CN114746619A

CN114746619A - Method performed by a control device for changing a drill bit in a rock drilling unit, control device for a rock drilling unit, rock drilling unit and rock drilling rig

Info

Publication number: CN114746619A
Application number: CN202080082004.2A
Authority: CN
Inventors: 安德斯·赫尔曼
Original assignee: Atlas Copco Rock Drills AB
Current assignee: Epiroc Rock Drills AB
Priority date: 2019-12-20
Filing date: 2020-11-25
Publication date: 2022-07-12
Also published as: SE1951523A1; KR20220113981A; EP4077869A1; WO2021126038A1; SE543995C2; JP2023508315A

Abstract

The invention relates to a method performed by a control device (100) for changing a drill bit (3) in a rock drilling unit (8), the drill bit (3) being configured to be connected to at least one drill rod (7) by a first threaded connection (40), the rock drilling unit (8) comprising: a first feeding device (42), the first feeding device (42) being used for feeding at least one drill rod (7) and a drill bit (3) along the axial direction; a rotation device (44), the rotation device (44) being configured to generate a rotational movement of the at least one drill rod (7) and the drill bit (3); a percussion device (46), the percussion device (46) being adapted to provide percussion pulses on at least one drill rod (7) and drill bit (3); and a drill bit changer (1), the drill bit changer (1) being for changing a drill bit (3) on at least one drill rod (7), the method comprising: receiving (s101) information about replacing the drill bit (3); controlling (s102) the percussion device (46) to impact the drill bit (3) against the bottom (48) of the formed borehole (50) so as to loosen the first threaded connection (40) between the drill bit (3) and the at least one drill rod (7); controlling (s103) the first feeding means (42) to move the at least one drill rod (7) and the drill bit (3) out of the borehole (50); controlling (s104) the rotating device (44) to remove the drill bit (3) from the at least one drill rod (7); controlling (s105) the drill changer (1) to change and replace the drill (3); and controlling (s106) the rotation device (44) to attach the at least one drill rod (7) to the drill bit (3) through the first threaded connection (40). The invention also relates to a control arrangement (100), a rock drilling unit (8) and a rock drilling rig (5).

Description

Method performed by a control device for changing a drill bit in a rock drilling unit, control device for a rock drilling unit, rock drilling unit and rock drilling rig

Technical Field

The present disclosure relates to a method performed by a control device for changing a drill bit in a rock drilling unit, a control device for a rock drilling unit, a rock drilling unit and a rock drilling rig. The disclosure also relates to a computer program and a computer readable medium.

Background

When performing drilling operations in rock-like materials, special types of drilling machines are often used. There are different types of drilling rigs, of which the "DTH" (down hole) drilling rig and the top hammer drilling rig are two common drilling rigs for performing such operations in or close to the vertical direction. Since rock drilling is performed in hard materials, a special kind of drill bit is used for this operation. Such drill bits are often heavy and may become dirty with oil when in use, and may also contain sharp edges and/or material chips after use that may cause injury to people when handling such drill bits. However, the drill bits will need to be serviced in the form of replacement and/or regrinding, which in turn results in the need to frequently remove and attach the drill bits to the drilling rig.

DTH drills typically include a splined connection for attaching a drill bit to such drills, whereas top hammer drills typically utilize a threaded connection instead. Bit change systems are known which can provide a fully or semi-automatic replacement process for a drilling rig. The bit changing system is designed differently for DTH and top hammer drilling rigs.

Disclosure of Invention

Due to the above characteristics and handling around the drill bit, such removal and attachment operations are cumbersome, inconvenient, and sometimes personal injury.

Accordingly, there is a need for an improved method for replacing and handling such drill bits. There is also a need to develop an improved control arrangement configured to perform a bit change operation on a rock drilling unit automatically or at least semi-automatically. It is also desirable to develop a rock drilling unit comprising such a control device, a rock drilling rig comprising such a rock drilling unit, a computer program and a computer readable medium for performing the method. There is also a need to develop a rock drilling unit and a rock drilling rig that can be controlled automatically.

It is therefore an object of the present invention to provide an improved method for replacing and handling drill bits. Another object is to develop an improved control arrangement configured to perform a bit change operation on a rock drilling unit automatically or at least semi-automatically. Further objects are to develop a rock drilling unit comprising such a control device, a rock drilling rig comprising such a rock drilling unit, a computer program and a computer readable medium, respectively, for performing the method. Another object is to develop a rock drilling unit and a rock drilling rig that can be controlled automatically.

These objects are achieved by a method for changing a drill bit in a rock drilling unit, a control device for a rock drilling unit, a rock drilling unit and a rock drilling rig, a computer program and a computer readable medium according to the appended claims, which are performed by the control device.

According to an aspect of the invention, a method performed by a control apparatus for replacing a drill bit in a rock drilling unit is provided. The drill bit is configured to be connected to at least one drill rod by a first threaded connection. The rock drilling unit comprises: a first feeding device for feeding at least one drill rod and a drill bit in an axial direction; a rotation device configured to generate a rotational movement of the at least one drill rod and the drill bit; a percussion device for providing percussion pulses on at least one drill rod and drill bit; and a bit changer for changing a bit on at least one drill rod, the method comprising: receiving information regarding bit replacement; controlling the percussion device to strike the drill bit against the bottom of the formed borehole, thereby loosening the first threaded connection between the drill bit and the at least one drill rod; controlling the first feeding device to move the at least one drill rod and the drill bit out of the borehole; controlling the rotating device to remove the drill bit from the at least one drill rod; controlling the bit changer to change and replace the bit; and controlling the rotation device to attach the at least one drill rod to the drill bit through the first threaded connection.

This has the following advantages: the instructions from the control device may control the first feeding device, the rotating device and the percussion device for changing the drill bit by means of the drill bit changer. The instructions from the control device may be based on information received from the sensors and from empirical data. The control device may be configured to initiate replacement of the drill bit based on operational data of the drilling rig and the drill bit connected to the drilling rig. Thus, a bit change operation may be automatically initiated between drilling operations in case a need for such an operation is detected based on the operation data. The operational data may be data comprising any one or combination of the following: drilling time spent, drilling time spent since last maintenance, expected time remaining until replacement is needed, meters drilled since last maintenance, or others. Thus, the control device may initiate a bit change operation if the current state of the drill bit is deemed unsuitable for drilling in the upcoming drilling operation. Thus, a plurality of drilling operations can be performed one after the other in a safe, fast and efficient manner. The object of providing an improved method for exchanging and handling drill bits is thus achieved.

According to an aspect of the invention, a computer program comprises instructions which, when executed by a computer, cause the computer to carry out the method. A computer-readable medium comprising instructions which, when executed by a computer, cause the computer to implement the method. This has the following advantages: the method may be included in pre-programmed software that may be implemented into a drilling unit adapted to utilize such a method.

