Industrial robot arm joint cutting system

Abstract

This invention discloses an industrial robot arm joint cutting system. The system includes a robotic arm, a transmission arm, and a switching component. A base is positioned beneath the robotic arm, and the transmission arm is housed inside the robotic arm. The switching component is located at the end effector of the robotic arm. Several sets of reflectors are installed within the transmission arm, which alters the direction of light transmission. The switching component switches the end effector. The robotic arm has a hollow structure, significantly reducing its weight and minimizing the impact of inertia on the robotic arm's movement, thereby improving its positioning and cutting accuracy.

Description

Technical Field

[0001] This invention relates to the field of cutting technology, specifically to an industrial robot arm joint cutting system. Background Technology

[0002] Laser cutting is a new type of thermal cutting technology with many advantages, such as high cutting speed, high production efficiency, good cutting end face quality, small heat-affected zone, and environmental friendliness. Laser cutting has become one of the main methods of metal cutting, and its application is becoming more and more widespread.

[0003] In laser cutting equipment, multi-jointed laser guide arms are typically used, positioned outside the robotic arm with only the front end attached. The laser beam is transmitted through the laser guide arm. During processing, especially when operated by a robotic arm, the guide arm adjusts its posture according to the arm's movement. All the power for the guide arm's movement comes from the front end, and the other parts of the arm rotate at multiple angles due to the traction of the front end, thus reducing the guide arm's flexibility.

[0004] In existing laser cutting technologies, the robotic arms used are primarily employed for material handling and welding. Handling and welding require stable and fast movements, resulting in designs that are typically large and heavy. However, when applied to laser applications, the non-contact cutting method—where the cutting head carries the laser beam—needs high positioning and repeatability accuracy. Weight and stability requirements are less stringent to ensure accurate cutting trajectories. However, the weight of traditional robotic arms often leads to inertia and torque effects during movement, resulting in lower positioning and repeatability accuracy. Consequently, cutting with traditional robotic arms results in significant errors, and current laser cutting robotic arms cannot meet the demands of high-quality cutting. Summary of the Invention

[0005] The purpose of this invention is to provide an industrial robot arm joint cutting system to solve the problems mentioned in the background art.

[0006] To solve the above-mentioned technical problems, the present invention provides the following technical solution: an industrial robot arm joint cutting system, the cutting system including a robot arm, a transmission arm, and a switching component. A base is provided below the robot arm, and a transmission arm is provided inside the robot arm. The switching component is located at the end effector of the robot arm. Several sets of reflectors are provided inside the transmission arm. The transmission arm changes the direction of light path transmission, and the switching component switches the end effector. The robotic arm has a hollow structure, which greatly reduces its weight and minimizes the impact of inertia on its movement, improving its positioning and cutting accuracy. A switching component switches the actuators at the end effector of the robotic arm. When processing small workpieces, the robotic arm uses a set of actuators with a small working range. When processing large or tubular workpieces, the switching component changes the actuators, increasing the working range and radius. This also allows the robotic arm to perform circular cutting on tubular workpieces, fulfilling the requirement that existing robotic arms cannot perform circular cutting. The transfer arm is placed inside the robotic arm, allowing it to adjust its position as the robotic arm rotates, thus improving its flexibility. This avoids the limitations of having the transfer arm outside the robotic arm, which would restrict its flexibility, and also reduces the space constraints associated with externally placed transfer arms.

[0007] The switching assembly includes a flange, a transfer cylinder, and an extension arm. The flange is located at the end effector of the robot arm, and the transfer cylinder is located on the other end face of the flange. One end of the transfer cylinder is connected to the pipe of the transfer arm, and the extension arm is located below the transfer cylinder. One end of the extension arm is rotatably connected to the flange, and both the other ends of the extension arm and the transfer cylinder are equipped with focusing tubes. The flange provides support for the installation of the transfer cylinder and is connected to the rotary motor at the end of the robot arm. The flange rotates to switch the end effector. The transfer cylinder transmits the light path. The extension arm is installed below the transfer cylinder. When the light path is redirected, it is transmitted through the extension arm and to its end. An actuator is installed at the end of the extension arm. By extending, the extension arm expands the working range and working radius of the robot arm. At the same time, the extension arm can be adjusted at various angles to allow the robot arm to cut plates and round tubes of different sizes. The focusing tube is the end effector. The focusing tube concentrates and combines the light path. Driven by the robot arm, the focusing tube cuts the workpiece through laser output.

