Note: Descriptions are shown in the official language in which they were submitted.
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Drill bit magazine, drill bit holder, and method for changing
drill bit in rock drilling unit
Background of the invention
[0001] The invention relates to a magazine to which replaceable drill
bits for a rock drilling machine tool may be stored. A drill bit may be
fastened to
a drill rod belonging to the tool by means of a drill bit changer. The
magazine
has several spaces for storing drill bits, and a movable frame part, and each
space supporting a drill bit is arrangeable one at a time into a changing
station
in the magazine for the purpose of taking a drill bit from the magazine and
bringing one into it.
[0002] The invention further relates to a drill bit holder and to a
method for handling a drill bit.
[0003] The subject matters of the invention are described in more
detail in the preambles of the independent claims.
[0004] In rock drilling, a rock drilling machine is used with a tool
connected thereto which can be rotated around its longitudinal axis and
through which impact pulses may be delivered to the rock being drilled so that
the rock will break and a drill bore will be formed. The tool may comprise one
or more drill rods and a replaceable drill bit connected to its outermost end.
Typically, the leading end of the drill bit is equipped with several bit
buttons
that penetrate the rock being drilled. The drill bit experiences wear and is
oc-
casionally also damaged, because very high loads are directed to it during
drill-
ing. Thus, it is necessary to change the drill bit at times so as to ensure
the
quality and efficiency of drilling. Changing drill bits manually by the
operator is
difficult and slow, and what is worse, also dangerous. Thus, drill bit
changers
have been developed so as to mechanize the changing. Present ways of stor-
ing and handling drill bits do not, however, fully satisfy the requirements of
us-
ers. For instance, US publication 4 065 845 discloses a drill bit changer in
which the drill bits are arranged against spaces in a magazine, which sets re-
strictions on the shape and dimensioning of the drill bits.
Brief description of the invention
[0005] It is an object of the present invention to provide a novel and
improved magazine and drill bit holder for storing and handling drill bits. An-
other object is to provide a novel and improved method for changing drill
bits.
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[0006] The drill bit magazine of the invention is characterised in that
each space in the magazine is arranged to detachably receive and connect
one separate drill bit holder, that each stored drill bit is arranged to be
sup-
ported by means of the drill bit holder into the magazine, and that the drill
bit
holder is supported against at least one inside surface of the drill bit.
[0007] The drill bit holder of the invention is characterised in that the
drill bit holder is a separate projecting piece that is supportable against at
least
one inside surface of the drill bit, and that the drill bit holder comprises a
grip-
ping part for handling and fastening the drill bit holder.
[0008] The method of the invention is characterised by arranging inside
each drill bit a projecting drill bit holder that is a separate piece from the
maga-
zine, handling each drill bit being replaced during transfers and storage by
only
affecting the drill bit holder, and taking the drill bit holder out of the
drill bit be-
fore the drill rod and drill bit are connected to each other.
[0009] The idea of the invention is that during storage and transfer
of drill bits, a projecting drill bit holder is arranged inside them to
support
against at least one inside surface of the drill bit. It is then not necessary
to
affect the outer surface of the drill bits during storage in the magazine and
transfer between the magazine and retainer. The drill bit holder is a kind of
adapter between the drill bit and magazine, and between the drill bit and
trans-
fer device. However, the drill bit holder does not participate in fastening
the drill
bit to a tool, but may act as a detachable and independent transfer and
storage
adapter.
[0010] The invention provides the advantage that by means of the
drill bit holder, it is possible to store and handle without difficulty drill
bits of dif-
ferent shapes and external dimensions. The same magazine and transfer de-
vice may then be used to handle different drill bits. This adds to the
functional
adaptability of the drill bit changer for using different drill bits. This, in
turn, pro-
vides cost savings, since it is possible to manufacture a universal magazine
and transfer device that may be widely utilised in rock drilling equipment in-
tended for various drilling situations. Another advantage is that arranging
the
drill bit to a desired location with the retainer is easier, since the outer
circum-
ference of the drill bit is free of a gripping device or the like of the
transfer de-
vice.
