The object of the invention is an arrangement and a method for drilling a hole, according to the preambles of the independent claims presented below.

Numerous constructions, which are arranged in the soil, have a foundation, the purpose of which is among others to transfer and divide the load caused by the construction into the soil and anchor the construction to be immoveable.

There are many methods of laying a foundation and many factors affect the choice of the used method, such as the weight and the shape of the construction to be founded, the characteristics of the soil and the durability demands and cost of the foundation.

In areas which have frost, the soil frost causes particular demands on the foundation. Especially light foundation is difficult with known techniques. By light foundation is meant for example light foundation bases or steel wedges. Almost invariably mail boxes, fence poles or traffic signs are askew, because the soil frost moves the foundation. Light foundations reaching below the soil frost depth are however generally not financially reasonable to make.

Drilling into the soil is, in addition to certain foundation methods, common also in other excavation. When drilling a hole, soil easily comes loose from the edges of the hole, which soil can obstruct the hole at least partly. In connection with the drilling, a protective tube can be installed into the drilling hole to keep it open. In order to be able to install the protective tube easily into the hole, the diameter of the hole should be approximately as large as or slightly larger than the outer diameter of the protective tube. The diameter of the hole can be made sufficiently large for example with a drill bit, the diameter of the head of which is slightly larger than the outer diameter of the tube. The problem is that because of its size, the head of the bit cannot be pulled through the protective tube up from the ground, and it is however often desirable to leave the protective tube in the drilling hole. In one known solution the head of the bit is detached and left in the ground. The problem is among others that a new bit head is needed for each hole. In another solution the head of the bit can be bent so that it fits inside the tube and can be pulled up through the tube. Here the problem is that the structure of the bit is not especially simple, since the bit comprises moving parts. In this case the bit is susceptible to damage and expensive.

Document US 2004/0084217 which is considered the closest prior art document discloses a protective tube for keeping open a drilling hole. The protective tube has a gap in its longitudinal direction.

It is an object of this invention to reduce or even completely eliminate above-mentioned problems appearing in the prior art.

It is an object of this invention to provide a solution, where the entire bit can be pulled out of a hole drilled in the ground through the protective tube, without there being a need for bending, moving or detachable parts in the bit.

In order to attain, among others, the objects mentioned above, the arrangement and the method for drilling a hole according to the invention are characterised in what is presented in the characterising parts of the enclosed independent claims.

The embodiments mentioned in this text relate, where applicable, to the protective tube, the arrangement, the method for drilling a hole, the use of the protective tube and the arrangement and the system in the soil even though it is not always specifically mentioned.

A typical protective tube for keeping a drilling hole open has a first end and a second end, and at least one gap, which is mainly in the longitudinal direction of the tube, has been arranged in its mantle, which gap passes through the mantle in its thickness direction, and at least one hole has been arranged in its first end.

Preferably the mantle of the protective tube has at least one gap, mainly in the longitudinal direction of the protective tube, which gap extends from the first end of the protective tube to the second end.

Preferably, several holes have been arranged in the first end of the protective tube, such as 1, 2, 3, 4, 5, 10, 15, 20 or 30 holes. The diameter of the holes can be for example 5 - 50 mm or 1 - 20 % of the diameter of the protective tube. The diameter of the holes can thus be, among others, 5 - 25 mm, 10 - 30 mm, 10 - 50mm, 25 - 50mm or 1 - 10%, 2 - 20%, 5 - 10 % or 10 - 20 % of the diameter of the protective tube.

In this application the term tube can also be used for the protective tube. The length of the protective tube can be for example 30 cm - 10 m, 30 cm - 2 m, 50. cm - 150 cm, 2 m -10 m or 2 m - 8 m. The diameter of the tube can be e.g. 1 - 100 cm, 1 - 80 cm, 1 - 15 cm or 20 - 100 cm. The thickness of the mantle of the tube can be e.g. 1 - 50 mm, 1 -10 mm, 1 - 25 mm or 10 - 50 mm.

The shape of the cross section of the protective tube can be for example a circle, an oval, a quadrangle or another suitable shape. The protective tube can be made of e.g. plastic or metal, such as steel or iron.

According to an embodiment of the invention the width of the gap in the direction of the circumference of the tube is for example 1 mm - 15 cm, 1 mm - 1 cm, 5 mm -10 cm or 1 cm - 8 cm.

In the embodiment, where the gap extends from the first end of the tube to the second end, the drill bit can be partly arranged to pass along the gap and pulled or otherwise moved through the protective tube out of the drilling hole.

