Note: Descriptions are shown in the official language in which they were submitted.
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METHOD AND DEVICE FOR DRILLING A HOLE IN GROUND OR ROCK
MATERIAL AND FORMING A BRACE
The present invention relates to a method for drilling,
particularly percussion or rotary percussion drilling, a
hole in ground or rock material and forming a brace or
anchorage in said hole, wherein a borehole is formed by a
drill bit mounted on a drill rod assembly, wherein, after
the completion of the borehole, an anchorage is formed by
at least one expanding or spreading element mounted along
the circumference of the drill rod assembly, which
spreading element is brought, particularly expanded, into a
position penetrating into, or resting against, the material
surrounding the borehole, the at least one spreading
element being expanded into the material surrounding the
borehole into a position oriented contrary to a drill-
driving direction. The invention further relates to a
device for drilling, particularly percussion or rotary
percussion drilling, a hole in ground or rock material and
for forming a brace or anchorage in said hole, wherein a
drill bit for forming a borehole is mounted on a drill rod
assembly, wherein at least one expanding or spreading
element is mounted on the outer circumference of the drill
rod assembly and, after the completion of the borehole, is
capable of being brought, particularly expanded, into a
position penetrating into, or resting against, the material
surrounding the borehole, the at least one spreading
element being expandable into a position penetrating the
material surrounding the borehole contrary to a drill-
driving direction after the completion of the borehole.
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In the context of the production of a hole or borehole in
soil or rock material and the subsequent formation or
fixation of an anchorage or lining in the borehole, it is,
for instance, known from WO 98/21439 and WO 98/58132 to
introduce an envelope tube into the borehole during the
drilling procedure, for instance percussion or rotary
percussion drilling, whereupon, after the completion of the
bore, part of the drill bit is optionally removed from the
borehole together with the drill rod assembly, while the
envelope tube remains within the borehole such that an
anchor will subsequently be formed within the borehole by
filling a curing mass into the same. According to the
configuration set out in WO 98/58132, the drill rod
assembly may be provided with additional ribs and grooves
on its outer circumference so as to ensure an accordingly
good anchoring effect in case the drill rod assembly
remains within the borehole, which is subsequently filled.
Alternatively, it is known to remove the drilling tool
together with the drill rod assembly from a borehole after
the production of the borehole, whereupon an anchor or
anchoring device is subsequently introduced into the
borehole, it being, for instance, referred to US 4,305,687
A, US 4,380,407 A, CH 476129 A, WO 94/05900 A, DE 916286 C,
US 4,516,883 A, EP 0354760 A, AT 339239 B and WO
2005/040556 A. In that known prior art, expandable
anchoring elements are introduced into the borehole after
the production of the borehole and subsequent removal of
the drilling device, which expandable anchoring elements,
during the introduction into the borehole, are maintained
at a diameter reduced relative to the borehole, whereupon
expandable subsections of the anchoring device, which are
folded during their introduction or generally reduced in
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terms of cross section, are expanded after the complete
introduction into the borehole. That known prior art
involves the drawback that the borehole has to be made in a
first method step, whereupon, after the removal of the
drilling tool plus drill rod assembly, the anchoring device
is introduced into the optionally very long borehole in a
further method step, whereupon abutment on the borehole
wall is to be subsequently accomplished by widening the
outer diameter of the anchoring device. It is immediately
apparent that not only an accordingly increased amount of
time will be required for the two separate operating steps,
but that an optionally subsequent introduction of such an
anchoring device of great length will entail difficulties.
Furthermore, it is to be anticipated that the removal of
the drilling device together with the drill rod assembly
and the subsequent introduction of an anchoring device is
feasible only in comparatively solid soil or rock, wherein
it must be safeguarded that no material will, for instance,
break into the borehole during the drilling procedure or
after the removal of the drilling tool and prior to the
final introduction of the anchoring device, which material
would block the borehole so as to render the introduction
of the anchoring device impossible.
From DE 19721857 Al, a method and a device of the initially
defined kind can be taken, wherein that known spreading
anchor is aimed to be set without predrilling.
AU-B 676034 discloses an integrated boring and anchor-
setting device, wherein it is aimed to introduce an
expandable element into the surrounding material after
drilling, the expansion of the expandable element being
performed on the rear side of a drill.
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From WO 2006/125242, a method and a device are known,
wherein, after the completion of the borehole, a plurality
of spreading elements are attached into the wall of the
borehole formed by the drill bit.
