Plastic bag production device with flattening function

Abstract

The invention provides a plastic bag production device with a flattening function, which belongs to the technical field of plastic bag production and comprises a base, a support rod and a fixing rod. According to the plastic bag flattening device, an arranged flattening rod is matched with a torsional spring to continuously roll and flatten a plastic bag through a flattening roller in the downward moving process, wrinkles and bubbles generated in the production process of the plastic bag are effectively eliminated, and an arranged positioning rod is matched with limiting shafts at the two ends of the flattening roller to always extrude and fix the plastic bag below in the flattening process; according to the plastic bag flattening device, the situation that a flattened and rolled plastic bag is pulled in the flattening process is effectively avoided, the overall flattening effect is improved, and a magnet arranged on one side of a fixing rod is matched with an iron block arranged on one side of a flattening rod, so that the situation that a flattening roller rolls in the opposite direction in the lifting process, and the plastic bag is wrinkled for the second time is avoided; and meanwhile, an abutting plate arranged on the side wall of the supporting rod is matched to release the leveling rod after lifting is finished, and it is guaranteed that follow-up leveling work is not affected.

Description

Technical Field

[0001] The invention relates to the technical field of plastic bag production, and in particular to a plastic bag production device with a flattening function. Background Art

[0002] Plastic bags are bags made of plastic as the main raw material. They are essential items in people's daily lives and are often used to hold other items. They are widely used because of their cheapness, extremely light weight, large capacity, and easy storage. Plastic bag rolls are a common packaging material, mainly used for commercial and household purposes. They are usually made of plastics such as polyethylene (PE) and are lightweight, durable, and easy to use. There are many types of plastic bag rolls, including supermarket-specific roll bags, food-grade household fresh-keeping bags, thickened vest-style fresh-keeping bags, etc. These products are designed according to different needs and usage scenarios to meet various packaging needs. Many plastic bag rolls are designed with a dotted hand-tear mouth to facilitate users to quickly take bags of the required length.

[0003] In the prior art, in the existing plastic bag production process, due to the uneven thickness and tension of the plastic film, the surface of the produced plastic bag often has wrinkles, bubbles and other defects, which affects the appearance and quality of the product. How to invent a plastic bag production device with a flattening function to solve these problems has become an urgent problem to be solved by those skilled in the art. Summary of the invention

[0004] In order to make up for the above deficiencies, the present invention provides a plastic bag production device with a flattening function, aiming to solve the problem of wrinkles and bubbles appearing on the surface of the plastic bags after production.

[0005] The present invention is achieved in that:

[0006] The present invention provides a plastic bag production device with a flattening function, comprising a base, a support rod and a fixing rod arranged on the base, the outer wall of the base is provided with two groups of mutually symmetrical first ear plates and second ear plates, one group of the first ear plates is provided with a winding roller between them, the outer wall of the first ear plates is provided with a motor, the other group of the first ear plates is provided with an unwinding roller between them, and a tightening roller is provided between the second ear plates;

[0007] One end of the two support rods is fixedly connected to the outer wall of the base, a fixing plate is installed on the upper end of the support rod, and a hydraulic rod is installed on the upper side wall of the fixing plate;

[0008] The upper side wall of the fixed rod is fixedly connected to the telescopic end of the hydraulic rod, and the lower side wall of the fixed rod is installed with four mounting sleeves in groups of two, and the interior of the mounting sleeve is provided with a mounting groove, and a leveling rod is installed on the outer wall between the two mounting sleeves, and a rotating shaft extending into the interior of the mounting groove is installed on the side wall of the leveling rod, and a torsion spring is installed on the outer wall of the rotating shaft, a leveling frame is installed at one end of the leveling rod, and a leveling roller is installed on the inner wall of the leveling frame.

[0009] Preferably, both ends of the winding roller are rotatably connected to the inner wall of the first ear plate, the output end of the motor is fixedly connected to one end of the winding roller, both ends of the unwinding roller are rotatably connected to the inner wall of another group of first ear plates, and both ends of the tensioning roller are rotatably connected to the inner wall of the second ear plate.

