WO1997042803A1

WO1997042803A1 - Scarifier for forest rejuvenation purposes

Info

Publication number: WO1997042803A1
Application number: PCT/SE1997/000751
Authority: WO
Inventors: Sture Hall
Original assignee: Mickhall Ab
Priority date: 1996-05-15
Filing date: 1997-05-06
Publication date: 1997-11-20
Also published as: AU2918597A; SE9601873L; SE9601873D0; SE506583C2

Abstract

A scarifier intended for forest rejuvenation purposes comprises a frame (5) which supports at least one scarifying device and has means for coupling the unit to a traction vehicle (1). The scarifier device comprises a brush (6) the purpose of which is to free the ground from the plant surface layer or organic debris without digging itself down in the ground. The coupling means includes a universal hinge (9) located at a front end of the frame (5) which hinge permits pivoting the unit relative to the traction vehicle horizontally as well as vertically, as well as lifting mechanism (11) by means of which the unit may, when necessary, be lifted up from a floating state on the ground. The frame has a second universal hinge (9A) at the rear end thereof, to which one or more other brush-equipped units (3) and/or a subsoil-consolidation device (4) may, when necessary, be coupled.

Description

SCARIFIER FOR FOREST REJUVENATION PURPOSES

Technical Field of the Invent-.inn

This invention relates to a scarifier intended for for- est rejuvenation purposes, in particular mechanized seed-sow¬ ing, comprising a frame which supports at least one scarifying device and has means for coupling the unit to a traction vehi¬ cle, more precisely in the form of, on one hand, a universal hinge located at a front end of the frame which hinge permits pivoting of the unit horizontally as well as vertically, and, on the other hand, a lifting mechanism by means of which the unit may, when necessary, be lifted up from a floating state on the ground.

Background of the Invention

For forest rejuvenation, three different, alternative main methods are applied, viz. natural seed-sowing from remain¬ ing, selected seed trees, manual or mechanized sapling planting as well as more or less mechanized seed planting. The natural rejuvenation from remaining seed trees is unreliable and often gives a bad and uneven regeneration. Sapling planting has the disadvantage that the growing trees often get a poor quality as a consequence of the fact that the root system of the sapling has not been developed at the site from the beginning. Another disadvantage is that the tender saplings planted in geometri¬ cally conformal straight rows constitute an attractive and eas¬ ily found feed for e.g. elks or moose. For these and other rea¬ sons, the development in forestry has lately been directed towards rejuvenation by mechanized seed-sowing. However, this development has not be followed by any adaptation of known scarifiers to the new forest rejuvenation technique. Thus, as exemplified in SE 9401038-6, very aggressive scarifiers of the kind with operates with rotatable, tooth-equipped disk wheels, which are brought to dig themselves down more or less deep in the ground, are still used for seed-sowing machines. When such units are brought forward by a suitable traction vehicle, marked tracks or strings of soil material are left in the ground which in practice are badly suited for seed-sowing. Thus, the excavated and loosened soil material contains a high proportion ot meagre material, such as gravel, sand and stones. Furthermore, the loosened material tends, to dry up too quickly and also be put in motion in connection with rainy weather. This is inappropriate in connection with the fact that a sown seed is to be developed to a tender sapling.

In this connection, it may also be mentioned that tests have been made to plant seeds directly into uncultivated ground, viz. in the surface layer or organic debris of the ground. However, said tests have not been fortunate inasmuch as the germinability of this method has become very mediocre. An explanation thereof is that small animals and insects, such as snails, pine weevils and the like, which live in unmoved organic debris, quickly consume the sown seed.

Objec s and Features of the Invention

The present invention aims at obviating the above-men¬ tioned shortcomings of earlier known seed-sowing methods and at creating a scarifier especially suitable for seed-sowing which enables an effective forest rejuvenation. Thus, a primary object of the invention is to provide a scarifier which, on one hand, effectively and carefully removes the organic debris from the ground surface on which seed-sowing is to take place, and, on the other hand, leaves the nutritious humus layer of the ground without any serious mechanical encroachment. Further- more, the unit should be able to work in highly varying ground and terrain conditions. The exposure of the nutritious, super^¬ ficially positioned humus layer should then take place gently and without letting stones loose.

