JPH09229612A - Position detection device for buried object - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve accuracy of position detection. SOLUTION: This device detects the position of a buried object by comparing output of a pair of magnetic sensors 1a, 1b detecting magnetism of a permanent magnet 4 provided on the buried object 3 which is covered with a concealing object such as wall material 5. Both magnetic sensors 1a, 1b are arranged at an interval so that the output curves of the magnetic sensors 1a, 1b intersect in the vicinity of the inflection point in the characteristic of the curve for the outputs versus the distance of the respective sensors 1a, 1b from the permanent magnet 4. The output of the magnetic sensors can be set to be not so small when the permanent magnet is positioned in the vicinity of the middle point of both magnetic sensors, and output difference of both magnetic sensors can be set large against very small dislocation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention nondestructively detects, from the wall surface, an embedded object located behind a wall or the like, particularly an embedded object such as an outlet box or a switch box hidden by a wall material when building a house. The present invention relates to a position detecting device for an embedded object.

[0002]

2. Description of the Related Art At the time of building a house, an embedded object such as an outlet box or a switch box is embedded in a wall in advance, and an interior wall material is pasted, so that the embedded object is once hidden behind the wall material. For this reason, when using an embedded object, it is necessary to detect the position of the embedded object and expose a hole in the wall material to expose the embedded object. Is provided.

As shown in FIG. 2, this is to detect the position of the buried object 3 by detecting the magnetism of the permanent magnet 4 previously mounted on the buried object 3 from the surface of the wall member 5. The detection device is provided with a pair of left and right magnetic sensors 1a and 1b and a pair of upper and lower magnetic sensors 1c and 1d.
A display means is provided on the surface of the detection device, and a total of five light emitting display elements 2a, 2b, 2c, 2d, 2e of 4 + 1 are shown in the figure.
Is provided. The pair of left and right magnetic sensors 1a, 1a
The distance from the center point where the line connecting b and the line connecting the pair of upper and lower magnetic sensors 1c and 1d intersect to the magnetic sensors 1a and 1b is equal, and the distance from the center point to the magnetic sensors 1c and 1d is also the same. They are equal.

The magnetic distribution MF of the permanent magnet 4 behind the wall member 5 is as shown in FIG.
If the magnetic force values Ma and Mb detected by a, 1b or the magnetic sensors 1c, 1d are equal, the pair of magnetic sensors 1a, 1b
It can be seen that there is a permanent magnet 4 behind the midpoint of b or 1c, 1d. If the magnetic force values Ma and Mb are different, the detection device is moved to the magnetic sensor side that has detected a high magnetic force value, so that the intermediate point of the pair of magnetic sensors 1a, 1b or 1c, 1d is directly above the permanent magnet 4. Can be located at.

For this reason, in the illustrated example, when the center point is directly above the permanent magnet 4, the central light emitting display element 2e is turned on, and when the center point is not directly above the permanent magnet 4, the detected magnetic force value Ma, Depending on the difference in Mb, one or two of the four light emitting display elements 2a, 2b, 2c, 2d are turned on and the detector is moved in either direction, the center point of which is positioned directly above the permanent magnet 4. You can see what you can do.

FIG. 3 is a block circuit diagram of this detection apparatus. Each magnetic sensor 1a, 1b, 1c, 1d is connected to a control circuit 7 composed of a microcomputer via amplifiers 6a, 6b, 6c, 6d, respectively. The position of the permanent magnet 4 (position of the buried object) is detected by the above algorithm, and the light emitting display elements 2a, 2b, 2c, 2d, 2 are detected according to the detection result.
Turn on e.

[0007]

Here, when the hole is made in the wall material after the position of the buried object is detected to expose the buried object, a hole of a size required by the electric hole saw may be opened at a stretch. It is supposed to be done,
In order to deal with this, the permanent magnet mounted on the buried object is located at the center point of the buried object.

Along with this, the position detecting device for the buried object is also
There is a demand for an object that has not only the position of the permanent magnet but also the accuracy of the center of the permanent magnet. The present invention has been made in view of such a point, and an object thereof is to provide a position detecting device for an embedded object with high position detection accuracy.

