JP2019207189A - Metal detection system and metal detection method - Google Patents

Abstract

To provide a versatile metal detection system and a metal detection method capable of accurately detecting a buried position of a buried pipe.SOLUTION: A metal detection system 1 comprises: an excavator 10 having booms 12A and 12B capable of penetrating the ground and a bucket 13; and a power supply device 20 for applying AC current AC to a water pipe P. The excavator 10 includes a magnetic field detection unit 16 for detecting a magnetic field M generated in the water pipe P by application of the AC current AC from the power supply device 20. The power supply device 20 varies frequency of the AC current AC applied to the water pipe P depending on the degree of approaching of the bucket 13 or the like to the water pipe P.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a metal exploration system and a metal exploration method, and more particularly to a metal exploration system and a metal exploration method capable of confirming the presence of a long metal object (for example, a metal pipe) embedded in the ground. It is.

  Conventionally, when excavating a road using a drilling machine (for example, excavator), check the status of buried pipes laid near the construction site in advance with a management company such as a gas company. In order to prevent the buried pipe from being broken or damaged, the exploration device is used to explore the buried pipe.

  However, even if such work is performed in advance, the position of the buried pipe that is actually buried is different, or there are not many cases where the unexpected buried pipe is buried. There was a risk of damaging and damaging buried pipes during excavation work.

In order to solve such problems, for example, a technique as described in Patent Document 1 has been proposed.
The technique of this patent document 1 is
(A) A transponder in which predetermined information is stored is fixed in advance in a pipe and buried.
(B) After that, when excavating underground, the presence of the buried pipe is detected by issuing an interrogation signal from a transmission / reception device attached to the excavating machine and receiving a response signal from the transponder.
It is comprised as follows.

  According to such a technique, since the presence of the buried pipe can be accurately detected, it is possible to prevent the buried pipe from being broken or damaged by the excavating machine.

Japanese Patent Laid-Open No. 07-317107

  However, the technique of Patent Document 1 has a problem in that it is practically difficult to obligate all of the pipes to be buried because the transponder must be fixed in advance when the pipes are buried in the ground. It was.

  In this respect, the technique of Patent Document 1 cannot be said to have greatly contributed in terms of preventing breakage / damage of the buried pipe, but has room for improvement in terms of versatility.

By the way, among the buried pipes constituting the so-called lifeline, in particular, in the gas pipe and the water and sewage pipe, the fact is that most of them are formed by “metal members”.
Considering such a situation, it can be said that excavation work is extremely important while grasping the position of the buried pipe made of “metal member”.

  The present invention has been made to solve such a problem, and is to provide a metal exploration system and a metal exploration method that are highly versatile and capable of accurately detecting an embedded position of an embedded pipe. is there.

  According to the metal exploration system of the present invention, the above-described problem has an underground entry portion that can enter the underground, and the underground operation is performed by causing the underground entry portion to enter the underground. A metal exploration system comprising a working device and a power feeding device for applying a current to a conductive buried object buried in the ground, wherein the metal exploration system is provided in the underground entry portion, and a current is supplied by the power feeding device. A magnetic field detection unit that detects a magnetic field generated in the embedded object when applied to, and an approach degree that calculates an approach degree of the underground entry part to the embedded object based on the magnetic field detected by the magnetic field detection unit The power supply device includes a frequency variable unit that varies a frequency of the current applied to the embedment object according to the approach degree calculated by the approach degree calculator. It is.

  Similarly, according to the metal exploration method according to the present invention, the above-described problem is applied to a current application process for applying a current to a buried object having conductivity embedded in the ground, and an underground work device for performing underground work. A magnetic field detection unit provided in the underground entry unit detects a magnetic field generated in the buried object by performing an underground entry step in which the provided underground entry unit enters the ground and the current application step. A magnetic field detection step, and an approach degree calculation step of calculating an approach degree of the underground approach portion with respect to the embedded object based on the magnetic field detected by performing the magnetic field detection step, and the current application step includes And a frequency variable step of varying a frequency of the current applied to the burying object in accordance with the approach degree calculated by performing the approach degree calculating step. It is possible to attain.

  The “underground work device” mentioned here is a concept that includes all kinds of devices that can be used for underground work, such as excavators that excavate soil and holes in the ground. In addition to a machine such as a boring machine, it is meant to include a hand-held type, for example, a so-called exploration rod or scoop that pierces into the ground to explore underground objects.

  The “underground entry part” is, for example, a shovel car, a bucket for scooping earth and sand, etc., an exploration rod, a part to be entered into the ground is a scoop, and earth and sand etc. The scooped parts correspond to each.

  Further, the “embedding target” is a concept including any and all conductive members capable of passing an electric current, and representative examples thereof include pipes made of metal members (for example, gas pipes and water and sewage pipes). Can be mentioned.

In the above configuration,
(A) Applying an electric current to the “embedding target” so that the “magnetic field” generated around the “embedding target” can be detected by the “magnetic field detection unit” provided in the “underground entry part”.
(B) Let the “underground approach” enter the ground,
(C) calculating the degree of approach of the “underground entry part” with respect to the “buried object”;
(D) Varying the frequency of the current applied to the “buried object” in accordance with the degree of approach of the “underground approaching part” to the “buried object”.
It is configured as follows.

