JP3644120B2 - Embedded object position detection device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a buried object position detecting device that non-destructively detects a buried object such as an outlet box or a switch box concealed by a wall material at the time of building a house from the wall surface. Is.
[0002]
[Prior art]
At the time of building a house, an embedded object such as an outlet box or a switch box is embedded in the wall in advance, and then the embedded object is once hidden behind the wall material in order to attach an interior wall material. For this reason, when using the embedded object, it is necessary to detect the position of the embedded object and make a hole in the wall material to expose the embedded object. Is provided. That is, a permanent magnet is mounted on the buried object in advance, and the position of the buried object is detected by detecting the magnetism of the permanent magnet from the surface of the wall material.
[0003]
[Problems to be solved by the invention]
Here, it is possible to detect the embedded object even if the embedded object (permanent magnet) is far away if the magnetic detection sensitivity is set high. In this case, a position detection device is installed near the embedded object. When positioned, it is difficult to accurately detect the position due to oversensitivity. Conversely, if the sensitivity is lowered, it becomes impossible to detect where the buried object is located when the buried object is away.
[0004]
For this reason, in the past, sensitivity adjustment was made possible by the user operating the volume, but the operation was cumbersome and had to be adjusted repeatedly. It was time-consuming.
The present invention has been made in view of these points, and an object of the present invention is to provide a position detection device for an embedded object capable of quickly performing highly accurate position detection.
[0005]
[Means for Solving the Problems]
Accordingly, the present invention provides a position detection device for a buried object obtained from an output of a magnetic sensor for detecting the magnetism of a permanent magnet provided on the buried object, the position of the buried object covered with a concealed object such as a wall material. It is characterized in that it has sensitivity switching means for automatic sensitivity switching that lowers the sensitivity when the magnetic level detected by the sensor is high and increases the sensitivity when the detected magnetic level is low . The sensitivity is automatically switched according to the detected magnetic level.
[0006]
The sensitivity switching means in this case may change the threshold range for position determination based on the magnetic sensor output, or may change the amplification factor of the magnetic sensor output amplification circuit.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
As shown in FIG. 2, this buried object position detecting device detects the position of the buried object 3 by detecting the magnetism of the permanent magnet 4 previously attached to the buried object 3 from the surface of the wall material 5. A pair of left and right magnetic sensors 1a and 1b and a pair of upper and lower magnetic sensors 1c and 1d are provided, and display means is provided on the surface of the detection device. A total of five light emitting display elements 2a, 2b, 2c, 2d, and 2e are provided. The distance from the central 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 intersect is equal to the magnetic sensor 1a and 1b. The distances to the magnetic sensors 1c and 1d are also equal.
[0008]
The magnetic distribution MF of the permanent magnet 4 behind the wall material 5 is as shown in FIG. 3, but if the magnetic force values Ma and Mb detected by the pair of magnetic sensors 1a and 1b or the magnetic sensors 1c and 1d are equal, It can be seen that the permanent magnet 4 exists behind the intermediate point of the magnetic sensors 1a, 1b or 1c, 1d. Further, if the magnetic force values Ma and Mb are different from each other, the detection device is moved to the side of the magnetic sensor 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.
[0009]
Therefore, the center point is directly above the permanent magnet 4, the magnetic values Ma and Mb detected by the pair of magnetic sensors 1a and 1b are equal, and the magnetic values Ma and Mb detected by the pair of magnetic sensors 1c and 1d are equal. If they are equal, the central light emitting display element 2e is turned on. When the center point is not directly above the permanent magnet 4, the four light emitting display elements 2a, 2b, 2c, 2d are selected according to the difference between the detected magnetic force values Ma, Mb. One or two of them are turned on to display in which direction the detection device can be moved to position the center point directly above the permanent magnet 4. One of the light emitting display elements 2c and 2d is turned on when the permanent magnet 4 is shifted up and down, and one of the light emitting display elements 2a and 2b is turned on when it is shifted left and right, and shifted up and down and left and right. When one of the light-emitting display elements 2a and 2b and one of the light-emitting display elements 2c and 2d are turned on at the same time, it is displayed that the moving direction should be an oblique direction.
[0010]
FIG. 4 shows a block circuit diagram. The first stage amplifiers 6a, 6b, 6c, 6d are connected to the magnetic sensors 1a, 1b, 1c, 1d, respectively, and the outputs of the first stage amplifiers 6a, 6b, 6c, 6d are respectively automatic offset adjustment circuits 7a, 7b, 7c, 7d. The outputs of the automatic offset adjustment circuits 7a and 7b for the pair of magnetic sensors 1a and 1b are input to the control circuit 9 composed of a microcomputer via the differential amplifier 8a, and the outputs of the pair of magnetic sensors 1c and 1d are as well. The outputs of the automatic offset adjustment circuits 7c and 7d are input to the control circuit 9 via the differential amplifier 8b. The position display of the permanent magnet 4 in accordance with the difference between the detected magnetic force values Ma and Mb indicates the comparison output of the output of the pair of magnetic sensors 1a and 1b by the differential amplifier 8a and the output of the pair of magnetic sensors 1c and 1d. The comparison output by the differential amplifier 8b is performed. If these comparison outputs are zero or within a predetermined range, it is determined that the permanent magnet 4 is located immediately below the center point, and the light emitting display element 2e is set. If it is positive or negative, it is judged that it is shifted up and down or left and right, and the moving direction is displayed by lighting the light emitting display elements 2a, 2b, 2c and 2d by the algorithm.
[0011]
