WO1999004105A1

WO1999004105A1 - Grasping member for excavator, excavator and use thereof various especially in sylviculture

Info

Publication number: WO1999004105A1
Application number: PCT/CH1998/000307
Authority: WO
Inventors: Robert Schnyder
Original assignee: Robert Schnyder
Priority date: 1997-07-15
Filing date: 1998-07-15
Publication date: 1999-01-28
Also published as: CH693222A5; AU8203798A

Abstract

The invention relates to a grasping member (1) for an excavator or analog having two grasping arms (5) which, in closed position, make an acute angle splitting wedge. Said grasping member is primarily designed to be used in afforestation works, to insert plants in the ground. The grasping element is used, with its grasping arms in closed position, firstly to dig a planting hole through introducing wedge in the desired ground, then said plant, for example a young fir, is grasped by means of grasping arms and inserted in said planting hole. To insert wedge-shaped grasping member, said member is preferably combined with a hydraulic hammer (2). The used excavator is especially a fully all-terrain walking excavator that is preferably provided with basket-type containers useful to transport and keep plants at disposal.

Description

DESCRIPTION

Grabs for an excavator, excavator, and uses thereof, especially in the forestry sector

TECHNICAL AREA

The present invention relates primarily to a gripper for an excavator or the like, with two gripping arms which can be moved between an open and a closed position and are attached to a fastening head. It further relates to uses of the gripper, in particular in the forestry sector, and finally also to an excavator specially designed in connection with the gripper and for the uses mentioned.

The increasing / deforestation of forests, especially rainforests in the tropical or subtropical area, is regarded as a major problem that has a lasting negative impact on the environment and the general climate. Efforts to limit deforestation have so far not been very effective. The successes achieved in the reforestation of deforested areas are also quite modest. So far, reforestation has not been able to keep pace with deforestation.

Experience shows that only a small part of the seedlings that are usually simply planted between the stumps of the cut down trees grows. Another part is eaten by animals or simply goes under between other, more rapidly developing soil plants. STATE OF THE ART

While very effective machines and processes are available for felling trees and their removal and further processing, a comparable effective device or process for reforestation is not yet known.

PRESENTATION OF THE INVENTION

The present invention has as its object to remedy this and solves this problem according to / claim 1, inter alia, by creating a gripper of the type mentioned for an excavator or the like, in which the gripping arms are designed so that they are in their closed position form an acute-angled riving knife.

Mounted on the arm of an excavator, the gripper according to the invention can advantageously be used for planting seedlings, with the gripper in the closed position of its gripping arms, in which they form a riving knife, first of all making a planting hole by driving the wedge into the desired planting ground and then with the same gripper without changing tools using the gripping arms of the seedling, e.g. a young fir, captured and inserted into the planting hole. This use is the subject of claim 19.

To effectively drive the wedge-shaped gripper into the planting ground, the gripper is preferably used in conjunction with a hydraulic hammer also mounted on the excavator arm, as is the subject of claim 21.

The planting method mentioned is particularly efficient when using an excavator, which, for example, for picking up in the swiveling range of its arm and thus of the gripper with suspension means in the form of basket-like containers or plate-like pallets, Transport and availability of the seedlings to be planted is provided. This is the subject of claims 24 and 25.

Since deforested forests, particularly in mountainous regions, are generally difficult to access and are rarely accessible, a so-called walking excavator is particularly suitable as an excavator.

Instead of an excavator, another machine or vehicle could of course also be used, where possible, e.g. a truck equipped with an excavator arm, whereby the seedlings to be planted can advantageously be carried on the loading surface and kept ready for planting. In the event of a conversion, only the hydraulic systems required for this must be available.

It is particularly preferred to place the young seedlings in the middle of or on top of them instead of between the stumps of the trees that have been picked up. This process, which i.a. Traditionally and successfully practiced by the American Indians, the main advantages are:

• The young seedling on the top of the tree stump is much better protected than between the tree stumps, especially if, as is the case in rainforests, they are quite large and tall. Protection also works against big game, which would otherwise eat up or trample down many young seedlings.

