JP7691356B2 - Gap cover and gap closing method - Google Patents

Description

The present invention relates to a gap cover and a method for closing a gap.

In the past, there have been many cases where various types of evacuation stairs, such as special evacuation stairs used in multi-story buildings, were made of steel, and in such cases, gaps were sometimes formed between the girders supporting the steps (treads) and the finishing materials of the walls of the building, for example, to ensure clearance during construction. In addition, such gaps were sometimes closed with gap covers to ensure safety and improve appearance.
For example, the gap cover in Patent Document 1 includes an angle-shaped cover body placed in the gap, multiple vertical pieces attached to the cover body, and a support bolted to the truss and positioned on the wall side. The support tightens and holds the vertical pieces inserted from above between the support and the truss, and fixes the cover body to the truss, thereby closing the gap.

JP 2003-13574 A

Conventional gap covers are easy to install because the vertical pieces can be held in place by tightening bolts from the staircase side, but they require multiple types of parts and fasteners such as bolts, which inevitably increases costs. In addition, the stringer needs to have holes for the bolts and holes for the rotation prevention tabs formed on the supports, so the effort and cost at the manufacturing stage must also be considered. Therefore, there is a need to easily and inexpensively close the gap between the stringer and the wall finishing material with one type of cover material.
However, the dimensions of the gaps that form between the truss beams and the wall finishing materials are not necessarily consistent from floor to floor of a building or from wall finishing material to wall finishing material, making it difficult to close the gaps with only one type of cover material.

The present invention was made in consideration of the above circumstances, and its objective is to ensure that the gap between the truss and the wall finishing material can be reliably closed with a single type of cover material even if the gap is not of a fixed size, thereby improving workability and reducing costs.

In order to solve the above problems, the present invention provides a staircase having a mounting part attached to an edge of a staircase beam,
A protruding plate portion protruding to one side from one side surface of the mounting portion;
A corrugated plate portion further protrudes to one side from the tip of the protruding plate portion in the protruding direction and is formed in a state in which mountain folds and valley folds are alternately repeated at a constant width.
The mounting portion, the protruding plate portion and the corrugated plate portion are integrally formed, and have a feature that the same cross-sectional shape continues in the longitudinal direction.

The invention described in claim 2 is the gap cover described in claim 1,
The corrugated plate portion has a plurality of mountain folds and a plurality of valley folds,
The plurality of mountain folds are characterized in that they are located on extensions of the protruding plate portion.

The invention described in claim 3 is the gap cover described in claim 1 or 2,
The protruding plate portion is characterized in that a holding portion is integrally formed on the rear side surface thereof, into which a rod-shaped joint member is inserted and which holds the joint member.

The invention described in claim 4 is a method for closing a gap formed between a wall finishing material of a building and the braided beam by using the gap cover described in any one of claims 1 to 3 ,
Depending on the size of the gap,
The method is characterized in that the corrugated plate portion is partially cut off from the tip side in the projection direction and then the mounting portion is attached to the end edge portion of the stringer, or the corrugated plate portion is contracted while the mounting portion is attached to the end edge portion of the stringer.

According to the present invention, even if the gap between the slat beam and the wall finishing material is not of a fixed size, it can be reliably closed with a single type of cover material, improving workability and reducing costs.

This is a perspective view showing a steel staircase equipped with a braided beam. FIG. 4 is an end view showing the attached state of the gap cover. FIG. 11 is an end view illustrating a state in which the gap is closed by the gap cover. 11 is a side view showing a state in which a plurality of gap covers are connected in a straight line in the length direction and at different angles in the up-down direction. FIG. FIG. 13 is a perspective view showing a state in which a plurality of gap covers are connected in a row at different angles in an orthogonal direction.

The following describes the embodiments of the present invention with reference to the drawings. However, the embodiments described below are subject to various limitations that are technically preferable for implementing the present invention, but the technical scope of the present invention is not limited to the following embodiments and illustrated examples. Note that the directions in the following embodiments and illustrated examples are set solely for the convenience of explanation.

