crane

Abstract

The present invention discloses a crane, comprising: a chassis; a lifting arm; a superlift mast group, comprising a first superlift mast and a second superlift mast arranged in a V shape; a first adjusting device for rotating the first superlift mast and the second superlift mast relative to the chassis, so as to adjust the distance between the second end of the first superlift mast and the second end of the second superlift mast in a direction perpendicular to a variable-length plane; a counterweight group, comprising a first counterweight and a second counterweight respectively suspended on the second end of the first superlift mast and the second end of the second superlift mast through a first suspension line and a second suspension line; a second adjusting device, comprising a first telescopic device, which, in a following state, telescopes and expands and contracts as the distance between the first suspension line and the second suspension line changes, and in a non-following state, the first telescopic device is used to actively telescope and expand to adjust the distance between the first counterweight below the first suspension line and the second counterweight below the second suspension line in a direction perpendicular to the variable-length plane.

Description

Technical Field

[0001] The present invention relates to the field of lifting machinery, in particular to a crane. Background Art

[0002] The existing superlift mast and the boom are in the same plane, that is, in the boom's luffing plane. The superlift mast can play a great role in various working conditions of the boom in the luffing plane, but has little effect on resisting the lateral deformation of the boom (lateral refers to the direction perpendicular to the luffing plane). When the boom exceeds a certain length, the performance of the entire machine is limited by the size of the lateral deformation of the boom, and the performance of the entire machine and the boom cannot be fully utilized. Summary of the Invention

[0003] An object of the present invention is to provide a crane capable of improving the lateral force state of the crane boom.

[0004] The present invention discloses a crane, comprising:

[0005] chassis;

[0006] A lifting arm including a first end connected to the chassis and a second end for lifting a load;

[0007] a superlift mast assembly, comprising a first superlift mast and a second superlift mast arranged in a V-shape, wherein the first ends of the first superlift mast and the second superlift mast are both rotatably connected to the chassis, and the second ends of the first superlift mast and the second superlift mast are located on both sides of the luffing plane of the boom and are both connected to the second end of the boom via luffing ropes;

[0008] a first adjusting device connected between the first superlift mast and the second superlift mast, for rotating the first superlift mast and the second superlift mast relative to the chassis to adjust the distance between the second end of the first superlift mast and the second end of the second superlift mast in a direction perpendicular to the luffing plane;

[0009] a counterweight group, comprising a first counterweight and a second counterweight suspended on the second end of the first superlift mast and the second end of the second superlift mast respectively via a first suspension line and a second suspension line;

[0010] The second adjusting device is connected between the first suspension line and the second suspension line, and includes a first telescopic device. The first telescopic device has a switchable following state and a non-following state. In the following state, the first telescopic device is telescopic and follows the change of the distance between the first suspension line and the second suspension line. In the non-following state, the first telescopic device is used to actively telescope and adjust the distance between the first counterweight below the first suspension line and the second counterweight below the second suspension line in a direction perpendicular to the amplitude variation plane.

[0011] In some embodiments, the second adjusting device further comprises a second telescopic device, and the second telescopic device is used to telescope to adjust the distance between the first counterweight and the second counterweight and the second end of the boom along a horizontal direction parallel to the luffing plane.

[0012] In some embodiments, the second adjustment device includes a first rod, a second rod, a third rod and a fourth rod, the first ends of the first rod and the second rod are hinged to the chassis, the second end of the first rod and the first end of the third rod are hinged, the second end of the third rod is connected to the first suspension line, the second end of the second rod and the first end of the fourth rod are hinged, the second end of the fourth rod is connected to the second suspension line, the first rod and the second rod are arranged in a V shape, the second end of the first rod and the second end of the second rod are located on both sides of the amplitude variation plane, any three of the first rod, the second rod, the third rod and the fourth rod are not coplanar, the first telescopic device is connected between the first rod and the second rod, and the second telescopic device includes a first telescopic member connected between the first rod and the third rod and a second telescopic member connected between the second rod and the fourth rod.

[0013] In some embodiments, the first adjustment device comprises a length-adjustable rope connected between the first superlift mast and the second superlift mast.