[0011] The idea of an embodiment is that the frame part of the
magazine is a disc-like piece that is equipped with several fastening holes,
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each of which is arranged to receive one drill bit holder. Each fastening hole
opens toward the outer circumference of the disc-like frame part. The drill
bit
holder comprises a fastening part with fastening grooves so that the drill bit
holder may be supported by means of the grooves to the fastening hole and
moved in the changing station in the direction of the radius of the disc-like
frame part. Further, the moving of the drill bit holders in the direction of
the
frame part radius away from the fastening space is prevented when not at the
changing station. The disc-like frame part of the magazine is turnable
relative
to a turning axis for moving the drill bit holders relative to the changing
station.
[0012] The idea of an embodiment is that a drill bit stored in the
magazine is supported to the frame of the magazine solely by means of the
drill bit holder.
[0013] The idea of an embodiment is that the drill bit holder has a
gripping part with which the separate drill bit holder is fastened detachably
to
the magazine. Further, the drill bit holder may be transferred between the
magazine and drilling centre by gripping the gripping part with the transfer
de-
vice.
[0014] The idea of an embodiment is that the gripping part of the
drill bit holder is at the free end of the holder.
[0015] The idea of an embodiment is that the drill bit holder com-
prises an elongated arm having on the portion of its first end a cylindrical
grip-
ping part. The gripping part has a longitudinal hole to which a transfer pin
of
the transfer device belonging to the drill bit changer may be pushed for at-
tachment to the drill bit changer. Further, the outer surface of the gripping
part
has a circumferential fastening groove, by which the drill bit holder may be
fas-
tened to the magazine.
[0016] The idea of an embodiment is that the drill bit holder com-
prises an elongated arm and at least two support pieces that are arranged to
support themselves against internal connection threads of the drill bit. The
first
support piece is arranged to be movable relative to the arm and the second
support piece is arranged on the portion of the outermost end of the arm sta-
tionary relative to the arm. The support pieces may then be set at an axial
dis-
tance to each other and correspondingly against each other by moving the arm
in relation to the first support piece.
[0017] The idea of an embodiment is that the drill bit holder com-
prises at least one adjusting member for setting the maximum axial distance
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between the first support piece and second support piece to correspond to the
drill bit being handled. By means of the adjustment, drill bits of different
lengths
may be set into the magazine so that the leading ends of the drill bits are es-
sentially level with each other. The leading ends of the drill bits may then
be
supported in the magazine in the axial direction against a suitable support
plate or the like, whereby the drill bits will not detach from the drill bit
holders,
even though the drilling unit and magazine were directed downward. Further,
when the leading ends of the drill bits are adjusted to be essentially level
with
each other and when the magazine is at the retainer, the transfers of drill
bits
between the retainer and magazine may be done using a simple crosswise
linear movement.
[0018] The idea of an embodiment is that the first support piece of
the drill bit holder comprises a cylindrical portion that may be arranged
inside
the drill bit, and a shoulder that may be arranged against the rear surface of
the drill bit.
[0019] The idea of an embodiment is that the top part of the drill bit
holder is arranged to support itself against the bottom of a hole in the drill
bit
and to support the drill bit in the axial direction. Thus, one support piece
of the
drill bit holder may be arranged to handle the axial support and the other sup-
port piece may be arranged to support the drill bit to be parallel to the
drill bit
holder.
[0020] The idea of an embodiment is that the first and second sup-
port pieces of the drill bit holder are detachable pieces, whereby they may be
changed to correspond to the drill bit being handled at each time.
[0021] The idea of an embodiment is that at least two different drill
bits that differ in outer dimensions or shape from each other are stored and
handled with the drill bit changer simultaneously. The differing drill bits
are
supported into the magazine by means of similar drill bit holders. Widely
differ-
ent drill bits, even for special drilling situations, may be stored inside the
magazine without structural changes.
[0022] The idea of an embodiment is that there is a shape lock be-
tween the drill bit holder and gripping member of the transfer device. The
shape-locking is opened when the drill bit holder is inserted into the
magazine.
