KR101820450B1 - Pipe insulation apparatus with vibration prevention function - Google Patents

Abstract

The present invention relates to a pipe insulation apparatus with a vibration prevention function capable of reducing vibration and noise generated in a pipe. The pipe insulation apparatus of the present invention comprises: semi-cylindrical first and second insulation materials surrounding one side and the other side in a width direction of the pipe; first and second finishing covers respectively covering outer side surfaces of the first insulation material and the second insulation material; first and second protection sheets covering an area of surfaces of the first insulation material and the second insulation material that is not covered by the first finishing cover or the second finishing cover; a fastening means coupling the first finishing cover and the second finishing cover; and a vibration prevention means having an outer pipe extending from an inner side surfaces of the first finishing cover and the second finishing cover to a center of the pipe, an inner pipe having one end in a longitudinal direction inserted into the outer pipe and the other end in the longitudinal direction mounted on the first protection sheet and the second protection sheet, and a coil spring-shaped elastic body surrounding outer peripheral surfaces of the outer pipe and the inner pipe and having both ends in the longitudinal direction mounted on the first finishing cover and the first protection sheet or the second finishing cover and the second protection sheet.

Description

TECHNICAL FIELD [0001] The present invention relates to an insulation device for a pipe having a dustproof function,

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a heat insulation device for a pipe installed to surround an outer surface of a pipe, and more particularly to a heat insulation device for a pipe having a dustproof function so as to reduce vibration and noise generated in the pipe.

Generally, various kinds of piping facilities are installed in buildings such as office buildings, industrial buildings and apartments, and these piping facilities are installed with insulation covers for the purpose of maintaining the insulation and cooling or additionally extending the life of the piping facilities and designing the exterior These insulating covers are mainly used in valves, T-tubes, elbows, and straight pipes in piping systems.

In particular, power plants (nuclear power plants, thermal power plants, etc.) and petrochemical plants produce high-temperature, high-pressure steam produced by the boiler to provide rotational power to the turbine and ultimately produce electrical energy. Since the piping thickness is reduced due to fluid friction and cavitation in the piping during transport, there is a risk of causing safety accidents in the system during normal operation. During the maintenance, the integrity of the piping is checked by checking the condition of the piping being depressed (the wall of the piping is thinned due to causes such as corrosion).

In case of using the existing insulation material when performing the thinning inspection, the metallic cover of the finished material and the insulation material are sequentially removed from the outside of the pipe, and then the thinning inspection is carried out. After the thinning inspection is completed, And finished with a cover finish.

This type of thermal insulation construction method causes an enormous waste of materials due to the disposal amount of the thermal insulation material and the finishing cover which are dismantled every year. Especially, in the case of the elbow or T-joint part, In addition, thermal erosion due to thermal notch may cause thermal stress to increase and the thinning phenomenon may progress significantly, which may shorten the life of the entire piping. .

In order to solve the above-described problems, there has been proposed a heat insulating apparatus for piping that is easy to attach and detach, minimizes the occurrence of heat insulating gaps, and can greatly simplify the pipe thinning inspection and the construction work of the heat insulating material. Such a heat insulation device for piping has an advantage of improving the ease of construction and heat insulation, but has a disadvantage in that vibration and noise generated when a high-pressure fluid flows inside the piping are spread evenly to the outside.

Of course, when the heat insulating material is installed to wrap the pipe directly, the heat insulating material can attenuate vibration and noise generated in the pipe to some extent. However, if the heat insulating material contacts the pipe directly, the life of the heat insulating material is shortened, It is not possible to maintain it.

KR 10-1184392 B1

Disclosure of Invention Technical Problem [8] Accordingly, the present invention has been made in order to solve the above-mentioned problems, and it is an object of the present invention to provide an air conditioner capable of damping vibration and noise generated in a pipe, The present invention has been made in view of the above problems.

