EP0799966A2 - Drill bit for percussive drilling - Google Patents

Drill bit for percussive drilling Download PDF

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Publication number
EP0799966A2
EP0799966A2 EP97104925A EP97104925A EP0799966A2 EP 0799966 A2 EP0799966 A2 EP 0799966A2 EP 97104925 A EP97104925 A EP 97104925A EP 97104925 A EP97104925 A EP 97104925A EP 0799966 A2 EP0799966 A2 EP 0799966A2
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EP
European Patent Office
Prior art keywords
drill bit
drilling
disc
drill
disk
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP97104925A
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German (de)
French (fr)
Other versions
EP0799966A3 (en
Inventor
Jürgen Dipl.-Ing. Schmeer
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GEISERT ENGINEERING GmbH
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GEISERT ENGINEERING GmbH
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from DE19619194A external-priority patent/DE19619194A1/en
Application filed by GEISERT ENGINEERING GmbH filed Critical GEISERT ENGINEERING GmbH
Publication of EP0799966A2 publication Critical patent/EP0799966A2/en
Publication of EP0799966A3 publication Critical patent/EP0799966A3/en
Withdrawn legal-status Critical Current

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    • E—FIXED CONSTRUCTIONS
    • E21—EARTH OR ROCK DRILLING; MINING
    • E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
    • E21B10/00—Drill bits
    • E21B10/36—Percussion drill bits
    • E21B10/40—Percussion drill bits with leading portion
    • E—FIXED CONSTRUCTIONS
    • E21—EARTH OR ROCK DRILLING; MINING
    • E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
    • E21B10/00—Drill bits
    • E21B10/36—Percussion drill bits
    • E21B10/38—Percussion drill bits characterised by conduits or nozzles for drilling fluids
    • E—FIXED CONSTRUCTIONS
    • E21—EARTH OR ROCK DRILLING; MINING
    • E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
    • E21B17/00—Drilling rods or pipes; Flexible drill strings; Kellies; Drill collars; Sucker rods; Cables; Casings; Tubings
    • E21B17/02—Couplings; joints
    • E21B17/04—Couplings; joints between rod or the like and bit or between rod and rod or the like
    • E21B17/07—Telescoping joints for varying drill string lengths; Shock absorbers
    • E21B17/076—Telescoping joints for varying drill string lengths; Shock absorbers between rod or pipe and drill bit

