Flexible loading and unloading device for a washing machine counterweight

Abstract

The present application provides a kind of laundry machine counterweight flexible loading and unloading device, it is related to laundry machine counterweight production technical field, including belt conveyor and linear guide, the top of linear guide is provided with base, the top of base is provided with the mechanical arm assembly for realizing the multi-axis movement of loading and unloading device, the end of mechanical arm assembly away from base is provided with flexible gripping assembly for clamping counterweight, one end of base is installed with 3D vision sensor for identifying the position of counterweight;The counterweight is clamped and fixed by the gripper assembly controlled separately, so that the flexible knuckle can be attached to the different positions of the surface of different special-shaped counterweight, the particle medium is solidified by vacuumizing, so that the silicone sleeve forms rigid gripping surface that is completely attached to the surface of counterweight, realizes lossless gripping, avoids the damage to the surface of counterweight caused by the clamping of traditional mechanical structure, effectively solves the flexible gripping demand of traditional mechanical structure that cannot adapt to different special-shaped counterweight.

Description

Technical Field

[0001] This invention relates to the field of washing machine counterweight production technology, and in particular to a flexible loading and unloading device for washing machine counterweights. Background Technology

[0002] Washing machines generate strong vibrations during high-speed spin-drying, affecting the user experience and potentially damaging the machine. Counterweights, a key structural component of washing machines, are typically made of high-density cement or metal and installed at the bottom or back of the machine. They balance the centrifugal force during high-speed drum rotation, reducing vibration and noise, and ensuring stable machine operation. Especially in drum washing machines, the importance of counterweights becomes even more pronounced as the rotation speed increases and centrifugal force grows. They effectively reduce swaying and displacement, prevent excessive noise, and extend the lifespan of the motor and vibration damping system. As a crucial component in the washing machine manufacturing process, counterweights are produced through casting or pouring processes. The need for automation and intelligentization in their loading and unloading processes is increasingly urgent. Flexible loading and unloading devices can meet the rapid and accurate loading and unloading requirements of counterweights for different washing machine models, improving the flexibility and adaptability of the production line.

[0003] However, traditional flexible loading and unloading devices require the mechanical cooperation of positioning pins and mounting holes, and their gripping structure needs to be consistent with the shape of the counterweight. This makes them unsuitable for flexible gripping of irregularly shaped or worn counterweights. In addition, the surface of the counterweight is usually uneven, and existing loading and unloading devices cannot adaptively adjust to the specific shape of the counterweight surface. This unevenness may cause gripping slippage. Summary of the Invention

[0004] The problem that this invention aims to solve is that the gripping mechanical structure of traditional loading and unloading devices cannot adapt to the flexible gripping requirements of irregularly shaped or worn counterweights, and may also cause gripping slippage due to the unevenness of the counterweight surface.

[0005] To solve the above-mentioned technical problems, the present invention provides a flexible loading and unloading device for a washing machine counterweight, including a belt conveyor and a linear guide rail installed at one end of the belt conveyor. A base is provided at the top of the linear guide rail, and a robotic arm assembly for realizing multi-axis movement of the loading and unloading device is provided at the top of the base. A flexible gripping component for clamping the counterweight is provided at the end of the robotic arm assembly away from the base, and a 3D vision sensor for identifying the position of the counterweight is installed at one end of the base. The flexible gripping component includes a connector that is connected to the robotic arm component. The bottom end of the connector is provided with two support frames. Several triangular plates are fixedly connected to the middle of the support frames. A gripper component is rotatably connected between each pair of adjacent triangular plates. The gripper assembly includes a flexible knuckle, a filling cavity is provided on one side of the inner cavity of the flexible knuckle, a piezoresistive sensor array is provided on one side of the inner wall of the flexible knuckle, a silicone sleeve is provided on the other side of the inner wall of the flexible knuckle, and the inner cavity of the filling cavity is filled with particulate medium.

[0006] Preferably, one end of the support frame is fixedly connected to a plurality of first mounting blocks, and a gripping cylinder is mounted on the first mounting block. The output end of each gripping cylinder corresponds to a gripper assembly. A first rotating rod is rotatably connected to the middle of the first mounting block and is rotatably connected to the gripping cylinder through the first rotating rod.

