Expandable counterweight arm structure and crane

Abstract

The utility model relates to the technical field of cranes, in particular to an extensible balance weight arm structure and a crane, the extensible balance weight arm structure comprises a balance weight plate and a balance weight adjusting unit, and the balance weight adjusting unit is arranged at the top or the bottom of the balance weight plate; the counterweight adjusting unit comprises a seat body plate fixedly mounted on the counterweight plate, and a first rotating arm and a second rotating arm are symmetrically arranged on the seat body plate; a driving part is arranged on the seat body plate, is connected with the first rotating arm and the second rotating arm and is used for driving the first rotating arm and the second rotating arm to be close to each other or away from each other; the end of the first rotating arm and the end of the second rotating arm are each connected with a balance weight seat, each balance weight seat comprises a plurality of balance weight blocks, and the balance weight blocks can be mutually overlapped or separated. The problems that a fixed balance weight structure adopted by a traditional crane cannot dynamically adapt to working condition changes, and the stabilizing moment and the overturning moment are prone to dynamic unbalance are solved.

Description

TECHNICAL FIELD

[0001] The utility model relates to a crane technical field, concretely relates to a scalable counterweight arm structure and crane. BACKGROUND

[0002] In the field of building construction, road engineering and emergency rescue, as the key operation equipment, the counterweight adjustment system of the crane is the core guarantee for realizing the mechanical balance of the whole machine, and directly restricts the operation stability, power output and safety performance boundary of the equipment. The traditional crane adopts a fixed counterweight structure, which is statically installed on the rear part of the rotating table through a rigid counterweight seat. Its design needs to strictly meet the stable torque matching requirements and the limit constraint of the rear axle load by the national mandatory standard. However, this mode has significant technical defects: the counterweight space distribution is rigidly coupled with the center of gravity of the whole machine, and cannot be dynamically adjusted with the lifting load quality and operation amplitude, resulting in unbalanced matching of the stable torque and the overturning torque, which not only limits the rated lifting capacity but also increases the overturning risk. With the development of modern engineering towards high altitude and large span (such as super high-rise building construction and large bridge installation) and the improvement of the demand for rapid response in emergency rescue, the rigidity and non-adjustability of the traditional counterweight system have become the core bottleneck restricting the operation efficiency and safety of the crane. For example, in super high-rise construction, the crane needs to frequently adjust the operation amplitude and the lifting weight. The fixed counterweight is difficult to dynamically adapt to the load change, resulting in a sharp fluctuation of the stable torque. In the complex terrain of emergency rescue, the counterweight parameters need to be quickly adjusted to expand the operation range. However, the traditional structure lacks adjustment ability and is difficult to achieve precise control, which is difficult to meet the needs of efficient and safe operation in multiple scenarios.

[0003] Therefore, the inventor proposes a gas-liquid controlled counterweight adjustment structure and crane to solve the above technical problems. CONTENT OF THE UTILITY MODEL

[0004] One of the purposes of the utility model is to provide a scalable counterweight arm structure to solve the problem that the traditional crane adopts a fixed counterweight structure and cannot dynamically adapt to the working condition change, which easily leads to dynamic imbalance of the stable torque and the overturning torque. The second purpose is to propose a crane.

[0005] In order to achieve the above purpose, the utility model adopts the following technical scheme:

[0006] A scalable counterweight arm structure and crane, comprising a counterweight plate and a counterweight adjustment unit, the counterweight adjustment unit is arranged on the top or bottom of the counterweight plate;

[0007] The counterweight adjustment unit comprises a seat plate fixedly installed on the counterweight plate, and the seat plate is symmetrically provided with a first rotating arm and a second rotating arm;

[0008] The seat body plate is provided with a driving member connected with the first rotating arm and the second rotating arm for driving the first rotating arm and the second rotating arm to approach or move away from each other.

[0009] The end of the first rotating arm and the second rotating arm is connected with a counterweight seat, and the counterweight seat comprises a plurality of counterweight blocks which can be overlapped or separated.

[0010] Further, the seat body plate is rotatably connected with two intermeshing driven gears, each of which is connected with an arm rod unit, and the end of the arm rod unit is connected with the counterweight seat.

