KR20160035834A - Method and structure for preventing water leakage of floor joint in building - Google Patents

Abstract

The present invention relates to a method and a structure for preventing a water leakage through a floor joint of a building. The method of preventing the water leakage through the floor joint, which is a floor boundary of upper and lower walls forming an outer wall of the building constructed by placing concrete into molds, includes: a step of arranging lower wall rebar for reinforcing the lower wall in a space between an inner wall mold and an outer wall mold and installing a groove unit frame on the upper inner surface of the outer wall mold; a step of forming a key-groove unit at a depth deeper than the width thereof in an upper part of the lower wall by removing the inner wall mold, the outer wall mold, and the groove unit frame after placing and curing concrete into the space; a step of connecting upper wall rebar to the lower wall rebar protruding upward from the upper part of the lower wall and arranging the bottom of the upper wall rebar to be adjacent to the bottom of the key-groove unit; and a step of interlocking a key unit protruding from the lower part of the upper wall to be integrated with the key-groove unit of the upper part of the lower wall when forming the upper wall on the top of the lower wall.

Description

METHOD AND STRUCTURE FOR PREVENTING WATER LEAKAGE OF FLOOR JOINT IN BUILDING

The present invention relates to a method and structure for preventing leakage of a floor joint of a building, and more particularly, to a method of preventing leakage of floor joints at a boundary of a wall when an apartment, a residence, And more particularly, to a method and structure for preventing leakage of a floor joint of a building.

In general, the construction of the apartment frame is further carried out one by one. For the realization of this, the exterior mold of the apartment is constructed by the large iron plate form or the gang form.

As a result of this construction, a layer joint of the wall occurs at the upper end of the bottom plate of each layer inevitably, and external rainwater enters the inside of the building through the gap of the floor joint through the layer joint, .

In the building, the floor joint is a boundary part between the lower wall formed by the line concrete pouring and the upper wall formed on the lower wall by the after concrete pouring, or the boundary part assembled facing each other by the precast concrete construction, Or ultrafine pores or gaps may inevitably be formed in the layer joint due to the precast construction characteristics.

Particularly, in the method of constructing a building by assembling a screen wall using precast concrete, a fishey wall having an outer wall assembling protrusion or a fitting groove is used as an outer wall of 10 mm or more (for example, 10 to 150 mm) have.

Such a protrusion or fitting groove of the visual wall has a width of 20 mm, a protruding length or a depth of 20 mm and is formed to have a size very small in comparison with the wall thickness. The main purpose is to induce concave- And it is used as a step for preventing leakage.

That is, in the gap between the concave-convex coupling projections or the concave-convex projections formed at the boundary between the outer wall or the face wall layer, foreign substances are introduced into the concrete pouring, curing, .

That is, in Patent Document 1, which is the background of the invention, waterproof performance can be expected only if a separate primary leakage blocking portion or secondary leakage blocking portion is provided in addition to the unevenness or protruding jaws. Accordingly, the construction is complicated, It is difficult to secure a waterproof performance due to hardening and cracking of the leak-barrier portion exposed during the operation.

In addition, in Patent Document 2, a leakage preventing jaw is formed on the side of the slab engaging portion so that the joint portion between the first and second visual walls is made single-layer, and the mortar and caulking material or horizontal joint material, have.

Particularly, since the projecting length of the waterproofing jaw to be joined in a single layer is relatively small, the inflow of external rainwater can not be prevented by only the waterproofing jaw itself.

In order to assemble the first and second visual walls, the second visual wall may be lifted to the first visual wall side and then lowered to the first visual wall side. Alternatively, in order to assemble the first visual wall and the second visual wall, There is a problem that the water leakage preventing jaw is separated from the second visible wall due to an impact caused by the contact with each other, and thus the waterproofing work is carried out or complicated maintenance work is required.

[Patent Literature]

(Patent Document 1) Korean Registration Practice No. 20-0329054 (September 25, 2003)

(Patent Document 2) Korean Patent Publication No. 10-2002-0089635 (November 30, 2002)

SUMMARY OF THE INVENTION The present invention has been made in order to solve the problems of the prior art described above, and it is an object of the present invention to provide a method of manufacturing a reinforced concrete pipe structure in which a lower wall reinforcing bar and an upper wall reinforcing bar are connected to each other, The present invention is to provide a method and structure for preventing leakage of a floor joint of a building, which can form a relatively deep and wide step stably by forming a relatively large and stable step in a key groove portion of a wall.

