Note: Descriptions are shown in the official language in which they were submitted.
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CLAMPING APPARATUS, DRILL STRING COMPONENT AND ROCK DRILLING
RIG.
Field of the invention
The present invention relates to a clamping apparatus, a drill string
component for
use with such a clamping apparatus, and a rock drilling rig including such a
clamping
apparatus.
Background of the invention
In the process of rock drilling, a drill string having a reamer at its free
end has to be
assembled in accordance with the advancement of the reamer into the rock
structure.
Thus drill string components are accordingly joined so as to form the drill
string,
generally by screwing a new drill string component onto a proximal end of the
advanced drill string. After further advancement of the reamer, a new drill
string
component is similarly added to the proximal end of the thus advanced drill
string,
and so on.
Disassembly of the drill string is carried out in the opposite way, i.e. the
drill string is
drawn into the drilling machine under successive loosening of the proximal
drill string
component from the rest of the drill string.
During assembly and disassembling, the drill string components have to be
transported to the assembling area from a drill string component storage and
vice
versa. This transportation may be carried out in a number of ways, e.g. by
hand-
carrying the drill string components, by lifting them by means of lifting
means or by
transporting them on a conveyor, or a combination thereof. In a number of
applications, at least part of the transportation is advantageously carried
out by
means of a hoisting crane. When using a hoisting crane, the drill string
component is
clamped by means of jaw means, e.g. resembling a timber tong, and then
transported
to a desired location. One problem when using such clamping means, however, is
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that a large portion of the drill string component casing has to be accessible
for the
jaw means.
Features of the invention
Some embodiments of the invention relate to a clamping apparatus for use with
a
rock drilling rig, comprising first and second jaw means for jaw gripping a
drill string
component, the clamping apparatus further comprising jaw actuating means,
wherein
said first and second jaw means comprise first and second gripping means,
respectively, for gripping a respective corresponding engagement means of a
respective end portion of the drill string component, said engagement means
being
arranged so as to allow clamping independently of the rotational position of
the drill
string component as seen with respect to its axis of symmetry.
Some embodiments of the invention relate to a drill string component for use
with a
clamping apparatus as described above, wherein the drill string component at
its
ends comprises first and second engagement means, respectively, for receiving
corresponding gripping means of the clamping apparatus, wherein said
engagement
means are arranged so as to allow reception of the corresponding gripping
means
independently of the rotational position of the drill string component as seen
with
respect to its axis of symmetry.
Some embodiments of the invention relate to a rock drilling rig, including a
clamping
device as described above for clamping drill string components when lifting
and/or
transporting the drill string components.
In some embodiments, the clamping apparatus comprises first and second jaw
means for gripping a drill string component, and jaw actuator means, the first
and
second jaw means comprising first and second gripping means, respectively, for
gripping respective corresponding engagement means of a respective end portion
of
the drill string component, wherein said engagement means are arranged so as
to
allow clamping independently of the rotational position of the drill string
component as
seen with
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respect to its axis of symmetry. The engagement means may be
complementary to the gripping means, and/or vice versa.
This has the advantage that the drill string components may be
stacked side by side and on top of each other, and still be
accessible by the clamping apparatus for transport, e.g. to a
derrick.
The clamping apparatus may further comprise means for self
aligning the first and second jaw means with the longitudinal
axis of the drill string component. The means for self
aligning may include a pivoting joint and curved alignment
surfaces on a portion of the first and second jaw means,
respectively.
This has the advantage that no fine adjustment of the gripping
position is necessary. Further, the present invention may be
used in situations where the drill rod components are to be
clamped or released on an inclined surface.
One of said gripping means and said engagement means may
consist of an annular or curved groove or sLot, and the other
of said means may consist of an annular or curved portion from
the group: rib, or one or more projecting parts from the
group: pins. For example, when said engagement means consists
of an annular groove or slot, said gripping means may consist
of said curved portion or at least one of said projecting
parts.
This has the advantage that clamping indeperidently of the
rotational position of the drill string component as seen with
respect to its axis of symmetry may be accomplished in a
relatively easy way.
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Clamping may be arranged to be effected by relatively moving
at least one of said first or second gripping means in a
direction towards the other gripping means, tha direction
substantially corresponding to the longitudinal axis of said
drill string component. The clamping apparatus may further
comprise actuating means for relatively moving at least one of
said first or second gripping means in respect of the other
gripping means by relatively moving at least one of said first
and second jaw means. The actuating means may be constituted
by at least one hydraulic motor, e.g. a hydraulic cylinder, or
a pneumatic motor or an electric motor.
The clamping apparatus may further comprise means for tilting
the drill string component when and/or after clamping the
drill string component. The tilting means may be arranged such
that the tilting angle can be continuously variable, e.g. from
-25 to 25 , from -90 to 90 or from 0 to 25 . The tilting
means may consist of at least one hydraulic motor, e.g. a
hydraulic cylinder, a pneumatic motor or an electric motor.