According to an aspect of the present invention, there is provided an insulation device for a pipe, comprising: a semi-cylindrical heat insulating material and a second heat insulating material surrounding one side and the other side in a width direction of the pipe; A first finishing cover and a second finishing cover covering the outer surfaces of the first heat insulator and the second heat insulator; A first protective sheet and a second protective sheet covering a portion of the surface of the first heat insulating material and the second heat insulating material that is not covered by the first finish cover or the second finish cover; Fastening means for engaging the first and second closing covers; A pair of first fastening sockets into which both ends of the first finishing cover in the width direction are respectively inserted; A pair of second fastening sockets into which both ends of the second finishing cover in the width direction are respectively inserted; A fastening packing in which the first fastening socket and the second fastening socket are inserted into a face facing each other; The first and second fastening sockets are inserted into the first and second fastening holes so as to penetrate through one side in the width direction of the first protective sheet and then pass through the first fastening socket of the first fastening socket, And a plurality of fastening rivets which are fastened to the fastening sockets so as to penetrate through the portion where the second finishing cover is inserted, wherein both sides of the first and second protective sheets in the width direction are located at positions where the fastening rivet passes And a fastening washer in which the head of the fastening rivet is seated, wherein the fastening washer is folded to be overlapped in two layers, and is inserted into a folded portion of both the widthwise sides of the first and second protective sheets.

Wherein the heat insulating device for piping comprises at least one first connection sheet in which one end in the longitudinal direction is coupled to the first protective sheet and the other end in the longitudinal direction passes through the first heat insulating material and is coupled to the first finish cover, And at least one second connection sheet coupled to the second protective sheet and having a longitudinally opposite end penetrating the second insulation to be coupled to the second finishing cover.
Wherein the heat insulating device for pipes comprises an outer tube extending from an inner side of the first closed cover and a second closed cover toward a center of the pipe, A first protective sheet and a second protective sheet, and a coil spring shape which surrounds the outer circumferential surface of the outer tube and the inner tube, wherein both ends in the longitudinal direction are seated on the first finishing cover and the first protective sheet, And an anti-vibration means composed of an elastic body that is seated on the second cover and the second protective sheet.

The first fastening socket further includes an extension piece covering an outer surface of the second fastening socket.

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Wherein the heat insulating device for pipes comprises a pair of connection sockets formed in a ring shape and having both longitudinal ends of the first finishing cover and the second finishing cover inserted therein; A ring-shaped connecting packing inserted between two mutually opposing connecting sockets when the two finishing covers are arranged in a line along the longitudinal direction; A connector ring mounted to cover two mutually opposing connection sockets to integrally join two finishing covers arranged in a row and having a connector packing on the inner side facing the connection socket; And a plurality of connecting rivets which are coupled to penetrate the one longitudinal side of the first protective sheet or one longitudinal side of the second protective sheet, ; ≪ / RTI >

Wherein both sides of the first protective sheet and the second protective sheet in the longitudinal direction are folded so that a portion through which the connecting rivet penetrates is overlapped by two layers and the folded portion of the first protective sheet and the second protective sheet, And a connecting washer on which the head of the connecting rivet is seated.

The first cover and the second cover may be made of a metal, and the first and second protective sheets may be fabric materials.

The use of the insulation device for piping according to the present invention has the advantage that the vibration and noise generated in the piping can be attenuated, the position of the insulation can be stably fixed, and the heat insulation property is remarkably improved.

1 is an exploded cross-sectional view of an adiabatic device for piping according to the present invention.
Fig. 2 and Fig. 3 show the state of use of the fastening means.
4 is a cross-sectional view of an adiabatic device for piping according to the present invention.
5 is an enlarged cross-sectional view showing a combined structure of the first finishing cover and the second finishing cover.
Figure 6 shows a configuration in which two finish covers are arranged in a row in the longitudinal direction.
Figs. 7 and 8 are sectional views showing a structure in which two finish covers are combined. Fig.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of an insulation device for piping according to the present invention will be described in detail with reference to the accompanying drawings.

Fig. 1 is a disassembled cross-sectional view of a heat insulating apparatus for piping according to the present invention, Figs. 2 and 3 are a state of use of fastening means, and Fig. 4 is a sectional view of a heat insulating apparatus for piping according to the present invention.

The insulation device for piping according to the present invention is installed so as to surround the piping 10 through which high-temperature, high-pressure steam or hot water flows, thereby improving the heat insulation of the piping 10 and preventing the piping 10 from being damaged by an external impact And is capable of attenuating vibration and noise generated in the piping (10).