[0008] The lower end of the transmission cylinder is provided with a connecting pipe; the extension arm includes a first extension arm, three sets of extension joints, a second extension arm, and a third extension arm. One end of the first extension arm is rotatably connected to a flange. The two ends of one set of extension joints are respectively fixed to the other ends of the first extension arm and one end of the second extension arm. The two ends of another set of extension joints are respectively fixed to the other ends of the second extension arm and one end of the third extension arm. One end of the remaining set of extension joints is fixed to the other end of the third extension arm. A focusing tube is provided at the other end of the remaining set of extension joints. A connecting channel is provided on the first extension arm at the position corresponding to the connecting pipe. When the extension arm extends, the connecting pipe connects to the pipe of the first extension arm through the connecting channel and redirects the light path into the extension arm, allowing the light path to be transmitted in the extension arm. Through the mutual cooperation of the first extension arm, the second extension arm, the third extension arm, and the extension joints, the extension arm can rotate 360° in space, enabling the extension arm to process the workpiece from multiple angles.

[0009] Reflectors are installed inside both ends of the extension joint, forming a cooling space in conjunction with the internal space of the extension joint and the reflectors. A heat exchange plate is installed on the back of the reflector, with a groove in the center of the heat exchange plate. A steering bearing is installed in the groove, and several sets of cooling plates are installed on the other side of the steering bearing. When the reflector participates in the reflection of light, it absorbs a small amount of energy, which causes the reflector temperature to rise. By generating cold air in the cooling space, the reflector is cooled. The cooling space is a closed space, so there is no need for heat exchange with the outside environment, thus preventing dust from the outside air from contaminating the reflector surface. The heat exchange plate absorbs the temperature from the reflector and exchanges heat with the several sets of cooling plates. Each cooling plate is equipped with a cooling fin. The cooling plates are energized to cool the cooling plates and the air in the cooling space. The several sets of cooling plates are mounted on the steering bearing and rotate in the groove through the steering bearing. When the extension arm is working, the cooling plates rotate in the cooling space through the steering bearing, and the rotation agitates the air in the cooling space, mixing the hot and cold air and accelerating the cooling of the reflector.

[0010] Several sets of support feet are provided on the end face of the heat exchange plate that contacts the reflector. These support feet create ventilation gaps between the heat exchange plate and the reflector. Each set of cooling plates has a counterweight plate at its lower end. The cooling plates are kept vertical by the counterweight plates. The counterweight plates, in conjunction with the steering bearing, allow the cooling plates to rotate during the operation of the extension arm. Due to the rising of hot air, the air in the ventilation gaps becomes relatively thin. When the cooling plates rotate in the cooling space, they cause the gas in the cooling space to flow. This rotation allows a small amount of cold air from the bottom of the cooling space to enter the ventilation gaps, causing the hot and cold air to mix and cool down. This reduces the air pressure in the ventilation gaps, thereby accelerating the flow rate of cold air entering the ventilation gaps when the cooling plates rotate, improving the cooling effect on the reflector.

[0011] Lifting blocks are installed on both sides of the lower end of the connecting tube, and two sets of dustproof plates are installed inside the lower end of the connecting tube. The lifting blocks are slidably connected to the connecting tube, and the lifting blocks are rotatably connected to the dustproof plates. Two sets of sealing plates are installed in the connecting channel. A steering rod is installed inside the first extension wall on the outside of each set of sealing plates. A connecting rod is installed at the other end of each set of steering rods, and the other end of the connecting rod is rotatably connected to the sealing plate. The dustproof plates seal the connecting tube. When the extension arm rotates and connects with the connecting tube, the connecting tube is inserted into the connecting channel. At the same time, the lifting blocks are pushed up on the connecting tube by the first extension arm. The lifting blocks pull the dustproof plates through the connecting rod, causing the dustproof plates to rotate inside the connecting tube, thereby opening the connecting tube. Simultaneously, the sealing plates move downward in the connecting channel under the push of the connecting tube and move to both sides under the traction of the rotating rod, thereby opening the connecting channel and allowing the light path to enter the first extension arm.