Definitions

  • the invention relates to a drill bit for striking horizontal drilling by means of an in-hole hammer with a crown covering arranged on an end face - in particular made of hard metal pins - and with flushing passages arranged at a distance from the drill bit axis on a drill disk of the drill bit.
  • the end face thereof can have a central section crossing the drill bit axis with an outwardly adjoining conical ring section which is inclined to a peripheral surface of the drill disk.
  • the horizontal drilling technique with a so-called down-the-hole hammer is increasingly used for drilling sewers.
  • precise drilling - especially with regard to vertical deviations - is of particular importance. Since such bores are made in soils that can have a very different and very changeable nature, the drilling system must take into account the resulting tendencies to deviate from the desired drilling direction. The design of the crown shape can be decisive for reaching the target point of the bore.
  • a drill bit for impact drilling of the type mentioned in which to increase the directional stabilization to a central section of the end face transverse to the drill bit axis, a conical ring section connects, the radius of which corresponds to more than twice the radius of the central section at a cone angle with the drill bit axis of approximately 50 to 70 °.
  • Flushing grooves molded into the circumference of the drilling disk serve as flushing passages.
  • the flushing grooves are arranged in a spiral, and their imaginary groove axes form an angle greater than zero with respect to a cone-generating line.
  • this flushing groove in the direction of rotation of the drill bit is designed as a steep flank of a wing web, opposite an inclined flank of another wing bridge.
  • this flushing groove consists of a cylindrical partial surface and two adjoining flat surfaces, both of which enclose an angle of 90 °.
  • Flushing grooves for the drill cuttings discharge on the outer circumference of the drill bit cut slightly downwards in soft to medium-strength rock and on soils with different characteristics during horizontal drilling, at the same time the cuttings are blown against the borehole wall, which in the case of small-grained cuttings blows the space between the borehole wall and what has to be carried along Protective or jacket pipe leads. This allows the pipes to get stuck after just a few drilling meters. This can only be avoided by a relatively large advance of the drill bit to the protective tube, which in turn increases the risk of stone falling between the drill bit and the protective tube.
  • the inventor has set the goal of improving a drilling bit of the type mentioned at the outset with regard to its rinsing behavior and increasing the accuracy of the drilling process.
  • the flushing passages are formed by —bore-like — flushing channels which run within the drilling disc in the sand to the peripheral surface thereof. Thanks to this requirement, any existing cuttings are discharged through these holes in the crown body. The circumferential surface of the drill bit is closed and therefore does not affect the borehole wall. The cuttings are blown directly into the protective or jacket pipe carried along and cannot block the annular gap between the borehole wall and the jacket pipe.
  • the drill bit can be arranged very close to the casing tube; it runs very smoothly during horizontal drilling, since the closed flushing holes do not get caught on the wall of the borehole. This minimizes wear on the end of the hammer drill, on the socket or crown shaft and on the drill drive.
  • the flushing channels are arranged at the transition from the central section to the conical ring section of the end face, preferably also at the transition from a central section of the back or lower surface of the drilling disc to the subsequent conical ring section of this back or underside.
  • the latter is inclined in the opposite direction to the conical ring section of the end face.
  • the conical shoulder or conical ring section of the drilling disc is kept narrow in order to avoid displacing soft soil components, for example in loamy soil with stone deposits during the drilling. Thanks to this requirement, the complete bore cross-section is cleared and at the same time it is prevented that displaced soil can relax again just behind the drill bit and the slight overcut in the form of the annular gap between the borehole wall and the casing pipe can be filled.
  • radial inner grooves extending from the mouth of the rinsing channels to the longitudinal axis of the drill bit can be provided in the end face of the drilling disc, which lead to better drilling material discharge.
  • the drill bit can be attached to the receiving shaft in a manner known per se by means of a conical seat. This is only suitable for use with a small hole hammer (3 "-6"). In the case of larger hammers (5 “-12"), the cone seat is replaced according to the invention by a feather key, splined shaft or threaded connection, since otherwise the drill bit disc can tear due to the wedge action of the shaft with high impact energy.
  • Another significant advantage of the parallel key or splined shaft connection is the ability to mount the drill bit disc in a defined manner; Both the drilling disc and an axially protruding pre-drill can be supplied with purging air directly. The better flushing leads to faster drilling material discharge and thus to greater drilling progress and less tool wear.
  • a borehole 12 is made in a soil or rock formation 10 by means of a horizontal drilling system - for a diameter range between 180 mm and 840 mm; the longitudinal axis A of a drill bit 14 engaging in the formation 10 runs horizontally in FIG. 1.
  • a receiving shaft 16 with a spline profile 18 of the drill bit 14 is connected against the direction of advance x by a hammer overtube 20 with an external helix 22, which receives a single-hole hammer 24, neglected for the sake of drilling, for reasons of clarity in the drawing.
  • the hammer overtube 20 and a drill rod 26 axially fixed to the down-the-hole hammer 24 by means of a threaded or hexagonal connection 25 are encompassed by a protective or jacket tube 28, the front edge 29 of which is assigned to a collar 32 screwed to an external thread 30 of the drill bit 14.
  • a narrow annular gap 34 runs between the casing tube 28 and the borehole wall 11.
  • the outer diameter d of the sleeve 32 corresponds to that of the outer edge 23 of the overtube coil 22.
  • the helix diameter may be somewhat reduced for reasons of friction.
  • a drill disk 36 is seated on the receiving shaft 16 toward the deepest of the borehole, the outer diameter e iw of which determines the borehole width.
  • a pin-like pilot drill bit 38 projects axially from this drill disk 36, which is designed like a ring in the area of the outer diameter e; the outer diameter e of the drilling disk 36 measures approximately 2.5 times the outer diameter i of the pilot drill bit 38. Its free collar length h corresponds to approximately half the drill bit length h 1 .
  • the end face 40 of the drilling disk 36 is composed of a circular central section 40 z of diameter n, which crosses the drill bit axis A at right angles, and a narrow conical ring section 40 k , which includes a flat cone angle w with the drill bit axis A.
  • the conical ring section 40 k - and thus the end face 40 - ends on a circumferential surface 42 of the drilling disk 36, which widens in the direction of advance x; it includes an angle t of 3 ° to 5 ° with the drill bit axis A.
  • the end face 40 of the drilling disk 36 like the end face 39 of the pilot drill bit 38, is covered with hard metal pins 44.
  • Rinsing channels 46 which are approximately axially parallel and which penetrate the drilling disk 36, emanate from the end face 40 at a radial distance z from the peripheral face 42; their diameter q corresponds to approximately one sixth of the largest outer diameter e of the drill bit 14.
  • the flushing channels 46 open out at the back or underside 48 of the drilling disk 36. This underside 48 is designed like the end face 40; an inner cone section 48 z is adjoined by an outer cone section 48 k .
  • the central axis M of the flushing channel 46 runs approximately through a construction circle K separating these sections 40 k , 40 z or 48 k , 48 z .
  • blind bores 50 of the drilling disk 36 can be seen on its peripheral surface 42. These blind bores 50 receive hard metal pins 44, which serve the circumferential surface 42 as wear protection. 3, 5 shown radial inner grooves 52 in the central portion 40 z of the end face 40 improve the drilling material discharge.
  • the receiving shaft 16 which offers the spline profile 18 described above is seated in the drill bit 14 of FIGS. 2, 3 by means of a conical ring 54 tapering in the direction of advance x, to which a thread (not shown) for the pre-drill bit 38 can be connected.
  • 5 of the shank is provided with a collar 56 16 which engages in an annular shoulder 58 of the Bohra 36 a.
  • the bearing section 16 a adjoining the feed direction x is secured against rotation by parallel keys 60.
  • the axial grooves for this on the drill head side are designated by 62 in FIG. 5.
  • connection between the mounting shaft 16 and the drilling disk 36 by means of a toothed shaft connection or a threaded connection is not shown.
  • Round material can no longer be used to produce large drill bits 14 with a diameter e between 500 mm and 840 mm; in this case, forging blanks must be used, from which the drilling disk 36, the receiving shaft 16 and the pilot drill 38 are then produced in one piece in a cost-effective manner.

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  • Engineering & Computer Science (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Geology (AREA)
  • Mining & Mineral Resources (AREA)
  • Mechanical Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Environmental & Geological Engineering (AREA)
  • Fluid Mechanics (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • Geochemistry & Mineralogy (AREA)
  • Earth Drilling (AREA)

Abstract

The drill bit comprises front end cutters, especially hard metal tips, and axially offset mud passages in a drilling disc of the bit. The passages are formed by channels (46) within the disc (36) at spaced (z) from its circumferential surface (42). The bit may have a front end central section, and an adjoining conical ring section, which extends outwards and which slopes towards and merges into the circumferential surface of the disc. The channels (46) can be located at the junction between the central section (40z) and the conical ring section (40k). When the bit has a holder shaft for the disc and, optionally, a stub-like axial initial drilling bit, the holder shaft (16) may be either supported on the disc (36) by an annular collar, in which it is held by tongues, or held in the disc (36) by a toothed or threaded joint.