[0014] In some embodiments, a third telescopic device is further included, which includes a third telescopic member arranged between the first counterweight and the first suspension line and a fourth telescopic member arranged between the second counterweight and the second suspension line. The third telescopic device is configured to: separate the first counterweight and the second counterweight from the ground so that the counterweight group has a fully counterweighted state or partially support the weight of the first counterweight and the weight of the second counterweight on the ground so that the counterweight group has a partially counterweighted state.

[0015] In some embodiments, the first telescopic device includes a telescopic cylinder, which includes a piston rod and a cylinder barrel. The crane also includes a hydraulic system for controlling the telescopic cylinder. The hydraulic system is configured to enable the telescopic cylinder to have a floating state in which the piston rod can slide freely relative to the cylinder barrel and a controlled state in which the position of the piston rod relative to the cylinder barrel is controlled by pressurized oil.

[0016] In some embodiments, it also includes a main variable-length mast whose first end is connected to the chassis, and the second end of the main variable-length mast is simultaneously connected to the second end of the first super-lift mast and the second end of the second super-lift mast through a pull plate, and the second end of the main variable-length mast is connected by a rope with adjustable length.

[0017] Based on the crane provided by the present invention, by arranging the first and second superlift masts and the first and second counterweights in a V-shape, the lateral stress state of the boom can be improved. Simultaneously, by providing a first adjustment device and a second adjustment device including a first telescopic device having a mixed follower state and a non-follower state, when the first adjustment device adjusts the distance between the second ends of the first and second superlift masts, the first telescopic device can switch to a follower state, so that the first and second counterweights can move in accordance with the movement of the second ends of the first and second superlift masts, allowing the first and second counterweights to move in a coordinated manner, thereby achieving more coordinated adjustment of the lateral stress state of the boom. When the first telescopic device is in the non-follower state, the distance between the first and second counterweights can be adjusted independently by the first telescopic device to adjust the lateral stress state of the boom.

[0018] Further features and advantages of the present invention will become apparent from the following detailed description of exemplary embodiments of the present invention with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of this application. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0020] Figure 1 A schematic structural diagram of a crane according to some embodiments of the present invention;

[0021] Figure 2 Schematic diagrams of the structures of cranes according to other embodiments of the present invention;

[0022] Figure 3 Schematic diagrams of the structures of cranes according to some other embodiments of the present invention;

[0023] Figure 4 for Figure 1 A schematic structural diagram of a portion of the crane shown;

[0024] Figure 5 for Figure 4 A schematic diagram of a top view of the structure shown;

[0025] Figure 6 Schematic diagrams of partial structures of cranes according to some embodiments of the present invention;

[0026] Figure 7 Schematic diagram of the structure of part of the crane according to some embodiments of the present invention. DETAILED DESCRIPTION

[0027] The following will be combined with the accompanying drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, rather than all the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is in no way intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0028] Unless otherwise specifically stated, the relative arrangement of the parts and steps, the numerical expressions and the numerical values set forth in these embodiments do not limit the scope of the present invention. At the same time, it should be understood that, for ease of description, the sizes of the various parts shown in the drawings are not drawn according to the actual proportional relationship. The techniques, methods and equipment known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, the techniques, methods and equipment should be considered as part of the authorization specification. In all examples shown and discussed here, any specific values should be interpreted as being merely exemplary and not as limiting. Therefore, other examples of the exemplary embodiments may have different values. It should be noted that similar numbers and letters represent similar items in the following figures, and therefore, once an item is defined in one figure, it does not need to be further discussed in subsequent figures.

[0029] In the description of the present invention, it should be understood that the use of terms such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore cannot be understood as limiting the scope of protection of the present invention.

[0030] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used herein to describe the spatial positional relationship of a device or feature to other devices or features as shown in the figures. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figures. For example, if the device in the drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0031] like Figures 1 to 6 As shown, the crane of this embodiment includes a chassis 11, a lifting arm 12, a super-lift mast group 2, a first adjusting device 23, a counterweight group 3 and a second adjusting device 4.

[0032] In some embodiments, the chassis 11 is a tracked chassis 11 , and in other embodiments, the chassis 11 is a wheeled chassis.

[0033] The boom 12 includes a first end connected to the chassis 11 and a second end for lifting a load. The first end of the boom 12 is connected to the slewing support structure of the chassis 11, and the slewing support structure of the chassis 11 can slew the boom 12.

