KR101870362B1

KR101870362B1 - Mock bomb with display function of drop point

Info

Publication number: KR101870362B1
Application number: KR1020170141402A
Authority: KR
Inventors: 조영준
Original assignee: 고려화공 주식회사
Priority date: 2017-10-27
Filing date: 2017-10-27
Publication date: 2018-06-27

Abstract

The present invention relates to a mock bomb with a display function of a drop point. A body of a container is divided into plural sections to provide an explosion effect of a grenade, and each section is provided with a fluorescent pigment, a fuse head, and a circuit board. When power is supplied from the circuit board, the fuse head is ignited to increase inner pressure therein. The fluorescent pigment is pushed forward by the increased pressure, and thus a plug is opened. Upon opening of the plug, explosive sound is generated, and the fluorescent pigment is sprayed, thereby achieving the explosion effect and displaying a drop point. If the mock bomb is applied to a multiple integrated laser engagement system (MILES), it provides the explosion effect of the grenade and a roadside bomb in a training process, with no destructive power. Moreover, the position of the grenade is displayed, and thus it can be easily recovered, thereby improving concentration of the training and easily recovering the equipment.

Description

{MOCK BOMB WITH DISPLAY FUNCTION OF DROP POINT}

The present invention relates to a depiction charger having a drop point display function, and more particularly, to provide a detonating effect of a grenade, a body of a cylinder is divided into a plurality of bodies, and a fluorescent pigment, When the power is supplied through the circuit board, the ignition jaw is ignited to increase the internal pressure, the fluorescent pigment is pushed forward by the increased pressure, the plug is opened, and the fluorescent pigment is sprayed together with the blowing due to the opening of the plug, And the drop position display can be performed at the same time. Especially, it is applied to the mile equipment to provide the explosive effect of the grenade and the explosion of explosion without destructive power in the training process, and the position of the grenade can be displayed to facilitate the recovery, so that the concentration of training and the recovery of equipment are easy. will be.

In general, grenades and Improvised Explosive Devices (IEDs) are a kind of military weapons capable of killing people or destroying buildings. These grenades and rapid-fire explosives are one of the weapons commonly used in close combat when actual combat occurs. Therefore, the grenade launcher and the explosion-proof explosive should be fully familiarized to improve the utilization in the case of battle. However, the grenades and the explosives are very difficult to be used for training due to injury or killing.

Thus, grenade launchers and training improver explosives were provided instead of actual grenades and rapid explosives, providing explosive sounds but not destructive forces.

In recent years, however, the MILES System, which uses advanced electronic equipment, has been introduced to limit the activity by measuring the degree of injury of training participants by adding a range of killings to the weapon. Respectively.

The Miles system is used to determine whether or not to participate in simulated combat by determining whether to fire the laser light instead of the bullet. For example, when a soldier in training enters a target and triggers a trigger on a personalizer or a publicizer, a sensor mounted on the trigger recognizes the trigger pulling, or a sound or light emitted when the loaded blanket or the like is fired is detected by an acoustic sensor The sensor senses and activates the laser launcher attached to the soldier's firearm, from which a pulsed infrared laser is launched to the aimed target. If the fired laser hits all or a portion of a plurality of sensing elements of a sensing device mounted on the outside of a target such as a harness or harness on the helmet and body of each soldier, The signal is converted into an electric signal, and the signal is recognized as a shot signal. The signal is displayed visually and audibly with a warning light mounted on the soldier's body in accordance with the determined logic. At the same time, Ali is configured to send signals to a remote central control system to centrally control the attack.

In addition, the grenade in the Miles system formed a large number of light emitting parts on the outer surface of the grenade body beyond the conventional explosion mode, and judged whether the grenade was damaged according to the degree of light irradiation and receiving the light within a certain range.

However, since the above-mentioned Miles-type training grenade is designed to detect a sensor through a flash, a means for generating a smoke or an explosion sound is further required in order to provide an explosion effect of the grenade. In addition, since the mileage training grenade is an expensive device equipped with various sensor devices, it generates GPS and a beep sound to facilitate recovery after thrown. There is a drawback in that the recovery time is long.

