Anti-loose clamping type cable loop resistance on-line detector

Abstract

This invention relates to the field of resistance testing technology, specifically to an online resistance testing instrument for cable loops with anti-loosening clamping mechanism. The instrument includes a main body with a first and second clamp on its rear side. Both clamps are semi-circular and connected by vertically installed pins. They are used to fit onto the outer wall of a utility pole. Two symmetrically arranged springs are located in the mounting groove, with a wedge-shaped block on the side of each spring closest to it. This invention achieves continuous constant force pre-tightening through a wedge-shaped clamping structure combined with a unidirectional ratchet assembly, solving the problem of pre-tightening force creep loss in traditional threaded connections under long-term wind load vibration. Combined with the spontaneous temperature response of the shape memory metal deformation part, it can automatically convert environmental temperature difference energy into pre-tightening compensation force, achieving online automatic compensation of pre-tightening force without additional energy, thus avoiding loosening caused by material relaxation or thermal expansion and contraction.

Description

Technical Field

[0001] This invention relates to the field of resistance testing technology, specifically to an online resistance testing instrument for cable loops with anti-loosening clamping mechanism. Background Technology

[0002] Power systems commonly employ cable grounding loop resistance live-line testers. These devices monitor the cable's operating status online by applying a constant voltage source to the cable's grounding loop and collecting current signals. Typically, these devices consist of a housing integrating a control motherboard, lithium battery, and communication module, along with a solar panel for capturing solar energy. During installation, conventional methods often use threaded fasteners or simple U-shaped clamps to rigidly fix the housing and photovoltaic support directly to the power structure or frame outside the transformer. However, this traditional fixed structure, during long-term outdoor operation, suffers from several drawbacks. Because the integrated solar panel has a large area, in strong winds, it acts as a significant cantilevered wind-receiving surface. The captured wind load is amplified through the support arm, directly transmitting alternating stress to the connection between the housing and the support. Furthermore, the electromagnetic vibrations in the cable's operating environment, combined with low-frequency excitation induced by wind, can cause creep loss of the preload on the fixing bolts over time, leading to loosening and displacement of the tester.

[0003] To address the aforementioned issues, existing technologies offer several solutions; for example, increasing bolt specifications, adding spring washers, or applying thread-locking adhesive can be used to attempt to improve connection strength. However, these methods only delay loosening to a certain extent and cannot fundamentally absorb the physical impact of wind loads. Another example is the attempt by some designs to thicken the support steel plate or add reinforcing ribs to enhance structural rigidity; while this reduces deformation, it makes the overall equipment excessively heavy, increasing the difficulty of on-site installation. Furthermore, due to the lack of energy dissipation mechanisms, high-frequency vibrations can bypass the support and directly act on the internal precision ADC acquisition circuitry and sensor components, easily leading to fatigue fracture of weld points or drift in sampling accuracy. Yet another example is the attempt to use rubber bushings inside the support to achieve a flexible transition. However, such polymer materials are prone to aging and hardening under long-term ultraviolet radiation and alternating temperature differences in the field, failing within a short period, and failing to provide sufficient static clamping stiffness, causing the entire equipment to sway significantly in the wind, severely affecting the reliability of system operation. Summary of the Invention

[0004] The purpose of this invention is to provide an anti-loosening clamping online cable circuit resistance tester to solve the comprehensive mechanical instability problem of loss of connection pre-tightening force on the external frame and decreased system operational reliability of the online cable circuit resistance tester.

[0005] To achieve the above objectives, the present invention provides the following technical solution: An online cable loop resistance tester with anti-loosening clamping mechanism includes a tester body. The rear side of the tester body is provided with a first clamp and a second clamp, both of which are semi-circular. The first and second clamps are connected by vertically installed pins and are used to fit onto the outer wall of a utility pole. The inner wall of the second clamp has a through-hole mounting groove, and two symmetrically arranged springs are provided in the mounting groove. A wedge-shaped part is provided on the side of each spring that is close to the other. The block consists of two symmetrically arranged first wedge blocks, with a second wedge block that can slide up and down between them. The inclined surfaces of the two first wedge blocks are slidably connected to the inclined surfaces of the second wedge block. When the second wedge block moves downward, it drives the two first wedge blocks to compress the spring plates. A pull rope is fixedly connected to the lower end of the second wedge block. A one-way ratchet assembly is provided at the rear end of the second clamp. One end of the pull rope extends outside the second clamp and is fixedly connected to the one-way ratchet assembly. The one-way ratchet assembly is used to drive the pull rope to move downward.

