JPH08219700A - Remote wireless blasting apparatus and receiving detonator for the same - Google Patents

Abstract

PURPOSE: To surely trigger receiving detonators disposed in blasting holes from a magnetic field generating device set sufficiently far apart from a cutting face by improving receiving capability of the receiving priming devices. CONSTITUTION: A magnetic field transmitting device in a remote wireless blasting apparatus comprises a loop antenna and an AC transmitter and is installed in a tunnel in such a manner as to be capable of being moved. A receiving coil 21 in a receiving detonator 19 is contained in an end side portion within a container case 25 and has a conductive wire 26 wound by a large number of turns to form a hollow portion 27 having a specified length and diameter and passing through a center thereof in an axial direction. The receiving coil 21 generates an electromotive force in tuning of AC magnetic field from the loop antenna. A core 28 is made of silicon steel plate and has a so-called 'crank' shape having a bend portion bent at a central portion. An explosive 24 is arranged on an extension of the receiving coil 21 and is detonated by the electromotive force of the receiving detonator 19.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a remote wireless blasting device for excavation work such as tunnels and a receiving detonator used for the remote blasting device.

[0002]

2. Description of the Related Art Conventionally, in excavation work by a blasting method such as a tunnel, explosives and detonators for electric detonators, non-electric detonators, etc. are loaded and connected in the blast holes drilled in a face. . After that, the detonator for detonation is detonated and blasted.

Further, Japanese Examined Patent Publication No. 51-12922 discloses a waterbed bedrock remote detonator as a remote detonator. That is, an ignition power supply is provided inside the receiving detonator, and an ignition signal is transmitted by an ultrasonic wave from the outside.
The receiving detonator receives the signal and detonates.

Further, Japanese Patent Publication No. 50-28621 discloses another remote blasting device. That is, in order to excavate the rock on the seabed, a loop antenna having a large diameter is arranged on the sea surface, and the receiving detonator is buried in the rock on the seabed located below the antenna surface. Then, the magnetic field generated by the loop antenna activates the receiving detonator to explode the rock mass. This publication discloses a receiving detonator having a core with a length equal to or shorter than the receiving coil length.

[0005]

However, in the charging work into the blast hole of the tunnel and the connection work with the detonator, the worker works with a face face that has a high possibility of falling stones or falling.
Take care when working. In the conventional wire-type detonation method using an electric detonator or a non-electric detonation system, it was necessary to carefully handle the leg wire and the plastic tube so as not to break the wire at the time of charging the blast hole. For this reason, it is very difficult to automate this work, and there is also a problem that it takes time and labor because the work is manually performed.

Further, since the remote detonator disclosed in Japanese Patent Publication No. 51-12922 has a power supply in the receiving detonator, it requires a complicated circuit for preventing erroneous explosion and the device is complicated. There was a problem of increasing the size. Moreover, since ultrasonic waves are used, it is necessary to install the receiving element outside the blast hole, and there is a problem that distance attenuation becomes large on land.

Furthermore, when the remote blasting device disclosed in Japanese Patent Publication No. 50-28621 is used for excavation work by a blasting method such as a tunnel or an underground space, the magnetic field of the loop antenna is weak, so that the distance attenuation is reduced. Therefore, it will be attached to the face. In this case, the magnetic field near the cable of the loop antenna is distributed almost concentrically with respect to the axial direction of the cable, so the change in the magnetic field direction is large,
There are places where a detonator that is tuned only to a magnetic field in one direction cannot be detonated. In addition, the loop antenna needs to be attached to the face each time it is blasted, which causes a problem that the loop antenna becomes disposable.