[0007] Preferably, a second mounting block is fixedly connected to the upper part of the outer surface of the flexible finger joint, a second rotating rod is rotatably connected to the middle part of the second mounting block, and the extended end of the gripping cylinder is fixedly connected to the middle part of the second rotating rod.

[0008] Preferably, a limiting ring is fixedly connected to the middle of the outer surface of the flexible joint, and a vacuum pipe is fixedly connected to the lower part of the outer surface of the flexible joint. One end of the vacuum pipe is connected to the filling cavity, and the other end of the vacuum pipe is connected to the input end of an external vacuum device.

[0009] Preferably, the robotic arm assembly includes a connecting shaft located at the top of the base, a rear upper arm rotatably connected to the top of the connecting shaft, a front upper arm rotatably connected to the end of the rear upper arm away from the connecting shaft, a telescopic arm provided at the end of the front upper arm away from the rear upper arm, a connecting frame fixedly connected to the extended end of the telescopic arm, and a connecting wrist rotatably connected to the inner cavity of the connecting frame.

[0010] Preferably, the top end of the connector is rotatably connected to the connector arm, and the inner cavity of the connector frame is provided with a drive motor for driving the connector to rotate. The output end of the drive motor passes through the connector frame and is fixedly connected to the top end of the connector.

[0011] Preferably, a drive motor for driving the connecting shaft to rotate is provided in the middle of the inner cavity of the base, a drive motor is provided at the connection between the connecting shaft and the rear arm, a drive motor is provided at the connection between the rear arm and the front arm, and a drive cylinder for driving the telescopic arm to extend and retract is provided at the end of the front arm away from the telescopic arm.

[0012] The technical effects and advantages of this invention are as follows: 1. This invention uses a flexible gripping component to grip irregularly shaped counterweights. The flexible gripping component consists of several gripper components, each with its own gripping cylinder control. By adjusting the air pressure, the bending angle of the flexible knuckles can be continuously controlled to adapt to surfaces with different curvatures. This allows the flexible knuckles to conform to the uneven surfaces of different irregularly shaped counterweights, enabling the loading and unloading device to meet the flexible gripping requirements of irregularly shaped or worn counterweights. At the same time, a piezoresistive sensor array integrated on the surface of the flexible knuckles monitors the distribution of gripping force in real time, preventing overload damage to the counterweights or insufficient gripping.

[0013] 2. This invention achieves non-destructive gripping by using a silicone sleeve and granular media. Several flexible knuckles are wrapped around the surface of the counterweight by the silicone sleeve. Then, a vacuum operation is performed on the inner cavity of the filling chamber through the vacuum tube, causing the granular media to solidify. Under the action of pressure difference, the silicone sleeve contracts inward, squeezing the granular media, reducing the gaps between the particles, and increasing the friction force sharply, forming a mechanical interlocking structure and a rigid gripping surface that is completely in contact with the surface of the counterweight. The microporous structure on the surface of the silicone sleeve generates an adsorption force under vacuum, which helps to fix the position of the granular media and prevents slippage. This avoids the damage to the surface of the counterweight caused by the clamping of traditional mechanical structures, effectively solving the problem that the mechanical structure of traditional loading and unloading devices cannot adapt to the flexible gripping requirements of different irregularly shaped counterweights, and there is no need to change the gripping structure according to the specific specifications and dimensions of different counterweights.

[0014] 3. This invention uses a 3D vision sensor to identify the specific location of the counterweight. After the counterweight is identified, a signal is sent to the robotic arm assembly and the flexible gripping assembly to grasp and move the counterweight. When the air extraction pipe is connected to an external vacuuming device, the connecting pipe of the external vacuuming device first passes through the inner cavity of the limiting ring before connecting to the air extraction pipe. The position of the pipe is restricted by the limiting ring to prevent the flexible knuckle from moving or rotating during use, which could cause the pipe to become entangled and affect the gripping operation of the flexible knuckle. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the overall structure of the present invention.

[0016] Figure 2 This is a schematic diagram of the flexible gripping component structure of the present invention.

[0017] Figure 3 This is a schematic diagram of the gripper assembly structure of the present invention.

[0018] Figure 4 For the present invention Figure 3 Enlarged schematic diagram of the structure at point A in the middle.

[0019] Figure 5 For the present invention Figure 3 Enlarged schematic diagram of the structure at point B.

[0020] Figure 6 This is a schematic diagram of the robotic arm assembly structure of the present invention.