WO 2006/130889, furthermore, discloses a method and a
device for drilling a hole in soil or rock material and for
introducing an expandable anchoring element, which
anchoring element in that known embodiment is comprised of
a pipe which is, in particular, slotted in the longitudinal
direction.
DE-A 24 31 113 discloses a method and a device for setting
an anchor, which anchor is to comprise a bead-shaped
supporting element that is to have a high pull-back
resistance.
WO 01/11194, moreover, describes a method for fixing a
spreading anchor as well as a spreading anchor, wherein the
anchoring rod and the expandable spreading element are to
enable securement and fixation of the spreading anchor
exceeding a provisional anchoring effect.
In addition, it is, for instance, known to arrange so-
called packers on the outer circumference of a drill rod
assembly of a drilling device, which, after the completion
of the bore, enable an expansion into abutment on the
borehole wall over a short subsection, thus counteracting a
retraction or removal of the drill rod assembly from the
borehole. A reliable anchoring effect, in particular when
providing a plurality of anchors to be adjacently arranged,
in order to ensure the stabilization of surrounding soil or
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rock material will, however, not be achieved by such
packers, thus calling for additional anchoring means, if
required, such as, for instance, the application of a
curable material.
The present invention aims to avoid the problems of the
above-mentioned prior art and to provide a method and a
device of the initially defined kind, which enable a
reliable anchorage at a reduced time expenditure and simple
construction immediately after the completion of a
borehole, wherein the removal of a drilling device and the
separate and subsequent introduction of an anchoring device
are, in particular, to be avoided.
To solve these objects, a method of the initially defined
kind is essentially characterized in that at least one
spreading element, by relative movement along the
longitudinal axis of the drill rod assembly, is expanded
relative to a stop element mounted on the drill rod
assembly so as to be immovable in the axial direction.
Since, upon completion of the borehole, an anchorage is
formed by at least one spreading element mounted along the
circumference of the drill rod assembly, it will be
safeguarded that any additional and time-consuming method
steps for removing the drilling device from the produced or
completed borehole and subsequently introducing and
anchoring or bracing a separate anchoring device, which
have been required when providing a separate anchorage
according to the prior art, will be obviated so as to
enable a direct and reliable anchorage even in possibly
loose material surrounding the borehole, without having to
fear, for instance, the at least partial intrusion of
material into the borehole during the removal of the
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drilling device and the subsequent introduction of the
anchoring device. In this respect, it is provided that the
at least one spreading element is, in particular, expanded
into a position penetrating the material surrounding the
borehole such that no obstruction or impairment by the at
least one expandable spreading element need to be feared
during the drilling procedure, while the at least one
spreading element is placeable and, in particular,
expandable into abutment on the surrounding material, or
into a penetrating position in accordingly loose
surrounding material, after the completion of the borehole.
Such an expandable spreading element can be arranged
relatively close to the drill bit in order to achieve an
accordingly safe anchoring effect immediately behind the
drill bit. In order to achieve a reliable anchoring effect
opposing, in particular, forces acting in the sense of
retracting the anchoring device formed by the drilling
device and, in particular, the drill rod assembly after
having set the at least one spreading element, it is
proposed that the at least one spreading element is
expanded into a position oriented opposite to a drill-
driving direction, into the material surrounding the
borehole. Such an orientation opposite to the drill-driving
direction, of the at least one spreading element will
ensure that, under the action of forces in the sense of
retracting the drilling and anchoring device from the
borehole, the expandable spreading device will more deeply
penetrate the surrounding material and achieve a more
direct and firm abutment on the material delimiting the
borehole, thus increasing or enhancing the anchoring effect
to be achieved by the at least one spreading element. To
support the expansion movement of the at least one
spreading element, it is provided according to the
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invention that the at least one spreading element is
expanded by a relative movement along the longitudinal axis
of the drill rod assembly relative to a stop element which
is mounted on the drill rod assembly so as to be immovable
in the axial direction.
For a particularly reliable expansion of the at least one
spreading element after the completion of the bore or
termination of the drilling procedure, it is provided
according to a further preferred embodiment that the at
least one spreading element is brought into the expanded
position by being acted upon by an element coupled with the
drill rod assembly, at a rotational movement of the drill
rod assembly contrary to a rotational movement for
producing the borehole. It is thus feasible in a simple
manner, merely by reversing the direction of rotation of
the drill rod assembly subsequently forming the anchor or
anchoring rod, to bring the at least one expandable
spreading element into abutment on the material delimiting
the borehole, or into a position penetrating the
surrounding material.
