A method and auxiliary device for testing the non-dissolving antibacterial performance of the outer surface of a tube

Abstract

The present invention belongs to the field of antibacterial performance testing, and provides a method and an auxiliary device for testing the non-dissolving antibacterial property of the outer surface of a tube body, wherein the auxiliary device comprises a lower main body frame, on which a tube body placement area is provided; an upper main body frame, which is fixed directly above the lower main body frame and does not cover the tube body placement area; and a push block, which is in clearance fit with the lower main body frame. By using the designed auxiliary device, the tube body can be fixed as a wavy surface, so as to achieve the purpose of quantitatively and directly testing the non-dissolving antibacterial property of the tube body, which is an important supplement to the existing non-dissolving antibacterial testing method, and has great significance for improving the efficiency of antibacterial tube body research and development and future industrial quality control.

Description

Technical Field

[0001] The invention relates to a method for testing the non-dissolving antibacterial performance of the outer surface of a tube body and an auxiliary device, belonging to the field of antibacterial performance testing. Background Art

[0002] With the development of medical technology, inserting medical devices into the body for treatment has become a common medical method. Common interventional devices include indwelling needles, central venous catheters, urinary catheters and peritoneal dialysis tubes. After these medical device tubes are inserted into the human body for more than 7 days, bacteria / fungi will colonize on the outer and inner walls of the tubes and gradually form bacterial / fungal membranes, leading to an increasing risk of infection. Conventional treatment methods mainly require patients to take / inject antibacterial drugs to prevent and treat infections. The new generation of technology is to perform antibacterial modification on interventional medical device materials to delay / eliminate the occurrence of infections. The antibacterial modification of materials mainly includes two types of technologies: dissolution and non-dissolution. Among them, both sheet and tubular samples of dissolution antibacterial modified materials can be tested for dissolution antibacterial properties by the antibacterial ring method. However, dissolution antibacterial technology has the disadvantages of increasing the metabolic burden on patients and a high probability of forming drug resistance. Therefore, how to test and judge the pros and cons of the non-dissolution antibacterial performance of the tube body has become a key technical point in the research and development and production process.

[0003] The main antibacterial test methods for non-dissolving antibacterial modified materials are: (1) Film method, which is suitable for quantitative testing of the non-dissolving antibacterial properties of dense sheet materials, see GB / T 31402 "Test method for antibacterial properties of plastic surfaces" and WS / T650-2019 "Evaluation method for antibacterial and antibacterial effects"; (2) Quine method, which is suitable for quantitative testing of the non-dissolving antibacterial properties of fabrics and hard surface products, see FZ / T73023 "Antibacterial knitwear" D6 part and the 2002 edition of "Disinfection Technical Specifications" issued by the Ministry of Health; (3) Oscillation method, which is suitable for quantitative testing of non-dissolving antibacterial products, see FZ / T73023-2006 "Antibacterial knitwear" and WS / T650-2019 "Evaluation method for antibacterial and antibacterial effects"; (4) "Roll-Out" method, which is suitable for qualitative testing of the non-dissolving antibacterial properties of the outer surface of the tube, see the promotional material Infection Prevention with Certofix of German company Braun. Protect. If the first three methods require secondary molding or processing of the tube sample, for example, the tube material needs to be heated and pressed twice before the film method and Quine's method can be used, and it needs to be cut into smaller sheets before the oscillation method can be used. At the same time, the contact between the sample surface and bacteria / fungi in the oscillation method is far less sufficient than that of the film method and Quine's method, and the test results are more volatile. Among these methods, only the "Roll-Out" method can directly test the presence or absence of non-dissolving antibacterial properties on the outer surface of the tube body, but it can only qualitatively but not quantitatively measure the non-dissolving antibacterial properties.

