Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
WO 2023/048606
PCT/SE2021/050933
1
A HYDRAULIC ARRANGEMENT FOR A ROCK DRILLING MACHINE
TECHNICAL FIELD
The present disclosure relates to a hydraulic arrangement for a rock drilling
machine on a
drill rig and a drill rig comprising such a hydraulic arrangement.
BACKGROUND
In currently available drill rig configurations, one or more hydraulic rock
drilling machines
are arranged on feeder arrangements at outer ends of respective one or more
booms that
extend from the drill rig. Hoses to provide the feeder arrangement and/or
hydraulic rock
drilling machine with hydraulic fluid are arranged in reels or other types of
hose suspension
arrangements that offer flexibility, both for the movement of the hydraulic
rock drilling
machine with respect to the feeder arrangement, but also for the positioning
of the feeder
arrangement with respect to the boom. The hydraulic rock drilling machine
itself typically
uses hydraulic pressure for several different function of the rock drilling
machine, such as
for driving a percussion unit, a rotation unit and a damper unit.
However, the hose suspension arrangements for providing hydraulic pressure are
often
both bulky and exposed to harsh conditions. In many cases the hoses may get
tangled up,
e.g., against a rock surface, resulting in hose ruptures. This is particularly
troublesome
when it happens to a hydraulic hose that supports an essential function of the
feeder
arrangement or the rock drilling machine. In those instances, a rupture of
hydraulic hose
will most likely result in an operational stop.
A drill rig often comprises at least two separate feeders extending from
separate booms,
each feeder carrying a hydraulic rock drilling machine and the associated
hydraulic hose
suspension arrangements. A common problem is that these hydraulic hose
suspension
arrangements may hinder each other, which may further aggravate the above-
mentioned
operational problems or hose ruptures and result in lengthy downtimes of the
drill rig.
Recent service evaluations indicate that 80% of the downtime of drill rig is
due to problems
related to the booms' feeder arrangements. Furthermore, 85% of the boom/feeder
related
CA 03227348 2024- 1-29
WO 2023/048606
PCT/SE2021/050933
2
problems occur due to damages on hydraulic hoses, including external damages
and
ruptures thereof.
Consequently, there is a need for a solution that reduces problems due to hose
entanglement or leaks in the conduits providing the rock drilling machine with
hydraulics.
SUMMARY
A primary object of the present disclosure is to achieve an in at least some
aspect
improved hydraulic arrangement for a rock drilling machine. In particular, it
is an object to
achieve such a hydraulic arrangement which reduces the risk for hose
entanglement and
hose ruptures occurring during rock drilling operations.
According to a first aspect of the disclosure, at least the primary object is
achieved by a
hydraulic arrangement according to claim 1. The hydraulic arrangement is
intended for a
rock drilling machine on a drill rig, wherein the rock drilling machine is
slidably mounted on
a feed beam of the drill rig so as to be movable between a first end and an
opposite
second end of the feed beam by means of the hydraulic arrangement. The
hydraulic
arrangement comprises:
- a first hydraulic conduit and a second hydraulic conduit, the first and
second
hydraulic conduits being configured so that pressurizing one of the first and
second
hydraulic conduits presses the rock drilling machine in a direction toward one
of the
first and second ends of the feed beam, respectively,
- a percussion unit input port for providing pressurized hydraulic fluid to
drive a
percussion unit of the rock drilling machine, and a percussion unit return
port for
returning hydraulic fluid from the percussion unit,
- a first valve arrangement in the form of a directional valve arrangement
arranged to
fluidly connect the first and second hydraulic conduits with the percussion
unit input
and return ports, the first valve arrangement being configured to:
when a pressure in the first hydraulic conduit exceeds a predetermined first
threshold, assume a first state in which it fluidly connects the first
hydraulic
conduit to the percussion unit input port, and in which it fluidly connects
the
percussion unit return port to the second hydraulic conduit,
CA 03227348 2024- 1-29
WO 2023/048606
PCT/SE2021/050933
3
o when a pressure in the second hydraulic conduit exceeds a predetermined
second threshold, assume a second state in which it fluidly connects the
second hydraulic conduit to the percussion unit input port, and in which it
fluidly connects the percussion unit return port to the first hydraulic
conduit,
o when the pressures in the first and the second hydraulic conduits are
both
below the first and the second thresholds, respectively, assume a closed
state in which it fluidly disconnects the first and second hydraulic conduits
from the percussion unit input and return ports.
By providing a directional valve arrangement for fluidly connecting the first
and second
hydraulic conduits to the percussion unit ports according to the present
disclosure, it is
possible to use hydraulic pressure from the same pressure source to drive the
percussion
unit and for moving the drilling machine in both directions along the feed
beam. Since the
valve arrangement is directional, hydraulic pressure can be provided to the
percussion
unit regardless of in which direction the drilling machine is being moved
along the feed
beam. The return port of the percussion unit is automatically connected to
that one of the
first and second hydraulic conduits with the lowest pressure, i.e. the conduit
which is
currently fluidly connected to a tank arrangement. The hydraulic arrangement
according to
the present disclosure thus makes it possible to provide hydraulic pressure
for driving the
percussion unit without providing dedicated hydraulic hoses, separate from any
hydraulic
circuits of the feeder arrangement. Vibrations arising during drilling may
thereby be
significantly reduced.