[0006] By installing a clamping mechanism consisting of a first wedge block, a second wedge block, and a spring plate within the second pipe clamp, a one-way ratchet assembly is driven to pull the rope downwards during installation. This causes the second wedge block to compress the first wedge blocks on both sides using its inclined surface, driving the first wedge block towards the pole and compressing the spring plate. This elastic deformation of the spring plate allows it to tightly adhere to the outer wall of the pole, providing a high-strength mechanical clamping force for the detector body. This prevents loosening or slippage caused by the equipment's own weight or wind loads during long-term operation. Furthermore, the one-way ratchet assembly's unidirectional limiting effect on the rope ensures that the rope remains taut, locking the longitudinal displacement of the second wedge block. This effectively solves the problem of creep loss of preload in traditional threaded fasteners due to environmental wind load vibrations, ensuring the long-term stability of the detector under complex field conditions.

[0007] Preferably, the unidirectional ratchet assembly includes a ratchet, a first pawl, and a rope wheel. The ratchet and the rope wheel are coaxially arranged. The ratchet is rotatably connected to a second clamp. One end of the pull rope extending outside the second clamp is fixedly connected to the rope wheel. The first pawl is rotatably connected to the second clamp, and the first pawl engages with the ratchet teeth on the ratchet. The first pawl is used to restrict the ratchet to rotate only in one direction.

[0008] By incorporating a unidirectional stepping structure consisting of a ratchet, a pawl, and a pulley at the rear end of the second clamp, the rotating ratchet drives the coaxial pulley to rotate synchronously during tightening operations. This causes the pull rope to be wound onto the pulley in an orderly manner, generating longitudinal tension and achieving precise displacement control of the second wedge block. Furthermore, utilizing the unidirectional meshing characteristic between the pawl and the ratchet teeth, the pulley cannot reverse under the reaction force of the pull rope tension, thus converting the driving load into a stable static holding force. This avoids clamping force failure due to pull rope slack and ensures the self-locking reliability of the wedge clamping mechanism in unattended environments. Moreover, compared to direct manual pulling or rigid fixing, the coaxial combination of the pulley and ratchet provides higher mechanical gain, allowing the operator or automatic drive source to obtain greater pull rope tension with a smaller input torque. This simplifies the installation process while significantly improving the driving stroke accuracy of the second wedge block on the first wedge block and the spring.

[0009] Preferably, a second pawl is rotatably connected to the rear side of the second pipe clamp. The second pawl includes a connecting part and a deformable part. The connecting part is rotatably connected to the second pipe clamp. The deformable part is located at the end of the connecting part facing the ratchet. The deformable part engages with the ratchet teeth on the ratchet. The deformable part is made of shape memory metal.

[0010] By incorporating a second pawl containing a shape-memory metal deformation section on the rear side of the second clamp, the high sensitivity of shape-memory metal to ambient temperature allows the deformation section to elongate as the ambient temperature rises, driving the ratchet to rotate in small steps. When the temperature drops, the deformation section contracts, and the first pawl limits the ratchet, preventing it from reversing. Furthermore, the spontaneous action of the deformation section converts the ambient temperature difference into compensating tension for the pull rope, achieving automatic online compensation of the clamping mechanism's preload without human intervention. This effectively solves the problem of fixation failure caused by stress relaxation due to material thermal expansion and contraction or long-term operation. Moreover, compared to traditional rigid drive mechanisms, the shape-memory metal deformation section has a simple structure and requires no additional electricity. While fully utilizing natural environmental energy, it significantly reduces equipment maintenance costs and ensures that the second pawl can provide stable and continuous anti-loosening drive power even in harsh outdoor conditions.

[0011] Preferably, the second wedge block has grooves on both sides, the vertical projection section of the second wedge block is I-shaped, and the two first wedge blocks are slidably connected in the grooves on both sides of the second wedge block.