[0010] Preferably, a slide groove is provided on an outer wall of one side of the support rod, and sliding blocks slidably connected to the inner wall of the slide groove are installed at both ends of the fixing rod.

[0011] Preferably, the outer wall of the rotating shaft is rotatably connected to the inner wall of the mounting groove, the two ends of the torsion spring are respectively fixedly connected to the mounting sleeve and the side wall of the rotating shaft, the torsion spring makes the leveling rod perpendicular to the base in a normal state, and the two ends of the leveling roller are rotatably connected to the inner wall of the leveling frame.

[0012] By adopting the above technical scheme, the produced plastic bag is rolled and installed on the unwinding roller, and one end of the plastic bag is wound around the winding roller. When the plastic bag is flattened and re-stored, the hydraulic rod is started to move the fixed rod at the lower end downward, and the side wall of the flattening roller is against the outer wall of the plastic bag. In the process that the fixed rod continues to move downward, the flattening rod on one side of the flattening roller pulls the torsion spring to rotate, and the flattening roller rolls to both sides of the plastic bag. By rolling contact with the plastic bag, the contact friction is reduced, and higher flatness can be provided. Wrinkles and bubbles generated in the production process of the plastic bag can be effectively eliminated, ensuring the smooth surface of the plastic bag and improving the flattening effect. At the same time, during the flattening process, the flattening rollers moving to both sides pull the middle position of the plastic bag that is not in contact to both sides for flattening, avoiding wrinkles in the position of the plastic bag that is not in contact with the flattening roller, thereby improving the flattening effect.

[0013] Preferably, symmetrical guide rods are installed on the inner wall of the fixing plate, and a positioning rod is installed at one end of each group of guide rods.

[0014] Preferably, a limiting groove is provided on the side wall of the positioning rod close to the leveling roller, and limiting shafts movably connected to the inner wall of the limiting groove are installed at both ends of the leveling roller.

[0015] By adopting the above technical solution, in the process of the fixed rod driving the leveling roller downward to level the plastic bag, when the leveling roller contacts the plastic bag, the positioning rods on both sides of the leveling roller simultaneously abut against the two ends of the plastic bag, and when the leveling roller moves subsequently, the guide rod slides on the inner wall of the fixed plate, so that the positioning rod at its bottom abuts against the upper surface of the plastic bag for fixation, and at the same time ensures that the positioning rod does not deviate in the horizontal direction, so that the bottom end can completely contact the plastic bag to improve the fixing effect. The subsequent leveling roller moves in the limiting groove through the limiting shaft during the leveling process, so as to keep the positioning rod fixed during the leveling process, so that the plastic bag at that position can be positioned to avoid pulling the plastic bag that has been leveled and rolled during the leveling process, thereby improving the overall leveling effect.

[0016] Preferably, abutment plates are installed on the side walls of the support rods, and the side walls and the abutment plates are rollingly connected when the leveling rollers are retracted upwards.

[0017] Preferably, symmetrical magnets are installed on the outer walls of both sides of the fixing rod close to the mounting sleeve, a fixing shaft is installed on the side wall of the leveling rod, and an iron block magnetically connected to the magnet is installed at one end of the fixing shaft.

[0018] By adopting the above technical solution, after the plastic bag is leveled once, in order to prevent the leveling rollers from getting close to each other and pulling the plastic bag toward the center position to cause wrinkles during the lifting process, the two are directly contacted and fixed by magnetic attraction under the action of the magnet on the fixing rod and the iron block on the leveling rod, thereby ensuring that the angle of the leveling rod is fixed. At the same time, in order to facilitate subsequent leveling, after lifting up to a certain height, the side wall of the leveling roller and the abutment plate of the side wall of the support rod are in contact. Continuing to lift the fixing rod will force the abutment plate to press against the leveling roller to fix it. At the same time, the fixing rod continues to lift to separate the magnet and the iron block. At the moment of separation, the entire leveling rod rebounds under the restoring force of the torsion spring, so that the leveling roller moves to its initial position, solving the problem of wrinkles in the plastic bag when the leveling rollers get close to each other during the lifting process, ensuring that the plastic bag does not produce secondary wrinkles after leveling, thereby improving the overall leveling effect of the plastic bag.