When the first valve arrangement is in the closed state, the percussion unit
is not
pressurized at all, and any hydraulic pressure below the first and second
thresholds may
thus be used solely for moving the rock drilling machine along the feed beam.
In the first
state of the first valve arrangement, the percussion unit input port is
pressurized by the
first hydraulic conduit and the rock drilling machine moves toward the first
end of the feed
beam. In the second state of the first valve arrangement, the percussion unit
input port is
pressurized by the second hydraulic conduit and the rock drilling machine
moves toward
the second end of the feed beam.
The hydraulic arrangement according to the invention may be used with
telescopic feeder
arrangements, comprising an extendable feed beam, or with non-telescopic
feeder
arrangements.
CA 03227348 2024- 1-29
WO 2023/048606
PCT/SE2021/050933
4
Optionally, the first valve arrangement is a pilot-controlled directional
valve arrangement.
By providing a pilot-controlled valve arrangement, i.e. a valve arrangement
comprising
one or two pilot conduit(s) for controlling the state, it is not necessary to
provide any
electronic controls for controlling the state of the first valve arrangement,
such as any
electronic controls on the rock drilling machine. Instead, the state of the
first valve
arrangement may be automatically actuated by the pressures in the first and
second
hydraulic conduits. This reduces a complexity of the hydraulic arrangement.
The pilot
conduits may be internal bores, or external conduits such as hoses.
Optionally, the first valve arrangement comprises a valve body having an
internal first pilot
conduit controlling movement of the valve body to the first state, and an
internal second
pilot conduit controlling movement of the valve body to the second state. By
providing the
pilot conduits internally in the valve arrangement, no additional hoses are
needed for
providing a pilot pressure actuating the valve. The internal pilot conduits
are typically in
the form of bores. First and second spring members may advantageously be
provided,
wherein the internal first pilot conduit controls movement of the valve body
to the first
state against a first spring force of the first spring member, and the
internal second pilot
conduit controls movement of the valve body to the second state against a
second spring
force of the second spring member. The first and second spring members may be
selected as identical spring members, or as spring members having different
spring
forces. The spring members should be selected to obtain desired pressure
thresholds for
moving the valve body to the different states.
Optionally, the first valve arrangement is arranged in the rock drilling
machine, or in a
slidable carrier on which the rock drilling machine is mounted.
Optionally, the hydraulic arrangement further comprises a damper input port
for providing
pressurized hydraulic fluid to drive a damper unit of the rock drilling
machine. The
hydraulic arrangement may further comprise a damper return port, wherein the
damper
return port may be fluidly connected to the percussion unit return port so
that the return
flow from both of the damper and the percussion unit use the same conduit. The
damper
unit ensures rock contact during drilling. It is to be noted that the damper
input port may
be fluidly connected to the percussion unit input port, or alternatively to a
rotation unit port
CA 03227348 2024- 1-29
WO 2023/048606
PCT/SE2021/050933
of the hydraulic arrangement, configured for driving a rotation unit, i.e. a
hydraulic motor
of the rock drilling machine.
Optionally, the hydraulic arrangement comprises a sequential valve arrangement
5 configured to first supply pressurized hydraulic fluid to the damper input
port, and only
thereafter supply pressurized hydraulic fluid to drive the percussion unit.
This may be
realized by providing a sequential valve arrangement configured to open only
when a
pressure on a pressure side of the sequential valve arrangement exceeds a
third
predetermined threshold, the damper input port being provided on the pressure
side of the
sequential valve arrangement. By means of the sequential valve arrangement,
rock
contact during the entire drilling operation may be ensured, since the damper
input port is
pressurized prior to the percussion unit.
Optionally, the damper input port is fluidly connected to the percussion unit
input port
between the first valve arrangement and the percussion unit.
Optionally, the sequential valve arrangement is integrated with the first
valve
arrangement. For example, a damper input port may be provided on each side of
the
percussion unit input port, wherein a valve body of the first valve
arrangement is
configured to move to open the damper input port on the pressure side before
it opens the
percussion unit input port. This reduces the need of an additional separate
sequential
valve arrangement.
Optionally, at least the first valve arrangement, the first and second
hydraulic conduits and
the percussion unit input and return ports form part of a first hydraulic
circuit, the first
hydraulic circuit further comprising a second valve arrangement in the form of
a
controllable directional valve arrangement, wherein the second valve
arrangement is
configured to selectively fluidly connect one of the first and second
hydraulic conduits to a
first hydraulic pressure source, and the other one of the first and second
hydraulic
conduits to a tank arrangement. The second valve arrangement is herein
configured to be
actively controlled by a user, for example via an electronic control unit, or
alternatively by
active pressure control or mechanical control. By actively controlling the
second valve
arrangement to pressurize either the first or the second hydraulic conduit,
the first valve
arrangement may be indirectly controlled. The first hydraulic circuit may
typically be
controlled to provide a predetermined hydraulic pressure for driving the
percussion unit.
