JP6994431B2 - Metal exploration system and metal exploration method - Google Patents

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 existence of a long metal object (for example, a metal tube) buried in the ground. Is.

Conventionally, when excavating a road or the like using an excavator (for example, a shovel car), it is necessary to confirm the burial status of the buried pipe laid near the construction site with a management company such as a gas company in advance. , Exploration of buried pipes is carried out using exploration equipment to prevent damage to the buried pipes.

However, even if such work is performed in advance, there are many cases where the position of the buried pipe to be actually buried is different, or an unexpected buried pipe is buried. There was a risk that the buried pipe would be damaged or damaged during the excavation work.

Therefore, in order to solve such a problem, for example, a technique as described in Patent Document 1 has been proposed.
The technique of Patent Document 1 is
(A) A transponder in which predetermined information is stored is fixed to a pipe in advance and buried.
(B) After that, when excavating the ground, the presence of the buried pipe is detected by issuing a call signal from the transmission / reception device attached to the excavation machine and receiving the response signal from the transponder.
It is configured as follows.

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

Japanese Unexamined Patent Publication No. 07-317107

However, in the technique of Patent Document 1, when the pipe is buried in the ground, the transponder must be fixed in advance, so that it is practically difficult to oblige all the pipes to be buried. rice field.

In this respect, it cannot be said that the technique of Patent Document 1 greatly contributes from the viewpoint of preventing damage / damage of the buried pipe, but there is 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 one formed by the "metal member" occupies most of them.
Based on this situation, it is extremely important to perform excavation work while grasping the position of the buried pipe made of "metal member".

The present invention has been made to solve such a problem, and to provide a metal exploration system and a metal exploration method which are highly versatile and can accurately detect the burial position of a buried pipe. be.

According to the metal exploration system according to the present invention, the above-mentioned problem has an underground approach portion that can enter into the ground, and the underground approach portion is made to enter the ground to perform underground work. A metal exploration system including a working device and a power feeding device for applying an electric current to a conductive buried object buried in the ground. The degree of approach that calculates the degree of approach of the underground approaching portion to the buried object based on the magnetic field detected by the magnetic field detecting unit and the magnetic field detecting unit that detects the magnetic field generated in the buried object by applying. It is solved by having a calculation unit and a frequency variable unit that varies the frequency of the current applied to the buried object according to the proximity degree calculated by the proximity degree calculation unit. To.

Similarly, according to the metal exploration method according to the present invention, the above-mentioned problems are applied to a current applying process for applying an electric current to a conductive buried object buried in the ground and an underground working device for performing the underground work. The magnetic field generated in the buried object by performing the underground approach step of allowing the provided underground approach portion to enter the ground and the current application step is detected by the magnetic field detection unit provided in the underground entry portion. The current application step comprises a magnetic field detection step and an approach degree calculation step of calculating the approach degree of the underground approach portion to the buried object based on the magnetic field detected by performing the magnetic field detection step. It can also be solved by including a frequency variable step of varying the frequency of the current applied to the buried object according to the approach degree calculated by performing the approach degree calculation step.

The term "underground work equipment" here is a concept that includes all kinds of equipment that can be used to perform underground work, such as excavators for excavating soil and forming holes in the ground. In addition to machines such as boring machines, it means to include hand-held machines such as so-called exploration rods and shovels that pierce the ground and search for buried objects in the ground.

Further, the above-mentioned "underground entry part" is, for example, a bucket for scooping earth and sand in the case of a shovel car, a part for entering the ground in the case of an exploration rod, and earth and sand in the case of a scoop. The scooping part corresponds to each.

Further, the above-mentioned "object to be buried" is a concept including all kinds of conductive members capable of passing an electric current, and a typical example thereof is a pipe made of a metal member (for example, a gas pipe and a water and sewage pipe). Can be mentioned.

