JPS6022310B2 - Underground object detection device - Google Patents

Description

[Detailed description of the invention] When boring a road etc. where underground objects such as gas pipes and water pipes are buried in a wide area, the following method is used with reference to the underground installation map. We tried to avoid the buried area when drilling, but depending on the construction work, it is often necessary to drill close to the buried area, and the location indicated on the burial distribution map and the actual underground buried item often have to be drilled. There was a large discrepancy between the buried objects and the buried objects, and during boring, the bit of the boring equipment came into contact with underground objects, often causing serious accidents.

The present invention relates to an underground object detection device for preventing such accidents, and as shown in the diagram corresponding to the claims related to the present invention in FIG. A grounding resistance C formed by a grounding wire B buried in a location where the grounding resistance C is formed, one constant resistance D having an inverse proportional relationship to the grounding resistance C, and two variable resistances E having a proportional relationship.
and F, a dummy variable resistor 1 switch-connected in parallel to the grounding resistor C via a dummy changeover switch to the grounding portion of the boring device A, and the grounding resistor B. The same Earth Hayabusa B as a reference
and the potential of the other end of the variable resistor E connected to the grounding part of the boring device A of the grounding resistor C, which is also based on the grounding wire B, or the end of the dummy variable resistor 1 connected to the grounding wire B. A zero point detection meter J that detects a potential difference between potentials, a comparison circuit L that is switched and connected in parallel to the zero point detection meter via a bridge changeover switch K to the dummy changeover switch part, and an output of the comparison circuit L. The comparator circuit L operates as follows.
The device is characterized in that one of the two potentials is set to a predetermined value by a variable resistor E, and a change in the other potential is detected when the change in the other potential reaches the predetermined value.

Since the present invention is configured as described above, in a state where the bridge changeover switch K is switched and connected to the zero point detection meter J of the bridge circuit G, the dummy changeover switch is first connected to the boring machine A, and the Adjust the variable resistors E and F appropriately to set the zero point detection meter J to a state where it shows the zero scale, then connect the dummy changeover switch to the dummy variable resistor 1 side, and set the zero point detection meter J to the zero scale. By adjusting the dummy variable resistor 1 so as to indicate the zero scale, the initial resistance value of the grounding resistor C can be replaced with the dummy variable resistor 1, and based on the resistance value, when the boring equipment approaches the buried object. Determine the resistance value of Next, connect the bridge changeover switch K to the comparator circuit L side, set the dummy variable resistor to the resistance value determined as above, with the dummy changeover switch mark connected to the dummy variable resistor 1 side, and set the dummy variable resistor to the resistance value determined as above. The variable resistor E is appropriately adjusted to a state where the motor starts operating.

After completing the preparations in this way, the bridge selector switch K
When the dummy changeover switch is switched to the boring equipment A side while leaving the dummy changeover switch as it is, "When the potential of the grounding part of the boring equipment A with reference to the ground B decreases and becomes lower than the potential of one end of the adjusted variable resistor E. Comparator circuit J detects this, and the detection signal can operate relay M. If the alarm device is activated by the operation of this relay, the tip bit of the boring device approaches underground objects. As described above, according to the present invention, changes in the ground resistance formed by the grounding part of the boring machine and the grounding rod buried at a predetermined distance away are detected. There is no need to directly connect the terminal to a part of the existing conductive buried object, and the initial connection does not require much effort.

In addition, a bridge circuit consisting of one constant resistor having an inversely proportional relationship with the grounding resistance and two variable resistors having a proportional relationship, and a dummy changeover switch connected to the grounding part of the boring device are connected in parallel to the grounding resistance. a dummy variable resistor that is switched and connected, the potential of the other end of the variable resistor connected to the ground bar with the ground bar as a reference, and the grounding of the boring device of the ground resistor also with the ground bar as a reference. Since it has a grounding resistance measuring circuit consisting of a zero point detection meter that detects the potential difference between the potential at the other end of the dummy variable resistor connected to the grounding section or the grounding device, the grounding section of the boring machine and the grounding device are initially The ground resistance, including the properties of the soil and the condition of buried objects, can be measured directly by replacing it with a dummy variable resistor without calculating the bridge circuit. It is assumed that it can be dealt with.

Further, the dummy changeover switch portion is provided with a comparison circuit that is switched and connected in parallel to the zero point detection meter via a bridge changeover switch, and a relay that is operated by the output of the comparison circuit. One of the two input potentials is set to a constant value based on the measured initial ground resistance value by a variable resistor connected to the ground rod, and the change in ground resistance due to starting boring is controlled. It is configured to detect the change in the other potential and compare it with the above-mentioned constant value to detect when the potential difference becomes zero, so the rod advances due to the drive of the boring device and approaches the underground object. By setting the comparator circuit so that the reduction in ground resistance reaches a certain value at the previous safe position, the relay can be operated when the reduction in ground resistance reaches a certain value.