According to the invention, at least the primary object is attained by the features defined in the characterizing clause of claim 1. Preferred embodiments of the invention are furthermore defined in the dep^ dent claims.

Brief Description of the Annended Drawings In the drawings :

Fig 1 is a side view showing a traction vehicle as well as a number of scarifiers according to the invention con¬ nected thereto, Fig 2 is a planar view from above showing how three, laterally separated sets of scarifiers according to the invention may be connected to the traction vehicle according to fig 1, Fig 3 is an enlarged side view showing a set of scarifiers illustrated in an up-lifted state,

Fig 4 is a corresponding side view showing the units in an active state abutting against the ground,

Fig 5 is a planar view showing an individual unit set in an enlarged state, and

Fig 6 is an enlarged detailed side view.

Detailed Description of a Preferred Fmhndiment nf the Invention In fig 1, reference numeral 1 designates a traction vehicle in the form of a forwarder to which several, more pre¬ cisely three sets of scarifiers 2, 3 are connected. The front unit 2 is connected to the traction vehicle in each individual unit set, while a subsoil-consolidation device designated 4 is connected to the rear unit 3. As may be seen in figures 3 to 6 , the individual scari¬ fiers 2 and 3 respectively comprise a frame 5 which carries a scarifier device, which, in accordance with the invention, con¬ sists of a brush 6. Said brush is rotatable and cylinder-shaped with individual bristles radially directed in relation to a substantially horizontal, geometric rotation axis 7. In prac¬ tice, the brush may be composed of a plurality of relatively thin rings of bristles dismountably arranged on a common axis . The width of the brush may be varied according to desires by choosing the number of bristle rings in a suitable way. The axis of the brush is mounted in a holder 8 , which in turn - at least in the front unit 2 - is pivotally movable relative to the carrying frame 5. In this way, the plane of the brush may be oblique in relation to the longitudinal axis of the frame, as clearly illustrated in fig 2. The frame 5 of the front unit 2 is, at the front there¬ of, connected to the traction vehicle 1 via a universal hinge or coupling, in its entirety designated 9, which comprises a vertical hinge axis 9' as well as a horizontal hinge axis 9" . Thus, said universal coupling permits pivoting the unit 2 relative to the traction vehicle horizontally as well as ver¬ tically. In the preferred example, shown in the drawings, the unit frame 5 is connected to an upright stand 10, which in turn is demountably connected, in an suitable way, to the chassis of the traction vehicle l. The stand 10 may, e.g., be connected to the chassis of the vehicle via pin joints (not shown) . A lif¬ ting mechanism in its entirety designated 11, which in the preferred illustrated embodiment thereof comprises two sepa¬ rated hydraulic cylinders 11 ' , 11", also extends between the stand 10 and the front scarifier. Each such hydraulic cylinder is, at the upper front end thereof, connected to the stand 10 via a hinge 12 which is located high on the stand. The indivi¬ dual cylinder is, at the opposite rear end thereof, connected to the carrying frame 5 via a universal hinge 13 which permits pivoting the hydraulic cylinder in relation to the frame in a horizontal as well as a vertical direction. As may be clearly seen in figures 2 and 5, the two hydraulic cylinders 11' , 11" of each lifting mechanism are oblique in relation to each other. More precisely, the cylinders converge in the direction backwards from the carrying stand 10.

A level-retaining element 14 abuttable against the ground co-operates with the carrying frame 5, which element, in the shown, preferred example, consists of an oblique and slide- likely movable plate located in front of the brush 6. Said slide plate 14 is dispiaceably movable and lockable in desired positions relative to a fix guide device 15 protruding down¬ wards from the bottom side of the frame. By displacing the slide plate 14 in relation to the guide device 15, the lower edge of the plate may be adjusted to a desired, variable level relative to the lower part of the brush 6 abutting against the ground. In other words, the abutting pressure of the brush against the ground may be varied. Thus, in a state when the lower edge of the slide plate is lowly adjusted in relation to the brush, it will work with a low pressure against the ground. Inversely, the brush will cultivate the ground aggressively in case the lower edge of the slide plate is adjusted at a high level relative to the bottom part of the brush. Although a slide plate of the described kind is preferred as a level- retaining element, it is perceivable per se to replace and/or supplement the same with one or more supporting wheels. Within the scope of the invention, it is also feasible to produce the relative possibility of motion between the level-retaining ele¬ ment and the brush by arranging the brush vertically movable at the same time as the level-retaining element is arranged in a fixed way (or alternatively, also movable) relative to the carrying frame.