[0021] The attached figures are labeled as follows: 1. Belt conveyor; 2. Linear guide rail; 3. Base; 4. Robotic arm assembly; 41. Connecting shaft; 42. Rear boom; 43. Front boom; 44. Telescopic arm; 45. Connecting frame; 46. Connecting wrist; 5. Flexible gripping assembly; 51. Connector; 52. Support frame; 53. Triangular plate; 54. Gripper assembly; 541. Flexible knuckle; 542. Filling cavity; 543. Piezoresistive sensor array; 544. Silicone sleeve; 545. Particulate medium; 546. Second mounting block; 547. Second rotating rod; 548. Limiting ring; 549. Air extraction pipe; 55. First mounting block; 56. Gripping cylinder; 57. First rotating rod; 6. 3D vision sensor. Detailed Implementation

[0022] This invention provides a flexible loading and unloading device for a washing machine counterweight, such as... Figure 1 - Figure 6 As shown, the device includes a belt conveyor 1 and a linear guide rail 2 installed at one end of the belt conveyor 1. A base 3 is provided at the top of the linear guide rail 2. A robotic arm assembly 4 for multi-axis movement of the loading and unloading device is provided at the top of the base 3. A flexible gripping component 5 for gripping a counterweight is provided at the end of the robotic arm assembly 4 away from the base 3. A 3D vision sensor 6 for identifying the position of the counterweight is installed at one end of the base 3. The formed counterweight is placed on the belt conveyor 1 for conveying. When the counterweight moves on the belt conveyor 1, the 3D vision sensor 6 identifies the specific position of the counterweight. After the counterweight is identified, a signal is sent to the robotic arm assembly 4 and the flexible gripping component 5. The flexible gripping component 5 then grips and moves the counterweight.

[0023] Furthermore, such as Figure 1 and Figure 2 As shown, the flexible gripping component 5 includes a connector 51 connected to the robotic arm component 4. Two support frames 52 are provided at the bottom of the connector 51. Several triangular plates 53 are fixedly connected to the middle of the support frames 52. A gripper component 54 is rotatably connected between each pair of adjacent triangular plates 53. The several gripper components 54 are arranged in two rows through the two support frames 52, and the several gripper components 54 are combined together through the connector 51 and the two support frames 52 to ensure the accuracy of the installation position between the several gripper components 54. At the same time, the mutual rotation between the two rows of gripper components 54 forms a clamping structure to grip the counterweight. Each gripper component 54 is controlled individually, so that the device can fit the uneven surface of the counterweight.

[0024] Furthermore, such as Figure 2 and Figure 3As shown, the gripper assembly 54 includes a flexible joint 541. A filling cavity 542 is provided on one side of the inner cavity of the flexible joint 541. A piezoresistive sensor array 543 is provided on one side of the inner wall of the flexible joint 541, and a silicone sleeve 544 is provided on the other side of the inner wall of the flexible joint 541. The inner cavity of the filling cavity 542 is filled with particulate medium 545. The piezoresistive sensor array 543 is prior art and will not be described in detail here. The piezoresistive sensor array 543 is typically composed of multiple piezoresistive sensor units arranged in a certain pattern. This allows for the detection of multi-point pressure or force distribution. When external pressure is applied to the array surface, the piezoresistive units at different locations will experience different levels of pressure, resulting in different resistance changes. The piezoresistive sensor array 543 integrated on the surface of the flexible knuckle 541 monitors the distribution of the gripping force in real time, preventing overload damage to the counterweight or insufficient gripping. At the same time, through the cooperation of the silicone sleeve 544 and the particulate medium 545, the inner wall of the flexible knuckle 541 can conform to the surface of the counterweight, achieving adaptive gripping of the surface of the non-standard counterweight.

[0025] Furthermore, such as Figure 2 and Figure 5 As shown, a number of first mounting blocks 55 are fixedly connected to one end of the support frame 52. A gripping cylinder 56 is mounted on the first mounting block 55. The output end of each gripping cylinder 56 corresponds to a gripper assembly 54. A first rotating rod 57 is rotatably connected to the middle of the first mounting block 55 and is rotatably connected to the gripping cylinder 56 through the first rotating rod 57. When gripping, the gripping cylinder 56 is activated, and the rotation of the flexible finger joint 541 is controlled by the extension and retraction of the extended end of the gripping cylinder 56.

