EP2483522B1 - Boring element of a ground boring device - Google Patents

Description

The invention relates to a drilling element of a Erdbohrvorrichtung with a housing and arranged in a receptacle of the housing transmitter.

It is known to provide earth boring devices with a transmitter for locating the signals emitted by the transmitter by means of a receiving unit located at the surface of the earth, thereby determining the position of the earth boring device within the soil. This makes it possible to continuously check the course of the bore and - if it is a controllable Erdbohrvorrichtung - to correct the bore course by a reversal of the Erdbohrvorrichtung in a deviation from the desired course.

In the prior art, various embodiments of controllable Erdbohrvorrichtungen known. For the introduction of horizontal wells in the ground, that is, such holes, which extend substantially in shallow layers of soil in the horizontal direction, so-called ground rockets are often used. These are self-propelled impact drills, which are equipped with a percussion driven air-operated unit and are supplied with the required compressed air supply via a rear supply hose. A controllability of such Erdrakete can be achieved for example by an adjustment of the drill head tip, whereby a lateral deflection is generated, which leads to an arcuate Bohrverlauf. Such a controllable Erdrakete is for example in the DE 199 47 645 C1 disclosed.

Furthermore, HorizontalDbohrvorrichtungen are known in which a front of a drill pipe arranged drill head is propelled by means of a arranged in a pit, a shaft or on the earth's surface driving and rotating rotating through the soil. A controllability in such a horizontal drilling device is achieved in that the drill head is formed asymmetrically, for example with an oblique face, so that in a purely sliding, i. non-rotating driving of the drill head, a lateral force is generated, which leads to the desired lateral deflection of the drill head. For straightforward drilling, this lateral force is compensated on average by additionally driving the drill head in a uniformly rotating manner.

Even with such a rod-based horizontal drilling device can be provided to assist the Bohrvortrieb the drill head by exerting blows. This can be done - as in a Erdrakete - by internal Schlagwerk; However, it is regularly provided to have the blows generated by an external impact mechanism and to transmit these to the drill head via the drill string. This can avoid having to integrate a hammer mechanism in the often limited in size drill head.

A drill head for such a rod-based horizontal drilling device is for example in the DE 195 34 806 A1 disclosed. This includes a designated as a steering head inclined drilling head and an adjoining housing, in which a receptacle is provided for a transmitter. At the opposite end of the oblique drill head, the housing is provided with an external thread, with which this can be screwed to a first rod section of the drill string. The transmitter is movably mounted within the receptacle of the cylindrical housing in its longitudinal axial direction and abuts with its two ends to a respective buffer, which serve to the generated by the exertion of the blows on the drill string relative movement of the transmitter within the receptacle of the housing dampen. In this way, the amount of force pulses acting on the transmitter, can be significantly reduced, which is necessary insofar as it is regularly in such a transmitter is a sensitive electronic component.

A structurally similar integration of a transmitter in an earth rocket is for example from the DE 198 23 629 A1 known. It is intended to retrofit an earth rocket with a drill head, in which the transmitter is integrated. There is also provided to embed the transmitter in the corresponding receptacle in the drill bit of Bohrkopfaufsatzes end between two damping elements.

It has been found in prior art earth boring devices with integrated transmitters that it is not always possible to achieve a sufficient reduction of the impact load of the transmitters and that these are consequently damaged by the operation of the striking earth boring device.

EP 0 759 498 A2 discloses an arrangement of a shock sensitive transmitter in a drilling rig. The transmitter is held by means of at least one shock-absorbing buffer at least in the main direction of impact with distance from the wall of a chamber in the drill. The transmitter occupies a defined position relative to a housing, which does not change during operation.

EP 0 361 805 A1 discloses an earth boring device in which a probe is provided for locating the earth boring device. The probe is placed firmly between two shock-absorbing buffers.

DE 199 10 292 A1 discloses a method and apparatus for steering a ram boring machine. The ram boring device comprises a device housing, inside which there is a sensor which forms a structural unit with a transmitter. The assembly of sensor and transmitter is fixedly mounted with its front end via a Torsionssicherung with a connecting pin to a damping tube and a damping buffer in the device housing.