According to an aspect of the invention, a control arrangement of a rock drilling unit is provided. The rock drilling unit comprises: a drill bit configured to be connected to at least one drill rod by a first threaded connection; a first feeding device for feeding at least one drill rod and a drill bit in an axial direction; a rotation device configured to generate a rotational movement of the at least one drill rod and the drill bit; a percussion device for providing percussion pulses on at least one drill rod and drill bit; and a bit changer for changing a bit on at least one drill rod, the control device being configured to: receiving information regarding bit replacement; controlling the percussion device to strike the drill bit against the bottom of the formed borehole, thereby loosening the first threaded connection between the drill bit and the at least one drill rod; controlling the first feeding device to move the at least one drill rod and the drill bit out of the borehole; controlling the rotating device to remove the drill bit from the at least one drill rod; controlling the bit changer to change and replace the bit; and controlling the rotation device to attach the at least one drill rod to the drill bit through the first threaded connection.

This has the following advantages: the bit change operation of the rock drilling unit may be performed automatically. The first feeding means, the rotating means, the percussion device and the drill bit changer are controlled by a control unit to automatically change the drill bit in a safe manner. Drill bits that may be heavy, sharp and/or inconvenient to hold and handle may be handled completely by means of instructions from the control device. The bit change operation is performed by the control means and may be based on information received from the sensors and from empirical data. The control device may be configured to initiate replacement of the drill bit based on operational data of the drilling rig and the drill bit connected to the drilling rig. Thus, a bit change operation may be automatically initiated between drilling operations in case a need for such an operation is detected based on the operation data.

According to an aspect of the invention, a rock drilling unit is provided, wherein the rock drilling unit comprises at least one control apparatus disclosed herein. The rock drilling unit comprises a first feeding device, a rotation device, a percussion device and a bit changer controlled by a control unit to automatically change the drill bit. This has the following advantages: the rock drilling unit may be arranged in a rock drilling machine in order to achieve an automatically performed bit change operation.

According to an aspect of the invention, there is provided a rock drilling rig comprising a rock drilling unit as disclosed herein. Different types of drilling machines can be used according to the requirements of typical rock drilling. According to an aspect, the rock drilling machine may be configured for vertical drilling or drilling in an angled direction in the range of about 0 ° to about 95 ° relative to the vertical line. Such a rock drilling machine may be a top hammer drill, which attaches a drill bit to the rock drilling machine with a threaded connection.

Other objects, advantages and novel features of the invention will become apparent to those skilled in the art from the following detailed description and by putting the invention into practice. Although embodiments of the invention are described below, it should be noted that the invention is not limited to the specific details described. Those skilled in the art who have access to the teachings herein will recognize additional applications, modifications, and combinations within the scope of the present invention, and in other fields.

Drawings

For a more complete understanding of the present disclosure, and for further objects and advantages thereof, reference should be made to the following detailed description, taken in conjunction with the accompanying drawings, in which like reference characters refer to like items throughout the various figures, and in which:

figure 1 illustrates a perspective view of a rock drilling machine according to an example;

figure 2 schematically illustrates a side view of a rock drilling unit according to an example;

FIG. 3 illustrates a perspective view of a drill bit changer, according to an example;

figure 4 schematically illustrates a perspective view of a clamp arm of a bit changer according to an example;

FIG. 5 shows a flow diagram of a method according to an example;

FIG. 6 shows a flow diagram of a method according to an example; and

fig. 7 schematically illustrates a control device or computer according to an embodiment.

Detailed Description

The detailed description with reference to the depicted examples will be considered to be examples including combinations of certain features, which have been described in detail above. Thus, it should be understood that additional examples may be implemented by combining other features into examples not described herein. The figures are to be regarded as examples and not mutually exclusive combinations. It should also be noted that all the figures shown and described are schematically represented, wherein for the sake of simplicity common parts of machinery or the like are not depicted.

According to an aspect of the disclosure, a method performed by a control apparatus for replacing a drill bit in a rock drilling unit is provided. The drill bit is configured to be connected to at least one drill rod by a first threaded connection. The rock drilling unit comprises: a first feeding device for feeding at least one drill rod and a drill bit in an axial direction; a rotation device configured to generate a rotational movement of the at least one drill rod and the drill bit; a percussion device for providing percussion pulses on at least one drill rod and drill bit; and a bit changer for changing a bit on at least one drill rod, the method comprising: receiving information regarding bit replacement; controlling the percussion device to strike the drill bit against the bottom of the formed borehole, thereby loosening the first threaded connection between the drill bit and the at least one drill rod; controlling the first feeding device to move the at least one drill rod and the drill bit out of the borehole; controlling the rotating device to remove the drill bit from the at least one drill rod; controlling the bit changer to change and replace the bit; and controlling the rotation device to attach the at least one drill rod to the drill bit through the first threaded connection.

The control device may be arranged on the rock drilling unit or at a distance from the rock drilling unit. The control device may be connected to a sensor arranged on the rock drilling unit or at a component connected to the rock drilling unit. Such sensors may detect an activity or characteristic of the rock drilling unit or of a component connected to the rock drilling unit. The control means may comprise a memory in which empirical data may be stored.

The drill bit is suitable for rock drilling in hard materials. The drill bit may be designed and provided with a shape adapted to the drilling operation to be performed. Such bits are typically heavy and may have sharp edges and/or chips of material after use. The drill bit is provided with a thread adapted to be connected to a corresponding thread on the drill rod to form a first threaded connection.

The rock drilling unit may comprise an elongated frame or beam on which the first feeding device, the rotation device and the percussion device are arranged. The rock drilling unit may be arranged on and connected to the vehicle by means of a boom, so that the rock drilling unit may be arranged in different positions in relation to the vehicle and the rock to be drilled. The rock drilling unit, the boom and the vehicle together form a rock drilling rig. The drilling unit may be configured for vertical drilling, which is considered to be completely vertical or to some extent deviated from the vertical. Thus, the drilling unit may be able to tilt and drill in an angled direction in the range of about 0 ° to about 95 ° relative to a vertical line without departing from the scope of the present disclosure. In a rock drilling machine, such a rock drilling unit configured for vertical drilling or drilling in an angled direction in the range of about 0 ° to about 95 ° with respect to the vertical line may be configured as a top hammer drill.

The drilling unit may also be provided with a bit changer, which assists in the automatic changing of the drill bit. The drill bit changer may comprise a drill bit storage arranged adjacent and parallel to the drilling central axis of the rock drilling unit and arranged to hold a plurality of drill bits and move the drill bits between storage positions comprised by the drill bit storage and exchange positions. The drill bit storage means may have the shape of a cylindrical drum, wherein the movement between inner positions within the drill bit storage means may be performed by rotation of such cylindrical storage means or by means of rotation of inner parts of the cylindrical storage means. The drill bit storage device may of course have other designs without departing from the scope of the disclosure herein.

The rock drilling unit may also be provided with a rod handling system comprising a clamping element for a drill rod. The rod handling system includes a magazine of drill rods. The drill rod may be brought out of the magazine by the gripping elements during a drilling operation for assembling the drill string with the drill rod, and may thus be drilled deeper into the rock. When changing the drill bit, the drill rods are detached from each other and are brought back to the magazine by the clamping element in succession.

The first feeding device is configured for feeding the drill rod and the drill bit in an axial direction both during the drilling operation and during the replacement of the drill bit. The first feed device may be driven axially by means of a hydraulic or pneumatic actuator relative to the rock drilling unit and in the direction of the drilling centre axis.