According to one aspect of the present invention, there is provided a method for preventing leakage of a floor joint in a floor joint between an upper wall and a lower wall forming an outer wall of a building constructed through concrete pouring, Disposing a lower wall reinforcing lower wall reinforcing bar in an inner space between the wall inner mold and the wall outer formwork and installing a groove boom on the upper inner surface of the wall outer formwork; Removing the wall inner formwork and the wall outer form and the grooved bouquet after concrete pouring and curing for the inner space to form a keyed portion having a depth greater than the width at the top of the bottom wall; Connecting the upper wall reinforcement to the lower wall reinforcement projecting upward from the upper end of the lower wall and placing the lower portion of the upper wall reinforcement of the outer row adjacent the bottom of the reinforcement; And joining the key portion formed integrally with the lower wall of the upper wall to the key groove of the upper end of the lower wall when the upper wall is formed on the upper wall of the lower wall. A water leakage prevention method is provided.

In addition, the molding step may include a step of installing a mold and a groove boom above the lower wall; Placing and pouring concrete for the upper wall into the mold; And fitting the key portion formed at the lower end of the upper wall through the curing to the key groove portion at the upper end of the lower wall in a state where the key portion is reinforced by the bottom portion of the upper wall reinforcement of the outer row.

In addition, the molding step may further include the step of forming a key portion having a depth greater than the width at the upper end of the upper wall through the curing.

In addition, the wall inner mold, the wall outer mold, and the grooved bouquet can be recycled for concrete pouring and curing of a plurality of outer wall bodies that are multi-layered to form a layer joint over the top wall.

The plurality of outer wall bodies may have a key groove formed at an upper end of a lower wall corresponding to one side of the outer wall body, and a lower wall reinforcement projecting upward from an upper end of the lower wall may be provided with an upper wall reinforcement The bottom portion of the upper wall reinforcement of the outer row is disposed adjacent to the bottom of the key groove portion and the key portion is formed at the lower end of the upper wall of the outer row so that the key portion reinforced by the bottom portion of the upper wall reinforcement is connected to the key groove portion It can be made through repetition of mutual fusion process.

According to another aspect of the present invention, there is provided a floor joint leakage prevention structure for a building, the floor joint being constructed by a layer joint leakage preventive structure of a building, wherein the key groove portion is formed in a shape corresponding to a groove booty coupled to the wall outer form, And the key portion is formed at an outer corner of a lower end of the upper wall so as to correspond to the key groove portion. Layer joint leakage prevention structure is provided.

The width and the depth of the key portion correspond to the width and the protrusion length of the key portion and form a relatively deep and wide stepped portion between the key portion and the key portion as compared with the unevenness for fitting.

The key portion is reinforced by a bottom portion of the upper wall reinforcing bars of the outer row adjacent to the bottom of the key groove portion, connected to a lower wall reinforcing portion protruding upward from an upper end of the lower wall, so as not to be separated from the upper wall.

According to the present invention, there is provided a method of preventing leakage of floor joints of a building, wherein a key groove portion having a depth greater than the width at the time of pouring concrete is formed at the upper end of the lower wall, A key portion is formed at the lower end of the upper wall.

At this time, the key groove portion and the key portion are provided in the layer joint corresponding to the boundary between the lower wall and the upper wall as relatively deep and wide stepped portions as compared with the unevenness for the custom assembly.

As a result, even if no additional waterproofing member is provided, external rainwater can be originally prevented from flowing into the building through the fine groove of the key groove portion and the key portion having a relatively deep and wide step.

The present invention also relates to a method of connecting a lower wall reinforcement of a lower wall and an upper wall reinforcement of an upper wall to each other before a concrete is poured, wherein a bottom of the upper wall reinforcement is disposed adjacent to a bottom of the keyway, The cushion of the upper wall is reinforced by the upper wall reinforcement of the inner wall of the upper wall to protect the detachment of the kiss from the external impact and the overall construction efficiency can be increased due to the reduction of unnecessary maintenance work have.