[0004] The non-dissolving antibacterial property of the inner surface of the tube can be tested by injecting a certain amount of bacterial solution into the tube cavity, placing it horizontally for static culture, and inoculating the bacterial solution before and after static culture into the plate culture medium. The non-dissolving antibacterial property of the inner surface of the tube can be quantitatively tested by plate counting. Therefore, it is urgent to develop a test method for directly testing the non-dissolving antibacterial property of the outer surface of the tube to improve the efficiency of R&D testing and ensure the consistency and stability of the non-dissolving antibacterial performance of industrialized products. Summary of the invention

[0005] In view of the problem that the above test method cannot directly and quantitatively test the non-dissolving antibacterial performance of the outer surface of the tube body, the present invention designs a method and auxiliary device for testing the non-dissolving antibacterial performance of the outer surface of the tube body. The specific technical scheme is as follows:

[0006] A method for testing the non-dissolving antibacterial property of the outer surface of a tube, characterized in that the testing method comprises the following steps:

[0007] (1) Preparation of bacterial suspension and culture medium for the experiment. Take a small amount of pre-cultured bacteria and add them to the nutrient broth, mix thoroughly, and perform gradient dilution to the required concentration.

[0008] (2) Preparation of control tube, test tube and auxiliary device. Cut the disinfected / sterilized control tube and test tube into short tubes, and use auxiliary devices to fix multiple short tubes into a wavy surface to form a test module. Make the control tube test module and test tube test module required for the experiment.

[0009] (3) Sample inoculation. Place the test module of the tube to be tested and the control tube test module in sterile culture dishes respectively, drop the bacterial suspension onto the wavy surface of each test module, cover with a film, spread the bacterial liquid evenly around and prevent the bacterial liquid from overflowing the film, cover with the culture dish cover and culture for (24±1) h.

[0010] (4) Recovery of bacterial solution from the 0-time sample of the control tube and determination of the number of viable bacteria. After inoculation, the 0-time bacterial solution of the inoculated control tube test module is immediately eluted and recovered, SCDLP culture medium is added to the culture dish, and the wave surface is repeatedly rinsed with a pipette; the washed bacterial solution is aspirated and placed in the buffer solution to mix, and then gradient dilution is performed in sequence. The bacterial solution is aspirated from each test tube with different dilution multiples and placed in a sterile culture dish. Two sets of parallels are made for each dilution. Plate counting agar is poured into each culture dish, and gently shaken to evenly disperse the bacteria. It solidifies at room temperature, and then placed in a biochemical incubator for inverted culture, and the viable bacteria are counted.

[0011] (5) Recovery of bacterial solution and determination of viable bacterial count after incubation for (24±1) h. After incubating the test tube body test module inoculated with bacterial solution and the control tube body test module for (24±1) h, the bacterial solution was recovered and the viable bacterial count was counted using the same method as in (4).

[0012] (6) Calculation of viable bacteria. After the culture is completed, count the colonies in the culture dish and calculate the antibacterial test results.

[0013] (7) Calculation of antimicrobial activity value: If the test is considered effective, the antimicrobial activity value is calculated.

[0014] An auxiliary device for testing the non-dissolution antibacterial performance of the outer surface of a tube body, characterized in that it includes a lower main frame, on which a tube body placement area is provided; it also includes an upper main frame, which is fixed directly above the lower main frame and does not cover the tube body placement area; it also includes a push-in block, which is clearance-matched with the lower main frame.

[0015] As a further improvement of the device of the present invention, a rectangular groove is provided on the lower surface of the lower main frame near the end of the propulsion block, a sliding block is provided on the propulsion block that matches the rectangular groove, and the propulsion block is arranged in a "U-shape".

[0016] As a further improvement to the device of the present invention, a limiting platform higher than the upper end surface of the lower main frame is provided at the rear end of the lower main frame.

[0017] As a further improvement to the device of the present invention, the upper main frame is fixedly connected to the lower main frame by threads.

[0018] As a further improvement of the device of the present invention, the lower main body frame is provided with a propulsion thread groove near the end of the propulsion block, and the propulsion block is provided with a through hole corresponding to the propulsion thread groove.

[0019] As a further improvement of the device of the present invention, a recovery channel is provided between the upper main frame and the propulsion block.

[0020] As a further improvement of the device of the present invention, it is characterized in that an alignment baffle is provided on the side of the lower main body frame.

[0021] As a further improvement of the device of the present invention, it is characterized in that a hollow groove is provided inside the lower main body frame.