The rotating means configured to generate a rotational movement of the drill rod and the drill bit may be driven by a first hydraulic or pneumatic machine. The percussion device for providing impact pulses on the at least one drill rod and drill bit may be driven by a second hydraulic or pneumatic machine. The impact pulses are provided on the drill rod in the direction of the drilling centre axis, and the impact pulses are transmitted from the drill rod to the drill bit.

The control device may receive information from a memory storing operational data by method steps of receiving information regarding changing bits. Alternatively or in combination, the control device may receive information from the device providing the operational data. The operational data may be data comprising any one or combination of the following: drilling time spent, drilling time spent since last maintenance, expected time remaining until replacement is needed, meters drilled since last maintenance, or others.

The control device communicates with the percussion device and sends a signal for controlling the percussion device by the method steps of controlling the percussion device to press the drill bit against the bottom of the formed drill hole to loosen the first threaded connection between the drill bit and the at least one drill rod. The time, frequency and force of punching the drill bit can be controlled according to the type of rock and the type of drill bit used.

By the method step of controlling the first feeding means to move the at least one drill rod and the drill bit out of the borehole, the control means communicates with the first feeding means and sends a signal for controlling the first feeding means. The feed rate and the feed distance of the first feeding means may be controlled in dependence of the depth of the drill hole in the rock.

By the method step of controlling the rotation device to remove the drill bit from the at least one drill rod, the control device communicates with the rotation device and sends a signal for controlling the rotation device. The rotation speed and torque of the rotating means may be controlled in accordance with the state of the first threaded connection.

The control device communicates with the bit changer and sends signals for controlling the bit changer by the method steps of controlling the bit changer to change and replace bits. The control device may thus control the drill bit storage device and the gripper arm comprised in the drill bit changer.

The method step of attaching at least one drill rod to the drill bit through the first threaded connection by controlling the rotation device, the control device communicating with the rotation device and sending a signal for controlling the rotation device. The rotational speed and torque of the rotating means may be controlled depending on the type of drill rod, drill bit and/or the type of first threaded connection between drill rod and drill bit.

A fast and efficient method for automatically or at least semi-automatically changing a drill bit in a rock drilling unit is provided. The method makes it possible to handle potentially harmful drill bits and potentially additional coupling parts thereof without manual work, which in turn provides increased safety and personal safety at the drilling site where the method is carried out. It should be appreciated that the methods presented herein may provide additional benefits associated with various optional features of bit changers according to the present disclosure.

According to an aspect, after controlling the bit changer to change the drill bit, and before controlling the rotation device to attach the at least one drill rod to the drill bit by the first threaded connection, the method further comprises: controlling a second feed device of the rock drilling unit to move the support device to a position in which the support device abuts the drill bit.

In this method step, the control device communicates with the second feeding device and sends a signal for controlling the second feeding device. The feed rate and the feed distance of the second feeding means may be controlled according to the type of drill. The second feed device may be driven axially by means of a hydraulic or pneumatic actuator relative to the rock drilling unit and in the direction of the drilling centre axis. The support device may be a lower support device of the rock drilling unit arranged for supporting and/or holding/clamping a drill bit or drill rod. Thus, the drill bit may be supported by the support means such that the drill bit rests on or abuts the support means. Alternatively, the support means is moved to a position where the support means is able to grip the drill bit. In case the drill bit can be supported by the support means, the support means should be arranged below the drill bit in order to support the drill bit from below when the drill bit is held by the clamping device. An advantage of moving the support device to a position where the support device supports the drill bit from below is that a variety of drill bits having different designs may be exchanged in the rock drilling unit. Since the type and design of the drill bit may vary depending on the type of drilling machine, the gripping means may not be able to hold the drill bit without additional lower supports, which may thus be provided by the support means. By means of such a synchronized movement of the clamping device and the bearing arrangement, the replacement of the drill bit can thus increase its use and be used for various types of drilling units. The support means of the drilling unit may comprise two hydraulically controlled clamping devices arranged circumferentially around the drilling centre axis and at separate positions along the drilling centre axis. Moving the gripping devices to a position close to each other will provide support under the drill bit. The support means may be connected to the control means.

According to an aspect, after controlling the first feeding means to move the at least one drill rod and the drill bit out of the borehole, and before controlling the rotating means to remove the drill bit from the at least one drill rod, the method further comprises: controlling a gripping element of the rod handling system to grip at least one drill rod connected to the rotating device; and controlling the rotation device to tighten a second threaded connection between the at least one drill rod and the rotation device.

In this method step, the control device communicates with the clamping element and the rotating device of the rod handling system and thus sends signals for controlling the clamping element and the rotating device of the rod handling system. During the step of punching the drill bit against the bottom of the formed bore hole thereby loosening the first threaded connection between the drill bit and the at least one drill rod, the second threaded connection between the drill rod and the rotation means may also be loosened. The gripping elements of the magazine for taking and placing the drill rod from and into the magazine of the rod handling system may be controlled to firmly grip the drill rod connected to the rotation device for tightening the second threaded connection between the at least one drill rod and the rotation device. Thereafter, the rotation means may be controlled to tighten the second threaded connection.

According to an aspect, the receiving of the information about the replacement of the drill bit is based on the drilling conditions of the drill bit.

By means of the method steps, the control device can receive information from a sensor or similar detector element. For example, a sensor or similar detector element may sense any differences or characteristics in torque from the rotating device and/or characteristics from the percussion device to determine the condition of the drill bit.

According to one aspect, controlling a bit changer to change and replace a bit comprises: the drill bit is moved from the drilling centre axis to the drill bit storage by means of the gripper arm, and subsequently a new drill bit is taken out of the drill bit storage and moved to the drilling centre axis.

The drill bit storage means may comprise a plurality of storage positions for holding drill bits. Each storage location may hold one drill bit, which may be a drill bit ready for use or a drill bit used in a previous drilling operation. The exchange position may be a single position within the storage from which the drill bit may be removed or positioned, wherein the internal movement of the storage may be used to position the desired slot for holding a particular drill bit at the exchange position. The drill bit changer may further comprise a gripper arm comprising a gripping device configured for selectively gripping the drill bit, the gripper arm being arranged to move the gripping device between the exchange position and a drilling centre axis of the drilling unit. The gripping arm and gripping means may be hydraulically controlled, wherein the movements and gripping of the gripping arm and gripping means may be applied with high precision and large forces are applied to the function. Furthermore, since the gripping arm only needs to be moved to a single position within the drill bit storage device, the movement of the gripping arm can be performed by means of a pivoting movement, which reduces the complexity of the design of the gripping arm and the gripping arm.

The present disclosure also relates to a computer program comprising instructions which, when the program is executed by a computer, cause the computer to carry out the above disclosed method. The invention also relates to a computer-readable medium comprising instructions which, when executed by a computer, cause the computer to carry out the above disclosed method. The method may be included in pre-programmed software that may be implemented into a drilling unit adapted to utilize the method. The pre-programmed software may be stored in the control means. Alternatively or in combination, the software may be stored in a memory or computer located at a distance from the control device.

