Note: Descriptions are shown in the official language in which they were submitted.
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Extendable cylinder, drill head, and method
The invention relates to an extendable cylinder, in particular an extendable
cylinder for a
drill head. The invention further relates to a drill head comprising an
extendable cylinder,
and a method of operating a drill head.
Devices and methods for installing ground anchoring systems, including
drilling rock or
tensioning rock bolts or other connectors, for example, are known from US
8,770,323 B2,
US 7,950,309 B2, WO 2005/103450 Al, GB 382,678, WO 2013/104021 Al or WO
2013/104019 Al. However, further improvements of the devices and methods are
sought.
For example, safety and ease of handling are important fields for
improvements, as well
as versatility of area of application and interaction.
Therefore, it is an object of the present invention to provide an extendable
cylinder, a drill
head and a method of operating a drill head, which are improved over existing
solutions
with respect to at least one of the above-mentioned goals.
This object is solved by an extendable cylinder, in particular for a drill
head, comprising a
shaft with a shaft ring volume between an inner part and an outer part of the
shaft; a
piston with a piston ring volume between an inner part and an outer part of
the piston; the
piston being moveable with respect to the shaft along a longitudinal axis; a
proximal end
of the outer part of the piston being arranged between the inner and outer
part of the
shaft; and a distal end of the inner part of the shaft being arranged between
the inner and
outer part of the piston; and wherein the extendable cylinder is extendable
and/or
retractable along the longitudinal axis.
The extendable cylinder can be used for a drill head or together with a drill
head, for
example. The extendable cylinder comprises a shaft and a piston, with the
extension of
the cylinder being realized by a translational movement of the piston relative
to the shaft
along a longitudinal axis. A retraction of the extendable cylinder is realized
by a
translational movement of the piston relative to the shaft in an opposite
direction. The
extendable cylinder has a proximal end and a distal end. In particular, when
the
extendable cylinder is used in a drill head, the proximal end of the
extendable cylinder
would be the end connected to the drill head and the distal end would be the
end
connected to a functional drill element, like a drill steel, for example.
The translational movement of the piston with respect to the shaft preferably
is a guided
movement or a sliding movement, which preferably is controlled by an extension
union for
controlling the movement, for example the speed, and/or extent, and/or
direction of the
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movement. Preferably, the extendable cylinder is extendable by at least 100
mm, in
particular by at least 110, 120, 130, 140, 150, 160, 170, 180, 190, or 200 mm.
The piston and/or the shaft preferably have a substantially cylindrical shape
in at least a
region or portion. The inner and outer part of the shaft and/or the inner and
outer part of
the piston preferably are arranged coaxially with respect to the longitudinal
axis. Further
preferably, the inner part of the shaft circumscribes an inner or interior
shaft volume and
the inner part of the piston circumscribes an inner or interior piston volume.
The shaft and the piston of the extendable cylinder are arranged such that a
proximal end
of the outer part of the piston is positioned between the inner and outer part
of the shaft
io and a distal end of the inner part of the shaft is arranged between the
inner and outer part
of the piston.
Preferably, a distal end of the piston ring volume is closed, for example by a
connection
between the inner and outer part of the piston. Further preferably, a proximal
end of the
shaft ring volume is closed, for example by a connection between the inner and
outer part
of the shaft. The shaft ring volume and the piston ring volume may be in fluid
communication with each other.
This construction of an extendable cylinder in which inner and outer parts of
the shaft and
inner and outer parts of the piston intertwine provides for a very versatile
extendable
cylinder with characteristics allowing the application of the extendable
cylinder in a wide
range of applications, thereby increasing the functionality of the extendable
cylinder itself
and, for example, a drill head with such an extendable cylinder.
According to a preferred embodiment, the piston and the shaft are connected by
a
torsionally rigid coupling. A torsionally rigid coupling is to be understood
as a connection,
which does not allow for a relative rotational movement between the piston and
the shaft.
This means that when the shaft is rotated, the piston is rotated together with
the shaft and
vice versa. This embodiment has the advantage that the extendable cylinder is
particularly suitable for use or application in a drill head, where the
rotation is applied to
the extendable cylinder and shall be transferred from the shaft to the piston,
for example.
It is further preferred that the torsionally rigid coupling is realized by a
connection of the
outer part of the piston and the inner part of the shaft. This position of the
torsionally rigid
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coupling is particularly preferred since it creates a reliable coupling and
has a minimized
impact on the functionality and suitability of the extendable cylinder.
It is further preferred that the torsionally rigid coupling is a spline
coupling and/or a latch
coupling. Further torsionally rigid couplings may be applied.
Preferably, the splines of a spline coupling run parallel to the longitudinal
axis to allow for
a sliding movement of the piston relative to the shaft. Further preferably,
the spline
coupling has a longitudinal extension, which allows for a reliable torsionally
rigid coupling
independent from the relative position of the piston to the shaft, i.e. along
the whole
extension distance of the extendable cylinder.
io In a further preferred embodiment, the extendable cylinder is extendable
and/or
retractable by provision and/or discharge of hydraulic fluid to and/or from
the shaft ring
volume and/or the piston ring volume. In this embodiment, the extendable
cylinder can be
referred to as a hydraulic cylinder. The construction of the extendable
cylinder is
particularly suitable for realizing the extension and/or retraction by
hydraulic fluid, since
the shaft ring volume and/or the piston ring volume can be used for the
hydraulic fluid. As
a hydraulic fluid, in particular hydraulic oil can be used.
