Boring or penetrating the earth – With tool drive prime mover or above-ground mechanical... – With installing casing
Reexamination Certificate
2002-08-23
2004-04-20
Bagnell, David (Department: 3672)
Boring or penetrating the earth
With tool drive prime mover or above-ground mechanical...
With installing casing
C175S257000, C175S305000
Reexamination Certificate
active
06722454
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a device for drilling, in particular percussion drilling or rotary percussion drilling, boreholes, including a drill bit having a drilling or working surface, a drill rod assembly for introducing a rotation and/or percussion stress and for introducing a flushing and cooling fluid into the drill bit, and a jacket tube which defines a hollow space between the drill rod assembly and the interior of the jacket tube and is supported on the drill rod assembly and connectable with the drill bit, wherein the jacket tube in a drilling position is arranged at a distance from the drill bit rear side facing away from the working surface.
DESCRIPTION OF THE PRIOR ART
Such devices for drilling, in particular percussion drilling or rotary percussion drilling, boreholes are known in various embodiments, whereby the haulage of the excavated material or drillings has to be ensured in any event. Embodiments of such drilling devices are known, wherein, in a modification of the initially defined embodiment, no jacket tube or cladding tube is used such that the haulage of the excavated material may simply be effected in a free space provided around the drill rod assembly, the drill rod assembly usually having smaller external dimensions than the drill bit defining or making the borehole.
A device according to the type mentioned above can be taken for: example from DE-C 40 06 320, aiming in particular at providing of boreholes with tubes. DE-C 44 32 710 discloses a target drilling device for horizontal drilling aiming at a proper drilling through obstacles.
In an embodiment of the initially defined kind, in which a jacket tube or cladding tube is used in addition, the haulage of the excavated material or drillings may be effected outside the jacket tube, if the latter has an accordingly reduced external diameter relative to the drill bit, whereby, however, only comparatively small free spaces will usually be formed in such cases such that only relatively small size excavated material can be transported off in those regions. Since in devices of the initially defined kind jacket tubes are usually used whose external dimensions differ only slightly from the external dimensions of the drill bit because the jacket tube is to provide an at least partial support or provisional lining of the borehole, in particular in the case of broken rocks, the haulage of excavated material or drillings in such devices in which a comparatively large passage is defined between the drill rod assembly and the interior of the jacket tube is effected through that free space or hollow space or annular space provided between the drill rod assembly and the interior of the jacket tube, reference in this context being made, for instance, to AT-B 390 303, EP-B 0 670 950 or WO 98/20229. In addition to the usually known passage openings provided for a flushing and cooling fluid, which are located in the foremost section or on the working surface of the drill bit, at least one further passage opening must, however, be usually provided in those known embodiments, either on the working surface of the drill bit or in a lateral portion thereof, in order to enable the introduction of the excavated material or drillings to be transported off, into the free space or hollow space defined by the drill rod assembly and the interior of the jacket tube, and subsequently enable the delivery of the excavated material through that hollow space. It is immediately apparent that in such a manner only very small size material can be transported off, since it is feasible to provide only comparatively small passage openings in the region of the drill bit and in a consecutive region between the drill bit and the jacket tube in order to enable the introduction of excavated material into the hollow space provided between the drill rod assembly and the jacket tube. Moreover, there is a great risk of obstructions of such passage openings which may give rise to haulage problems of, in particular lumpy or granular, excavated material and call for a further disintegration of the already excavated material in order to enable its introduction and passage through the passage openings in the region of the drill bit for removing the same, wherein it is immediately apparent that such an additional disintegration work to be performed by the drill bit will decelerate the drilling progress as a whole.
SUMMARY OF THE INVENTION
Departing from a device of the initially defined kind, the present invention aims to provide a device for drilling, in particular percussion drilling or rotary percussion drilling, boreholes, which facilitates the haulage of excavated material or drillings known per se, through a hollow space or annular space defined by the drill rod assembly and the interior of the drill rod and which enables excavated material, in particular excavated material having also larger dimensions to be readily introduced into, and delivered through, that hollow space or annular space.
To solve these objects, the device for drilling, in particular percussion drilling or rotary percussion drilling, boreholes is essentially characterized in that the drill bit in a flushing position for the hollow space provided between the jacket tube and the drill rod assembly is placeable with its rear side in abutment on the jacket tube front end facing the drill bit and/or connectable with the front end of the jacket tube and that a locking element is provided in the interior of the drill bit, which, in the drilling position, clears at least one passage opening ending in the working surface and, in the flushing position, for discharging the flushing fluid into the interior of the hollow space between the jacket tube and the drill rod assembly, clears at least one passage opening leading towards the rear side. Due to the fact that the jacket tube in a drilling position is arranged at a distance from the drill bit, a free space is made available behind the drill bit, viewed from the working surface of the drill bit, which free space leaves an accordingly large passage opening for the introduction of the excavated material or drillings into the hollow space or annular space provided between the drill rod assembly and the jacket tube so as to enable comparatively coarse material tuned to the dimensions of this jacket tube to be readily introduced into the hollow space and transported off through the same. Thus, as opposed to the initially discussed known prior art, the device according to the invention does not require additional passage openings in the region of the working surface of the drill bit, or in a lateral region thereof, in order to enable the introduction of excavated material behind the drill bit and into the hollow space defined between the drill rod assembly and the interior of the jacket tube, so that weakening of the drill bit will be avoided and the obstructions and blockages occurring at those haulage openings in the known embodiments need not be feared, in particular. It is, thus, feasible in the region of the working surface to do with the known passage openings for the cooling and flushing fluid, which are usually provided in comparatively smaller numbers and have comparatively smaller passage cross sections, too. In order to enable flushing or the selective haulage of the material to be transported off in the annular space or hollow space provided between the drill rod assembly and the interior of the jacket tube, it is, furthermore, provided, according to the invention, that the rear side of the drill bit in such a flushing position is placeable in abutment on the jacket tube front end facing the drill bit and/or connectable with the front end of the jacket tube so as to immediately enable the selective and defined flushing of this hollow space or annular space by the introduction of the cooling or flushing fluid also into this annular space or hollow space. In order to ensure, in case at least one additional passage opening is provided in the region of the rear side of the drill bit, that this passage opening w
Bonm Karl
Mocivnik Josef
Bagnell David
Jacobson & Holman PLLC
Smith Matthew J
Techmo Entwicklungs- und Vertriebs GmbH
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