FILLING RESIN IN CLOSURES

[Technical Field] [0001]

The present disclosure relates to a boring tool, a boring device, and a boring methods for forming an opening in a closure disposed in a connecting section or the like of a communication cable, and methods of filling resin in closures [Background]

[0002]

In a communication cable laid in a conduit or a manhole buried underground, the intrusion of water and other substances from the outside into the cable can be prevented by feeding gas such as dry air or nitrogen, having pressure higher than the atmospheric pressure into the cable. [0003]

However, an underground cable has a problem in that, because the environment of the underground cable is harsh, the connecting section can be damaged and leaks can easily occur in the connecting section. In order to cope with such a problem, there has been known a method for repairing a connecting section of a communication cable and smoothly polishing one or more leaking portions of the connecting section, and bonding stainless steel foil to the one or more leaking sections (Patent

Document 1). [0004]

[Prior Art Document List]

[Patent Document]

[Patent Document 1 ] Japanese Patent Laid-Open Publication No. 2016-158415

Summary

[0005]

On the other hand, in order to prevent or repair leaks due to damage to or deterioration of a closure, which is a hollow protection tool, covering a connecting section or a branching section of a cable, a gas leak preventing method for filling resin in the closure set in the site is conceivable.

[0006]

To fill the resin in the closure set in the site, an opening functioning as a passage for filling the resin is provided on a wall surface of the closure. However, as explained above, the inside of the closure in which the communication cable is connected is set in a pressurized state by gas, such as dry air or nitrogen, having pressure higher than the atmospheric pressure fed into the communication cable. Therefore, when an opening is provided on the wall surface of the closure, a problem could occur in that high-pressure leaks form, particularly when a pressure drop occurs in the entire communication cable.

[0007] In a manhole in which such a closure is set, usually, closures are congested and set in upper and lower parts of the manhole. There is also a problem in that it is difficult to use large tools and workers are often forced to work with unnatural postures.

[0008]

Further, in filling the resin in the closure, the resin is preferably quickly filled while managing the filling pressure of the resin to prevent the closure from being broken by the pressure of the filled resin.

[0009]

The embodiments disclosed herein provide a boring tool that does not cause a pressure drop in a closure during boring.

[0010] The embodiments disclosed herein further provide a boring device or a boring method that is compact and which can form an opening in a closure, while avoiding a pressure drop on the inside with simple operation.

[0011]

Further, the embodiments disclosed herein provide a method of quickly filling fluid resin in a closure in which an opening is formed.

[0012]

One aspect of the disclosure is directed to a boring tool for forming an opening in a closure that covers a part of a communication cable and in which gas having pressure higher than pressure of outside air is supplied, the boring tool includes: a cylindrical main body, a cutting section provided at one end in an axial direction of the cylindrical main body; and a valve connected to another end of the cylindrical main body, wherein the cylindrical main body includes a male screw-like cutting tap section provided on an outer circumferential surface, the cutting tap section being disposed in a region extending from a first end side portion of the cylindrical main body toward the other end side.

[0013]

With such a configuration, as the cutting section at the distal end of the cylindrical main body penetrates into a sidewall of the closure, the male screw-like cutting tap section provided on the outer circumferential surface of the cylindrical main body airtightly penetrates into a wall surface of the closure. Therefore, an airtight state is maintained between the outer circumferential surface of the cylindrical main body and the wall of the closure. Pressurized gas on the inside of the closure is prevented from leaking from between the outer circumferential surface of the cylindrical main body and the wall of the closure.

[0014] According to another preferred aspect of the disclosure, the valve is coupled to the cylindrical main body via a screw section formed on the other end side of the cylindrical main body. [0015]

With such a configuration, it is easy to attach a valve used in filling resin in the cylindrical main body [0016] According to another preferred aspect of the disclosure, the cutting section includes a plurality of cutting blades disposed separately in a circumferential direction at an annular distal end portion of the cylindrical main body [0017]

With such a configuration, since chips formed when a sidewall of the cylindrical main body is cut are stored in the opening, the cutting is smoothly performed.

[0018]

According to another preferred aspect of the disclosure, a wrench coupling section is provided on the other end side of the cylindrical main body [0019] With such a configuration, by coupling a tool such as a wrench to the wrench coupling section and rotating the cylindrical main body with the wrench or the like, it is possible to drive the cutting section toward a wall of the closure and form an opening in the wall of the closure.