It is further preferred that the proximal end of the outer part of the piston
is sealed against
the outer part of the shaft; and the proximal end of the inner part of the
piston is sealed
against the inner part of the shaft.
Preferably, high-pressure seals for sealing against the leakage of hydraulic
fluid are
provided to realize the sealing. Further preferably, the seals are provided as
sliding seals,
which reliably seal in any relative position of the piston with respect to the
shaft. With
these seals, the shaft ring volume and the piston ring volume can be
efficiently sealed
against an inner or outer periphery or environment.
Further preferably, the shaft ring volume and the piston ring volume are in
fluid
communication with each other, preferably via the coupling between the outer
part of the
piston and the inner part of the shaft. This embodiment is particularly
preferred in
combination with the realization of the extendable cylinder as a hydraulic
extendable
cylinder.
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It is further preferred that an intermediary ring volume is provided between
the outer part
of the piston and the outer part of the shaft; wherein the extendable cylinder
is retractable
by provision of hydraulic fluid to the intermediary ring volume.
Preferably, the extension of the extendable cylinder is initiated by the
provision of
hydraulic fluid to the shaft ring volume and/or the piston ring volume, while
the retraction
of the extendable cylinder is realized by the provision of fluid to a further
ring volume,
namely the intermediary ring volume. Preferably, the intermediary ring volume
is separate
from the shaft ring volume and the piston ring volume, i.e. the intermediary
ring volume
preferably is not in fluid communication with the shaft ring volume and the
piston ring
volume. When hydraulic fluid is provided to one ring volume to initiate a
movement of the
piston, hydraulic fluid preferably is discharged from another ring volume to
allow for this
movement.
Preferably, the intermediary ring volume is at least partly formed by a
section of the outer
part of the piston with a reduced outer diameter. Further preferably, the
intermediary ring
volume surrounds at least a section of the outer periphery of the outer part
of the piston.
Preferably, the intermediary ring volume is closed at its distal end and/or
its proximal end
and further preferably is provided with seals, in particular high-pressure
sliding seals for
hydraulic fluid.
A further preferred embodiment of the extendable cylinder is characterized by
at least one
force transmission element between the outer part of the piston and the outer
part or the
shaft for transmitting lateral forces in at least one direction different from
a direction
parallel to the longitudinal axis.
A force transmission element is preferred to provide additional stability
particularly in a
fully or partly extended position of the extendable cylinder. In particular,
the force
transmission element is adapted to transmit lateral forces substantially
orthogonal to the
longitudinal axis. Lateral forces are to be understood as forces in at least
one direction
different from a direction parallel to the longitudinal axis. In particular,
lateral forces are
forces substantially orthogonal to the longitudinal axis. The force
transmission element
preferably is connected to the outer radial periphery of the outer part of the
piston.
In a preferred embodiment, the at least one force transmission element is a
ring-shaped
element with an axial extension which exceeds its radial extension by at least
a factor of
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two, and which is connected to the outer part of the piston by form fit. A
form fit can be
understood to be a positive fit or interlocking fit or a connection via
corresponding cross
sections.
This embodiment of the force transmission element has the advantage that it is
a
5 particularly cost efficient and reliable embodiment, which is also easy
to assemble and
manufacture.
Preferably, two ring-shaped force transmission elements are provided. The
axial
extension of the force transmission element preferably is 3, 4 or 5 times
larger than its
radial extension. Preferably, the force transmission element is made of hard
plastic.
io In a preferred embodiment, the outer radial periphery of the at least
one force
transmission element is arranged flush with the remaining outer radial
periphery of the
outer part of the piston surrounding the at least one force transmission
element.
A further preferred embodiment of the extendable cylinder is characterized by
a supply
channel forming a central cavity for supplying a fluid to the piston. The
fluid can be a
liquid, like water, for example. This allows for wet, moist or dry drilling
operation. It is
preferred that all elements of a drill head, in particular all elements of the
extendable
cylinder, and/or a multi-functional connector that may come into contact with
water or
other aggressive fluids have adequate protective coatings, in particular rust
persistent
coatings.
The provision of a supply channel for supplying fluid to the piston further
increases the
versatility of the extendable cylinder, for example for the application of wet
or moist
drilling, when a liquid or mist is supplied through the supply channel.
Preferably, the
supply channel is arranged within the inner part of the piston and further
preferably
arranged coaxially with the piston and the shaft. A distal end of the supply
channel
preferably is sealed against the inner part of the piston. A distal end of the
supply channel
may project in a distal direction from a distal end of the shaft.
According to a further aspect, the objective is solved by a drill head,
comprising an
extendable cylinder as described above; a drive for rotationally driving the
shaft of the
extendable cylinder; an extending union adapted to extend and/or retract the
extendable
cylinder along the longitudinal axis; a connector, preferably a multi-
functional connector,
at a distal end of the piston for connecting a functional drill element
thereto.
