JPH11153674A - Buried object detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a buried object detector capable of detecting the part extending to different direction from the extending direction in the case where the buried object is supposed to have extending part in the different direction from the extending direction. SOLUTION: A current is generated in a buried object, buried pipe and an electromagnetic wave emitted by this is received with a plurality of reception antennas X1, X2; Y1, Y2; Z of a reception means 2. Each reception antenna X1, X2; Y1, Y2; Z is bar antenna and has axis lines Lx1, Lx2; Ly1, Ly2; Lz respectively parallel to X-axis, Y-axis and Z-axis mutually perpendicular. Even if the buried pipe extends to any direction, the axis line of at least one reception antenna is twisted position of the axis line of buried pipe. When each reception antenna X1, X2; Y1, Y2; Z is in the twisted position, electromagnetic wave may be received. Thus, even in the case the buried pipe has the extending part different from the extending direction, that part can be detected.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a buried object detector for detecting a buried object such as a pipe buried in a concealed place such as underground.

[0002]

2. Description of the Related Art Buried pipes such as gas pipes and water pipes buried in the ground are searched from the ground using a buried object detector to determine the buried position of the buried pipes. The buried object detector has one receiving antenna, which is
An electromagnetic wave radiated from the buried pipe is received by passing a high-frequency current from the transmitter on the ground to the buried pipe. Since the receiving antenna generally has directional characteristics, the direction of the receiving antenna in the buried object detector is determined based on the directional characteristics, and the direction of the buried object detector is changed to receive electromagnetic waves. By finding the position and the direction where the strength is highest, it is estimated that the buried pipe is buried at the measurement point, and the extension direction of the buried pipe at the measurement point can be estimated. Estimating that the buried pipe is buried in this way, moving the buried object detector in the state of estimating the extension direction while observing the reception intensity along the estimated direction of the buried pipe, The location of the buried pipe is specified.

[0003]

In the prior art, the buried position of the buried pipe is specified based on the directional characteristics of one receiving antenna. Therefore, when the buried pipe consists of only a substantially straight extending portion within the measurement target area. Although the buried position can be easily specified over the entire length, it is possible to specify the buried pipe when the extending direction of the buried pipe greatly changes and when the buried pipe is branched. May not be able to detect that there is a part extending in a direction different from that of the buried pipe, and may lose track of the part, and there is a problem that the buried position of the buried pipe in the measurement target area cannot be easily and accurately specified. . In particular, in the case where the buried pipe has a portion extending in the estimated extending direction and a branching portion in addition to this portion, the portion extending in the extending direction can be always detected. In some cases, it may be neglected to change the direction of the buried object detector to search for a branching portion.

As another prior art, Japanese Patent Publication No. Hei 7-52
No. 085 discloses that a buried pipe receives an electromagnetic wave radiated from a buried pipe and measures a buried depth by a fury bar differential antenna in which two horizontal coils arranged at an interval above and below are connected to have opposite polarities. An apparatus for measuring the depth of a buried metal pipe is disclosed. This apparatus is an apparatus for measuring only the depth of a buried pipe, and it is difficult to detect a portion of the buried pipe extending in a direction different from the extending direction. It has the same problem as the above prior art.

Therefore, an object of the present invention is to provide a buried pipe which can easily and accurately specify the buried position of a buried pipe even when the buried object has a portion extending in a direction different from the estimated extending direction. It is to provide an object detector.

[0006]

According to the first aspect of the present invention, a current is generated in a buried object buried in a concealed place, and an electromagnetic wave radiated from the buried object by the current is received by a receiving antenna to bury the object. A buried object detector for detecting an object, comprising a plurality of receiving antennas each having directivity characteristics in mutually different directions.

According to the present invention, a buried object detector for detecting a buried object in a concealed place has a plurality of receiving antennas having mutually different directional characteristics. An electric current is generated in the buried object directly, for example, by directly connecting a power supply, or indirectly by electromagnetic induction, and the electric current radiates an electromagnetic wave from the buried object. Each of the receiving antennas can receive this electromagnetic wave. Each receiving antenna has a directional characteristic in a direction different from each other, and when receiving an electromagnetic wave from a buried object, the reception intensity of the electromagnetic wave received by each receiving antenna is in the direction of the directional characteristic of each receiving antenna. Depends differently. By using a buried object detector equipped with such a receiving means to search for a concealed place such as in the ground or in a building, it is possible to detect a buried object such as a metal pipe and a locating wire. At this time, since the receiving antennas have directional characteristics in mutually different directions, it is possible to prevent a problem that the embedded object cannot be detected due to the positional relationship between the embedded object and the embedded object detector.

[0008] In the state where the presence of the buried object at the measurement point is estimated, the buried object detector is directed in a direction in which the reception intensity of the electromagnetic wave by any one of the receiving antennas becomes highest, and the buried object is detected. The extension direction can be estimated. In this state, the buried object can be identified by moving the buried object detector along the presumed extending direction of the buried object and exploring the underground. Since the buried object detector has a plurality of receiving antennas as described above, when the buried object detector is searched underground while moving the buried object detector to identify the position of the buried object, Even if it has a portion extending in the extension direction in which the extension direction is presumed and a portion extending in a direction different from the extension direction, the electromagnetic wave radiated from the portion extending in the direction different from the extension direction is transmitted to the embedded object detector. It is possible to detect a portion extending in a direction different from the extending direction by receiving by at least one of the remaining receiving antennas other than the one receiving antenna without changing the direction. Therefore, even when the buried object has a portion extending in a direction different from the estimated extending direction, it is possible to reliably and easily detect the portion extending in a direction different from the extending direction without leaking. Can be.

According to a second aspect of the present invention, in the configuration of the first aspect, at least two of the plurality of receiving antennas are respectively selected in the X direction and the Y direction whose directional characteristics are orthogonal to each other. It is characterized by the following.

According to the present invention, there are provided receiving antennas having directional characteristics in the X and Y directions orthogonal to each other. A virtual plane where a buried object is assumed to exist,
For example, an imaginary plane parallel to the surface of the concealed place such as the ground surface and an XY plane including the X direction and the Y direction are parallel, and one of the two receiving antennas, for example, the X direction (or Y direction). The buried object detector is directed in a direction in which the reception intensity of the electromagnetic wave by the receiving antenna having the directional characteristic of (direction) becomes highest. In this state, when the buried object has a portion extending in a direction orthogonal to the estimated extending direction by exploring the underground using the buried object detector, for example, the buried object is T-shaped or L-shaped. In the case of a character shape, such a buried object can be detected quickly and easily.

According to a third aspect of the present invention, in the configuration of the second aspect, at least one of the plurality of receiving antennas has a directional characteristic in a Z direction orthogonal to the X direction and the Y direction. It is characterized by being chosen.

According to the present invention, there is provided a receiving antenna having directional characteristics in the Z direction orthogonal to the X direction and the Y direction. An electromagnetic wave generated by a receiving antenna having a directional characteristic in one of the X direction and the Y direction, for example, the X direction (or the Y direction), in which the imaginary plane assumed to be buried and the XY plane are parallel. The buried object detector is directed in a direction in which the receiving intensity from the buried object received by the receiving antenna having the directional characteristic in the Z direction becomes zero. From this state, the buried object detector is moved parallel to the XY plane in a direction perpendicular to the extending direction of the buried object, so that the reception intensity of the electromagnetic wave by any one of the receiving antennas becomes the highest, and the directional characteristics in the Z direction are improved. Reception intensity of the electromagnetic wave by the receiving antenna
And a second position at which the reception intensity of the electromagnetic wave between one of the reception antennas and the reception antenna having the directional characteristic in the Z direction is equal.

The first position is a direction perpendicular to the XY plane from the buried object, and the second position is a position moved in parallel to the XY plane from the first position, and is a direction connecting the first position and the buried object. And the direction connecting the first and second positions is orthogonal to each other. Further, the second position is in a direction forming an angle of 45 ° from the buried object with respect to the XY plane. As a result, the buried object, the first position, and the second position are respectively located at the vertices of a right-angled isosceles triangle whose oblique side is a line connecting the buried object and the second position. Therefore, the distance from the first position to the buried object is equal to the distance between the first and second positions, and
By measuring the distance between the second position and the second position, the burying depth of the buried object can be specified.

According to a fourth aspect of the present invention, in the configuration of the first aspect, at least two of the plurality of receiving antennas have directional characteristics selected in the same direction. Features.

According to the present invention, at least two receiving antennas having the same directional characteristics are provided. These two
When the end of the buried object is located between the two receiving antennas in a direction orthogonal to the virtual plane including the two receiving antennas, a large difference occurs between the reception strengths of the two receiving antennas. This makes it possible to reliably detect the end of the buried object. Such detection of the end of the buried object is the same for a portion extending in a direction different from the estimated extending direction. Thereby, when the buried object detector is arranged such that the two receiving antennas can receive the electromagnetic wave from the portion extending in the estimated extending direction, the end of this portion is specified, and the extending direction is determined. When the buried object detector is placed in a state where it can receive electromagnetic waves from a portion extending in a direction different from the direction, the end of this portion can be characterized. Therefore, the end, the bent position, and the branch position of the buried object can be reliably specified.