In the above configuration,
(A) An electric current is applied to the "buried object" so that the "magnetic field" generated around it can be detected by the "magnetic field detection unit" provided in the "underground entry portion".
(B) Let the "underground approach" enter the ground,
(C) Calculate the degree of approach of the "underground approach" to the "buried object",
(D) The frequency of the current applied to the "buried object" is changed according to the degree of proximity of the "underground approach" to the "buried object".
It is configured as follows.

That is, in the above configuration, the "magnetic field" generated around the "buried object" can be detected by the "magnetic field detection unit" provided in the "underground approaching part", so that the "buried object" can be detected with relatively high accuracy. It is possible to confirm the existence of. 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 "buried object" can be explored as long as it can pass an electric current, so that it can be made highly versatile.

Further, in the above configuration, the frequency of the current applied to the "buried object" is changed as the "underground approaching portion" enters the ground.

Here, in the electromagnetic induction type device as described above, the "buried object" is opposed to the "buried object".
-When a current with a low frequency (for example, "10 kHz") is applied, the exploration range ("magnetic field range") can be expanded, but the exploration accuracy decreases (measurement error (noise, etc.) increases). On the other hand
-When a high frequency (for example, "80 kHz") current is applied, the exploration accuracy can be improved, but the exploration range is narrowed.
It has such characteristics (merits and demerits).

Then, in the above configuration, in order to take advantage of any of these frequencies,
・ When the distance between the "underground approach" and the "buried object" is large, a low frequency current is passed through the "buried object", while
・ When these distances are short, a high frequency current is passed through the "burial target".
This makes it possible to detect the existence of the "buried object" with high accuracy while suppressing power consumption.

Summarizing these, according to the present invention provided with the above configuration, it is possible to detect the existence of the "buried object" with higher accuracy while suppressing power consumption, and it is possible to make it highly versatile. Is.

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

Further, in the invention relating to the metal exploration system, the underground work apparatus controls the driving unit for driving the underground approaching portion and the driving of the underground approaching portion by the driving unit according to the degree of approach. It is preferable to have a drive control unit and a drive control unit.

In the invention relating to the metal exploration system, as another configuration closely related to the above configuration, an underground approach portion capable of entering the ground is provided, and the underground entry portion is allowed to enter the ground. A metal exploration system including an underground work device for performing underground work and a power supply device for applying an electric current to a conductive buried object buried in the ground, wherein the underground approach portion is provided. A magnetic field detection unit that detects a magnetic field generated in the buried object when the current is applied by the power feeding device, and an upper and lower position that calculates the vertical position of the underground approach portion with respect to a predetermined reference height position. The power feeding device includes a position calculation unit, and has a frequency variable unit that changes the frequency of the current applied to the buried object according to the vertical position of the underground approach unit with respect to a predetermined reference height position. , Can be configured as such.

Similarly, in the invention relating to the metal exploration method, as other configurations closely related to the above configuration, a current applying process for applying an electric current to a conductive buried object buried in the ground and an underground work are performed. The underground approaching portion is provided with a magnetic field generated in the buried object by performing the underground approaching step of allowing the underground approaching portion provided in the underground work device to enter the ground and the current applying step. The current applying step includes the vertical position calculation step of calculating the vertical position of the underground approaching portion with respect to a predetermined reference height position, and the current applying step includes the vertical position calculation. It can also be configured to include a frequency variable step of varying the frequency of the current applied to the buried object according to the vertical position calculated by performing the step.

Also in the metal exploration system and metal exploration method related to the above other configurations, the frequency of the current applied to the "buried object" can be changed according to the distance between the "buried object" and the "underground approaching part". Therefore, as in the above-mentioned invention, the existence of the "buried object" can be detected with higher accuracy while suppressing the power consumption, and the versatility can be improved.

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

Further, in the metal exploration system according to the other configuration, the underground work apparatus has a drive unit for driving the underground approach portion and a drive unit for driving the underground approach portion according to the vertical position. It is preferable to have a drive control unit for controlling the above.