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Preferably, the extending union is a rotating union in fluid communication
with the shaft
ring volume and/or the piston ring volume and/or the intermediary ring volume,
the
rotating union being adapted to provide and/or discharge hydraulic fluid to
and/or from the
shaft ring volume and/or the piston ring volume and/or the intermediary ring
volume.
Further it is preferred that the drill head comprises at least one speed
sensor, preferably,
arranged at a spur gear reduction stage.
Further preferably, the drill head comprises a temperature sensor and/or
pressure sensor
and/or a thread breaker.
As to the advantages, preferred embodiments and details of the drill head and
its
io preferred embodiments, reference is made to the corresponding aspects and
embodiments described above, in particular with respect to the cylinder.
According to a further aspect, the object is solved by a method of operating a
drill head as
previously described, comprising connecting a functional drill element to the
connector at
the distal end of the piston; rotating the extendable cylinder by rotationally
driving the
shaft; extending and/or retracting the extendable cylinder along the
longitudinal axis.
According to a preferred embodiment, the method of operating a drill head
further
comprises removing the functional drill element from the connector; connecting
another
functional drill element to the connector.
As to the advantages, preferred embodiments and details of the method of
operating a
drill head and its preferred embodiments, reference is made to the
corresponding aspects
and embodiments described above, in particular with respect to the cylinder
and the drill
head.
The extendable cylinder preferably is applied in a combination with a multi-
functional
connector and its preferred embodiments described below.
A preferred multi-functional connector for connecting a functional drill
element to a drill
head, in particular to an extendable cylinder of a drill head, comprises a
first connecting
element with a first receptacle adapted for receiving a connecting section of
the first
functional drill element therein, a second connecting element arranged
proximal to the
first connecting element in a direction of a longitudinal axis of the multi-
functional
connector with a second receptacle adapted for receiving a connecting section
of the
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second functional drill element therein, a retainer element arranged between
the first and
the second connecting element with a retainer opening for receiving the
connecting
section of the second functional drill element therethrough, wherein the first
receptacle
has at least two driving surfaces for transferring a torque in a first
direction to at least two
corresponding contact surfaces on the connecting section of the first
functional drill
element, the second receptacle has at least two driving surfaces for
transferring a torque
in a first direction and in a second, opposite direction to at least two
corresponding
contact surfaces on the connecting section of the second functional drill
element in a drill
and/or retracting position of the second functional drill element, and the
retainer element
io has at least one retaining section to prevent a movement of the
connecting section of the
second functional drill element in a direction parallel to the longitudinal
axis relative to the
second connecting element in the retracting position of the second functional
drill
element.
The multi-functional connector is adapted to connect a functional drill
element thereto,
while at the same time the multi-functional connector is preferably adapted to
be
connected to a drill head, in particular to an extendable cylinder of a drill
head. In this
way, a functional drill element can be connected to the drill head via the
multi-functional
connector. In particular, the multi-functional connector is adapted to connect
different
functional drill elements to a drill head. A first functional drill element
can be connected to
the multi-functional connector via the first receptacle of the first
connecting element, while
the second functional drill element can be connected to the multi-functional
connector via
the second receptacle of the second connecting element. Preferably, the first
and second
functional drill elements are different from each other. For example, the
connecting
section of the first and second functional drill elements may have different
cross-sectional
shapes. Further, the first and second functional drill elements may have
different
functions, such as a drill steel and a tightening rod, for example.
Preferably, only one
functional drill element may be connected to the multi-functional connector at
a time.
The connecting sections of the first and second functional drill elements
preferably are
received in the first and second receptacle preferably via corresponding cross
sections, in
particular via a form fit or positive fit or interlocking fit. Further
preferably, the first and
second receptacle are only so much bigger than the corresponding connecting
section of
the first and second functional drill elements to allow for the insertion and
release of the
respective functional drill element.
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Both the first and the second receptacle have at least two driving surfaces
for transferring
a torque to at least two corresponding contact surfaces on the respective
connecting
sections of the first and second functional drill element.
The at least two driving surfaces of the first receptacle are suitable for
transferring a
torque in a first direction to the corresponding contact surfaces on the
connecting section
of the first functional drill element. This means that a first functional
drill element received
in the first receptacle can be driven or rotated in the first direction via
the multi-functional
connector. This can be particularly preferred when the first functional drill
element is a
tensioning rod or an anchor nut, for example.
io The at least two driving surfaces of the second receptacle are adapted
to transfer a
torque in a first, and in a second, opposite direction to the corresponding
contact surfaces
on the connecting section of the second functional drill element. In
particular, the second
receptacle is arranged such that a second functional drill element received in
the second
receptacle can be rotated via the multi-functional connector in the first
direction when the
connecting section of the second functional drill element is in a drill
position, and can be
rotated in the second, opposite direction when the connecting section of the
second
functional drill element is in the retracting position. This can be
particularly preferred when
the second functional drill element is a drill steel, for example, and the
multi-functional
connector is connected to a drill head, wherein the drill steel needs to be
rotated in the
first direction to drill and rotated in the second direction during retraction
of the drill steel.
The drill position and the retracting position of the second functional drill
element differ
preferably in their rotational orientation relative to the longitudinal axis
LX. A rotation
torque or driving movement is to be understood as a rotation, torque or
driving movement
about the longitudinal axis. Preferably, the transfer of torque in the first
direction
corresponds to a drill position of the second functional drill element and the
transfer of
torque in the second, opposite direction corresponds to a retracting position
of the second
functional drill element.
