EP2878761A1 - Annular bit for the drilling a foundation, and a method for detaching an annular bit for drilling a foundation from a sunken tube - Google Patents

Abstract

The invention relates to a drill bit (1) for drilling a subsoil. The drill bit (1) has a means for internally releasing a detachable connection between the drill bit (1) and a tube (2). The invention also relates to a method for releasing a drill bit (1) for drilling a subsoil from a pipe (2) in a sunk state, whereby a connection between the drill bit (1) and a pipe (2) is released internally.

Description

The invention relates to a drill bit for drilling a subsoil and a method for releasing a drill bit for drilling a subsoil from a pipe in the exhausted condition.

In the prior art drill bits for drilling a subsoil are known. Such drill bits are each attached to a pipe, which remains after completion of the hole as a so-called lost pipe in the ground. Such tubes, with which rotary motion and feed are transmitted to the respective drill bit and therefore must be firmly connected to the drill bit, are also referred to as single rod.

In the prior art methods for releasing a drill bit for drilling a subsoil from a pipe are known. In this case, the release of the drill bit from the pipe in abgegegeuftem state can no longer be done; Since with deeper holes usually the entirety formed from drill bit and pipe can not be pulled out of the ground, especially not if the diameter of the drill bit is larger than that of the pipe, the pipe must remain in the ground. Alternatively, elaborate double linkages are used in the prior art or a technically complex double head method is used for drilling.

The invention is based on the object to provide an improved drill bit for drilling a ground and an improved method for releasing a drill bit for drilling a ground from a pipe.

The object is achieved with respect to the drill bit by the combination of features according to claim 1 and with respect to the method by the combination of features according to claim 11.

Advantageous embodiments of the invention are the subject of the dependent claims.

The drill bit for drilling a subsoil has according to the invention a means for internally releasing a detachable connection between the drill bit and the tube. Internal release is to be understood as meaning a release in which it is not necessary to access the drill bit from the outside or the transition region of the tube to the drill bit.

A preferred embodiment of the invention provides that a recess is provided in the drill bit, in which a release bolt is inserted, with which the means for releasing is triggered. Preferably, the recess is arranged cylindrically and centrally in the drill bit. This makes it possible after completion of the hole in a simple manner, the actually built into the ground component, such as a sleeve pipe or icing, in the pipe - and thus in the ground - to insert. In this case, the unlocking bolt is attached as a head construction on the actually incorporated in the ground component. When the unlocking bolt reaches the drill bit and is inserted into its recess, the drill bit is automatically disconnected from the pipe, ie the release means is released. Subsequently, the pipe can be pulled out of the ground without the drill bit, while the drill bit remains as a lost component and the component that is actually to be installed in the foundation soil in the ground. Thus, unlike in the prior art, at least the pipe can be reused, resulting in great economic benefits, especially in deep holes.

A further preferred embodiment of the invention provides that the means for releasing the releasable connection between the drill bit and the tube comprises a number of radially displaceable locking bolts, which is displaceable from a locking first position to an unlocking second position. For this purpose, the locking bolts can be pulled out of corresponding recesses of the pipe. The release of the drill bit is thereby especially easy. In addition, a secure connection between the pipe and drill bit in the locking position is possible.

In this case, the number of locking bolts is preferably designed such that they at least partially protrude radially in their locking first position relative to an outer wall of a drill bit neck and do not protrude radially in their unlocking second position relative to the outer wall of the drill bit neck. Particularly preferably, the inner diameter of the tube is slightly larger than the outer diameter of the corresponding Bohrkronenhalses. A positive and very viable connection between the pipe and drill bit in the locking position is therefore particularly easy.

A particularly preferred embodiment of the invention provides that the means for releasing the releasable connection between the drill bit and the tube comprises a release sleeve causing the holding sleeve, which is arranged in the recess. The retaining sleeve is preferably axially displaceable for triggering the unlocking between the locking first position and the unlocking second position. As a result, the release of the drill bit from the tube is particularly easy.

Another preferred embodiment of the invention provides that the number of radially displaceable locking bolts is biased by spring force such that it is displaceable upon release from a locking first position to an unlocking second position. As a result, the release of the drill bit from the pipe with a particularly low expenditure of force and thus very easy even with very large drilling depths. The locking bolt is preferably biased by a coil spring, whereby the invention is easy to preload and compact buildable.

