Crane

Abstract

The present invention discloses a crane, comprising: a chassis; a slewing platform rotatably provided on the chassis; a main boom including a first end hinged to a first end of the slewing platform and a second end for lifting heavy objects; a mast for luffing the main boom, a first end of the mast being hinged to the first end of the slewing platform, and a second end of the mast being connected to the second end of the main boom and a second end of the slewing platform; a first independent counterweight system including a first independent counterweight and a connection structure connected between the first independent counterweight and the slewing platform, the connection structure being configured to enable the first independent counterweight to have a partial working state, in which partial working state, the first independent counterweight is supported on the ground and the weight of the first independent counterweight is jointly supported by the ground and the slewing platform.

Description

Technical Field

[0001] The present invention relates to a construction machinery, and particularly to a crane. Background Art

[0002] A crane, also known as a hoist, is a multi-action lifting machine that vertically lifts and horizontally transports heavy objects within a certain range. The crane uses a hook to vertically lift heavy objects by raising and lowering the main boom (also known as the lifting boom). The heavy object is horizontally moved by the slewing motion of the slewing platform or the traveling of the whole machine. In order to prevent the crane from tipping over under the action of the gravity of the main boom and the heavy object when lifting the heavy object, or to prevent the crane from tipping over under the action of the self-weight of the main boom when the main boom is gradually pulled up from the ground, a counterweight is provided on the slewing platform of the crane to overcome the tipping moment generated by the gravity of the heavy object and the main boom during lifting, or to overcome the tipping moment generated by the gravity of the main boom when the main boom is pulled up. However, the supporting capacity of the slewing platform on the crane and the slewing bearing structure supporting the slewing platform is limited. In order to improve the lifting capacity of the crane, setting too many counterweights on the slewing platform will cause an excessive working load on the slewing platform or the slewing bearing structure, and even cause damage to the structural members. Summary of the Invention

[0003] The present invention discloses a crane, comprising:

[0004] A chassis;

[0005] A slewing platform rotatably provided on the chassis, comprising opposite first and second ends;

[0006] A main boom, comprising a first end hinged to the first end of the slewing platform and a second end for lifting heavy objects;

[0007] A mast for luffing the main boom, a first end of the mast being hinged to the first end of the slewing platform, and a second end of the mast being connected to the second end of the main boom and the second end of the slewing platform;

[0008] A first independent counterweight system, comprising a first independent counterweight and a connection structure connected between the first independent counterweight and the second end of the slewing platform, the connection structure being configured to enable the first independent counterweight to have a partial working state, in which the first independent counterweight is supported on the ground and the weight of the first independent counterweight is jointly supported by the ground and the slewing platform.

[0009] In some embodiments, the connection structure comprises a first lifting device for lifting and lowering the first independent counterweight to enable the first independent counterweight to be supported on the ground or to be disengaged from the ground.

[0010] In some embodiments, the crane further includes a fixed counterweight fixedly disposed on the slewing platform, and the first independent counterweight is detachably connected to the slewing platform.

[0011] In some embodiments, the first independent counterweight is detachably connected to the slewing platform, and the crane further includes:

[0012] A fixed counterweight fixedly disposed on the slewing platform;

[0013] A force sensor disposed between the second end of the mast and the second end of the main boom for detecting the pulling force of the main boom on the mast; and

[0014] A control system signal-connected to the force sensor and the first lifting device, the control system being configured to: control the first lifting device to lift or lower the first independent counterweight according to the detection result of the force sensor.

[0015] In some embodiments, the first independent counterweight system includes a first connecting frame connecting the slewing platform and the connecting structure, and the first connecting frame extends in a direction away from the first end of the slewing platform.

[0016] In some embodiments, the first connecting frame includes a first telescopic mechanism disposed between the connecting structure and the slewing platform, and the first telescopic mechanism is configured to drive the first independent counterweight to approach or move away from the first end of the slewing platform.

[0017] In some embodiments, the crane further includes:

[0018] An extended boom, with its first end hinged to the first end of the slewing platform and its second end connected to the second ends of the main boom and the mast; and

[0019] A second independent counterweight system, including a second independent counterweight, a second lifting device connected between the second independent counterweight and the second end of the extended boom, and a second connecting frame connected between the second end of the slewing platform and the second lifting device, the second lifting device being configured to lift or lower the second independent counterweight so that the second independent counterweight is supported on the ground or disengaged from the ground.