• The old stump provides the young seedling with sufficient nutrients for its development. Most of the seedlings planted in this way survive, grow and develop splendidly.

• On top of the stumps, the seedlings are not in competition with other soil plants and can therefore develop undisturbed. Despite these essential advantages, this planting method has so far been used only to a small extent, which is mainly due to the fact that the production of a suitable planting hole in the tree stumps, for example by hollowing it out, was extremely laborious. With the gripper according to the invention, however, a suitable planting hole can now be produced even in very large tree stumps simply by splitting the stumps while driving in the wedge-shaped gripper.

Using the gripper proposed by the invention, in particular in conjunction with a hydraulic hammer or vibrator, and a sufficiently strong excavator designed as described above, it is also possible to handle larger than previously customary seedlings, since practically all manual work is dispensed with and completely done by the machines becomes. The seedlings can already have a size of 100 - 150 cm. The chance that such seedlings will grow and prevail against pests and other influences is much greater than with the usual, usually no more than 50 cm large seedlings. The time for the regrowth of the forest is of course much less when using larger seedlings, which is another advantage.

In order to be able to be used in conjunction with a commercially available hydraulic hammer, the fastening head of the gripper according to the invention is preferably designed to be received in the chuck of such a hammer.

Furthermore, the two gripping arms are preferably attached to the fastening head in such a way that the acute angle which they form with one another in their closed position is adjustable. This offers the possibility, among other things, of being able to pull out a gripper clamped, for example, in a tree stump and rejuvenate its spreading position more easily. As a safeguard, particularly in the case of hammer operation or large tree stumps, additional grappling hook means with cutting hooks are expediently provided as anchoring. This ensures that the main unit or excavator is stable. This means that it can work with the boom fully extended without any stability problems. This means that the excavator does not have to be relocated so often during operation, but rather, due to its large radius of action, can perform a number of operations from one location.

The gripping hook means preferably comprise a pivotable and / or retractable and extendable arm. This arm can e.g. be designed with a telescopic cylinder. As a result of the mobility of the gripping hook means, they can be used not only for anchoring purposes during work, but also to support locomotion in the field. For example, a walking excavator can pull forward with such gripping hook means or repel them or use them as additional security.

The gripper can advantageously also be provided with means for introducing a liquid such as water between the gripper arms. This can e.g. be used for watering or watering the seedlings during planting.

The gripper arms of the gripper are preferably also designed such that, in their closed position, they form a container which is essentially closed downwards towards the wedge tip. In this case, in addition to the seedling, e.g. In addition, plant soil is gripped with the gripper and filled into the planting hole together with the seedling.

To make it easier to drive the wedge into the ground, the gripping arms can be tapered towards their tip or narrow. This is associated with a lower driving resistance and also a smaller volume or capacity of the gripper. For very hard surfaces, a sharp tip with a 4- or 8-edge design could even be used. Such a gripper is particularly suitable for the construction of large fence systems.

A gripper version, in which the gripper arms together have a conical shape and are mounted on a preferably hydraulic endless turntable, is particularly suitable for use on dry ground such as in desert regions. The two gripping arms are expediently interlocked by means of locking cams. For such applications, grippers are also expediently used which have a tip covered with hard cutting material such as diamond.

In order to enable the gripper according to the invention to be used in a variety of ways, its gripping arms can be exchanged in one embodiment, the conversion effort being quite low.

The application of the gripper according to the invention is of course not only limited to work in the forestry area. The gripper is also suitable for the construction of massive fence systems or for avalanche and torrent structures. best for. Here, too, holes must generally be made in the ground and subsequently a pile or the like must be inserted therein. With the gripper closed at the bottom and forming a container, the hole made with it could also be filled with liquid concrete.