Description

Die Erfindung betrifft eine Bohrkrone für das schlagende Horizontalbohren mittels Imlochhammers mit an einer Stirnfläche angeordnetem Kronenbesatz -- insbesondere aus Hartmetallstiften -- sowie mit in Abstand zur Bohrkronenachse angeordneten Spüldurchgängen an einer Bohrscheibe der Bohrkrone. Deren Stirnfläche kann einen die Bohrkronenachse querenden Zentralabschnitt mit nach außen anschließendem Kegelringabschnitt aufweisen, der zu einer Umfangsfläche der Bohrscheibe geneigt ist.The invention relates to a drill bit for striking horizontal drilling by means of an in-hole hammer with a crown covering arranged on an end face - in particular made of hard metal pins - and with flushing passages arranged at a distance from the drill bit axis on a drill disk of the drill bit. The end face thereof can have a central section crossing the drill bit axis with an outwardly adjoining conical ring section which is inclined to a peripheral surface of the drill disk.

Die Horizontalbohrtechnik mit einem sog. Imlochhammer wird verstärkt für das Bohren von Abwasserkanälen eingesetzt. Hierbei ist ein zielgenaues Bohren -- insbesondere was die Vertikalabweichungen betrifft -- von besonderer Bedeutung. Da derartige Bohrungen in Böden vorgenommen werden, die eine sehr unterschiedliche und sehr wechselhafte Beschaffenheit aufweisen können, muß das Bohrsystem die daraus resultierenden Neigungen zur Abweichung von der gewünschten Bohrrichtung berücksichtigen. Entscheidend zum Erreichen des Zielpunktes der Bohrung kann hierbei die Ausgestaltung der Kronenform sein.The horizontal drilling technique with a so-called down-the-hole hammer is increasingly used for drilling sewers. Here, precise drilling - especially with regard to vertical deviations - is of particular importance. Since such bores are made in soils that can have a very different and very changeable nature, the drilling system must take into account the resulting tendencies to deviate from the desired drilling direction. The design of the crown shape can be decisive for reaching the target point of the bore.

Durch die DE-A-43 26 000 ist eine Bohrkrone für schlagendes Bohren der eingangs genannten Art bekannt geworden, bei der zur Erhöhung der Richtungsstabilisierung an einen die Bohrkronenachse querenden Zentralabschnitt der Stirnfläche ein Kegelringabschnitt anschließt, dessen Radius mehr als dem zweifachen Radius des Zentralabschnittes entspricht bei einem Konuswinkel mit der Bohrkronenachse von etwa 50 bis 70°. Als Spüldurchgänge dienen in den Bohrscheibenumfang eingeformte Spülnuten. Die Spülnuten sind spiralartig angeordnet, und ihre gedachten Nutenachsen nehmen gegenüber einer Kegelerzeugenden einen Winkel größer null ein. Zudem ist die jeweils in Drehrichtung der Bohrkrone hintere Seite der Spülnut als steile Flanke eines Flügelsteges ausgebildet, der eine geneigte Flanke eines anderen Flügelsteges gegenüberliegt. Insgesamt besteht diese Spülnut aus einer zylindrischen Teilfläche und zwei anschließenden ebenen Flächen, die beide einen Winkel von 90° einschließen.From DE-A-43 26 000 a drill bit for impact drilling of the type mentioned is known, in which to increase the directional stabilization to a central section of the end face transverse to the drill bit axis, a conical ring section connects, the radius of which corresponds to more than twice the radius of the central section at a cone angle with the drill bit axis of approximately 50 to 70 °. Flushing grooves molded into the circumference of the drilling disk serve as flushing passages. The flushing grooves are arranged in a spiral, and their imaginary groove axes form an angle greater than zero with respect to a cone-generating line. In addition, the rear side of the flushing groove in the direction of rotation of the drill bit is designed as a steep flank of a wing web, opposite an inclined flank of another wing bridge. Overall, this flushing groove consists of a cylindrical partial surface and two adjoining flat surfaces, both of which enclose an angle of 90 °.

Spülnuten für den Bohrkleinaustrag am äußeren Umfang der Bohrkrone fräsen sich bei weichem bis mittelfestem Gestein sowie bei Böden mit unterschiedlicher Beschaffenheit während des Horizontalbohrens leicht nach unten, gleichzeitig wird das Bohrklein gegen die Bohrlochwand geblasen, was bei kleinkörnigem Bohrklein zum Verblasen des Zwischenraums zwischen Bohrlochwand und mitzuführendem Schutz- bzw. Mantelrohr führt. Dadurch können sich die Rohre schon nach wenigen Bohrmetern festfahren. Dies ist nur durch einen relativ großen Vorlauf der Bohrkrone zum Schutzrohr zu vermeiden, wodurch jedoch wiederum die Gefahr von Steinfall zwischen Bohrkrone und Schutzrohr zunimmt.Flushing grooves for the drill cuttings discharge on the outer circumference of the drill bit cut slightly downwards in soft to medium-strength rock and on soils with different characteristics during horizontal drilling, at the same time the cuttings are blown against the borehole wall, which in the case of small-grained cuttings blows the space between the borehole wall and what has to be carried along Protective or jacket pipe leads. This allows the pipes to get stuck after just a few drilling meters. This can only be avoided by a relatively large advance of the drill bit to the protective tube, which in turn increases the risk of stone falling between the drill bit and the protective tube.

