Link device for work machine

Abstract

To provide a link device for a work machine allowing to be connected to a work tool.SOLUTION: A link device (10) of the present invention is provided with a single boom lifting arm (30) extending along a central longitudinal axis (L) and configured to lift a work tool; and a tilting device (40) having two hydraulic drive arms (42, 52) parallelly arranged and configured to tilt the working tool with respect to the single boom lifting arm. Each of two hydraulic drive arms is driven with each of hydraulic tilt cylinders (62, 64).SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a link device for a working implement of a working machine. The present invention further relates to a working machine including the link device, typically a wheel loader.

Background Art

[0002] Construction machines, i.e., working machines, are configured to perform work with working implements. For example, a working machine can be configured to lift, move, and discharge loads. Examples of such working machines include wheel loaders such as articulated wheel loaders.

[0003] A wheel loader typically includes a working implement such as a bucket configured to handle loads. To move the working implement with respect to the frame of the working machine, the working machine includes a link device. The link device includes a load support structure such as a lift arm configured to raise and lower the working implement. Further, the working machine may include certain connector means, i.e., a coupler, configured to connect the working machine to various types of working implements.

[0004] Since the link device has a large housing disposed in front of the operator's cab and at the center of the working machine, the operator's line of sight will be blocked when trying to operate the working implement. Also, the working implement itself can contribute to obstructing the line of sight. Further, additional arms and actuators may be required for appropriate torque distribution and suitable adjustment of the working implement, for example, tilting the working implement, which further contributes to blocking the field of view.

[0005] Thus, good visibility for the driver and sufficient functionality of the working implement are in a trade-off relationship. Therefore, an improved link device is needed in the art.

Summary of the Invention

Problems to be Solved by the Invention

[0006] The objective of the present invention is to overcome, at least to some extent, the aforementioned drawbacks related to link devices. [Means for solving the problem]

[0007] According to at least a first aspect of the present invention, a link device for a work machine that can be connected to a work tool is provided. The link device comprises a single boom lifting arm extending along a longitudinal central axis and configured to raise and lower a work tool, and a tilting device having two hydraulic drive arms arranged parallel to each other and configured to tilt the work tool with respect to the single boom lifting arm, each of the two hydraulic drive arms being hydraulically driven by a separate hydraulic tilting cylinder.

[0008] This provides a linkage device that is improved in relation to torque distribution to the work implement and operator visibility. Furthermore, the linkage device advantageously combines parallel arrangement and low weight. In other words, the configuration of this linkage device results in a specific arrangement between the linkage device and the work implement that has the advantages of using a single boom lifting arm (e.g., good visibility at all positions and low weight) and the advantages of having two parallel-arranged hydraulic drive arms that are hydraulically driven separately by separate hydraulic cylinders for the tilting device (e.g., torque distribution and parallel arrangement). The linkage device may also be called a boom loader mechanism. The work implement is typically a tool or attachment configured to perform work, and may also be called an attachment or accessory.

[0009] Since each of the two hydraulically driven arms is hydraulically driven by its own hydraulic tilting cylinder, it can be said that the tilting device is also configured to be hydraulically driven by separate hydraulic cylinders.

[0010] According to at least one exemplary embodiment, the linkage device is connectable to a workpiece by a coupler. The linkage device may include a coupler, or the workpiece may include a coupler. The coupler typically includes a first mounting means for a single boom lifting arm and a second mounting means for each of two hydraulically driven arms. According to at least one exemplary embodiment, the coupler is configured to connect the workpiece to various types of workpieces.

[0011] According to at least one exemplary embodiment, the two hydraulically driven arms are positioned at least partially outside the single boom lifting arm in a direction transverse to the longitudinal central axis.

[0012] This further enhances the torque distribution and parallel arrangement advantages of a configuration of two parallel-arranged hydraulic drive arms, each hydraulically driven separately by separate hydraulic cylinders. According to at least one exemplary embodiment, the two hydraulic drive arms are positioned outside, for example, entirely outside, the single boom lifting arm in a direction transverse to the longitudinal central axis. According to at least one exemplary embodiment, each of the two hydraulic drive arms extends along its respective longitudinal arm axis, and the two longitudinal arm axes are positioned in a vertical plane parallel to, or at least parallel to, the longitudinal central axis of the single boom lifting arm. Typically, the longitudinal central axis of the single boom lifting arm is positioned between the two longitudinal arm axes.

