WO2009132831A2

WO2009132831A2 - Grip head for an earth boring unit

Info

Publication number: WO2009132831A2
Application number: PCT/EP2009/003100
Authority: WO
Inventors: Dietmar Scheider
Original assignee: Dietmar Scheider
Priority date: 2008-04-29
Filing date: 2009-04-29
Publication date: 2009-11-05
Also published as: CN102037207A; US20110114391A1; WO2009132831A3; DE102008021491A1; EP2268888A2

Abstract

The invention relates to a grip head for an earth boring unit, comprising a hollow shaft (3), wherein a sleeve (1) is arranged coaxially on the hollow shaft (3) to slide relative thereto, said sleeve having at least one end region (1b) widening particularly at the bottom thereof particularly in the form of a cone and at least two clamp jaws (2) which can be displaced radially relative to the hollow shaft (3) are arranged in the hollow shaft (3) and/or on the sleeve (1), comprising stop faces (2b) cooperating with the widening end region (1b), such that on movement of the end region (1b) over the clamp jaws (2) said jaws may be pressed inwards and a first tensioning mechanism and form a first tensioning device for an upper end of a casing (9) which may be introduced from below into the sleeve, in particular such that a cooperation between clamp jaws (2) and casing (9) permits transmission of a torque between ween the hollow shaft (3) and casing (9) and a second tensioning mechanism is provided in the hollow shaft (3), by means of which the introduced / introducible casing (9) may be fixed at the upper rend region thereof in the axial direction, in particular fixing a casing (9) in the axial direction against gravity relative to the grip head, wherein a flush tube (14) of supplying a flushing fluid is arranged coaxially in the hollow shaft (3) and fixed in rotation relative thereto the lower region of which is enclosed by an annular balloon (11) which may be pumped up with a fluid, in particular a liquid.

Description

Clamping head for an earth boring machine

The invention relates to a clamping head for a Erdbohranlage, comprising a hollow shaft, wherein coaxially on the hollow shaft, a sleeve is arranged displaceably to this, which has at least one, in particular downwardly flared, in particular conically widening end portion and wherein in the hollow shaft and / or at the sleeve at least two radially displaceable to the hollow shaft clamping jaws are mounted, which have at their radially outer end with the expanding end portion cooperating contact surfaces, so that by pushing the end portion of the clamping jaws these are radially inwardly pressed and a first clamping mechanism for a form down into the sleeve insertable / imported upper end portion of a casing, in particular so that a torque between the hollow shaft and casing is transferable by an interaction between clamping jaws and casing and wherein in the hollow shaft, a second clamping mechanism is provided, by means of which an imported / insertable casing at its upper end portion in the axial direction can be fixed, in particular to keep a casing in the axial direction against gravity relative to the chuck stationary.

Such a clamping head has been disclosed for use in earth boring by the same applicant in the German patent application DE 10 2008 012 729.9. Also, the clamping head described there, the interaction of which has been described with a drill pipe, is basically suitable, instead of a drill pipe to include a casing as described in the introduction. It may be provided in a first possible embodiment that the second clamping mechanism as well as the first clamping mechanism can be actuated by moving the sleeve which is displaceable on the hollow shaft. This has the advantage, for example, that only one drive must be present in order to move the sleeve.

In another alternative embodiment, it can also be provided that the sleeve for actuating the first clamping mechanism by means of a first drive, in particular hydraulic drive relative to the hollow shaft is displaceable and the second clamping mechanism is actuated with a second drive independent of the first drive, in particular both Drives are fixed with one side to a common support element. Thus, both tensioning mechanisms can be operated independently, e.g. in chronological succession or else at the same time, for example by synchronization in a superordinate control unit controlling the drives. The drives can be in both versions, e.g. each comprise at least one, preferably a plurality of evenly distributed in the hollow shaft cylinder-piston units.

Casings are used in the prior art in conjunction with ground wells to stabilize the walls of the well after drilling and lifting of the drill string. For this purpose, it is therefore intended to introduce a so-called casing into the bore performed. The casing itself is hollow, so that the inner free diameter of the bore is maintained, but with the casing wall stabilizing the well over its length.