[0012] By designing the cross-section of the second wedge block as an I-shape and establishing a sliding connection between it and the first wedge block using the grooves on both sides, a precise mechanical guiding interface is provided for the relative movement between the first and second wedge blocks. This ensures that the second wedge block can synchronously and uniformly drive the first wedge blocks on both sides to smoothly extend and retract radially during longitudinal displacement. Furthermore, the I-shaped structure and the grooves form a mutually interlocking physical constraint, effectively preventing the first wedge block from circumferentially shifting or tilting when subjected to the reaction force of the pole. This ensures that the clamping force always acts perpendicularly on the spring, thereby significantly improving the transmission stability and stress distribution uniformity of the clamping mechanism. Moreover, compared to unconstrained inclined surface contact, the grooved sliding connection increases the force-bearing area of ​​the contact surface and reduces lateral swaying clearance. Even under severe vibrations induced by strong winds, the structural integrity of the wedge transmission chain can still be guaranteed, significantly reducing the risk of mechanical jamming and ensuring the rigidity and stability of the connection between the detector body and the pole.

[0013] Preferably, multiple rubber rings are coaxially arranged inside the first and second pipe clamps, and the multiple rubber rings are arranged in a linear array in the vertical direction.

[0014] By setting multiple rubber rings arranged in a linear array on the inner walls of the No. 1 and No. 2 clamps, when the clamps are fitted onto the outside of the pole, the high-friction physical properties of the rubber rings create multiple high-damping gripping points on the contact surface between the clamps and the pole. This significantly enhances the device's anti-slip capability in the vertical direction, effectively preventing vertical displacement of the detector body due to its own weight or external impact. Furthermore, the multi-array rubber rings provide flexible padding support for the clamps, adapting to the irregular concave and convex deformation of the pole surface. This not only effectively prevents direct wear of the outer protective layer of the pole by the rigid clamps but also reduces the fitting gap between the clamps and the pole through physical filling. Moreover, compared to integral padding, the linear array of rubber rings can form tiny drainage and ventilation channels between adjacent rubber rings while meeting clamping strength requirements. This avoids localized corrosion caused by rainwater accumulation or air pressure changes, improving the mechanical stability and service life of the detector in extreme outdoor climates from multiple dimensions.

[0015] Preferably, the vertical projection section of the spring is C-shaped, the opening of the spring faces the outside of the second clamp, and the two ends of the spring are provided with embedded parts, which are fixedly connected to the inner wall of the mounting groove and the outer wall of the first wedge block, respectively.

[0016] By designing the spring with a C-shaped cross-section and anchoring it between the inner wall of the mounting groove and the outer wall of the first wedge block using the embedded parts at both ends, the clamping mechanism is provided with a large elastic deformation compensation space when the second wedge block drives the first wedge block to move outward. The arc-shaped force-bearing surface formed by the C-shaped structure can generate uniform radial rebound stress under pressure, ensuring that there is always a dynamic elastic clamping force between the first wedge block and the pole, thereby effectively preventing mechanical gaps caused by creep or thermal shrinkage of the pole surface material. Furthermore, by facing the outside of the second clamp, the spring achieves maximum deformation freedom within the limited mounting groove space, effectively dispersing stress concentration caused by high-frequency vibration and avoiding the risk of fracture due to metal fatigue. Furthermore, compared to ordinary planar elastic elements, the C-shaped spring with the embedded fixing method not only enhances the structural stability of the assembly, but also provides a constant feedback force by utilizing its specific elastic characteristic curve. Even under physical deformation caused by extreme weather, it can still ensure the reliable gripping of the pole by the clamping mechanism, significantly improving the safety redundancy of the online monitoring instrument during long-term operation.

[0017] Preferably, the lower end of the detector body is provided with a connecting cable, the lower end of the connecting cable extends into the power receiving cabinet of the pole, and the lower end of the connecting cable is provided with an annular connecting piece, which is coaxially and fixedly connected to the power receiving post in the power receiving cabinet.

