EP0156762A1 - Trepaning cutter - Google Patents

Trepaning cutter Download PDF

Info

Publication number
EP0156762A1
EP0156762A1 EP85810026A EP85810026A EP0156762A1 EP 0156762 A1 EP0156762 A1 EP 0156762A1 EP 85810026 A EP85810026 A EP 85810026A EP 85810026 A EP85810026 A EP 85810026A EP 0156762 A1 EP0156762 A1 EP 0156762A1
Authority
EP
European Patent Office
Prior art keywords
drilling
hollow drill
support segments
segments
end region
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.)
Granted
Application number
EP85810026A
Other languages
German (de)
French (fr)
Other versions
EP0156762B1 (en
Inventor
Karl-Heinz Ing. Gärtner
Franz Hoyss
Heinrich Pauli
Dieter Dipl.-Ing. Scholz
Horst-Detlef Ing. Gassmann
Ernst Wohlwend
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Hilti AG
Original Assignee
Hilti AG
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
Family has litigation
First worldwide family litigation filed litigation Critical https://patents.darts-ip.com/?family=6229642&utm_source=google_patent&utm_medium=platform_link&utm_campaign=public_patent_search&patent=EP0156762(A1) "Global patent litigation dataset” by Darts-ip is licensed under a Creative Commons Attribution 4.0 International License.
Application filed by Hilti AG filed Critical Hilti AG
Priority to AT85810026T priority Critical patent/ATE34329T1/en
Publication of EP0156762A1 publication Critical patent/EP0156762A1/en
Application granted granted Critical
Publication of EP0156762B1 publication Critical patent/EP0156762B1/en
Expired legal-status Critical Current

Links

Images

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B28—WORKING CEMENT, CLAY, OR STONE
    • B28D—WORKING STONE OR STONE-LIKE MATERIALS
    • B28D1/00—Working stone or stone-like materials, e.g. brick, concrete or glass, not provided for elsewhere; Machines, devices, tools therefor
    • B28D1/02—Working stone or stone-like materials, e.g. brick, concrete or glass, not provided for elsewhere; Machines, devices, tools therefor by sawing
    • B28D1/04—Working stone or stone-like materials, e.g. brick, concrete or glass, not provided for elsewhere; Machines, devices, tools therefor by sawing with circular or cylindrical saw-blades or saw-discs
    • B28D1/041—Working stone or stone-like materials, e.g. brick, concrete or glass, not provided for elsewhere; Machines, devices, tools therefor by sawing with circular or cylindrical saw-blades or saw-discs with cylinder saws, e.g. trepanning; saw cylinders, e.g. having their cutting rim equipped with abrasive particles
    • E—FIXED CONSTRUCTIONS
    • E21—EARTH DRILLING; MINING
    • E21B—EARTH DRILLING, e.g. DEEP DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
    • E21B10/00—Drill bits
    • E21B10/46—Drill bits characterised by wear resisting parts, e.g. diamond inserts
    • E21B10/48—Drill bits characterised by wear resisting parts, e.g. diamond inserts the bit being of core type

Definitions

  • the invention relates to a hollow drill with a metallic, hollow cylindrical carrier body which has an open end on the drilling direction side with supporting segments for cutting teeth made of diamond grain arranged at a distance from one another in the circumferential direction.
  • Hollow drills are known for producing bores in rock, concrete and the like materials, which have a cylindrical support body with supporting segments for cutting teeth made of diamond grain.
  • the support segments of these known hollow drills consist of a matrix in which the diamond grains are embedded.
  • the free end face of these support segments is each designed as a plane plane running normal to the longitudinal axis of the hollow drill.
  • the supporting segments are produced by sintering, which means that there are no free-standing diamond grains on the surface.
  • the support segments produced in this way are therefore due to the lack of free-standing diamond grains neither suitable for the tapping process nor for the actual drilling process.
  • the invention has for its object to provide a hollow drill of the type mentioned, the support segments are economically producible and also ensure a perfect drilling process, which is particularly feasible without separate aids, such as additional holding by the operator.
  • the object is achieved in that the end region of the support segments on the drilling direction tapers at least over part of their length in the drilling direction and the free end face forms a line running in the circumferential direction along at least part of the tapered end region of the support segments.
  • the support segments with a tapered end area according to the invention are also preferably produced by sintering, this production also having the result that no diamond grains acting as cutting teeth are exposed on the surface.
  • the tapered end area of new support segments manufactured in this way comes into contact with the drilling material during the first tapping process, a part of the matrix is removed very quickly due to the extraordinarily high specific stress in the area of the free linear end face, so that a small number of diamond grains are removed in that area be exposed. Since these exposed diamond grains lie essentially on a line extending in the circumferential direction, they create a guideway immediately after hitting the drilling material. This guideway prevents the hollow drill bit from moving to the side and increases continuously as the drilling process continues.
  • the entire surface of the supporting segments gradually comes into contact with the drill material, so that diamond grains are continuously exposed in those areas by removing the matrix.
  • the large number of exposed diamond grains can no longer lead to lateral evasion of the hollow drill thanks to the already existing sufficient guidance.
  • the tapered region of the support segments has fulfilled its task if a sufficient guideway for the hollow drill, which prevents lateral deflection, is created.
  • the design of the support segments is therefore advantageously carried out in such a way that the tapered area is degraded when the remaining surface of the support segments has reached a condition suitable for the further drilling process. With such drilled support segments you can then without partial appearances, both tapping and actual drilling operations are carried out.
  • the tapering end region of the support segments advantageously has one or more radially inclined side surfaces.
  • the side surfaces inclined in this way can extend over the entire length or only over part of the length of the support segments. It is also possible to combine these radially inclined side surfaces with one or more boundary surfaces inclined in the circumferential direction.
  • Such side surfaces inclined in the circumferential direction which lead to a shortening of the line running in the circumferential direction, can be arranged upstream, downstream or also arranged on both sides in the direction of rotation of the hollow drill.
  • the speed of removal of the tapered end area can be influenced both by the dimensioning in terms of size and by the formal design.
  • the tapered end region of the support segments preferably has radially rectilinear side surfaces.
  • the tapering end region is preferably formed by an inclined side surface.
  • the side surface which is expediently inclined at an angle of 50 ° -80 °, preferably 70 °, to the drill axis can either extend towards the peripheral edge of the support segment in the drilling direction or decrease in the drilling direction.
  • the end region of the support segments on the drilling direction side is formed by two inclined side surfaces.
  • This embodiment ensures a favorable load due to the symmetrical design, since the krj te attack centrally. This occurs especially with side surfaces that are preferably inclined at the same angle.
  • Such tra segments lead to advantages in terms of strength and additionally result in a favorable load on, for example made by a soldering process connection to the hollow cylindrical support body of the hollow drill.
  • the angle enclosed between the two side surfaces can be between 60 ° and 120 ° and preferably 90 °. This inclination of the side surfaces on the one hand fulfills the strength requirements for the support segments and on the other hand ensures that a sufficient number of diamond grains is uncovered quickly enough for drilling during the first contact between the support segments and the drilling material.
  • the improvement in the drilling behavior is achieved by the end face of the hollow drill, which is at least partially designed as a line.
  • the invention relates in particular to the further development of these supporting segments.
  • a taper of such supports can also be formed by one or more radially inclined side surfaces, wherein such side surfaces preferably also run in a straight line and can have the aforementioned angular mass.
  • FIG. 1 shows a hollow drill designated 1 overall. This consists of a hollow cylindrical carrier body 2 with a drive shaft 3 protruding counter to the drilling direction. Cutting teeth 6 formed by diamond grain are embedded in these.
  • the end region of the support segments 5 on the drilling direction side is tapered in the drilling direction, with two side surfaces 7 running at an angle symmetry relative to one another forming an angle ⁇ of 90 °.
  • the intersection of the side surfaces 7 forms a line 8 running in the circumferential direction, along which incisors 6 are exposed during the drilling process.
  • the support segments 5 are form-fitting on the support body 2 and fixed, for example, by soldering.
  • the cutting teeth 6 or 14 lying on the line 8 or 13 first create a guide groove which prevents the hollow drill 1 from evading radially from the start.
  • Two radially inclined side surfaces 22 form a circumferential line 23 along their intersection.
  • the tapered end region of the support segments 21 also has a circumferentially inclined boundary surface 24 on, which can be upstream or downstream of the direction of rotation of the hollow drill.
  • Cutting teeth 25 in the form of diamond grain are also embedded in the supporting segment 21.
  • FIG. 6 shows a support segment, designated overall by 31, which is arranged on a support body 2 and has two radially inclined side surfaces 32.
  • the radius r of the line 33 formed by the intersection of the side surfaces falls below the average radius R of the carrier body 2, the support segment 31 being arranged in such a way that the maximum dimension of the radius difference is at the segment ends.
  • boundary surfaces 34 are provided in order to avoid the radius difference which has a disadvantageous effect on the creation of a guide groove. These boundary surfaces 34 lead to a shortening of the line 33. The radius difference has thus been reduced in such a way that it can no longer have a disadvantageous effect when the guide groove is created.

