EP1769131B1 - Drill head for a ground-boring device - Google Patents

Abstract

The invention relates to a drill head for a ground-boring device that displaces earth on impact. Said drill head comprises at least three drill head sections (3, 4, 11). The first drill head section is provided with a shape that is optimized for loosening and guiding the device while the second section is optimized regarding radial displacement of the ground at a low resistance to movement and the third section is provided with a fixed connection to the housing of the ground-boring device. In order to obtain improved transmission of advancing forces to the ground and thus improved advancement of the ground-boring device, at least two of the drill head sections are embodied so as to be movable relative to each other along the longitudinal axis thereof.

Description

The invention relates to a drill head for an earth boring device.

For generating wells in the field of horizontal drilling, it is known to use so-called ground rockets, which have a controlled via a drive fluid reciprocating percussion piston. This piston transmits its kinetic energy when hitting a contact surface of the housing or the drill head and drives the auger gradually through the soil.

The drill head of the device fulfills several tasks. On the one hand this transmits the impact energy of the percussion piston on the ground in front of it and loosens this. Furthermore, the loosened soil should be displaced laterally, so that a borehole with the desired diameter is formed. In addition, the drill head to provide a special shape for a guide and thus for a directional stability of the device.

To fulfill these tasks, various drill head shapes have been developed.

On the one hand, drilling heads with a conical base body are known from the prior art (for example DE 21 57 259 C or even out DE 40 14 775 C1 ). These are characterized by the fact that the smoothest, conical jacket has a minimum resistance against the direction of movement.

Some of the conical drill heads on recesses in the direction of the longitudinal axis of the device. Through these depressions, the loosened soil is transported to the outside.

As a disadvantage, these drill heads show a low directional stability, so that the device is deflected out of the desired path by lateral forces, which are caused by hitting obstacles or inhomogeneities within the ground.

In addition to the conical drill heads, the so-called step heads are known (for example DE 101 12 985 A1 ). The step heads also have a diameter which increases starting from the tip, but the increase in diameter occurs in steps, Im Longitudinal section shows a drill head of this type thus two stairs that meet in the top of the head. By dividing the lateral surface into a plurality of sections which run either (almost) parallel or perpendicular to the longitudinal axis of the device, only slight side forces occur on the drill head, so that step heads have good directional stability. The disadvantage is that a high movement resistance in the advancing direction is created by the step surfaces located perpendicular to the longitudinal axis. This results in a correspondingly reduced propulsion speed

Furthermore, it is off DE 101 12 985 A1 known to allow the drill head or a plurality of elements of the drill head against each other to achieve a more targeted introduction of the available impact energy.

Furthermore, it is off DE 29 17 292 A1 a rock-destroying tool for impact machines known, the drill head consists in the front of a series sternformig arranged cutting. The spaces between the cutting serve as Abführkanale for the removed rock. Behind the cutting edges of the drill head, a conical section of the drill joins, which deflects the removed rock in the direction of the borehole wall, where it is blown through an annular gap between the borehole wall and device housing.

The U.S. Patent 5,467,831 , which is provided as the closest prior art discloses a ram boring device with a koniaehieutaufenden Bohrkopt, at the rear end two stabilizers arranged with a triangular cross section on the housing of the drill head, that in the longitudinal direction of the ram boring aligned channels for the supply and discharge be formed by compressed air.

Based on this prior art, the present invention seeks to provide a particularly advantageous for use in displaceable soil drill head, the particular advantages of the conical drill head - for example, low resistance to movement - with advantages of the step head - for example, high directional stability - connects.

This object is achieved by the subject matter of the independent claims. Advantageous embodiments are claimed in the subclaims.

The invention provides to carry out the drill head from at least three drill head sections.

The first drill head section closest to the front end of the device has discharge channels and can be used to loosen the soil or smash obstacles. The loosened or crushed soil can be guided through the discharge channels in the first drill head portion to the rear in the direction of the second head portion and depending on the version also to the outside.

