Electrical circuit detector with convenient clamping structure

Abstract

The utility model relates to electrical circuit detection equipment technical field discloses electrical circuit detector convenient to clamping structure, including display, the rear side of display is provided with telescopic mechanism, the top of telescopic mechanism is provided with rotating mechanism, the top of rotating mechanism is provided with shell no. 2, telescopic mechanism includes a plurality of lower cylinders, the inner wall sliding connection of a plurality of lower cylinders has middle cylinder, the inner wall sliding connection of a plurality of middle cylinders has upper cylinder, the rear side sliding connection of a plurality of lower cylinders outer wall has button. In the utility model, through the inclined plane transmission of rear sliding block and front sliding block driven by button, cooperate the tensile transmission of rope and the telescoping of support bar no. 1, realize the contraction clamping of clamping jaw in shell no. 1, avoid the unstable clamping caused by hand fatigue when working at height, ensure that detection probe and line stable contact, improve the operation difficulty and detection accuracy when detecting line at height.

Description

Technical Field

[0001] This utility model relates to the field of electrical circuit testing equipment technology, and in particular to an electrical circuit testing instrument with a convenient clamping structure. Background Technology

[0002] Electrical circuit inspection is a crucial step in ensuring the normal operation of power systems and communication networks. By testing the continuity, insulation performance, voltage, and current of lines, faults and aging issues can be detected in a timely manner, enabling targeted repairs and maintenance. Its applications are wide-ranging, covering various locations where electrical wiring needs to be laid. Traditional electrical circuit testers with easy-to-grip structures mainly consist of a test host, a test probe, a clamping component, and connecting wires. In use, the operator holds the test host and fixes the test probe to the electrical circuit to be tested using the clamping component. The test host then reads and displays the test data. However, these traditional testers have obvious drawbacks. The clamping force of the clamping component cannot be precisely controlled, which can result in poor contact due to excessively loose clamping or damage to the circuit due to excessively tight clamping. Furthermore, the position of the clamping component is relatively fixed and cannot be flexibly adjusted according to the position of the circuit. To address some of the aforementioned issues, existing technologies have improved the clamping structure by employing adjustable clamping components. The clamping distance can be adjusted via a knob to accommodate wires of different diameters. However, in actual testing, inconvenience remains when dealing with electrical lines at heights. Workers need to use ladders to operate from above, and during this process, the handheld testing instrument wobbles, preventing the clamping components from accurately aligning and securing to the high-altitude lines. Even when the clamping components are successfully secured, the limited operating space at height makes it difficult to maintain a stable grip on the testing unit, affecting the reading and recording of test data. This is primarily because the existing improved testing instruments are not specifically designed for overall length and ease of operation, failing to meet the needs of testing lines at heights. Utility Model Content

[0003] To overcome the above shortcomings, this utility model provides an electrical circuit tester with a convenient clamping structure, aiming to improve the problem of inconvenience in testing high-altitude circuits in the prior art.

[0004] To achieve the above objectives, the present invention adopts the following technical solution: an electrical circuit tester with a clamping structure, including a display, a telescopic mechanism provided on the rear side of the display, a rotating mechanism provided on the top of the telescopic mechanism, and a housing second provided on the top of the rotating mechanism; The telescopic mechanism includes multiple lower cylinders, each disposed on the rear side of a corresponding display. A middle cylinder is slidably connected to the inner wall of each lower cylinder, and an upper cylinder is slidably connected to the inner wall of each middle cylinder. Buttons are slidably connected to the rear side of the outer wall of each lower cylinder. Rear sliders are fixedly connected to the front side of each button, and front sliders are slidably connected to the front side of each rear slider. Ropes are fixedly connected to the top of each front slider, and winding spools are slidably connected to the bottom of each rope. Each winding spool is rotatably connected to the inner wall of a corresponding lower cylinder. Two support rods are fixedly connected to the top of each rope, and each support rod is rotatably connected to a corresponding outer casing. A clamping assembly is provided at the top of each support rod.