According to an embodiment of the invention the gap is wider in the second end of the protective tube than in its first end. In that case the drill bit can easily be steered into the gap.

According to an embodiment there are two gaps In the protective tube. In that case a bit can be pulled through the tube, the dimension in the direction of the diameter of the tube of which bit exceeds the diameter of the tube in two places. In connection with such an embodiment a separate additional part is preferably used, which part is arranged in the second end of the protective tube to keep the parts of the protective tube together. The gaps may be for example symmetrically placed in relation to the central axis of the protective tube, whereby a rotationally symmetrical bit can be used instead of an eccentric bit.

The object of the invention is further an arrangement for drilling a hole in the soil, acording to claim 1.

According to the invention the drill is an eccentric drill, i.e. its bit is not rotationally symmetrical in relation to its rod part. Such drills are known as such to a person skilled in the art. This invention has the advantage that the eccentric drill can be removed from the protective tube as it is, i.e. it does not need to be collapsed etc. Thereby the drill and especially its bit is substantially less expensive than drills according to prior art.

The object of the invention is further the use of the arrangement according to the invention for drilling a hole in the soil.

In a typical method according to the invention for drilling a hole in the soil

• a drilling hole is drilled into the soil,
• a protective tube for keeping the hole open is arranged into the drilling hole simultaneously with the drilling, and
• the drill bit is pulled out of the drilling hole through the protective tube.

Typically at least a part of the drill bit is arranged to pass along a gap arranged in the mantle of the protective tube at least mainly in the longitudinal direction of the protective tube, when the drill bit is pulled out of the drilling hole.

In a method according to an embodiment of the invention the protective tube is expanded with the aid of a wedge after the drill bit has been pulled out of the drilling hole. By expanding is meant that the cross-sectional area of the tube is increased substantially in the direction which is perpendicular to the longitudinal direction. Thereby the protective tube can be made to be compressed more firmly against the walls of the hole and the friction with the surrounding soil is increased.

According to an embodiment of the invention the wedge is arranged in the gap in the mantle of the tube for example by striking or pushing. According to another embodiment a counterpart is arranged inside the tube, which counterpart broadens out and expands the tube, when the counterpart is struck or pushed with a wedge or another suitable tool.

According to an embodiment of the invention, binder is fed to the inside of the protective tube, such as cement powder, concrete or other plaster or chemical grout, such as resin. The feeding of the binder can take place either simultaneously with the drilling, or once the drilling is already finished. The binder spreads around the protective tube through the gap and the drill bit.

In one embodiment holes have been arranged in the mantle of the protective tube, through which holes the binder, which has been fed to the inside of the tube, is able to transfer to the outside of the tube. This transfer can be promoted by pushing the binder on the inside of the tube with piston means.

According to an embodiment of the invention at least two protective tubes are arranged successively in connection with each other in the longitudinal direction of the tubes in order to form a longer tube. Two tubes can e.g. be attached to each other with suitable attaching means, such as tongue and groove counterparts arranged in the ends of the tube. The gaps of the tubes are preferably to be arranged aligned with each other substantially in the same line, which can be achieved e.g. with aligning means, which are arranged in the drill, rod or in the connecting pieces of the tubes.

According to an embodiment of the invention, a tube-like neck part is arranged in connection with the upper end of the protective tube, for example by attaching with attaching means. The diameter of the neck part is larger than the diameter of the protective tube with the gap and also larger that the diameter of the drilling hole, wherefore the neck part is to be pushed into the soil using much more force than the protective tube with the gap, whereby the neck part is settled firmly into the soil and at the same time supports the protective tube with the gap, as an extension of which the neck part is attached. The length of the neck part may be for example 1 - 40 %, 5 - 30 % or 10 - 20 % of the length of the tube of the protective tube with the gap. According to an embodiment the neck part forms a fixed part of the protective tube according to the invention. According to an embodiment of the invention the diameter of the drill rod is substantially as large as the inner diameter of the protective tube.

According to an embodiment of the invention the edges of the gap in the protective tube have been bent towards the inner part of the tube, in such a way that the bent edges settle so close to the drill rod that substantially no soil can pass between them to the space inside the protective tube. According to an embodiment the distance between the edges of the gap and the drill rod may be e.g. 0 -1 mm, 0 - 3 mm, 0 mm -1 cm.

According to an embodiment of the invention there are, in connection with the second end of the protective tube, attaching means for attaching the tube to a drilling device.

In connection with the protective tube and arrangement according to the invention a firing pin can also be used, with the help of which the protective tube is struck into the ground. Such a firing pin is advantageously flange-like and arranged in connection with the second end of the protective tube. A force is exerted on the firing pin, which force makes the protective tube enter into the ground.