That is, the heat insulating device for piping according to the present invention includes a semi-cylindrical first heat insulating material 110 and a second heat insulating material 120 that surround one side and the other side in the width direction of the pipe 10, A first finishing cover 210 and a second finishing cover 220 covering the outer surfaces of the first and second heat insulating materials 120 and 120 and the first and second finishing covers 210 and 220, A first protective sheet 310 and a second protective sheet 320 covering a portion not covered by the cover 210 or the second finishing cover 220 and a second protective sheet 310 covering the first finishing cover 210 and the second finishing cover 220. [ (600) for absorbing the vibration generated in the pipe (10).

When the first and second finishing covers 210 and 220 are coupled to each other, the first finishing cover 210 and the second finishing cover 220 are made of a metal such as an aluminum alloy or the like so as to have rigidity against external impact. . The first and second closing covers 210 and 220 are detachably coupled to each other by a plurality of fastening means 500 provided on both sides in the width direction (left and right in FIG. 1). At this time, the fastening means 500 includes a fastening hook 510 fixedly coupled to the second fastening cover 220, a rotation piece 520 coupled to the first fastening cover 210 in a rotatable manner, And a fastening link 530 which is coupled to the rotating piece 520 and bent at one end to be hooked on the fastening hook 510. The fastening means 500 is a conventional insulator for piping 10-1184392), the detailed description of the structure and operation principle of the fastening means 500 will be omitted.

The first protective sheet 310 and the second protective sheet 320 are formed so that the surfaces of the first and second heat insulating materials 110 and 120 are not exposed to the outside, And is made of a nonflammable fabric such as ceramic fiber or the like so as not to be damaged by heat generated in the piping 10. The first protective sheet 310 and the second protective sheet 320 are fabricated to have a flexible characteristic so that even if the surface of the pipe 10 is irregular or some protruding portions are present, It is possible to surround them. The first protective sheet 310 and the second protective sheet 320 may include a plurality of sus wires in order to improve durability.

The first heat insulating material 110 and the second heat insulating material 120 are components for cutting off the heat radiated through the surface of the pipe 10. When the both sides of the pipe 10 are joined to each other in the width direction, Thereby forming a single hollow tube shape surrounding the entire side surface. The heat insulating material 100 may be made of various kinds of heat insulating materials such as styrofoam and glass fiber as long as it can block heat emitted through the surface of the pipe 10.

The vibration damping means 600 is a component for damping the vibration in the middle so that no vibration generated in the piping 10 is transmitted to the finish cover 200. The first and second finishing covers 210, 2 an outer tube 610 extending from the inner side of the finishing cover 220 toward the center of the tube 10 and one end in the longitudinal direction inserted into the outer tube 610, The inner tube 620 is seated on the seat 310 and the second protective sheet 320. The outer tube 610 and the inner tube 620 are wrapped around the outer surface of the outer tube 610 and the inner tube 620, And an elastic body 630 that is seated on the first cover sheet 210 and the first protective sheet 310 or seated on the second cover sheet 220 and the second protective sheet 320. The outer tube 610 is coupled to the inner surface of the finishing cover 200 (more specifically, the surface that contacts the heat insulating material 100) on one side in the longitudinal direction, and the other side of the outer tube 610 is spaced apart from the protective sheet 300 Length. The inner tube 620 is formed such that one side of the inner tube 620 is coupled to a surface of the protective sheet 300 surrounding the pipe 10 and the other side of the inner tube 620 is spaced apart from the finishing cover 200. Accordingly, the inner tube 620 can be moved to a certain level in the longitudinal direction while being inserted into the outer tube 610.

4, the inner tube 620 reciprocates in the longitudinal direction (up-and-down direction in FIG. 4), so that the outer tube 610 and the outer tube 610 The elastic body 630 surrounding the inner tube 620 absorbs vibration of the pipe 10 while repeatedly performing compression and restoration. That is, even if the piping 10 vibrates, the vibration of the pipe 10 is not transmitted to the finish cover 200 as it is, but is mostly absorbed by the elastic body 630 of the dustproof means 600, It is possible to effectively prevent a phenomenon in which a vibration occurs.

The vibration of the pipe 10 is absorbed by the elastic body 630 so that when the elastic body 630 is formed in a coil spring shape and installed between the finish cover 200 and the protective sheet 300, The vibration of the pipe 10 may not be transmitted to the finishing cover 200 even if the inner pipe 610 and the inner pipe 620 are omitted. However, if the dust-proofing means 600 is composed only of the coil-spring-shaped elastic body 630, the elastic body 630 may be inclined at the time of vibration of the pipe 10, and vibration may not be normally absorbed.