In practice, the brush device 6 may be partly enclosed by a cap 16 composed of two side walls and a back piece. Each rear scarifier 3 is constructed in mainly the same way as the front unit 2, viz. said scarifier comprises a frame, a brush device as well as a level-retaining element. Further¬ more, said scarifier includes means for connection thereof to the front unit via a universal hinge 9A. An analogue universal hinge 9B at the rear end connects the unit 3 to the subsoil- consolidation device 4. Although the rear unit 3 is not con¬ nected to any hydraulic cylinders, there are means in the form of hinge fastenings 13 ' to connect the unit with such cylinders when necessary - when the unit is used as a front unit . The subsoil-consolidation device 4 comprises, apart from a frame 17, one or more wheels 18 which carry the frame and are connected to a corresponding number of seed-feeders 19 via transmissions 20, which have the purpose of guaranteeing an out-fed of seeds synchronised with the propulsion speed of the unit. Advantageously, the wheels 18 have, in a known way per se, radial projections which bring about small holes in the surface layer of the ground or the soil when the wheel crosses the same. By the fact that the frame 17 is articulatedly connected to the scarifier in front thereof and is only carried by the wheels 18, the whole weight of the device 4 will act against the ground via the wheels . This entails that the surface layer of the ground is effectively compressed at the same time as the projections of the wheels form distinct holes in the compressed surface layer of the ground. In fig 3, the hydraulic cylinders of the lifting mecha¬ nisms 11 are shown in an active state, in which they hold the scarifiers 2, 3 as well as the subsoil-consolidation device 4 in an up-lifted transport state. However, in fig 4, the hydrau¬ lic cylinders are non-active, i.e. no oil pressure is applied thereon. In this state, the scarifiers as well as the subsoil- consolidation device therebehind rest on the ground in a float¬ ing state in which they follow the traction vehicle in front thereof.

The Function and Advantages of the Tnven inn

In the preferred embodiment illustrated in figures 1 and 2 , three sets of trailing units are connected to the traction vehicle 1, each one of which comprises two scarifiers 2, 3 and a terminating subsoil-consolidation device 4. The brush device 6 in each front unit 2 is most suitably oblique relative to the direction of travel, while the rotation axis of the individual brush device 6 in each rear unit 3 is perpendicular to the direction of travel. The two brush devices of each trail unit are arranged to rotate in opposite directions of rotation. More precisely, each front brush device has the purpose of feeding away-swept surface material in the direction obliquely back¬ wards, while each rear brush device brings exposed soil mate¬ rial to be fed in the forward direction. Thus, each front brush device will remove the organic debris of the ground and care¬ fully expose underlying humus layer or soil as the traction vehicle is moved in the terrain. By the fact that the front brush device is oblique relative to the direction of travel, the removed surface layer material will be thrown to the side. The brush device of the rear scarifier 3, which in practice should be somewhat thinner than the width of the surface track which is produced by means of the front brush device, will loosen the exposed soil material and bring the material in a substantially ring-shaped motion path where the material is first thrown towards the slide plate in front thereof and then falls down in the space between the brush device and the back piece of the surrounding cap. In other words, loosened soil is returned to the first exposed track, more precisely in a string after the brush device. In conclusion said soil string is com- pressed by means of the wheel or wheels 18. The rotation of said wheels guarantees, via the transmissions 20, a synchro¬ nised out-feed of seeds from the seed-feeders 19. Said seeds are located superficially in the compressed soil string, more precisely to a great extent in the holes which have been pro¬ duced by means of the projections of the wheels.