Abstract

1. A hollow drill bit comprising a metallic hollow cylindrical supporting body (2) having an open end in the direction of drilling with positively secured equally shaped support segments (5, 11, 21, 31) spaced apart from each other around the circumference in which cutting teeth of diamond grain are embeded where the support segments protrude beyond the end face of the supporting body (2) in the direction of drilling, characterized in that the end section of the supporting segments (5, 11, 21, 31) at the drilling end tapers over at least a part of its length in the direction of drilling and the free end face forms a line (8, 13, 23, 33) running in the direction of the circumference over at least a part of the tapered end section of the support segments.

Description

Die Erfindung betrifft einen Hohlbohrer mit einem metallischen, hohlzylindrischen Trägerkörper, der ein bohrrichtungsseitig offenes Ende mit in Umfangsrichtung im Abstand voneinander angeordneten Tragsegmenten für Schneidzähne aus Diamantkorn aufweist.The invention relates to a hollow drill with a metallic, hollow cylindrical carrier body which has an open end on the drilling direction side with supporting segments for cutting teeth made of diamond grain arranged at a distance from one another in the circumferential direction.

Zum Herstellen von Bohrungen in Gestein, Beton und dergleichen Materialien sind Hohlbohrer bekannt, die einen zylindrischen Trägerkörper mit Tragsegmenten für Schneidzähne aus Diamantkorn aufweisen. Die Tragsegmente dieser bekannten Hohlbohrer bestehen aus einer Matrix, in welcher die Diamantkörner eingebettet sind. Die freie Stirnseite dieser Tragsegmente ist jeweils als plane, normal zur Längsachse des Hohlbohrers verlaufende Ebene ausgebildet.Hollow drills are known for producing bores in rock, concrete and the like materials, which have a cylindrical support body with supporting segments for cutting teeth made of diamond grain. The support segments of these known hollow drills consist of a matrix in which the diamond grains are embedded. The free end face of these support segments is each designed as a plane plane running normal to the longitudinal axis of the hollow drill.

In der Regel werden die Tragsegmente durch Sintern hergestellt, was dazu führt, dass an der Oberfläche keine freistehenden Diamantkörner vorhanden sind. Die derart hergestellten Tragsegmente sind damit aufgrund der fehlenden freistehenden Diamantkörner weder für den Anbohrvorgang noch für den eigentlichen Bohrvörgang geeignet.As a rule, the supporting segments are produced by sintering, which means that there are no free-standing diamond grains on the surface. The support segments produced in this way are therefore due to the lack of free-standing diamond grains neither suitable for the tapping process nor for the actual drilling process.

Um zu Tragsegmenten zu kommen, die sich dank der an der Oberfläche freistehenden Diamantkörner für den Anbohr- und Bohrvorgang eignen, ist es notwendig, die Matrix teilweise zu entfernen. Dies kann durch hinreichend bekannte materialabtragende Verfahren erreicht werden.In order to obtain support segments that are suitable for drilling and drilling thanks to the free-standing diamond grains on the surface, it is necessary to partially remove the matrix. This can be achieved by well-known material-removing processes.

