EP2558672A2

EP2558672A2 - Ground-drilling device

Info

Publication number: EP2558672A2
Application number: EP11717182A
Authority: EP
Inventors: Franz-Josef Püttmann
Original assignee: Tracto Technik GmbH and Co KG
Current assignee: Tracto Technik GmbH and Co KG
Priority date: 2010-04-16
Filing date: 2011-04-08
Publication date: 2013-02-20
Anticipated expiration: 2031-04-08
Also published as: PL2558672T3; US9328560B2; US20130025936A1; DE102010015465A1; WO2011128045A3; EP2558672B1; WO2011128045A2

Abstract

The invention relates to a ground-drilling device with a basic body and with a drilling head movably mounted in relation thereto in the longitudinally axial direction, wherein a clearance, which is variable in its size owing to the movable mounting, is formed between the drilling head and the basic body, and with a sealing element for sealing the clearance with respect to the surroundings, wherein the sealing element is designed as a valve element which opens when an overpressure prevails inside the clearance, in order to produce a pressure equalization, and which is closed when a negative pressure prevails inside the clearance, in order to prevent a pressure equalization.

Description

..Erdbohrvorrichtung "

The invention relates to a Erdbohrvorrichtung with a base body and a movable thereto in the longitudinal axial direction drill head.

An earth boring device with a relative to a base movably mounted drill head is known for example from DE 195 08 542 A1. This is a self-propelled Erdbohrvorrichtung, a so-called Erdrakete. This Erdrakete has a base body within which a percussion piston is mounted movably in the longitudinal axial direction. The percussion piston is forced into a cyclic reciprocating motion by the supply of compressed air, with the percussion piston impinging on a front impact surface at each cycle, ultimately transferring the kinetic energy of the percussion piston to the body of the launcher in the soil. The front striking surface is formed by a firing pin, which is part of a drill head of the Erdrakete. The drill head is movably mounted in the longitudinal body in the main body; to guide the relative movement between the drill head and the main body of the firing pin is mounted within a corresponding opening of the body. The firing pin has at its extending in the base body section still has an annular shoulder whose diameter is greater than the diameter of the opening in the body. This paragraph is used to transfer the energy initially transferred from the percussion piston on the firing pin or the drill head after a defined relative movement between the drill head and the main body on the body. The propulsion of the earth rocket in the soil is thus carried out in two stages: First, the drill head is driven a certain distance by

CONFIRMATION COPY the percussion piston strikes the impact surface of the firing pin; after a defined relative movement of the drill head to the main body of the annular shoulder of the firing pin then strikes a striking surface of the body, whereby the remaining energy is transferred to the body to track these the drill head in the bore.

The annular shoulder of the firing pin forms with the corresponding portion of the base body a free space whose size varies depending on the position of the drill head relative to the base body. This space is connected via the annular gap between the annular shoulder and the inner wall of the body with the working chamber of the body, within which the percussion piston is moved cyclically. Although this annular gap is small, but not sealed for cost reasons, so that it may come to a (partial) pressure equalization between the working chamber and the free space, whereby compressed air, which has been passed in a drive phase of the percussion piston in the working chamber, flows into the free space , Since the pressure balance between the free space and the working chamber is relatively slow, it may come to the venting of the working chamber that in the free space, an overpressure prevails that hinders a return movement of the drill head in its retracted position. To prevent this, it is provided to additionally connect the free space with the surroundings, so that an overpressure forming in the free space can be discharged not only to the working chamber but also to the surroundings. In the case of the Erdrakete DE 195 08 542 A1 this is done on the turn unsealed storage of the firing pin in the opening of the body.

With the pressure balance between the free space and the environment has the disadvantage that the entry of contaminants from the outside into the free space is enhanced by the already unsealed storage of the firing pin; Because of the movement of the drill head relative to the housing in its forward position is due to the speed at which this movement takes place, first creates a negative pressure in the free space, which "pulls" the contaminants in the free space Wear of the mobile components of the earth rocket and can cause the mobility of the drill head is limited or lost.

Based on this prior art, the present invention seeks to provide an improved Erdbohrvorrichtung with a movable drill head. In particular, in the Erdbohrvorrichtung invention, the penetration of undesirable contamination in the space formed between the movable drill head and the body of the Erdbohrvorrichtung space to be prevented. This object is solved by the subject matter of independent claim 1. Advantageous developments of the Erdbohrvorrichtung invention are the subject of the dependent claims and will become apparent from the following description of the invention.