This relay operation stops the driving of the boring machine and issues an alarm, allowing the boring work to be carried out safely.

Furthermore, as mentioned above, the grounding resistance of the ground where the ground is bored varies greatly depending on the location, but the present invention measures the grounding resistance for the first time and sets a comparison circuit based on that value. It is possible to overcome differences in conditions due to different locations and provide a highly reliable detection device.

Furthermore, the state change in which the boring equipment is driven and the rod approaches the underground object can be simulated using a dummy resistor, so reliability can be improved by testing whether or not the specified operation is actually performed. It can be further increased.

One embodiment of the present invention shown in the drawings will be described below. Reference numeral 1 denotes one sensor input terminal connected to a drilling pipe of a boring machine (not shown), and is located at a point approximately 10 skins away horizontally from the drilling pipe. The other sensor input terminal 2 is connected to a grounding rod (not shown) that is driven into the ground approximately one inch.

In addition, the bridge circuit 3 has one plate 0 and 2000 variable resistors 4.
, 5 and 6. It consists of a variable resistor 7 in which a fixed resistor 6 with a resistance of 0 and variable resistors 7a and 7b with an IKQ of 2000 are connected in series, and a zero point detection meter 8.The input terminal of the variable resistor 4 is connected to the sensor input terminal 1. and the input terminal of the variable resistor 5, and the input terminal of the zero point detection meter 8 and the 50KQ resistor 1.
The bridge switching switch 10 is selectively connected to one of the other input terminals of the operational amplifier 13 via the bridge switching switch 10.

Furthermore, the connection between the resistors 6 and 7, which are the output terminals of the bridge circuit 3, is connected to one input terminal of the operational amplifier 13 via a 100KQ resistor 11.

In addition, both terminals of the zero point detection meter 8 and both input terminals of the operational amplifier 13 are connected to protection circuits 14 and 15 each consisting of a pair of diodes connected in parallel in opposite directions. Also, a fixed resistor 16 of 10 mm connected to one input terminal of the operational amplifier 13, a fixed resistor 17 of 350 KO connected to the output terminal of the operational amplifier 13, and a variable resistor 18 of 1 connected to the ground terminal 2. A sensitivity adjustment circuit 19 is formed.

Furthermore, the output terminal of the operational amplifier 13 is connected to a relay driving transistor 22 via a resistor 20 and a diode 21 of one plate Q.
The transistor 22 for driving the relay is connected to the base of the relay.
is connected to the relay 23 in series.

Furthermore, a power indicator lamp 24 is connected in parallel with the relay 23 and the relay driving transistor 22.

Therefore, the power supply for the bridge circuit 3 and the relay 23 is 2
A constant voltage power supply circuit 29 consisting of transistors 25 and 26, a diode 27, and a resistor 28 having an arc ◯ is connected to a 12 V DC voltage terminal via a power switch 30 and a fuse 31.

Further, an alarm buzzer 32 and an alarm indicator light 33 are connected to a 12V DC battery (not shown) via a buzzer release switch 34, a connection 23a of the relay 23, and a power switch 30, and a 24V DC voltage is applied to the operational amplifier 13. It has become so.

Note that 34' and 35 are battery voltage detection meters and their push-pin switches. Since the illustrated embodiment is configured as described above, when the dummy changeover switch 9 is connected to one sensor input terminal 1, the bridge changeover switch 10 is connected to the zero point detection meter 8, and the zero point detection meter 8 is connected to the bridge changeover switch 10. The variable resistors 7a and 7b are appropriately operated so that the scale becomes 0.

When this operation is completed, the resistance value YE of the grounding resistor is YE=Etomu Y6 where Y4, Y8 and Y7 are the resistance values of resistors 4, 6, and 7, respectively.

Next, after connecting the dummy changeover switch 9 to the input terminal of the variable resistor 5, operate the variable resistor 5 appropriately so that the scale of the zero point detection meter 8 becomes 0 in the same way as described above. If you read the resistance scale, the resistance value Y of the grounding resistance
You can know E.

The ground resistance in the ground of normal soil is about 300.

