blades is sharpened to vertically draw in and chop stems/trunks that are supported by other means. The apparatus has the disadvantage that the chopping edges of the screw blades are prone to be damaged easily and frequently, which increases maintenance costs and reduces productivity. It is also disadvantageous that cutting down and chopping of lower-diameter stems/trunks is not reliable. The stems/trunks easily lie down, after which chopping becomes cumbersome and uneven. A further disadvantage is that the rotor pair cannot adapt to changes in tree trunk diameter.

The aim of our invention is to improve existing feller-chippers and provide a reliable apparatus that can be operated economically. Our objective included that the trees severed from their roots should be securely engaged and guided during the whole course of the operation, keeping the trees in upright position until the process is finished. A further objective set before the inventive machine was that the hauling-in and feeding device should be capable of adapting to changes in tree trunk diameter, and that it should also be capable of producing uniformly sized wood chips.

The inventive objective is achieved by providing a tree feller-chipper introduced in the first paragraphs of this document, with the hauling-in and feeding unit consisting of a hauling-in portion adapted for keeping the trees in upright position and conveying them to the chipper unit, and a feeding portion adapted for thrusting the trees into the chipper unit, with the hauling-in portion extending over the chipper housing of the chipper unit, and with said chipper housing comprising an opening. The hauling-in portion consists of two parallel-axis conical screws, with the axes thereof being arranged at an acute angle with respect to the direction of translation, with the first conical screw being fixedly arranged, the outer diameter of the conical envelope surface thereof decreasing in the direction of the chipper unit, while the diameter of the conical core thereof increasing in the same direction, and with the second conical screw being displaceable against a spring, with the outer diameter of the conical envelope surface and the diameter of the conical core thereof increasing in the direction of the chipper unit. The feeding portion is implemented as two counter-rotating, parallel-axis feed rolls comprising claws or grapple blades.

The feller-chipper is mounted on a frame structure that can be implemented as a mobile structure or as connectible to a tractor. Operating units of the machine are attached to the frame structure in a manner conventionally applied in machine construction. Support beams carrying the guiding elements are attached to the frame structure in such a way that enough room is left between the guiding elements for enclosing the tree trunks as the machine moves forward. The support beams may have a fixed-height arrangement, but they may also be adjustable. In the latter case the guiding elements are attached such that the height and the direction (relative to the direction of travel) thereof can be adjusted.

In a preferred embodiment of the invention the guiding elements are attached to the support beams. According to the invention the guiding elements are implemented as guide screws, with the axles thereof being journalled in the support beam. Axles of the guide screws may be arranged parallel with each other and with the direction of travel. In certain cases it may be advantageous if the axles of the guide screws are set at a non-zero angle with respect to each other and/or the direction of travel. It may also be of advantage if this angle is adjustable. To provide for the adjustability of the relative angle of the guide screws, the axle of one of the guide screws may be attached to the support beam through an adjustment unit known per se.

The guide screws may be made of strip metal wound around a central core. It may be advantageous if the guide screws are implemented as bent metal or plastic rods or pipes that are attached (for instance via spacer elements) to the axles. The spatial (envelope) surface of the guide screw may also be formed by bending the rod or pipe on a conical surface. Guide screws may be driven by electric or hydraulic drive means. According to a preferred embodiment the axles of the guide screws are driven by hydraulic motors.

The cutting unit of the inventive feller-chipper is implemented as saw discs attached to the frame structure. Axles of the counter-rotating saw discs are journalled in the frame structure and are set substantially perpendicular to the direction of travel. The frame structure may have a fixed configuration, in which case the saw discs are not adjustable in a direction perpendicular to the direction of translation, hi a preferred embodiment the axles of the saw discs are journalled in a portion of the frame structure that is rotatable about a binge. Such a configuration of the frame structure provides that the ground clearance of the saw discs is adjustable and therefore the trees can be severed from their roots at variable height to suit different conditions. Saw discs may be driven by electric or hydraulic means. In a preferred embodiment the saw discs are driven by hydraulic motors. According to a further preferred embodiment, axles of the saw discs and hydraulic motors mounted thereon are surrounded by a protection frame. The protection frame protects the mechanism from colliding with or rubbing against tree trunks, and helps guide the trees into the hauling-in and feeding unit.

Between the saw discs and the chipper unit a hauling-in and feeding unit is attached to the frame structure of the feller-chipper, with the forward end thereof extending over the saw discs, and the rear end extending over the chipper housing. The hauling-in and feeding unit preferably consists of two portions: a hauling-in portion and a feeding portion. The hauling-in portion is constituted by two counter-rotating, parallel-axis conical screws, one of which being fixedly arranged, and the other being displaceable. The screws may be implemented as single-thread screws of identical pitch, but a configuration where one of the screws has double threads may also be advantageous. Screws of the hauling-in portion may be of the same length, but according to another advantageous configuration one of the screws may also be made shorter. This arrangement is especially suitable for guiding and passing the felled trees into the hauling-in and feeding unit.