[0005] As a further description of the above technical solution: The rotating mechanism includes multiple support rings. The multiple support rings at the bottom are fixedly connected to the corresponding upper cylinders, and the multiple support rings at the top are rotatably connected to the corresponding upper cylinders. Multiple springs are fixedly connected between adjacent support rings. Multiple support rods are fixedly connected to the top of each of the multiple springs at the top. Multiple toothed blocks are fixedly connected to the front and rear sides of the multiple support rings at the top. Screws are threadedly connected to the front and rear sides of the top of the multiple upper cylinders. A rack is fixedly connected to an adjacent side of each screw. The racks engage with the corresponding toothed blocks.

[0006] As a further description of the above technical solution: The clamping assembly includes multiple grippers, each gripper being fixedly connected to the top of a corresponding front slider. The outer walls of the multiple grippers are slidably connected to the same outer shell. A spring is fixedly connected to the outer walls of the multiple grippers on opposite sides, and the springs are fixedly connected to the inner walls of the corresponding outer shells.

[0007] As a further description of the above technical solution: Each of the lower cylinders has a sliding groove on its inner rear side, and each of the front sliders has a limit slider fixedly connected to its front side. The sliding grooves are slidably connected to the corresponding limit sliders.

[0008] As a further description of the above technical solution: Multiple winding spools are fixedly connected to the right side of the display, and a handle is fixedly connected to the top of the display.

[0009] As a further description of the above technical solution: The bottom of the display is fixedly connected to multiple connectors, and the bottom of the multiple connectors is rotatably connected to the same support frame.

[0010] As a further description of the above technical solution: The rear side of the display is fixedly connected to multiple fixing brackets. The upper fixing brackets are respectively engaged with the corresponding middle cylinders, and the lower fixing brackets are respectively engaged with the corresponding lower cylinders.

[0011] As a further description of the above technical solution: Multiple friction grooves are provided on the bottom of the outer wall of each of the multiple lower cylinders, and the spacing between the multiple friction grooves is equal. The tops of the multiple lower cylinders and the multiple middle cylinders are all threaded with screws.

[0012] This utility model has the following beneficial effects: 1. In this utility model, the overall length can be flexibly adjusted and securely locked by the nested sliding cooperation of the lower, middle and upper cylinders, combined with the fixing effect of the screw two. The inclined plane transmission of the rear and front sliders is driven by the button, and the tension of the rope and the extension and retraction of the support rod one are combined to realize the contraction and clamping of the claws in the outer shell one. Then, with the elastic reset of the spring one, a complete clamping control closed loop is formed, which replaces the traditional manual gripping method, avoids the instability of clamping caused by hand fatigue when working at height, ensures stable contact between the detection probe and the line, and improves the operation difficulty and detection accuracy when detecting lines at height.

[0013] 2. In this utility model, the rotational connection between the support ring and the upper cylinder in the rotating mechanism, combined with the angle transmission of the three pairs of clamping components of the support rod, the engagement and fixation of the rack and tooth block driven by the screw one, and the reset function of the spring two, realizes the flexible adjustment and stable locking of the clamping angle. This structure solves the problem that the fixed angle of the equipment in the prior art cannot adapt to different routing lines, enabling the detector to quickly align with lines of various angles, greatly improving the adaptability to complex wiring environments, and reducing detection omissions or errors caused by unsuitable angles. Attached Figure Description

[0014] Figure 1 This is a perspective view of the electrical circuit tester with a convenient clamping structure proposed in this utility model; Figure 2 This is a front view of the electrical circuit tester with a convenient clamping structure proposed in this utility model; Figure 3 This is a schematic diagram of the telescopic mechanism of the electrical circuit tester with a convenient clamping structure proposed in this utility model; Figure 4 This is a cross-sectional view of the lower cylinder of the electrical circuit tester with a convenient clamping structure proposed in this utility model; Figure 5 This is a structural exploded view of the clamping assembly of the electrical circuit tester with a convenient clamping structure proposed in this utility model; Figure 6 for Figure 5 Enlarged view of point A in the image; Figure 7 This is a schematic diagram of the electrical circuit tester mounting bracket with a convenient clamping structure proposed in this utility model.

