When rock is drilled to a depth, for example in diamond drilling, it is important to be able to guide the drill in the desired direction. Drilling devices intended for this purpose are therefore provided with a guide mechanism or guide arrangement. These guide arrangements can be achieved, in the case of an outer sleeve which is non-rotating during drilling, with the inner rotary core barrel. The core barrel is the tube in which the drilling sample or product, etc. ends up and which is then raised to the ground surface. The core barrel is arranged in a connectable manner on the drilling tubes. The drilling tubes are joined to one another according to the prior art depending on the drilling depth and have the task of transmitting drilling pressure, rotation and drilling fluid for lubrication and cooling from a drilling machine to a cutter head, which cutter head produces a bored hole in the rock.

In order to be able to lock the outer sleeve arrangement against the wall of the rock hole, guide cages as they are known, having extensible supporting units, are used. A guide cage of this kind is described in the application accompanying this one.

Such a guide cage holds the non-rotating outer sleeve in a radial locked position at the same time as the guide cage permits the sleeve with the inner rotary core barrel being movable downwards in axial direction in a bored hole produced by the drilling device. The guide cage comprises a sleeve with recesses. In the recesses are arranged freely slidable supporting units. When the drilling fluid performs a pressure onto the supporting units from inside,

the supporting units are pressed outwardly against a wall of the bored hole and arrest the sleeve in a radial position. The friction of the supporting units against the wall of the bored hole is sufficient low being possible to overcome in axial direction by means of the pressure of the drilling tubes downwards. The sleeve of the guide cage has threaded portions, which are connectable with the outer sleeve, or also so called the outer sleeve device.

An interior movement limiting stopping sleeve is arranged central within the guide cage for preventing that the supporting units would fall into the guide cage when the core barrel is raised from the bored hole.

A guide arrangement for rock drills is described in EP 95 905 256.4.

According to this document, the guide cage is continually moved together with the core barrel as the drilling progresses. During the drilling, drilling fluid is fed under pressure from ground level through the interior of the drilling tubes down to the core barrel. According to EP 95 905 256.4, however, the mechanism which achieves the actual deflection of the core barrel and the outer sleeve in a desired bore hole direction is not described.

A variation is described in the said document to be attainable with the aid of a cam, which forces the outer sleeve towards the bore hole wall. The invention according to EP 95 905 256.4 works very satisfactorily. By making a sleeve device, which is on the outside during drilling, unable to rotate, is it possible to guide a drilling device comprising a rotary core barrel. It has been shown during practical tests, however, that the raising of the core barrel to the ground surface from the outer sleeve and the guide arrangement, which remain in the bore hole, takes up to 6-8 hours, depending on the bore hole depth. This is due to the fact that the drilling tubes have to be raised. A method currently used is wire-line drilling, as it is known, in which the core barrel can be raised to the ground surface without all the drilling tubes needing to be raised. These drill constructions are not, however, guidable.

In the case of a guidable drilling device, it is desirable that the drilling tubes should not need to be raised in connection with the emptying of the core barrel or if a new guidance adjustment needs to be made. It is desirable that the time spent raising the core barrel containing the drilling product or drilling sample, etc. should be able to be reduced, whilst at the same time a new guidance adjustment should be able to be made. When a core barrel is raised in this way, it is desirable if virtually all drilling equipment, including the guide arrangement, etc. apart from the core barrel, can be left in its position in the bore hole, which can extend up to four kilometres or more down into the rock. This in order to save time.

It is also desirable for the actual guide arrangement to be able to be left in its guiding position, so that no new alignment operation needs to take place.

It is likewise desirable that a means should be produced for adjusting the guide arrangement so that the drilling device can be guided in the desired direction.

A further requirement is that the diameter of the drilling device should advantageously be as small as possible. In this way, both the production costs and the operating costs are reduced. Likewise, the strength characteristics are able to be maintained as the drill diameter is reduced.

Likewise, the wall thickness of the drilling device can be kept to a minimum, so that a core barrel of greater diameter can be used.

A main object of the invention is to produce a coupling device for a rock drill, which coupling device is able to be used in guidable drilling devices and in which the coupling device allows the drilling tubes not having to be raised to the ground surface when the core barrel is emptied.