Furthermore, the present disclosure relates to a control arrangement of a rock drilling unit, the rock drilling unit comprising: a drill bit configured to be connected to at least one drill rod by a first threaded connection; a first feeding device for feeding at least one drill rod and a drill bit in an axial direction; a rotation device configured to generate a rotational movement of the at least one drill rod and the drill bit; a percussion device for providing percussion pulses on at least one drill rod and drill bit; and a bit changer for changing a bit on at least one drill rod, the control device being configured to: receiving information regarding bit replacement; controlling the percussion device to strike the drill bit against the bottom of the formed borehole, thereby loosening the first threaded connection between the drill bit and the at least one drill rod; controlling the first feeding device to move the at least one drill rod and the drill bit out of the borehole; controlling the rotating device to remove the drill bit from the at least one drill rod; controlling the bit changer to change and replace the bit; and controlling the rotation device to attach the at least one drill rod to the drill bit through the first threaded connection.

This has the following advantages: the bit change operation of the rock drilling unit may be performed automatically. The first feeding means, the rotating means, the percussion means and the drill bit changer are controlled by a control unit so that the drill bit is automatically changed in a safe manner. Drill bits that may be heavy, sharp and/or inconvenient to hold and handle may be handled completely by means of instructions from the control device. The bit change operation is performed by the control means and may be based on information received from the sensors and from empirical data. The control device may be configured to initiate a replacement of the drill bit based on operational data of the drilling rig and the drill bit connected to the drilling rig. Thus, the bit change operation may be automatically initiated.

It should be understood that all examples described for method aspects of the disclosure performed by the control device also apply to the rock drilling unit, rock drilling rig and control device aspects of the disclosure. That is, the control device may be configured to perform any of the steps of the methods according to the various examples described above. Thus, according to the following aspects, the control device may be configured to perform the method steps according to the corresponding examples described above.

According to an aspect, the control device may thus be configured to control the second feeding device of the rock drilling unit to move the support device to a position where the support device abuts the drill bit. According to another aspect, the control device may be configured to control the gripping element of the rod handling system to grip at least one drill rod connected to the rotating device; and a second threaded connection configured to control the rotation device to tighten the at least one drill rod with the rotation device. According to another aspect, the received information about replacing the drill bit is based on the drilling conditions of the drill bit. According to another aspect, a bit changer for changing and replacing a drill bit is controlled by: the drill bit is moved from the drilling centre axis to the drill bit storage by means of the gripper arm, and subsequently a new drill bit is taken out of the drill bit storage and moved to the drilling centre axis.

The control means may be implemented as a separate entity or distributed among two or more physical entities. The control means may comprise one or more computers. Thus, the control device may be implemented or embodied by a control device comprising a processor and a memory, the memory comprising instructions which, when executed by the processor, cause the control device to perform the methods disclosed herein.

Furthermore, the present disclosure relates to a rock drilling unit comprising: a drill bit configured to be connected to at least one drill rod by a first threaded connection; a first feeding device for feeding at least one drill rod and a drill bit in an axial direction; a rotation device configured to generate a rotational movement of the at least one drill rod and the drill bit; a percussion device for providing percussion pulses on at least one drill rod and drill bit; and a drill bit changer for changing a drill bit on at least one drill rod, wherein the rock drilling unit comprises at least one control device as disclosed herein.

The rock drilling unit may comprise an elongated frame or beam on which the first feeding device, the rotation device and the percussion device are arranged. The rock drilling unit may be arranged on and connected to the vehicle by means of a boom, so that the rock drilling unit may be arranged in different positions in relation to the vehicle and the rock to be drilled. The rock drilling unit, the boom and the vehicle together form a rock drilling rig. The drilling unit may be configured for vertical drilling, which is considered to be completely vertical or to some extent deviated from the vertical. Thus, the drilling unit may be tiltable and drillable in an angled direction in the range of about 0 ° to about 95 ° relative to a vertical line without departing from the scope of the present disclosure. In a rock drilling machine, such a rock drilling unit configured for vertical drilling or drilling in an angled direction in the range of about 0 ° to about 95 ° with respect to the vertical line may be configured as a top hammer drill.

The drilling unit may also be provided with a bit changer, which assists in the automatic changing of the drill bit. The drill bit changer may comprise a drill bit storage arranged adjacent and parallel to the drilling central axis of the rock drilling unit and arranged to hold a plurality of drill bits and move the drill bits between a storage position comprised by the drill bit storage and a swap position. The drill bit storage means may have the shape of a cylindrical drum, wherein the movement between inner positions within the drill bit storage means may be performed by rotation of such cylindrical storage means or by means of rotation of inner parts of the cylindrical storage means. The drill bit storage device may of course have other designs without departing from the scope of the disclosure herein.

According to one aspect, a drill bit changer comprises a drill bit storage for drill bits and a gripper arm for moving the drill bits between the drill bit storage and a drilling centre axis.

The drill bit storage device may comprise at least one drill bit sensor arranged to monitor drill bits located in the position of the drill bit storage device. Thus, the control device may be provided with information not only about the current drilling operation, but also about the drilling operation to be performed at a later point in time. Since the drill bit storage device can hold a plurality of drill bits, the control device can monitor in a quick and simple manner how many drill bits are present in the device, wherein the planning of the drilling operation becomes faster and more efficient. The operator may also receive information from the control device as to how many bits are present in the device.

The control means may also be arranged to determine an operating condition of the drill bit based on the operating data of the drill bit, and the control means is arranged to provide a signal to the user interface when the drill bit needs to be replaced. Thus, the control device may assist in continuous monitoring of multiple drill bits, which may be used to maximize the use of each drill bit in the system. The control means may estimate the operational state of the drill bit on the basis of incoming operational data associated with other uses of said drill bit in the drilling operation for drilling. The operating conditions may be determined by the control device and provided to the operator before an upcoming bit change operation is required.

The drill bit storage device may include an enclosed protective housing. The housing may comprise at least a first door arranged at the exchange position, which may be arranged to be selectively opened and closed depending on the bit exchange operation performed. This will result in the protection of the drill bits stored in the bit storage from dust, dirt, oil or debris or the like which may be common at the drilling site. Protecting the stored drill bits in this manner increases the life of the drill bits and ensures that the drill bits are in a good shape and condition when the drill bits are extracted from the drill bit storage for use in a drilling operation.

A first door of the housing may be coupled to the clamp arm, wherein the first door automatically opens and closes in accordance with movement of the clamp arm. This will simplify the operation of the first door, since the operation of the first door can be performed fully automatically in connection with the gripper arm. Since the first door should normally only be opened when a bit change operation is performed, during such an operation the opening and closing of said first door can be synchronized with and controlled by the movement of the gripping arm during the movement of said first door in a reliable and efficient manner.

Furthermore, the present disclosure relates to a rock drilling rig comprising a rock drilling unit as disclosed herein.

The rock drilling rig comprises a rock drilling unit as disclosed herein. Furthermore, the rock drilling rig may also comprise a drilling platform, such as a vehicle. Connecting the rock drilling unit to the vehicle results in that the rock drilling rig can easily be moved to different places and different positions during the drilling operation. The rock drilling unit may be arranged on and connected to the vehicle by means of a boom, so that the rock drilling unit may be arranged in different positions in relation to the vehicle and the rock to be drilled.