In the prior art, the problem is known that bores do not always take a precisely straight course, so that it is sometimes difficult to introduce a casing after lifting a drill string in the introduced into the ground hole. The object of the invention is therefore to provide a clamping head of the type mentioned above, which offers the possibility to subsequently introduce a casing in created holes in the ground and this particular not only a plugging, but in particular to allow a screwing of the casing into the well. In this case, to achieve a facilitated introduction of a casing into a borehole additionally a fluid purge, in particular a water rinse are used, wherein a concentration of the rinsing force of the rinsing fluid is to be achieved in the borehole.

This object is achieved in that a flushing pipe for the supply of a rinsing liquid coaxially in the hollow shaft and rotatably disposed therewith, the lower region is surrounded by an annular, with fluid, in particular a liquid inflatable balloon.

An essential core idea in the construction of the clamping head according to the invention is that on the one hand by the above-mentioned two clamping mechanisms and here in particular by the sliding jaws, by the radial displacement of a introduced into the clamping head casing can be firmly clamped to the rotation of the clamping head also to turn the casing in the soil in rotation. It is ensured by the aforementioned second clamping mechanism that a particular upper portion of the casing is held firmly in the chuck, in particular against the action of gravity, so as to prevent slipping out in the axial direction of the casing from the chuck.

There is thus the possibility, as already described in the aforementioned document DE 10 2008 012 729.9, to introduce a chuck tube into the ground with the chuck head in the same way as with the drill pipe described in the aforementioned document, wherein now in this invention Execution by the coaxial arrangement of the flushing pipe within an imported or insertable casing the possibility Rinse liquid is pumped through the flushing pipe into the casing, whereby the liquid passes through the casing to its lower end and in a region between the outer wall of the casing and the borehole inner wall to a loosening of the borehole wall, to a kind of lubricating effect and thus to a lighter Insertion of the casing into the borehole contributes.

In order to achieve a good operative connection between the clamping jaws and a casing, the clamping jaws of the first clamping mechanism can be made e.g. have a surface design of the cooperating with a casing surface. For example, the surface may have a structuring and / or preferably a coating which acts as a friction lining. Such a coating may e.g. the activity-enhancing particles, e.g. Sand, diamonds etc. Thus, the force can be introduced over a large area in the casing, whereby local damage fails.

It can be achieved according to the invention by the inflatable balloon, which is annularly around the flushing pipe in a region between flushing pipe and inner wall of the casing, a seal between the flushing pipe and casing, so that prevents the pumped with high pressure washing liquid up through escapes the clamping head.

To ensure this, it can be provided in a preferred embodiment that by inflating the balloon, an annular region which is formed between the flushing pipe and an inserted, the flushing tube coaxially surrounding casing, is sealable against the rinsing liquid. Thus, it is preferably achieved by the inflation that the balloon increases in volume, is always inflated and thus applies to the inner region of the casing wall and to the outer region of the Spülrohrwandung and thus closes this annular area pressure-tight. This can be achieved in particular by the selected pressure when inflating this balloon, the tightness against different levels of Flüldrücke. As a fluid, which For example, water, but preferably a hydraulic fluid, in particular an oil, is pumped into the balloon.

In order to enable the inflation, it may be provided in a preferred embodiment that the annular balloon is formed of a flexible, in particular elastic material. Thus, on the one hand, the flexibility ensures that the balloon automatically adapts to the contours that are present in the ring area between the flushing pipe and the casing pipe as a result of the inflation.

In addition, the preferred resilience of the balloon also ensures that fluid pumped into the balloon for pumping up will automatically escape from the balloon by the inflated elastic material tending to contract again and so pumped Fluid pushed back from the balloon.

However, it may also be provided to not only pump the fluid into the balloon for inflation, but also to pump the fluid out of the balloon to release the pressure. Both for the pumping as well as for an optionally provided pumping out of the fluid, a separate pump can be used or even a pump that is used anyway in a Erdbohranlage with such a clamping head according to the invention.