  That is, in the above configuration, since the “magnetic field” generated around the “embedding target” can be detected by the “magnetic field detection unit” provided in the “underground approaching part”, the “embedding target” with relatively high accuracy. Can be confirmed. In this respect, it can be said that the above configuration can effectively prevent the “buried object” from being damaged or damaged during underground work.

  Further, in the above configuration, any “embedding target” can be explored as long as it can flow current, so that it can be highly versatile.

  Furthermore, in the said structure, it is comprised so that the frequency of the electric current applied to "embedding object" may be changed as the "underground approach part" approachs underground.

Here, in the electromagnetic induction type device as in the above configuration,
・ When a current of low frequency (for example, “10 kHz”) is passed, the search range (“magnetic field range”) can be expanded, but the search accuracy decreases (measurement error (noise, etc.) increases) On the other hand,
・ If a current of high frequency (for example, “80 kHz”) is passed, the search accuracy can be improved, but the search range is narrowed.
(Characteristics and disadvantages)

Then, in the above configuration, so as to take advantage of any of the advantages of these frequencies,
・ When the distance between the `` underground entry part '' and the `` embedding target '' is far away, while passing a low frequency current to the `` buried object '',
・ If these distances are close, a high-frequency current is sent to the “embedding target”.
This makes it possible to detect the existence of the “embedding target” with high accuracy while suppressing power consumption.

  In summary, according to the present invention having the above-described configuration, it is possible to detect the existence of an “embedding target” with higher accuracy while suppressing power consumption, and to be versatile. It is.

  In the invention relating to the metal exploration system, it is preferable that the frequency variable unit increases the frequency of the current as the degree of approach increases.

  In the invention relating to the metal exploration system, the underground working device controls the drive of the underground approach unit and the drive of the underground approach unit by the drive unit according to the degree of approach. And a drive control unit that performs the operation.

  In the invention related to the metal exploration system, as another configuration closely related to the above configuration, the metal exploration system has an underground entry portion capable of entering the ground, and allows the underground entry portion to enter the underground. A metal exploration system comprising: an underground working device that performs underground work; and a power feeding device that applies electric current to a buried object having conductivity embedded in the ground, wherein the underground entry portion And a magnetic field detector that detects a magnetic field generated in the object to be buried when the current is applied by the power feeding device, and an upper and lower position that calculates the vertical position of the underground approaching portion with respect to a predetermined reference height position. A power calculating device, and the power supply device includes a frequency variable unit configured to vary a frequency of the current applied to the burying target according to a vertical position of the underground approaching unit with respect to a predetermined reference height position. It can be configured.

  Similarly, in the invention related to the metal exploration method, as another configuration closely related to the above configuration, a current application step for applying a current to an embedded object having conductivity embedded in the ground, and an underground operation The underground approach portion is provided with a magnetic field generated in the burial target by performing an underground approach step in which the underground approach portion provided in the underground work device that performs the operation enters the ground and the current application step. A magnetic field detection step that is detected by a magnetic field detection unit, and a vertical position calculation step that calculates a vertical position of the underground approach portion with respect to a predetermined reference height position, wherein the current application step calculates the vertical position It may be configured to include a frequency variable step of varying the frequency of the current applied to the burying object in accordance with the vertical position calculated by performing the step.

  Also in the metal exploration system and the metal exploration method according to the other configurations described above, the frequency of the current applied to the “embedding target” can be changed according to the distance between the “embedding target” and the “underground entry portion”. Therefore, as in the above-described invention, it is possible to detect the presence of the “embedding target” with higher accuracy while suppressing power consumption, and to achieve high versatility.

  In the metal exploration system according to the other configuration, it is preferable that the frequency variable unit raises the frequency of the current as the vertical position becomes lower.

  In the metal exploration system according to the other configuration, the underground working device includes a drive unit that drives the underground entry unit, and driving of the underground entry unit by the drive unit according to the vertical position. And a drive control unit for controlling the motor.

  As described above, according to the metal exploration system and the metal exploration method according to the present invention, it is possible not only to detect the presence of an embedded object with higher accuracy while suppressing power consumption while having a simple configuration, It can be made versatile.

It is explanatory drawing for demonstrating the metal search system concerning this embodiment. It is a block diagram of the metal exploration system of FIG. It is a flowchart which shows the control processing of the metal search system of FIG. It is the schematic diagram which showed typically the magnetic field produced around a pipe line.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is an explanatory diagram for explaining a metal exploration system according to the present embodiment, FIG. 2 is a block diagram of the metal exploration system of FIG. 1, and FIG. 3 is a flowchart showing control processing of the metal exploration system of FIG. 4 is a schematic diagram schematically showing a magnetic field generated around a pipe line.

  FIG. 1 is a diagram illustrating a state in which a metal water pipe P buried in the ground is being searched using the metal searching system 1 according to the present embodiment. The metal exploration system 1 and the water pipe P correspond to the “metal exploration system” and the “embedding target” described in the claims, respectively.