The essence of the invention, the formed between the movable drill head and the body space in which the atmosphere partially under pressure and partially positive pressure, sealed by a sealing element, which is inventively designed so that it acts as a valve element, the one within the free space prevailing overpressure and seals at a pressure prevailing within the free space vacuum to prevent ingress of dirt into the free space as possible.

An earth boring device according to the invention therefore has a base body and a drill head movably mounted for this purpose in the longitudinal axial direction (i.e., the drilling direction), wherein a free space which is variable in size by the movable bearing is formed between the drill head and the base body; Furthermore, a sealing element is provided for sealing the free space relative to the environment, wherein the sealing element is designed as a valve element which opens at a pressure prevailing within the space pressure to produce a pressure equalization and which is closed at a prevailing within the free space negative pressure to a pressure compensation to prevent.

An earth boring device according to the invention can be any device with which bores and in particular horizontal bores can be introduced into the ground. However, these are particularly preferably self-propelled earth boring devices, so-called ground rockets, which are equipped with an internal impact mechanism (percussion piston) which is driven by the supply of a pressure fluid and in particular a compressed gas (compressed air).

In a preferred embodiment of the earth boring device according to the invention, the sealing element has a sealing lip designed as an oblique extension. Such a sealing lip on the one hand ensures the desired function for opening a passage only at an overpressure and on the other hand easy to manufacture and thus inexpensive.

In a further preferred embodiment of the drilling device according to the invention, the sealing element is formed or integrated into the Erdbohrvorrichtung that a defined Durchläse between the free space and the environment is formed, the passage is released depending on the pressure conditions or closed by the sealing lip. Such a defined passage between see the clearance and the environment allows pressure equalization, as far as this is necessary for the function of the movable drill head. By still provided according to the invention sealing lip of this defined space can be sealed in a simple manner, if the occurrence of contaminants in the free space is to be prevented in accordance with the invention.

Preferably, it can be provided that the sealing element has a recess into which the sealing lip can dip in order to release the passage between the free space and the environment in the event of overpressure. This can in turn ensure the most unhindered pressure equalization between the free space and the environment in the event of overpressure in the free space.

Since both the housing and the drill head of Erdbohrvorrichtungen regularly have a circular cross section, the sealing element according to the invention can be integrated in a simple manner in this, if this is designed as a sealing ring.

In a preferred embodiment of the earth boring device according to the invention, the sealing element may comprise exclusively or additionally at least one adapted vent hole, which connects the free space with the environment. This vent hole can be carried out so small (ie adapted) that this is done at a prevailing in the space pressure over a pressure gas flow from the space into the environment, but at the same time a suction of dirt at a prevailing in the free space vacuum (this is regularly only for a short time and with a lower (compared to the overpressure) differential pressure before) largely prevented. An intake of contaminants through the vent hole can also be prevented by an adapted integration of the vent opening in the sealing element, for example by the sucked flow is deflected several times before it enters the free space. These deflections can prevent contaminants, in particular in the form of relatively heavy particles or droplets, from actually penetrating into the free space.

In a particularly preferred embodiment, it may be provided to combine the at least one vent opening with another sealing part (in particular a sealing lip) of the sealing element which acts as a valve element. The vent opening can then be arranged so that the pressure gas flow emerging from the vent at a clearance prevailing in the free space flows into the area in front of, for example, the sealing lip, whereby the sealing lip, which can take over the actual function of pressure equalization, is freed from contamination. is held. As a result, a permanent function of the sealing lip can be ensured.

As already stated, the earth boring device according to the invention is preferably designed as a self-propelled earth rocket and thus has an oscillating inside the housing percussion piston which can cyclically impinge on a front impact surface of the Erdrakete to propel the Erdbohrvorrichtung in the drilling direction.

Such an inventive ground rocket may preferably further comprise a threaded ring with an external thread which is screwed into a corresponding internal thread of the housing and which serves to transmit the energy transmitted by the percussion piston to the housing. This threaded ring may preferably also serve as a bearing for the movable drill head, for which purpose the earth drilling device may further comprise a firing pin which is connected to the drill head and extends through the threaded ring. The striker may project beyond the threaded ring such that the striker piston first impacts the striker and thereby moves the bit relative to the housing.

