A tension testing device for electrical wires and cables

Abstract

The utility model discloses a kind of tension test equipment applied to electric wire cable, it is related to line test technical field, including test base frame, still include top clamping body, first moving block, locking bolt one, top clamping plate, upper side buffer mechanism and downside protection mechanism, top clamping body is slidably connected in test base frame, first moving block is slidably connected in top clamping body, locking bolt one is passed in the inside of first moving block, the end of locking bolt one passed into first moving block is tightly pressed top clamping body, top clamping plate is installed in the lower surface of first moving block, upper side buffer mechanism is arranged in the side of top clamping body, downside protection mechanism is arranged below upper side buffer mechanism, the utility model is by above-mentioned technical scheme, to solve the problem that one end of cable is thrown to outside in prior art when breaking, the moving direction of the end thrown out is difficult to control and swing range is larger, easy to cause harm to operator.

Description

Technical Field

[0001] This utility model relates to the field of circuit testing technology, and in particular to a tensile testing device for wires and cables. Background Technology

[0002] Tensile testing of wires and cables simulates their performance under different stresses by applying force, thereby assessing their reliability and durability.

[0003] Existing tensile testing equipment fixes the bottom end of the cable to a bottom clamp and the top end of the cable to a movable clamp. The movable clamp is equipped with a tensile testing head, which is connected to the testing equipment to detect the cable stress. The cable is stretched by pulling the movable clamp, and the tensile testing head transmits the cable stress to the testing equipment for reading. However, the contact points between the clamp and the two ends of the cable are prone to breakage during stretching. The broken end moves rapidly in the other direction, which can easily cause danger to nearby operators.

[0004] The tensile testing equipment described above is prone to causing the broken end of the cable to swing outwards. Regardless of whether the break is at the top or bottom of the cable, the swing length after the cable breaks is almost the entire length of the cable. This large swing range can easily cause harm to the operator, or require the operator to stand at least outside this range. Utility Model Content

[0005] The purpose of this invention is to provide a tensile testing device for wires and cables, which solves the problem that when one end of a broken cable is thrown outward, the direction of movement of the thrown end is difficult to control and the swing range is large, which can easily cause harm to the operator.

[0006] To achieve this objective, the present invention adopts the following technical solution: a tensile testing device for wires and cables, comprising a test base frame, and further comprising:

[0007] The top clamp is slidably connected to the test base frame, the first movable block is slidably connected to the top clamp, a locking bolt is threaded through the first movable block, one end of the locking bolt is inserted into the first movable block and abuts against the top clamp, the top clamping plate is installed on the lower surface of the first movable block, the upper buffer mechanism is disposed on the side of the top clamp, and the lower protective mechanism is disposed below the upper buffer mechanism.

[0008] As a preferred embodiment of the tensile testing equipment for wires and cables described in this utility model, in order to facilitate the operation and protection of the device, the upper buffer mechanism includes a connecting piece, a connecting tube, a moving rod, and a second locking bolt. The connecting piece is installed on the outside of the top clamp, the connecting tube is installed on the upper surface of the connecting piece, the moving rod passes through the inside of the connecting tube, the outer surface of the moving rod passes through the inside of the connecting piece, and the second locking bolt is threaded through and connected to the connecting tube. One end of the second locking bolt that passes through the connecting tube can abut against the moving rod.

[0009] In a preferred embodiment of the tensile testing equipment for wires and cables described in this utility model, in order to adjust the position of the auxiliary wheel according to the cable size, a connecting frame is rotatably mounted on the bottom end of the moving rod, and an auxiliary wheel is mounted on the inner side of the connecting frame.

[0010] As a preferred embodiment of the tensile testing equipment for wires and cables described in this utility model, in order to improve the safety of the device, the lower protective mechanism includes a mounting plate, a rotation path guide rod, a buffer spring, and a protective arm. The mounting plate is installed on the lower surface of the connecting frame, the rotation path guide rod is installed on the lower surface of the connecting frame, the buffer spring is installed on the lower surface of the connecting frame, and the protective arm is rotatably connected within the mounting plate.