[0026] Furthermore, such as Figure 3 , Figure 4 and Figure 5As shown, a second mounting block 546 is fixedly connected to the upper part of the outer surface of the flexible knuckle 541. A second rotating rod 547 is rotatably connected to the middle part of the second mounting block 546. The extended end of the gripping cylinder 56 is fixedly connected to the middle part of the second rotating rod 547. By extending and retracting the extended end of the gripping cylinder 56, the second rotating rod 547 and the second mounting block 546 are pushed, causing the flexible knuckle 541 to rotate between the two triangular plates 53. The first rotating rod 57 and the second rotating rod 547 rotate within the first mounting block 55 and the second mounting block 546 according to the specific extension and retraction length of their extended ends. The flexible finger joint 541 is rotated. Since each flexible finger joint 541 is controlled by a separate gripping cylinder 56, the bending angle of the flexible finger joint 541 is continuously controlled by air pressure adjustment, adapting to different curvature surfaces. This allows the flexible finger joint 541 to fit different positions on the surface of different irregularly shaped counterweights. At the same time, the silicone sleeve 544 on its inner wall wraps around the surface of the counterweight, effectively solving the problem that the mechanical structure of traditional loading and unloading devices cannot adapt to the flexible gripping requirements of different irregularly shaped counterweights. It also eliminates the need to change the gripping structure according to the specific specifications and dimensions of different counterweights.

[0027] Furthermore, such as Figure 3 and Figure 4 As shown, a limiting ring 548 is fixedly connected to the middle of the outer surface of the flexible finger joint 541, and a vacuum pipe 549 is fixedly connected to the lower part of the outer surface of the flexible finger joint 541. One end of the vacuum pipe 549 is connected to the filling cavity 542, and the other end of the vacuum pipe 549 is connected to the input end of an external vacuum device (such as a vacuum pump). When the vacuum pipe 549 is connected to the external vacuum device, the connecting pipe of the external vacuum device first passes through the inner cavity of the limiting ring 548 before connecting to the vacuum pipe 549. The limiting ring 548 restricts the position of the pipe to prevent the flexible finger joint 541 from moving or rotating during use, which could cause the pipe to become entangled and affect the gripping operation of the flexible finger joint 541. At the same time, when... After a flexible knuckle 541 is placed on the surface of the irregularly shaped counterweight, the external vacuum equipment is activated. The vacuum tube 549 is used to evacuate the inner cavity of the filling chamber 542. The vacuuming causes the particulate medium 545 to solidify. Under the pressure difference, the silicone sleeve 544 contracts inward, squeezing the particulate medium 545, reducing the gaps between the particles, and increasing the friction force sharply. This forms a mechanical interlocking structure and a rigid gripping surface that is completely in contact with the counterweight surface. The microporous structure on the surface of the silicone sleeve 544 generates an adsorption force under vacuum, which helps to fix the position of the particulate medium 545 and prevents slippage. The silicone sleeve 544 achieves non-destructive gripping, avoiding damage to the surface of the counterweight caused by the clamping of traditional mechanical structures.

[0028] Furthermore, such as Figure 1 and Figure 6As shown, the robotic arm assembly 4 includes a connecting shaft 41 located at the top of the base 3. A rear upper arm 42 is rotatably connected to the top of the connecting shaft 41. A front upper arm 43 is rotatably connected to the end of the rear upper arm 42 away from the connecting shaft 41. A telescopic arm 44 is provided at the end of the front upper arm 43 away from the rear upper arm 42. A connecting frame 45 is fixedly connected to the extended end of the telescopic arm 44. A connecting wrist 46 is rotatably connected to the inner cavity of the connecting frame 45. The main structure of the robotic arm assembly 4 is composed of the rear upper arm 42, the front upper arm 43, and the telescopic arm 44. The robotic arm assembly 4 is existing technology and will not be described in detail here (for specific structure, please refer to the existing industrial robot FANUC M-710IC / 70).

[0029] Furthermore, such as Figure 6 As shown, the top end of the connector 51 is rotatably connected to the connecting wrist 46. The inner cavity of the connecting frame 45 is provided with a drive motor for driving the connector 51 to rotate. The output end of the drive motor passes through the connecting frame 45 and is fixedly connected to the top end of the connector 51. After the flexible gripping component 5 grips the counterweight, it drives the connector 51 to rotate through the output end of the drive motor, thereby adjusting the angle of the counterweight.