The damper unit input port and return port may also form part of the first
hydraulic circuit.
CA 03227348 2024- 1-29
WO 2023/048606
PCT/SE2021/050933
6
Optionally, the hydraulic arrangement further comprises a second hydraulic
circuit, the
second hydraulic circuit being configured to provide a flow of hydraulic fluid
to drive a
rotation unit of the rock drilling machine. The second hydraulic circuit may
typically be
controlled to provide a predetermined hydraulic fluid flow instead of a
predetermined
hydraulic pressure. Optionally, the damper unit input port and return port may
form part of
the second hydraulic circuit instead of the first hydraulic circuit. Herein,
the rock drilling
machine comprises a rotation unit in the form of a hydraulic motor. The
rotation unit is
additional to the percussion unit, and if applicable the damper unit. Thus,
the rock drilling
machine may comprise a percussion unit, a rotation unit and a damper unit
configured to
be driven simultaneously in a rock drilling operation.
Optionally, the second hydraulic circuit comprises:
- a first rotation unit port, a second rotation unit port, and a third
valve arrangement in
the form of a controllable directional valve arrangement configured to
selectively
connect the first rotation unit port to one of a hydraulic flow source and the
tank
arrangement,
- third and fourth hydraulic conduits configured so that pressurizing one
of the third
and fourth hydraulic conduits presses the rock drilling machine in a direction
toward
one of the first and second ends of the feed beam, respectively,
- a fourth valve arrangement arranged to fluidly connect either one of the
third and
the fourth hydraulic conduits to the second rotation unit port in dependence
on a
pressure in the third and fourth hydraulic conduits, respectively.
The fourth valve arrangement allows for fluid connection to provide a flow of
hydraulic
fluid to or from the rotation unit via one of the third or fourth hydraulic
conduits, depending
on the relative pressures. The fourth valve arrangement may be arranged to
open the one
of the third and the fourth hydraulic conduits in which the pressure is lower,
and to close
the one of the third and the fourth hydraulic conduits in which the pressure
is higher. The
fourth valve may advantageously be a pilot-controlled valve. Similarly to the
first hydraulic
circuit, the fourth valve arrangement reduces the need for separate hoses for
hydraulic
fluid to the rotation unit.
By means of the third valve arrangement, a rotational direction and speed of
the rotation
unit can be controlled, as well as a feeding direction for moving the drilling
machine along
the feed beam. Thus, the drilling machine will move along the feed beam in
dependence
CA 03227348 2024- 1-29
WO 2023/048606
PCT/SE2021/050933
7
on the relative pressures as controlled by both of the second and third valve
arrangements. Since both the second and third valve arrangements can be used
to
control the feeding direction and speed, the hydraulic arrangement according
to this
embodiment can be used to control the movement of the drilling machine in a
number of
different operations, such as drilling, threading and unthreading with and
without
percussion, etc.
Optionally, the third valve arrangement is configured to selectively fluidly
connect one of
the third and fourth hydraulic conduits to a second hydraulic pressure source,
and the
other one of the third and fourth hydraulic conduits to the tank arrangement.
The second
hydraulic pressure source may be set to provide a hydraulic pressure as needed
for
controlling movement of the rock drilling machine along the feed beam as
discussed
above.
Optionally, the third valve arrangement comprises a first directional valve
unit movable
between three valve states, and a second directional valve unit movable
between at least
two valve states, the first and second directional valve units being
individually controllable.
This enables an individualized control of direction of rotation of the
rotation unit and
feeding direction of the drilling machine. The first directional valve unit
may be used for
controlling a feeding direction for movement of the drilling machine, and the
second
directional valve unit may be used for controlling a direction of rotation of
the rotation unit.
Optionally, the third and fourth hydraulic conduits are only fluidly
connectable to the tank
arrangement and to the hydraulic flow source via a combination of the first
and second
directional valve units.
Optionally, the third and fourth hydraulic conduits are fluidly connectable to
the second
hydraulic pressure source via the first directional valve unit only, and the
first rotation unit
port is fluidly connectable to either one of the hydraulic flow source and the
tank
arrangement via the second directional valve unit only.
According to a second aspect of the disclosure, a drill rig is provided_ The
drill rig
comprises a rock drilling machine, a feed beam and a hydraulic arrangement
according to
the first aspect. It further comprises at least one hydraulic pressure source,
a tank
arrangement, and a boom on which the feed beam is mounted and via which boom
the
CA 03227348 2024- 1-29
WO 2023/048606
PCT/SE2021/050933
8
hydraulic arrangement is fluidly connectable to the at least one hydraulic
pressure source
and to the tank arrangement.
Further advantages and advantageous features of the disclosure are disclosed
in the
following description and in the dependent claims.
BRIEF DESCRIPTION OF THE DRAWINGS
With reference to the appended drawings, below follows a more detailed
description of
embodiments of the disclosure cited as examples.