In a further preferred embodiment, it can be provided that the balloon is attached to the flushing pipe, whereby the balloon is prevented, in particular in a state when it is not inflated, from shifting in the axial direction relative to the flushing pipe. The attachment thus always achieves an optimum position relative to the flushing pipe and relative to an imported casing. In particular, the attachment may be chosen such that the balloon is arranged above the lower end of the flushing pipe and at the same time relative to an inserted into the chuck casing below its upper end.

In an embodiment according to the invention, it can furthermore be provided that the balloon has a fluid supply which can be fed with fluid from a rotary feedthrough fastened to the flushing pipe. For example, such a rotary feedthrough having an inner fluid-carrying ring member which is rotatably connected to the flushing pipe and is connected to the fluid supply and an outer, opposite the inner ring member rotatable fluid-conducting ring member which is non-rotatable relative to a surrounding machine structure and by means of the fluid also at a rotation of the ring parts to each other to the inner ring member can be fed.

This ensures that during a rotation of the clamping head, in order to achieve a drilling introduction of a casing in the soil, no twisting of the fluid supply to the flushing pipe or relative to the chuck takes place, since the fluid supply between the balloon and a part of the rotary feedthrough extends which is non-rotatable with the flushing pipe, so that rotates with a rotation of the clamping head, the fluid supply.

By an outer rotatable ring member on the rotary feedthrough, which is rotationally fixed relative to the surrounding machine structure, the supply of fluid to the rotary feedthrough and then to the balloon can be carried out by a surrounding machine structure, which is ensured here by the rotating decoupling between the outer and inner ring member, that the supply to the rotary feedthrough and the outer ring undergoes no twisting during the rotational movement of a clamping head relative to a surrounding machine structure.

A preferred embodiment of the rotary feedthrough can provide that this comprises three fluid channels, so in particular so technically three rotary unions are realized in one component. There is therefore the possibility of using this Rotary feedthrough three different working fluids independently from the outside, ie a surrounding machine structure to supply to a rotating chuck. In this case, it can be provided, for example, that a fluid channel for the fluid supply and / or fluid discharge to and / or from the balloon care, with two further fluid channels for supplying fluid to each at least one cylinder-piston unit for the axial movement of the sleeve the hollow shaft are inserted in opposite directions.

For example, an actuation of the clamping mechanisms of the clamping head by a displacement of the movable sleeve relative to the hollow shaft, wherein for this actuation of the sleeve for displacement in the axial direction for each of the two possible directions, at least one cylinder-piston unit is provided. Thus, therefore, at least one cylinder-piston unit can be used to move the sleeve down relative to the hollow shaft and at least one other to move the sleeve relative to the hollow shaft upwards. Each of these cylinder-piston units can receive its working fluid from one of the channels of the rotary union mentioned above. It is thus possible, with only a single rotary feedthrough to supply all the necessary working fluids to the clamping head according to the invention.

An embodiment of the invention is shown in detail in the following figure.

1 shows a clear sectional view of a clamping head according to the invention, comprising a hollow shaft 3, on which a coaxial sleeve 1 is arranged, which is also referred to as a clamping head bell and whose lower portion widens in a funnel shape / truncated cone down. The inner wall region of this lower, funnel-shaped widening region of the displaceable sleeve forms actuating surfaces for radially outer ends or contact surfaces of clamping jaws 2, which are thus automatically displaced radially inwards by an axial downward movement of the sleeve. In this case, these clamping jaws 2 can be mounted displaceably on the sleeve 1 and / or on the hollow shaft 3.

Visible here in the illustration of Figure 1 is a introduced into the chuck head casing 9, wherein the clamping jaws 2 are applied by a downward Move the outer sleeve 1 in the radial direction from the outside to the casing of the casing 9 and a frictional engagement and or form a traction. This makes it possible to transmit torque by turning the entire clamping head according to the invention to the casing 9 and to bring this rotating in a borehole.