[0018] By installing a connecting cable extending into the junction cabinet at the lower end of the detector body, and using the ring-shaped terminal piece at the end to achieve a coaxial fixed connection with the terminal post, a standardized and highly stable electrical physical path is constructed for online monitoring of cable loop resistance, ensuring the integrity and continuity of the detection signal during transmission. Furthermore, the coaxial fixing of the ring-shaped terminal piece and the terminal post maximizes the effective contact area between conductors, significantly reducing the contact resistance and heat loss at the connection point. This effectively eliminates sampling data fluctuations caused by unstable connection points, ensuring the high-precision ADC acquisition circuit accurately captures weak resistance signals. Moreover, compared to traditional temporary measuring fixtures, this permanent coaxial fixed connection method possesses extremely strong anti-electromagnetic interference and environmental oxidation resistance, avoiding monitoring failures caused by loose wiring or poor contact. Combined with the aforementioned mechanical clamp fastening structure, it achieves comprehensive anti-loosening protection for the detector from mechanical grid connection to electrical connection, significantly improving the long-term operation and maintenance quality of the entire online monitoring system.

[0019] Preferably, the inner wall of the multiple rubber rings is provided with multiple protrusions, the multiple protrusions on each rubber ring are tooth-shaped, and the cross section of the protrusion is a right trapezoid, with the right-angled side of the protrusion located on the lower side.

[0020] By incorporating right-angled trapezoidal toothed protrusions on the inner walls of multiple rubber rings, the asymmetric mechanical properties of the right-angled trapezoidal structure are utilized. After the detector is installed, the right-angled sides of the protrusions serve as the primary vertical bearing surface, abutting against the outer wall of the pole. Since the right-angled sides are located on the lower side, when the detector is subjected to the downward force of gravity, the protrusions generate significant downward resistance, thus forming a unidirectional anti-slip structure similar to barbs in the longitudinal direction, significantly enhancing the vertical displacement resistance of the clamp. Furthermore, the inclined side design of the right-angled trapezoid facilitates the clamp's sliding into the predetermined position from top to bottom during installation, reducing installation resistance. In the locked state, the multiple toothed protrusions can deeply embed into the micropores or coating on the pole surface, forming a multi-point anchoring effect, effectively preventing the risk of periodic slippage caused by environmental wind vibration. Furthermore, compared to rubber rings with flat inner walls, the toothed protrusions not only increase local pressure for a more secure physical grip, but also provide a small amount of elastic compensation space for the material when deformed under pressure. This ensures that the rubber ring can maintain a constant static friction coefficient even under extreme temperature conditions, significantly improving the mechanical safety redundancy of the overall meshing of the detector.

[0021] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. This invention achieves continuous constant force pre-tightening through a wedge-shaped clamping structure combined with a one-way ratchet assembly, solving the problem of pre-tightening force creep loss in traditional threaded connections under long-term wind load vibration. Combined with the spontaneous temperature response of the shape memory metal deformation part, it can automatically convert environmental temperature difference energy into pre-tightening compensation force, achieving online automatic compensation of pre-tightening force without additional energy, and avoiding fixation loosening caused by material relaxation or thermal expansion and contraction.

[0022] 2. This invention utilizes an array of toothed rubber rings and C-shaped springs to work together. The asymmetrical toothed structure creates a one-way anti-slip "barb" effect, enhancing the stopping ability in the vertical direction. The C-shaped structure provides a stable elastic deformation space, evenly dispersing the stress concentration caused by high-frequency vibration, effectively reducing the risk of metal fatigue fracture, and significantly improving the long-term stability of the clamping structure under harsh outdoor conditions.

[0023] 3. This invention achieves a permanent fixed connection by using an annular contact piece and a contact post coaxially arranged at the end. While increasing the conductor contact area and reducing the contact resistance, it also achieves all-round anti-loosening protection from mechanical grid connection to electrical connection, effectively avoiding sampling data fluctuations caused by loose wiring, and significantly improving the long-term operation and maintenance reliability and detection accuracy of the online monitoring system for cable loop resistance. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the structure of the anti-loosening clamping cable loop resistance online tester during installation of the present invention; Figure 2 This is a schematic diagram of the overall structure of the anti-loosening clamping cable loop resistance online tester of the present invention; Figure 3 This is a schematic diagram of the structure of the No. 1 and No. 2 pipe clamps in this invention; Figure 4 for Figure 3 A magnified view of a section at point A in the middle; Figure 5 This is a top view of the No. 1 and No. 2 pipe clamps in this invention; Figure 6 for Figure 5 Full sectional view at point BB; Figure 7 for Figure 5 A magnified view of a section at point C; Figure 8 for Figure 5 Full sectional view at point DD; Figure 9 This is a schematic diagram of the connection between the annular contact piece and the terminal block in this invention.

