Relay device for wireless detonation system, antenna for relay device and detonation method

Abstract

To provide a relay device for relay between an oscillator and a detonator with an antenna enhanced in transmission / reception efficiency of radio signals.SOLUTION: A relay device 20 for a wireless detonation system 1 which relays signals between an oscillator and a detonator 10 has an uplink-side antenna 28 which transmits / receives signals to and from the oscillator. The relay device 20 has a downlink-side antenna 30 which transmits / receives signals by radio to / from the detonator 10. The downlink antenna 30 has a first coil 31 electrically connected to a downlink-side receiving circuit 25 and a downlink-side transmitting circuit 26 and also wound by the first number of turns. The downlink-side antenna 30 has a second coil 32 provided adjacently to and substantially coaxially with the first coil 31 and wound by the second number of turns larger than the first number of turns. The downlink-side antenna 30 has a capacitor 33 for resonance electrically connected to the second coil 32.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a wireless detonation system relay device provided in a wireless detonation system used, for example, at excavation sites such as tunnels, rock crushing sites, and building structure crushing sites, a relay device antenna provided in the relay device, and a detonation method using the wireless detonation system relay device or the relay device antenna. [Background technology]

[0002] Detonators are used in blasting operations, for example, at tunnel excavation sites. Multiple charge holes are formed in the face of the tunnel to be blasted. The charge holes are, for example, roughly circular openings with a diameter of a few centimeters and a depth of several meters. A detonator is inserted into the back of the charge hole, and an explosive is inserted in front of the detonator. A blasting device is installed in a remote location away from the face. The blasting device sends an initiation signal to the detonator in the charge hole. This ignites the electric detonator of the detonator, detonating the explosive.

[0003] As described in Patent Document 1, a conventional wireless detonation system has a large loop-shaped antenna. The antenna is installed near the face and shaped to follow the outer periphery of the face. A large amount of power is sent to the antenna via a wire from a large power source installed in a remote location away from the face. The antenna wirelessly charges the detonators inside the face from the outside of the face. The antenna receives response signals and the like wirelessly transmitted from the detonators inside the face to the outside of the face. The antenna wirelessly transmits detonation signals and the like from the outside of the face to the detonators inside the face.

[0004] Conventionally used large antennas must be installed as close to the detonator as possible along the outer periphery of the tunnel face to improve charging efficiency. This increases the time required for tunnel face work, including installation. It also increases the risk of disasters such as falling rocks during installation. A larger antenna and longer wires result in higher impedance. Increasing the number of turns further increases impedance, making it difficult to improve antenna performance. Because the antenna shape changes to match the shape of the tunnel face, a large matching box must be prepared for impedance adjustment. Furthermore, a large high-frequency power source that generates a large amount of power must also be prepared. Several hundred meters of wire must be run from the antenna to the matching box and high-frequency power source. This increases the effort required to install the large matching box, high-frequency power source, and wiring, as well as the work time required for impedance adjustment.

[0005] Patent Document 2 describes a wireless detonation system equipped with a relay device that transmits and receives wireless signals between a blasting device and a detonator cap. The relay device is small enough to be inserted into an insertion hole formed in the face of a tunnel. The relay device has an upstream antenna that transmits and receives wireless signals to and from the blasting device outside the insertion hole. The relay device has a downstream antenna that transmits and receives wireless signals to and from the detonator cap inside the insertion hole. The downstream antenna is located deep inside the insertion hole. The detonator cap and the downstream antenna transmit and receive wireless signals to and from each other at frequencies that have high rock penetration, for example, 1 kHz to 500 kHz. The use of a small relay device can shorten work time, etc. However, a downstream antenna that is small enough to be inserted into the insertion hole has insufficient transmission and reception performance. Therefore, there is room for improvement in order to increase the transmission and reception efficiency of the downstream antenna. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 2018-087673 [Patent Document 2] International Publication No. 2022 / 014530 Summary of the Invention [Problem to be solved by the invention]

[0007] Therefore, it is necessary to provide a relay device that relays between the blasting device and the detonator with an antenna that improves the efficiency of transmitting and receiving radio signals. [Means for solving the problem]