The figure 1 further shows a second clamping mechanism which is formed by a plurality of clamping elements 4 arranged around a casing 9, wherein each clamping element 4 comprises a radially outer guide surface 4a, which cooperates with a guide surface 3a in the interior of the hollow shaft 3, so that Moving a clamping element 4 in the axial direction, in particular down, a radial movement of the clamping element, in particular inwardly, is effected.

In this case, it is provided, as mentioned at the beginning, that the individual clamping elements 4 of the second clamping mechanism are moved when, by means of the sleeve 1 arranged outside on the hollow shaft 3, an axial movement is carried out, in particular in the usual working position downwards. For this purpose, a mechanical operative connection between the outer sleeve 1 and inner clamping elements 4 is provided, which may extend, for example, through the wall of the hollow shaft 3.

It can thus be achieved that, by moving the sleeve 1 on the outside of the hollow shaft 3, the clamping elements 4 arranged in the hollow shaft 3 are carried along in the same direction of movement at least in regions. By a corresponding arrangement of the respective guide surfaces 3a, 4a of the hollow shaft 3 and the clamping elements 4 is thereby effected that when moving in the axial direction automatically also moving in the radial direction of the clamping elements 4 takes place in particular so that these form fit around one of the hollow shaft encompassed casing 9 can be placed around.

The kinematic implementation of an axial movement of the clamping elements 4 in a radial movement taking place simultaneously can take place, for example, in that the cooperating guide surfaces 3a, 4a on clamping element 4 and Hohlwelle3 relative to the center axis of the hollow shaft 3 have a tendency, especially when viewed in section have an acute angle to this.

A form fit between the clamping elements 4 and a casing 9 can be achieved by the clamping elements 4 provided at the radially inner regions lying contact surfaces 4b are adapted in terms of their design to a casing 9 in particular in the upper region, for example, to the diameter of a Casing 9, so that these contact surfaces 4b eg at least have a cylindrical portion-shaped surface area and / or may also be adapted to a shoulder 9a, which is provided on the casing, or a step 9a at which the diameter of the casing changes, especially in the direction from top to bottom tapers.

Such a taper can take place at said shoulder or step 9a, for example, by a right-angled step relative to the axis of the casing, or also by a conical step or any other shapes. The contact surfaces 4b of the clamping elements 4 accordingly also have surface areas which are adapted to such a shoulder or step 9a, so that by a positive connection between the clamping elements 4 and a casing 9 due to the investment of the clamping elements 4 at such a shoulder or step 9a an axial lifting force or holding force can be exerted on the casing when the contact surface 4b at the shoulder / step 9a rests without the clamping elements 4 in the axial direction relative to the casing 9 slip.

In order to obtain a corresponding guide surface 3a as counter surface for those guide surfaces 4a on the respective clamping element 4, it may be provided in the embodiment shown here that such a guide surface is formed inside the hollow shaft 3 by a radially inwardly projecting annular region 3b, the inner Recess forms a frustoconical lateral surface which is arranged coaxially about the center axis M of the hollow shaft 3, in particular wherein said frustoconical surface is tapered downwards in the usual working position of the clamping head. Straight down through the taper is achieved here that during a downward movement of the clamping elements 4 within the clamping head, a displacement of these clamping elements 4 takes place radially inward, when the guide surface 4 a on the clamping element 4 on the frustoconical lateral surface 3 a of the annular region 3 b slides along.

The formation of a frustoconical surface on the inner ring portion inside the hollow shaft has manufacturing advantages, since such a frustoconical surface can be achieved in a simple manner by an inner boring of a shaft. For example, for this purpose, a hollow shaft 3 are made of a solid material.

The radially outer guide surfaces 4a of the clamping elements 4 can furthermore be designed as outer conical surface areas corresponding to the frustoconical lateral surface. This results if both the guide surfaces 4a are formed on the clamping elements 4 as well as on the projecting annular region frustoconical, or form a portion of a frusto-conical lateral surface, that there is only one specific position in which the respective guide surfaces 4a of Clamping element 4 and ring portion 3b form-fitting contact, since outside this particular position, the respective diameters of the individual conical surfaces relative to the center axis M of the hollow shaft 3 do not match one another.