The object is further to allow rapid and economical access to the core barrel

during drilling in order to be able to use this core barrel to act upon the guide mechanism with the aid of, for example, different projections, which guide mechanism can be left in the bore hole together with the outer sleeve and all drilling tubes when the coupling device is in an uncoupled position.

Another object of the invention is to produce a connectable guide arrangement which is uncomplicated, reliable and easily adjustable on the basis of the exacting demands imposed in a rock drilling context.

The above-stated main object is achieved with a coupling device which has acquired the characteristics defined in Patent Claim 1. Further solutions to the object and characteristics of the invention are defined in the other patent claims.

With a coupling device of this kind, the possibility is obtained of rapidly being able to raise the core barrel without needing to raise the drilling tubes.

The invention is described in greater detail below with reference to the appended drawings, in which: Fig. 1 shows in diagrammatic representation a divided side view of a drilling device with a coupling device according to the invention, Fig. 2 shows in diagrammatic representation a coupling device in cross section according to the invention, Fig. 3 shows in diagrammatic representation a section A-A in Fig. 2 according to a first embodiment, Fig. 4 shows in diagrammatic representation a section A-A in Fig. 2 according to a second embodiment,

Fig. 5 shows in diagrammatic representation a splineway arranged on the coupling according to a third embodiment, Fig. 5a shows in diagrammatic representation a section through the splineway along the line A-A in Fig. 5, Fig. 6 shows in diagrammatic representation a guide cage described in an application accompanying the present application, Fig. 7 shows in diagrammatic representation a guide elbow which can be acted upon in a cost-effective manner by the coupling device according to the invention, Fig. 8 shows in diagrammatic representation a removable cutter head, and Fig. 8a shows in diagrammatic representation a core-lifter sleeve arranged on the core barrel.

In the following drawings 2,5,6,7,8 and 8a, the direction from a ground surface downwards is shown from left to right in the drawings. The drawings 2,5,6,7,8 and 8a show sections relevant to the invention, which drawings belong together in sequence and in the order followed by the drawing numbers. Fig. 8a shows, however, a section of the rock drill which, when the rock drill is in a coupled position, is partially hidden by the section shown in Fig. 8.

Fig. 1 shows an example of a rock drill 6 illustrated in divided sections with a coupling device 1 according to the invention in a side view. The ground surface is denoted by the reference notation m. A bored bore hole 9 is partly illustrated in the figure. This bore hole 9 has a bore hole wall 9a. A cutter head 31 is arranged, such that it can be uncoupled, on a lower end of the

rock drill 6 viewed in the direction of the bore hole 9 from the ground surface m. The word downwards, as used in this patent application, means precisely this direction. The word upwards means the opposite direction. An outer sleeve device 7, which is non-rotating during drilling, is arranged between the cutter head 31 and the coupling device 1. Inside this outer sleeve device 7, which is non-rotating during drilling, a core barrel 5, which rotates during drilling, is active. This core barrel 5 acts with a rotation force and compression force upon the cutter head 31. The core barrel 5 is acted upon, in turn, by a drive shaft (denoted by the reference notation 25 in Figs 2,5 and 6), which is connected to an inner, carrier housing 15 (see Fig.

2) belonging to the coupling device 1. The core barrel 5 is the tube in which the drilling sample or the product ends up in the course of the drilling. The drilling is therefore done at intervals and the core barrel 5 has from time to time to be raised to the ground surface m for emptying. In connection with this stage, a guide adjustment can also be made of an articulated section 30, that is in this application so-called a section 30 which laterally displaces the centre, which is arranged at a distance below the coupling device 1. The guide adjustment implies an adjustment of a drill direction for providing desired direction of the bored hole. A guide cage 150 is arranged on the outer sleeve device 7. This guide cage 150 has the task of holding the outer sleeve device 7 against the bore hole wall 9a with a friction which is low enough to be surmountable in the axial direction by means of the downward pressure of the drilling tube 3 during drilling and high enough to friction- lock against possible rotation under the influence of the drilling tube 3 as this rotates. The guide cage 150 comprises supporting units 200, which, during drilling, engage in the bore hole wall 9a. A series of drilling tubes are arranged in a connectable manner on the coupling device 1. Only the lowermost drilling tube 3 is visible in the figure. These drilling tubes can extend up to 4-5 kilometres or more downwards from the ground surface m.