In particular, in the configuration of the invention described in claim 2,
Providing at least two receiving antennas having directional characteristics in one of the X direction and the Y direction makes it easy to specify the buried position of the buried object when the buried object is T-shaped or L-shaped. . Furthermore, by arranging at least two receiving antennas each having a directional characteristic in both the X direction and the Y direction,
In the case of the letter shape and the L shape, the embedded position of the embedded object can be reliably and easily specified.

According to a fifth aspect of the present invention, in the configuration of the first aspect of the present invention, at least one of the plurality of receiving antennas arbitrarily changes a direction of a directional characteristic. It is characterized by being able to.

According to the present invention, a receiving antenna capable of arbitrarily changing the direction of the directivity is provided. In locating the buried object by searching the ground while moving the buried object detector in the supposed direction of the buried object, the buried object extends in a direction different from the extending direction of the buried object. When a part is detected, the direction of the directional characteristic of the receiving antenna can be arbitrarily changed, and the direction of the directional characteristic of the receiving antenna is changed. By specifying the direction of the characteristic, the extending direction of the portion extending in the different direction can be estimated. Further, when specifying the embedding position of the portion extending in the extending direction of the buried object, when it is predicted in advance that there is a portion extending at a predetermined angle with respect to the extending direction, By changing the directional characteristics in the direction in which the reception intensity of electromagnetic waves from that part becomes the highest, and then moving the buried object detector to search underground, it is possible to reliably detect parts extending in different directions. it can.

[0019]

FIG. 1 is a front view showing a main structure of a receiving means 2 provided in an embedded object detector 1 according to an embodiment of the present invention, and FIG. 2 is a reception view seen from above in FIG. FIG. 3 is a plan view of a main configuration of the means 2, and FIG. 3 is a perspective view showing the buried object detector 1. The buried object detector 1 is a device for detecting a buried pipe 3 which is, for example, a cast iron water pipe as a buried object buried in the ground which is a concealed place, and includes a housing 12 and a buried object inside the housing 12. A receiving unit for receiving electromagnetic waves radiated from the tube; and detecting the buried tube by receiving the electromagnetic waves from the buried tube. The buried pipe 3 is a pipe made of cast iron, which is a conductor, and generates a high-frequency current when connected to a power supply 4. An electromagnetic wave is radiated from the buried pipe 3 by this current, and the electromagnetic wave is received by the receiving means 2.

The receiving means 2 has a plurality of receiving antennas (hereinafter sometimes abbreviated as “antennas”) X 1, X 2; Y 1, Y 2, and Z provided on a flat substrate 5. Electromagnetic waves are received from the buried pipe 3 by the antennas X1, X2; Y1, Y2, Z. Each of the antennas X1, X2; Y1, Y2; Z is a so-called bar antenna formed by inserting a core rod made of a magnetic material such as ferrite, which is a material having high magnetic permeability, into a coil. The number of turns of the coil depends on the frequency of the current flowing through the object,
The number of turns that makes it easy to receive the electromagnetic wave radiated by this current is selected.

Referring to FIGS. 4 and 5, as an example,
To describe the antenna X1 in detail, when a current is generated in the buried pipe 3 in the axial direction (the direction perpendicular to the plane of FIG. 4), an electromagnetic wave traveling radially from the buried pipe 3 over the entire circumferential direction is radiated. The intensity of the magnetic field of this electromagnetic wave changes in the circumferential direction of the buried pipe 3. With respect to such a buried pipe 3, when the antenna X1 is in a receiving posture in which the axis Lx1 of the antenna X1 and the axis L3 of the buried pipe 3 are parallel, for example, in the receiving posture 6, the antenna X1 transmits the signal from the buried pipe 3. The reception intensity of the electromagnetic wave is zero. Also, when the axis Lx1 of the antenna X1 and the axis L3 of the buried pipe 3 are orthogonal to each other, that is, when the antenna X1 is in the receiving attitude, for example, the receiving attitude 7 where the axis Lx1 of the antenna X1 matches one diameter line of the buried pipe 3. The reception intensity of the electromagnetic wave from the buried pipe 3 by the antenna X1 is zero. Reception postures other than these reception postures including the reception postures 6 and 7, that is, the axis Lx of the antenna X1
When the antenna X1 is in the receiving posture in which 1 and the axis L3 of the buried tube 3 are twisted, for example, the receiving postures 8, 9, and 10, the reception intensity of the electromagnetic wave from the buried tube 3 by the antenna X1 is a value other than 0. Becomes

Antenna X1 including receiving attitudes 8, 9, and 10
The axis Lx1 of the antenna X1 and the axis L3 of the buried pipe 3 are in a twisted position, the axis Lx1 of the antenna X1 is on a virtual plane perpendicular to the axis L3 of the buried pipe 3, and the axis Lx1 of the antenna X1 is When the antenna X1 is in the receiving position 8 where the one diameter line of the buried pipe 3 is orthogonal to the center of the antenna X1 in the axial direction, the antenna X1 can receive the electromagnetic wave from the buried pipe 3 with the highest reception efficiency. In the receiving position 8, the electromagnetic wave is incident on the antenna X1 in a direction perpendicular to the axis Lx1, and the intensity of the magnetic field changes at the largest change rate in the axial direction of the antenna X1, so that the reception efficiency of the electromagnetic wave is reduced. Will be the highest. Therefore, among the reception postures in which the distance from the buried pipe 3 to the center position of the antenna X1 is equal, when the antenna X1 is in the reception posture 8, the reception intensity of the electromagnetic wave by the antenna X1 is the highest. In other words, in the reception posture in which the distance from the buried pipe 3 to the center of the antenna X1 is equal, the reception intensity when in the reception postures 6 and 7 is 0, which is the lowest, and the reception intensity improves as the position approaches the reception posture 8, The reception intensity when in the reception posture 8 is the highest.

As described above, each of the antennas X1, X2; Y1, Y2, and Z, which are bar antennas, has directional characteristics whose reception intensity varies depending on the incident direction of electromagnetic waves. Each of the antennas X1, X2; Y1, Y2, Z is configured to have the same reception performance so that it can receive with the same intensity when located at the same position with respect to the buried pipe 3. I have.

Each antenna X1, X2; Y1, Y2; Z
Is the axis Lx1, Lx2; Ly1, Ly2; Lz,
It is provided so as to be parallel to predetermined three orthogonal axes, that is, an X-axis extending in the left-right direction of FIG. 1, a Y-axis extending in the up-down direction of FIG. 1, and a Z-axis perpendicular to the paper surface of FIG. Each axis Lx of each antenna X1, X2; Y1, Y2
1, Lx2; Ly1 and Ly2 exist on a virtual plane parallel to the XY plane including the X axis and the Y axis.
The antennas 1 and X2 are arranged at intervals in the direction parallel to the Y axis, and the antennas Y1 and Y2 are arranged at intervals in the direction parallel to the X axis. Each antenna X1,
The center position of X2 is the axis Ly of each antenna Y1, Y2.
1 and Ly2, and the center position of each antenna Y1, Y2 is the axis Lx1, Lx of each antenna X1, X2.
The antenna X2 is located closer to the antenna X2. Antenna Z
Is arranged on the opposite side of the antenna X1 with respect to the antenna X2, the axis Lz is located at the center between the axes Ly1 and Ly2 of the antennas Y1 and Y2, and the center of the antenna Z is located at the respective antennas X1 and X2; It is located on an imaginary plane including the axes Lx1 and Lx2 of Y1 and Y2; Ly1 and Ly2.

According to the present invention, the direction of the directional characteristic capable of receiving the electromagnetic wave incident perpendicularly to the X axis while the magnetic field changes in the direction parallel to the X axis with the highest efficiency is defined as the X direction. The direction of the directional characteristic capable of receiving the electromagnetic wave incident perpendicularly to the Y axis while changing in a direction parallel to the axis with the highest efficiency is defined as the Y direction, and the magnetic field changes in the direction parallel to the Z axis while the Z direction changes. The direction of the directional characteristic capable of receiving the electromagnetic wave incident perpendicular to the axis with the highest efficiency is Z
Direction. That is, the antennas X1 and X2 have the same directional characteristics in the X direction, and the antennas Y1 and Y2
Have the same directional characteristics in the Y direction, and the antenna Z has the directional characteristics in the Z direction. The directions of these directional characteristics, that is, the X direction, the Y direction, and the Z direction are orthogonal to each other, and the antennas X1 and X2 and the antennas Y
1, Y2 and the antenna Z have directivity characteristics orthogonal to each other.