In Kenntnis dieses Standes der Technik hat sich der Erfinder das Ziel gesetzt, eine Bohrkrone der eingangs erwähnten Art bezüglich ihres Spülverhaltens zu verbessern sowie die Genauigkeit des Bohrvorganges zu erhöhen.Knowing this state of the art, the inventor has set the goal of improving a drilling bit of the type mentioned at the outset with regard to its rinsing behavior and increasing the accuracy of the drilling process.

Zur Lösung dieser Aufgabe führt die Lehre des unabhängigen Anspruches; die Unteransprüche geben günstige Weiterbildungen an.The teaching of the independent claim leads to the solution of this task; the subclaims indicate favorable further training.

Erfindungsgemäß werden die Spüldurchgänge von -- bohrungsartigen -- Spülkanälen gebildet, die innerhalb der Bohrscheibe in Absand zu deren Umfangsfläche verlaufen. Dank dieser Maßgabe wird anstehendes Bohrklein durch diese Bohrungen im Kronenkörper abgeführt. Die Umfangsfläche der Bohrkrone ist geschlossen und beeinflußt somit die Bohrlochwand nicht. Das Bohrklein wird direkt in das mitgeführte Schutz- oder Mantelrohr geblasen und kann nicht den Ringspalt zwischen Bohrlochwandung und Mantelrohr verdämmen.According to the invention, the flushing passages are formed by —bore-like — flushing channels which run within the drilling disc in the sand to the peripheral surface thereof. Thanks to this requirement, any existing cuttings are discharged through these holes in the crown body. The circumferential surface of the drill bit is closed and therefore does not affect the borehole wall. The cuttings are blown directly into the protective or jacket pipe carried along and cannot block the annular gap between the borehole wall and the jacket pipe.

Als weiterer Vorteil ist anzusehen, daß die Bohrkrone sehr nahe vor dem Mantelrohr angeordnet sein kann; sie läuft während des Horizontalbohrens sehr ruhig, da sich die geschlossenen Spülbohrungen an der Bohrlochwandung nicht verhaken. Hierdurch wird der Verschleiß beim Bohrhammereinsteckende, am Aufnahme- oder Kronenschaft sowie am Bohrantrieb minimiert.Another advantage is that the drill bit can be arranged very close to the casing tube; it runs very smoothly during horizontal drilling, since the closed flushing holes do not get caught on the wall of the borehole. This minimizes wear on the end of the hammer drill, on the socket or crown shaft and on the drill drive.

Nach anderen Merkmalen der Erfindung sind die Spülkanäle am Übergang vom Zentralabschnitt zum Kegelringabschnitt der Stirnfläche angeordnet, bevorzugt auch am Übergang von einem Zentralabschnitt der Rücken- oder Unterfläche der Bohrscheibe zum anschließenden Kegelringabschnitt dieser Rücken- oder Unterseite. Letzterer ist gegenläufig zum Kegelringabschnitt der Stirnfläche geneigt.According to other features of the invention, the flushing channels are arranged at the transition from the central section to the conical ring section of the end face, preferably also at the transition from a central section of the back or lower surface of the drilling disc to the subsequent conical ring section of this back or underside. The latter is inclined in the opposite direction to the conical ring section of the end face.

Der Kegelansatz oder Kegelringabschnitt der Bohrscheibe ist schmal gehalten, um ein Verdrängen weicher Bodenbestandteile beispielsweise in lehmigem Boden mit Steineinlagerungen während der Bohrung zu vermeiden. Dank dieser Maßgabe wird der komplette Bohrungsguerschnitt geräumt und gleichzeitig verhindert, daß sich verdrängter Boden kurz hinter der Bohrkrone wieder entspannen sowie den geringen Überschnitt in Form des Ringspaltes zwischen Bohrlochwand und Mantelrohr verfüllen kann.The conical shoulder or conical ring section of the drilling disc is kept narrow in order to avoid displacing soft soil components, for example in loamy soil with stone deposits during the drilling. Thanks to this requirement, the complete bore cross-section is cleared and at the same time it is prevented that displaced soil can relax again just behind the drill bit and the slight overcut in the form of the annular gap between the borehole wall and the casing pipe can be filled.

Zudem hat es sich als günstig erwiesen, die kranzartig vorgesehenen Spülkanäle so anzuordnen, daß ihre Mittelachsen etwa parallel zur Bohrkronenlängsachse verlaufen.In addition, it has proven advantageous to arrange the rinsing channels provided in the manner of a ring so that their central axes run approximately parallel to the longitudinal axis of the drill bit.

Erfindungsgemäß können in der Stirnfläche der Bohrscheibe von der Mündung der Spülkanäle zur Bohrkronenlängsachse verlaufende radiale Innennuten vorgesehen sein, die zu einem besseren Bohrgutaustrag führen.According to the invention, radial inner grooves extending from the mouth of the rinsing channels to the longitudinal axis of the drill bit can be provided in the end face of the drilling disc, which lead to better drilling material discharge.