[0012] A reversing mirror is installed inside the transmission cylinder above the connecting pipe. A reversing cylinder is installed on the transmission cylinder above the reversing mirror. One end of the reversing cylinder is rotatably connected to the reversing mirror, and a pressure valve is installed inside the reversing cylinder at the end away from the reversing mirror. When the end effector needs to be replaced, gas is injected into the reversing cylinder. At the same time, the pressure valve increases the pressure in the reversing cylinder. When the gas pressure reaches the set value, the pressure valve opens, allowing a large amount of gas to instantly enter the reversing cylinder and push the piston. This causes the reversing cylinder to quickly push the reversing mirror, thereby achieving rapid rotation of the reversing mirror. Through the rotation of the reversing mirror, the optical path is switched, allowing the optical path to enter the connecting pipe and then re-enter the first extension arm, thus realizing the switching of the end effector.

[0013] The transmission arm is composed of a first transmission arm, a transmission joint, a second transmission arm, a transmission joint, and a third transmission arm connected in sequence. The other end of the third transmission arm is rotatably connected to the transmission cylinder. Reflectors are provided at both ends of the two sets of transmission joints.

[0014] Compared with the prior art, the beneficial effects achieved by the present invention are:

[0015] 1. The robotic arm has a hollow structure, which greatly reduces the weight of the arm, reduces the impact of inertia on the robotic arm during movement, and improves the positioning and cutting accuracy of the robotic arm.

[0016] 2. The transfer arm is placed inside the robot arm, so that the position of the transfer arm can be adjusted as the robot arm rotates, realizing the flexibility of the transfer arm. At the same time, it avoids the impact on the working flexibility of the robot arm if the transfer arm is located outside the robot arm, and also reduces the large space restrictions caused by placing the transfer arm outside.

[0017] 3. By switching the actuators, the working range and radius of the robot arm are increased. At the same time, the robot arm can perform circular cutting on tubular workpieces, thereby meeting the robot arm's requirement for circular cutting of workpieces.

[0018] 4. By generating cold air in the cooling space, the reflector is cooled. The cooling space is a closed space, so there is no need for heat exchange with the outside world, thus preventing dust in the outside air from contaminating the reflector surface.

[0019] 5. The heat exchange plate absorbs the temperature on the reflector and exchanges heat with several sets of cooling plates. Each cooling plate is equipped with a cooling fin. The cooling plates are energized to cool the air in the cooling space. Several sets of cooling plates are mounted on steering bearings and rotate in grooves through the steering bearings. When the extension arm is working, the cooling plates rotate in the cooling space through the steering bearings, and the rotation agitates the air in the cooling space, mixing the hot and cold air, thereby accelerating the cooling of the reflector.

[0020] 6. The cooling plate is kept vertical by a counterweight. The counterweight and the steering bearing work together to make the cooling plate rotate when the extension arm is working. As the hot air rises, the air in the ventilation gaps becomes relatively thin. When the cooling plate rotates in the cooling space, it drives the air flow in the cooling space. The rotation causes a small amount of cold air at the bottom of the cooling space to enter the ventilation gaps, causing the hot and cold air to mix and cool down. This reduces the air pressure in the ventilation gaps, thereby accelerating the flow rate of cold air into the ventilation gaps when the cooling plate rotates, and improving the cooling effect on the reflector. Attached Figure Description

[0021] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used together with the embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings:

[0022] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0023] Figure 2 This is a schematic diagram of the extended arm structure of the present invention;

[0024] Figure 3 This is a top view of the extension arm structure of the present invention;

[0025] Figure 4 This is a schematic diagram of the internal structure of the extended joint of the present invention;

[0026] Figure 5 This is a schematic diagram of the transmission arm of the present invention;

[0027] Figure 6 This is the invention Figure 2 Schematic diagram of the structure of region A in the middle;

[0028] Figure 7 This is a schematic diagram of the internal structure of the connecting tube of the present invention;

[0029] Figure 8 This is a schematic diagram of the internal structure of the first extension arm of the present invention;

[0030] Figure 9 This is the invention Figure 8 A schematic diagram of the structure of region B in the middle.

