GB2466897A

GB2466897A - Overdrilling head for displacing the ground surrounding a pipe and a method for overdrilling

Info

Publication number: GB2466897A
Application number: GB1006946A
Authority: GB
Inventors: Hans-Joachim Bayer; Reinhold Menne; Frank Goecke
Original assignee: Tracto Technik GmbH and Co KG
Current assignee: Tracto Technik GmbH and Co KG
Priority date: 2007-10-23
Filing date: 2008-10-15
Publication date: 2010-07-14
Anticipated expiration: 2028-10-15
Also published as: GB201006946D0; WO2009052981A3; GB2466897B; DE102007050931A1; WO2009052981A2; DE102007050931B4

Abstract

The invention relates to an overdrilling head (1) for displacing ground surrounding a pipe, comprising an elongated base body (2) that is suitable for at least partially embracing the pipe to be overdrilled and has a front end (3) and a back end (4). At the back end, a connecting means (5) is provided for connecting the base body (2) to an element of a heading work, with which the overdrilling head (1) can be driven forward. At the front end (3), a front surface optionally comprising a plurality of individual surfaces (6, 7, 8, 9) is provided, extending from a rear part of the front surface, in which at least one point (P1) on the front surface is located on a first plane (E1) that is arranged perpendicular to the longitudinal axis of the base body, to a front part of the front surface, in which at least one point on the front surface is located on a second plane (E2) arranged perpendicular to the longitudinal axis of the base body. In the longitudinal direction (L) of the base body, the second plane (E2) is located further forward than the first plane (E1), and the point (P1) in which a line originating from the connecting means and disposed parallel to the longitudinal axis of the base body intersects the front surface is not located on the second plane (E2).

Description

uOverdrilling head for displacing the ground surrounding a pije and method for overdrillincf The invention relates to an overdrilling head for trenchless replacement or excavation of pipes and to a method for overdnlling.

In order.to replace pipes without digging trenches, it is known to remove the grdund, surrounding the pipe to be replaced, from the pipe with an overdrilling head guided along the pipe. As a result, when subsequently pulling or pushing out the pipe, the friction resistance between the pipe to be replaced and the surrounding ground is reduced, so that the pipe can be pulled out from the ground with little effort.

DE 10 2005 050 932 B3 discloses an overdrilling device, which has a substantially tubular, elongated base body, which can comp!etely embrace the pipe to be overdrilled. At a front end of the base body a nozzle ring is provided. This can be rotated about the longitudinal axis of the base body by means of a rotary drive. At the back end of the base body a surface pointing backwards is provided which runs at an angle to the longitudinal axis of the base body differing from 900.

Furthermore, it is known in practice to use overdrilling heads which have no rotatably driven elements provided on the base body. The ground surrounding the pipe is displaced here, on the one hand, by liquid discharge from nozzles in the front region of the base body as well as by the base body swinging to and fro about its longitudinal axis. * S S...

I

**I*II * I Overdrilling heads are generally driven forwards with drill rods. The foremost rod ::. section of the drill rod is connected by threads, bayonet fittings or other connections to the back end of the overdrilling head. In some cases, a fixed connection to the overdrilling head, by welding for example, can also be provided. I **I

I

In some cases, problems during overdrilling have arisen if the overdrilling head and the elements of the advance heading following it had to be fed through between a pipe and an obstacle lying close to the pipe. This was particularly the case with those drilling situations in which cover plates were laid above the pipes to be excavated.

Thus, for example, it is usual in the UK to lay a pipe by digging a trench and on refilling the trench with earth to place a row of protective plates in the ground directly above and along the entire pipe. The particular purpose of these plates is that in the event of subsequent excavation an excavator firstly strikes the concrete plate lying in the ground. As a result, the excavator is prevented from inadvertently fracturing the pipes. The distance from the pipes to the protection covers arranged above them can amount to less than 40 mm. 20 mm is not uncommon.

Against this background, the object forming the basis of the invention was to propose an overdrilling head for displacing the ground surrounding a pipe, which also allows the overdrilling head to be deployed in difficult environmental conditions. Furthermore, a method for overdrilling was to be proposed.

This object is achieved by the subject matter of the independent claims.

Advantageous embodiments are specified in the dependent claims.

