A deep buried cable detector

Abstract

The application belongs to the technical field of cable detection instrument, and particularly relates to a large-buried-depth cable detection instrument, which comprises a detection instrument body, the detection instrument body comprises a fixed section, a movable section and a moving section, the fixed section, the movable section and the moving section are arranged in sequence from top to bottom, a detection module is arranged on the movable section, the bottom of the fixed section is hingedly connected to the moving section, the top of the movable section is hingedly connected to the fixed section, an adjusting assembly is arranged on the fixed section, the adjusting assembly is connected to the movable section and the moving section at both ends, and the adjusting assembly drives the movable section to synchronously and reversely rotate to correct when the adjusting assembly rotates based on the hinge joint point between the fixed section and the moving section, the moving section comprises two groups of rotating wheel groups, each rotating wheel group comprises a roller and a supporting shell, the roller is rotatably arranged on the supporting shell, the two sides of the fixed section are respectively hingedly connected to the two groups of supporting shells, and the detection path of the movable section is formed between the two groups of rotating wheel groups, which can adjust the detection module to be always perpendicular to the ground according to the angle of the receiver.

Description

Technical Field

[0001] This invention belongs to the technical field of cable detectors, specifically relating to a deep-buried cable detector. Background Technology

[0002] Cable detectors are primarily based on the principle of electromagnetic induction. Their core workflow involves a transmitter applying a specific frequency alternating current signal to the target cable. This signal propagates along the cable and induces an electromagnetic field around it. Subsequently, a handheld receiver detects this electromagnetic field on the ground. By analyzing the signal's strength, direction, and variation patterns, the precise path, depth, and direction of the underground cable can be determined. While the technology is relatively mature for conventional detection, it faces challenges such as interference from densely packed pipelines. However, detecting cables at great depths presents a significant technical challenge, focusing on addressing the fundamental problems of rapid signal attenuation and extremely low signal-to-noise ratio. This requires the transmitter to output sufficiently high power and prioritize low-frequency signals to enhance penetration, while the receiver must possess extremely high sensitivity and advanced digital signal processing capabilities to extract weak signals from complex environmental noise.

[0003] However, when facing the detection scenario of deep-buried cables (usually referring to depths exceeding 3 meters), it is necessary for staff to hold the detector receiver for a long time to receive signals, which makes it difficult to operate the equipment for extended periods. To address this, Chinese Patent Publication No. CN120405772A discloses a deep-buried cable detector based on weak signal detection. It includes a detector body and a moving mechanism. The moving mechanism is located on the outer wall of the detector body and includes a fixed block and a rotating wheel. The rotating wheel is equipped with multiple rollers and is connected to the fixed block through a buffer assembly. The existing detector's roller design means it can only be pushed forward in a completely upright position during use. However, pushing it forward while holding it upright by the handle makes it difficult to generate effective forward thrust. If it is pushed forward at an angle, the detector module will form an angle with the ground. To effectively capture and accurately analyze the extremely weak electromagnetic signals generated by deeply buried cables, the induction coil inside the receiver must be kept relatively perpendicular to the ground to obtain the maximum magnetic field coupling efficiency and the correct geometric measurement reference. However, the existing handheld structure of the receiver lacks an effective attitude control guarantee and real-time calibration mechanism. In the actual complex field operation environment, if the detector module is not in a relatively vertical position and the receiver tilts, the antenna coupling efficiency will decrease, further attenuating the already weak effective signal and completely drowning it out by environmental noise, leading to detection failure.

[0004] Based on this, in order to solve the problem that the detection accuracy and precision of deep-buried cables are low due to the inability to keep the receiver vertical when handheld in the existing technology. Therefore, a deep-buried cable detector is proposed. Summary of the Invention

[0005] To address the aforementioned problems in the existing technology, this invention provides a deep-buried cable detector.

[0006] The objective of this invention can be achieved through the following technical solutions: This invention discloses a deep-buried cable detector, comprising a detector body, which includes a fixed section, a movable section, and a moving section arranged sequentially from top to bottom. A detection module is mounted on the movable section. The bottom of the fixed section is hinged to the moving section, and the top of the movable section is hinged to the fixed section. An adjustment component is mounted on the fixed section, with its two ends connected to the movable section and the moving section, respectively. When the fixed section rotates based on its hinge point with the moving section, the adjustment component drives the movable section to rotate synchronously in the opposite direction based on its hinge point with the fixed section for correction.