It is therefore provided in a preferred embodiment that the respective guide surfaces 3a, 4a of the clamping element 4 and ring portion 3b are adapted to each other so that the positive engagement between these corresponding guide surfaces increases with increasing positive engagement between the clamping elements 4 and a liner 9, ie in particular when the clamping elements 4 are pushed through the sleeve 3 down and thus simultaneously inward.

Thus, the second clamping mechanism can be designed so that in the moment when optimal positive engagement between the clamping elements 4 and a liner 9 is also an optimal positive engagement between the corresponding guide surfaces 3a, 4a is given. It will be optimally transferred the respective forces between the surfaces in this way while avoiding too high local pressures. Such an embodiment also has the advantage that in a case when there is no positive connection between the clamping element 4 and casing 9 or between the corresponding guide surfaces, these guide surfaces do not rest over their entire surface area but only selectively or linearly to each other, so that the Friction between the guide surfaces is reduced in this position of the clamping elements.

The same configuration can also be given between the guide surfaces on the clamping jaws 2 of the first clamping mechanism and the conically widening end portion of the outer sleeve 1. All of the above statements regarding the construction of the guide surfaces between the clamping elements of the second clamping mechanism and the frusto-conical lateral surface of the annular region apply analogously to the clamping jaws 2 of the first clamping mechanism and the frustoconical widening end portion of the sleeve first In this embodiment, it is further provided that a clamping element 4 on a parallel to the hollow shaft axis M arranged bolt 6 is displaceable in the axial direction, which penetrates a clamping element 4 and arranged thereon a radial outwardly facing projection. This has the advantage that when using a plurality of individual clamping elements 4, these each have a guide and can only move along this guide in the axial direction in the interior of the hollow shaft 3.

For example, a tilting of the clamping elements 4 relative to the casing 9 is avoided. In order to simultaneously allow in addition to the guided movement in the axial direction that during an axial movement, a radial movement in particular inward is possible, it is preferably provided that such a bolt 6 rests in a recess of the clamping element 4 and its projection, the extends in the radial direction, that is formed, for example, in the manner of a slot in the radial direction. Thus, in a movement of a clamping element 4 in the axial direction of this can be performed in the axial direction to the bolt 6 along this, but also simultaneously move perpendicular to the extension of the bolt 6 in the radial direction.

As mentioned above, it is provided according to the invention that the clamping elements 4 are actuated by a movement of the outer sleeve 1. For this purpose, an operative connection from the interior of the hollow shaft 3 to the outer sleeve 1 may be provided. In the embodiment shown here, the clamping elements 4 are movable by means of an arranged inside the hollow shaft 3 actuating element 5 in the axial direction, in particular in the direction of increasing positive engagement relative to the casing, wherein the actuating element 5 with the outside arranged on the hollow shaft sleeve 1 by at least one radial web is connected, which extends through a recess 3 c in the hollow shaft 3. It is preferably provided that such a recess 3c has a longitudinal extent in the axial direction of the hollow shaft 3, so that during a movement of the sleeve 1 in the axial direction, a web extending in the radial direction through such a recess 3c in this axial direction within the recess 3c is also movable. Thus, the movement of a sleeve 1 outside on the hollow shaft 3 thereby be transmitted to the interior of the hollow shaft 3, that the actuator connected by the webs 5 moves together with the sleeve 1. The movement of the actuating element 5 can then be transmitted in different ways to the clamping elements 4, for example, by an actuating element 5 acting directly and directly on a clamping element 4 or else by an actuating element 5 acting indirectly via interposed elements on a clamping element 4 ,

It may be provided in a particularly preferred embodiment, regardless of the nature of the action that an actuating element 5 is annular, wherein the inner recess is provided to surround a casing and wherein on the ring of this actuating element 5 all clamping elements 4 are simultaneously movable.