Another preferred embodiment of the invention provides that the drill bit neck a number of formations is arranged in a Number of corresponding Randausnehmungen the tube is axially inserted. As a result, in a particularly effective and simple manner, the drill bit with the tube form-fitting torque-connected, whereby the invention is suitable for transmitting a rotary motion with high torque, since the torque transmission in the locking position does not have to be done on the locking bolt, which in turn only for axial fixation - And thus comparatively filigree - must be designed. As a result, the invention is particularly safe, since the risk of unwanted jamming is particularly low.

Another preferred embodiment of the invention provides that the recess is provided with a cone. As a result, the introduction of the unlocking bolt is simplified because the unlocking bolt is automatically centered. Particularly preferably, the head of the unlocking bolt itself also has a conical shape and / or a fillet, whereby not only the introduction of the unlocking bolt into the recess, but also the axial passage of the unlocking bolt through the pipe is particularly simplified.

It is possible, by means of a biasing device to connect the drill bit with the tube under bias and lock in this position, so that when unlocking the drill bit from the pipe drill bit and pipe automatically space, so that the tube can then be easily pulled.

The inventive method for releasing a drill bit for drilling a subsoil from a pipe in a sunk state provides that a connection between the drill bit and a pipe is released internally. In this case, it is not necessary to access the drill bit or the transition region of the tube to the drill bit from the outside, as a result of which the tube can be pulled after completion of the drill hole and only the detached drill bit is a lost component. Preferably, the drill bit according to the invention is used. A preferred embodiment of the method according to the invention provides that a release bolt triggering the release of the drill bit is inserted into a centric, cylindrical recess arranged in the drill bit.

When the unlocking bolt reaches the drill bit and is inserted into its recess, the drill bit is automatically disconnected from the pipe, ie the release means is released. Subsequently, the pipe can be pulled without the drill bit from the ground, while only the drill bit remain as a lost component and actually to be incorporated into the ground component in the ground. Thus, unlike in the prior art, at least the pipe can be reused, resulting in great economic benefits, especially in deep holes.

A further preferred embodiment of the method according to the invention provides that the unlocking pin has a collar whose outer diameter is greater than the inner diameter of the holding sleeve and whose inner diameter is smaller than the inner diameter of the holding sleeve and that by inserting the unlocking into the recess a holding sleeve arranged therein is moved axially from a locking first position to an unlocking second position to trigger the release. The unlocking of the drill bit from the pipe can thus be made self-centering, so it does not require a planned centering of the release bolt. The release of the drill bit is so very easy.

A particularly preferred embodiment of the method according to the invention provides that a number of radially displaceable and prestressed locking bolts are unlocked by the axial displacement of the retaining sleeve from the locking first position to the unlocking second position, whereby the locking bolt of a locking first Move position to an unlocking second position. As a result, the release of the drill bit from the tube is particularly easy.

Another preferred embodiment of the method according to the invention provides that the number of locking bolts in its locking first position with respect to an outer wall of a Bohrkronenhalses at least partially survive radially and not protrude radially in their unlocking second position relative to the outer wall of the Bohrkronenhalses. Particularly preferably, the inner diameter of the tube is slightly larger than the outer diameter of the corresponding Bohrkronenhalses. A positive and very viable connection between the pipe and drill bit in the locking position is therefore particularly easy.

Embodiments of the invention are explained in more detail below with reference to drawings.

Figur 1

eine perspektivische, schematische Darstellung einer erfindungsgemäßen Bohrkrone,

Figur 2

eine perspektivische, schematische Darstellung eines zugehörigen Rohres,

Figur 3

einen Längsschnitt einer Ausführungsform der erfindungsgemäßen Bohrkrone im verriegelten Zustand,

Figur 4

einen Längsschnitt einer Ausführungsform eines zugehörigen Entriegelungsbolzens,

Figur 5

einen Längsschnitt einer Ausführungsform einer zugehörigen Haltehülse,

Figur 6

einen Längsschnitt eines Ausschnittes der Bohrkrone nach Figur 3 und

Figur 7

einen Längsschnitt der ersten Ausführungsform der erfindungsgemäßen Bohrkrone im entriegelten Zustand mit eingeschobenem Entriegelungsbolzen.

