Note: Descriptions are shown in the official language in which they were submitted.
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METHOD FOR USING RETAINER, AND RETAINER
BACKGROUND OF THE INVENTION
[0001] The invention relates to a method for moving clamping arms
of a retainer belonging to an excavation apparatus in such a manner that
clamping jaws provided in the clamping arms move simultaneously towards
each other, clamping between them a drill rod, rock bolt or a similar
excavation
tool, which is located in the drilling centre of the rock drilling unit or
another
excavation apparatus. Mechanical synchronization is provided between the
clamping arms to render their movements interdependent.
[0002] The invention further relates to a retainer adaptable to a feed
beam of a rock drilling unit, bolting device or a similar excavation
apparatus.
The retainer comprises at least two clamping jaws that are moved by means of
one or more actuators. Between the clamping arms there is a synchronization
mechanism to render their movements interdependent.
[0003] The field of the invention is described in greater detail in the
preambles of the independent claims.
[0004] Rock drilling is performed using a rock drilling unit provided
with a rock drilling machine and a tool connected thereto to produce a drill
hole
into the material to be worked on. The tool may comprise a drill rod and a
drill
bit connected to the distal end thereof or, if long drill holes are to be
drilled, a
plurality of successive drill rods connected one after the other into an
extension
rod arrangement. When drilling is started, the drill rod needs to be centred
by
guiding it with the clamping jaws of the retainer in the drilling centre.
Moreover,
the retainer may be used for locking the drill rod or other drilling tools to
pre-
vent them from rotating for example when drill rods are attached to each
other,
to the drilling machine or the drill bit.
[0005] Publication US 4 438 984 discloses a retainer in which the
clamping arms of the retainer are interconnected by a rod transmitting the
forces from one arm to another. The disclosed structure occupies a lot of
space on the feed beam.
SUMMARY OF THE INVENTION
[0006] It is an object of the invention to provide a novel and im-
proved method for using a retainer, and a retainer.
[0007] The method of the invention is characterized by providing the
clamping arms with shape members in the portion between their pivot points
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and synchronizing with the shape members the movement between the first
clamping arm and the second clamping arm in both travel directions of the
clamping arms.
[0008] The retainer of the invention is characterized in that the syn-
chronizing means of the retainer are arranged on the portion between a first
and a second pivot joint; and that the synchronizing means comprise shape
members formed on the first and the second clamping arms and arranged to
transmit the synchronization movements between the clamping arms in both
travel directions thereof.
[0009] An idea of the invention is that the retainer comprises syn-
chronization means with which the movements of the clamping arms are made
mutually dependent. The synchronization means are separate from one or
more actuators acting on the clamping arms and transmit the movements of
the clamping arms in both travel directions thereof. The synchronization means
are implemented by shape members arranged to the clamping arms and lo-
cated on the portion between the pivot joints of the clamping arms.
[0010] An advantage of the invention is that since the synchroniza-
tion means are arranged on the portion between the pivot joints, they do not
add to the outer dimensions of the retainer in any way. A further advantage is
that by utilizing shape surfaces formed to the clamping arms, synchronization
may be implemented using a simple mechanical structure and a small number
of components. Due to this synchronization does not increase significantly the
weight of the retainer. Moreover, the retainer operates reliably.
[0011] According to an embodiment the shape members on the por-
tion between the pivot points are in constant contact with each other, and
thereby at all times ready to synchronize the movements of the clamping arms
in both travel directions.
[0012] According to an embodiment the synchronizing means com-
prise shape surfaces formed directly to the structure of the first and the
second
clamping arms, the surfaces being arranged against each other and transmit-
ting synchronization movements between the clamping arms through their con-
tact surfaces that set against each other.
[0013] According to an embodiment the first clamping arm and the
second clamping arm are provided with mutually compatible teeth arranged
against each other, movement between the clamping arms being transmitted
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by direct tooth contact. The teeth may be made directly to the structure of
the
clamping arms.
