WO1979000949A1

WO1979000949A1 - A machine for limbing trees and stems

Info

Publication number: WO1979000949A1
Application number: PCT/SE1979/000089
Authority: WO
Inventors: L Bruun
Original assignee: Bruun System Ab; L Bruun
Priority date: 1978-04-19
Filing date: 1979-04-11
Publication date: 1979-11-15
Also published as: FI791282A; IT1112211B; SE7804493L; FR2423144A1; ES479749A1; AU4613179A; IT7921936A0; NO791287L

Abstract

A machine for limbing trees and stems comprises a holding device (7) for holding the tree or stem during a limbing operation, said holding device being arranged on a stationary first frame structure (1, 2, 3); a limbing device (13) for limbing the tree or stem held by the holding device (7), said limbing device being arranged on a second frame structure (4, 5, 6) which is movable relative to the first frame structure (1, 2, 3); and a drive means (8) for moving the second frame structure (4, 5, 6) backwards and forwards relative to the first frame structure (1, 2, 3). For the purpose of reducing the amount of power required to operate the machine, the limbing device (13) is arranged, during the reciprocatory movement of the second frame structure (4, 5, 6) to be moved forwards and backwards along said second frame structure (4, 5, 6) by means of at least one chain or line (28) which passes over guide rollers (26, 27) arranged on the second frame structure (4, 5, 6), said chain or line being attached to the limbing device (13) and either to the first frame structure (1, 2, 3) or to a location which is fixed relative to said first frame structure in a manner such that the limbing device (13) moves twice as far as the second frame structure relative to the first frame structure during the reciprocatory movement of said second frame structure.

Description

A MACHINE FOR LIMBING TREES AND STEMS

The present invention relates to a machine for limbing trees or stems, and comprises a) a holding device for holding the tree or stem firmly during a limbing operation , said holding device being arranged on a stationary first frame structure ; b) a limbing device for limbing the tree or stem held by the holding device , said limbing device being arranged on a second frame structure which is movable relative to the first frame structure; and c) a drive means for moving the second frame structure reciprocatingly relative to the first frame structure.

One such known limbing machine is provided with a crane jib which is mounted on a vehicle and which comprises a plurality of mutually telescopic sections. Arranged on the innermost section of the jib is a holding device which is arranged to sieze and hold a tree dur¬ ing a limbing operation. At the outer end of the outermost section of the jib is arranged a shearing-type limbing tool, which is arranged in a manner such that it can alternatively be used as a gripping tool. When limbing by means of this machine, one end of the felled tree is gripped by the combined limbing and gripping tool on the outer end of the outermost section of the jib and is drawn forward to the holding device , by telescoping the jib , so that the end of the tree can be caught and held by means of the holding device. The tree is then limbed, by moving the limbing tool along the trunk of the tree , by extending the jib. In this type of limbing machine, the severed branches and knots are spread along the movement path of the limbing device, which is an advantage. This machine, however, has the disadvantage 'of being excessively high and long , and having a high tare weight, besides requiring a great deal of power to operate the same.

An object of the present invention is to provide α machine of -the aforedescribed kind which is not encumbered with the aforementioned disadvantages and which is of compact structure, low tare weight and requires but little power for its operation. '^■*■*■

This object is achieved by means of the machine according to the invention, in that the limbing device is arranged , during the reciprocating movement of the said second frame structure, to be moved reciprocatingly along said second frame structure by means of at least one chain or line which extends over guide rollers arranged on the second frame structure and which are mounted on the limbing device and either on the first frame structure or a location which is fixed relative said first frame structure, in a manner such that the limbing device moves twice as far as the second frame structure relative to the first frame structure during the reci¬ procating movement of said second frame structure.

In this way, it is also possible to limb trees and stems whose lengths considerably exceed the length of the first frame structure which, for example in the case of a vehicle-carried thinning machine, can correspond to the width of the vehicle.

So that the invention will be more readily understood and optional features thereof made apparent, an exemplary embodiment of the in- vention will now be described with reference to the schematic drawing in which Figure 1 is a plan view of those parts of the machine essen¬ tial for obtaining an understanding of the invention, Figure 2 is a front view of a limbing device , showing how this device is arranged in relation to the frame structures- of the machine, and ^'Figucce 3 illustrates how the limbing device is moved backwards and forwards. In the drawings , the reference 1 identifies a first or outer . frame structure which is of an elongate configuration and which in the illustrated embodiment comprises two mutually parallel U- beams 2 arid 3, said beams being arranged with the open sides there- of facing towards one another, as will best be seen from Figure 2. Arranged between the beams 2 and 3 of the first frame structure is a second or inner frame structure 4, which comprises two I-beams 5 and 6, said beams being connected together at the ends thereof by means of cross—members not shown.

Arranged at one end of the outer frame structure 1 is a holding device 7, this device being illustrated schematically in Figure 1 by means of a rectangle.

Centrally of the two beams 2 and 3 in the frame structure 1 , and beneath the holding device 7 is attached one end of a hydraulic piston-cylinder arrangement 8. The piston is arranged to be moved in either direction in the cylinder 8 in a manner known per se by means of a hydraulic fluid. The piston rod of the piston is connected to the outermost end (in Figure 1 the lowermost end) of the inner frame structure 4. Thus, the hydraulic piston-cylinder arrangement 8 forms a drive means by means of which the inner frame structure 4 can be moved backwards and forwards in the outer frame structure 1. The beams 5 and 6 of the inner frame structure are connected at their respective ends with outwardly directed trun¬ nions 9 on which rollers 10 are journalled , said rollers moving in the recesses in the beams 2 and 3 of the outer frame structure 1, as shown in Figure 2. Similar trumionsHare also mounted on the outer ends of the beams 2 and 3 of the frame structure l,said trunnions ^• ^"carrying rollers-12-which move in the adjacently, lying openings in the I-beαms 5 and 6 of the inner frame structure 4, as shown in Figure 1. It is assumed in this figure that the inner frame structure 4 is moved as far as possible out of the frame structure 1, and that the rollers 10 and 12 are thus located in those positions where th are nearest one another.