EP 0 617 193 A1 discloses a ram boring machine with a transmitter that can be protected by suitable damping elements against axial or radial vibrations and shocks. In Rammbohrgerät a bore is formed, which serves to receive the transmitter, which can be protected by suitable damping elements both in the axial and in the radial direction against vibrations and shocks. The transmitter is thus embedded in damping elements.

WO 02/35049 A1 discloses a steerable ground rocket equipped with a probe and roll sensors, the probe being firmly embedded in a chamber via buffers against the impact of the propulsion unit of the ground rocket.

Based on this prior art, the invention therefore an object of the invention to provide an improved integration of a transmitter in a Erdbohrvorrichtung.

This object is solved by the subject matter of the independent claim. Advantageous embodiments are the subject of the dependent claims and will become apparent from the following description of the invention.

The essence of the invention lies in further reducing the height of the forces transmitted to the transmitter from a housing of the earth boring device into which the transmitter is integrated, in that the latter is suspended in an exclusively elastic-damping manner by pulling. This is achieved in that the transmitter is connected within a receptacle of a housing of a drilling element of a Erdbohrvorrichtung in which it is movably mounted in the longitudinal axial direction (of the drilling element) via a front-side buffer to the housing, that the transmitter in a rear impact on the drilling element undergoes a backward displacement in the receptacle, made possible by a deformation of the buffer, without this striking directly against an element of the drilling element.

It has been found that an attenuation of the impact pulses that is better than the two-sided embedding known from the prior art in two damper elements can be achieved by an exclusively pulling elastic-damping suspension of the transmitter in the housing of the drilling element.

A "drilling element" of an earth boring device can be any component of an earth boring device into which a transmitter can be integrated.

A "buffer" is a component that transforms the kinetic energy of a connected component (in this case the transmitter) by deformation, thereby reducing the amount of transmitted forces. According to the invention, a buffer can be designed exclusively as a spring element and also exclusively as a damping element. Preferably, however, a buffer according to the invention is a combined spring-damper element.

The term "front side" or "forward" is understood according to the invention to mean a location that is different from the respective element in the direction of the drill front and consequently
extends the front of the Erdbohrvorrichtung. Accordingly, "backward" or "backwards" refers to a direction that extends from the drilling front or the front of the earth boring device in the direction of the already created bore.

In a preferred embodiment of the drilling element according to the invention this is designed as a drill head. It can thereby be achieved that the transmitter, which is arranged in a receptacle of the housing of the drilling element, is arranged as far as possible at the front end of the Erdbohrvorrichtung, whereby the positioning accuracy can be improved.

In a further preferred embodiment of the drilling element according to the invention can be provided to provide an additional back buffer, which is arranged so that the transmitter deforms this only after a defined backward displacement in the receptacle (which can be very small). The back buffer may then be used, for example. act by damping a damping when unexpectedly high impact forces are exerted on the drilling element, which lead to a correspondingly high displacement of the transmitter in the recording.

The drilling element according to the invention may further comprise an integrated into the drilling element power supply for the transmitter. This can prevent the transmitter from having to be connected to an external power supply via an electrically conductive connection. Such a connection to an external power supply has frequently been found to be susceptible to interference in the earth boring devices known from the prior art. An integrated power supply for the transmitter can preferably be done via batteries, with other possibilities for power supply are possible. For example, a turbine driven by a drilling fluid or by compressed air may be connected to a generator which generates the corresponding energy for the operation of the transmitter.

Advantageously, it can be provided that the receptacle in the housing of the drilling element is accessible from the outside, so that the transmitter and possibly also the power supply can be used and replaced again without having to disassemble the auger itself. The opening required for accessibility in the housing of the drilling element is preferably closable by means of a closure element. Preferably, the closure element is easily fixable and detachable, whereby maintenance work on the transmitter and the preferably provided integrated power supply can be simplified.

In a particularly preferred embodiment can be provided to form the receptacle as a front hole in the drilling element. This can be avoided be that an opening in the shell of the drilling element must be introduced.

In such a front bore for receiving the transmitter, a sealing plug may preferably be provided as a closure element, which is further preferably held by clamping in the bore. This can be done for example by means of a conical sealing plug, which in turn is held in a corresponding conical receiving the bore. The reaction forces of the soil acting on the sealing plug during drilling press on the sealing plug, which is thus pressed into the bore; the clamping fixation of the drilling plug in the bore is thereby supported.