The feeding portion is connected to the hauling-in portion. The feeding portion consists of two counter-rotating rolls which grapple tree trunks passed between them and thrust them into the chipper housing. Rotating rolls of the feeding unit have teeth or protruding claws for the more effective grappling of tree trunks. The feed rolls may have protruding grapple plates seated in the surface of the rolls, set parallel with the longitudinal axis thereof. Screws and feed rolls of the hauling-in portion are preferably driven by hydraulic motors.

The chipper unit is attached to the frame structure rearwards from the hauling-in and feeding unit. The configuration of the chipper unit is known per se, disclosed for instance in Hungarian patent HU 185122. The chipper unit has a preferably cylindrical volute housing comprising openings for introducing tree trunks and for discharging wood chips. The inlet opening disposed under the feed rolls is adapted for introducing the trees arriving in upright position into the chipper housing. A chipper disc comprising rotary knives is disposed inside the chipper housing. Trees are chipped by the rotary knives and the stationary knife, the latter being fixedly disposed inside the chipper housing. A discharge chute is connected to the chipper housing, preferably at the side opposite to the feed rolls. The discharge chute is connected to the chipper housing in a preferably tangential configuration. This arrangement fosters the ejection of wood chips from the chipper unit. Ejector paddles may also be added to promote the discharging of chips. Chips may be transferred from the chipper unit to a transport unit for transporting the product off the operation site. The chipper disc is rotated preferably by a hydraulic motor.

Details of the invention will be described in the following referring to the attached drawings, where

Fig. 1 shows the schematic top plan view of the inventive tree feller-chipper, Fig. 2 shows the schematic side elevation view of the tree feller-chipper shown in Fig. I₅ with

Fig. 3 showing the axonometric view of an embodiment of the tree feller- chipper according to the invention, while Fig. 4 shows the front view of the tree feller-chipper of Fig. 3 not showing the frame structure.

The schematic view of the inventive machine is shown in Fig. 1 and Fig. 2. The apparatus comprises a guiding element containing guide screws 6 and a cutting unit implemented as saw discs 9 coacting with the guiding element, with the guiding element being mounted on a frame structure (not shown in the figure). The guide screws 6 are rotatably arranged, with a pitch chosen such that the conveyance speed of the guide screws 6 equals the translation speed of the feller-chipper, which provides that the trees 20 are processed in upright position. The height of the saw discs 9 is adjustable with respect to ground conditions and other characteristics of the plantation to be harvested. A hauling-in and feeding unit is disposed rearwards from the saw discs 9, above the cutting unit. The hauling-in and feeding unit has a hauling-in portion and a feeding portion. The hauling-in portion is implemented as two conical screws 11, 12. The first, single-thread conical screw 12 is fixedly arranged, with the outer diameter of the conical envelope surface thereof decreasing, and the diameter of its conical core thereof increasing in the direction of the chipper unit. Due to this configuration the outer diameter of the screw blade decreases and the inner diameter thereof increases in the direction of the chipper unit.

The outer diameter of the conical envelope surface and the diameter of the conical core of the second conical screw 11 (being displaceable against a spring) increases in the direction of the chipper unit, and thus the screw blade of the conical screw 11 has constant height.

The two conical screws 11, 12 have identical pitch but the first, fixedly arranged conical screw 12 has single thread, whereas the second conical screw 11 has double threads. Such a configuration has the advantage of the screws firmly engaging effectively guiding the trees 20. The second conical screw 11 is displaceable against a spring, and thus it is pressed against the different-diameter tree trunks and thereby compensates for differences.

The axes of the conical screws 11, 12 are set at an acute angle α with respect to the direction of translation. The angle between the axes of conical screws 11, 12 and the direction of translation, as well as the pitch of the screws are chosen to provide that the trees 20 are kept in their natural, upright position during the cutting, drawing-in and chipping operation. The direction of travel is indicated by an arrow in Fig. 2.

The conical screws 11, 12 are integrated with feed rolls 13. The trees 20, guided by the guide screws 6, cut down by the saw discs 9 and passed between the conical screws 11, 12, are grappled and trusted into the chipper unit by the feed rolls 13. The feed rolls 13 comprise grapple blades 14. Feed rolls 13 have a configuration known per se. Such feed rolls are disclosed for instance in the document DE 35 36 459.