[0030] Furthermore, such as Figure 6 As shown, a drive motor for driving the connecting shaft 41 to rotate is provided in the middle of the inner cavity of the base 3. A drive motor is provided at the connection between the connecting shaft 41 and the rear arm 42. A drive motor is provided at the connection between the rear arm 42 and the front arm 43. A drive cylinder for driving the telescopic arm 44 to extend and retract is provided at the end of the front arm 43 away from the telescopic arm 44. By controlling the rotation of the connection between each structure through the drive motor, the multi-axis movement of the robotic arm assembly 4 is realized. Through the coordinated rotation of multiple joints, the robotic arm assembly 4 can complete tasks such as precise positioning, grasping, and transportation in three-dimensional space. At the same time, by controlling the extension and retraction of the telescopic arm 44 through the drive cylinder, the device can grasp the counterweight more accurately and complete the loading and unloading operations.

[0031] Furthermore, such as Figure 1 As shown, one end of the belt conveyor 1 is equipped with a drive motor for its rotation, and one end of the linear guide rail 2 is equipped with a drive device for driving the base 3 to move linearly. The drive device includes a servo motor, a lead screw, a slider, etc. The linear guide rail 2 and the drive device are existing technologies and will not be described in detail here. The servo motor controls the lead screw to rotate, which drives the slider to move linearly within the linear guide rail 2, thereby driving the drive base 3 to move on the side of the belt conveyor 1 to ensure the accuracy of the counterweight gripping position.

[0032] The working principle of this invention is as follows: First, the formed counterweight is placed on a belt conveyor 1 for transport. As the counterweight moves on the belt conveyor 1, the specific position of the counterweight is identified by a 3D vision sensor 6. After the counterweight is identified, a signal is sent to the robotic arm assembly 4 and the flexible gripping assembly 5. Upon receiving the signal, the electrical equipment of each component in the robotic arm assembly 4 is activated. The drive motors corresponding to each component control the rotation of the connections between each structure, realizing the multi-axis movement of the robotic arm assembly 4. Through the coordinated rotation of multiple joints, the robotic arm assembly 4 can perform precise positioning, gripping, and transportation in three-dimensional space. The task involves simultaneously controlling the extension and retraction of the telescopic arm 44 via a drive cylinder. Based on data collected by the 3D vision sensor 6, the flexible gripping component 5 is adjusted to the corresponding position with the counterweight. Then, the gripping cylinder 56 is activated. The extension and retraction of the extended end of the gripping cylinder 56 causes the flexible finger joint 541 to rotate between the two triangular plates 53. The first rotating rod 57 and the second rotating rod 547 rotate within the first mounting block 55 and the second mounting block 546 according to the specific extension and retraction length of their extended ends, thus realizing the rotation of the flexible finger joint 541. Since each flexible finger joint 541 is controlled by an individual gripping cylinder 56, the rotation is achieved through air pressure regulation. The flexible knuckle 541 features continuous control over its bending angle, adapting to surfaces with different curvatures. This allows the flexible knuckle 541 to conform to different positions on the surfaces of various irregularly shaped counterweights. Simultaneously, a silicone sleeve 544 encases the counterweight surface. Then, an external vacuum system is activated, using a vacuum pipe 549 to evacuate the filling cavity 542. This vacuum process solidifies the granular medium 545. Under pressure differential, the silicone sleeve 544 contracts inward, compressing the granular medium 545, reducing the gaps between particles, and dramatically increasing friction. This creates a mechanical interlocking structure and forms a rigid gripper that completely conforms to the counterweight surface. The silicone sleeve 544, with its microporous structure, generates an adsorption force under vacuum, which helps to fix the position of the particulate medium 545 and prevents slippage. The silicone sleeve 544 enables non-destructive gripping. During the gripping process on the surface of the counterweight, the flexible knuckle 541 monitors the distribution of the gripping force in real time through the piezoresistive sensor array 543 integrated on the surface of the flexible knuckle 541, preventing overload damage to the counterweight or insufficient gripping, and avoiding damage to the surface of the counterweight caused by the gripping of traditional mechanical structures. After gripping, the linear guide rail 2 drives the robotic arm assembly 4 to move linearly to the designated position, completing the loading and unloading operation of the counterweight.

