Off-road vehicle recovery tool

Abstract

The application discloses a kind of off-road motor vehicle wrecking tools, including wrecking tool (such as snow shovel, snow plow etc.), frame and mounting seat, the frame is installed between the wrecking tool and mounting seat, the frame includes forearm assembly and rear arm assembly, the forearm assembly is articulated with rear arm assembly by connecting shaft, the connecting shaft is externally provided with torsional spring, the torsional spring is respectively matched with the forearm assembly and rear arm assembly, to apply elastic force to the forearm assembly and rear arm assembly, by being divided into forearm assembly and rear arm assembly to the frame, and the forearm assembly is flexibly connected by elastic connecting component with rear arm assembly to prevent the frame from being damaged by the upward pulling force of steel rope when encountering obstacles;In addition, quick disassembly and assembly are realized with mounting seat by dismounting mechanism, so that mounting seat only needs to be installed to the bottom of power equipment, and dismounting and assembly are realized by dismounting mechanism and mounting seat to make dismounting and assembly more convenient.

Description

Technical Field

[0001] This invention relates to the field of obstacle removal tools, and in particular to an obstacle removal tool for off-road vehicles. Background Technology

[0002] Snow accumulation on roads causes numerous inconveniences and disruptions to traffic, people's travel, work, and daily life, and in severe cases, it can even pose safety hazards. Currently, the main snow removal methods in my country include snow melting and snow removal, manual snow removal, and mechanical snow removal. Each method has its advantages and limitations. Snow melting and snow removal is suitable for situations with relatively light snowfall, but its effectiveness is poor when faced with large areas of snow accumulation, such as airport runways and roads. Sometimes, people also use manual snow shoveling, but manual snow removal is expensive and inefficient, affecting traffic flow and driving safety. Therefore, people are increasingly inclined to use a method of installing clearing tools (such as snow shovels and snowplows) on four-wheeled motorcycles to shovel snow while moving forward.

[0003] A search revealed a Chinese utility model patent (authorization announcement number: CN210887071U) that discloses a snow shovel. The existing snow shovel includes a frame, and the rear end of the frame is used to install it onto the chassis of a four-wheeled motorcycle. When the existing snow shovel needs to be installed onto the four-wheeled motorcycle, the entire snow shovel needs to be installed onto the chassis of the four-wheeled motorcycle at the same time. However, the existing snow shovel is large in size and weight, so the installation and disassembly process is relatively troublesome.

[0004] In addition, the existing frame is a one-piece structure. During use, the frame is subjected to the upward tension of the steel cable, which can easily cause the frame to bend and deform, affecting the working performance of the snowplow. Therefore, it is urgent to improve the above-mentioned shortcomings. Summary of the Invention

[0005] The purpose of this invention is to address the above-mentioned problems. This invention provides an off-road vehicle obstacle clearing tool, which has the advantages of quick assembly and disassembly with the power equipment and is less likely to cause bending and deformation of the vehicle frame.

[0006] To achieve the above objectives, the present invention provides the following technical solution: an off-road vehicle obstacle clearing tool, comprising an obstacle clearing tool, a frame, and a mounting base. The frame is mounted between the obstacle clearing tool and the mounting base. The frame includes a front arm assembly and a rear arm assembly, which are hinged together by a connecting shaft. A torsion spring is provided outside the connecting shaft, and the torsion spring abuts against the front arm assembly and the rear arm assembly respectively to apply an elastic force to the front arm assembly and the rear arm assembly. A disassembly and assembly mechanism is provided at the rear end of the rear arm assembly, and the mounting base is detachably mounted on the disassembly and assembly mechanism.

[0007] Preferably, the disassembly and assembly mechanism includes a connecting frame, a locking hook, and a fixing hook. The fixing hook is fixedly installed on the connecting frame, and the locking hook is rotatably engaged with the connecting frame. The fixing hook is provided with a locking groove with an opening, and a spring is provided between the connecting frame or the fixing hook and the locking hook.

[0008] Preferably, the locking hook is rotatably mounted on the connecting frame via a rotating shaft. The fixed hook is provided with a first guide surface. The locking hook has a first end and a second end located on both sides of the rotating shaft. The first end of the locking hook is provided with a second guide surface. When the locking groove is in the closed state, the first guide surface and the second guide surface form a guide groove.