Furthermore, it can also be provided that the aforementioned bolts 6, on which the clamping elements 4 move along, are fastened to the actuating element 5. For example, a fastening can be effected by means of a screw connection, it likewise being possible for the bolts 6 to dip into guide bores which are provided on the annular region 3b which is formed in the hollow shaft for forming the frustoconical guide surface region. The bolts 6 are arranged at a distance from the center axis M around them, in particular in a uniform angular pitch, as well as the clamping elements 4 attached thereto movably. In a further preferred embodiment, a clamping element 4, in particular each clamping element 4, which is provided in the hollow shaft 3, in the direction of increasing positive engagement and thus in particular in a downward direction with respect to the usual working position against a restoring force be displaced. Such a restoring force may, for example, be exerted by a compression spring 7, in particular one which is supported on one side, in particular on the underside, on the tensioning element 4 and on its other side, in particular on the top of the annular area mentioned at the outset. In this case, such a compression spring 7 surround a bolt 6 also mentioned above.

The movement of the clamping elements 4 in the direction of increasing positive engagement against a restoring force has the advantage that the clamping element 4 can be pressed by this restoring force in the axial direction to a realized on a casing shoulder or step 9a. Thus, this causes that at the moment when the casing a clamping element 4 relieves this clamping element 4 is pushed out by the restoring force from the positive connection between the guide surfaces, that is pressed, for example, based on the usual working position upwards. As a result, the casing is released from the clamping elements 4. Such relief between casing 9 and the clamping element 4 can be achieved, for example, when a casing 9 is introduced into the soil and the clamping head moves relative to the casing 9 from the shoulder 9a of the casing 9a down in the axial direction of the casing. 9

In the embodiment shown here, which may also be omitted, it is provided to make an indirect action of the actuating element 5 on the respective clamping elements 4 by means of at least one compression spring 8 which is provided between the actuating element 5 and each clamping element 4. This ensures that a force does not act directly between the actuating and clamping element, but that the force is applied in each case by the compression spring 8. This has the additional advantage that over one certain predetermined axial movement path is always essentially the same force exerted on the clamping element 4, which results from the spring constant of the compression spring 8 as a function of the compression travel.

In an embodiment not shown here, it may be provided that such a compression spring 8 is arranged directly between actuating element 5 and clamping element 4 or, in a particularly preferred embodiment shown here, that such a compression spring 8 between an actuating element 5 and an intermediate element 5a, eg an intermediate ring 5a is arranged, which lies between the actuating element 5 and clamping element 4. In turn, all clamping elements 4 can be contacted simultaneously via such an intermediate ring 5a. Accordingly, spring elements 8 can be arranged between the mutually facing annular surfaces of intermediate ring 5a and actuating element 5, for example preferably at the positions at which the aforementioned bolts 6 extend from the actuating element 5 through the intermediate ring 5a and the clamping elements 4. Thus, each of these springs 8, for example, surround a bolt 6.

Such an embodiment according to the invention has the particular advantage that a sleeve 1 in the axial direction relative to the hollow shaft 3 is movable, initially by the indirect action of the actuating element 5 via the compression springs 8, the clamping elements 4 are movable into a positive connection with a casing 9, said after reaching this positive connection between the actuating element 5 and clamping elements 4 or actuator 5 and intermediate ring 5a an axial range of motion remains.

This axial movement range results in this case essentially in that upon reaching the positive connection, the compression springs 8 are not yet fully compressed. Accordingly, there remains an axial range of motion which is achieved by the compression of the compression springs 8 achieved in the case of positive locking up to the maximum possible compression of the compression springs 8, eg when the latter Windings abut each other or a separate stop is provided. The construction of the clamping head according to the invention is therefore such that due to this remaining range of motion even with existing positive connection between the clamping elements 4 and the casing, the outer sleeve 1 can be moved in this given range of motion in the axial direction until an effective closure between the jaws 2 of first clamping device and the casing 9 is formed. This conclusion can be given for example by a force and / or shape and / or frictional engagement between the clamping jaws 2 of the first clamping device and the casing 9.

It is thus achieved in a movement of the sleeve 1, in particular based on the usual working position in the axial direction down first a positive connection for axially fixing the casing 9 with the second clamping mechanism and after this is achieved, by moving the sleeve 1, the effective connection between the Clamping jaws 2 of the first clamping device and the casing 9, in order to be able to transmit a torque.