Therefore, as shown in the present embodiment, it is preferable that the anti-vibration means 600 is configured such that one elastic body 630 spirally surrounds the outer tube 610 and the inner tube 620 connected by a double tube structure . If the elastic body 630 is configured to spirally enclose the outer tube 610 and the inner tube 620 as long as the outer tube 610 is not separated from the finish cover 200, The longitudinal direction of the pipe 10 is kept constant so as to face the central axis of the pipe 10, so that the vibration of the pipe 10 can be effectively damped.

At this time, it is preferable that the outer tube 610 is made of stainless steel so as to have high abrasion resistance while being firmly connected to the first finishing cover 210 made of a metal. Also, the inner tube 620 is preferably made of stainless steel so as not to be easily worn or deformed even if it rubs with the outer tube 610 several times.

In order to keep the heat insulating material 100 positioned between the finishing cover 200 and the protective sheet 300 from being tilted or shifted to one side, that is, The space between the finishing cover 200 and the protective sheet 300 may have a cell structure. For example, as shown in FIG. 1, one end in the longitudinal direction is coupled to the first protective sheet 310, and the other end in the longitudinal direction passes through the first heat insulating material 110, One end in the longitudinal direction is coupled to the second protective sheet 320 and the other end in the longitudinal direction passes through the second heat insulating material 120 to be connected to the second closing cover 220 One or more second connection sheets 420 may be additionally provided.

When two first connection sheets 410 and two second connection sheets 420 are provided as shown in this embodiment, a space where the first insulation member 110 is located and a second insulation member 120 The first and second heat insulating materials 110 and 120 are prevented from being shifted to one side or moving abnormally. Since the first insulation sheet 110 and the second insulation sheet 120 are divided into three pieces when the first connection sheet 410 and the second connection sheet 420 are provided as in the present embodiment, If any part of the first insulating material 110 or the second insulating material 120 is broken or damaged, only the corresponding part can be partially replaced, thereby reducing the maintenance cost.

5 is an enlarged cross-sectional view showing a combined structure of the first finishing cover 210 and the second finishing cover 220. As shown in Fig.

Since the first and second finishing covers 210 and 220 are made of a metal plate so that both ends of the first finishing cover 210 and the second finishing cover 220 in the width direction The connection between the first and second closing covers 210 and 220 may not be completely sealed. If the first and second finishing covers 210 and 220 are not completely sealed, the heat of the piping 10 is leaked and the noise generated from the piping 10 is leaked to the outside A problem arises.

Therefore, in order to completely seal between the first and second finishing covers 210 and 220, both ends of the first finishing cover 210 in the width direction A pair of first fastening sockets 710 into which the first fastening sockets 710 are inserted and a pair of second fastening sockets 710 through which both ends of the second finishing cover 220 in the width direction And a second fastening socket 720. The first fastening socket 710 includes a fastening packing 740 inserted into a face of the first fastening socket 710 and the second fastening socket 720 facing each other, And a fastening rivet 730 fastened to the second fastening socket 720 so as to pass through the second fastening cover 220 where the second fastening cover 220 is inserted.

When the widthwise ends of the first and second finishing covers 210 and 220 are inserted into the first and second fastening sockets 710 and 720, The contact area between the first fastening sockets 710 increases and the contact area between the second closing cover 220 and the second fastening sockets 720 increases so that the distance between the first fastening cover 210 and the first fastening socket 710 increases, A phenomenon in which heat or noise flows out between the first closing cover 220 and the second closing socket 220 or between the second closing cover 220 and the second closing socket 720 is remarkably reduced. The first fastening sockets 710 and the second fastening sockets 720 are filled with a fastening packing 740 made of silicon or the like so long as the fastening packing 740 is not torn or broken, So that no heat or noise is leaked between the fastening socket 710 and the second fastening socket 720. 5, the first closing cover 210 and the second closing cover 220 are connected to each other through the first locking socket 710, the second locking socket 720, and the locking packing 740 as a medium The inside of the finish cover 200 is completely isolated from the outside, and the effect of improving the heat insulation and the sound insulation remarkably can be obtained.

The first fastening sockets 710 may include an extension piece 712 covering an outer surface of the second fastening sockets 720 so that no foreign matter such as rainwater or oil may come into contact with the fastening packing 740, May be additionally provided.