[0020] In some embodiments, the second connecting frame includes a second telescopic mechanism configured to drive the second independent counterweight to approach or move away from the first end of the slewing platform.

[0021] In some embodiments, the crane includes a fixed counterweight fixedly disposed at the second end of the slewing platform, and the second independent counterweight is detachably connected to the slewing platform.

[0022] Based on the crane provided by the present invention, by setting up the first independent counterweight system, connecting the first independent counterweight to the slewing platform through the first independent counterweight and the connection structure, and enabling the first independent counterweight to have partial working states, the first independent counterweight can be set on the ground. While being able to play the role of stabilizing the crane by the first independent counterweight to prevent the crane from tipping over, it can reduce the load on the slewing platform and the slewing bearing structure supporting the slewing platform, which is beneficial to improving the working condition environment of the slewing platform and the slewing bearing structure, reducing the damage of the slewing platform or the slewing bearing, and increasing the working life of the slewing platform and the slewing bearing structure. The first independent counterweight can play a stabilizing role for the crane in both the superlift condition with a superlift device and the standard condition without a superlift device of the crane.

[0023] Other features and advantages of the present invention will become clear through the following detailed description of the exemplary embodiments of the present invention with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The drawings described herein are used to provide a further understanding of the present invention, and form a part of this application. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention. In the drawings:

[0025] Figure 1 is a schematic structural diagram of the crane according to the embodiment of the present invention;

[0026] Figure 2 is a schematic structural diagram of the crane according to another embodiment of the present invention;

[0027] Figure 3 is a schematic structural diagram of the crane according to still another embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0028] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and in no way limits the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present invention.

[0029] Unless otherwise specifically stated, the relative arrangements, numerical expressions, and numerical values of the components and steps set forth in these embodiments do not limit the scope of the present invention. At the same time, it should be understood that, for the sake of convenience of description, the dimensions of the various parts shown in the drawings are not drawn in actual proportional relationships. Technologies, methods, and devices known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, the said technologies, methods, and devices should be regarded as part of the authorization specification. In all the examples shown and discussed here, any specific values should be construed as merely exemplary and not as a limitation. Therefore, other examples of the exemplary embodiments may have different values. It should be noted that like reference numerals and letters denote like items in the following drawings, and thus, once an item is defined in one drawing, it does not need to be further discussed in subsequent drawings.

[0030] For the sake of convenience of description, spatial relative terms such as "above", "over", "on the upper surface", "upper", etc. may be used here to describe the spatial positional relationship of a device or feature shown in the drawing with other devices or features. It should be understood that the spatial relative terms are intended to encompass different orientations in use or operation in addition to the orientation depicted in the drawing of the device. For example, if the device in the drawing is inverted, the device described as "above" or "over" other devices or structures will then be positioned "below" or "beneath" the other devices or structures. Thus, the exemplary term "above" can include both the orientations of "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and corresponding interpretations will be made for the spatial relative descriptions used here.

[0031] As Figures 1 to 3 shown, the crane of this embodiment includes a chassis 1, a slewing platform 22, a main boom 3, a mast 4, and a first independent counterweight system.

[0032] The slewing platform 22 is rotatably provided on the chassis 1 and includes opposite first and second ends; the slewing platform 22 is supported on the chassis 1 through a slewing bearing structure 21, and the slewing bearing structure 21 can be a slewing motor, an electric motor, or other structures for driving the slewing platform 22 to rotate relative to the chassis 1. The chassis 1 can be a mobile chassis, such as a crawler chassis, a wheeled chassis, etc., and in this case, the crane is a mobile crane. The chassis 1 can also be a stationary chassis, that is, in this case, the crane is a non-mobile crane.

[0033] The main boom 3 includes a first end hinged to the first end of the slewing platform 22 and a second end for lifting heavy objects. The main boom 3 is hinged to the first end of the slewing platform 22 through its first end, so that it can rotate relative to the slewing platform 22 for luffing. The second end of the main boom 3 is used to support the lifting of heavy objects by the hook.