[0008] One feature of the present disclosure relates to a relay device for a wireless detonation system that relays signals between a blasting device and a detonator. The relay device for a wireless detonation system has an upstream antenna that wirelessly transmits and receives signals to and from the blasting device. The relay device for a wireless detonation system has a downstream antenna that wirelessly transmits and receives signals to and from the detonator. The downstream antenna has a first coil that is electrically connected to a receiving circuit and a transmitting circuit and is wound with a first number of turns. The downstream antenna has a second coil that is disposed adjacent to the first coil and approximately coaxial with the first coil and is wound with a second number of turns that is greater than the first number of turns. The downstream antenna has a resonance capacitor electrically connected to the second coil.

[0009] Therefore, the second coil, electrically connected to the resonant capacitor, resonates at a predetermined frequency. This allows the second coil to efficiently transmit and receive signals at the resonant frequency wirelessly. Furthermore, the impedance can be suppressed by reducing the number of turns in the first coil. The second coil's impedance is reduced by resonating with the resonant capacitor, allowing for a larger number of turns. When the second coil receives a wireless signal, a current flows in the second coil, generating a magnetic field. This causes a current to flow in the first coil, transmitting the signal to the first coil. When the first coil transmits a signal, a current flows in the first coil, generating a magnetic field. This causes a current to flow in the second coil, causing the second coil to transmit a wireless signal. This increases the efficiency of wireless signal transmission and reception between the downstream antenna of the repeater device and the detonator.

[0010] According to another feature of the present disclosure, the first coil and the second coil are annular with a diameter of 300 mm to 1500 mm. The first number of turns is 1 to 6. The second number of turns is 3 to 30. Therefore, the downstream antenna can be provided with a size that is efficient for transmission and reception, easy to carry, and allows for a reduction in installation time. Moreover, the first coil can be provided with a number of turns that can effectively suppress impedance. The second coil can be provided with a number of turns that allows for efficient transmission and reception of wireless signals.

[0011] According to another feature of the present disclosure, the downstream antenna transmits and receives signals to and from detonators in a charge hole provided on the working face using signals of 1 kHz to 500 kHz, and therefore the downstream antenna can transmit and receive signals to and from the detonators in the charge hole at frequencies that have high rock penetration.

[0012] According to another feature of the present disclosure, a relay device for a wireless detonation system has a main body that houses a receiving circuit, a transmitting circuit, and a resonant capacitor. The main body is inserted into an insertion hole provided in a working face. The first coil and the second coil are held in the main body so that they are positioned outside the insertion hole. Therefore, by inserting the main body into the insertion hole, the first coil and the second coil, which are larger in diameter than the insertion hole, can be held near the working face. As a result, a downstream antenna with high transmission and reception efficiency can be positioned in a stable position near the working face. This allows for good transmission and reception of signals with the detonator.

[0013] According to another feature of the present disclosure, the relay device for a wireless detonation system includes an annular frame member that holds the first coil and the second coil and is made of an insulating material, and thus the shape of the first coil and the second coil is maintained by the frame member, thereby suppressing changes in impedance between the circuits on the first coil side and the second coil side.

[0014] According to another feature of the present disclosure, the first coil and the second coil are coaxial, and the axial direction of the coaxial coil is approximately perpendicular to the face of the winding. Therefore, by making the first coil and the second coil coaxial, the magnetic flux generated by each coil can be efficiently received. This improves the efficiency of signal transmission and reception between the first coil and the second coil. Furthermore, by making the axial direction approximately perpendicular to the face of the winding, the first coil and the second coil can be held in a stable position along the face of the winding.

[0015] Another feature of the present disclosure relates to a relay antenna used in a wireless detonation system for wirelessly transmitting and receiving signals to and from a detonator. The relay antenna has a first coil, a second coil, and a resonance capacitor. Therefore, by providing a first coil with reduced impedance and a second coil electrically connected to the resonance capacitor, a relay antenna with high transmission and reception efficiency can be provided.