Further, the control circuit 9 directly determines the distance from the absolute value to the permanent magnet 4 by directly taking in the outputs of the first stage amplifiers 6a, 6b, 6c and 6d, and the input values from the differential amplifiers 8a and 8b are equal. Even if an output indicating the above is output, if the absolute value is small, it is determined that the distance to the permanent magnet 4 is too long to determine the position. In this case, the light emitting display elements 2a, 2b, 2c, 2d, 2e is not lit.
[0012]
The automatic offset adjustment circuits 7a, 7b, 7c, and 7d absorb the characteristic differences of the magnetic sensors 1a, 1b, 1c, and 1d and the variations in the first stage amplifiers 6a, 6b, 6c and 6d to increase the position detection accuracy of the permanent magnet 4. When the power switch 11 of the detection device is turned on, the voltage output from the control circuit 9 is used to bias the outputs of the first-stage amplifiers 6a, 6b, 6c, 6d of the magnetic sensors 1a, 1b, 1c, 1d. In addition, this voltage is read by the control circuit 9, and the offset voltage is automatically adjusted by adjusting the bias voltage output from the control circuit 9 in accordance with the comparison result between the read value and the set voltage.
[0013]
The control circuit 9 directly takes in the outputs of the first stage amplifiers 6a, 6b, 6c and 6d and performs automatic sensitivity switching from the absolute values. That is, as shown in FIG. 1, it is initially set on the high sensitivity side so that it is possible to know in which direction the position detection device should be moved even if the permanent magnet 4 is away. When the magnetism exceeding the preset level is detected and the sensitivity is over, it is automatically switched to the low sensitivity side, and the magnetism detection output is output for 3 seconds in the state of switching to the low sensitivity side. If not, it will return to the high sensitivity side.
[0014]
Accordingly, when detecting the position of the embedded object 3, it is on the high sensitivity side when the embedded object 3 (permanent magnet 4) is separated, but when it approaches the embedded object 3, it is automatically switched to the low sensitivity side and has high accuracy. In addition, the position can be detected at the position of the embedded object 3, and when it is away from the embedded object 3, it can be automatically switched to the high sensitivity side for detection of the next embedded object 3.
[0015]
The sensitivity switching here is a voltage range (threshold value) for determining whether or not the permanent magnet 4 is directly below depending on whether or not the comparison outputs of the differential amplifiers 8a and 8b are within a predetermined voltage range centered on zero. ), And by switching the amplification factors of the first stage amplifiers 6a, 6b, 6c, and 6d as shown in FIG.
[0016]
The sensitivity switching is not limited to the two stages as shown in FIG. 1, but may be switched to multiple stages. Further, although the initial set is set to be on the high sensitivity side, the initial set may be set to the low sensitivity side, and may be switched to the high sensitivity side if the detected magnetic level does not satisfy a predetermined level. A timer may be provided to switch to the high sensitivity side when the detected magnetic level does not satisfy the predetermined level even after a predetermined time has elapsed. Further, the movement distance when moving the position detection device along the wall material is measured by using, for example, the rotation of a ball that is brought into contact with the wall material, and the magnetic level is predetermined even when the movement distance exceeds a predetermined distance. When the level is not satisfied, it may be switched to the high sensitivity side.
[0017]
FIG. 5 shows an example of the appearance of the detection device. The housing 10 in which the light emitting display elements 2a, 2b, 2c, 2d, and 2e are arranged on the surface and the back surface is formed as a flat surface has the light emitting display element 2e. At the lighting position, the upper edge and the left and right side edges of the outer shape line coincide with the outer shape of the embedded object (switch box) 3 behind the wall material, and the outer shape of the housing 10 is traced. A line is written on the wall material, and a hole is made in the wall material based on this line to expose the front portion of the embedded object 3.
[0018]
As described above, the present invention includes sensitivity switching means for automatically switching the sensitivity that lowers the sensitivity when the magnetic level detected by the magnetic sensor is high and increases the sensitivity when the detected magnetic level is low. Since the sensitivity is automatically switched according to the magnetic level applied, it is possible to obtain both the advantages of high sensitivity and the improvement of position detection accuracy by low sensitivity, and the sensitivity is a magnetic sensor. Since it is automatically switched in accordance with the magnetic level detected in step S5 and does not require any user operation, high-accuracy position detection can be performed quickly. The detected magnetic level also changes depending on the permeability of the wall material and the presence of a magnetic material in the vicinity of the permanent magnet, but this point can also be met.
[Brief description of the drawings]
FIG. 1 is a flowchart of an example of an embodiment of the present invention.
FIG. 2 is a cutaway perspective view showing a schematic configuration of the above.
FIGS. 3A and 3B show the position detection algorithm described above, and FIGS. 3A and 3B are explanatory diagrams of operations. FIGS.
FIG. 4 is a block circuit diagram of the above.
5A is a front view of the same, and FIG. 5B is a side view of the same.
FIG. 6 is a block circuit diagram of another example.
[Explanation of symbols]
1a, 1b, 1c, 1d Magnetic sensor 3 Object 4 Permanent magnet 9 Control circuit

Claims (3)

A position detecting device buried object obtained from the output of the magnetic sensor for detecting magnetism of the permanent magnets having a position of the covered buried object in concealing of wall materials such as buried objects, magnetism detected by the magnetic sensor A position detecting device for embedded objects, comprising sensitivity switching means for automatic sensitivity switching for decreasing sensitivity when the level is high and increasing sensitivity when the detected magnetic level is low .   The position detection device for an embedded object according to claim 1, wherein the sensitivity switching means changes a threshold range for position determination based on the magnetic sensor output.   2. The position detecting device for an embedded object according to claim 1, wherein the sensitivity switching means changes an amplification factor of the amplification circuit for outputting the magnetic sensor.

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