Furthermore, the gripper can also be used to stabilize the floor, with the gripper in the closed position of its gripping arms, in which they form a riving knife, first of all making a receiving hole by driving the wedge into the ground and then using the gripping arms to convey piece goods such as stones, Rubble, tree trunk material, sandbags, etc. are introduced into the receiving hole, and are almost directly injected. Slope-prone slopes, bank embankments, dams or the like can be stabilized in this way. BRIEF EXPLANATION OF THE FIGURES

The invention will be explained in more detail below on the basis of exemplary embodiments in connection with the drawing. Show it:

1 shows the gripper according to the invention in a sectional view, the section along the section line A-A in the left part of FIG. 1 and the section along the section line B-B of FIG. 2 in the right part of FIG. 1;

2 shows the gripper in a side view of a gripping arm, certain elements which are not visible from the outside being shown in dashed lines on the inside of the gripping arms;

3 shows a further sectional view of the gripper, the gripping arms here being somewhat contracted compared to FIG. 1 while reducing the acute angle formed by them;

FIG. 4 shows a further side view of the gripper, however without the elements shown in broken lines in FIG. 2, in the position of the wedge relaxation;

5 shows the gripper with gripper arms opened to different degrees, including when a young fir is being cut out on the tree farm;

6 shows a stump with an inserted fir;

7 is a perspective view of a walking excavator equipped with a storage container when a young fir is planted in a stump; 8 is a perspective view of a walking excavator during the manufacture of an avalanche barrier on a mountain slope;

9 shows a gripper with gripping arms in the closed position when injecting rubble into the ground;

10 (a) in a schematic view from below and (b) in a schematic view from the side in the extended ramming position, an alternative embodiment variant of the gripping arms, which become narrower towards the tip thereof;

11 (a) in a schematic view from below and (b) in a schematic view from the side in the extended ramming position, another alternative embodiment variant of the gripping arms which taper to the tip;

12 (a) in a schematic view from below and (b) in a schematic view from the side in the extended ramming position, a further alternative embodiment variant of the gripping arms, which together form a cone and can be used together as a type of drill;

13 (a) is a schematic side view of a closed gripper with the gripping hook positioned, (b) a view of the gripping hook arrangement in the direction of the arrow B in FIG. 13 (a) and (c) a top view of the gripping hook, seen in the direction of the arrow C in Fig. 13 (a); and

14 shows a further mechanical realization of a gripper according to the invention with gripper arms of the embodiment variant according to FIG. 10. WAYS OF CARRYING OUT THE INVENTION

In the figures, 1 denotes a gripper, which is fastened in the chuck of a commercially available hydraulic hammer 2, which is only partially indicated. For this purpose, it has a suitable fastening mandrel 3 at its upper end. On a fastening head 4, two gripping arms 5 are fastened pivotably relative to one another, which are pointed towards their lower free end and form an acute-angled splitting wedge in their closed position. The acute angle which the two gripper arms 5 enclose in their closed position is denoted by α in FIG. 1. This angle is variable, which will be discussed in more detail below.

The two gripping arms 5 are provided with swivel bearings 6 on their upper part or end facing the fastening head 4. The pivot axis 7 of these pivot bearings 6 extends on both sides beyond these pivot bearings and is additionally supported in bearing shoes 8 there.

Neither the pivot bearing 6 nor the bearing shoes 8 are firmly connected to the mounting head 4. Rather, they are only on the underside and can even be slid a little along this. Fig. 3 shows the pivot bearing 6 and the bearing shoes 8 in a position shifted compared to FIG. 1.

With regard to this displacement, the underside of the mounting head 4 with sliding surfaces 9 for the bearing shoes 8 and

10 provided for the pivot bearing 7. There are also stop cams

11 provided for the bearing shoes 8. The sliding surfaces 9 and 10 are each aligned obliquely at about 45 with respect to the plane of symmetry 12 of the gripper. The fastening head 4 thereby also has an approximately wedge-shaped cross-section and has the tendency to press under pressure or impact from above between the two gripping arms 5 and to push their upper ends apart, at least until the bearing shoes 8 make contact with the Stop cam 11 come. This spread position is shown in Fig. 1.