[0016] Another feature of the present disclosure relates to a wireless detonation method using a relay device for a wireless detonation system or a relay device antenna. Therefore, by using a downstream antenna or a relay device antenna with high transmission and reception efficiency, signals can be transmitted and received efficiently between the detonator and the relay device. Furthermore, the downstream antenna can transmit and receive signals with the detonator loaded in the charge hole on the face while protruding outside the face. Therefore, while improving the work efficiency of installing the relay device, signals can be transmitted and received well between the relay device and the detonator. [Brief explanation of the drawings]

[0017] [Figure 1] 1 is a schematic diagram of the overall configuration of the wireless detonation system of the present disclosure and a tunnel excavation site. [Figure 2] FIG. 1 is a schematic diagram of a relay device, detonator and blaster inserted into a hole in the face. [Figure 3] FIG. 2 is a schematic diagram of a repeater antenna. [Figure 4] FIG. 2 is an exploded perspective view of a relay device antenna. [Figure 5] FIG. 1 is a block diagram of a relay device and a detonator. [Figure 6] 10 is a flowchart showing a process of receiving a radio signal by the relay device antenna. [Figure 7] 10 is a flowchart showing a process of transmitting a radio signal from a relay device antenna. DETAILED DESCRIPTION OF THE INVENTION

[0018] One embodiment of the present disclosure will be described with reference to Figures 1 to 7. The same reference numerals in the description refer to the same elements having the same function, although the same description will not be repeated. A wireless detonation system 1 is used to detonate an explosive 2 to excavate or crush structures such as tunnels, the seabed, rocks, and buildings. In this embodiment, an excavation site of a tunnel 40 will be described as an example, as shown in Figure 1. The tunnel 40 has a vertically extending face 41 at its rear. A plurality of charge holes 41a are provided in the face 41 at predetermined intervals in the vertical and horizontal directions. The charge holes 41a extend linearly perpendicular to the face 41. The charge holes 41a are, for example, circular, with a diameter of 30 to 100 mm, and are drilled to a depth of several meters.

[0019] As shown in Figures 1 and 2, each charging hole 41a is loaded with a cylindrical detonator 10 and multiple cylindrical explosives 2. The detonator 10 is loaded at the back of the charging hole 41a with the electric detonator 13 facing forward. The multiple explosives 2 are loaded forward of the detonator 10. The innermost explosive 2 adjacent to the detonator 10 is the parent die 2a into which the electric detonator 13 is inserted. The parent die 2a is ignited by the electric detonator 13 to detonate. Multiple booster dies 2b are arranged along the charging hole 41a forward of the parent die 2a. The multiple booster dies 2b detonate in a chain reaction when the parent die 2a is detonated. The entrance of the charging hole 41a forward of the explosives 2 is sealed with a sealing member 41c such as clay.

[0020] As shown in Figures 1 and 2, an insertion hole 41b is provided in the center of the working face 41, into which the main body 21 of the relay device 20 (described later) is inserted. The relay device 20 can be installed by inserting the main body 21 into the insertion hole 41b. Therefore, there is no need to prepare a separate stand or the like for installing the relay device 20. The insertion hole 41b extends linearly along the direction perpendicular to the working face 41. The insertion hole 41b is, for example, a circular hole with a diameter of 30 mm to 100 mm, and is drilled to a depth of 100 mm to 500 mm. It is desirable to provide the insertion hole 41b in a position close to the ground in the center of the working face 41, where the distances to the charging holes 41a located at the left end, right end, and top end are approximately the same.

[0021] As shown in Figures 1 and 2, the wireless detonation system 1 has a blasting machine 3 that transmits detonation signals and the like and receives response signals and the like. The blasting machine 3 is used at a position sufficiently distant, for example, about 100 to 1000 m from the working face 41. The blasting machine 3 has an antenna 3a that transmits and receives radio signals, for example, in the UHF band (300 MHz to 3 GHz). The blasting machine 3 has an input unit 3b that can be operated to send radio signals. The blasting machine 3 has an output unit 3c that can display information received by the antenna 3a.