In the grenade for training of Korean Patent Registration No. 10-0768428 (Registered on October 12, 2007, hereinafter referred to as 'Prior Art Document 1'), a body is formed with a synthetic resin and the inside of the body is filled with ore powder, and a notch is formed on the outer surface of the body. The explosive effect is expressed by scattering the ore powder filled in the inside while making the body tear easily during the explosion. These training grenades provide the effect of improving the performance of the training by providing the effect of using the grenades which is comparatively safe because they do not have the destructive power. However, it is difficult to control the range of the killings, It is difficult to apply to the Miles system.

Korean Registered Patent No. 10-0665185 (Registered on Dec. 28, 2006, hereinafter referred to as 'Prior Art Document 2') presented an antitank mock shot. The prior art 2 includes a body of which both sides are opened with a predetermined diameter and a length, a separating wall partitioning the inside of the body by an ignition part and a power source part, a smoke film filling the ignition part, And an end of a power line connected to the end of the power source of the body and connected to the end of the power source unit is connected to the end of the power source line connected to the power source unit side of the body, Wherein the protruding portion is formed on an outer circumferential surface of the simulated carbon to be connected to a support of the coupled body coupled to the electric train.

However, in the prior art 2, explosion of a simulated shot is performed by a power source to enhance the electric field effect. However, since the assembled body for mounting the simulated gun is fixed to a train, it is used differently from a grenade to be used.

Therefore, it is necessary to study a new type of descriptive shot which can facilitate the recovery of grenade as well as providing a bomb when applied to training grenades to be used.

Korean Registered Patent No. 10-0768428 (registered on October 12, 2007): Training grenade Korea Registered Patent No. 10-0665185 (registered on December 28, 2006): Antitank

Accordingly, the depiction shot having the drop point display function according to the present invention,

And is designed to be detachably inserted into a chamber of a grenade body to which a Miles system is applied, and is provided with a power supply of a grenade, and ignited and exploded.

According to an aspect of the present invention,

A pilot gun mounted on a chamber of a training grenade for a Miles system equipped with a plurality of light emitting sensors on its outer surface to provide an explosion effect due to the occurrence of bouncing, characterized in that a partition wall is formed inside the cylindrical body so as to be deflected toward one end, A body divided into a first chamber of a space and a second chamber of a narrow space; A disk-shaped packing which is inserted into the first chamber to divide the first chamber into an active portion and an expanded portion, and prevents flow of packing in the active portion; An ignition jaw assembly including ignition jets being a bundle of ignition agents disposed in the expanding portion of the first chamber, and a twin core wire having one end connected to the ignition jaw and extended to the second chamber through the conduit tube port of the partition; A fluorescent pigment filled in the charging part of the first chamber of the body and indicating the position of the explosion by ignition; A cap installed at an end of the body, the first chamber being formed at both ends thereof to block the inside and outside of the body to prevent moisture absorption; And a circuit board fixed to an end portion of the second chamber of the body at which the second chamber is formed and a front end of the ignition jam assembly is coupled to supply electric power supplied from the outside to the electric wire.

In addition, the outer surface of the body may be formed with an annular protrusion protruding along the circumferential surface, and may be formed to be deflected in the direction of the end of the first chamber in the longitudinal direction of the body, thereby determining the position of the first chamberized second chamber.

In addition, the ignition jam assembly includes two conductor wires, two conductor wires projected from the front ends of the two conductor wires, and a beam splitter interposed between the conductor wires to maintain a constant interval between the two conductor wires. A welding portion for integrally connecting the beam conductor and the conductor wire by soldering welding or spot welding; a heat generating rod for connecting the front end portions of the two conductor wires to each other to generate heat by power supply; .

In addition, the fluorescent pigment to be filled in the live part of the first chamber may use a red fluorescent pigment for easy identification in an electric field environment of the soil and the gravel field.

In addition, a cap seal layer may be further formed on the upper surface of the cap to cover the joint portion between the cap and the body to seal the inside of the cap.

In addition, the stopper may cut the upper edge of the upper surface in the direction of being exposed to the outside to increase the edge thickness of the stopper seal layer covering the upper surface of the stopper, thereby increasing the edge sealability. The inner groove of the stopper may have a cylindrical shape or a conical shape or a truncated cone shape whose diameter decreases toward the inner side from the bottom of the stopper.

The depiction shot having the drop point display function of the present invention by the above-

It can be easily detached and attached to the chamber of the grenade using the Miles system.