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 existence of the buried object with higher accuracy while suppressing the power consumption while having a simple configuration. It can be versatile.

It is explanatory drawing for demonstrating the metal exploration system which concerns on this embodiment. It is a block diagram of the metal exploration system of FIG. It is a flow chart which shows the control process of the metal exploration system of FIG. It is a schematic diagram which shows typically the magnetic field generated around a pipeline.

Hereinafter, one embodiment of the present invention will be described with reference to the drawings. 1 is an explanatory diagram for explaining the 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 flow diagram and a diagram showing a control process of the metal exploration system of FIG. 4 is a schematic diagram schematically showing the magnetic field generated around the pipeline.

FIG. 1 is a diagram showing a state of exploring a metal water pipe P buried in the ground by using the metal exploration 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 "burial target" described in the claims, respectively.

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

The excavator 10 is a so-called excavator car, and is rotatably connected to a swivel body 11 in the order of a plurality of booms 12A, 12B and a bucket 13 for scooping earth and sand. The booms 12A and 12B and the bucket 13 correspond to the "underground approach portion capable of entering the ground" described in the claims.

Since the excavation machine 10 itself is known, detailed description thereof will be omitted, but also in the present embodiment, by controlling the drive unit (for example, the hydraulic circuit) 17 for switching the oil passages leading to the hydraulic cylinders 14A to 14C. (See FIG. 2), the booms 12A and 12B, and the bucket 13 are configured to be moved in the vertical direction, respectively. The drive unit 17 corresponds to the "drive unit" described in the claims.

In the excavation machine 10 according to the present embodiment, the magnetic field detection unit 16 is attached to the inner outer surface of the boom 12B (on the tip side). The magnetic field detection unit 16 is a known magnetic sensor capable of detecting a magnetic field M generated around a water pipe P, which will be described later. The magnetic field detection unit 16 corresponds to the "magnetic field detection unit" described 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 explored, and is a so-called electromagnetic induction type exploration device (electromagnetic induction) together with a magnetic field detection unit 16 provided in the excavation machine 10. Type locator).

In the present embodiment, an alternating current AC is passed through arbitrary two points of the buried water pipe P, and the magnetic field (AC magnetic field) M generated by the alternating current AC is detected by the magnetic field detection unit 16 to "buried" the water pipe P. The so-called "two-point detection method" that obtains the "position" and "burial depth" is adopted.

Specifically, in the present embodiment, the output terminal T1 and the input terminal T2 of the power feeding device 20 and the two exposed portions E1 and E2 of the embedded water pipe P (in the present embodiment, the joint portion of the water supply meter WM). And the 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 is formed in which one of the output terminals T1, the cable C1, the water pipe P, the cable C2, and the input terminal T2 flows in this order. Along the line, a concentric magnetic field (alternating current) M is generated.

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 "buried position" and "buried depth" of the water pipe P are the detected magnetic field M. It is possible to obtain it based on the strength of the water pipe.
Since the method for obtaining such "buried position" and "buried 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. Therefore, the "buried depth" can be obtained by moving the magnetic field detection unit 16 in the vertical direction.

In this embodiment, the "buried position" and "buried depth" of the water pipe P are configured to be obtained by using the "two-point detection method", but it is also possible to obtain the "one-point detection method". Is. In this case, the output terminal T1 of the power feeding device 20 and any one point of the water pipe P, for example, the joint portion of the water supply meter WM may be connected via the cable C1.

Next, the electrical configurations of the excavation 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 excavation machine 10 will be described.
As shown in FIGS. 1 and 2, the excavation machine 10 has a control unit 15, a 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 the "approach degree calculation unit" and the "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 excavation machine 10 including the drive unit 17, and has, for example, a central processing unit (CPU: Central Processing Unit), a storage device, and the like.