[0013] According to at least one exemplary embodiment, a single boom lifting arm is at least partially defined by two lateral sides extending in the same direction as the longitudinal central axis on either side of the longitudinal central axis, and two hydraulic drive arms are positioned outside, or at least partially outside, the lateral sides on either side of the longitudinal central axis.

[0014] According to at least one exemplary embodiment, the hydraulic tilting cylinder is positioned at least partially outside the single boom lifting arm in a direction transverse to the longitudinal central axis.

[0015] This further enhances the torque distribution and parallel arrangement advantages of a configuration of two parallel-arranged hydraulic drive arms, each hydraulically driven separately by separate hydraulic cylinders. According to at least one exemplary embodiment, the two hydraulic tilt cylinders are positioned outside, for example, entirely outside, the single boom lifting arm in a direction transverse to the longitudinal central axis. According to at least one exemplary embodiment, each of the two hydraulic tilt cylinders extends into the same vertical plane as the corresponding longitudinal arm axis. Thus, it can be said that the two hydraulic tilt cylinders are positioned in a vertical plane parallel to, or at least parallel to, the longitudinal central axis of the single boom lifting arm. Typically, the longitudinal central axis of the single boom lifting arm is positioned between the hydraulic tilt cylinders.

[0016] According to at least one exemplary embodiment, two hydraulic tilting cylinders are positioned on the outer or at least partially outer sides of the lateral surface of the single boom lifting arm, and on either side of the longitudinal central axis.

[0017] According to at least one exemplary embodiment, the hydraulic tilting cylinder is positioned vertically below the longitudinal central axis of the single boom lifting arm.

[0018] This arrangement of the hydraulic tilting cylinder improves the torque distribution and parallel alignment of the tilting mechanism. Furthermore, the positioning of the hydraulic tilting cylinder vertically below the longitudinal central axis of the single boom lifting arm improves operator visibility.

[0019] According to at least one exemplary embodiment, each of the two hydraulic drive arms has a first end connectable to a workpiece and a second end connected to a corresponding hydraulic tilting cylinder.

[0020] The first end of each hydraulic drive arm is positioned along its respective longitudinal arm axis, opposite to the corresponding second end. A hydraulic tilting cylinder is configured to transmit its induced motion to the second end of each hydraulic drive arm, which is further transmitted to the first end via two hydraulic drive arms to tilt the workpiece. In other words, a first hydraulic tilting cylinder is positioned adjacent to the first lateral side of the single boom lifting arm and is configured to transmit its induced motion to the second end of the first hydraulic drive arm, which is then configured to transmit the induced motion to its first end. A second hydraulic tilting cylinder is positioned adjacent to the second lateral side of the single boom lifting arm, which is positioned laterally opposite to the first lateral side, and is configured to transmit its induced motion to the second end of the second hydraulic drive arm, which is then configured to transmit the induced motion to its first end.

[0021] According to at least one exemplary embodiment, each of the two hydraulically driven arms includes an intermediate section positioned between its first and second ends, each intermediate section being rotatably coupled to a single boom lifting arm.

[0022] As a result, each of the two hydraulically driven arms is supported and rotatably positioned relative to the single boom lifting arm. This improves the torque distribution and parallel arrangement of the tilting mechanism.

[0023] According to at least one exemplary embodiment, the intermediate section is a first intermediate section, and each of the two hydraulically driven arms has a second intermediate section positioned between its respective first end and the first intermediate section, the second intermediate section being rotatably coupled to a single boom lifting arm.

[0024] As a result, each of the two hydraulic drive arms is further carried and additionally rotatably arranged with respect to the single boom lifting arm. Therefore, the torque distribution and parallel arrangement of the tilting device are improved. For example, each of the second intermediate parts is rotatably coupled to the single boom lifting arm via respective spacer arms. Such spacer arms further improve the possibility of transmitting motion from the tilting device to the working implement independently of the single boom lifting arm.

[0025] According to at least one exemplary embodiment, the single boom lifting arm is hydraulically driven by a hydraulic lifting cylinder.

[0026] Therefore, the single boom lifting arm is hydraulically driven by a hydraulic cylinder separate from the hydraulic drive arms of the tilting device. Therefore, the possibility of independent movement of the single boom lifting arm and the tilting device with respect to the working implement is improved.

[0027] According to at least one exemplary embodiment, the hydraulic lifting cylinder is at least partially arranged in the same horizontal plane as the hydraulic tilting cylinder.