Then, with the dummy changeover switch 9 connected to the input terminal of the variable resistor 5, the bridge changeover switch 10 is connected from the zero point detection meter 8 to the other input terminal of the operational amplifier 13, and then the resistance value that can be found just now is obtained. A dummy variable resistor is set to a value of about 70% to 80% of Y8, and then the reference input potential of one side of the operational amplifier 13 is adjusted appropriately with the variable resistor 7 to reach 70% of the resistance value YE.
The 1'' relay 23 is made to operate at a set value of about % to 80%. Preparation is completed by setting the variable resistor 7 in this way, but the actual resistance value Yo is 70% to 8%.
The relay operates at the set value of about 0%, and to see if the alarm is activated, gradually decrease the dummy variable resistor 5 from the maximum value and check the resistance value of the dummy variable resistor 5 when the alarm sounds. , it's safe if you check.

After such detection preparations are completed, the bridge selector switch 10 is connected to the other input terminal of the increase circuit 13).
, the gummy changeover switch 9 is switched and connected from the input terminal of the variable resistor 5 to one of the sensor input terminals 1, a boring device (not shown) is operated, and the excavation pipe is brought into the ground.

In the unlikely event that the tip of the excavation pipe approaches an underground object, the resistance value YE of the earthing resistance will rapidly decrease, and when it falls below the set earthing resistance value, the output of the operational amplifier 13 will be at a negative potential. The potential changes from to positive, and the relay driving transistor 2
2 becomes the conductive state, the relay 23 is operated, and the operation of the relay 23 closes the relay A contact 23a, the alarm buzzer 32 sounds, and the alarm indicator light 33 lights up, thus making it possible to know the dangerous situation. .

If the operation of the boring equipment (not shown) is immediately stopped when such a warning is issued, damage to underground objects can be prevented.

Therefore, by using the above embodiment, even in places where various types of underground objects are buried, the boring work can be carried out reliably without damaging the underground objects.

Normally, as the excavation pipe penetrates deeper into the ground, the resistance value Y8 of the ground resistance gradually decreases, so the resistance value Y8 of the variable resistor 4 gradually decreases.
If the variable resistor 4 is configured so that the resistance value YE of the variable resistor 4 is changed in conjunction with changes in the excavation depth so that E is balanced with the ground resistance value YE, even if the underground object is buried deeply. , it is possible to reliably detect when the tip of the excavation pipe approaches the underground object.

Further, if the construction is such that when the relay 23 is activated, the operation of the boring device (not shown) is automatically stopped, damage to underground objects can be more reliably prevented.

Although the present invention has been specifically described above with respect to the above-mentioned embodiments, the present invention is not limited to such embodiments.
Design changes can be made freely as necessary.

[Brief explanation of the drawing]

FIG. 1 is a diagram corresponding to the claims of the present invention, and FIG. 2 is a circuit diagram illustrating an embodiment of the underground object detection device according to the present invention. 1... One sensor input terminal, 2... Other sensor input terminal, 3... Bridge circuit, 4,
5...Variable resistance, 6...Fixed resistance, 7...
...Variable resistance, 8...Zero point detection meter, 9
...Dummy changeover switch, 10...Bridge changeover switch, 11,12...Resistance, 13.
...Operation amplifier, 14,15...Protection circuit,
16, 17...Fixed resistor, 18...Variable resistor, 19...Sensitivity adjustment circuit, 20...
Resistor, 21...Diode, 22...
Relay driving transistor, 23...Relay, 24
...Power indicator lamp, 25, 26...Transistor, 27...Diode, 28...Resistor, 29...Constant voltage power supply circuit, 30...・・・
Power switch, 31...・Fuse, 32...
...Alarm buzzer, 33...Warning indicator light, 34
...Buzzer release switch, 34'...Battery voltage detection meter, 35...Push nail switch. Figure 1 Figure 2

Claims (1)

[Claims] 1 Consists of a grounding resistance formed by the grounding part of the boring machine and a grounding rod buried at a predetermined distance from the grounding device, one constant resistance that is inversely proportional to the grounding resistance, and two variable resistances that are proportional to the grounding resistance. a dummy variable resistor connected in parallel to the grounding resistor via a dummy changeover switch to the grounding portion of the boring device; zero point detection for detecting a potential difference between the potential at the other end of the variable resistor and the potential at the other end of the dummy variable resistor connected to the grounding portion of the boring device of the grounding resistor or the grounding bar, which is also based on the grounding bar; The comparator circuit comprises a meter, a comparator circuit connected to the dummy selector switch in parallel to the zero point detection meter via a bridge selector switch, and a relay operated by the output of the comparator circuit. One of the two input potentials is set to a predetermined value by a variable resistor connected to the earth rod, and a case is detected when a change in the other potential reaches the predetermined value. An underground object detection device.