Die Bohrkrone kann am Aufnahmeschaft in an sich bekannter Weise durch einen Konussitz angebracht sein. Dieser ist nur für den Kroneneinsatz mit kleinen Imlochhämmern (3"-6") geeignet. Bei größeren Hämmern (5"-12") wird der Konussitz erfindungsgemäß durch eine Paßfeder, Zahnwellen- oder Gewindeverbindung ersetzt, da ansonsten die Bohrkronenscheibe durch die Keilwirkung des Schaftes bei hoher Schlagenergie reißen kann. Ein weiterer wesentlicher Vorteil der Paßfeder- oder Zahnwellenverbindung liegt in der Möglichkeit, die Bohrkronenscheibe definiert zu montieren; sowohl die Bohrscheibe als auch ein axial von ihr abragender Vorbohrer können direkt mit Spülluft beaufschlagt werden. Die bessere Spülung führt zu schnellem Bohrgutaustrag und somit zu einem größeren Bohrfortschritt und zu geringerem Werkzeugverschleiß.The drill bit can be attached to the receiving shaft in a manner known per se by means of a conical seat. This is only suitable for use with a small hole hammer (3 "-6"). In the case of larger hammers (5 "-12"), the cone seat is replaced according to the invention by a feather key, splined shaft or threaded connection, since otherwise the drill bit disc can tear due to the wedge action of the shaft with high impact energy. Another significant advantage of the parallel key or splined shaft connection is the ability to mount the drill bit disc in a defined manner; Both the drilling disc and an axially protruding pre-drill can be supplied with purging air directly. The better flushing leads to faster drilling material discharge and thus to greater drilling progress and less tool wear.

Bei inhomogenen Gesteinsformationen besteht die Gefahr, daß sich durch die Vibration der Bohrkrone während des Bohrvorganges Gesteinsbrocken aus der Bohrlochwand lösen und in den Freiraum zwischen Bohrkrone und Mantelrohr fallen. Dadurch wird das ganze System blockiert und kann unter Umständen nicht mehr geborgen werden.In the case of inhomogeneous rock formations, there is a risk that rocks will loosen from the borehole wall due to the vibration of the drill bit during the drilling process and fall into the space between the drill bit and the casing. This blocks the entire system and may no longer be able to be recovered.

Diese Gefahr besteht nicht mehr, wenn die Bohrkronenscheibe erfindungsgemäß durch ein aufgeschraubtes Zwischenrohr, eine Manschette, ergänzt wird; hierdurch entsteht ein geschlossenes, störungsunanfälliges System.This danger no longer exists if, according to the invention, the drill bit disc is supplemented by a screwed-on intermediate tube, a sleeve; this creates a closed, trouble-free system.

Weitere Vorteile, Merkmale und Einzelheiten der Erfindung ergeben sich aus der nachfolgenden Beschreibung bevorzugter Ausführungsbeispiele sowie anhand der Zeichnung; diese zeigt in

Fig. 1:
die teilweise geschnittene Seitenansicht eines Horizontalbohrers mit Bohrkrone in einem Bohrloch;
Fig. 2, 4:
die vergrößerten Seitenansichten zweier teilweise geschnittener Ausgestaltungen der Bohrkrone;
Fig. 3, 5:
stirnwärtige Draufsichten auf die Bohrkronen der Fig. 2 bzw. 4.
Further advantages, features and details of the invention result from the following description of preferred exemplary embodiments and from the drawing; this shows in
Fig. 1:
the partially sectioned side view of a horizontal drill with drill bit in a borehole;
2, 4:
the enlarged side views of two partially cut configurations of the drill bit;
3, 5:
frontal top views of the drill bits of FIGS. 2 and 4.

In einer Boden- oder Gesteinsformation 10 ist ein Bohrloch 12 mittels eines Horizontalbohrsystems -- für einen Durchmesserbereich zwischen 180 mm und 840 mm -- eingebracht; die Längsachse A einer in die Formation 10 eingreifenden Bohrkrone 14 verläuft in Fig. 1 horizontal. An einen Aufnahmeschaft 16 mit Keilwellenprofil 18 der Bohrkrone 14 schließt gegen die Vortriebsrichtung x ein Hammerüberrohr 20 mit außenliegender Wendel 22 an, das einen aus Gründen der Übersichtlichkeit in der Zeichnung im einzelnen vernachlässigten Imlochhammer 24 zum schlagenden Bohren aufnimmt.A borehole 12 is made in a soil or rock formation 10 by means of a horizontal drilling system - for a diameter range between 180 mm and 840 mm; the longitudinal axis A of a drill bit 14 engaging in the formation 10 runs horizontally in FIG. 1. A receiving shaft 16 with a spline profile 18 of the drill bit 14 is connected against the direction of advance x by a hammer overtube 20 with an external helix 22, which receives a single-hole hammer 24, neglected for the sake of drilling, for reasons of clarity in the drawing.

Das Hammerüberrohr 20 und ein am Imlochhammer 24 durch eine Gewinde- oder eine Sechskantverbindung 25 axial festgelegtes Bohrgestänge 26 werden von einem Schutz- oder Mantelrohr 28 umfangen, dessen Frontkante 29 einer an einem Außengewinde 30 der Bohrkrone 14 verschraubten Manschette 32 zugeordnet ist. Zwischen dem Mantelrohr 28 und der Bohrlochwandung 11 verläuft ein schmaler Ringspalt 34. Der Außendurchmesser d der Manschette 32 entspricht jenem der Außenkante 23 der Überrohrwendel 22. Bei einer Gestängewendel 22a am Bohrgestänge 26 kann der Wendeldurchmesser aus Gründen der Reibung etwas reduziert sein.The hammer overtube 20 and a drill rod 26 axially fixed to the down-the-hole hammer 24 by means of a threaded or hexagonal connection 25 are encompassed by a protective or jacket tube 28, the front edge 29 of which is assigned to a collar 32 screwed to an external thread 30 of the drill bit 14. A narrow annular gap 34 runs between the casing tube 28 and the borehole wall 11. The outer diameter d of the sleeve 32 corresponds to that of the outer edge 23 of the overtube coil 22. In the case of a rod coil 22 a on the drill pipe 26, the helix diameter may be somewhat reduced for reasons of friction.