In addition, the ignition method of the descriptive charcoal can be minimized by using a power supply system in which ignition and explosion are performed by directly supplying a power source used for sensor operation inside a grenade than a conventional hitting method.

In addition, it is possible to provide a grenade explosion effect by generating explosion while minimizing the explosion force, and it is possible to provide a kill range by the light emitting sensor or the acoustic sensor of the Miles-type training grenade, and prevent injury by explosion.

In addition, it has become possible to provide a safe training environment, such as facilitating the recovery of grenades thrown by the fluorescent material emitted in the explosion of the depicted shot, and to provide a useful device that can facilitate the recovery of expensive equipment.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross-sectional view of a depiction of an embodiment according to the present invention; FIG.
2 is a cross-sectional view of an ignition jam assembly according to an embodiment of the present invention.
3 is a cross-sectional view illustrating a stepped body according to an embodiment of the present invention.
4A and 4B are cross-sectional views of a main part showing an embodiment of a cap and a cap sealing layer according to the present invention.
Figures 5A-5C are cross-sectional views illustrating various embodiments of a stop formed with grooves according to the present invention.
FIG. 6 is a schematic sectional view showing an example in which a descriptive shot according to the present invention is applied to a training grenade for a Miles system; FIG.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail with reference to the accompanying drawings. It should be understood, however, that the appended drawings illustrate only the contents and scope of technology of the present invention, and the technical scope of the present invention is not limited thereto. It will be apparent to those skilled in the art that various changes and modifications can be made within the scope of the technical idea of the present invention based on these examples.

1 is a cross-sectional view illustrating a depiction of an embodiment according to the present invention.

As shown, the depiction charger 10 having a drop point display function according to the present invention includes a body 20 having a plurality of internal compartments formed therein, an ignition jaw assembly 30 installed in a space inside the body, And a pigment 50.

First, the body 20 is cylindrical and has a diameter similar to the inner diameter of the chamber of the grenade to which it is to be used. The body 20 can be applied to a suds explosive as well as a grenade.

The body 20 has a partition wall 21 formed at an inner middle portion thereof to partition the internal space into a first chamber 22 and a second chamber 23 and preferably to deflect the partition wall from the inner space to the rear end portion The space for accommodating the first chamber 22, which is the front space defined by the partition walls, can be formed larger than the second chamber 23. For example, the interior of the body can be divided into three equal parts, so that the first chamber and the second chamber can be partitioned at a ratio of 2: 1.

The first chamber 22 may be provided with a packing 40 to partition the space of the first chamber 22 into a charging part 221 at the front end side and an expansion part 222 at the rear end side, . The packing may be arranged to form a step on the inner surface of the body so as to be positioned on the step. In this case, it is preferable that the step is formed such that the diameter at the front end side is larger than the diameter at the rear end side, so that the packed body can be pushed toward the front end side by the pressure at the rear end side.

The charging part 221 of the partitioned body is filled with the fluorescent pigment 50 for displaying the position and the circuit board 70 receiving power from the outside is placed in the second chamber.

A conduit tube 211 is formed in the partition 21 so that a wire 32 of an ignition jam assembly 30 described below is connected to the expansion part 222 and the second chamber 23 of the first chamber 22 The wiring can be connected. The conduit pipes 211 may be formed into one so that the two-core wires are inserted, or the conduit pipes are divided into two, so that the two-core wires can be separated and individually inserted. The partition 21 may be integrally formed with the body or may be separately formed and inserted into the body, and then may be firmly coupled to the body through fixing means such as silicone or an attachment means.

Further, an annular projection 24 may be formed on the outer surface of the body 20 so as to protrude along the circumferential surface at one side of the longitudinal direction (axial direction) of the body. The annular protrusion 24 shown in the figure is deflected in the direction of the front end filled with the fluorescent pigment so that the grenade used or the explosion explosion is inserted into the chamber in the chamber, As shown in FIG. That is, when the front end side having the first chamber 22 is first inserted into the chamber, since the length from the first chamber end to the annular projection is short, the annular protrusion is caught by the engagement portion of the chamber entrance, In addition, it is possible to prevent the mounting failure caused by inserting the back and forth direction in advance, as well as to prevent the mounting failure because the front and rear directions of the description bullet can be recognized as the annular protrusion during the nighttime training without light.