The sliding surfaces 9 for the bearing shoes 8 and 10 for the pivot bearings 7 are arranged offset from one another at somewhat different heights, so that the gripping arms 5 are not laterally, ie perpendicular to the drawing plane in FIG. 1 or in the drawing plane opposite the fastening head 4 in FIG. 2 are movable.

The gripping arms 5 are held together with their bearing elements 6 - 8 on the fastening head 4 by means of a holding device 13 which comprises a holding cone 14 and a first hydraulic cylinder 15. The holding cone 14 is fixedly connected to the mounting head 4 and has a blind hole and a narrower through hole concentric with it. The blind bore receives a section of the cylindrical part of the hydraulic cylinder 15, whereas the piston of the hydraulic cylinder 15 is inserted through the through bore and anchored in the fastening head 4 with some play. At its lower end, the hydraulic cylinder 15 is connected to a yoke 16 to which two further hydraulic cylinders 17 are articulated together. The yoke 16 allows the hydraulic cylinders 17 to pivot upward, but prevents pivoting downward beyond their 180 position shown in FIG. 1. The piston rods of the hydraulic cylinders 17 are finally articulated on the gripper arms 5.

As can be seen, the gripping arms 5 can be tightened to the fastening head 4 with the hydraulic cylinder 15 by retracting its piston rod. By extending the piston rod, on the other hand, they can also be detached from it. Because of the play mentioned, with which the piston rod of the hydraulic cylinder 15 is anchored in the fastening head 4, the latter can even take place in an abrupt manner, an advantage which will be discussed below.

Towards its lower free end, the gripping arms 5 are bowl-shaped in that they are provided with side cheeks 18. Toothed ribs 19 are present on the inside. Its lower end is formed by teeth 20 made of hard metal, which interlock alternately. Finally, means such as spray nozzles 21 or the like are also provided for injecting a liquid, for example water, between the gripping arms 5.

As for the dimensioning of the gripper, a height of approx. 200 cm and a width between 50 cm and 100 cm are preferred. According to these dimensions, the gripper is intended to be mounted on the arm of an excavator or the like, preferably in conjunction with a hydraulic hammer such as that indicated in FIG. 1 and designated by 2.

In the following a preferred use of the gripper according to the invention e.g. for planting a fir seedling in a tree stump are described, it being assumed that the gripper according to the invention is mounted on the arm of a walking excavator in connection with a hydraulic hammer. For this purpose, the gripper with the excavator arm is initially placed with its wedge-shaped tip on the tree stump, which is designated by 22, with the gripper arms 5 closed. Then it is driven into the tree stump 22 under the blows of the hydraulic hammer acting from above on its fastening head 4, whereby the tree stump splits. The two hydraulic cylinders 17 are set so that the bearing shoes 8 are in their upper end position shown in FIG. 1 and bear against the stop cams 11. The acute angle α, which the gripping arms 5 form with one another, is maximum in this position and is preferably approximately 28 °.

To make it easier to pull the gripper back out of the tree stump 22 or the gap 23 in the tree stump, the first hydraulic cylinder 15 is freely moved and the further hydraulic cylinders 17 are retracted, as a result of which the two gripper arms 5 move toward one another with their upper ends. The swivel Bearing 6 and the bearing shoes 8 slide here along the sliding surfaces 9 and 10 of the fastening head 4 and, because of its wedge-shaped shape, press it upwards. The acute angle that the gripping arms 5 form with one another is thereby reduced. Fig. 3 shows the gripper 1 with such a reduced angle X of its gripping arms 5, which is a minimum of approximately 25 °. In this position, the gripper 1 can be pulled out of the gap or hole 23 produced by it without greater resistance.

If it is not possible to reduce the angle α solely by means of the further hydraulic cylinders 17, the fastening head 4 can also be pushed upwards with the first hydraulic cylinder 15. Because of the above-mentioned play with which the first hydraulic cylinder 15 is anchored in the fastening head 4, this can also be done in a pushing manner if necessary.