In addition, the leakage preventing structure realized by the layer joint leakage preventing method of the present invention can solve the leakage problem only by the concrete pouring and curing without using a separate leakage preventing portion, mortar, caulking material or horizontal jointing material It is effective.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a flow diagram of a method for preventing floor joint leakage of a building according to an embodiment of the present invention.
FIG. 2 is a perspective view showing the step of installing the lower wall reinforcing bar shown in FIG. 1, the formwork and the groove reinforcement. FIG.
FIG. 3 is a perspective view showing a step of forming a key groove portion having a depth greater than the width at the upper end of the lower wall shown in FIG. 1;
FIG. 4 is a perspective view showing the connection step of the lower wall reinforcement and the upper wall reinforcement shown in FIG. 1; FIG.
FIG. 5 is a perspective view showing a joining step between a key part formed at the lower end of the upper wall shown in FIG. 1 and a key groove formed at the upper end of the lower wall.
6 is an enlarged cross-sectional view of the circle A shown in Fig.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description of the present invention, detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

1 is a flowchart illustrating a method of preventing a floor joint leakage in a building according to an embodiment of the present invention.

Referring to FIG. 1, the present embodiment provides a method and structure for preventing water leakage in a floor joint of a building constructed through pouring concrete into a form.

Here, the layer joint corresponds to the interlayer boundary of the lower wall and the upper wall constituting the outer wall. For example, as the upper wall is newly installed on the lower wall poured with concrete, But it may actually refer to the boundary layer region where fine gaps exist.

The present embodiment is characterized in that the waterproofing material, waterproofing material, caulking material, gap sealing mold, horizontal jointing material, etc., which are installed separately in the layer joint, Leakage can be blocked by combining the groove and the key.

In order to prevent the leakage of water, the key groove portion and the key portion form a relatively deep and wide stepped portion compared with the concavo-convex portion for custom assembly, and may have a structure in which the key portion is not broken, detached, or dropped from the upper wall.

In order to construct such a structure, the present embodiment includes a step of disposing a lower wall reinforcing lower wall reinforcing bar in an inner space between an inner side wall formwork and a wall outer formwork, and installing a groove boom on the upper inner surface of the wall outer formwork ).

Here, the step S10 of installing the formwork, the lower wall reinforcing bar, and the grooved boule may be described in detail with reference to FIG.

FIG. 2 is a perspective view showing the step of installing the lower wall reinforcing bars, the formwork and the groove reinforcement shown in FIG. 1. FIG.

Referring to FIG. 2, the wall inner mold 110 and the wall outer mold 120 are structural members of various molds 100 used for constructing the building through concrete pouring and curing. In other words, the wall inner mold 110 and the wall outer mold 120 are formed on the lower wall of the floor joint FJ at the outer wall of the building as a boundary between the floor joints or the upper wall .

In particular, the groove 130 may be a member that is removably formed through a set of bolts and nuts 140 on the upper inner surface of the wall outer mold 120 to form a keyway in the lower wall. Here, the grooved bobbin 130 may be a square bar or a hollow square pipe having the same material as the shape material.

For example, a plurality of stud bolts corresponding to a set of bolts and nuts 140 are provided on the outer side of the groove 130, and a plurality of stud bolts corresponding to the set of bolts and nuts 140 are provided on the upper side of the wall outer mold 120, A bolt hole may be formed on the surface of the stud bolt so as to penetrate through the same place as the extending direction and position of the stud bolt.

The screw shaft of the stud bolt of the groove booster 130 is protruded through the bolt hole and the screw shaft of the nut 130 is inserted into the screw shaft So that the grooved bobbin 130 and the wall outer mold 120 can be joined together. Of course, when the nut is loosened, the groove boot 130 can be detached from the wall outer mold 120.

The mold frame 130 may be detachably attached to the wall outer mold 120 or the corresponding gang form, but it is also preferable that the mold outer mold 120 may be coupled to or integrated with the outer mold 120 In this case, it is possible to easily arrange and separate the mold frame 130 only by installing and disassembling the mold.

The lower wall reinforcing bars 210 and 220 are installed in an inner space M between the wall inner mold 110 and the wall outer mold 120. [ The upper portion of the lower wall reinforcing bars 210 and 220 may protrude upward by a predetermined length above the floor joint FJ so as to be connected to the upper wall reinforcing bars.