Thus, such a clamping head according to the invention makes it possible, in addition to the lifting forces exerted thereon, to simultaneously rotate the casing due to the possibility of transmitting torque and thus reduce the adhesion between the casing 9 and the soil, which considerably simplifies the introduction.

In reverse movement of the sleeve 1, ie based on a normal working position from bottom to top thus dissolves in reverse order, first the effective connection between the jaws 2 and the casing 9 wherein in the case when the casing 9 in the chuck hangs the positive connection between the clamping elements 4 of the second tensioning device and the drill pipe is initially maintained, since the casing over its shoulder / stage 9a, which was initially described rests with its weight on the clamping elements 4 and thus this now instead of the sleeve / Actuating element via the casing in the axial direction downwards and thus loaded in the direction of gravity, so that the positive locking remains self-locking.

Only as mentioned in the beginning, when the casing relieves the clamping elements 4, the clamping head lowers relative to the casing, whereby the positive connection between the casing 9 and the shoulder 9a and the clamping elements 4 is released and the clamping elements 4 by the spring load be moved in the axial direction upwards and thus release the casing.

In the device according to the invention, it is preferably provided to arrange the second clamping mechanism relative to a usual working position of the clamping head above said first clamping mechanism. It is also possible to reverse this arrangement.

The clamping head according to the invention shown here also shows in FIG. 1 that a flushing pipe 14 is connected to it in a rotationally fixed manner, which is arranged coaxially around the center axis M of the clamping head and in this embodiment by means of a cover plate 15 which covers the upper end of the hollow shaft 3 this is rotatably connected.

The lower end of the flushing pipe 14 terminates in the inner region of the clamping head according to the invention or below the lower end of the hollow shaft 3, so that it is ensured in each case that a introduced from below into the clamping head according to the invention casing 9, which surrounds the flushing pipe 14 coaxially , is arranged with its upper end above the lower end of the flushing pipe 14. In this case, it is provided that the upper region of the casing 9 and in particular a step or shoulder 9a arranged at this upper region can be reliably detected by the above-described tensioning elements 4, so that the casing is fixed in the axial direction. It can be seen here in Figure 1 further that in the annular region between the purge pipe 14 and casing 9, an annular ausgestalteter balloon 11 is arranged, which has a fluid supply 12, which also extends through the upper cover plate 15 and here at an inner ring portion of a Rotary feedthrough 13 is fixed, said inner ring portion is rotatably formed with the purge pipe 14. Thus, by means of a fluid supply to the rotary feedthrough 13 inflation of the balloon 11 can be achieved, so that the annular area between flushing pipe 14 and casing 9 can be closed tightly against the flushing liquid, which is pumped through the flushing pipe 14 into the casing 9. The pumped flushing liquid can thus spread only in the interior of the casing 9 down, but not against the balloon 11 upwards, so that the flushing liquid is pumped down in the casing 9 and softens the wellbore and so to facilitate insertion of the casing. 9 into the borehole care. In particular, it is ensured here by an inflated balloon that a built-up pressure of the rinsing liquid is completely retained within the rinsing tube 9.

As mentioned above, but not shown here in the figure, the rotary feedthrough 13 may not only have a channel for fluid transfer, but optionally several channels, in particular two more channels, not shown here cylinder-piston units for moving the outer sleeve 1 in axial direction relative to the hollow shaft 3 to effect.

With the structural design of the clamping head according to the invention shown here can thus be ensured that a casing is held both in the axial direction by the second clamping mechanism described here in the chuck and can be done by the first clamping mechanism with the jaws 2 torque transmission to the casing, at the same time rinsing liquid can be applied through the flushing pipe into the casing and a tightness between the flushing pipe and casing is guaranteed. With regard to all embodiments, it should be noted that the technical features mentioned in connection with an embodiment can not only be used or are used in the specific embodiment, but also in the respective other embodiments. All disclosed technical features of this invention description are to be classified as essential to the invention and arbitrarily combined or used alone. It is understood throughout the disclosure with the mention that a feature may be provided or a method step can be performed also an embodiment of the invention in which the feature in question is provided or a respective method step is performed.