[0025] In the diagram: 1. Detector body; 2. Pipe clamp No. 1; 3. Pipe clamp No. 2; 301. Mounting groove; 4. Pin; 5. Spring; 501. Embedded part; 6. Wedge block No. 1; 7. Wedge block No. 2; 701. Slide groove; 8. Pull rope; 9. Ratchet; 10. Pawl No. 1; 11. Rope pulley; 12. Pawl No. 2; 1201. Connecting part; 1202. Deformation part; 13. Rubber ring; 1301. Protrusion; 14. Annular grounding plate; 15. Electric pole; 16. Grounding cabinet; 17. Grounding post; 18. Knob; 19. Suspension; 20. Photovoltaic panel. Detailed Implementation

[0026] Please see Figures 1 to 9 This invention provides an online resistance tester for cable loops with anti-loosening clamping mechanism, the technical solution of which is as follows: For an online resistance tester for cable loops with anti-loosening clamping mechanism, please refer to [link / reference]. Figures 1 to 4 , Figure 8 and Figure 9The device includes a detector body 1. The detector body 1 has a first clamp 2 and a second clamp 3 on its rear side. Both the first clamp 2 and the second clamp 3 are semi-circular. The first clamp 2 and the second clamp 3 are connected by vertically installed pins 4 and are used to be fitted onto the outer wall of the pole 15. Multiple rubber rings 13 are coaxially arranged inside the first clamp 2 and the second clamp 3. The multiple rubber rings 13 are arranged in a linear array in the vertical direction. Multiple protrusions 1301 are provided on the inner wall of the multiple rubber rings 13. Each protrusion 1301 on the rubber ring 13 is toothed, and the cross-section of each protrusion 1301 is a right-angled trapezoid, with the right-angled side of the protrusion 1301 located on the lower side. A junction box 16 is fixedly installed on the pole 15. The junction box 16 contains three terminals, which are respectively connected to the three-phase lines of the power grid. A connecting cable is provided at the lower end of the detector body 1, and the lower end of the connecting cable extends into the junction box 16 of the pole 15. The lower end is provided with an annular contact piece 14, which is coaxially and fixedly connected to the contact post 17 in the power receiving cabinet 16; the front end of the first pipe clamp 2 is also provided with a suspension 19, which is fixedly connected to the first pipe clamp 2 by welding. A photovoltaic panel 20 is fixedly connected to the upper side of the suspension 19. The photovoltaic panel 20 is used to provide power to the detector body 1. The inner wall of the second pipe clamp 3 is provided with a mounting groove 301 that runs through both the upper and lower ends. Two symmetrically arranged springs 5 ​​are provided in the mounting groove 301. Two wedge blocks 6 are symmetrically arranged on one side of each other. A second wedge block 7 that can slide up and down is provided between the two wedge blocks 6. The inclined surfaces of the two wedge blocks 6 are slidably connected to the inclined surfaces of the second wedge block 7. When the second wedge block 7 moves down, it drives the two wedge blocks 6 to compress the spring 5. The vertical projection section of the spring 5 is C-shaped. The opening of the spring 5 faces the outside of the second clamp 3. The two ends of the spring 5 are provided with embedded parts 501, which are respectively connected to the mounting groove 3. The inner wall of 01 and the outer wall of the first wedge block 6 are fixedly connected; the left and right sides of the second wedge block 7 are provided with sliding grooves 701, the vertical projection section of the second wedge block 7 is I-shaped, the two first wedge blocks 6 are slidably connected in the sliding grooves 701 on both sides of the second wedge block 7, the lower end of the second wedge block 7 is fixedly connected with a pull rope 8, the rear end of the second pipe clamp 3 is provided with a one-way ratchet group, one end of the pull rope 8 extends to the outside of the second pipe clamp 3 and is fixedly connected to the one-way ratchet group, the one-way ratchet group is used to drive the pull rope 8 to move downward.

