EP0806543B1 - Drilling apparatus for percussive drilling - Google Patents

Abstract

The bore head with the hammer is connected to a bore rod and possibly at least to a flow channel axially running in the bore rod. The bore head (10) cross-sectionally narrows from a hammer-type end disc (26) to the chisel or bore point (28) in several stages (26,27, 27a-27g), whereby the stage edges determine a cone cover (K). The axial heights (b) of the stages and/or their width may be approximately of the same size. The stages can be determined by the crown arrangement, the pins of which are outwardly inclined in the advance direction. The ratio of the diameter of the end disc to the diameter of the chisel or bore point is preferable approximately 7:1.

Description

The invention relates to a drilling device for the percussive drilling by means of downhole hammer, especially for horizontal drilling according to the preamble of claims 1, 2.

The horizontal drilling technique with a so-called down-the-hole hammer increasingly used for drilling sewers. Here is a precise drilling - especially what the Vertical deviations affects - of particular importance. Since such holes are made in soils, the a very different and very changeable nature the drilling system must have the resulting Tendencies to deviate from the desired Take the drilling direction into account. Crucial for the exact Approaching the target point of the drilling can be done here Design of the drill head shape.

The generic DE-A-27 17 717 discloses a rock drill bit, whose drill face in work terraces which is resolved from the center of the drill to the edge of the Surround the drill face towards each other, with the working terraces run concentrically to each other; a central Pilot terrace is one or more recutting terraces surrounded, which are all coaxial to the drilling axis. The cutting pins point diagonally towards the latter arranged.

WO 9611323 A is also a concentric, terrace-like stepped boring head can be removed from its terraces project button-like elevations parallel to the axis, between which flush channels.

DE-A-43 26 000 describes a two-stage drill head for striking drilling of the type mentioned above; connects to a drilling disk with carbide pins a bolt-like pilot drill bit smaller in the direction of advance Diameter. In the circumference of the drilling disc Flushing grooves molded in and arranged in a spiral; your imaginary groove axes take opposite one Cone generating an angle greater than zero. In addition is the rear side in the direction of rotation of the drill head the flushing groove as a steep flank of a wing bridge trained one slope of another Wing bridge is opposite.

In particular for the underground laying of cables and Pipelines in boreholes from approximately 45 to 245 mm in displaceable soils are used so-called earth missiles; Indeed can neither with them in solid rock nor in soft Floors are worked. Drill lengths can be reached between ten and thirty meters, the drilling accuracy is about 2 to 4%. A tubular element with graduated Displacement head is horizontal from a launch gun like a tapered pile from an air powered one axially moving sliding piston in a vertical line Pit wall by compressed air with an average Driving speed of 1 m / h to 10 m / h driven. The direction of advance can, for example, by means of a the earth missile's built-in probe via a radio frequency signal observed from above - but not influenced - become. With changing floors, the drill heads can be in Adaptation to the soil conditions can be replaced - if the earth missile when entering the new soil type has not got stuck.

The inventor was aware of this state of the art the task, a directionally safe drilling method especially for creating shallow holes create that also in loose soil, sand or water-bearing Layers can be used.

The teaching of the independent leads to the solution of this task Claims; the subclaims give favorable designs on.

According to the invention the drill head is designed as an eccentric or provided with a tax slope. To form the eccentric is less than 180 ° part of the circumference covering a cross-section crescent-shaped formation and designed as a step. The crown trim can also be arranged asymmetrically.

Within the scope of the invention is a drill head in which the Cross section of the steps through a desk-like sloping surface of the drill head - the inside of its cone casing lies - is reduced on one side. This sloping surface lies approximately parallel to a generatrix of the cone shell.

In another version of the drill head, the Steps determined by the crown, whose pins are also Tilt outward in the direction of advance. The discharge of cuttings that cannot be displaced take place via Minutes of drilling that occur at each stage between the Carbide pins are located. This drill bit allows the Use in soil classes 5 to 7.

Has proven to be a cheap solution to the problem mentioned Ratio of the diameter of the end plate to the diameter the chisel or drill tip from 6: 1 to 8: 1 - preferably about 7: 1 - proven.

According to another feature of the invention is the end plate - against the direction of advance - with a connecting plate shorter diameter due to an annular desk surface connected; the inclination of the desk surface preferably corresponds about the inclination of the carbide pins. It serves for Exhausting the down-the-hole exhaust. This supports the Displacement drilling head the solidification of the bore wall as well as the drill material discharge for the carbide-tipped drill head non-displaceable drill bits.

To enable a direction correction on the drill head, is the downhole hammer a radio transmitter of an external Assigned to the location system. Through the described Drilling heads are created in connection with location systems - Radio transmitter in the drilling tool and carrying the Radio receiver - a controllable drilling system.