[0022] As shown in Figures 2 and 5, the detonator 10 has a cylindrical main body tube 11. The main body tube 11 is provided with a diameter smaller than the diameter of the charge hole 41a. The main body tube 11 houses an electronic circuit 12, an electric detonator 13, and an antenna 14. The electronic circuit 12 is provided with a capacitor 12a that stores power for driving and detonation. The electric detonator 13 is electrically connected to the electronic circuit 12. When the electronic circuit 12 receives a detonation signal via the antenna 14, power is supplied from the capacitor 12a to the electric detonator 13. This causes the electric detonator 13 to ignite and detonate the explosive 2.

[0023] As shown in Figures 2 and 5, the antenna 14 also serves as a receiving coil that receives electrical energy wirelessly. The antenna 14 is wound in an annular shape to form a coil. The axial direction of the antenna 14 is the direction in which the main body tube 11 extends, and is substantially perpendicular to the working face 41. The antenna 14 transmits and receives wireless signals at frequencies that have good penetration through rock, for example, between 1 kHz and 500 kHz. The antenna 14 receives electrical energy at frequencies between 1 kHz and 500 kHz from a separately prepared power supply device.

[0024] As shown in FIGS. 1 and 2, the wireless detonation system 1 includes a relay device (relay device for wireless detonation system) 20 that relays signals between the blasting device 3 and the detonator cap 10. The relay device 20 includes a cylindrical main body 21 and an upstream antenna 28 and a downstream antenna (relay device antenna) 30 that are electrically connected to an electronic circuit on a circuit board 22 within the main body 21. The main body 21 has a diameter smaller than the diameter of the insertion hole 41b formed in the working face 41. The main body 21 is inserted into the insertion hole 41b and installed. The upstream antenna 28 and the downstream antenna 30 are exposed outside the insertion hole 41b. The upstream antenna 28 transmits and receives wireless signals to and from the antenna 3a of the blasting device 3 at a frequency of, for example, 300 MHz to 3 GHz. The downstream antenna 30 transmits and receives wireless signals to and from the antenna 14 of the detonator cap 10 at a frequency of, for example, 1 kHz to 500 kHz, more preferably 30 kHz to 300 kHz.

[0025] 3 and 5, relay device 20 has a circuit board 22 and a power supply 27 housed in main body 21. Circuit board 22 is provided with a CPU serving as control circuit 22a that controls the operation of each component of relay device 20. Circuit board 22 is provided with an upstream receiving circuit 23, an upstream transmitting circuit 24, a downstream receiving circuit 25, and a downstream transmitting circuit 26. Power supply 27 supplies power to each component of relay device 20 via control circuit 22a.

[0026] As shown in Fig. 5, the upstream receiving circuit 23 detects an analog signal received by the upstream antenna 28 and outputs the signal as a digital signal to the control circuit 22a. The upstream transmitting circuit 24 modulates the digital signal output from the control circuit 22a into an analog signal and outputs the analog signal to the upstream antenna 28. The upstream antenna 28 transmits a wireless signal when a current flows due to the signal sent from the upstream transmitting circuit 24. The downstream receiving circuit 25 detects an analog signal received by the first coil 31 of the downstream antenna 30 and outputs the digital signal to the control circuit 22a. The downstream transmitting circuit 26 modulates the digital signal output from the control circuit 22a into an analog signal and outputs the analog signal to the first coil 31 of the downstream antenna 30.

[0027] As shown in FIGS. 3 to 5 , the downstream antenna 30 includes a first coil 31 and a second coil 32. The first coil 31 and the second coil 32 are annularly shaped, with diameters D1 and D2 of 300 mm to 1500 mm, respectively. The diameter D1 of the first coil 31 and the diameter D2 of the second coil 32 are substantially the same. The first number of turns of the first coil 31 is, for example, 1 to 6 to suppress impedance. The second number of turns of the second coil 32 is greater than the first number of turns and is, for example, 3 to 30. The first axis J1 at the center of the first coil 31 and the second axis J2 at the center of the second coil 32 are substantially coaxial, more preferably, aligned coaxially, with the axial direction substantially perpendicular to the face 41. In the present disclosure, substantially coaxial refers to, for example, a relationship in which the first axis J1 or its extension is located within the diameter D2 of the second coil 32, and the second axis J2 or its extension is located within the diameter D1 of the first coil 31.