[0027] Please see Figure 6The one-way ratchet assembly includes a ratchet 9, a first pawl 10, and a rope pulley 11. The ratchet 9 and rope pulley 11 are coaxially arranged and share the same shaft. A knob 18 is coaxially fixedly connected to the end of the shaft furthest from the rope pulley 11. The knob 18 provides a gripping and twisting position for the operator. The ratchet 9 is rotatably connected to a second clamp 3. One end of the pull rope 8 extending outside the second clamp 3 is fixedly connected to the rope pulley 11. The first pawl 10 is rotatably connected to the second clamp 3. The first pawl 10 engages with the ratchet teeth on the ratchet 9 to restrict the ratchet 9 to rotate only in one direction. Furthermore, the second pawl 12 is rotatably connected to the rear side of the second clamp 3. The second pawl 12 includes a connecting part 1201 and a deformable part 1202. The connecting part 1201 is rotatably connected to the second clamp 3. The deformable part 1202 is located at the end of the connecting part 1201 facing the ratchet 9. The deformable part 1202 engages with the ratchet teeth on the ratchet 9. The deformable part 1202 is made of shape memory metal.

[0028] Working principle: Please refer to Figures 1 to 9During installation, after the No. 1 clamp 2 and the No. 2 clamp 3 are wrapped around the outside of the pole 15, the knob 18 is turned to drive the coaxial ratchet 9 and rope wheel 11 to rotate synchronously. The rope wheel 11 winds up the pull rope 8, pulling the No. 2 wedge block 7 to move downward in the vertical direction. The inclined surface of the No. 2 wedge block 7 presses against the inclined surfaces of the two No. 1 wedge blocks 6 on both sides, driving the two No. 1 wedge blocks 6 to move horizontally towards the outer wall of the pole 15, thereby compressing the C-shaped spring 5 to produce elastic deformation. Finally, the No. 1 wedge block 6, together with multiple rubber rings 13, clamps the pole 15. During this process, the No. 1 pawl 10 cooperates with the ratchet 9 to restrict the ratchet 9 from reversing, ensuring that the pull rope 8 is always in a taut and wound state, so that the clamping mechanism maintains a stable preload. After installation, when the ambient temperature rises, the pole 15 and the clamping mechanism undergo thermal expansion, which can easily lead to a decrease in the clamping preload. At this time, the shape memory metal deformation part 1202 will spontaneously deform as the temperature rises, pushing the pawl to further drive the ratchet 9 to rotate in the winding direction, automatically replenishing the loss of preload. When the ambient temperature drops, the deformation part 1202 returns to its original structure and will not hinder the locking state of the ratchet 9. Under long-term outdoor wind vibration conditions, the right-angled side of the right-angled trapezoidal toothed protrusion 1301 on the inner side of the rubber ring 13 serves as the lower vertical bearing surface, forming a one-way stop "barb" structure, preventing the detector body 1 from sliding downward due to its own weight. The drainage and venting channels between adjacent rubber rings 13 can avoid local corrosion caused by rainwater accumulation. The C-shaped spring 5 can disperse the stress concentration caused by high-frequency vibration through its own elastic deformation, avoiding metal fatigue fracture, while continuously providing uniform radial rebound stress, dynamically compensating for the gaps caused by the creep of the surface material of the pole 15, and always maintaining a stable clamping force. In terms of electrical connection, the end ring-shaped contact piece 14 is coaxially fixedly connected to the contact post 17, which increases the conductor contact area, reduces contact resistance, and reduces the interference of contact heating on detection accuracy. At the same time, it has strong anti-oxidation and anti-electromagnetic interference capabilities. Combined with a stable mechanical clamping structure, it achieves long-term anti-loosening in both mechanical and electrical dimensions, ensuring the long-term stable operation of online detection of cable circuit resistance.

[0029] The specific embodiment of the present invention has been described in detail above with reference to the accompanying drawings, but the present invention is not limited to the embodiments described above. For those skilled in the art, various changes, modifications, substitutions, and variations made to these embodiments without departing from the principles and ideas of the present invention should still fall within the protection scope of the present invention.