The protective sheet 300 is not made of metal but is made of a soft fabric. Therefore, when the protective sheet 300 is directly coupled to the finish cover 200 made of metal, the protective sheet 300 300 may easily fall off from the finish cover 200.

The heat insulating device for piping according to the present invention is provided with the first protective sheet 310 and the second protective sheet 320 so that the widthwise both sides of the protective sheet 300 can be more firmly coupled to the finish cover 200. [ The first and second fastening sockets 710 and 720 are fastened together by the fastening rivet 730. The first fastening sockets 710 and the second fastening sockets 720 are fastened together. A fixing wire 330 inserted into a folded portion of the first protective sheet 310 and the second protective sheet 320 in a widthwise direction of the first protective sheet 310 and the second protective sheet 320, A washer 750 is additionally provided.

As shown in FIG. 5, the fixing wire 330 is located at a position outside the region where the locking washers 750 are seated. The first and second protective sheets 310 and 320 are not easily separated from the fastening sockets 710 and 710 and the fastening washer 750, So that it is firmly coupled to the second closing cover 220.

Fig. 6 shows a configuration in which two finishing covers 200 are arranged in a line in the longitudinal direction, and Fig. 7 and Fig. 8 are sectional views showing a structure in which two finishing covers 200 are combined.

6, the heat insulating device for piping according to the present invention is formed in a ring shape so as to be connected in a row along the longitudinal direction as shown in FIG. 6, so that the longitudinal direction of the first and second closing covers 210, A pair of connection sockets 810 into which both ends are inserted, and a ring-shaped connection packing 810 inserted between two connection sockets 810 facing each other when the two finishing covers 200 are arranged in a row along the longitudinal direction, (830) and two closing covers (200) arranged in a line so as to cover two mutually opposing connection sockets (810), integrally connecting the connector cover (200) and the connector packing And a second protection sheet (320) extending in a longitudinal direction of the first protection sheet (310) or in a longitudinal direction of the second protection sheet (320). The connector ring (910) Through which the finishing cover 210 or the second finishing cover 220 is inserted, Which it may be provided with a plurality of connection rivets 820.

The connector ring 910 is separated into semicircular shapes and is coupled by a separate connector clip 920. Such a connector ring 910 is widely used in various fields as well as the technical field of the present invention, A detailed description of the process in which the connector ring 910 is separated into two semicircles or combined to form one ring will be omitted. Further, the connector clip 920 is substantially the same as the fastening means 500 shown in FIGS. 1 to 3, so that detailed description of the structure and operation principle of the connector clip 920 will be omitted.

As described above, when the connecting sockets 810 are respectively provided at both ends of the finishing cover 200 in the longitudinal direction, the two finishing covers 200 arranged in a line by using the connector ring 910 can be firmly coupled And there is an advantage in that the phenomenon that heat or noise flows out between the two finishing covers 200 can be surely prevented.

In order to more reliably prevent heat and noise from flowing between the connection socket 810 and the connector packing 912, a protruding end protruding toward the connector packing 912 is formed at the widthwise edge of the connection socket 810, (812) may be provided.

The first protective sheet 310 and the second protective sheet 300 are formed so that the both sides of the protective sheet 300 in the longitudinal direction (more specifically, the side corresponding to the connection socket 810) The first and second protective sheets 320 and 320 may be folded so that two portions of the second protective sheet 320 on which the connection rivet 820 passes are overlapped with each other, A fixing ring 340 inserted into the folded portion of both sides and a connecting washer 840 on which the head of the connecting rivet 820 is seated can be additionally provided.

The fixing ring 340 is located at a position out of the area where the connecting washer 840 is seated and the first and second protective sheets 310 and 310 are not damaged or detached, It is advantageous that both longitudinal sides of the first cover 320 and the second cover 300 are not separated from the first cover 210 and the second cover 220. The structure in which both longitudinal sides of the protective sheet 300 are coupled to both sides in the longitudinal direction of the finishing cover 200 is a structure in which both sides in the width direction of the protective sheet 300 are coupled to both sides in the width direction of the finishing cover 200 (See FIG. 5), the connection washer 840, the protective sheet 300, the connection socket 810, and the finish cover 200 are integrally joined by the connection rivet 820 A detailed description thereof will be omitted.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the scope of the present invention is not limited to the disclosed exemplary embodiments. It will also be appreciated that many modifications and variations will be apparent to those skilled in the art without departing from the scope of the invention.