Am Aufnahmeschaft 16 sitzt zum Bohrlochtiefsten hin eine Bohrscheibe 36, deren Außendurchmesser e i.w. die Bohrlochweite bestimmt. Von dieser im Bereich des Außendurchmessers e kranzartig ausgebildeten Bohrscheibe 36 ragt axial eine bolzenartige Vorbohrkrone 38 ab; der Außendurchmesser e der Bohrscheibe 36 mißt etwa das 2,5-fache des Außendurchmessers i der Vorbohrkrone 38. Deren freie Kraglänge h entspricht etwa der halben Bohrkronenlänge h1.A drill disk 36 is seated on the receiving shaft 16 toward the deepest of the borehole, the outer diameter e iw of which determines the borehole width. A pin-like pilot drill bit 38 projects axially from this drill disk 36, which is designed like a ring in the area of the outer diameter e; the outer diameter e of the drilling disk 36 measures approximately 2.5 times the outer diameter i of the pilot drill bit 38. Its free collar length h corresponds to approximately half the drill bit length h 1 .

Die Stirnfläche 40 der Bohrscheibe 36 setzt sich aus einem -- die Bohrkronenachse A rechtwinklig querenden -- kreisförmigen Zentralabschnitt 40z vom Durchmesser n sowie einem schmalen Kegelringabschnitt 40k zusammen, der mit der Bohrkronenachse A einen flachen Konuswinkel w einschließt.The end face 40 of the drilling disk 36 is composed of a circular central section 40 z of diameter n, which crosses the drill bit axis A at right angles, and a narrow conical ring section 40 k , which includes a flat cone angle w with the drill bit axis A.

Der Kegelringabschnitt 40k -- und damit die Stirnfläche 40 -- endet an einer Umfangsfläche 42 der Bohrscheibe 36, die sich in Vortriebsrichtung x erweitert; sie schließt mit der Bohrkronenachse A einen Winkel t von 3° bis 5° ein. Die Stirnfläche 40 der Bohrscheibe 36 ist ebenso wie die Stirnfläche 39 der Vorbohrkrone 38 mit Hartmetallstiften 44 besetzt.The conical ring section 40 k - and thus the end face 40 - ends on a circumferential surface 42 of the drilling disk 36, which widens in the direction of advance x; it includes an angle t of 3 ° to 5 ° with the drill bit axis A. The end face 40 of the drilling disk 36, like the end face 39 of the pilot drill bit 38, is covered with hard metal pins 44.

Von der Stirnfläche 40 gehen in radialem Abstand z zur Umfangsfläche 42 etwa achsparallele Spülkanäle 46 aus, welche die Bohrscheibe 36 durchsetzen; ihr Durchmesser q entspricht etwa einem Sechstel des größten Außendurchmessers e der Bohrkrone 14. Die Spülkanäle 46 münden an der Rücken- oder Unterseite 48 der Bohrscheibe 36. Diese Unterseite 48 ist wie die Stirnfläche 40 gestaltet; an einen inneren Zentralabschnitt 48z schließt ein äußerer Kegelabschnitt 48k an. Die Mittelachse M des Spülkanals 46 verläuft etwa durch einen diese Abschnitte 40k, 40z bzw. 48k, 48z trennenden Konstruktionskreis K.Rinsing channels 46, which are approximately axially parallel and which penetrate the drilling disk 36, emanate from the end face 40 at a radial distance z from the peripheral face 42; their diameter q corresponds to approximately one sixth of the largest outer diameter e of the drill bit 14. The flushing channels 46 open out at the back or underside 48 of the drilling disk 36. This underside 48 is designed like the end face 40; an inner cone section 48 z is adjoined by an outer cone section 48 k . The central axis M of the flushing channel 46 runs approximately through a construction circle K separating these sections 40 k , 40 z or 48 k , 48 z .

In Fig. 2, 4 sind Sackbohrungen 50 der Bohrscheibe 36 an deren Umfangsfläche 42 erkennbar. Diese Sackbohrungen 50 nehmen Hartmetallstifte 44 auf, die der Umfangsfläche 42 als Verschleißschutz dienen. In Fig. 3, 5 wiedergegebene radiale Innennuten 52 im Zentralabschnitt 40z der Stirnfläche 40 verbessern den Bohrgutaustrag.2, 4, blind bores 50 of the drilling disk 36 can be seen on its peripheral surface 42. These blind bores 50 receive hard metal pins 44, which serve the circumferential surface 42 as wear protection. 3, 5 shown radial inner grooves 52 in the central portion 40 z of the end face 40 improve the drilling material discharge.

Der das oben beschriebene Keilwellenprofil 18 anbietende Aufnahmeschaft 16 sitzt in der Bohrkrone 14 der Fig. 2, 3 mittels eines sich in Vortriebsrichtung x verjüngenden Konusringes 54, an den ein nicht dargestelltes Gewinde für die Vorbohrkrone 38 anschließen kann.The receiving shaft 16 which offers the spline profile 18 described above is seated in the drill bit 14 of FIGS. 2, 3 by means of a conical ring 54 tapering in the direction of advance x, to which a thread (not shown) for the pre-drill bit 38 can be connected.

In der Ausgestaltung der Bohrkrone 14a der Fig. 4, 5 ist der Aufnahmeschaft 16 mit einem Bund 56 versehen, der in eine Ringschulter 58 der Bohrscheibe 36a eingreift. Der in Vorschubrichtung x anschließende Lagerabschnitt 16a wird von Paßfedern 60 drehgesichert. Die bohrkopfseitigen Axialnuten dafür sind in Fig. 5 mit 62 bezeichnet.In the embodiment of the drill bit 14 a of Fig. 4, 5 of the shank is provided with a collar 56 16 which engages in an annular shoulder 58 of the Bohrscheibe 36 a. The bearing section 16 a adjoining the feed direction x is secured against rotation by parallel keys 60. The axial grooves for this on the drill head side are designated by 62 in FIG. 5.

