EP4431695B1

EP4431695B1 - Shank sleeve assembly, rock drilling machine and method

Info

Publication number: EP4431695B1
Application number: EP23162685.4A
Authority: EP
Inventors: Lars Kandelin; Mikko HÄMÄLÄINEN; Timo Kela; Esa LÄÄKKÖLÄ
Original assignee: Sandvik Mining and Construction Oy
Current assignee: Sandvik Mining and Construction Oy
Priority date: 2023-03-17
Filing date: 2023-03-17
Publication date: 2025-12-10
Anticipated expiration: 2043-03-17
Also published as: FI4431695T3; CL2025002747A1; KR20250137728A; PE20252619A1; EP4431695A1; AU2024241288A1; CN120813752A; MX2025010914A; WO2024193943A1

Description

Background of the invention

The invention relates to a shank sleeve assembly of a rock drilling machine and comprising a split sleeve surrounding a shank adapter.
The invention further relates to a rock drilling machine and to a method of providing a shank bushing with two-piece configuration.
The field of the invention is defined more specifically in the preambles of the independent claims.
In mines and at other work sites different type of rock drilling rigs are used. The rock drilling rigs are provided with one or more booms and rock drilling machines are arranged at distal ends of the booms. The rock drilling machine comprises an impact device provided with an impact piston which is configured to provide a drilling tool with impact pulses via a shank adapter. The shank adapter is configured to transmit impact pulses and torque from the rock drilling machine to a drilling tool. The shank adapter can be supported axially by means of a shank bushing. Depending on construction of the rock drilling machine and dimensions of the shank adapter there may be a need to use a split shank bushing to allow the mounting and dismounting. One known shank adapter is disclosed in the patent publication US 3 259 403 A . However, in known solutions some disadvantages have been detected especially regarding wear of the shank bushing.