In a further preferred embodiment it can be provided that at least the closure element, the buffer and the transmitter are connected to each other, so that they can be introduced as a transmitter unit in the drilling element and also removed from this again. As a result, the assembly and disassembly of the transmitter unit is considerably simplified during maintenance. If an integrated power supply and / or a back buffer are provided, these may preferably also be integrated in the transmitter unit.

The invention will be explained in more detail with reference to embodiments shown in the drawings.

Fig. 1:

einen erfindungsgemäßen Bohrkopf in einer isometrischen Ansicht; und

Fig. 2:

den Bohrkopf der Fig. 1 in einer geschnittenen Zeitenansicht.

In the drawings shows

Fig. 1 :

a drill head according to the invention in an isometric view; and

Fig. 2 :

the drill head of Fig. 1 in a cut times view.

In the Fig. 1 and 2 an inventive drill head is shown in a first embodiment. This drill head is intended to be used as part of an earth rocket, including this with a housing of the Erdrakete (not shown) is screwed.

The drill head comprises a cylindrical housing 1, which is designed in two parts, wherein the two housing parts are displaceable in the longitudinal axial direction over a certain distance from each other. For this purpose, a front housing part 2 is displaceably mounted on a rear housing part 3, wherein this bearing is sealed by a sealing ring 4. Through the rear housing part 3 and a portion of the front housing part 2, a piston 5, which is connected via a total of four transverse pins 6, which can be inserted through corresponding openings in the housing, with the front housing part 2 extends. The bearing of the piston 5 within the rear Housing part 3 is also designed to be displaceable in the longitudinal axial direction, wherein the rear housing part 3 and the piston 5 are supported by a cylindrical coil spring 7 against each other.

The rear housing part further has an external thread 8, with which the drill head can be screwed into a corresponding internal thread of the Erdraketengehäuses.

In the mounted state of the drill head, the free end of the piston 5 projects into a striking space of the earth rocket, in which a percussion piston driven in a known manner by means of compressed air is driven in a cyclical back-and-forth motion. The forward stroke of the percussion piston is thereby slowed down and terminated, that this impinges on the free end of the piston 5 and accelerates it in the direction forward. This acceleration of the piston 5 is transmitted directly to the front housing part 2 of the drill head, whereby this creates the hole step by step. After a defined forward movement of the piston 5 this meets with an annular projection 9 on a rear end of the second housing part 3, whereby the remaining kinetic energy of the piston 5 is transmitted to the second housing part 3 of the drill head and the associated Erdraketengehäuse. Accordingly, after the front housing part 2 of the drill head has driven the bore, the Erdraketengehäuse tightened.

The front housing part 2 of the drill head consists of a first, designated as a drill mandrel portion 10, which has a substantially constant outer diameter. This is followed by a conical widening section 11 formed in a stepped shape, which serves to widen the borehole 10 predrilled bore to the desired diameter. The drill mandrel 10 is hollow and thus forms a receptacle for a transmitter 12, by means of which the drill head can be located by means of a arranged on the earth surface receiving unit (not shown). The transmitter 12, which likewise has a cylindrical shape, is in principle mounted slidably in the receptacle in the longitudinal axial direction (of the drill head and of the transmitter 12), for which purpose a guide bush 13 is integrated into the drill mandrel 10 whose material is chosen such that it on the one hand causes no or only a small shielding of the signals emitted by the transmitter 12 and on the other hand has only a small coefficient of friction with the material of the transmitter 12. The transmitter 12 is connected via a fixing sleeve 14 with a front buffer 15. This is also movably mounted in a portion of the receptacle within the drill mandrel 10. On the opposite end of the fixing sleeve 14 of the front-side buffer 15, this is connected to a sealing plug 16, which closes the front opening of the drill mandrel 10.

The impact forces transmitted by the percussion piston of the rocket to the piston 5, from there to the front housing part 2 of the drill head and from there to the closure plug 16 are transmitted further to the transmitter 12 via the front buffer 16 and the fixing sleeve 14, these being tensile forces to act on this; this is thus pulled pulling. The amount of these tensile forces is reduced by the fact that the front-side buffer 15 is deformed under the action of the forward-acting impact forces and the inertial forces of the transmitter 12 and partially converts these into potential forces and into heat. As a result, force peaks can be prevented, which could lead to damage to the transmitter 12.

