BACKGROUND OF THE INVENTION Rigs for ground drilling of different sizes and for different purposes have been known for long. For example, when drilling fresh water wells and so called energy holes, i. e. holes intended for heat plants in rocks, it is necessary that the rigs are not too big, nor ungainly. In many cases the space is limited for passing through to assemble the rig for drilling, e. g. gardens. Normally such a rig is arranged with a drill mast which can be pivoted from a horizontal resting position to an upright working position, whereby the drill mast is positioned at the short end of the rig with the drilling head so to say directed rearwardly, i. e. having the mast positioned between the centre of the drill head and the short end of the rig.

Such rigs are either arranged with a storage space for storing drill pipes horizontally or totally lack a storage space, whereby the drill pipes are transported on an accompanying truck. In both cases the drill pipes need to be transported from the place of storage to the drill head, which today mainly is performed manually, by means of the operator carrying the drill pipes on the shoulder and thereafter raising the pipes to a vertical position for putting it in place underneath the drill head. Since these drill pipes can weigh up to 30 kilos it is obvious that it is a heavy and hard task to get the pipes into place for drilling. In order to achieve some kind of continuity during the drilling it requires two operators, one who handles the drilling and another one who transports the pipes.

The heavy and work intensive transport of the drill pipes is also necessary when the drilling has been completed in connection with removal of the drill pipes.

DESCRIPTION OF THE INVENTION This invention has as its object to minimise disadvantages in relation to the feeding of drill pipes to a drill rig for ground drilling and to achieve a more continuos operation.

According to the invention this is achieved by means of a device of a rig for ground drilling, which rig comprises a chassis and a drill mast which is arranged with a drill head, which drill mast is pivotally attached to the chassis about a mainly horizontal pivoting axis, mainly parallelly arranged in relation to one short end of the chassis, between a lying position and an upright position, whereby the drill head is positioned adjacent the short end of the chassis at the side of the drill mast, at least one storage space for storing drill pipes in a substantially horizontal position, and a feeding arrangement comprising a gripping device for transport of drill pipes between the storage space and the drill mast, i. e. from a substantially horizontal position to an upright position and vice versa, characterised in that the centre of the drill head in the working position of the drill mast, as well as the device for gripping, but not the drill mast, are arranged in one and the same substantially vertical plane and whereby the drill pipes, during feeding, are moved within said plane, without any need for making any circulating or twisting movements of the drill pipes in order to get them into position at the drill head With a device according to the invention many advantages are achieved. By arranging the rig with a storage space and by arranging the gripping device and the centre of the drill head in one vertical plane, a straight movement of the drill pipes from a lying position to upright position between the storage and the drill head can be performed by the feeding arrangement, providing a simple and reliable design which eliminates the need of performing circulating or twisting movements of the drill pipes to get them into place at the drill head.

Furthermore, the next drill pipe can be gripped by the gripping device of the feeding arrangement while the previous drill pipe is drilled into the ground. Thanks to the automatisation of the feeding of the drill pipes and that the drill pipes are stored in a storage space on the rig, the heavy manual work in handling the pipes is eliminated.

Moreover the design allows the rig to be compact such that a total width of less than 3 m easily can be achieved, which facilitates driving into a garden or similar.

According to further aspects according the invention the device is characterised by that: -the rig also comprises a holder capable of keeping a drill pipe in a substantially horizontal position for gripping thereof by the gripping devices, and a feeding device capable of feeding drill pipes from the storage to the holder, whereby the holder is arranged in said plane;

-the feeding arrangement is pivotally arranged about a pivoting axis which coincides with the pivoting axis of the drill mast; -a holder is arranged in close relationship to the storage space, that the feeding device comprises a hydraulic cylinder arranged between the rig and the storage space, that the storage is pivotally arranged about a substantially horizontal axis, substantially parallel with the drill pipes within the storage space and substantially parallel with said plane, whereby, during activation of said hydraulic cylinder, the storage space is pivoted and a drill pipe is moved to the holder; -said chassis comprises two long sides and two short ends, whereby the long sides of the chassis are arranged with a transmission belt; -a support leg is arranged in each corner of the chassis; -said support leg is movably attached in a horizontal direction and longitudinally adjustable in vertical direction; -the drill mast is made of one connected unit, such that the drill head is positioned at the side thereof.

These and further aspects and advantages of the invention will be apparent from the following detailed description of a preferred embodiment and from the appending claims.