[0028] As shown in Figure 2, the axial direction of the first coil 31 and the second coil 32 is not parallel to the direction in which the downstream antenna 30 of the relay device 20 and the antenna 14 of each detonator 10 transmit and receive signals, but is at least inclined. The axial direction of each detonator 10 is also not parallel to the direction in which the downstream antenna 30 and the antenna 14 of each detonator 10 transmit and receive signals, but is at least inclined. Therefore, the downstream antenna 30 and the antenna 14 of each detonator 10 can efficiently receive changes in the electric field and magnetic field from each other. Therefore, they can efficiently transmit and receive electromagnetic waves from each other.

[0029] As shown in FIGS. 3 and 4 , the downstream antenna 30 has an annular frame member 34 having approximately the same diameter as the first coil 31 and the second coil 32. The first coil 31 and the second coil 32 are held in the frame member 34 so that they are arranged coaxially and close to each other. Furthermore, the first coil 31 and the second coil 32 are held in the annular frame member 34, thereby maintaining their annular shape. This prevents impedance changes in the circuits on the first coil 31 side and the second coil 32 side. The frame member 34 is formed from an insulating material such as a synthetic resin or a wooden frame. The wooden frame may be, for example, a frame with a square coil wound around the outer periphery of two cross-shaped rods, or a frame with a hexagonal coil wound around the outer periphery of three crossed rods.

[0030] Instead of the frame member 34, the first coil 31 may be made of a material that is relatively strong and easily maintains its shape. For example, the first coil 31 may be made of a conductive material such as aluminum or copper that has a certain mechanical strength and is strip-shaped and several millimeters thick, several centimeters wide, and several meters long. The first coil 31 is formed by winding a strip-shaped member into a ring or polygonal shape. The second coil 32, wound around the inner or outer circumference of the first coil 31, is fixed. Since the shape of the first coil 31 is maintained by its strength, the shape of the second coil 32 fixed to the first coil 31 is also maintained. This makes it possible to prevent changes in impedance between the circuits on the first coil 31 side and the second coil 32 side.

[0031] As shown in FIGS. 3 to 5, the downstream antenna 30 has a resonance capacitor 33. The first coil 31 is electrically connected to the control circuit 22a via the downstream receiving circuit 25 and the downstream transmitting circuit 26. The first coil 31 and the second coil 32 are not electrically connected to each other. The resonance capacitor 33 is attached to the circuit board 22 without being electrically connected to the control circuit 22a. The second coil 32 is electrically connected to the resonance capacitor 33. The resonance capacitor 33 includes a fixed capacitor 33a and a variable capacitor 33b, such as a trimmer capacitor. The fixed capacitor 33a allows the inductance of the second coil 32 to be roughly set. The variable capacitor 33b allows the inductance of the second coil 32 to be adjusted. This allows the frequency at which the second coil 32 transmits and receives to be suitably adjusted.

[0032] 1 to 6, a series of operations in which the relay device 20 receives a radio signal from the detonator 10 and transmits the radio signal to the blasting device 3 will be described. First, the second coil 32 of the downstream antenna 30 receives a radio signal from the antenna 14 of the detonator 10 (step 01 in FIG. 6, hereinafter referred to as S01). The radio signal is, for example, a signal notifying that each detonator 10 has completed preparation for detonation. The second coil 32 resonates at a predetermined frequency using the resonance capacitor 33 (S02). The predetermined frequency is any value in the range of 1 kHz to 500 kHz. The second coil 32 generates a magnetic field in response to the signal of the resonated frequency (S03).

[0033] In the first coil 31 of the downstream antenna 30, a current is generated by the magnetic field from the second coil 32 (S04). The downstream receiving circuit 25 detects a signal from the current generated in the first coil 31 (S05). The control circuit 22a receives the detected signal and transmits it to the upstream transmitting circuit 24 (S06). The upstream transmitting circuit 24 modulates the signal and transmits it to the upstream antenna 28 (S07). The upstream antenna 28 transmits a wireless signal at a frequency of, for example, 300 MHz to 3 GHz toward the blasting device 3 (S08).