The second connecting element is arranged proximal to the first connecting
element.
Preferably, the proximal arrangement of this second connecting element
relative to the
first connecting element means that when the multi-functional connector is
arranged at a
drill head, the second connecting element is proximal or closer to the drill
head than the
first connecting element.
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Between the two connecting elements a retainer element is arranged which has a
retainer
opening through which the connecting section of the second functional drill
element can
be put through. In order to insert the connecting section of the second
functional drill
element into the second receptacle, the connecting section of the second
functional drill
element preferably is first inserted into the first receptacle of the first
connecting element,
then passed through the retainer opening of the retainer element and finally
inserted into
and received in the second receptacle of the second connecting element.
The at least one retaining section of the retainer element has the function to
retain the
connecting section of the second functional drill element in its retracting
position. That
io means that a translational movement of the second functional drill
element relative to the
retainer element is prevented, in particular a translational movement parallel
or along the
longitudinal axis in a distal direction. This has the advantage that in the
retracting
position, the retaining section of the retainer element ensures that the
second functional
drill element is removed together with the multi-functional connector and is
not released
from the second receptacle when the multi-functional connector is moved into
the distal
direction.
Preferably, the at least one retaining section does not prevent a movement of
the
connecting section of the second functional drill element in a direction
parallel to or along
the longitudinal axis relative to the second connecting element in the drill
position or in a
further, neutral position of the second functional drill element. Preferably,
the second
functional drill element is inserted into the second receptacle in the drill
position or in a
further, neutral position. In the drill and/or the neutral position, it is
preferred that the
connecting section of the second functional drill element can pass the
retainer element
with its at least one retaining section easily and without obstruction of the
path of
translational movement parallel to or along the longitudinal axis. In the
retracting position
of the second functional drill element, however, this relative translational
movement of the
connecting section of the second functional drill element relative to the
second receptacle
is prevented by the at least one retaining section of the retainer element
In this way, the multi-functional connector has the advantage of being adapted
to receive
two functional drill elements (preferably one at a time) and further to
transfer torque in a
first direction to the two functional drill elements and further to apply a
torque in a second,
opposite direction to the second functional drill element in a retracting
position and to
further retain the second functional drill element in this retracting
position. In this way, the
multi-functional connector, for example, can be used with a drill head and a
drill steel to
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drill an anchor hole, for example, and the same multi-functional connector can
be used ¨
after removal of the drill steel ¨ to tighten an anchor nut. In particular,
dollies or adapters
necessary in existing solutions to attach a tightening rod, for example, to a
drill head are
not necessary with this multi-functional connector.
5 In a preferred embodiment, the second receptacle has at least two first
driving surfaces
for transferring a torque in a first direction to at least two corresponding
first contact
surfaces on the connecting section of the second functional drill element in a
drill position
of the second functional drill element, and the second receptacle has at least
two second
driving surfaces for transferring a torque in a second, opposite direction to
at least two
io corresponding second contact surfaces on the connecting section of the
second
functional drill element in a retracting position of the second functional
drill element.
In this embodiment, the second receptacle has at least four driving surfaces,
namely at
least two first driving surfaces and two second driving surfaces. The first
driving surfaces
are arranged to transfer a torque to two corresponding first contact surfaces
on the
connecting section of the second functional drill element and at least two
second driving
surfaces are arranged to transfer a torque in the second direction to at least
two
corresponding second contact surfaces. In this embodiment, preferably, the
transfer of
torque in the first and second direction via the second receptacle is realized
by two
different sets of driving surfaces contacting two different sets of
corresponding contact
surfaces on the connecting section of the second functional drill element.
Preferably, the first and second driving surfaces are arranged alternating
along a
periphery, preferably an inner periphery, of the second receptacle.
It is further preferred that between pairs of first and second driving
surfaces rounded
corners are arranged along the periphery of the second receptacle. This
embodiment has
the advantage that the insertion and removal of the connecting section of the
second
functional drill element from the second receptacle is facilitated. It further
facilitates the
transition from the drill position to the retraction position and vice versa
of the connecting
section of the second functional drill element.
Preferably, two adjacent first and second driving surfaces are arranged under
an angle
toward each other or, in other words, a first driving surface is inclined to
an adjacent
second driving surface.
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Preferably, the at least two driving surfaces of the first and second
receptacles as well as
the at least two corresponding contact surfaces on the connecting section of
the first and
second functional drill elements extend parallel to the longitudinal axis.
It is further particularly preferred that the first driving surfaces and/or
the second driving
surfaces of the second receptacle are arranged to engage a connecting section
of the
second functional drill element with a square cross section. For example,
drill steels
typically have a connecting section with a square cross section. It is
therefore preferred
that the second receptacle is arranged to engage such a connecting section of
a second
functional drill element with a square cross section. However, the second
receptacle can
io also be arranged to engage a connecting section of a second functional
drill element with
other cross sections, for example rectangular, hexagonal, triangular, or other
polygonal or
partly or fully rounded cross-sectional shapes.
In a further preferred embodiment, the retainer element has at least two
retaining sections
to prevent a movement of the connecting section of the second functional drill
element in
a direction parallel to the longitudinal axis relative to the second
connecting element in
the retracting position of the second functional drill element.