Brief description of the invention

An object of the invention is to provide a novel and improved shank sleeve assembly, rock drilling machine, and method.
The shank sleeve assembly according to the invention is characterized by the characterizing features of the first independent apparatus claim.
The rock drilling machine according to the invention is characterized by the characterizing features of the second independent apparatus claim.
The method according to the invention is characterized by the characterizing features of the independent method claim.
An idea of the disclosed solution is that a two-piece shank bushing is assembled to surround a shank adapter of a rock drilling machine, and the shank bushing is surrounded by means of a bearing bushing. This arrangement allows rotation of the shank bushing.
In other words, the shank bushing has split structure comprising at least two compatible bushing components which are surrounded by means of a separate bearing bushing providing support for the bushing components.
An advantage of the disclosed solution is that the shank bushing having the split structure can be made rotatable when the bushing components are supported properly by means of the bearing bushing. Allowing the rotation for the shank bushing is beneficial because then wearing is distributed evenly on surfaces of the shank bushing components. The moving shank adapter does not direct the wearing continuously to same surface areas of the shank bushing and wearing of the shank adapter is also reduced. The proper support offered by the surrounding bearing bushing guaranties smooth rotation for the shank bushing components. Improved wear resisting properties mean longer operating life for the shank bushing and less maintenance work.
The bearing bushing comprises an inwardly facing shoulder at a first end part of the bearing bushing. The shank bushing comprises a first end facing towards drilling direction. Further, a face surface at the first end of the shank bushing is mountable against the shoulder of the bearing bushing. In other words, the components of the split shank bushing are supported axially against the shoulder of the bearing bushing and are thereby properly supported in the axial direction against a uniform surface of the shoulder.
According to an embodiment, the two-piece shank bushing is mounted rotatably in relation to the bearing bushing. In other words, the connection between the two-piece shank bushing and the surrounding bearing bushing allows rotation movement between them.
According to an embodiment, the shank sleeve assembly is without rotation surfaces between the shank bushing and the bearing bushing. However, on an outer surface of the bearing bushing are rotation surfaces for allowing rotation of the assembly. An advantage of this solution is that there are uniform surfaces without joints at the rotating connection of the assembly. Further, manufacturing, and dimensional accuracy of the two piece components are not critical since they are rotating.
According to an embodiment, between the two-piece shank bushing and the bearing bushing is a connection which allows only limited axial relative movement between them. In other words, relative rotation between the shank bushing and the bearing bushing is prevented but axial movement may occur. The connection may comprise for example splines or other form surfaces which transmit torque but allow the axial movement.
According to an embodiment, components of the two-piece shank bushing are both mounted immovably to the bearing bushing. The components of the shank bushing may be fastened to the bearing bushing by means of screw fastening, for example.
According to an embodiment, there is a clearance fit between the split shank bushing and the bearing bushing.
According to an embodiment, the assembly is supported to a flushing housing being part of a frame structure of a rock drilling machine. The flushing housing forms a space around a defined part of the shank adapter and allows feeding of flushing fluid via the space to a flushing fluid channel of the shank adapter.
According to an embodiment, the disclosed solution allows use of increased diameters of rotating joints of the assembly, which is beneficial for rigidity and wearing resisting properties.
According to an embodiment, the solution also allows use of shank adapters with shoulders i.e., shank adapters which implement a so called shoulder driven contact on threaded rock tool couplings.
In this document the bushings can also be called sleeves i.e., the bushings are longitudinal pieces with inner and outer circumferences.
According to an embodiment, the bearing bushing comprises rotation surfaces on its outer circumference and is allowed to be rotatably mounted. In other words, there may occur rotation between the split shank bushing and bearing bushing, and between the bearing bushing and a structure surrounding the bearing bushing. Thus, two rotation joints are provided. An advantage of this embodiment is that rotating movement in the shank sleeve assembly is divided for two rotation joints i.e., on inner and outer circumferences of the bearing bushing, whereby wearing can be reduced when compared to situation wherein only one rotation joint is implemented. When the rotation movement of the shank adapter is divided with two rotation joints, less rotation movement and less wearing is directed to one rotation joint.
According to an embodiment, the rotation surfaces of the bearing bushing comprise rotation symmetrical outer surfaces.
According to an embodiment, the bearing bushing has uniform non split configuration whereby it has solid structure capable for providing rigid support for the shank bushing with split configuration. The bearing bushing forms a case-like structure around the shank bushing.
According to an alternative embodiment, the bearing bushing is not a rotatable component but is instead supported to a surrounding frame part so that it does not move during the operation of the rock drilling machine. In this embodiment rotation occurs between the shank bushing and the inner surface of the bearing bushing.
According to an embodiment, the shank sleeve assembly further comprises a wearing bushing arrangeable to surround the bearing bushing. In other words, the assembly comprises three successive sleeve like components arranged to be one inside another, i.e., there are three separate nested sleeves around the shank adapter namely: the shank bushing, the bearing bushing, and the wearing bushing. The bearing bushing is supported indirectly via the wearing bushing to the frame. An advantage of this embodiment is that the wearing bushing is an easily changeable wearing piece which can be changed when needed. The wearing bushing provides protection for a frame surrounding the assembly. It is much easier and less expensive to change the wearing bushing than to change or repair the frame or change the bearing bushing. A further advantage of the separate wearing bushing is that it can be designed case by case and without basic limitations relating to the frame construction. Thereby material, shapes and other features can be selected more freely.
According to an embodiment, the assembly comprises totally four pieces including one-piece wearing bushing, one-piece bearing bushing and two halves of the split shank bushing.
According to an alternative embodiment, the assembly is without any separate wearing bushing. Then the frame is provided with a space for receiving the bearing bushing i.e., the bearing bushing is supported directly to the frame.
According to an embodiment, one end of the wearing bushing comprises a flange protruding inwardly and providing a supporting axial surface for the bearing bushing. In other words, the flange of the wearing bushing can serve as an axial limiting element and can partly define a space wherein the bearing bushing rotates.
According to an embodiment, the flange of the wearing bushing is configured to determine axial clearance for the bearing bushing. In case too great axial clearance occurs due to wear, it is possible to return the original clearance setting by changing the wearing bushing. Further, by selecting the wearing bushings with different dimensions, it is possible to affect to the axial clearance.
According to an embodiment, the first bushing component and the second bushing component of the shank bushing may be fastened to each other so that they form together one piece when in use. When the bushing components are assembled and fastened together, then the components do not expand radially away from each other during the use. This way designed clearances remain and the shank bushing operates in a designed manner.
According to an embodiment, the bushing components of the shank bushing are fastened to each other by means of screws or other fastening elements. An alternative is to provide the coupling surfaces of the components with shape locking elements or structures.
According to an embodiment, the solution may further comprise at least one sealing element, such as an O-ring arranged on an outer surface of the bearing bushing. The sealing element may be utilized for directing lubricating fluid for the assembly in a desired manner.
According to an embodiment, the mentioned at least one sealing element on the bearing bushing, such as an O-ring, may be arranged on an outer surface of the bearing bushing, and may be utilized for facilitating mounting of the assembly.
According to an embodiment, the disclosed solution also relates to a rock drilling machine comprising: a frame; an impact device for generating impact pulses; a shank adapter for receiving the impact pulses and transmitting them as stress waves to a drilling tool connectable to the shank adapter; a rotation device for turning the shank adapter around its longitudinal axis; and a shank sleeve assembly comprising a shank bushing with split configuration surrounding the shank adapter and configured to transmit axial forces between the frame and the shank adapter. Further, the shank sleeve assembly is in accordance with the features disclosed in this document.
According to an embodiment, the disclosed solution also relates to a method of providing a rock drilling machine with a rotating shank bushing. The method comprises: providing the shank bushing with two-piece configuration comprising a first bushing component and a second bushing component; and arranging the bushing components to surround a shank adapter of the rock drilling machine. The method further comprises surrounding the shank bushing by means of a separate bearing bushing and allowing the two-piece shank bushing to rotate around its longitudinal axis in relation to the bearing bushing.
According to an embodiment, the method further comprises supporting the bearing bushing rotationally in relation to a frame of the rock drilling machine.
According to an embodiment, the method further comprises supporting the bearing bushing to a frame of the rock drilling machine by means of a separate wearing bushing surrounding the bearing bushing.
According to an embodiment, a shoulder contact shank adapter is implemented.
According to an embodiment, an alternative bottom contact shank adapter is implemented. Then, a coupling head of the shank adapter comprises a coupling thread and is without a shoulder.
In this document the terms "split" and "split configuration" refer to a structure having non-uniform rim or circumference. The structure can be split or dismantled in radial direction into at least two parts or ring-like segments. Since the shank bushing has the two-part configuration, it can be mounted and removed in radial direction despite dimensions and shapes of the shank adapter.
The above disclosed embodiments may be combined in order to form suitable solutions having those of the above features that are needed.