[0034] 1 to 5 and 7, a series of operations in which the relay device 20 receives a radio signal from the blasting device 3 and transmits the radio signal to the detonating caps 10 will be described. First, the upstream antenna 28 receives a radio signal from the antenna 3a of the blasting device 3 (S11). The radio signal is, for example, a detonation signal that detonates each detonating cap 10. The upstream receiving circuit 23 detects a signal from the radio signal received by the upstream antenna 28 (S12). The control circuit 22a receives the detected signal and transmits it to the downstream transmitting circuit 26 (S13). The downstream transmitting circuit 26 modulates the signal and transmits it to the first coil 31 of the downstream antenna 30 (S14).

[0035] The first coil 31 of the downstream antenna 30 generates a magnetic field in response to the signal (S15). The magnetic field from the first coil 31 causes a current to flow in the second coil 32 of the downstream antenna 30 (S16). The second coil 32 resonates at a predetermined frequency in the range of 1 kHz to 500 kHz using the resonance capacitor 33 (S17). The second coil 32 transmits a radio signal of the resonating frequency to the antenna 14 of the detonator 10 (S18).

[0036] As described above, the relay device 20 for the wireless detonation system 1, which relays signals between the blasting device 3 and the detonator 10, has an upstream antenna 28 that wirelessly transmits and receives signals to and from the blasting device 3, as shown in Figures 2 and 5. The relay device 20 has a downstream antenna 30 that wirelessly transmits and receives signals to and from the detonator 10. The downstream antenna 30 has a first coil 31 that is electrically connected to the downstream receiving circuit 25 and the downstream transmitting circuit 26 and is wound with a first number of turns. The downstream antenna 30 has a second coil 32 that is disposed adjacent to the first coil 31 and is wound with a second number of turns that is greater than the first number of turns. The downstream antenna 30 has a resonance capacitor 33 that is electrically connected to the second coil 32.

[0037] Therefore, the second coil 32 electrically connected to the resonance capacitor 33 resonates at a predetermined frequency. Therefore, the second coil 32 can efficiently transmit and receive signals at the resonating frequency wirelessly. Furthermore, the impedance can be suppressed by reducing the number of turns of the first coil 31. The second coil 32 can have a larger number of turns because its impedance is reduced by resonating with the resonance capacitor 33. When the second coil 32 receives a wireless signal, a current flows in the second coil 32, generating a magnetic field. This causes a current to flow in the first coil 31, transmitting the signal to the first coil 31. When the first coil 31 transmits a signal, a current flows in the first coil 31, generating a magnetic field. This causes a current to flow in the second coil 32, causing the second coil 32 to transmit a wireless signal. This improves the efficiency of wireless signal transmission and reception between the downstream antenna 30 of the relay device 20 and the detonator 10.

[0038] As shown in Figures 3 and 4, the first coil 31 and the second coil 32 are annular and have a diameter of 300 mm to 1500 mm. The first number of turns is 1 to 6. The second number of turns is 3 to 30. The ratio of the first number of turns to the second number of turns is preferably 1:5 to 1:50, and more preferably 1:7 to 1:30. Therefore, the downstream antenna 30 can be provided with a size that allows efficient transmission and reception, is easy to carry, and shortens the installation work time. Moreover, the first coil 31 can be provided with a number of turns that can effectively suppress impedance. The second coil 32 can be provided with a number of turns that allows efficient transmission and reception of wireless signals.

[0039] 2 and 5, the downstream antenna 30 uses signals of 1 kHz to 500 kHz to transmit and receive signals to and from the detonator 10 in the charge hole 41a provided in the working face 41. Therefore, the downstream antenna 30 can transmit and receive signals to and from the detonator 10 in the charge hole 41a at frequencies that have high rock penetration.

[0040] 2 and 5, the relay device 20 has a main body 21 that houses a downstream receiving circuit 25, a downstream transmitting circuit 26, and a resonance capacitor 33. The main body 21 is inserted into an insertion hole 41b provided in the working face 41. The first coil 31 and the second coil 32 are held in the main body 21 so that they are positioned outside the insertion hole 41b. Therefore, by inserting the main body 21 into the insertion hole 41b, the first coil 31 and the second coil 32, which are larger in diameter than the insertion hole 41b, can be held near the working face 41. This allows the downstream antenna 30, which has high transmission and reception efficiency, to be positioned in a stable position near the working face 41. This allows for good signal transmission and reception with the detonator 10.