Show:

FIG. 1

a perspective, schematic representation of a drill bit according to the invention,

FIG. 2

a perspective, schematic representation of an associated pipe,

FIG. 3

a longitudinal section of an embodiment of the drill bit according to the invention in the locked state,

FIG. 4

a longitudinal section of an embodiment of an associated unlocking bolt,

FIG. 5

a longitudinal section of an embodiment of an associated holding sleeve,

FIG. 6

a longitudinal section of a section of the drill bit after FIG. 3 and

FIG. 7

a longitudinal section of the first embodiment of the drill bit according to the invention in the unlocked state with inserted unlocking pin.

• Figur 1 zeigt eine perspektivische, schematische Darstellung einer erfindungsgemäßen Bohrkrone 1, die zur Herstellung eines vertikalen Bohrlochs in einem nicht gezeigten Baugrund verwendet werden soll. Die Bohrkrone 1 weist an ihrem unteren Ende eine zylindrische Außenwandung auf, aus der vier Ausformungen 1.1 nach oben herausragen, aber gegenüber der zylindrischen Außenwandung am unteren Ende der Bohrkrone 1 nicht nach außen überstehen. Die Ausformungen 1.1 sind jeweils separate Elemente, die jeweils mit einer Schraube 1.2 im Grundkörper der Bohrkrone 1 befestigt sind. Die Bohrkrone 1 ist in ihrem oberen Bereich durch die Anordnung einer Ausnehmung 1.3 hohlzylindrisch ausgebildet, welche sich innerhalb eines Bohrkronenhalses 1.4 befindet und die an ihrem oberen Rand einen Konus 1.5 aufweist. Die Bohrkrone 1 dient dem drehfesten Anschluss an ein hier nicht gezeigtes und in den Figuren 2, 3 und 7 dargestelltes Rohr 2. In dem Bohrkronenhals 1.4 sind zwei Verriegelungsbolzen 3 angeordnet, die radial verschieblich und jeweils mittels einer Fixierplatte 3.3 im Bohrkronenhals 1.4 befestigt sind. Die Fixierplatten 3.3 stehen gegenüber der Außenwandung des Bohrkronenhalses 1.4 nicht nach außen über. Die Verriegelungsbolzen 3 sind radial verschiebbar, und zwar von einer verriegelnden ersten Position in eine entriegelnde zweite Position, wobei sie in ihrer hier nicht dargestellten verriegelnden ersten Position gegenüber der Außenwandung des Bohrkronenhalses 1.4 teilweise radial überstehen und in ihrer hier dargestellten entriegelnden zweiten Position gegenüber der Außenwandung des Bohrkronenhalses 1.4 nicht radial überstehen.
• Figur 2 zeigt das mit der Bohrkrone 1 zu verbindende Rohr 2, welches an seinem unteren Rand vier Randausnehmungen 2.1 aufweist, welche in ihrer Form und in ihrer Anordnung mit den hier nicht gezeigten Ausformungen 1.1 korrespondieren. Der Außendurchmesser des Rohres 2 ist etwa so groß wie der Außendurchmesser der hier nicht gezeigten Bohrkrone 1. Der Innendurchmesser des Rohres 2 ist geringfügig größer als der Außendurchmesser des Bohrkronenhalses 1.4, so dass dieser in das Rohr 2 mit kleinem Spiel oder spielfrei einsteckbar ist. In der Innenwandung des Rohres 2 sind zwei Vertiefungen 2.2 gegenüberliegend angeordnet, deren Größe und Lage mit Größe und Lage der Verriegelungsbolzen 3 korrespondieren.
• Figur 3 zeigt einen Längsschnitt eines Teils des Rohres 2 sowie der erfindungsgemäßen Bohrkrone 1 in ihrem verriegelten Zustand, also in dem Zustand, in welchem die Bohrkrone 1 derart fest mit dem Rohr 2 verbunden ist, dass dessen Drehbewegung und Vorschub auf die Bohrkrone 1 übertragbar ist, so dass ein Bohrloch herstellbar ist. Die aus Stahl gefertigten Ausformungen 1.1 sind jeweils mittels zweier Schrauben 1.2 mit dem Grundkörper der Bohrkrone 1 verbunden, so dass Ausformungen 1.1 und Bohrkrone 1 mit ihren zylindrischen Außenflächen bündig sind. Die zentrisch angeordnete zylinderförmige Ausnehmung 1.3 weist an ihrem links dargestellten Ende den Konus 1.5 auf, der zur Erleichterung des Einführens eines Mediums dient. Die Darstellung zeigt zwei Verriegelungsbolzen 3, die radial verschieblich und jeweils mittels der Fixierplatte 3.3 im Bohrkronenhals 1.4 befestigt sind. Die Fixierplatten 3.3 stehen gegenüber der Außenwandung des Bohrkronenhalses 1.4 nicht nach außen über. Die Verriegelungsbolzen 3 befinden sich hier in ihrer verriegelnden ersten Position, in der sie gegenüber der Außenwandung des Bohrkronenhalses 1.4 teilweise radial überstehen und in die korrespondierenden innenseitigen Vertiefungen 2.2 des Rohres 2 eingreifen, so dass dieses insbesondere in axialer Richtung gegenüber dem Bohrkronenhals 1.4 und damit gegenüber der Bohrkrone 1 fixiert ist. Jeder Verriegelungsbolzen 3 ist fest mit einer Fußplatte 3.1 verbunden, welche mittels einer vorgespannten Schraubenfeder 3.2 mit einer nach innen, radial auf eine Außenwandung einer Haltehülse 4, gerichteten Druckkraft beaufschlagt ist. Die Haltehülse 4 weist einen Außendurchmesser auf, der geringfügig kleiner ist als der Innendurchmesser der Ausnehmung 1.3. Dadurch ist die der temporären Lagefixierung der Verriegelungsbolzen 3 und derer Fußplatten 3.1 dienende Haltehülse 4 axial verschiebbar.