As will be described in detail later, when the control unit 15 determines that the water pipe P is buried below the excavation position,
The distance between the magnetic field detection unit 16 and the water pipe P is calculated based on the strength of the magnetic field M detected by the magnetic field detection unit 16 and the like.
A "frequency setting signal" for changing the frequency of the AC current AC applied to the water pipe P according to the calculated distance is transmitted to the power feeding device 20, and the hydraulic cylinders 14A to 14C by the drive unit 17 are transmitted. Limit the drive of
And so on.

The storage device of the control unit 15 is used to obtain the distance between the magnetic field detection unit 16 and the water pipe P based on the basic information governing the basic operation of the excavation machine 10 and the magnetic field M detected by the magnetic field detection unit 16. In addition to storing the "distance calculation information" of the above, "distance information" regarding the distance between the magnetic field detection unit 16 and the water pipe P is stored.

Specifically, regarding this "distance information", the storage device has
-"First safe distance information" (for example, "3.5 m" or more) for setting the frequency of the AC current AC to the "first frequency" (for example, "10 kHz"), hereinafter, this distance is referred to as the "first safe distance". "),
-"Second safety distance information" (for example, "2.5 m" or more and less than "3.5 m", hereinafter, this distance for setting the frequency of the AC current AC to the "second frequency" (for example, "30 kHz"). Is called 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 AC current AC to the "third frequency" (for example, "80 kHz"). Is called the "third safe distance"), and
"Drive limit distance information" for limiting the drive of 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 remembered.

When the control unit 15 determines that the distance between the magnetic field detection unit 16 and the water pipe P is a "first safety distance", a "second safety distance", or a "third safety distance", information indicating that fact. Is transmitted to the power feeding device 20, and is controlled to be 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 control unit 15 determines that the "first safety distance" is the "first frequency setting signal", and determines that the "second safety distance" is the "second frequency setting signal". , When it is determined that the distance is the "third safety distance", the "third frequency setting signal" is transmitted to the power feeding device 20, and a predetermined "notification signal" (for example, an audio signal or an audio signal) indicating the distance is transmitted. The image signal) is controlled to be output to the notification unit 18.
As a result, in the power feeding device 20, an AC current AC having a frequency corresponding to each "frequency setting signal" is applied to the water pipe P, while in the notification unit 18, for example, in the case of a speaker, depending on the distance. The notification sound is sounded (such as sounding so that the interval becomes shorter as the "distance" becomes shorter), and if it is a display device, the distance or the like is displayed.

Further, when the control unit 15 determines that the "drive limit distance" is reached, the "drive limit signal" and the "notification signal" indicating that the "drive limit distance" has been reached are sent to the drive unit 17, respectively. , Controls output to the notification unit 18.
As a result, in the drive unit 17, in order to prevent the bucket 13 from moving below the position, the drive of the hydraulic cylinders 14A to 14C is restricted, while in the notification unit 18, it is shown to be in that state. Notification will be made.
The reason why the drive of the hydraulic cylinders 14A to 14C is restricted is that if the bucket 13 moves below the position, there is a high possibility that the water pipe P will be damaged or damaged (hereinafter referred to as "damage or the like"). Because. In this state, since the bucket 13 does not have to move "unnecessarily" below the position, it is not necessary to limit the upward movement of the bucket 13, and the downward movement is not necessary. , If you can work safely, it is not always necessary to prohibit it. In this case, for example, it is possible to make the downward movement speed of the bucket slower than usual.

The notification unit 18 is in that state when the distance between the magnetic field detection unit 16 and the water pipe P is the "first safety distance" to the "third safety distance" and the "drive stop distance". It is a device for notifying an operator of the fact that the safety is present, and is configured to be operated based on a signal output from the control unit 15. It should be noted that such a notification unit 18 can be realized by providing, for example, a speaker, a display device, or the like as described above in the cockpit of the machine body 11.

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

Next, the power feeding device 20 will be described.
As shown 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 the "frequency variable unit" described in the claims.