The invention originates from the basic concept of using an overdrilling head with a front surface which is not completely located in a plane, which runs *...* 25 perpendicular to the longitudinal axis of the base body, and also of designing the overdrilling head so that the foremost point of the front surface is not located in a ***** * line with the connecting means, to which an element of an advance heading, with :.:::. which the overdrilling head can be driven forwards, is connected. * * **e** * *

In the case of the overdrilling head according to the invention, the foremost point of the front surface is not provided in front of the connecting means. This enables the overdrilhing head to be guided with the foremost part of its front surface between the pipe to be overdrilled and the protective cover, while the elements of the advance heading, which are not suitable for such overdrilling due to their diameter, and the connecting means can be guided to the side or preferably underneath the pipe.

The overdrilling head according to the invention for displacing the ground surrounding a pipe has an elongated base body, which is suitable for at least partially embracing the pipe to be overdrilled. This elongated base body has a front end and a back end. At the back end a connecting means for connecting the base body to an element of an advance heading, with which the overdrilling head can be driven forwards, is provided. At the front end of the base body, a front surface optionally formed from a plurality of individual surfaces is provided. This front surface is not completely arranged in a plane, which stands at right angles to the longitudinal axis of the base body. Rather, the front surface can be inclined forwards, for example, or it can also be aligned forwards in steps. The front surface namely has a rear part, with at least one point on the front surface being located in a first plane that is arranged perpendicular to the longitudinal axis of the base body. From this rear part, the front surface extends to a front part, with at least one point on the front surface being located in a second plane that is arranged perpendicular to the longitudinal axis of the base body, wherein the second plane is located in the longitudinal direction of the base body further forward than the first plane.

* In order to avoid the foremost point of the front surface being located in front of the :::. connecting means, it is arranged that the point, with a line parallel to the longitudinal axis of the base body and coming from the connecting means intersecting the front surface, is not located on the second plane. * *

The pipe to be overdrilled can be a cable or cable loom, but can also, for example, be a pipe.

In a particularly preferred embodiment, the foremost point of the front surface is formed opposite the connecting means, therefore offset rotated by 1800 about the longitudinal axis of the base body. This embodiment enables a drill rod, which can be used as an advance heading, to be guided underneath the pipe to be excavated, while the foremost point of the front surface can be fed through above the pipe to be excavated between the pipe to be excavated and a protective cover lying above the pipe. It is particularly preferred if the foremost point of the front surface is arranged offset relative to the connecting means rotated by more than 450, for example by 900, or, as stated, by 180° about the longitudinal axis of the base body.

In a preferred embodiment, the front surface is designed so that at least one point on the front surface, which is located in the first plane, is formed opposite a further point of the front surface, which, however, is located on the second plane, therefore offset rotated by 180° about the longitudinal axis of the base body.

In a preferred embodiment, the point of the front part of the front surface, which is located in the second plane, is the foremost point of the front surface.

Furthermore, in a preferred embodiment the point of the rear part of the front surface, which is located in the first plane, at the same time, is the rearmost point of the front surface. * * *

*�**** * The connecting means of the overdrilling head can be a thread, a bayonet fitting or ::. other types of connection. The connecting means can also be a fixed connection to an element of the advance heading, for example a weld seam. *.*** * *

When, in connection with the description of the invention, it is stated that the connecting means is located in a plane, this means that the centre point of the connecting means is located in this plane, therefore for example in the case of a thread a point on the central axis of the thread, which is the same distance from the beginning of the thread to the end of the thread. However, in the sense to be applied here, a line coming from the connecting means does not necessarily have to be understood as such a line which originates from this centre point. That is to say, it is possible that the connecting means is fixed to the base body in such a manner that a line coming from this centre point of the connecting means and parallel to the longitudinal axis of the base body does not intersect the front surface at all. -For example, this is the case if the connecting means is provided at the radially outermost edge of the base body. According to the invention, locating the foremost point of the front surface in front of the connecting means is to be avoided. This is particularly the case if all intersections of lines, which are aligned parallel to the base body and come from any point of the connecting means, are not located with the front surface on the second plane. This relates to all the lines, which come from the connecting means and are arranged parallel to the longitudinal axis of the base body, which actually intersect the front surface, and does not exclude that there are further lines coming from the connecting means, which are aligned parallel to the base body, which do not intersect the front surface at all.

In a preferred embodiment, the base body is substantially tubular and, at least in the sections which do not belong to the front end or to the back end, has a substantially circular cross-section. As a result, when overdrilling pipes it has been * S *** proved particularly advantageous if the base body completely encompasses the * * pipe to be overdrilled. It is also possible to use a base body which only has a : *. cross-section in the form of an arc of a circle. This is particularly advantageous if S...