The advantages of the invention are numerous. A primary advantage is that the brush device - contrary to aggressively working cultivation devices of the type tooth-equipped disk wheels - produces a very gentle exposure of the nutritious humus layer at the very top. Tests performed have shown that this guarantees a superior germinability compared to other seed-sowing methods. The fact that the soil, somewhat loosened by the rear brush device, is finally compressed by the rear subsoil consolidation device also contributes to this. Namely, in that the soil material is compressed, a capillary effect is obtained which under the first, very sensitive period of time for the growth of the seed to a viable sapling, contributes to keeping the surface soil damp. Another important effect of the relatively gentle treatment of the surface layer of the ground by the brush devices is that there is not formed any deep grooves with loose soil which at the first rain fall that comes along run the risk of being swept away from or being moved in the grooves. Thus, the soil material which is left after each scarifier according to the invention is kept reliably in place even if a heavy downpour would occur. This is a result of the fact that the root system of the plants in question, such as lingonberry and bilberry sprigs, are retained as a reinforce- ment of the soil mass.

Further Elucidation of Prior Art

In DK 155 901 a cultivation unit is previously disclosed which uses rotating brushes. However, this case concerns a weed killing unit which includes a plurality of brushes applied on a common axis which may be applied in furrows between sapling- covered soil strings. This unit does not at all include any coupling means of universal hinge type which, on one hand, admits coupling the unit to a traction vehicle in front thereof at the same time as a following, further unit may be coupled thereto. Feasible Modi ica ions of the Invention

The invention is not solely restricted to the embodiment described and shown in the drawings. The invention may thus also be applied even in the case when only one single scarifier is connected to the traction vehicle in front thereof. Thus, at good ground conditions, it may be fully sufficient to only brush away the superficial vegetation or organic debris. When this has been done, seed-sowing may be realised in another way than by means of a seed-feeder following immediately behind. For example, seed-sowing may take place on a later occasion, either in a manual or a mechanized way. It is even feasible to use the scarifier according to the invention also for sapling planting instead of seed-sowing.

Claims

1. A scarifier intended for forest rejuvenation purposes, in particular seed-sowing, comprising a frame (5) which supports at least one scarifying device and has means (9) for coupling the unit to a traction vehicle (1) , more precisely in the form of, on one hand, a universal hinge (9) located at a front end of the frame which hinge permits pivoting of the unit horizon¬ tally as well as vertically, and, on the other hand, a lifting mechanism (11) by means of which the unit may, when necessary, be lifted up from a floating state on the ground, c h a r a c - t e r i z e d in that the scarifier comprises a rotatable brush (6) , which is cylinder-shaped with individual bristles radially directed relative to a geometric axis (7) around which said brush is rotatable, the purpose of said brush being to free the ground from the plant surface layer or organic debris without digging itself down therein, and that the frame at the rear end thereof has a second universal hinge (9A) to which other brush- equipped units (3) and/or a subsoil-consolidation device (4) may - when necessary - be coupled.

2. Scarifier according to claim 1, c h a r a c t e r i z e d in that the brush (6) is rotatably mounted in a holder (8) which in turn is pivotably movable relative to the carrying frame (5) so as to enable oblique positioning of the brush in relation to the direction of travel of the traction vehicle.

3. Scarifier according to claim 1 or 2, c h a r a c t e¬ r i z e d in that the universal hinge (9) and the lifting mechanism (11) are permanently articulatedly connected to an upright stand (10) , which in turn may be dismountably connected to the traction vehicle.

4. Scarifier according to claim 3, c h a r a c t e r i z e d in that the lifting mechanism (11) comprises two separated hydrau¬ lic cylinders (11', 11") converging in the direction backwards from the stand (10) .

5. Scarifier according to any one of the preceding claims, c h a r a c t e r i z e d in that a level-retaining element (14) abuttable against the ground is connected to the carrying frame (5) and that said element and the brush (6) are verti- cally adjustably movable relative to each other so as to enable variation of the abutting pressure with which the brush culti¬ vates the ground.

6. Scarifier according to claim 5, c h a r a c t e r i z e d in that the level-retaining element consists of an oblique, slide¬ like plate (14) located in front of the brush (6) which plate is displaceably movable relative to a fix guide device (15) protruding downwards from the frame so as to locate the lower edge of the slide plate at a desired level relative to the brush.

7. Scarifier according to any one of the preceding claims, the subsoil-consolidation device (4) comprising one or more wheels (18) which are connected to a corresponding number of seed- feeders (19) via transmissions (20) , which guarantee an out- feed of seeds synchronised with the propulsion speed of the unit, c h a r a c t e r i z e d in that said wheels (18) have projections arranged to create holes or patterns in the plant surface layer which at the same time is compressed by the weight acting on the wheels.