[0011] In a preferred embodiment of the tensile testing device for wires and cables described in this utility model, in order to prevent the protective arm from flying out after being impacted, the outer surface of the rotation path guide rod penetrates the interior of the protective arm, and the inner end of the buffer spring is installed on the outer side of the protective arm.

[0012] In a preferred embodiment of the tensile testing device for wires and cables described in this utility model, the outer surface of the rotation path guide rod penetrates the interior of the buffer spring in order to better cushion the protective arm.

[0013] In a preferred embodiment of the tensile testing equipment for wires and cables described in this utility model, in order to prevent the cable from protruding outward, a fixing plate is installed on the lower surface of the protective arm, and a protective frame is installed on the outer side of the fixing plate.

[0014] As a preferred embodiment of the tensile testing equipment for wires and cables described in this utility model, in order to better install the bottom clamp, a bottom clamp is provided inside the test base frame, and a locking bolt is passed through the back of the test base frame.

[0015] As a preferred embodiment of the tensile testing equipment for wires and cables described in this utility model, in order to prevent the bottom clamp from loosening, one end of the locking bolt passes through the test base frame and is threaded through the bottom clamp.

[0016] As a preferred embodiment of the tensile testing device for wires and cables described in this utility model, in order to better fix the cable, a second moving block is slidably connected inside the bottom clamp, and a locking bolt four is threadedly connected through the upper surface of the second moving block. One end of the locking bolt four, which passes through the second moving block, can abut against the bottom clamp.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] 1. In this utility model, by manipulating the moving rod to move downward along the connecting pipe, the auxiliary wheel moves downward along the cable. Compared with the direct stretching of the cable in the prior art, this device can limit the cable during the stretching process and reduce the speed at which the cable is thrown outward.

[0019] 2. In this utility model, the protective frame blocks the thrown cable, causing the protective arm to move outward and compress the buffer spring. Compared with the existing technology where the cable is thrown outward, this device can block the thrown cable to the maximum extent and avoid harm to the operator. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] The structures, proportions, sizes, etc., shown in the accompanying drawings of this specification are only for the purpose of assisting those skilled in the art in understanding and reading the content disclosed in the specification, and are not intended to limit the implementation conditions of this utility model. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportions, or adjustments to the size, without affecting the effects and purposes that this utility model can produce, should still fall within the scope of the technical content disclosed in this utility model.

[0022] Figure 1 This is a schematic diagram of the overall structure of a tensile testing device for wires and cables.

[0023] Figure 2This is a schematic diagram of the cooperation structure between the bottom clamp and the second moving block in a tensile testing device for wires and cables.

[0024] Figure 3 This is a schematic diagram of the mating structure of the top clamp and connecting piece in a tensile testing device for wires and cables.

[0025] Figure 4 This is an exploded view of the connecting frame and mounting plate mating structure in a tensile testing device for wires and cables.

[0026] Figure 5 This is a schematic diagram of the overall structure of a tensile testing device for wires and cables from another perspective.

[0027] Figure 6 This is a partial cross-sectional structural diagram of the top clamp, first moving block, top clamping plate, and connecting piece in a tensile testing device for wires and cables.

[0028] Illustration: 1. Test base frame; 2. Top clamp; 3. First moving block; 4. Locking bolt one; 5. Top clamping plate; 6. Connecting piece; 7. Connecting pipe; 8. Moving rod; 9. Locking bolt two; 10. Connecting frame; 11. Auxiliary wheel; 12. Mounting piece; 13. Rotation path guide rod; 14. Buffer spring; 15. Protective arm; 16. Fixing piece; 17. Protective frame; 18. Bottom clamp; 19. Locking bolt three; 20. Second moving block; 21. Locking bolt four; 22. Bottom clamping plate; 23. Push rod motor; 24. Auxiliary frame; 25. Support plate. Detailed Implementation

[0029] To make the utility model's objectives, features, and advantages more apparent and understandable, the technical solutions in the embodiments of the present utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described below are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present utility model.

[0030] In the description of this utility model, it should be understood that the terms "upper," "lower," "top," "bottom," "inner," and "outer," etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. It should be noted that when a component is considered to be "connected" to another component, it can be directly connected to the other component or there may be a component centrally located at the same time.