The term "drill head" in the sense of the invention is to be understood in particular as meaning the tool at the head end of an earth boring device, which can serve for producing and widening bores and already laid lines.

By "discharge channels" are depressions or recessed portions or holes understood that do not extend transversely to the longitudinal direction of the Erdbohrgeräts. The terms "recess" and "hole" are not manufacturing technology limiting, but to understand geometric, so that wells or holes according to the invention can also be produced by cultivation.

It is particularly advantageous if the discharge channels, depending on the design of the Erdbohrgeräts, are arranged at an angle between 0 ° and 45 ° to the longitudinal direction of the Erdbohrgeräts.

The second drill head section with one or more substantially conical sections on the lateral surface can provide for the radial compaction of the loosened soil. The effect of the invention can also be achieved with any other geometries.

In this case, a largely conical shape is understood in particular to mean a lateral surface which-at least partially-rises continuously from a small radial extent to a larger radial extent and thus has no sections within the conical region in which the radius is reduced again.

The third drill head section is designed for attachment of the entire drill head to the housing of an earth boring device. This attachment to the housing may be direct or indirect, i. be executed via intermediate elements.

The subdivision of the drill head into the various sections is in particular to be seen functionally, so that it is not necessary that a structural separation of all sections must be given in each embodiment of the invention.

A particular advantage of the drill head according to the invention is that the loosening work or the work of fragmentation is first carried out by a leading drill head section whose shape has been optimized for this task. The preferred combination of the chisel tip with star-shaped blades ensures a high fragmentation performance of the first head section with low resistance to movement. Due to the absence of large, oblique (not vertical) to Moving direction of lying surfaces of the response of the first drill head section on isolated lateral forces due to one-sided obstacles low.

The second drill head section compacts the loosened and shattered soil which has been passed through the depressions behind the first head section. Due to the largely conical shape (of sections) of the second head section this is particularly well designed for the radial displacement of the soil with low resistance to movement.

Such a drill head is now used according to the invention for displacement bores in corresponding displaceable soils. In particular, this can be advantageous when creating horizontal bores.

"Displacement bore" according to the invention is understood to mean a bore which is essentially based on producing a borehole by radially displacing the environment, whereby the corresponding "displaceable bottom" deforms substantially plastically and the soil structure is substantially deformed by adhesion or other physical effects the deformed structure remains.

The formimmanente disadvantage of this head shape, the high sensitivity to unilateral force application, which does not apply in rock drilling, is largely compensated by the fact that the first head portion may have already destroyed obstacles and further characterized in that the second drill head section exclusively by the first section given direction follows.

In order to achieve a targeted transmission of the impact energy of Erdbohrgeräts on the soil, it can be provided according to the invention that at least two of the drill head sections are longitudinally axially movable (relative to the longitudinal axis of the Erdbohrgeräts) to each other.

An advantageous embodiment provides to perform the first and second drill head portion to each other movable. Here, it is preferably provided to execute the second drill head section fixedly - at least longitudinally - to the third drill head section. This can be achieved that first the first head section is driven into the soil. The soil is loosened or smashed and directed backwards. The then driven second head section compresses the loosened soil and thus creates the desired diameter of the borehole. At the same time this is entrained by the fixed connection with the third drill head section or with the housing of Erdbohrvorrichtung.

A particular advantage of this embodiment is that, as the first drill head section is propelled, the housing and the second and third head sections are not initially accelerated, so much of the kinetic energy of the percussion piston is transmitted to crush and loosen the soil.

An alternative embodiment may provide for rigidly connecting the first and second bit sections (at least longitudinally) and for providing that unit movable with the third bit section. In this case, the functions of the first head section - in particular the loosening, shattering and diverting of the soil - and those of the second head section - in particular the radial compression of the loosened soil - are carried out in a joint operation. For this purpose, the entire, transmitted by the percussion piston of the Erdbohrgeräts energy can be used. The tracking of the auger per se is then only in a second step, when the third connected to the housing Bohrkopfabschnitt is propelled.