[0041] 3 and 4, the relay device 20 has an annular frame member 34 made of an insulating material and holds the first coil 31 and the second coil 32. Therefore, by maintaining the shapes of the first coil 31 and the second coil 32 with the frame member 34, it is possible to prevent the impedance from changing in the circuits on the first coil 31 side and the second coil 32 side.

[0042] As shown in Figure 4, the first coil 31 and the second coil 32 are coaxial, with the axial direction of the coaxial coil being approximately perpendicular to the working face 41 (see Figure 2). Therefore, by making the first coil 31 and the second coil 32 coaxial, the magnetic flux generated by each other can be efficiently received. This increases the efficiency of signal transmission and reception between the first coil 31 and the second coil 32. Furthermore, by making the axial direction approximately perpendicular to the working face 41, the first coil 31 and the second coil 32 can be held in a stable position along the working face 41.

[0043] 2 and 5, the relay device antenna 30 used in the relay device 20 for the wireless detonation system 1 to wirelessly transmit and receive signals with the detonator 10 has a first coil 31, a second coil 32, and a resonance capacitor 33. Therefore, by providing the first coil 31 with reduced impedance and the second coil 32 electrically connected to the resonance capacitor 33, it is possible to provide a relay device antenna 30 with high transmission and reception efficiency.

[0044] 2 and 5, this relates to a wireless detonation method using a relay device 20 or a relay device antenna 30 for a wireless detonation system 1. Therefore, by using a downstream antenna (relay device antenna) 30 with high transmission and reception efficiency, signals can be transmitted and received efficiently between the detonator 10 and the relay device 20. Moreover, the downstream antenna 30 can transmit and receive signals with the detonator 10 loaded in the charge hole 41a of the working face 41 while protruding outside the working face 41. Therefore, it is possible to improve the work efficiency of installing the relay device 20 while ensuring good signal transmission and reception between the relay device 20 and the detonator 10.

[0045] Although the embodiments of the present invention have been described above, it will be apparent to those skilled in the art that many alternatives, improvements, and modifications can be made without departing from the scope of the present invention. Therefore, the embodiments of the present invention may include all alternatives, improvements, and modifications that do not depart from the spirit and scope of the appended claims. For example, the embodiments of the present invention are not limited to the above structure, and may be modified as follows:

[0046] For example, the wireless detonation system 1 can be used in the excavation work of a tunnel 40 as described above. Alternatively, it may be applied to, for example, the destruction of structures such as buildings or excavation work on the seabed. The loading of the detonating cap 10 and the installation of the relay device 20 may be performed manually or, for example, by a loading machine equipped with a robotic arm. A power supply device for charging the detonating cap 10 may be provided on the loading machine. In the above embodiment, an insertion hole 41b is provided in the working face 41 as a hole into which the main body 21 of the relay device 20 is inserted. Alternatively, the main body 21 of the relay device 20 may be inserted into the opening of a single charging hole 41a located, for example, in the center of the working face 41 near the ground.

[0047] In the above embodiment, the first coil 31 and the second coil 32 are circular rings of approximately the same diameter and are arranged approximately coaxially. Alternatively, the first coil 31 and the second coil 32 may be arranged in a polygonal ring shape, such as a square, pentagon, hexagon, etc. For example, the first coil 31 may be smaller than the second coil 32 and disposed on the inner periphery of the second coil 32. The second coil 32 may be smaller than the first coil 31 and disposed on the inner periphery of the first coil 31. For example, the first axis J1 of the first coil 31 and the second axis J2 of the second coil 32 may be approximately parallel rather than coaxial.

[0048] In the above embodiment, the first number of turns of the first coil 31 is 1 to 6. The second number of turns of the second coil 32 is 3 to 30. The first and second numbers of turns may be changed as appropriate as long as the condition that the second number of turns is greater than the first number of turns is satisfied. The winding directions of the first coil 31 and the second coil 32 are not particularly limited and may be any winding direction.