In addition, in the receiving detonator used in this remote blasting device, the length of the core is less than the receiving coil length. For this reason, if the loop antenna is installed at a sufficient distance from the face and is used for excavation work by a blasting method such as a tunnel or an underground space, the reception capability is weak,
It was necessary to upsize the receiving detonator. In general, when performing blasting, the detonator is placed in the innermost part of the blasting hole, because the explosive is placed in the blasting hole. Therefore, if the size of the receiving detonator is increased in order to improve the receiving ability, the diameter of the blast hole must be increased or extra holes must be formed for the receiving detonator, which causes a problem that workability deteriorates. It was

The present invention has been made by paying attention to such a problem of the prior art. The purpose is to
To provide a remote wireless blasting device and a receiving detonator capable of improving the receiving capability of the receiving detonator and reliably detonating the receiving detonator arranged in the blast hole from a magnetic field generator installed at a place sufficiently away from the face. It is in.

Another object of the present invention is to simplify the structure by eliminating the power supply in the receiving detonator, and to reduce the size,
It is an object of the present invention to provide a remote wireless blasting device and a receiving detonator that can be reduced in weight.

Another object is to eliminate the need for a power source such as a battery in the receiving and detonating unit, to transmit the detonating energy to the explosive immediately before the blasting, and to eliminate the risk of accidental explosion. It is an object of the present invention to provide a remote wireless blasting device and a receiving detonator capable of reducing work to be performed and improving workability.

[0012]

In order to achieve the above object, in the invention of the remote wireless blasting apparatus according to the first aspect,
The magnetic field generator comprises a receiving detonator, the magnetic field generator comprises an AC oscillator that generates an alternating current of a specific frequency, and an antenna that generates a magnetic field by the alternating current, the receiving detonator is a hollow portion. A receiving coil having a core, a core arranged in the hollow portion of the receiving coil, a receiving circuit connected to the receiving coil, and an explosive which is detonated by energy from the receiving circuit, and the explosive on an extension line in the axial direction of the receiving coil. And the core is extended in the axial direction from the end of the receiving coil.

Further, in the invention of the receiving detonator for a remote wireless blasting apparatus described in claim 2, a receiving coil having a hollow portion, a core arranged in the hollow portion, and a receiving circuit connected to the receiving coil. And an explosive that is initiated by energy from the receiving circuit, the explosive is arranged on an extension line in the axial direction of the receiving coil, the core is extended in the axial direction from the end of the receiving coil, and the extended core is provided. The explosive has a portion overlapping in the axial direction.

In addition, in the invention described in claim 3, in the invention described in claim 2, the core is formed by bending in the middle part, and the explosive can be arranged on the extension line of the hollow part of the receiving coil. It is a thing.

[0015]

According to the first aspect of the present invention, the core extended in the axial direction from the end of the receiving coil enables more magnetic field generated by the magnetic field generator to be collected, and the detonation ability for the explosive is enhanced. To be

Further, in the invention described in claim 2, since the core of the extension portion and the explosive have a portion overlapping in the axial direction, the length of the receiving detonator can be shortened accordingly.

According to the third aspect of the present invention, the core is bent and formed in the middle portion, and the explosive can be arranged on the extension line of the hollow portion of the receiving coil. Therefore, the explosive of a required size can be arranged at an effective position on the opposite side of the receiving coil, and the receiving detonator can effectively function.

[0018]

【Example】

(Embodiment 1) An embodiment of the present invention will be described below with reference to the drawings.

First, the magnetic field transmitting device in the remote radio blasting device will be described. As shown in FIG. 5, the magnetic field generator 11 includes a loop antenna 12 and an AC oscillator 13, and is movably arranged in a tunnel 14. The loop antenna 12 is mounted and fixed on a trolley 15, and is configured by being wound by a conductor 16 having a predetermined thickness so that the side surface has a circular shape, a rectangular shape, an elliptical shape, or the like. The loop antenna 12 has a diameter or a side length of 1 to 10 m, preferably 2 to 7 m, depending on the size of the blast target. In addition, the number of turns is to obtain an AC magnetic field of desired strength.
5 to 500 times.

Further, the loop antenna 12 is preferably arranged at a position far from the face 17 at the tip of the tunnel 14 in order to minimize the influence of flying stones due to blasting. If necessary, a protective plate (not shown) such as metal or wood, Kevlar, or a protective sheet using carbon fiber or glass fiber is provided on the front surface of the loop antenna 12 to protect the loop antenna 12 against flying stones at the time of blasting.