[0034] The first end of the mast 4 is hinged to the slewing platform 22, and the second end is connected to the second end of the main boom 3 for luffing the main boom 3. In a crane without a superlift device, as Figure 1 and Figure 2 shown, the second end of the mast 4 is directly connected to the second end of the main boom 3 through a tension plate, a cable, etc. In a crane with a superlift device, as Figure 3 shown, the second end of the mast 4 is connected to the second end of the superlift boom 8 through a cable, a tension plate, etc., and then connected between the second end of the superlift boom 8 and the second end of the main boom, so that the connection between the mast 4 and the second end of the main boom 3 is indirect.

[0035] The first independent counterweight system includes a first independent counterweight 72 and a connection structure connected between the first independent counterweight 72 and the slewing platform 22. The connection structure is configured to enable the first independent counterweight 72 to have a partial working state. In the partial working state of the first independent counterweight 72, the first independent counterweight 72 is supported on the ground and the weight of the first independent counterweight 72 is jointly supported by the ground and the slewing platform. The first independent counterweight 72 can be composed of a plurality of counterweight blocks and a counterweight tray 71 carrying the plurality of counterweight blocks as shown in the figure.

[0036] The connection structure is connected between the first independent counterweight 72 and the slewing platform 22, that is, the connection structure can be directly connected to the slewing platform 22 or can be connected to the slewing platform 22 through other devices. When the first independent counterweight 72 is in the partial working state, the weight of the first independent counterweight 72 is jointly supported by the ground and the slewing platform, that is, at this time, the first independent counterweight 72 is suspended on the slewing platform through the connection structure, and a part of the weight of the first independent counterweight 72 exerts a force on the slewing platform through the connection structure, preventing the crane from tipping over when lifting a relatively heavy object and making the crane stable. The remaining part of the weight of the first independent counterweight 72 is supported by the ground. At this time, as the weight of the heavy object lifted by the crane increases, before the first independent counterweight 72 completely leaves the ground, the anti-tipping force exerted by the first independent counterweight 72 on the slewing platform can increase as the weight of the heavy object increases. When the first independent counterweight 72 is supported on the ground and the crane does not lift a heavy object or lifts a relatively light heavy object, the weight of the first independent counterweight 72 can be fully applied to the ground without exerting pressure on the slewing platform and the slewing bearing structure 21 supporting the slewing platform 22, reducing the load on the slewing bearing structure 21.

[0037] In the crane of this embodiment, by providing a first independent counterweight system and a connection structure, the first independent counterweight 72 can be in a partial working state. The first independent counterweight 72 can be placed on the ground, so that during the main boom assembly process or when the crane does not lift heavy objects, no force is exerted on the slewing platform 22 and the slewing bearing structure 21. Or when lifting relatively light heavy objects, by making the first independent counterweight 72 in a partial working state, only a part of its weight forms a load on the slewing platform and the slewing bearing structure 21 and exerts a force. While being able to play the role of stabilizing the crane by the first independent counterweight 72 to prevent the crane from tipping over, it can reduce the load on the slewing platform and the slewing bearing structure 21 that supports the slewing platform 22, reduce the high-load working condition time of the slewing platform 22 and the slewing bearing structure 21, reduce the damage of the slewing platform and the slewing bearing structure components, and improve the working life of the slewing platform and the slewing bearing structure 21. The first independent counterweight can play a stabilizing role for the crane in both the superlift working condition with a superlift device and the standard working condition without a superlift device of the crane.

[0038] In some embodiments, the connection structure includes a first lifting device 73, and the first lifting device 73 is used to lift and lower the first independent counterweight 72 so that the first independent counterweight 72 is supported on the ground or lifted off the ground, that is, lifted above the ground.