Furthermore, it may be advantageous to perform all three drill head sections longitudinally axially movable relative to each other. The fact that the three head sections are driven one after the other, an even more targeted initiation of the impact forces of Erdbohrgeräts can be achieved in the soil.

The targeted introduction of the drive energy into the soil in drill heads according to the invention with mutually movable drill head sections are also suitable for use in any soil.

It is advantageous if the discharge channels of the first drill head section are dimensioned so that a large number of equally spaced cutting edges are formed with a small wall thickness. The thin cutting edges ensure a high cutting action, while a generous dimensioning of the discharge channels ensures a low-resistance removal of the soil.

Preferably, the leading edges of the blades (in the advancing direction of the auger) are oriented substantially perpendicular to the longitudinal axis of the drill bit. As a result, side forces as a result of hitting an obstacle, which would cause the drilling device to deviate from the desired direction, can be avoided.

For the purposes of the invention, it is not necessary for the discharge channels to run constantly from the front of the first drill head section to the rear side thereof. Rather, the discharge channels within the first drill head portion may leak or the first drill head portion may consist of two halves, both of which are provided with Abführkanälen or cutting, but are rotationally offset from one another. Thus, a cutting edge of the rear half can be arranged behind each discharge channel of the front half of the first drill head section.

In this way, solids that have not been smashed by the front half meet the edges of the back half.

Furthermore, it may be advantageous if the diameter of the first drill head section substantially corresponds to the diameter of a subsequent housing of the drill. It can thus be achieved that the soil is loosened up by the cutting edges of the first drill head section in a cross-section which substantially corresponds to that of the housing of the drill. In general, the housing diameter and thus the loosened diameter corresponds to the nominal diameter of the bore to be created.

In particular, the drill head sections may be dimensioned such that the largest diameter of the first drill head section is greater than the smallest diameter of the second drill head section. By this diameter jump, as well as by the optional relative movement of the two head sections to each other, between them creates a relaxation space in which the loosened soil can initially relax within limits again.

Furthermore, it may be advantageous to make the largest diameter of the first drill head portion larger than that of the housing. This ensures that a sufficient volume within the soil is relaxed and thus the resistance to movement acting on the housing is reduced.

The first head portion may include or be connected to a striker. The firing pin in turn may have a projecting into the ground chisel tip through which a targeted introduction of the impact energy can be done in the soil located in front of the drill head. In particular, by the point-like application of force that takes place in this way Obstacles, such as stones in the ground, are easily smashed.

In an advantageous embodiment, the firing pin penetrates the second and / or third head portion and can thus serve as a guide for a relative movement of these head portions, provided that they are designed to the first head portion längsaxial movable.

Of course, if the first and second head sections form a (longitudinally axial) fixed unit, the firing pin can also be connected to the second head section.

It is particularly advantageous in this case, when a percussion piston of Erdbohrgeräts, which is driven by a pressurized fluid to reciprocal movements, first impinges on a contact surface of the firing pin and thus transmits the impact energy to the chisel tip and the first and the first and second Bohrkopfabschnitt.

Only in a second step, the impact energy is transmitted to the third head portion or the associated housing of the device. For this purpose, the percussion piston can impinge on a contact surface of the housing or of the second head section after a certain forward movement of the firing pin.

Alternatively, the firing pin may have a contact surface which, after a certain forward movement of the firing pin, strikes a corresponding contact surface of the housing / of the third head section.

In a three-stage propulsion of the drill, the three head portions are accordingly sequentially applied by the percussion piston of the drill - directly or indirectly -.

In an advantageous embodiment, the connection between the third head portion and the housing is designed positively. This is particularly advantageous in terms of ease of maintenance. The drill head can be changed quickly and easily. Thread connections and / or bayonet closures are advantageously suitable for this purpose. Any other form-fitting, but also non-positive connection types are possible.