The control unit 21 is composed of, for example, 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 sets the frequency of the alternating current AC applied to the water pipe P based on the "first frequency setting signal" to the "third frequency setting signal" transmitted from the excavation machine 10. Control to set (change).

In the storage device of the control unit 21, in addition to storing basic information that controls the basic operation of the power feeding device 20, "frequency information" regarding the frequency of the alternating current AC applied to the water pipe P is stored.
Specifically, regarding this "frequency information", the storage device has
"First frequency information" (for example, "10 kHz", hereinafter, this frequency is referred to as "first frequency"), which is set when the "first frequency setting signal" is received.
"Second frequency information" (for example, "30 kHz", hereinafter, this frequency is referred to as "second frequency"), which is set when the "second frequency setting signal" is received.
"Third frequency information" (for example, "80 kHz", hereinafter, this frequency is 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, this frequency is referred to as "default frequency") when the AC current AC is first applied to the exploration target (water pipe P).
Etc. are remembered.

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 by using a known frequency conversion circuit (for example, an inverter). One end of the frequency variable unit 22 is connected to an AC power supply (commercial power supply) of 100 V or 200 V, while the other end is 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 and E2) of the water pipe P via the cable C1 and the cable C2 (FIG. 1). reference).

The communication unit 23 has the same configuration as the communication unit 19 of the excavation machine 10, and is an interface capable of wired or wireless communication with the communication unit 19.

Next, the control process (metal exploration method) performed by the control unit 15 of the excavation machine 10 will be described with reference to FIGS. 1 to 4.
In this control process, the excavating machine 10 and the power feeding device 20 are in a state of being able to communicate with each other, and an AC current AC having a “default frequency” is applied to the exploration target (“water pipe P” in this embodiment). It is configured to be executed on condition that it is applied. The work of applying an alternating current AC to the above "water pipe P" corresponds to the "current applying process" described in the claims.

(Step S101)
As shown in FIG. 3, the control unit 15 of the excavation machine 10 first determines in step S101 whether or not the excavation operation is in progress.
Specifically, the control unit 15 determines whether or not the drive units 17 that operate the booms 12A and 12B and the bucket 13 are being driven.
When the control unit 15 determines that the drive unit 17 is driven, the process is transferred to step S102, and when it is determined that the drive unit 17 is not driven, the control unit 15 ends the control process. The operation of bringing the bucket 13 or the like into the ground corresponds to the "underground approach step" described in the claims.

(Step S102)
In step S102, 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 connected to the water pipe P in the state where the control process is performed. Therefore, if the excavation work is performed at the place "upper side" of the water pipe P, the magnetic field M will be detected by the magnetic field detection unit 16.
When the control unit 15 determines that the magnetic field M has been detected by the magnetic field detection unit 16, it shifts the process to step S103, and when it determines that the magnetic field M has not been detected, the control unit 15 ends this control process. The work 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. It should be noted that such a determination is made by a method for obtaining a known "buried position" (for example, the peak value of the magnetic field M detected when the magnetic field detection unit 16 is moved in the horizontal direction (the machine body 11 is swiveled in the left-right direction). It can be realized by appropriately adopting the method (method obtained based on).
When the control unit 15 determines that the water pipe P is buried below the excavation position, the process is transferred to step S104, and when it is determined that the water pipe P is not buried, the control process ends. If it is clear that the water pipe P is not buried below the excavation position (for example, if it is clear even if it is explored by another exploration device such as an electromagnetic induction type locator), the power supply device. The application of the alternating current AC by 20 may be stopped (determined as "No" in steps S102 and S103). By doing so, it is possible to prevent wasteful power consumption.

(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. In such a determination, a method for obtaining a known "buried depth" (for example, the strength of the magnetic field M that is displaced when the magnetic field detection unit 16 is moved in the vertical direction (the booms 12A and 12B are moved in the vertical direction)). It 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 shifts the process to step S105. The process of step S104 by the control unit 15 corresponds to the "approach degree calculation step" described in the claims.