Es hat sich gezeigt, dass durch diese bekannten materialabtragenden Verfahren relativ viele Diamantkörner an den Tragsegmenten freigelegt werden, so insbesondere auch an deren bohrrichtungsseitigen Stirnseite. Dadurch ist einerseits die Durchführung des eigentlichen Bohrvorganges möglich, während andererseits der Anbohrvorgang ganz erheblich erschwert ist. Insbesondere ist der Anbohrvorgang von einem dauernden, seitlichen Ausweichen des Hohlbohrers beim Aufsetzen auf das Bohrgut geprägt, was zu Erschütterungen und Schwingungen mit einer damit verbundenen übermässigen Beanspruchung der Bohrgeräte führt.It has been shown that by means of these known material-removing processes, a relatively large number of diamond grains are exposed on the support segments, in particular also on their end face on the drilling direction side. This makes it possible to carry out the actual drilling process on the one hand, while on the other hand the drilling process is made considerably more difficult. In particular, the tapping process is characterized by a constant lateral deflection of the hollow drill when it is placed on the drill material, which leads to shocks and vibrations with an associated excessive stress on the drilling equipment.

Nachdem obige Nachteile nur bei Hohlbohrern mit neuen Tragsegmenten auftreten und Hohlbohrer, die eine längere Einbohrphase hinter sich haben, bereits befriedigende Resultate hinsichtlich des Anbohrvorganges bringen, wurde versucht, das materialabtragende Verfahren an neuen Tragsegmenten in stark abrasivem Untergrund durchzuführen. Einerseits kann mit diesem Verfahren nur eine geringfügige Verbesserung erzielt werden, während andererseits von wesentlicher Bedeutung ist, dass durch den zusätzlichen Aufwand weitere Nachteile, insbesondere in wirtschaftlicher Hinsicht, geschaffen werden.Since the above disadvantages only occur with hollow drills with new support segments and hollow drills that have a long drilling phase behind them already produce satisfactory results with regard to the drilling process, an attempt was made to carry out the material-removing process on new support segments in a strongly abrasive surface. On the one hand, only a slight improvement can be achieved with this method, while on the other hand it is essential that the additional effort creates additional disadvantages, particularly in economic terms.

Der Erfindung liegt die Aufgabe zugrunde, einen Hohlbohrer der eingangs genannten Art zu schaffen, dessen Tragsegmente wirtschaftlich herstellbar sind und ausserdem einen einwandfreien Anbohrvorgang gewährleisten, der insbesondere ohne gesonderte Hilfsmittel, wie beispielsweise zusätzliches Halten durch die Bedienungsperson, durchführbar ist.The invention has for its object to provide a hollow drill of the type mentioned, the support segments are economically producible and also ensure a perfect drilling process, which is particularly feasible without separate aids, such as additional holding by the operator.

Erfindungsgemäss wird die Aufgabe dadurch gelöst, dass der bohrrichtungsseitige Endbereich der Tragsegmente sich wenigstens über einen Teil ihrer Länge in Bohrrichtung verjüngt und die freie Stirnseite entlang wenigstens eines Teils des verjüngten Endbereiches der Tragsegmente eine in Umfangsrichtung verlaufende Linie bildet.According to the invention, the object is achieved in that the end region of the support segments on the drilling direction tapers at least over part of their length in the drilling direction and the free end face forms a line running in the circumferential direction along at least part of the tapered end region of the support segments.

Auch die Tragsegmente mit einem erfindungsgemäss verjüngten Endbereich werden vorzugsweise durch Sintern hergestellt, wobei auch diese Herstellung zur Folge hat, dass an der Oberfläche noch keine als Schneidzähne wirkende Diamantkörner freiliegen. Kommt nun aber der verjüngte Endbereich neuer derartig hergestellter Tragsegmente beim ersten Anbohrvorgang mit dem Bohrgut in Kontakt, wird aufgrund der ausserordentlich hohen spezifischen Beanspruchung im Bereich der freien linienförmigen Stirnseite ein Teil der Matrix sehr schnell abgetragen, so dass in jenem Bereich eine geringe Zahl von Diamantkörnern freigelegt werden. Da diese freigelegten Diamantkörner im wesentlichen auf einer sich in Umfangsrichtung erstreckenden Linie liegen, schaffen sie unmittelbar nach dem Auftreffen auf das Bohrgut eine Führungsbahn. Diese Führungsbahn verhindert ein seitliches Ausweichen des Hohlbohrers und vergrössert sich bei Weiterführung des Anbohrvorganges laufend. Beim Uebergang des Anbohrvorganges in den eigentlichen Bohrvorgang kommt allmählich die gesamte Oberfläche der Tragsegmente mit dem Bohrgut in Kontakt, so dass auch in jenen Bereichen durch Abtragen der Matrix laufend Diamantkörner freigelegt werden. Die Vielzahl von freigelegten Diamantkörnern kann dank der bereits bestehenden ausreichenden Führung nicht mehr zu einem seitlichen Ausweichen des Hohlbohrers führen.The support segments with a tapered end area according to the invention are also preferably produced by sintering, this production also having the result that no diamond grains acting as cutting teeth are exposed on the surface. However, if the tapered end area of new support segments manufactured in this way comes into contact with the drilling material during the first tapping process, a part of the matrix is removed very quickly due to the extraordinarily high specific stress in the area of the free linear end face, so that a small number of diamond grains are removed in that area be exposed. Since these exposed diamond grains lie essentially on a line extending in the circumferential direction, they create a guideway immediately after hitting the drilling material. This guideway prevents the hollow drill bit from moving to the side and increases continuously as the drilling process continues. During the transition from the drilling process to the actual drilling process, the entire surface of the supporting segments gradually comes into contact with the drill material, so that diamond grains are continuously exposed in those areas by removing the matrix. The large number of exposed diamond grains can no longer lead to lateral evasion of the hollow drill thanks to the already existing sufficient guidance.