Particularly, among the lower wall reinforcing bars 210 and 220, the lower wall reinforcing bars 210 of the inner row are spaced apart from the inner side of the groove booth 130 by a predetermined distance E along the lower wall thickness direction (Y axis direction) (Z-axis direction), which is a direction perpendicular to the lower wall, and are spaced apart along the horizontal extending direction (X-axis direction) of the lower wall.

The lower wall reinforcing bars 220 of the outer row are also spaced apart from each other in the horizontal extending direction (X-axis direction) of the lower wall and are arranged in the height direction (Z-axis direction) Respectively.

In addition, the lower wall reinforcing bars 210 and 220 may be connected to the horizontal reinforcing bars 230 spaced apart in the height direction to form a lattice or mesh structure.

1 and 2, a mold 100 is installed at the upper and lower portions of a ceiling space N for forming a ceiling wall in the interior direction of the building from the upper end of the lower wall, A barrier bar reinforcement 240 is installed. At this time, the ceiling wall reinforcing bars 240 may be connected to the lower wall reinforcing bars 210 and 220.

Thereafter, concrete is poured into the internal space M and the ceiling space N between the wall inner mold 110 and the wall outer mold 120, and the poured concrete is cured for a predetermined period.

In addition, when the curing is completed, the mold 100, the wall inner mold 110, the wall outer mold 120, and the grooved boule 130 are removed, and the state shown in FIG. 3 can be obtained.

FIG. 3 is a perspective view showing a step of forming a key groove portion having a depth greater than the width at the upper end of the lower wall shown in FIG. 1. FIG.

Referring to FIGS. 1 and 3, a key groove 250 having a depth greater than a width may be formed at the upper end of the lower wall 200 (S20).

The key groove part 250 is formed in the wall outer mold 120 and the groove boot 130 and opens the outer surface of the key groove part 250 to the outside of the lower wall 200. The key groove portion 250 is formed below the inner surface 251 of the key groove 250 formed at the upper outer corner of the lower wall 200 and the upper surface of the lower wall 200 to form a step or step And the bottom 252 of the key groove portion 250 is formed.

The key groove portion 250 is formed along the entire circumference of the building.

The lower wall reinforcement 220 of the outer row among the lower wall reinforcements 210 and 220 protruding upward from the upper end of the lower wall 200 is arranged adjacent to the inner side 251 of the key groove 250.

FIG. 4 is a perspective view showing the connection step of the lower wall reinforcing bar and the upper wall reinforcing bar shown in FIG. 1. FIG.

1 and 4, the present embodiment is characterized in that upper wall reinforcing bars 310 and 320 are connected to lower wall reinforcing bars 210 and 220 protruding upward from the upper end of a lower wall 200, (S30) of the bottom portion 320a of the key groove portion 250 adjacent to the bottom portion 252 of the key groove portion 250.

Since the bottom portion 320a of the upper wall reinforcing bar 320 of the outer row extends to the bottom 252 of the key groove portion 250, it plays a role of reinforcing the key portion located in the key groove portion 250 when the concrete of the upper wall is poured. And as a result, the key portion can be prevented from falling off the upper wall. Further, since the key portion is reinforced by the bottom portion 320a of the upper wall reinforcing bar 320 in the outer row, even if the protruding length of the key portion is relatively larger than the general unevenness, the structure can be secured.

In addition, the lower wall reinforcing bars 210 and 220 and the upper wall reinforcing bars 310 and 320 are connected to each other using reinforcing bar connecting means 212, which is typically used for reinforcing bar construction before concrete is poured. Here, the reinforcing bar connecting means 212 may be a bushing type fastening member having a bi-directional nut to be screwed to a male screw of a reinforcing bar, when the reinforcing bar connecting means 212 is a wire, clip, or a screw capable of screwing.

Further, the upper wall reinforcing bars 310 and 320 are further connected to a not shown horizontal reinforcing bar for upper walls.

Thereafter, step S40 is performed in which the formwork and the grooved bobbin (not shown) are installed above the lower wall 200 in the same manner as step S10 described above.

Here, the upper wall mold is installed so as to extend in the height direction with the lower wall 200 as a supporting base.

That is, the lower wall 200 is further provided with protruding members such as various anchor members, protruding pin members, protruding stud bolts, and the like, which are not shown, and the upper wall mold can be connected to these protruding members.