[0015] Legend: 1. Display; 2. Telescopic mechanism; 201. Lower cylinder; 202. Middle cylinder; 203. Upper cylinder; 204. Button; 205. Rear slider; 206. Front slider; 207. Rope; 208. Winding spool one; 209. Support rod one; 210. Clamping assembly; 2101. Gripper; 2102. Outer shell one; 2103. Spring one; 3. Rotating mechanism; 301. Support ring; 302. Spring two; 303. Support rod three; 304. Tooth block; 305. Screw one; 306. Rack; 4. Outer shell two; 5. Slide groove; 6. Limit slider; 7. Winding spool two; 8. Handle; 9. Connecting seat; 10. Support frame; 11. Fixing frame; 12. Friction groove; 13. Screw two. Detailed Implementation

[0016] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments 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 of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0017] Reference Figure 3 , Figure 4 and Figure 5This utility model provides an embodiment of an electrical circuit detector with a convenient clamping structure, including a display 1 that displays data related to the detected electrical circuits. A telescopic mechanism 2 is provided on the rear side of the display 1 to adjust the overall length of the detector to accommodate different heights. A rotating mechanism 3 is provided on the top of the telescopic mechanism 2 to adjust the angle of the clamping assembly 210 to accommodate circuits with different orientations. A housing 4 is provided on the top of the rotating mechanism 3 to protect the internal parts. The telescopic mechanism 2 includes multiple lower cylinders 201 as basic support components. The multiple lower cylinders 201 are respectively configured... On the rear side of the corresponding display 1, a middle cylinder 202 is slidably connected to the inner wall of multiple lower cylinders 201, allowing them to slide within the lower cylinders 201 for initial length adjustment. An upper cylinder 203 is slidably connected to the inner wall of multiple middle cylinders 202, allowing them to slide within the middle cylinders 202 for further length adjustment of the telescopic mechanism 2. A button 204 is slidably connected to the rear side of the outer wall of multiple lower cylinders 201 to control the clamping and releasing of the clamping assembly 210. A rear slider 205 is fixedly connected to the front side of each button 204 to transmit the force of the button 204. A front slider 206 is slidably connected to the front side of each rear slider 205 to transmit the force of the button 204. The movement is caused by the push of block 205. Ropes 207 are fixedly connected to the tops of multiple front sliders 206, transmitting the tension of the front sliders 206. Winding drums 208 are slidably connected to the bottoms of multiple ropes 207, storing the ropes 207 so that the length of the ropes 207 can be adjusted simultaneously when adjusting the length of the outer drum. Multiple winding drums 208 are rotatably connected to the inner walls of their respective lower drums 201. Two support rods 209 are fixedly connected to the tops of multiple ropes 207, driving the gripper 2101 to move. Multiple support rods 209 are rotatably connected to their respective outer shells 4. The tops of the support rods 209... The part is provided with a clamping assembly 210, which directly clamps the electrical circuit. The clamping assembly 210 includes multiple jaws 2101, which clamp or release the circuit. The multiple jaws 2101 are fixedly connected to the top of the corresponding front slider 206. The outer walls of the multiple jaws 2101 are slidably connected to the same outer shell 2102, which limits the movement trajectory of the jaws 2101 and provides protection. The outer walls of the multiple jaws 2101 are fixedly connected to springs 2103 on the side away from each other. When the button 204 is released, the jaws 2101 are driven to reset. The multiple springs 2103 are fixedly connected to the inner walls of the corresponding outer shells 2102. Specifically, the upper cylinder 203 is pulled to slide along the inner wall of the middle cylinder 202, and the middle cylinder 202 simultaneously extends and retracts along the inner wall of the lower cylinder 201 until the clamping assembly 210 reaches the detection position. The relative positions of the three cylinders are fixed using screw 13, solving the problem of manual climbing or the inability to reach the probe by hand. During detection, the button 204 on the outer wall of the lower cylinder 201 is pressed, causing the rear slider 205 to slide forward. Its inclined surface pushes the front slider 206 upward, and the front slider 206 pulls the rope 207. The rope 207 is guided by the first winding cylinder 208 and the second winding cylinder 7, causing the two side support rods 209 to retract, thereby... The gripper 2101 closes within the outer casing 2102 to clamp and secure the high-altitude wiring, preventing poor contact caused by shaking during manual lifting. The detection data is transmitted to the display 1 in real time, eliminating the need for staff to get close to check. When the button 204 is released, the spring 2103 pushes the gripper 2101 back to its original position. The rope 207 pulls the front slider 206 and the rear slider 205 in the opposite direction, causing the button 204 to spring back, achieving rapid release. Combined with the length adjustment of the telescopic mechanism 2, it comprehensively covers the wiring detection needs at different high-altitude locations, solving the problem of inconvenience for high-altitude wiring detection in existing equipment.