[0009] Preferably, a foot pedal assembly is movably mounted on the frame, and a pull rope is provided between the foot pedal assembly and the locking hook. The movement of the foot pedal assembly drives the locking hook to move through the pull rope.

[0010] Preferably, the second end of the locking hook is provided with a mounting hole, the foot pedal assembly includes a foot pedal and a rotating shaft, the foot pedal is mounted on the rotating shaft, the rotating shaft is provided with a fixing plate, the fixing plate is provided with a through hole, and the through hole is connected to the mounting hole on the locking hook through the pull rope.

[0011] Preferably, a second fixing plate is provided on the rotating shaft, and a tension spring is connected between the second fixing plate and the vehicle frame.

[0012] Preferably, the device further includes an adjustment component, which is disposed in conjunction with the first working end of the torsion spring, and is used to adjust the preload of the torsion spring.

[0013] Preferably, the adjustment assembly includes an adjustment plate and an adjustment bolt, the adjustment bolt being threaded onto the adjustment plate, and the bottom of the adjustment bolt abutting against the forearm assembly.

[0014] Preferably, the adjusting plate is provided with a positioning slot, and the first working end of the torsion spring is correspondingly engaged with the positioning slot.

[0015] Preferably, a limiting component is provided between the forearm assembly and the rear arm assembly. The limiting component includes a first limiting plate fixed to the forearm assembly and a second limiting plate fixed to the rear arm assembly. The first limiting plate has a first protrusion that abuts against the upper surface of the rear arm assembly, and the second limiting plate has a second protrusion that abuts against the upper surface of the forearm assembly. The first limiting plate and the second limiting plate are connected by a connecting shaft.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0017] The present invention provides an off-road vehicle obstacle clearing tool, which divides the vehicle frame into a front arm assembly and a rear arm assembly, and the front arm assembly and the rear arm assembly are flexibly connected by an elastic connecting component, thereby preventing the vehicle frame from being damaged by the upward pulling force of the steel cable when encountering an obstacle.

[0018] In addition, the disassembly and assembly mechanism enables quick disassembly and assembly with the mounting base. This allows the tool to be installed simply by attaching the mounting base to the bottom of the power equipment and then using the disassembly and assembly mechanism in conjunction with the mounting base, making disassembly and assembly more convenient. Attached Figure Description

[0019] Figure 1 This is a three-dimensional structural diagram of the present invention;

[0020] Figure 2 This is a three-dimensional structural diagram of the disassembly and assembly mechanism of the present invention;

[0021] Figure 3 This is a partial three-dimensional structural diagram of the disassembly and assembly mechanism of the present invention;

[0022] Figure 4 This is a top view of the disassembly and assembly mechanism of the present invention;

[0023] Figure 5 This is a three-dimensional structural diagram of the fixing hook of the disassembly and assembly mechanism of the present invention;

[0024] Figure 6 This is a three-dimensional structural diagram of the locking hook of the disassembly and assembly mechanism of the present invention;

[0025] Figure 7 for Figure 1 A magnified structural diagram of A in the middle;

[0026] Figure 8 This is a three-dimensional structural diagram of the adjustment plate of the present invention.

[0027] Figure Descriptions: 1. Clearing tool; 2. Frame; 21. Front boom assembly; 211. Front boom support; 212. First connecting plate; 22. Rear boom assembly; 221. Rear boom support; 222. Second connecting plate; 3. Mounting base; 41. Connecting shaft; 42. Torsion spring; 43. Adjusting plate; 44. Adjusting bolt; 45. Fixing nut; 46. Locking nut; 47. Vertical plate; 48. Positioning slot; 5. Disassembly / assembly mechanism; 51. Connecting frame; 52. Fixing hook; 520. Arc-shaped surface; 521. Locking groove; 522. First guide surface; 523. First connecting groove; 53. Locking hook; 530. Pressing groove; 5300 531. Arc-shaped groove; 532. Second guide surface; 533. Pressing part; 534. Mounting hole; 535. Protrusion; 536. Second connecting groove; 54. Spring; 55. Rotating shaft; 56. Pad; 57. Mounting groove; 58. Connecting plate; 591. First connecting piece; 592. Second connecting piece; 6. Foot pedal assembly; 61. Pull rope; 62. Foot pedal; 63. Rotating shaft; 64. First fixing plate; 641. First through hole; 65. Second fixing plate; 651. Second through hole; 66. Tension spring; 71. First limiting plate; 711. First protrusion; 72. Second limiting plate; 721. Second protrusion. Detailed Implementation

