Bucket rod and engineering machinery
By introducing a combined connection structure of a central body and peripheral stiffeners into the boom, the problem of insufficient boom stiffness and strength is solved, achieving more uniform force flow transmission and higher resistance to bending and torsion, thus improving the overall performance of the boom.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-18
- Publication Date
- 2026-03-31
AI Technical Summary
The existing sticks in excavators lack sufficient rigidity and strength, making them unable to effectively adapt to complex working conditions. In particular, they are prone to local buckling and uneven stress when subjected to complex alternating loads.
The structure employs a combination of a central body and peripheral stiffeners. These stiffeners are welded to the upper/lower flanges, left/right webs, and rear support of the boom body, forming a stable triangular zone. This enhances the connection area, evenly transmits force flow, and avoids stress concentration.
It significantly improves the overall stiffness and strength of the boom, optimizes the force transmission path, enhances bending and torsional resistance, reduces the probability of fatigue failure, and improves adaptability to complex working conditions.
Smart Images
Figure CN224063543U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of engineering machinery technology, and in particular to a boom and engineering machinery. Background Technology
[0002] The stick is a crucial component of the excavator's working device system. Its front end is hinged to the bucket via a connecting rod assembly, and its rear end is hinged to the boom, resulting in numerous hinge holes. Furthermore, the stick cylinder and bucket cylinder are directly hinged to it. During excavation operations, the hydraulic forces output by these cylinders act directly on these hinge holes. Consequently, the stick experiences significant impact and damage, with the supports, lugs, and dovetail joints at the hinge hole locations being particularly affected.
[0003] Most existing booms adopt a box-shaped structure. The left and right web plates are mostly made of thin and thick plates butt-welded together. The web plate at the hinge hole location is made of thick plate, while the middle low-stress area is made of thin plate, thus balancing the relationship between structural weight and structural strength. The ear plates are mostly made of thick plate and supplemented with inner side plates. The cavity is usually equipped with reinforcing ribs, which are welded and fixed to the upper flange, lower flange, rear support, and left / right web plates. See also Figure 1 The component numbers and names of the existing boom structure are as follows: Existing upper wing plate (20), existing upper ear plate front dovetail (30), existing upper ear plate (40), existing upper ear plate rear dovetail (50), existing rear ear plate (60), existing rear sealing plate (70), existing rear support (80), existing internal reinforcing rib plate (90), existing lower ear plate rear dovetail (100), existing lower ear plate (110) (Note: conventional booms do not have this ear plate), existing lower ear plate front dovetail (120), existing lower wing plate (130), existing web plate (140) (Note: generally left / right web plate assembly), existing middle support (150), existing front support (160).
[0004] Note: Generally, standard booms do not have lower lugs; however, to achieve specific attachment functions, special booms require lower lugs on the lower flanges to house the luffing cylinders that perform these functions. (This is based on...) Figure 1 Characterizes existing boom structures of both conventional and special types.
[0005] Based on the above information regarding the connection function and stress conditions of the boom, as well as the existing structural form of the boom with a single internal reinforcing rib (i.e., the existing internal reinforcing rib (90)), its inherent disadvantages are as follows:
[0006] 1. Structural strength: A single reinforcing plate can lead to uneven stress distribution, especially when the working device is subjected to a combination of eccentric and lateral loads, which can easily cause premature failure of the unreinforced areas.
[0007] 2. Structural buckling: The overlap between the single reinforcing plate and the upper flange and rear support is a line-to-surface contact with a small contact area. When the stick is subjected to bending and torsional loads, it cannot effectively suppress buckling deformation, resulting in a high risk of local buckling.
[0008] 3. In terms of adaptability to working conditions: A single reinforcing plate cannot cope with complex and variable loads, such as lateral impacts or alternating bending moments. Utility Model Content
[0009] The purpose of this utility model is to provide a stick and engineering machinery to solve the problems of weak rigidity and strength, poor adaptability to complex working conditions, and poor ability to withstand complex alternating loads in existing excavator sticks.