In Fig. 1, reference numeral 1 denotes a stairwell. The stairwell 1 is a space formed inside a building, in which a staircase 3 is installed, and is surrounded by walls.
The surrounding walls are finished with wall finishing material 2 exposed inside the staircase 1.
The staircase 3 is a steel-framed, turn-around staircase with a landing 3a, and includes a pair of parallel-arranged girders 4, and a plurality of step plates 5 and risers 6 that are provided and supported between the pair of girders 4. In addition, a frame plate 3b that is continuous with the girders 4 is provided around the landing 3a.
In this embodiment, the staircase 3 is a return staircase made of steel and installed indoors, but is not limited to this. In other words, it may be an outdoor staircase that is not installed in the staircase room 1, or a type of staircase other than a return staircase. It may also be a wooden staircase, and may not have a riser 6. In any case, the staircase 3 is equipped with a slat 4 and a plurality of step plates 5.

The rafter 4 located on the wall finishing material 2 side is arranged with a gap S between it and the wall finishing material 2. The rafter 4 is inclined along the ascending and descending direction of the stairs 3, and the inclined edge portion 4a protrudes above the upper surfaces of the plurality of step plates 5.
The gap S is formed for the purpose of, for example, ensuring clearance during construction of the staircase 3. Such a gap S is closed by a gap cover 10 to ensure safety and improve appearance.

As shown in Figure 2, the gap cover 10 comprises an attachment portion 11, an overhanging plate portion 12, and a corrugated plate portion 13, and the attachment portion 11, the overhanging plate portion 12, and the corrugated plate portion 13 are integrally formed as an extrusion molded product having a continuous, uniform cross-sectional shape in the longitudinal direction.
Although the material of the gap cover 10 in this embodiment is polyvinyl chloride resin, other materials that can be extruded may be used.

The mounting portion 11 is a portion that is attached to the end edge portion 4a of the sash 4, and has a central plate portion 11a, a first side plate portion 11b, and a second side plate portion 11c, and is formed into an approximately C-shaped (concave, J-shaped) cross section.
The central plate portion 11a is a plate portion that contacts the end face of the slat 4 (the upper surface of the end edge portion 4a).
The first side plate portion 11b is a plate portion that is integrally formed with one end portion (left end portion) of the central plate portion 11a and contacts one side surface (left side surface) of the sash beam 4.
The second side plate portion 11c is a plate portion that is integrally formed with the other end portion (right end portion) of the central plate portion 11a and contacts the other side surface (right side surface) of the sash beam 4.

The first side plate portion 11b is formed longer downward than the second side plate portion 11c. In other words, it is set longer in the direction away from the central plate portion 11a. This is because the protruding plate portion 12 and the corrugated plate portion 13 are provided protruding toward the first side plate portion 11b, and are capable of supporting the weight of the protruding plate portion 12 and the corrugated plate portion 13 and the movement of the corrugated plate portion 13, which flexes due to its elasticity.

The mounting portion 11 is adhesively fixed to the end edge portion 4a of the slat 4 using an adhesive such as a modified silicone adhesive.
The distance between the first side plate portion 11b and the second side plate portion 11c is set to be approximately equal to or slightly wider than the thickness dimension of the end edge portion 4a of the slat 4, so that the adhesive can be reliably filled.

The protruding plate portion 12 is a plate-shaped portion that protrudes to one side (left side) from one side surface (left side surface) of the mounting portion 11 .
The protruding plate 12 in this embodiment is integrally formed at a corner portion of the mounting portion 11 that is formed by the central plate 11a and the first side plate 11b, and the surface (top surface) of the protruding plate 12 and the surface (top surface) of the central plate 11a are flush with each other. However, this is not limited to this, and the protruding plate 12 may be provided below the central plate 11a, forming a step between the protruding plate 12 and the central plate 11a.
In addition, the inside corner formed by the mounting portion 11 and the overhanging plate portion 12 has a curved surface, and the plate thickness is accordingly slightly thicker. This makes it easier to support the weight of the overhanging plate portion 12 and the corrugated plate portion 13 and the movement of the corrugated plate portion 13, which bends due to its elasticity.