Shape-locking ensures good fastening. The movement of the shape-locking
members into an open position may take place mechanically when the transfer
device moves toward the magazine, and the shape-locking members may
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move back into the locking position by means of a spring member, when the
transfer member is moved away from the magazine.
[0023] The idea of an embodiment is that the shape-locking mem-
bers between the drill bit holder and gripping member of the transfer device
have in the gripping member at least one spring locking device arranged to
settle in at least one locking groove or corresponding locking recess in the
drill
bit holder. Means to stop the flexing of the spring locking device away from
the
locking recess, that is, to stiffen the spring locking device, may be located
in
the gripping member.
Brief description of the figures
[0024] Some embodiments of the invention will be described in
more detail in the attached drawings, in which
Figure 1 is a schematic side view of a rock drilling rig, the drilling
unit of which is furnished with a retainer and a drill bit changer attached
thereto,
Figures 2a to 2c are schematic perspective views of drill bits, and
Figure 2b also illustrates gripping to the hole inside the drill bit,
Figure 3 is a schematic top view of the operation of a drill bit
changer,
Figure 4 is a schematic view of a magazine,
Figure 5 is a schematic, partly sectional detail of the magazine of
Figure 4,
Figure 6 is a schematic side view of a possible shape-locking be-
tween the gripping member of the transfer device and the drill bit holder,
Figure 7 is a schematic, partly sectional side view of a gripping
member of the transfer device,
Figures 8a and 8b are schematic top views of the locking principle
of the gripping member according to Figure 7, and
Figures 9a and 9b show schematic, sectional side views of yet an-
other arrangement for locking the gripping member to the drill bit holder by
means of an expanding machine element.
[0025] In the figures, some embodiments of the invention are shown
simplified for the sake of clarity. Similar parts are marked with the same
refer-
ence numbers in the figures.
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Detailed description of the invention
[0026] The rock drilling rig 1 shown in Figure 1 comprises a mov-
able carrier 2 on which one or more drilling booms 3 are arranged having a
drilling unit 4 at their outermost ends. The drilling unit 4 comprises a feed
beam
supporting a rock drilling machine 6 that may be moved by means of a feed
device 7 in the drilling direction A and reverse direction B. In the figure, a
dot-
ted line marks a drilling line, that is, drilling centre C. The rock drilling
machine
6 may comprise an impact device 8 for providing impact pulses on a tool 9
connected to the rock drilling machine 6. Further, the rock drilling machine 6
may comprise a rotating device 10 for turning the tool 9 about its
longitudinal
axis. During drilling, the tool 9 is in the drilling centre C and may comprise
a
drill rod 11 that has at its outermost end a replaceable drill bit 12.
Further, in
what is known as extension rod drilling, several drill rods 11 are connected
consecutively to drill long bores 13. When drilling rock, the bit buttons of
the
drill bit 12 or corresponding parts cutting the rock wear and may also be dam-
aged, which is why drill bits 12 are changed during drilling. Further,
different
special bits for various drilling situations and rock conditions may be used
to
improve rock drilling and drilling quality. The drill bit 12 is typically
connected to
the drill rod 11 with a threaded connection.
[0027] At the leading end of the feed beam 5, that is, in the outer-
most part of the feed beam 5 as seen in the drilling direction A, there is a
re-
tainer 14 that comprises jaws or corresponding holding members, with which a
replaceable drill bit 12 may be fastened stationary at least for as long as
the
threaded connection between the drill rod 11 and drill bit 12 is opened or
closed by rotating the drill rod by means of the rotating device 10 of the
rock
drilling machine 6. The retainer 14 may be positioned in such a manner that
the held tool 9 is in the drilling centre C. The structure of the retainer 14
may
be constructed in various ways.