[0028] This provides a concise or compact arrangement of the hydraulic cylinders (i.e., the two hydraulic tilting cylinders and the hydraulic lifting cylinder). According to at least one exemplary embodiment, the hydraulic lifting cylinder is arranged between the two hydraulic tilting cylinders when viewed in a direction transverse to the longitudinal central axis.

[0029] According to at least one exemplary embodiment, each of the hydraulic drive arms is a link-type arm having at least three linear sub-parts pivotally interconnected with each other.

[0030] This improves the configuration and torque distribution of the tilting mechanism. Thus, each hydraulic drive arm comprises at least three linear sub-sections, i.e., three arm portions, that are pivotably interconnected with one another. Typically, the at least three linear sub-sections are pivotably connected with one another at each end of the linear sub-section. For example, each hydraulic drive arm comprises a first linear sub-section, the first linear sub-section having a first end connected to a corresponding hydraulic tilting cylinder and a second end located along the first linear sub-section on the opposite side of the first end. The second end is pivotably connected to the first end of each of the second linear sub-sections. Furthermore, each of the second linear sub-sections has a second end located along the second linear sub-section on the opposite side of the first end, etc. Therefore, the second end of each hydraulic drive arm typically includes the first end of the first linear sub-section, and the first end of each hydraulic drive arm typically includes the second end of the tail linear sub-section (e.g., the third linear sub-section). According to at least one exemplary embodiment, each first intermediate section is located in the first linear sub-section of the hydraulic drive arm. Furthermore, or alternatively, each second intermediate section is located in the third linear sub-section of the hydraulic drive arm. The hydraulic drive arm may be referred to as a hydraulic drive arm device or a hydraulic drive link arm.

[0031] According to at least a second aspect of the present invention, a work machine equipped with a linkage device according to a first aspect of the present invention is provided.

[0032] The effects and features of the second aspect of the present invention are substantially the same as those described above in relation to the first aspect of the present invention. Embodiments described in relation to the first aspect of the present invention are substantially interchangeable with those of the second aspect of the present invention, some of which are illustrated below.

[0033] According to at least one exemplary embodiment, the work machine comprises a frame having a first mounting portion for pivotally connecting a single boom lifting arm, and a hydraulic tilting cylinder is mounted to the frame vertically below the first mounting portion. The frame may be called a work machine frame.

[0034] According to at least one exemplary embodiment, the working machine comprises a working tool. Therefore, the linkage device is connected to the working tool.

[0035] According to at least one exemplary embodiment, the working machine is a wheel loader. According to at least one exemplary embodiment, the working tool is a bucket.

[0036] Further advantages and features of this disclosure are disclosed and described in the following description and accompanying drawings.

[0037] The embodiments of the present invention, as given in the attached drawings, will be described in more detail below with reference to the attached drawings. [Brief explanation of the drawing]

[0038] [Figure 1] This is a schematic side view of a work machine equipped with a link device for work tools according to an exemplary embodiment of the present invention. [Figure 2] This is a schematic side view of a link device and work tool according to an exemplary embodiment of the present invention. [Figure 3] This is a schematic top view showing the linkage device of Figure 2 without any working tools, according to an exemplary embodiment of the present invention. [Modes for carrying out the invention]

[0039] Referring to Figure 1, a working machine 1 is disclosed, embodied here as a wheel loader 1, in which the type of linkage device 10 disclosed in the present invention is advantageous. However, the linkage device 10 can also be implemented in other types of working machines, such as excavators. The working machine 1 may be an all-electric working machine or an all-electric working machine such as a hybrid, comprising at least one electric machine. Such an electric machine may be powered by a rechargeable energy storage system RESS, such as a battery system or a fuel cell system.

[0040] As shown in Figure 1, the linkage device 10 is connected to the work tool 20, which is a bucket 20. The linkage device 10 includes a single boom lifting arm 30 configured to raise and lower the work tool 20, and a tilting device 40 configured to tilt the work tool 20 relative to the single boom lifting arm 30. Next, the linkage device 10 will be described in more detail with reference to Figures 2 and 3.