Since such a threaded ring serves to transmit the impact energy, it must be replaced relatively frequently. The connection of the threaded ring with the housing in the form of a threaded connection can ensure a simple and quick replaceability. A disadvantage of a threaded connection in a Erdbohrgerät may, however, that it is sensitive to contamination, since a soiled threaded connection often can not solve or only with the aid of tools again. In a preferred embodiment of the earth boring device according to the invention can therefore be provided that the sealing ring is formed or integrated into the Erdbohrvorrichtung that this seals at the same time the threaded connection between the threaded ring and the housing from the environment.

In order to simplify the assembly and disassembly of the Erdbohrvorrichtung invention may also be provided to connect the threaded ring with the sealing element according to the invention (solid), so that both elements can be used as a unit in the Erdbohrvorrichtung or removed from this again. This can be done in any way. Preferably, however, it is provided that the sealing element, if it is designed as a sealing ring, is attached to a cylindrical projection of the threaded ring. By providing a projection of the (elastic) sealing ring and a corresponding recess in the cylindrical projection of the threaded ring can also be achieved that the projection of Sealing ring engages in the recess of the threaded ring and thus produces a positive connection between the two elements.

The sealing element of the Erdbohrvorrichtung invention may of course be formed in several parts.

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

In the drawings shows:

1 shows a section of a Erdbohrvorrichtung invention in a sectional side view. and

2 shows a perspective view of individual elements of the earth boring device of FIG. 1.

In Fig. 1, the front portion of a Erdbohrvorrichtung invention is shown in a sectional side view. In this section, the Erdbohrvorrichtung consists essentially of a base body 1 and a relative to the base body 1 movably mounted drill head 2. The main body 1 comprises a housing 3, in the rear portion of a percussion piston 4 is movably mounted. The percussion piston 4 is placed in known manner by means of compressed air, which is supplied to the Erdbohrvorrichtung at its rear end (not shown) via a compressed air line, in an oscillating motion, wherein they are in the drilling operation of the Erdbohrvorrichtung in each cycle of their movement on a front striking surface impinges to transmit the kinetic energy of the percussion piston 4 in two stages, first on the drill head 2 and then on the housing 1 of the Erdbohrvorrichtung to propel the Erdbohrvorrichtung in the ground. In the illustrated Erdbohrvorrichtung is therefore an earth rocket.

The percussion piston 4 hits in its forward movement, first on the rear end of a firing pin 5, which is a part of the drill head 2 and extends into the working chamber 6 of the main body 1, in which the percussion piston 4 is movably mounted.

The front end of the firing pin 5 forms a drill head tip 7, which ensures due to their relatively small diameter for a high directional stability of the Erdrakete in the movement through the soil. Behind the drill head tip 7, two annular drill head elements 8, 9 are connected in succession to the firing pin 5. The connection is made by means of two fastening bolts 10th The front drill head element 8 forms a plurality of radially aligned cutting elements 11, the radial extent of which corresponds substantially to the radius of the housing 3 and consequently to the radius of the bore to be created. Between two adjacent cutting elements in each case a channel is formed, the channel base 12 - seen from front to rear - is formed rising. During the propulsion of the drill head 2, the cutting elements 11 cut into the ground and solve this, which is then discharged through the formed between the cutting elements 11 channels to the rear. Due to the increasing geometry of the channel bottoms 12, the soil is already displaced radially outward and compacted. This compression is continued by the rear drill head element 9, whose lateral surface is conically formed in its front portion and whose diameter widens to a diameter (viewed from front to back), which corresponds to that of the housing 3 of the Erdrakete.

Unlike the known from the prior art Stufenbohrköpfen can be achieved by the present drill head, which has a plurality of radially extending cutting elements 11, which already substantially correspond to the final diameter of the bore, a particularly high directional stability of the Erdrakete their movement in the ground , Of course, it is also possible to use the Erdbohrvorrichtung invention with any other drill head, such as with a conventional Stufenbohrkopf.

The storage of the firing pin 5 in the base body 1 is taken over, inter alia, by a threaded ring 13, which is screwed into the front end of the housing 3. For this purpose, the threaded ring 13 has an external thread and the housing has a corresponding internal thread. At the rear end of the threaded ring 13, a threaded bushing 14 connects, which also has an external thread which engages in a corresponding internal thread of the housing 3. Between the threaded bushing 14 and the corresponding portion of the firing pin 5, an annular space is formed in which a cylindrical 15 is arranged. This coil spring 15 is supported on the front side in each case on a projection of the threaded bushing 14 and on the rear side on a projection of the firing pin 5.