The drill head according to the invention is further provided with a rear buffer 17, which is arranged in the unloaded state of the drill head in a defined, albeit very small distance from the rear end of the transmitter 12. In the exercise of impact forces on the piston 5 of the drill head, therefore, there is initially a relative displacement of the transmitter 12 in the guide sleeve 13, which is due to a deformation of the front-side buffer 15, without directly leading to an additional damping deformation of the back buffer 17th comes. The rear buffer 17 serves, in the event of particularly high impact forces, additionally dampening the relative movement of the transmitter 12 in the guide sleeve 13.

Within the fixing sleeve 14 is still a battery 18, which serves as an internal power supply for the transmitter. This is on the one hand via a first cylindrical coil spring 19 to the transmitter 12 and on the other hand - also via a second cylindrical coil spring 20 and an additional battery buffer 21 - supported on the existing of an electrically conductive material fixing sleeve 14. The cylindrical coil springs 19, 20 serve as additional buffer elements and also as contact elements, by which a circuit is formed by incorporating the electrically conductive fixing sleeve 14.

The sealing plug 16, the front buffer 15, the fixing sleeve 14 and the transmitter 12 are connected to each other so that they can be used as a transmitter unit through the front opening in the receptacle of the drill mandrel 10 and removed again. The integrated between the Fixerhülse 14 and the transmitter 12 power supply is also part of the transmitter unit.

The sealing plug 16 is formed with a (in the installed state in the rearward direction) conically tapered portion which is inserted into a correspondingly conically widening portion of the receptacle of the drill mandrel. This connection between the sealing plug 16 and the reaming mandrel 10 leads to a clamping connection between these two elements, by the of the Soil is reinforced on the front side of the stopper 16 acting resistance forces. An unwanted loosening of the sealing plug 16 and the associated elements of the transmitter unit can be avoided. An unintentional loosening of the sealing plug (eg during handling prior to introduction into the soil) can additionally be effected by a (not shown) dowel pin, which is introduced into a transverse bore 22, which passes through the sealing plug 16 and the front portion of the drill mandrel 10 , A loosening of the sealing plug 16 can be effected by means of a tool which engages in the groove formed between the sealing plug 16 and the annular end face of the drill mandrel 10.

In the area of the transmitter, the drill mandrel is provided with a total of four longitudinal openings 23, which are filled with a plastic, which is characterized in that it does not or only weakly shield the signals emitted by the transmitter. This plastic filling prevents clogging of the longitudinal openings 23 with soil.

Claims (8)

1. Drilling element of an earth drilling device with a casing (1) and a transmitter (12) arranged in a receptacle in the casing (1), wherein the transmitter (12) is moveably mounted in the receptacle in the longitudinal axial direction of the drilling element and is connected with the casing (1) via a front-side buffer (15), characterised in that the transmitter (12) is suspended by means of the front-side buffer (15) in an elastically dampened pulling way, so that the transmitter (12) is subjected to a rearward directed displacement in the receptacle by a rearward impact impulse onto the casing (1) that is made possible by a deformation of front-side buffer (15), without the same directly hitting a further element.
2. Drilling element according to claim 1, characterised in that this is designed as a drill head.
3. Drilling element according to one of the preceding claims, characterised by a rear-side buffer (17) that is deformed by the transmitter (12) only after a defined rearward directed displacement of the transmitter (12) in the receptacle.
4. Drilling element according to one of the preceding claims, characterised by an energy supply for the transmitter (12), integrated into the drilling element.
5. Drilling element according to one of the preceding claims, characterised in that the receptacle is accessible from the outside and can be closed with a closure element.
6. Drilling element according to claim 5, characterised in that the receptacle is designed as a front-side bore in the drilling element.
7. Drilling element according to claim 6, characterised in that the closure element is designed as a sealing plug (16) held clamped in the bore.
8. Drilling element according to one of the claims 5 to 7, characterised in that at least the closure element, the front-side buffer (15) and the transmitter (12) are connected with each other.

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