According to an aspect, the rock drilling mechanism is caused to drill vertically or in an angled direction in the range of about 0 ° to about 95 ° with respect to the vertical.

The drilling rig may comprise a plurality of drill rods which are interchangeable, wherein the drill bit may be arranged at an end section of the end drill rod. The drill bit may be attached to the end section by means of a threaded connection. The rock drilling mechanism is configured for vertical drilling. However, the rock drilling machine may also be configured to drill in a direction deviating from vertical drilling. Such rock drills may be configured to drill in an angled direction in the range of about 0 ° to about 95 ° relative to the vertical.

The drilling machine may be a top hammer drilling machine. This has the following advantages: a conventional drilling machine may be provided with a bit changer for at least semi-automatic changing of a drill bit according to the present disclosure. Thus, a commonly used top hammer drill may be provided with a reliable and safe system for replacing the drill bit of the drill. Thus, an efficient and reliable drilling machine is provided, which provides a safe and convenient working environment by means of a system arranged on the drilling machine, since no manual exchange of the drill bit is required.

The disclosure will now be further explained with reference to the accompanying drawings.

Fig. 1 shows a rock drilling machine 5 according to an example in a perspective view. The rock drilling rig 5 comprises a rock drilling unit 8, which rock drilling unit 8 may comprise an elongated frame or beam 2. The rock drilling unit 8 may be arranged on the vehicle 6 by means of the boom 4 and connected to the vehicle 6, so that the rock drilling unit 8 may be arranged in different positions in relation to the vehicle 6 and the rock to be drilled. The rock drilling unit 8, the boom 4 and the vehicle 6 together form a rock drilling rig 5. The drilling rig 5 is configured for vertical drilling, which will be considered to be completely vertical or to some extent deviated from the vertical. Thus, the drilling rig 5 may be able to tilt and drill in an angled direction in the range of about 0 ° to about 95 ° relative to the vertical without departing from the scope of the present disclosure. The drilling rig 5 may comprise a plurality of interchangeable drill rods 7 (fig. 2), which plurality of drill rods 7 is arranged to form a drill string within a rock drilling unit 8 of the drilling rig 5. Each drill rod 7 comprises a thread which provides the option of connecting additional drill rods 7 as the drilled borehole 50 (fig. 2) becomes deeper. The drill bit 3 is then arranged at an end section of the end drill rod 7, wherein said drill bit 3 can be attached to the end section by means of a first threaded connection 40.

The drilling rig 5 may further comprise a support device 9, such as a lower support device, which support device 9 may be arranged at a lower part of the rock drilling unit 8 and arranged for supporting and/or holding/clamping the drill bit 3 or the drill rod 7, which support device 9 may be used for maintenance and/or assembling/disassembling these components. Furthermore, the support device 9 can guide the drill rod 7.

The drilling rig 5 shown in fig. 1 may also comprise a bit changer 1 for automatic or at least semi-automatic changing of the drill bit 3. The bit changer 1 is arranged close to the ground level and in parallel with the drilling centre axis 15 of the drilling unit 8. The term "drilling centre axis 15" may be considered as a centre line of a drill hole 50 (fig. 2) drilled by means of the drilling rig 5. The bit changer 1 is thus arranged to follow alignment with the drilling centre axis 15 when in use. If the rock drilling unit 8 is tilted to an angle, the drill bit changer 1 and the entry means of the drill bit changer 1 may also be tilted in this way together with the drilling central axis 15 and the drilling unit 8.

Figure 2 schematically illustrates a side view of a rock drilling unit 8 according to an example. The drill bit 3 is configured to be connected to the drill rod 7 by a first threaded connection 40. The rock drilling unit 8 comprises a first feeding device 42 configured for feeding the at least one drill rod 7 and the drill bit 3 in the axial direction. The rotation device 44 is configured to generate a rotational movement of the at least one drill rod 7 and the drill bit 3. The percussion device 46 is configured for providing impact pulses on at least one drill rod 7 and drill bit 3. The drill bit changer 1 is arranged on a rock drilling unit 8 for changing a drill bit 3 on a drill rod 7. The rotating device 44 and the impacting device 44 are arranged on the first feeding device 42. The rotating device 44 and the impact device 44 are configured to be displaced by means of the first feeding device 42. The first feeding means 42 is arranged on the elongated frame or beam 2. The first feeding device 42 is configured for feeding the drill rod 7 and the drill bit 3 in an axial direction both during the drilling operation and during the replacement of the drill bit 3. The first feed device 42 may be driven axially by means of a hydraulic or pneumatic actuator 10 relative to the rock drilling unit 8 and in the direction of the drilling central axis 15. The control device 100 is connected to the first feeding device 42, the rotating device 44, the impact device 46 and the drill bit changer 1. The control device 100 may be connected to a sensor 11, the sensor 11 being arranged on the rock drilling unit 8 or at a component connected to the rock drilling unit 8. The control device 100 may receive information from the memory 12 storing operational data.

The control device 100 is configured to receive information about the replacement of the drill bit 3; configured to control the percussion device 46 to strike the drill bit 3 against the bottom 48 of the formed borehole 50, thereby loosening the first threaded connection 40 between the drill bit 3 and the at least one drill rod 7; configured to control the first feeding device 42 to move the at least one drill rod 7 and the drill bit 3 out of the borehole 50; configured to control the rotating device 44 to remove the drill bit 3 from the at least one drill rod 7; configured to control a bit changer to change and replace the drill bit 3; and to control the rotation device 44 to attach the at least one drill rod 7 to the drill bit 3 through the first threaded connection 40.

Furthermore, the control device 100 is configured to control the second feeding device 52 such that the support device 9 is moved to a position where the support device 9 abuts the drill 3. The second feed device 52 may be driven axially relative to the rock drilling unit 8 and in the direction of the drilling central axis 15 by means of a hydraulic or pneumatic actuator. The control device 100 is connected to the second feeding device 52. The support device 9 is connected to the control device 100. The control device 100 is further configured to control the gripping element 54 of the rod handling system 56 to grip at least one drill rod 7 connected to the rotating device 44; and is configured to control the rotation device 44 to tighten the second threaded connection 58 between the at least one drill rod 7 and the rotation device 44. The rod handling system 56 comprises a magazine 60 of drill rods 7. The control device 100 is connected to the rod handling system 56. The bit changer 1 for changing and replacing the drill bit 3 is controlled by: the drill bits 3 are moved from the drilling central axis 15 to the drill bit storage 13 by means of the gripper arms 21, and thereafter new drill bits 3 are retrieved from the drill bit storage 13 and the new drill bits 3 are moved to the drilling central axis 15.