[0018] Reference Figure 1 , Figure 2 and Figure 6 The rotating mechanism 3 includes multiple support rings 301, which are the core rotating components of the rotating mechanism 3. The multiple support rings 301 at the bottom are fixedly connected to the corresponding upper cylinders 203, and the multiple support rings 301 at the top are rotatably connected to the corresponding upper cylinders 203. Multiple springs 302 are fixedly connected between adjacent support rings 301, providing a reset force for the support rings 301 after rotation. Multiple support rods 303 are fixedly connected to the top of each of the multiple springs 302 at the top, connecting the springs 302 to the clamping assembly 210. It transmits power. Multiple toothed blocks 304 are fixedly connected to the front and rear sides of the multiple support rings 301 at the top. They can be fixed at the angle of the support rings 301 by cooperating with the rack 306. Screws 305 are threadedly connected to the front and rear sides of the top of the multiple upper cylinders 203. They push the rack 306 to move so as to engage or disengage with the toothed blocks 304. A rack 306 is fixedly connected to the adjacent side of the multiple screws 305. The rotation of the support rings 301 is restricted by engaging with the toothed blocks 304. The multiple racks 306 engage with the corresponding toothed blocks 304 respectively. Specifically, when the detection angle needs to be adjusted, first loosen the screws 305 on the front and rear sides of the top of the upper cylinder 203. Screws 305 drive the rack 306 to move away from the toothed block 304, causing the rack 306 to disengage from the toothed block 304 on the front and rear sides of the top support ring 301, thus releasing the fixation on the support ring 301. Then, rotate the top support ring 301. The top support ring 301 drives the connected support rod 303 and clamping assembly 210 to rotate synchronously. At this time, the springs 302 between adjacent support rings 301 will deform due to the rotation of the support ring 301, storing elasticity for subsequent reset. After rotating to the position of the top support ring 301, the springs 302 will be adjusted accordingly. After the line direction is matched with the angle, tighten screw 305. Screw 305 pushes rack 306 to re-engage with tooth block 304. Through the meshing action of rack 306 and tooth block 304, support ring 301 is fixed at the current angle, ensuring that clamping assembly 210 is stably aligned with the line. After the test is completed, loosen screw 305 again. Spring 302 drives support ring 301 to rotate in the opposite direction under the action of elasticity, so that the entire rotating mechanism 3 returns to the initial position for the next test operation. This solves the problem that the existing equipment has a fixed angle and is not suitable for lines with different directions at height, and improves the flexibility and applicability of the test.

[0019] Reference Figure 1 , Figure 2 and Figure 4 Multiple lower cylinders 201 have grooves 5 on the rear side of their inner walls to provide sliding tracks for the limiting sliders 6. Multiple front sliders 206 are fixedly connected to the front side of each limiting slider 6 to restrict the movement direction of the front sliders 206. Multiple grooves 5 are slidably connected to the corresponding limiting sliders 6. Multiple winding cylinders 7 are fixedly connected to the right side of the display 1 to change the direction of the rope 207 and reduce friction. A handle 8 is fixedly connected to the top of the display 1 to facilitate the carrying and moving of the detector by the staff. Multiple connecting seats 9 are fixedly connected to the bottom of the display 1 to connect the display 1 to the support frame 10. The bottom of the multiple connecting seats 9 is rotatably connected to the same support frame 10 to support the display 1 and make it stable. Specifically, when the front slider 206 moves, the front limiting slider 6 slides along the groove 5 on the rear side of the inner wall of the lower cylinder 201 to limit the offset of the front slider 206 and ensure transmission stability. The winding cylinder 7 is used to store the connecting wire of the entire gripper 2101 device. The handle 8 on the top of the handheld display 1 facilitates the movement of the device. When no testing is required, the support frame 10 at the bottom of the connecting seat 9 is rotated to support the display 1, avoiding direct placement and wear, and improving the convenience of operation and the safety of the equipment.