It is particularly preferred that the retainer element has more than one
retaining section, in
particular two, three, four or more retaining sections. Preferably, the
retaining sections are
uniformly spaced from each other. It is further preferred that the retaining
sections are
spaced corresponding to the second driving surfaces.
Further preferably, the first receptacle has a hexagonal cross sectional
shape. A
hexagonal cross-sectional shape of the first receptacle is particularly
preferred since
tightening rods or anchor nuts typically have a connecting section with a
hexagonal cross-
sectional shape. Alternatively, the first receptacle may have a square,
triangular,
rectangular, or other hexagonal or partly or fully rounded cross-sectional
shape.
It is further preferred that an inner envelop of the cross section of the
first receptacle
envelops the cross section of the second receptacle and/or the retainer
opening.
This embodiment is advantageous to facilitate the insertion and removal of the
connecting
section of the second functional drill element through the first receptacle
the retainer
opening into the second receptacle. In this embodiment, the open cross section
of the
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first receptacle fully encompasses the open cross section of the retainer
opening and/or
the second receptacle.
In a further preferred embodiment, the retainer element has at least two
guiding surfaces.
Preferably, the at least two guiding surfaces are arranged such that
corresponding
contact surfaces of the connecting element of the second functional drill
element are
guided by the at least two guiding surfaces while the connecting section of
the second
functional drill element is passing through the retainer element. It is
further preferred that
the at least two guiding surfaces extend parallel to the longitudinal axis.
Further preferably, between the at least two guiding surfaces a rounded corner
is
arranged. This embodiment facilitates the insertion and/or removal of the
connecting
section of the second functional drill element through the retainer opening.
Further preferably, the at least two guiding surfaces are arranged to engage a
connecting
section of the second functional drill element with a square cross section in
an orientation
according to the drill position. This embodiment is particularly preferred
when a second
functional drill element in the form of a drill steel with a square cross
section in its
connection section is used. The guiding surfaces are particularly advantageous
when
they are arranged to guide contact surfaces on the connecting section of the
second
functional drill element while it is passed through the retainer element in
the drill position.
In a further preferred embodiment, the multi-functional connector comprises an
engagement element arranged at an outer periphery of the first connecting
element and
adapted to engage a cylinder of a drill head in a torsion proof way. The
provision of an
engagement element and its function to connect the multi-functional connector
in a
torsion-proof way to a cylinder of a drill head has the advantage that the
rotation of the
cylinder of the drill head can be transferred to the multi-functional
connector and in this
way, via the multi-functional connector, also to the first or the second
functional drill
element connected thereto.
The engagement element preferably connects the outer periphery of the first
connecting
element to the cylinder of a drill head via corresponding cross sections, form
fit, positive
fit or interlocking fit.
In a further preferred embodiment, the multi-functional connector comprises a
fluid
provision section with a fluid channel for providing fluid from a proximal end
of the
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connector to the first connecting element and/or the second connecting element
and/or
the retainer element. Preferably, the fluid provision section is adapted to be
connected to
a fluid channel of a cylinder of a drill head, in particular an extendable
cylinder of a drill
head, preferably via a seal for a sealed connection. Further preferably, the
fluid provision
section provides a stop phase of the second receptacle at its proximal end
such that a
connection section of a second functional drill element received in the second
receptacle
is stopped in a proximal direction by the fluid provision section.
According to a further aspect, the objective is solved by a drill head,
comprising an
extendable cylinder with a shaft and a piston, the piston being moveable with
respect to
the shaft along a longitudinal axis; a drive for rotationally driving the
shaft of the
extendable cylinder; an extending union adapted to extend and/or retract the
extendable
cylinder along the longitudinal axis; a multi-functional connector as
previously described
at a distal end of the piston for connecting a functional drill element
thereto.
As to the advantages, preferred embodiments and details of the drill head and
its
preferred embodiments, reference is made to the corresponding aspects and
embodiments described above, in particular with respect to the multi-
functional connector.
According to a further aspect, a method for drilling an anchor hole and for
tightening an
anchor nut is provided, comprising providing a drill head with a multi-
functional connector
as previously described, providing a drill steel as a first functional drill
element, inserting
the drill steel trough the first receptacle and the retainer opening into the
second
receptacle in the drill position, rotating a cylinder of the drill head with
the multi-functional
connector in a first direction, rotating the cylinder of the drill head with
the multi-functional
connector in a second, opposite direction to bring the drill steel into the
retracting position,
retracting the cylinder with the connector and the drill steel, rotating the
cylinder of the drill
head with the multi-functional connector in the first direction to bring the
drill steel into the
drill position, removing the drill steel from the multi-functional connector,
engaging the
anchor nut of an anchor with the first receptacle, rotating a cylinder of the
drill head with
the multi-functional connector in a first direction
As to the advantages, preferred embodiments and details of the method for
drilling an
anchor hole and for tightening an anchor nut and its preferred embodiments,
reference is
made to the corresponding aspects and embodiments described above, in
particular with
respect to the multi-functional connector and the drill head.