Claims

1. An online resistance tester for cable loops with anti-loosening clamping mechanism, comprising a tester body (1), characterized in that, The detector body (1) has a first clamp (2) and a second clamp (3) on its rear side. Both the first clamp (2) and the second clamp (3) are semi-circular. The first clamp (2) and the second clamp (3) are connected by vertically installed pins (4) for mounting on the outer wall of the pole (15). The inner wall of the second clamp (3) has a mounting groove (301) that runs through both the upper and lower ends. The mounting groove (301) has two symmetrically arranged springs (5). The two springs (5) have a first wedge block (6) on the side of each spring (5) that is close to each other. The blocks (6) are symmetrically arranged. A second wedge block (7) that can slide up and down is provided between the two first wedge blocks (6). The inclined surfaces of the two first wedge blocks (6) are slidably connected to the inclined surfaces of the second wedge block (7). When the second wedge block (7) moves down, it drives the two first wedge blocks (6) to compress the spring (5). A pull rope (8) is fixedly connected to the lower end of the second wedge block (7). A one-way ratchet group is provided at the rear end of the second pipe clamp (3). One end of the pull rope (8) extends to the outside of the second pipe clamp (3) and is fixedly connected to the one-way ratchet group. The one-way ratchet group is used to drive the pull rope (8) to move downward.

2. The anti-loosening clamping type online cable circuit resistance tester according to claim 1, characterized in that, The unidirectional ratchet assembly includes a ratchet (9), a first pawl (10), and a rope wheel (11). The ratchet (9) and the rope wheel (11) are coaxially arranged. The ratchet (9) is rotatably connected to the second clamp (3). The end of the pull rope (8) extending outside the second clamp (3) is fixedly connected to the rope wheel (11). The first pawl (10) is rotatably connected to the second clamp (3), and the first pawl (10) engages with the ratchet teeth on the ratchet (9). The first pawl (10) is used to restrict the ratchet (9) to rotate only in one direction.

3. The anti-loosening clamping type online cable circuit resistance tester according to claim 2, characterized in that, The rear side of the second pipe clamp (3) is rotatably connected to the second pawl (12). The second pawl (12) includes a connecting part (1201) and a deformable part (1202). The connecting part (1201) is rotatably connected to the second pipe clamp (3). The deformable part (1202) is located at the end of the connecting part (1201) facing the ratchet (9). The deformable part (1202) engages with the ratchet teeth on the ratchet (9). The deformable part (1202) is made of shape memory metal.

4. The anti-loosening clamping type online cable circuit resistance tester according to claim 1, characterized in that, The second wedge block (7) has grooves (701) on both sides. The vertical projection section of the second wedge block (7) is I-shaped. The two first wedge blocks (6) are slidably connected in the grooves (701) on both sides of the second wedge block (7).

5. The anti-loosening clamping type online cable circuit resistance tester according to claim 1, characterized in that, Multiple rubber rings (13) are coaxially arranged inside the first pipe clamp (2) and the second pipe clamp (3), and the multiple rubber rings (13) are arranged in a linear array in the vertical direction.

6. The anti-loosening clamping type online cable circuit resistance tester according to claim 1, characterized in that, The vertical projection section of the spring (5) is C-shaped. The opening of the spring (5) faces the outside of the second pipe clamp (3). The two ends of the spring (5) are provided with embedded parts (501). The embedded parts (501) are fixedly connected to the inner wall of the mounting groove (301) and the outer wall of the first wedge block (6), respectively.

7. The anti-loosening clamping type online cable circuit resistance tester according to claim 1, characterized in that, The lower end of the detector body (1) is provided with a connecting cable, the lower end of which extends into the power receiving cabinet (16) of the pole (15). The lower end of the connecting cable is provided with an annular connecting piece (14), which is coaxially and fixedly connected to the power receiving post (17) in the power receiving cabinet (16).

8. The anti-loosening clamping type online cable circuit resistance tester according to claim 5, characterized in that, Multiple protrusions (1301) are provided on the inner sidewall of the multiple rubber rings (13). The multiple protrusions (1301) on each rubber ring (13) are toothed, and the cross section of the protrusion (1301) is a right trapezoid, with the right-angled side of the protrusion (1301) located on the lower side.

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