Moreover, the loop antenna 12 has a face 17
It is necessary to uniformly radiate the magnetic field necessary for detonating the plurality of receiving detonators 19 loaded in the blast holes 18 bored in the face 17 to the face 17, and the size is set so that it can be easily moved. Even if the loop antenna 12 has a length larger than its diameter, a magnetic field is supplied to the front surface of the face 17.

The AC oscillator 13 is placed at a position separated from the loop antenna 12 by a predetermined distance, and is connected to the conductor 16 of the loop antenna 12 by a connecting wire 20. This AC oscillator 13 functions with a vehicle battery or an underground power source, and its voltage is 24 to 400V. The loop antenna 12 generates an AC magnetic field by the AC current supplied from the AC oscillator 13. The frequency of this AC magnetic field is the same as the frequency of the AC current oscillated by the AC oscillator 13. Also,
The frequency of this alternating magnetic field is a few kHz or less, preferably 100 to 1000 Hz, because it must pass through rock mass. In this embodiment, an alternating current having a frequency of 550 Hz is supplied to the loop antenna 12.

Since the frequency of the AC magnetic field used in this embodiment is a frequency that is not used in communication or a general power source, there is no fear of affecting those devices. Also,
Since the receiving detonator 19 is tuned only to the frequency of the alternating magnetic field generated by the magnetic field generator 11, it does not malfunction due to radio waves of other different frequencies.

The loop antenna 12 oscillates an alternating magnetic field having the same frequency as the alternating current by the alternating current oscillated by the alternating current oscillator 13. The receiving coil 21 in the receiving detonator 19 in the blast hole 18 is tuned to this AC magnetic field.
Electromotive force is generated and the energy is stored in the receiving circuit unit 22. Then, the reception circuit unit 22 is generated by the ignition signal.
The ignition energy is released from the. This ignition energy ignites the electric detonator 23 of the receiving detonator 19 to explode the explosive 24.

Next, the receiving detonator 19 used in the remote wireless blasting apparatus of this embodiment will be described. As shown in FIG. 1, the receiving coil 21 is housed on one end side in a housing case 25, and the conductive wire 26 is wound many times from one end side to the other end side to have a predetermined length and diameter, and its center. Has a hollow portion 27 penetrating in the axial direction. The receiving coil 21 tunes to the alternating magnetic field and generates an electromotive force. The core 28 as shown in FIG. 7 has a so-called crank shape having a bent portion 29 bent at an intermediate portion. For example, as shown in FIG. 8, the core 28 has a plate thickness of 0.1 to 2
A plurality of crank-shaped thin plates 31 formed by continuous punching from a thin plate material 30 of about mm are laminated. A silicon steel plate or the like is used as the thin plate material 30.

The shape of the core 28 is the receiving coil 21.
What is the shape of the cross section of the portion of the core 28 arranged in the hollow portion 27, which is circular, oval, rectangular, polygonal, or the like that can be arranged in the hollow portion 27 and can be inserted into the blast hole 18? It may have any shape.

The length L of the core 28 is usually 10 to 1000 mm, preferably 30 to 500 mm. The diameter, side or width of the core 28 is usually 5 to 90% of the diameter of the blast hole 18, or 5
~ 45mm.

The preferred shape of the core 28 is the crank shape shown in FIG. 1. By making the crank shape, the core 28 can be arranged in the hollow portion 27 at the center of the receiving coil 21, and the core 28 has the same diameter as the receiving coil 21. And an explosive 24 capable of maintaining the detonation.

The material of the core 28 is iron-based metal magnetic material, soft magnetic alloy or oxide soft magnetic material (soft ferrite).
And other soft magnetic materials. As shown in FIG. 1, one end of the core 28 is inserted and arranged in the hollow portion 27 of the receiving coil 21, and the core 28 focuses the alternating magnetic field to increase the magnetic field density. Moreover, by extending the core 28 beyond the length of the receiving coil 21, the receiving ability can be further enhanced. In this case, the extension direction is preferably on the magnetic field generator 11 side.