  As shown in FIG. 1, the metal exploration system 1 according to the present embodiment includes an excavating machine 10 and a power feeding device 20. The excavating machine 10 and the power feeding device 20 correspond to the “underground work device” and the “power feeding device” described in the claims, respectively.

  The excavating machine 10 is a so-called shovel car, and is connected to a swivelable machine body 11 so as to be rotatable with respect to each other in the order of a plurality of booms 12A and 12B and a bucket 13 for scooping up earth and sand. The booms 12 </ b> A and 12 </ b> B and the bucket 13 correspond to the “underground entry part capable of entering the ground” recited in the claims.

  Since the excavating machine 10 itself is publicly known, a detailed description thereof is omitted, but also in the present embodiment, by controlling a drive unit (for example, a hydraulic circuit) 17 that switches an oil path that leads to the hydraulic cylinders 14A to 14C. (Refer FIG. 2), boom 12A, 12B and the bucket 13 are each comprised so that it may move to an up-down direction. The drive unit 17 corresponds to a “drive unit” recited in the claims.

  In the excavating machine 10 according to the present embodiment, the magnetic field detector 16 is attached to the inner outer surface of the boom 12B (on the front end side). The magnetic field detector 16 is a known magnetic sensor capable of detecting a magnetic field M generated around a water pipe P described later. The magnetic field detector 16 corresponds to a “magnetic field detector” recited in the claims.

  The power feeding device 20 is a device that generates a magnetic field M around a metal water pipe P to be searched, and together with the magnetic field detection unit 16 provided in the excavating machine 10, a so-called electromagnetic induction type searching device (electromagnetic induction). Type locator).

  In the present embodiment, an alternating current AC is passed through any two points of the buried water pipe P, and the magnetic field (alternating magnetic field) M generated thereby is detected by the magnetic field detector 16, thereby A so-called “two-point detection method” is used to obtain “position” and “embedding depth”.

  Specifically, in this embodiment, two exposed portions E1 and E2 of the output terminal T1 and the input terminal T2 of the power feeding device 20 and the buried water pipe P (in this embodiment, a joint portion of the water meter WM). And a flange portion of the valve V) are connected via cables C1 and C2, respectively, so that an alternating current AC having a predetermined frequency flows through the water pipe P.

  When an alternating current AC is passed through the water pipe P, a closed loop that flows in the order of one output terminal T1, cable C1, water pipe P, cable C2, and input terminal T2 is formed. A concentric magnetic field (alternating magnetic field) M is generated along the line.

In this state, the magnetic field M can be detected by scanning the magnetic field detection unit 16 above the water pipe P, and the “embedding position” and “embedding depth” of the water pipe P are determined based on the detected magnetic field M. It can be obtained based on the intensity of
Since the method for obtaining such “embedding position” and “embedding depth” is now known, detailed description thereof will be omitted. For example, for the “buried position”, the magnetic field detection unit 16 is moved in the horizontal direction. In addition, the “embedding depth” can be obtained by moving the magnetic field detector 16 in the vertical direction.

  In the present embodiment, the “embedding position” and “embedding depth” of the water pipe P are configured to be obtained using the “two-point detection method”, but it is also possible to obtain using the so-called “one-point detection method” It is. In this case, what is necessary is just to connect the output terminal T1 of the electric power feeder 20 and the arbitrary one points of the water pipe P, for example, the joint part of the water supply meter WM, via the cable C1.

  Next, the electrical configuration of the excavating machine 10 and the power feeding device 20 constituting the metal exploration system 1 will be described with reference to FIGS. 1 and 2.

First, the excavating machine 10 will be described.
As shown in FIGS. 1 and 2, the excavating machine 10 includes a control unit 15, the magnetic field detection unit 16 described above, a drive unit 17, a notification unit 18, and a communication unit 19. The control unit 15 corresponds to an “approach degree calculation unit” and a “drive control unit” described in the claims.

The control unit 15 is electrically connected to the magnetic field detection unit 16, the drive unit 17, the notification unit 18, and the communication unit 19.
The control unit 15 is a device that controls the operation of the entire excavating machine 10 including the driving unit 17 and includes, for example, a central processing unit (CPU) and a storage device.

As will be described in detail later, when the control unit 15 determines that the water pipe P is buried below the excavation position,
-Based on the intensity of the magnetic field M detected by the magnetic field detection unit 16, the distance between the magnetic field detection unit 16 and the water pipe P is calculated.
In accordance with the calculated distance, a “frequency setting signal” for changing the frequency of the alternating current AC applied to the water pipe P is transmitted to the power supply device 20 and the hydraulic cylinders 14A to 14C by the drive unit 17 Limit the driving of the
Control such as.

  The storage unit of the control unit 15 obtains the distance between the magnetic field detection unit 16 and the water pipe P based on the basic information that governs the basic operation of the excavating machine 10 and the magnetic field M detected by the magnetic field detection unit 16. Is stored, and “distance information” relating to the distance between the magnetic field detector 16 and the water pipe P is stored.