Wie die obigen Ausführungen zeigen, hat der verjüngte Bereich der Tragsegmente seine Aufgabe erfüllt, wenn eine das seitliche Ausweichen verhindernde, ausreichende Führungsbahn für den Hohlbohrer geschaffen ist. Die Gestaltung der Tragsegmente erfolgt demnach mit Vorteil derart, dass der verjüngte Bereich dann abgebaut ist, wenn die restliche Oberfläche der Tragsegmente eine für den weiteren Bohrvorgang geeignete Beschaffenheit erreicht hat. Mit solch eingebohrten Tragsegmenten können dann ohne nachteilige Erscheinungen sowohl Anbohr- als auch eigentliche Bohrvorgänge durchgeführt werden.As the above explanations show, the tapered region of the support segments has fulfilled its task if a sufficient guideway for the hollow drill, which prevents lateral deflection, is created. The design of the support segments is therefore advantageously carried out in such a way that the tapered area is degraded when the remaining surface of the support segments has reached a condition suitable for the further drilling process. With such drilled support segments you can then without partial appearances, both tapping and actual drilling operations are carried out.

Der sich verjüngende Endbereich der Tragsegmente weist mit Vorteil eine oder mehrere radial geneigte Seitenflächen auf. Die derart geneigten Seitenflächen können sich sowohl über die gesamte als auch nur über einen Teil der Länge der Tragsegmente erstrecken. Ausserdem besteht die Möglichkeit, diese radial geneigten Seitenflächen mit einer oder mehreren in Umfangsrichtung geneigten Begrenzungsflächen zu kombinieren. Solche in Umfangsrichtung geneigte Seitenflächen, welche zu einer Verkürzung der in Umfangsrichtung verlaufenden Linie führen, können in Drehrichtung des Hohlbohrers vorgeschaltet, nachgeschaltet oder auch beidseitig angeordnet sein.The tapering end region of the support segments advantageously has one or more radially inclined side surfaces. The side surfaces inclined in this way can extend over the entire length or only over part of the length of the support segments. It is also possible to combine these radially inclined side surfaces with one or more boundary surfaces inclined in the circumferential direction. Such side surfaces inclined in the circumferential direction, which lead to a shortening of the line running in the circumferential direction, can be arranged upstream, downstream or also arranged on both sides in the direction of rotation of the hollow drill.

Die Geschwindigkeit des Abtragens des sich verjüngenden Endbereiches kann sowohl durch die grössenmässige Dimensionierung als auch durch die formliche Gestaltung beeinflusst werden. Hinsicht lich der Gestaltung weist der sich verjüngende Endbereich der Tragsegmente vorzugsweise radial geradlinig verlaufende Seitenflächen auf.The speed of removal of the tapered end area can be influenced both by the dimensioning in terms of size and by the formal design. Regarding the design, the tapered end region of the support segments preferably has radially rectilinear side surfaces.

Bezüglich der Herstellung der Tragsegmente ergeben sich Vorteile, wenn vorzugsweise der sich verjüngende Endbereich von einer geneigten Seitenfläche gebildet ist. Die zweckmässigerweise unter einem Winkel von 50° - 80°, vorzugsweise 70°, zur Bohrerachse geneigte Seitenfläche kann entweder zum Umfangsrand des Tragsegmentes hin in Bohrrichtung steigend oder in Bohrrichtung fallend verlaufen.With regard to the production of the support segments, there are advantages if the tapering end region is preferably formed by an inclined side surface. The side surface, which is expediently inclined at an angle of 50 ° -80 °, preferably 70 °, to the drill axis can either extend towards the peripheral edge of the support segment in the drilling direction or decrease in the drilling direction.

Nach einem weiteren Vorschlag der Erfindung ist der bohrrichtungsseitige Endbereich der Tragsegmente von zwei geneigten Seitenflächen gebildet. Diese Ausführungsform gewährleistet durch die symmetrische Ausbildung eine günstige Belastung, da die Kräj te mittig angreifen. Dies tritt vor allem bei Seitenflächen auf die vorzugsweise unter gleichem Winkel geneigt sind. Solche Tra< segmente führen zu Vorteilen in festigkeitsmässiger Hinsicht un< ergeben zusätzlich eine günstige Belastung der beispielsweise durch einen Lötvorgang hergestellten Verbindung mit dem hohlzylindrischen Trägerkörper des Hohlbohrers.According to a further proposal of the invention, the end region of the support segments on the drilling direction side is formed by two inclined side surfaces. This embodiment ensures a favorable load due to the symmetrical design, since the krj te attack centrally. This occurs especially with side surfaces that are preferably inclined at the same angle. Such tra segments lead to advantages in terms of strength and additionally result in a favorable load on, for example made by a soldering process connection to the hollow cylindrical support body of the hollow drill.

Der zwischen den beiden Seitenflächen eingeschlossene Winkel kann zwischen 60° und 120° liegen und vorzugsweise 90° betragen. Diese Neigung der Seitenflächen erfüllt einerseits die festigkeitsmässigen Anforderungen an die Tragsegmente und stellt andererseits sicher, dass für das Anbohren im Rahmen des ersten Kontaktes zwischen Tragsegmenten und Bohrgut eine genügende Anzahl an Diamantkörnern schnell genug freigelegt wird.The angle enclosed between the two side surfaces can be between 60 ° and 120 ° and preferably 90 °. This inclination of the side surfaces on the one hand fulfills the strength requirements for the support segments and on the other hand ensures that a sufficient number of diamond grains is uncovered quickly enough for drilling during the first contact between the support segments and the drilling material.