Alternatively, the connection can also be produced by welding, for which the friction welding method is particularly suitable. The connection by welding is particularly suitable when the shortest possible length of the device is required.

However, in addition to the above-mentioned any types of component connections can be used and also in terms of welding processes, the connection is not limited.

In a particularly advantageous embodiment, the loosened soil behind the first drill head section with oil, bentonite or other fluid is mixed. However, an entry of the fluid can also take place before the first head section.

For this purpose, bores can be provided in the housing or in one of the head sections, which preferably introduce the fluid used radially into the loosened soil.

The mixing of the soil with a fluid can serve to reduce the skin friction of the redrawn housing. In addition, it can increase the occurring cohesion of the displaced soil, so that the stability of the well is improved and burglaries of the well occur in reduced numbers.

The present invention will be explained in more detail with reference to embodiments shown in the drawings, wherein similar components of the various embodiments are provided with identical reference numerals.

Fig. 1

in einer geschnittenen Seitenansicht einen Ausschnitt eines Erdbohrgeräts mit einem erfindungsgemäßen Bohrkopf in einer ersten Ausführungsform;

Fig. 2

ein Bauteil des ersten Bohrkopfabschnitts der Ausführungsform aus Fig. 1 in einer Frontansicht;

Fig. 3

eine zweite Ausführungsform eines erfindungsgemäßen Bohrkopfs in einer perspektivischen Seitenansicht;

Fig. 4

den Bohrkopf gemäß Fig. 3, wobei der bewegliche Teil des Bohrkopfs in vorauseilender Position dargestellt ist;

Fig. 5

eine dritte Ausführungsform eines erfindungsgemäßen Bohrkopfs in einer perspektivischen Ansicht;

Fig. 6

eine vierte Ausführungsform eines erfindungsgemäßen Bohrkopfs in einer perspektivischen Ansicht;

Fig. 7

eine fünfte Ausführungsform eines erfindungsgemäßen Bohrkopfs in einer perspektivischen Ansicht.

In the drawings shows:

Fig. 1

in a sectional side view of a section of a Erdbohrgeräts with a drill head according to the invention in a first embodiment;

Fig. 2

a component of the first drill head portion of the embodiment Fig. 1 in a front view;

Fig. 3

a second embodiment of a drill head according to the invention in a perspective side view;

Fig. 4

according to the drill head Fig. 3 wherein the movable part of the drill head is shown in an anticipatory position;

Fig. 5

a third embodiment of a drill head according to the invention in a perspective view;

Fig. 6

a fourth embodiment of a drill head according to the invention in a perspective view;

Fig. 7

a fifth embodiment of a drill head according to the invention in a perspective view.

Fig. 1 shows the front part of a ram boring machine, consisting of a housing 1 and an associated drill head according to the invention in a first embodiment.

The drill head consists essentially of the components, striker 2, cutting ring 3 and displacer 4. striker 2 and cutting ring 3 together form in this embodiment, a first drill head portion, the second head portion, here in the form of the displacer 4 and the third head portion 11 axially is mobile. For this purpose, the displacer 4 and the third head section 11 are guided on the firing pin 2.

The rear end of the firing pin 2 protrudes into a working space 5 of the housing 1, in which a percussion piston (not shown), driven by a pressurized fluid, reciprocates. In the case of the forward movement of the ram boring machine, the percussion piston first strikes the end of the firing pin 2 protruding into the working space 5 and accelerates it in the direction forward. As a result, the firing pin is driven together with the bit tip 6 and the cutting ring 3 in the soil to loosen this or to smash occurring obstacles.

Both the displacer 4 and the housing 1 are initially not moved.