[0034] like Figure 1 and Figure 2As shown, the superlift mast assembly 2 includes a first superlift mast 21 and a second superlift mast 22 arranged in a V-shape. The V-shaped arrangement of the first superlift mast 21 and the second superlift mast 22 means that the shape of the first superlift mast 21 and the second superlift mast 22 after arrangement is similar to a V-shape. The first end of the first superlift mast 21 and the first end of the second superlift mast 22 are both rotatably connected to the chassis 11. In an embodiment not shown in the figure, the first end of the first superlift mast 21 and the first end of the second superlift mast 22 can be hinged to the chassis. In the embodiment shown in the figure, the first end of the first superlift mast 21 and the first end of the second superlift mast 22 can be connected to the chassis via a bottom connecting device 53. The first end of the first superlift mast 21 and the first end of the second superlift mast 22 are first hinged to the bottom connecting device 53, and then the bottom connecting device 53 is hinged to the chassis, so that the first superlift mast 21 and the second superlift mast 22 can rotate in two directions relative to the chassis. The first end of the first superlift mast 21 and the first end of the second superlift mast 22 can rotate relative to the chassis 11 to move the second ends of the first superlift mast 21 and the second superlift mast 22 closer together or further apart, thereby narrowing or widening the opening of the "V" formed by the first superlift mast 21 and the second superlift mast 22. The second ends of the first superlift mast 21 and the second superlift mast 22 are located on either side of the luffing plane of the boom 12 and are connected to the second end of the boom 12 via luffing ropes. The luffing ropes are conventional components of a crane's luffing operation and consist of pulleys and ropes located between them. The rope length is adjusted by moving the movable pulleys to adjust the luffing of the boom. In the embodiment shown in the figure, the superlift mast assembly 2 is connected to the second end of the boom 12 via a luffing rope assembly 5. Specifically, the first superlift mast 21 is connected to the second end of the boom via a first luffing rope 51, and the second superlift mast 22 is connected to the second end of the boom via a second luffing rope 52. When the lengths of the first luffing ropes 51 and the second luffing ropes 52 are changed simultaneously, the boom can achieve luffing within the luffing plane.

[0035] A first adjustment device 23 is connected between the first and second superlift masts 21, 22. The first adjustment device 23 is used to rotate the first and second superlift masts 21, 22 relative to the chassis 11 to adjust the distance between the second ends of the first and second superlift masts 21, 22 in a direction perpendicular to the luffing plane. This adjustment device, in turn, adjusts the size of the V-shaped opening formed by the first and second superlift masts 21, 22. In the embodiment shown, the first adjustment device 23 is a length-adjustable rope, similar in structure to the luffing rope structure.

[0036] like Figures 1 to 3As shown, the counterweight assembly 3 includes a first counterweight 31 and a second counterweight 32, which are suspended from the second end of the first superlift mast 21 and the second end of the second superlift mast 22 via a first suspension line 33 and a second suspension line 34, respectively. The first suspension line 33 and the second suspension line 34 may be structures such as pull plates, ropes, etc. The first counterweight 31 is suspended from the second end of the first superlift mast via the first suspension line 33, and the second counterweight 32 is suspended from the second end of the second superlift mast via the second suspension line 34.

[0037] The second adjusting device 4 is connected between the first suspension line 33 and the second suspension line 34, and includes a first telescopic device 45. The first telescopic device 45 has a switchable following state and a non-following state.

[0038] In the following state, the first telescopic device 45 is telescopically extended and retracted as the distance between the first suspension line 33 and the second suspension line 34 changes. That is, at this time, the first telescopic device 45 is freely extended and retracted, and the length of the telescopic device 45 is not locked. The position change of the first suspension line 33 and the second suspension line 34 will cause the length of the telescopic device 45 to change accordingly. In this state, when the first adjustment device 23 causes the first superlift mast 21 and the second superlift mast 22 to rotate relative to the chassis 11, that is, when the lateral force state of the boom is adjusted, the first superlift mast 21 and the second superlift mast 22 can drive the first suspension line 33 and the second suspension line 34 to move accordingly, so that the first counterweight 31 and the second counterweight 32 move accordingly to a matching position. For example, when the first superlift mast 21 and the second superlift mast 2 rotate away from each other to further increase the lateral force stability of the boom, that is, when the opening of the "V-shape" formed by the first superlift mast 21 and the second superlift mast 22 increases, the first counterweight 31 and the second counterweight 32 are respectively driven to move away from each other, and the first telescopic device 45 extends accordingly. The first counterweight 31 and the second counterweight 32 can further increase the lateral force stability of the boom, matching the position movement of the first superlift mast 21 and the second superlift mast 22.