In the drawings:
Fig. 1 is a schematic view of a drill rig with three booms for respective
rock drilling
machines;
Fig. 2 is a schematic view of a drilling machine in a first position,
Fig. 3 is a schematic view of the drilling machine in a second position,
20 Fig. 4 is a schematic view of the drilling machine in a third position,
Fig. 5 is a schematic overview of a hydraulic arrangement according to an
embodiment of the disclosure,
25 Fig. 6 is a cross-sectional view of a valve within the hydraulic
arrangement,
Fig. 7 is a cross-sectional view of the valve according to another
embodiment, and
Fig. 8 is a cross-sectional view of another valve within the hydraulic
arrangement.
The drawings show diagrammatic, exemplifying embodiments of the present
disclosure and
are thus not necessarily drawn to scale. It shall be understood that the
embodiments shown
and described are exemplifying and that the disclosure is not limited to these
embodiments.
It shall also be noted that some details in the drawings may be exaggerated in
order to
CA 03227348 2024- 1-29
WO 2023/048606
PCT/SE2021/050933
9
better describe and illustrate the disclosure. Like reference characters refer
to like elements
throughout the description, unless expressed otherwise.
DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS OF THE DISCLOSURE
Fig. 1 schematically illustrates a drill rig 1 for rock drilling. The drill
rig 1 comprises three
booms 8A-8C equipped with individual rock drilling machines 3A-3C. The rock
drilling
machines 3A-3C are arranged on respective feed beams 2A-2C. In Fig. 1 it is
illustrated
how the three rock drilling machines 3A-3C operate by drilling individual
drill strings 19A-
19C into a rock face 100. As the rock drilling machines 3A-3C may advance
their way into
the rock face 100 they advance from a rear first end 21A-21C to a front second
end 22A-
22C of the feed beams 2A-20.
The drill rig 1 comprises a hydraulic pressure source PS and a tank
arrangement T. The
drill rig 1 may include more than one pressure source, wherein at least one
hydraulic
pressure source is a hydraulic pump adapted to provide a hydraulic pressure to
drive a
percussion unit of the rock drilling machine 3. The drill rig 1 may further
comprise a
hydraulic flow source in the form of a hydraulic pump adapted to provide a
hydraulic flow
to drive a rotation unit of the rock drilling machine 3. The hydraulic
pressure source(s),
and if applicable the hydraulic flow source, is/are arranged to feed different
consumers of
the rock drilling machines 3A-3C. Such consumers typically include at least a
percussion
unit, a damper unit, and a rotation unit. Further, the hydraulic sources are
arranged to
provide hydraulic fluid to hydraulic motors such as hydraulic cylinders
arranged to
advance the rock drilling machines 3A-30 along the corresponding feed beams 2A-
20.
The conduits for the hydraulic fluid are conventionally arranged along or
within the boom
8A-8C.
Fig. 2-4 show the rock drilling machine 3 in three different positions along
the feed beam
2. The rock drilling machine 3 is mounted on a slidable carrier 35. Interior
components of
the feed beam 2 are herein exposed. It will be obvious to the skilled person
that a
longitudinally extending beam structure or cover surrounding the interior
components
exposed in fig. 2-4 may be provided.
CA 03227348 2024- 1-29
WO 2023/048606
PCT/SE2021/050933
The first beam 2 extends between a first end 21 and an opposite second end 22.
The rock
drilling machine 3 is arranged to operate in an axial direction Al between the
first end 21
and the second end 22. Two first pipe connections 25 (only one marked) of the
feed beam
2 extend between the first end 21 and the second end 22. A rock drilling
machine
5 connector 26 is slidably arranged with respect to each first pipe connection
25 and with
respect to an intermediate pipe connection 28, in turn slidable with respect
to the first pipe
connection 25. The rock drilling machine connector 26 may be comprised in the
carrier 35
or connected to the carrier 35. The first pipe connection 25 is fluidly
connectable to the
pressure source(s) on the drill rig 1 via a connection provided in the first
end 21. The first
10 pipe connection 25 together with the rock drilling machine connector 26 and
the
intermediate pipe connection 28 connect the rock drilling machine 3 to the
pressure
source(s) and tank arrangement T on the drill rig 1 to provide pressurised
hydraulic fluid to
drive hydraulic consumers of the hydraulic rock drilling machine 3.
Pressurized hydraulic fluid may with the illustrated feed beam 2 be provided
to the rock
drilling machine 3 via internal conduits, e.g., via rigid pipes, inside the
feed beam 2,
whereby the risk of damages on the conduits caused by external factors is
minimized.
In fig. 2 the rock drilling machine 3 is positioned in a most retracted
position at the first
end 21 of the feed beam 2. In fig. 3, the rock drilling machine 3 is
positioned in an
intermediate position and in fig. 4 the rock drilling machine 3 is positioned
in a most
forward position at the second end 22 of the feed beam 2. A drill support 27
is arranged at
the second end 22 to support a drill string 19 that extends from the rock
drilling machine 3
during operation.