This has the advantage that it is always possible keep the
drill string component substantially horizontal. with respect
to its longitudinal axis, irrespective of the longitudinal
position of the centre of gravity when transporting the drill
string component. Further, this has the advantage that when
the drill string component is to be positioned on an inclined
surface, the drill string component may be tilted prior to
surface contact so as to ensure a drop-off with minor stress
on the drill string component.
The connection means may consist of a universal joint for
connection to a hoisting crane. This has the advantage that it
reduces stress on the crane jib.
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Brief description of the drawings
Fig. 1 is a section through a drift extending through a rock
and a rock drilling rig therein for drilling a series of
intersecting holes.
5
Fig. 2 shows a front view of the rock drilling of fig. 1.
Figs. 3a-b show a clamping apparatus and a drill string
component according to the present invention.
Figs. 4a-e show various states when clamping a drill stria g
component with a clamping apparatus according to the present
invention.
Figs. 5a-b show self-alignment of the clamping apparatus
according to the present invention.
Detailed description of exemplary embodiments
In figs. 1 and 2 is shown a rock drilling rig 1 suitable or
use with the present invention. In Fig. 1 the rock drilling
rig 1 is shown having at its right end a compartment 5 for
storing drill string components 2' to be assembled into a
drill string. A derrick 8 includes assembling means for
assembling the drill string components into a drill string
which is getting longer during the drilling process. The
assembling means may include a holding wrench.
In fig. 2 is shown a front view of the rock drilling rig i_n an
ongoing drilling process. As is shown, the apparatus 1 is used
to excavate an inclined cylindrical portion of a rock
formation. The drilling is performed by a reamer 3 with a
relatively larger diameter mounted together with a pilot bit 4
of a smaller diameter. The pilot bit is used to ascertain that
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the drilling is performed in a desired direction throughout
the drilling of the particular hole. The reamer 3 is carried
by a drill string 2, at present constituted by drill string
components 2a, 2b, 2c, where additional drill string
components 2d, 2e, etc. (not shown) may be added to the drill
string by the assembling device as the drilling process
progresses until a hole of desired length has been acquired.
Each drill string component 2' may for example be of 1000 mm
length.
Each time a new drill string component has to be added to the
drill string 2, the drill string component has to be moved
from the drill string compartment 5 to the derrick 8.
Conversely, each time a drill string component has to removed
from the drill string, i.e. when drilling of the particular
hole is finished and the drill string is pulled out from the
drilled hole and disassembled, the drill string component has
to be moved from the derrick 8 to the drill string
compartment. The movement of the drill string component may be
carried out in a number of ways, e.g. by moving the components
by means of a conveyor, a hoisting crane or a combination
thereof. In respect of the present invention, the drill string
components are moved at least part of the way by means of a
hoisting crane. In the prior art, this hoisting has been
carried out by using jaw means resembling a timber tong, which
engages the outside surface of the drill string component with
the jaws of the tong. One problem with the use of such
clamping means is, however, as is mentioned above, that a
large portion of the drill string component surface has to be
accessible for the jaws, which makes efficient drill string
component storage difficult. Efficient drill string component
storage is important when the drill string components are
carried on the drilling machine itself, in particular when the
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machine is suited for operation in narrow drifts, such as the
machine described in figs. 1 and 2.
In figs. 3a-b are shown a clamping apparatus 9 according to
the present invention that advantageously may be used together
with hoisting means to move drill string components to/from
the drill string compartment. The clamping apparatus 9
comprises a rotator 10 for coupling to hoisting means, e.g.
via a universal joint 11 as shown in the figure. The rotator
10 is connected to first and second jaw means 12, 13. In the
exemplary embodiment shown in figs. 3a and 3b, the first jaw
means 13 is fixed to the rotator by means of a pivot joint 20.
As is shown in the figure, the first and second jaw means are
mounted on two bars 21, 22. The first jaw means 12 is rigidly
connected to the bars by means of clamp bushings not
explicitly shown, though indicated at 24a-d, and the second
jaw means 13 is slidably mounted on the two bars by means of
sliding bearings 23a-d. As can be seen in the figures, the
first and the second jaw means are thus aligned by means of
the two bars 21 and 22. Further, the first and second jaw
means are coupled together by means of a hydraulic cylinder
25.
The first and second jaw means comprise first and second
gripping means 14, 15, respectively, for gripping respective
corresponding engagement means 16 and 17, located at each end
portion of the drill string component 30.
In the figure, the engagement means 16, 17 consist of an
annular groove at the outer periphery of each drill string
component end. The annular grooves are symmetrical and thus
allow clamping of the drill string component independently of
the rotational position of the drill string component, as seen
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with respect to its axis of symmetry A-A. Further, in fig. 3b,
the gripping means 14, 15 of the jaw means consist of a curved
rib portion in form of e.g. part of a ring, the curvature
corresponding to the curvature of the groove(s) and the height
substantially corresponding to, but not being greater than,
the groove width such that the gripping means may be
introduced into the groove(s) 16, 17. Thus, the gripping means
are complementary to the engagement means.