The receiving circuit section 22 is connected to the receiving coil 21, converts the electromotive force into energy necessary for ignition of the explosive 24, stores the energy, and releases the ignition energy. The explosive charge 24 is accommodated on the other end side of the storage case 25 on the extension line of the receiving coil 21 in the central axis direction so as to be overlapped with the other end of the core 28 in the axial direction. The electric detonator 23 is loaded almost at the center of one end of the explosive charge 24 and inserted into one end face of the explosive charge 24. This electric detonator 23
Explodes the explosive 24 by the ignition energy of the receiving circuit section 22.

As shown in FIGS. 2 and 5, a plurality of blast holes 18 are formed in the innermost face 17 of the tunnel 14 at a predetermined depth. The innermost part of each blast hole 18 is shown in FIG.
A receiving detonator 19 as shown in Fig. 1 is arranged, and on the front surface thereof is a colloidal dynamite, a water-containing explosive, a plastic explosive (P
BX) or an explosive 24 such as an ammonium nitrate oil explosive. A filler 32 such as sand, clay, or synthetic resin is filled on the opening end side of the blast hole 18 to seal the blast hole 18. The ANFO explosive is loaded outside the receiving detonator 19. Generally, the larger the diameter of the explosive 24, the better the detonation propagating property and the destructive force increase. Therefore, it is preferable that the explosive 24 charged into the receiving detonator 19 and the blast hole 18 has a large diameter.

As shown in FIGS. 3 (a) and 3 (b), the storage case 25 has a cutout portion 33 formed by cutting out a part of the cylinder in the entire length direction by an elastic material. The receiving detonator 19 is loaded inside. When the receiving detonator 19 is loaded into the storage case 25, the receiving detonator 19 is removed from the notch 33 of the storage case 25 as shown in FIGS. 4A and 4B. Insert by spreading it open.

Next, the receiving circuit section 22 will be described with reference to FIG. A tuning capacitor 34 is connected in parallel to the receiving coil 21 and tunes to an alternating magnetic field generated from the magnetic field generator 11 to generate an electromotive force. The diode 35 and the diode 36 are connected to the receiving coil 21 in series, and further connected to the ignition capacitor 37. A time constant circuit composed of a capacitor 38 and a resistor 39 is provided in parallel with the receiving coil 21, and when an ignition signal indicating that the AC magnetic field has disappeared is input, the input side electrode voltage of the diode 36 is preset by this time constant circuit. Dropped in time. A PNP transistor 40 is provided between the time constant circuit and the diode 36.
Is connected, and the voltage drop due to this time constant circuit causes P
The NP-type transistor 40 starts conducting.

An NPN transistor 41 forming a positive feedback circuit is connected to the PNP transistor 40. That is, the base of the PNP transistor 40 is N
It is connected to the collector of the PN type transistor 41. The electric detonator 23 is connected between the emitter of the NPN-type transistor 41 and the ignition capacitor 37, and is detonated by energization. By adjusting the capacitor capacity and resistance value of the time constant circuit composed of the capacitor 38 and the resistor 39,
Since the energization time to the electric detonator 23 can be set arbitrarily and accurately, it is possible to perform step blasting in which blasting is performed in a predetermined order.

In the case of the circuit shown in FIG. 6, the ignition signal is generated when the alternating magnetic field disappears. As the ignition signal, it is possible to release energy by a circuit modified so as to operate with respect to an alternating magnetic field having a different frequency.

The induced electromotive force generated at both ends of the receiving coil 21 by the AC magnetic field is linked to the number of turns of the receiving coil 21, the angular velocity of the interlinking magnetic flux, and the inside of the receiving coil 21 as shown in the following equation (1). It is calculated as the product of the amount of magnetic flux.

E = nωΦ (V) (1) n: number of turns of the receiving coil (T), ω: angular velocity of the interlinkage magnetic flux (rad
/ sec), Φ: magnetic flux (Wb) interlinking in the receiving coil 3 When this equation (1) is further explained, the induced electromotive force is the oscillation frequency as shown in the following equation (2). And the relative magnetic permeability of the core 28 in the receiving coil 21, the number of turns of the receiving coil 21, the cross-sectional area of the receiving coil 21, and the magnetic field component orthogonal to the receiving coil 21.