In addition, the filling part 221 of the first chamber 22 is filled with a fluorescent pigment 50 for displaying a position. The fluorescent pigment uses a pigment harmless to the human body. In addition, the fluorescent pigment may be mixed with a reflective cut paper obtained by cutting a reflection paper into a small piece so as to reflect light, thereby enabling position confirmation by light reflection. In this case, the reflective cut sheet is preferably cut in a range of 1 to 3 mm in width and 10 to 20% in volume based on 100% by volume of the total charged portion of the charger. When the amount is less than 10% by volume, it is difficult to obtain a light reflecting effect because the reflection amount is low. When the amount is more than 20% by volume, the amount of the fluorescent pigment may be decreased to hinder the position confirmation by the fluorescent pigment. Do.

A circuit board 70 is installed at the end of the second chamber 23. The circuit board is a substrate connected to external power supply means and supplied with power from the outside. The circuit board may have a function of simply supplying an external power to the circuit board, and a control function to provide an external power source to the internal circuit when the external power is supplied.

As described above, the ignition jaw assembly 30 is mounted inside the body 20 defined by the charging part 221, which is the first chamber 22, and the expansion part 222 and the second chamber 23.

The ignition jaw assembly 30 is composed of an ignition jaw 31 having an ignition agent as an ignition powder and a two-core electric wire 32 for supplying power to the ignition jaw. The two-core wires 32 are each made of a conductive material having a different polarity, and are covered with a conductor covering the center conductor wire and the conductor wire.

In the above configuration, the ignition jaw 31 is placed in the expansion part 222 of the first chamber 22 of the body, and when the ignition is performed, explosive sound and overpressure are transmitted to the charging part 221 to inject the charged fluorescent pigment into the charging part . The two-core wire 32 has one end connected to the ignition jaw 31 and the other end connected to the circuit board 70 provided at the end of the second chamber 23 through the conduit tube of the partition 21 do. The two-core wire 32 is heated by the electric power supplied from the circuit board 70 so as to ignite the ignition jaw 31 to be ignited. The two-core electric wire 32 is directly connected to the ignition jaw to generate ignition, So that ignition of the ignited jade can be performed through the heat generating rod.

2, the ignition pad assembly 30 includes a heating rod 33 and a portion of the conductor line 35 inserted in the ignition pad 31 so that the heating rod is exposed to the front of the two-core wire 32 When the power is supplied to the heat generating rod 33 through the electric wire, resistance heat is generated in the heat generating rod, and the ignition jade 31 is ignited by the resistance heat, The inflated portion 222 is in a high pressure state and the pressure in the high pressure state presses the fluorescent pigment 50 filled in the charging portion 221 through the packing 40 to eject the fluorescent pigment to the front end side, .

Here, the resistance value of the heat generating rod 33 varies depending on the length of the heat generating rod and the distance between the two conductor wires 35. Therefore, in order to keep the resistance value constant, a Beck light 34, which is an insulating material, is inserted between the two conductor lines 35, and the two conductors are joined by soldering or spot welding to form the weld 36, And the length of the heat generating rod connecting the two conductor lines can be maintained constant, so that the resistance value can be kept constant. This is because the power output from the Miles device is constant. If the resistance value deviates greatly, it will cause the failure according to the resistance value, so it can be completely eliminated.

In addition, when the heating rod 33 is made of platinum wire, disconnection of the platinum wire occurs during ignition of the ignition jacket due to heat generation, so that only the conventional ignition lock 31 is ignited and the heating rod 33 is not disconnected. It is possible to completely eliminate the occurrence of a high rate of defect rate in checking whether the grenade operates normally. As the insulating material interposed between the two conductor wires, various insulating materials may be used in addition to the above-mentioned Beckite, and various known materials other than platinum wires may be used as the heating rod.

In addition, a conduit passage closure layer 212 may be formed on a surface of the partition 21 where the second chamber is formed in order to remove a gap in the conduit tube passage 211 through which the two-core wire is passed. The conduit passage sealing layer 212 may be formed of an insulating material or silicon to block an ignition explosion of the first chamber expanding portion or an explosive gas or a combustion gas in ignition from entering the second chamber, It is possible to prevent deterioration of the loud sound power generated upon discharge to the end of the first chamber.