Once the percussion piston 4 impinges on the rear end of the firing pin 5, this and the other associated elements of the drill head 2 is displaced relative to the main body 1 of the Erdrakete forward. Due to the relative movement of the firing pin 5 to the threaded bushing 14, the cylindrical coil spring 15 is compressed, whereby a bias voltage is generated, which later supports the return movement of the drill head 2 in its retracted home position. After a defined forward movement of the firing pin 5 relative to the base body 1, an annular shoulder 16 of the firing pin 5 strikes the rear end of the threaded bushing 14. In this way, the remaining in the firing pin 5 kinetic energy is also transferred to the base body 1 of the ground rocket, so that the main body 1 is then propelled together with the drill head 2 in the ground. The rear end of the threaded bushing 14 thus forms a front striking surface of the main body 1 of the Erdrakete.

After the energy, which has been transferred by a stroke of the percussion piston on the firing pin 5, has been fully implemented, the propulsion of the Erdrakete comes to a standstill in the ground. Due to the bias of the coil spring 15 of vorverlagerte drill head is retracted back to its original position. Meanwhile, the percussion piston 4 is guided in a further cyclical movement, wherein the interaction repeats in a renewed impact of the percussion piston on the rear end of the firing pin.

The forces that are transmitted from the shoulder 16 of the firing pin 5 on the threaded ring 13 are transmitted via the screw with the housing 3 on this. Since these are considerable loads, it is necessary to secure the threaded bush 14 in order to prevent it from being displaced from the intended position by the impacts. This securing the threaded bush 14 is achieved by the threaded ring 13 which is supported via a spacer ring 17 at the front end of the threaded bushing 14.

As is apparent from Fig. 2, the threaded ring 13 is slotted on one side in the longitudinal axial direction, wherein the slot at the end of the threaded bush 14 facing end is conically formed in a portion. In this slot, a spreader 18 is used, which has a threaded bolt 19 which can be screwed to a threaded sleeve 20. By screwing the threaded bolt 19 into the threaded sleeve 20, a conical head portion 21 of the expansion element is drawn into the corresponding conical portion of the slot, whereby the threaded ring 13 is spread. In this way, the surface pressure of the threaded connection between the threaded ring 13 and the housing 3 is increased, thereby achieving a secure fit of the threaded ring 13 and thus also the threaded bushing 14 in the housing 3.

At its front end of the threaded ring 13 is provided with a cylindrical projection 22 which serves to receive a sealing ring 23 according to the invention. The sealing ring 23 is made of an elastic material (eg elastomer) and forms on its inner surface a projection 24 which can engage in a corresponding recess 25 of the cylindrical projection 22 of the threaded ring 13. This allows a secure connection of the threaded ring 13 can be achieved with the sealing ring 23, so that the two components handled as a unit and in particular built into the Erdrakete or can be removed from this. The sealing ring 23 further forms a through hole 26, which serves to receive the threaded sleeve 20.

The movable mounting of the firing pin 5 in the base body 1 results in a connection between the working chamber 6, in which the percussion piston 4 is movably guided, and the free space 27, between the rear Bohrkopfelement 9 and the firing pin 5 (as parts of the drill head ) and the sealing ring 23, the threaded ring 13 and the spacer ring 17 (as parts of the base body 1) is formed. In order to keep the Erdrakete constructive as simple as possible, no seal is provided, which would reliably prevent the temporary in the working chamber 6 prevailing high pressure leads to an overflow of the compressed air therein into the space 27. Consequently, an overpressure (with respect to the vicinity of the earth rocket) is generated at times in the free space 27, which must be compensated relatively quickly again, since otherwise this would hinder the return movement of the drill head 2 supported by the helical spring 15. This pressure equalization is achieved, inter alia, that an annular gap 28 is formed between the rear drill head element 9 and the sealing ring 13, via which the pressure compensation between the free space 27 and the environment can take place.

However, this annular gap 28 has the disadvantage that relatively easy soiling (in particular soil and water) can penetrate from the environment into the free space 27, whereby at least the wear of the moving parts increases and the mobility of these parts would be hindered. The risk of contamination penetration is in particular because of the forward movement of the drill head, the free space is temporarily increased quickly, whereby (temporarily) a negative pressure (relative to the environment) is generated. By this negative pressure soiling can be sucked through the annular gap.