In addition, the upper wall mold may be installed so as to extend in a height direction on a support base (not shown) after the lower wall 200 has been formed.

Thereafter, after the concrete is poured and cured with respect to the inner space of the upper wall mold, the corresponding mold groove bucket is removed, and the state as shown in FIG. 5 can be obtained.

FIG. 5 is a perspective view illustrating a joining step between a key portion formed at the lower end of the upper wall shown in FIG. 1 and a keyway portion formed at the upper end of the lower wall.

1 and 5, in the present embodiment, when the upper wall 300 is formed by pouring concrete on the upper part of the lower wall 200, 350 are fitted to the key groove 250 of the upper end of the lower wall 200 (S50).

That is, during the pouring of the concrete in the upper wall 300 in the step S50, a step of installing the formwork and the groove booth in a manner similar to or the same as that described in FIG. 2 above the lower wall 200, The upper portion of the upper wall 300 and the lower portion of the upper wall 320 are formed with a plurality of concave portions 320a and 320b, The key groove 250 of the upper wall of the lower wall 200 is formed.

Step S50 is a step S51 of forming a key groove 305 at a depth greater than the width of the top wall 300 through concrete pouring and curing of the top wall 300, .

In this embodiment, various forms, namely, the wall inner formwork, the wall outer formwork, and the grooved bouquet are recycled for concrete pouring and curing of a plurality of outer wall bodies 400, .

That is, the key portion 450 of the other outer wall body 400 to be formed above the upper wall 300 may be formed in the key groove portion 305 of the upper wall 300.

For example, the plurality of outer wall bodies 400 may be formed by forming a key groove at the upper end of the lower wall corresponding to one side of the outer wall body 400 described above, The upper wall reinforcement of the upper wall corresponding to the other side of the upper row is connected to the lower side of the upper wall and the lower portion of the upper wall reinforcement of the outer row is disposed adjacent to the bottom of the key groove, Can be made by repeating the process of mutually combining the key portions reinforced by the bottom portions of the key portions with the key groove portions.

The outer wall member 400 corresponds to the upper wall described above and the upper wall 300 is located below the outer wall member 400 with respect to the outer wall member 400. In this case, It can be seen that the upper wall 300 mentioned above is a lower wall with respect to the outer wall body 400.

In particular, the upper end of the upper wall reinforcements 310 and 320 protruding upward from the upper wall 300 corresponds to the protruded lower wall reinforcement described above with reference to the outer wall body 400. That is, the upper end portions of the protruded upper wall reinforcing ribs 310 and 320 are connected to the reinforcing ribs (not shown) for the outer wall body 400 as the protruding lower wall reinforcing ribs described above, so that the upper wall reinforcing ribs 310 and 320 have bent portions 311 and 321 .

The upper wall reinforcing ribs 310 and 320 can be aligned and connected to the reinforcing bars for the outer wall body 400 by the bent portions 311 and 321.

6 is an enlarged cross-sectional view of the circle A shown in Fig.

Referring to FIG. 6, the present embodiment provides a leakage prevention structure by the layer joint leakage preventing method of the building described above.

Here, the key groove 250 corresponds to the groove boom having the same volume as the groove boom to be coupled to the outer wall of the wall, and a depth D larger than the width W at the upper outer corner of the lower wall 200 Is formed along the entire perimeter of the building in the floor joint (FJ).

The key portion 350 is formed at the lower outer corner of the upper wall 300 so as to be matched with the key groove portion 250.

The width W and the depth D of the key groove 250 may be formed to correspond to the width and the protrusion length of the key part 350. [ For example, the width W of the key groove 250 or the width of the key 350 may be 60 mm, and the depth D of the key groove 250 or the protrusion length of the key 350 may be 80 mm .

Here, the dimension for the width W and the depth D may not prevent leakage when the dimension is less than the dimension, and when the dimension is more than the dimension, it is required to use an excessive material for cone pouring, The durability of the key part 350 may not be ensured by only the bottom part 320a of the key part 320. This may be a critical value that the key part 350 is not detached and can exhibit the water leakage function.

The numerical values of the width W and the depth D of the key groove 250 or the width and the protrusion length of the key portion 350 can be selected in accordance with the scale of the building and the thickness of the outer wall, The size of the building or the wall thickness of the outer wall may be taken into account so as to be equal to or less than the above-mentioned dimension.