"- A limbing device generally referenced 13 is illustrated in schemat form in Figure 1, in the form of a rectangle , and is shown more in detail in Figure 2. This limbing device is mounted on a carria comprising a bottom plate 14 having mounted on the underside there¬ of two flanges or support means 15 which carry journals 16 on which rollers or pulleys 17 are journalled, said rollers or pulleys bein arranged to move in the mutually facing recesses in the I-beams 5 and 6.

The limbing device itself comprises a V-shaped or U-shaped member 18 which is mounted above the bottom plate 14. Pivotally mounted on the member 18 are two arms 19 and 20 each of which is pivotable about a respective pivotlocation 21 and 22. Each of the arms 19 and 20 carry a respective arcuate knife edge 23 and 24. The bottom of the V-shaped or U-shaped recess in the member 18 also has the form of a knife edge 25. The arms 19 and 20 can be rotated about s said respective pivot locations 21 and 22 by means of hydraulic devices not shown. In the position illustrated in Figure 2, the knife edges 23,24 and 25 embrace a substantially circular area. The tree to be limbed is placed in the machine with_, one end of the tree in the holding device 7, so that the tree trunk is located in the recess in member 18 on the limbing device. To enable the tree to be placed in this position, the arms 19 and 20 with knife edges 23 and 24 can be swung outwardly from the position shown in Figure 2. In this latter position, the knife edges 23, 24 and 25 completely encircle the trunk of the tree and the knife edges are so oriented that when the carriage is moved in a directio

O Pl αwαy from the holding device 7 , the said knife edges will sever the knots and branches projecting out from the trunk.

As beforementioned, the carriage with the limbing device can be moved relative to the inner frame structure 4, by moving the rol¬ lers 17 in the frame beams 5 and 6. The manner in which this move¬ ment of the limbing device is effected will now be described.

The cross members (not shown) which connect together the ends of the beams 5 and 6 of the inner frame structure 4 each carry two guide rollers or chain wheels. The guide rollers or chain wheels located at one end of the frame structure 4 are designated 26, while those located at the other end of said frame structure are designated 27. Extending over each pair of guide rollers 26,27 is a line or chain 28. The chains 28 are fixedly connected to the limbing device, namely on the underside of the bottom platre 14, and to the outer frame structure 1 or a location which is fixed relative to said frame structure. This is illustrated schematical¬ ly in Figure 3. In this Figure , the inner frame structure 4 is only indicated by a horizontal line , at the two ends of which the two chain wheels 26 and 27 are arranged. The chain 28 is fixed¬ ly connected at location 29 to the limbing device 13, which is also only indicated schematically in Figure 3. The underpart of the chain 29 is fixedly connected to the outer frame structure 1 at a location 30, or to a part of the machine which is fixed relative to said outer frame structure. When the inner frame structure 4, and the chain wheels 26 and 27 mounted thereto , is moved by the hydraulic device 8 (Figure 1) in one or the other direction relative to the outer frame structure 1, i.e. relative to the location 30, the chain 28 will move over the wheels 26 and 27 , whereby the location 29 and the limbing device 13 will

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.Λ Wi-o _.<. move in the same direction as the frame structure 4. It will readil be perceived that the limbing device 13 will move at twice the spee as the frame structure 4.

✓^ It is assumed that the attachment locations 29 and 30 of the chains 28 are so located that the inner frame structure 4 with the limbing device 13 can be moved to an inner position in which the limbing device 13 is located adjacent the holding tool 7, and also so that the inner frame structure can be moved to a position in which the limbing device 13 is located at a maximum distance from the holding tool 7. This maximum distance is determined by the length of stroke of the piston of the hydraulic arrangement 8. This hydraulic arrang ment is operated in a known manner, manually or automatically , by means of valves and hydraulic lines not shown. The movable knives 23 and 24 of the limbing device 13 are also operated by mean of hydraulic devices to which a working fluid is passed through pipe or hoses which suitably extend alongside the chains 28 between the locations 29 and 30 over one of the rollers 26 and 27, thereby preventing these pipes or hoses from being subjected to excess stresses as the limbing device is moved.

Claims

CLAIM :-

A machine for limbing trees or stems and comprising a holding device (7). for holding the tree or stem during the limbing opera¬ tion, said holding device being arranged on a stationary first frame structure (1,2,3); a limbing device (13) for limbing the tree or stem held by the holding device (7), said limbing de¬ vice being mounted on a second frame structure (4,5,6) which is movable relative to the first frame structure (1,2,3) ; and a drive means (8) for reciprocatingly moving the second frame structure (4,5,6) relative to the first frame structure (1,2,3), characterized in that the limbing device (13) is arranged to be moved,during the reciprocatory movement of the second frame structure (4,5,6) forwards and backwards along the second frame structure (4,5,6) by means of at least one-^*5chain or line (28) which ex¬ tends over guide rollers (26,27) arranged on the second frame structure (4,5,6) and which is attached to the limbing device (13) and either to the first frame structure (1,2,3) or a lo¬ cation (30) stationary relative to said first frame structure, in a manner such that the limbing device (13) moves twice as far as the second frame structure relative to said first frame structure during the reciprocatory movement of said second frame structure.