FIG. 5 shows how the gripper arms 5 of the gripper 1 can be pivoted against one another and opened by extending the further hydraulic cylinders 17 about their pivot bearings 6. The first hydraulic cylinder 15 is tightened again. 5, the two gripping arms 5 are shown in their widest spreading position. Two further spread positions are drawn with dashed lines. In the most closed spread position, a small fir 24 is held between the gripping arms 5 or straight out of a planting base 22 'e.g. cut out on a tree farm. Because of the preferred dimensions of the gripper 1 with a total height of approximately 200 cm, the fir 24 can itself easily have a height of 100-150 cm. In the second, further dashed spread position, the small fir 24 is in the planting hole 23 in e.g. applied in the afforestation area.

Immediately before or after planting, the seedling 24 can be watered using the means 21 and thus

FIG. 8 shows the same walking excavator 25 as is used for afforestation according to FIG. 7 during the manufacture of an avalanche barrier. Vertical piles 30 in the form of pieces of tree trunks have already been rammed into the ground. Furthermore, some crossbeams 31, again in the form of pieces of tree trunks, have been placed on the piles 30, which are used to hold back the sliding masses of earth, rubble and snow. As illustrated in FIG. 8, the use of the gripper 1 in an unchanged form is also possible for the manufacture of an avalanche barrier with corresponding ramming work in that the gripping arms 5 can also grasp tree trunks 32 or the like and place them safely.

FIG. 9 shows a gripper 1 with gripping arms 5 in the closed position when rubble 33 is injected into soil 34. The compaction of the soil formed adjacent to the receiving hole 35 is clearly visible. In addition to the rubble filling, these stabilize the soil or, for example, the embankment of a dam.

The gripping arms can be designed differently for the various uses of the gripper according to the invention, as are illustrated in a non-exhaustive manner from the above illustration, whereby they can advantageously be exchanged. 10 to 12 show some embodiment variants.

In the variant of FIG. 10 provided for cutting out larger quantities of trees, the gripping arms 5 ¹ become narrower towards their tip 40, the tip itself, however, being still blunt. Furthermore, the two gripping arms are also toothed at the tip with toothing sections 41 and 42.

The variant illustrated in FIG. 11 with gripping arms 5 ² , which taper to a point and form a right point 43, is particularly suitable for hard substrates and for the construction of large fence systems. Finally, FIG. 12 potential variant a usable also as a drill spe-, with gripping arms 5 ^3, which together form a cone and having at its tip a studded with diamond tip section 44. With such a gripper, work in dry and / or hard ground, desert areas, etc. should be made easier. For drilling, this embodiment must of course be mounted on a rotary drive on the excavator, although conventional hydraulic hammers regularly have such a drive. The rotatability of the gripper is illustrated by the arrow D. Since it is only possible to bail with completely closed and tightly fitting gripper arms, in this embodiment the adjustability of the angle α provided by the above-described embodiments, which the gripper shells form with one another, including the required special mounting of the swivel bearings for the gripper arms and on the hydraulic cylinder 15 may be waived. So that the gripping arms 5 ³ cannot move or shear against one another during drilling, they have teeth 45 in the form of cams in the closure region. On the outside, the Grei arms 5 ³ carry a protruding spiral structure 46, which has a repelling and compacting function. That is, it prevents jamming of the gripper 1 in the ground. In the example shown, the cone has an incline of approximately 15 to 25%.

It goes without saying that in order to drive in the gripper according to the invention by means of a hydraulic hammer attached to the arm of an excavator, the excavator must have a certain weight so that the hammer blows the gripper and not the excavator. This minimum weight, which the excavator must have, the higher the larger the construction stump or the harder the surface and the greater the driving resistance. In order to extend the area of application of the gripper according to the invention to lighter, smaller and therefore generally more off-road excavator types, the gripper can be equipped with a gripping hook 54 be provided, which is illustrated in the embodiment shown in Fig. 13 for an excavator, not shown. Insofar as parts are identical to those of the previously described exemplary embodiments, they are identified by the same reference symbols and will not be described again.