• Figur 4 zeigt einen Entriegelungsbolzen 5, der in seinem rechts dargestellten vorderen Bereich einen Kragen 5.1 aufweist, dessen Außendurchmesser größer ist als der des zylinderförmigen Grundkörpers des Entriegelungsbolzens 5. Der Außendurchmesser des Kragens 5.1 ist kleiner als der Innendurchmesser der Ausnehmung 1.3 und größer als der Innendurchmesser der Haltehülse 4. Am vorderen Bereich des Entriegelungsbolzens 5 ist eine Ventilkugel 6 mittels einer Ventilfeder 7 gegenüber einem mit dem Entriegelungsbolzen 5 verschraubten Kopf 8 verspannt, so dass ein Rückschlagventil gebildet ist, durch das ein unter ausreichendem Druck stehendes Fluid aus dem Kopf 8 ausströmbar ist, wobei ein Einströmen eines Fluides durch den Kopf 8 in den Entriegelungsbolzen 5 jedoch verhindert ist. Der Entriegelungsbolzen 5 weist an seinem links dargestellten Ende ein Innengewinde auf, mit dem er mit einem eigentlich in den Baugrund einzubauendes Bauteil, beispielsweise ein Manschettenrohr oder ein Vereisungsrohr, verbindbar ist, so dass der Entriegelungsbolzen 5 mit Ventilkugel 6, Ventilfeder 7 und Kopf 8 einen Lanzenkopf für das Manschettenrohr bzw. das Vereisungsrohr bilden kann. Es ist auch möglich, dass der Entriegelungsbolzen 5 an seinem links dargestellten Ende mit einem Außengewinde zum Anschluss an das eigentlich in den Baugrund einzubauende Bauteil versehen ist.
• Figur 5 zeigt eine Schnittdarstellung durch die im Wesentlichen zylinderförmige Haltehülse 4. Die Innenwandung der Haltehülse 4 weist einen über ihre Länge konstanten Innendurchmesser auf. Die Außenwandung der Haltehülse 4 weist einen über ihre Länge veränderlichen Außendurchmesser auf, wobei der Außendurchmesser an den rechts und links gezeigten Rändern der Haltehülse 4 geringfügig größer ist als im mittleren Bereich der Haltehülse 4, dessen Länge etwas größer ist als die axiale Ausdehnung der hier nicht gezeigten Fußplatten 3.1, wodurch die Haltehülse 4 in eingebautem Zustand mittels der unter radialer Federkraft stehenden Fußplatten 3.1 in der in Figur 3 gezeigten verriegelnden Position axial selbstfixiert ist. Dadurch, dass der Außendurchmesser vom links dargestellten Rand der Haltehülse 4 nur allmählich, nämlich unter geringer Neigung von etwa 10°, abnimmt, ist die Haltehülse 4 in ihrem eingebauten Zustand unter Einwirkung einer definierten axial gerichteten Kraft von ihrer verriegelnden Position heraus gegen verschiebbar, wobei die in Figur 3 erläuterten Fußplatten 3.1 gegen die Federkraft der Schraubenfedern 3.2 radial nach außen verschoben werden. Der Außendurchmesser nimmt auch vom rechts dargestellten Rand der Haltehülse 4 nur allmählich, nämlich unter geringer Neigung von etwa 10°, ab. Dadurch ist die Haltehülse 4 spiegelsymmetrisch, wodurch sie in ihrer Einbaulage in beiden möglichen Richtungen in die Bohrkrone gleichwirkend einbaubar ist.