[0020]

According to another aspect of the disclosure, there is provided a boring device for forming an opening in a closure that covers a part of a communication cable, the boring device including: a boring tool for forming an opening in an outer circumferential wall of the closure; and a positioning tool for positioning the boring tool with respect to an outer circumferential wall of the closure, wherein the boring tool includes: a cylindrical main body, a cutting section being provided at one end in an axial direction of the cylindrical main body, and a valve connected to another end of the cylindrical main body, the cylindrical main body includes a male screw-like cutting tap section provided on an outer circumferential surface, the cutting tap section being disposed in a region extending from a one end side portion of the cylindrical main body toward the other end side, the positioning tool includes a guide member that is positioned on an outside of the outer circumferential wall of the closure and guides the boring tool, and the guide member includes a guide opening, a female screw being formed in an inner circumference of the guide opening, the female screw being screwed with the male screw-like cutting tap section provided on the outer circumferential surface of the boring tool. [0021]

With such a configuration, since the boring tool can be positioned with respect to the outer circumferential wall of the closure by the positioning tool, it is possible to efficiently form the opening in the closure even in a narrow space.

[0022] According to another preferred aspect of the disclosure, the positioning tool includes a disposing tool for disposing the guide member on the outside of the outer circumferential wall of the closure.

[0023]

According to another preferred aspect of the disclosure, the disposing tool is a band -like member wound along the outer circumferential surface of the closure, and the guide member has a tabular shape and is provided as a part of the band-like member.

[0024]

According to another preferred aspect of the disclosure, the guide member includes an O-ring disposed at a circumferential edge of the guide opening of a surface opposed to the closure during the positioning.

[0025]

With such a configuration, since the O-ring is disposed in a radial direction outward position of the boring tool during boring, it is possible to prevent a leak of high-pressure gas from the inside of the closure during the boring. [0026]

According to another aspect of the disclosure, there is provided a boring method for boring a closure that covers a part of a communication cable and to which gas having pressure higher than pressure of outside air is supplied, the boring method boring the closure using a boring device for forming an opening in the closure, the boring device including: a boring tool for forming an opening in an outer circumferential wall of the closure; and a positioning tool for positioning the boring tool with respect to an outer circumferential wall of the closure, the boring tool including: a cylindrical main body, a cutting section being provided at one end in an axial direction of the cylindrical main body, and a valve connected to another end of the cylindrical main body, the cylindrical main body including a male screw-like cutting tap section provided on an outer circumferential surface, the cutting tap section being disposed in a region extending from a one end side portion of the cylindrical main body toward the other end side, the positioning tool including a guide member that is positioned on an outside of the outer circumferential wall of the closure and guides the boring tool, and the guide member including a guide opening, a female screw being formed in an inner circumference of the guide opening, the female screw being screwed with the male screw-like cutting tap section provided on the outer circumferential surface of the boring tool, the boring method including: a step of disposing the guide member of the positioning tool of the boring device to be opposed to an outer circumferential surface of the closure; a step of screwing, in the female screw section of the guide opening of the guide member, the male screw-like cutting tap section provided in an outer circumference of the cylindrical main body of the boring tool; a step of rotating the cylindrical main body of the boring tool and moving the boring tool in an outer circumferential surface direction of the closure with respect to the guide member; a step of rotating the cylindrical main body of the boring tool and causing the cutting section of the boring tool to penetrate into a sidewall of the closure; and a step of rotating the cylindrical main body of the boring tool and causing the cutting section of the boring tool to pierce through the sidewall of the closure. [0027]

According to another preferred aspect of the disclosure, the boring method further includes a step of reversely rotating the cylindrical main body of the boring tool after the sidewall is pierced through and dischaiging, from the cylindrical main body, a part of the sidewall of the closure cut off from the closure and housed at one end of the cylindrical main body of the boring tool. [0028]

According to another preferred aspect of the disclosure, the boring method includes a step of forming, prior to the disposition of the boring tool, in the sidewall of the closure, a prepared hole having an inner diameter smaller than an outer diameter of the cutting section of the boring tool.

[0029] According to another aspect ofthe disclosure, there is provided a method of filling fluid resin in an inside of a closure that covers a part of a communication cable and to which gas having a pressure Psys higher than pressure of outside air is supplied, withstand pressure of the closure being pressure Pmax, a press-in port into which the resin is injected and a reliefport for emitting the gas in the closure being provided in the closure, the method including: a step of closing an on-off valve provided in the press-in port and an on-off valve provided in the relief port and connected to an automatic relief valve automatically opened at the pressure Psys; a step of opening the on-off valve connected to the relief port and the on-off valve provided in the press-in port, pressure-feeding the resin into the closure through the press-in port at the pressure Psys or more and the pressure Pmax or less, and filling the closure with the resin; and a step of confirming that the resin flows out from the relief port and closing the on-off valve provided in the open port and the on-off valve in the press-in port.