[0031] The technical solution of this utility model will be further described below with reference to the accompanying drawings and specific embodiments.

[0032] like Figures 1-6 As shown, this utility model embodiment provides a tensile testing device for wires and cables, including a test base frame 1, a top clamp 2, a first moving block 3, a locking bolt 4, a top clamping plate 5, an upper buffer mechanism, and a lower protective mechanism.

[0033] like Figure 3 As shown, the top clamp 2 is slidably connected to the test base frame 1, and the top clamp 2 can slide vertically along the height direction of the test base frame 1. The first moving block 3 is slidably connected to the top clamp 2, as shown. Figure 6 As shown, a clamping groove is provided on the lower side of the top clamp 2. Two first moving blocks 3 are arranged opposite each other. The two first moving blocks 3 can slide closer or further away from each other in the clamping groove. A locking bolt 4 is threaded through the inside of the first moving block 3. The locking bolt 4 is used to lock and limit the sliding position of the first moving block 3 in the clamping groove.

[0034] Specifically, when the two first moving blocks 3 slide closer to each other, the two top clamping plates 5 will move closer to each other, thereby clamping the top of the cable under test. At this time, the locking bolt 4 is screwed from the bottom of the first moving block 3 to the top clamping body 2 to fix the top of the cable. The end of the locking bolt 4 that penetrates into the first moving block 3 abuts against the inner top wall of the clamping groove, thereby locking and limiting the sliding position of the first moving block 3.

[0035] The top clamping plate 5 is installed on the lower surface of the first moving block 3, the upper buffer mechanism is set on the side of the top clamping body 2, and the lower protection mechanism is set below the upper buffer mechanism.

[0036] like Figure 4As shown, the upper buffer mechanism includes a connecting piece 6, a connecting tube 7, a moving rod 8, and a second locking bolt 9. The connecting piece 6 is installed on the outside of the top clamping body 2. Specifically, the top clamping plate 5 is connected to the side of the connecting piece 6 away from the top clamping plate 5. The two sides of the clamping bottom groove are connected to the outside through a sliding groove. The other side of the connecting piece 6 extends out of the sliding groove and can slide inside the sliding groove. The connecting tube 7 is installed on the upper surface of the connecting piece 6. The moving rod 8 passes through the inside of the connecting tube 7 and passes through the connecting piece 6. The second locking bolt 9 is threadedly connected to the connecting tube 7. One end of the second locking bolt 9 that passes through the connecting tube 7 can press against the moving rod 8, thereby locking and limiting the sliding position of the moving rod 8 in the connecting tube 7. A connecting frame 10 is installed at the bottom end of the moving rod 8. An auxiliary wheel 11 is rotatably installed on the inner side of the connecting frame 10. The auxiliary wheel 11 is used to contact the surface of the cable, so that the upper part of the cable... After the cable breaks off and is thrown out, the auxiliary wheel 11 can slow down the downward speed of the cable. It should be noted that the lower surface of the top clamp 2 has a mounting hole for fixing the detection head of the external testing equipment. In addition, the surface material of the auxiliary wheel 11 can be made of rubber to give it good friction. Since the auxiliary wheel 11 moves to the middle of the cable during use, even if the auxiliary wheel 11 is made of ordinary material, it can slow down the cable movement. The two auxiliary wheels 11 can move closer to each other with the top clamping plate 5, so after the auxiliary wheels 11 are in position, they also clamp the cable, thereby reducing the large swing of the cable during its fall. In addition, when the cable falls, it will drive the auxiliary wheel 11 to rotate. The rotation damping of the auxiliary wheel 11 needs to be large, for example, by using a damping bearing, so that even when the auxiliary wheel 11 rotates, it will be at a slow rotation speed, which will have a more efficient slowing effect on the cable clamping.

[0037] Specifically, when the manipulating lever 8 moves downward along the height direction of the connecting pipe 7, the lever 8 moves downward, causing the connecting frame 10 to move downward. The connecting frame 10 moves downward, causing the auxiliary wheel 11 to move downward. Thus, the clamping and buffering position of the two auxiliary wheels 11 on the length of the cable can be adjusted according to the length of the cable.