[0007] As a further embodiment of the present invention, the hinge point between the bottom of the fixed section and the bottom of the movable section, and the hinge point between the top of the movable section and the fixed section, are both located on the corner near the operator.

[0008] As a further embodiment of the present invention, the moving section includes two sets of rotating wheel sets, each set of rotating wheel sets including rollers and a support housing. The rollers are rotatably mounted on the support housing. The two sides of the fixed section are respectively hinged to the two sets of support housings, and the two sets of rotating wheel sets form the detection path of the moving section.

[0009] As a further embodiment of the present invention, the adjustment assembly includes a first arc-shaped rack respectively disposed on the support housing and extending toward the hinge side, a second arc-shaped rack disposed on the movable section and extending toward the hinge side, a first gear and a second gear disposed on the fixed section and meshing with the first arc-shaped rack and the second arc-shaped rack respectively, and a transmission rack disposed on the fixed section and meshing with the first gear and the second gear.

[0010] As a further aspect of the present invention, a damper is also included, which is disposed on the fixed section and connected to one end of the transmission rack.

[0011] As a further embodiment of the present invention, the first gear and the second gear are respectively meshed on the outer sides of the first arc-shaped rack and the second arc-shaped rack.

[0012] As a further embodiment of the present invention, a bushing is provided inside the support housing, the rotation shaft of the roller is rotatably disposed inside the bushing, and a spring is provided between the top of the bushing and the top of the inner side of the support housing.

[0013] As a further embodiment of the present invention, the spring includes an upper spring and a lower spring, and a rocker arm locking hook is provided between the upper spring and the lower spring, facing the fixed section. The rocker arm locking hook is provided with a rotating shaft and is rotatably disposed on the side wall of the support housing. The fixed section is provided with a fixed locking hook facing the moving section. The rocker arm locking hook and the fixed locking hook are engaged with each other. The fixed section applies pressure to the moving section, causing the bushing to rise relative to the fixed section in the support housing and pushing the rocker arm locking hook to unlock and separate from the fixed locking hook.

[0014] As a further embodiment of the present invention, a first cylinder is provided between the fixed section and the moving section, and a second cylinder is provided inside the support housing. The push rod of the first cylinder is provided on the side of the support housing, and the cylinder body of the first cylinder is provided on the side of the fixed section. The second cylinder is provided between the bottom of the inner side of the support housing and the bushing. The first cylinder and the second cylinder are interconnected. The fixed section rotates and tilts based on the support housing and stretches the first cylinder body to drive the second cylinder body to lower the height of the bushing inside the support housing. When the fixed section resets, it compresses the first cylinder and drives the second cylinder to raise the height of the bushing inside the support housing.

[0015] As a further embodiment of the present invention, the roller is a three-wheeled star-shaped roller.

[0016] The beneficial effects of this invention are as follows: A closed loop of forced attitude correction is established through a three-section hinged structure and adjustment components. When the operator applies a pushing force, the fixed section, as the main force-bearing component, will inevitably tilt. This tilting action is immediately sensed by the adjustment components and converted into a driving force on the movable section. Since the rotation direction of the movable section is opposite to that of the fixed section, when the fixed section tilts backward, the movable section and its detection module always maintain a relatively perpendicular state to the ground. Through the adaptive vertical maintenance of the detection module's attitude, the problem of sacrificing the verticality of the detection module for ease of maneuvering, as seen in traditional integrated or simple hinged structures, is completely solved. This ensures that the receiving coil is always aligned with the vertical magnetic lines of force generated by the underground cable at maximum coupling efficiency, effectively capturing the weak signals from deeply buried cables, fundamentally improving the success rate and data accuracy of detection. Attached Figure Description

[0017] To facilitate understanding by those skilled in the art, the present invention will be further described below with reference to the accompanying drawings.