The buried object detector 1 is provided with such a receiving means 2.
In addition, a processing unit 15 and a display unit 16 are provided. Each of the antennas X1, X2; Y1, Y2, Z gives a signal indicating the reception intensity of the received electromagnetic wave to the processing means 15, respectively. The processing means 15 is realized by, for example, a microcomputer, and each of the antennas X1, X2; Y
1, a display signal representing the reception intensity of each of the antennas X1, X2; Y1, Y2; Z is given to the display means 16 based on the signals given from the antennas 1, 1, Y2; The display means 16 controls each of the antennas X1, X2; Y1, Y2;
The display content indicating the reception intensity by Z is displayed.

The buried object detector 1 has wheels 17 on one side of the housing 1, in the present embodiment, at the bottom, and is mounted on the ground surface via the wheels 17 to move along the ground surface. While exploring the ground. The operator checks the reception intensity of the antennas X1, X2; Y1, Y2, Z from time to time while moving the buried object detector 1 by the display means, whereby the buried pipe 3 is buried at the measurement point. Can be estimated.

The receiving means 2 is housed in the housing 12 with the buried object detector 1 placed on a flat ground surface such that the XY plane is parallel to the ground surface. Generally, the buried pipe 3 is buried in parallel with the ground surface, whereby the buried pipe 3 is located parallel to the XY plane. The receiving means 2 of the buried object detector 1 is arranged in the X direction, the Y direction
Antennas X1, X2; Y1, Y2, Z having directional characteristics in the direction and the Z direction, respectively, and at least one of the antennas X1, X2; Y1, Y2, Z has its axis Lx1, Lx2; Ly1, Ly2;
When Lz is at a position twisted with respect to the axis L3 of the buried pipe 3, and when the buried object detector 1 is searched underground using the buried object detector 1, if the buried object detector 1 is located near the buried pipe 3, each antenna X1,
At least one of X2; Y1, Y2; Z can receive an electromagnetic wave from the buried pipe 3. As a result, the buried pipe 3 can be reliably detected, and the buried pipe 3 can be detected.
A problem that the buried pipe 3 cannot be detected due to the positional relationship between the buried pipe 3 and the buried object detector 1 can be prevented.

Generally, the buried pipe 3 is buried almost in parallel with the ground surface. In this case, the procedure of detecting the buried pipe 3 by the buried object detector 1 will be described. When the buried pipe 3 is buried substantially parallel to the ground surface, the buried pipe 3 is positioned substantially parallel to the XY plane. In such a case, any one of the antennas X1, X2; Y1, Y2; Z may receive any electromagnetic wave and estimate that the buried pipe 3 is buried at the measurement point.
In the present embodiment, the buried object detector 1 is directed in a direction in which the reception intensity of the electromagnetic wave by the antenna X1 becomes highest. At this time, it can be estimated that the antenna X1 is in the receiving position 8 with respect to the buried pipe 3 and that the buried pipe 3 is at a position intersecting a straight line perpendicular to the ground surface passing through the center of the antenna X1. And the antennas Y1 and Y2 are in the receiving position 6 with respect to the buried pipe 3, and the axis L3 of the buried pipe 3 is Y
It extends parallel to the axis. Further, when the antenna X2 is receiving the electromagnetic wave from the buried pipe 3 at the highest reception intensity, similarly to the antenna X1, the buried pipe 3 intersects with a straight line passing through the center of the antenna X2 and perpendicular to the ground surface. You can guess what you are doing.

The buried object detector 1 is moved along the ground surface while moving the direction from the antenna X1 to the antenna X2 along the supposed extending direction of the buried pipe 3 as the moving direction S. To explore. During this exploration,
When the buried pipe 3 is only the portion 3a extending in the estimated extending direction, the reception intensity by each antenna X1, X2 shows the highest value, and the reception intensity by each antenna Y1, Y2; 0. Each antenna X1, X2; Y
When 1, Y2; Z indicates such reception strength, the receiving means 2 can specify that the buried pipe 3 is only the portion 3a extending in the estimated extending direction.

FIG. 6 shows the shape of the buried tube 3 and each antenna X1,
FIG. 8 is a diagram for explaining an example of a relationship with reception intensity by X2; Y1 and Y2, and is a diagram showing an example of a transition of reception intensity by each antenna X1 and X2; Y1 and Y2 when the buried pipe 3 is detected. is there. FIG. 7 shows that a moving direction S of the buried object detector 1 is provided on a portion 3a of the buried pipe 3 extending in the estimated extending direction.
The case where the power supply 4 is connected and the voltage is applied on the upstream side is shown, the horizontal axis shows the position of the buried object detector 1 with respect to the buried pipe 3 in the moving direction S, and the vertical axis shows each antenna X
1, X2; indicates the reception intensities of Y1 and Y2. Referring to FIGS. 6 and 7, buried pipe 3 and each antenna X1, X
2. A criterion for specifying a two-dimensional positional relationship of Y1, Y2 projected on the XY plane from the reception strength of each of the receiving antennas X1, X2; Y1, Y2 will be described.

As shown in FIG. 6A, the buried pipe 3 has a portion 3a extending in an estimated extending direction, and a right end to the moving direction S from the downstream end of the portion 3a in the moving direction S. When the antenna X is detected by using the buried object detector 1 along the portion 3a extending in the estimated extending direction, the antenna X
The reception intensities of 1, X2; Y1 and Y2 follow a transition as shown in FIG. The buried object detector 1 is connected to the antenna X
The exploration proceeds in the movement direction S while specifying the embedment position of the portion 3a of the buried pipe 3 so that the first and X2 take the receiving posture 8 with respect to the portion 3a of the buried pipe 3.

At this time, the moving direction S of the portion 3a of the buried pipe 3
Since the current due to the voltage applied on the upstream side decreases as it moves downstream in the movement direction S, the reception intensity of each of the antennas X1 and X2 decreases as it moves downstream in the movement direction.
Decreases at a constant rate. Further, since the antenna X2 is located on the downstream side in the movement direction from the antenna X1, the reception intensity of the antenna X2 is lower than the reception intensity of the antenna X1. When each of the antennas X1 and X2 is located downstream of the bending position 20 in the movement direction, as the antenna X1 and X2 advance in the movement direction S, the reception intensity of each antenna X1 and X2 increases.
It decreases at a higher reduction rate than the reduction rate when it is located on the upstream side in the movement direction.

When the buried object detector 1 conducts an exploration as described above, the buried object detector moves the buried pipe 3 at the bending position 20.
Approaching, the antennas Y1 and Y2 approach the portion 3b of the buried tube 3 and start receiving electromagnetic waves from the portion 3b of the buried tube 3, and their reception intensities increase at a constant rate as approaching the bending position 20. To increase. When the buried object detector 1 exceeds the bending position 20 of the buried pipe 3, each antenna Y1, Y2
Moves away from the portion 3b of the buried pipe 3, and the reception strength of each decreases at a constant rate as the distance from the bending position 20 increases. At this time, since the portion 3b of the buried pipe 3 is located on the right side with respect to the moving direction S, the reception strength of the antenna Y2 is higher than the reception strength of the antenna Y1.

When the buried object detector 1 is used to search the underground and the reception intensity of each of the antennas X1, X2; Y1, Y2 follows such a transition, the buried pipe 3 moves to the right with respect to the moving direction S. It is detected that the shape is an L-shaped bent, and the embedding position can be specified. At this time, the bending position 20 includes a position 36 where the rate of decrease in the reception intensity of the antenna X1 is large and a position 37 where the rate of decrease in the reception intensity of the antenna X2 is large.
Between the antennas Y and Y.
This is the position where the reception strength of Y1 and Y2 is the highest.

Referring to FIG. 8, the procedure for specifying the bending position 20 from the change in the reception intensity of the antenna Y2 will be described. The object detector 1 is located at a position 3 far from the bending position 20 of the buried pipe 3.
0, the antenna Y2 is connected to the portion 3b of the buried pipe 3.
Distant from the vehicle, does not receive electromagnetic waves, and the reception intensity is 0
It is. As the buried object detector 1 approaches the bent position 20 of the buried pipe 3 from such a position 30, the antenna Y2 approaches the portion 3b of the buried pipe 3 and the reception intensity starts to increase gradually. The buried object detector 1 is located at a position where the portion on the downstream side in the moving direction of the antenna Y2 overlaps with the portion 3b of the buried tube 3 and a position where the center position of the antenna Y1 overlaps with the portion 3b of the buried tube 3, that is, when the antenna Y2 is Part 3b of buried pipe 3
Arrives at the position 32 where the receiving posture 8 becomes, and at this position 32, the receiving strength of the antenna Y2 becomes the highest.
Further, the buried object detector 1 moves to a position 33 where a portion on the upstream side in the moving direction of the antenna Y2 overlaps with the portion 3b of the buried pipe 3, and with the movement of the buried object detector 1, the antenna Y
2, the reception intensity decreases.