[0014] According to an embodiment the shape surfaces formed to
the first and the second clamping arms are in constant contact with each other
at least on some portion thereof.
[0015] According to an embodiment the synchronization means
comprise shape surfaces formed to the first and the second clamping arm on a
portion between the pivot joints. The shape surfaces are interconnected by a
connecting piece separate from the clamping arms and arranged against the
shape surfaces. However, the connecting piece is not attached to the clamping
arms and the shape surfaces provided in them. During synchronization,
movement may take place between the form surfaces and the connecting
piece.
[0016] According to an embodiment the first clamping arm com-
prises at least two first connecting cams arranged at an axial distance from
one another, when the retainer is observed in the direction of the centre. Cor-
respondingly, the second clamping arm comprises at least two second con-
necting cams on a portion between pivot joints, the cams being arranged at an
axial distance from one another. The first connecting cams and the second
connecting cams are interleaved on the portion between the pivot joints. Fur-
ther, the first and the second connecting cams are provided with connecting
slots that open towards each other and are arranged to coincide when ob-
served in the direction of the centre, the connecting slots being arranged to
form a connecting channel when observed in the direction of the centre. This
connecting channel is provided with a connecting pin that serves as a trans-
mission member between the interleaved connecting cams. The connecting
pin moves in a vertical direction when the clamping arms are moved. The ver-
tical movement of the connecting pin is allowed through a longitudinal hole or
the like provided in the body of the retainer. The connecting pin is a
separate
piece not attached to the clamping arms.
[0017] According to an embodiment the first clamping arm is pro-
vided with an immobile connecting pin, whose outer surface serves as a first
shape surface. The second clamping arm comprises a longitudinal connecting
opening that serves as a second shape surface. The connecting pin is ar-
ranged through the connecting opening, their shape surfaces transmitting syn-
chronization movements between the clamping arms.
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[0018] According to an embodiment the retainer comprises only a
single actuator arranged between the clamping arms and connected to act si-
multaneously on both clamping arms.
[0019] According to an embodiment the retainer comprises only a
single actuator arranged to act on the first clamping arm only. In that case
movement to the second clamping arm is transmitted by the synchronization
means.
[0020] According to an embodiment the retainer comprises at least
two actuators, at least a first actuator being connected to act on the first
clamp-
ing arm only and at least one second actuator being arranged to act on the
second clamping arm only.
[0021] According to an embodiment the actuator is a hydraulic cyl-
inder connected to a clamping arm by a pivot.
[0022] According to an embodiment the actuator is arranged to di-
rect the forces needed for moving the clamping arms directly to the clamping
arms. This is advantageous for the durability of the construction.
[0023] According to an embodiment the actuator is connected to the
clamping arm by a pivot. The pivoting makes the construction durable and,
moreover, it may be used to reduce friction.
[0024] According to an embodiment the actuator is a pressure me-
dium cylinder arranged transversally in relation to the longitudinal axis of
the
clamping arms. The linear travel direction of the actuator is thus arranged to
substantially correspond to the travel directions of the clamping jaws.
[0025] According to an embodiment the actuator is placed outside
the portion between the pivot points of the clamping arms. Hence a fixing
point,
where the actuator is connected to the clamping arm, may be located at a
greater distance from a pivot point of the clamping arm, thus allowing a
greater
torque arm to be achieved and thereby the clamping force produced by the
actuator to be increased.
[0026] According to an embodiment the clamping jaws comprise a
slot of a substantially V-shaped cross-section on their surfaces facing each
other, thus allowing the clamping jaws to centre a drill rod or the like
pressed
between them. Due to the shape of the jaws also drill rods and the like with
differing diameters may be centred.
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[0027] According to an embodiment the clamping jaws are arranged
to move at the same travel speed, for the same distance and symmetrically in
relation to each other.