[0030]

According to another preferred aspect of the disclosure, the closing of the on-off valve provided in the press-in port is performed after the on-off valve provided in the relief port is closed. [0031] According to another preferred aspect of the disclosure, the filling method further includes a step of continuing to pressure-feed, after the closing of the on-off valve provided in the relief port, the resin into the closure at the pressure Psys or more and the pressure Pmax or less through the press-in port in a state in which the on-off valve provided in the press-in port is opened.

[0032] According to another preferred aspect of the disclosure, a step of closing the on-off valve provided in the press-in port after the closing of the on-off valve provided in the relief port is executed immediately before or when the pressure of the closure reaches Pmax.

[0033]

According to another aspect of the disclosure, there is provided a method of filling fluid resin in an inside of a closure that covers a part of a communication cable and to which gas having pressure

Psys higher than pressure of outside air is supplied, withstand pressure of the closure being pressure Pmax, a press-in port into which the resin is injected and a reliefport for emitting the gas in the closure being provided in the closure, the method including: a step of closing an on-off valve provided in the press-in port and an on-off valve provided in the relief port, an automatic relief valve automatically opened at the pressure Psys or more and the pressure Pmax or less being connected to the on-off valve; a step of opening the on-off valve provided in the relief port and the on-off valve provided in the press-in port, pressure-feeding the resin into the closure through the press-in port at the pressure Pmax or more, and filling the closure with the resin; and a step of confirming that the resin flows out from the relief port and closing the on-off valve provided in the press-in port.

[0034]

According to another aspect of the disclosure, there is provided a method of filling fluid resin in an inside of a closure that covers a part of a communication cable and to which gas having pressure Psys higher than pressure of outside air is supplied, withstand pressure of the closure being pressure Pmax, a press-in port into which the resin is injected and a reliefport for emitting the gas in the closure being provided in the closure, the method including: a step of closing an on-off valve provided in the press-in port and an on-off valve provided in the reliefport, an automatic relief valve automatically opened at the pressure Psys being connected to the on-off valve; a step of opening the on-off valve provided in the relief port and the on-off valve provided in the press-in port, injecting, into the closure, through the press-in port, the resin pressure-fed from a resin supply source, a resin supply pressure of which is set to pressure higher than Pmax, and filling the closure with the resin; a step of confirming that the resin flows out from the re lief port and reducing the resin supply pressure from the resin supply source; and a step of closing the on-off valve provided in the relief port when the resin supply pressure from the resin supply source is reduced to Pmax or less.

[0035]

According to the disclosure, a boring tool that does not cause a pressure drop in a closure during boring is provided. [0036]

According to the disclosure, a boring device or a boring method that is compact and can form an opening in a closure while avoiding a pressure drop on the inside with simple operation is provided. [0037]

Further, according to the disclosure, a method of quickly filling fluid resin in a closure in which an opening is formed is also provided.

Brief Description of Drawings [0038]

[Figure 1 ] Figure 1 is a perspective view of a boring tool in a preferred embodiment. [Figure 2] Figure 2 is a longitudinal cross-sectional view of the boring tool shown in Figure 1.

[Figure 3] Figure 3 is a perspective view of a boring device for use with the preferred embodiment of the boring tool shown in Figure 1.

[Figure 4] Figure 4 is a perspective view of a guide member of the boring device for use with the preferred embodiment of the boring tool shown in Figure 1.

[Figure 5] Figure 5 is a schematic perspective view showing a state in which the boring device shown in Figure 1 is wound and fixed on the outer circumference of a closure.

[Figure 6] Figure 6 is a diagram that illustrates a boring method by the boring device of the preferred embodiment.

[Figure 7] Figure 7 is a diagram that illustrates the boring method by the boring device of the preferred embodiment. [Figure 8] Figure 8 is a diagram that illustrates the boring method by the boring device of the preferred embodiment.

[Figure 9] Figure 9 is a diagram that illustrates the boring method by the boring device of the preferred embodiment.

[Figure 10] Figure 10 is a diagram that illustrates the boring method by the boring device in the preferred embodiment.

[Figure 11] Figure 11 is a diagram illustrating the boring method by the boring device in the preferred embodiment.

[Figure 12] Figure 12 is a diagram that illustrates a configuration for implementing a filling method for embodiments disclosed herein. [Figure 13] Figure 13 is a flowchart that illustrates the filling method for embodiments disclosed herein.

[Figure 14] Figure 14 is a flowchart that illustrates an alternative filling method for embodiments disclosed herein.

[Figure 15 ] Figure 15 is a diagram that illustrates a configuration for implementing a filling method for embodiments disclosed herein.