Wie die Erfindung zeigt, kommt die Verbesserung des Anbohrverhaltens durch die wenigstens teilweise als Linie ausgebildete Stirnseite des Hohlbohrers zustande. Nachdem bei Hohlbohrern mit grösserem Durchmesser hauptsächlich Tragsegmente der geschilderten Art verbreitet sind, bezieht sich die Erfindung insbesondere auf die Weiterbildung dieser Tragsegmente. Dies soll jedoch nicht ausschliessen, dass beispielsweise bei Hohlbohrern von kleinerem Durchmesser auch ringförmige, den Umfang des Trägerkörpers vollumfänglich umgebende Träger, bestehend aus einer Matrix und eingebetteten Diamantkörnern, in erfindungsgemässer Weise sich in Bohrrichtung verjüngen können. Auch eine Verjüngung solcher Träger kann durch eine oder mehrere radial geneigte Seitenflächen ausgebildet sein, wobei vorzugsweise auch solche Seitenflächen geradlinig verlaufen und die vorstehend erwähnten Winkelmasse aufweisen können.As the invention shows, the improvement in the drilling behavior is achieved by the end face of the hollow drill, which is at least partially designed as a line. Since mainly supporting segments of the type described are widespread in hollow drills with a larger diameter, the invention relates in particular to the further development of these supporting segments. However, this should not rule out the fact that, for example in the case of hollow drills of smaller diameter, ring-shaped supports, which completely surround the circumference of the support body and consist of a matrix and embedded diamond grains, can taper in the drilling direction in the manner according to the invention. A taper of such supports can also be formed by one or more radially inclined side surfaces, wherein such side surfaces preferably also run in a straight line and can have the aforementioned angular mass.

Die Erfindung wird nachstehend an Hand einer Zeichnung, die Ausführungsbeispiele wiedergibt, näher erläutert. Es zeigen:

  • Fig 1 einen Hohlbohrer in perspektivischer Darstellung;
  • Fig 2 einen Detail-Schnitt durch ein Tragsegment des Hohlbohrers nach Fig 1, in vergrösserter Darstellung;
  • Fig 3 einen Detail-Schnitt durch eine weitere Ausführungsform eines Tragsegmentes;
  • Fig 4 eine Ansicht auf eine weitere Ausführungsform eines Tragsegmentes;
  • Fig 5 einen Grundriss des Tragsegmentes nach Fig 4;
  • -Fig 6 einen Grundriss von einer weiteren Ausführungsform eines Tragsegmentes.
The invention is explained below with reference to a drawing that shows exemplary embodiments. Show it:
  • 1 shows a hollow drill in a perspective view;
  • 2 shows a detail section through a support segment of the hollow drill according to FIG. 1, on an enlarged scale;
  • 3 shows a detail section through a further embodiment of a support segment;
  • 4 shows a view of a further embodiment of a support segment;
  • 5 shows a plan view of the support segment according to FIG. 4;
  • 6 shows a plan view of a further embodiment of a support segment.

Die Fig. 1 zeigt einen insgesamt mit 1 bezeichneten Hohlbohrer. Dieser besteht aus einem hohlzylindrischen Trägerkörper 2 mit entgegen der Bohrrichtung von diesem abragendem Antriebsschaft 3. Auf dem in Bohrrichtung offenen Ende 4 des Trägerkörpers 2 sitzen beispielhaft vier insgesamt mit 5 bezeichnete Tragsegmente. In diese sind durch Diamantkorn gebildete Schneidzähne 6 eingebettet.1 shows a hollow drill designated 1 overall. This consists of a hollow cylindrical carrier body 2 with a drive shaft 3 protruding counter to the drilling direction. Cutting teeth 6 formed by diamond grain are embedded in these.

Wie die Fig. 2 verdeutlicht, ist der bohrrichtungsseitige Endbereich der Tragsegmente 5 in Bohrrichtung verjüngt ausgebildet, wobei zwei zueinander winkelsymmetrisch verlaufende Seitenflächen 7 einen Winkel α von 90° einschliessen. Die Schnittstelle der Seitenflächen 7 bildet eine in Umfangsrichtung verlaufende Linie 8, entlang derer beim Anbohrvorgang Schneidezähne 6 freigelegt werden.As illustrated in FIG. 2, the end region of the support segments 5 on the drilling direction side is tapered in the drilling direction, with two side surfaces 7 running at an angle symmetry relative to one another forming an angle α of 90 °. The intersection of the side surfaces 7 forms a line 8 running in the circumferential direction, along which incisors 6 are exposed during the drilling process.

Die Tragsegmente 5 sind auf dem Trägerkörper 2 formschlüssig und beispielsweise durch Verlötung festgelegt.The support segments 5 are form-fitting on the support body 2 and fixed, for example, by soldering.

Auch insgesamt mit 11 bezeichnete Tragsegmente gemäss Fig 3 sitzen in gleicher Weise auf einem Trägerkörper 2. Der bohrrichtungsseitige Endbereich ist durch eine geneigt verlaufende Seitenfläche 12 in Bohrrichtung verjüngt, wobei die Seitenfläche unter einem Winkel/3 von ca 70° zur Bohrerachse geneigt ist. Dadurch entsteht wiederum eine in Umfangsrichtung verlaufende Linie 13. In den Tragsegmenten 11 sind ebenso Schneidzähne 14 in Form von Diamantkorn eingelagert, so dass einige beim Anbohrvorgang entlang der Linie 13 freigelegt werden.3 in the same way sit on a carrier body 2. The end region on the drilling direction side is tapered in the drilling direction by an inclined side surface 12, the side surface being inclined at an angle / 3 of approximately 70 ° to the drill axis. This in turn creates a line 13 running in the circumferential direction. In the supporting segments 11 there are also cutting teeth 14 in Form of diamond grain stored so that some are exposed during the tapping process along line 13.

Beim Anbohrvorgang schaffen zuerst die auf der Linie 8 bzw 13 liegenden Schneidzähne 6 bzw 14 eine Führungsnut, die ein radiales Ausweichen des Hohlbohrers 1 von Anbeginn an unterbindet.During the tapping process, the cutting teeth 6 or 14 lying on the line 8 or 13 first create a guide groove which prevents the hollow drill 1 from evading radially from the start.

Das insgesamt mit 21 bezeichnete Tragsegment nach den Fig. 4 und 5 sitzt wiederum auf einem Trägerkörper 2. Zwei radial geneigte Seitenflächen 22 bilden entlang deren Schnittstelle eine in Umfangsrichtung verlaufende Linie 23. Der verjüngte Endbereich der Tragsegmente 21 weist ferner eine in Umfangsrichtung geneigte Begrenzungsfläche 24 auf, die der Drehrichtung des Hohlbohrers vor- oder nachgeschaltet sein kann. Im Tragsegment 21 sind ebenso Schneidzähne 25 in Form von Diamantkorn eingebettet.4 and 5 in turn sits on a carrier body 2. Two radially inclined side surfaces 22 form a circumferential line 23 along their intersection. The tapered end region of the support segments 21 also has a circumferentially inclined boundary surface 24 on, which can be upstream or downstream of the direction of rotation of the hollow drill. Cutting teeth 25 in the form of diamond grain are also embedded in the supporting segment 21.