If a further drilling procedure is to be reliably
prevented, and/or the chance of a possibly unintentional
detachment of the anchorage is to be likewise prevented
where necessary, it is proposed according to a preferred
embodiment that, after the expansion of the at least one
spreading element, at least a rotational movement in the
direction of the rotational movement for producing the
borehole is prevented. It will thereby be safeguarded that
a provided mounting of the at least one spreading element
will be safely maintained.
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To solve the above-mentioned objects, a device of the
initially defined kind is, moreover, essentially charac-
terized in that a stop coupled with the drill rod assembly
so as to be immovable in the axial direction at least
during the expansion movement of the at least one spreading
element is provided at a distance from the position of the
at least one spreading element on the outer circumference
of the drill rod assembly, via which stop the at least one
spreading element is expandable. As already pointed out
above, it is thereby feasible in a simple manner without
necessitating the removal of the drilling device and the
subsequent introduction of an anchoring device immediately
after the completion of the borehole or termination of the
drilling procedure, to achieve a safe and reliable
anchoring effect. It is provided that the at least one
spreading element is expandable into a position penetrating
the material surrounding the borehole contrary to the
drill-driving direction after the completion of the
borehole. As already pointed out above, it is thereby, in
particular, feasible to provide an increasing anchoring
effect relative to forces acting in the direction or sense
of retracting the anchor from the borehole. Such an
orientation of the at least one expandable spreading
element contrary to the drill-driving direction, in the
event that a merely provisional anchorage is to be
achieved, whereupon the drilling procedure is to be
continued and the borehole is to be driven further, will,
moreover, safeguard that the at least one expandable
spreading element, at a new reversal of the direction of
rotation of the drill rod assembly in the sense of
continuing the drilling procedure, will again be removed
from the position penetrating the surrounding material, or
abutting position, so as to enable the continuation of the
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drilling procedure without obstruction by the at least one
spreading element while increasing the depth of the
borehole. To support the expansion movement of the at least
one spreading element, it is provided according to the
invention that a stop coupled with the drill rod assembly
so as to be immovable in the axial direction at least
during the expansion movement of the at least one spreading
element is provided at a distance from the position of the
at least one spreading element on the outer circumference
of the drill rod assembly, via which stop the at least one
spreading element is expandable.
For a particularly simple and reliable expansion of the at
least one spreading element, it is provided according to a
preferred embodiment that the at least one spreading
element is expandable into the position penetrating the
material surrounding the borehole by a rotational movement
of the drill rod assembly contrary to a rotational movement
for the production of the borehole. In this context, it is
proposed, for a structurally particularly simple and
reliable configuration, that the at least one spreading
element, at a rotational movement of the drill rod assembly
contrary to the drilling direction, is expandable into the
position penetrating the material surrounding the borehole
via a thread formed on a sleeve-like element cooperating
with the drill rod assembly, as in correspondence with a
further preferred embodiment of the device according to the
invention.
For the reliable introduction of the at least one
expandable spreading element and for the achievement of an
appropriate anchoring effect, it is, moreover, preferably
provided that the at least one spreading element, departing
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from a position substantially abutting the outer
circumference of the drill rod assembly during the drilling
procedure, is at least partially elastically deformed
during the movement penetrating into the material
5 surrounding the borehole.
In order to provide an accordingly uniform expansion
movement so as to achieve the reliable penetration of the
at least one spreading element by the action of low forces
10 even in rough environments, it is, moreover, preferably
proposed that the at least one expandable spreading
element, on its end facing the stop element, is configured
with a ramp or profiling, which cooperates with an, in
particular, complementary ramp or profiling provided on the
stop element.
For the uniform distribution of an anchoring effect about
the circumference of the drill rod assembly, it is,
moreover, preferably proposed according to the invention
that a plurality of expandable spreading elements are
arranged in a manner substantially uniformly distributed
about the circumference of the drill rod assembly.
In order to optionally achieve a reliable anchoring effect
and distribution of forces to be introduced into the
surrounding material via an anchor of greater length, which
is formed by the drill rod assembly, it is, moreover,
proposed that a plurality of expandable spreading elements
are provided about the circumference of the drill rod
assembly at different distances from the drill bit, as in
correspondence with a further preferred embodiment of the
device according to the invention.