[0041] Figure 2 is a schematic side view of the link device 10 connected to the work implement 20 in Figure 1, and Figure 3 is a schematic top view of the link device 10 without the work implement 20. Thus, the embodiments shown in Figures 2 and 3 can be implemented in the work machine 1 of Figure 1. As shown in Figure 1, the link device 10 comprises a single boom lifting arm 30 and a tilting device 40. The single boom lifting arm 30 extends along its longitudinal central axis L. The single boom lifting arm 30 is not uniformly straight, but is slightly curved or formed by a combination of a finite number of straight segments. Therefore, the longitudinal central axis L of the single boom lifting arm is not a straight axis, but an axis formed by a combination of a finite number of corresponding line segments angled relative to each other. In Figure 2, the single boom lifting arm 30 is connected to or attached to the work equipment 20 and configured to raise and lower the work equipment 20, while the tilting device 40 is connected to or attached to the work equipment 20 and configured to tilt the work equipment 20. The tilting device 40 is typically connected to or attached to the work equipment 20 vertically above the position where the single boom lifting arm 30 is connected to or attached to the work equipment 20.

[0042] The tilting device 40 shown in Figures 2-3 comprises two hydraulic drive arms 42, 52, which are referred to herein as a first hydraulic drive arm 42 and a second hydraulic drive arm 52. As seen at least in Figure 3, the first and second hydraulic drive arms 42, 52 are arranged parallel to each other on different sides of the single boom lifting arm 30. Furthermore, the tilting device 40 comprises two hydraulic tilting cylinders 62, 64, which are referred herein as a first hydraulic tilting cylinder 62 and a second hydraulic tilting cylinder 64. The first hydraulic tilting cylinder 62 is configured to operate the first hydraulic drive arm 42 and the second hydraulic tilting cylinder 64 is configured to operate the second hydraulic drive arm 52 so that the work implement 20 tilts relative to the single boom lifting arm 30. Thus, each of the two hydraulic drive arms 42, 52 is hydraulically driven by a separate hydraulic tilting cylinder 62, 64.

[0043] As best seen in Figure 3, the first and second hydraulic drive arms 42, 52 are positioned at least partially outside the single boom lifting arm 30 in a direction T that crosses the longitudinal central axis L. The single boom lifting arm 30 includes a first coupling portion 32 for connecting to or attaching to the work machine 1 or the frame 3 of the work machine 1 (as shown in Figure 1), and a second coupling portion 34 positioned on the opposite side of the first coupling portion 32 along the longitudinal central axis L and configured to connect to or attach to the work implement 20. The single boom lifting arm 30 further includes a central portion 36 that occupies most of the total length of the single boom lifting arm 30 along the longitudinal central axis L. The central portion 36 is positioned between the first coupling portion 32 and the second coupling portion 34 and may extend, for example, from the first coupling portion 32 to the second coupling portion 34. As shown in Figure 3, the first and second hydraulic drive arms 42, 52 are positioned outside the single boom lifting arm 30, at least the central portion 36, in a direction T that crosses the longitudinal central axis L. In other words, and according to at least one exemplary embodiment, the first and second hydraulic drive arms 42, 52 are positioned outside the single boom lifting arm 30, along at least the majority of the length of the single boom lifting arm 30 (the length is defined along the longitudinal central axis L), in a direction T that crosses the longitudinal central axis L.

[0044] Similarly, and according to at least one exemplary embodiment, the first and second hydraulic tilting cylinders 62, 64 are positioned at least partially outside the single boom lifting arm 30 in a direction T across the longitudinal central axis L. As seen in Figure 3, the first and second hydraulic tilting cylinders 62, 64 are positioned outside at least the central portion 36 of the single boom lifting arm 30 in a direction T across the longitudinal central axis L. In other words, and according to at least one exemplary embodiment, the first and second hydraulic tilting cylinders 62, 64 are positioned outside the single boom lifting arm 30 for at least a large portion of its length in a direction T across the longitudinal central axis L.

[0045] As shown in Figure 2, the first and second hydraulic tilting cylinders 62 and 64 are positioned vertically below the longitudinal central axis L of the single boom lifting arm 30. In other words, at least in the horizontal position of the linkage device 10 (i.e., in the position where the single boom lifting arm 30 is positioned to extend horizontally from the frame 3 of the work machine 1), the first and second hydraulic tilting cylinders 62 and 64 are positioned vertically below the longitudinal central axis L of the single boom lifting arm 30.

[0046] The single boom lifting arm 30 can be described as being at least partially defined by two lateral sides 31A, 31B extending in the same direction as the longitudinal central axis L on either side of the longitudinal central axis L. Thus, the first and second hydraulic drive arms 42, 52 are positioned outside the lateral sides 31A, 31B on either side of the longitudinal central axis L. Similarly, the hydraulic tilting cylinders 62, 64 are positioned at least partially outside the lateral sides 31A, 31B on either side of the longitudinal central axis L.