[Figure 16] Figure 16 is a flowchart that illustrates the filling method for embodiments disclosed herein.

Detailed Description [0039]

A boring tool 10 in a preferred embodiment, as will be explained below with reference to the drawings. Figure 1 is a perspective view of the boring tool 10 in the preferred embodiment. Figure 2 is a longitudinal sectional view of the boring tool 10.

[0040]

The boring tool 10 in this embodiment is a boring tool that forms an opening in a sidewall of a closure that covers a connecting section or a branching section of a communication cable (an underground cable) set on the inside of a manhole, high-pressure gas being supplied to the inside of the communication cable.

[0041]

As shown in Figure 1 and Figure 2, the boring tool 10 includes a cylindrical main body 14, at one end in the axial direction of which a cutting section 12 is provided, and a valve 16 connected to the other end of the cylindrical main body 14. [0042]

The cylindrical main body 14 includes a main body channel 18 piercing through the cylindrical main body 14 and extending in the axial direction and a male screw-like cutting tap section

20 provided on the outer circumference. The cutting tap section 20 is disposed in a region extending from one end portion to the other end side of the cylindrical main body 14.

[0043] In this embodiment, the cutting tap section 20 is disposed in a region starting from near the distal end of the cutting section 12 and extending toward the other end side of the cylindrical main body 14.

[0044]

However, the cutting tap section 20 is preferably not disposed in the region starting from near the distal end of the cutting section 12 and may be disposed in a region starting from a portion located further on the other end side of the cylindrical main body 14 than the proximal end of the cutting section 12. In detail, the cutting tap section 20 only has to be disposed in the position on the cylindrical main body 14 where at least a part of a male screw forming the cutting tap section 20 can bite into a sidewall of a closure C when work for forming an opening is started. [0045]

The cutting section 12 includes a plurality of cutting blades 22, 22 disposed separately in the circumferential direction in an annular distal end portion formed at one end of the cylindrical main body 14. As shown in Figure 2, each cutting blade 22 includes a first blade edge 23 and a second blade edge 24. [0046]

The first blade edge 23 is a blade edge that is located on the axial direction distal end side of the cylindrical main body 14 of the cutting blade 22 and cuts a cutting object in the axial direction distal end side direction ofthe cylindrical main body 14 according to rotation ofthe cylindrical main body 14. The first blade edge has a tilt angle Q1 with respect to an axis X of the cylindrical main body 14. The tilt angle Q1 is equivalent to a so-called rake angle. The first blade edge 23 can efficiently cut, with the rake angle of Q1, the cutting object (the sidewall ofthe closure C) in the axial direction. Q1 is set to, for example, approximately 15 degrees.

[0047]

The first blade edge 23 has a tilt angle of Q2 with respect to a plane orthogonal to the axis of the cylindrical main body 14. With the tilt angle Q2, when the cutting section 12 is pressed against the cutting object (the sidewall of the closure C) in the axial direction of the cylindrical main body 14, the first blade edge 23 bites into the cutting object and can efficiently perform cutting. Q2 is set to, for example, approximately 7 degrees.

[0048]

The second blade edge 24 is provided on the outer circumferential surface side of the cylindrical main body 14 to be adjacent to the first blade edge 23. The secondblade edge 24 isablade edge that cuts the closure C, which is the cutting object, outward in the radial direction while advancing in the axial direction of the cylindrical main body 14 according to the rotation of the cylindrical main body 14. As explained below, the second blade edge 24 is a blade edge with which, in opening forming work, when the cutting section 12 is fit in a prepared hole provided by a hole saw, the cutting section 12 cuts the prepared hole outward in the radial direction to expand the diameter of the prepared hole.

[0049] The valve 16 is bent in an L-shape and a valve channel 25, also bent in an L-shape, pierces through and extends on the inside of the valve 16. The valve 16 is a publicly-known on-off valve that can be opened and closed by turning a knob 28, which is coupled to a valve body 26 disposed in the channel, by 90 degrees. A male screw section 30 is formed in the outer circumference of the valve 16 at one end of the channel.

[0050]

In the boring tool in this embodiment, the valve 16 is coupled to the cylindrical main body 14 by screwing the male screw section 30 on one end side into a female screw section 32 formed on the inner circumferential surface on the other end side of the cylindrical main body 14. As a result, the main body channel 18 piercing through the cylindrical main body 14 and extending in the axial direction communicates with the valve channel 25 of the valve 16.