[0039] In the non-following state, the first telescopic device 45 is used to actively extend and retract to adjust the distance between the first counterweight 31 below the first suspension line 33 and the second counterweight 32 below the second suspension line 34 in a direction perpendicular to the luffing plane. In the non-following state, the first telescopic device 45 does not follow the positional movement of the first suspension line 33 and the second suspension line 34. That is, the first telescopic device 45 requires the operator to actively control its telescopic state. The telescopic length of the first telescopic device 45 can be locked after control and adjustment. That is, in this state, the active extension and retraction of the first telescopic device 45 can be used to adjust the distance between the first counterweight 31 and the second counterweight 32. Therefore, while the positions of the first and second superlift masts 21 and 22 remain unchanged, the lateral force stability of the boom 12 can be adjusted only by adjusting the distance between the first and second counterweights 31 and 32.

[0040] The crane of this embodiment utilizes a V-shaped arrangement of the first and second superlift masts 21, 22, and the first and second counterweights 31, 32 to improve the lateral stress on the boom 12. Furthermore, by providing a first adjustment device 23 and a second adjustment device 4 comprising a first telescopic device 45 having both a follower state and a non-follower state, when the first adjustment device 23 adjusts the distance between the second ends of the first and second superlift masts 21, 22, the first telescopic device 45 can switch to a follower state, allowing the first and second counterweights 31, 32 to follow the movement of the second ends of the first and second superlift masts 21, 22. This allows for coordinated movement of the first and second counterweights 31, 32, resulting in more coordinated adjustment of the lateral stress on the boom 12. When the first telescopic device 45 is in the non-follower state, the distance between the first and second counterweights 31, 32 can be independently adjusted by the first telescopic device 45 to adjust the lateral stress on the boom 12.

[0041] In some embodiments, as Figures 1 to 6 As shown, the second adjustment device 4 also includes a second telescopic device, which is used to extend and retract to adjust the distance between the first counterweight 31 and the second counterweight 32 and the second end of the boom 12 in a horizontal direction parallel to the luffing plane. The second telescopic device can actively adjust the position of the first counterweight 31 and the second counterweight 32 in another direction, thereby adjusting the balance ability of the boom along the lifting direction when lifting a load.

[0042] In some embodiments, as Figure 1 、 Figure 2 、 Figure 4 、 Figure 5 and Figure 6As shown, the second adjusting device 4 includes a first rod 41, a second rod 42, a third rod 43 and a fourth rod 44, the first ends of the first rod 41 and the second rod 42 are hinged to the chassis 11, the second end of the first rod 41 and the first end of the third rod 43 are hinged, the second end of the third rod 43 is connected to the first suspension line 33, the second end of the second rod 42 and the first end of the fourth rod 44 are hinged, the second end of the fourth rod 44 is connected to the second suspension line 34, the first rod 41 and the second rod 42 are arranged in a V shape, the second end of the first rod 41 and the second end of the second rod 42 are located on both sides of the amplitude variation plane, any three of the first rod 41, the second rod 42, the third rod 43 and the fourth rod 44 are not coplanar, the first telescopic device 45 is connected between the first rod 41 and the second rod 42, the second telescopic device includes a first telescopic member 461 connected between the first rod 41 and the third rod 43 and a second telescopic member 462 connected between the second rod 42 and the fourth rod 44. The first rod 41, the second rod 42, the third rod 43 and the fourth rod 44 form a connecting rod structure of a spatial structure. Through this arrangement, the cooperation of the first telescopic device and the second telescopic device can realize the independent position change of the first counterweight 31 and the second counterweight 32 in the direction away from each other and in the horizontal direction parallel to the amplitude change plane, as well as the simultaneous position change in the direction away from each other and in the horizontal direction parallel to the amplitude change plane. The position adjustment of the first counterweight 31 and the second counterweight 32 in multiple directions can be realized through a simple spatial connecting rod structure, thereby conveniently adjusting the balancing ability of the crane in multiple directions.