The moving distance of the buried object detector 1 is calculated from the number of rotations of the wheel 17, and based on this, the buried object detector 1 is moved.
Each time moves a predetermined distance, the reception intensity of the antenna Y2 at the measurement point is recorded in the memory in the processing means 15. The reception intensity of the antenna Y2 at the new measurement point is compared with the reception intensity of the antenna Y2 at the immediately preceding measurement point, and when the reception intensity of the new antenna Y2 is reduced below the previous reception intensity, The position of the buried object detector 1 that has received the previous record, that is, the measurement point is the position where the reception intensity of the antenna Y2 is the highest, and the position of the buried object detector 1 at this time, more precisely, XY When projected onto a plane, the position that matches the intersection of the straight line passing through each antenna X1 and X2 and the straight line passing through each antenna Y1 and Y2 is:
This is the bending position 20 of the buried pipe 3.

Also, the buried pipe 3 is replaced with the part 3b, and FIG.
(1) When there is a portion 3c indicated by a virtual line, that is, a portion 3a in which the buried pipe 3 extends in an estimated extending direction,
The moving direction S from the downstream end of the portion 3a in the moving direction S
In the case of an L-shape having a portion 3c which is bent to the left and extends perpendicularly to the left side, each of the shapes when the object is detected using the buried object detector 1 along the portion 3a extending in the estimated extending direction The reception intensities of the antennas X1, X2; Y1, Y2 are shown in FIG.
Follow the transition as shown in (2). Buried object detector 1
The search proceeds in the moving direction S while the antennas X1 and X2 specify the embedment position of the portion 3a of the buried tube 3 so that the antennas X1 and X2 take the receiving posture 8 with respect to the portion 3a of the buried tube 3. At this time, the current due to the voltage applied on the upstream side in the moving direction S of the portion 3a of the buried pipe 3 decreases as it goes downstream in the moving direction S. The intensity decreases at a constant rate. Further, since the antenna X2 is located on the downstream side in the movement direction from the antenna X1, the reception intensity of the antenna X2 is lower than the reception intensity of the antenna X1. Each antenna X
When X1 and X2 are located downstream of the bending position 20 in the movement direction, the antennas X
The reception intensities of 1 and X2 decrease at a higher rate than the rate at which the reception strength is located upstream of the bending position 20 in the moving direction.

When the buried object detector 1 conducts an exploration as described above, the buried object detector is moved to the bent position 20 of the buried pipe 3.
, The antennas Y1 and Y2 approach the portion 3c of the buried tube 3 and start receiving electromagnetic waves from the portion 3c of the buried tube 3, and their reception intensities increase at a constant rate toward the bending position 20. To increase. At this time, since the portion 3c of the buried pipe 3 is located on the left side with respect to the moving direction S,
The reception strength of the antenna Y2 is lower than the reception strength of the antenna Y1. The buried object detector 1 is at the bending position 2 of the buried pipe 3
When the distance exceeds 0, the antennas Y1 and Y2 move away from the portion 3c of the buried pipe 3, and the respective reception strengths decrease at a constant rate as the distance from the bending position 20 increases. At this time, since the portion 3c of the buried pipe 3 is located on the left side with respect to the movement direction S, the reception strength of the antenna Y1 is higher than the reception strength of the antenna Y2.

When the receiving intensity of each antenna X1, X2; Y1, Y2 traces such a search using the buried object detector 1, the buried pipe 3 bends to the left with respect to the moving direction S. An L-shape is detected, and the embedding position can be specified. At this time, the bending position 20 is a center position between a position 36 at which the rate of decrease of the reception intensity of the antenna X1 increases and a position 37 at which the rate of decrease of the reception intensity of the antenna X2 increases. , Y2
Is the position where the reception intensity of the signal is highest. This position can be specified in the same manner as in the case of an L-shape bent rightward as shown in FIG.

As shown in FIG. 6 (2), the buried pipe 3 is branched from a part 3a extending in the supposed extending direction and from a middle part of the part 3a vertically to the right with respect to the moving direction S. In the case of a T-shape having an extending portion 3b, each of the antennas X1, X2; Y1, Y when the object is detected using the buried object detector 1 along the portion 3a extending in the estimated extending direction.
The reception intensity of No. 2 follows a transition as shown in FIG. The buried object detector 1 is connected to the antennas X1 and X2 by the buried pipe 3
In order to take the receiving posture 8 with respect to the portion 3a of the buried pipe 3, the moving direction S
Exploration proceeds. At this time, the current due to the voltage applied on the upstream side in the moving direction S of the portion 3a of the buried pipe 3 decreases as it goes downstream in the moving direction S. Therefore, as the current progresses downstream in the moving direction, reception by each of the antennas X1 and X2 occurs. The intensity decreases at a constant rate. The antenna X2 is
Since the antenna X2 is located on the downstream side in the movement direction with respect to the antenna X1, the reception intensity of the antenna X2 is lower than the reception intensity of the antenna X1. Since the current of the buried pipe 3 is branched at the branch position 21, the estimated current of the portion 3 a extending in the extending direction is greatly different between the branch position 21 on the upstream side in the moving direction and on the downstream side in the moving direction. The reduction rate of the reception strength near 21 is larger than that of the remaining parts.

When the buried object detector 1 conducts an exploration as described above, the buried object detector moves to the branch position 21 of the buried pipe 3.
, The antennas Y1 and Y2 approach the portion 3b of the buried tube 3 and start receiving electromagnetic waves from the portion 3b of the buried tube 3, and their reception intensities increase at a constant rate toward the branch position 21. To increase. When the buried object detector 1 exceeds the branch position 21 of the buried pipe 3, each antenna Y1, Y2
Moves away from the portion 3b of the buried pipe 3, and the reception strength of each decreases at a constant rate as the distance from the branch position 21 increases. At this time, since the portion 3b of the buried pipe 3 is located on the right side with respect to the moving direction S, the reception strength of the antenna Y2 is higher than the reception strength of the antenna Y1.

When the receiving intensity of each of the antennas X1 and X2; Y1 and Y2 traces such a search using the buried object detector 1, the buried pipe 3 branches rightward with respect to the moving direction S. It is detected that it is T-shaped, and the embedding position can be specified. At this time, the branch position 21 is the center position of the region where the reduction rate of the reception intensity of each antenna X1 and X2 is large, and this position is the position where the reception intensity of each antenna Y1 and Y2 is the highest. The identification of this position
It can be specified in the same manner as in the case of the L-shape bent to the right shown in FIG.

Also, the buried pipe 3 is replaced with the portion 3b, and FIG.
(2) When there is a portion 3c indicated by a virtual line, that is, the buried pipe 3 has a portion 3a extending in an estimated extending direction;
In the case of a T-shape having a portion 3c that branches from the middle of the portion 3a to the left in the moving direction S and extends perpendicularly to the moving direction S, a buried object is detected along the portion 3a extending in the estimated extending direction. Antennas X1, which were detected by using the detector 1,
The reception intensities of X2; Y1 and Y2 follow a transition as shown in FIG. The buried object detector 1 is connected to the antennas X1 and X
The search progresses in the movement direction S while specifying the embedment position of the portion 3a of the buried pipe 3 so that the 2 takes the receiving posture 8 with respect to the portion 3a of the buried pipe 3. At this time, the current due to the voltage applied on the upstream side in the moving direction S of the portion 3a of the buried pipe 3 decreases as it goes downstream on the moving direction S.
As the antenna travels downstream in the movement direction, the antennas X1, X
2 decreases at a fixed rate. Further, since the antenna X2 is located on the downstream side in the movement direction from the antenna X1, the reception intensity of the antenna X2 is
Lower than the reception strength of The current of the buried pipe 3
1, the estimated current of the portion 3 a extending in the extending direction is greatly different between the upstream and the downstream in the moving direction with respect to the branch position 21.
The reduction rate of the reception intensity in the vicinity is larger than the reduction rate in the remaining part.

When the buried object detector 1 conducts an exploration as described above, the buried object detector 1 moves to the branch position 2 of the buried pipe 3.
1, the antennas Y1 and Y2 approach the portion 3c of the buried tube 3 and start receiving electromagnetic waves from the portion 3c of the buried tube 3, and the respective reception intensities have a constant ratio as approaching the branch position 21. To increase. When the buried object detector 1 exceeds the branch position 21 of the buried pipe 3, each of the antennas Y1, Y
2 moves away from the portion 3 c of the buried pipe 3, and the respective reception strengths decrease at a constant rate as the distance from the branch position 21 increases. At this time, since the portion 3c of the buried pipe 3 is located on the left side with respect to the movement direction S, the reception strength of the antenna Y1 is higher than the reception strength of the antenna Y2.

When a search is performed using the buried object detector 1 and the reception intensities of the antennas X1 and X2; Y1 and Y2 follow such a transition, the buried pipe 3 branches to the left with respect to the moving direction S. It is detected that it is T-shaped, and the embedding position can be specified. At this time, the branch position 21 is the center position of the region where the reduction rate of the reception intensity of each antenna X1 and X2 is large, and this position is the position where the reception intensity of each antenna Y1 and Y2 is the highest. The identification of this position
It can be specified in the same manner as in the case of the L-shape bent to the right shown in FIG.