[0022] As a further improvement of the device of the present invention, the material of each component of the auxiliary device is metal or metal alloy.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] By using the test method and corresponding auxiliary device in the present invention, the tube body to be measured can be fixed as a wavy surface, and sample inoculation, live bacteria recovery, counting and other operations can be directly performed, thereby overcoming the drawback that the existing test methods can only indirectly quantitatively or directly qualitatively test the non-dissolving antibacterial properties of the tube body, thereby achieving the purpose of quantitatively and directly testing the non-dissolving antibacterial properties of the tube body. This is an important supplement to the existing non-dissolving antibacterial test methods, and is of great significance to improving R&D efficiency and future industrial quality control. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0026] Figure 1 This is a schematic diagram of the overall structure of an auxiliary device for testing the non-dissolution antibacterial performance of the outer surface of a tube body according to the present invention.

[0027] Figure 2 It is a schematic diagram of the lower main frame structure of the present invention.

[0028] Figure 3 It is a schematic diagram of the upper main frame structure of the present invention.

[0029] Figure 4 It is a schematic diagram of the structure of the propulsion card block in the present invention.

[0030] Figure 5 This is a top view of the overall structure of an auxiliary device for testing the non-dissolution antibacterial performance of the outer surface of a tube body according to the present invention.

[0031] Legend: 1. Upper main frame; 2. Lower main frame; 3. Dovetail fixing bolt; 4. Dovetail push bolt; 5. Push block; 6. Tube placement area; 7. Limit platform; 8. Hollow groove; 9. Push thread groove; 10. Alignment baffle; 11. Rectangular groove; 12. Fixed thread hole; 13. Through hole; 14. Long slider; 15. Short slider; 16. Recovery channel. DETAILED DESCRIPTION

[0032] The preferred embodiments of the present invention are further described in detail below in conjunction with the accompanying drawings of the specification. The following description is exemplary and not limiting of the invention. Any other similar situations also fall within the protection scope of the present invention.

[0033] like Figure 1As shown, an auxiliary device for testing the non-eluting antibacterial property of the outer surface of a tube body comprises a lower main frame 2, on which a tube body placement area 6 is provided; an upper main frame 1 is fixed directly above the lower main frame 2 and does not cover the tube body placement area 6; and a push block 5 is provided, wherein the push block 5 is clearance-matched with the lower main frame 2 and has a smooth surface for relative sliding.

[0034] like Figure 2 Figure 4 As shown, a rectangular groove 11 is provided on the lower surface of the lower main frame 2 near the end of the pushing block 5, and a slider matching with the rectangular groove 11 is provided on the pushing block 5, and the pushing block 5 is arranged in a "U-shape".

[0035] Preferably, in order to meet the requirement of fixing different numbers of tubes into modules, the two sliders of the pushing block 5 are respectively a long slider 14 and a short slider 15 .

[0036] like Figure 2 As shown, a limiting platform 7 higher than the upper end surface of the lower main frame 2 is provided at the rear end of the lower main frame 2 .

[0037] Furthermore, the upper main frame 1 and the lower main frame 2 are fixedly connected by threads.

[0038] Preferably, four fixing threaded holes are respectively arranged on the edges of the upper main frame 1 and the lower main frame 2, and four dovetail fixing bolts 3 are used for connection, so that the operation of fixing the test tube body is easier to perform.

[0039] like Figure 2 As shown, a propulsion thread groove 9 is provided at the end of the lower main frame 2 close to the propulsion block 5 , and a through hole 13 corresponding to the propulsion thread groove 9 is provided on the propulsion block 5 .

[0040] Preferably, the push thread groove 9 and the through hole 13 are both centrally arranged and connected using a dovetail push bolt 4 to facilitate the operation of driving the push block 5 to squeeze the test tube body.

[0041] like Figure 5 As shown, a recovery channel 16 is provided between the upper main frame 1 and the pushing block 5 .

[0042] Furthermore, an alignment baffle 10 is provided on the side of the lower main frame 2 .

[0043] Furthermore, two hollow grooves 8 are provided in the lower main frame 2, which can be used to detect whether there is leakage during the test process.

[0044] The material of each component of the auxiliary device is metal or metal alloy.

[0045] Preferably, in order to adapt to the high-pressure steam sterilization environment (121°C, 0.35MPa), the support rod (length 100mm) is made of tungsten steel, the main frame is made of aluminum alloy that has been anodized in its natural color, and the dovetail bolts are made of steel that has been rust-proofed.

