DE20021835U1 - Drilling anchor - Google Patents

Description

IN THE /&

PATENT ATTORNEYS

„. 224/39184-001

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ROLF BOCKERMANN DIPL-ING.

PETER KOLL
DR-ING. DIPL-ING.

APPROVEDBY
EUROPEAN PATENT OFFICE EUROPEAN PATENT ATTORNEYS MANDATAIRES AGREES EUROPEEN

EUROPEAN TRADEMARK ATTORNEYS

Bergstrasse 159
D-44791 BOCHUM

PO Box 102450
D-44724 BOCHUM

22.12.2000

Schmidt. Kranz & Co. GmbH. 37445 Walkenried

Drilling anchor

It is state of the art to control the effects of rock pressure in underground mining and tunnel construction with the help of anchor support. For this purpose, prefabricated steel anchors are inserted into previously created boreholes in order to connect non-connected rock layers or to suspend loose rock shells from the solid rock. The adhesion of the steel anchors in the boreholes is achieved by mechanically bracing wedge segments (expansion anchors) or by introducing cement suspensions or synthetic resin into the gap between the steel anchors and the walls of the boreholes (adhesive anchors).

Drilling holes in a rocky area for the subsequent setting of steel anchors is often associated with problems. For example, loose rock makes it difficult or even impossible to pull out the drill rods, which can then lead to the loss of the drill rods and inevitably renders the borehole unusable. A new borehole must be drilled.

Telephone (0234) 51957/58/59 ■ Fax (02 34) 51 05 12 ■ e-mail: bochumpatent@t-online.de

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However, the creation of a new borehole means a loss of time and increased costs.

In these cases, drilling rods have been used that can also be used as anchors (drill anchors). In DE 37 24 165 C2, which has become known in this context, a central axial bore runs inside the drilling rod, which continues inside the cutting head, called the drill bit, in a flushing bore that also runs axially. Furthermore, the drilling rod, in the area adjacent to the drill bit, is provided with bores on the circumference that run transversely to the longitudinal axis, the axes of which - starting from the axial bore - extend away from the drill bit at an angle. Furthermore, the longitudinal axes of the transverse bores extend in longitudinal planes that do not intersect the longitudinal axis of the axial bore.

A thread-like profile is provided on the circumference of the drill rod.

The axial bore and the transverse bores serve the purpose, on the one hand, of removing the drilling cuttings that arise during the creation of the borehole by means of flushing water introduced through the axial bores and the transverse bores in the circumferential annular channel and, on the other hand, of introducing an injection medium via the axial bore and the transverse bores after the borehole has been created in order to fix the drilling anchor in the borehole.

Experience in practical use has shown that with the known drill anchor, it is not possible to ensure with the desired level of safety that the annular space on the circumference of the drill anchor and thus its clamping in the borehole is uniformly filled.

The invention is based on the state of the art and the task of creating a drilling anchor that can be fixed perfectly even in very brittle rock and thus does not cause unrelated

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connects rock layers with each other and suspends loose rock shells from the solid mountain range.

According to the invention, this problem is solved by the features of claim 1.

In this context, it is important that the longitudinal channel in the drill rod is closed by the cutting head and that such cross holes are provided near the cutting head, which extend obliquely towards the cutting head on the one hand and obliquely in the other direction on the other. The longitudinal axes of the cross holes run in longitudinal planes that also intersect the longitudinal axis of the longitudinal channel in the drill rod.

Such a drill anchor offers the possibility of different dimensions and design for different load-bearing capacities. It can therefore be used universally. The special arrangement of the cross holes ensures that the direction-oriented cross holes ensure a perfect supply of the flushing agent (flushing water) to cool the cutting head on the one hand and to support the removal of the cuttings via the circumferential annular gap in conjunction with the profiling on the other hand. Furthermore, the injection medium introduced via the longitudinal channel after the borehole has been created can exit at the bottom of the borehole and is then pressed in a direction-oriented manner into the surrounding rock and also in a direction-oriented manner along the drill rod towards the borehole mouth. In this way, a reliable and all-round connection of the drill anchor to the surrounding rock is achieved. Since the cutting head does not have a central, axially aligned flushing or injection channel, interruption of the flushing or injection due to blockage of such a channel is avoided.