Speaking specifically about this "distance information", the storage device
“First safety distance information” (for example, “3.5 m” or more, hereinafter, “1st safety distance”) for setting the frequency of the alternating current AC to “first frequency” (for example, “10 kHz”). ”),
“Second safe distance information” (for example, “2.5 m” or more and less than “3.5 m”, hereinafter, this distance) for setting the frequency of the alternating current AC to the “second frequency” (for example, “30 kHz”). Is referred to as the “second safe distance”),
“Third safety distance information” (for example, “1.5 m” or more and less than “2.5 m”, hereinafter, this distance) for setting the frequency of the alternating current AC to “third frequency” (for example, “80 kHz”) Is referred to as the “third safety distance”), and
"Drive limit distance information" for limiting the drive of the hydraulic cylinders 14A to 14C by the drive unit 17 (for example, less than "1.5 m", hereinafter, this distance is referred to as "drive limit distance");
Etc. are stored.

When the control unit 15 determines that the distance between the magnetic field detection unit 16 and the water pipe P is the “first safety distance”, the “second safety distance”, or the “third safety distance”, information indicating that Is transmitted to the power feeding device 20 and is output to the drive unit 17 and the notification unit 18.
On the other hand, when the control unit 15 determines that the distance between the magnetic field detection unit 16 and the water pipe P is the “drive stop distance”, the control unit 15 outputs information indicating that to the drive unit 17 and the notification unit 18. To do.

As will be described in detail later, the controller 15 determines “first frequency setting signal” when it is determined as “first safety distance”, and “second frequency setting signal” when it is determined as “second safety distance”. When it is determined that the distance is “third safety distance”, a “third frequency setting signal” is transmitted to the power feeding device 20 and a predetermined “notification signal” (for example, an audio signal or The image signal is controlled to be output to the notification unit 18.
As a result, in the power feeding device 20, an alternating current AC having a frequency corresponding to each “frequency setting signal” is applied to the water pipe P. On the notification unit 18, for example, a speaker is used depending on the distance. If the display device is a display device, the distance or the like is displayed (for example, the sound is sounded so that the interval becomes shorter as the “distance” becomes shorter).

Further, when the control unit 15 determines that it is the “drive limit distance”, the “drive limit signal” and the “notification signal” indicating that the “drive limit distance” has been reached, respectively, , Control to output to the notification unit 18 is performed.
Thereby, in the drive part 17, in order to prevent the bucket 13 from moving below the position, the drive of the hydraulic cylinders 14A to 14C is limited, while the notifying part 18 indicates that the state is present. Notification will be made.
The reason why the driving of the hydraulic cylinders 14A to 14C is limited is that the possibility that the water pipe P is broken or damaged (hereinafter referred to as “damage or the like”) when the bucket 13 moves downward from the position is increased. Because. In this state, the bucket 13 does not have to move “unnecessarily” below its position, so there is no need to limit the upward movement of the bucket 13, and the downward movement If the work can be performed safely, it is not necessarily prohibited. In this case, for example, the moving speed of the bucket below can be made slower than usual.

  The notification unit 18 enters the state when the distance between the magnetic field detection unit 16 and the water pipe P is “first safety distance” to “third safety distance” and “drive stop distance”. It is an apparatus for informing the operator that the vehicle is in operation, and is configured to be operated based on a signal output from the control unit 15. Note that such a notification unit 18 can be realized by providing the above-described speaker, display device, or the like, for example, in the cockpit of the body 11 or the like.

  The communication unit 19 is an interface capable of performing wireless communication or wired communication with the power supply device 20 and is used for transmitting and receiving various types of information.

Next, the power feeding device 20 will be described.
As illustrated in FIG. 2, the power feeding device 20 includes a control unit 21, a frequency variable unit 22, and a communication unit 23. The frequency variable unit 22 corresponds to a “frequency variable unit” recited in the claims.

For example, the control unit 21 includes a microcomputer equipped with a central processing unit, a storage device, and the like, and is electrically connected to the frequency variable unit 22 and the communication unit 23.
In the present embodiment, the control unit 21 mainly determines the frequency of the alternating current AC to be applied to the water pipe P based on “first frequency setting signal” to “third frequency setting signal” transmitted from the excavating machine 10. Control to set (change).

The storage device of the control unit 21 stores basic information that governs the basic operation of the power supply device 20, and stores “frequency information” related to the frequency of the alternating current AC applied to the water pipe P.
Speaking specifically about this "frequency information", the storage device
“First frequency information” (for example, “10 kHz”, which will be referred to as “first frequency” hereinafter) set when the “first frequency setting signal” is received,
"Second frequency information" set when receiving the "second frequency setting signal" (for example, "30 kHz", hereinafter, this frequency is referred to as "second frequency"),
“Third frequency information” (for example, “80 kHz”, hereinafter referred to as “third frequency”) set when the “third frequency setting signal” is received, and
“Initial frequency information (default frequency information)” (for example, “10 kHz”, hereinafter referred to as “default frequency”) when the AC current AC is first applied to the exploration target (water pipe P),
Etc. are stored.