[0046] The method of using the auxiliary device is as follows: according to the size of the inner diameter of the single-lumen tube to be tested, the outer diameter of the selected support rod should be slightly smaller than the inner diameter of the single-lumen tube. In this embodiment, the length of the support rod is 100 mm and the outer diameter is 1.1±0.01 mm; the length of the test tube body is consistent with the length of the support rod, and the support rod is inserted into the test tube body; the multiple support rods with the test tube body are placed in the tube body placement area 6 of the lower main frame 2, and the support rods with the tube body are aligned using the side alignment baffle 10; and four dovetail fixing bolts 3 are used to fix the upper main frame 1 and the support rods with the test tube body, as well as the lower main frame 2 together through the fixing threaded holes, but a slight looseness needs to be maintained. Afterwards, the push block 5 is placed in the rectangular groove 11, and the dovetail push bolt 4 is used to pass through the through hole 12 of the push block 5, and the dovetail push bolt 4 is screwed into the push thread groove 9 of the lower main frame 2. Finally, the dovetail push bolt 4 is rotated so that the push block 5 pushes the support rod with the test tube body to the limit platform 7. Since the push block 5 and the limit platform 7 play the role of front and rear limit, and the upper main frame 1 and the lower main frame 2 play the role of upper and lower limit, the test tube body with the support rod outside is closely contacted to ensure that the bacterial liquid does not leak out, forming a wavy test surface for the test of non-dissolution antibacterial activity value. As mentioned above, to test the non-dissolution antibacterial value of the outer surface of a single-lumen tube body with different inner diameters, it is only necessary to replace the support rods with different outer diameters to complete the test; if a multi-lumen tube body is tested, each inner cavity of the multi-lumen tube can also be inserted with a corresponding support rod according to this method to complete the above test.

[0047] A method for testing the non-dissolution antibacterial performance of the outer surface of a tube body comprises the following steps:

[0048] (1) Preparation of bacterial suspension and culture medium for the experiment

[0049] Under sterile conditions, use a metal inoculation loop to pick up a small amount of bacteria and transfer it to fresh culture medium, and place it in a (37±1)℃ biochemical incubator for 18h-24h. Use a sterile cotton swab to take a small amount of pre-cultured third-generation bacteria and add it to 9mL of fresh 1 / 500 nutrient broth and mix thoroughly. 8 CFU / mL turbidity tube was used for comparison and calibration, and then gradient dilution was performed in sequence to make the concentration of bacterial suspension about 6×10 5 CFU / mL.

[0050] (2) Preparation of control tube, test tube and auxiliary equipment

[0051] The control tube body is ordinary medical TPU, and the test tube body is a medical TPU tube doped with 0.5%, 1.0% and 1.5% nano ZnO, respectively. The control tube body and the test tube body are single-lumen tubes with an inner diameter of (1.1±0.01) mm and a wall thickness of 0.2 mm; the control tube body and the test tube body are cut into short tubes with a length of 100 mm, and the tube body is wiped with 75% medical ethanol for disinfection, and the auxiliary device is sterilized with high-pressure steam (121℃, 0.35MPa). Among them, the support rod (length 100mm) is made of tungsten steel, the main frame is an aluminum alloy with natural anodizing treatment, and the dovetail bolt is steel with rust prevention treatment; therefore, the auxiliary device can withstand high-temperature sterilization. Then, the support rod is inserted into the control tube body and the test tube body, and the auxiliary device is used to fix them into a square wave surface with an effective middle size of (50±5) mm×(50±5) mm to form a test module. Three TPU tube body test modules with ZnO contents of 0.5%, 1.0% and 1.5% were set (9 tube body test modules in total).

[0052] (3) Sample inoculation

[0053] Place the tube body test module to be tested and the control tube body test module in sterile culture dishes respectively, take 0.8mL of bacterial suspension and drop it on the wavy surface of each test module, cover it with a 40mm×40mm polyester film to spread the bacterial liquid evenly around and prevent the bacterial liquid from overflowing the film, cover the culture dish with a lid and culture it at a temperature of (35±1)℃ and a relative humidity of ≥90% for 24h.

