Classifications

• • E—FIXED CONSTRUCTIONS
  • E21—EARTH OR ROCK DRILLING; MINING
  • E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
  • E21B7/00—Special methods or apparatus for drilling
  • E21B7/02—Drilling rigs characterised by means for land transport with their own drive, e.g. skid mounting or wheel mounting
  • E21B7/025—Rock drills, i.e. jumbo drills
• • E—FIXED CONSTRUCTIONS
  • E21—EARTH OR ROCK DRILLING; MINING
  • E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
  • E21B19/00—Handling rods, casings, tubes or the like outside the borehole, e.g. in the derrick; Apparatus for feeding the rods or cables
  • E21B19/08—Apparatus for feeding the rods or cables; Apparatus for increasing or decreasing the pressure on the drilling tool; Apparatus for counterbalancing the weight of the rods
  • E21B19/086—Apparatus for feeding the rods or cables; Apparatus for increasing or decreasing the pressure on the drilling tool; Apparatus for counterbalancing the weight of the rods with a fluid-actuated cylinder

Definitions

• 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.
• 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.
• hose suspension arrangements for providing hydraulic pressure are often both bulky and exposed to harsh conditions.
• 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 problems occur due to damages on hydraulic hoses, including external damages and ruptures thereof.
• a primary object of the present disclosure is to achieve an in at least some aspect improved hydraulic arrangement for a rock drilling machine.
• 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.
• 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:
• 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
• 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: o 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, 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.
• 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.
• the percussion unit 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.
• the percussion unit input port 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.
• the percussion unit input port 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.
• the first valve arrangement is a pilot-controlled directional valve arrangement.
• a pilot-controlled valve arrangement i.e. a valve arrangement comprising one or two pilot conduit(s) for controlling the state
• 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.
• 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.
• 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.
• the first valve arrangement is arranged in the rock drilling machine, or in a slidable carrier on which the rock drilling machine is mounted.
• 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.
• the damper input port may be fluidly connected to the percussion unit input port, or alternatively to a rotation unit port of the hydraulic arrangement, configured for driving a rotation unit, i.e. a hydraulic motor of the rock drilling machine.
• the hydraulic arrangement comprises a sequential valve arrangement configured to first supply pressurized hydraulic fluid to the damper input port, and only thereafter supply pressurized hydraulic fluid to drive the percussion unit.
• 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.
• the damper input port is fluidly connected to the percussion unit input port between the first valve arrangement and the percussion unit.
• the sequential valve arrangement is integrated with the first valve arrangement.
• 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.
• 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.
• 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.
• the damper unit input port and return port may form part of the second hydraulic circuit instead of the first hydraulic circuit.
• 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.
• 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.
• the second hydraulic circuit comprises:
• first rotation unit port a first rotation unit port
• second rotation unit port a second rotation unit port
• 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.
• 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.
• the drilling machine will move along the feed beam in dependence 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.
• 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.
• 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.
• the first directional valve unit may be used for controlling a feeding direction for movement of the drilling machine
• the second directional valve unit may be used for controlling a direction of rotation of the rotation unit.
• 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.
• 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.
• a 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 hydraulic arrangement is fluidly connectable to the at least one hydraulic pressure source and to the tank arrangement.
• 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
• 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.
• 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.
• Fig. 8 is a cross-sectional view of another valve within the hydraulic arrangement.
• 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.
• 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.
• 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 22k- 22C of the feed beams 2A-2C.
• 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.
• hydraulic sources are arranged to provide hydraulic fluid to hydraulic motors such as hydraulic cylinders arranged to advance the rock drilling machines 3A-3C along the corresponding feed beams 2A-2C.
• 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.
• 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 A1 between the first end 21 and the second end 22.
• a rock drilling machine 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 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.
• the rock drilling machine 3 is positioned in a most retracted position at the first end 21 of the feed beam 2.
• 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 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
• 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.
• the first valve arrangement 15 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.
• the first valve arrangement 15 When 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.
• the second state is achieved when the first valve arrangement 15 is moved to the far left.
• 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.
• 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.
• 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.
• a constant flow valve instead of a constant flow valve, another kind of flow limiter may be used.
• 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.
• the spring members 23, 24 are herein pressure springs.
• the first valve arrangement 15 comprises 7 ports 15A-15G.
• the first valve arrangement 15 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.
• the first valve arrangement 15 When the first valve arrangement 15 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 hydraulic conduit 12.
• the port 15D is fluidly connected to the port 15A, connecting the first 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 automatically according to relative pressures in the conduits.
• the second valve arrangement 40 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.
• 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.
• 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 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.
• 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.
• the third valve 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.
• a three-position valve similar to the first directional valve unit 61 could be used as the second directional valve unit.
• 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 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.
• 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.
• 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 PS1 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.
• 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.
• 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.
• 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 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.
• the hydraulic arrangement is controlled to unthread the drilling machine 3 without driving the percussion unit 4.
• 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.
• 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.
• 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 PS1 , 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.
• 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.

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• 2021
  • 2021-09-24 EP EP21787085.6A patent/EP4405558B1/de active Active
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