Background

The invention relates to an arrangement for installing a casing.

The invention further relates to a method for installing a casing. An effective way to install a casing or pole to hard ground when the casing is driven partly into a rock, for example, is percussive drilling. In such a case, a casing has inside it boring pipes, and at an end of the boring pipe, a percussion hammer, such as a down-the-hole-hammer, or DTH hammer. A boring pipe has a centre opening through which compressed air required by the DTH hammer is fed to it. To the DTH hammer is connected a pipe drive crown, pilot crown, and a reamer is connected to the pilot crown by, for example, bayonet locking. The boring pipe, DTH hammer, pilot crown and reamer connected to the latter are simultaneously rotated by a rotation mechanism at the top end of the boring pipe.

The boring of the hole takes place by means of the percussion function generated by the hammer, and the rotation of the boring pipe. The purpose of the reamer is to broaden the hole made by the pilot crown so big that the casing fits into the drilled hole. The casing may additionally have a so-called drill shoe by means of which the pilot crown pulls the casing with it into the drilled hole. The removal of released material takes place by means of discharge air of the DTH hammer.

The casing may be installed in the ground by other methods, such as by pushing it in by its top end. In this case, at the top part of the casing, a vibrator is typically installed, producing vibration that enhances the insertion of the cas- ing. The material that has pushed itself inside the casing is later removed by a scoop or borer designed for this.

The method has the following drawbacks. Percussive drilling is a most efficient way to break hard material, but is not the best option for the removal of soft material, such as clay or silt. Pushing or vibrating a casing into the ground is efficient in soft ground, but boulders or rock in the ground may stop the advance of the casing. In addition, the material left inside the pipe has to be removed by a separate work phase. Brief disclosure

The arrangement and method of the invention are characterized by what is disclosed in the independent claims. The other embodiments of the invention are characterised by what is disclosed in the rest of the claims.

Inventive embodiments are also disclosed in the specification and drawings of this application. The inventive content of the application may also be defined differently than in the claims presented below. The inventive content may also consist of several separate inventions, particularly if the invention is examined in the light of disclosed or implicit subtasks or from the point of view of gained advantages or groups of advantages. In such a case, some of the definitions in the claims below may be irrelevant to the separate inventive ideas. The features of the different embodiments of the invention may be applied to other embodiments within the scope of the basic inventive idea.

The advantage of the invention is that varied ground may be bored in an efficient way.

Brief description of the figures

The invention is described in more detail in the accompanying drawings, in which

Figure 1 is a schematic view obliquely from above of a detail of an arrangement for installing a casing and having a bore,

Figure 1 b is a schematic view of a detail of the arrangement in Figure 1 a in cross section,

Figure 1 c is a schematic side view of the cross section of the arrangement in Figure 1 a,

Figure 2a shows the arrangement of Figure 1 a provided with a percussion hammer in cross section from a side, and

Figure 2b is a schematic view of a detail of the arrangement in Figure 2a in cross section.

For the sake of clarity, the figures show the invention in a simplified manner. Similar parts are indicated in the figures by the same reference numbers.

Detailed description

Figure 1 a is a schematic view obliquely from above, Figure 1 b in cross section, and Figure 1 c in cross section and from a side of a detail of an arrangement for installing a casing and having a bore. The arrangement 100 comprises a casing 1 , which is a tubular piece installed in the ground, typically permanently. At the installation stage of the casing 1 , a bar part 2 has been adapted inside it to be rotated inside the casing. In an embodiment, the bar part 2 comprise a screw-like wing 3 on its outer perim- eter, and third fastening means 10 arranged on the distal end 5 of the bar part, so the bottom end of the bar part.

The screw-like wings 3 lift the released material out of the casing 1 . The removal of material may be enhanced by blowing air through an inner opening adapted in the bar part, to the bottom of the opening.

In a second embodiment, the bar part 2 excludes the wings. In a third embodiment, the bar part 2 comprises wings on a portion of its length.

The arrangement 100 further comprises a borer 6, which comprises fourth fastening means 1 1 . The borer 6 may be fastened detachably by the fourth fastening means 1 1 to said third fastening means 10. In the embodiment presented in the Figure, the third and fourth fastening means 10, 1 1 establish a HEX joint, but it is obvious that the joint may be another joint.

The purpose of the borer 6 and, in particular, a blade part 15 adapted to it, is to release material by cutting.

The arrangement 100 further comprises a reamer 8, adapted mova- ble to a distal end 9 of the casing so that the reamer 8 has a free travel F in the direction of the longitudinal axis X of the casing. According to an idea, the free travel is at least 1 mm, advantageously 3 to 10 mm.

The advantage of the free travel is that the reamer 8 and casing 1 may be used not only with the borer 6 but also with a percussion hammer, as will be explained below.

The reamer 8 removes material from the outer perimeter of the hole so that the hole being bored is adequately large for the casing 1 .

According to an idea, the reamer 8 is adapted to rotate around the longitudinal axis X of the casing, in other words it is able to rotate in the direction of the perimeter of the casing 1 . In an embodiment, the reamer 8 is adapted to rotate around the longitudinal axis X of the casing by an unlimited rotating angle, that is, rotation after rotation.

In an embodiment, the borer 6 comprises first fastening means 4, and the reamer 8 second fastening means 7. These may be detachable coupled to each other so that the reamer 8 may be fed against the ground with a feeding force conveyed to the borer 6 from the bar part 2 and rotated with a rotating movement conveyed to the borer 6 from the bar part 2.