A holding portion 12a is integrally formed on the rear side of the overhanging plate portion 12, into which a rod-shaped joint member J is inserted to hold the joint member J. The joint member J is used when connecting two gap covers 10 together in the longitudinal direction. The holding portion 12a is made up of one and the other holding pieces formed in a hook shape, and these one and the other holding pieces are arranged with a gap between them. Therefore, the one and the other holding pieces have some elasticity, making it easy to insert the joint member J.

The corrugated plate section 13 is a section that protrudes further to one side (left side) from the protruding end (left end) of the protruding plate section 12, and is formed in a state in which mountain folds and valley folds are repeated alternately at a constant width. Therefore, the corrugated plate section 13 is easy to expand and contract in the protruding direction and the opposite direction (left-right direction), and is easy to swing on the front side and back side (up-down direction) of the protruding plate section 12. In other words, the corrugated plate section 13 has a shape that exhibits elasticity in a direction perpendicular to its own length direction. Therefore, when the corrugated plate section 13 contracts in the opposite direction to the protruding direction (towards the protruding plate section 12), it tries to return to the protruding direction (towards the wall finishing material 2).

More specifically, the corrugated plate portion 13 is formed like a plate in a corrugated shape (bellows-like, accordion-like), and has a plurality of mountain folds 14 located at the top and a plurality of valley folds 15 located at the bottom. In this embodiment, the plate constituting the corrugated plate portion 13 is bent downward from the tip of the protruding plate portion 12 in the protruding direction, and the plate extending downward is bent upward at a predetermined position to form the first valley fold 15 from the right. Then, the plate extending upward is bent downward at a predetermined position to form the first mountain fold 14 from the right. Such mountain folds and valley folds are alternately repeated at a constant width to form the corrugated plate portion 13 as shown in FIG. 2.
The plurality of mountain folds 14 are located on the extension lines of the central plate portion 11a and the protruding plate portion 12 in the mounting portion 11. In other words, the uppermost position where the plate constituting the corrugated plate portion 13 is bent is set to be equal to the height positions of the central plate portion 11a and the protruding plate portion 12 in the mounting portion 11.

The width dimension W1 of the surface (upper surface) on the outer corner side of the mountain fold 14 is set to be longer than the width dimension W2 of the surface (lower surface) on the outer corner side of the valley fold 15. In other words, the surface on the outer corner side of the mountain fold 14 is formed wider. The mountain fold 14, which is located on the extension line of the central plate portion 11a of the mounting portion 11, is exposed to the surface like the central plate portion 11a and the protruding plate portion 12, so it is more likely to reflect light, which may improve its appearance.

Furthermore, of the mountain fold 14 and the valley fold 15, at least the surface of the outer corner of the mountain fold 14 has a notched groove 14a formed along the length direction.
In this embodiment, a notched groove 14b is also formed along the length direction on the surface of the inner corner of the mountain fold 14. Furthermore, a notched groove 15a is also formed along the length direction on the surface of the outer corner of the valley fold 15.
The notch grooves 14a, 14b, and 15a function as lines that serve as markers when cutting off a portion of the corrugated plate portion 13 from the tip side in the projection direction. That is, for example, on-site, notches can be made along the notch grooves 14a, 14b, and 15a with a cutter, and the corrugated plate portion 13 can be cut off from the cut portions. Alternatively, depending on the depth of the notch grooves 14a, 14b, and 15a, the corrugated plate portion 13 can be cut off manually without using a cutter.

In this embodiment, in a normal state, the corrugated plate portion 13 has three mountain folds 14 and four valley folds 15. The end of the corrugated plate portion 13 located at the tip end (left end) in the projection direction is closest to the wall finishing material 2 and is therefore referred to as the wall side end 140. This wall side end 140 is pushed against the wall finishing material 2 by the elasticity of the corrugated plate portion 13. When the gap cover 10 is attached to the end edge portion 4a of the sash 4, the gaps between the mountain folds 14 in the corrugated plate portion 13 are exposed, so the gaps between the mountain folds 14 may be filled with, for example, a caulking material (wet sealing material) to fill the gaps and make them flush with the surfaces of the central plate portion 11a and the projection plate portion 12. The caulking material to be filled is preferably the same color as the gap cover 10 or transparent (colorless), but it is also possible to devise a way to improve the design by filling a caulking material of a different color.