The drill head with the down-the-hole hammer - with simultaneous rotation - introduced. By Interruption of rotation can cause the hole to run over the position of the control slopes or the eccentric to be influenced. The position of the tax slope is from Station displayed. After the correction, the Rotation activated again.

The displacement drilling head according to the invention for down-the-mill hammers a drilling diameter of 80 to 300 mm can - depending on Down-the-hole hammer size - used up to floor class 6; this drilling system can usually with short Earth rockets used in displaceable soils replace.

In contrast to earth missiles, the system is also in Loose soil, sand or water-bearing layers can be used because the down-the-hole hammer has a stiff Drill pipe is connected to the drill and with a Driving force of up to 850 KN can be injected. This feed force supports the powerful blows of the Percussion piston of the down-the-hole hammer, which the Displacing displacement core in the ground; thereby the rate of advance as well as the achievable Propulsion length is positively influenced.

Due to the rotation of the drilling tool and the stiff Linkage is - especially with non-uniform Soils - given a much better target accuracy, and there will be significantly longer tunnel lengths as well as longer ones Propulsion speeds reached than with the earth rocket; the rotary movement of the drill head supports the rearrangement Earth components to be displaced such as rubble, stones, gravel and sand.

It is within the scope of the invention that the invention Drilling device replaced the above-mentioned rocket.

Fig. 1, 4:

teilweise geschnittene Seitenansichten jeweils eines Verdrängerbohrkopfes für einen Imlochhammer an einem Bohrgestänge;

Fig. 2, 5:

die Stirnansicht zu Fig. 1 bzw. Fig. 4;

Fig. 3, 6, 8:

teilweise geschnittene Seitenansichten anderer Ausgestaltungen eines Verdrängerbohrkopfes;

Fig. 7, 9:

die Stirnansicht zu Fig. 6 bzw. Fig. 8;

Further advantages, features and details of the invention result from the following description of preferred exemplary embodiments and from the drawing; this shows in

1, 4:

partially sectioned side views each of a displacement drill head for a down-the-hole hammer on a drill pipe;

2, 5:

the front view of Fig. 1 and Fig. 4;

3, 6, 8:

partially sectioned side views of other configurations of a displacement drill head;

7, 9:

the front view of Fig. 6 and Fig. 8;

A displacement boring head 10 is shown in FIG. 1 below Interposition of a tubular retaining cap 12 at the end at one - with the housing 14 one in particular not shown downhole hammer 16 for striking horizontal drilling connected - receiving shaft 18 with spline profile 20. The housing 14 closes against the direction of advance x one by means of a threaded or hexagon connection 21 axially fixed rigid drill pipe 22, whichever can be extended.

This displaceable drilling head 10, which can be used for bore diameters between 80 and 300 mm up to soil class 6, is connected to the down-hole hammer 16 via the tubular retaining cap 12 on a connecting plate 24 and tapers in a longitudinal section stepwise from an end plate 26 via here eight step plates 27, 27 _a to 27 _g , the number of which depends on the drill head diameter d, to a chisel tip 28. The disks 26, 27, 27 _a to 27 _g are parts of a one-piece crown body, that is to say molded onto one another, and their edges determine a construction cone, of which a generating line K is shown. Its cone tip defines an angle of approximately 40 °.

The axial height a of the end plate 26 corresponds to the axial heights b of the step plates 27, 27 _a to 27 _g . The nine radial step widths i are the same and reduce the diameter d of the end plate 26 to the diameter n of the drill tip 28 in an example ratio of 7: 1. For larger drill diameters, the number of steps, step width i and step height a can change.

Fig. 3 shows a drill head 10 _a , which is populated with hard metal pins 30; these form - here three - levels. The axes B of the hard metal pins 30 are inclined at an angle of approximately 33 ° to the drill head axis A. An air duct 32 runs in this, from which both a front duct 33 of smaller diameter axially and side ducts 34, which are inclined against the direction of advance x, extend. The latter open into an annular console surface 36 which in turn is inclined towards the direction of advance x and serve to discharge the down-the-hole hammer air while at the same time supporting the discharge of non-displaceable cuttings.

4, 5 is cross-sectional asymmetrical.

The end plate 26 _a is here - compared to that of Figures 1-- of double axial height a; From this end disk 26 _a a crescent-like apex step 38 is formed, the radial step width i of which is continuously reduced on both sides of a line of symmetry G of the drill head cross-section up to a parallel Q which intersects the line of symmetry G at right angles to a horizontal straight line D in FIG. 5 ; whose distance t from that parallel Q corresponds approximately to the step width i.