Depending on the design of the device, the percussion piston hits the housing 1 or the displacer 4 on the contact surface 7 of the housing 1 after a certain relative movement of the striker 2, or the striker 2 with a shoulder 12 strikes the contact surface 8 of the displacer component 4. As a result, the housing 1 is accelerated together with displacer 4 and follows the movement of the cutting ring 3. In this case, the displacer 4 compresses the loosened soil and produces a borehole with the diameter of the housing first

In Fig. 2 can be the radial arrangement of the blades 9 recognize that arise by a corresponding dimensioning of the discharge channels 10.

After completion of a movement stroke supports a spring 14, here in the form of a spiral spring, the complete return of the two relatively movable parts of the drill head to the starting position.

The drill head according to the invention is designed so that it can be used as a unit from the front into the housing 1 and fixed there. This is particularly advantageous for maintenance work, since the drill head has the most stressed components and consequently is subject to the highest wear during operation. A simple replacement of the drill head is thus possible.

In addition, drill bits with different shapes, such as those in the Fig. 3 to 7 are shown, depending on the requirement quickly and easily connected to the housing.

The Fig. 3 and 4 show an alternative embodiment of the drill head according to the invention. Here, the first (cutting ring 3) and second (displacer 4) drill head section are designed as a unit firmly connected to each other. This unit is further connected to the firing pin 2, which in turn serves as a guide for the axially movable to the other two head portions third head portion 11. The third head portion 11 is connected via the thread 13 with the housing of a drill.

The displacer 4 differs in particular from that of the first embodiment in that it has only individual conical sections. These are interrupted by further cutting, which are arranged in alignment with a respective discharge channel 10 of the cutting ring 3.

The Fig. 3 and 4 show the same embodiment in different positions. In Fig. 3 the movable part of the drill head is shown in its retracted position. The play between the shoulder 12 of the percussion piston 2 and the striking surface 8 of the third drill head section 11 can clearly be seen. At the same time, the play between the second and third drill head sections is minimal. In Fig. 4 the movable part of the drill head is shown in an anticipatory position. Accordingly, the clearance between shoulder 12 and face 8 is minimal and maximum between the second and third bits.

The further embodiments according to Fig. 5 to 7 in particular show different shapes for the cutting ring 3. These different shapes are in principle for all according to the invention and in particular the two embodiments according to Fig. 1 respectively. Fig. 3 and 4 equally suitable.

The in the Fig. 5 illustrated embodiment differs from the first embodiment in particular by the shape of the cutting. These are formed substantially trapezoidal. The recesses thus obtain a U-shape in contrast to the V-shaped recesses in the first embodiment.

In the in Fig. 6 illustrated embodiment, the cutting ring consists of two halves, the cutting edges are rotationally offset from one another. In this way, solids that have not been shattered by the front cutting ring half meet the cutting edges of the rear cutting ring half.

In the embodiment according to Fig. 7 The longitudinal edges of the cutting edges are at an angle of approximately 45 ° to the longitudinal direction of the drill head or the drill.

Claims (26)