Next, the packing 40 divides the first chamber 22 of the body 20 into the charging part 221 and the expansion part 222 to prevent the flow of the charged fluorescent pigment. The packing 50 may be formed to have the same or similar size as the first chamber inner diameter of the body so as to be fixed to prevent the flow of the fluorescent pigment, but may be pushed and discharged in the end direction by the generated gas during the explosion.

3, a step 25 is formed on the inner surface of the body where the packing is disposed to limit the depth of insertion of the packing from the front end side to the rear end side of the body while the packing is easily discharged to the front end side of the body at the time of pressure generation Lt; / RTI >

A stopper (60) is further provided at an end of the first chamber (22) of the body (20) to seal the first chamber. The cap 60 may be provided in the form of a cap that partially encloses the body end and may form a step 26 on the inner circumferential surface of the first chamber as shown and may be coupled to the step 26 .

The plug may be coated with an adhesive on the side contacting the inner surface of the body so that the inner surface of the plug may be sealed by attaching the side surface of the plug and the inner surface of the body.

4A, a closure sealing layer 61 sealed with an ABS adhesive may be formed on the front end side of the stopper 60 to seal the inside of the body. In this way, the plug 60 and the closure sealing layer 61 can seal one end of the first chamber, thereby preventing occurrence of defective ignition of the dispersion amount or the ignition jelly when discharging the filled fluorescent substance by moisture absorption.

In addition, as shown in FIG. 4B, the upper surface edge of the cap 60 may be cut to increase the thickness of the closure closure layer 61 at the corner portion of the cap. When the thickness of the edge of the plug seal layer 61 is increased, the contact area between the plug seal layer and the inner surface of the body is increased to improve the sealability of the plug seal layer. This provides an effect of increasing the explosion sound generated at the moment of opening by opening the stopper only at a pressure of a certain level or more while preventing the stopper from opening until the explosion pressure generated inside the body is increased to a certain size. At this time, the cutting should be in a range of ½ of the thickness of the stopper. If the thickness of the stopper is increased to 1/2 or more of the thickness of the stopper, the structural strength of the stopper may be lowered and the resistance due to the side load may be lowered to cause distortion.

The stopper (60) may have an inner groove (62) formed on a lower surface thereof facing the charging part (221) so that the inner pressure acts on the outer side toward the front side through the inner groove.

That is, in the cap 60, a large pressure is applied to the central portion where the grooves 62 are formed than the edges, so that a uniform load is transmitted to the edges so that the portions bonded to the body are temporarily separated. It is possible to concentrate the discharge of the pressure, thereby providing an effect of improving the explosion sound. This is to minimize the partial leakage of the explosion pressure by opening a part of the edge of the plug first.

The shape of the inner groove 62 formed on the bottom surface of the cap 60 may be a cylindrical shape as shown in FIGS. 5A to 5C, a cone or a truncated cone having a smaller diameter toward the inside, So that the center portion of the cap is pushed outward and the edge is separated from the inner surface of the body. Also, although not shown, the inner groove of the stopper may include polygonal horns or polygonal horns and may be formed in various shapes such that the inner pressure is applied to the center portion of the stopper first.

FIG. 6 is a schematic sectional view showing an example in which the depicted charcoal according to the present invention is applied to a training grenade for a Miles system.

As described above, the training grenade 90 is loaded with a battery in the power supply chamber 91 and the depicted charger 10 of the present invention is mounted in the adjacent chamber 92.

The depiction charger 10 is inserted from the lower part of the training grenade, and the end where the circuit board is exposed is first inserted into the chamber, and power is supplied from the power supply room through the circuit board.

At this time, the training grenade (90) is provided with a control unit (93), and when an operation signal is transmitted, power is supplied from the power supply room (91) to each light emission sensor (94) Power is supplied to the substrate to ignite the ignition jaw to generate the bell sound.

Here, the actuating signal may be a signal from which the illustrated lever 95 is separated. That is, the control unit 93 controls the light emitting sensor 94 and the descriptive charger 10 to supply the power received from the power supply room 91 by the signal generated when the lever is separated. At this time, the power supply to the light emitting sensor and the descriptive bullet may be supplied after a certain time after receipt of the separation signal of the lever, so that the explosion effect can be provided with a time difference.