The position of the wall side end 140 changes depending on which mountain fold 14 of the corrugated plate portion 13 is cut off at its tip in the protruding direction.
When cutting off a portion of the corrugated plate portion 13 from the tip side in the projection direction, the cutting is basically performed at the position of the mountain fold portion 14. Cutting off at the position of the mountain fold portion 14 leaves a wide upper surface even after cutting off, and the wall side end portion 140 is positioned on an extension line of the central plate portion 11a of the mounting portion 11, which gives a good appearance. However, this is not limited to this, and the cutting may be performed at the position of the valley fold portion 15.

As described above, the corrugated plate portion 13 has a shape that exhibits elasticity in a direction perpendicular to its length direction, so that when the stairs 3 sway due to an earthquake or the like and move toward or away from the wall finishing material 2, the corrugated plate portion 13 may only need to expand and contract. In other words, the influence of the swaying of the stairs 3 on the protruding plate portion 12 and the mounting portion 11 is less likely to be felt, so damage to the protruding plate portion 12 and the mounting portion 11 can be prevented. As described above, even if caulking material is filled into the gaps between the mountain folds 14, the caulking material exhibits a certain degree of elasticity and does not significantly impede the expansion and contraction deformation of the corrugated plate portion 13.

To close the gap S formed between the rafter 4 located on the wall finishing material 2 side and the wall finishing material 2 using the gap cover 10 configured as described above, as shown in Figure 3, depending on the dimension of the gap S, the corrugated plate portion 13 is partially cut off from the tip side in the protruding direction and then the mounting portion 11 is mounted to the end edge portion 4a of the rafter 4, or the corrugated plate portion 13 is contracted and the mounting portion 11 is mounted to the end edge portion 4a of the rafter 4.
That is, the corrugated plate portion 13 functions as a portion for adjusting the gap between the protruding plate portion 12 and the wall finishing material 2. When adjusting the gap, there are a pattern in which the corrugated plate portion 13 is partially cut off from the tip side in the protruding direction, a pattern in which the corrugated plate portion 13 is shrunk without being cut off, and a pattern in which the corrugated plate portion 13 is cut off and then shrunk.
In addition, when the length of the gap cover 10 from one side of the slat 4 to the wall side end 140 of the corrugated plate portion 13 is equal to the dimension of the gap S, there is no need to shrink the corrugated plate portion 13.

Fig. 3 shows a state in which the gap S is closed by the gap cover 10. The dimensions of each gap S shown in Fig. 3(a) to (d) are different, with the dimensions decreasing in order from Fig. 3(a) onwards.
3(a) shows an example in which the gap S is closed by the gap cover 10 without cutting off the corrugated plate portion 13. The wall side end portion 140 is in contact with the wall finishing material 2.
3(b) shows an example in which the corrugated plate portion 13 is partially cut away at the positions of the notched grooves 14a, 14b in the middle mountain fold portion 14 out of the three mountain fold portions 14. The wall side end portion 140 is in contact with the wall finishing material 2.
3(c) shows an example in which the corrugated plate portion 13 is partially cut off at the positions of the notched grooves 14a, 14b in the mountain fold portion 14 that is located closest to the protruding plate portion 12 among the three mountain fold portions 14. The wall side end portion 140 is in contact with the wall finishing material 2.
3(d) shows an example in which the corrugated plate portion 13 is partially cut off at the position of the notch groove 15a in the valley fold portion 15 that is located closest to the protruding plate portion 12 among the four valley fold portions 15. The remaining corrugated plate portion 13 shrinks to the opposite side to the protruding direction and is entirely in contact with the wall finishing material 2.
3, the gap S can be reliably closed by the gap cover 10. In other words, even if the dimensions of the gap S are different, it can be closed by one type of gap cover 10.

The gap covers 10 are long, for example, each measuring about 2000 to 3000 mm. As shown in Figures 4 and 5, multiple such long gap covers 10 may be used and connected in a straight line along the length, or connected at different angles. In other words, by connecting multiple gap covers 10, it is possible to prevent gaps S from appearing from the top to bottom of the stairs 3 leading from the lower floor to the upper floor of a building.