Aus wirtschaftlichen Gründen kommt es in der Praxis oft vor, dass Trägerkörper unterschiedlichen Durchmessers innerhalb gewisser Grenzen mit einheitlichen Tragsegmenten versehen werden. Aufgrund dieser Massnahme können Unterschiede zwischen dem Krümmungsradius und dem Radius des Trägerkörpers entstehen, wobei das Höchstmass dieser Radiusdifferenz je nach Anordnung in der Mitte oder an den Enden der Tragsegmente vorhanden sein kann.For economic reasons, it often happens in practice that support bodies of different diameters are provided with uniform support segments within certain limits. Due to this measure, differences can arise between the radius of curvature and the radius of the support body, the maximum dimension of this radius difference being present, depending on the arrangement, in the middle or at the ends of the support segments.

Die Fig. 6 zeigt ein insgesamt mit 31 bezeichnetes Tragsegment, das auf einem Trägerkörper 2 angeordnet ist und zwei radial geneigte Seitenflächen 32 aufweist. Wie in der Figur beispielhaft dargestellt, unterschreitet der Radius r der durch die Schnittstelle der Seitenflächen gebildeten Linie 33 den mittleren Radius R des Trägerkörpers 2, wobei das Tragsegment 31 derart angeordnet ist, dass sich das Höchstmass der Radiusdifferenz an den Segmentenden befindet. Zur Vermeidung der sich auf die Schaffung einer Führungsnut nachteilig auswirkenden Radiusdifferenz sind Begrenzungsflächen 34 vorgesehen. Diese Begrenzungsflächen 34 führen zu einer Verkürzung der Linie 33. Die Radiusdifferenz ist damit derart verkleinert worden, dass sie sich bei der Schaffung der Führungsnut nicht mehr nachteilig auswirken kann.FIG. 6 shows a support segment, designated overall by 31, which is arranged on a support body 2 and has two radially inclined side surfaces 32. As shown by way of example in the figure, the radius r of the line 33 formed by the intersection of the side surfaces falls below the average radius R of the carrier body 2, the support segment 31 being arranged in such a way that the maximum dimension of the radius difference is at the segment ends. In order to avoid the radius difference which has a disadvantageous effect on the creation of a guide groove, boundary surfaces 34 are provided. These boundary surfaces 34 lead to a shortening of the line 33. The radius difference has thus been reduced in such a way that it can no longer have a disadvantageous effect when the guide groove is created.

Claims (9)

1. Hohlbohrer mit einem metallischen, hohlzylindrischen Trägerkörper, der ein bohrrichtungsseitig offenes Ende mit in Umfangsrichtung im Abstand voneinander angeordneten Tragsegmenten für Schneidzähne aus Diamantkorn aufweist, dadurch gekennzeichnet , dass der bohrrichtungsseitige Endbereich der Tragsegmente (5, 11, 21, 31) sich wenigstens über einen Teil ihrer Länge in Bohrrichtung verjüngt und die freie Stirnseite entlang wenigstens eines Teils des verjüngten Endbereiches der Tragsegmente eine in Umfangsrichtung verlaufende Linie (8, 13, 23 33) bildet.1. Hollow drill with a metallic, hollow cylindrical carrier body which has an open end on the drilling direction side with supporting segments for cutting teeth made of diamond grain arranged at a distance from one another in the circumferential direction, characterized in that the end region of the supporting segments (5, 11, 21, 31) on the drilling direction side overlaps at least part of its length tapers in the direction of drilling and the free end face forms a circumferential line (8, 13, 23 33) along at least part of the tapered end region of the support segments. 2. Hohlbohrer nach Anspruch 1 dadurch gekennzeichnet, dass de. sich in Bohrrichtung verjüngende Endbereich der Tragsegmen te (5, 11, 21, 31) eine oder mehrere radial geneigte Seitenflächen (7, 12, 22, 32) aufweist.2. Hollow drill according to claim 1, characterized in that de. End region of the support segments (5, 11, 21, 31) tapering in the drilling direction has one or more radially inclined side surfaces (7, 12, 22, 32). 3. Hohlbohrer nach Anspruch 2, dadurch gekennzeichnet, dass die Seitenflächen (7, 12, 22, 32) geradlinig verlaufen.3. Hollow drill according to claim 2, characterized in that the side surfaces (7, 12, 22, 32) run in a straight line. 4. Hohlbohrer nach einem der Ansprüche 1 bis 3, dadurch gekennzeichnet, dass der sich in Bohrrichtung verjüngende Endbereich der Tragsegmente (21, 31) eine oder mehrere in Umfangsrichtung geneigte Begrenzungsflächen (24, 34) aufweist.4. Hollow drill according to one of claims 1 to 3, characterized in that the tapering in the drilling direction end region of the support segments (21, 31) has one or more circumferential inclined boundary surfaces (24, 34). 5. Hohlbohrer nach einem der Ansprüche 1 bis 4 dadurch gekennzeichnet, dass der sich verjüngende Endbereich der Tragsegmente (11) von einer geneigten Seitenfläche (12) gebildet ist.5. Hollow drill according to one of claims 1 to 4, characterized in that the tapering end region of the support segments (11) is formed by an inclined side surface (12). 6. Hohlbohrer nach Anspruch 5 dadurch gekennzeichnet, dass die Seitenfläche (12) unter einem Winkel (ß) von 50° bis 80° zur Bohrerachse geneigt ist.6. Hollow drill according to claim 5, characterized in that the side surface (12) is inclined at an angle (β) of 50 ° to 80 ° to the drill axis. 7. Hohlbohrer nach einem der Ansprüche 1 bis 4 dadurch gekennzeichnet, dass der bohrrichtungsseitige Endbereich der Tragsegmente (5, 21, 31) von zwei geneigten Seitenflächen (7, 22, 32) gebildet ist.7. Hollow drill according to one of claims 1 to 4, characterized in that the end region of the support segments (5, 21, 31) on the drilling direction side is formed by two inclined side surfaces (7, 22, 32). 8. Hohlbohrer nach Anspruch 7 dadurch gekennzeichnet, dass die beiden Seitenflächen (7, 22, 32) unter gleichem Winkel geneigt sind.8. Hollow drill according to claim 7, characterized in that the two side surfaces (7, 22, 32) are inclined at the same angle. 9. Hohlbohrer nach Anspruch 7 oder 8 dadurch gekennzeichnet, dass der zwischen den beiden Seitenflächen (7, 22, 32) eingeschlossene Winkel (w-) 60° bis 120° beträgt.9. Hollow drill according to claim 7 or 8, characterized in that the angle (w) between the two side surfaces (7, 22, 32) is 60 ° to 120 °.
EP85810026A 1984-03-05 1985-01-25 Trepaning cutter Expired EP0156762B1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT85810026T ATE34329T1 (en) 1984-03-05 1985-01-25 HOLLOW DRILL.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE3408092 1984-03-05
DE19843408092 DE3408092A1 (en) 1984-03-05 1984-03-05 HOLLOW DRILL