Brief description of the figures

Some embodiments are described in more detail in the accompanying drawings, in which

Figure 1 is a schematic side view of a rock drilling rig for surface drilling,
Figure 2 is a schematic view of a hydraulic rock drilling machine,
Figure 3 is a schematic side view of a front part of a rock drilling machine,
Figure 4 is a schematic and cross-sectional side view of a front part of a rock drilling machine and a shank adapter provided with a shoulder,
Figure 5 is a schematic and cross-sectional detail C of a shank sleeve arrangement of Figure 4,
Figure 6 is a schematic and cross-sectional side view of a front end of a rock drilling machine provided with a shank sleeve arrangement mountable and demountable from a rear side direction,
Figure 7 is a schematic and cross-sectional detail D of a shank sleeve arrangement of Figure 6,
Figure 8 is a schematic view of a shank bushing having two-piece configuration,
Figure 9 is a schematic and cross-sectional side view of a front end of a rock drilling machine provided with a bottom contact type shank adaptor,
Figure 10 is a schematic and cross-sectional side view of a front end of a rock drilling machine provided with a shank sleeve arrangement with one supporting sleeve for a shank bushing, and
Figure 11 is a schematic and cross-sectional detail E of a shank sleeve arrangement of Figure 10.

For the sake of clarity, the figures show some embodiments of the disclosed solution in a simplified manner. In the figures, like reference numerals identify like elements.