[0028] On the leading edge portion of the feed beam 5, in connec-
tion with the retainer 14, a drill bit changer 15 is also arranged, and it com-
prises a magazine 16 in which a required number of drill bits, typically 5 to
10,
may be stored. The magazine 16 may be a rotating disc, in which spaces are
formed for supporting the drill bits 12 to be stored. Alternatively, the
magazine
16 may be a chain magazine or any other suitable construction with several
corresponding spaces. The drill bit changer 15 may further comprise one or
more stopping members 17 with which the drill bit 12 may be mechanically
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stopped at a predefined axial position in the drilling centre C. The stopping
member 17 may be a slide, for instance, which may be pushed from the front
side of the retainer 14 into the drilling centre C and against whose surface
on
the rock drilling machine 6 side the leading end of the drill bit 12 is pushed
be-
fore the drill bit 12 is fastened with the retainer 14 stationary for the
purpose of
change. Yet further, the drill bit changer 15 comprises one or more transfer
devices 18 with which the drill bits 12 may be transferred from the magazine
16 to the retainer 14 and vice versa.
[0029] Figures 2a to 2c show different drill bits 12. As seen from the
figures, the drill bits 12 are externally quite different. The drill bit 12 of
Figure
2a has a spiral groove on the outer circumference of the frame part 12a,
whereas in the drill bit 12 of Figure 2b, the frame part 12a is a smooth
cylinder.
Further, in Figure 2c, the frame part 12a is equipped with a grooved shoulder
20. Because the external appearances of different drill bits 12 may differ
quite
a lot from each other, it is difficult to handle the drill bits 12 at their
frame parts
12a. It is demanding to create a universal gripper or the like. On the other
hand, gripping the tip or working part 12b at the leading end of the drill bit
12
should be avoided, because it is the most critical part of the drill bit and
equipped with hard, but fragile drill buttons 21. However, the drill bits 12
may
be handled by means of a suitable projecting or pin-like separate drill bit
holder
22 that may be pushed into the hole 23 in the frame part 12a of the drill bit
ar-
ranged to normally receive the connecting part of the drill rod 11. Owing to
the
drill bit holder 22, the drill bits 12 may be handled in the magazine 16 and
dur-
ing transfers without the risk of damaging the working part 12b.
[0030] Figure 3 shows a drill bit changer 15 arranged to a retainer
14. The changer 15 may comprise a transfer device 18 that is a kind of ma-
nipulator. The transfer device 18 may comprise a first transfer device 18a and
a second transfer device 18b that are connected to each other by means of a
fastening piece 35. The first transfer device 18a is arranged to move the sec-
ond transfer device 18b and a gripping member 36 connected thereto linearly
in the transverse direction E so that the drill bit 12 may be transferred
between
the magazine 16 and the jaws 25 of the retainer 14. The second transfer de-
vice 18b is arranged to move the drill bit holder 22 in and out of the drill
bit hole
23. The drill bit holder 22 is an elongated piece whose first end may comprise
a gripping part 38 to which the gripping member 36 of the transfer device 18
may attach and by means of which the drill bit holder 22 is fastened to the
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magazine 16. Further, the drill bit holder 22 may comprise an arm 39 with two
or more support pieces 40a and 40b arranged thereto and dimensioned to
support themselves against connection threads 41 when inside the hole 23 of
the drill bit 12. Further, the rearmost first support piece 40a may comprise a
shoulder 46, flange or the like that may support itself against the rear
surface
of the drill bit 12 and support the drill bit 12 in the axial direction. When
the drill
bit holder 22 is pushed by means of the second transfer device 18b into the
hole 23, the first support piece 40a settles against the rear part of the
drill bit
12, whereas the second support piece 40b that is rigidly connected to the arm
39 may push even further toward the leading end of the drill bit 12. The
support
pieces 40a and 40b then settle at a distance from each other, whereby the
drill
bit 12 is firmly supported by the surfaces of the hole 23. The spaced apart
support pieces 40a, 40b ensure that the drill bit 12 remains straight. The bit
holder 22 may have adjusting members 45, such as adjusting screws, with
which the maximum distance between the support pieces 40a, 40b in the di-
rection H may be adjusted. At the same time, the adjusting member 45 affects
the distance between the gripping part 38 and first support piece 40a in the
direction H. Because the drill bit 12 is supported at its rear by means of a
shoulder 46, the adjustment of the drill bit holder 22 permits the setting of
the
leading ends of drill bits 12 of different lengths at the same point in the
maga-
zine 16. When the magazine is positioned at the retainer 14 in the axial direc-
tion and when the leading ends of the drill bits 12 are set level in the
magazine
16, transfers between the magazine 16 and retainer 14 may be done using a
simple crosswise linear movement E of the first transfer device 18a.