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Preferred embodiments of the invention shall now be described with reference
to the
attached drawings, in which
Fig. 1: a longitudinal cross section of a drill head with an extendable
cylinder and a
multi-functional connector in the extended position;
Fig. 2: a longitudinal cross section of the drill head of Fig. 1 in the
retracted position;
Fig. 3: a three-dimensional depiction of the drill head according to Fig.
1 cut in the
longitudinal direction;
Fig. 4: a three-dimensional depiction of the drill head according to Fig.
2 cut in the
longitudinal direction;
Fig. 5: a three-dimensional depiction of the drill head according to Fig.
2;
Fig. 6: an enlarged view of Fig. 5 without the first connecting element
and the
retainer element;
Fig. 7: an enlarged view of Fig. 5 without the first connecting element;
Fig. 8: a three-dimensional depiction of the drill head according to Fig.
1;
Fig. 9: a three-dimensional depiction of the drill head according to Fig.
2;
Fig. 10: a three-dimensional depiction of the drill head cut in the area
of the taper
bearings;
Fig. 11: a three-dimensional depiction of the drill head cut in the area
of the spur
gear reduction stage;
Fig. 12: a three-dimensional depiction of the drill head cut in the area of
the fluid or
water connection; and
Fig. 13: a three-dimensional depiction of the drill head in the area of
the motor
connections.
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In Figs. 1 ¨ 13, a preferred example of a drill head 2000 with an extendable
cylinder 10
and a multi-functional connector 1000 is shown. Although in the figures, the
multi-
functional connector 1000, the extendable cylinder 10 and the drill head 2000
are shown
in combination, in particular the multi-functional connector 1000 and the
extendable
5 cylinder 10 described herein also can be applied separately.
Figs. 1, 3, and 8 show the drill head 2000 with the extendable cylinder 10 in
the extended
position, while Figs. 2, 4, and 9 show the drill head 2000 with the extendable
cylinder 10
in its retracted position. Figs. 5 ¨ 7 show in particular details of the multi-
functional
connector 1000. Figs. 10¨ 13 in particular show details of the drill head
2000.
10 The drill head 2000 comprises a hydraulic motor 2100 for driving the
extendable cylinder
10 connected with it via the spur gear reduction stage 2300. The extendable
cylinder 10
is supported by taper roller bearings 2400 arranged back to back. The
hydraulic motor
2100 is able to operate in two different speeds. The torque of the hydraulic
motor 2100 is
transferred to the cylinder 10 via a spur gear reduction stage 2300. The two
rings of taper
15 roller bearings 2400 are adapted to receive the loads and forces coming
from operation of
the drill head 2000. The drill head 2000, in particular the hydraulic motor
2100, is adapted
to provide a rotation of the extendable cylinder 10 of up to 700 rpm and to
apply a torque
in the first and/or second direction of up to 400 Nm and a flow of hydraulic
oil of up to 40
l/m in.
The extendable cylinder 10 can be extended in a distal direction (d) by the
provision of
hydraulic fluid, as described below. The drill head 2000 comprises an
extending union
2200 in the form of a rotating union for providing the hydraulic fluid to the
rotating
extendable cylinder 10. The multi-functional connector 1000 is connected to a
distal end
of the extendable cylinder 10.
The extendable cylinder 10 comprises a shaft 100 and a piston 200, which is
movable
relative to the shaft 100 along a longitudinal axis LX to extend or retract
the extendable
cylinder 10. The shaft has an inner part 110 and an outer part 120 and the
piston has an
inner part 210 and an outer part 220. The shaft 100 with its inner and outer
parts 110, 120
and the piston 200 with its inner part 210 and its outer part 220 are
substantially
cylindrical in shape and arranged coaxially.
A shaft ring volume 101 is formed between the inner part 110and the outer part
120 of the
shaft and a piston ring volume 201 is formed between the inner part 210 and
the outer
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part 220 of the piston 200. A proximal end 221 of the outer part 220 of the
piston 200 is
arranged between the inner and outer part 110, 120 of the shaft 100 and sealed
against
the outer part 120 of the shaft 100. A distal end 111 of the inner part 110 of
the shaft 100
is arranged between the inner and outer parts 210, 220 of the piston 200. The
proximal
end 221 of the inner part 210 of the piston 200 is sealed against the inner
part 110 of the
shaft 100.
The piston 100 and the shaft 200 are connected by a torsionally rigid coupling
30, which
is realized by a spline coupling between the outer part 220 of the piston 200
and the inner
part 110 of the shaft 100. The splines of the spline coupling 30 extend in a
direction
parallel to the longitudinal axis LX. The spline coupling 30 has a
longitudinal extension
large enough to provide for a reliable torsionally rigid coupling between the
shaft 100 and
the piston 200 in the extended as well as in the retracted position, in
particular when the
hydraulic motor 2100 drives the extendable cylinder 10 in a rotational
movement.
The shaft ring volume 101 and the piston ring volume 201 are in fluid
communication with
each other via the spline coupling 30.