The drilling tubes are joined to one another according to the drilling depth reached. The fact that the outer sleeve device is non-rotating during drilling

makes it possibile to guide the drilling device. To raise drilling tubes 4-5 kilometres can take up to 6-8 hours. With the aid of the present invention, the guidable core barrel 5 can be raised to the ground surface without all the drilling tubes needing to be raised. According to the invention, the core barrel can be provided with various projections (58a and 58b shown in Fig.

7), of which, when the core barrel is once again in its coupled position in the bore hole, one projection (58a, Fig. 7) acts upon a guide elbow (shown more clearly in Fig. 7) to guide the cutter head in a certain direction and another projection (58b, Fig. 7) to guide it in another direction. In this way, guidance can be achieved by changing the projection (58a and 58b in Fig. 7) on the core barrel 5. The coupling device 1 according to the invention can be used to raise the core barrel to the ground surface with a considerable gain in time. Other solutions of influenceable guide means 35, for example a slidable screw bolt (not shown), different lengths of the actual core barrel 5, inserts (not shown) of various types, etc., can of course be used to act upon the guide device, which can be the guide elbow 57, as it is known. The drilling tubes 3 have the task of transmitting drilling pressure, torque and drilling fluid for lubrication and cooling from a drilling machine (not shown) to, inter alia, the cutter head 31. The coupling device 1 further has a connectable coupling sleeve 13, which is arranged such that it can be connected with the drilling tube 3. The coupling device 1 provides the facility of disconnecting the core barrel 5 from the drilling tube 3 when the core barrel 5 is to be raised. The cutter head 31 and the outer sleeve device 7 are likewise disconnected. Only the core barrel 5 containing the sample or the product is raised through the drilling tube 3, using, for example, a steel wire. The steel wire is during drilling arranged in the drilling tubes and extends from the ground surface m to a core barrel head (not shown) according to known technique. As the rock drill 6 makes its way deeper and deeper, the steel wire is being fed. When it is time for raising the core barrel 5 and this is disconnected, the steel wire is hoisted to the ground surface m, wherein the core barrel head together with a radial locking unit 11 and the

core barrel 5 are being brought to the ground surface m. When the core barrel 5 is emptied at the ground surface m, this is lowered through the drilling tubes to a position in the outer sleeve device 7 for drilling. Since the core barrel rotates during drilling, the steel wire at its lower part is adapted with a free rotary connection element (not shown).

The remaining drilling equipment is left in the rock hole. The advantages of this are, inter alia, that the guide position is adjusted with the fixed position of the outer tube 7 in the bore hole, in that the said outer tube very often has a slight deflection in relation to the articulated section 30. In this way, no new guidance adjustment needs to be made if it is wished to continue in this direction. An articulated section 30 can be constituted according to the invention as a guide elbow 57. The guide elbow 57 can produce a deflection of the core barrel 5 for guidance of the rock drill.

In Fig. 2, according to the invention based on a first embodiment, a coupling device 1 is shown in cross section, in which the coupling device 1 is in a coupled state. In Fig. 2 and the figures described below, the inner parts, when these are shown, such as core barrel 5, drive shaft 29, etc., are not illustrated in cross section. In Figs 2-5, three different embodiments of the invention are shown.

Fig. 2 reveals that the drilling tube 3 is threaded onto the connectable coupling sleeve 13. This coupling sleeve 13 has a number of recesses 18a, which are also shown in Fig. 3. Inside the coupling sleeve 13 are four cylinder bodies 17a, in this embodiment so-called cylinder bodies 17a in the form of rollers, arranged in a carrier housing 15. A thread 60 for a core barrel head (not shown) is produced on a piston 63 belonging to the carrier housing 15. The core barrel head (not shown) has lugs (not shown), which, in the coupled state of the coupling device 1, are placed against the inner wall 64 of the drilling tube 3. In this way, the core barrel head (not shown)

acts upon the carrier housing with a compression force. The above-described core barrel head is configured according to the prior art. All axial load is absorbed by the core barrel head. The various core barrel heads which are available on the market are suited to the present invention. That is to say, the piston can be adapted to the known core barrel heads directly or via an adapter. The compression force from the core barrel head is applied to/activated on a radial locking unit 11. The radial locking unit 11 comprises, inter alia, the carrier housing 15.