  The frequency variable unit 22 is a circuit for varying the frequency of the alternating current AC applied to the water pipe P, and can be configured using a known frequency conversion circuit (for example, an inverter). The frequency variable unit 22 has one end connected to a 100V or 200V AC power supply (commercial power supply) or the like, and the other end connected to the output terminal T1 and the input terminal T2. As described above, the output terminal T1 and the input terminal T2 are connected to predetermined locations (exposed portions E1, E2) of the water pipe P via the cable C1 and the cable C2 (FIG. 1). reference).

  The communication unit 23 is an interface that has the same configuration as the communication unit 19 of the excavating machine 10 and can perform wired or wireless communication with the communication unit 19.

Next, control processing (metal exploration method) performed by the control unit 15 of the excavating machine 10 will be described with reference to FIGS.
In this control process, the excavating machine 10 and the power feeding device 20 are in a state where they can communicate with each other, and an AC current AC of “default frequency” is applied to the search target (in this embodiment, “water pipe P”). It is configured to be executed on condition that it is applied. The operation of applying the alternating current AC to the “water pipe P” corresponds to the “current application step” recited in the claims.

(Step S101)
As shown in FIG. 3, the control unit 15 of the excavating machine 10 first determines whether or not the excavation operation is being performed in step S <b> 101.
Specifically, the control unit 15 determines whether or not the drive unit 17 that operates the booms 12A and 12B and the bucket 13 is driven.
If the control unit 15 determines that the drive unit 17 is driven, the process proceeds to step S102. If the control unit 15 determines that the drive unit 17 is not driven, the control process ends. In addition, the operation | movement which makes the said bucket 13 etc. approach into the ground corresponds to the "underground approach process" as described in a claim.

(Step S102)
In step S <b> 102, the control unit 15 determines whether or not the magnetic field M generated around the water pipe P is detected by the magnetic field detection unit 16. In the present embodiment, as described above, the AC current AC having a predetermined frequency (“first frequency” to “third frequency” and “default frequency”) is supplied to the water pipe P in a state where the control process is performed. Therefore, if excavation work is performed at a location “upper periphery” of the water pipe P, the magnetic field detection unit 16 detects the magnetic field M.
If the control unit 15 determines that the magnetic field M is detected by the magnetic field detection unit 16, the control unit 15 proceeds to step S103. If the control unit 15 determines that the magnetic field M is not detected, the control unit 15 ends this control processing. The operation of detecting the magnetic field M generated around the water pipe P by the magnetic field detection unit 16 corresponds to the “magnetic field detection step” described in the claims.

(Step S103)
In step S103, the control unit 15 determines whether or not the water pipe P is buried below the excavation position. Such determination is performed by a known technique for obtaining the “embedding position” (for example, the peak value of the magnetic field M detected when the magnetic field detector 16 is moved in the horizontal direction (the body 11 is turned in the left-right direction)). This method can be realized by appropriately adopting a method obtained based on the above.
If the control unit 15 determines that the water pipe P is buried below the excavation position, the control unit 15 proceeds to step S104. If the control unit 15 determines that the water pipe P is not buried, this control process ends. In addition, when it is clear that the water pipe P is not buried below the excavation position (for example, when this is clear even if it is explored by other exploration devices such as electromagnetic induction type locators), the power feeding device The application of the alternating current AC by 20 may be stopped (determined as “No” in step S102 and step S103). In this way, useless power consumption can be prevented.

(Step S104)
In step S104, the control unit 15 performs a process of calculating the distance from the magnetic field detection unit 16 to the water pipe P. Such determination is performed by a known technique for obtaining the “embedding depth” (for example, the intensity of the magnetic field M that is displaced when the magnetic field detector 16 is moved in the vertical direction (the booms 12A and 12B are moved in the vertical direction) This can be realized by appropriately adopting a method of calculating based on the above.
The control unit 15 calculates the distance between the magnetic field detection unit 16 and the water pipe P, and then moves the process to step S105. In addition, the process of step S104 by the said control part 15 corresponds to the "approach degree calculation process" as described in a claim.

(Step S105)
In step S105, the control unit 15 determines whether or not the distance calculated in the process of step S104 is equal to or greater than a “first safety distance” (for example, “3.5 m”).
If the control unit 15 determines that the distance between the magnetic field detection unit 16 and the water pipe P is the “first safety distance”, the control unit 15 moves the process to step S106, and these distances are not the “first safety distance”. If determined, the process proceeds to step S107.

(Step S106)
In step S <b> 106, the control unit 15 transmits a “first frequency setting signal” to the power feeding device 20 and indicates that the distance between the magnetic field detection unit 16 and the water pipe P is the “first safety distance”. Control to output the “notification signal” to the notification unit 18 is performed.
Thereby, in the control part 21 of the electric power feeder 20, while controlling the alternating current AC of "1st frequency" (for example, "10kHz") to the water pipe P (magnetic field "M1" of FIG. 4) In the notification unit 18, notification indicating the “first safety distance” is performed.
The control unit 15 transmits the “first frequency setting signal” to the power supply apparatus 20 and performs control to output a predetermined “notification signal” to the notification unit 18, and then ends this control process. In addition, the process of the said step S106 by the control part 15, the process of step S108 mentioned later, and the process of step S110 correspond to the "frequency variable process" as described in a claim.