[0031] When the drill bit 12 is pressed between the jaws 25, the
second transfer device 18b is used to pull the drill bit holder 22 backward,
that
is, in the reverse direction B, whereby the support pieces 40a, 40b settle
against each other and emerge from the hole 23. Next, the drill bit holder 22
is
transferred by means of the first transfer device 18a away from the drilling
cen-
tre C, and the drill rod 11 is connected to the drill bit 12, after which the
stop-
ping member 17 and jaws 25 are opened. Normal drilling may then begin.
[0032] Figure 3 further shows that the drill rod 11 is transferred in
the drilling centre C in the reverse direction B for the time of the drill bit
12 re-
placement. The leading end of the drill rod 11 is equipped with a connection
part 43 with a connection thread 44 that may be connected to an internal con-
nection thread 41 of the drill bit 12 in the retainer 14 by feeding the drill
rod 11
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in the drilling direction A and at the same time turning the drill rod 11
about its
longitudinal axis by means of the rotating device 10 of the rock drilling
machine
6. When the drill bit 12 connected to the drill rod 11 is detached, the
stopping
member 17 is closed and the drill bit 12 is pushed against the stopping mem-
ber 17. This way, the drill bit 12 is always positioned correctly for the
transfer
device 18 and retainer 14.
[0033] Figure 4 also shows that the magazine 16 may comprise a
disc-like frame part 50 that may be turned relative to the rotation axis 29 to
se-
lect the required drill bit. The circumference of the frame part 50 of the
maga-
zine 16 has several spaces 30 into which a drill bit holder 22 like the one de-
scribed in Figures 2b and 3 may be detachably arranged. By turning the frame
part 50 in the direction G, each space 50 may be set one at a time into the
changing station 37, in which the drill bit holder and a possible drill bit in
it may
be removed from the magazine by using the transfer device or, alternatively, a
drill bit holder may be arranged into an empty space 30 by means of the trans-
fer device. The spaces 30 are elongated holes that open towards the outer
circumference of the frame part 50. A protective part 51 may surround the
outer circumference of the frame part 50 to prevent the exit of drill bit
holders
from the spaces 30 when not at the changing station 37.
[0034] Figure 5 shows a detail of the magazine 16 according to Fig-
ure 4. The gripping part 38 of the drill bit holder may be cylindrical and may
comprise a circumferential fastening groove 52, with which the gripping part
38
may fasten to the elongated space 30 in the frame part 50 of the magazine.
The figure also shows the protective part 51 that prevents the drill bit
holder
from sliding away from the space 30 in the direction of the radius of the disc-
like frame part.
[0035] Naturally, the gripping part 38 of the drill bit holder 22 may
also be constructed in some other manner, as may the spaces 30 in the maga-
zine and the transfer pin or corresponding gripping member 36 of the transfer
device.
[0036] If the magazine 16 is a chain magazine, a movable chain
forms its frame part that is equipped with several fastening spaces for receiv-
ing the drill bit holders 22. Correspondingly, the frame part of the magazine
may also be of a different shape and it may be moved linearly instead of a
turning movement.
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[0037] It should be noted that the support pieces 40a, 40b of the
drill bit holder 22 may comprise means for gripping the drill bit hole 23 so
that
the drill bit 12 will not detach from the holder 22 even though the feed beam
5
was directed downward. The support pieces 40a, 40b may comprise friction
pieces, such as retaining rings made of rubber or a corresponding elastic ma-
terial. Further, the drill bit holder 22 may have an expanding section that
may
expand under the effect of a pressure medium or mechanical movement and
press against the inner surfaces of the hole 23 of the drill bit 14.
[0038] Figure 6 shows in a very simplified manner an arrangement
for fastening the drill bit holder 22 to the gripping member 36 of the
transfer
device. The gripping member 36 may be equipped with spring locking mem-
bers 60 having locking nails or corresponding protrusions 61 that in their
lock-
ing position may be inside a locking groove or a corresponding locking recess
63 in a hole 62 belonging to the gripping part 38 of the drill bit holder 22.