[0031] In the diagram: 1. Base; 2. Robotic arm; 3. Transfer arm; 4. Switching component; 5. Reflector; 3-1. First transfer arm; 3-2. Transfer joint; 3-3. Second transfer arm; 3-4. Third transfer arm; 4-1. Flange; 4-2. Transfer cylinder; 4-3. Concentrating tube; 4-4. Reversing cylinder; 4-5. Reversing mirror; 4-6. Connecting pipe; 4-7. Extension arm; 4-71. First extension arm; 4-72. Extension joint; 4-73. Second extension arm; 4-74. Third extension arm; 4-75. Heat exchange plate; 4-76. Cooling plate; 4-77. Counterweight plate; 4-78. Steering bearing; 4-61. Lifting block; 4-62. Dustproof plate; 4-711. Sealing plate; 4-712. Connecting rod; 4-713. Steering rod. Detailed Implementation

[0032] 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.

[0033] Please see Figure 1-9The present invention provides a technical solution: an industrial robot arm joint cutting system, which includes a robot arm 2, a transmission arm 3, and a switching component 4. A base 1 is rotatably mounted below the robot arm 2, and the transmission arm 3 is fixedly mounted inside the robot arm 2. The switching component 4 is installed at the end of the robot arm 2. Several sets of reflectors 5 are installed inside the transmission arm 3. The transmission arm 3 changes the direction of light transmission, and the switching component 4 switches the end effector.

[0034] The transmission arm 3 is composed of a first transmission arm 3-1, a transmission joint 3-2, a second transmission arm 3-3, a transmission joint 3-2, and a third transmission arm 3-4 connected in sequence. The other end of the third transmission arm 3-4 is rotatably connected to the transmission cylinder 4-2. Both ends of the two sets of transmission joints 3-2 are equipped with reflectors 5. The first transmission arm 3-1 is connected to the laser generator.

[0035] The switching assembly 4 includes a flange 4-1, a transmission cylinder 4-2, and an extension arm 4-7. The flange 4-1 is mounted on the rotary motor at the end of the robot arm 2. The transmission cylinder 4-2 is fixedly mounted on the other end face of the flange 4-1 and is connected to the third transmission arm 3-4. The extension arm 4-7 is located below the transmission cylinder 4-2. One end of the extension arm 4-7 is rotatably connected to the flange 4-1. A focusing tube 4-3 is fixedly mounted on the other end of the extension arm 4-7 and the other end of the transmission cylinder 4-2. A focusing plate is installed inside the focusing tube 4-3 and a tapered tube is installed at the end.

[0036] A connecting pipe 4-6 is fixedly installed at the lower end of the transmission cylinder 4-2. The connecting pipe 4-6 is connected to the transmission cylinder 4-2. A reversing mirror 4-5 is rotatably installed inside the transmission cylinder 4-2 above the connecting pipe 4-6. A reversing cylinder 4-4 is fixed on the transmission cylinder 4-2 above the reversing mirror 4-5. One end of the reversing cylinder 4-4 is rotatably connected to the other end of the reversing mirror 4-5.

[0037] Lifting blocks 4-61 are slidably installed on both sides of the lower end of the connecting pipe 4-6. Two sets of dustproof plates 4-62 are rotatably installed inside the lower end of the connecting pipe 4-6. The lifting blocks 4-61 are slidably connected to the connecting pipe 4-6 through a sliding groove, and a telescopic plate is installed in the sliding groove to prevent dust from entering the connecting pipe 4-6. The lifting blocks 4-61 are rotatably connected to the dustproof plates 4-62 through a connecting rod.

[0038] A pressure valve is installed inside the reversing cylinder 4-4 at the end away from the reversing mirror 4-5. The pressure valve divides the inside of the reversing cylinder 4-4 into a pressure storage space and a piston space. When the pressure value inside the pressure storage space reaches the set value, the pressure valve opens, and a large amount of air instantly enters the piston space and pushes the piston, thereby causing the reversing mirror 4-5 to rotate rapidly inside the transmission cylinder 4-2, thus realizing the change of the transmission optical path.