(Step S107)
In step S107, the control unit 15 determines whether or not the distance calculated in the process of step S104 is equal to or greater than a “second safety distance” (for example, “2.5 m”).
When the control unit 15 determines that the distance between the magnetic field detection unit 16 and the water pipe P is the “second safety distance”, the control unit 15 moves the process to step S108, and the distance between them is the “second safety distance”. If not, the process moves to step S109.

(Step S108)
In step S <b> 108, the control unit 15 transmits a “second frequency setting signal” to the power feeding device 20 and indicates that the distance between the magnetic field detection unit 16 and the water pipe P is the “second safety distance”. Control to output the “notification signal” to the notification unit 18 is performed.
Thereby, in the control part 21 of the electric power feeder 20, while controlling the alternating current AC of a "2nd frequency" (for example, "30 kHz") to the water pipe P (magnetic field "M2" of FIG. 4) In the notification unit 18, notification indicating the “second safety distance” is performed.
The control unit 15 transmits the “second frequency setting signal” to the power supply apparatus 20 and performs control to output a predetermined “notification signal” to the notification unit 18, and then ends the present control process.

(Step S109)
In step S109, the control unit 15 determines whether or not the distance calculated in the process of step S104 is a “third safety distance” (for example, “1.5 m” or more and less than “2.5 m”).
When the control unit 15 determines that the distance between the magnetic field detection unit 16 and the water pipe P is the “third safety distance”, the control unit 15 moves the process to step S110, and the distance between these is the “third safety distance”. If not, the process moves to step S111.

(Step S110)
In step S110, the control unit 15 transmits a “third frequency setting signal” to the power feeding device 20, and indicates that the distance between the magnetic field detection unit 16 and the water pipe P is the “third safety distance”. Control to output the “notification signal” to the notification unit 18 is performed.
Thereby, in the control part 21 of the electric power feeder 20, while controlling the alternating current AC of "3rd frequency" (for example, "80 kHz") to the water pipe P (magnetic field "M3" of FIG. 4) In the notification unit 18, notification indicating the “third safety distance” is performed.
The control unit 15 transmits the “third frequency setting signal” to the power supply apparatus 20 and performs control to output a predetermined “notification signal” to the notification unit 18, and then ends the present control process.

(Step S111)
In step S111, the control unit 15 transmits a “drive limit signal” and a “notification signal” indicating that the distance between the magnetic field detection unit 16 and the water pipe P has reached the “drive limit distance”. Control to output to the drive part 17 and the alerting | reporting part 18 is performed.
In this control process, the distance between the magnetic field detector 16 and the water pipe P in the process of step S109 is “third safety distance” (for example, “1.5 m” or more and less than “2.5 m”). If it is determined that it is not, that is, when the “driving limit distance” (for example, less than “1.5 m”) has been reached, this is performed.
Thereby, in the drive part 17, while restrict | limiting the drive of hydraulic cylinder 14A-14C so that the bucket 13 may not move below the position, the alerting | reporting part 18 alert | reports that it is the state. Will be done.

As described above, in this embodiment,
(A) Applying an alternating current AC to the water pipe P so that the magnetic field M generated around the water pipe P can be detected by the magnetic field detector 16 provided on the boom 12B on the tip side of the excavating machine 10.
(B) Let the bucket 13 or the like enter the ground,
(C) As the distance between the magnetic field detector 16 and the water pipe P approaches, the frequency of the alternating current AC applied to the water pipe P is set to “first frequency” (for example, “10 kHz”) → “Second frequency” (for example, “30 kHz”) → “third frequency” (for example, “80 kHz”)
(D) When the distance between the magnetic field detection unit 16 and the water pipe P reaches a “driving limit distance” (for example, less than “1.5 m”), the downward movement of the bucket 13 is limited.
It is configured as follows.

  That is, in this embodiment, since the magnetic field M generated around the water pipe P can be detected by the magnetic field detection unit 16 of the excavating machine 10, the presence of the water pipe P can be confirmed with relatively high accuracy. Is possible. In this regard, in this embodiment, it can be said that it is possible to effectively prevent the water pipe P from being damaged during excavation work by the excavating machine 10.

Moreover, in this embodiment, with respect to the water pipe P,
・ When the distance between the magnetic field detector 16 and the water pipe P is long, the search accuracy is reduced due to noise or the like, but the magnetic field M having a wide range (see the magnetic field “M1” in FIG. 4) is generated. While applying an alternating current AC of “one frequency” (eg, “10 kHz”),
When these distances are close, the range becomes narrow, but the AC of the “third frequency” (for example, “80 kHz”) that generates a magnetic field M (see magnetic field “M3” in FIG. 4) with high exploration accuracy. Apply current AC,
Therefore, it is possible to detect the presence of the water pipe P with high accuracy while suppressing power consumption.

  Furthermore, in this embodiment, when the distance between the magnetic field detector 16 and the water pipe P reaches a “drive limit distance” (for example, less than “1.5 m”), the downward movement of the bucket 13 is limited. Since it is comprised so that damage to the water pipe P etc. can be prevented reliably.