[0028] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] like Figures 1-8 As shown, an off-road vehicle obstacle clearing tool includes an obstacle clearing tool 1, a frame 2, and a mounting base 3. In this application, the obstacle clearing tool 1 can be replaced by a snow shovel, snowplow, or other tools used for obstacle clearing. The frame 2 is installed between the obstacle clearing tool 1 and the mounting base 3. The frame 2 includes a front arm assembly 21, a rear arm assembly 22, and an elastic connecting component. The front arm assembly 21 and the rear arm assembly 22 are flexibly connected by the elastic connecting component. The rear end of the rear arm assembly 22 is provided with a disassembly and assembly mechanism 5. The mounting base 3 is detachably installed on the disassembly and assembly mechanism 5. The mounting base 3 is installed at the bottom of the power equipment. The bottom of the mounting base 3 is provided with a locking rod that can be detachably engaged with the disassembly and assembly mechanism 5. The power equipment can be a motor vehicle or an off-road vehicle, or other power equipment that can be replaced.

[0030] The disassembly and assembly mechanism 5 includes a connecting frame 51, a locking hook 53, and a fixing hook 52. The fixing hook 52 is fixedly installed on the connecting frame 51, and the locking hook 53 is rotatably engaged with the connecting frame 51. The fixing hook 52 is provided with a locking groove 521 with an opening. The locking groove 521 can switch between open and closed states by the rotation of the locking hook 53. A spring 54 is provided between the fixing hook 52 and the locking hook 53. The spring 54 always tends to make the locking groove 521 close.

[0031] The locking hook 53 is rotatably mounted on the connecting frame 51 via the rotating shaft 55. The fixed hook 52 is provided with a first guide surface 522. The locking hook 53 has a first end and a second end located on both sides of the rotating shaft 55. The first end of the locking hook 53 is provided with a second guide surface 531. When the locking groove 521 is in the closed state, the first guide surface 522 and the second guide surface 531 form a guide groove. In this embodiment, the guide groove is "V" shaped.

[0032] The fixed hook 52 is provided with an arc-shaped surface 520, and the locking hook 53 is provided with an arc-shaped groove 5300. The arc-shaped surface 520 and the arc-shaped groove 5300 are fitted together. When the locking hook 53 rotates around the axis of the rotating shaft 55, the arc-shaped surface 520 and the arc-shaped groove 5300 always remain fitted together. Therefore, the arc-shaped surface 520 and the arc-shaped groove 5300 cooperate to play a guiding role.

[0033] The connecting frame 51 is provided with an installation groove 57. The fixing hook 52 and the locking hook 53 are both set in the installation groove 57. The fixing hook 52 is provided with a pad 56. The sum of the thickness of the pad 56 and the fixing hook 52 is greater than the thickness of the locking hook 53, so that there is a gap between the locking hook 53 and the installation groove 57, thereby making the locking hook 53 rotate more smoothly.

[0034] The second end of the locking hook 53 is provided with a protruding pressing part 532. By manually pressing the pressing part 532, the locking hook 53 is driven to swing, thereby switching the locking groove 521 from the closed state to the open state, i.e., the unlocking function. The second end of the locking hook 53 is provided with a pressing groove 530, and the pressing groove 530 is provided with several protrusions 534. The protrusions 534 increase the friction force, thereby preventing the finger from slipping between the finger and the locking hook 53 when manually pressing.

[0035] The second end of the locking hook 53 is provided with a mounting hole 533 for installing a pull rope 61. By connecting a pull rope 61 inside and outside the mounting hole 533, the unlocking function can be achieved by pulling the pull rope 61.

[0036] The fixing hook 52 is provided with a first connecting groove 523, the locking hook 53 is provided with a second connecting groove 535, and the spring 54 is installed in the first connecting groove 523 and the second connecting groove 535.