[0019] The beneficial effects of the present invention are:

[0020] The set leveling rod cooperates with the torsion spring to continuously roll and level the plastic bag through the leveling roller during the downward movement, effectively eliminating the wrinkles and bubbles generated in the plastic bag during the production process, ensuring the smooth surface of the plastic bag and improving the leveling effect. At the same time, the leveling rollers moving to both sides pull the uncontacted middle position of the plastic bag to both sides for leveling, avoiding wrinkles in the position of the plastic bag that does not contact the leveling roller and improving the leveling effect.

[0021] The positioning rod cooperates with the limit shafts at both ends of the leveling roller to squeeze and fix the plastic bag below during the leveling process, effectively avoiding pulling the plastic bag after leveling and rolling during the leveling process, and improving the overall leveling effect;

[0022] The magnet set on one side of the fixed rod cooperates with the iron block set on one side of the leveling rod to prevent the leveling roller from rolling in the opposite direction and causing secondary wrinkles to the plastic bag during the lifting process. At the same time, the support plate set on the side wall of the support rod releases the leveling rod after the lifting is completed, ensuring that subsequent leveling work is not affected. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0024] Figure 1 It is a schematic diagram of a plastic bag production device with a flattening function provided by an embodiment of the present invention;

[0025] Figure 2 It is a schematic diagram of the flattened structure of a plastic bag production device with a flattening function provided by an embodiment of the present invention;

[0026] Figure 3 It is a schematic diagram of a lifting structure after leveling of a plastic bag production device with a leveling function provided by an embodiment of the present invention;

[0027] Figure 4 A plastic bag production device with a flattening function provided by the embodiment of the present invention Figure 3 The structure of the middle A area should be the big picture;

[0028] Figure 5 It is a schematic structural diagram of a flattening component in a plastic bag production device with a flattening function provided by an embodiment of the present invention;

[0029] Figure 6 It is a cross-sectional view of the structure of a flattening component in a plastic bag production device with a flattening function provided by an embodiment of the present invention;

[0030] Figure 7 A plastic bag production device with a flattening function provided by the embodiment of the present invention Figure 6 A magnified view of the structure of the middle B area;

[0031] Figure 8 It is a half-section diagram of the structure of a flattening component in a plastic bag production device with a flattening function provided by an embodiment of the present invention;

[0032] Fig. 9 A plastic bag production device with a flattening function provided by the embodiment of the present invention Figure 8 Enlarged view of the structure of the middle C region.

[0033] In the figure: 1. base; 2. first ear plate; 21. winding roller; 22. unwinding roller; 23. motor; 24. second ear plate; 25. tensioning roller; 3. support rod; 31. slide groove; 32. abutment plate; 4. fixed plate; 41. hydraulic rod; 5. fixed rod; 51. slider; 52. magnet; 6. mounting sleeve; 61. mounting groove; 7. leveling rod; 71. rotating shaft; 72. torsion spring; 73. fixed shaft; 74. iron block; 8. leveling frame; 9. leveling roller; 91. limit shaft; 10. positioning rod; 101. limit groove; 102. guide rod. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0035] Example, see Figure 1-Figure 9 A plastic bag production device with a flattening function comprises a base 1 and a support rod 3 and a fixing rod 5 arranged on the base 1. Two groups of mutually symmetrical first ear plates 2 and second ear plates 24 are installed on the outer wall of the base 1. A winding roller 21 is installed between one group of the first ear plates 2, and a motor 23 is installed on the outer wall of the first ear plates 2. An unwinding roller 22 is installed between the other group of the first ear plates 2, and a tightening roller 25 is installed between the second ear plates 24.

[0036] One end of the two support rods 3 is fixedly connected to the outer wall of the base 1, a fixing plate 4 is installed on the upper end of the support rod 3, and a hydraulic rod 41 is installed on the upper side wall of the fixing plate 4;

[0037] The upper side wall of the fixed rod 5 is fixedly connected to the telescopic end of the hydraulic rod 41, and the lower side wall of the fixed rod 5 is installed with four mounting sleeves 6 in groups of two, and the interior of the mounting sleeves 6 is provided with mounting grooves 61, and a leveling rod 7 is installed on the outer wall between the two mounting sleeves 6, and a rotating shaft 71 extending into the interior of the mounting groove 61 is installed on the side wall of the leveling rod 7, and a torsion spring 72 is installed on the outer wall of the rotating shaft 71, a leveling frame 8 is installed at one end of the leveling rod 7, and a leveling roller 9 is installed on the inner wall of the leveling frame 8.