A hydraulic arrangement for a rock drilling machine 3 according to an
embodiment of the
present disclosure is schematically illustrated in fig. 5. The rock drilling
machine 3 is
slidably mounted on the feed beam 2 of the drill rig 1 so as to be movable
between the
first end 21 and the opposite second end 22 of the feed beam 2 by means of the
hydraulic
arrangement, as illustrated in fig. 2-4. The hydraulic arrangement is further
configured for
providing hydraulic pressure to drive a percussion unit 4 and a damper unit 5
of the drilling
machine 3 by means of a first hydraulic circuit 10. The first hydraulic
circuit 10 is fluidly
connected to a first hydraulic pressure source PS1 and a tank arrangement T.
The
hydraulic arrangement is further configured to drive a rotation unit 6 of the
drilling machine
3 by means of a second hydraulic circuit 50. It is to be noted that, although
separate
schematic boxes are used to represent the drilling machine 3 in fig. 5, the
percussion unit
CA 03227348 2024- 1-29
WO 2023/048606
PCT/SE2021/050933
11
4, the damper unit 5 and the rotation unit 6 are provided within the same
drilling machine
3.
The first hydraulic circuit 10 comprises a first hydraulic conduit 11 and a
second hydraulic
conduit 12. The first and second hydraulic conduits 11, 12 are configured so
that
pressurizing one of the first and second hydraulic conduits 11, 12 presses the
rock drilling
machine in a direction toward one of the first and second ends 21, 22 of the
feed beam 2,
respectively. Pressurizing the first hydraulic conduit 11 thus moves the rock
drilling
machine 3 toward the second end 22 of the feed beam 2, and pressurizing the
second
hydraulic conduit 12 moves the rock drilling machine 3 toward the first end 21
of the feed
beam 2.
The first hydraulic circuit 10 further comprises a percussion unit input port
13 for providing
pressurized hydraulic fluid to drive the percussion unit 4, and a percussion
unit return port
14 for returning hydraulic fluid from the percussion unit 4 to the tank. A
first valve
arrangement 15 in the form of a directional valve arrangement is arranged to
fluidly
connect the first and second hydraulic conduits 11, 12 with the percussion
unit input and
return ports 13, 14. The first valve arrangement 15 is configured to assume
three different
valve states as outlined in the following.
When a pressure in the first hydraulic conduit 11 exceeds a predetermined
first threshold,
the first valve arrangement 15 is configured to assume a first state in which
it fluidly
connects the first hydraulic conduit 11 to the percussion unit input port 13,
and in which it
fluidly connects the percussion unit return port 14 to the second hydraulic
conduit 12. In
the illustrated embodiment, the first state is achieved when the first valve
arrangement 15
is moved to the far right.
VVhen a pressure in the second hydraulic conduit 12 exceeds a predetermined
second
threshold, the first valve arrangement 15 is configured to assume a second
state in which
it fluidly connects the second hydraulic conduit 12 to the percussion unit
input port 13, and
in which it fluidly connects the percussion unit return port 14 to the first
hydraulic conduit
11. In the illustrated embodiment, the second state is achieved when the first
valve
arrangement 15 is moved to the far left.
CA 03227348 2024- 1-29
WO 2023/048606
PCT/SE2021/050933
12
VVhen the pressures in the first and the second hydraulic conduits 11, 12 are
both below
the first and the second thresholds, respectively, the first valve arrangement
15 is
configured to assume a closed state in which it fluidly disconnects the first
and second
hydraulic conduits 11, 12 from the percussion unit input and return ports 13,
14. In the
illustrated embodiment, the second state is achieved when the first valve
arrangement 15
is moved to its middle position.
The hydraulic arrangement further comprises a damper input port 30 for
providing
pressurized hydraulic fluid to drive the damper unit 5, configured to ensure
rock contact
during drilling. The damper input port 30 is herein fluidly connected to the
percussion unit
input port 13 between the first valve arrangement 15 and the percussion unit
4. A pilot-
controlled sequential valve arrangement 31 is further arranged between the
damper input
port 30 and the percussion unit 4. The sequential valve arrangement 31 is
configured to
first supply pressurized hydraulic fluid to the damper input port, and only
thereafter, when
a pressure upstream of the sequential valve arrangement 31 exceeds a
predetermined
threshold, supply pressurized hydraulic fluid to drive the percussion unit 4.
For this
purpose, the sequential valve arrangement 31 is movable to an open state
against the
force of a spring member. When in a closed state, the sequential valve
arrangement 31
prevents flow of hydraulic fluid to the percussion unit 4 but allows
pressurizing the damper
unit 5. A return port from the damper unit 5, although, not illustrated, may
be fluidly
connected to the percussion unit return port 14.
A constant flow valve 32 is herein also provided in the damper input port 30,
for providing
a constant flow of hydraulic fluid to the damper unit. Instead of a constant
flow valve,
another kind of flow limiter may be used.
Fig. 6 and fig. 7 show two alternative embodiments of the first valve
arrangement 15, 15'.