[0037] The connecting frame 51 includes two connecting plates 58, a plurality of first connecting members 591 and a plurality of second connecting members 592. The first connecting members 591 are used to install the connecting plates 58 onto other equipment that requires the installation of locking devices. The second connecting members 592 are used to fix the fixing hooks 52 onto the connecting plates 58. The mounting groove 57 is formed between the two connecting plates 58. It should be noted that the first connecting members 591 and the second connecting members 592 are both bolts and nuts.

[0038] A foot pedal assembly 6 is movably mounted on the frame 2. A pull rope 61 is provided between the foot pedal assembly 6 and the locking hook 53. The movement of the foot pedal assembly 6 drives the locking hook 53 to move through the pull rope 61.

[0039] The second end of the locking hook 53 is provided with a mounting hole 533. The foot pedal assembly 6 includes two foot pedals 62 and a rotating shaft 63. The foot pedals 62 are symmetrically arranged at both ends of the rotating shaft 63. The rotating shaft 63 is rotatably engaged with the frame 2. The rotating shaft 63 is provided with two first fixing plates 64. Each of the first fixing plates 64 is provided with a first through hole 641. The corresponding first through hole 641 is connected to the mounting hole 533 by the pull rope 61.

[0040] The foot pedal 62 can swing back and forth between a first position and a second position. When the foot pedal 62 is in the first position, the locking groove 521 is in a closed state. When the foot pedal 62 is in the second position, the locking groove 521 is in an open state.

[0041] In a further optimization, a second fixing plate 65 is provided on the rotating shaft 63, and a tension spring 66 is connected between the second fixing plate 65 and the frame 2. The tension spring 66 always has the tendency to drive the foot pedal 62 to swing towards the first position.

[0042] The second fixing plate 65 is provided with a second through hole 651, and one end of the tension spring 66 is installed in the second through hole 651.

[0043] When mounting seat 3 needs to be installed onto frame 2: by aligning the locking rod on mounting seat 3 with the guide slots on the two disassembly / assembly structures, pressing down on mounting seat 3 causes the locking rod to move downwards, thereby contacting the first and second inclined surfaces. As the locking rod continues to move, it pushes the locking hook 53 to rotate around the axis of the pivot 55. The locking rod pushes the locking hook 53 to overcome the elastic force of spring 54 and rotate around the axis of pivot 55, thereby switching the locking groove 521 from a closed state to an open state, allowing the locking rod to enter the locking groove 521. When the locking rod is fully inside the locking groove 521, spring 54 pushes the locking hook 53 to reset, thereby switching the locking groove 521 from an open state to a closed state, thus achieving the function of locking mounting seat 3.

[0044] When the mounting base 3 needs to be removed: stepping on the foot pedal 62 causes the rotating shaft 63 to rotate, which in turn causes the first fixing plate 64 to swing, which in turn pulls the pull rope 61, causing the locking hook 53 to swing around the axis of the rotating shaft 55, thereby switching the locking groove 521 from the closed state to the open state, so that the locking rod can be removed from the locking groove 521, thus achieving the function of removing the mounting base 3. After removing the mounting base 3, releasing the foot pedal 62 causes the tension spring 66 to swing the second fixing plate 65, which in turn causes the foot pedal 62 to move from the second position to the first position, which in turn causes the locking hook 53 to swing in the opposite direction around the axis of the rotating shaft 55, thereby switching the locking groove 521 from the open state to the closed state, thus achieving the function of resetting the locking hook 53 and the foot pedal 62.

[0045] The elastic connection assembly includes a connecting shaft 41 and a torsion spring 42. The forearm assembly 21 and the rear arm assembly 22 are hinged through the connecting shaft 41. The torsion spring 42 is sleeved on the outer periphery of the connecting shaft 41. The torsion spring 42 has a first working end that abuts against the forearm assembly 21 and a second working end that abuts against the rear arm assembly 22.

[0046] In a further optimized configuration, the forearm assembly 21 includes a forearm frame 211 and a first connecting plate 212, the rear arm assembly 22 includes a rear arm frame 221 and a second connecting plate 222, the first working end of the torsion spring 42 abuts against the first connecting plate 212, and the second end of the torsion spring 42 abuts against the second connecting plate 222.