[0051]

Further, in the cylindrical main body 14, a wrench coupling section 34, to which a tool such as a wrench for rotating the cylindrical main body 14 is coupled, is provided. In the boring tool 10 in this embodiment, the wrench coupling section 34 is provided as a nut-like portion, the cross section of which is hexagonal. Therefore, the boring tool 10 in this embodiment is configured to such that the tool such as a wrench can be coupled to the wrench coupling section 34 to rotate the cylindrical main body 14 around the longitudinal direction axis.

[0052] In use, the boring tool 10 in this embodiment is desirably combined with a positioning tool

36, which holds the boring tool 10, and used as a boring device 38 (for example, Figure 5). Therefore, a boring device in the preferred embodiment of the disclosure includes the boring tool 10 and the positioning tool 36.

The configuration of the positioning tool 36 will be explained. Figure 3 is a perspective view of the positioning tool 36 in this embodiment. [0053]

As shown in Figure 3, the positioning tool 36 in this embodiment schematically includes a guide member 40, which is a rectangular tabular member, and a positioning band 42, which is a band like disposing tool, the guide member 40 being incorporated in a part of the positioning band 42. [0054] Figure 4 is a perspective view of the guide member 40 in this embodiment. As shown in

Figure 4, the guide member 40 includes a substantially circular guide opening 44 piercing through the guide member 40 and extending in the thickness direction. A female screw section 46 capable of screwing with the male screw-like cutting tap section 20 provided on the outer circumferential surface of the boring tool 10 is formed on the inner circumferential surface of the guide opening 44. [0055]

Further, an annular groove 48 is formed at the circumferential edge of the guide opening 44 on the rear surface of the guide member 40, that is, a surface opposed to the closure C during the positioning. An O-ring 50 is disposed in this annular groove.

[0056] The positioning band 42 is configured such that both ends of the positioning band 42 is coupled via a bolt clamp 52 and the circumferential length of the positioning band 42 can be changed by adjusting the bolt clamp 52.

[0057]

Figure 5 is a schematic perspective view showing a state in which the boring device 38 in this embodiment is wound and fixed on the outer circumference of the closure C. The positioning band 42 of the positioning tool 36 is the band- like member as explained above and has a shape that can be wound on the outer circumference of the cylindrical closure C set as a boring target. The length of the positioning band 42 is adjusted by operation of the bolt clamp 52 in this wound state. The positioning band 42 is fixed to the closure C. As a result, the guide member 40 incorporated in the positioning band 42 is positioned on the outside of the outer circumferential wall of the closure C (Figure 5).

[0058]

A boring method for boring the closure C using the boring device 38 in this embodiment including the configuration explained above will be explained with reference to Figure 6 to Figure 11. [0059] First, the guide member 40 of the positioning tool 36 is disposed to be opposed to the outer circumferential surface of the closure C set as the boring taiget. Specifically, the positioning band 42, in which the guide member 40 is incorporated, is wound on the sidewall of the closure C, whereby the guide member 40 is disposed in a predetermined position to be opposed to the outer circumferential surface of the closure C. Subsequently, the bolt clamp 52 is operated to reduce the circumferential length of the positioning band 42. The positioning band 42 is tightened and fixed to the closure C

(Figure 6). [0060]

Subsequently, a hole saw 54 is inserted into the guide opening 44 of the guide member 40 and an annular groove (a prepared hole) 56 is formed in the sidewall of the closure C as a prepared hole for the cutting section 12 of the boring tool 10 (Figure 7). The prepared hole 56 is desirably set to a dimensional-shape smaller than the outer diameter dimension of the annular cutting section 12 of the boring tool 10. When the prepared hole 56 is configured in that way, in a boring process explained below, the cutting section 12 bores the sidewall while cutting the sidewall, then a gap between the cutting tap section 20 and the sidewall can be reduced to substantially zero. The prepared hole 56 is formed to a depth position where the prepared hole 56 does not pierce through the sidewall of the closure C (Figure 8).

[0061]

Note that the prepared hole 56 may have a shape other than the annular groove and may be formed as a simple cylindrical recess. The hole saw 54 is capable of performing boring with a smaller force compared with when a general drill is used. The hole saw 54 can be suitably used under a situation in which it is difficult to perform boring with an electric tool as in a manhole.

[0062]

Subsequently, the male screw-like cutting tap section 20 provided in the outer circumference of the cylindrical main body 14 of the boring tool 10 is screwed in the female screw section 46 of the guide opening 44 of the guide member 40. At this time, the cutting blade 22 at the distal end of the cylindrical main body 14 of the boring tool 10 is housed in the annular prepared hole 56 formed in advance. [0063]

Note that, although not shown in Figure 9 to Figure 11, the valve 16 set in a closed state is coupled to the boring tool 10. Therefore, the main body channel 18 of the cylindrical main body 14 is closed by the valve 16. [0064]

Further, the cylindrical main body 14 of the boring tool 10 is rotated to move the boring tool 10 from the guide member 40 toward the outer circumferential surface of the closure C. A method of rotating the cylindrical main body 14 may be any method. Flow ever, in this embodiment, as shown in Figure 5, a wrench W is coupled to the nut-like wrench coupling section 34 provided in the cylindrical main body 14 (Figure 5). The cylindrical main body 14 is rotated in the guide opening 44 by turning the wrench W.