(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 the "first safe distance" (for example, "3.5 m").
When the control unit 15 determines that the distance between the magnetic field detection unit 16 and the water pipe P is the "first safe distance", the control unit 15 shifts the process to step S106, and these distances must be the "first safe distance". If it is determined, the process is transferred to step S107.

(Step S106)
In step S106, 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 is performed to output the "notification signal" to the notification unit 18.
As a result, the control unit 21 of the power feeding device 20 controls the AC current AC of the "first frequency" (for example, "10 kHz") so as to be applied to the water pipe P (the magnetic field "M1" in FIG. 4). (See), the notification unit 18 will perform notification indicating that it is the "first safe distance".
The control unit 15 transmits a "first frequency setting signal" to the power feeding device 20, controls to output a predetermined "notification signal" to the notification unit 18, and then ends this control process. The process of step S106, the process of step S108 described later, and the process of step S110 by the control unit 15 correspond to the "frequency variable step" described in the claims.

(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 the "second safe 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 shifts the process to step S108, and the distance between them is the "second safety distance". If it is determined that it is not, the process is transferred to step S109.

(Step S108)
In step S108, 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 is performed to output the "notification signal" to the notification unit 18.
As a result, the control unit 21 of the power feeding device 20 controls the AC current AC of the “second frequency” (for example, “30 kHz”) so as to be applied to the water pipe P (the magnetic field “M2” in FIG. 4). (See), the notification unit 18 will perform notification indicating that it is the "second safe distance".
The control unit 15 transmits a "second frequency setting signal" to the power feeding device 20, controls to output a predetermined "notification signal" to the notification unit 18, and then ends this 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 safe 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 safe distance", the control unit 15 shifts the process to step S110, and the distance between them is the "third safe distance". If it is determined that it is not, the process is transferred 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 is performed to output the "notification signal" to the notification unit 18.
As a result, the control unit 21 of the power feeding device 20 controls the AC current AC of the “third frequency” (for example, “80 kHz”) so as to be applied to the water pipe P (the magnetic field “M3” in FIG. 4). (See), the notification unit 18 will perform notification indicating that it is the "third safe distance".
The control unit 15 transmits a "third frequency setting signal" to the power feeding device 20, controls to output a predetermined "notification signal" to the notification unit 18, and then ends this control process.

(Step S111)
In step S111, the control unit 15 provides 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", respectively. It controls the output to the drive unit 17 and the notification unit 18.
In this control process, the distance between the magnetic field detection unit 16 and the water pipe P in the process of step S109 is the "third safe distance" (for example, "1.5 m" or more and less than "2.5 m"). It is performed when it is determined that the case is not, that is, when the "drive limit distance" (for example, less than "1.5 m") is reached.
As a result, in the drive unit 17, the drive of the hydraulic cylinders 14A to 14C is restricted so that the bucket 13 does not move below the position, while the notification unit 18 is notified that the state is in that state. It will be done.

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

That is, in the present 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 existence of the water pipe P can be confirmed with relatively high accuracy. It is possible. In this respect, it can be said that in the present embodiment, it is possible to effectively prevent the water pipe P from being damaged or the like during the excavation work by the excavation machine 10.

Further, in the present embodiment, for the water pipe P,
-When the distance between the magnetic field detection unit 16 and the water pipe P is large, the exploration accuracy is lowered due to noise or the like, but a wide magnetic field M (see the magnetic field "M1" in FIG. 4) is generated. While applying an alternating current AC of "1 frequency" (eg, "10 kHz"),
-When these distances are close, the range is narrowed, but the alternating current of the "third frequency" (for example, "80 kHz") that generates the magnetic field M with high exploration accuracy (see the magnetic field "M3" in FIG. 4). Apply current AC,
Therefore, it is possible to detect the presence of the water pipe P with high accuracy while suppressing the power consumption.