[0047] The elastic connection assembly further includes an adjustment assembly, which is disposed at the first working end of the torsion spring 42. The adjustment assembly is used to adjust the preload of the torsion spring 42. The adjustment assembly includes an adjustment plate 43 and an adjustment bolt 44. The adjustment bolt 44 is threaded onto the adjustment plate 43, and the bottom of the adjustment bolt 44 abuts against the first connecting plate 212. By rotating the adjustment bolt 44, the adjustment plate 43 is driven to reciprocate along the axial direction of the adjustment bolt 44.

[0048] A fixing nut 45 that is threadedly engaged with the adjusting bolt 44 is fixedly installed on the adjusting plate 43. The fixing nut 45 and the adjusting plate 43 are welded together. A locking nut 46 is threadedly engaged on the outer circumference of the adjusting bolt 44.

[0049] The adjusting plate 43 is provided with a vertical plate 47, and the vertical plate 47 is provided with a positioning groove 48. The first working end of the torsion spring 42 is engaged in the positioning groove 48, thereby preventing relative movement between the torsion spring 42 and the adjusting plate 43.

[0050] In this application, the adjusting plate 43 is provided with a positioning slot 48, and both ends of the adjusting plate 43 are provided with upright plates 47. The two upright plates 47 are integrally bent with the adjusting plate 43. The positioning slot 48 is provided through each upright plate 47. In this application, the first working end of the torsion spring 42 is trapezoidal. The distance between the end of the first working end of the torsion spring 42 away from the connecting shaft 41 is smaller than the distance between the end closer to the connecting shaft 41. The first working end of the torsion spring 42 and the positioning slot 48 are engaged, thereby preventing relative movement between the adjusting plate 43 and the torsion spring 42.

[0051] Furthermore, a limiting component is provided between the forearm assembly 21 and the rear arm assembly 22 to limit the maximum rotation angle of the forearm assembly 21 and the rear arm assembly 22. This limiting component can limit the forearm assembly 21 to rotate a maximum of 25° around the connecting shaft 41, and in addition to 25°, it can be customized according to customer needs, such as 20° or 30°, or any other angle. The limiting component includes a first limiting plate 71 and a second limiting plate 72, with the first limiting plate 71 fixedly installed on the forearm assembly 21. On the boom 211, the second limiting plate 72 is fixedly installed on the rear boom 221. The first limiting plate 71 has a first protrusion 711, which is in a limiting engagement with the upper surface of the rear boom 221. The second limiting plate 72 has a second protrusion 721, which is in a limiting engagement with the upper surface of the forearm 211. When the obstacle clearing tool 1 encounters an obstacle, the forearm assembly 21 is raised so that the first protrusion 711 contacts the upper surface of the rear boom 221, limiting the maximum torsion angle.

[0052] The first limiting plate 71 and the second limiting plate 72 are provided with connecting holes for the connecting shaft 41 to pass through.

[0053] In specific operation: When the obstacle clearing tool 1 encounters an obstacle while working (such as shoveling snow, shoveling garbage, etc.), the obstacle clearing tool 1 will be lifted by the obstacle. At this time, the obstacle clearing tool 1 will drive the front boom 211 to swing upward, thereby causing the torsion spring 42 to twist. After passing the obstacle, the torsion spring 42 will return to its original position, thereby driving the obstacle clearing tool 1 and the front boom 211 to return to their original positions.

[0054] During installation: The torsion spring 42 is sleeved around the outer circumference of the connecting shaft 41, and the connecting shaft 41 is inserted into the connecting hole. The second working end of the torsion spring 42 abuts against the second connecting plate 222. The first end of the torsion spring 42 is engaged in the slot of the adjusting plate 43, so that the lower end of the adjusting plate 43 abuts against the upper surface of the first connecting plate 212. The adjusting bolt 44 is installed into the fixing nut 45, and the bottom of the adjusting bolt 44 abuts against the first connecting plate 212. By rotating the adjusting bolt 44, the adjusting plate 43 moves upward along the axial direction of the adjusting bolt 44, thereby lifting the first working end of the torsion spring 42, thus achieving a pre-tightening effect. When the pre-tightening reaches the appropriate position, the locking nut 46 is rotated, causing the locking nut 46 to move downward, thereby contacting the fixing nut 45, thus preventing the adjusting bolt 44 from loosening.