[0065]

The female screw section 46 is formed on the inner circumferential surface of the guide opening 44. The male screw-like cutting tap section 20 formed on the outer circumferential surface of the cylindrical main body is screwed in the female screw section 46. Therefore, the cylindrical main body 14 of the boring tool 10 rotates in the guide opening 44 of the guide member 40 to thereby obtain propulsion to the axial direction and move in the closure C direction (Figure 9). According to this movement, the cutting blade 22 of the cutting section 12 housed in the prepared hole 56 cuts the sidewall of the closure C located on the bottom surface and the side surface of the prepared hole 56.

[0066] As a result, the cutting section 12 of the boring tool 10 annularly cuts the sidewall of the closure C. The boring tool 10 is pressed against the sidewall of the closure C by the screwing of the cutting tap section 20 and the female screw section 46 to cut the sidewall. Therefore, an operator does not need to apply a force to the boring tool 10 in the axial direction in order to perform boring and can perform boring only by rotating the boring tool 10.

[0067]

At this time, the male screw-like cutting tap section 20 provided on the outer circumferential surface of the cylindrical main body 14 advances in the sidewall of the closure C while cutting a female screw on the wall surface of the closure C. At this time, the outer circumferential surface of the cylindrical main body 14, in which the cutting tap section 20 is formed, is in contact with the sidewall of the closure C in an airtight state.

[0068]

Further, the cylindrical main body 14 of the boring tool 10 is continued to be rotated and the cutting section 12 of the boring tool 10 is caused to pierce through the sidewall ofthe closure C, whereby a through-hole 58 (an opening) is formed on the sidewall ofthe closure C (Figure 10). As explained above, the airtight state is maintained between the outer circumferential surface ofthe cylindrical main body 14, in which the cutting tap section 20 is formed, and the sidewall of the closure C. Therefore, even when the cutting section 12 at the distal end of the cylindrical main body 14 pierces through the sidewall of the closure C and intrudes into the internal space of the closure C, high-pressure air inside the closure C is suppressed from leaking from between the outer circumferential surface of the cylindrical main body 14 and the wall of the closure C. [0069]

Note that, in this specification, the airtight state does not always mean an absolute or complete airtight state and includes a state in which a small amount of air leaks from the closure in a degree enough for maintaining the internal pressure of the closure C that can suppress intrusion of water into the inside of the closure.

[0070]

After the sidewall is pierced through, the cylindrical main body 14 of the boring tool 10 is reversely rotated. Apart C ' of the sidewall of the closure C cut off from the closure C and housed in the distal end of the cylindrical main body 14 of the boring tool 10 comes into contact with the inner wall ofthe closure C and is discharged from the cylindrical main body 14 (Figure 11). Consequently, the filling ofthe resin and the discharge ofthe air canbe prevented from being hindered. Subsequently, the boring tool 10 is rotated again to be closely attached to the positioning tool to end the boring work. [0071]

After the boring work ends, in a state in which the boring tool 10 of the boring device 38 is caused to pierce through the sidewall of the closure C, filling work for injecting resin or the like into the closure C through the main body channel 18 and the valve channel 25 of the boring tool 10 is performed.

[0072]

A method of filling resin into the closure C will be explained. First, a filling method in a first embodiment will be explained. Figure 12 is a diagram that illustrates a configuration for implementing the filling method in the first embodiment. Figure 13 is a flowchart ofthe filling method in the first embodiment.

[0073]

In the resin injection, a press-in port 60 on a side where resin is injected and a relief port 62 for emitting gas in the closure C in pressing-in are provided in the closure C. The press-in port 60 is desirably provided on the lower surface on one end side of the closure C. The reliefport 62 is desirably provided on the upper surface on the other end side of the closure C.

[0074]

In the filling method in the first embodiment, the press-in port 60 and the relief port 62 are formed by the boring tool 10 in the embodiment explained above. The valve 16 that can be manually opened and closed explained above is incorporated in the boring tool 10 of the press-in port 60 and the boring tool 10 on the relief port 62 side. Further, an automatic relief valve 66 that automatically opens at approximately pressure Psys via a transparent tube 64 is attached to the boring tool on the relief port 62 side.