BRIEF DISCLOSURE OF THE FIGURES
[0028] Some embodiments of the invention will be described in
greater detail with reference to the accompanying drawings, in which
Figure 1 is a schematic side view of a rock drilling rig provided with
booms and drilling units arranged thereto and a second excavation apparatus;
Figure 2 is a schematic perspective view of a drilling unit;
Figure 3 is a schematic view of a retainer of the invention, seen from
the direction of the front end of the feed beam;
Figure 4 is a schematic perspective view of the retainer of Figure 3
without a body plate;
Figure 5 is a schematic cross-sectional view along line E - E of the
retainer of Figure 2;
Figure 6 is a schematic cross-sectional view along line D - D of the
retainer of Figure 2;
Figure 7 is a schematic cross-sectional view along line F - F of the
retainer of Figure 2;
Figure 8 is a schematic view of a retainer of the invention seen from
the direction of the front end of the feed beam, each clamping arm of the re-
tainer being acted on by a separate actuator;
Figure 9 is a schematic view of a retainer of the invention seen from
the direction of the front end of the feed beam, only one clamping arm of the
retainer being acted on by an actuator;
Figure 10 is a schematic view of a second alternative solution for
synchronizing the turning movement between the clamping arms by toothed
peripheries;
Figure 11 is a schematic view of a third alternative solution for syn-
chronizing the turning movement between the clamping arms by transverse
longitudinal openings provided in the clamping arms and a connecting pin ar-
ranged through the openings;
Figure 12 is a further schematic view of a fourth alternative solution
for synchronizing the turning movement between the clamping arms by a fixed
connecting pin and a longitudinal opening.
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[0029] For the sake of clarity, some embodiments shown in the fig-
ures have been simplified. Like parts are referred to with like reference num-
bering throughout the figures.
DETAILED DESCRIPTION OF SOME EMBODIMENTS OF THE INVENTION
[0030] Figure 1 shows an excavation apparatus 1 comprising a
movable carrier 2 provided with one or more booms 3. A first boom 3a is a
drill-
ing boom provided with a rock drilling unit 4. The drilling unit 4 comprises a
rock drilling machine 5 that is movable on a feed beam 6 by a feed device 7.
The rock drilling machine 5 may be provided with a tool 8 coupled thereto and
comprising a plurality of successive drill rods 9, which are attached to each
other by connecting means, such as a threaded joint. Further, at the distal
end
of the drill rod there is a drill bit 10 having drill buttons for making a
drilling hole
12 into rock 11. The rock drilling machine 5 may comprise an impact device
used for delivering impact pulses to the tool 8 that transmits them to the
drill bit
and further to the rock 11 to be broken. The rock drilling machine 5 may
also comprise a rotating device allowing the tool 8 to be rotated about its
longi-
tudinal axis during drilling. The drilling unit 4 may also be provided with a
rod
magazine 13 supported on the feed beam 6. The rod magazine 13 may be
used for storing extension rods 9 and other drilling tools needed in long hole
drilling. The rod magazine 13 is provided with transfer means for transferring
drilling tools between the rod magazine 13 and the drilling axis, i.e. the
centre
K. The distal end portion of the feed beam 6 is provided with retainer 14 that
has jaws for clamping the tool 9 and centring it in the drilling centre K. The
jaws may take hold of the shaft or the connecting sleeve of the drill rod 9,
thus
allowing the rod to be held in place when the joints are screwed or unscrewed.
Further, it is possible to grab the drill bit 10 with the retainer and to hold
it in
place when the drill bit 10 is to be changed. In addition to the rod magazine
13
the feed beam 6 may be provided with a drill bit magazine.
[0031] A second boom 3b of the excavation apparatus 1 of Figure 1
is provided with another excavation device 15 for handling excavation tools
16,
such as rock bolts, injection tubes and the like. Also these may need to be
held
by the jaws or the tool may need to be centred to the centre K of the appara-
tus. In such cases also these excavation devices 15 may be provided with the
retainer 14 of the invention.
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[0032] Figure 2 shows a rock drilling unit 4 in which the feed beam 6
is provided with a rod magazine 13 in which drill rods 9 needed in drilling
are.