[0039] The first lifting device 73 can lift the first independent counterweight 72 into the air or place the first independent counterweight 72 on the ground. When the first independent counterweight 72 is placed on the ground and the crane does not lift a heavy load or lifts a relatively light load, the weight of the first independent counterweight 72 can be fully applied to the ground without exerting pressure on the slewing platform and the slewing bearing structure 21 that supports the slewing platform 22, reducing the load on the slewing bearing structure 21. When the crane lifts a relatively heavy load and the first independent counterweight 72 is required to exert a stabilizing effect on the crane, the first lifting device 73 can apply a lifting force to the first independent counterweight 72 to enable force transmission between the first independent counterweight 72 and the first lifting device 73. Thus, the first independent counterweight 72 can partially or fully apply its weight to the slewing platform 22 and the slewing bearing 21. When the first independent counterweight 72 exerts a stabilizing effect on the crane, the first independent counterweight 72 can fully function (the first independent counterweight is off the ground) or partially function (the first independent counterweight does not leave the ground). When it does not leave the ground, part of the weight of the first independent counterweight 72 acts on the ground and part acts on the crane. When the first independent counterweight 72 exerts a stabilizing effect, the weight it exerts on the crane is all transmitted to the slewing bearing structure 21 through the slewing platform 22, becoming the load on the slewing platform and the slewing bearing structure 21. When the first lifting device 73 lifts the first independent counterweight 72 above the ground, that is, when the first independent counterweight 72 is suspended, the weight of the first independent counterweight 72 acts entirely on the crane, and the stabilizing effect that can be exerted is the highest. At this time, the crane can lift a relatively heavy load, the slewing platform 22 can slewing, or when the crane is a mobile crane, the crane can also carry the heavy load and the first independent counterweight 72 and move. In this embodiment, by setting the first lifting device 73 to lift and lower, the first independent counterweight 72 can be placed on the ground, so that during the main boom assembly process or when the crane does not lift a heavy load, no force is exerted on the slewing platform 22 and the slewing bearing structure 21, or when lifting a relatively light load, by keeping the first independent counterweight 72 on the ground, only part of its weight forms a load on the slewing platform and the slewing bearing structure 21 and exerts a force. At the same time, when it is necessary to slewing the lifted heavy load, the first lifting device 73 can lift the first independent counterweight 72 above the ground, so that the slewing platform 22 can be slewed conveniently.

[0040] In some embodiments, the crane further includes a fixed counterweight 6 disposed on the slewing platform 22, and the first independent counterweight 72 is detachably connected to the slewing platform 22. The detachable connection between the first independent counterweight 72 and the slewing platform 22 can be achieved by detachably connecting the first independent counterweight 72 to the first lifting device 73, or by detachably connecting between the connecting structure and the slewing platform 22, so as to realize the detachable connection between the first independent counterweight 72 and the slewing platform 22. In this embodiment, the crane can have multiple lifting capacities and adapt to various working environments. When the crane is applied to the working condition of lifting relatively light or heavy objects, or when the main boom has a shorter length, the first independent counterweight 72 can be separated from the slewing platform 22 and removed, so that the fixed counterweight 6 can be used to conveniently lift, slewing, move and other operations on relatively light or heavy objects. When the crane is applied to the working condition of lifting relatively heavy objects, or when the main boom has a longer length, the first independent counterweight 72 can be connected to the slewing platform 22. Under the combined action of the first independent counterweight 72 and the fixed counterweight 6, the crane has a greater lifting capacity.

[0041] In some embodiments, the first independent counterweight 72 is detachably connected to the slewing platform. The crane further includes a fixed counterweight 6 disposed on the slewing platform 22. A force sensor 5 for detecting the tension of the main boom 3 on the mast 4 is provided between the second end of the mast 4 and the second end of the main boom 3. The crane further includes a control system that is signal-connected to the force sensor 5 and the first lifting device 73. The control system is configured to: control the first lifting device 73 to lift or lower the first independent counterweight 72 according to the detection result of the force sensor 5. When the crane hoists a heavy object, the greater the weight of the heavy object, or when the crane extends its boom, the greater the length of the main boom, the greater the tension between the second end of the mast 4 and the second end of the main boom 3, and the greater the moment that may cause the crane to overturn, so the greater the stabilizing effect of the counterweight is required. By setting the force sensor 5, the magnitude of the stabilizing effect and the stabilizing moment that the counterweight needs to exert to ensure that the crane does not overturn can be judged by measuring the magnitude of the tension. In this embodiment, by setting the force sensor 5, during the process of lifting the heavy object, before the heavy object is completely lifted, as the heavy object is gradually lifted, the control system can judge according to the measurement result of the force sensor 5 whether it is necessary to exert the function of the first independent counterweight 72 in addition to the fixed counterweight. And when it is judged that it is necessary to exert the function of the first independent counterweight 72, as the heavy object is gradually lifted, the first lifting device 73 can gradually lift the first independent counterweight 72 in a matching manner, so that the process of the first independent counterweight 72 gradually leaving the ground matches the process of the heavy object being gradually lifted, thereby improving the stability of the crane during the process of lifting the heavy object.