Ω = 2πf f: Oscillation frequency (Hz) Φ = B · S = μ · H · S = μ ₀ · μ _r · Hz · S B: Linkage magnetic flux density (Wb / m ² ), S: Reception Coil cross section (m
² ), μ: Permeability (H / m) of the receiving coil, Hz: Magnetic field (AT / m) perpendicular to the coil, μ ₀ : Permeability in vacuum = 4π × 10-7
(H / m), μ _r : relative permeability of core, n: number of turns of receiving coil
(T) Therefore, e = 8π ² · 10 ^-7 · n · f · μ _r · S · Hz (V) (2) The diameter D of the receiving coil 21 is to be inserted into the blast hole 18
(Cross-sectional area S = πD ^2/4), it is necessary to under drilling diameter or less.
In tunnel excavation, the diameter of the blast hole 18 is usually φ38.
mm to φ50 mm, φ42 mm is commonly used.
Furthermore, in tunnel excavation, the detonator 19 was used to blast the hole 1.
Since it is placed in the innermost part of 8 for blasting, hole butt,
That is, there is a possibility that a part of the tip end of the blast hole 18 remains because there is a portion of the receiving detonator 19 where there is no explosive. In order to prevent this, it is necessary to make the length of the receiving coil 21 as short as possible.

The magnetic field Hz orthogonal to the receiving coil 21 is determined by the oscillation capability of the magnetic field generator and the position of the loop antenna 12, and the core 2 arranged at the center of the receiving coil 21.
The relative magnetic permeability μ _r of No. 8 is determined by the material used for the core 28.

As described above, each variable in the equation (2) has a constraint condition. Further, although not shown in the equation (2), the volume of the core 28, that is, the length, the diameter or the weight,
Receiving capacity changes. For example, assuming that the receiving detonator 19 using a ferrite core having the same length as the receiving coil 21 has a detonable distance of 15 m, if the material is changed to a silicon steel plate under the same conditions, the detonable distance becomes about 19 m. Further, the cross-sectional area is the same, and the length of the core 28 is equal to
If the core material is doubled and ferrite is used, the possible firing distance is about 21 m. Further, if the core 28 has the same cross-sectional area and the length of the core 28 is four times the length of the receiving coil 21 and the material is a silicon steel plate, the possible firing distance is about 26 m. In this way, the possible firing distance greatly changes depending on the volume and material of the core 28.

As a result of examining these conditions, the number of turns n of the receiving coil 21 is usually 100 to 100,000 (T), preferably 20.
00 ~ 50000 (T), the diameter of the receiving coil 21 is φ35mm ~
φ47 mm. Basically, this diameter is preferably set to (the diameter of the blast hole 18 minus several mm). In addition, the receiving coil 21
The length is usually 5 to 300 mm, preferably 20 to 200 mm. The wire material of the receiving coil 21 is selected from a conductive wire such as a copper wire, an aluminum wire, and an iron wire. If necessary, the receiving coil 21 may have a rectangular cross-sectional shape.

As shown in FIG. 9, the blast holes 18 of the first group
((1) in FIG. 9) is provided at the center position of the cutting face 17 and the left and right positions thereof. The blast hole 18 of the second group ((2) in FIG. 9) is provided in an annular shape around the blast hole 18 of the first group. The blast hole 18 of the third group ((3) in FIG. 9) is formed in an arc shape above the blast hole 18 of the second group, and the blast hole 18 of the fourth group ((4) in FIG. 9) is a facet. It is formed on the upper peripheral edge of 17. The blast hole 18 of the fifth group ((5) in FIG. 9) is formed in the lower peripheral edge of the face 17, and the blast hole 18 of the sixth group (FIG. 9) is formed.
The inside (6) is provided on both sides of the lower end of the face 17. The arrow near the center in FIG. 9 indicates the direction in which the blast hole 18 extends.