[0020] Reference Figure 1 , Figure 3 and Figure 7Multiple mounting brackets 11 are fixedly connected to the rear side of the display 1 to enhance the connection stability between the middle cylinder 202 and the lower cylinder 201. The upper mounting brackets 11 are respectively engaged with the corresponding middle cylinders 202, and the lower mounting brackets 11 are respectively engaged with the corresponding lower cylinders 201. Multiple friction grooves 12 are provided on the bottom of the outer wall of the lower cylinders 201 to increase the friction between the hand and the lower cylinders 201. The spacing of the multiple friction grooves 12 is equal. The top of the lower cylinders 201 and the middle cylinders 202 are threadedly connected with screws 13 to fix the relative position of the lower cylinders 201 and the middle cylinders 202. Specifically, the fixing bracket 11 engages with the lower sleeve to enhance the stability of the telescopic mechanism 2. The bottom of the lower sleeve 201 is held by hand, and the friction groove 12 increases friction to prevent slippage. After adjusting the lengths of the lower sleeve 201 and the middle sleeve 202, the top screw 2 13 is tightened to secure it, ensuring that it does not shake during testing and improving operational reliability.

[0021] Working Principle: When clamping and testing cables at height is required, the operator can first flexibly adjust the relative distance between the lower cylinder 201, middle cylinder 202, and upper cylinder 203 according to the actual working height. After adjusting to the appropriate length, tighten screw 13 to form a stable fixed relationship between the lower cylinder 201, middle cylinder 202, and upper cylinder 203. Press the button 204 located at the bottom of the lower cylinder 201. The button 204 will move along its axis in the pressing direction, and simultaneously drive the connected rear slider 205 to move in the same direction. The contact surface between the rear slider 205 and the front slider 206 adopts a sloped structure design. The sloped surface of the rear slider 205 and the sloped surface of the front slider 206 fit together. When the rear slider 205 is pushed forward, the interaction force between the sloped surfaces will drive the front slider 206 to move downward in the vertical direction. The downward movement of the front slider 206 will pull the connected rope 207 downward together. The end away from the front slider 206 is connected to the support rod 209, which in turn drives the support rod 209 to move down and retract. The retraction of the support rod 209 is transmitted to the gripper 2101, causing the gripper 2101 to retract synchronously within the outer shell 2102, thereby achieving the clamping action on the high-level line, ensuring stable contact between the detection probe and the line, and ensuring the smooth progress of the detection work. When it is necessary to cancel the clamping state, the button 204 is released. At this time, the spring 2103 set inside the outer shell 2102 will extend under its own elastic force, pushing the gripper 2101 back to the initial position. The reset of the gripper 2101 will drive the support rod 209 to extend upward, which in turn pulls the front slider 206 upward through the rope 207. The upward movement of the front slider 206 will cause the rear slider 205 to return to its original position under the reaction force of the inclined plane, and finally the button 204 will also return to the initial state, waiting for the next operation. When clamping lines at different angles is required, the operator can rotate the upper support ring 301. The support ring 301 can rotate flexibly around its axis of rotation until it is adjusted to an angle suitable for the line to be tested. During the rotation of the support ring 301, it will drive the support rod 303 fixedly connected to it to rotate together. The support rod 303 will then drive the entire clamping assembly 210 to rotate synchronously, so that the gripper 2101 can be aligned with the line at different angles. After adjusting to the appropriate angle, tighten the screw 305. The screw 305 will move along its axis towards the support ring 301, and drive the rack 306 connected to it to move synchronously, so that the rack 306 is fixed to the support ring 301. The toothed block 304 on the rotating shaft is tightly engaged. The toothed engagement between the rack 306 and the toothed block 304 achieves a stable fixation of the rotating mechanism 3, preventing the clamping assembly 210 from shifting due to external force during the testing process. When the testing is completed and the rotating mechanism 3 needs to be reset, the screw 305 is loosened. The screw 305 will drive the rack 306 to move away from the toothed block 304, causing the rack 306 to disengage from the toothed block 304. At this time, the spring 302 sleeved on the rotating shaft of the support ring 301 will return to its original shape under its own elasticity, pushing the support ring 301 to rotate in the opposite direction around the rotating shaft until it returns to the initial position, thus completing the reset operation of the entire rotating mechanism 3.