Nicht dargestellt ist die Verbindung von Aufnahmeschaft 16 und Bohrscheibe 36 mittels einer Zahnwellen- oder einer Gewindeverbindung.The connection between the mounting shaft 16 and the drilling disk 36 by means of a toothed shaft connection or a threaded connection is not shown.

Zum Herstellen von großen Bohrkronen 14 eines Durchmessers e zwischen 500 mm und 840 mm kann nicht mehr Rundmaterial eingesetzt werden; man muß in diesem Falle Schmiederohlinge verwenden, aus denen man dann in kostengünstiger Weise die Bohrscheibe 36, den Aufnahmeschaft 16 sowie den Vorbohrer 38 einstückig erzeugt.Round material can no longer be used to produce large drill bits 14 with a diameter e between 500 mm and 840 mm; in this case, forging blanks must be used, from which the drilling disk 36, the receiving shaft 16 and the pilot drill 38 are then produced in one piece in a cost-effective manner.

Claims (10)

Bohrkrone für das schlagende Horizontalbohren mittels Imlochhammers mit an einer in Vortriebsrichtung weisenden Stirnfläche angeordnetem Kronenbesatz, insbesondere aus Hartmetallstiften, sowie mit in Abstand zur Bohrkronenachse angeordneten Spüldurchgängen an einer Bohrscheibe der Bohrkrone,
dadurch gekennzeichnet,
daß die Spüldurchgänge von Spülkanälen (46) gebildet sind, die innerhalb der Bohrscheibe (36) in Abstand (z) zu deren Umfangsfläche (42) verlaufen.Drill bit for striking horizontal drilling by means of a down-the-hole hammer with a crown set on an end face pointing in the direction of advance, in particular made of hard metal pins, and with flushing passages on a drill disk of the drill bit arranged at a distance from the drill bit axis,
characterized,
that the flushing passages are formed by flushing channels (46) which run within the drilling disc (36) at a distance (z) from their peripheral surface (42). Bohrkrone mit die Bohrkronenachse querendem Zentralabschnitt der Stirnfläche und nach außen anschließendem, zur Umfangsfläche geneigten Kegelringabschnitt, der in die Umfangsfläche der Bohrscheibe übergeht, nach Anspruch 1, dadurch gekennzeichnet, daß die Spülkanäle (46) am Übergang vom Zentralabschnitt (40z) zum Kegelringabschnitt (40k) der Stirnfläche (40) angeordnet sind.Drill bit with the central section of the end face crossing the drill bit axis and an outwardly adjacent conical ring section inclined to the circumferential surface, which merges into the circumferential surface of the drilling disk, according to claim 1, characterized in that the flushing channels (46) at the transition from the central section (40 z ) to the conical ring section ( 40 k ) of the end face (40) are arranged. Bohrkrone nach Anspruch 1 oder 2, dadurch gekennzeichnet, daß die Spülkanäle (46) am Übergang von einem Zentralabschnitt 48z zu einem anschließenden Kegelringabschnitt (48k) der Rücken- oder Unterfläche (48) der Bohrscheibe (36) angeordnet sind.Drill bit according to claim 1 or 2, characterized in that the rinsing channels (46) are arranged at the transition from a central section 48 z to a subsequent conical ring section (48 k ) of the back or lower surface (48) of the drilling disc (36). Bohrkrone nach Anspruch 2 oder 3, dadurch gekennzeichnet, daß der Kegelringabschnitt (48k) der Rücken- oder Unterseite (48) der Bohrscheibe (36) gegenläufig zu deren Kegelringabschnitt (40k) der Stirnfläche (40) geneigt ist.Drill bit according to claim 2 or 3, characterized in that the tapered ring section (48 k ) of the back or underside (48) of the drilling disc (36) is inclined in the opposite direction to the tapered ring section (40 k ) of the end face (40). Bohrkrone nach einem der Ansprüche 1 bis 4, dadurch gekennzeichnet, daß die Mittelachse (M) des Spülkanals (46) etwa parallel zur Bohrkronenlängsachse (A) verläuft.Drill bit according to one of claims 1 to 4, characterized in that the central axis (M) of the flushing channel (46) runs approximately parallel to the longitudinal axis (A) of the drill bit. Bohrkrone nach einem der Ansprüche 1 bis 5, dadurch gekennzeichnet, daß in der Stirnfläche (40) der Bohrscheibe (36) von der Mündung der Spülkanäle (46) zur Bohrkronenlängsachse (A) radiale Innennuten (52) verlaufen.Drill bit according to one of claims 1 to 5, characterized in that radial inner grooves (52) run in the end face (40) of the drill disc (36) from the mouth of the flushing channels (46) to the drill bit longitudinal axis (A). Bohrkrone mit Aufnahmeschaft für die Bohrscheibe und gegebenenfalls einer bolzenartigen axialen Vorbohrkrone nach wenigstens einem der Ansprüche 1 bis 6, dadurch gekennzeichnet, daß sich der Aufnahmeschaft (16) mit einem Ringbund (56) an der Bohrscheibe (36) abstützt, in der er mit Paßfedern (60) gehalten ist.Drill bit with a holding shaft for the drilling disk and optionally a bolt-like axial pre-drilling bit according to at least one of claims 1 to 6, characterized in that the holding shaft (16) is supported on the drilling disk (36) by an annular collar (56) in which it is fitted with feather keys (60) is held. Bohrkrone mit Aufnahmeschaft für die Bohrscheibe und gegebenenfalls einer bolzenartigen axialen Vorbohrkrone nach wenigstens einem der Ansprüche 1 bis 6, dadurch gekennzeichnet, daß der Aufnahmeschaft (16) in der Bohrscheibe (36) durch eine Zahnwellen- oder Gewindeverbindung gehalten ist.Drill bit with a holding shaft for the drilling disk and, if appropriate, a bolt-like axial pre-drilling bit according to at least one of claims 1 to 6, characterized in that the holding shaft (16) is held in the drilling disk (36) by a splined or threaded connection. Bohrkrone nach wenigstens einem der Ansprüche 1 bis 8, dadurch gekennzeichnet, daß die Bohrscheibe (36) eine von ihr innerhalb der Umfangsfläche (42) gegen die Vortriebsrichtung (x) abragende Manschette (32) trägt, die an der Innenfläche eines in Bohrkronenlängsachse (A) gerichteten Mantelrohres (28) verläuft, wobei gegebenenfalls die Manschette (32) mit der Bohrscheibe (36) verschraubt ist und/oder der Außendurchmesser (d) der Manschette (32) etwa dem Außendurchmesser einer Außenkante (23) einer den Aufnahmeschaft (16) umgebenden Wendel (22) entspricht.Drill bit according to at least one of Claims 1 to 8, characterized in that the drill disc (36) carries a sleeve (32) which projects from it within the circumferential surface (42) against the direction of advance (x) and which is attached to the inner surface of a longitudinal axis (A ) directed casing tube (28), where appropriate the sleeve (32) is screwed to the drilling disc (36) and / or the outer diameter (d) of the sleeve (32) approximately the outer diameter of an outer edge (23) of the receiving shaft (16) surrounding spiral (22) corresponds. Bohrkrone nach einem der Ansprüche 1 bis 9, dadurch gekennzeichnet, daß die Bohrscheibe (36) mit dem Aufnahmeschaft (16) sowie einem axialen Vorbohrer (38) einstückig, insbesondere aus einem Schmiederohling, hergestellt ist.Drill bit according to one of claims 1 to 9, characterized in that the drilling disc (36) with the receiving shaft (16) and an axial pre-drill (38) is made in one piece, in particular from a forging blank.
EP97104925A 1996-04-02 1997-03-22 Drill bit for percussive drilling Withdrawn EP0799966A3 (en)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
DE19613140 1996-04-02
DE19613140 1996-04-02
DE19619194 1996-05-11
DE19619194A DE19619194A1 (en) 1996-04-02 1996-05-11 Drill bit for impact drilling