The first and second fastening means 4, 7 are typically of the bayonet type. Such fastening means may be released from each other by an opposite rotating movement.

In an embodiment, the arrangement 100 comprises a drill shoe 12 fastened to the casing 1 by welding, for example, and arranged to couple to the borer 6 - and percussion hammer as will be described below. The drill shoe 12 conveys the axial, ground-penetrating motion of the borer 6 (or percussion ham- mer) as a movement taking the casing 1 further in the direction of its longitudinal axis X.

Figure 2a shows the arrangement of Figure 1 a provided with a percussion hammer in cross section from a side, and Figure 2b a cross section of a detail of the arrangement shown in Figure 2a. Here, at the distal end 5 of the bar part, and inside the casing 1 , is connected a percussion hammer 13.

The percussion hammer comprises a pilot crown 14 and fourth fastening means 1 1 as does the borer 6. Thus, the percussion hammer 13 may be fastened in place of the borer 6 to the third fastening means 10 of the bar part.

The percussion hammer 13 further comprises first fastening means 4, just like the reamer 6 does, by means of which the percussion hammer 13 may be detachable fixed to the second fastening means 7 on the reamer. Like this, the reamer 8 is adapted to be rotated by means of the rotating movement of the bar part 2, conveyed by the percussion hammer 13. With the very same fastening means 4, 7, a longitudinal percussive load is conveyed to the reamer 8 from a pilot crown 14, allowing the boring function of the reamer 8.

Due to the free travel F, the percussive movement of the percussion hammer 13 is only directed on the casing in case the casing 1 leaves behind of the reamer 8. In this case, the percussive movement pulls the casing 1 forward, and the reamer 8 may yet again move freely forward.

The drill shoe 12 is arranged to couple to the percussion hammer 13 and adapted to convey the axial movement of the percussion hammer 13 as a movement taking the casing 1 forward in the direction of its longitudinal axis X.

The arrangement 100 described in the above may be used according to, for example, the following method.

A. The casing 1 is taken into the ground in its soft portion by boring, with the use of the borer 6 and reamer 8. B. The portion of hard ground and/or rock is bored with percussive boring with the percussion hammer 13 by the use of the pilot crown 14 and the reamer 8 referred to in the above.

So, in this embodiment of the method, the borer 6 or percussion ham- mer 13 is installed in the third fastening means 10 of the bar part 2, and if there is a substantial change in the ground, the borer 6 is replaced with the percussion hammer 13, or the percussion hammer 13 with the borer 6. In practise, this is performed so that the possible locking between the first and second fastening means 4, 7 is opened, and the bar part 2 is pulled out of the casing 1 . Next, the locking between the third and fourth locking means 10, 1 1 is opened, and the reamer 6 or percussion hammer 13 is detached. In its place either the borer 6 or percussion hammer 13 is installed, and the bar part 2 together with the installed tool is inserted in the casing 1 . Following this, the possible locking between the first and second fastening means 4, 7 is locked, and the drilling of the hole is continued for as long as the casing 1 is at the desired depth, or until the ground again changes to the extent that it is advantageous to replace the tool.

One and the same reamer 8 takes part in installing the casing regardless of whether the borer 6 or percussion hammer 13 is being used.

In a second embodiment of the arrangement 100, the borer 6 and percussion 13 have their own bar parts 2. The borer 6 or percussion hammer 13 may detachably or fixedly fastened to its bar part. In such a case, as the ground changes from soft to hard, the borer 6 and the bar part 2 that rotated it are lifted out of the casing 1 , and a bar part 2 that has a percussion hammer 13 at its end is adapted in its place. The procedure is naturally the opposite if the ground changes from hard to soft. In the embodiment, too, one and the same reamer 8 takes part in installing the casing regardless of whether the borer 6 or percussion hammer 13 is being used. If the arrangement 100 has the first fastening means 4 on the borer 6 and/or percussion hammer 13, and second fastening means 7 on the reamer 8, the process is as described previously in this description.

In some cases, features disclosed in this application may be used as such, regardless of other features. On the other hand, features disclosed in this application can be combined, if necessary, to form various combinations.

In summary, it may be noted that the arrangement according to the invention is characterised in that it comprises a casing, a bar part adapted to be rotatable inside the casing, and furthermore a borer which comprises a blade part to release material, the borer being adapted at a distal end of the bar part and to be rotated with the bar part, as well as a reamer adapted movably to the distal end of the casing so that the reamer has a free travel in the direction of the longitudinal axis of the casing.

It may further be noted that the method of the invention is character- ised by the method using the arrangement described in this description, and: drilling a soft portion of the ground by boring with the use of the borer, blade part, and reamer, and a portion of hard ground and/or rock is bored with percussive boring with a percussion hammer and by the use of a pilot crown and the aforementioned reamer.

The drawings and their disclosure are only intended to illustrate the idea of the invention. It is apparent to a person skilled in the art that the invention is not restricted to the embodiments described above, in which the invention is disclosed through some examples, but various modifications and different applications of the invention are feasible within the inventive idea defined in the ac- companying claims.

Reference markings

1 casing

2 bar part

3 wing

4 first fastening means

5 distal end of bar part

6 borer

7 second fastening means

8 reamer

9 distal end of casing

10 third fastening means

1 1 fourth fastening means

12 drill shoe

13 percussion hammer

14 pilot crown

15 blade part arrangement free travel of reamer longitudinal axis of casing