** pipes have to be overdrilled which have been laid in a particularly twisting manner.

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The front surface of the overdrilling head, engaging with the ground located in front of the overdrilling head when drilling forwards, can have various geometrical shapes. Thus, the front surface can consist of a single surface, that is to say, for example, it can be located completely in a plane, which runs at an angle to the longitudinal axis of the base body differing from 900. The front surface can likewise * be formed in steps. For example, it can have a first individual surface substantially in the form of an arc of a circle, which is located in the first plane, and a second individual surface substantially in the form of an arc of a circle, which is located in the second plane. The two individual surfaces in the form of an arc of a circle are then joined by transitional surfaces in order to complete the front surface, which can be aligned parallel to the longitudinal axis of the base body, but can also be aligned at an angle to the longitudinal axis of the base body.

In particularly preferred embodiments, the overdrilling head is symmetrical.

Particularly preferably, the front surface is mirror-symmetrical relative to the plane, in which the longitudinal axis of the base body and the connecting means are located. Furthermore, the front surface relative to the plane, in which the longitudinal axis of the base body is located and which is arranged perpendicular to the plane, in which the longitudinal axis of the base body and the connecting means are located, can be mirror-symmetrical. Particularly preferably, at least one point on the front surface, which is located in the second plane, is also located in the plane, in which the longitudinal axis of the base body is located, and which is arranged perpendicular to the plane, in which the longitudinal axis of the base body and the connecting means are located. * *

In a particularly preferred embodiment, the base body at least in the regions, * *. ..* * which are located behind the part of the front surface, which is located in the second plane, has a wall thickness of less than 120 mm, particularly preferably of less than 40 mm and most particularly preferably of less than 30 mm. As a result, *...s* * S the overdrilling head can also be used in environmental conditions where an obstacle is located close to the pipe to be overdnlled.

In a preferred embodiment, the connecting means has a central axis and the base body at least in the region of the connecting means is designed with a cross-section in the form of an arc of a circle. This cross-section has a central axis in the form of an arc of a circle. The connecting means in this preferred embodiment is formed on the base body in such a manner that the central axis of the connecting means is arranged offset relative to the central axis of the cross-section in the form of an arc of a circle radially towards the longitudinal axis of the base body. As a result, the connecting means only slightly projects over the outer peripheral surface of the base body. This simplifies advance heading.

In a preferred embodiment, the peripheral surface, adjoining the front surface, runs substantially parallel to the longitudinal axis of the base body, wherein the transitional area of the front surface to the peripheral surface can at least partially run inclined to the longitudinal axis of the base body.

In a preferred embodiment, nozzles are provided in the front surface. These can also be provided in recesses in the front surface.

The method according to the invention arranges that, when overdrilling a pipe laid in the ground, which runs adjacent to an obstacle, the overdrilling head according to the invention overdrills the pipe such that the connecting means is not guided between the pipe to beoverdnlled and the known obstacle.

* The invention is described below in detail by means of a drawing illustrating only exemplary embodiments, wherein: *.* * * *S*IS* * S Fig. I shows an overdnlling head according to the invention in a lateral view, Fig. 2 shows the overdnlling head shown in fig. 1 in a perspective view, Fig. 3 *shows the front section of an alternative design of an overdnlling head according to the invention in a perspective view, Fig. 4 shows the front section of the alternative design according to Fig. 3 in a lateral view, Fig. -5 shows the front section of a further overdrilling head according to the invention in a perspective view, Fig. 6 shows the front section of the alternative design according to Fig. 5 in a lateral view, Fig. 7 shows the front section of a further overdnlling head according to the invention in a lateral view, Fig. 8 shows the front section of the alternative design according to Fig. 7 in a perspective view, Fig. 9 shows the front section of a further overdrilling head according to the invention in a perspective view and * * **S** * Fig. 10 shows the front section of the alternative design according to Fig. 9 : *. inalateral view. S... *S *** S *

The overdrilling head 1 shown in Fig. I has an elongated, tubular base body 2.

The base body is designed to completely embrace the pipe to be overdnlled. In the sections, which do not belong to the front end 3 or to the back end 4 of the base body 2, the base body 2 has a substantially circular cross-section.

At the back end 4, a rod-shaped connecting means 5 is provided. At its free end, the rod-shaped connecting means 5 can be connected to an element of an advance heading, with which the overdrilling head can be driven forwards, to the first section of a drill rod, for example. For this purpose, the free end of the connecting means 5 has the shape required for this.