[0011] Further, the driving member is a motor fixedly arranged at the bottom of the seat body plate, and the output shaft of the motor is connected with a driving shaft penetrating the seat body plate, the driving shaft is coaxially fixedly connected with a driving gear, the driving gear is engaged with one of the driven gears for controlling the opening and closing of the two arm rod units.

[0012] Further, the arm rod unit comprises a first connecting rod fixedly connected with the driven gear and a second connecting rod hingedly connected with the first connecting rod, the end of the second connecting rod is connected with the counterweight seat, and a third connecting rod is hingedly connected to the middle part of the second connecting rod, and the third connecting rod is hingedly connected with the seat body plate.

[0013] Further, the counterweight plate is rotatably connected with a rotating disc coaxially connected with the driving shaft, the rotating disc is eccentrically connected with a driving column, the upper side of the counterweight plate is slidably connected with a sliding frame, the sliding frame is fixedly connected with an annular block, and an annular frame slot is formed in the annular block.

[0014] The driving column extends into the annular frame slot for driving the sliding frame to move.

[0015] Further, it further comprises a counterweight hammer, the counterweight hammer comprises a counterweight box and a sliding plug slidably connected in the counterweight box, the sliding plug divides the inside of the counterweight box into a third gas cavity and a third liquid cavity, and the counterweight plate is fixedly provided with a first adjusting cylinder and a second adjusting cylinder.

[0016] Further, the first adjusting cylinder comprises a first cylinder body and a first sliding plug sealingly and slidably connected with the first cylinder body, the first sliding plug divides the inside of the first cylinder body into a first gas cavity and a first liquid cavity, the first sliding plug is connected with a first connecting column, and the first connecting column extends out of the first cylinder body and is connected with one side of the sliding frame.

[0017] Further, the second adjusting cylinder comprises a second cylinder body and a second sliding plug sealingly connected to the second cylinder body, the second sliding plug divides the inside of the second cylinder body into a second air cavity and a second liquid cavity, a second connecting column is connected to the second sliding plug, and the second connecting column extends out of the second cylinder body and is connected to the other side of the sliding frame.

[0018] Further, a first air pipe is connected between the first air cavity and the third air cavity, and a second air pipe is connected between the second air cavity and the third air cavity.

[0019] A first liquid pipe is connected between the first liquid cavity and the third liquid cavity, and a second liquid pipe is connected between the second liquid cavity and the third liquid cavity.

[0020] In another aspect, the application also provides a crane, which comprises a base, a control console arranged above the base, a supporting table arranged on the control console, a counterweight frame hingedly connected to the supporting table, a counterweight arm hingedly connected to one end of the counterweight frame, and a counterweight weight connected to the other end of the counterweight frame.

[0021] The application has the following beneficial effects:

[0022] The crane provided by the application realizes the double dynamic optimization of the counterweight force arm and the counterweight mass through the mechanical linkage and the hydraulic pneumatic cooperative adjustment mechanism, and when the driving member drives the first rotating arm and the second rotating arm to fold or unfold, not only the radial displacement of the counterweight seat is accurately controlled through the gear meshing and the connecting rod mechanism to adjust the length of the force arm, but also the reciprocating movement of the sliding frame links the adjustment cylinder and the gas-liquid medium exchange in the counterweight weight to dynamically adjust the effective density of the counterweight weight. The cooperative action of the mechanical displacement and the mass change can significantly improve the adjustment range and response efficiency of the anti-overturning moment through the coupling of the lever effect and the fluid volume compensation without increasing or decreasing the counterweight block, so as to meet the multi-working condition requirements of the crane from light load transfer to heavy load operation, and guarantee the real-time and accuracy of the moment balance.

[0023] Other advantages, objects, and features of the application will be set forth in part in the following specification taken in conjunction with the accompanying drawings, and in part will become apparent to those skilled in the art from a consideration of the following specification and drawings, or can be learned from the practice of the application. The advantages of the application can be realized and attained by means of the instrumentalities and combinations pointed out in the following detailed description. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 It is a whole structure schematic view of the expandable counterweight arm structure of the application.

[0025] Figure 2 It is a whole structure schematic view of the expandable counterweight arm structure of the application. Figure 1Split structure schematic diagram of the utility model;

[0026] Figure 3 The utility model expandable counterweight arm structure's structure schematic diagram of the bottom view;

[0027] Figure 4 The utility model expandable counterweight arm structure's structure schematic diagram of the counterweight adjustment unit in the counterweight arm structure is shown in the figure.