A typical system in the soil comprises

• a drilling hole, and
• a protective tube, which is arranged into the drilling hole to keep it open.

According to an embodiment there are at least two drilling holes and protective tubes and the drilling holes are divergent in relation to each other, and the system further comprises a collar part, in connection with which the second ends of the protective tubes are arranged. Binder, such as hardened concrete, could further have been arranged at least inside the protective tube.

The protective tube, arrangement, method and system are well suited for use in connection with drilling of the soil, e.g. in founding and light founding.

It has surprisingly also been discovered that when using a protective tube equipped with holes, binder, and a firing pin, it is possible to make strong and durable light foundations also without using a drill. Thus the protective tube is struck into the ground with the aid of a firing pin, and at the same time binder is fed inside the protective tube, which binder spreads to the surrounding earth via the holes and attaches the protective tube firmly into the soil.

An advantage of the invention as determined in the independent claims is that with its aid a solution is provided, where the entire drill bit can be pulled out of the hole, which was drilled into the ground, through the protective tube, without having a need for bending, moving or detachable parts in the bit.

The invention is described in more detail below with reference to the enclosed schematic drawing, in which

• Figure 1 shows a cross section of a drill bit and a protective tube for keeping a drilling hole open according to prior art,
• Figure 2 shows a drill bit according to prior art, which has a foldable tip,
• Figure 3 shows a cross section of the protective tube of Figures 1 and 2,
• Figure 4 shows a perspective view of the protective tube of Figures 1 - 3,
• Figure 5 shows a protective tube according to a first embodiment,
• Figure 6 shows a protective tube according to the embodiment in Figure 5,
• Figure 7 shows a cross section of the protective tube according to the first embodiment,
• Figure 8 shows a cross section of the protective tube according to a second embodiment,
• Figure 9 shows a protective tube according to a third embodiment,
• Figure 10 shows how a wedge has been pushed into the gap in the mantle of the protective tube,
• Figure 11 shows a protective tube according to a fifth embodiment, into the mantle of which tube holes have been arranged,
• Figure 12 and 13 shows a foundation structure according to a sixth embodiment,
• Figure 14 shows two protective tubes, arranged successively in connection with each other, and
• Figure 15 shows a protective tube according to an eight embodiment, in connection with the upper end of which tube a tube-like neck part has been arranged.

Figure 1 shows a cross section of a drill 1 and a protective tube 2 for keeping a drilling hole open according to prior art. The width d3 of the drill tip 3 is so large that the diameter of the drilling hole it forms is larger than the outer diameter d2 of the protective tube 2. In the position shown, the tip 3 of the drill does not fit into the protective tube 2, since the inner diameter d1 of the tube 2 is smaller than the width d3 of the tip 3. The tip 3 of the drill can at the joint 5 be detached from the connection with the drill rod 4, whereafter the rest of the drill 1 can be pulled out of the drilling hole through the protective tube 2 in the direction of the arrow 10, so that the detached tip 3 remains at the bottom of the drilling hole.

Figure 2 shows a drill 1 according to prior art, which has a foldable tip 3, the width d3 of which is larger than the outer diameter d2 of the protective tube 2 in the open position according to the Figure. The wings 3a, 3b of the tip can be folded towards the drill rod 4 in such a way that the entire drill 1 along with its tip 3 can be pulled out of the drilling hole through the protective tube 2.

Figure 3 shows a cross section of the protective tube 2 of Figures 1 and 2, which cross section in the direction perpendicular to the longitudinal axis of the tube is substantially shaped like a circle.

Figure 4 shows a perspective view of the protective tube 2 of Figures 1 - 3.

Figure 5 shows a protective tube 7 according to the first embodiment. In connection with the protective tube 7 there is a drill 6, which is an eccentric drill, the tip of which drill, i.e. the drill bit 8, is shaped and sized so that the diameter d3 of the drilling hole, which is formed with it, is larger than the outer diameter d2 of the protective tube 7. In this embodiment the drill 6 is thus an eccentric drill, i.e. its drill bit 8 is not rotationally symmetrical. Due to this the protective tube 7 can easily be arranged in the drilling hole when drilling the hole. A longitudinal gap 9, mainly in the longitudinal direction of the tube, has been arranged in the mantle of the protective tube 7. When the drill bit 8 is placed at the gape 9, the drill 6 can be pulled out from the drilling hole through the protective tube 7 in the direction of the arrow 10, i.e. in the longitudinal direction of the tube 7.