10: Piping 100: Insulation
110: first insulating material 120: second insulating material
200: Finishing cover 210: First finishing cover
220: second finishing cover 300: protective sheet
310: first protective sheet 320: second protective sheet
330: fixed wire 340: fixed ring
410: first connecting sheet 420: second connecting sheet
500: fastening means 510: fastening hook
520: rotating piece 530: fastening link
600: anti-vibration means 610: outer tube
620: Inner tube 630: Elastomer
710: first fastening socket 720: second fastening socket
730: fastening rivet 740: fastening packing
750: fastening washer 810: connection socket
820: Connection Rivet 830: Connection Packing
840: Connecting washer 910: Connector ring
912: Connector packing 920: Connector clip

Claims (8)

A semi-cylindrical heat insulating material and a second heat insulating material surrounding one side and the other side in the width direction of the pipe;
A first finishing cover and a second finishing cover covering the outer surfaces of the first heat insulator and the second heat insulator;
A first protective sheet and a second protective sheet covering a portion of the surface of the first heat insulating material and the second heat insulating material that is not covered by the first finish cover or the second finish cover;
Fastening means for engaging the first and second closing covers;
A pair of first fastening sockets into which both ends of the first finishing cover in the width direction are respectively inserted;
A pair of second fastening sockets into which both ends of the second finishing cover in the width direction are respectively inserted;
A fastening packing in which the first fastening socket and the second fastening socket are inserted into a face facing each other; And
The first and second fastening sockets are inserted into the first and second fastening holes so as to penetrate through one side in the width direction of the first protective sheet and then pass through the first fastening socket of the first fastening socket, A plurality of fastening rivets fastened to the fastening sockets so as to penetrate a portion where the second finishing cover is inserted; / RTI >
Both sides of the first protective sheet and the second protective sheet in the width direction are folded so that a portion through which the fixing rivet passes is overlapped in two layers,
Further comprising: a fixing wire inserted into a folded portion of both the widthwise sides of the first and second protective sheets; and a fastening washer on which the head of the fastening rivet is seated. The method according to claim 1,
One or more first connection sheets, one end of which is longitudinally coupled to the first protective sheet and the other end of which is longitudinally penetrated through the first heat insulating member and joined to the first finishing cover,
Further comprising at least one second connection sheet having one end in the longitudinal direction coupled to the second protective sheet and the other end in the longitudinal direction passing through the second insulation member and coupled to the second finishing cover. The method according to claim 1,
An outer tube extending from an inner surface of the first and second closed covers toward a center of the pipe; and a second tube having one end in the longitudinal direction inserted into the outer tube and the other end in the longitudinal direction, A coil spring shape which surrounds the outer circumferential surface of the outer tube and the inner tube, both ends in the longitudinal direction are seated on the first finishing cover and the first protective sheet, or the second finishing cover and the second protection Further comprising an anti-vibration means composed of an elastic body that is seated on the seat. delete The method according to claim 1,
Wherein the first fastening socket further comprises an extension piece covering an outer surface of the second fastening socket. The method according to claim 1,
A pair of connection sockets formed in a ring shape and having both longitudinal ends of the first finishing cover and the second finishing cover inserted therein;
A ring-shaped connecting packing inserted between two mutually opposing connecting sockets when the two finishing covers are arranged in a line along the longitudinal direction;
A connector ring mounted to cover two mutually opposing connection sockets to integrally join two finishing covers arranged in a row and having a connector packing on the inner side facing the connection socket; And
And a plurality of connecting rivets which are coupled to penetrate the one longitudinal side of the first protective sheet or one longitudinal side of the second protective sheet, ;
Further comprising: a heat insulating member for heat insulating the pipe. The method of claim 6,
Both sides of the first protective sheet and the second protective sheet in the longitudinal direction are folded so that a portion through which the connecting rivet passes is overlapped in two layers,
Further comprising: a fixing ring inserted into a folded portion of the first and second protective sheets in the lengthwise direction of the first and second protective sheets; and a connection washer on which the head of the connection rivet is seated. The method according to claim 1,
Wherein the first finishing cover and the second finishing cover are made of a metal material, and the first protective sheet and the second protective sheet are fabric materials.

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