BRIEF DESCRIPTION OF THE DRAWINGS In the following description of a preferred embodiment it will be referred to the annexed drawings, wherein: Fig. 1 shows a side view of a rig according to the invention; Fig. 2 shows a view from above of a rig according to Fig. 1; Fig. 3 shows a detailed view along the line E-III of Fig. 2; and Fig. 4 shows a sectional view of a preferred embodiment of the drill mast.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT The rig which is shown in the figures comprises a rectangular chassis 10 having two long sides 12 and two short ends 14. Transmission belts 16 are arranged at the long sides of the chassis. The chassis with transmission belts can preferably be assembled such that a total width of about 1.75 m is obtained. A power unit 18 for driving the rig by means of the transmission belts is arranged on the chassis. In each corner of the chassis there are arranged support legs 20, which support legs are movably attached in a horizontal direction, Fig. 2, as well as longitudinally adjustable in a vertical direction,

Fig. 1. A drill mast 22 with a drill head 24 is pivotally arranged to one of the short ends of the chassis, about a substantially horizontal axis 26, substantially parallel with one of the short ends of the chassis. A hydraulic cylinder 28 is arranged between the drill mast and the chassis in order to pivot the drill mast between a lying, resting, and transport position I, to an upright working position II. As is shown in Fig. 2 the drill mast 22 is arranged in such a manner on the chassis that the drill head 24 is positioned close to one of the short ends of the rig when the drill mast is upright, such that the drill head is positioned at the side of the drill mast, instead of being directed rearwardly as is known by prior art designs. The movable drill head 24, which according to prior art is slidably arranged at the drill mast 22, will therefor be moved upwards and downwards in a sliding plane 21 that is substantially parallel with the longitudinal direction of the chassis. In the upper part of the drill mast there is arranged a crane arm 30, or a jib. The drill tower 22 further comprises, also according to prior art, an adjustable part of the mast 23 which is arranged within the pivotally arranged part of the drill mast 22. The movable part of the mast 23 has as its object to support the drill tower throughmoving the adjustable part of the mast 23 into contact with the ground after having brought the tower 22 to an upright position.

A first storage space 32 for drill pipes 23 is arranged on the rig, Fig. 2 and 3, hereafter called the main storage space, which extends along one of the long sides of the rig. The main storage space comprises two arms 34 which are attached to the chassis, and which are sloping inwardly against the rig with a certain angle a in relation to the vertical plane. A holder 36 is pivotally arranged to the upper ends of the arms about substantially horizontal pivoting axis 38, which axis are substantially parallel with the long sides of rig. The holder is in the form of an upwardly open cradle with inner and outer lateral steerings 40,42 whereby the outer 42 is substantially vertical and the inner 40 mainly has the same angle as the arms. The lateral steerings are attached to lower beams 44. The drill pipes 33 are positioned horizontally on the lower beams and between the lateral steerings. A hydraulic cylinder 46 is arranged between the chassis and the retaining portion of the main storage space, capable of pivoting about its pivoting axis. At the upper end of the arms there is a holder 48.

A feeding arm 50 is pivotally attached to the chassis about a pivoting axis 26, which axis coincides with the pivoting axis of the drill mast. The feeding arm comprises a telescopically adjustable part 52 and a hydraulic cylinder 54 capable of prolonging and shortening the feeding arm, respectively. At the movable part of the feeding arm there are arranged two gripping devices 56 for gripping drill pipes. A hydraulic cylinder 58 is

arranged between the chassis and the feeding arm, provided for pivoting the arm between a substantially horizontal position and an upright position.

The centre C of the drill head 24, the holder 48 and the gripping device 56 of the feeding arm are arranged on the rig within substantially the same vertical plane P, which according to the shown embodiment is mainly parallel with the length axis of the rig.

The rig is preferably arranged with a second rigidly attached storage space 60 for drill pipes, positioned along the other long side of the rig, which storage space is in the form of two U-profiles which open up upwardly, within which U-profiles the drill pipes are positioned horizontally.

The function of the rig is as follows. The rig is driven to the place for drilling, whereafter the support legs 20 are moved and adjusted for stabilising the rig. Thereafter the drill tower 22 is moved from its resting position I to an upright position II by means of the hydraulic cylinder 28. The drill head 24 is moved up to the top of the mast awaiting a drill pipe. The feeding arm 50 is powered by means of its cylinder 58 to an upright position. The main storage 36 is activated whereby the retaining portion is pivoted by means of the hydraulic cylinder to a position IV, shown in Fig. 3. The pivoting of the retaining portion will make the drill pipes within the main storage roll towards the holder 48, whereby a drill pipe 33 is positioned therein. The retaining portion is thereafter pivoted in the other direction whereby the other drill pipes will roll back into the retaining portion, except for that pipe which now is positioned in the holder and in a position for being gripped. The feeding arm 50 is now again activated and pivoted downwardly against the drill pipe and grips it. Dependent on how the drill pipes are positioned in the storage space and the angle of the drill mast in its upright position it might be necessary to grip drill pipes at different positions along their extension. Thereby the length of the feeding arm is adjusted by means of the adjustable part 52 and its hydraulic cylinder 54.