[0043] In some embodiments, as Figure 2 As shown, the first adjustment device 23 includes a length-adjustable rope connected between the first superlift mast 21 and the second superlift mast 22. By varying the length of the rope and combining it with the weight of the first superlift mast 21 and the second superlift mast 22, the size of the "V-shaped" opening between the first superlift mast 21 and the second superlift mast 22 can be conveniently adjusted.

[0044] In some embodiments, as Figure 4As shown, the crane further includes a third telescopic device, comprising a third telescopic member 35 disposed between the first counterweight 31 and the first suspension line 33, and a fourth telescopic member 36 disposed between the second counterweight 32 and the second suspension line 34. The third telescopic device is configured to lift the first counterweight 31 and the second counterweight 32 off the ground to achieve a fully counterweighted state, or to partially support the weight of the first counterweight 31 and the second counterweight 32 on the ground to achieve a partially counterweighted state. In the fully counterweighted state, the third telescopic member 35 and the fourth telescopic member 36 are retracted, and the upper portions of the first counterweight 31 and the second counterweight 32 are suspended from the superlift mast assembly via the first suspension line 33 and the second suspension line 34, while the lower portions of the first counterweight 31 and the second counterweight 32 are suspended in the air. In other words, the weight of the first counterweight 31 and the second counterweight 32 is completely supported by the first suspension line and the second suspension line, and the entire weight of the first counterweight 31 and the second counterweight 32 is applied to the crane for counterweight balancing. In the partial counterweight state, the third telescopic member 35 and the fourth telescopic member 36 are extended to a certain length. At this length, the upper portions of the first counterweight 31 and the second counterweight 32 are suspended from the superlift mast assembly via the first suspension line 33 and the second suspension line 34, while the lower portions of the first counterweight 31 and the second counterweight 32 are partially in contact with the ground. This means that part of the weight of the first counterweight 31 and the second counterweight 32 is supported by the first suspension line and the second suspension line, while the remaining part is supported by the ground. Part of the weight of the first counterweight 31 and the second counterweight 32 is applied to the crane to balance the load. By providing the third telescopic device, this embodiment allows the counterweight assembly 3 to be switched to the full counterweight state when the crane is lifting heavy objects, maximizing the crane's lifting capacity. When the crane is lifting lighter objects, the counterweight assembly 3 can be switched to the partial counterweight state, reducing the pressure load on the crane from the counterweight assembly 3, improving the crane's load conditions, and extending the life of the crane's components and service life.

[0045] In some embodiments, the first telescopic device 45 comprises a telescopic cylinder comprising a piston rod and a cylinder barrel. The crane further comprises a hydraulic system for controlling the telescopic cylinder. The hydraulic system is configured to enable the telescopic cylinder to have two states: a floating state, in which the piston rod can slide freely relative to the cylinder barrel, and a controlled state, in which the position of the piston rod relative to the cylinder barrel is controlled by pressurized oil. In this embodiment, switching the telescopic cylinder between the floating state and the controlled state enables switching of the first telescopic device 45 between a follower state and a non-follower state.

[0046] In some embodiments, as Figure 1As shown, the crane also includes a main luffing mast 13, the first end of which is connected to the chassis. The second end of the main luffing mast 13 is connected to the second ends of the first and second superlifting masts 21 and 22 via a pull plate. The second ends of the main luffing mast 13 are connected by a length-adjustable rope. By adjusting the length of the rope, the first and second superlifting masts 21 and 22 can be rotated perpendicular to the luffing plane.

[0047] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to preferred embodiments, ordinary technicians in the field should understand that the specific implementation methods of the present invention can still be modified or some technical features can be replaced by equivalents without departing from the spirit of the technical solutions of the present invention. They should all be included in the scope of the technical solutions claimed for protection by the present invention.