• Figur 6 zeigt einen Längsschnitt einiger Teile der Bohrkrone nach Figur 3, nämlich der Bauteile, die ein Rückschlagventil bilden, das eine ähnliche Wirkungsweise wie das in Figur 4 beschriebene hat. Dabei handelt es sich um eine Distanzplatte 1.6, welche ein Außengewinde zur Befestigung in einem korrespondierenden Innengewinde im Grundkörper der Bohrkrone 1 aufweist, eine Kugel 1.7, eine Ventilfeder 1.8 sowie um eine mit Durchgangsbohrungen versehene, runde Halteplatte 1.9, die rechts zudem in ihrer Ansicht dargestellt ist. Im eingebauten Zustand verhindert das mit den dargestellten Elementen gebildete Rückschlagventil, dass ein Fluid von außen über die Bohrkrone 1 in das Rohr 2 einströmt, wenngleich sichergestellt ist, dass ein unter ausreichendem Druck stehendes Fluid aus der Bohrkrone 1 nach außen austreten kann.
• Figur 7 zeigt einen Längsschnitt eines Teils des Rohres 2 sowie der erfindungsgemäßen Bohrkrone 1 gemäß Figur 3, allerdings in ihrem entriegelten Zustand, also in dem Zustand, in welchem der Entriegelungsbolzen 5 bereits ausreichend tief eingeführt ist, so dass die Bohrkrone 1 zwar einerseits noch drehfest mit dem Rohr 2 verbunden ist, dass dessen Drehbewegung und Vorschub auf die Bohrkrone 1 übertragbar ist, also die Ausformungen 1.1 noch in Wirkverbindung mit den korrespondierenden Randausnehmungen 2.1 stehen, dass aber andererseits die Haltehülse 4 mittels des Kragens 5.1 bereits so weit axial verschoben wurde, dass die Fußplatten 3.1 unter Einwirkung der Federkraft der Schraubenfedern 3.2 radial nach innen gedrückt wurden, dass die Verriegelungsbolzen 3 nicht mehr in die Vertiefungen 2.2 eingreifen. Damit ist die Bohrkrone 1 nicht mehr axial gegenüber dem Rohr 2 gesichert, so dass das Rohr 2 von der Bohrkrone 1 abgezogen werden kann. Damit ist es möglich, das Rohr 2 aus dem Baugrund zu ziehen, so dass nur die Bohrkrone 1 als verlorenes Bauteil im Baugrund verbleibt. Dies ist besonders effektiv, da durch das Einführen des Entriegelungsbolzens 5, an welchem das eigentlich einzubauende Bauteil, welches hier nicht gezeigt ist, befestigt ist, das eigentlich einzubauende Bauteil, beispielsweise ein Manschettenrohr oder ein Vereisungsrohr, bereits eingebaut ist. Das Einführen des Entriegelungsbolzens 5 ist infolge einer Interaktion des Konus 1.5 und des konischen Kopfes 8 besonders einfach und selbstzentrierend erfolgt. Das heißt, dass erfindungsgemäß dann, wenn nach Abschluss der Bohrung nach Erreichen der endgültigen Bohrlochtiefe das eigentlich einzubauende Bauteil, an dessen Spitze der Entriegelungsbolzen 5 angebracht ist, seine vorbestimmte Lage erreicht, die Bohrkrone 1 automatisch vom Rohr 2 gelöst wird. Anschließend kann das Rohr 2 ohne die Bohrkrone 1 aus dem Baugrund gezogen werden, während abgesehen von der Bohrkrone 1 das Manschettenrohr oder das Vereisungsrohr im Baugrund verbleibt. Es ist ebenso möglich, andere auf die erfindungsgemäße Weise eingeführte Einbauten im Baugrund zu belassen, beispielsweise Gewi-Stähle.