By providing a hydraulic fluid via hydraulic fluid bores 2500 to the shaft
ring volume 101
and/or the piston ring volume 201, the extendable cylinder 10 can be extended,
this
means brought from a position shown in Figs. 2 or 4 into the position shown in
Figs. 1 or
3. The extendable cylinder 10 can be retracted by the provision of hydraulic
fluid via
hydraulic fluid bores 2500 to the intermediary ring volume 40. The
intermediary ring
volume 40 is preferably formed by a section 222 of the outer part 220 of the
piston 200,
which has a reduced outer diameter. Preferably, when hydraulic fluid is
provided to the
shaft and/or piston ring volume 101, 201, hydraulic fluid is retracted from
the intermediary
ring volume 40 and vice versa to allow for or facilitate the respective
retraction or
expansion movement.
Further, seals 300, in particular high-pressure seals where hydraulic fluid is
applied, are
arranged throughout the drill head 2000 and the extendable cylinder 10 with a
multi-
functional connector 1000 where needed. The high-pressure seals 300, in
particular
water seals and/or hydraulic fluid seals, preferably are adapted to withstand
a fluid
provision of 6 l/min at up to 180 bar.
The extendable cylinder 10 further comprises a supply channel 140 forming a
central
cavity 141 for supplying a fluid, for example water, to the piston 200, in
particular an inner
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piston volume 212. A fluid, like water, can be supplied to the supply channel
140 via a
fluid connection 2600. The supply channel 140 also has a substantially
cylindrical shape
and is arranged coaxially with the piston 200 and the shaft 100 and provided
with
respective seals 300 to create a sealed fluid channel.
Further, the extendable cylinder 10 comprises a transmission element 130 to
transmit
lateral forces. The transmission element 130 is arranged between the outer
part 220 of
the piston 200 and the outer part 120 of the shaft 100.
The force transmission element 130 is a ring-shaped element with an axial
extension that
exceeds its radial extension by a factor larger than 3. Further, the force
transmission
element 130 is connected to the outer part 220 of the piston 200 by form fit.
The rotating union 2200 is in fluid communication with the shaft ring volume
101 and/or
the piston ring volume 201 and/or the intermediary ring volume 40 and adapted
to provide
and/or discharge hydraulic fluid from these volumes.
Fig. 10 shows in particular a ring of taper roller bearings 2400 as well as
hydraulic fluid
bores 2500 for providing hydraulic fluid to the piston, ring, and/or
intermediary ring
volume 201, 101, 40 for moving the piston 200. The spur gear reduction stage
2300 can
be seen in particular in Fig. 11. Fig. 11 further shows speed sensors 2700 of
the drill head
2000 to control the speed of the rotation. Fig. 12 shows in particular the
fluid or water
connection 2600 to provide fluid, like water, to the central cavity 141 of the
supply
channel 140. Fig. 13 shows in particular the hydraulic fluid bores 2500
providing the
motor with hydraulic oil.
The multi-functional connector 1000 is connected to the outer part 220 of the
piston 200
via a threaded connection 1700. To ensure that the threaded connection 1700 is
not
released during rotation of the extendable cylinder 10 with the multi-
functional connector
1000 in a first or second, opposite direction, the multi-functional connector
is secured via
an engagement element 1400. The engagement element 1400 is arranged at an
outer
periphery of the first connecting element 1100 and adapted to engage the
piston 200, in
particular the outer part 220 of the piston 200 in a torsion proof way, in
particular via a
form fit, interlocking fit or positive fit. As can be seen in particular from
Fig. 5, the
engagement element 1400 has six evenly spaced recesses in its outer
circumference and
six corresponding protrusions on the distal end of the outer part 220 of the
shaft 200
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project into these recesses. The engagement element 1400 can be secured by a
ring or
e-clip 1600.
The multi-functional connector 1000 comprises a first connecting element 1100,
a second
connecting element 1300 and a retainer element 1200. The first connecting
element has
a first receptacle 1110 to receive a connecting section of a first functional
drill element
therein. Also the second connecting element 1300 has a second receptacle 1310
to
receive a connecting section of a second functional drill element therein. The
second
connecting element 1300 is arranged proximal (p) to the first connecting
element 1100
and the retainer element 1200 is arranged between the first and second
connecting
elements 1100, 1200. The retainer element 1200 has a retainer opening 1210 to
receive
the connecting section of the second functional drill element therethrough.
The first receptacle 1110 has a hexagonal cross-sectional shape and is
particularly
suitable to engage an anchor nut or tensioning rod. The first receptacle 1110
has six
driving surfaces 1111 for transferring a torque in a first direction to at
least two
corresponding contact surfaces on the connecting section of the first
functional drill
element.
The second connecting element 1300 further has a fluid provision section 1500
with a
cylindrical fluid channel for providing fluid from a proximal end of the multi-
functional
connector 1000 to the first and second connecting elements 1100, 1300 and the
retainer
element 1200.
The second receptacle 1310 is particularly suitable to engage a second
functional drill
element in the form of a drill steel with a connecting section having a square
cross
section. The second receptacle 1310 has four first driving surfaces 1311 for
transferring a
torque in a first direction to at least two corresponding first contact
surfaces on the
connecting section of the second functional drill element in a drill position
of the second
functional drill element. The second receptacle 1310 further has four second
driving
surfaces 1312 for transferring a torque in a second, opposite direction to at
least two
corresponding second contact surfaces on the connecting section of the second
functional drill element in a retracting position of the second functional
drill element. The
first and second driving surfaces 1311, 1312 of the second receptacle 1310 are
arranged
alternating along a periphery of the second receptacle 1310. Between pairs of
first and
second driving surfaces 1311, 1312 rounded corners 1313 are arranged along the
periphery of the second receptacle 1310. As can be seen in Fig. 6, four
rounded corners
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1313 are present in the second receptacle 1310 of the embodiment shown in the
figures.