At the front end 3 of the base body, a front surface formed from individual surfaces 6, 7, 8, 9 is provided. The individual surface 6 of the front surface forms a rear part of the front surface. All points of the front surface, which are part of the individual surface 6, are located in a first plane El arranged perpendicular to the longitudinal axis of the base body. The individual surface 8 forms a front part of the front surface. A point of the individual surface 8, that is to say, the foremost point of the individual surface 8, is located in a second plane E2, arranged perpendicular to the longitudinal axis the base body. The second plane E2 is located in the longitudinal direction of the base body 2 further forward than the first plane El. The point P1, in which a line parallel to the longitudinal axis L of the base body 2 and coming from the centre point M of the connecting means 5 intersects the front surface, is not located on the second plane E2 but on the first plane El.

The front surface is mirror-symmetrical relative to the plane, in which the S * * longitudinal axis L of the base body and the connecting means are located. * *

The foremost point of the front surface, that is to say, the point which is located in the second plane E2, is formed opposite the connecting means 5, therefore offset rotated by 180° about the longitudinal axis of the base body.

*.b*.* * S -10-Nozzle openings 10 are provided in the individual surface 6 of the front surface. In addition, further nozzle openings 11 are provided in the region of the front end 3 of the base body on the interior peripheral surface of the base body 2.

The connecting means 5 has a central axis. The base body 2 has a cross-section in the form of an arc of a circle in the region of the connecting means 5. In the embodiment illustrated in Figs. I and 2, the connecting means 5 is formed on the base body 2 in such a manner that the central axis of the connecting means 5 is arranged offset relative to the central axis of the cross-section in the form of an arc of a circle of the base body 2 radially away from the longitudinal axis L of the base body 2. In a preferred embodiment, which is not illustrated, the connecting means is designed in such a manner that the central axis of the connecting means 5 is arranged offset relative to the central axis of the cross-section in the form of an arc of a circle of the base body 2 radially towards the longitudinal axis L of the base body 2.

In the case of the overdrilling head I shown in Figs. I and 2, the peripheral surface 13 adjoining the front surface is aligned substantially parallel to the longitudinal axis L of the base body 2. The transitional area 14 of the front surface to the peripheral surface 13 runs at least partly inclined to the longitudinal axis L of the base body 2.

Fig. 3 and Fig. 4 show the front region of an alternative embodiment of the overdrilling head according to the invention. The same components are designated with the same reference symbols. The embodiment shown in Fig. 3 * * differs from that shown in Figs. I and 2, in that recesses for further nozzle : *. openings 12 are provided in the individual surface 8. S... * *

S - -11 -

In Fig. 5 and Fig. 6, the front region of a further embodiment of the overdnlling head according to the invention is illustrated. The same elements are also designated with the same reference symbols. The front surface is formed from individual surfaces 20, 21, 22, 23. At least one point of both the individual surface 20 and the individual surface 22 is located on a first plane E3 arranged perpendicular to the longitudinal axis of the base body. All points of the individual surfaces 21, 23 are located on a second plane E4 arranged perpendicular to the longitudinal axis of the base body. The second plane E4 is located in the longitudinal direction of the base body further forward than the first plane E3. The front surface is mirror-symmetrical relative to the plane, in which the longitudinal axis of the base body and the connecting means are located. Furthermore, the front surface is mirror-symmetrical relative to the plane, in which the longitudinal axis of the base body is located, and which is arranged perpendicular to the plane, in which the longitudinal axis of the base body and the connecting means are located. Furthermore, the points P4, P5 on the front surface are located both in the second plane and in the plane, in which the longitudinal axis of the base body is located, and which is arranged perpendicular to the plane, in which the longitudinal axis of the base body and the connecting means are located.

In Fig. 7 and Fig. 8, the front section of a further exemplary embodiment of the overdrilling head according to the invention is illustrated. The front surface is a continuous surface running at an angle to the longitudinal axis of the base body differing from 900. It has a rear part, in which the point P6 on the front surface is located in a first plane arranged perpendicular to the longitudinal axis of the base 25. body. The front surface runs from this-rear part to a front part of the front surface, with the point P7 being located in a second plane arranged perpendicular to the * longitudinal axis of the base body. * *n * * *..S

In Fig. 9 and Fig. 10, the front section of a further exemplary embodiment of the óverdrilling head according to the invention is illustrated. This exemplary * S embodiment upgrades the one shown in Fig. 3 and Fig. 4 to the extent that the individual surface 22 is shorter and steeper than the individual surface 20.