The distal end of the feed beam 6 is provided with a retainer 14, the possible
structural alternatives of which are shown in greater detail in Figures 3 to
12.
[0033] The retainer 14 of Figure 3 comprises a body 17 allowing it
to be attached to the feed beam. The retainer 14 also comprises a first clamp-
ing arm 18a connected by a first pivot joint 19a to the body 17 and a second
clamping arm 18b connected by a second pivot joint 19b to the body 17. The
clamping arms 18 may be moved in relation to the pivot joints 19 by an actua-
tor 20 located between them, whereby clamping jaws 21 a, 21b at the distal
ends of the clamping arms 18 move either towards or away from each other,
depending naturally on the direction of movement of the actuator 20. The ac-
tuator 20 may be a pressure medium cylinder, such as a hydraulic cylinder,
that may be connected to the clamping arm 18 by joints 22. The actuator 20
then transmits the forces directly to the clamping arms. The actuator 20 is
placed outside the portion between the pivot joints 19a and 19b. The point of
connection of the actuator 20, i.e. the joint 22, is located at a distance
from the
pivot joint 19a, 19b, whereby a torque arm is generated between the joints 19
and 22. The clamping jaws 21 may comprise centring surfaces on their sur-
faces facing each other and thus, when they move towards each other, they
may centre the drill rod 9 or other tool between them precisely into the
centre
K. The centring surfaces 23 may have a substantially V-shaped cross-section
and they naturally open towards the centre K. Of course other inclined or coni-
cal centring surfaces 23 may also be used in the clamping jaws 21. The clamp-
ing arms 18 are made to move interdependently by synchronization means 24
provided on the portion between the pivot joints 19. In other words, the syn-
chronization means 24 are separate from the actuator 20. Figure 3 shows a
connecting pin 25 which is parallel with the centre K and may belong to the
synchronization means 24. As is seen, the body 17 is provided with a longitu-
dinal opening 26 in the vertical direction, the opening allowing the
connecting
pin 25 to move in vertical direction V, when the clamping arms 18 are moved.
[0034] In Figure 4 part of the body 17 has been removed for better
visibility of the synchronization means 24. On the portion between the pivot
joints 19 the first clamping arm 18a may comprise two or more first connecting
cams 27, which are at an axial distance from one another when the retainer 14
is observed in the direction of the centre K. Correspondingly, the second
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clamping arm 18b may comprise two or more second connecting cams 28. The
connecting cams 27, 28 are interleaved on the portion between the pivot joints
19, as shown in Figure 4. Further, the connecting cams 27, 28 are provided
with connecting slots 29 that may open towards each other and are arranged
to coincide in the axial direction so that together they form a kind of a
connect-
ing channel 30. This axial connecting channel 30 is provided with a connecting
pin 25 that may serve as a transmission member between the connecting
cams 27, 28. When the clamping arms 18 are moved, movement takes place
in the contact surfaces of the connecting slots 29 and the connecting pin 25,
and in addition, the connecting pin 25 moves linearly in a vertical direction,
i.e.
it moves either towards the centre K or away from it. In this application the
shape surfaces belonging to the synchronization means 24 are implemented
by surfaces of the connecting channel 30, which are in contact with the con-
necting pin 25.
[0035] The cross-section of Figure 5 further clearly shows the for-
mation of a connecting channel 30 between the connecting cams 27, 28. For
vertical movement of the connecting pin 25 the body 17 is provided with longi-
tudinal openings 26a, 26b. The cross-sectional Figures 6 and 7 further clarify
the construction of this embodiment. Unlike in Figures 4 to 7, it may be possi-
ble to provide connecting slots 29 with a closed shape. The cross-section of
the connecting pin 25 is preferably circular.
[0036] In the embodiment of Figure 8 a first actuator 20a transmits
force to a first clamping arm 18a only and a second actuator 20b transmits
force to a second clamping arm 18b only. The synchronization means 24 en-
sure the simultaneity of the movement of the clamping arms 18.