[0038] Furthermore, the two ends of the winding roller 21 are rotatably connected to the inner wall of the first ear plate 2, the output end of the motor 23 is fixedly connected to one end of the winding roller 21, the two ends of the unwinding roller 22 are rotatably connected to the inner wall of the other group of first ear plates 2, the two ends of the tensioning roller 25 are rotatably connected to the inner wall of the second ear plate 24, a slide groove 31 is provided on the outer wall of one side of the support rod 3, and sliders 51 slidably connected to the inner wall of the slide groove 31 are installed at both ends of the fixed rod 5, the outer wall of the rotating shaft 71 is rotatably connected to the inner wall of the mounting groove 61, the two ends of the torsion spring 72 are respectively fixedly connected to the mounting sleeve 6 and the side walls of the rotating shaft 71, and the torsion spring 72 makes the leveling rod 7 perpendicular to the base 1 in a normal state, and the two ends of the leveling roller 9 are rotatably connected to the inner wall of the leveling frame 8.

[0039] It should be noted that: the plastic bag roll after production is installed on the unwinding roller 22, and one end of it is wound around the winding roller 21. When the plastic bag is flattened and re-stored, the hydraulic rod 41 is started to move the fixed rod 5 at the lower end downward, and the side wall of the flattening roller 9 is against the outer wall of the plastic bag. In the process of the fixed rod 5 continuing to move downward, the flattening rod 7 on one side of the flattening roller 9 pulls the torsion spring 72 to rotate, and the flattening roller 9 rolls to both sides of the plastic bag. By rolling contact with the plastic bag, the contact is reduced to avoid friction, which can provide higher flatness, effectively eliminate wrinkles and bubbles generated in the production process of the plastic bag, ensure the smooth surface of the plastic bag, and improve the flattening effect. At the same time, during the flattening process, the flattening roller 9 moving to both sides pulls the middle position of the plastic bag that is not in contact to both sides for flattening, avoiding wrinkles in the position where the plastic bag does not contact the flattening roller 9, thereby improving the flattening effect.

[0040] Furthermore, symmetrical guide rods 102 are installed on the inner wall of the fixed plate 4, and a positioning rod 10 is installed at one end of each group of guide rods 102. A limiting groove 101 is provided on the side wall of the positioning rod 10 close to the leveling roller 9, and limiting shafts 91 movably connected to the inner wall of the limiting groove 101 are installed at both ends of the leveling roller 9.

[0041] It should be noted that: in the process of the fixed rod 5 driving the leveling roller 9 downward to level the plastic bag, when the leveling roller 9 contacts the plastic bag, the positioning rods 10 located on both sides of the leveling roller 9 simultaneously abut against the two ends of the plastic bag, and when the leveling roller 9 moves subsequently, the guide rod 102 slides on the inner wall of the fixed plate 4, so that the positioning rod 10 at the bottom end abuts against the upper surface of the plastic bag for fixation, and at the same time ensures that the positioning rod 10 does not deviate in the horizontal direction, so that the bottom end can completely contact the plastic bag to improve the fixing effect. The subsequent leveling roller 9 moves in the limiting groove 101 through the limiting shaft 91 during the leveling process, so as to keep the positioning rod 10 fixed during the leveling process, so that it can position the plastic bag at that position, avoid pulling the plastic bag after leveling and rolling during the leveling process, and improve the overall leveling effect.

[0042] Furthermore, the side wall of the support rod 3 is installed with a back plate 32, and the side wall and the back plate 32 are rollingly connected when the leveling roller 9 is retracted upward. Symmetrical magnets 52 are installed on the outer walls of both sides of the fixed rod 5 close to the mounting sleeve 6, and the side wall of the leveling rod 7 is installed with a fixed shaft 73, and one end of the fixed shaft 73 is installed with an iron block 74 magnetically connected to the magnet 52.