[0054] (4) Recovery of bacterial solution from the control tube at time 0 and determination of viable bacterial count

[0055] After inoculation, the 3 groups of control tube test modules that have been inoculated were immediately eluted and recovered for 0 time. 10 mL of SCDLP culture medium was added to the culture dish, and the wave surface was repeatedly rinsed with a pipette for 1 min; 1 mL of the washed bacterial solution was taken and placed in 9 mL of NaCl peptone buffer solution and mixed thoroughly, and the volume of the bacterial solution was diluted 10, 100 and 1000 times in turn.

[0056] Pipette 1mL of bacterial solution from each test tube with different dilution multiples into a sterile culture dish. Make two parallel groups for each dilution. Pour about 20mL of plate counting agar into each culture dish. Shake gently to evenly disperse the bacterial solution. After solidifying at room temperature, place it in a (37±1)℃ biochemical incubator and invert it for 48h to count the live bacteria. The experiment shows that the bacterial solution diluted 1000 times can be used for effective counting and the statistics are included in the final summary table.

[0057] (5) Recovery of bacterial culture and determination of viable bacterial count after (24±1) h of culture

[0058] After culturing the tube body test module to be tested and the control tube body test module inoculated with bacterial solution for 24 hours, add 10mL SCDLP culture solution to the culture dish, and repeatedly rinse the wavy surface with a pipette for 1 minute; take 1mL of the washed bacterial solution and place it in 9mL NaCl peptone buffer solution to mix well, and dilute the volume of the bacterial solution by 10, 100, 1000 and 10000 times in turn.

[0059] Take 1mL of bacterial solution from each test tube of bacterial solution of different concentrations and put it into a sterile culture dish. Make two parallel groups for each bacterial solution concentration. Pour 20mL of plate counting agar into each culture dish and shake gently to evenly disperse the bacterial solution. After solidification at room temperature, put it into a (37±1)℃ biochemical incubator and invert it for 48h to count the live bacteria. The experiment shows that the bacterial solution cultured in the control tube can be diluted 10,000 times for effective counting, and the bacterial solution cultured in the test tube can be diluted by an appropriate multiple for effective counting, and the statistics are recorded in the final summary table.

[0060] (6) Calculation of viable bacteria count

[0061] After the culture is completed, the colonies in the culture dish are counted and the antibacterial test results are calculated:

[0062] N=(100×C×D×V) / A

[0063] Where: N—number of viable bacteria per square centimeter of each sample;

[0064] C—average colony count of 2 plates;

[0065] D—dilution multiple;

[0066] V- the volume of SCDLP culture medium used for elution, in mL;

[0067] A—Surface area of ​​the covering film, in mm 2 .

[0068] (7) Determination of test conditions

[0069] The average number of viable bacteria measured immediately after inoculation of the control tube at time 0 should be 1.2×10 4 ~ 5.0×10 4 Within the range, the logarithmic value of the number of viable bacteria should meet (L max -L min ) / L meam ≤0.2.

[0070] Where: L max ——The logarithmic value of the maximum number of viable bacteria on the control tube test module;

[0071] L min ——The logarithm value of the minimum number of viable bacteria on the control tube test module;

[0072] L mean ——The logarithm of the geometric mean viable count on the control tube test module.

[0073] In addition, the number of viable bacteria in each sample that has not been treated with antimicrobial agents after inoculation and culture for 24 hours should not be less than 62.

[0074] The bacterial count data measured at time 0 of the control tube are detailed in Example Data Summary Table 1, and all meet the above judgment conditions.

[0075] (8) Calculation of antibacterial activity value

[0076] In cases where the test is considered valid, the antimicrobial activity value is calculated:

[0077] R=(U t -U o )-(A t -U o )

[0078] R——antimicrobial activity value

[0079] U o ——The logarithmic mean of the bacterial count immediately after inoculation of the control tube test module;

[0080] U t ——The logarithmic mean of the bacterial count of the control tube test module 24 hours after inoculation;

[0081] A t ——The logarithmic mean of the bacterial count 24 hours after inoculation of the test module of the tube to be tested.

[0082] Table 1 Summary of data of the examples

[0083]

[0084] It can be understood that the above specific description of the present invention is only used to illustrate the present invention and is not limited to the technical solutions described in the embodiments of the present invention. Those skilled in the art should understand that the present invention can still be modified or replaced by equivalents to achieve the same technical effects; as long as the use requirements are met, they are within the protection scope of the present invention.