Further, in the present embodiment, when the distance between the magnetic field detection unit 16 and the water pipe P reaches the "drive limit distance" (for example, less than "1.5 m"), the downward movement of the bucket 13 is restricted. Therefore, it is possible to reliably prevent damage to the water pipe P and the like.

In the present embodiment, the AC current AC is applied to the metal water pipe P for exploration, but the technique of the present embodiment (the present invention) can be applied to all kinds of "buried objects" having conductivity. It is possible to apply. In this respect, it can be said that the present invention is excellent in versatility.

Further, in the present embodiment, the frequency of the alternating current AC applied to the water pipe P is configured to be changed "in a stepwise manner" according to the distance between the magnetic field detection unit 16 and the water pipe P (". "First frequency"-> "second frequency"-> "third frequency"), it is also possible to change to "continuous" according to these distances.

Further, 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 detection unit 16 and the water pipe P. However, it can be changed according to the amount of entry of the bucket 13 into the ground. It should be noted that such an approach amount can be obtained by, for example, calculating based on each expansion / contraction amount of the hydraulic cylinders 14A to 14C.

In this case, as in the first embodiment, for example, as the amount of entry of the bucket 13 to the ground increases (decreases), the frequency of the alternating current AC applied to the water pipe P is changed "stepwise". 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 obtaining the amount of entry of the bucket 13 into the ground and its processing correspond to the "vertical position calculation unit" and the "vertical position calculation step" described in the claims, respectively. do.

Specifically, regarding this point, for example, if it is found by an inquiry to a water supply company that a water pipe P having a burial depth of "5 m" is buried near the construction site, the above-mentioned modification (hereinafter referred to as a modification). , Referred to as the "second embodiment")
-When the approach amount of the bucket 13 to the ground is less than "1.5 m", the AC current AC of the "first frequency" (for example, "10 kHz") is applied.
-When the approach amount of the bucket 13 to the ground is "1.5 m" or more and less than "2.5 m", an AC current AC of "second frequency" (for example, "30 kHz") is applied.
-When the approach amount 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 applied.
Such information may be stored in the storage device of the control unit 21 so as to be applied to the water pipe P, respectively.

The burial depth obtained by the above inquiry is a value that tends to fluctuate depending on the conditions of the construction site (for example, the burial status of other buried pipes). Generally, the burial depth is "large" ("5m"). Therefore, when the frequency is set based on the approach amount of the bucket 13 to the ground as in the second embodiment, the above-mentioned example (the entry amount of the bucket 13 to the ground is "2.5 m" or more and "3.5 m". It can be said that it is desirable to anticipate a safe value in the burial depth by inquiry, as in the case of applying the "third frequency" to the water pipe P when it is less than "."

As described above, in the second embodiment, as in the first embodiment,
When the distance between the magnetic field detection unit 16 and the water pipe P is large, the search accuracy is lowered, but the AC current AC of the "first frequency" that generates a wide magnetic field M around the water pipe P. (See the 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 exploration accuracy is applied (see the magnetic field "M3" in FIG. 4).
It is possible.

In this regard, in the second embodiment, the amount of entry of the bucket 13 into the ground is based on the prediction that the water pipe P will be buried at this depth (“5 m” in the above example). 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 detection unit 16 attached to the bucket 13 of the water pipe P. It can be said that the existence can be detected with high accuracy (see FIG. 4 and the like).

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

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

Further, in addition to performing such control, for example, when the amount of entry of the bucket 13 into the ground becomes "1.5 m" or more and less than "2.5 m", an AC current AC of "second frequency" can be applied to the water pipe P. After that, it is also possible to perform the same control as in the first embodiment.
In this case, for example, after applying a "second frequency" alternating current AC to the water pipe P based on the amount of entry of the bucket 13 to the ground, the distance between the magnetic field detection unit 16 and the water pipe P is determined.
-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 "drive limit distance" (for example, less than "1.5 m") is reached, control may be performed to limit the drive of the hydraulic cylinders 14A to 14C.