[0009]

SUMMARY OF THE INVENTION The present invention, however, compares the outputs of a pair of magnetic sensors for detecting the magnetism of a permanent magnet provided in a buried object at the position of the buried object covered with a cover such as a wall material. A device for detecting the position of an embedded object obtained by the method, wherein both magnetic sensors are arranged at an interval where the output curves of the pair of magnetic sensors intersect in the vicinity of the inflection point in the distance-output characteristic of each magnetic sensor from the permanent magnet. This is characterized in that the output of the magnetic sensor does not become too small when the permanent magnet is near the midpoint of both magnetic sensors, and the output difference of both magnetic sensors with respect to a minute position shift is small. It is designed to be large.

[0010]

DETAILED DESCRIPTION OF THE INVENTION Magnetic sensors 1a, 1b, 1c,
The arrangement of 1d, the display means, and the configuration such as position detection and movement direction display are the same as those shown in the above-mentioned conventional example, and therefore the description thereof will be omitted. However, in the present invention, the interval between the paired magnetic sensors 1a, 1b is arranged. The arrangement interval L'of L and the magnetism 1c, 1d is determined as follows, and this interval L, L '
Then, magnetic sensors 1a, 1b and 1c, 1d are provided.

That is, the output of the magnetic sensor (output voltage after amplification by the amplifier) and the horizontal distance from the magnetic sensor to the permanent magnet form a correlation curve as shown in FIG. 1 (a). The output gradually decreases as the magnetic sensor moves away from the center of the permanent magnet, and the amount of change in the output value with respect to the distance at this time gradually increases as the magnetic sensor moves away from the center of the permanent magnet. To gradually become smaller. The point at which the increasing / decreasing tendency of the amount of change changes is the inflection point a. When installing the pair of magnetic sensors 1a and 1b, both magnetic sensors 1a and 1b having the same output characteristics are used. , Both magnetic sensors 1a, 1
The interval L of b is determined so that the output curves of the magnetic sensors 1a and 1b intersect at the inflection point a. That is,
In FIG. 1 (a), the distance L is set to a value twice the distance M from the center of the permanent magnet to the inflection point a.

When the distance L is set in this way, the permanent magnets are arranged on both magnetic sensors 1a and 1b as compared with the case where the magnetic sensors 1a and 1b are arranged at an interval shorter than the distance L.
Both magnetic sensors 1a, 1b when located near the midpoint of
Of the magnetic sensor 1a, 1b at a longer interval than the interval L described above.
In comparison with the case where the permanent magnets are arranged, the permanent magnets have both magnetic sensors 1.
Both magnetic sensors 1 when located near the midpoint between a and 1b
It is possible to obtain high level output values of a and 1b, and it is possible to perform position detection that is not affected by noise.

Of course, the distance L'between the pair of magnetic sensors 1c and 1d is set as described above.

[0014]

As described above, in the present invention, both magnetic sensors are arranged at an interval where the output curves of the pair of magnetic sensors intersect in the vicinity of the inflection point in the distance-output characteristic of each magnetic sensor from the permanent magnet. Therefore, the output of the magnetic sensor when the permanent magnet is near the midpoint of both magnetic sensors does not become too small to be buried in noise. Since the output difference of the sensor becomes large, the position detection accuracy is high.

[Brief description of drawings]

FIG. 1 illustrates the present invention, (a) is an explanatory view of output characteristics of a magnetic sensor according to a distance from a permanent magnet, and (b).
FIG. 6 is an explanatory diagram of an arrangement interval of a pair of magnetic sensors.

FIG. 2 is a cutaway perspective view showing a schematic configuration of a buried object position detection device.

FIG. 3 is a block circuit diagram of the same.

FIG. 4 shows an algorithm for position detection of the above.
(a) (b) (c) is operation explanatory drawing, respectively.

[Explanation of symbols]

 1a, 1b, 1c, 1d Magnetic sensor 3 Embedded object 4 Permanent magnet

Claims (1)

[Claims] 1. A position detecting device for a buried object which is obtained by comparing the outputs of a pair of magnetic sensors for detecting the magnetism of a permanent magnet provided in the buried object with the position of the buried object covered with a cover material such as a wall material. Position detection of the buried object, characterized in that both magnetic sensors are arranged at an interval where the output curves of the pair of magnetic sensors intersect near the inflection point in the distance-output characteristic of each magnetic sensor from the permanent magnet. apparatus.