In this drill head 11, the down-the-hole hammer 16 is used for Straight ahead with simultaneous rotation. In the event of an interruption the course of the rotation can be determined by the rotational movement the setting of the eccentric described are influenced. For this purpose, the radio transmitter 40 of a location system is in the drilling tool housed - the radio receiver becomes during the day carried and shows except the position of the eccentric - or a tax inclined surface to be discussed - also the inclination and depth of the downhole hammer 16.

4, both the axial air duct 32 and a Continuing axially offset air duct 42 dashed hinted at; the latter runs outside of that Radio transmitter 40.

The displacement boring head 11 _a of FIGS. 6, 7 is equipped with a control inclined surface 44 starting from the end plate 26; the latter appears in the side view of FIG. 6 as a straight line which is inclined at an angle w of approximately 22 ° to the drill head axis A and which intersects 27 _g in the region of the front step disc. This straight line lies within the conical jacket K described in FIG. 1. The control inclined surface 44 here assumes the function described above for the position of the eccentric.

8, 9 show a likewise unsymmetrical displacement boring head _11b ; to the largest cross-section of three circular stepped washers 27 _a to 27 _c is also followed by a crescent-like vertex step 38 above the horizontal straight line D in FIG. 9, which in this embodiment ends at drilling minutes 46 of the integrally formed stepped washer 27 _a . The diameter line standing perpendicular to the horizontal diameter line D also forms a line of symmetry G for the stepped washers here - but not with regard to the stocking of hard metal pins 30. These are additionally present in both the drilling tip 28 and in the stepped washer 27 _c adjacent to it - due to the from the center of the bore M determined by the center point M - provided diagonals E.

The drilling head 11b serves on the one hand in the manner described Influencing the straight line. On the other hand, he commutes with direction correction up to approximately ± 60 ° around the respective correction axis.

Claims (12)

1. Drilling apparatus for percussive drilling with an inhole hammer, in particular for horizontal drilling, with a drill head (10, 10_a, 11, 11_a, 11_b) which tapers several times in steps (26, 27, 27_a to 27_g) cross-sectionally from an end plate (26) on the hammer side to the chisel or bit (28) as well as with a crown of hard metal pins or the like arranged on at least one end face, wherein the step edges define a cone envelope (K) and the drill head with the in-hole hammer is connected to a drill string and if occasion arises at least one flow channel extending axially therein, characterised in that an attachment (38) of crescent-shaped cross section is laid around a portion of the circumference covering less than 180° and constructed as a step.
2. Drilling apparatus for percussive drilling with an in-hole hammer, in particular for horizontal drilling, with a drill head (10, 10_a, 11, 11_a, 11_b) which tapers several times in steps (26, 27, 27_a to 27_g) cross-sectionally from an end plate (26) on the hammer side to the chisel or bit (28) as well as with a crown of hard metal pins or the like arranged on at least one end face, wherein the step edges define a cone envelope (K) and the drill head with the in-hole hammer is connected to a drill string and if occasion arises at least one flow channel extending axially therein, characterised in that the cross-section of the steps (26, 27, 27_a to 27_g) is reduced on one side by a step-like inclined surface (44) of the drill head (11_a) which is located within its cone envelope (K).
3. Drilling apparatus according to claim 1, characterised in that the crescent-shaped attachment (38) adjoins at each of the two ends a drilling groove (46).
4. Drilling apparatus according to claim 2, characterised in that the inclined surface (44) lies parallel to a generatrix of the cone envelope (K).
5. Drilling apparatus according to claim 1 or 2, characterised in that the steps (26, 27, 27_a to 27_g) are defined by the crown whose pins (30) are also inclined outwardly in the direction of advance (x).
6. Drilling apparatus according to any of claims 1 to 5, characterised by a ratio of the diameter (d) of the end plate (26) to the diameter (n) of the chisel or bit of about 7 : 1 to 8 : 1.
7. Drilling apparatus according to any of claims 1 to 6, characterised in that the number of steps (26, 27, 27_a to 27_g) increases with an increase in the bore diameter.
8. Drilling apparatus according to claims 1, 2 or 7, characterised by nine steps (26, 27, 27_a to 27_g) in front of the chisel or bit (28).
9. Drilling apparatus according to either of claims 1 to 2, characterised in that the end plate (26) in the direction opposite the direction of advance (x) is connected to a connecting plate (24) of shorter diameter by an annular step surface (36).
10. Drilling apparatus according to claims 5 and 9, characterised in that the inclination of the step surface (36) roughly corresponds to the inclination of the hard metal pins (30).
11. Drilling apparatus according to one or more of claims 1 to 10, characterised in that a radio transmitter (40) of an external position finding system is associated with the in-hole drill hammer (16) and/or it is constructed as an eccentric.
12. Drilling apparatus according to one or more of claims 1 to 11, characterised in that the crown (30) is arranged asymmetrically.

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