[0047] The positional relationship between the single boom lifting arm 30 and its longitudinal central axis L, the first and second hydraulic drive arms 42, 52, and the first and second hydraulic tilting cylinders 62, 64, provides an improved linkage device 10 in terms of torque distribution to the work tool 20 and operator visibility.

[0048] As seen in both Figures 2 and 3, each of the first and second hydraulic drive arms 42, 52 has a first end 43, 53 connectable to the workpiece 20 and a second end 44, 54 connected to the corresponding hydraulic tilting cylinders 62, 64. That is, the first hydraulic drive arm 42 has a first end 43 connectable to the workpiece 20 and a second end 44 connected to the first hydraulic tilting cylinder 62. Similarly, the second hydraulic drive arm 52 has a first end 53 connectable to the workpiece 20 and a second end 54 connected to the second hydraulic tilting cylinder 64. Furthermore, in the embodiments of Figures 2 and 3, each of the first and second hydraulic drive arms 42, 52 has a first intermediate section 45, 55 positioned between its respective first end 43, 53 and second end 44, 54. The first intermediate sections 45, 55 are each rotatably coupled to the single boom lifting arm 30. For the first hydraulic drive arm 42, this is shown as a rotary coupling 45A in Figure 2. For the second hydraulic drive arm 52, a similar rotary coupling is located on the other side surface 31B of the single boom lifting arm 30. Furthermore, each of the first and second hydraulic drive arms 42, 52 includes second intermediate sections 46, 56 located between their respective first ends 43, 53 and first intermediate sections 45, 55. Each of the second intermediate sections 46, 56 is rotatably coupled to the single boom lifting arm. For the first hydraulic drive arm 42, this is shown as a rotary coupling 46A in Figure 2. For the second hydraulic drive arm 52, a similar rotary coupling is located on the other side surface 31B of the single boom lifting arm 30. As seen in Figure 2, the first hydraulic drive arm 42 is rotatably coupled to the single boom lifting arm by a spacer arm 47. A similar spacer arm for a second hydraulic drive arm 52 is positioned on the other lateral side 31B of the single boom lifting arm 30.

[0049] The single boom lifting arm 30 is hydraulically driven by a hydraulic lifting cylinder 32. The hydraulic lifting cylinder 32 is positioned along the longitudinal central axis L and is typically positioned parallel to the vertical direction of the single boom lifting arm 30. Furthermore, as seen in Figure 2, the hydraulic lifting cylinder 32 is positioned in the same horizontal plane as the first and second hydraulic tilting cylinders 62, 64, at least partially. Thus, the hydraulic lifting cylinder 32 is positioned between the first and second hydraulic tilting cylinders 62, 64 when viewed across the longitudinal central axis L, thereby providing a concise or compact arrangement of the hydraulic cylinders 32, 62, 64.

[0050] As is most clearly shown in Figure 2, the first and second hydraulic drive arms 42 and 52 are link-type arms 42 and 52, respectively. In the following description of the configuration of such link-type arms 42 and 52, only the first hydraulic drive arm 42 will be used as a reference, but a similar configuration is assumed for the second hydraulic drive arm 52. The first hydraulic drive arm 42 comprises at least three linear sub-sections 42A, 42B, and 42C, which are pivotally connected to each other and referred to here as the first linear sub-section 42A, the second linear sub-section 42B, and the third linear sub-section 43B. These linear sub-sections 42A, 42B, and 42C can also be referred to as arm sections 42A, 42B, and 42C. The first, second, and third linear sub-sections 42A, 42B, and 42C are pivotally connected to each other at their respective ends. For example, the first linear sub-part 42A has a first end connected to the first hydraulic tilting cylinder 62 and a second end located along the first linear sub-part 42A on the opposite side of the first end, the second end being pivotably connected to the corresponding first end of the second linear sub-part 42B. Furthermore, the second linear sub-part 42B has a second end located along the second linear sub-part 42B on the opposite side of the first end, the second end being pivotably connected to the first end of the third linear sub-part 42C. Thus, typically, the second end 44 of the first hydraulic drive arm 42 is included in the first linear sub-part 42A and its first end, and the first end 43 of the first hydraulic drive arm 42 is included in the third linear sub-part 42C and its second end. If the first hydraulic drive arm 42 has a fourth linear sub-section positioned following a third linear sub-section 42C, the first end 43 of the first hydraulic drive arm 42 is typically included in the fourth linear sub-section and its second end. Typically, the linear sub-section of the first hydraulic drive arm 42 that is positioned closest to or connected to the workpiece 20 is called the tail linear sub-section. As seen in Figure 2, the first intermediate section 45 of the first hydraulic drive arm 42 is positioned in the first linear sub-section 42A, and the second intermediate section 46 of the first hydraulic drive arm 42 is positioned in the third linear sub-section 42C.The first and second hydraulic drive arms 42 and 52 can be referred to as the first and second hydraulic drive arm devices or the first and second hydraulic drive link arms, respectively.