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It is particularly advantageous if, according to claim 2, the longitudinal axes of the transverse bores extend at an angle of approximately 35° to the longitudinal axis of the longitudinal channel.

Furthermore, it is expedient that, in accordance with the features of claim 3, the transverse bores open into the concavely rounded thread groove of the circumferentially cylindrical profiling.

According to claim 4, the width of the thread groove of the profiling is larger than the width of the web of the profiling. Such a profiling design advantageously takes into account the different strengths of steel and the injection medium. The shear surface of the injection medium per profiling pass is then several times the shear surface of the steel. In practice, this means that forces acting on the drilling anchor can be absorbed by drill holes of a smaller depth.

According to claim 5, the cutting head can be connected to the drill rod in a detachable or non-detachable manner. This measure makes it possible to use a cutting head that is adapted to the respective rock type.

The features of claim 6 provide that the cutting head is designed in the shape of a truncated cone. This achieves optimal directional stability of the drilling compared to the plate-like drill bits that are part of the state of the art, particularly in rugged mountain formations.

According to claim 7, groove-like depressions are provided on the circumference of the cutting head. Preferably, four depressions are arranged evenly offset from each other by 90°. These depressions serve to better remove the resulting drilling cuttings.

To connect the cutting head to the drill rod, the cutting head is fixed with a pin in the longitudinal channel according to claim 8.

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It can be a cylindrical pin or a threaded pin.

In order to enable the new drilling anchor to be used in rock formations with different hardnesses, the cutting head is provided with cutting edges that ensure increased cutting force, in accordance with the features of claim 9. These cutting edges, which are preferably arranged crosswise on the cutting head, can be made of manganese, hard metal or diamond. Depending on the use of these materials, the drilling anchor can be coupled to drilling equipment that inserts the drilling anchor into the rock by rotating or rotating impact.

Depending on the length of the bore to be made, it is possible according to claim 10 to couple the drill rod equipped with the cutting head to another drill rod with longitudinal channels and a thread-like profile on the circumference in a tension- and pressure-resistant manner via a sleeve that is adapted to the profile on the inside. The essentially cylindrical outer diameter of the sleeve is so large that the annular gap on the circumference of the coupled drill rods is not significantly reduced in order to ensure that the drilling cuttings are removed properly and that the injection medium is introduced safely.

The invention is explained in more detail below using an embodiment illustrated in the drawings.

Figure 1 shows a side view of a drilling anchor;

Figure 2 shows an enlarged vertical longitudinal section of a sleeve for coupling two drill rods of a drill anchor;

Figure 3 shows an enlarged vertical longitudinal section of section III of Figure 1;

Figure 4 shows the representation of Figure 3 shifted by 90° and

Figure 5 is a plan view of the representation of Figure 3 according to the arrow V.

In Figure 1, 1 denotes a drilling anchor. The drilling anchor 1 is used to connect non-contiguous rock layers in underground mining and tunnel construction or to suspend loose rock shells from solid rock.

The drilling anchor 1 comprises a drilling rod 2 with a longitudinal channel 3. The drilling rod 2 is provided with a thread-like profile 4 on the circumference. This profile 4 has a concavely rounded thread groove 5 and a cylindrically designed outer surface 6, whereby a web 22 is formed. The width B of the thread groove 5 is larger than the width B1 of the web 22. The pitch of the profile 4 is approximately 10°.

The drill rod 2 according to Figure 1 can be coupled to another drill rod of the same or different length with the aid of a sleeve 7 which can be seen in Figure 2. For this purpose, the sleeve 7 has a substantially cylindrical outer surface 8 and a profile 9 formed on the inside which is adapted to the profile 4 of the drill rod 2. The ends 10 of the sleeve 7 are slightly conical on the outside.

With the help of sleeves 7 according to Figure 2, several drill rods 2 can be assembled to form a drill string.

At one end 11, the drilling anchor 1 shown in Figure 1 has a truncated cone-shaped cutting head 12 (see Figures 1 and 3 to 5). The cutting head 12 has a maximum diameter that is larger than the outer diameter of the cylindrical surface 8 of the profile 4. It also has cutting edges 13 arranged crosswise (Figure 5), which can be made of a hard metal, for example. Four groove-like

Recesses 14 on the cutting head 12 serve to improve the removal of drilling cuttings.