[0039] The extension arm 4-7 includes a first extension arm 4-71, three sets of extension joints 4-72, a second extension arm 4-73, and a third extension arm 4-74. One end of the first extension arm 4-71 is rotatably connected to the flange 4-1, and a motor is installed at the rotatable connection. The two ends of one set of extension joints 4-72 are respectively fixed to the other end of the first extension arm 4-71 and one end of the second extension arm 4-73. The two ends of another set of extension joints 4-72 are respectively fixed to the other end of the second extension arm 4-73 and one end of the third extension arm 4-74. One end of the remaining set of extension joints 4-72 is fixed to the other end of the third extension arm 4-74. A focusing tube 4-3 is fixed to the other end of the remaining set of extension joints 4-72. A connecting channel is provided on the first extension arm 4-71 at the position corresponding to the connecting tube 4-6.

[0040] Motors are installed at the middle positions of the first extension arm 4-71, the second extension arm 4-73, the third extension arm 4-74, and the extension joint 4-72. The motors are DD motors with hollow structures.

[0041] Reflectors 5 are installed inside both ends of the extension joint 4-72. The interior of both ends of the extension joint 4-72 and the reflectors 5 cooperate to form a cooling space. A heat exchange plate 4-75 is fixed on the back of the reflector 5. There is a groove in the middle of the heat exchange plate 4-75. A directional bearing 4-78 is installed in the groove. Several sets of cooling plates 4-76 are fixed on the other side of the directional bearing 4-78.

[0042] Several sets of support feet are provided on the end face of the heat exchange plate 4-75 that contacts the reflector 5. The several sets of support feet form a ventilation gap between the heat exchange plate 4-75 and the reflector 5. A counterweight plate 4-77 is installed at the lower end of each of the several sets of cooling plates 4-76.

[0043] Two sets of sealing plates 4-711 are slidably installed in the connecting channel. Inside the first extension wall 4-71, a steering rod 4-713 is rotatably installed on the left and right sides of each set of sealing plates 4-711. A connecting rod 4-712 is rotatably installed on the other end of each set of steering rods 4-713. The other end of the connecting rod 4-712 is rotatably connected to the sealing plate 4-711.

[0044] The steering rod 4-713 is rotatably connected to the first extension arm 4-71 via a fixing pin and a torsion spring. There is a limitation on the rotation angle between the steering rod 4-713 and the first extension arm 4-71, so that the steering rod 4-713 cannot rotate after rotating a certain angle.

[0045] The steering rod 4-713 is rotatably connected to the connecting rod 4-712 via a fixing pin and a torsion spring. There is a limitation on the rotation angle between the steering rod 4-713 and the first extension arm 4-71, so that the connecting rod 4-712 cannot rotate after rotating a certain angle relative to the steering rod.

[0046] Working principle of the invention:

[0047] When a workpiece needs to be cut, the machine generator transmits laser light into the transmission arm 3, so that the light path is transmitted in the transmission arm 3, and enters the focusing tube 4-3 through the transmission tube 4-2, and is emitted from the end of the focusing tube 4-3, thereby processing the workpiece.

[0048] When large plate-shaped or tubular workpieces need to be cut in a ring, the end effector, i.e., the focusing tube 4-3, needs to be switched.

[0049] The motor rotates the extension arm 4-7 to the front end of the robot arm 2. The optical transmission channel is connected through the connection between the first extension arm 4-71 and the connecting tube 4-6. Air is injected into the reversing cylinder 4-4, which pushes the reversing mirror 4-5, causing the reversing mirror 4-5 to transfer the optical path to the connecting tube 4-6 and into the extension arm 4-7.

[0050] Through the flexible adjustment of the extension arms 4-7 and their cooperation with the robot arm 2, the circular cutting of large workpieces can be achieved.

[0051] 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.