[0038] like Figure 4As shown, the lower protective mechanism includes a mounting plate 12, a rotation path guide rod 13, a buffer spring 14, and a protective arm 15. The mounting plate 12 is installed on the lower surface of the connecting frame 10, the rotation path guide rod 13 is installed on the lower surface of the connecting frame 10, the buffer spring 14 is installed on the lower surface of the connecting frame 10, and the protective arm 15 is rotatably connected inside the mounting plate 12. The rotation path guide rod 13 passes through the protective arm 15. The initial state of the protective arm 15 is tilted to facilitate the protective frame 17 to block the thrown cable. The inner end of the buffer spring 14 is installed on the outer side of the protective arm 15, and the outer surface of the rotation path guide rod 13 passes through the interior of the buffer spring 14. A fixing plate 16 is installed on the lower surface of the protective arm 15, and a protective frame 17 is installed on the outer side of the fixing plate 16. Two protective frames 17 are symmetrically installed on each fixing plate 16. The protective frames 17 are L-shaped, and when the four protective frames 17 are closed, they can form a frame, thereby framing the swinging part of the cable and reducing the swinging range of the cable.

[0039] It should be noted that the design of features such as the mounting plate 12, the rotation path guide rod 13, and the buffer spring 14 is to further buffer the impact received by the protective frame 17. When the initial downward swing of the cable is strong, although the four protective frames 17 can enclose and frame the swinging part of the cable, the impact force borne by the protective frame 17 may be relatively large. Therefore, when the impact force borne by the protective frame 17 is relatively large, the protective frame 17 can rotate outward, which also drives the protective arm 15 to move slightly outward. The protective arm 15 moves outward along the rotation path guide rod 13 to compress the buffer spring 14, thereby buffering the impact received by the protective frame 17 through the buffer spring 14. Since the protective frame 17 is a directly stressed component, the buffer spring 14 is not a direct force-bearing component. As the component receiving force, the spring movement of the buffer spring 14 is actually quite weak, and it will not repeatedly bounce continuously (a spring with suitable elasticity needs to be selected; if the selected spring has too little elastic damping, it will bounce repeatedly under slight force, which is not desired in this application, as this would also increase the possibility of the cable escaping from the protective frame 17). In this application, the buffer spring 14 needs to be a spring with greater damping, so that the protective frame 17 can be closed most of the time, and can be elastically buffered within a small range when subjected to impact. At the same time, the sliding of the protective arm 15 on the rotation path guide rod 13 is also a kind of damping, so that the buffer spring 14 can stabilize relatively quickly in addition to the bouncing buffer).

[0040] In addition, in order to ensure that the protective arm 15 is smoothly guided by the rotation path guide rod 13, the center of the rotation path guide rod 13 needs to be in the same position as the center of rotation of the protective arm 15 on the mounting plate 12, so as to avoid the protective arm 15 being jammed by the rotation path guide rod 13 during rotation.

[0041] like Figure 2As shown, a bottom clamp 18 is fixedly installed on the lower side of the test base frame 1. A locking bolt 3 19 passes through the back of the test base frame 1. One end of the locking bolt 3 19 passes through the test base frame 1 and is threaded into the bottom clamp 18 (the bottom clamp 18 can also be directly fixedly connected to the lower side of the test base frame 1). A second moving block 20 is slidably connected inside the bottom clamp 18. A clamping top groove is opened on the upper side of the bottom clamp 18. Two second moving blocks 20 are arranged opposite each other. The two second moving blocks 20 can slide closer or further apart relative to each other in the clamping top groove. A locking bolt 4 21 is threadedly connected through the upper surface of the second moving block 20. One end of the locking bolt 4 21 that passes into the second moving block 20 can press against the bottom clamp 18. When the two second moving blocks 20 slide closer relative to each other, they can drive the two bottom clamping plates 22 to slide closer relative to each other, thereby clamping and fixing the lower side of the cable.