[0028] Figure 5 The utility model expandable counterweight arm structure's counterweight principle schematic diagram is shown in the figure.

[0029] Figure 6 The utility model expandable counterweight arm structure's counterweight hammer gas-liquid flow schematic diagram is shown in the figure.

[0030] Figure 7 The utility model expandable counterweight arm structure and the overall structure schematic diagram of the crane is shown in the figure.

[0031] Among them, counterweight plate 1, seat body plate 2, first swing arm 3, second swing arm 4, counterweight seat 5, driven gear 6, drive piece 7, drive shaft 71, drive gear 72, first connecting rod 73, second connecting rod 74, third connecting rod 75, rotating disc 8, drive column 81, sliding frame 82, annular block 83, counterweight hammer 91, counterweight box 911, sliding plug 912, third gas cavity 913, third liquid cavity 914, first adjustment cylinder 92, first cylinder body 921, first sliding plug 922, first gas cavity 923, first liquid cavity 924, first connecting column 925, first gas pipe 926, second gas pipe 927, first liquid pipe 928, second liquid pipe 929, second adjustment cylinder 93, second cylinder body 931, second sliding plug 932, second gas cavity 933, second liquid cavity 934, second connecting column 935, base 10, control cabinet 11, support table 12, counterweight arm 13, counterweight frame 14. DETAILED DESCRIPTION

[0032] The other advantages and effects of the utility model can be easily understood by the person skilled in the art from the content disclosed in the specification. The utility model can also be implemented or applied by another different specific implementation, and each detail in the specification can be modified or changed based on different viewpoints and applications without departing from the spirit of the utility model. It should be understood that the preferred embodiment is only for illustrating the utility model, and is not for limiting the protection scope of the utility model.

[0033] It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. Therefore, the drawings only show the components related to the present invention and are not drawn according to the number, shape and size of the components in actual implementation. In actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0034] This embodiment proposes an scalable counterweight boom structure and crane, such as Figures 1 to 7 As shown, the device includes a counterweight plate 1 and a counterweight adjustment unit, which is disposed at the top or bottom of the counterweight plate 1; in this embodiment, the counterweight adjustment unit is preferably disposed at the bottom of the counterweight plate 1. The counterweight adjustment unit includes a base plate 2 fixedly mounted on the counterweight plate 1, on which a first rotating arm 3 and a second rotating arm 4 are symmetrically arranged; a driving member 7 is disposed on the base plate 2, which is connected to the first rotating arm 3 and the second rotating arm 4, and is used to drive the first rotating arm 3 and the second rotating arm 4 to move closer or further apart; a counterweight seat 5 is connected to the end of each of the first rotating arm 3 and the second rotating arm 4, and the counterweight seat 5 includes a plurality of counterweight blocks, which can be stacked or separated from each other.

[0035] According to the above technical solution, when the crane needs to lift heavy loads, the drive component 7 drives the symmetrically arranged first rotating arm 3 and second rotating arm 4 to move closer to each other and retract, which increases the horizontal distance between the overall center of gravity of the counterweight system and the center of rotation of the crane. According to the lever principle, the counterweight torque (counterweight mass × lever arm length) increases accordingly, forming a longer anti-overturning lever arm, ensuring that the stabilizing torque and overturning torque are always in a dynamic balance state, thereby effectively balancing the overturning torque generated by lifting heavy loads, enhancing the stability of the crane, and realizing dynamic torque matching without adding or removing counterweights.

[0036] In a preferred embodiment, two meshing driven gears 6 are rotatably connected to the base plate 2. Each driven gear 6 is connected to an arm unit, the end of which is connected to the counterweight base 5. The driving component 7 is a motor, which is fixedly mounted at the bottom of the base plate 2. The motor is a forward and reverse motor, and the forward or reverse rotation angle is less than 180 degrees each time the counterweight is adjusted. The output shaft of the motor passes through the base plate 2 and is connected to a drive shaft 71. A drive gear 72 is coaxially fixedly connected to the drive shaft 71, and the drive gear 72 meshes with one of its driven gears 6 to control the opening and closing of the two arm units.