As shown in FIG. 10, the blast holes 18 of the first group.
Are formed into V-shapes with the distance between each other becoming narrower toward the inner part, and this part is blown up by core blasting to increase the free surface. The blast holes 18 of the second group are also formed such that the distance between them is slightly narrowed toward the back, and the blast holes 18 of the fourth and fifth groups are formed so as to be slightly expanded toward the back.

When the distance between the loop antenna 12 and the receiving detonator 19 is close to the face 17, the distance greatly changes depending on the magnitude of the vector component of the alternating magnetic field. Therefore, the loop antenna 12 is not suitable for the receiving detonator 19 that requires an alternating magnetic field in one direction. Further, if it is close to the face 17, there is a possibility that the loop antenna 12 may be damaged by flying stones caused by blasting. However, since the strength of the alternating magnetic field is attenuated in proportion to the cube of the distance, if the distance from the face 17 is too large, a large transmitting device is required.

For the above reasons, the distance between the loop antenna 12 and the receiving detonator 19 is preferably 5 to 200 m. Further, the central axis of the loop antenna 12 is arranged at a right angle to the cutting face 17 in order to cause a predetermined number of alternating magnetic fields to intersect with the receiving detonator 19.

In the first embodiment, the number of turns of the receiving coil 21 of the receiving detonator 19 is 30000 (T), the diameter is 40 mm, and the coil length is
It is 50 mm. The core 2 has a circular cross section with a diameter of 10 mm and a length L.
Is 200mm and is made by molding ferrite into a crank shape.

As shown in FIGS. 9 and 10, the face 17 in the headrace tunnel has a width of 2 m and a height of 2.5 m, a traveling length D, that is, a depth capable of being excavated by one blasting is 1.0 m, and the number of holes to be drilled. It was 51. The loop antenna 12 used was a coil having a diameter of 1.8 m and wound 60 times, and was installed 15 m away from the receiving detonator 19. An AC current of 550 Hz was supplied to the loop antenna 12 by the AC oscillator 13, the receiving detonators 19 were detonated in the order of the numbers shown in FIG. 9, and the rock mass in the tunnel, which was the object of blasting, was blasted. As a result, all blast holes 18
It was possible to reliably detonate the receiving detonator 19 inside.

As described above, in the remote radio blasting apparatus of the first embodiment, the loop antenna 12 for generating a magnetic field, which is installed at a sufficient distance from the face 17, and the receiving detonator 19 arranged in the blast hole 18 are evenly arranged. At the same time, a stable magnetic field can be supplied, and at the same time, the receiving capability of the receiving and detonating device 19 can be enhanced, and the explosive 24 can be surely detonated.

For this reason, since the power supply can be eliminated in the reception detonator 19, the structure of the reception detonator 19 can be simplified, and the size and weight can be reduced. Therefore, the manufacturing of the receiving detonator 19 can be facilitated, and the workability of installing the receiving detonator 19 can be improved. Further, it is not necessary to increase the diameter of the blast hole 18 or increase the length of the hole, which also improves workability.

In addition, since the receiving detonator 19 does not require an internal power source such as a battery and the detonating energy is transmitted from the receiving circuit section 22 to the explosive 24 immediately before the blasting, the possibility that the explosive 24 may be erroneously exploded can be avoided. it can. Moreover, blast hole 1
It becomes possible to mechanize the loading of the receiving detonator 19 and the explosive 24 into the inside 8, and the efficiency of the loading work can be achieved, and the work performed by the worker with the cutting face 17 can be reduced, and the workability is improved. Therefore, it is possible to improve efficiency such as labor saving and labor saving of excavation work by the blasting method.

In addition, by providing a protective sheet in front of the loop antenna 12 if necessary, the loop antenna 12 can be reliably protected against accidental flying stones. Since the loop antenna 12 can be moved by a trolley 13 having moving means such as wheels and tracks, the loop antenna 12 can be moved forward and backward, and it is easy to move to another tunnel 14 and repeatedly. Since it can be used, workability is improved.