[0052] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An industrial robot arm joint cutting system, characterized in that: The cutting system includes a robotic arm (2), a transmission arm (3), and a switching component (4). A base (1) is provided below the robotic arm (2), and a transmission arm (3) is provided inside the robotic arm (2). The switching component (4) is located at the execution end of the robotic arm (2). Several sets of reflectors (5) are provided inside the transmission arm (3). The transmission arm (3) changes the direction of light transmission, and the switching component (4) switches the end effector. The switching assembly (4) includes a flange (4-1), a transmission cylinder (4-2), and an extension arm (4-7). The flange (4-1) is located at the execution end of the robot arm (2). The transmission cylinder (4-2) is located on the other end face of the flange (4-1). One end of the transmission cylinder (4-2) is connected to the pipeline of the transmission arm (3). The extension arm (4-7) is located below the transmission cylinder (4-2). One end of the extension arm (4-7) is rotatably connected to the flange (4-1). The other end of the extension arm (4-7) and the other end of the transmission cylinder (4-2) are both equipped with a focusing tube (4-3). The lower end of the transmission tube (4-2) is provided with a connecting tube (4-6); the extension arm (4-7) includes a first extension arm (4-71), three sets of extension joints (4-72), a second extension arm (4-73), and a third extension arm (4-74). One end of the first extension arm (4-71) is rotatably connected to the flange (4-1). The two ends of one set of extension joints (4-72) are respectively fixed to the other end of the first extension arm (4-71) and one end of the second extension arm (4-73). The two ends of another set of extension joints (4-72) are respectively fixed to the other end of the second extension arm (4-73) and one end of the third extension arm (4-74). One end of the remaining set of extension joints (4-72) is fixed to the other end of the third extension arm (4-74). The other end of the remaining set of extension joints (4-72) is provided with a focusing tube (4-3). A connecting channel is provided on the first extension arm (4-71) at the position corresponding to the connecting tube (4-6). The interior of both ends of the extension joint (4-72) is provided with a reflector (5). The interior of both ends of the extension joint (4-72) and the reflector (5) cooperate with each other to form a cooling space. A heat exchange plate (4-75) is provided on the back of the reflector (5). A groove is provided in the middle of the heat exchange plate (4-75). A steering bearing (4-78) is provided in the groove. Several sets of cooling plates (4-76) are provided on the other side of the steering bearing (4-78). The cooling plates (4-76) and the air in the cooling space are cooled by energizing them. Several sets of support feet are provided on the side end face of the heat exchange plate (4-75) that contacts the reflector (5). The several sets of support feet form a ventilation gap between the heat exchange plate (4-75) and the reflector (5). The lower end of the several sets of cooling plates (4-76) is provided with a counterweight plate (4-77). Inside the transmission cylinder (4-2), above the connecting pipe (4-6), a reversing mirror (4-5) is rotatably mounted. A reversing cylinder (4-4) is set on the transmission cylinder (4-2) above the reversing mirror (4-5). One end of the reversing cylinder (4-4) is rotatably connected to the reversing mirror (4-5). A pressure valve is set inside the end of the reversing cylinder (4-4) away from the reversing mirror (4-5).

2. The industrial robot arm joint cutting system according to claim 1, characterized in that: The transmission arm (3) is composed of a first transmission arm (3-1), a transmission joint (3-2), a second transmission arm (3-3), a transmission joint (3-2), and a third transmission arm (3-4) connected in sequence. The other end of the third transmission arm (3-4) is rotatably connected to the transmission cylinder (4-2). Both ends of the two sets of transmission joints (3-2) are provided with reflectors (5).

3. The industrial robot arm joint cutting system according to claim 1, characterized in that: Lifting blocks (4-61) are provided on both sides of the lower end of the connecting pipe (4-6); two sets of dustproof plates (4-62) are rotatably connected inside the lower end of the connecting pipe (4-6); the lifting blocks (4-61) are slidably connected to the connecting pipe (4-6); the lifting blocks (4-61) are rotatably connected to the dustproof plates (4-62) through connecting rods; two sets of sealing plates (4-711) are slidably installed in the connecting channel; a steering rod (4-713) is rotatably installed inside the first extension arm (4-71) on the outside of each set of sealing plates (4-711); a connecting rod (4-712) is rotatably installed at the other end of each set of steering rods (4-713); the other end of the connecting rod (4-712) is rotatably connected to the sealing plate (4-711).

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