Fig. 3 illustrates a perspective view of the drill bit changer 1 according to an example, wherein also the parts of the drilling unit 8 where the drill bit changer 1 is arranged are shown in the figure. The drilling unit 8 may be a drilling unit 8 as shown in fig. 1 and 2 or a similar drilling unit, wherein the drilling unit 8 may be configured for vertical drilling or drilling in an angled direction in the range of about 0 ° to about 95 ° with respect to the vertical line. The drilling unit 8 may comprise an interchangeable magazine 60 of a plurality of drill rods 7. The drilling unit 8 may also comprise a lower support 9. The drilling unit 8 may further comprise an additional support element 14, which additional support element 14 is configured for loosening the threaded connection 16 (fig. 2) of the drill rod 7. The additional support element 14 of the drilling unit 8 may comprise two hydraulically controlled clamping devices 27, which two hydraulically controlled clamping devices 27 are arranged circumferentially around the drilling centre axis 15 and at separate positions along the drilling centre axis 15.

The bit changer 1 with the bit storage 13 may be arranged adjacent and parallel to the drilling central axis 15 of the drilling unit 8 and arranged to hold a plurality of drill bits 3 and move the drill bits 3 between a storage position 17 and an exchange position 19 comprised by the bit storage 13. The drill bit storage means 13 may have a cylindrical drum shape, wherein the movement between the

inner positions

17, 19 within the drill bit storage means 13 may be performed by such rotation of the cylindrical storage means 13 or by means of rotation of the inner parts of the cylindrical storage means 13. Each storage location 17 may hold one drill bit 3, which drill bit 3 may be a drill bit 3 ready for use or a drill bit 3 used in a previous drilling operation. The exchange location 19 may be a single location within the storage 13 from which the drill bits 3 may be removed or positioned, wherein the internal movement of the storage 13 may be used to position the desired slot for holding a particular drill bit 3 at the exchange location 19. The gripper arm 21 of the bit changer 1 may further comprise gripping means 23 configured for selectively gripping the drill bit 3. The clamping arm 21 is arranged to move the clamping means 23 between the exchange position 19 and the drilling centre axis 15 of the drilling unit 8. As shown in fig. 3, the clamp arm 21 and the clamp device 23 may be hydraulically controlled, wherein the movement and clamping of the clamp arm 21 and the clamp device 23 may be applied with high precision and apply a large force to the function. Furthermore, since the clamp arm 21 only needs to be moved to a single position 19 within the bit storage 13, the movement of the clamp arm 21 can be performed by means of a pivoting movement, which reduces the complexity of the design of the clamp arm 21 and the clamp arm 21.

The gripping means 23 may further comprise a sensor 11 (fig. 2) arranged to monitor the operating state of the gripping means 23 and the pressure applied towards the drill bit 3. Such a sensor 11 can easily be arranged in or at the hydraulics of the gripping means 23, since the internal pressure of the hydraulic cylinder controlling the gripping movement of the gripping means 23 is directly related to when the gripping means 23 engages an object. Thus, the sensor 11 may be used to ensure that the gripping means 23 always provides the same amount of gripping force to an object (such as a drill bit) regardless of the size of the object.

The gripper arm 21 may further comprise a sensor 11 arranged to monitor the movement of the gripper arm 21. Like the sensor 11 for the gripping means 23, such a sensor 11 may be a sensor 11 arranged in or at the hydraulic device for controlling the gripping arm 21. Other types of sensors 11, such as IR sensors or the like, may of course be used without departing from the scope of the present disclosure. By monitoring the movement of the gripping arm 21, it should be noted that such monitoring may also be used to obtain position information relating to the position of the gripping arm 21 at any given point in time and thus also relating to the position of the gripping means 23 at any given point in time. Thus, the movement and positioning of the gripper arm 21 and the deflection of the gripper arm 21 can be monitored with high accuracy and reliability. If, for example, the gripper arm 21 moves the drill bit 3 away from the drilling centre axis 15 and the drill bit 3 somehow seizes in the predetermined path of the drill bit 3, the internal pressure of the hydraulic device will increase at an unexpected point in time and the sensor 11 can warn the bit changer 1 of an accident situation.

The bit changer 1 is connected to a control unit 100 (fig. 2), the control unit 100 being arranged to receive inputs from the sensor 11 and the drilling unit 8 and to control the movements of the gripping arm 21, the gripping device 23, the bit storage 13 and the additional support element 14 of the drilling unit 8. The control unit 100 may be arranged in the drill bit changer 1 or at a remote location, such as for example in an operating room of the drilling rig 5. The control unit 100 may be coupled to the sensor 11, the bit changer 1 and the drilling unit 8 by means of a wired interface or by means of a wireless interface according to the prior art.

By connecting the control unit 100 not only to the components of the bit changer 1 and the bit changer 1, but also to the drilling unit 8 and the components of the drilling unit 8, the control unit 100 is able to allow the drilling unit 8 and the bit changer 1 to interact and cooperate, which provides for a more efficient operation to be performed by the bit changer 1. Furthermore, since the control unit 100 can control and control machinery such as the additional support element 14 of the drilling unit 8, the bit changer 1 itself requires less complex machinery, which reduces the manufacturing costs of the bit changer 1.

The drill bit storage means 13 may further comprise at least one drill bit sensor 11 arranged to monitor the drill bits 3 located in

positions

17, 19 of the drill bit storage means 13. Such at least one sensor 11 may be an optical sensor or a pressure sensor or the like, such at least one sensor 11 may be arranged to monitor whether the drill bit 3 is located in a

specific position

17, 19 or, in case a plurality of such sensors 11 are arranged, to monitor whether the drill bit 3 is located in a plurality of

positions

17, 19. Such a sensor 11 may also be a more complex sensor device arranged not only for monitoring the positioning within the storage 13, but also for analyzing and evaluating the drill bit 3 positioned in the storage 13. Such sensor means may scan the surface of the drill bit 3 and compare the surface of the drill bit 3 with a predetermined surface of a well-functioning drill bit 3, wherein the control unit 100 may provide information to the operator of the drilling unit 8 about the status of the drill bit 3 positioned in the storage means 13. Whereby a faulty drill bit 3 can be discovered and replaced to extend the uptime of the operation of such a drilling unit 8.

The control unit 100 may be configured to initiate an automatic or at least semi-automatic replacement of a drill bit 3 based on the drilling unit 8 and the operational data of the drill bit 3 connected to the drilling unit 8. Such operational data may be data including any one or combination of the following: drilling time spent, drilling time spent since last maintenance, expected time remaining until replacement is needed, meters drilled since last maintenance, or others. Such operational data may relate to the drilling unit 8, each drill bit 3 arranged in the drill bit changer 1, or both the drilling unit 8 and each drill bit 3 arranged in the drill bit changer 1. By taking such operational data into account and by using available drilling schemes, the control unit 100 may thus automatically initiate a bit change operation between the drilling of the drill hole 50 (fig. 2) if it is determined that the current drill bit 3 will be inoperable for all of the next hole 50 to be drilled. Since there is no need to perform an inspection of the drill bit 3 between holes 50 to be drilled, a lot of wasted time can be saved from a drilling solution comprising a plurality of holes 50.