[0018] Figure 1 This is a schematic diagram of the internal structure of the present invention from the front. Figure 2 for Figure 1 Enlarged structural diagram at point A; Figure 3 This is a schematic diagram of the internal structure of the side of the present invention; Figure 4 for Figure 3 Enlarged structural diagram at point B; Figure 5 This is a schematic diagram of the internal structure of the support shell of the present invention; Figure 6 for Figure 5 A magnified structural diagram at point C.

[0019] Explanation of reference numerals in the attached drawings: 1. Fixed section; 2. Movable section; 3. Roller; 4. Support housing; 5. Second cylinder; 6. Rocker arm lock hook; 7. First cylinder; 8. Bushing; 9. First hinge shaft; 10. Second hinge shaft; 11. First arc-shaped rack; 12. Second arc-shaped rack; 13. First gear; 14. Second gear; 15. Transmission rack; 16. Damper; 17. Fixed lock hook. Detailed Implementation

[0020] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] like Figures 1-6 As shown, a deep-buried cable detector of the present invention includes a detector body, which includes a fixed section 1, a movable section 2, and a moving section. The fixed section 1, movable section 2, and moving section are arranged sequentially from top to bottom. A detection module is provided on the movable section 2. The bottom of the fixed section 1 is hinged to the moving section, and the top of the movable section 2 is hinged to the fixed section 1. An adjustment component is provided on the fixed section 1. The two ends of the adjustment component are respectively connected to the movable section 2 and the moving section. When the fixed section 1 rotates based on the hinge point with the moving section, the adjustment component drives the movable section 2 to rotate synchronously in the opposite direction based on the hinge point with the fixed section 1 for correction.

[0022] The adjustment component is a linkage mechanism with its two ends connected to the movable segment 2 and the moving segment, respectively. When the operator pushes the handle to move the entire device forward, causing the fixed segment 1 to rotate and tilt backward towards the operator based on its hinge point with the moving segment (first hinge axis 9), the adjustment component simultaneously drives the movable segment 2 to rotate in the opposite direction based on its hinge point with the fixed segment 1 (second hinge axis 10). Fixed plates extend from both sides of the fixed segment 1 downwards, creating a mounting space for the movable segment 2 between the two fixed plates. The bottom rear end of the fixed plate is hinged to the moving segment, forming the first hinge axis 9, while the movable segment 2 is hinged to its top rear end between the two fixed plates, forming the second hinge axis 10 between the movable segment 2 and the fixed plates. Through this three-segment hinge structure and adjustment component, a closed loop for forced attitude correction is established. When the operator applies a pushing force, the fixed segment 1, as the primary force-bearing component, will inevitably tilt. This tilting action is immediately sensed by the adjustment component and converted into a driving force on the movable segment 2. Since the rotation direction of the movable section 2 is opposite to that of the fixed section 1, when the fixed section 1 tilts backward, the movable section 2 and its detection module always remain relatively perpendicular to the ground. Because the cable is buried underground primarily to maintain a constant distance from the ground surface, when on a sloped surface, the movable section 2 only needs to maintain perpendicularity to the ground surface, not perpendicularity to the horizontal plane.

[0023] By adaptively maintaining the vertical orientation of the detection module, the problem of sacrificing the verticality of the detection module for ease of deployment, as seen in traditional integrated or simple articulated structures, is completely solved. This ensures that the receiving coil is always aligned with the vertical magnetic lines of force generated by the underground cable at maximum coupling efficiency, effectively capturing the weak signals from cables buried at great depths, fundamentally improving the success rate and data accuracy of detection.

[0024] As a further aspect of the invention, the hinge points between the bottom of the fixed section 1 and the bottom of the movable section, and between the top of the movable section 2 and the fixed section 1, are both located at the corners closer to the operator. By placing both the first hinge shaft 9 and the second hinge shaft 10 on the side closer to the operator, the fixed end can be tilted towards the operator during use, maintaining the fixed section 1 at a natural, ergonomic tilting angle. This not only reduces the adjustment burden on the adjustment components but also makes the operator's pushing feel smoother and more natural.