As shown in FIG. 6 (3), the buried pipe 3 has a portion 3a extending in the direction in which it is supposed to extend, and both left and right sides in the moving direction S from the downstream end of the portion 3a in the moving direction. A portion 3 which branches vertically to and extends in a straight line
b, 3c, reception of each antenna X1, X2; Y1, Y2 when using the buried object detector 1 to search along the portion 3a extending in the estimated extending direction. The intensity follows a transition as shown in FIG. The buried object detector 1 is directed so that the antennas X1 and X2 assume the receiving position 8 with respect to the portion 3a of the buried pipe 3, and the search is performed in the moving direction S while specifying the buried position of the portion 3a of the buried pipe 3. proceed. At this time, the moving direction S of the portion 3a of the buried pipe 3
Since the current due to the voltage applied on the upstream side decreases as it moves downstream in the movement direction S, the reception intensity of each of the antennas X1 and X2 decreases as it moves downstream in the movement direction.
Decrease by a certain rate. Also, since the antenna X2 is located on the downstream side in the movement direction from the antenna X1, the antenna X
2 is lower than the reception intensity of the antenna X1.
When each of the antennas X1 and X2 is located downstream of the branch position 21 in the moving direction, as the antenna advances in the moving direction S, the reception intensity of each antenna decreases when the antenna is located upstream of the branch position 21 in the moving direction. Decrease at a higher rate of decrease.

When the buried object detector 1 conducts an exploration as described above, the buried object detector moves to the branch position 21 of the buried pipe 3.
, The antennas Y1 and Y2 approach the portions 3b and 3c of the buried tube 3 and start receiving electromagnetic waves from the portions 3b and 3c of the buried tube 3, and the respective reception intensities reach the branch position 21. It increases at a constant rate as it approaches. When the buried object detector 1 moves beyond the branch position 21 of the buried pipe 3, the antennas Y1 and Y2 move away from the respective portions 3b and 3c of the buried pipe 3, and the respective reception intensities become constant as the distance from the branch position 21 increases. Decrease in percentage. At this time, since the buried pipe 3 is located on both sides of each of the portions 3b and 3c on the left and right sides, the reception strengths of the antennas Y1 and Y2 are equal.

When the receiving intensity of each of the antennas X1 and X2; Y1 and Y2 traces such a search using the buried object detector 1, the buried pipe 3 branches to the left and right sides with respect to the moving direction S. Is detected, and the embedding position can be specified. At this time, the branch position 21 is a center position between a position 36 where the reduction rate of the reception intensity of the antenna X1 increases and a position 37 where the reduction rate of the reception intensity of the antenna X2 increases. This position is determined by the antennas Y1 and Y2.
Is the position where the reception intensity of the signal is highest. This position can be specified in the same manner as in the case of an L-shape bent rightward as shown in FIG.

As shown in FIG. 6D, the buried pipe 3 has only a portion 3a extending in the estimated extending direction, and when the terminal 22 is present, the portion extending in the estimated extending direction. FIG. 7 shows the reception intensity of each antenna X1, X2; Y1, Y2 when the buried object detector 1 is searched along 3a.
Follow the transition as shown in (6). Buried object detector 1
The search proceeds in the moving direction S while the antennas X1 and X2 specify the embedment position of the portion 3a of the buried tube 3 so that the antennas X1 and X2 take the receiving posture 8 with respect to the portion 3a of the buried tube 3. At this time, the current due to the voltage applied on the upstream side in the moving direction S of the portion 3a of the buried pipe 3 decreases as it goes downstream in the moving direction S. The intensity decreases at a constant rate. Further, since the antenna X2 is located downstream of the antenna X1 in the moving direction, the reception intensity of the antenna X2 is
It is lower than the reception intensity of the antenna X1. Each antenna X1,
When X2 is located downstream of the terminal 22 in the movement direction, as the antenna travels in the movement direction S, the reception intensity of each antenna increases at a reduction rate higher than that at the time of being located upstream of the terminal 22 in the movement direction. Decrease.

When the above-described search is performed using the buried object detector 1, the antennas Y1 and Y2 do not have a portion where the buried pipe 3 is twisted with the antennas Y1 and Y2. The reception intensity of each of the antennas Y1 and Y2 is 0 regardless of the position of the buried object detector 1.

The underground object is detected by the buried object detector 1, and when the reception intensities of the antennas X1, X2; Y1, Y2 follow such a transition, it is detected that the buried pipe 3 has the terminal 22. The buried position can be specified. At this time, the terminal 22 is the center position between the position 36 where the rate of decrease of the reception intensity of the antenna X1 is large and the position 37 where the rate of decrease of the reception intensity of the antenna X2 is large. The position is specified in the same manner as in the case of the L-shaped bent to the right shown in FIG. That is, the reception intensity at the new measurement point is compared with the reception intensity at the immediately preceding measurement point, and the positions 36 and 37 where the reduction rate of the reception intensity of each of the antennas X1 and X2 becomes large are specified. The position can be specified.

Since the receiving intensities of the antennas X1 and X2; Y1 and Y2 of the receiving means 2 differ according to the shape of the buried pipe 3, the buried object detector 1 is searched and the position of the buried pipe 3 is determined. When the buried pipe 3 has a portion 3a extending in an estimated extending direction and portions 3b and 3c extending in a direction different from the extending direction, the portion 3b extending in a different direction from the extending direction is specified. , 3c is received by at least one of the remaining antennas other than the antenna X1, which is the one antenna, in this embodiment, the antennas Y1 and Y2, and extends in a direction different from the extending direction. Parts 3b and 3c can be detected.
Therefore, even when the buried pipe 3 has the portions 3b, 3c extending in a direction different from the estimated extending direction, the portions 3b, 3c can be reliably detected without detection leak.

Also, antennas X1, X2; Y1, Y2 having directional characteristics in the X and Y directions orthogonal to each other are provided, respectively, and a virtual plane in which the buried pipe 3 is presumed to exist, in this embodiment, , XY plane are parallel to each other, and the buried object detector 1 is directed in a direction in which the reception intensity of the electromagnetic wave by the antenna X1 which is one of the two antennas is highest. In this state, when the buried pipe 3 has portions 3b and 3c extending in a direction perpendicular to the estimated extending direction by exploring the ground using the buried object detector 1, for example, FIG. 1) ~
When the buried pipe 3 as shown in FIG. 6 (3) forms a T-shape or L-shape, such a buried object can be detected quickly and easily.

At least two antennas having the same directional pattern, two antennas X1 and X2 having the directional pattern in the X direction, and two antennas X1 and X2 having the directional pattern in the Y direction.
And two antennas Y1 and Y2. Thus, when the buried pipe 3 and the antennas X1, X2; Y1, Y2 are projected on the XY plane, as shown in FIG.
When the terminal 22 which is the end of the buried pipe 3 is located between the antennas X1 and X2, one of the two antennas, here the antenna X1, receives the electromagnetic wave with high reception intensity, and the other one, Here, the antenna X2 receives the electromagnetic wave at a low reception intensity that is much lower than the reception intensity of the antenna X1. Thereby, the terminal 22 of the buried pipe 3 can be reliably detected. The same applies to the portions 3a and 3b extending in a direction different from the estimated extending direction. As shown in FIGS. 6A and 6B, the portion 3a is provided between the antennas X1 and X2. When the end of
Either one of the two antennas, here the antenna X1 receives the electromagnetic wave with a high reception intensity, and the other one,
Here, the antenna X2 receives the electromagnetic wave at a low reception intensity that is much lower than the reception intensity of the antenna X1, and when the end of the portion 3b (or the portion 3c) is located between the antennas Y1 and Y2, the two antennas One of them,
Here, the antenna Y2 (or the antenna Y1) receives the electromagnetic wave with a high reception strength, and on the other hand, the antenna Y1 (or the antenna Y2) receives the electromagnetic wave far below the reception strength of the reception antenna Y2 (or the antenna Y1). Receive with strength. Therefore, terminal 2 of buried pipe 3
2. The bending position 20 and the branching position 21 can be reliably specified.

FIG. 9 shows a buried pipe 3 using the buried object detector 1.
FIG. 5 is a diagram for explaining a procedure for measuring the burying depth H of the embedment. The ground surface parallel to the virtual plane and the XY plane are parallel to each other and have one of the antennas having the directional characteristics in the X direction and the Y direction. In this embodiment, the reception intensity of the electromagnetic wave by the antenna X2 is the highest. The buried object detector 1 is directed to a state where the reception intensity becomes 0 and the reception intensity received by the antenna Z having the directivity in the Z direction becomes zero. From this state, the buried object detector 1 is moved in parallel to the XY plane in the movement direction S perpendicular to the extending direction of the buried object, so that the reception intensity of the electromagnetic wave by the antenna X2 becomes the highest and the reception intensity of the electromagnetic wave by the antenna Z Are determined to be 0, and a second position 41 at which the reception intensity of the electromagnetic waves of the antennas X and Z is equal.