[0010] To achieve the above objectives, the present invention provides a stick, comprising a stick body, a front support at the front end of the stick body, a rear support at the rear end of the stick body, and a connecting structure inside the stick body; the stick body includes an upper wing plate, a lower wing plate, a left web plate, and a right web plate; the connecting structure includes a central body and several peripheral stiffeners; the central body is fixedly connected to the several peripheral stiffeners; the left end face of the central body and the peripheral stiffeners is fixedly connected to the left web plate; the right end face of the central body and the peripheral stiffeners is fixedly connected to the right web plate; and the ends of the several peripheral stiffeners away from the central body are respectively fixedly connected to the upper wing plate, the lower wing plate, and the rear support.
[0011] Furthermore, the central body is a seamless tube, a rectangular channel steel, or a polygonal profile, and the outer stiffening plate is an L-shaped bent plate or an I-shaped flat plate.
[0012] Furthermore, the central body is a seamless tube extending axially in the left and right directions, and a number of peripheral stiffeners are distributed sequentially around the circumference of the central body, with one end of the peripheral stiffeners near the central body being connected and fixed to the circumferential surface of the central body.
[0013] Furthermore, the rear support protrudes from the inner side of the rear end of the lower wing plate, and the connecting structure is located above and in front of the rear support; the two L-shaped bent plates above the central body are connected and fixed to the upper wing plate, the L-shaped bent plate below the central body is connected and fixed to the lower wing plate, and the I-shaped flat plate below the central body is connected and fixed to the rear support, so that the upper and lower sides of the central body respectively form stable triangular areas.
[0014] Furthermore, the central body is in surface contact with and welded to the outer perimeter stiffening plate, the central body is in surface contact with and welded to the left web and the right web; the outer perimeter stiffening plate is in surface contact with and welded to the left web and the right web; the L-shaped bent plate is in surface contact with and welded to the upper wing plate and the lower wing plate; and the I-shaped flat plate is in surface contact with and welded to the rear support.
[0015] Furthermore, an upper ear plate is provided on the outer side of the rear end of the upper wing plate, and plug welding holes are provided on the front and rear dovetails of the upper ear plate. The two L-shaped bent plates above the central body are plug welded to the plug welding holes on both sides of the upper ear plate. A plug welding hole is provided on the lower wing plate, and an L-shaped bent plate below the central body is plug welded to the plug welding hole of the lower wing plate.
[0016] Furthermore, a lower ear plate is provided on the outer side of the lower wing plate. The lower ear plate is located in front of and below the rear support. A plug welding hole is provided on the rear dovetail of the lower ear plate. An L-shaped bent plate below the central body is plug welded to the plug welding hole on the rear side of the lower ear plate.
[0017] Furthermore, the front end of the stick body is provided with a middle support, which is located behind the front support; the rear end of the stick body is provided with a rear ear plate, which is located behind the upper wing plate and the lower wing plate.
[0018] Furthermore, a rear sealing plate is provided between the rear end of the upper wing plate and the rear end of the lower wing plate. The rear sealing plate protrudes rearward, and the upper wing plate is inclined forward and downward. The upper wing plate, the lower wing plate, the left belly plate, the right belly plate, and the rear sealing plate form a stick box-shaped structure. The rear ear plate protrudes from the outer side of the rear sealing plate.
[0019] This utility model also provides an engineering machinery, including an engineering machinery body, and a stick as described in any of the above technical solutions, wherein the stick is disposed on the engineering machinery body; the front support is hinged to the bucket, and the rear support is hinged to the boom.