[0025] As a further embodiment of the present invention, the moving section includes two sets of rotating wheel groups, each consisting of rollers 3 and a supporting housing 4. The rollers 3 are rotatably mounted on the supporting housing 4. The two sides of the fixed section 1 are respectively hinged to the two sets of supporting housings 4, forming the detection path of the moving section 2 between the two sets of rotating wheel groups. Specifically, the two sets of rotating wheel groups are arranged on both sides of two fixed plates, while the moving section 2 is located between the two fixed plates. The detection path of the moving section 2 is vertically downward, and there are no metal parts obstructing the ground area directly below the detection module. Moving mechanisms such as rollers 3 typically contain metal parts, which, if placed directly below the detection module, would cause near-field interference to weak electromagnetic signals. In this embodiment, the detection module is placed between the two sets of rollers 3, completely avoiding metal parts in the detection area, thus greatly improving the signal-to-noise ratio.

[0026] As a further embodiment of the present invention, the adjustment assembly includes a first arc-shaped rack 11 respectively disposed on the support housing 4 and extending toward the hinge side, a second arc-shaped rack 12 disposed on the movable section 2 and extending toward the hinge side, a first gear 13 and a second gear 14 disposed on the fixed section 1 and meshing with the first arc-shaped rack 11 and the second arc-shaped rack 12 respectively, and a transmission rack 15 disposed on the fixed section 1 and meshing with the first gear 13 and the second gear 14.

[0027] When the fixed segment 1 tilts forward around the first hinge axis 9, the angle of the fixed segment 1 relative to the supporting housing 4 changes. Since the first gear 13 is fixed to the fixed segment 1 and the first arc-shaped rack 11 is fixed to the supporting housing 4, the relative movement of the two forces the first gear 13 to rotate. The rotation of the first gear 13 is transmitted to the second gear 14 through the transmission rack 15. The rotation of the second gear 14 drives the second arc-shaped rack 12 that meshes with it. Since the second arc-shaped rack 12 is fixed to the movable segment 2, it drives the movable segment 2 to rotate in the opposite direction around the second hinge axis 10. By providing a purely mechanical, non-electrical forced linkage scheme, it has extremely high reliability and environmental adaptability. It requires no sensors, controllers, or motors, is low in cost, responds quickly, has no delay, and can still work stably in harsh environments such as muddy water and low temperatures in the field. It perfectly achieves a 1:1 precise attitude compensation of "how much the fixed segment 1 tilts, how much the movable segment 2 corrects in the opposite direction".

[0028] As a further aspect of the invention, a damper 16 is also included. The damper 16 is disposed on the fixed section 1 and connected to one end of the transmission rack 15. When the transmission rack 15 moves up and down under the drive of the first gear 13 and the second gear 14, it must overcome the resistance provided by the damper 16. During the operator's walking, the arm will naturally bounce and shake. The damper 16 can effectively absorb this high-frequency, small-amplitude vibration, preventing the adjustment component from responding too sensitively to these unintended vibrations, keeping the posture of the detection module stable, and avoiding signal jitter. Providing appropriate damping force allows the operator to feel a certain "sucking sensation" or resistance when tilting the fixed section 1, preventing the mechanism from being too loose, and improving the operating feel and control accuracy.

[0029] As a further aspect of the present invention, the first gear 13 and the second gear 14 are respectively meshed on the outer sides of the first arc-shaped rack 11 and the second arc-shaped rack 12. This outer meshing method, compared to inner meshing or end-face meshing, fully utilizes the spare space on the outer sides of the supporting housing 4 and the fixed section 1, avoiding interference between the gears and racks in the narrow internal space, and facilitating installation and maintenance. The outer meshing also allows the gear pitch circle diameter to be unrestricted by the internal space, enabling the selection of a more suitable gear module and number of teeth, resulting in smoother and more efficient transmission.

[0030] As a further embodiment of the present invention, a bushing 8 is provided inside the support housing 4, and the rotating shaft of the roller 3 is rotatably disposed inside the bushing 8. A spring is provided between the top of the bushing 8 and the top of the inner side of the support housing 4. The spring includes an upper spring and a lower spring, and a rocker arm locking hook 6 is provided between the upper spring and the lower spring, facing the fixed section 1. A rotating shaft is provided on the rocker arm locking hook 6 and rotatably disposed on the side wall of the support housing 4. A fixed locking hook 17 is provided on the fixed section 1, facing the moving section. The rocker arm locking hook 6 and the fixed locking hook 17 are interlocked. The fixed section 1 applies pressure to the moving section, causing the bushing 8 to rise relative to the fixed section 4 and pushing the rocker arm locking hook 6 to unlock and separate from the fixed locking hook 17.