[0043] It should be noted that: after the plastic bag is flattened once, in order to prevent the flattening rollers 9 from getting close to each other and pulling the plastic bag toward the center to cause wrinkles during the lifting process, after the single flattening is completed, the magnet 52 on the fixing rod 5 and the iron block 74 on the flattening rod 7 are directly contacted and fixed by magnetic attraction, thereby ensuring that the angle of the flattening rod 7 is fixed. When the fixing rod 5 is subsequently lifted, the flattening roller 9 below will be driven to directly break away from the contact with the plastic bag upwards. At the same time, in order to facilitate the subsequent flattening, after being lifted up to a certain height, The side wall of the leveling roller 9 contacts the abutment plate 32 of the side wall of the support rod 3. Continuing to lift the fixing rod 5 will force the abutment plate 32 to press against the leveling roller 9 for fixation. At the same time, the fixing rod 5 continues to lift to separate the magnet 52 and the iron block 74. At the moment of separation, the entire leveling rod 7 rebounds under the restoring force of the torsion spring 72, so that the leveling roller 9 moves to its initial position, which solves the problem of wrinkles in the plastic bag when the leveling rollers 9 are close to each other during the lifting process, and ensures that the plastic bag does not produce secondary wrinkles after leveling, thereby improving the overall leveling effect of the plastic bag.

[0044] The working principle of the plastic bag production device with flattening function:

[0045] The produced plastic bag is rolled and installed on the unwinding roller 22, and one end of the plastic bag is wound on the winding roller 21. When the plastic bag is flattened and re-stored, the hydraulic rod 41 is started to move the fixed rod 5 at the lower end downward, and the side wall of the flattening roller 9 is against the outer wall of the plastic bag. When the flattening roller 9 contacts the plastic bag, the positioning rods 10 on both sides of the flattening roller 9 are against the two ends of the plastic bag at the same time. At the same time, when the flattening roller 9 moves subsequently, the guide rod 102 slides on the inner wall of the fixed plate 4, so that the positioning rod 10 at the bottom end is against the upper surface of the plastic bag for fixing, and at the same time, it is ensured that the positioning rod 10 does not deviate in the horizontal direction, so that the bottom end can be The complete contact with the plastic bag improves the fixing effect. The subsequent leveling roller 9 moves in the limiting groove 101 through the limiting shaft 91 during the leveling process, so as to keep the positioning rod 10 fixed during the leveling process, so that the plastic bag at that position can be positioned. At the same time, as the fixing rod 5 continues to move downward, the leveling rod 7 on one side of the leveling roller 9 pulls the torsion spring 72 to rotate, and the leveling roller 9 rolls to both sides of the plastic bag. By rolling contact with the plastic bag, the contact is reduced to avoid friction, which can provide higher flatness, effectively eliminate wrinkles and bubbles generated in the production process of the plastic bag, and ensure a smooth surface of the plastic bag. , improve the leveling effect, at the same time, during the leveling process, the leveling rollers 9 moving to both sides pull the middle position of the plastic bag that is not in contact to both sides for leveling, avoiding wrinkles in the position where the plastic bag does not contact the leveling rollers 9, and improving the leveling effect. After leveling the plastic bag once, the hydraulic rod 41 is started to lift the fixing rod 5. Under the action of the magnet 52 on the fixing rod 5 and the iron block 74 on the leveling rod 7, the two are directly contacted and fixed by magnetic attraction, thereby ensuring that the angle of the leveling rod 7 is fixed. When the fixing rod 5 is subsequently lifted, the leveling roller 9 below will be driven to directly break away from the contact with the plastic bag upwards. At the same time, in order to facilitate subsequent leveling, After being lifted up to a certain height, the side wall of the leveling roller 9 contacts the abutment plate 32 of the side wall of the support rod 3. Continuing to lift the fixing rod 5 will force the abutment plate 32 to press against the leveling roller 9 for fixation. At the same time, the fixing rod 5 continues to be lifted to separate the magnet 52 and the iron block 74. At the moment of separation, the entire leveling rod 7 rebounds under the restoring force of the torsion spring 72, so that the leveling roller 9 moves to its initial position. Then the motor 23 is started to drive the winding roller 21 to rotate, and the flattened plastic bag is rolled up and stored. The set leveling mechanism can effectively and continuously level the plastic bag, avoid bubbles in the plastic bag, and improve the quality of the product.