Furthermore, the individual surfaces 21 and 23 are rounded, so that only the foremost point P4, P5 of these individual surfaces 21 and 23 is located in the plane E4. This embodiment is particularly suited for straight overdrilling, since the effect of the inclined individual surfaces 20, 22 on the drilling direction is completely or at least almost completely nullified. S. * S..

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Claims

Claims: 1. Overdrilling head (1) for displacing the ground surrounding a pipe having -an elongated base body (2) which is suitable for at least partially embracing the pipe to be overdrilled and has a front end (3) and a back end (4), -wherein at the back end a connecting means (5) for connecting the base body (2) to an element of an advance heading, with which the overdrilling head (I) can be driven forwards, is provided and -at the front end a front surface optionally formed from a plurality of individual surfaces (6, 7, 8, 9, 20, 21, 22,23) is provided, -which extends from a rear part of the front surface, in which at least one point on the front surface is located in a first plane (El) that is arranged perpendicular to the longitudinal axis of the base body (2), to a front part of the front surface, in which at least one point on the front surface is located in a second plane (E2) arranged perpendicular to the longitudinal axis of the base body (2), characterized in that the second plane (E2) is located in the * longitudinal direction of the base body (2) further forward than the first plane (El) and the point (P1), in which a line parallel to the longitudinal axis (L) of the base body (2) and coming from the connecting means(5) intersects the front surface, is not located on the second plane.
2. Overdrilling head according to Claim 1, characterized in that the front surface relative to the plane, in which the longitudinal axis (L) of the base S.....body (2) and the connecting means (5) are located, is mirror symmetrical. * S* * S * *5*S

:. *
3. Overdrilling head according to Claim I or 2, characterized in that the front surface relative to the plane, in which the longitudinal axis (L) of the base *55*50 S 0 -14 -body (2) is located and which is arranged perpendicular to the plane, in which the longitudinal axis (L) of the base body (2) and the connecting means (5) are located, is mirror-symmetrical.
4. Overdnuling head according to any one of Claims I to 3, characterized in that at least one point (P4, P5) on the front surface, which is located in the second plane, is also located in the plane, in which the longitudinal axis (L) of the base body (2) is located and which is arranged perpendicular to the plane, in which the longitudinal axis (L) of the base body (2) and the connecting means (5) are located.
5. Overdrilling head according to any one of Claims I to 4, characterized in that the front surface is a continuous surface running at an angle to the longitudinal axis (L) of the base body (2) differing from 900.
6. Overdrilling head according to any one of Claims I to 4, characterized in that the front surface has a first individual surface substantially in the form of an arc of a circle, which is located in the first plane and has a second individual surface, substantially in the form of an arc of a circle, which is located in the second plane.
7. Overdrilling head according to any one of Claims I to 6, characterized in that the base body (2) is substantially tubular and has a substantially circular cross-section. * . S..
8. Overdrilling head according to any one of Claims I to 7, characterized in S.....* that the base body (2) at least in the regions, which are located behind the part of the front surface, which is located in the second plane, has a wall thickness of less than 120 mm. *.S.SS S
9. Overdrilling head according to any one of Claims I to 8, characterized in that the connecting means (5) has a central axis and the base body (2), at least in the region of the connecting means (5), has a cross-section in the form of an arc of a circle, wherein the connecting means (5) is formed on the base body (2) in such a manner that the central axis is arranged offset relative to the central axis of the cross-section in the form of an arc of a circle radially towards the longitudinal axis (L) of the base body (2).
10. Overdrilling head according to any one of Claims I to 9, characterized in that the peripheral surface (13), adjoining the front surface, runs substantially parallel to the longitudinal axis (L) of the base body (2), wherein the transitional area of the front surface to the peripheral surface can at least partially run inclined to the longitudinal axis (L) of the base body (2).
11. Overdrilling head according to any one of Claims Ito 10, characterized in that nozzles are provided in the front surface.
12. Method for displacing the ground surrounding a pipe by overdrilling the pipe to be excavated, characterized in that when overdrilling a pipe laid in the ground, which runs adjacent to an obstacle, the overdrilling head according to Claims I to 11 overdrills the pipe in such a manner that the connecting means (5) is not guided between the pipe to be overdrilled and the known obstacle. * I S.IS..... * * * SI SI * *S *S*S *I.. SS.S S