[0020] In summary, the application of the technical solution of this utility model has the following beneficial effects: the structure of this utility model is reasonable, (1) by including a stick body, a front support at the front end of the stick body, a rear support at the rear end of the stick body, and a connecting structure inside the stick body; thus the connecting structure is set inside the stick body. (2) The stick body includes an upper wing plate, a lower wing plate, a left web plate, and a right web plate. The connecting structure includes a central body and several peripheral stiffeners. The central body is connected and fixed between several peripheral stiffeners. The left end face of the central body and the peripheral stiffeners is connected and fixed to the left web plate. The right end face of the central body and the peripheral stiffeners is connected and fixed to the right web plate. The ends of the peripheral stiffeners away from the central body are respectively connected and fixed to the upper wing plate, the lower wing plate, and the rear support. Therefore, compared with the prior art, this utility model innovatively proposes a connecting structure. The connecting structure is connected and fixed to the upper / lower wing plates, the left / right web plates, and the rear support of the stick. Compared with a single reinforcing plate, the fixed connection area between the connecting structure and the stick is greatly increased. Thus, the overall stiffness of the stick is greatly improved, which can effectively adapt to complex bending and torsional conditions and effectively suppress buckling deformation. Due to the role of the central body, the force transmission of the connecting structure is more uniform and smooth, avoiding uneven stress on the overall structure and solving the problem of poor ability to withstand complex alternating loads. Analysis shows that this invention significantly improves the overall stiffness and strength of the boom, greatly optimizes the force transmission path of the hinge hole of the boom rear support, and effectively transmits the force to the boom's stable neutral layer (i.e., the area where the connection structure is located), thereby making the boom more uniform and reasonable in terms of force distribution, while also improving the boom's bending and torsional resistance. Attached Figure Description
[0021] Figure 1 This is a structural diagram of existing technology;
[0022] Figure 2 This is a schematic diagram of the structure of this utility model;
[0023] Figure 3 This is a three-dimensional structural schematic diagram of the present invention;
[0024] Figure 4 This is a three-dimensional structural diagram of the connection structure of this utility model;
[0025] Figure 5 This is a top view of the structure of this utility model;
[0026] Figure 6 This is a schematic diagram of the stable triangular region of this utility model;
[0027] Explanation of reference numerals in the attached drawings: boom body (1), front support (2), rear support (3), connecting structure (4), upper ear plate (5), plug weld hole (6), lower ear plate (7), middle support (8), rear ear plate (9), stabilizing triangle area (10); upper wing plate (101), lower wing plate (102), left web plate (103), right web plate (104), rear sealing plate (105); central body (401), outer perimeter stiffener (402), L-shaped bent plate (4021), I-shaped flat plate (4022), upper ear plate front dovetail (501), upper ear plate rear dovetail (502), lower ear plate rear dovetail (701), lower ear plate front dovetail (702). Existing upper wing plate (20), existing upper ear plate front dovetail (30), existing upper ear plate (40), existing upper ear plate rear dovetail (50), existing rear ear plate (60), existing rear sealing plate (70), existing rear support (80), existing internal reinforcing rib plate (90), existing lower ear plate rear dovetail (100), existing lower ear plate (110), existing lower ear plate front dovetail (120), existing lower wing plate (130), existing belly plate (140), existing middle support (150), existing front support (160). Detailed Implementation
[0028] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present utility model, but this does not constitute a limitation on the scope of protection of the present utility model.
[0029] In this utility model, for clearer description, the following explanation is provided: The observer faces the attached... Figure 2 In this observation, the left side of the observer is designated as rear, the right side as front, the front of the observer as left, the rear of the observer as right, the top of the observer as up, and the bottom of the observer as down. It should be noted that the terms "front end," "rear end," "left side," "right side," "middle," "above," and "below" used in this document indicate the orientation or positional relationship based on the accompanying drawings. These are merely for the purpose of clearly describing the present invention and do not indicate or imply that the structure or component referred to must have a specific orientation or be constructed in a specific orientation. Therefore, they should not be construed as limitations on the present invention. Furthermore, the terms "first," "second," "third," and "fourth" are used only for the purpose of clarity or simplification of description and should not be construed as indicating or implying relative importance or quantity.