The first position 40 is in a direction perpendicular to the XY plane from the buried pipe 3, and the second position 41 is a position moved in parallel with the XY plane from the first position.
And the direction connecting the buried pipe 3 and the first and second positions 4
The direction connecting 0 and 41 is orthogonal. Further, the second position 41 is at an angle θ = 45 from the buried pipe 3 with respect to the XY plane.
°. Thereby, the buried pipe 3, the first position 40 and the second position 41 are changed from the buried pipe 3 and the second position 4
It exists at each vertex of a right-angled isosceles triangle with the line segment connecting 1 as the hypotenuse. Therefore, the first and second positions 40,
The distance D between the first position 40 and the buried pipe 3 is equal to the distance H between the first position 40 and the buried pipe 3. By measuring the distance D between the first and second positions 40 and 41, the buried depth H of the buried pipe 3 is obtained.
Can be requested. First and second positions 40, 41
The distance D between them can be determined from the number of rotations of the wheel 17. When the buried object detector 1 is moved from the first position 40 to the second position 41, the reception intensities of the antennas X2 and Z follow a transition as shown in FIG. Each antenna X2
The position where the reception strengths of Z coincide with each other is the second position 41.

FIG. 11 is a front view showing a main structure of a receiving means 2A provided in an embedded object detector 1A according to another embodiment of the present invention, and FIG. 12 is a drawing showing the receiving means 2 as viewed from above in FIG.
It is a top view of the principal part of A. The buried object detector 1A has a configuration similar to that of the buried object detector 1 in the above-described embodiment shown in FIGS. 1 to 10, and only a portion having a configuration different from that of the buried object detector 1 will be described. The portions having the configuration described above are denoted by the same reference numerals as those of the buried object detector 1, and description thereof is omitted. The receiving means 2A of the buried object detector 1A of the present embodiment includes:
One antenna YA is provided instead of the two antennas Y1 and Y2 in the above-described embodiment. This antenna YA is a bar antenna, like the above-described antennas Y1 and Y2, has an axis Lya parallel to the Y axis, and has a directional characteristic in the Y direction. The antenna YA is provided at a position from the antenna X2 such that the axis Lya coincides with a straight line passing through the center of each of the antennas X1 and X2.

FIG. 13 is a diagram showing an example of the transition of the reception intensity of each antenna X1, X2; YA when the buried pipe 3 having the shape shown in FIG. 6 is detected. FIG. 13 shows a case where a voltage is applied on the upstream side in the moving direction S of the portion 3a extending in the estimated extending direction of the buried pipe 3, and the horizontal axis thereof indicates the detection of a buried object with respect to the buried pipe 3 in the moving direction S. Vessel 1
A indicates the position of A, and the vertical axis indicates each antenna X1, X2; YA
This shows the reception strength of.

As shown in FIGS. 6 (1) and 6 (2), the buried pipe 3 has a portion 3a extending in the estimated extending direction.
In the case where the portion 3a has an L-shape having a portion 3b or a portion 3c which is bent from the end of the portion 3a in the moving direction S to one of the left and right sides with respect to the moving direction S and extends vertically. Antennas X1, X when the object is detected using the buried object detector 1 along the portion 3a extending in the extending direction
2: The reception intensity of YA follows a transition as shown in FIG. The buried object detector 1A is directed so that the antennas X1 and X2 assume the receiving posture 8 with respect to the portion 3a of the buried pipe 3, and performs the search in the moving direction S while specifying the buried position of the portion 3a of the buried pipe 3. proceed. At this time, part 3 of the buried pipe 3
The current due to the voltage applied on the upstream side in the moving direction S of a is
Since the distance decreases toward the downstream side in the movement direction S, the reception intensity of each of the antennas X1 and X2 decreases at a constant reduction rate as the line moves downstream in the movement direction. Further, since the antenna X2 is located on the downstream side in the movement direction from the antenna X1, the reception intensity of the antenna X2 is lower than the reception intensity of the antenna X1. Each of the antennas X1 and X2 is at the bending position 2
When it is located on the downstream side in the movement direction from 0, the reception intensity of each antenna X1 and X2 becomes
It decreases at a reduction rate higher than the reduction rate when it is located on the upstream side in the movement direction from the bending position 20.

When the buried object detector 1A approaches the bent position 20 of the buried pipe 3 during the above-described search using the buried object detector 1A, each antenna YA approaches the portion 3b of the buried pipe 3. , The electromagnetic wave from the portion 3b of the buried pipe 3 starts to be received, and the reception intensity increases at a constant rate as the position approaches the bending position 20. Buried object detector 1A is buried pipe 3
Over the bending position 20 of the buried pipe 3
Away from the portion 3b, the reception strength of which is the bending position 2
It decreases at a constant rate as it goes away from zero. At this time, when the antenna YA is projected on the XY plane, the antenna YA is located at a position corresponding to the portion 3a of the buried pipe 3, so that the buried pipe 3
b and the part 3c,
The reception strength of the antenna YA is the same.

The underground is searched using the buried object detector 1A,
When the reception intensities of the antennas X1 and X2; Y1 and Y2 follow such a transition, it is detected that the buried pipe 3 has an L-shape bent to one of the right and left sides with respect to the moving direction S, The buried position can be specified. At this time, the bending position 20 is a center position between a position 36 where the reduction rate of the reception intensity of the antenna X1 is large and a position 37 where the reduction rate of the reception intensity of the antenna X2 is large. Is the position where the reception intensity of the signal is highest. Since the buried pipe 3 is not branched, the bending position 20
, The reception intensity of the antenna YA is
2 is higher than the reception strength. The identification of this position
It can be specified in the same manner as in the case of the L-shape bent to the right shown in FIG.

As shown in FIG. 6 (2), the buried pipe 3 has a portion 3a extending in the direction in which it is supposed to extend, and either one of right and left with respect to the moving direction S from the middle of this portion 3a. In the case of a T-shape having a portion 3b or a portion 3c that branches vertically to the side, when the object is searched using the buried object detector 1A along the portion 3a extending in the estimated extending direction, The reception strength of the antennas X1, X2; YA is shown in FIG.
Follow the transition as shown in (2). Buried object detector 1A
To the antenna 3 so that the antennas X1 and X2 assume the receiving position 8 with respect to the portion 3a of the buried pipe 3, and the search proceeds in the moving direction S while specifying the buried position of the portion 3a of the buried pipe 3.
At this time, the current due to the voltage applied on the upstream side in the moving direction S of the portion 3a of the buried pipe 3 decreases as it goes downstream in the moving direction S. The intensity decreases at a constant rate. Further, since the antenna X2 is located on the downstream side in the movement direction from the antenna X1, the reception intensity of the antenna X2 is lower than the reception intensity of the antenna X1. Since the current of the buried pipe 3 is branched at the branch position 21, the current of the portion 3 a extending in the estimated extending direction is
Is greatly different between the upstream side in the moving direction and the downstream side in the moving direction, and the reduction rate of the reception intensity near the branch position 21 is larger than the reduction rate in the remaining portion.

When the buried object detector 1A approaches the branching position 21 of the buried pipe 3 during the above-described search using the buried object detector 1A, the antenna YA is connected to the portion 3 of the buried pipe 3.
b or the portion 3c, the electromagnetic wave from the portion 3b or 3c of the buried pipe 3 starts to be received, and the reception intensity increases at a constant rate as approaching the branch position 21. When the buried object detector 1A moves beyond the branch position 21 of the buried pipe 3, each antenna YA moves away from the portion 3b or 3c of the buried pipe 3, and the reception intensity decreases at a constant rate as the distance from the branch position 21 increases. I do. At this time, antenna Y
A is located at a position coinciding with the portion 3a of the buried pipe 3 when projected on the XY plane, so that the antenna YA is provided regardless of whether the buried pipe 3 has the portion 3b or the portion 3c. The reception intensity is the same.

Exploring the ground using the buried object detector 1A,
When the reception intensity of each antenna X1, X2; YA follows such a transition, it is detected that the buried pipe 3 has a T-shape that branches to one of the right and left sides with respect to the moving direction S, and the buried position is detected. To identify. At this time, the branch position 21 is the center position of the region where the reduction rate of the reception intensity of each of the antennas X1 and X2 is large, and this position is the position where the reception intensity of the antenna YA is the highest. This position can be specified in the same manner as in the case of an L-shape bent rightward as shown in FIG.