  In this embodiment, the AC current AC was applied to the metal water pipe P and the exploration was performed. However, the technology (the present invention) of the present embodiment can be applied to any “embedding target” having conductivity. It is possible to apply. In this respect, the present invention can be said to be excellent in versatility.

  In the present embodiment, the frequency of the alternating current AC applied to the water pipe P is configured to change “stepwise” in accordance with the distance between the magnetic field detector 16 and the water pipe P (“ First frequency ”→“ second frequency ”→“ third frequency ”), and it is also possible to change“ continuously ”according to these distances.

  Furthermore, in the present embodiment (hereinafter referred to as “first embodiment”), the frequency of the alternating current AC applied to the water pipe P is changed according to the distance between the magnetic field detector 16 and the water pipe P. Although comprised as mentioned above, it is also possible to change according to the approach amount of the bucket 13 with respect to the ground. In addition, such an approach amount can be calculated | required by calculating based on each expansion-contraction amount etc. of hydraulic cylinder 14A-14C, for example.

  In this case, as in the first embodiment, for example, the frequency of the alternating current AC applied to the water pipe P is “stepwise” as the amount of entry of the bucket 13 into the ground increases (decreases). Alternatively, it may be increased (decreased) “continuously”. The height of the “ground” corresponds to the “reference height position” described in the claims. Further, the control device (for example, the control unit 15) for determining the amount of the bucket 13 entering the ground and the process correspond to the “vertical position calculating unit” and the “vertical position calculating step” described in the claims, respectively. To do.

More specifically, for example, if it is found that a water pipe P having a buried depth of “5 m” is buried in the vicinity of the construction site by an inquiry to a water company, the above-described modified example (hereinafter referred to as the following modification example) , Referred to as “second embodiment”)
When the amount of approach of the bucket 13 to the ground is less than “1.5 m”, an alternating current AC of “first frequency” (for example, “10 kHz”) is
When the amount of approach of the bucket 13 to the ground is “1.5 m” or more and less than “2.5 m”, an alternating current AC of “second frequency” (for example, “30 kHz”) is
When the amount of approach of the bucket 13 to the ground is “2.5 m” or more and less than “3.5 m”, an alternating current AC of “third frequency” (for example, “80 kHz”) is
Such information may be stored in the storage device of the control unit 21 so as to be applied to the water pipe P.

  In addition, since the burial depth obtained by the above inquiry is a value that is likely to fluctuate depending on the situation of the construction site (for example, the burial status of other burial pipes), The burial depth is generally "large" and "5 m"). For this reason, when setting a frequency based on the approach amount of the bucket 13 with respect to the ground as in the second embodiment, the above-described example (the approach amount of the bucket 13 with respect to the ground is “2.5 m” or more and “3.5 m”). It can be said that it is desirable to carry out after considering a safe value for the embedding depth by the inquiry, such as applying “third frequency” to the water pipe P when it is less than “”.

Thus, in the second embodiment, as in the first embodiment,
・ When the distance between the magnetic field detector 16 and the water pipe P is long, the search accuracy decreases, but the “first frequency” AC current AC that generates a wide magnetic field M around the water pipe P (See magnetic field “M1” in FIG. 4),
When these distances are close, an AC current AC of “third frequency” that generates a magnetic field M with high search accuracy is applied (see magnetic field “M3” in FIG. 4).
It is possible.

  In this regard, in the second embodiment, the amount of penetration of the bucket 13 with respect to the ground is predicted based on the prediction that the water pipe P will be buried in this depth (in the above example, “5 m”). The frequency of the alternating current AC applied to the water pipe P is changed according to the above. However, as in the first embodiment, the magnetic field detector 16 attached to the bucket 13 causes the water pipe P to It can be said that the presence can be detected with high accuracy (see FIG. 4 and the like).

  Also in the second embodiment, similarly to the first embodiment, when the amount of the bucket 13 entering the ground reaches a predetermined value (in the above example, for example, the amount of the bucket 13 entering the ground is “3”). .5 m ”or more), it is possible to limit the drive of the hydraulic cylinders 14A to 14C so that the bucket 13 does not move below the position.

Of course, the control for restricting the drive of the hydraulic cylinders 14A to 14C is not limited to the control based on the amount of the bucket 13 entering the ground, and the magnetic field detection unit 16 and the water pipe P as in the first embodiment. It is also possible to control according to the distance between.
The control in this case will be described according to the above example. For example, the amount of entry of the bucket 13 with respect to the ground becomes “2.5 m” or more and less than “3.5 m”, and the “third frequency” AC is supplied to the water pipe P After applying the current AC, when the distance between the magnetic field detector 16 and the water pipe P reaches a “drive limit distance” (for example, less than “1.5 m”), the hydraulic cylinders 14A to 14C are driven. Control to be limited may be performed.