The cutting head 12 is inserted into the longitudinal channel 3 of the boring bar 2 with a cylindrical pin 15. The longitudinal channel 3 is thereby closed at the end.

As can be seen in particular from Figures 3 and 4, several transverse bores 16, 17 are provided near the cutting head 12. These transverse bores 16, 17 connect the longitudinal channel 3 with the concavely rounded thread groove 5 of the circumferential profiling 4.

The longitudinal axes 18 of the transverse bores 16 extend obliquely from the longitudinal channel 3 in the direction of the cutting head 12, while the longitudinal axes 19 of the transverse bores 17 extend in the other direction. Furthermore, Figures 3 and 4 show that the longitudinal axes 18, 19 of the transverse bores 16, 17 extend in longitudinal planes 20 which intersect the longitudinal axis 21 of the longitudinal channel 3.

In the embodiment, the longitudinal axes 18, 19 of the transverse bores 16, 17 extend at an angle α of approximately 35° to the longitudinal axis 21 of the longitudinal channel 3.

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Reference symbol list

1 - Drilling anchor

2 - Boring bar v. 1

3 - Longitudinal channel in 2

4 - Profiling on 2

5 - Thread groove v. 4

6- Surface v. 4

7- Sleeve

8 - Surface of 7

9 - Interior of 7 10 - Ends of 7 11 - End of 1

12- Cutting head

13- Cutting edges

14 - Indentations on

15- Pin on 12

16- Cross holes

17- Transverse holes 18 - Longitudinal axes v.

19- Longitudinal axes of

20- Longitudinal planes of 18, 21 - Longitudinal axis of 3

22- Bridge of 4

Claims (10)

1. Drilling anchor, which has at least one longitudinally channeled drill rod ( 2 ) with a cutting head ( 12) closing its longitudinal channel (3 ) at the front and with a circumferential thread-like profiling ( 4 ) which is smaller in external diameter than the cutting head ( 12 ), which is connected to the longitudinal channel ( 3 ) by transverse bores ( 16 , 17 ) located near the cutting head (12), wherein the longitudinal axes ( 18 , 19 ) of the transverse bores ( 16 , 17 ), which extend partly from the longitudinal channel ( 3 ) obliquely in the direction of the cutting head ( 12 ) and partly obliquely in the other direction, are arranged in longitudinal planes ( 20 ) intersecting the longitudinal axis ( 21 ) of the longitudinal channel ( 3 ). 2. Drilling anchor according to claim 1, in which the longitudinal axes ( 18 , 19 ) of the transverse bores ( 16 , 17 ) extend at an angle of approximately 35° to the longitudinal axis ( 21 ) of the longitudinal channel ( 3 ). 3. Drilling anchor according to claim 1 or 2, in which the transverse bores ( 16 , 17 ) open into a concavely rounded thread groove ( 5 ) of the circumferentially cylindrical profiling ( 4 ). 4. Drilling anchor according to one of claims 1 to 3, in which the width (B) of the thread groove ( 5 ) of the profiling ( 4 ) is larger than the width (B1) of the web ( 22 ) of the profiling ( 4 ). 5. Drill anchor according to one of claims 1 to 4, in which the cutting head ( 12 ) is detachably or non-detachably connected to the drill rod ( 2 ). 6. Drilling anchor according to one of claims 1 to 5, in which the cutting head ( 12 ) is frustoconical. 7. Drill anchor according to one of claims 1 to 6, in which groove-like depressions ( 14 ) are provided on the circumference of the cutting head ( 12 ). 8. Drilling anchor according to one of claims 1 to 7, in which the cutting head ( 12 ) is fixed in the longitudinal channel ( 3 ) with a pin ( 15 ). 9. Drill anchor according to one of claims 1 to 8, in which the cutting head ( 12 ) is provided with cutting edges ( 13 ) ensuring an increased cutting force. 10. Drill anchor according to one of the protection claims 1 to 9, in which the drill rod ( 2 ) equipped with the cutting head ( 12 ) can be coupled in a tension- and compression-resistant manner to another drill rod ( 2) with longitudinal channels and a thread-like profile on the circumference via a sleeve (7 ) adapted to the profiling ( 4 ) on the inside ( 9 ).