In the first and second embodiments, the magnetic field detection unit 16 is attached to the inner outer surface of the boom 12B (on the tip side), but it can also be attached to another place, for example, the bucket 13. .. In this case, from the viewpoint of preventing damage, the magnetic field detection unit 16 may be embedded in a predetermined position (for example, the cutting edge) of the bucket 13.

Further, in the first embodiment and the second embodiment, a so-called excavator car (excavator machine 10) is exemplified as an example of the underground work device, but other excavator machines (for example, a so-called boring machine) may also be used. Often, it may be hand-held, for example, a so-called exploration rod or scoop that pierces the ground and explores buried objects in the ground.

Although the embodiment to which the invention made by the present inventor is applied has been described above, the present invention is not limited by the essays and drawings which form a part of the disclosure of the present invention according to this embodiment. That is, it should be added that all other embodiments, examples, operational techniques, etc. made by those skilled in the art based on this embodiment are of course included in the scope of the present invention.

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

Claims (8)

An underground work device that has an underground approach portion that can enter the ground and performs underground work by allowing the underground approach portion to enter the ground.
A metal exploration system including a power feeding device that applies an electric current to a conductive buried object buried in the ground.
A magnetic field detection unit provided in the underground entry portion and detecting a magnetic field generated in the buried object by applying a current by the power feeding device, and a magnetic field detection unit.
It is provided with an approach degree calculation unit for calculating the approach degree of the underground approach portion to the buried object based on the magnetic field detected by the magnetic field detection unit.
The power feeding device is
It has a frequency variable unit that changes the frequency of the current applied to the buried object 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 portion increases the frequency of the current as the degree of proximity increases. The underground work equipment is
The drive unit that drives the underground approach unit and
The metal exploration system according to claim 1 or 2, further comprising a drive control unit that controls the drive of the underground approach portion by the drive unit according to the degree of approach. An underground work device that has an underground approach portion that can enter the ground and performs underground work by allowing the underground approach portion to enter the ground.
A metal exploration system including a power feeding device that applies an electric current to a conductive buried object buried in the ground.
A magnetic field detection unit provided in the underground entry portion and detecting a magnetic field generated in the buried object when the current is applied by the power feeding device.
It is equipped with 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 feeding device is
It has a frequency variable portion that changes the frequency of the current applied to the buried object according to 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 portion increases the frequency of the current as the vertical position becomes downward. The underground work equipment is
The drive unit that drives the underground approach unit and
The metal exploration system according to claim 4 or 5, further comprising a drive control unit that controls driving of the underground approach portion by the drive unit according to the vertical position. A current application process that applies an electric current to a conductive buried object buried in the ground,
An underground approach process that allows an underground approach portion provided in an underground work device that performs underground work to enter the ground, and an underground approach process.
A magnetic field detection step of detecting a magnetic field generated in the buried object by performing the current application step by a magnetic field detection unit provided in the underground entry portion, and a magnetic field detection step.
It is provided with an approach degree calculation step of calculating the approach degree of the underground approach portion to the buried object based on the magnetic field detected by performing the magnetic field detection step.
The current application process is
A frequency variable step of varying the frequency of the current applied to the buried object according to the approach degree calculated by performing the approach degree calculation step is included.
A metal exploration method characterized by this. A current application process that applies an electric current to a conductive buried object buried in the ground,
An underground approach process that allows an underground approach portion provided in an underground work device that performs underground work to enter the ground, and an underground approach process.
A magnetic field detection step of detecting a magnetic field generated in the buried object by performing the current application step by a magnetic field detection unit provided in the underground entry portion, and a magnetic field detection step.
It is provided with a vertical position calculation step for calculating the vertical position of the underground approach portion with respect to a predetermined reference height position.
The current application process is
A frequency variable step of varying the frequency of the current applied to the buried object according to the vertical position calculated by performing the vertical position calculation step is included.
A metal exploration method characterized by this.

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