[0051] Returning briefly to Figure 1, Figure 1 shows a work machine 1 comprising the linkage device 10 of Figures 2-3 and a work tool 20 in the form of a bucket 20. The work machine 1 comprises a frame 3, the frame 3 having a first mounting portion 5 to pivotally connect a single boom lifting arm 30 to the frame 3. Furthermore, the frame 3 comprises a second mounting portion 7 to connect first and second hydraulic tilting cylinders 62, 64, respectively, to the frame 3. The second mounting portion 7 is positioned vertically below the first mounting portion 5.

[0052] The present invention is not limited to the embodiments described above and shown in the drawings; rather, those skilled in the art will recognize that many changes and modifications can be made within the scope of the appended claims.

[0053] Furthermore, modifications to the disclosed embodiments can be understood and achieved by those skilled in the art practicing the claimed inventive concept by examining the drawings, this disclosure, and the appended claims. In the claims, the word “comprising” does not preclude other elements or steps, and the indefinite article “a” or “an” does not preclude plural. The mere fact that certain means are described in different dependent claims does not imply that combinations of these means cannot be used advantageously.

Claims

1. A link device (10) for a working machine that can be connected to a working implement (20), comprising a single boom lifting arm (30) that extends along a longitudinal central axis (L) and is configured to raise and lower the working implement, and a tilting device (40) having two hydraulically driven arms (42, 52) arranged in parallel and configured to tilt the working implement with respect to the single boom lifting arm, wherein each of the two hydraulically driven arms is hydraulically driven by a separate hydraulic tilting cylinder (62, 64).

2. The link device according to claim 1, wherein the two hydraulically driven arms are arranged at least partially outside the single boom lifting arm in a direction (T) crossing the longitudinal central axis.

3. The link device according to claim 1 or 2, wherein the hydraulic tilting cylinder is arranged at least partially outside the single boom lifting arm in a direction crossing the longitudinal central axis.

4. The link device according to claim 1 or 2, wherein the hydraulic tilting cylinder is arranged vertically below the longitudinal central axis of the single boom lifting arm.

5. The link device according to claim 1 or 2, wherein each of the two hydraulically driven arms has a first end (43, 53) connectable to the working implement and a second end (44, 54) connected to the corresponding hydraulic tilting cylinder.

6. The link device according to claim 5, wherein each of the two hydraulically driven arms comprises an intermediate portion (45, 55) arranged between the respective first end and second end, and each intermediate portion is rotatably coupled to the single boom lifting arm.

7. The intermediate portion is a first intermediate portion, and each of the two hydraulically driven arms comprises a second intermediate portion (46, 56) arranged between the respective first end and the first intermediate portion, The link device according to claim 6, wherein the second intermediate portion is rotatably coupled to the single boom lifting arm.

8. The link device according to claim 1 or 2, wherein the single boom lifting arm is hydraulically driven by a hydraulic lifting cylinder.

9. The link device according to claim 8, wherein the hydraulic lifting cylinder is arranged at least partially in the same horizontal plane as the hydraulic tilting cylinder.

10. The link device according to claim 1 or 2, wherein each of the hydraulic drive arms is a link-type arm having at least three linear sub-parts pivotally interconnected with each other.

11. A working machine (1) comprising the link device according to claim 1 or 2.

12. Comprising a frame (3) having a first mounting portion (5) for pivotally connecting the single boom lifting arm. The working machine according to claim 11, wherein the hydraulic tilting cylinder is mounted to the frame below the first mounting portion in the vertical direction.

13. The working machine according to claim 11, further comprising the working implement.

14. The working machine according to claim 11, wherein the working machine is a wheel loader.

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