Detailed description of some embodiments

Figure 1 shows a rock drilling rig 1 intended for surface drilling. The rock drilling rig 1 comprises a movable carrier 2 and at least one drilling boom 3 connected to the carrier 2. At a distal end portion of the drilling boom 3 is a drilling unit 4 provided with a feed beam 5 and a rock drilling machine 6 supported on it. A drilling tool 7 is connectable to the drilling machine 6. The rock drilling machine 6 comprises a shank adaptor 8 at a front end FE of the rock drilling machine 6 for connecting the drilling tool 7. The rock drilling machine 6 further comprises an impact device 9 and a rotating device 10. The rock drilling machine 6 may be moved towards a drilling direction A on the feed beam 5 by means of a feed device 11. During the drilling impact pulses are generated by means of the impact device to the rotating shank adapter 8 which transmits the impacts pulses and torque to the drilling tool 7. Flushing agent flow is conveyed through a hollow structure to the shank adapter 8 and all the way through the drilling tool 7 to a bottom of the drilled hole for flushing drilling cuttings away from the drilled hole.
Figure 2 discloses a rock drilling machine 6 comprising a body 12, an impact device 9, a rotating device 10 and a gear housing 13. Mounted at a front end FE of the body 12 are a flushing housing 14 and a shank adaptor 8. Flushing agent, such as water, is conveyed by means of a flushing channel 15 to the flushing housing 14 or flushing head. The flushing housing 14 comprises a frame 16 which is removably mountable to the gear housing 13.
The impact device 9 may comprise an impact piston for generating impact pulses to the shank adapter 8 in an impact direction. The rotation device 10 together with transmission means inside the gear housing 13 make the shank adapter 8 to rotate around its longitudinal axis.
Figure 3 discloses a front end FE of a rock drilling machine when being detached from a gear housing. The front end FE comprises a flushing housing 14 through which a shank adapter 8 is mounted. At a rear end of a frame 16 of the flushing housing 14 is a mounting surface 17 which can be mounted against matching mounting surface on the gear housing. The shank adapter 8 comprises splines 18 or corresponding transmission surfaces at its rear end portion. When the flushing housing 14 is mounted in place the splines 18 are in contact with gears of the gear housing. An impact surface 19 of the shank adapter 8 is configured to receive impact pulses from an impact device. At an opposite end of the shank adapter 8 there are connecting means 20 comprising connecting threads 21. In this case the shank adapter 8 is of shoulder contact type and comprises a shoulder 22 against which an end of a drilling tool is supported when being connected. The flushing housing 14 comprises a feed port 23 for feeding flushing fluid via a flushing space 24 and a flushing channel 25 of the shank adapter 8 to the drilling tool as it is shown by means of arrows in Figure 4.
Figure 4 discloses a shank sleeve assembly 26 mounted around the shank adapter 8 and comprising a shank bushing 27 provided with an inwardly protruding shoulder 28 for providing axial support for the shank adapter 8. The shank bushing 27 has two-piece configuration, which is disclosed in Figure 8. The shank bushing 27 has a first bushing component 27a and a second bushing component 27b both provided with coupling surfaces 29 connectable in radial direction against each other. Figure 4 and a detail C presented in Figure 5 show that the shank sleeve assembly 26 further comprises a bearing bushing 30 arrangeable to surround the two-piece shank bushing 27. The structure allows well supported rotation between the shank bushing 27 and the bearing bushing 30. The bearing bushing 30 comprises rotation surfaces 31 on its outer circumference. The shank sleeve assembly 26 further comprises a wearing bushing 32 arranged to surround the bearing bushing 30. At a rear end of the wearing bushing 32 is a flange 33 protruding inwardly and providing a supporting axial surface for the bearing bushing 30. A front end of the wearing bushing 32 is supported against an axial surface formed on a frame 16.
Figure 6 and a detail D in Figure 7 disclose a solution that differs from the one shown in previous Figures 4 and 5 in that there is no wearing bushing but instead the bearing bushing 30 is supported directly to the frame 16. A front end of the bearing bushing 30 is supported axially against a shoulder 34 formed in the frame and a rear end is supported by means of a locking element 35, such as a locking ring. Installation direction of the disclosed shank sleeve assembly 26 is from the rear end side, whereas in the solution disclosed in Figures 4 and 5 the installation of the shank sleeve 27 and the bearing bushing 30 is from the front end side.
Figures 5 and 7 further show that the bearing bushing 30 comprises an inwardly facing shoulder 36 at a first end part of the bearing bushing 30. The shank bushing 26 is supported against the shoulder 36.
Figure 9 discloses a solution that differs from the one shown in Figure 4 in that the shank adapter 8 is of different type and is without any shoulder. The shank sleeve arrangement 26 may be as it is disclosed in detail C in Figure 5.
Figure 10 discloses a solution that differs from the one shown in Figure 6 in that the shank adapter 8 is of different type and comprises a shoulder. Further, there is no separate locking element 35 for preventing axial movement of the bearing bushing in rearward direction but instead the bearing bushing 30 extends to a same level as the frame 16.
In the cross-sectional Figures 4, 6, 7, 9 and 10 it cannot be seen that the shank sleeve 27 has the split configuration. However, the split structure is shown in Figure 8. The components or halves 27a, 27b may be bolted together or may be connected to each other in any other ways, such as by means of shape locking, for example. The halves 27a, 27b define together an axial opening inside which the shank adapter is mountable. Structures of the bearing sleeve 27 and the wearing sleeve 30 may be uniform without the split configuration.
The drawings and the related description are only intended to illustrate the idea of the invention. In its details, the invention may vary within the scope of the claims.