[0042] In this embodiment, as Figure 1 As shown, a push rod motor 23 is installed on the back of the test base frame 1, and an auxiliary frame 24 is installed at the output end of the push rod motor 23. The auxiliary frame 24 is slidably connected inside the test base frame 1, and the front of the auxiliary frame 24 is installed on the back of the top clamp 2. A support plate 25 is installed on the lower surface of the test base frame 1.

[0043] Working principle: The external tensile force detection head is fixed to the lower surface of the top clamp 2 through the mounting hole. The bottom of the cable is placed above the bottom clamp 18. The two second moving blocks 20 are manipulated to drive the two bottom clamping plates 22 to slide closer to each other, clamping and fixing the bottom of the cable. Then, the locking bolts 21 are manipulated to pass through the second moving blocks 20 and press against the bottom clamp 18 to lock the sliding position of the second moving blocks 20.

[0044] Move the top of the cable below the top clamp 2, manipulate the two first moving blocks 3 to drive the two top clamping plates 5 to slide closer to each other, clamp and fix the top of the cable, and then manipulate the locking bolt 4 to pass through the first moving block 3 and press against the top clamp 2 to lock the sliding position of the first moving block 3. During this process, the two top clamping plates 5 move inward relative to each other, which will drive the two connecting plates 6 to move inward relative to each other. The connecting plates 6 indirectly drive the two auxiliary wheels 11 to move closer to each other through the moving rod 8 and the connecting frame 10, so that the two auxiliary wheels 11 contact the cable and clamp the cable.

[0045] After the clamping and fixing of the cable under test is completed, before the tensile test, the locking bolt 29 needs to be loosened first. At this time, the moving rod 8 can be manipulated to move along the connecting pipe 7. The moving rod 8 drives the connecting frame 10 to move downward, so that the auxiliary wheel 11 rolls along the cable. At this time, the cable has not been stretched yet. Until the auxiliary wheel 11 clamps the cable in a suitable position, the better position is to clamp it in the middle of the cable. After adjustment, the locking bolt 29 is manipulated to continue to press against the moving rod 8. At the same time, the connecting frame 10 moves downward, which drives the mounting plate 12 to move downward. The mounting plate 12 moves downward, which drives the protective arm 15 to move downward. The protective arm 15 moves downward, which drives the fixing plate 16 to move downward. The fixing plate 16 moves downward, which drives the protective frame 17 to move downward, so that the protective frame 17 moves to the lower middle part of the cable. The four protective frames 17 frame the lower middle part of the cable.

[0046] During the tensile test, the push rod motor 23 is started. The output end of the push rod motor 23 moves upward, causing the auxiliary frame 24 to move upward. The auxiliary frame 24 moves upward, causing the top clamp 2 to move upward. The bottom of the cable remains fixed, while the upper side is gradually stretched upward. At the same time, the tensile testing head analyzes the force on the cable during the stretching process and transmits it to the equipment connected to the tensile testing head.

[0047] During a tensile test, if the cable breaks, there are two possible breakage scenarios:

[0048] First: The upper side of the cable breaks. In this case, the cable will fall due to gravity because it loses its grip. When the cable falls, it will cause the auxiliary wheel 11 to rotate. However, since the cable falls down from the two auxiliary wheels 11, when the auxiliary wheels 11 are in the middle of the cable, in the initial stage of the cable breakage, the length of the cable above the height of the auxiliary wheels 11 is at most only half of the total length of the cable. As the cable falls, the length of the cable above the auxiliary wheels 11 will become shorter and shorter, and the swing length and swing range of the cable will also become smaller and smaller. During this process, the four protective frames 17 will also hold the cable until the cable completely falls from the two auxiliary wheels 11 and the fall ends after passing through the four protective frames 17.

[0049] Second: The lower side of the cable breaks. In this case, the top of the cable is still clamped and the cable will not fall down, but the lower side of the cable will swing. In this case, since the auxiliary wheel 11 is located in the middle of the cable, the length of the cable below the height of the auxiliary wheel 11 when the cable breaks is at most only half of the total length of the cable. Moreover, this half of the cable is surrounded and framed by the four protective frames 17. After multiple restrictions, the swing of the cable will be very small.