[0042] In some embodiments, such as Figure 2 and Figure 3As shown, the first independent counterweight system includes a first connecting frame 74 that connects the slewing platform 22 and the first lifting device 73. The first connecting frame 74 extends in a direction away from the first end of the slewing platform 22. The first lifting device 73 can be a telescopic oil cylinder, a rope arrangement, or other devices with lifting functions. The first connecting frame 74 extends in a direction away from the first end of the slewing platform 22. When the first independent counterweight 72 is connected to the first connecting frame 74, when the first independent counterweight 72 plays a role in stabilizing the crane, the lever arm size of the anti-overturning moment provided by the first independent counterweight 72 can be increased, so that the weight of the first independent counterweight 72 can be reduced in the structural design.

[0043] In some embodiments, the first connecting frame 74 includes a first telescopic mechanism provided between the lifting mechanism and the slewing platform 22. The first telescopic mechanism is used to drive the first independent counterweight 72 to approach or move away from the first end of the slewing platform. In this embodiment, by providing the first telescopic mechanism, the length of the first connecting frame 74 extending in a direction away from the first end of the slewing platform 22 can be adjusted, so that the lever arm size of the first independent counterweight 72 when it stabilizes the crane can be adjusted.

[0044] In some embodiments, as Figure 3 shown, the crane further includes a superlift boom 8 and a second independent counterweight system.

[0045] The first end of the superlift boom 8 is hinged to the slewing platform 22, and the second end is connected to the second end of the main boom 3; the first end of the mast 4 is hinged to the first end of the slewing platform 22, and the second end is connected to the second end of the superlift boom 8; the second independent counterweight system includes a second independent counterweight 91, a second lifting device 92 that connects the second independent counterweight 91 and the second end of the superlift boom 8, and a second connecting frame 93 that is connected between the second end of the slewing platform 22 and the second lifting device 92. The second lifting device 92 is used to lift and lower the second independent counterweight 91 so that the second independent counterweight 91 is supported on the ground or separated from the ground. The second lifting device 92 is connected to the second end of the superlift boom 8 through structures such as a pull plate and a cable. Similar to the lifting effect of the first lifting device 73 on the first independent counterweight 72, when the second lifting device 92 lifts the second independent counterweight to be suspended in the air, the weight of the second independent counterweight 91 acts entirely on the crane, and the stabilizing effect of the second independent counterweight 91 can be maximized. In addition, by providing the second connecting frame 93, the lever arm of the second independent counterweight 91 when it stabilizes the crane can be effectively increased, which helps to reduce the weight of the second independent counterweight 91. At the same time, by setting the independent counterweight system below the superlift boom 8, the force-bearing environment of the second connecting frame 93 can also be improved. In this embodiment, by providing the second independent counterweight system, the lifting capacity of the crane can be more effectively improved.

[0046] In some embodiments, the second connecting frame 93 includes a second telescoping mechanism configured to drive the second independent counterweight 91 closer to or farther from the first end of the slewing platform. By providing the second telescoping mechanism, the moment arm of the second independent counterweight 91 when it stabilizes the crane can be adjusted. The second telescoping mechanism can be similar to the first telescoping mechanism and include telescopic cylinders, linear motors, and other telescopic devices.

[0047] In some embodiments, the crane further includes a fixed counterweight 6 provided on the slewing platform 22. The first independent counterweight 72 and the second independent counterweight 91 are both detachably connected to the slewing platform 22. A force sensor 5 for detecting the tension of the main boom 3 on the mast 4 is provided between the second end of the mast 4 and the second end of the luffing jib 8. The crane further includes a control system that is signal-connected to the force sensor 5, the first lifting device 73, and the second lifting device. The control system is configured to: control the lifting of the first independent counterweight 72 by the first lifting device 73 and control the lifting of the second independent counterweight 91 by the second lifting device according to the detection result of the force sensor 5. The first independent counterweight 72 and the second independent counterweight 91 are both detachably connected to the slewing platform 22. Thus, by combining the detachable connections of the first independent counterweight 72 and the second independent counterweight 91 with the slewing platform 22, the crane can have multiple lifting capacities and be suitable for more working conditions. By providing the force sensor 5, the lifting of the first independent counterweight 72 and the second independent counterweight 91 can be more matched with the process of the crane lifting a heavy object.