[0031] When roller 3 is impacted by the ground, the rotating shaft transmits the impact force to bushing 8. Bushing 8 compresses the spring and slides vertically inside the support housing 4, thus providing cushioning. This provides vertical shock absorption for the detector. Deep-buried exploration is usually conducted on unpaved roads in the field, where the ground is rugged. Vertical shock absorption effectively absorbs impact energy, protecting the precision detection module from vibration damage. At the same time, it keeps roller 3 in contact with the ground, ensuring smooth propulsion and indirectly guaranteeing the stability of the attitude adjustment system.

[0032] Locked State: When the detector is lifted or roller 3 is suspended, the spring is relaxed or slightly compressed, and bushing 8 is in a low position, not in contact with rocker arm locking hook 6. Rocker arm locking hook 6 engages with fixed locking hook 17 under its own weight or the action of torsion spring, locking the fixed section 1 and the moving section to prevent them from rotating freely.

[0033] Unlocked State: When the detector is placed on the ground, the entire weight of the device rests on the moving section via the fixed section 1. It remains locked in the absence of external force, allowing the detector to be pushed and probed in a completely vertical position. When tilting is required, the operator holds the device on the fixed section 1 and applies pressure to the moving section. This pressure forces the bushing 8 to rise relative to the support housing 4 (i.e., the support housing 4 falls relative to the bushing 8), compressing the upper and lower springs. The rise of the bushing 8 pushes the swing arm locking hook 6 to rotate, disengaging it from the fixed locking hook 17. When the detector is lifted, the fixed section 1 and the moving section are locked, preventing wobbling and tipping, facilitating transport and storage. When the detector is placed on the ground for probe preparation, applying pressure to the fixed section 1 releases the lock, and the attitude adjustment system immediately takes effect, simplifying the operation. Simultaneously, the upper and lower springs provide two levels of cushioning, effectively absorbing heavy impacts and minor vibrations.

[0034] Because the distance between the detection module on the movable section 2 and the ground needs to be kept relatively constant during the detection cable process, and the different tilt angles of the fixed section 1 will cause the distance between the detection module on the movable section 2 and the ground to change, in order to avoid this problem.

[0035] As a further embodiment of the present invention, a first cylinder 7 is disposed between the fixed section 1 and the moving section, and a second cylinder 5 is disposed inside the support housing 4. The push rod of the first cylinder 7 is disposed on the side of the support housing 4, and the cylinder body of the first cylinder 7 is disposed on the side of the fixed section 1. The second cylinder 5 is disposed between the bottom inner side of the support housing 4 and the bushing 8. The first cylinder 7 and the second cylinder 5 are interconnected. The fixed section 1 rotates and tilts based on the support housing 4, and stretches the first cylinder body to drive the second cylinder body to lower the height of the bushing 8 inside the support housing 4. When the fixed section 1 resets, it compresses the first cylinder 7 and drives the second cylinder 5 to raise the height of the bushing 8 inside the support housing 4. The first cylinder 7 and the second cylinder 5 are filled with gas.

[0036] When the operator presses down on the handle to tilt the fixed section 1 backward, the cylinder body of the first cylinder 7 remains in a fixed position on the moving section, while the push rod of the first cylinder 7 gradually moves from near to far from the cylinder body on the fixed section 1. This causes gas to be drawn from the second cylinder 5 within the first cylinder 7, resulting in a decrease in the height of the bushing 8 within the support housing 4. Since the height of the roller 3's shaft remains constant, the support housing 4 rises relative to the ground as the distance between the bushing 8 and the bottom of the support housing 4 shortens, thus offsetting the change in the height of the detection module caused by the tilt angle and maintaining a constant distance between the detection module and the ground. This is crucial for scenarios requiring close-to-the-ground detection. Conversely, as the fixed section 1 gradually reverses and resets, the push rod of the first cylinder 7 moves from far to near the cylinder body on the fixed section 1. This forces the gas inside the first cylinder 7 into the cylinder body of the second cylinder 5, relatively lengthening the distance between the bushing 8 and the bottom of the support housing 4, and thus reducing the height of the support housing 4 relative to the ground.