[0046] It should be noted that the specific model and specifications of the motor need to be selected and determined based on the actual specifications of the device, and the specific selection calculation method adopts the existing technology in this field, so it will not be described in detail.

[0047] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A plastic bag production device with a flattening function, comprising a base (1) and a support rod (3) and a fixing rod (5) arranged on the base (1), characterized in that: The outer wall of the base (1) is provided with two groups of mutually symmetrical first ear plates (2) and second ear plates (24), one group of which has a winding roller (21) installed between the first ear plates (2), and a motor (23) installed on the outer wall of the first ear plates (2), and the other group of which has an unwinding roller (22) installed between the first ear plates (2), and a tightening roller (25) installed between the second ear plates (24); One end of the two support rods (3) is fixedly connected to the outer wall of the base (1); a fixing plate (4) is installed on the upper end of the support rod (3); and a hydraulic rod (41) is installed on the upper side wall of the fixing plate (4); The upper side wall of the fixed rod (5) is fixedly connected to the telescopic end of the hydraulic rod (41); the lower side wall of the fixed rod (5) is installed with four mounting sleeves (6) in groups of two; a mounting groove (61) is provided inside the mounting sleeve (6); a leveling rod (7) is installed on the outer wall between the two mounting sleeves (6); a rotating shaft (71) extending into the mounting groove (61) is installed on the side wall of the leveling rod (7); a torsion spring (72) is installed on the outer wall of the rotating shaft (71); a leveling frame (8) is installed at one end of the leveling rod (7); and a leveling roller (9) is installed on the inner wall of the leveling frame (8).

2. A plastic bag production device with a flattening function according to claim 1, characterized in that: The two ends of the winding roller (21) are rotatably connected to the inner wall of the first ear plate (2), the output end of the motor (23) is fixedly connected to one end of the winding roller (21), the two ends of the unwinding roller (22) are rotatably connected to the inner wall of another group of first ear plates (2), and the two ends of the tensioning roller (25) are rotatably connected to the inner wall of the second ear plate (24).

3. A plastic bag production device with a flattening function according to claim 2, characterized in that: A sliding groove (31) is provided on one outer wall of the support rod (3), and sliding blocks (51) slidably connected to the inner wall of the sliding groove (31) are installed at both ends of the fixing rod (5).

4. A plastic bag production device with a flattening function according to claim 3, characterized in that: The outer wall of the rotating shaft (71) is rotatably connected to the inner wall of the mounting groove (61), and the two ends of the torsion spring (72) are respectively fixedly connected to the mounting sleeve (6) and the side wall of the rotating shaft (71). In a normal state, the torsion spring (72) makes the leveling rod (7) perpendicular to the base (1), and the two ends of the leveling roller (9) are rotatably connected to the inner wall of the leveling frame (8).

5. The plastic bag production device with a flattening function according to claim 1, characterized in that: Symmetrical guide rods (102) are installed on the inner wall of the fixing plate (4), and a positioning rod (10) is installed at one end of each group of guide rods (102).

6. A plastic bag production device with a flattening function according to claim 5, characterized in that: The positioning rod (10) is provided with a limiting groove (101) near the side wall of the leveling roller (9), and limiting shafts (91) movably connected to the inner wall of the limiting groove (101) are installed at both ends of the leveling roller (9).

7. The plastic bag production device with a flattening function according to claim 1, characterized in that: The side wall of the support rod (3) is installed with a stop plate (32), and when the leveling roller (9) is retracted upward, the side wall and the stop plate (32) are rollingly connected.

8. The plastic bag production device with a flattening function according to claim 7, characterized in that: Symmetrical magnets (52) are installed on the outer walls of both sides of the fixing rod (5) close to the mounting sleeve (6), a fixing shaft (73) is installed on the side wall of the leveling rod (7), and an iron block (74) magnetically connected to the magnet (52) is installed at one end of the fixing shaft (73).

Images