When clamping the drill string component, the clamping
apparatus 9 is lowered towards the drill string component, as
is shown in fig. 4a. When the clamping apparatus 9 is lowered
such that it abuts against the drill string component 30,
shown in fig. 4b, clamping is effected by relatively moving
the jaw means 12 and 13 towards each other. This is effected
by operating the hydraulic cylinder 25 such that its piston is
pulled into the cylinder housing, which pulls the second jaw
means 13 towards the first jaw means 12, which in turn causes
the first and second gripping means 14, 15 to be introduced
into the corresponding grooves 16, 17 in the drill string
component. The clamping apparatus is now secured to the drill
string component, and the drill string component may be lifted
and transported by connecting suitable hoisting means to the
universal joint 11. Connection of the clamping apparatus to
hoisting means via a universal joint is advantageous since
this reduces stress on e.g. a hoisting crane jib.
The clamping apparatus is further provided with a second
hydraulic cylinder 26. This cylinder, in combination with the
pivoting joint 20, provides the apparatus with the ability to
tilt the drill string component. This is illustrated in figs.
4d, where the drill string component is tilted towards the
left, and in fig. 4e where the drill string component is
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tilted towards the right. In the shown exemplary embodiment,
the tilting angle may be continuously varied from -25 to 25 ,
with respect to a horizontal plane. Of course, other tilting
angle ranges, such as from -90 to 90 or from 0 to 25 , are
possible. As is apparent to a person skilled in the art, a
tilting angle range such as from -90 to 90 requires a
modified tilting mechanism. Performing this modification,
however, is considered to be a skill of the skilled person.
Tilting of the drill sting component makes it possible to keep
the drill string component substantially horizontal with
respect to its longitudinal axis, irrespective of if the
universal joint 11 is vertically aligned with the centre of
gravity of the drill string component. Further, this has the
advantage that when the drill string component is to be
positioned on an inclined surface, the drill string component
may be tilted prior to surface contact so as to ensure a drop-
off with minor stress on the drill string component.
The pivot joint 20 has a further advantage as will be
described in connection with figs. 5a-b. If, as is shown in
fig. 5a-b, the drill string component rests on an inclined
surface, the pivoting joint 20 may be used to self align the
first and second jaw means with the longitudinal axis of the
drill string component. When the clamping apparatus 9 in fig.
5a is lowered towards the drill string component, the clamping
apparatus will first abut against the right most end of the
drill string component as shown in fig. 5a. However, as the
lowering of the clamping apparatus is continued, the pivoting
joint 20 will cause the lowering of the leftmost end of the
clamping apparatus to continue until both the first and the
second jaw means abut, and are aligned with, the drill string
component, shown in fig. 5b, whereupon the drill string
component may be clamped as described above.
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In order to facilitate self alignment, the jaw means may
include guide members 28a, 29a and 29b, shown in fig. 3b.
These members 28a, 29a and 29b are arranged on the surfaces 28
5 and 29 and directed towards the drill string component when
the clamping apparatus is positioned. They are preferably
curved with a radius substantially corresponding to the radius
of the drill string component. The guide members may be
replaceable so as to allow the size and form of the guide
10 members to be varied to allow the clamping apparatus to suite
various drill string components, e.g. drill string components
of different diameters. Also, the position and number of guide
members on the surfaces 28 and 29 may be varied. As an
alternative, the guide members may be omitted, in which case
the surfaces 28 and 29 may be used as alignment surfaces,
preferably curved with a radius substantially corresponding to
the radius of the drill string component.
The above described clamping apparatus further has the
advantage that neither threads used for connecting drill
string components to each other, nor contact surfaces (shown
in fig. 3 on one end of the drill string component, indicated
at 18), which abut each other when drill string components are
to be connected to each other, are subjected to any
interference of gripping means during lifting/transportation
of the drill string components. This is very important since
it is vital to keep these threads and contact surfaces intact
in order to achieve a proper drilling process.
In the above description, the drill string component is
provided with the grooves and the clamping apparatus is
provided with the gripping ribs. In an alternative embodiment,
the drill string component is provided with annular engagement
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ribs, and the clamping apparatus with corresponding recesses
arranged such that a portion of the annular rib fits therein.
Further, the gripping/engagement ribs may instead of ribs be
constituted by other projecting parts, such as e.g. pins.
The above described clamping apparatus may be adapted to fit
drill string components of various lengths, e.g. by varying
the length of the jaw means or the length of the hydraulic
cylinder(s) so that one clamping apparatus may be used for two
or more drill string component lengths.
In the above description the clamping apparatus has been shown
as comprising first and second jaw means, where the second jaw
means is movably connected to the first jaw means, and where
the first jaw means is connected to hoisting means via the
pivoting joint. In an alternative embodiment, the clamping
apparatus further comprises a centre portion which is
connected to the hoisting means, and wherein the first and the
second jaw means are connected to the centre portion via
actuating means and sliding bearings. Alternatively, only one
of the jaw means may be movably connected to the centre
portion, and the other jaw means may be rigidly connected to
the centre portion.