Therefore, the remote wireless blasting apparatus of this embodiment can be effectively used for tunnel construction and excavation construction of underground space, etc., which have been conventionally impossible. (Embodiment 2) Next, Embodiment 2 embodying the present invention will be described. In this embodiment, only the points different from the first embodiment will be described.

In the second embodiment, the number of turns of the receiving coil 21 of the receiving detonator 19 is 20000 (T), and the core 28 is made of a silicon steel sheet having a square cross section with a side of 15 mm and a length L of 150 mm.
A stack of sheets was used.

As shown in FIG. 11, the cutting face 17 has a semicircular shape with a radius of 6 m, a traveling length of D4.5 m, 100 holes, and core cutting is performed by excavating a burnt road tunnel in its entire cross section. . As shown in FIG. 12, two parallel holes 42 are formed.
Is provided almost at the center of the face 17, and is for increasing the free surface. All the blast holes 18 in which the receiving detonator 19 is loaded extend in parallel with each other.

The loop antenna 12 has a width of 4 m and a length of 2 m.
× Receiving detonator 1 with a depth of 1 m and 80 turns
It was installed at a distance of 30m from 9. Then, an alternating current of 550 Hz was supplied to the loop antenna 12 by the alternating current oscillator 13, and the receiving detonator 19 was detonated in the order of the numbers shown in FIG. 9 to explode the bedrock in the tunnel 14 which is the object of blasting.

As a result, the receiving detonators 19 in all the blast holes 18 could be reliably detonated even though the face 17 of the road tunnel had a large cross section. The present invention may be embodied by changing the configuration as follows, for example. (A) As shown in FIG. 13 (a) or (b), the core 28
To have a cylindrical shape, and bend it in the middle to form a crank shape. As shown in FIGS. 13C to 13F, the core 28
Is formed in a cylindrical shape, and is disposed so as to extend from the length of the receiving coil 21 to the magnetic field generator 11 side or the opposite side. In these cases, explosive charge 24 is placed around the perimeter of the extension of core 28. (B) As shown in FIG. 14 (a) or (b), the core 28
Is formed in the hollow portion 27 of the receiving coil 21, and is formed in a cylindrical shape or a hexagonal tube shape in the extended portion of the receiving coil 21. As shown in FIG. 14 (c), the extension portion of the core 28 should be formed in a rectangular tube shape with four plate-like bodies. FIG. 14 (d)
Forming an extension of the core 28 into a coil, as shown in FIG. As shown in FIG. 14 (e), the extension parts of the core 28 should be arranged vertically opposite to each other with two thin cylinders. (C) Use of the detonator for remote wireless blasting according to the present invention for mining underground or above ground such as mines, quarries, leveling and construction. (D) Use the step detonator as the means of step explosive blasting, not by the time constant circuit in the receiving detonator. Also, combine the time constant circuit and the step detonator to create more delay time. (E) In order to improve the loadability of the receiving detonator 19 into the blasting hole 18, the hole side of the receiving detonator 19 should be tapered so as to reduce its diameter, or a conical cup should be attached. (F) The explosive 24 is arranged from the innermost portion of the blast hole 18, and the electric detonator 23 extended from the receiving detonator 19 is blasted into the blast hole 18.
It is loaded in the explosive 24 in the innermost part of the
Place it on the explosive 24 on the side of the face 17 and connect it with a leg or the like. (G) To make the length of the portion of the core 28 extending from the receiving coil 21 shorter or longer than the length of the explosive 24.