[0030] See Figures 2 to 6This embodiment provides a stick, including a stick body 1. The front end of the stick body 1 is provided with a front support 2, and the rear end of the stick body 1 is provided with a rear support 3. The stick body 1 is provided with a connecting structure 4 inside. The stick body 1 includes an upper wing plate 101, a lower wing plate 102, a left web plate 103, and a right web plate 104. The connecting structure 4 includes a central body 401 and a plurality of peripheral stiffeners 402. The central body 401 is connected and fixed between the plurality of peripheral stiffeners 402. The left end face of the central body 401 and the peripheral stiffeners 402 is connected and fixed to the left web plate 103. The right end face of the central body 401 and the peripheral stiffeners 402 is connected and fixed to the right web plate 104. The ends of the plurality of peripheral stiffeners 402 away from the central body 401 are respectively connected and fixed to the upper wing plate 101, the lower wing plate 102, and the rear support 3. Function: (1) By including the stick body, the front end of the stick body is provided with a front support, the rear end of the stick body is provided with a rear support, and the inside of the stick body is provided with a connecting structure; thereby the connecting structure is set inside the stick body. (2) The stick body includes an upper wing plate, a lower wing plate, a left web plate, and a right web plate. The connecting structure includes a central body and several peripheral stiffeners. The central body is connected and fixed between several peripheral stiffeners. The left end face of the central body and the peripheral stiffeners is connected and fixed to the left web plate. The right end face of the central body and the peripheral stiffeners is connected and fixed to the right web plate. The ends of the peripheral stiffeners away from the central body are respectively connected and fixed to the upper wing plate, the lower wing plate, and the rear support. Therefore, compared with the prior art, this utility model innovatively proposes a connecting structure. The connecting structure is connected and fixed to the upper / lower wing plates, the left / right web plates, and the rear support of the stick. Compared with a single reinforcing plate, the fixed connection area between the connecting structure and the stick is greatly increased. Thus, the overall stiffness of the stick is greatly improved, which can effectively adapt to complex bending and torsional conditions and effectively suppress buckling deformation. Due to the role of the central body, the force transmission of the connecting structure is more uniform and smooth, avoiding uneven stress on the overall structure and solving the problem of poor ability to withstand complex alternating loads. Analysis shows that this invention significantly improves the overall stiffness and strength of the boom, greatly optimizes the force transmission path of the hinge hole of the boom rear support, and effectively transmits the force to the boom's stable neutral layer (i.e., the area where the connection structure is located), thereby making the boom more uniform and reasonable in terms of force distribution, while also improving the boom's bending and torsional resistance.
[0031] Specifically, the central body 401 is a seamless tube, rectangular channel steel, or polygonal profile, and the outer stiffening plate 402 is an L-shaped bent plate 4021 or an I-shaped flat plate 4022. Function: The central body 401 has a structure of seamless tube, rectangular channel steel, or polygonal profile, etc.; the outer stiffening plate 402 has a structure of L-shaped bent plate, I-shaped flat plate, etc.
[0032] Specifically, the central body 401 is a seamless tube extending axially to the left and right, and several peripheral stiffening plates 402 are distributed sequentially around the circumference of the central body 401. The ends of the peripheral stiffening plates 402 closest to the central body 401 are connected and fixed to the circumferential surface of the central body 401. Function: The seamless tube can make the force transmission more uniform and smooth.
[0033] Specifically, the rear support 3 protrudes from the inner side of the rear end of the lower wing plate 102, and the connecting structure 4 is located above and in front of the rear support 3; two L-shaped bent plates 4021 above the central body 401 are connected and fixed to the upper wing plate 101, one L-shaped bent plate 4021 below the central body 401 is connected and fixed to the lower wing plate 102, and one I-shaped flat plate 4022 below the central body 401 is connected and fixed to the rear support 3, so that stable triangular regions 10 are formed on the upper and lower sides of the central body 401 respectively. Function: See Figure 6 The upper and lower sides of the central body 401 can form stable triangular areas, which further improves the overall rigidity and strength of the boom, and further enhances its bending and torsional resistance. The number of outer stiffeners depends on the reinforcement requirements; only four are listed in this example.
[0034] Specifically, the central body 401 is in surface contact with and welded to the outer stiffening plate 402; the central body 401 is in surface contact with and welded to the left web plate 103 and the right web plate 104; the outer stiffening plate 402 is in surface contact with and welded to the left web plate 103 and the right web plate 104; the L-shaped bent plate 4021 is in surface contact with and welded to the upper wing plate 101 and the lower wing plate 102; and the I-shaped flat plate 4022 is in surface contact with and welded to the rear support 3. Function: By connecting the structure 4 to the upper / lower wing plates, left / right web plates, and rear support of the boom, and welding them together, the force transmission is more uniform and smoother compared to a single reinforcing plate, avoiding uneven stress on the overall structure and solving the problem of poor ability to withstand complex alternating loads. In other words, in terms of structural stress, it avoids the problem of surface contact with a single reinforcing plate. This makes the force on the boom more uniform and reasonable, the force flow transmission smoother, and avoids stress concentration. In terms of structural strength and fatigue resistance: Because the stress distribution is more rational, the stress concentration problem is effectively solved, and the stress levels in both high-stress and stable stress areas are reduced. This significantly improves resistance to fatigue failure, increases fatigue life, and enhances the ability to handle complex alternating loads, thereby reducing the probability of fatigue cracking failure, lowering market failure feedback rates, and saving maintenance costs. In terms of structural stiffness: Because the fixed connection area between the combined central structure (i.e., connecting structure 4) and the boom is significantly increased, and all areas are in surface contact, a local stable triangular region is formed. Thus, the overall stiffness of the boom is greatly improved, effectively adapting to complex bending and torsional conditions while effectively suppressing buckling deformation.