Corresponding parts are provided in all figures with the same reference numerals.

• FIG. 1 shows a perspective, schematic representation of a drill bit 1 according to the invention, which is to be used for producing a vertical wellbore in a subsoil, not shown. The drill bit 1 has at its lower end on a cylindrical outer wall, protrude from the four formations 1.1 upwards, but with respect to the cylindrical outer wall at the lower end of the drill bit 1 does not protrude to the outside. The formations 1.1 are each separate elements, each secured with a screw 1.2 in the main body of the drill bit 1. The drill bit 1 is formed in its upper region by the arrangement of a recess 1.3 a hollow cylinder, which is located within a Bohrkronenhalses 1.4 and at its upper edge has a cone 1.5. The drill bit 1 is the non-rotatable connection to a not shown here and in the Figures 2 . 3 and 7 represented pipe 2. In the Bohrkronenhals 1.4 two locking bolts 3 are arranged, which are radially displaceable and each fixed by means of a fixing plate 3.3 in the drill bit neck 1.4. The fixing plates 3.3 are not opposite to the outer wall of the Bohrkronenhalses 1.4 to the outside. The locking bolts 3 are radially displaceable, from a locking first position to an unlocking second position, wherein they protrude in their not shown here locking first position relative to the outer wall of the Bohrkronenhalses 1.4 partially radially and in their here shown unlocking the second position relative to the outer wall of the Bohrkronenhalses 1.4 not radially projecting.
• FIG. 2 shows the pipe to be connected to the drill bit 1 2, which has four edge recesses 2.1 at its lower edge, which correspond in shape and in their arrangement with the formations 1.1, not shown here. The outer diameter of the tube 2 is about as large as the outer diameter of the drill bit 1, not shown here. The inner diameter of the tube 2 is slightly larger than the outer diameter of the Bohrkronenhalses 1.4, so that it can be inserted into the tube 2 with little play or clearance. In the inner wall of the tube 2, two recesses 2.2 are arranged opposite each other, whose size and position correspond to the size and position of the locking bolt 3.
• FIG. 3 shows a longitudinal section of a portion of the tube 2 and the drill bit 1 according to the invention in its locked state, ie in the state in which the drill bit 1 is so firmly connected to the tube 2, that its rotational movement and feed to the drill bit 1 is transferable, so that a borehole can be produced. The moldings 1.1 made of steel are each connected by means of two screws 1.2 with the main body of the drill bit 1, so that formations 1.1 and drill bit 1 are flush with their cylindrical outer surfaces. The centrally arranged cylindrical recess 1.3 has at its end shown on the left the cone 1.5, which serves to facilitate the insertion of a medium. The illustration shows two locking bolts 3, which are radially displaceable and in each case fixed by means of the fixing plate 3.3 in the drill bit neck 1.4. The fixing plates 3.3 are not opposite to the outer wall of the Bohrkronenhalses 1.4 to the outside. The locking pins 3 are here in their locking first position, in which they protrude over the outer wall of the Bohrkronenhalses 1.4 partially radially and engage in the corresponding inside recesses 2.2 of the tube 2, so that this in particular in the axial direction relative to the Bohrkronenhals 1.4 and thus the drill bit 1 is fixed. Everyone Locking bolt 3 is fixedly connected to a base plate 3.1, which is acted upon by means of a prestressed coil spring 3.2 with an inwardly, radially on an outer wall of a retaining sleeve 4, directed pressure force. The holding sleeve 4 has an outer diameter which is slightly smaller than the inner diameter of the recess 1.3. As a result, the temporary fixing of the position of the locking bolt 3 and those foot plates 3.1 serving retaining sleeve 4 is axially displaceable.