In addition to performing such control, for example, the amount of penetration of the bucket 13 with respect to the ground becomes “1.5 m” or more and less than “2.5 m”, and the AC current AC of “second frequency” is applied to the water pipe P. After that, it is possible to perform the same control as in the first embodiment.
In this case, for example, after applying the “second frequency” AC current AC to the water pipe P based on the amount of the bucket 13 entering the ground, the distance between the magnetic field detector 16 and the water pipe P is:
When the “third drive limit distance” (for example, “1.5 m” or more and less than “2.5 m”) is reached, an AC current AC of “third frequency” (for example, “80 kHz”) is applied to the water pipe P. on the other hand,
When the “driving limit distance” (for example, less than “1.5 m”) is reached, control for limiting the driving of the hydraulic cylinders 14A to 14C may be performed.

  In the first embodiment and the second embodiment, the magnetic field detection unit 16 is attached to the inner outer surface of the boom 12B (on the front end side), but can be attached to other places, for example, the bucket 13. . In this case, the magnetic field detector 16 may be embedded in a predetermined position (for example, a blade edge) of the bucket 13 from the viewpoint of preventing damage.

  Moreover, in the said 1st Embodiment and 2nd Embodiment, although what was called a shovel car (excavation machine 10) was illustrated as an example of an underground working apparatus, even if it is another excavation machine (for example, what is called a boring machine). Well, it may be a hand-held type, for example, a so-called exploration rod or scoop that pierces into the ground and explores underground objects.

  As mentioned above, although embodiment which applied the invention made by this inventor was described, this invention is not limited by the description and drawing which make a part of indication of this invention by this embodiment. That is, it is added that other embodiments, examples, operation techniques, and the like made by those skilled in the art based on this embodiment are all included in the scope of the present invention.

DESCRIPTION OF SYMBOLS 1 Metal exploration system 10 Excavation machine 11 Airframe 12A, 12B Boom 13 Bucket 14A-14C Hydraulic cylinder 15 Control part 16 Magnetic field detection part 17 Drive part 18 Notification part 19 Communication part 20 Power supply apparatus 21 Control part 22 Frequency variable part 23 Communication part AC AC current M, M1-M3 Magnetic field P Water pipe WM Water meter V Valve E1, E2 Exposed portion T1 Output terminal T2 Input terminal C1, C2 Cable

Claims (8)

An underground working device that has an underground entry part that can enter the underground, and performs underground work by causing the underground entry part to enter the underground,
A metal exploration system comprising: a power feeding device that applies current to a buried object having conductivity buried in the ground,
A magnetic field detection unit that is provided in the underground entry unit and detects a magnetic field generated in the burying target when a current is applied by the power feeding device;
An approach degree calculation unit that calculates an approach degree of the underground approach part with respect to the buried object based on the magnetic field detected by the magnetic field detection part,
The power supply device
A frequency variable unit that varies the frequency of the current applied to the embedment target according to the approach degree calculated by the approach degree calculation unit;
A metal exploration system characterized by this.   The metal exploration system according to claim 1, wherein the frequency variable unit increases the frequency of the current as the degree of approach increases. The underground working device is:
A drive unit for driving the underground approach unit;
The metal exploration system according to claim 1, further comprising: a drive control unit that controls driving of the underground approaching unit by the driving unit according to the degree of approach. An underground working device that has an underground entry part that can enter the underground, and performs underground work by causing the underground entry part to enter the underground,
A metal exploration system comprising: a power feeding device that applies current to a buried object having conductivity buried in the ground,
A magnetic field detection unit that is provided in the underground approach portion and detects a magnetic field generated in the burying target when the current is applied by the power feeding device;
A vertical position calculation unit that calculates the vertical position of the underground approach portion with respect to a predetermined reference height position,
The power supply device
A frequency variable unit that varies the frequency of the current applied to the object to be buried in accordance with the vertical position of the underground approach portion with respect to a predetermined reference height position;
A metal exploration system characterized by this.   The metal exploration system according to claim 4, wherein the frequency variable unit increases the frequency of the current as the vertical position becomes lower. The underground working device is:
A drive unit for driving the underground approach unit;
6. The metal exploration system according to claim 4, further comprising: a drive control unit that controls driving of the underground approach unit by the drive unit according to the vertical position. A current applying process for applying a current to a buried object having conductivity embedded in the ground;
Underground approach process of entering the underground approach portion provided in the underground work device that performs underground work into the ground,
A magnetic field detection step of detecting a magnetic field generated in the buried object by performing the current application step with a magnetic field detection unit provided in the underground approach portion;
An approach degree calculating step for calculating an approach degree of the underground approach portion with respect to the buried object based on the magnetic field detected by performing the magnetic field detecting step,
The current application process includes:
Including a frequency variable step of varying the frequency of the current applied to the object to be buried in accordance with the approach degree calculated by performing the approach degree calculating step.
A metal exploration method characterized by that. A current applying process for applying a current to a buried object having conductivity embedded in the ground;
Underground approach process of entering the underground approach portion provided in the underground work device that performs underground work into the ground,
A magnetic field detection step of detecting a magnetic field generated in the buried object by performing the current application step with a magnetic field detection unit provided in the underground approach portion;
A vertical position calculating step for calculating the vertical position of the underground approach portion with respect to a predetermined reference height position,
The current application process includes:
Including a frequency variable step of varying a frequency of the current applied to the object to be embedded according to the vertical position calculated by performing the vertical position calculation step.
A metal exploration method characterized by that.