[0055] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0056] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. An off-road vehicle recovery tool comprising a recovery tool (1), a frame (2) and a mounting bracket (3), the frame (2) being mounted between the recovery tool (1) and the mounting bracket (3), characterised in that: The frame (2) comprises a front arm assembly (21) and a rear arm assembly (22), the front arm assembly (21) and the rear arm assembly (22) are hinged through a connecting shaft (41), the connecting shaft (41) is externally provided with a torsional spring (42), the torsional spring (42) is respectively matched with the front arm assembly (21) and the rear arm assembly (22) to apply an elastic force to the front arm assembly (21) and the rear arm assembly (22), the rear end of the rear arm assembly (22) is provided with a dismounting mechanism (5), the mounting seat (3) is detachably mounted on the dismounting mechanism (5), the dismounting mechanism (5) comprises a connecting frame (51), a lock hook (53) and a fixing hook (52), the fixing hook (52) is fixedly installed on the connecting frame (51), the lock hook (53) is rotationally matched on the connecting frame (51), the fixing hook (52) is provided with a lock slot (521) with an opening, a spring (54) is abutted between the connecting frame (51) or the fixing hook (52) and the lock hook (53), the lock hook (53) is rotationally installed on the connecting frame (51) through a rotating shaft (55), the fixing hook (52) is provided with a first guide surface (522), the lock hook (53) has a first end and a second end located on both sides of the rotating shaft (55), the first end of the lock hook (53) is provided with a second guide surface (531), when the lock slot (521) is in a closed state, the first guide surface (522) and the second guide surface (531) form a guide groove.

2. An off-road vehicle recovery tool as claimed in claim 1, wherein: The frame (2) is movably provided with a pedal assembly (6), a pull rope (61) is arranged between the pedal assembly (6) and the lock hook (53), and the pedal assembly (6) drives the lock hook (53) to act through the pull rope (61).

3. An off-road vehicle recovery tool as claimed in claim 2, wherein: The second end of the lock hook (53) is provided with a mounting hole (533), the pedal assembly (6) comprises a pedal (62) and a rotating shaft (63), the pedal (62) is installed on the rotating shaft (63), the rotating shaft (63) is provided with a fixing plate, the fixing plate is provided with a through hole, and the through hole is connected with the mounting hole (533) of the lock hook (53) through the pull rope (61).

4. An off-road vehicle recovery tool as claimed in claim 3, wherein: The rotating shaft (63) is provided with a second fixing plate (65), and a pull spring (66) is connected between the second fixing plate (65) and the frame (2).

5. An off-road vehicle recovery tool as claimed in claim 1, wherein: Further comprising an adjusting assembly, the adjusting assembly is matched and arranged at the first acting end of the torsional spring (42), and the adjusting assembly is used for adjusting the pre-tightening force of the torsional spring (42).

6. An off-road vehicle recovery tool as claimed in claim 5, wherein: The adjusting assembly comprises an adjusting plate (43) and an adjusting bolt (44), the adjusting bolt (44) is threadedly matched on the adjusting plate (43), and the bottom of the adjusting bolt (44) is abutted with the front arm assembly (21).

7. An off-road vehicle recovery tool as claimed in claim 6, wherein: The adjusting plate (43) is provided with a positioning clamping groove (48), and the first acting end of the torsional spring (42) is correspondingly matched with the positioning clamping groove (48).

8. An off-road vehicle recovery tool as claimed in claim 1 or claim 5, wherein: The front arm assembly (21) and the rear arm assembly (22) are provided with a limiting assembly, the limiting assembly comprises a first limiting plate (71) fixed to the front arm assembly (21) and a second limiting plate (72) fixed to the rear arm assembly (22), the first limiting plate (71) is provided with a first protruding part (711) abutting against the upper surface of the rear arm assembly (22), the second limiting plate (72) is provided with a second protruding part (721) abutting against the upper surface of the front arm assembly (21), and the first limiting plate (71) and the second limiting plate (72) are connected through a connecting shaft (41).

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