Publications (2)

Publication Number Publication Date
EP0156762A1 true EP0156762A1 (en) 1985-10-02
EP0156762B1 EP0156762B1 (en) 1988-05-18

Family

ID=6229642

Family Applications (1)

Application Number Title Priority Date Filing Date
EP85810026A Expired EP0156762B1 (en) 1984-03-05 1985-01-25 Trepaning cutter

Country Status (3)

Country Link
EP (1) EP0156762B1 (en)
AT (1) ATE34329T1 (en)
DE (2) DE3408092A1 (en)

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0221548A2 (en) * 1985-11-05 1987-05-13 Disco Abrasive Systems, Ltd. Cutting tool having concentrically arranged outside and inside abrasive grain layers and method for production thereof
DE8715431U1 (en) * 1986-12-10 1988-04-07 Fa. Herbert Happe, 5600 Wuppertal, De
EP0583629A1 (en) * 1992-08-10 1994-02-23 Bauer Spezialtiefbau GmbH Core bit comprising removable toothed elements with a peripheral distribution
EP0857552A2 (en) * 1997-01-27 1998-08-12 Tyrolit Schleifmittelwerke Swarovski KG Stone cutting element with increased wear resistance
EP0985505A2 (en) * 1998-09-10 2000-03-15 Atock Co., Ltd. Outer-Diameter blade, inner-diameter blade, core drill and processing machines using same ones
GB2423540A (en) * 2005-02-24 2006-08-30 Marcrist Internat Ltd Core drills and cutting discs
GB2423536A (en) * 2005-02-24 2006-08-30 Marcrist Internat Ltd Diamond core drill
GB2423538A (en) * 2005-02-24 2006-08-30 Marcrist Internat Ltd Core drilling segments with side protection
RU168413U1 (en) * 2016-05-18 2017-02-02 Акционерная Компания "АЛРОСА" (публичное акционерное общество) (АК "АЛРОСА" (ПАО)) DRILL BIT

Families Citing this family (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3533929A1 (en) * 1985-05-07 1986-11-13 Geißler & Kuper GmbH Diamantwerkzeug - Wiederaufbereitung, 3100 Celle Diamond bit with shank tube and threaded tube connection
DE3603499A1 (en) * 1985-05-07 1986-11-13 Geißler & Kuper GmbH Diamantwerkzeug - Wiederaufbereitung, 3100 Celle Diamond bit with shank tube and threaded tube connection
DE3706641A1 (en) * 1987-03-02 1988-09-15 Hilti Ag HOLLOW DRILL
DE8805449U1 (en) * 1988-04-25 1988-06-09 Maier, Wolfgang, 5630 Remscheid, De
DE19650480A1 (en) * 1996-12-05 1998-06-10 Ofra Struhalla Diamond tool
DE202004010916U1 (en) * 2004-07-12 2005-11-24 Diewe Diamantwerkzeuge Gmbh Drill bit has body which in head or cutting region has in longitudinal or circumferential direction toothed profile with apex line which in side view has height-variable course, especially curvature
CN114183079A (en) * 2021-11-15 2022-03-15 河南黄河旋风股份有限公司 Drill barrel with water adding and slag discharging functions

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2404029A1 (en) * 1974-01-29 1975-08-07 Krupp Ag Huettenwerke PROCEDURE FOR CORE DRILLING OR DRILLING AND DRILL HEAD, IN PARTICULAR PERFORMING THE PROCEDURE
DE2026855B2 (en) * 1969-06-05 1976-07-01 Hougen, Everett Douglas, Flint, Mich. (V.St.A.) TOOL FOR CUTTING DISCS
US4267814A (en) * 1979-12-06 1981-05-19 Federal-Mogul Corporation Abrasive saw blade for trapezoidal grooving
AT373196B (en) * 1980-11-11 1983-12-27 Swarovski Tyrolit Schleif HOLLOW DRILL

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1583845A1 (en) * 1968-02-19 1970-09-24 Zentrales Reparatur Und Ausrue Drill bit for deep, digging, exploration and other drilling
US3537538A (en) * 1969-05-21 1970-11-03 Christensen Diamond Prod Co Impregnated diamond bit
BE874985A (en) * 1979-03-21 1979-07-16 Diamant Boart Sa SURVEY CROWN

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2026855B2 (en) * 1969-06-05 1976-07-01 Hougen, Everett Douglas, Flint, Mich. (V.St.A.) TOOL FOR CUTTING DISCS
DE2404029A1 (en) * 1974-01-29 1975-08-07 Krupp Ag Huettenwerke PROCEDURE FOR CORE DRILLING OR DRILLING AND DRILL HEAD, IN PARTICULAR PERFORMING THE PROCEDURE
US4267814A (en) * 1979-12-06 1981-05-19 Federal-Mogul Corporation Abrasive saw blade for trapezoidal grooving
AT373196B (en) * 1980-11-11 1983-12-27 Swarovski Tyrolit Schleif HOLLOW DRILL