[0035] Specifically, an upper ear plate 5 protrudes from the outer side of the rear end of the upper wing plate 101. The dovetails on the front and rear sides of the upper ear plate 5 are respectively provided with plug welding holes 6. Two L-shaped bent plates 4021 above the central body 401 are plug-welded to the plug welding holes 6 on both sides of the upper ear plate 5. A plug welding hole 6 is provided on the lower wing plate 102, and an L-shaped bent plate 4021 below the central body 401 is plug-welded to the plug welding hole 6 of the lower wing plate 102. Function: The dovetails on the front and rear sides of the upper ear plate 5 are the front dovetail 501 and the rear dovetail 502, which greatly optimizes the force transmission path of the hinge hole of the upper ear plate 5 on the boom, effectively transmitting the force to the stable neutral layer of the boom (i.e., the area where the connecting structure is located).
[0036] Specifically, a lower lug plate 7 protrudes from the outer side of the lower wing plate 102. The lower lug plate 7 is located below and in front of the rear support 3. A plug weld hole 6 is provided on the rear dovetail of the lower lug plate 7. An L-shaped bent plate 4021 below the central body 401 is plug welded to the plug weld hole 6 on the rear side of the lower lug plate 7. Function: The front and rear dovetails of the lower lug plate 7 are the rear dovetail 701 and the front dovetail 702; this greatly optimizes the force transmission path of the hinge hole of the lower lug plate 7, effectively transmitting it to the stable neutral layer of the stick (i.e., the area where the connection structure is located). In practice, holes can be made in the upper wing plate 101 and the lower wing plate 102 for plug weld fixing, and the fixing area is near the front dovetail 501, the rear dovetail 502, and the rear dovetail 701 of the upper lug plate. See [reference needed]. Figure 5 .
[0037] Specifically, the front end of the stick body 1 is provided with a central support 8, which is located behind the front support 2; the rear end of the stick body 1 is provided with a rear lug plate 9, which is located behind the upper wing plate 101 and the lower wing plate 102. Function: The central support 8 and the rear lug plate 9 can act as hinges when needed.
[0038] Specifically, a rear sealing plate 105 is provided between the rear end of the upper wing plate 101 and the rear end of the lower wing plate 102. The rear sealing plate 105 protrudes rearward, while the upper wing plate 101 tilts forward and downward. The upper wing plate 101, lower wing plate 102, left web plate 103, right web plate 104, and rear sealing plate 105 form a boom box-shaped structure. The rear ear plate 9 protrudes from the outer side of the rear sealing plate 105. Function: The rear sealing plate 105 allows the boom to better form a boom box-shaped structure.
[0039] This utility model also provides an engineering machinery, including a machinery body and a stick according to any of the above-mentioned technical solutions, the stick being mounted on the machinery body; the front support 2 is hinged to the bucket, and the rear support 3 is hinged to the boom. Application: The stick of this utility model can be applied to engineering machinery such as excavators and backhoe loaders.
[0040] In summary, this utility model innovatively proposes a connecting structure, which is placed inside the cavity of the boom box structure, significantly improving the overall stiffness and strength of the boom, greatly optimizing the force transmission path of the upper ear plate, rear support, and lower ear plate hinge holes of the boom, and effectively transmitting the force to the stable neutral layer of the boom (i.e., the area where the connecting structure is located), thereby making the force on the boom more uniform and reasonable, while improving the boom's bending and torsional resistance.
[0041] The above description is the preferred embodiment of this utility model. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of this utility model, and these improvements and modifications are also considered to be within the protection scope of this utility model.