[0037] As a further embodiment of the present invention, roller 3 is a three-wheeled star-shaped wheel. Compared to a single wheel or two wheels, the star-shaped wheel can "climb" over obstacles such as rocks, ditches, and tree roots instead of crashing into them, significantly improving the detector's passability in complex woodlands, wastelands, and other unstructured terrains. Simultaneously, the alternating contact of multiple wheels with the ground transforms sliding friction into rolling friction and decomposes continuous, large-amplitude bumps into discrete, small-amplitude vibrations. Combined with the shock absorption system, this further ensures the stability of the detection module.

[0038] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

Claims

1. A deep-buried cable detector, characterized in that: The device includes a detector body comprising a fixed section, a movable section, and a moving section, arranged sequentially from top to bottom. A detection module is mounted on the movable section. The bottom of the fixed section is hinged to the moving section, and the top of the movable section is hinged to the fixed section. An adjustment component is mounted on the fixed section, with its two ends connected to the movable section and the moving section, respectively. When the fixed section rotates based on its hinge point with the moving section, the adjustment component drives the movable section to rotate synchronously in the opposite direction based on its hinge point with the fixed section for correction.

2. The cable detector for deep burial as described in claim 1, characterized in that: The hinge point between the bottom of the fixed section and the bottom of the movable section, and the hinge point between the top of the movable section and the fixed section, are both located on the corner near the operator.

3. The cable detector for deep burial as described in claim 2, characterized in that: The moving section includes two sets of rotating wheel groups, each set including rollers and a support housing. The rollers are rotatably mounted on the support housing. The fixed section is hinged to the two sets of support housings on both sides. The two sets of rotating wheel groups form the detection path of the moving section.

4. The cable detector for deep burial as described in claim 3, characterized in that: The adjustment assembly includes a first arc-shaped rack disposed on the support housing and extending toward the hinge side, a second arc-shaped rack disposed on the movable section and extending toward the hinge side, a first gear and a second gear disposed on the fixed section and meshing with the first arc-shaped rack and the second arc-shaped rack, respectively, and a transmission rack disposed on the fixed section and meshing with the first gear and the second gear.

5. A deep-buried cable detector according to claim 4, characterized in that: It also includes a damper, which is disposed on the fixed section and connected to one end of the transmission rack.

6. The cable detector for deep burial as described in claim 4, characterized in that: The first gear and the second gear mesh with the outer sides of the first arc-shaped rack and the second arc-shaped rack, respectively.

7. A deep-buried cable detector according to claim 3, characterized in that: A bushing is provided inside the support housing, and the rotating shaft of the roller is rotatably disposed inside the bushing. A spring is provided between the top of the bushing and the top of the inner side of the support housing.

8. A deep-buried cable detector according to claim 7, characterized in that: The spring includes an upper spring and a lower spring. A rocker arm locking hook is provided between the upper spring and the lower spring, facing the fixed section. A pivot is provided on the rocker arm locking hook and is rotatably mounted on the side wall of the support housing. A fixed locking hook is provided on the fixed section, facing the moving section. The rocker arm locking hook and the fixed locking hook are interlocked. The fixed section applies pressure to the moving section, causing the bushing inside the support housing to rise relative to each other and push the rocker arm locking hook to unlock and separate from the fixed locking hook.

9. A deep-buried cable detector according to claim 1, characterized in that: A first cylinder is disposed between the fixed section and the moving section, and a second cylinder is disposed inside the support housing. The push rod of the first cylinder is disposed on the side of the support housing, and the cylinder body of the first cylinder is disposed on the side of the fixed section. The second cylinder is disposed between the bottom inner side of the support housing and the bushing. The first cylinder and the second cylinder are interconnected. The fixed section rotates and tilts based on the support housing and stretches the first cylinder body to drive the second cylinder body to lower the height of the bushing inside the support housing. When the fixed section resets, it compresses the first cylinder and drives the second cylinder to raise the height of the bushing inside the support housing.

10. A deep-buried cable detector according to claim 3, characterized in that: The roller is a three-wheeled star-shaped roller.

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