The feeding arm is now pivoted upwardly whereby the drill pipe is moved from a horizontal position to an upright position. Thanks to having the drill head 24 so to say positioned at the side of the drill tower 22, i. e. close to the short end of the rig, and that the holder 48, the gripping device 56 and the centre C of drill head are arranged in the same vertical plane P, the positioned pipe will be moved in said plane and directly be positioned vertically in line with the centre of the drill head, without any need of further movement.

When the drill pipe is in position the rig starts to drill, and thereby the drill pipe 33 successively will be moved down into the ground, whereby at the same time the drill head 24, as is know per se, is moved downwardly along the sliding plane 21. At the same time the main storage space is reactivated in order to move a new drill pipe to the holder as is described above. The feeding arm moves downwardly and grips the next pipe. When the preceding pipe is drilled into the ground the drill head 24 is moved up to the top of the drill tower 22, the next drill pipe 33 is moved into position and is attached to the preceding pipe and drilling is continued. The above described cycle is continued until the desired drill depth is achieved. If more drill pipes should be required than the amount which is contained in the main storage, the crane arm 30 on the drill mast can be used to lift over drill pipes from the other storage space 60 to the main storage space 36.

The inverted procedure, i. e. removal of the drill pipes when the drilling is terminated, is similar. The drilled up drill pipe is gripped by the feeding arm and is moved down into the holder where it is released and moved into the storage space. It is possible to arrange some kind of activator (not shown), which so to say gives the drill pipe a push such that the pipe falls down into the storage space. At the same time, as the drill pipe is moved down to the storage, the drill head moves down and starts taking next drill pipe, where the procedure is repeated.

In Fig. 4 there is shown a cross section of a preferred drill mast 22, whereby merely the centre C of the drill head 24 is indicated. On the other hand the sliding plate 25 is shown in detail along which the drill head 24 is arranged. It is shown that the drill mast 22 comprises an inner rectangular part 22A, a triangular part 22B which is positioned at the opposite side in relation to the centre of the drill head C, two, at one side facing each other, U-beams 22C, 22D within which the drill mast is capable of being moved and two square pipes 22E, 22F which are arranged on each side of the rectangular part 22A in such a manner that they with one of the outer surfaces form a part of said sliding plate 21. The sliding plate 25 is at its surface that is facing the drill tower 22 arranged with sliding surfaces 25A, 25B made of appropriate material, preferably a durable polymer having low friction. These sliding plates 25A, 25 rest both on the rectangular part 22A and on the respective square pipe 22E, 22F. By means of L-formed arms 25C, 25D, which are arranged at the end of the plate 25, there are also sliding plates 25E, 25F which abut the back of the square pipe 22E, 22F such that the plate 25 is hindered from twisting in a horizontal plane. Furthermore there are rolls 25G, 25H arranged in the space between the end parts of the plate 25 and the L-formed arms 25C, 25D, which rolls 25G, 25H eliminate that the plate 25 can twist in a second plane. The design

therefor provides exact control of drill head 24 at the same time as undesired friction and pinching effects are eliminated.

A modification of the attachment of the feeding arm and its pivoting movement is shown by means of the dotted line V in Fig. 2, whereby the vertical plane within which the holder, the gripping device and the centre of the drill head are arranged, is not parallel with the longitudinal direction of the rig. The pivoting axis of the feeding arm may be somewhat angled, as is shown by it, in order to decrease the width of the rig by enabling movement of the storage space and the holder inwardly.

A further modification is that the feeding arm is moved along its pivoting axis, as is shown by the arrow VI in Fig. 2, during its feeding movement, i. e. the vertical plane within which the pipes are moved is arranged parallel with the longitudinal direction of the rig, but is moved perpendicularly in relation to the longitudinal direction during the feeding movement.

It is evident that the invention is not limited to the above described and to the embodiments shown in the figures but can be varied within the scope of the appended claims. The design of the storage space, the holder and the gripping device can be made in many other ways providing the same function.