The gripper drive sits on a standard hitch, as is customary for excavators. This comprises a rotary plate 48 and a hydraulic hammer 2 (direction of impact in the direction of arrow A). The gripping arms 5 ³ are already in the gap position, ie they already extend into a tree stump 22.

The gripping hook 54 comprises a telescopic cylinder 50 which is pivotably mounted about a bearing axis 51 and which in the exemplary embodiment shown has approximately 20 tons of tensile and compressive force and can be retracted in the direction of arrow H from the extended position shown in FIG. 13 (a). Two cylinders 53 are arranged on both sides of the hydraulic hammer 2, and their one end is pivotably mounted about a bearing axis 55. Extending the two cylinders 53 results in an upward pivoting of the telescopic cylinder 50, as indicated by the arrow V. The swiveled-up position of the hydraulic cylinder 50 is indicated in the top left in FIG. 13a).

At its lower end, the hydraulic cylinder 50 carries a cutting hook 57 which, as shown in FIG. 13 (c), has sharp tips 56 and can be rammed into a tree stump according to FIGS. 13 (a) and (b). Rammed in this way, the gripping hook 54 serves as a counter anchor for the gripper 1 and can be braced against the latter with the telescopic cylinder 50. In this way it is possible to drive the gripper 1 into larger tree stumps even if the excavator used is too light in itself.

As can be easily seen, the gripping hook 54 can also be used as an anchor or as a walking foot when maneuvering the excavator.

me 5 ¹ are arranged. A change in the length of this hydraulic cylinder 60 causes at fixed pivoting jaws 63, the gripper 5 ¹ about the lower pivot joint jaw 65 open to the outside and can close again after.

LIST OF DESIGNATIONS

1 gripper

2 hydraulic hammers

3 fastening mandrel

4 fastening head

5 gripping arms

6 swivel bearings

7 swivel axis

8 camp shoes

9 sliding surfaces for camp shoes

10 sliding surfaces for swivel bearings

11 stop cams for 8

12 plane of symmetry

13 holding device

14 holding cone

15 first hydraulic cylinder

16 yokes

17 hydraulic cylinders

18 sidewalls

19 ribs

20 teeth

21 spray nozzles

22 tree stump

22 "planting base

23 Gap in the stump

23 "planting hole

24 fir

25 walking excavators

26 excavator arm

27 suspension means

28 auxiliary plant hole

30 posts

31 crossbars

32 tree trunk

33 rubble

34 soil

35 receiving hole top

Gear sections

top

Tip section

Gear cam

Spiral structure

Turntable

Telescopic cylinder

bearing axle

cylinder

Gripping hook

bearing axle

sharpen

Cutting hook

Hydraulic cylinder for gripper arms upper joint lower joint

Swivel jaw upper swivel jaw joint lower swivel jaw joint central hydraulic cylinder central joint

strut

Claims

PATENT / CLAIMS

1. Gripper (1) for an excavator (25) or the like, with two gripping arms (5) movable between an open and a closed position and attached to a fastening head (4), characterized in that the gripping arms (5) are designed in this way that they form an acute-angled riving knife in their closed position.

2. Gripper according to claim 1, characterized in that the fastening head (4) is designed to be received in the lining of a hydraulic hammer (2).

3. Gripper according to one of claims 1 or 2, characterized in that the two gripping arms (5) are attached to the fastening head (4) so that the acute angle

(α), which they form together in their closed position, is adjustable.

4. Gripper according to claim 3, characterized in that the fastening head (4) on its underside facing the gripping arms (5) and the gripping arms and / or bearing elements (6, 8) of the gripping arms on their upper part facing the fastening head with corresponding sliding surfaces

(9,10) are provided for the adjustability mentioned.

5. Gripper according to claim 4, characterized in that the sliding surfaces (9, 10) on the fastening head (4) are also wedge-shaped and engage between the gripping arms (5).

6. Gripper according to one of claims 4 or 5, characterized in that the gripping arms (5) via a first hydraulic cylinder (15) are connected to the fastening head (4) and by means of this cylinder to the fastening head can be attracted as well as pushed away or pushed away by it.