[0037] In the embodiment of Figure 9 the force from the actuator 20
is transmitted only to the first clamping arm 18a and the synchronization
means 24 transmit the movement to the second clamping arm 18b.
[0038] Figure 10 shows a strongly simplified embodiment of syn-
chronization means 24 including teeth 31a, 31b formed to the clamping arms
18. The teeth are formed to the curved transmission surfaces of the pivot
joints
19. In this application the synchronization movements are transmitted directly
through contact with the teeth, therefore no connecting pins or a similar con-
necting members are needed. The teeth 31 serve as the necessary shape
members between the clamping arms 18.
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[0039] Figure 11 shows a strongly simplified embodiment of syn-
chronization means 24 provided with a first longitudinal connecting opening
32a in the first clamping arm 18a and a second longitudinal connecting open-
ing 32b in the second clamping arm 18b. At least on the portions of the con-
necting openings 32 the clamping arms 18 are interleaved in relation to each
other. The clamping arms 18 may be provided with connecting cams 27, 28 or
corresponding projecting portions on these interleaved portions. The connect-
ing openings 32 are arranged transversally with respect to each other,
whereby they together define a connecting channel 30 with a connecting pin
25 arranged therein. The connecting pin 25 is not attached to the connecting
openings 32 but it is allowed to move in the longitudinal direction of the con-
necting openings 32 and, at the same time, also in a vertical direction with
re-
spect to the centre K, when the clamping arms 18 are moved by applying a
turning force to the force transmission points 22.
[0040] Figure 12 shows yet another strongly simplified embodiment
of the synchronization means 24 having a longitudinal connecting opening 32
formed to the first clamping arm 18a and an immovably fixed connecting pin 25
provided on the second clamping arm 18b.The clamping arms 18 are inter-
leaved with respect to each other on the portion of the connecting opening 32
and the connecting pin 25. The clamping arms 18 may be provided with con-
necting cams 27, 28 or similar protruding portions on these interleaved por-
tions. When the actuator 20 turns the clamping arms 18 with respect to their
pivots 19, the connecting pin 25 follows a curved path and, at the same time,
its position in the connecting opening 32 changes. Further, it is possible
that
the connecting cam 27 comprises a slot-like connecting opening 32 that opens
towards the second clamping arm 18b. In this application the outer surface of
the connecting pin 25 and the edges of the connecting opening 32 serve as
shape surfaces transmitting the synchronization movements.
[0041] In the embodiments of Figures 3 to 7, 11 and 12 the connect-
ing pin 25 is arranged between the interleaved portions and is to be subjected
substantially to shearing forces only. In that case the connecting pin 25 may
be
relatively thin, yet it is able to transmit even strong forces between the
clamp-
ing arms 18. In the embodiments of Figures 3 to 7 and 11 there is a separate
connecting pin 25 that is easy to detach and replace.
[0042] It should be noted that the opening movement of the clamp-
ing jaws 21 of the retainer 14 may be arranged to be sufficiently large to
allow
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it to be used for clamping both the shaft of the drill rod 9 and the
connecting
sleeve between successive drill rods 9. Also the drill bit 10 or any other
tool
used in excavation may be gripped with it.
[0043] When in this application reference is made to a vertical direc-
tion or a vertical movement, this means a vertical movement in relation to the
basic position of the feed beam and the retainer, the feed beam being horizon-
tal in that position. When the boom and the feed beam are turned during op-
eration, this naturally changes also the position of the retainer. Although in
ab-
solute terms the direction changes, the retainer nevertheless maintains its
rela-
tive position with respect to the feed beam.
[0044] In some cases the characteristics presented in this applica-
tion may be used as such, independently of other features. However, the char-
acteristics presented in this application may also be combined, when neces-
sary, to provide different combinations.
[0045] The drawings and the related specification are only meant to
illustrate the inventive idea. The details of the invention may vary within
the
scope of the claims.