A relatively deep and wide step Q is formed between the key groove 250 and the key portion 350 by the width W and the depth D.

Even if rainwater outside the building partially flows into the clearance starting position portion of the floor joint FJ, the flow of the rainwater is obstructed by the deep and wide step Q as described above. Therefore, the rainwater does not flow into the inside corner C of the building, and as a result, leakage of the building can be intrinsically blocked.

As described above, the key portion 350 is connected to the lower wall reinforcing bar 220 protruding upward from the upper end of the lower wall 200 so as not to be broken or separated from the upper wall 300 by breakage or impact. Is reinforced by the bottom portion 320a of the upper wall reinforcement 320 of the outer row adjacent to the bottom of the key groove portion 250 so as to be stably structurally structured and without attaching another leakage preventing member as before, Leakage of the building can be prevented by the structure and the shape characteristic of the key groove portion 350 and the key groove portion 250.

100: die 130: home bucket
200: lower wall 210, 220: lower wall reinforcing bar
250, 305: key groove portion 300: upper wall
310, 320: upper wall reinforcing bar 350, 450:
400: Outer wall

Claims (8)

A method for preventing leakage in a floor joint corresponding to an interlayer boundary of a lower wall and an upper wall constituting an outer wall of a building constructed through concrete pouring by a form,
Disposing the lower wall reinforcing lower wall reinforcement in an inner space between the wall inner formwork and the wall outer formwork and installing a groove boom on the upper inner surface of the wall outer formwork;
Removing the wall inner formwork and the wall outer form and the grooved bouquet after concrete pouring and curing for the inner space to form a keyed portion having a depth greater than the width at the top of the bottom wall;
Connecting the upper wall reinforcement to the lower wall reinforcement projecting upward from the upper end of the lower wall and placing the lower portion of the upper wall reinforcement of the outer row adjacent the bottom of the reinforcement; And
And joining the key portion formed integrally protruding from the lower end of the upper wall to the key groove of the upper end of the lower wall when the upper wall is formed on the upper wall of the lower wall. How to prevent.
The method according to claim 1,
Wherein the step of combining comprises:
Installing a mold and a groove boom above the lower wall;
Placing and pouring concrete for the upper wall into the mold; And
And joining the key portion formed at the lower end of the upper wall through the curing to the upper key groove portion of the lower wall in a state where the key portion is reinforced by the bottom portion of the upper wall reinforcement of the outer row. How to prevent joint leakage.
3. The method of claim 2,
Wherein the step of combining comprises:
And forming a key portion having a depth greater than the width at the upper end of the upper wall through the curing.
The method according to claim 1,
Wherein the wall inner formwork, the wall outer form, and the grooved bouquet are recycled for concrete pouring and curing of a plurality of outer wall bodies formed as multi-layers with a layer joint over the upper wall.
5. The method of claim 4,
The plurality of outer wall bodies may have a key groove formed at an upper end of a lower wall corresponding to one side of the outer wall body and connected to a lower wall wall protruding upward from an upper end of the lower wall to connect upper wall reinforcing bars of the upper wall corresponding to the other side of the outer wall body The bottom portion of the upper wall reinforcement of the outer row is disposed adjacent to the bottom of the key portion and the key portion is formed at the lower end of the upper wall of the outer row so that the key portion reinforced by the bottom portion of the upper wall reinforcement Wherein the floor joint is constructed by repeating the process of making the floor joint.
In the structure made by the layer joint leakage preventing method of the building of claim 1,
The keyway portion being formed along the entire periphery of the building in the layer joint so as to have a depth greater than a width at an upper outer corner of the lower wall corresponding to a groove boot coupled to the wall outer mold,
Wherein the key portion is formed at an outer corner of a lower end of the upper wall so as to correspond to the key groove portion.
The method according to claim 6,
Wherein a width and a depth of the key groove are formed to correspond to a width and a protrusion length of the key and a relatively deep and wide step is formed between the key groove and the key, Joint leakage prevention structure.
8. The method of claim 7,
[0028]
Is reinforced by a bottom portion of the upper wall reinforcement of the outer row adjacent to the bottom of the keyway portion, connected to the lower wall reinforcement projecting upward from the upper end of the lower wall, so as not to fall off from the upper wall Leakproof structure.

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