The control unit 100 may also be arranged to determine the operational condition of the drill bit 3 based on operational data of the drill bit 3, and the control unit 100 is arranged to provide a signal to the interface when the drill bit needs to be replaced. If certain operational data, such as previously spent drilling time, type of material used for a particular drill bit 3, etc., is known in advance, and said drill bit 3 is used for drilling, the control unit may then monitor and update such operational data in order to provide and update the operational conditions for said drill bit 3. If it is estimated, for example, that the drill bit 3 is able to drill a certain amount of time in a certain type of material, the control unit 100 may increase the operating time for said drill bit 3 and monitor the use of said drill bit 3 over time. This data can then be stored in a memory and tracked for each specific drill bit 3 in the drill bit changer 1, wherein the drill bits 3 positioned in the storage positions 17 of the drill bit storage 13 can be monitored according to their individual operating conditions. Such information may then be sent to a user interface or the like in order to display the operating conditions of all available drill bits 3, wherein the information may be used by the operator of the drilling rig 5 to better plan future drilling operations. The control unit 100 may also plan a drilling operation in connection with the provided drilling plan, wherein a suitable drill bit 3 is moved to the exchange location 19 when a hole is to be drilled, for which the operating conditions of said drill bit 3 are considered suitable. By allowing the control unit 100 to plan the drilling operation and automatically initiate a bit change operation in this way, a lot of time can be saved and the drill bit 3 can be used for the combined maximum capacity of the drill bit 3.

Fig. 4 schematically illustrates a perspective view of a gripper arm of the drill bit changer 1 according to an example. The gripping arm 21 of the bit changer 1 comprises gripping means 23 configured for selectively gripping the drill bit 3. In fig. 4, the clamping arm 21 is moved to the drilling centre axis 15 of the drilling unit 8 and above the support 9. The support device 9 may be a lower support device of the rock drilling unit 8 arranged for supporting and/or holding/clamping the drill bit 3 or the drill rod 7. Thus, the drill bit 3 may be supported by the support means 9 such that the drill bit 3 rests on the support means 9 or abuts the support means 9. Alternatively, the support means 9 is moved to a position where the support means 9 is able to clamp the drill bit 3. In case the drill bit 3 can be supported by the supporting means 9, the supporting means 9 should be arranged below the drill bit 3 in order to support the drill bit 3 from below when the drill bit 3 is held by the clamping device 23. An advantage of moving the support device 9 to a position where the support device 9 supports the drill bit 3 from below is that a variety of drill bits 3 having different designs may be exchanged in the rock drilling unit 8. Since the type and design of the drill bit 3 may vary depending on the type of drilling machine 5, the gripping means 23 may not be able to hold the drill bit 3 without the bearing arrangement 9, which may thus be provided by the bearing arrangement 9. By means of such a movement of the clamping means 23 and the bearing arrangement 9, the replacement of the drill bit 3 can thus increase its use and be used for various types of drilling units 8.

Fig. 5 shows a flow diagram of a method according to an example. The method is performed by the control device 100 for replacing a drill bit in the rock drilling unit 8. The method thus relates to control of replacement of the drill bit 3 in the rock drilling unit 8 disclosed in fig. 1-4. The rock drilling unit 8 comprises: a first feeding device 42, the first feeding device 42 being adapted to feed at least one drill rod 7 and a drill bit 3 in an axial direction; a rotation device 44, the rotation device 44 being configured to generate a rotational movement of the at least one drill rod 7 and the drill bit 3; a percussion device 46, the percussion device 46 being adapted to provide percussion pulses on at least one drill rod 7 and drill bit 3; and a drill bit changer 1, the drill bit changer 1 being adapted to change a drill bit 3 on at least one drill rod 7.

The method comprises the following steps: receiving information on replacement of the drill bit 3 from sl0 l; controlling sl02 percussion device 46 to punch drill bit 3 against bottom 48 of formed borehole 50, thereby loosening first threaded connection 40 between drill bit 3 and at least one drill rod 7; controlling the sl03 first feeding means 42 to move the at least one drill rod 7 and the drill bit 3 out of the borehole 50; controlling sl04 to rotate device 44 to remove drill bit 3 from at least one drill rod 7; controlling sl05 bit changer 1 to change and replace bit 3; and controlling the sl06 rotation means 44 to attach the at least one drill rod 7 to the drill bit 3 through the first threaded connection 40.

Fig. 6 shows a flow diagram of a method according to an example. The method is performed by a control device 100 for replacing a drill bit 3 in a rock drilling unit 8. The method thus relates to control of replacement of the drill bit 3 in the rock drilling unit 8 disclosed in fig. 1-4. The method comprises the following steps: receiving information on replacement of the drill bit 3 from sl0 l; controlling sl02 percussion device 46 to punch drill bit 3 against bottom 48 of formed borehole 50, thereby loosening first threaded connection 40 between drill bit 3 and at least one drill rod 7; controlling the sl03 first feeding means 42 to move the at least one drill rod 7 and the drill bit 3 out of the borehole 50; controlling sl04 to rotate device 44 to remove drill bit 3 from at least one drill pipe 7; controlling sl05 bit changer 1 to change and replace bit 3; and controlling the sl06 rotation means 44 to attach the at least one drill rod 7 to the drill bit 3 through the first threaded connection 40.

After controlling the sl05 drill bit changer 1 to change the drill bit 3, and before controlling the sl06 rotation means 44 to attach the at least one drill rod 7 to the drill bit 3 through the first threaded connection 40, the method further comprises: the second feed device 52 of sl07 rock drilling unit 8 is controlled to move the support device 9 to a position where the support device 9 abuts the drill bit 3.

After controlling the sl03 first feeding means 42 to move the at least one drill rod 7 and the drill bit 3 out of the borehole 50, and before controlling the sl04 rotating means 44 to remove the drill bit 3 from the at least one drill rod 7, the method further comprises: controlling the gripping element 54 of the sl08 rod handling system 56 to grip at least one drill rod 7 connected to the rotating device 44; and controlling the sl09 rotating device 44 to tighten the second threaded connection 58 between the at least one drill pipe 7 and the rotating device 44.

Fig. 7 is a schematic diagram of an arrangement of apparatus 500. The control device 100 described with reference to fig. 2 and 3 may include a device 500 in a scheme. The apparatus 500 comprises a non-volatile memory 520, a data processing unit 510 and a read/write memory 550. The non-volatile memory 520 has a first storage element 530, in which first storage element 530 a computer program, for example an operating system, is stored for controlling the functions of the apparatus 500. The device 500 also includes a bus controller, a serial communication port, an I/O device, an A/D converter, a time and date input and transmission unit, an event counter, and an interrupt controller (not depicted). The non-volatile memory 520 also has a second storage element 540.

A computer program P is provided which comprises routines for controlling the rock drilling rig 5. The program P may be stored in the memory 560 and/or the read/write memory 550 in an executable form or in a compressed form.

In case the data processing unit 510 is described as performing a specific function, this means that the data processing unit 510 implements a specific part of the program stored in the memory 560 or a specific part of the program stored in the read/write memory 550.

The data processing device 510 may communicate with a data port 599 via a data bus 515. The non-volatile memory 520 is intended to communicate with the data-processing unit 510 via a data bus 512. The separate memory 560 is intended to communicate with the data-processing unit 510 via a data bus 511. The read/write memory 550 is adapted for communication with the data-processing unit 510 via a data bus 514.