[0048] In some examples, the first independent counterweight 72 is always set on the ground, and the connecting structure can be designed as non-telescopic structural components such as chains and connecting plates, and the first independent counterweight 72 cannot leave the ground actively. At this time, the first independent counterweight 72 can still have partial working states and can still improve the stability of the crane and reduce the load on the slewing platform, and the structure is simpler. The first independent counterweight can play a stabilizing role for the crane in both the luffing jib working condition with a luffing jib device and the standard working condition without a luffing jib device of the crane.

[0049] In some embodiments, the control system described above can be a general-purpose processor, a programmable logic controller (PLC), a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, or any suitable combination thereof for performing the functions described in the present invention.

[0050] 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 them; although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that it is still possible to modify the specific implementation manners of the present invention or perform equivalent replacements for some technical features; without departing from the spirit of the technical solutions of the present invention, they should all be covered within the scope of the technical solutions claimed in the present invention.

Claims

1. A crane, characterized in that, Comprising: Chassis (1); Rotating platform (22), rotatably arranged on the chassis (1), including opposite first and second ends; Main boom (3), including a first end hinged to the first end of the rotating platform (22) and a second end for lifting heavy objects; Mast (4), for luffing the main boom (3), the first end of the mast (4) is hinged to the first end of the rotating platform (22), and the second end of the mast (4) is connected to the second end of the main boom (3) and the second end of the rotating platform (22); First independent counterweight system, including a first independent counterweight (72) and a connection structure connected between the first independent counterweight (72) and the second end of the rotating platform (22), the connection structure is configured to enable the first independent counterweight (72) to have a partial working state, in the partial working state, the first independent counterweight (72) is supported on the ground and the weight of the first independent counterweight (72) is jointly supported by the ground and the rotating platform, the connection structure includes a first lifting device (73), the first lifting device (73) is used to lift and lower the first independent counterweight (72) so that the first independent counterweight (72) is supported on the ground or separated from the ground, the first independent counterweight system includes a first connection frame (74) connecting the rotating platform (22) and the connection structure, and the first connection frame (74) extends in a direction away from the first end of the rotating platform (22); Superlift boom (8), the first end is hinged to the first end of the rotating platform (22), and the second end is connected to the second ends of the main boom (3) and the mast (4); and Second independent counterweight system, including a second independent counterweight (91), a second lifting device (92) connected between the second independent counterweight (91) and the second end of the superlift boom (8), and a second connection frame (93) connected between the second end of the rotating platform (22) and the second lifting device (92), the second lifting device (92) is used to lift and lower the second independent counterweight (91) so that the second independent counterweight (91) is supported on the ground or separated from the ground.

2. The crane according to claim 1, characterized in that, The crane further includes a fixed counterweight (6) fixedly arranged on the rotating platform (22), and the first independent counterweight (72) is detachably connected to the rotating platform (22).

3. The crane according to claim 1, characterized in that The first independent counterweight (72) is detachably connected to the rotating platform (22), and the crane further includes: Fixed counterweight (6), fixedly arranged on the rotating platform (22); Force sensor (5), arranged between the second end of the mast (4) and the second end of the main boom (3), for detecting the tensile force of the main boom (3) on the mast (4); and Control system, signal-connected to the force sensor (5) and the first lifting device (73), the control system is configured to: control the first lifting device (73) to lift and lower the first independent counterweight (72) according to the detection result of the force sensor (5).

4. The crane according to claim 1, characterized in that, The first connecting frame (74) includes a first telescopic mechanism disposed between the connecting structure and the slewing platform (22), and the first telescopic mechanism is configured to drive the first independent counterweight (72) to approach or move away from the first end of the slewing platform (22).

5. The crane according to claim 1, wherein The second connecting frame (93) includes a second telescopic mechanism, and the second telescopic mechanism is configured to drive the second independent counterweight (91) to approach or move away from the first end of the slewing platform (22).

6. The crane according to claim 1, characterized in that, The crane includes a fixed counterweight (6) fixedly disposed at the second end of the slewing platform (22), and the second independent counterweight (91) is detachably connected to the slewing platform (22).

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