[0075] The pressure Psys is pressure in the closure C and a cable, that is, pressure in a cable system raised by pressurized air or the like. In general, the pressure Psys is approximately 63.7 kPa. Withstand pressure of the closure C is represented as Pmax.

[0076]

In this example, the automatic relief valve 66 is set to emit air at pressure near the pressure Psys. The automatic relief valve 66 desirably automatically opens at pressure slightly higher than the pressure Psys. The automatic relief valve 66 may automatically open at pressure slightly lower than the pressure Psys.

[0077]

As shown in Figure 12, a resin supply device 68 is coupled to the valve on the press-in port 60 side (the valve of the boring tool 10) via a transparent tube 70. In the resin supply device 68, a container 74, which stores liquid resin to be injected and to which one end of the transparent tube 70 is connected, is disposed in a pressure container 72. The resin supply device 68 is configured such that the inside of the pressure container 72 is pressurized by compressed air supplied from a compressed air supply pipe 76, whereby the liquid resin in the container 74 is supplied to the press-in port 60 of the closure C through the transparent tube 70. Pressure at which the resin is pressure-fed is the airpressure of the compressed air supplied into the pressure container 72.

Note that another method, for example, a pump may be used for the supply of the liquid resin.

[0078]

As the resin to be injected, resin having fluidity that hardens after injection such as polyurethane rein, silicon resin, or epoxy resin of a two-part curing type can be used. [0079]

When the filling work is started, first, the valve on the press-in port 60 side (the valve of the boring tool) and the valve on the relief port 62 side (the valve of the boring tool) are closed (SI).

Subsequently, compressed air is supplied into the pressure container 72 and the pressure in the pressure container is adjusted to be Psys or more and Pmax or less using a not-shown regulator or the like. Subsequently, in a state in which the valve on the relief port 62 side is opened, the valve on the press-in port 60 side is opened to pressure-feed the resin from the pressure container 72 into the closure C at pressure P equal to or higher than Psys and equal to or lower than Pmax through the transparent tube 70 (S2).

[0080]

The closure C is filled by the pressure-fed resin. The air in the closure C is emitted from the relief port 62. When it is visually confirmed that the resin intrudes into the transparent tube 64 connected to the relief port 62, it is determined that the closure C is almost filled (fully filled) by the resin. The valve on the relief port 62 side is closed (S3).

[0081]

According to necessity, in a state in which the valve on the relief port 62 side is closed, the resin is continued to be pressure-fed from the pressure container 72 into the closure C for a fixed time at pressure equal to or higher than Psys and equal to or lower than Pmax to be filled in the closure C. Finally, the valve on the press-in port 60 side is closed (S4).

[0082]

Note that a configuration may be adopted in which a pressure gauge that measures the pressure of the inside of the closure C is set and the valve on the press-in port 60 side is closed immediately before or when the pressure inside the closure reaches the pressure Pmax.

With such a configuration, it is possible to press in the resin in a state in which the resin is pressurized to the maximum. It is possible to sufficiently spread the resin in the closure while avoiding breakage of the closure.

[0083] A method of filling the resin while measuring the weight of the pressure container and closing the valve on the press-in port side when a decrease in the weight of the pressure container stops may be adopted.

[0084] Note that, when it is unnecessary to actively increase the internal pressure of the closure C, a method of closing the valve on the press-in port 60 side before closing the valve on the relief port 62 side may be adopted.

[0085]

By setting the length of the transparent tube 64 sufficiently large, the resin is prevented from reaching the automatic relief valve 66 during the filling work. It is possible to detach the automatic relief valve 66 after the filling work and reuse the automatic relief valve 66.

[0086]

With such a filling method, a pressure difference is maintained between the internal pressure of the closure C and the resin pressure-feeding pressure by the automatic relief valve 66 that operates at pressure near Psys. It is possible to easily fill the resin in the closure C. Since the pressure in the pressure container is adjusted to Pmax or less. Therefore, the internal pressure of the closure C does not exceed Pmax. As a result, the closure is not broken.

[0087]

As a modification of the filling method in the first embodiment, a method shown in a flowchart of Figure 14 may be adopted. In this modification, working pressure of the automatic relief valve 66 is set to Psys or more and Pmax or less, the pressure in the pressure container 72 is set to Pmax or more, and the resin is pressure-fed at the pressure P higher than Pmax.

In this method, first, the valve of the press-in port 60 and the automatic relief valve 66 are closed (S5). Subsequently, the valve of the press-in port 60 is opened to pressure-feed the resin at the pressure P higher than Pmax (S6). After full filling is confirmed, first, the valve of the press -in port is closed (S7). Thereafter, the valve of the relief port is closed (S8).