The carrier housing 15 is held by means of the piston 63 such that it cannot move upwards. The axial pressure upon the drilling tube 3 is thus transmitted via the lugs of the core barrel housing to the carrier housing 15.

The carrier housing 15 transmits the axial pressure, via a thrust bearing 21 by way of a projection 22, to the outer sleeve device 7. The axial pressure upon the cutter head 31 is transmitted from the drilling tube 3 by way of the coupling device 1 via the drive shaft 25 and the core barrel 5.

The lugs are folded-in in the core barrel head when the core barrel is to be raised to the ground surface. Prior to the raising of the inner parts such as the core barrel (denoted by the reference notation 5 in Figs 1 and 6-8) and the drive shaft 25, a wire (not shown) is coupled to the core barrel head, which wire runs to the ground surface. When the coupling device 1 is to assume its coupled position, that is to say when the carrier housing 15, with its cylinder bodies 17a in a retracted position, approaches the coupling sleeve 13 and its recesses 18a, the carrier housing 15 is moved first with its cylinder bodies 17a in the drilling tube 3 into a retracted position (shown with dashed contour in Fig. 3). When the carrier housing 15 lands within the region of the recesses 18a in the coupling sleeve 13, an expansion sleeve 96 is moved with the aid of a piston 63 into a position which presses the cylinder bodies 17a outwards in the direction of the bottoms 70 of the recesses 18a (shown in Fig. 3) in the coupling sleeve 13. The carrier housing 15 is thereby locked

in the coupling sleeve 13 and a torque can be transmitted from the drilling tube 3 to the drive shaft 25, which is connected to the carrier housing 15.

When uncoupling is to occur, the carrier housing 15 is conducted upwards and, once the carrier housing 15 is in position within the region of the transition between the coupling sleeve 13 and the drilling tube 3, a bevelled edge 80 of the cylinder bodies 17a guides the cylinder bodies 17a into the inner position and a passage can take place through the drilling tube 3.

Firstly, for the decoupling operation, the drilling machine (not shown) is stopped. Then the inner parts, such as the drive shaft 25 of the drilling device 1, are lifted a little bit. The coupling sleeve 13 is thereby released as a result of the expansion sleeve 96 releasing the cylinder bodies 17a from their recesses 18a made in the coupling sleeve 13. The cylinder bodies 17a fall into the carrier housing 15 as a result of the expansion sleeve 96 departing from its locking position. The cylinder bodies 17a are pushed inwards in the carrier housing by virtue of them having a bevelled edge 80, which, upon the upward motion, is pressed against the inside of the drilling tube 3 (not shown). The radial locking unit 11 with the carrier housing 13 can thus run freely inside the drilling tube. When the drill arrangement is raised, the core barrel head (not shown) releases its lugs (not shown), which means that the core barrel head (not shown), together with, inter alia, the piston 63, the carrier housing 15, the expansion sleeve 96 with the cylinder bodies 17a, the thrust bearing 21, the drive shaft 25 and the core barrel 5 (shown, for example, in Fig. 1), can be raised up.

Drilling fluid is transported under pressure from the ground surface through the drilling tube 3, passes through the carrier housing and is transported onwards through the duct 70 down to the cutter head 31 (shown in Figs 1 and 8). The drilling tube 3 is connected to the coupling sleeve 13 with the aid of threads 13a. To prevent any loss of drilling fluid pressure between the coupling sleeve 13, which rotates during drilling, and the outer sleeve device 7, which is non-rotating during drilling, an outer sealing sleeve 77, which

rotates during drilling, is fixedly disposed on the coupling sleeve 3.

Arranged between an inner sealing sleeve 78 and the outer coupling sleeve 77 there are seals, made, for example, from ceramic material. The seals can be traditional chevron packings. Other types of seals can also be used. The inner sealing sleeve 78 is non-rotating during drilling, since it is fixedly connected to the outer sleeve device which is non-rotating during drilling. A complete sealing between the coupling sleeve 13 and the outer sleeve device 7 is thereby achieved.

In Fig. 2, the thrust bearing 21 is arranged between the carrier housing 15 and the drive shaft 25. The thrust bearing 21 has the task of using a part 2la, which is non-rotating during drilling, to transmit a pressure to a shoulder 21b of the inner sealing sleeve 78, which is non-rotating during drilling and which, in turn, has been configured to press upon the outer sleeve device 7 which is non-rotating during drilling. The outer sleeve device 7, which is non-rotating during drilling, can therefore be moved downwards at the same time as the cutter head 31 bores downwards and creates the bore hole 9.