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Publication Number Publication Date
EP0799966A2 true EP0799966A2 (en) 1997-10-08
EP0799966A3 EP0799966A3 (en) 1999-02-03

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EP97104925A Withdrawn EP0799966A3 (en) 1996-04-02 1997-03-22 Drill bit for percussive drilling

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Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6551295B1 (en) 1998-03-13 2003-04-22 The Procter & Gamble Company Absorbent structures comprising fluid storage members with improved ability to dewater acquisition/distribution members
FR2844312A1 (en) 2002-09-05 2004-03-12 Centre Nat Rech Scient ROTATING MACHINE WITH CAPSULISM
US6713661B1 (en) 1998-04-28 2004-03-30 The Procter & Gamble Company Absorbent articles providing improved fit when wet
US6990403B2 (en) 2002-02-22 2006-01-24 Honda Giken Kogyo Kabushiki Kaisha Control system for plant

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2824958A1 (en) * 1978-06-07 1979-12-13 Willi Wader Fa Monolithic drill rod for tapping blast furnaces - made by hot forging end of thick walled tube to produce drill head possessing six cutters
EP0122103A1 (en) * 1983-04-06 1984-10-17 Hughes Douglas Harrison Machine for boring tunnels
EP0324150A1 (en) * 1988-01-12 1989-07-19 Hawera Probst GmbH + Co. Drilling tool
WO1994024405A1 (en) * 1993-04-08 1994-10-27 Sandvik Ab Down-hole hammer drill having reverse circulation and drill bit for the hammer drill
DE4326000A1 (en) * 1993-08-03 1995-02-09 Srt Rock Tools Handels Und Pro Pin drill bit for percussive drilling

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2824958A1 (en) * 1978-06-07 1979-12-13 Willi Wader Fa Monolithic drill rod for tapping blast furnaces - made by hot forging end of thick walled tube to produce drill head possessing six cutters
EP0122103A1 (en) * 1983-04-06 1984-10-17 Hughes Douglas Harrison Machine for boring tunnels
EP0324150A1 (en) * 1988-01-12 1989-07-19 Hawera Probst GmbH + Co. Drilling tool
WO1994024405A1 (en) * 1993-04-08 1994-10-27 Sandvik Ab Down-hole hammer drill having reverse circulation and drill bit for the hammer drill
DE4326000A1 (en) * 1993-08-03 1995-02-09 Srt Rock Tools Handels Und Pro Pin drill bit for percussive drilling

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6551295B1 (en) 1998-03-13 2003-04-22 The Procter & Gamble Company Absorbent structures comprising fluid storage members with improved ability to dewater acquisition/distribution members
US6713661B1 (en) 1998-04-28 2004-03-30 The Procter & Gamble Company Absorbent articles providing improved fit when wet
US6990403B2 (en) 2002-02-22 2006-01-24 Honda Giken Kogyo Kabushiki Kaisha Control system for plant
FR2844312A1 (en) 2002-09-05 2004-03-12 Centre Nat Rech Scient ROTATING MACHINE WITH CAPSULISM

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