1. Use of a boring head, comprising at least three boring head sections (3, 4, 11), wherein a first boring head section (3) is located at the front in a boring direction and has discharge passages (10), a subsequent second boring head section (4) has an outer surface formed with largely conical sections rising in opposition to the boring direction, and a third boring head section (11) has a base for fixing the boring head to a housing (1) of the ground-boring device, and wherein the discharge passages (10) of the first boring head section (3) are dimensioned such that a plurality of radially-arranged blades (9) are formed, for displacement boring, through displacing earth with a percussive action.
2. Use according to Claim 1, characterised in that the front edges of the blades (9) are oriented substantially perpendicular to the longitudinal axis of the boring head.
3. Use according to any one of the preceding claims, characterised in that the third boring head section (11) is positively connected to the housing (1).
4. Use according to any one of claims 1 or 2, characterised in that the third boring head section (11) is welded to the housing (1).
5. Use according to any one of the preceding claims, characterised in that the boring head has one or more fluid outlets in front of and/or in the region of the second boring head section (4).
6. Use according to any one of the preceding claims, characterised in that the discharge passages (10) are arranged at an angle of between 0° and 45° to the longitudinal axis of the ground-boring device.
7. Use according to any one of the preceding claims, characterised in that the boring head has V-shaped discharge passages (10).
8. Use according to any one of the preceding claims, characterised in that the boring head has trapezoidal blades (9).
9. Use according to any one of the preceding claims, characterised in that the first boring head section (3) has two cutting rings, which each have discharge passages (10), such that in each case a plurality of radially-arranged blades (9) are formed, the two cutting rings being rotationally offset from one another, such that the discharge passages (10) of the first cutting ring are aligned with the blades (9) of the second cutting ring.
10. Boring head for a ground-boring device displacing earth with a percussive action comprising at least three boring head sections (3, 4, 11), wherein a first boring head section (3) is located at the front in a boring direction and has discharge passages (10), a subsequent second boring head section (4) has an outer surface formed with largely conical sections rising in opposition to the boring direction, and a third boring head section (11) has a base for fixing the boring head to a housing (1) of the ground-boring device, characterised in that at least two of the boring head sections (3, 4, 11-) are axially movable relative to one another with respect to the longitudinal axis of the boring head, and wherein the discharge passages (10) of the first boring head section (3) are dimensioned such that a plurality of radially-arranged blades (9) are formed.
11. Boring head according to Claim 10, characterised in that the first (3) and second (4) boring head section are fixedly connected to one another along their longitudinal axis, and the third boring head section (11) is movable relative to these.
12. Boring head according to Claim 10, characterised in that the second (4) and third (11) boring head section are fixedly connected to one another along their longitudinal axis, and the first boring head section (3) is movable relative to these.
13. Boring head according to Claim 10, characterised in that the front edges of the blades (9) are oriented substantially perpendicular to the longitudinal axis of the boring head.
14. Boring head according to any one of claims 10 to 13, characterised in that the diameter of the first boring head section (3) corresponds substantially to the diameter of the subsequent housing (1).
15. Boring head according to any one of claims 10 to 14, characterised in that the largest diameter of the first boring head section (3) is greater than the smallest diameter of the second boring head section (4).
16. Boring head according to any one of claims 10 to 15, characterised in that the first boring head section (3) has a percussion bolt (2) guided in the second (4) and/or third (11) boring head section.
17. Boring head according to Claim 16, characterised in that the percussion bolt (2) has a chisel point (6) projecting into the earth.
18. Boring head according to any one of claims 16 or 17, characterised in that a percussion piston firstly strikes a contact surface of the percussion bolt (2) and, after a further forward movement, strikes a contact surface (8; 7) of the second (4) or third boring head section (11) or of the housing (1).
19. Boring head according to any one of claims 16 to 18, characterised in that, after a certain forward movement, a contact surface of the percussion bolt strikes a contact surface of the second (4) or third (11) boring head section or of the housing (1).
20. Boring head according to any one of claims 10 to 19, characterised in that the third boring head section (11) is positively connected to the housing (1).
21. Boring head according to any one of claims 10 to 19, characterised in that the third boring head section (11) is welded to the housing (1).
22. Boring head according to any one of claims 10 to 21, characterised by one or more fluid outlets in front of and/or in the region of the second boring head section (4).
23. Boring head according to any one of claims 10 to 22, characterised in that the discharge passages (10) are arranged at an angle of between 0° and 45° to the longitudinal axis of the ground-boring device.
24. Boring head according to any one of claims 10 to 13, characterised by V-shaped discharge passages (10).
25. Boring head according to any one of claims 10 to 24, characterised by trapezoidal blades (9).
26. Boring head according to any one of claims 10 to 25, characterised in that the first boring head section (3) has two cutting rings, which each have discharge passages (10), such that in each case a plurality of radially-arranged blades (9) are formed, the two cutting rings being rotationally offset from one another, such that the discharge passages (10) of the first cutting ring are aligned with the blades (9) of the second cutting ring.

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