Further, the technical idea understood from the above embodiment will be described below. (1) The remote wireless blasting device according to claim 1, wherein the core is made of a silicon iron alloy. According to this structure, properties such as magnetic permeability, iron loss, workability, and strength can be satisfactorily exhibited, and it is easily available. (2) The remote wireless blasting device according to claim 1, wherein the core is formed by laminating a plurality of thin plate materials. With this configuration, the core can be easily manufactured by press molding. (3) The remote wireless blasting device according to claim 1, wherein the receiving detonator is housed in a housing case. With this configuration,
The receiving detonator can be easily inserted and arranged in the blast hole. (4) The remote wireless blasting device according to (3), wherein the storage case is formed of an elastic material into a tubular shape, and at least a part of which is cut out along the length direction thereof. With this configuration, the receiving detonator can be easily housed in the housing case. (5) The remote wireless blasting apparatus according to claim 1, wherein the antenna is a loop antenna in which a conducting wire is wound in a coil shape, and the central axis line is arranged substantially orthogonal to the face in the tunnel. According to this structure, the magnetic field can be reliably intersected with the receiving detonator to the extent required. (6) The remote wireless blasting device according to claim 1, wherein the core is extended from the end of the receiving coil toward the oscillator side in the axial direction. With this configuration, it is possible to enhance the reception capability of the reception detonator.

[0058]

As described in detail above, according to the remote radio-blasting device of the first aspect, it is possible to improve the receiving capability of the receiving and detonating device, and to generate a magnetic field installed sufficiently away from the face. The receiving detonator arranged in the blast hole can be securely detonated from the antenna for use.

Further, it is possible to simplify the structure by eliminating the power supply in the receiving detonator, and to reduce the size and weight. In addition, a power source such as a battery is not required in the receiving and detonating unit, and the detonating energy can be transmitted to the explosive immediately before blasting, eliminating the risk of accidental explosion and reducing the work done by the worker by the face. Can be improved.

[Brief description of drawings]

FIG. 1 is a perspective view of a receiving detonator embodying the present invention.

FIG. 2 is a perspective view showing a state where the receiving detonator is arranged in a tunnel.

FIG. 3 (a) is a side view of the receiving detonator housed in a housing case, and FIG. 3 (b) is a front view of the same.

FIG. 4A is a side view of the receiving detonator housed in a storage case, and FIG. 4B is a front view of the same.

FIG. 5 is a perspective view showing a state where a remote wireless blasting device is arranged in the tunnel.

FIG. 6 is a circuit diagram showing a receiving circuit unit.

FIG. 7 is a perspective view showing a laminated core.

FIG. 8 is a plan view showing a state in which a crank-shaped material is cut out from a steel plate.

FIG. 9 is a front view showing the arrangement of blast holes formed in the face of Example 1.

FIG. 10 is a sectional view showing a blast hole in the same manner.

FIG. 11 is a front view showing the arrangement of blast holes formed in the face of Example 2.

FIG. 12 is an enlarged front view showing an arrangement of blast holes and holes.

13A to 13F are perspective views showing a core shape and a receiving coil as another example.

14A to 14D are perspective views showing a core shape and a receiving coil as another example.

[Explanation of symbols]

11 ... Magnetic field generator, 12 ... Loop antenna, 13 ... AC oscillator, 19 ... Receiving detonator, 21 ... Receiving coil, 2
2 ... Receiving circuit part, 5 ... Detonator, 24 ... Explosive as energy generating part, 27 ... Hollow part, 28 ... Core.

Claims (3)

[Claims] 1. A magnetic field generator and a receiving detonator, wherein the magnetic field generator includes an AC oscillator that generates an alternating current of a specific frequency and an antenna that generates a magnetic field by the alternating current. The device includes a receiving coil having a hollow portion, a core arranged in the hollow portion, a receiving circuit connected to the receiving coil, and an explosive charge that is detonated by energy from the receiving circuit. A remote wireless blasting device that is arranged on an extension line in the axial direction and has a core extended in the axial direction from the end of the receiving coil. 2. A receiving coil having a hollow portion, a core arranged in the hollow portion, a receiving circuit connected to the receiving coil, and an explosive charge that is detonated by energy from the receiving circuit, and receives the explosive charge. Reception initiation for a remote radio blasting device, which is arranged on an extension of the coil in the axial direction, extends the core axially from the end of the receiving coil, and has a portion where the extended core and explosive overlap in the axial direction. apparatus. 3. The receiving and detonating device for remote radio blasting according to claim 2, wherein the core is formed in a bent shape at an intermediate portion so that the explosive can be arranged on an extension line of the hollow portion of the receiving coil.