Two adjacent first and second driving surfaces 1311, 1312 are preferably
arranged under
an angle toward each other or, in other words, the first driving surface 1311
is inclined to
an adjacent second driving surface 1312. The first and second driving surfaces
1311,
1312 of the second receptacle 1310 are arranged to engage a connecting section
of the
second functional drill element with a square cross section.
The retainer element 1200 can be seen in particular in Fig. 7. The retainer
element 1200
has at least two retaining sections 1213 to prevent a movement of the
connecting section
of the second functional drill element in a direction parallel to the
longitudinal axis LX
io relative to the second connecting element 1300 in the retracting
position of the second
functional drill element.
The retainer element 1200 has four guiding surfaces 1211, wherein between
adjacent
guiding surfaces 1211 a rounded corner 1212 is arranged (in total four rounded
corners).
The four guiding surfaces 1211 are arranged to engage a connecting section of
the
second functional drill element with a square cross section in an orientation
according to
the drill position, in order to let the connecting section of the second
functional drill
element pass the retainer opening 1210 in its drill position. In the drill
position, the
connecting section of the second functional drill element would contact the
first driving
surfaces 1311 of the second receptacle 1300 and the guiding surfaces 1211 of
the
retainer element 1200. In the retracting position of the connecting section of
the second
functional drill element, only the second driving surfaces 1312 of the second
receptacle
1300 would be contacted by the connecting section of the second functional
drill element,
which would be retained in a longitudinal direction by the retaining sections
1213 of the
retainer element 1200.
As can be seen in particular from Fig. 5, an inner envelope of the cross
section at the first
receptacle 1110 envelopes the cross section of the second receptacle 1310 as
well as
the cross section of the retainer opening 1210.
With the drill head 2000 comprising an extendable cylinder 10 and a multi-
functional
connector 1000 as described before, a method for drilling an anchor hole and
for
tightening an anchor nut can be improved and facilitated. For example, a drill
steel as a
first functional drill element with a connecting section with a square cross
section can be
inserted through the first receptacle 1110 and the retainer opening 1210 into
the second
receptacle 1310 in a drill position. The extendable cylinder 10 can then be
rotated by the
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hydraulic motor 2100 in a first direction, which results in a corresponding
rotation of the
drill steel via the first driving surfaces 1311 to drill the anchor hole. When
the desired
length of the anchor hole is reached, the extendable cylinder 10 can be driven
by the
hydraulic motor 2100 into a second, opposite direction with the drill steel in
the retracting
5 position. Then the drill steel can be retracted together with the
extendable cylinder 10 and
the multi-functional connector 1000 from the anchor hole, while the retaining
sections
1213 of the retainer element 1200 of the multi-functional connector 1000
prevent a
relative longitudinal movement of the drill steel relative to the multi-
functional connector
1000. To remove the drill steel from the multi-functional connector 1000, the
cylinder 10 is
10 rotated by the hydraulic motor 2100 in the first direction, to bring the
drill steel into the drill
position and to release it from the retaining sections 1213 of the retainer
element 1200.
When the drill steel is removed from the multi-functional connector 1000, a
tensioning rod
can be connected to the first receptacle 1110 or an anchor nut of an anchor
can be
engaged by the first receptacle 1110. It can be preferred to extend the piston
200 relative
15 to the shaft 100 before the anchor nut is engaged or before the
extendable cylinder 10 is
then rotated in the first direction to tighten the anchor nut of the anchor.
By providing the multi-functional connector 1000 and by providing an
extendable cylinder
10, the same drill head 2000 can be used for drilling the anchor hole and for
tightening an
anchor nut without the use of dollies or other adapters. This increases safety
and
20 facilitates handling. It further provides for a higher degree in
automation of the process of
drilling an anchor hole and tightening an anchor nut.
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REFERENCE SIGNS
LX longitudinal axis
d distal
P proximal
cylinder
30 torsionally rigid coupling
40 intermediary ring volume
100 shaft
101 shaft ring volume
110 inner part of the shaft
111 distal end of the inner part of the shaft
120 outer part of the shaft
130 transmission element
140 supply channel
141 central cavity
200 piston
201 piston ring volume
202 distal end of the piston
210 inner part of the piston
212 inner piston volume
220 outer part of the piston
221 proximal end of the outer part of the piston
300 seals
1000 multi-functional connector
1100 first connecting element
1110 first receptacle
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1111 driving surfaces of first receptacle
1200 retainer element
1210 retainer opening
1211 guiding surfaces
1212 rounded corners
1213 retaining sections
1300 second connecting element
1310 second receptacle
1311 first driving surfaces of the second receptacle
1312 second driving surfaces of the second receptacle
1313 rounded corners
1400 engagement element
1500 fluid provision section
1600 ring
1700 threaded connection
2000 drill head
2100 hydraulic motor
2200 extending union
2300 spur gear reduction stage
2400 taper roller bearings
2500 hydraulic fluid bores
2600 fluid connection
2700 speed sensors