In both embodiments, the first valve arrangement 15, 15' is a pilot-controlled
directional
valve arrangement comprising a movable valve body 18 having an internal first
pilot
conduit 16 controlling movement of the valve body 18 to the first state, and
an internal
second pilot conduit 17 controlling movement of the valve body 18 to the
second state. A
first spring member 23 and a second spring member 24 are provided, wherein the
valve
body 18 is movable to the first state against the spring force of the second
spring member
24, and movable to the second state against the spring force of the first
spring member
23. When the hydraulic pressure is insufficient to overcome either of the
spring forces of
CA 03227348 2024- 1-29
WO 2023/048606
PCT/SE2021/050933
13
the first and second spring members 23, 24, the closed state is assumed. The
spring
members 23, 24 are herein pressure springs.
In the embodiment illustrated in fig. 6, the first valve arrangement 15
comprises 7 ports
15A-15G. When the first valve arrangement 15 is in the closed state,
illustrated in fig. 6,
there is no fluid connection between the ports 15A-15G. When the first valve
arrangement
is in its first state, fluid connections are provided between the ports 15A
and 15E,
connecting the first hydraulic conduit 11 to the percussion unit input port
13, and between
the ports 15G and 15B, connecting the percussion unit return port 14 to the
second
10 hydraulic conduit 12. Furthermore, the port 15D is fluidly connected to the
port 15A,
connecting the first hydraulic conduit 11 to the damper input port 30. When
the first valve
arrangement 15 is in its second state, fluid connections are provided between
the ports
15B and 15E, connecting the second hydraulic conduit 12 to the percussion unit
input port
13, and between the ports 15C and 15A, connecting the percussion unit return
port 14 to
15 the first hydraulic conduit 11. The port 15F is now fluidly connected to
the port 15B,
connecting the second hydraulic conduit 11 to the damper input port 30. The
first valve
arrangement 15 illustrated in fig. 6 thus comprises an integrated sequential
valve
arrangement for ensuring that the damper unit 5 is pressurized before the
percussion unit
4.
Fig. 7 shows the first valve arrangement 15' according to another embodiment.
This
embodiment differs from the embodiment illustrated in fig. 6 only in that
there are no ports
15D, 15F provided for connection to the damper unit input port 30. A separate
sequential
valve arrangement 31 may be provided when using the first valve arrangement
15'
according to this embodiment.
The first hydraulic circuit 10 further comprises a second valve arrangement 40
in the form
of a controllable directional valve arrangement, herein configured to be
controlled by an
electronic control unit 70, although other means for controlling the second
valve
arrangement 40 are possible, such as manually, mechanically, or by using
pressure
control. The second valve arrangement 40 is configured to selectively fluidly
connect one
of the first and second hydraulic conduits 11, 12 to the first hydraulic
pressure source
PS1, and the other one of the first and second hydraulic conduits to the tank
arrangement
T. The second valve arrangement 40 has a similar configuration as the first
valve
arrangement 15 but is configured to be actively controlled instead of actuated
CA 03227348 2024- 1-29
WO 2023/048606
PCT/SE2021/050933
14
automatically according to relative pressures in the conduits. Thus, in a
first state of the
second valve arrangement 40, it connects the first pressure source PS1 to the
second
hydraulic conduit 12, and the first hydraulic conduit 11 to the tank
arrangement T. In a
second state, it connects the first hydraulic conduit 11 to the first pressure
source PS1
and the second hydraulic conduit 12 to the tank arrangement T. In this way,
the direction
of movement of the drilling machine 3 along the feed beam 2 may be controlled.
In a
closed state, no hydraulic pressure is provided to the hydraulic conduits 11,
12.
The second hydraulic circuit 50 is arranged in parallel with the first
hydraulic circuit 10. It
is herein illustrated to be controlled by the same control unit 70, but of
course a separate
control unit may be provided. The second hydraulic circuit 50 comprises a
hydraulic flow
source FS, configured to provide a controllable flow of hydraulic fluid, and a
second
pressure source PS2. It further comprises third and fourth hydraulic conduits
53, 54
configured so that pressurizing one of the third and fourth hydraulic conduits
53, 54
presses the rock drilling machine 3 in a direction toward one of the first and
second ends
21, 22 of the feed beam 2, respectively. Thus, similarly as the first and
second hydraulic
conduits 11, 12, the third and fourth hydraulic conduits 53, 54 are used for
moving the
drilling machine 3. The direction and speed of movement of the drilling
machine 3 along
the feed beam 2 will thus depend on the relative pressures within all these
four conduits
11, 12, 53, 54.
The second hydraulic circuit 50 further comprises a first rotation unit port
51, a second
rotation unit port 52, and a third valve arrangement 60 in the form of a
controllable
directional valve arrangement. It also comprises a fourth valve arrangement 45
arranged
to fluidly connect either one of the third and the fourth hydraulic conduits
53, 54 to the
second rotation unit port 52 in dependence on a pressure in the third and
fourth hydraulic
conduits 53, 54, respectively. The fourth valve arrangement 45 is further
configured to
close the high-pressure side, i.e. the one of the third and the fourth
hydraulic conduits 53,
54 in which the pressure is higher. If a pressure in the third hydraulic
conduit 53 exceeds
the pressure in the fourth hydraulic conduit 54, the fourth valve arrangement
45 assumes
a first state in which it fluidly connects the fourth hydraulic conduit 54 to
the second
rotation unit port 52 and closes the third hydraulic conduit 53. If a pressure
in the fourth
hydraulic conduit 54 exceeds the pressure in the third hydraulic conduit 53,
the fourth
valve arrangement 45 assumes a second state in which it fluidly connects the
third
hydraulic conduit 53 to the second rotation unit port 52 and closes the fourth
hydraulic
CA 03227348 2024- 1-29
WO 2023/048606
PCT/SE2021/050933
conduit 54. The fourth valve arrangement 45 according to an example embodiment
is
shown in greater detail in fig. 8. As can be seen, the valve arrangement 45 is
herein
provided with internal pilot conduits 46, 47, but no spring members.