As shown in FIG. 6 (3), the buried pipe 3 has a portion 3a extending in the direction in which it is supposed to extend, and both left and right sides in the moving direction S from the downstream end of the portion 3a in the moving direction. A portion 3 which branches vertically to and extends in a straight line
b, 3c, the reception intensity of each antenna X1, X2; YA when searching using the buried object detector 1A along the portion 3a extending in the estimated extending direction is 13 (3). The buried object detector 1A is oriented so that the antennas X1 and X2 assume the receiving position 8 with respect to the portion 3a of the buried pipe 3, and the search in the moving direction S is performed while specifying the buried position of the portion 3a of the buried pipe 3. proceed. At this time, the moving direction S of the portion 3a of the buried pipe 3
Since the current due to the voltage applied on the upstream side decreases as it moves downstream in the movement direction S, the reception intensity of each of the antennas X1 and X2 decreases as it moves downstream in the movement direction.
Decreases at a constant rate. Further, since the antenna X2 is located on the downstream side in the movement direction from the antenna X1, the reception intensity of the antenna X2 is lower than the reception intensity of the antenna X1. When each of the antennas X1 and X2 is located downstream of the branch position 21 in the moving direction, as the antenna advances in the moving direction S, the reception intensity of each antenna decreases when the antenna is located upstream of the branch position 21 in the moving direction. Decrease at a higher rate of decrease.

When the buried object detector 1A approaches the branching position 21 of the buried pipe 3 during the above-described search using the buried object detector 1A, the antenna YA is connected to the respective portions 3b and 3c of the buried pipe 3. , And starts receiving electromagnetic waves from the respective portions 3b and 3c of the buried pipe 3, and the reception intensity is changed to the branch position 21.
Increases at a constant rate as it approaches. When the buried object detector 1 crosses the branch position 21 of the buried pipe 3, the antenna YA
Moves away from each of the portions 3b and 3c of the buried pipe 3, and the reception intensity thereof decreases at a constant rate as the distance from the branch position 21 increases. At this time, the buried pipe 3 is divided into the parts 3b and 3c.
Are located on the left and right sides of the portion 3a, and the current flows dividedly into the portions 3b and 3c, so that the current is greatly reduced as compared with the portion 3a. Therefore, at the branch position 21, the reception intensity by the antenna YA is lower than the reception intensity by the antenna X2.

When a search is performed using the buried object detector 1A and the reception intensity of each of the antennas X1, X2; YA follows such a transition, the buried pipe 3 branches to the right and left sides with respect to the moving direction S. The character is detected, and the buried position can be specified. At this time, the branch position 21 is a center position between a position 36 where the reduction rate of the reception intensity of the antenna X1 increases and a position 37 where the reduction rate of the reception intensity of the antenna X2 increases, and this position is the reception intensity of the antenna YA. Is the highest position. This position can be specified in the same manner as in the case of an L-shape bent rightward as shown in FIG.

As shown in FIG. 6D, the buried pipe 3 has only a portion 3a extending in the estimated
Is present, the portion 3 extending in the estimated extending direction
FIG. 13D shows the reception intensity of each of the antennas X1 and X2; YA when the buried object detector 1A is searched along a.
Following the transition shown in The buried object detector 1A is directed so that the antennas X1 and X2 assume the receiving posture 8 with respect to the portion 3a of the buried pipe 3, and performs the search in the moving direction S while specifying the buried position of the portion 3a of the buried pipe 3. proceed. At this time, the current due to the voltage applied on the upstream side in the moving direction S of the portion 3a of the buried pipe 3 decreases as it goes downstream in the moving direction S. Therefore, as the current progresses downstream in the moving direction, reception by each of the antennas X1 and X2 occurs. The intensity decreases at a constant rate. Further, since the antenna X2 is located on the downstream side in the movement direction from the antenna X1, the reception intensity of the antenna X2 is lower than the reception intensity of the antenna X1. Each antenna X1, X
2 is located downstream of the terminal 22 in the movement direction, the reception strength of each antenna becomes
It decreases at a higher rate than the rate at which the terminal 22 is located on the upstream side in the movement direction with respect to the terminal 22.

When the buried object detector 1A is searched as described above, the antenna YA is connected to the buried pipe 3 by the antenna YA.
Therefore, the receiving intensity of the antenna YA is 0 regardless of the position of the buried object detector 1A.

When the reception intensity of each antenna X1, X2; YA traces such a search by using the buried object detector 1A, it is detected that the buried pipe 3 has the terminal 22, and the buried object is detected. The position can be specified. At this time, the terminal 22 is the center position between the position 36 where the rate of decrease of the reception intensity of the antenna X1 is large and the position 37 where the rate of decrease of the reception intensity of the antenna X2 is large. This position can be specified in the same manner as in the case of an L-shape bent rightward as shown in FIG. That is, the reception intensity at the new measurement point is compared with the reception intensity at the immediately preceding measurement point, and the positions 36 and 37 where the reduction rate of the reception intensity of each of the antennas X1 and X2 increases are specified, and the center position thereof is determined. Can be specified.

As described above, the buried object detector 1A is provided with the buried pipe 3
Corresponding to the shapes of the antennas X1, X2 of the receiving means;
Since the receiving intensity of the YA is different, when the buried object detector 1A is searched to specify the position of the buried pipe 3, the portion 3a extending in the supposed extending direction of the buried pipe 3 is different from the extending direction. When the antenna has the portions 3b and 3c extending in the directions, the electromagnetic waves radiated from the portions 3b and 3c extending in the direction different from the extending direction are transmitted to at least one of the remaining antennas other than the antenna X1 as the one antenna. YA
And the portions 3b and 3c extending in a direction different from the extending direction can be detected. Therefore, even when the buried pipe 3 has the portions 3b and 3c extending in a direction different from the estimated extending direction, the portions 3b and 3c
3c can be reliably detected without missing detection. The burying depth of the buried pipe 3 can be measured by the same procedure as that of the buried object detector 1.

As another embodiment of the present invention, in each of the above embodiments, each of the antennas X1, X2; Y1, Y2;
, Or each of the antennas X1, X2; Y
Any one of the antennas A; Z may have a configuration that can arbitrarily change the direction of the directional characteristic.
In each of the above embodiments, the receiving means 2 and 2A can arbitrarily change the direction of the directional characteristic in addition to each of the antennas X1, X2; Y1, Y2; Z, or in addition to each of the antennas X1, X2; YA; An antenna that can be changed may be provided.

With this configuration, when a portion extending in a direction different from the extending direction of the buried pipe 3 is detected, the direction of the directional characteristic of the antenna can be arbitrarily changed. The direction in which the portion extending in a direction different from the extending direction is determined by specifying the direction of the directional characteristic in which the reception intensity of the electromagnetic wave from the portion extending in the direction different from the extending direction is highest. Can be inferred. Inferred buried pipe 3
In specifying the buried position of the buried pipe 3 by exploring in the extending direction, if it is predicted in advance that there is a portion extending at a predetermined angle with respect to the extending direction, the portion is specified. By performing a search after changing the directivity in a direction in which the reception intensity of the electromagnetic wave from the antenna becomes highest, it is possible to reliably detect a portion extending in the different direction. When the buried pipe 3 has a portion extending in a direction other than the direction perpendicular to the extending direction, for example, when it is Y-shaped, or when it is bent or curved in a direction other than a right angle, it is surely, quickly and easily. The buried position can be specified.

As another embodiment of the present invention, in order to generate a current in the buried pipe 3, a transmitter is built in the buried object detector 1, 1A instead of directly connecting a power source to the buried pipe 3. Then, an electromagnetic wave may be transmitted to the buried pipe 3 to generate a current by electromagnetic induction. In such a case, even if the buried pipe 3 is connected at the connection portion by using a packing made of an electrically insulating material such as rubber and the like, and the current is cut off at this connection portion, the buried pipe 3 may be buried. Since an electric current can be generated in the buried pipe 3 by the electromagnetic waves from the object detectors 1 and 1A, the buried pipe 3 can be reliably detected. When this electromagnetic induction is used, it is also possible to search for a gas pipe or the like. Further, a stationary type transmitter may be used.

Further, the present invention is not limited to the configuration of the above-mentioned buried object detectors 1 and 1A, but can be changed to another configuration. For example, the number and arrangement position of each antenna can be changed. Needless to say, an antenna of this type such as a loop antenna may be used as the antenna. As an example, the antenna Z may be disposed between the antennas X1 and X2 and at a position 50 between the antennas Y1 and Y2 as shown by a virtual line in FIG. Buried pipe 3
Can be detected. As another example, two antennas having directional characteristics in the Z direction may be provided at intervals in the X axis direction. In such a case,
By performing depth measurement once as described with reference to FIG. 9, it is also possible to determine the inclination direction of the buried pipe 3 at the position with respect to the ground surface from the reception intensity of the two antennas in the Z direction.

Further, the buried object detectors 1 and 1A may be used for detecting other buried objects such as gas pipes and buried objects such as locating wires. For example, it may be used to detect a buried object buried in another concealed place. Even in such a case, when the buried object is made of a conductor, the detection can be similarly performed.