Figure 6 shows the protective tube 7 of Figure 5. In the situation shown in the Figure the drill 6 is being pulled out from inside the protective tube 7. A part of the drill bit 8 is arranged to pass along the gap 9 in the mantle of the protective tube 7, wherefore the entire drill 6 along with its bit 8 can be pulled out of or, if desired, arranged back into the drilling hole through the protective tube in the direction of the arrows 10 and 11. The gap 9 extends and is open from the first end 12 of the protective tube 7 to the second end 13.

Figure 7 shows a cross-section of the protective tube 7 according to the first embodiment, seen in a direction which is perpendicular to the longitudinal axis. The gap 9 arranged in the mantle of the protective tube 7, which gap has edges 14, between which the gap is open, passes through the mantle in its thickness direction. Inside the protective tube a cross-section of the drill rod 15 is seen, the diameter d4 of which is substantially as large as the inner diameter of the protective tube 7, wherefore the drill rod 15 substantially fills the inside of the protective tube 7, and substantially no soil can enter therein through the gap 9 during drilling.

Figure 8 shows a cross-section of a protective tube 7 according to the second embodiment, wherein the edges 14 of the gap 9 arranged in the mantle of the protective tube 7 are bent towards the inner part of the protective tube 7 on both sides of the gap 9. The bent edges 14 of the gap are so close to the drill rod 15, that the soil cannot substantially pass between them to the inner space 16 of the protective tube 7.

Figure 9 shows a protective tube 7 according to the third embodiment, wherein the gap 9 in the mantle of the tube widens towards the first end 12 of the tube, i.e. towards the lower end of the tube in the situation in the Figure. The drill bit is easy to fit into such a widened gap 9, when it is desired to draw out the bit from the hole through the protective tube 7.

Figure 10 shows how a wedge 17 has been pushed substantially in the direction of the arrow 11 into the gap 9 in the mantle of the protective tube 7, which tube has been arranged into the ground according to the fourth embodiment of the invention, wherefore the protective tube 7 has expanded in the direction of the arrows 18 and 19, i.e. substantially in the direction of its diameter.

Figure 11 shows a protective tube 7 according to the fifth embodiment, into the mantle of which tube holes 20 have been arranged, especially in connection with the first end 12 of the protective tube 7, i.e. here in connection with the lower end. The aim of the holes 20 is to get the binder, such as cement flour, concrete or other plaster, or the chemical grout, e.g. resin, which is fed to the inside of the protective tube 7, to transfer through the holes 20 from the inside of the protective tube 7 to its outside. According to an embodiment, the binder which is fed to the inside of the protective tube, is pushed or vibrated with a piston instrument 21 in the direction of the arrow 11 so that the binder spreads through the holes 20 to the outside of the protective tube 7.

Figure 12 shows a foundation structure 22 according to the sixth embodiment, , where three protective tubes 7a, 7b, 7c according to the invention form a structure 22 resembling the rootstock of a tree. The tubes 7a, 7b, 7c are arranged into holes, which have been drilled diagonally into the soil. The structure 22 is extremely resistant to stress from compressing, pulling, bending and twisting, In a corresponding manner two, four or more tubes can be used. Binder, such as concrete, can be fed into the tubes 7a, 7b, 7c. A reinforcement bar or equivalent support can also be arranged into the tubes 7a, 7b, 7c. According to an embodiment of the invention the tubes 7a, 7b, 7c comprise at least one gap 9, substantially in the longitudinal direction of the tube. A collar part 23, which can be manufactured of for example concrete, keeps the second ends 13 of the tubes, i.e. here the top ends, together. A connecting means 24 can be arranged in connection with the collar part 23, for connecting the structure to be supported, such as the fence pole, traffic sign, mail box or other pole or pillar to the foundation structure 22. Figure 13 shows the foundation structure 22 of Figure 12 as seen from the direction of the arrow 11.

Figure 14 shows, in accordance with the seventh embodiment, two protective tubes 7d, 7e arranged successively in connection with each other with the aid of connecting means 25. The gaps 9 of the tubes 7d, 7e are aligned. The drill rod 15 moves on the inside of the tubes 7d, 7e.

Figure 15 shows a protective tube 7 according to the eight embodiment, , in connection with the upper end of which tube a tube-like neck part 27 has been arranged via a conical connection 26.

The invention is not meant to be limited to the embodiments shown as examples above but, on the contrary, the aim is to interpret it extensively within the scope of protection defined in the claims below. The reference numbers should not be regarded as restricting the claims.