5 The third valve arrangement 60 is configured to selectively connect the
first rotation unit
port 51 to either the hydraulic flow source FS or the tank arrangement T. It
is further
configured to selectively fluidly connect one of the third and fourth
hydraulic conduits 53,
54 to the second hydraulic pressure source PS2, and the other one of the third
and fourth
hydraulic conduits 53, 54 to the tank arrangement T. For this purpose, the
third valve
10 arrangement 60 comprises a first directional valve unit 61 movable between
three valve
states, and a second directional valve unit 62, herein movable between two
valve states.
The first and second directional valve units 61, 62 are individually
controllable by the
control unit 70, but may also be controllable by other means, such as
mechanically or by
using pressure control.
The first directional valve unit 61 has a similar configuration as the second
valve
arrangement 40. In a first state of the first directional valve unit 61, it
connects the second
pressure source PS2 to the fourth hydraulic conduit 54, and the third
hydraulic conduit 53
to the second directional valve unit 62. In a second state, it connects the
third hydraulic
conduit 53 to the second pressure source PS2 and the fourth hydraulic conduit
54 to the
second directional valve unit 62. In a closed state, no hydraulic pressure is
provided to the
hydraulic conduits 53, 54 from the pressure source PS2. By controlling the
first directional
valve unit 61, the direction of movement of the feed beam 2 can be controlled.
The second valve arrangement 62 is herein a two-position valve. In a first
state thereof, it
connects the hydraulic flow source FS to the first rotation unit port 51, and
the tank
arrangement T to the first directional valve unit 61. In a second state
thereof, it connects
the hydraulic flow source FS to the first directional valve unit 61, and the
tank
arrangement T to the first rotation unit port 51. Of course, instead of a two-
position valve,
a three-position valve similar to the first directional valve unit 61 could be
used as the
second directional valve unit. By controlling the second directional valve
unit 62, the
rotational direction and rotational speed of the rotation unit 6 can be
controlled.
In this way, the third and fourth hydraulic conduits 53, 54 are only fluidly
connectable to
the tank arrangement T and to the hydraulic flow source FS via a combination
of the first
and second directional valve units 61, 62. The third and fourth hydraulic
conduits 53, 54
CA 03227348 2024- 1-29
WO 2023/048606
PCT/SE2021/050933
16
are fluidly connectable to the second hydraulic pressure source PS2 via the
first
directional valve unit 61 only. The first rotation unit port 51 is fluidly
connectable to either
one of the hydraulic flow source FS and the tank arrangement T via the second
directional
valve unit 62 only.
By means of the hydraulic arrangement according to the present disclosure, the
drilling
machine 3 can be operated in several different operational modes depending on
the
states of the second and third valve arrangements 40, 60, and the hydraulic
pressures
applied by the pressure sources PS1, PS2 and by the hydraulic flow source FS.
For example, during a rock drilling operation, the second valve arrangement 40
is
controlled to its second state, so that the first hydraulic conduit 11 is
connected to the first
pressure source PS1, and the second hydraulic conduit 12 is connected to the
tank
arrangement T. The first pressure source PSI is controlled to obtain a
pressure suitable
for drilling, above the second threshold. The drilling machine 3 is thus
pressed toward the
second end 22 and the percussion unit 4 is pressurized by the first hydraulic
conduit 11.
Thus, the first hydraulic circuit 10 on one hand presses the drilling machine
3 in a forward
direction along the feed beam 2, and on the other hand drives the percussion
unit 4 and
the damper unit 5. In the second hydraulic circuit 50, the first directional
valve unit 61 is
controlled to its second state, connecting the second pressure source PS2 to
the third
hydraulic conduit 53, thereby applying a force that cooperates with that
applied by the first
pressure source PS1 to feed the drilling machine 3 toward the second end 22 of
the feed
beam 2, i.e., the front end. The second pressure source PS2 is controlled to
obtain a
suitable resulting force for moving the drilling machine 3 along the feed beam
2. The
second directional valve unit 62 is controlled to its first state, in which
the hydraulic flow
source FS is connected to the first rotation unit port 51 to drive the
rotation unit 6. The
return flow from the rotation unit will automatically pass through a low-
pressure side of the
second hydraulic circuit 50 via the fourth valve arrangement 45. Since the
third hydraulic
conduit 53 is pressurized, the return flow will pass through the fourth
hydraulic conduit 54
and to the tank arrangement T via the first and second directional valve units
61, 62.