[0049] The resonance capacitor 33 in the above embodiment is attached to the circuit board 22 without being electrically connected to the electronic circuit on the circuit board 22. Alternatively, the resonance capacitor 33 may not be attached to the circuit board 22. A magnetic sheet or the like may be wrapped around the frame member 34 in the above embodiment to facilitate convergence of magnetic flux, and the first coil 31 and the second coil 32 may be wrapped around the outer or inner periphery of the magnetic sheet. The shape of the downstream antenna 30 may be maintained by the strength of the material of the first coil 31 or the second coil 32 without providing the frame member 34.

[0050] In the above embodiment, the downstream antenna 30 of the relay device 20 transmits and receives a signal notifying completion of preparation for detonation and a detonation signal as examples of signals. In addition to these, the downstream antenna 30 may also transmit and receive signals such as a signal for verifying the ID of each detonator 10 loaded in each charging hole 41a and a signal for recording the detonation delay time of each detonator 10. [Explanation of symbols]

[0051] 1. Wireless detonation system 2...Explosive, 2a...Main die, 2b...Additional die 3...blaster, 3a...antenna, 3b...input section, 3c...output section 10...detonator 11...Main body tube 12...electronic circuit, 12a...condenser 13...Electric detonator 14...Antenna (receiving coil) 20...Relay device (for wireless detonation system) 21...Main body 22...circuit board, 22a...control circuit (CPU) 23...Upstream receiving circuit 24...Upstream transmission circuit 25...Downstream receiving circuit 26...Downstream transmission circuit 27…Power supply 28...Upstream antenna 30...Downstream antenna (antenna for repeater) 31...First coil 32...Second coil 33...resonant capacitor, 33a...fixed capacitor, 33b...variable capacitor 34...Frame member 40...Tunnel 41...face, 41a...charge hole, 41b...insertion hole, 41c...sealing member D1,D2…Diameter J1…1st axis, J2…2nd axis

Claims

1. A relay device for a wireless detonation system that relays signals between a blaster and a detonator, an upstream antenna for wirelessly transmitting and receiving signals to and from the blasting device; A downstream antenna is provided for wirelessly transmitting and receiving signals to and from the detonator, and the downstream antenna is a first coil electrically connected to the receiving circuit and the transmitting circuit and wound with a first number of turns; a second coil disposed adjacent to the first coil and substantially coaxially therewith, and wound with a second number of turns greater than the first number of turns; a relay device for a wireless detonation system, the relay device having a resonant capacitor electrically connected to the second coil;

2. 2. The relay device for a wireless detonation system according to claim 1, The first coil and the second coil are annular with a diameter of 300 mm to 1500 mm, the first number of turns is 1 to 6, A relay device for a wireless detonation system, wherein the second number of turns is 3 to 30.

3. 3. A relay device for a wireless detonation system according to claim 1 or 2, The downstream antenna is a relay device for a wireless detonation system that transmits and receives signals from the detonator in the charge hole provided on the face of the tunnel using signals of 1 kHz to 500 kHz.

4. 3. A relay device for a wireless detonation system according to claim 1 or 2, a main body that houses the receiving circuit, the transmitting circuit, and the resonance capacitor; The body is inserted into an insertion hole provided on the working face, A relay device for a wireless detonation system, wherein the first coil and the second coil are held in the main body so as to be positioned outside the insertion hole.

5. 3. A relay device for a wireless detonation system according to claim 1 or 2, A relay device for a wireless detonation system has an annular frame member that holds the first coil and the second coil and is made of an insulating material.

6. 3. A relay device for a wireless detonation system according to claim 1 or 2, A relay device for a wireless detonation system, wherein the first coil and the second coil are coaxial and the axial direction of the coaxial coil is approximately perpendicular to the face of the firing site.

7. A relay device antenna used in the relay device for the wireless detonation system according to claim 1, for wirelessly transmitting and receiving signals to and from the detonator, A relay device antenna having the first coil, the second coil, and the resonance capacitor.

8. A wireless detonation method using the repeater device for a wireless detonation system according to claim 1 or 2 or the antenna for a repeater device according to claim 7.

9. A wireless detonation method using the relay device for a wireless detonation system according to claim 4.

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