When data is received on the data port 599, the data is temporarily stored in the second storage element 540. When the received input data has been temporarily stored, the data processing unit 510 is ready to implement the code execution as described above.

Parts of the methods described herein may be implemented by the apparatus 500 by means of the data processing unit 510, the data processing unit 510 running a program stored in the memory 560 or the read/write memory 550. The methods described herein are performed when the apparatus 500 runs a program.

The foregoing description of embodiments has been presented for purposes of illustration and description. The foregoing description is not intended to be exhaustive or to limit the embodiments to the precise form described. Many modifications and variations will be apparent to practitioners skilled in the art. The embodiments were chosen and described in order to best explain the principles and the practical application, and to thereby enable others skilled in the art to understand the invention for various embodiments with various modifications as are suited to the particular use contemplated. The components and features described above may be combined between the different embodiments described within the framework of the present disclosure.

Claims

1. A method performed by a control device (100) for replacing a drill bit (3) in a rock drilling unit (8), the drill bit (3) being configured to be connected to at least one drill rod (7) by a first threaded connection (40), the rock drilling unit (8) comprising:

-first feeding means (42), said first feeding means (42) being adapted to feed said at least one drill rod (7) and said drill head (3) in an axial direction;

-a rotation device (44), said rotation device (44) being configured to generate a rotational movement of said at least one drill rod (7) and of said drill bit (3);

a percussion device (46), the percussion device (46) being adapted to provide percussion pulses on the at least one drill rod (7) and the drill bit (3); and

a drill bit changer (1), the drill bit changer (1) being for changing a drill bit (3) on the at least one drill rod (7), the method comprising:

receiving (s101) information about replacing the drill bit (3);

-controlling (sl02) the percussion device (46) to punch the drill bit (3) against the bottom (48) of the formed borehole (50) so as to loosen the first threaded connection (40) between the drill bit (3) and the at least one drill rod (7);

-controlling (sl03) the first feeding means (42) to move the at least one drill rod (7) and the drill bit (3) out of the drill hole (50);

controlling (sl04) the rotating means (44) to remove the drill bit (3) from the at least one drill rod (7);

controlling (sl05) the bit changer (1) to change and replace the bit (3); and

controlling (sl06) the rotating means (44) to attach the at least one drill rod (7) to the drill bit (3) through the first threaded connection (40).

2. A method according to claim 1, wherein after controlling (sl05) the drill bit changer (1) to change the drill bit (3) and before controlling (sl06) the rotation means (44) to attach the at least one drill rod (7) to the drill bit (3) through the first threaded connection (40), the method further comprises:

controlling (sl07) a second feed device (52) of the rock drilling unit (8) to move a support device (9) to a position where the support device (9) abuts the drill bit (3).

3. Method according to any one of claims 1 and 2, wherein after controlling (sl03) the first feeding means (42) to move the at least one drill rod (7) and the drill bit (3) out of the borehole (50), and before controlling (sl04) the rotating means (44) to remove the drill bit (3) from the at least one drill rod (7), the method further comprises:

controlling (sl08) a clamping element (54) of a rod handling system (56) to clamp the at least one drill rod (7) connected to the rotating device (44); and

controlling (sl09) the rotation device (44) to tighten a second threaded connection (58) between the at least one drill rod (7) and the rotation device (44).

4. The method according to any one of the preceding claims, wherein receiving (s101) information about replacing the drill bit (3) is based on drilling conditions of the drill bit (3).

5. Method according to any of the preceding claims, wherein controlling (sl05) the bit changer (1) to change and replace the drill bit (3) comprises: -moving the drill bit (3) from the drilling centre axis (15) to a drill bit storage (13) by means of a gripper arm (21), and subsequently taking a new drill bit (3) from the drill bit storage (13) and moving the new drill bit (3) to the drilling centre axis (15).

6. A computer program (P) comprising instructions which, when the program is executed by a computer (100; 500), cause the computer (100; 500) to carry out the method according to any one of the preceding claims.

7. A computer-readable medium comprising instructions that, when executed by a computer (100; 500), cause the computer (100; 500) to carry out the method according to any one of claims 1 to 5.

8. A control apparatus (100) of a rock drilling unit (8), the rock drilling unit (8) comprising:

a drill bit (3), the drill bit (3) being configured to be connected to at least one drill rod (7) by a first threaded connection (40);

-a rotation device (44), said rotation device (44) being configured to generate a rotation movement of said at least one drill rod (7) and of said drill bit (3);

a bit changer for changing a drill bit (3) on the at least one drill rod (7), the control device (100) being configured to:

receiving information about replacing the drill bit (3);

-controlling the percussion device (46) to strike the drill bit (3) against the bottom (48) of the formed drill hole (50) so as to loosen the first threaded connection (40) between the drill bit (3) and the at least one drill rod (7);

-controlling the first feeding means (42) to move the at least one drill rod (7) and the drill bit (3) out of the borehole (50);

-controlling the rotation device (44) to remove the drill bit (3) from the at least one drill rod (7);

-controlling the bit changer to change and replace the drill bit (3); and

-controlling the rotation device (44) to attach the at least one drill rod (7) to the drill bit (3) through the first threaded connection (40).

9. A control device (100) according to claim 8, wherein the control device (100) is configured to control a second feed device (52) of the rock drilling unit (8) to move a support device (9) to a position where the support device (9) abuts the drill bit (3).

10. The control device (100) according to any one of claims 8 and 9, wherein the control device (100) is configured to control a gripping element of a rod handling system to grip the at least one drill rod (7) connected to the rotating device (44); and configured to control the rotation device (44) to tighten a second threaded connection (58) between the at least one drill rod (7) and the rotation device (44).

11. The control device (100) according to any one of claims 8 to 10, wherein the received information about replacing the drill bit (3) is based on drilling conditions of the drill bit (3).

12. Control device (100) according to any one of claims 8 to 11, wherein the bit changer for changing and replacing the drill bit (3) is controlled by: -moving the drill bit (3) from the drilling centre axis (15) to a drill bit storage (13) by means of a gripper arm (21), and subsequently taking a new drill bit (3) from the drill bit storage (13) and moving the new drill bit (3) to the drilling centre axis (15).

13. A rock drilling unit (8) comprising:

-first feeding means (42), said first feeding means (42) being intended to feed said at least one drill rod (7) and said drill bit (3) in an axial direction;

a drill bit changer (1) for changing a drill bit (3) on the at least one drill rod (7), wherein the rock drilling unit (8) comprises at least one control device (100) according to any one of claims 8 to 12.

14. The rock drilling unit (8) as claimed in claim 13, wherein the drill bit changer (1) comprises a drill bit storage (13) for drill bits (3) and a gripper arm (21) for moving the drill bits (3) between the drill bit storage (13) and a drilling centre axis (15).

15. A rock drilling rig (5) comprising a rock drilling unit (8) according to any one of claims 13 to 14.

16. The rock drilling machine (5) as claimed in claim 15, wherein the rock drilling machine (5) is configured for vertical drilling or drilling in an angled direction in the range of about 0 ° to about 95 ° relative to a vertical line.