To prevent this, the sealing ring 23 is provided with a sealing lip 29, which is formed obliquely pointing backwards. Due to the special design of the sealing lip 29, this can be deformed at a pressure prevailing in the free space 27 overpressure, whereby they can dive into a located next to the sealing lip 29, annular recess 30 of the sealing ring 23. As a result, the annular gap 28 is released. On the other hand, if a negative pressure relative to the environment prevails in the free space 27, this negative pressure causes the sealing lip 29 to be pressed against the inner surface formed by the rear drill head element 9, thereby closing the annular gap 28. The sealing ring 23 further comprises two small oppositely arranged vent openings 32 which, in conjunction with two flats 33 in a front shoulder of the cylindrical projection 22, establish a connection between the free space 27 and the environment. Through these vent openings 32, a compressed gas flow can take place from the free space into the environment in the event of an overpressure prevailing in the free space. At the same time, however, an intake of dirt in a prevailing in the space 27 vacuum is largely prevented because the vents 32 on the one hand have only a relatively small diameter and on the other so arranged in the sealing ring 23 or integrated into the Erdbohrvorrichtung that an air flow is deflected several times from the environment into the free space 27 (see Fig. 1) before it enters the free space 27. These deflections prevent contaminants from penetrating into the free space due to their inertia.

The vent openings 32 open in the mounted state of the sealing ring 23 in the formed between the sealing ring 23 and the rear Bohrkopfelement 9 gap and thus - seen from the environment - in front of the sealing lip 29. The temporarily emerging from the vent holes 32 compressed air can prevent Contaminations accumulate on the side of the sealing lip 29 facing the gap, which may affect the function of the sealing lip 29 after prolonged use of the earth boring device.

The sealing ring 23 additionally has an annular sealing bead 31, which bears partially against the front end of the housing 3. This sealing bead 31 prevents contaminants from penetrating into the threaded connection between the threaded ring 13 and the housing 3. This can ensure that the threaded connection can be solved after a long use of Erdrakete without much effort.

Claims

claims:

1. Erdbohrvorrichtung with a base body (1) and a movable longitudinally axial direction drill head (2), wherein between the drill head (2) and the base body (1) by the movable storage in its size variable clearance (27) is formed characterized by a sealing element for sealing the clearance (27) from the environment, wherein the sealing element is formed as a valve element which opens at an overpressure prevailing within the clearance (27) to establish a pressure equalization, and at one within the clearance ( 27) prevailing vacuum is closed to prevent pressure equalization.

2. Erdbohrvorrichtung according to claim 1, characterized in that the sealing element comprises a formed as an inclined extension sealing lip (29).

3. Erdbohrvorrichtung according to claim 2, characterized in that the sealing element is formed or integrated into the Erdbohrvorrichtung that a defined passage between the free space (27) and the environment is formed, the passage released depending on the pressure conditions or of the Sealing lip (29) is closed.

4. Erdbohrvorrichtung according to claim 3, characterized in that the sealing element has a recess (30) into which the sealing lip (29) can dip to release the passage between the free space (27) and the environment in the event of overpressure.

5. Erdbohrvorrichtung according to any one of the preceding claims, characterized in that the sealing element is designed as a sealing ring (23).

6. Erdbohrvorrichtung according to one of the preceding claims, characterized by at least one adapted vent opening (32) through which the free space (27) is connected to the environment.

7. Erdbohrvorrichtung according to any one of the preceding claims, characterized by a within the base body (1) oscillating moving percussion piston (4) which cyclically impinges on a front striking surface of the Erdbohrvorrichtung to propel them.

8. Erdbohrvorrichtung according to claim 7, characterized in that the base body (1) comprises a housing (3) with an internal thread and a threaded ring (13) with an external thread, wherein the threaded ring (13) at least is partially screwed into the housing (3), and the Erdbohrvorrichtung further comprises a firing pin (5) which is connected to the drill head or a part thereof and extends through the threaded ring (13) and projects beyond it, whereby the percussion piston ( 4) impinges on the firing pin (5) and thereby moves the drill head (2) relative to the housing (3).

9. Erdbohrvorrichtung according to claim 8, characterized in that the sealing element seals the threaded connection between the threaded ring (13) and the housing (3) relative to the environment.

10. Erdbohrvorrichtung according to claim 8 or 9, characterized in that the Dichtelment with the threaded ring (13) is connected.

11. Erdbohrvorrichtung according to claim 10, characterized in that the sealing element is designed as a sealing ring (23) and is mounted on a cylindrical projection (22) of the threaded ring (13).

12. Erbohrvorrichtung according to claim 10 or 11, characterized in that the sealing ring (23) tensile and / or pressure-resistant manner with the threaded ring (13) is connected.