Of course, in addition to the power supply through the control unit, the power supply room and the circuit board of the depicted charger are directly connected to each other so that the power supply is always connected. When the operation signal is received, The heating rod is energized and supplied to the heating rod 33. The heating rod quickly generates resistance heat of high temperature by the supplied electric current to ignite the ignition jam 31. The ignition jade is ignited, A gas is generated to generate an expansion pressure in the expansion part 222. The expansion pressure pushes the fluorescent pigment 50 filled in the charging part 221 through the packing 40 and pushes the fluorescent pigment 50 to the outside, The plug 60 is separated from the body, and the fluorescent pigment is ejected into the separated space, and the inflated gas is discharged at the same time, causing the explosion.

As described above, the training grenade 90 with the Miles system is operated to eject the fluorescent pigment 50 while providing flashing and bouncing in operation, so that the grenade can be easily recovered by confirming the discharged fluorescent pigment, . In addition, by providing a certain amount of bouncing, it is possible to generate an effect of popping the actual grenade, so that the training effect can be enhanced, and the preparation for the war can be thoroughly performed.

10: Description Tan
20: Body
21: partition wall 22: first chamber
23: second chamber 24: annular projection
25, 26:
211: conduit conduit 212: conduit conduit sealing layer
221: live part 222:
30: Ignition spool assembly
31: Ignition Jade 32: Wires
33: Heating rod 34: Becklight
35: conductor line 36: welded portion
40: Packing
50: Fluorescent pigment
60: Plug
61: seal closure layer 62: groove
70: circuit board
90: Training grenade
91: Power supply room 92: Chamber
93: control unit 94:
95: Lever

Claims

A description is provided of a training grenade for a Miles system equipped with a plurality of light emitting sensors on its outer surface,
A partition wall 21 is formed inside the cylindrical body so as to be deflected toward one end of the cylindrical body so as to divide the inside of the cylindrical body into a first chamber 22 having a large space and a second chamber 23 having a narrow space, A body 20 having a passageway 211 formed therein to communicate the first chamber and the second chamber, and a step 25 formed on the inner surface of the first chamber;
A disk-shaped packing 40 for dividing the first chamber 22 into the charging part 221 and the expansion part 222 and preventing the packing of the filling part from flowing;
An ignition jaw 31 as an ignition agent bundle disposed in the expansion portion of the first chamber and a two-core wire 32 connected at one end to the ignition jaw and extending to the second chamber through the conduit tube of the partition wall An ignition lock assembly 30;
A fluorescent pigment (50) filled in a charging part of the first chamber of the body and indicating a location by an explosion by ignition, and using a red fluorescent pigment to facilitate identification in an electric field environment of the soil and the gravel field;
A cap 60 installed at an end of the body at the first end of the body to block the inside and outside of the body to prevent moisture absorption;
And a circuit board (70) fixed to an end portion of the second chamber of the body, the front end of the ignition jam assembly being coupled to supply electric power supplied from the outside to the electric wire,
A plug sealing layer 61 is formed on the upper surface of the cap 60 to cover the joint portion of the cap and the body in the front end direction and to seal the inside of the cap,
The stopper (60) cuts the upper surface corner in the outward direction to increase the edge thickness of the stopper seal layer (61) covering the upper surface of the stopper to increase the edge sealability,
Wherein the second chamber is formed with a conduit passage sealing layer (212) on the partition wall surface defining the second chamber to remove a gap in the conduit tube through which the two-core wire penetrates.

The method according to claim 1,
The body 20 is formed with an annular protrusion 24 protruding along a circumferential surface thereof. The annular protrusion 24 is formed to be deflected in the longitudinal direction of the body toward the end of the first chamber so as to discriminate the positions of the first chamber and the second chamber Describing features featuring one.

The method according to claim 1,
The ignition jam assembly 30 includes two twisted wires 32, two conductor wires 35 extending in front of the twisted wires and disposed in parallel with each other, A welding portion 36 for integrally connecting the beam and the conductor wire by soldering or spot welding, and a welding portion 36 for connecting the front end portions of the two conductor wires to each other to generate heat by power supply And an ignition jaw (31) coupled to enclose the heat generating rod (31).

delete

The method according to claim 1,
Wherein the stopper (60) has an inner groove (62) formed in a lower surface thereof facing the charging part so that the inner pressure acts in an outward direction through the inner groove.

8. The method of claim 7,
Characterized in that the inner groove (62) of the cap is formed in a cylindrical shape or a conical shape or a truncated cone shape whose diameter becomes narrower toward the inner side from the bottom surface of the plug.