[0078]

As described above, according to the present invention, a buried object detector for detecting a buried object in a concealed place has a plurality of receiving antennas having mutually different directional characteristics.
For example, the power supply is directly connected to the buried object,
Alternatively, a current is generated indirectly by electromagnetic induction, and the current radiates an electromagnetic wave from the buried object. Each of the receiving antennas can receive this electromagnetic wave. Each receiving antenna has a directional characteristic in a direction different from each other, and when receiving an electromagnetic wave from a buried object, the reception intensity of the electromagnetic wave received by each receiving antenna is in the direction of the directional characteristic of each receiving antenna. Depends differently. By using a buried object detector equipped with such a receiving means to search for a concealed place such as in the ground or in a building, it is possible to detect a buried object such as a metal pipe and a locating wire. At this time, since the receiving antennas have directional characteristics in mutually different directions, it is possible to prevent a problem that the embedded object cannot be detected due to the positional relationship between the embedded object and the embedded object detector.

With the presence of the buried object at the measurement point estimated, the buried object detector is turned in a direction in which the reception intensity of the electromagnetic wave by any one of the receiving antennas becomes highest, and the buried object is detected. The extension direction can be estimated. In this state, the buried object can be identified by moving the buried object detector along the presumed extending direction of the buried object and exploring the underground. Since the buried object detector has a plurality of receiving antennas as described above, when the buried object detector is searched underground while moving the buried object detector to identify the position of the buried object, Even if it has a portion extending in the extension direction in which the extension direction is presumed and a portion extending in a direction different from the extension direction, the electromagnetic wave radiated from the portion extending in the direction different from the extension direction is transmitted to the embedded object detector. It is possible to detect a portion extending in a direction different from the extending direction by receiving by at least one of the remaining receiving antennas other than the one receiving antenna without changing the direction. Therefore, even when the buried object has a portion extending in a direction different from the estimated extending direction, it is possible to reliably and easily detect the portion extending in a direction different from the extending direction without leaking. Can be.

According to the present invention, there are provided receiving antennas having directional characteristics in the X and Y directions orthogonal to each other. A virtual plane presumed to have a buried object, for example, a virtual plane parallel to the surface of the concealed place such as the ground surface, and an XY plane including the X direction and the Y direction are parallel to each other, and one of the two receiving antennas The buried object detector is directed to one of the receiving antennas, for example, a direction in which the reception intensity of the electromagnetic wave by the receiving antenna having the directional characteristics in the X direction (or the Y direction) becomes highest. In this state, when the buried object has a portion extending in a direction orthogonal to the estimated extending direction by exploring the underground using the buried object detector, for example, the buried object is T-shaped or L-shaped. In the case of a character shape, such a buried object can be detected quickly and easily.

According to the present invention, there is provided a receiving antenna having directional characteristics in the Z direction orthogonal to the X direction and the Y direction. An electromagnetic wave generated by a receiving antenna having a directional characteristic in one of the X direction and the Y direction, for example, the X direction (or the Y direction), in which the imaginary plane assumed to be buried and the XY plane are parallel. The buried object detector is directed in a direction in which the receiving intensity from the buried object received by the receiving antenna having the directional characteristic in the Z direction becomes zero. From this state, the buried object detector is moved X in the direction orthogonal to the extending direction of the buried object.
A first position at which the reception intensity of the electromagnetic wave by one of the receiving antennas is maximized and the reception intensity of the electromagnetic wave by the reception antenna having the directional characteristic in the Z direction is 0, A second position at which the reception intensity of the electromagnetic wave between one of the receiving antennas and the receiving antenna having the directional characteristic in the Z direction is specified.

The first position is in a direction perpendicular to the XY plane from the embedded object, and the second position is a position moved from the first position in parallel to the XY plane, and is a direction connecting the first position and the embedded object. And the direction connecting the first and second positions is orthogonal to each other. Further, the second position is in a direction forming an angle of 45 ° from the buried object with respect to the XY plane. As a result, the buried object, the first position, and the second position are respectively located at the vertices of a right-angled isosceles triangle whose oblique side is a line connecting the buried object and the second position. Therefore, the distance from the first position to the buried object is equal to the distance between the first and second positions, and
By measuring the distance between the second position and the second position, the burying depth of the buried object can be specified.

According to the present invention, at least two receiving antennas having the same directional characteristics are provided. When the end of the buried object is positioned between the two receiving antennas in a direction orthogonal to the virtual plane including the two receiving antennas, there is a large difference between the reception strengths of the two receiving antennas. Occurs. This makes it possible to reliably detect the end of the buried object. Such detection of the end of the buried object is the same for a portion extending in a direction different from the estimated extending direction. Thereby, when the buried object detector is arranged such that the two receiving antennas can receive the electromagnetic wave from the portion extending in the estimated extending direction, the end of this portion is specified, and the extending direction is determined. When the buried object detector is placed in a state where it can receive electromagnetic waves from a portion extending in a direction different from the direction, the end of this portion can be characterized. Therefore, the end, the bent position, and the branch position of the buried object can be reliably specified.

In particular, in the configuration of the invention described in claim 2,
Providing at least two receiving antennas having directional characteristics in one of the X direction and the Y direction makes it easy to specify the buried position of the buried object when the buried object is T-shaped or L-shaped. . Furthermore, by arranging at least two receiving antennas each having a directional characteristic in both the X direction and the Y direction,
In the case of the letter shape and the L shape, the embedded position of the embedded object can be reliably and easily specified.

Further, according to the present invention, a receiving antenna capable of arbitrarily changing the direction of the directivity is provided. In locating the buried object by searching the ground while moving the buried object detector in the supposed direction of the buried object, the buried object extends in a direction different from the extending direction of the buried object. When a part is detected, the direction of the directional characteristic of the receiving antenna can be arbitrarily changed, and the direction of the directional characteristic of the receiving antenna is changed. By specifying the direction of the characteristic, the extending direction of the portion extending in the different direction can be estimated. Further, when specifying the embedding position of the portion extending in the extending direction of the buried object, when it is predicted in advance that there is a portion extending at a predetermined angle with respect to the extending direction, By changing the directional characteristics in the direction in which the reception intensity of electromagnetic waves from that part becomes the highest, and then moving the buried object detector to search underground, it is possible to reliably detect parts extending in different directions. it can.

[Brief description of the drawings]

FIG. 1 is a front view illustrating a main configuration of a receiving unit 2 provided in an embedded object detector 1 according to an embodiment of the present invention.

FIG. 2 is a plan view showing a main configuration of the receiving means 2 as viewed from above in FIG.

FIG. 3 is a perspective view showing an embedded object detector 1;

FIG. 4 is a diagram for explaining the directional characteristics of a bar antenna.

FIG. 5 is a diagram for explaining the directional characteristics of a bar antenna.

FIG. 6 shows the shape of the buried pipe 3 and each antenna X1, X2; Y.
FIG. 3 is a diagram for explaining an example of the relationship between the reception intensity of Y1 and Y2.

FIG. 7 shows each of the antennas X1 and X when the buried pipe 3 is detected.
FIG. 2 is a diagram showing an example of a change in reception strength of Y1 and Y2.

FIG. 8 is a diagram for explaining a procedure for specifying a bending position 20 of the buried pipe 3;

FIG. 9 is a diagram for explaining a procedure for specifying the burial depth of the buried pipe 3;

FIG. 10 is a diagram illustrating an example of a change in reception intensity of each of the antennas X2 and Z when a search for specifying the burial depth of the buried pipe 3 is performed.

FIG. 11 shows a buried object detector 1A according to another embodiment of the present invention.
FIG. 4 is a front view showing a main configuration of the receiving means 2A.

12 is a plan view showing a main configuration of a receiving unit 2A of the buried object detector 1A as viewed from above in FIG. 11;

FIG. 13 is a diagram illustrating an example of a change in reception intensity by each of the antennas X1, X2, and YA when the buried pipe 3 having the shape illustrated in FIG. 6 is detected.

[Explanation of symbols]

 1, 1A buried object detector 2, 2A receiving means 3 gas pipe 15 processing means 16 display means X1, X2; Y1, Y2; Z; YA receiving antenna

Claims (5)

[Claims] 1. A buried object detector for generating a current in a buried object buried in a concealed place and receiving an electromagnetic wave radiated from the buried object by a receiving antenna to detect the buried object. A buried object detector comprising a plurality of receiving antennas each having a directional characteristic in a direction. 2. The buried object detector according to claim 1, wherein at least two of the plurality of receiving antennas have directional characteristics selected in an X direction and a Y direction orthogonal to each other. 3. The antenna according to claim 2, wherein at least one of the plurality of reception antennas has a directional characteristic selected in a Z direction orthogonal to the X direction and the Y direction.
A buried object detector as described. 4. The buried object detector according to claim 1, wherein at least two of the plurality of receiving antennas have directional characteristics selected in the same direction. 5. The buried object detector according to claim 1, wherein at least one of the plurality of receiving antennas can arbitrarily change a direction of a directional characteristic.