[0037] In a preferred embodiment, the boom unit includes a first connecting rod 73 fixed to the driven gear 6 and a second connecting rod 74 hinged to the first connecting rod 73. The end of the second connecting rod 74 is connected to the counterweight 5, and a third connecting rod 75 is hinged to the middle of the second connecting rod 74, and the third connecting rod 75 is hinged to the base plate 2. In this embodiment, when the motor starts, the drive gear 72 rotates synchronously with the drive shaft 71, driving the driven gear 6 meshing with it to rotate. This, in turn, causes the other driven gear 6 to rotate in the opposite direction through gear meshing. The two driven gears 6 respectively drive the boom units connected to them to swing synchronously in opposite directions. The counterweight 5 connected to the end of the boom unit moves accordingly, realizing the opening and closing action of the two boom units. For example, when reducing the amplitude or lightly loading, the motor drives the boom unit to extend, and the counterweight 5 moves outward to reduce the stabilizing torque; while when increasing the working amplitude or lifting weight, the boom unit retracts. Figure 5 As shown, the weight of the counterweight seat 5 is G, the connection point between the left side of the control seat and the counterweight arm 13 is the fulcrum, and the distance from the fulcrum to the movable hinge point of the counterweight adjustment unit is d. When the crane needs to lift a heavy load, the drive component 7 drives the symmetrically arranged first rotating arm 3 and second rotating arm 4 to move closer to each other and retract, which causes the horizontal distance of the overall center of gravity of the counterweight system relative to the rotation center of the crane to increase, changing from c1 to c2. Under the condition that the weight remains unchanged, the arm length increases, thereby increasing the counterweight torque, thus effectively balancing the overturning torque generated by lifting heavy objects and enhancing the stability of the crane.

[0038] As a preferred embodiment, such as Figure 1 As shown, a rotating disk 8 is rotatably connected to the counterweight plate 1. The rotating disk 8 is coaxially connected to the drive shaft 71. A drive column 81 is eccentrically connected to the rotating disk 8. A sliding frame 82 is slidably connected above the counterweight plate 1. An annular block 83 is fixedly connected to the sliding frame 82. An annular groove is formed inside the annular block 83. The drive column 81 extends into the annular groove to drive the sliding frame 82 to move. The drive shaft 71 synchronously drives the rotating disk 8 to rotate. The eccentrically positioned drive column 81 performs a compound motion along the preset annular groove inside the annular block 83. The sidewall constraint of the annular groove forces the drive column 81 to slide in the groove and push the annular block 83 to move horizontally, thereby driving the sliding frame 82 to perform linear reciprocating motion on the counterweight plate 1.

[0039] In a preferred embodiment, the first regulating cylinder 92 includes a first cylinder body 921 and a first sliding plug 922 that is slidably and sealingly connected to the first cylinder body 921. The first sliding plug 922 divides the interior of the first cylinder body 921 into a first air chamber 923 and a first liquid chamber 924. A first connecting post 925 is connected to the first sliding plug 922, extending out of the first cylinder body 921 and connecting to one side of the sliding frame 82. The second regulating cylinder 93 includes a second cylinder body 931 and a second sliding plug 932 that is slidably and sealingly connected to the second cylinder body 931. The second sliding plug 932 divides the interior of the second cylinder body 931 into a second air chamber 933 and a second liquid chamber 934. A second connecting post 935 is connected to the second sliding plug 932, extending out of the second cylinder body 931 and connecting to the other side of the sliding frame 82. It also includes a counterweight 91, which includes a counterweight box 911 and a sliding plug 912 slidably connected inside the counterweight box 911. The sliding plug 912 divides the interior of the counterweight box 911 into a third air chamber 913 and a third liquid chamber 914. A first adjusting cylinder 92 and a second adjusting cylinder 93 are fixedly installed on the counterweight plate 1. The first adjusting cylinder 92 and the second adjusting cylinder 93 are located on both sides of the sliding frame 82.

[0040] A first air tube 926 connects the first air chamber 923 and the third air chamber 913, and a second air tube 927 connects the second air chamber 933 and the third air chamber 913; a first liquid tube 928 connects the first liquid chamber 924 and the third liquid chamber 914, and a second liquid tube 929 connects the second liquid chamber 934 and the third liquid chamber 914.