Claims

claims

1. Clamping head for a Erdbohranlage comprising a hollow shaft (3), wherein coaxially on the hollow shaft (3) a sleeve (1) is arranged displaceably to this, which has at least one, in particular downwardly flared, in particular conically widening end portion (1b) and wherein in the hollow shaft (3) and / or on the sleeve (1) at least two radially to the hollow shaft (3) displaceable clamping jaws (2) are mounted, cooperating at its radially outer end with the widening end portion (1 b) Have run-on surfaces (2b), so that by pushing the end portion (1b) via the clamping jaws (2) they are radially inwardly pressed and form a first clamping mechanism for an insertable from below into the sleeve / inserted upper end portion of a casing (9) , In particular so that a torque between the hollow shaft (3) and casing (9) is transferable by an interaction between the clamping jaws (2) and casing (9) and wherein i n the hollow shaft (3), a second clamping mechanism is provided by means of an imported / insertable casing (9) at its upper end in the axial direction can be fixed, in particular to a casing (9) in the axial direction against gravity relative to the clamping head stationary hold, characterized in that a flushing pipe (14) for the supply of a rinsing liquid coaxially in the hollow shaft (3) and rotatably disposed therewith, the lower portion of an annular fluid-inflatable balloon (11) is surrounded.

2. Clamping head according to claim 1, characterized in that the second clamping mechanism by moving the sleeve (1) is actuated.

3. Clamping head according to claim 1, characterized in that the sleeve (1) for actuating the first clamping mechanism by means of a first drive (13), in particular hydraulic drive relative to the hollow shaft (3) is displaceable and the second clamping mechanism with one of the first drive ( 13) independent second drive (14) is actuated, in particular wherein both drives (13,14) are fastened to a common carrier element.

4. Clamping head according to one of the preceding claims, characterized in that by inflating the balloon (11) an annular region formed between the flushing pipe (14) and an introduced the flushing pipe (14) coaxially surrounding casing (9), against Rinsing fluid is sealable.

5. Clamping head according to one of the preceding claims, characterized in that the annular balloon (11) is formed of a flexible, in particular elastic material.

6. Clamping head according to one of the preceding claims, characterized in that the balloon (11) is attached to the flushing pipe (14).

7. Clamping head according to one of the preceding claims, characterized in that the balloon (11) has a fluid supply (12) which is fed from a flushing pipe (14) fixed rotary feedthrough (13) with fluid, in particular having an inner ring member, which is rotatably connected to the flushing pipe (14) and is connected to the fluid supply and has an outer relative to the inner ring member rotatable ring member, which is rotationally fixed relative to a surrounding machine structure and can be supplied by the fluid to the inner ring member.

8. Clamping head according to claim 7, characterized in that the

Rotary feedthrough (13) has three fluid channels, wherein a fluid channel for the fluid supply to the balloon (11) is provided and two fluid channels for supplying fluid to at least one cylinder-piston unit for the axial movement of the sleeve (1) on the hollow shaft (3 in opposite directions.

9. Clamping head according to one of the preceding claims, characterized in that the second clamping mechanism comprises at least two clamping elements (4), wherein each clamping element (4) comprises a radially outer guide surface (4a) with a guide surface (3a) inside the Hollow shaft (3) cooperates, so that by moving a clamping element (4) in the axial direction, in particular downwards, a radial movement, in particular inwardly, is effected.

10. Clamping head according to one of the preceding claims, characterized in that the clamping elements (4) each radially inner, in particular frusto-conical bearing surfaces (4b), by means of which these each form-fitting manner to a casing (9), in particular at an upper end of a casing (9) trained shoulder / step (9 a) can be applied in diameter.

11. Clamping head according to claim 10, characterized in that the

Shoulder / step (9a) is formed at right angles, in particular in that a sleeve (10) surrounds the upper end of the casing (9), whose lower end face the shoulder / step (9a).