• FIG. 4 shows an unlocking pin 5, which has a collar 5.1 in its front area shown on the right, whose outer diameter is larger than that of the cylindrical base body of the unlocking pin 5. The outer diameter of the collar 5.1 is smaller than the inner diameter of the recess 1.3 and larger than the inner diameter of the retaining sleeve 4. At the front region of the unlocking bolt 5, a valve ball 6 is clamped by means of a valve spring 7 against a bolted to the unlocking bolt 5 head 8, so that a check valve is formed, through which a standing under sufficient pressure fluid from the head 8 can be flowed out However, a flow of a fluid through the head 8 in the unlocking bolt 5 is prevented. The unlocking pin 5 has at its end shown on the left an internal thread, with which it can be connected to an actually be built into the ground component, such as a sleeve pipe or icing, so that the unlocking pin 5 with valve ball 6, valve spring 7 and head 8 a Lance head for the sleeve tube or the icing tube can form. It is also possible that the unlocking pin 5 is provided at its end shown on the left with an external thread for connection to the actually to be built into the ground component.
• FIG. 5 shows a sectional view through the substantially cylindrical holding sleeve 4. The inner wall of the holding sleeve 4 has a constant over its length inner diameter. The outer wall of the holding sleeve 4 has a variable over its length outer diameter, wherein the outer diameter at the edges of the holding sleeve 4 shown on the right and left is slightly larger than in the central region of the holding sleeve 4, whose length is slightly larger than the axial extent of the foot plates 3.1, not shown here, whereby the holding sleeve 4 in the installed state by means of the standing under radial spring force foot plates 3.1 in the in FIG. 3 shown locking position axially self-fixed. Due to the fact that the outer diameter decreases from the edge of the retaining sleeve 4 shown on the left only gradually, namely at a low inclination of approximately 10 °, the retaining sleeve 4 is displaceable in its installed state under the action of a defined axially directed force from its locking position, wherein in the FIG. 3 explained foot plates 3.1 are moved against the spring force of the coil springs 3.2 radially outward. The outer diameter decreases from the edge of the retaining sleeve 4 shown on the right only gradually, namely at a low inclination of about 10 ° from. As a result, the holding sleeve 4 is mirror-symmetrical, whereby it can be installed with equal effect in its installation position in both possible directions in the drill bit.
• FIG. 6 shows a longitudinal section of some parts of the drill bit after FIG. 3 , namely the components that form a check valve, which has a similar operation as in FIG. 4 has described. It is a spacer plate 1.6, which has an external thread for attachment in a corresponding internal thread in the main body of the drill bit 1, a ball 1.7, a valve spring 1.8 and a provided with through holes, round support plate 1.9, the right also shown in their view is. When installed, the non-return valve formed with the illustrated elements prevents fluid from entering the tube 2 from outside via the drill bit 1, although it is ensured that a fluid under sufficient pressure can escape from the drill bit 1 to the outside.
• FIG. 7 shows a longitudinal section of a portion of the tube 2 and the drill bit 1 according to the invention according to FIG. 3 , However, in its unlocked state, ie in the state in which the unlocking bolt 5 is already introduced sufficiently deep, so that the drill bit 1 on the one hand still rotatably with the Tube 2 is connected, that its rotational movement and feed to the drill bit 1 is transferable, so that the formations are 1.1 still in operative connection with the corresponding Randausnehmungen 2.1, but that on the other hand, the retaining sleeve 4 has been moved so far axially by means of the collar 5.1 that the Foot plates 3.1 were pressed radially inwardly under the action of the spring force of the coil springs 3.2, that the locking pin 3 no longer engage in the recesses 2.2. Thus, the drill bit 1 is no longer axially secured against the tube 2, so that the tube 2 can be deducted from the drill bit 1. This makes it possible to pull the tube 2 out of the ground, so that only the drill bit 1 remains as a lost component in the ground. This is particularly effective, since the insertion of the unlocking pin 5, to which the component actually to be installed, which is not shown here, is attached, the component actually to be installed, for example a sleeve tube or a freezing tube, is already installed. The insertion of the unlocking bolt 5 is particularly simple and self-centering due to an interaction of the cone 1.5 and the conical head 8. That is, according to the invention, when, after completion of the drilling after reaching the final hole depth, the actual component to be installed, at the top of the unlocking pin 5 is attached, reaches its predetermined position, the drill bit 1 is automatically released from the tube 2. Subsequently, the tube 2 can be pulled without the drill bit 1 from the ground, while apart from the drill bit 1, the sleeve tube or the icing tube remains in the ground. It is also possible to leave other internals introduced in the manner according to the invention in the ground, for example Gewi steels.