[0050] Finally, it should be noted that when the tested cable breaks, the swinging motion cannot be completely stopped; the key factor is the size of the swinging range. In the existing tensile testing equipment mentioned in the background of this application, regardless of whether the break occurs at the top or bottom of the cable, the swinging length after the cable breaks is almost the entire length of the cable. That is, assuming the tested cable is 5 meters long, the maximum swinging length after breakage is also 5 meters. Such a large swinging range can easily cause harm to the operator, or require the operator to stand at least outside this range.

[0051] With the design of this application for the two directions, when the tested cable breaks, the initial swing length is only half the length of the tested cable, and the swing range will become smaller and slower, thereby minimizing the chance of the cable swinging causing harm to the operator. The operator can also stand in a position relatively close to this application, which is more conducive to the operator to carry out the test operation.

[0052] The above-described embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this utility model.

Claims

1. A tension testing apparatus applied to an electric wire cable, comprising a test base frame (1), characterized in that, Also includes: Top clamp (2), which is slidably connected to the test base frame (1); The first movable block (3) is slidably connected to the top clamp (2). A locking bolt (4) is threaded through the first movable block (3). One end of the locking bolt (4) is inserted into the first movable block (3) and abuts against the top clamp (2). A top clamping plate (5) is mounted on the lower surface of the first moving block (3); An upper buffer mechanism is provided on the side of the top clamp (2); A lower protective mechanism is provided below the upper buffer mechanism.

2. A tension testing apparatus for electrical cables as claimed in claim 1 wherein: The upper buffer mechanism includes: Connecting piece (6), the connecting piece (6) is installed on the outside of the top clamp (2); A connecting pipe (7) is installed on the upper surface of the connecting piece (6). A moving rod (8) passes through the inside of the connecting pipe (7), and the outer surface of the moving rod (8) passes through the inside of the connecting piece (6). Locking bolt two (9) is threaded through and connected to the connecting pipe (7). One end of the locking bolt two (9) that goes into the connecting pipe (7) can abut against the moving rod (8).

3. A tension testing apparatus for electrical cables as claimed in claim 2 wherein: A connecting frame (10) is installed at the bottom end of the moving rod (8), and an auxiliary wheel (11) is rotatably installed on the inner side of the connecting frame (10).

4. A tension testing apparatus for electrical cables as claimed in claim 3 wherein: The lower protective mechanism includes: Mounting plate (12), the mounting plate (12) is mounted on the lower surface of the connecting frame (10); Rotation path guide rod (13), the rotation path guide rod (13) is installed on the lower surface of the connecting frame (10); A buffer spring (14) is mounted on the lower surface of the connecting frame (10); Protective arm (15), which is rotatably connected within the mounting plate (12).

5. A tension testing apparatus for electrical cables as claimed in claim 4 wherein: The outer surface of the rotation path guide rod (13) extends through the interior of the protective arm (15), and the inner end of the buffer spring (14) is mounted on the outer side of the protective arm (15).

6. The tensile testing equipment for wires and cables as described in claim 5, characterized in that: The outer surface of the rotation path guide rod (13) extends through the interior of the buffer spring (14).

7. The tensile testing equipment for wires and cables as described in claim 4, characterized in that: A fixing plate (16) is installed on the lower surface of the protective arm (15), and a protective frame (17) is installed on the outer side of the fixing plate (16).

8. The tensile testing equipment for wires and cables as described in claim 1, characterized in that: The test base frame (1) has a bottom clamp (18) inside, and a locking bolt (19) runs through the back of the test base frame (1).

9. The tensile testing equipment for wires and cables as described in claim 8, characterized in that: The locking bolt three (19) is threaded through one end of the test base frame (1) and inserted into the bottom clamp (18).

10. The tensile testing equipment for wires and cables as described in claim 9, characterized in that: The bottom clamp (18) is slidably connected to a second moving block (20), and a locking bolt four (21) is threadedly connected to the upper surface of the second moving block (20). One end of the locking bolt four (21) inserted into the second moving block (20) can abut against the bottom clamp (18).

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