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In order to avoid any interference with, or impairment of,
the drilling procedure and to secure the position of the
spreading element during the drilling procedure, it is,
moreover, preferably provided that the at least one
spreading element is secured in its position substantially
abutting the drill rod assembly by an additional retaining
element during the drilling procedure.
In order to introduce the displacement forces required for
expanding the spreading element upon termination of the
drilling procedure as well as, in addition, to reliably
introduce the forces required for percussion or rotary
percussion drilling, it is further proposed that a bush
mounted on the drill rod assembly and equipped with an
external toothing is provided for transmitting the
rotational movement from the drill rod assembly onto the
drill bit, which bush, for the expansion of the at least
one spreading element, is placeable into a position out of
engagement with the toothing of the drill bit, or an
element coupled with the drill bit, as in correspondence
with a further preferred embodiment of the device according
to the invention. Such a bush or toothed bush can be built
in an accordingly massive and structurally simple manner as
a function of the forces to be introduced both during the
drilling procedure and during the expanding procedure.
To further support a desired expansion procedure of the at
least one spreading element, it is, moreover, provided that
the at least one spreading element, during the expansion
procedure, is guided on the drill rod assembly and/or an
element coupled with the drill bit by a linear guide
extending substantially in the longitudinal direction of
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the borehole, as in correspondence with a further preferred
embodiment of the device according to the invention.
As already mentioned above, it may be desired or possible
to perform a drilling procedure after a temporary expansion
of the spreading element by effecting a rotational movement
of the drill rod assembly in the original direction of
rotation for the production of the borehole. If such a
further drilling procedure is to be reliably prevented
while optionally also providing a reliable anchorage of the
at least one spreading element without any chance of
detachment of the latter, it is proposed according to a
preferred embodiment that sleeve-like or bush-like elements
mounted on the drill rod assembly are provided to at least
prevent a rotational movement in the direction of the
rotational movement for the production of the borehole,
which sleeve-like or bush-like elements are formed with
respectively complementary elevations or profilings on
mutually facing end faces.
In the following, the invention will be explained in more
detail by way of exemplary embodiments schematically
illustrated in the attached drawing. Therein:
Fig. 1 illustrates a partial longitudinal section through a
device according to the invention for carrying out the
method of the invention during the drilling procedure,
wherein at least one spreading element is substantially in
abutment on the drill rod assembly;
Fig. 2 depicts the device according to the invention for
carrying out the method of the invention in an illustration
similar to that of Fig. 1, with the at least one spreading
element being expanded into the material surrounding the
borehole;
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Fig. 3, in an illustration similar to that of Fig. 1,
represents a partial longitudinal section through a
modified embodiment of a device according to the invention
for carrying out the method of the invention, wherein, in
particular, locking against any further rotational movement
is provided; and
Fig. 4 is an exploded view of individual elements of the
embodiment according to Fig. 3 which are provided to
achieve rotational locking and surround the drill rod
assembly.
In the embodiment illustrated in Figs. 1 and 2, a drill rod
assembly is generally denoted by 1, which has a corrugated
or thread-like shape, particularly on its outer surface, to
serve as an anchoring rod after the completion of the
borehole. During the drilling procedure indicated in Fig.
1, the transmission of a rotational movement of the
anchoring rod or drill rod assembly 1, which is imparted by
a driving means not illustrated and arranged outside the
borehole 2, is effected via an end face 3 of a sleeve-
shaped element 4 coupled with the drill rod assembly 1,
which end face 3 cooperates with a bush or toothed bush 5
having an external toothing 6, which is coupled with an
element or tappet 8 coupled with the drill bit 7 so as to
transmit a rotational movement of the drill rod assembly 1
via the toothed bush 5 onto the tappet 8 and hence the
drill bit 7, cutting or drilling elements being indicated
by 9 and 10. The toothed bush 5 provided for transmitting
the rotational movement is maintained in a position resting
against the end face 3 by a spring 11.
During the drilling procedure, at least one subsequently
expandable spreading element 12 is substantially in abut-
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ment on the outer contour of the drill rod assembly or
anchoring rod 1 so as to prevent any interference with, or
impairment of, the drilling procedure by the at least one
expandable spreading element 12 during the drilling
procedure.
A central axis of the drill rod assembly 1, and hence the
entire drilling device, is denoted by 13.
After the completion of the borehole 2, the drill head or
drill bit 7 is pressed at the interior of the borehole in
the sense of the drill-driving direction or arrow 14,
whereupon the drill rod assembly 1 is set into a rotational
movement contrary to the driving direction for performing
the drilling procedure.