[0041] When the sliding frame 82 moves to the left, the first adjusting cylinder 92 and the second adjusting cylinder 93 on both sides drive the first sliding block 922 and the second sliding block 932 to move synchronously within the first cylinder body 921 and the second cylinder body 931 respectively, through the corresponding first connecting column 925 and second connecting column 935. When the crane is lightly loaded or needs to reduce or lower the lifting weight during relocation, the drive component 7 drives the sliding frame 82 to move to the left. Taking the leftward movement of the sliding frame 82 as an example: Figure 6 As shown, the left first slide plug 922 moves left to compress the gas in the first gas chamber 923, and the gas is injected into the third gas chamber 913 of the counterweight 91. Simultaneously, the liquid in the third liquid chamber 914 is pushed into the first liquid chamber 924 and the second liquid chamber 934. The right second slide plug 932 moves left to compress the gas in the second gas chamber 933, and the gas is injected into the third gas chamber 913. This process, through the gas volume expansion and liquid compensation mechanism, reduces the total amount of liquid and increases the total amount of gas in the counterweight 91, thereby reducing the effective density of the counterweight 91. Combined with the horizontal displacement of the sliding frame 82, a dual counterweight adjustment effect is formed, realizing the coordinated control of the counterweight displacement and the mass change of the counterweight 91, and dynamically optimizing the torque balance of the whole machine.

[0042] In another aspect, the application also provides a crane, comprising a base 10, a control console 11 arranged above the base 10, a support table 12 arranged on the control console 11, a counterweight frame 14 hingedly connected to the support table 12, a counterweight arm 13 hingedly connected to one end of the counterweight frame 14, and a counterweight 91 connected to the other end of the counterweight frame 14; further comprising the expandable counterweight arm 13 structure as described above, and the counterweight plate 1 is fixedly arranged on the side of the control console 11 away from the crane arm.

[0043] The above embodiments are only preferred embodiments for fully illustrating the present application, and the protection scope of the present application is not limited thereto. Any equivalent substitutions or transformations made by those skilled in the art based on the present application are within the protection scope of the present application.

Claims

1. An expandable counterweight arm structure, characterized by, The utility model relates to a counterweight plate (1) and counterweight adjusting unit, the counterweight adjusting unit sets up at the top or bottom of counterweight plate (1), the counterweight adjusting unit includes the seat body board (2) fixedly installed on the counterweight plate (1), the seat body board (2) is provided with the first swing arm (3) and the second swing arm (4) on the symmetry, the seat body board (2) is provided with drive part (7), drive part (7) is connected with the first swing arm (3) and the second swing arm (4), is used for driving the first swing arm (3) and the second swing arm (4) mutually close or away, the end of first swing arm (3) and second swing arm (4) is connected with the counterweight seat (5), and the counterweight seat (5) includes a plurality of counterweight blocks, and each counterweight block can mutually superpose or separate. The utility model relates to a counterweight plate (1) and counterweight adjusting unit, the counterweight adjusting unit sets up at the top or bottom of counterweight plate (1), the counterweight adjusting unit includes the seat body board (2) fixedly installed on the counterweight plate (1), the seat body board (2) is provided with the first swing arm (3) and the second swing arm (4) on the symmetry, the seat body board (2) is provided with drive part (7), drive part (7) is connected with the first swing arm (3) and the second swing arm (4), is used for driving the first swing arm (3) and the second swing arm (4) mutually close or away, the end of first swing arm (3) and second swing arm (4) is connected with the counterweight seat (5), and the counterweight seat (5) includes a plurality of counterweight blocks, and each counterweight block can mutually superpose or separate. The utility model discloses a counterweight plate (1) and counterweight adjusting unit, the counterweight adjusting unit sets up at the top or bottom of counterweight plate (1), the counterweight adjusting unit includes the seat body board (2) fixedly installed on the counterweight plate (1), the seat body board (2) is provided with the first swing arm (3) and the second swing arm (4) on the symmetry, the seat body board (2) is provided with drive part (7), drive part (7) is connected with the first swing arm (3) and the second swing arm (4), is used for driving the first swing arm (3) and the second swing arm (4) mutually close or away, the end of first swing arm (3) and second swing arm (4) is connected with the counterweight seat (5), and the counterweight seat (5) includes a plurality of counterweight blocks, and each counterweight block can mutually superpose or separate. The utility model discloses a counterweight plate (1) and counterweight adjusting unit, the counterweight adjusting unit sets up at the top or bottom of counterweight plate (1), the counterweight adjusting unit includes the seat body board (2) fixedly installed on the counterweight plate (1), the seat body board (2) is provided with the first swing arm (3) and the second swing arm (4) on the symmetry, the seat body board (2) is provided with drive part (7), drive part (7) is connected with the first swing arm (3) and the second swing arm (4), is used for driving the first swing arm (3) and the second swing arm (4) mutually close or away, the end of first swing arm (3) and second swing arm (4) is connected with the counterweight seat (5), and the counterweight seat (5) includes a plurality of counterweight blocks, and each counterweight block can mutually superpose or separate. The utility model discloses a counterweight plate (1) and counterweight adjusting unit, the counterweight adjusting unit sets up at the top or bottom of counterweight plate (1), the counterweight adjusting unit includes the seat body board (2) fixedly installed on the counterweight plate (1), the seat body board (2) is provided with the first swing arm (3) and the second swing arm (4) on the symmetry, the seat body board (2) is provided with drive part (7), drive part (7) is connected with the first swing arm (3) and the second swing arm (4), is used for driving the first swing arm (3) and the second swing arm (4) mutually close or away, the end of first swing arm (3) and second swing arm (4) is connected with the counterweight seat (5), and the counterweight seat (5) includes a plurality of counterweight blocks, and each counterweight block can mutually superpose or separate.