The chipper housing 15 of the chipper unit has a closed volute shape, and includes a chipper disc comprising rotary knives 16. hi Fig. 1 the chipper housing 15 is shown without its cover. A stationary knife 17 is fixedly disposed inside the chipper housing 15, with ejector paddles 19 being also disposed therein. An inlet opening is disposed on the top of the chipper housing 15, below the feed rolls 13. A discharge chute 18 is tangentially connected to the chipper housing 15 opposite the inlet opening. Arranging the discharge chute 18 this way fosters the discharging of wood chips from the chipper unit. The discharge of chips is also aided by ejector paddles 18. The rotational speed of the chipper disc has to be established in correspondence with the speed of the feed rolls 13 to provide the desired chips size.

Fig. 3 and Fig. 4 show an embodiment of the inventive feller-chipper that is adapted for being connected to a tractor. The apparatus is mounted on a frame structure 1. The frame structure 1, which also contains the wheel axle bearings, is connected to the tractor by means of an asymmetrically extending forward boom. Two support beams 2 adapted for carrying the guide screws 6 are fixedly attached to the frame structure 1. The support beam 2 has a stationary portion 3 and a moving portion 4 mounted on the stationary portion 3 in a manner that it is displaceable in a vertical direction. The moving portion 4 is applied for adjusting the vertical position of the guide screws 6 in order to suit the height of the plantation trees to be harvested. A boom 5 is attached to the moving portion 4 such that said boom 5 can be displaced along a line parallel with the translation direction of the machine. The moving portion 4 and the boom 5 are hingedly connected, and thus the axles 7 of the guide screws 6 can be turned (the angle between the axles and the direction of translation can be adjusted). To set the axles 7 in the desired direction a spring (not shown in the drawing) is disposed between the moving portion 4 and the frame structure 1. The axles 7 of the guide screws 6 are journalled in the boom 5.

As it can be clearly seen in Fig. 4, guide screws 6 are implemented as rods bent on a conical surface. The attachment of the guide screws 6 to their axles 7 is not shown in the drawings, and can be carried out utilizing support elements or fixing rods in a manner that is obvious for those skilled in the art. Inside the axles 7 of the guide screws 6 hydraulic motors 8 are disposed for rotating the guide screws 6. The guide screws 6 are attached to the frame structure 1 such that they enclose the trunks of trees 20 and keep them in their natural, upright position as the machine moves forward. Such a configuration of the guiding elements can be known from our previously produced constructions.

The axles of the saw discs 9 are also attached to the frame structure 1, with said saw discs 9 being disposed rearwards from and below the guide screws 6. Because the axles of the saw discs 9 are journalled in a hingedly rotatable element of the frame structure 1, the vertical position (and thus the ground clearance) of the discs is adjustable. The saw discs 9 are directly driven by hydraulic motors 8. A protection frame 10 surrounds the drive axles and motors of the saw discs 9. Beside its safety function, the protection frame 10 also plays a role in guiding and orienting the trees 20.

Trees 20 are guided by the guide screws 6 to the saw discs 9, and, after being severed from their roots, tree trunks are passed to the hauling-in and feeding unit. The conical screws 11, 12 of the hauling-in portion are attached to the frame structure such that there is an acute angle α between their axes and the direction of travel, with free ends of the conical screws 11, 12 extending above the saw discs 9. For the sake of better visibility, the frame structure 1 is not shown in its entirety in Fig. 4. The first conical screw 11 has a single-thread configuration, while the second conical screw 12 is implemented as a double- thread screw. Screws of the hauling-in portion have different length, which helps the introduction of trees 20 therein. The outer diameter of the screw blade of the single-thread conical screw 12 decreases and the inner diameter thereof increases in the direction of the chipper unit. The second, double-thread conical screw 11 has a uniform-height blade and is arranged such that it is displaceable against a spring. This manner of attachment and biasing is obvious and well known for those skilled in the art, and thus it is not illustrated in detail in the drawings.

Feed rolls 13 comprising grapple blades 14 are connected to the conical screws 11, 12. Similarly to the above described moving parts, elements of the hauling-in and feeding unit are driven by hydraulic motors.

A chipper unit is also mounted on the frame structure 1. As it can be clearly seen in Figs. 3 and 4, the chipper housing 15 of the chipper unit has a volute shaped configuration, and is mounted on the frame structure 1 such that the front plate thereof is substantially parallel with the axes of conical screws 11, 12. An inlet opening is disposed on the front plate of the chipper housing 15 under the feed rolls for introducing the trees arriving in upright position into the chipper housing 15. A discharge chute 18 is tangentially connected to the chipper housing 15, preferably at the side opposite to the feed rolls 13. The configuration of the chipper unit is known per se, and is shown in Fig. 1. A chipper disc comprising rotary knives 16 is disposed inside the chipper housing 15. The tree 20 introduced by means of feed rolls 13 is chipped by the rotary knives 16 and by the stationary knife 17 fixedly disposed inside the chipper housing. Discharging of wood chips is fostered by discharge paddles 19. Chips may be transferred from the chipper unit to a transport unit for transporting the product off the operation site. The chipper disc is rotated by a hydraulic motor 8.