Claims

1. A crane, characterized in that: include: chassis (11); A lifting arm (12) comprising a first end connected to the chassis (11) and a second end for lifting a load; A superlift mast group (2) comprises a first superlift mast (21) and a second superlift mast (22) arranged in a V-shape, wherein the first ends of the first superlift mast (21) and the second superlift mast (22) are both rotatably connected to the chassis (11), and the second ends of the first superlift mast (21) and the second ends of the second superlift mast (22) are located on both sides of the variable amplitude plane of the boom (12) and are both connected to the second end of the boom (12) via variable amplitude ropes; a first adjusting device (23) connected between the first superlift mast (21) and the second superlift mast (22), for rotating the first superlift mast (21) and the second superlift mast (22) relative to the chassis (11) to adjust the distance between the second end of the first superlift mast (21) and the second end of the second superlift mast (22) in a direction perpendicular to the amplitude change plane, the first adjusting device (23) comprising a length-adjustable rope connected between the first superlift mast (21) and the second superlift mast (22); A counterweight group (3) comprising a first counterweight (31) and a second counterweight (32) respectively suspended on the second end of the first superlift mast (21) and the second end of the second superlift mast (22) via a first suspension line (33) and a second suspension line (34); The second adjusting device (4) is connected between the first suspension line (33) and the second suspension line (34), and includes a first telescopic device (45). The first telescopic device (45) has a switchable follow-up state and a non-follow-up state. In the follow-up state, the first telescopic device (45) follows the change of the distance between the first suspension line (33) and the second suspension line (34). In the non-follow-up state, the first telescopic device (45) is used to actively telescope to adjust the distance between the first counterweight (31) below the first suspension line (33) and the second counterweight (32) below the second suspension line (34) in a direction perpendicular to the amplitude change plane. The second adjusting device (4) also includes a second telescopic device. The second telescopic device is used to telescope to adjust the distance between the first counterweight (31) and the second counterweight (32) and the second end of the boom (12) in a horizontal direction parallel to the amplitude change plane. The second adjusting device (4) includes a first rod (41), a second rod (42), a third rod (43) and a fourth rod (44). The first rod (41) The first end of the first rod (41) and the first end of the second rod (42) are hinged to the chassis (11), the second end of the first rod (41) and the first end of the third rod (43) are hinged, the second end of the third rod (43) is connected to the first suspension line (33), the second end of the second rod (42) and the first end of the fourth rod (44) are hinged, the second end of the fourth rod (44) is connected to the second suspension line (34), the first rod (41) and the second rod (42) are arranged in a V shape, the second end of the first rod (41) and the second rod The second ends of the rods (42) are located on both sides of the amplitude variation plane, and any three of the first rod (41), the second rod (42), the third rod (43) and the fourth rod (44) are not coplanar. The first telescopic device (45) is connected between the first rod (41) and the second rod (42), and the second telescopic device includes a first telescopic member (461) connected between the first rod (41) and the third rod (43) and a second telescopic member (462) connected between the second rod (42) and the fourth rod (44).

2. The crane according to claim 1, wherein: The invention also includes a third telescopic device, which includes a third telescopic member (35) provided between the first counterweight (31) and the first suspension line (33) and a fourth telescopic member (36) provided between the second counterweight (32) and the second suspension line (34). The third telescopic device is configured to: lift the first counterweight (31) and the second counterweight (32) off the ground so that the counterweight group (3) has a fully counterweighted state, or to partially support the weight of the first counterweight (31) and the weight of the second counterweight (32) on the ground so that the counterweight group (3) has a partially counterweighted state.

3. The crane according to claim 1, wherein: The first telescopic device (45) includes a telescopic oil cylinder, which includes a piston rod and a cylinder barrel. The crane also includes a hydraulic system for controlling the telescopic oil cylinder. The hydraulic system is configured to enable the telescopic oil cylinder to have a floating state in which the piston rod can slide freely relative to the cylinder barrel and a controlled state in which the position of the piston rod relative to the cylinder barrel is controlled by pressure oil.

4. The crane according to any one of claims 1 to 3, characterized in that: It also includes a main luffing mast whose first end is connected to the chassis (11), and the second end of the main luffing mast is simultaneously connected to the second end of the first super lifting mast (21) and the second end of the second super lifting mast (22) through a pull plate, and the second end of the main luffing mast is connected by a rope with adjustable length.

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