[0022] Finally, it should be noted that the above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Although the present utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. An electrical circuit tester with a clamping structure, including a display (1), characterized in that: The display (1) is provided with a telescopic mechanism (2) on the rear side, and a rotating mechanism (3) is provided on the top of the telescopic mechanism (2). The rotating mechanism (3) is provided with a second outer shell (4) on the top of the outer shell. The telescopic mechanism (2) includes multiple lower cylinders (201), each of which is respectively disposed on the rear side of the corresponding display (1). A middle cylinder (202) is slidably connected to the inner wall of each lower cylinder (201), and an upper cylinder (203) is slidably connected to the inner wall of each middle cylinder (202). A button (204) is slidably connected to the rear side of the outer wall of each lower cylinder (201). A rear slider (205) is fixedly connected to the front side of each button (204), and a front slider (205) is slidably connected to the front side of each rear slider (205). 06), the top of each of the multiple front sliders (206) is fixedly connected to a rope (207), the bottom of each of the multiple ropes (207) is slidably connected to a winding drum (208), the multiple winding drums (208) are rotatably connected to the inner wall of the corresponding lower drum (201), the top of each of the multiple ropes (207) is fixedly connected to two support rods (209), the multiple support rods (209) are rotatably connected to the corresponding outer shell (4), and the top of the support rods (209) is provided with a clamping assembly (210).

2. The electrical circuit tester with a clamping structure according to claim 1, characterized in that: The rotating mechanism (3) includes multiple support rings (301). The multiple support rings (301) at the bottom are fixedly connected to the corresponding upper cylinder (203). The multiple support rings (301) at the top are rotatably connected to the corresponding upper cylinder (203). Multiple springs (302) are fixedly connected between adjacent support rings (301). Multiple support rods (303) are fixedly connected to the top of the multiple springs (302) at the top. Multiple toothed blocks (304) are fixedly connected to the front and rear sides of the multiple support rings (301) at the top. Screws (305) are threadedly connected to the front and rear sides of the top of the multiple upper cylinders (203). A rack (306) is fixedly connected to the adjacent side of the multiple screws (305). The multiple racks (306) are engaged with the corresponding toothed blocks (304).

3. The electrical circuit tester with a clamping structure according to claim 1, characterized in that: The clamping assembly (210) includes a plurality of grippers (2101), each gripper (2101) being fixedly connected to the top of the corresponding front slider (206). The outer walls of the plurality of grippers (2101) are slidably connected to the same outer shell (2102). A spring (2103) is fixedly connected to the outer walls of the plurality of grippers (2101) on the side away from each other. The springs (2103) are fixedly connected to the inner walls of the corresponding outer shells (2102).

4. The electrical circuit tester with a clamping structure according to claim 1, characterized in that: Each of the lower cylinders (201) has a sliding groove (5) on the rear side of its inner wall, and each of the front sliders (206) has a limiting slider (6) fixedly connected to its front side. Each of the sliding grooves (5) is slidably connected to the corresponding limiting slider (6).

5. The electrical circuit tester with a clamping structure according to claim 1, characterized in that: Multiple winding spools (7) are fixedly connected to the right side of the display (1), and a handle (8) is fixedly connected to the top of the display (1).

6. The electrical circuit tester with a clamping structure according to claim 1, characterized in that: The bottom of the display (1) is fixedly connected to a plurality of connecting seats (9), and the bottom of the plurality of connecting seats (9) is rotatably connected to the same support frame (10).

7. The electrical circuit tester with a clamping structure according to claim 1, characterized in that: The rear side of the display (1) is fixedly connected with a plurality of fixing brackets (11). The plurality of fixing brackets (11) on the upper side are respectively engaged with the plurality of middle cylinders (202), and the plurality of fixing brackets (11) on the lower side are respectively engaged with the plurality of lower cylinders (201).

8. The electrical circuit tester with a clamping structure according to claim 1, characterized in that: Multiple friction grooves (12) are provided on the bottom of the outer wall of the multiple lower cylinders (201), and the spacing of the multiple friction grooves (12) is equal. The top of the multiple lower cylinders (201) and the multiple middle cylinders (202) are all threadedly connected with screws (13).

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