By reversing the rotational movement, the end face 3 of the
sleeve-like element 4 is moved out of engagement with an
end face denoted by 15 in Fig. 2, of the toothed bush 5,
which is displaced against the force of the spring 11 in
such a manner as to cause the external toothing 6 of the
toothed bush 5 to get out of engagement with a complemen-
tary toothing of the tappet 8 coupled with the drill bit 7
and no more rotational movement or torque to be transmitted
from the drill rod assembly 1 to the drill bit 7.
The sleeve-like element 4 coupled with the drill rod
assembly or anchoring rod 1 comprises a thread 16 on its
outer surface, which, upon reversal of the direction of
rotation of the drill rod assembly 1, causes the at least
one expandable element or spreading element 12, which
comprises a complementary thread 17, to be moved contrary
to the drill-driving direction, which coincides with the
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application direction 14 of the drill head 7 in Fig. 2,
along the outer surface of the drill rod assembly 1 as
indicated by arrow 18. For a substantially linear movement
of the at least one expandable element 12, a linear guide
19, 20 is, moreover, provided on the outer surface of the
spreading element 12 and also in the subsection 21 of the
tappet 8, which covers the spreading element 12,
particularly during the drilling procedure.
For a selective expansion movement of the spreading element
12 into the material 22 surrounding the borehole wall 2, a
stop 23 is additionally provided on the outer circumference
of the drill rod assembly or anchoring rod 1 at a distance
from the mounting of the spreading element 12. For a
reliable guidance of the expansion movement, which can be
achieved by the spreading element 12 penetrating the
surrounding material 22, it is, moreover, provided that the
spreading element 12 comprises a ramp or profiling 24 which
cooperates with a substantially complementary ramp or
profiling 25 of the stop element 23 in such a manner as to
effect the expansion and penetration of the spreading
element 12 and, in particular, its tip 26 into the
surrounding material 22 by the linear movement of the
spreading element 12 along arrow 18, which is caused by the
rotational movement via the mutually cooperating threads 16
and 17.
As indicated, the stop 23 is, moreover, coupled with a
locking sleeve 27.
In order to prevent the at least one spreading element 12
from breaking during the expansion movement, or in the
expanded position, as illustrated in Fig. 2, an elastically
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deformable region 28 of the spreading element 12 is
additionally provided.
Due to the fact that the at least one expandable spreading
element 12 penetrates into, or comes into abutment on, the
surrounding material 22 against the drill-driving direction
indicated by arrow 14, it will be ensured that the at least
one expandable spreading element 12 will penetrate more
deeply into the surrounding material 22, or come more
firmly into abutment on the borehole wall 2, by the action
of forces in the sense of arrow 18 indicating an extraction
direction of the drill rod assembly or anchoring rod 1,
thus providing elevated forces opposing any extraction.
In addition, the orientation of the at least one spreading
element 12 opposite to the drill-driving direction 14
ensures that the present configuration may, for instance,
also be used to achieve a provisional securement or
anchorage, since a new reversal of the direction of
rotation of the drill rod assembly or anchoring rod 1 in
the sense of the drill-driving direction via the toothed
bush 5 will cause recoupling of the drill rod assembly 1
with the drill bit 7 or the tappet 8, respectively, so as
to enable the drilling procedure to be continued while the
spreading element 12, due to the orientation of the
mutually cooperating threads 16 and 17 is, at the same
time, retracted into the position illustrated in Fig. 1 so
as not to interfere with, or impair, a further drilling
procedure.
For the uniform distribution of anchoring forces to be
absorbed, a plurality of spreading elements 12 may be
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arranged or provided substantially uniformly about the
circumference of the drill rod assembly 1.
In order to provide for securement in a position
substantially abutting the drill rod assembly 1 during the
drilling procedure, a securing ring 29 is, moreover,
indicated in Fig. 1, which, during the drilling procedure,
will, for instance, hold a plurality of uniformly
peripherally distributed spreading elements 12
substantially in abutment on the drill rod assembly 1.
For the distribution of anchoring forces to be absorbed,
along a drilling device 1 optionally having a greater
length, it may, moreover, be provided that a plurality of
spreading elements 12 are arranged or provided at different
axial distances from the drill bit 7 and, in a favorable
manner, substantially uniformly about the circumference of
the drill rod assembly 1.