Claims

1. A method for testing the non-dissolving antibacterial property of the outer surface of a tube, characterized in that , including the following steps: (1) Prepare the bacterial suspension and culture medium for the test, wherein a small amount of pre-cultured bacteria is added to the nutrient broth and mixed thoroughly, and then graded diluted to the required concentration to obtain a bacterial suspension; (2) preparing a control tube body, a tube body to be tested and an auxiliary device; wherein the auxiliary device comprises an upper main frame (1), a lower main frame (2) and a push block (5); the lower main frame (2) is provided with a tube body placement area (6), and the rear end of the lower main frame (2) is provided with a limit platform (7) higher than the upper end surface of the lower main frame (2); the upper main frame (1) is fixed directly above the lower main frame (2) and does not cover the tube body placement area (6); the push block (5) and the lower main frame (2) are clearance-matched and can slide relative to each other; The disinfected or sterilized control tube body and the tube body to be tested are cut into a plurality of short tubes as test tube bodies, support rods are respectively inserted into the test tube bodies, and the support rods with the test tube bodies are placed in the tube body placement area (6) of the lower main frame (2) of the auxiliary device, and the support rods with the test tube bodies are pushed to the limit platform (7) by the pushing block (5) to play the role of front and rear limit, and the upper main frame (1) and the lower main frame (2) play the role of upper and lower limit, so that the test tube bodies with the support rods are in close contact with each other, and the plurality of short tubes are fixed into a wavy surface to form a test module for non-eluting antimicrobial activity value test, thereby manufacturing the control tube body test module and the test tube body test module required for the experiment; (3) Sample inoculation: Place the test module of the tube body to be tested and the control tube body test module in a sterile culture dish respectively, drop the bacterial suspension onto the wavy surface of each test module, cover it with a film, spread the bacterial suspension evenly around and prevent the bacterial suspension from overflowing the film, cover the culture dish with a lid and culture for 24±1h; (4) Recovery of bacterial solution from the 0-time sample of the control tube and determination of the number of viable bacteria: After inoculation, immediately elute and recover the 0-time bacterial solution from the inoculated control tube test module, add SCDLP culture medium to the culture dish, and repeatedly rinse the wavy surface with a pipette; aspirate the washed bacterial solution and place it in the buffer solution to mix evenly, and then perform gradient dilutions in sequence. Aspirate the bacterial solution from each test tube with different dilution multiples and place it in a sterile culture dish. Perform two parallel sets of dilutions for each dilution. Pour plate count agar into each culture dish, gently shake to evenly disperse the bacteria, solidify at room temperature, place it in a biochemical incubator for inverted culture, and count the viable bacteria; (5) Recovery of bacterial solution and determination of viable bacteria count after 24±1h of incubation: After incubating the test tube body test module inoculated with bacterial solution and the control tube body test module for 24±1h, the bacterial solution is recovered and the viable bacteria are counted using the same method as in step (4); (6) Calculating the antibacterial test results based on the viable bacterial count calculation results in steps (4) and (5); (7) If the test is considered effective, the antimicrobial activity value is calculated based on the viable bacterial count calculation results in steps (4) and (5).

2. According to the method of claim 1, an alignment baffle (10) is provided on the side of the lower main frame (2), and the alignment baffle (10) is used to align the support rods through which the test tube bodies are passed.

3. The method according to claim 1, characterized in that: The lower main body frame (2) is provided with a rectangular groove (11) on the lower surface of the end close to the push block (5), and the push block (5) is provided with a sliding block that matches the rectangular groove (11), and the push block (5) is arranged in a "U" shape.

4. The method according to claim 1, characterized in that: The upper main frame (1) is threadedly fixedly connected to the lower main frame (2).

5. The method according to claim 1, characterized in that The lower main body frame (2) is provided with a propulsion thread groove (9) near the end of the propulsion block (5), and the propulsion block (5) is provided with a through hole (13) corresponding to the propulsion thread groove (9).

6. The method according to claim 1, characterized in that A recovery channel (16) is provided between the upper main body frame (1) and the propulsion block (5).

7. The method according to claim 1, characterized in that A hollow groove (8) is provided inside the lower main body frame (2).

8. The method according to claim 1, characterized in that: The material of each component of the auxiliary device is metal or metal alloy.

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