A bevel 100 has been arranged in the outer sealing sleeve 77, which bevel 100 bears against a corresponding bevel 101 of the inner sealing sleeve 78.

The bevel 100 has an angle a of approximately 15-30 degrees. The configuration of the bevel according to the invention means therefore that the coupling sleeve 13 and the outer sealing sleeve 77, when uncoupling occurs, can adequately grip the inner sealing sleeve 78. Because large forces are applied, a 90-degree bevel would not provide sufficient grip. The bevels 100,101 have an inclination from inside the centre of the coupling device 1 and out in the downward direction. Should the inclination of the bevels be configured such that it is angled upwards, then when the inner drilling arrangement is raised, these bevels would have to be configured on sleeves of greater diameter in order to obtain acceptable strength.

Fig. 3 shows a cross section along the line A-A in Fig. 2 according to the first embodiment described above. In the figure, the cylinder bodies 17a are shown with dashed lines in a folded-in position in the carrier housing 15.

The expansion sleeve 96 is located so as to effect a pushing-out of the cylinder bodies 17a into an outer position (not illustrated) in the coupling sleeve 13 corresponding to recesses 18a and their bottoms 70, thereby achieving a coupling. The piston 63 is centrally located in the coupling device 1 and, in coupled position, holds the guide cylinders 17a in locked position in the recesses 18a in the coupling sleeve.

Fig. 4 shows a section A-A in Fig. 2 according to a second embodiment. The reference notations in this figure correspond to those in the previously shown figures. According to this embodiment, the four locking bodies are configured as rhomboids. With the aid of an expansion sleeve 96, these fall into corresponding recesses 18b in the same way as the locking cylinders described in the first embodiment in Figs 2-3.

Fig. 5 shows diagrammatically in side view a splineway 14 included in the coupling device 1 according to a third embodiment and in Fig. 5a is shown a cross section, along the line A-A in Fig. 5, of the said splineway 14. The advantage of a splineway 14 is that it is space-saving. Splines 16 are resiliently arranged on this sleeve 14. During the coupling operation, a conical expansion sleeve 96, which has a slightly different configuration from the splineway in the previously described illustrative embodiments, is forced downwards. As a result of the conical configuration of the said expansion sleeve, the splines 16 are forced outwards and brought into engagement with ridges 16a arranged in the coupling sleeve 13. The radial force is thereby able to be transmitted from the coupling sleeve 13 to the drive shaft 25.

Fig. 6 shows diagrammatically a guide cage 150 described in an application

accompanying the present application. The guide cage 150 comprises supporting units 200, which are illustrated as blocks. The supporting units 200 are applied with the aid of the drilling fluid pressure to the wall 9a of the rock hole 9. The guide cage 150 has the task of keeping the outer sleeve device 7 from rotating during drilling. The supporting units 200 are therefore arranged to be held against the bore hole wall 9a with a friction low enough to be surmountable in the axial direction by downward pressure of the drilling tube 3 during drilling and high enough to friction-lock against possible rotation under the influence of the drilling tube 3 when this rotates.

Fig. 7 shows an articulated section, such as a guide elbow 57, or in this application otherwise called section 30 which laterally displaces the centre, which can be acted upon in a cost-effective manner by the coupling device 1 according to the invention. That is to say, the core barrel 5, which, provided with, for example, various projections 58a, 58b, acts upon this guide elbow 57, can be raised to the ground surface with little work effort. At the ground surface, a core barrel 5 having a new projection 58b is applied, which acts upon the guide elbow 57 to achieve a new deflection of the core barrel 5 and hence of the outer sleeve device 7, which is non-rotating during drilling. The outer sleeve device 7, which is non-rotating during drilling, serves according to the invention as a guide tube, whilst the core barrel 5 rotates with the cutter head 31. A number of solutions can be devised for adjusting devices using the core barrel. This lies outside the scope of the present invention and is not therefore discussed here any further. In Fig. 7, the guide elbow 57 comprises an axially movable bearing part 122, which can hold the core barrel 5 in a linear position with the outer sleeve device 7, which is non- rotating during drilling. The guidance is effected by virtue of the fact that a variable control cam 124 is placed in the guide elbow 57. This produces a straight drilling. In the guidance operation, the movable bearing part 122 is moved downwards with the aid of various projections 58a, 58b on the core barrel 5 and brings about a deflection of the core barrel 5. This means that