Claims
1. A stick, comprising a stick body (1), characterized in that: The front end of the arm body (1) is provided with a front support (2), the rear end of the arm body (1) is provided with a rear support (3), and the inside of the arm body (1) is provided with a connecting structure (4); the arm body (1) comprises an upper wing plate (101), a lower wing plate (102), a left web plate (103) and a right web plate (104), the connecting structure (4) comprises a center body (401) and a plurality of peripheral rib plates (402), the center body (401) is connected and fixed between the plurality of peripheral rib plates (402), the left end face of the center body (401) and the peripheral rib plate (402) is connected and fixed with the left web plate (103), the right end face of the center body (401) and the peripheral rib plate (402) is connected and fixed with the right web plate (104), and one end of the plurality of peripheral rib plates (402) away from the center body (401) is connected and fixed with the upper wing plate (101), the lower wing plate (102) and the rear support (3) respectively.
2. The arm as claimed in claim 1, characterized in that: The center body (401) is a seamless pipe or a rectangular channel steel or a polygonal profile piece, and the peripheral rib plate (402) is an L-shaped bent plate (4021) or an I-shaped flat plate (4022).
3. The arm of claim 2 wherein: The center body (401) is an axially left-right extending seamless pipe, the plurality of peripheral rib plates (402) are sequentially distributed around the circumferential direction of the center body (401), and one end of the plurality of peripheral rib plates (402) close to the center body (401) is connected and fixed with the circumferential face of the center body (401).
4. The arm of claim 3 wherein: The rear support (3) is protrudingly arranged on the inner side face of the rear end of the lower wing plate (102), and the connecting structure (4) is located above the front of the rear support (3); two L-shaped bent plates (4021) above the center body (401) are connected and fixed with the upper wing plate (101), one L-shaped bent plate (4021) below the center body (401) is connected and fixed with the lower wing plate (102), and one I-shaped flat plate (4022) below the center body (401) is connected and fixed with the rear support (3), so that the upper and lower sides of the center body (401) respectively form stable triangular areas (10).
5. The arm of claim 4 wherein: The center body (401) and the peripheral rib plate (402) are in surface-to-surface contact and welded fixed, the center body (401) and the left web plate (103) and the right web plate (104) are in surface-to-surface contact and welded fixed; the peripheral rib plate (402) and the left web plate (103) and the right web plate (104) are in surface-to-surface contact and welded fixed, the L-shaped bent plate (4021) and the upper wing plate (101) and the lower wing plate (102) are in surface-to-surface contact and welded fixed, and the I-shaped flat plate (4022) and the rear support (3) are in surface-to-surface contact and welded fixed.
6. The arm of claim 5 wherein: The outer side of the rear end of the upper wing plate (101) is provided with an upper lug plate (5), the front and rear sides of the upper lug plate (5) are respectively provided with plug welding holes (6), the two L-shaped bending plates (4021) above the center body (401) are respectively plug welded with the plug welding holes (6) on the two sides of the upper lug plate (5); the lower wing plate (102) is provided with a plug welding hole (6), and one of the L-shaped bending plates (4021) below the center body (401) is plug welded with the plug welding hole (6) of the lower wing plate (102).
7. The arm of claim 6 wherein: The outer side of the rear end of the upper wing plate (101) is provided with an upper lug plate (5), the front and rear sides of the upper lug plate (5) are respectively provided with plug welding holes (6), the two L-shaped bending plates (4021) above the center body (401) are respectively plug welded with the plug welding holes (6) on the two sides of the upper lug plate (5); the lower wing plate (102) is provided with a plug welding hole (6), and one of the L-shaped bending plates (4021) below the center body (401) is plug welded with the plug welding hole (6) of the lower wing plate (102).
8. A stick according to any one of claims 1 to 7, characterized in that: The front end of the arm body (1) is further provided with a middle support (8), and the middle support (8) is located behind the front support (2); the rear end of the arm body (1) is further provided with a rear lug plate (9), and the rear lug plate (9) is located behind the upper wing plate (101) and the lower wing plate (102).
9. The arm of claim 8 wherein: The rear end of the upper wing plate (101) and the rear end of the lower wing plate (102) are provided with a rear sealing plate (105), the rear sealing plate (105) protrudes backward, the upper wing plate (101) inclines forward and downward, the upper wing plate (101), the lower wing plate (102), the left web plate (103), the right web plate (104) and the rear sealing plate (105) form an arm box structure, and the rear lug plate (9) protrudes on the outer side of the rear sealing plate (105).
10. A working machine comprising a working machine body, characterised in that: The arm is arranged on the body of the engineering machinery, the front support (2) is hinged with a bucket, and the rear support (3) is hinged with a movable arm.