Claims

A shank sleeve assembly (26) mountable around a shank adapter (8) in a rock drilling machine (6),
wherein
the sleeve assembly (26) comprises a shank bushing (27) with an inner surface facing towards the shank adapter (8) and being provided with an inwardly protruding shoulder (28), and comprising an outer surface;

the shank bushing (27) has two-piece configuration comprising a first bushing component (27a) and a second bushing component (27b) both provided with coupling surfaces (29) connectable in radial direction against each other; and

the shank sleeve assembly (26) further comprises a bearing bushing (30) arrangeable to surround the two-piece shank bushing (27);

characterized in that

the bearing bushing (30) comprises an inwardly facing shoulder (36) at a first end part of the bearing bushing (30); and

the shank bushing (27) comprises a first end facing towards drilling direction;

whereby a face surface at the first end of the shank bushing (27) is mountable against the shoulder (36) of the bearing bushing (30).
The assembly as claimed in claim 1, characterized in that
the two-piece shank bushing (27) is mounted rotatably in relation to the bearing bushing (30).
The assembly as claimed in claim 1, characterized in that
between the two-piece shank bushing (27) and the bearing bushing (30) only limited axial movement is allowed.
The assembly as claimed in claim 1, characterized in that
components of the two-piece shank bushing (27) are both mounted immovably to the bearing bushing (30).
The assembly as claimed in any one of the preceding claims 1 - 4, characterized in that
the bearing bushing (30) comprises rotation surfaces (31) on its outer circumference and is allowed to be rotatably mounted.
The assembly as claimed in any one of the preceding claims 1 - 5, characterized in the
the shank sleeve assembly (26) further comprises a wearing bushing (32) arrangeable to surround the bearing bushing (30).
The assembly as claimed in claim 6, characterized in that
one end of the wearing bushing (32) comprises a flange (33) protruding inwardly and providing a supporting axial surface for the bearing bushing (30).
The assembly as claimed in any one of the preceding claims 1 - 7, characterized in that
the first bushing component (27a) and the second bushing component (27b) are fastenable to each other removably to form together one uniform piece.
A rock drilling machine (6), comprising:
a frame (12, 16);

an impact device (9) for generating impact pulses;

a shank adapter (8) for receiving the impact pulses and transmitting them as stress waves to a drilling tool (7) connectable to the shank adapter (8);

a rotation device (10) for turning the shank adapter (8) around its longitudinal axis; and

a shank sleeve assembly (26) comprising a shank bushing (27) with split configuration surrounding the shank adapter (8) and configured to transmit axial forces between the frame (16) and the shank adapter (8);

characterized in that

the shank sleeve assembly (26) is in accordance with any one of the previous claims 1 - 8.
A method of providing a rock drilling machine (6) with a rotating shank bushing (27);
wherein the method comprises:
providing the shank bushing (27) with two-piece configuration comprising a first bushing component (27a) and a second bushing component (27b);

and arranging the bushing components (27a, 27b) to surround a shank adapter (8) of the rock drilling machine (6); and

surrounding the shank bushing (27) by means of a separate bearing bushing (30);

characterized by

providing the bearing bushing (30) with an inwardly facing shoulder (36) at a first end part of the bearing bushing (30);

providing the shank bushing (27) with a first end facing towards drilling direction; and

mounting a face surface at the first end of the shank bushing (27) against the shoulder (36) of the bearing bushing (30).
The method as claimed in claim 10, characterized by
allowing the two-piece shank bushing (27) to rotate around its longitudinal axis in relation to the bearing bushing (30).
The method as claimed in claim 10, characterized by
preventing rotation movement between the two-piece shank bushing (27) and the bearing bushing (30); and

allowing limited axial relative movement between the two-piece shank bushing (27) and the bearing bushing (30).
The method as claimed in claim 10, characterized by
mounting components of the two-piece shank bushing (27) immovably to the bearing bushing (30).
The method as claimed in any one of the preceding claims 11 - 13, characterized by
supporting the bearing bushing (30) rotationally in relation to a frame (16) of the rock drilling machine.
The method as claimed in claim 14, characterized by
supporting the bearing bushing (30) to the frame (16) by means of a separate wearing bushing (32) surrounding the bearing bushing (30).