7. Gripper according to one of claims 1-6, characterized in that at least a second hydraulic cylinder, but preferably a pair of such cylinders (17) is / are provided for the adjustability of the gripping arms (5) between their open and their closed position.

8. Gripper according to claim 3, characterized in that between the mounting head (4 ¹ ) and gripping arms (5 ¹ ) elongated pivoting jaws (63) are arranged, which pivoting jaws

(63) on the one hand are movably connected to the fastening head (4 ¹ ) via an upper swivel jaw joint (64), and on the other hand are movably connected to the gripping arms (5 ¹ ) via a lower swivel jaw joint (65).

9. Gripper according to claim 8, characterized in that on the fastening head (4 ¹ ) laterally located at least two upper joints (61) are firmly attached, which upper joints (61) via hydraulic cylinders (60) with each of the two gripping arms (5 ¹ ) externally firmly attached lower joints (62), and which hydraulic rods (60) allow the gripping arms (5 ¹ ) to be opened around the lower swivel jaw joint (65) by changing their length accordingly.

10. Gripper according to any of claims 8 or 9, characterized in that at least one central, is mounted in the direction of the gripping arms (5 ¹⁾ downwardly facing hydraulic cylinders (66) on the mounting head (4 ¹⁾ below, in which the gripping arms (5 ¹ ) on the side facing a central joint (67), which central joint (67) is movably connected to the lower swivel jaw joints (65) by means of two struts (68), and by means of changing the length of these central hydraulic cylinders (66) the distance between the swivel jaw joints (65) can be changed, whereby the acute angle (α), which the gripping arms (5 ¹ ) form in the closed position with one another, is adjustable.

11. Gripper according to one of claims 1-10, characterized in that gripping hook means (54) with cutting hooks are provided as anchoring.

12. Gripper according to claim 11, characterized in that the gripping hook means (54) comprise a pivotable and / or retractable and extendable arm (50, 53).

13. Gripper according to one of claims 1-12, characterized in that means (21) are provided to introduce a liquid such as water between the gripping arms (5).

14. Gripper according to one of claims 1-13, characterized in that the gripping arms (5) in their closed position form a container which is essentially closed towards the wedge tip.

15. Gripper according to one of claims 1-14, characterized in that the gripping arms (5 ¹ , 5 ² ) are narrower towards their tip.

16. Gripper according to one of claims 1-15, characterized in that the gripping arms (5 ³ ) together have a conical shape.

17. Gripper according to one of claims 1-16, characterized in that the gripping arms (5 ³ ) have a tip studded with hard cutting material such as diamond.

18. Gripper according to one of claims 1-17, characterized in that the gripping arms (5) are interchangeable.

19. Use of the gripper (1) according to one of claims 1-18 for planting seedlings (24), with the gripper in the closed position of its gripper arms (5), in which they form a riving knife, first a planting hole (23) by driving the wedge into the desired planting base and then inserting the seedling into the planting hole with the gripper arms.

20. Use of the gripper (1) according to one of claims 1 -

18 for stabilizing the floor, with the gripper in the closed position of its gripping arms (5), in which they form a riving knife, first a receiving hole is made by driving the wedge into the floor and then piece goods are introduced into the receiving hole with the gripping arms.

21. Use of the gripper according to one of claims 1-18, characterized in that the gripper (1) is used in conjunction with a hydraulic hammer (3).

22. Use of the gripper according to one of claims 1-18, characterized in that the gripper (1) is used in conjunction with a vibrator.

23. Use of the gripper according to one of claims 1-18, characterized in that the gripper (1) is used in connection with a rotary drive.

24. Excavator, in particular walking excavator (25), on its arm

(26) a gripper (1) according to one of claims 1 - 18 is fastened and which excavator is provided in the swiveling range of its arm with suspension means (27) which serve to receive and hold objects (24) which are provided with the gripper is gripped and inserted into holes or gaps (23) previously made with the gripper.

25. Excavator according to claim 24, characterized in that the support means (27) are basket-like containers or plate-like.