LIST OF REFERENCE NUMBERS

1

drill bit
1.1 formation
1.2 screw
1.3 recess
1.4 drill bit neck
1.5 cone
1.6 Distance plate
1.7 ball
1.8 valve spring
1.9 retaining plate

2

pipe
2.1 Randausnehmung
2.2 deepening

3

locking bolt
3.1 foot plate
3.2 coil spring
3.3 Fixing plate

4

holding sleeve

5

unlocking
5.1 collar

6

valve ball

7

valve spring

8th

head

Claims (15)

Drill bit (1) for drilling a subsoil,
characterized by means for internally releasing a releasable connection between the drill bit (1) and a tube (2). Drill bit (1) according to claim 1,
characterized by a recess (1.3) into which an unlocking bolt (5) for triggering the means for releasing is insertable. Drill bit (1) according to claim 1 or 2,
characterized in that the means for releasing the releasable connection between the drill bit (1) and the tube (2) comprises a number of radially displaceable locking pins (3) displaceable from a locking first position to an unlocking second position. Drill bit (1) according to claim 3,
characterized in that the number of locking bolts (3) in its locking first position relative to an outer wall of a Bohrkronenhalses (1.4) at least partially projects radially and in its unlocking second position relative to the outer wall of the Bohrkronenhalses (1.4) does not project radially. Drill bit (1) according to one of the preceding claims,
characterized in that the means for releasing the releasable connection between the drill bit (1) and the tube (2) comprises a triggering of the unlocking causing holding sleeve (4) which is arranged in the recess (1.3). Drill bit (1) according to the preceding claim,
characterized in that the holding sleeve (4) for triggering the unlocking is axially displaceable between the locking first position and the unlocking second position. Drill bit (1) according to one of the preceding claims, characterized
marked that
the number of radially displaceable locking bolts (3) is biased by spring force such that it is displaceable upon release from a locking first position to an unlocking second position. Drill bit (1) according to claim 7, characterized in that each locking bolt (3) is biased by a helical spring. Drill bit (1) according to one of the preceding claims, characterized
marked that
at the Bohrkronenhals (1.4) a number of formations (1.1) is arranged, which is axially inserted into a number of corresponding Randausnehmungen (2.1) of the tube (2). Drill bit (1) according to one of claims 2 to 9, characterized in that
the recess (1.3) is provided with a cone (1.5) for simplified insertion of the unlocking pin (5). Method for releasing a drill bit (1) for drilling a ground from a pipe (2) in a sunk state, in particular for releasing a drill bit (1) according to one of the preceding claims from a pipe (2), wherein a connection between the drill bit (1 ) and a tube (2) is loosened internally. Method according to claim 11,
characterized in that a release of the drill bit (1) triggering release bolt (5) in a in the drill bit (1) arranged, centric, cylindrical recess (1.3) is introduced. Method according to claim 12,
characterized in that the unlocking pin (5) has a collar (5.1) whose outer diameter is greater than the inner diameter of the retaining sleeve (4) and whose inner diameter is smaller than the inner diameter of the retaining sleeve (4) and
in that by inserting the unlocking bolt (5) into the recess (1.3), a retaining sleeve (4) arranged therein is displaced axially from a locking first position into an unlocking second position for triggering the unlocking. Method according to claim 13,
characterized in that by the axial displacement of the holding sleeve (4) from the locking first position to the unlocking second position a number of radially displaceable and biased locking bolts (3) are unlocked, whereby the locking bolts (3) from a locking first position Move to an unlocking second position. Method according to claim 14,
characterized in that the number of locking bolts (3) in its locking first position with respect to an outer wall of a Bohrkronenhalses (1.4) at least partially survive radially and in its unlocking second position relative to the outer wall of the Bohrkronenhalses (1.4) does not project radially.

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