In addition, it may be provided that an envelope tube not
illustrated in the drawings is, for instance, arranged
immediately consecutive to the tappet coupled with the
drill bit 7, or the element 8, so as to enable the at least
one spreading element 12 and, in a favorable manner, a
plurality of spreading elements 12 to emerge into the
position illustrated in Fig. 2 through appropriate passage
openings or slots in order to achieve an appropriate
anchoring effect.
It has thus become possible to expand the at least one
spreading element 12 into an anchoring or securing position
as illustrated in Fig. 2 immediately upon completion of the
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borehole 2 by simply reversing the direction of movement or
rotation of the drill rod assembly or anchoring rod 1.
In the embodiment according to Figs. 3 and 4, the reference
numerals of the preceding embodiments have been retained
where possible. Also this configuration comprises an
anchoring rod formed by a drill rod assembly 1, which, as
will be discussed below, is provided with an external
thread not illustrated, said anchoring rod or drill rod
assembly 1 powering a drill bit again denoted by 7 in order
to produce the borehole 2.
In the embodiment illustrated in Figs. 3 and 4, a bush 30
similar to bush 5 is provided for transmitting the
rotational movement of the drill rod assembly or anchoring
rod 1 to the drill bit 7 as in the embodiment according to
Figs. 1 and 2, said bush 30 cooperating with a bush 31
comparable to element 4 in order to transmit a rotational
movement onto a tappet 32, which will subsequently impart a
rotational movement to the drill bit 7. In addition, a
further sleeve-like or bush-like element 33 cooperating
with the drill bit 7 is provided in the embodiment
illustrated in Figs. 3 and 4, wherein both the drill bit 7
and the sleeve-like element 33 comprise elevations or
profilings 34 and 35, respectively, which will slide one
above the other in the manner of a ratchet during the
drilling procedure, thus enabling a rotational movement or
drill-driving movement while effecting locking of the drill
bit 7 during a rotational movement of the anchoring rod or
drill rod assembly 1 contrary to the drilling device by the
additionally provided application via a spring 36.
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In order to achieve an appropriate locking effect, also the
bushes or sleeves 30 and 31 in a similar manner are each
provided with respectively complementary elevations or
profilings 37 and 38, respectively, which will likewise
cause locking at a reversal of the rotational movement.
Furthermore, an additional sleeve-like element 39 coupled
with the element 32 is provided, which is coupled via a
further sleeve-like element or socket 40 arranged within
the same, wherein both the element 39 and the element 40
cooperate with the spreading element denoted by 41 during a
reversing movement. It is, in particular, apparent from the
illustration according to Fig. 4 that the socket-like or
sleeve-like spreading element 41 is formed with a plurality
of longitudinally extending slots 42 which, upon actuation
of the drill rod assembly 1 contrary to the rotational
movement for producing the borehole, cooperate with one
another via complementary ramps 43 and 44, respectively, of
the spreading element 41 and of a stop element 45 so as to
enable the expansion of the individual spreading elements
41' into an expanded position contrary to the drill-driving
direction.
In order to reliably avoid an optionally desired further
rotational movement after the expansion of the spreading
elements 41', also the sleeve-like or bush-like elements
39, 40 and the spreading element formed by a socket-like or
sleeve-like element 41 are likewise each formed with
complementary elevations or profilings 46, 47 and 48 in a
manner similar to the sleeve-like elements 30, 31, 33 as
well as the drill bit 7, in order to effect rotational
locking as a function of the orientation to be provided. In
this respect, it is to be anticipated that the element 40
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will directly screw on a right-hand thread on the anchoring
rod or drilling thread 1 and directly move on the anchoring
rod or drill rod assembly 1 for expanding the spreading
element 41 or the individual subsections 41', and the
spreading element 41 will move over the stop element 45,
thus causing the expansion of the spreading elements 41' by
a relative movement of the ramps 43 and 44.
In addition, the element 40 is mounted within the element
39 in a longitudinally displaceable, yet rotationally fast
manner such that, taking into account the profilings or
elevations or end toothings 46, 47 and 48, the respective
end toothings or profilings 47 and 48 will cause rotational
locking of the individual elements in the event that
element 40 emerges from element 39 during the expansion
movement of the spreading elements 41', such that locking
of the reached position of the spreading elements 41' will
be achievable by the provision of the respective end
toothings or profilings.
If locking of the spreading elements 41' is optionally
renounced, the respective profilings will be obviated.