Example

The inventive feller-chipper was applied for harvesting a poplar plantation planted for energy purposes. The energy plantation was 3 years old, with tree diameters ranging from 8 to 10 cm, and tree heights reaching up to 6-8 metres.

The inventive feller-chipper was coupled to a tractor and passed between the rows of the plantation with a speed of 3-4 km/h. Guide screws 6 were rotated with an rpm of 160/min, providing that the conveyance speed of the screws was substantially equal to the translation speed of the machine.

The speed of the saw discs 9 was set to a value of 1000/min. The ground clearance of the saw discs 9 was adjusted such that stumps of about 10 cm in height would be left.

Harvesting of the plantation was carried out in a single operation with the above described parameters, with the trees 20 remaining in upright position during the whole process. With the application of the inventive feller-chipper not only the tree trunks but limbs and foliage were chipped in their entirety. Chips were transferred to a transport apparatus and carried off the site.

List of reference numerals frame structure support beam stationary portion moving portion boom

6 guide screw

7 axle

8 hydraulic motor

9 saw disc

10 protection frame

11 conical screw

12 conical screw

13 feed roll

14 grapple blade

15 chipper housing

16 rotary knife

17 stationary knife

18 discharge chute

19 ejector paddle

20 tree

α acute angle

Claims

1. Tree feller-chipper for harvesting forests, primarily planted forests and particularly energy plantations, comprising a mobile frame structure (1) or a frame structure (1) mounted on a tractor, a guiding element attached to the frame structure (1), where the guiding element is implemented as two counter-rotating guide screws (6) that engage the trees (6) at a height proximate to the centre of gravity thereof, with the axles (7) of the guide screws (6) being connected to a support beam (2) attached to the frame structure (1), the machine further comprising a cutting unit coacting with the guiding element, said cutting unit being implemented as two counter-rotating saw discs (9) attached to the frame structure (1) rearwards from the guiding element, and further comprising a hauling-in and feeding unit adapted for conveying the trees from the cutting unit to the chipper unit, where a chipper disc having rotary knives (16) being disposed inside the chipper housing (15) of the chipper unit, with a stationary knife (17) being also disposed in the chipper housing (15), and with the chipper housing (15) comprising an inlet opening facing the feeding unit, and further comprising a tangentially attached discharge chute (18) connected to the chipper disc,

characterised by that

the hauling-in and feeding unit consists of a hauling-in portion extending over the saw discs (9), the hauling-in portion being adapted for keeping the trees (20) in upright position and conveying them to the chipper unit, and a feeding portion extending over the chipper housing (15) of the chipper unit, with the chipper housing (15) comprising an opening, and the feeding portion being adapted for thrusting the trees (20) into the chipper unit, where the hauling-in portion consists of two parallel-axis conical screws (11, 12), with the axes thereof being arranged at an acute angle (α) with respect to the direction of translation, with the first conical screw (12) being fixedly arranged, the outer diameter of the conical envelope surface thereof decreasing in the direction of the chipper unit, while the diameter of the conical core thereof increasing in the same direction, and with the second conical screw (11) being displaceable against a spring, with the outer diameter of the conical envelope surface and the diameter of the conical core thereof increasing in the direction of the chipper unit, and with the feeding portion being constituted by two counter-rotating, parallel-axis feed rolls (13) comprising claws or grapple blades.

2. The tree feller-chipper according to Claim 1, characterised by that the guide screws (6) are attached to the support breams (2) such that the height and the direction relative to the direction of translation of the guide screws (6) can be adjusted.

3. The tree feller-chipper according to Claim 2, characterised by that the axles (7) of the guide screws (6) are set parallel with the translation direction.

4. The tree feller-chipper according to Claim 2, characterised by that the axles (7) of the guide screws (6) are set at a non-zero angle with respect to each other and/or the translation direction.

5. The tree feller-chipper according to Claim 1, characterised by that the guide screws (6) are implemented as metal rods or pipes bent on a cylindrical or conical surface.

6. Tree feller-chipper according to Claim 1, characterised by that the first, fixedly arranged conical screw (12) thereof has a single thread, with the second, displaceable conical screw (11) having double threads.

7. The tree feller-chipper according to Claim 1, characterised by that the guide screws (6), the saw discs (9), the conical screws (11, 12), the feed rolls (13) and the chipper disc are driven by hydraulic motors (8).