the outer sleeve 7 can also be deflected away. A number of hard-metal sleeves 126 are folded-in in the outer sleeve part 125 in order to produce a centring of the guide elbow 57 in the bore hole. Fig. 7 shows when the guide elbow 57 is acted upon with a projection 58a of such a length that the axially movable bearing part 122 is not taken up by the projection 58a of the inner tube 5. This means that an outer sleeve part 125, which is non-rotating during drilling, of the axially movable bearing part 122 is unaffected. The position illustrated in the figure shows an unaffected position of the variable control cam 124. This position has an effect as a centring bearing and achieves a straight drilling. As has been described above, when a particular guidance is desired, a core barrel 5 having a lengthy projection 58b is applied, which acts upon the axially movable bearing part 122, which, in turn, acts upon the outer sleeve part 125 of the variable control cam 124. The axially movable bearing part 122 is taken up by a return spring 128, which return spring 128 is arranged to push back the axially movable bearing part 122. The return spring 128 has its stop configured in the downward direction by a locking washer 129 disposed on the outer sleeve part 125. A deflection is thus effected through lateral displacement of the core barrel 5, which, in turn, acts upon the cutter head via a flexible mounting 139 at the lower part of core barrel 5. A guidance function of the drill is therefore achieved. A water duct 160 is suitably configured in the guide elbow 57 to allow the drilling fluid to pass through the guide elbow 57 between the outer sleeve device 7 and the core barrel 5 down to the cutter head (not shown).

In Fig. 8 and Fig. 8a are shown a removable cutter head 31 (Fig. 8) according to the prior art and a core lifter sleeve 142 (Fig. 8a) disposed on the core barrel 5. The core barrel 5 is configured with splines 131 at its lower end and is released when raised from the actual cutter head 31, whereupon the cutter head 31, together with the outer sleeve device 7, the guide elbow 57, the guide cage 150, the coupling sleeve 13 and the drilling tube 3, can be left in the bore hole.

A flexible mounting 139 is placed between the core barrel 5 and the ends of the outer sleeve device 7 on the cutter head 31 and at a distance from the section 30 which lateral displaces the centre (Figs 1 and 7), to allow deflection at the cutter head 31.

A projection 135 is disposed at the lower end of the core barrel 5. This projection 135 transmits the feed pressure from a projection 145 of the core barrel 5 to a splineway 136 connected to the cutter head 31. Recesses 137 for splines 131 are configured in the splineway 136.

Seals 138 are arranged on both sides of the flexible mounting 139 for the drilling fluid wash in the cutter head 31. A locking ring 140 is placed at the lower end of the sleeve device in order to detain the flexible mounting 139 and the seals 138. A core lifter spring 143 is arranged at the lower end of the core barrel 5 in order to collect the drilling product, etc. when the core barrel is full of the drilling product, etc. and is to be raised to the ground surface for emptying.

After the core barrel 5 has been emptied at the ground surface m, the inner parts are moved back down into the drilling tube 3 and lowered with the aid of the said wire to a landing position in the outer parts. Landing is effected softly and smoothly according to the invention. The splines 131 of the core barrel 5 are fitted into corresponding recesses in the cutter head 31. At the same time, the locking cylinders 17 of the carrier housing 15 are extended with the aid of the expansion sleeve 96, which, in the course of the landing procedure, forces the locking cylinders 17 outwards into corresponding recesses in the carrier housing 15. Prior to coupling taking place, the locking cylinders 17 are held in the inner position with the aid of the inside 64 of the drilling tube 3. According to the invention, the core barrel 5 which has been applied to the drive shaft 25 has the length or projections which provide the

desired guidance. To prevent a hard landing, between the outer carrier and the non-rotary outer tube a large axial play X (see Fig. 2) is obtained.

According to the invention, when the inner parts are lifted, the outer parts therefore remain in their position, inter alia due to the deflection of the outer sleeve device 7, and are also fixed in the bore hole 9 (not shown) due to their own weight.