Cited By (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0221548A2 (en) * 1985-11-05 1987-05-13 Disco Abrasive Systems, Ltd. Cutting tool having concentrically arranged outside and inside abrasive grain layers and method for production thereof
EP0221548A3 (en) * 1985-11-05 1988-12-21 Disco Abrasive Systems, Ltd. Cutting tool having concentrically arranged outside and inside abrasive grain layers and method for production thereof
DE8715431U1 (en) * 1986-12-10 1988-04-07 Fa. Herbert Happe, 5600 Wuppertal, De
EP0583629A1 (en) * 1992-08-10 1994-02-23 Bauer Spezialtiefbau GmbH Core bit comprising removable toothed elements with a peripheral distribution
EP0857552A2 (en) * 1997-01-27 1998-08-12 Tyrolit Schleifmittelwerke Swarovski KG Stone cutting element with increased wear resistance
EP0857552A3 (en) * 1997-01-27 2000-02-09 Tyrolit Schleifmittelwerke Swarovski KG Stone cutting element with increased wear resistance
EP0985505A2 (en) * 1998-09-10 2000-03-15 Atock Co., Ltd. Outer-Diameter blade, inner-diameter blade, core drill and processing machines using same ones
EP0985505A3 (en) * 1998-09-10 2003-12-10 Atock Co., Ltd. Outer-Diameter blade, inner-diameter blade, core drill and processing machines using same ones
EP1681151A2 (en) * 1998-09-10 2006-07-19 Atock Co., Ltd. A core drill and processing machines using same
EP1681151A3 (en) * 1998-09-10 2006-07-26 Atock Co., Ltd. A core drill and processing machines using same
GB2423540A (en) * 2005-02-24 2006-08-30 Marcrist Internat Ltd Core drills and cutting discs
GB2423537A (en) * 2005-02-24 2006-08-30 Marcrist Internat Ltd Core drills
GB2423536A (en) * 2005-02-24 2006-08-30 Marcrist Internat Ltd Diamond core drill
GB2423538A (en) * 2005-02-24 2006-08-30 Marcrist Internat Ltd Core drilling segments with side protection
RU168413U1 (en) * 2016-05-18 2017-02-02 Акционерная Компания "АЛРОСА" (публичное акционерное общество) (АК "АЛРОСА" (ПАО)) DRILL BIT

Also Published As

Publication number Publication date
DE3408092A1 (en) 1985-09-19
ATE34329T1 (en) 1988-06-15
DE3562725D1 (en) 1988-06-23
EP0156762B1 (en) 1988-05-18

Similar Documents

Publication Publication Date Title
EP0156762B1 (en) Trepaning cutter
DE2723928C2 (en) Method for producing a bearing ring split at one point on its circumference
DE2920244A1 (en) ROTARY MOWER
EP0104458A2 (en) Centrifuge sieve and process for its production
DE2723382B2 (en) Use of steel fibers as reinforcing fibers for reinforced concrete
EP3037229A1 (en) Drill ring for a core drill bit
DE2627258A1 (en) REAMER FOR EXACTLY Reaming THROUGH HOLES
EP0603121A1 (en) Tubular drill
DE1952217A1 (en) Method for grinding drills for machining metals and alloys
DE2735368C2 (en) Rock drill bit with a carbide drill head
DE3225807C2 (en) Tool for making drill holes in coarse-pored, compressible soils
DE3114687A1 (en) Cutting blade
EP0414280B1 (en) Saw wire fastening
DE3408093A1 (en) Drill bit
DE2151804A1 (en) SHEARING MACHINE WITH ROTATING KNIFE HEAD
DE4036005A1 (en) ROTOR OF AN ULTRASONIC TEST DEVICE FOR ROTATION-SYMMETRICAL TEST PIECES WITH AT LEAST ONE HOLE FOR A TEST HEAD SUPPORT
DE3720203A1 (en) METHOD FOR PRODUCING A SPACE TOOL
EP0995352A1 (en) Conditioning roller and method for making the same for forage harvesters
DE3810230C2 (en)
DE2807198A1 (en) Cup-shaped boring tool mfr. - in which cutters are welded onto rim of cup and end of central drill
DE3311796A1 (en) Device for dividing workpieces
DE1032035B (en) Gapless ring and process for its manufacture
DE2233407A1 (en) MILLING TOOL OD. DGL
EP1117507B1 (en) Grinding tool
DE8321789U1 (en) CUTTING WHEEL

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

AK Designated contracting states

Designated state(s): AT BE CH DE LI

17P Request for examination filed

Effective date: 19851019

17Q First examination report despatched

Effective date: 19870327

GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

AK Designated contracting states

Kind code of ref document: B1

Designated state(s): AT BE CH DE LI

REF Corresponds to:

Ref document number: 34329

Country of ref document: AT

Date of ref document: 19880615

Kind code of ref document: T

REF Corresponds to:

Ref document number: 3562725

Country of ref document: DE

Date of ref document: 19880623

PLBI Opposition filed

Free format text: ORIGINAL CODE: 0009260

26 Opposition filed

Opponent name: TYROLIT SCHLEIFMITTELWERKE SWAROVSKI K.G.

Effective date: 19890218

PLBM Termination of opposition procedure: date of legal effect published

Free format text: ORIGINAL CODE: 0009276

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: OPPOSITION PROCEDURE CLOSED

27C Opposition proceedings terminated

Effective date: 19910730

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: AT

Payment date: 20040113

Year of fee payment: 20

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: CH

Payment date: 20040129

Year of fee payment: 20

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: DE

Payment date: 20040205

Year of fee payment: 20

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: BE

Payment date: 20040409

Year of fee payment: 20

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: LI

Free format text: LAPSE BECAUSE OF EXPIRATION OF PROTECTION

Effective date: 20050124

Ref country code: CH

Free format text: LAPSE BECAUSE OF EXPIRATION OF PROTECTION

Effective date: 20050124

BE20 Be: patent expired

Owner name: *HILTI A.G.

Effective date: 20050125

REG Reference to a national code

Ref country code: CH

Ref legal event code: PL

BE20 Be: patent expired

Owner name: *HILTI A.G.

Effective date: 20050125