If the drilling machine 3 gets stuck during a drilling operation and needs to
be pulled free,
the second valve arrangement 40 and the first directional unit 61 are both
controlled to
their first states, so that a pressure is applied to press the drilling
machine in a rearward
direction toward the first end 21 of the feed beam 2. The first and second
pressure
CA 03227348 2024- 1-29
WO 2023/048606
PCT/SE2021/050933
17
sources PS1, PS2 may be controlled to apply up to a maximum pressure. The
second
directional valve unit 62 is controlled to its first state.
In another example, the hydraulic arrangement is controlled to unthread the
drilling
machine 3 without driving the percussion unit 4. In this case, the second
valve
arrangement 40 may be controlled to its second state, so that the first
hydraulic conduit 11
is connected to the first pressure source PS1, thereby pushing the drilling
machine in a
forward direction toward the second end 22 of the feed beam. The first
pressure source
PS1 is however controlled to deliver a pressure below the first threshold, so
that the first
valve arrangement 15 remains in its closed state. The first directional valve
unit 61 is
controlled to its first state, thus using the second pressure source PS2 to
pressurize the
fourth hydraulic conduit 54, counteracting the pressure applied by the first
pressure
source PS1. The second pressure source PS2 is controlled to provide a suitable
pressure
to feed the drilling machine 3 in a desired direction and speed along the feed
beam 2. The
second directional valve unit 62 is controlled to its second state, in which
it connects the
hydraulic flow source FS to the first directional valve unit 61, so that the
hydraulic flow for
driving the rotation unit 6 is delivered via the third hydraulic conduit 53,
at a lower
pressure than that applied by the second pressure source PS2. Since the
pressure is
higher in the fourth hydraulic conduit 54 than in the third hydraulic conduit
53, the fourth
valve arrangement 45 will automatically be controlled to its second state,
connecting the
second rotation unit port 52 to the third hydraulic conduit 53. The rotation
unit 6 will thus
rotate in an opposite direction compared to the drilling operation.
As an alternative to the internal pilot conduits 16, 17 of the first valve
arrangement 15,
external hoses could be provided as pilot conduits. Alternatively, it would be
possible to
use an electronic control unit (not shown) configured to automatically control
the first valve
arrangement 15 in response to pressure signals from pressure sensors in the
first and
second hydraulic conduits 16, 17. The same is applicable to the fourth valve
arrangement
45.
The first valve arrangement 15 as well as the fourth valve arrangement 45 may
be
arranged in the rock drilling machine 3, or in the slidable carrier 35 on
which the rock
drilling machine 3 is mounted, or in the drilling machine connector 26.
CA 03227348 2024- 1-29
WO 2023/048606
PCT/SE2021/050933
18
In alternative embodiments, the damper unit input port 30 may be included in
the second
hydraulic circuit 50 instead of in the first hydraulic circuit. In this case,
there is no need for
a sequential valve arrangement, since the third valve arrangement 60 can be
controlled to
pressurize the damper input port 30 independently of when the percussion unit
input port
13 is pressurized. Thus, it can be ensured that the damper unit is 5 is
pressurized before
pressurizing the percussion unit 4.
The hydraulic pressure sources PSI, PS2 and the hydraulic flow source FS may
be
controllable hydraulic pumps, wherein the first and second pressure sources
PS1, PS2
are controllable to provide a desired pressure, and the hydraulic flow source
FS is
controllable to provide a desired flow rate. This may also be achieved by
adjustable flow
limiters or similar.
In the shown embodiment, the first and second hydraulic conduits 11, 12 are
both fluidly
connected to the same second valve arrangement 40, and the third and fourth
hydraulic
conduits are both connected to the same third valve arrangement 60. However,
in other
embodiments, it is possible to, e.g., connect the first and fourth hydraulic
conduits 11, 54
to a common valve arrangement, and similarly connect the second and third
hydraulic
conduits 12, 53 to another common valve arrangement.
Generally, all terms used herein are to be interpreted according to their
ordinary meaning
in the relevant technical field, unless a different meaning is clearly given
and/or is implied
from the context in which it is used.
Reference has been made herein to various embodiments. However, a person
skilled in
the art would recognize numerous variations to the described embodiments that
would still
fall within the scope of the claims.
Any feature of any of the embodiments disclosed herein may be applied to any
other
embodiment, wherever suitable. Likewise, any advantage of any of the
embodiments may
apply to any other embodiments, and vice versa.
In the drawings and specification, there have been disclosed exemplary aspects
of the
disclosure. However, many variations and modifications can be made to these
aspects
without substantially departing from the principles of the present disclosure.
Thus, the
disclosure should be regarded as illustrative rather than restrictive, and not
as being limited
to the particular aspects discussed above. Accordingly, although specific
terms are
CA 03227348 2024- 1-29
WO 2023/048606
PCT/SE2021/050933
19
employed, they are used in a generic and descriptive sense only and not for
purposes of
limitation.
Hence, it should be understood that the details of the described embodiments
are merely
examples brought forward for illustrative purposes, and that all variations
that fall within the
scope of the claims are intended to be embraced therein.
CA 03227348 2024- 1-29