2. The expandable weight arm structure of claim 1, wherein: The utility model discloses a counterweight plate (1) and counterweight adjusting unit, the counterweight adjusting unit sets up at the top or bottom of counterweight plate (1), the counterweight adjusting unit includes the seat body board (2) fixedly installed on the counterweight plate (1), the seat body board (2) is provided with the first swing arm (3) and the second swing arm (4) on the symmetry, the seat body board (2) is provided with drive part (7), drive part (7) is connected with the first swing arm (3) and the second swing arm (4), is used for driving the first swing arm (3) and the second swing arm (4) mutually close or away, the end of first swing arm (3) and second swing arm (4) is connected with the counterweight seat (5), and the counterweight seat (5) includes a plurality of counterweight blocks, and each counterweight block can mutually superpose or separate.

3. The expandable weight arm structure of claim 2, wherein: ​ 4. The expandable weight arm structure of claim 3, wherein: ​ 5. The expandable weight arm structure of claim 4, wherein: ​ ​ 6. The expandable weight arm structure of claim 5, wherein: ​ 7. The expandable weight arm structure of claim 6, wherein: The first adjusting cylinder (92) comprises a first cylinder body (921) and a first sliding plug (922) sealingly and slidably connected to the first cylinder body (921), the first sliding plug (922) divides the inside of the first cylinder body (921) into a first air cavity (923) and a first liquid cavity (924), the first sliding plug (922) is connected with a first connecting column (925), the first connecting column (925) extends out of the first cylinder body (921) and is connected to one side of the sliding frame (82).

8. The expandable weight arm structure of claim 7, wherein: The second adjusting cylinder (93) comprises a second cylinder body (931) and a second sliding plug (932) sealingly and slidably connected to the second cylinder body (931), the second sliding plug (932) divides the inside of the second cylinder body (931) into a second air cavity (933) and a second liquid cavity (934), the second sliding plug (932) is connected with a second connecting column (935), the second connecting column (935) extends out of the second cylinder body (931) and is connected to the other side of the sliding frame (82).

9. The expandable weight arm structure of claim 8, wherein: The first air cavity (923) and the third air cavity (913) are connected by a first air pipe (926), the second air cavity (933) and the third air cavity (913) are connected by a second air pipe (927); The first liquid cavity (924) and the third liquid cavity (914) are connected by a first liquid pipe (928), the second liquid cavity (934) and the third liquid cavity (914) are connected by a second liquid pipe (929).

10. A crane, characterized in that The weight arm structure comprises a base (10), a control console (11) arranged above the base (10), a support table (12) arranged on the control console (11), a counterweight frame (14) hingedly connected to the support table (12), a counterweight arm (13) hingedly connected to one end of the counterweight frame (14), and a counterweight (91) connected to the other end of the counterweight frame (14). The weight arm structure according to any one of claims 1 to 9 is arranged on the side of the control console (11) away from the counterweight arm (13), and the counterweight plate (1) is fixedly arranged on the control console (11).

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