This
forms a shape lock between each spring locking member 60 and locking re-
cess 63 to prevent the drill bit holder 22 from inadvertently detaching from
the
gripping member 36. The spring locking members 60 may be stiffened in their
locking position so that the locking protrusions 61 cannot move away from the
locking recess 63 in the manner shown by the dashed line in Figure 6. The
gripping member 36 may have means with which the locking protrusions 61
may, when desired, be released, whereby the drill bit holder 22 and gripping
member 36 may be detached from each other. Instead of the spring-like lock-
ing members 60, it is naturally also possible to use rigid locking members
that
shape-lock with the form surfaces in the hole 62. The relative movement of the
shape-locking members to open and close the shape lock may take place me-
chanically, for instance due to the movement of the transfer device, or
alterna-
tively it is possible to use a pressure medium-operated or electrically
operated
actuator to provide the necessary movement.
[0039] Figure 7 shows a gripping member 36 that comprises two
spring locking members 60 fastened to the frame 64. Further, the gripping
member has a centre pin 65 arranged rotatably relative to the frame 64. The
centre pin 65 is furnished with longitudinal grooves 66, whereby the centre
pin
65 may be turned about its longitudinal axis into a position where the grooves
66 are at the spring locking members 60. The spring locking members 60 may
then push into the grooves 66, which permits the spring locking members to
move away from the locking groove or the like of the drill bit holder. In
their
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locking position, the spring locking members 60 are against the outer surface
of the centre pin 65, whereby they cannot yield away from the locking groove
of the drill bit holder. In this embodiment, the spring locking members 60 are
thus stiffened in their locking position, whereby the shape lock between the
drill
bit holder and gripping member 36 is rigid. When the spring locking members
60 are at the grooves 66 and the gripping member 36 is pushed to the gripping
part of the drill bit holder, the spring locking members 60 may bend toward
the
grooves 66 and yield until they finally push into the locking groove of the
drill
bit holder.
[0040] Figure 8a illustrates in a very simplified manner a situation, in
which the grooves 66 and the spring locking members 60 are at different
points. When the transfer device moves the gripping member 36 in the direc-
tion R, a first mating surface 67 meets a second mating surface 68 in the
magazine 16, which provides a turning movement S of the centre pin 65. As a
result of this, the grooves 66 settle at the position of the spring locking
mem-
bers 60, as shown in Figure 8b. A spring member may act on the centre pin 65
to turn it back to its locking position after the gripping member 36 is moved
away from the magazine 16.
[0041] Figure 9a shows an arrangement, in which the gripping
member 36 is locked to the drill bit holder 22 by means of an expanding lock-
ing member 70, such as a rubber sleeve or the like. The drill bit holder 22
may
have a locking recess 63 or groove, to which the locking member 70 may push
sideways as shown in Figure 9b after the turning member 71 has been acted
on and the centre pin 72 has made the pressing sleeve 73 press the locking
member 70. Between the centre pin 72 and pressing sleeve 73, there may be
a high-pitch thread 74 that converts the turning movement of the centre pin 72
to a linear movement of the pressing sleeve 73. The turning member 71 may
be acted on in the same way as the first mating surface 67 is acted on in Fig-
ures 8a and 8b. Naturally, the turning of the centre pin 72 may also be pro-
vided with a suitable rotating device. The expanding locking member 70 may
also be a spring member, such as a spring plate which under pressure ex-
pands sideways and pushes into the locking recess 63.
[0042] It should be noted that the locking solution shown in Figures
8a to 9b may also be applied to situations where the gripping member 36 grips
the drill bit or some other drill component directly.
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[0043] In some cases, the features described in this application may
be used as such, regardless of other features. On the other hand, the features
described in this application may also be combined to provide various combi-
nations as necessary.
[0044] The drawings and the related description is only intended to
illustrate the idea of the invention. The invention may vary in detail within
the
scope of the claims.
