JP3582208B2 - Buried object position detection device - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an embedded object position detecting device for non-destructively detecting an embedded object located behind a wall or the like, particularly an embedded object such as an outlet box or a switch box, which is hidden by a wall material when building a house, from a wall surface. Things.
[0002]
[Prior art]
When constructing a house, a buried object such as an outlet box or a switch box is buried in a wall in advance, and then the buried object is temporarily hidden behind the wall material in order to attach an interior wall material. Therefore, when using a buried object, it is necessary to detect the position of the buried object, make a hole in the wall material and expose the buried object, and use magnetism to detect the position of this buried object. Is provided.
[0003]
As shown in FIG. 2, the position of the buried object 3 is detected by detecting the magnetism of the permanent magnet 4 previously mounted on the buried object 3 from the surface of the wall material 5. Are 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, and display means on the surface of the detecting device, in the illustrated case, a total of five (4 + 1) light emitting display elements 2a and 2b. , 2c, 2d, 2e. The distance from the center point where the line connecting the pair of left and right magnetic sensors 1a and 1b and the line connecting the pair of upper and lower magnetic sensors 1c and 1d intersects the magnetic sensors 1a and 1b. The distances to the magnetic sensors 1c and 1d are also equal.
[0004]
The magnetic distribution MF of the permanent magnet 4 behind the wall member 5 is as shown in FIG. 4, but if the magnetic force values Ma and Mb detected by the paired magnetic sensors 1a and 1b or the magnetic sensors 1c and 1d are equal, the pair is It can be seen that the permanent magnet 4 exists behind the intermediate point of the magnetic sensors 1a, 1b or 1c, 1d. If the magnetic force values Ma and Mb are different, the detecting device is moved to the magnetic sensor that has detected the high magnetic force value, so that the intermediate point of the pair of magnetic sensors 1a, 1b or 1c, 1d is located immediately above the permanent magnet 4. Can be located.
[0005]
For this reason, in the illustrated embodiment, the central light emitting display element 2e is turned on when the center point is directly above the permanent magnet 4, and when the center point is not directly above the permanent magnet 4, the difference between the detected magnetic force values Ma and Mb is determined. If one or two of the four light emitting display elements 2a, 2b, 2c, and 2d are turned on in accordance with the above and the detection device is moved in either direction, the center point thereof can be located directly above the permanent magnet 4. The display indicates whether it is possible.
[0006]
FIG. 3 is a block circuit diagram of the detection device. 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 (the position of the embedded object) is detected, and the light emitting display elements 2a, 2b, 2c, 2d, and 2e are turned on according to the detection result.
[0007]
[Problems to be solved by the invention]
Here, in opening a hole in the wall material after detecting the position of the buried object and exposing the buried object, a hole of a size required by the electric hole saw is to be made at a stretch, In order to cope with this problem, the permanent magnet mounted on the buried object is located at the center point of the buried object.
[0008]
Accordingly, a device for detecting the position of a buried object is required to have not only the position of the permanent magnet but also the accuracy with which the center of the permanent magnet can be determined.
The present invention has been made in view of such a point, and an object of the present invention is to provide an apparatus for detecting the position of an embedded object having high position detection accuracy.
[0009]
[Means for Solving the Problems]
Thus, the present invention relates to a position detecting device for a buried object which determines the position of the buried object covered with a concealing object such as a wall material by comparing the outputs of a pair of magnetic sensors for detecting the magnetism of a permanent magnet provided in the buried object. There is a feature that 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, The output of the magnetic sensor when the permanent magnet is located near the midpoint between the two magnetic sensors is prevented from becoming too small, and the output difference between the two magnetic sensors with respect to a minute displacement is increased.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
The arrangement of the magnetic sensors 1a, 1b, 1c, 1d and the display means, and further the configuration such as the position detection and the movement direction display are the same as those shown in the above-mentioned conventional example, so they are omitted, but they are a pair in the present invention. The arrangement interval L between the magnetic sensors 1a and 1b and the arrangement interval L 'between the magnets 1c and 1d are determined as follows, and the magnetic sensors 1a, 1b and 1c and 1d are provided at the intervals L and L'.
[0011]
That is, the output of the magnetic sensor (the output voltage after amplification by the amplifier) and the horizontal distance from the magnetic sensor to the permanent magnet draw a correlation curve as shown in FIG. The output gradually decreases as the magnetic sensor moves away from the center of the permanent magnet. From then roll down gradually. The inflection point a is where the increasing / decreasing trend of the change amount changes. When the paired magnetic sensors 1a and 1b are installed, both magnetic sensors 1a and 1b use the same output characteristics. The distance L between the two magnetic sensors 1a and 1b is determined so that the output curves of the two magnetic sensors 1a and 1b intersect at the inflection point A. That is, the distance L is set to a value twice the distance M from the center of the permanent magnet to the inflection point A in FIG.
[0012]
When the interval L is set in this way, compared with the case where the magnetic sensors 1a and 1b are arranged at intervals shorter than the interval L, the time when the permanent magnet is located near the intermediate point between the two magnetic sensors 1a and 1b is reduced. The value of the difference between the output values of the two magnetic sensors 1a, 1b can be increased, and the detection accuracy of the center of the permanent magnet can be increased. In addition, the magnetic sensors 1a, 1b are arranged at intervals longer than the interval L. 1b, the output value of the two magnetic sensors 1a, 1b can be higher when the permanent magnet is located near the midpoint between the two magnetic sensors 1a, 1b. Position detection without being affected can be performed.
[0013]
Of course, the distance L 'between the pair of magnetic sensors 1c and 1d is also set as described above.
[0014]
【The invention's effect】
As described above, in the present invention, since both magnetic sensors are arranged at intervals 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, When the permanent magnet is near the midpoint between the two magnetic sensors, the output of the magnetic sensor will not be too small and will not be buried in noise. Because of the large size, the position detection accuracy is high.
[Brief description of the drawings]
FIGS. 1A and 1B are diagrams for explaining the present invention, wherein FIG. 1A is an explanatory diagram of an output characteristic of a magnetic sensor according to a distance from a permanent magnet, and FIG. 1B 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 device for detecting the position of an embedded object.
FIG. 3 is a block circuit diagram of the same.
FIG. 4 is a diagram illustrating an algorithm of position detection according to the first embodiment, and FIGS.
[Explanation of symbols]
1a, 1b, 1c, 1d Magnetic sensor 3 Buried object 4 Permanent magnet

Claims (1)

What is claimed is: 1. A position detecting device for a buried object, wherein the position of the buried object covered by a concealing object such as a wall material is determined by comparing the outputs of a pair of magnetic sensors for detecting the magnetism of a permanent magnet provided in the buried object. Wherein the two magnetic sensors are arranged at intervals where the output curves of the pair of magnetic sensors intersect in the vicinity of the inflection point in the distance-output characteristic from the permanent magnet.

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