With this method, the filling work is completed in a short time because the resin can be pressure-fed (injected) at pressure higher than Pmax.

[0088]

A filling method in a second embodiment will be explained. Figure 15 is a diagram that illustrates a configuration for implementing the filling method in the second embodiment. Figure 16 is a flowchart that illustrates the filling method in the second embodiment.

[0089]

A basic configuration of a device used in the second embodiment of the filling work is the same as the basic configuration of the device used in the first embodiment. The device used in the second embodiment of the filling work and the device used in the first embodiment are different in that an automatic relief valve 80 is connected to a pressure container via an on-off valve 78. The automatic relief valve 80 connected to the pressure container 72 is set to operate at Pmax. In this method, compressed air having pressure higher than Pmax is supplied into the pressure container 72, whereby the pressure in the pressure container 72, that is, the pressure of resin to be pressure-fed is set to pressure higher than Pmax.

[0090] In the filling work in the second embodiment, as in the first embodiment, first, when the filling work is started, first, the valve on the press-in port 60 side (the valve of the boring tool) and the valve on the relief port 62 side (the valve of the boring tool) are set in a closed state (S9). Subsequently, in a state in which the on-off valve 78 is closed, compressed air having pressure higher than Pmax is supplied into the pressure container 72. Subsequently, the valve of the relief port 62 is opened, the valve on the press-in port 60 side is opened, and the resin is filled in the closure C at the pressure P higher than Pmax (for example, approximately three times of Pmax) (S10). Pressure-feeding pressure of the resin is higher than Pmax. However, the internal pressure of the closure C is maintained a Psys or less by the action of the automatic relief valve 66 on the relief port 62 side. [0091]

The closure C is filled with the pressure-fed rein. The air in the closure C is emitted from the relief port 62. When it is visually confirmed that the resin intrudes into the transparent tube 64 connected to the relief port 62, it is determined that the closure C is almost filled (fully filled) by the resin. The valve 78 is opened. [0092]

As a result, the internal pressure of the pressure container 72 drops to Pmax or less with the action of the automatic relief valve 80 that operates at Pmax. The pressure applied to the resin in the pressure container 72 also drops to Pmax or less. When the pressure in the pressure container 72 drops to Pmax, which is safe pressure, or less, the resin supply pressure P to the closure C also drops to Pmax or less.

[0093] By maintaining this state according to necessity, the supply of the resin is continued from the pressure container 72 at pressure specified in the automatic relief valve 80 equal to or lower than the pressure Pmax. The resin filling is facilitated on the inside of the closure C. The valve on the relief port 62 side is closed at a point in time when the filling is completed (S12). [0094]

In order to prevent the internal pressure of the closure C from exceeding Pmax from when the resin overflows from the relief port 62 until the internal pressure of the pressure container 72 drops to Pmax or less with the action of the automatic relief valve 80, it is desirable to align a cross section of a channel of the resin from the relief port 62 and a cross section of a channel of the resin of the press-in port 60.

[0095]

However, actually, a pressure loss occurs between the pressure container 72 and the closure C. Therefore, the channel of the resin from the relief port 62 may be sometimes narrower than the channel of the resin on the press-in port 60 side. [0096]

With such a method, the resin can be pressure- fed at pressure higher than Pmax. Therefore, compared with the first method, the filling is completed in a short time. Pressure of Psys or more and Pmax or less can be retained after the full filling. Therefore, the resin can be filled in every corner of the closure. As a result, the second method is particularly suitable when resin having high reaction speed that needs to be filed in a short time or a resin having low fluidity such as high- viscosity resin is pressure-fed. [0097]

Various changes and modifications are possible within the range of the technical idea described in the patent claims without being limited by the embodiments of the disclosure.

[0098] In the embodiments, the guide member is disposed with respect to the closure by the positioning band. However, the guide member may be disposed with respect to the surface of the closure using a method or means other than the positioning band, for example, a self-tapping screw or an adhesive.

[0099] The closure includes a mechanical closure, a housing of which is formed mainly of plastic and a lead pipe, a housing of which is made of lead. However, aspects of the disclosure can be applied to both the mechanical closure and the lead pipe.

List of Reference Numerals

[0100] C: closure

W: wrench 10: boring tool 12: cutting section 14: cylindrical main body 16: valve

18: main body channel 20: cutting tap section

22: cutting blade 25: valve channel 26: valve body 28: knob

30: male screw section

32: female screw section 34: wrench coupling section 36: positioning tool 38: boring device

40: guide member 42: positioning band 44: guide opening 46: female screw section 50: 0-ring

52: bolt clamp