[0033] It is understood that the present invention has been described through some embodiments, and those skilled in the art will recognize that various changes or equivalent substitutions can be made to these features and embodiments without departing from the spirit and scope of the invention. Furthermore, under the teachings of the present invention, these features and embodiments can be modified to adapt to specific situations and materials without departing from the spirit and scope of the invention. Therefore, the present invention is not limited to the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application are within the protection scope of the present invention.

Claims

1. A flexible loading and unloading device for a washing machine counterweight, comprising a belt conveyor (1) and a linear guide rail (2) installed at one end thereof, characterized in that: The top of the linear guide rail (2) is provided with a base (3), and the top of the base (3) is provided with a robotic arm assembly (4) for realizing multi-axis movement of the loading and unloading device. The end of the robotic arm assembly (4) away from the base (3) is provided with a flexible gripping assembly (5) for gripping the counterweight. The end of the base (3) is provided with a 3D vision sensor (6) for identifying the position of the counterweight. The flexible gripping component (5) includes a connector (51) connected to the robotic arm component (4). The bottom end of the connector (51) is provided with two support frames (52). Several triangular plates (53) are fixedly connected to the middle of the support frames (52). A gripper component (54) is rotatably connected between each pair of adjacent triangular plates (53). The gripper assembly (54) includes a flexible knuckle (541), a filling cavity (542) is provided on one side of the inner cavity of the flexible knuckle (541), a piezoresistive sensor array (543) is provided on one side of the inner wall of the flexible knuckle (541), a silicone sleeve (544) is provided on the other side of the inner wall of the flexible knuckle (541), and the inner cavity of the filling cavity (542) is filled with particulate medium (545).

2. The flexible loading and unloading device for a washing machine counterweight according to claim 1, characterized in that: One end of the support frame (52) is fixedly connected to a plurality of first mounting blocks (55), and a gripping cylinder (56) is mounted on the first mounting block (55). The output end of each gripping cylinder (56) corresponds to a gripper assembly (54). A first rotating rod (57) is rotatably connected to the middle of the first mounting block (55), and is rotatably connected to the gripping cylinder (56) through the first rotating rod (57).

3. The flexible loading and unloading device for a washing machine counterweight according to claim 2, characterized in that: A second mounting block (546) is fixedly connected to the upper part of the outer surface of the flexible knuckle (541), and a second rotating rod (547) is rotatably connected to the middle part of the second mounting block (546). The extended end of the gripping cylinder (56) is fixedly connected to the middle part of the second rotating rod (547).

4. The flexible loading and unloading device for a washing machine counterweight according to claim 1, characterized in that: A limiting ring (548) is fixedly connected to the middle of the outer surface of the flexible joint (541), and a vacuum pipe (549) is fixedly connected to the lower part of the outer surface of the flexible joint (541). One end of the vacuum pipe (549) is connected to the filling cavity (542), and the other end of the vacuum pipe (549) is connected to the input end of an external vacuum device.

5. A flexible loading and unloading device for a washing machine counterweight according to claim 1, characterized in that: The robotic arm assembly (4) includes a connecting shaft (41) located at the top of the base (3). A rear upper arm (42) is rotatably connected to the top of the connecting shaft (41). A front upper arm (43) is rotatably connected to the end of the rear upper arm (42) away from the connecting shaft (41). A telescopic arm (44) is provided at the end of the front upper arm (43) away from the rear upper arm (42). A connecting frame (45) is fixedly connected to the extended end of the telescopic arm (44). A connecting wrist (46) is rotatably connected to the inner cavity of the connecting frame (45).

6. The flexible loading and unloading device for a washing machine counterweight according to claim 5, characterized in that: The top end of the connector (51) is rotatably connected to the connecting wrist (46). The inner cavity of the connecting frame (45) is provided with a drive motor for driving the connector (51) to rotate. The output end of the drive motor passes through the connecting frame (45) and is fixedly connected to the top end of the connector (51).

7. A flexible loading and unloading device for a washing machine counterweight according to claim 5, characterized in that: The base (3) has a drive motor in the middle of its inner cavity for driving the connecting shaft (41) to rotate. The connecting shaft (41) is connected to the rear arm (42) and the rear arm (42) is connected to the front arm (43). The front arm (43) is connected to the telescopic arm (44) at one end away from the telescopic arm (44) and a drive cylinder is provided for driving the telescopic arm (44) to extend and retract.

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