Figure 4 shows an example in which multiple gap covers 10 are attached to the end edge 4a of a slat 4 whose lower and upper ends extend horizontally and whose space between the lower and upper ends extends diagonally, thereby blocking the gap S between the wall finishing material 2.
When attaching the gap cover 10 to the edge portion 4a of the slat 4 in such a form that the angle changes vertically midway, the end portion in the length direction of the gap cover 10 is cut at a predetermined angle. If the angle of the diagonal portion with respect to the horizontally extending portion of the slat 4 is set to, for example, 130 degrees (a step gradient of 50 degrees), the adjacent ends of the multiple gap covers 10 can be cut at 65 degrees in a side view to connect the multiple gap covers 10 together at the desired set angle. In other words, it is sufficient to cut at an angle that is half the set angle.
When multiple gap covers 10 are connected in a straight line in the length direction, there is no need to cut them, but it is preferable to increase the unity by connecting them with a joint member J. If an angled joint member J is used, multiple gap covers 10 that are connected at different angles can also be connected to each other.

Figure 5 shows a state in which multiple gap covers 10 are connected in a row to close a gap S between a wall finishing material 2 and a part where the angle changes in a cross direction when viewed in a plane, such as a frame plate 3b at the corner of a landing 3a.
Even when connecting at different angles along the horizontal direction in this way, the ends of the gap covers 10 in the length direction are cut at a predetermined angle. For example, when changing the angle to a right angle in a plan view, by cutting adjacent ends of multiple gap covers 10 at 45 degrees in a plan view, multiple gap covers 10 can be connected together at a right angle.
If an angled joint member J is used, it is also possible to connect a plurality of consecutive gap covers 10 at different angles.

The gap cover 10 as described above is attached to the upper edge 4a of the rafter 4, but it may also be attached to the lower edge 4a of the rafter 4. This makes the stairs 3 look good because the gap S between the rafter 4 and the wall finishing material 2 can be blocked by the gap cover 10 when looking up at the stairs 3 from below.

In addition, since the corrugated plate portion 13 is manufactured from polyvinyl chloride resin or other materials that can be extruded as described above, the portion of the corrugated plate portion 13 that is cut off according to the dimensions of the gap S may be recyclable. Recycling is preferable because it can reduce costs.

According to this embodiment, the following excellent effects are obtained.
In other words, the gap cover 10 comprises an attachment part 11 that is attached to the end edge 4a of the rafter 4 of the staircase 3, an extension plate part 12 that extends to one side from one side of the attachment part 11, and a corrugated plate part 13 that extends further to one side from the tip of the extension direction of the extension plate part 12 and is formed in a state in which mountain folds and valley folds are repeated alternately at a constant width.Since the attachment part 11, the extension plate part 12 and the corrugated plate part 13 are formed integrally and have the same cross-sectional shape continuing in the longitudinal direction, simply by attaching the attachment part 11 to the end edge 4a of the rafter 4, the extension plate part 12 and the corrugated plate part 13 can close the gap S formed between the rafter 4 and the wall finishing material 2.
The corrugated plate portion 13 is formed in a state where mountain folds and valley folds are alternately repeated at a constant width, so that it is easy to expand and contract in the protruding direction and the opposite direction, and is easy to swing to the front side and back side of the protruding plate portion 12. In other words, the corrugated plate portion 13 has a shape that exhibits elasticity in a direction perpendicular to its own length direction. Therefore, even if the dimension of the gap S between the stringer 4 and the wall finishing material 2 is short, the protruding plate portion 12 and the corrugated plate portion 13 can be arranged in the gap S by contracting the corrugated plate portion 13, so that the protruding plate portion 12 and the corrugated plate portion 13 can close the gap between the stringer 4 and the wall finishing material 2. If the dimension of the gap S is even shorter, the corrugated plate portion 13 may be partially cut off from the tip side in the protruding direction.
As a result, even if the gap S between the slat 4 and the wall finishing material 2 is not of a fixed size, it can be reliably closed by the gap cover 10, which is a single type of cover member, improving workability and reducing costs. In addition, since no processing is required on the staircase 3 side to attach the gap cover 10, it also contributes to reducing the overall effort and cost involved in manufacturing and installing the staircase 3.

The mounting portion 11 has a central plate portion 11a that contacts the end face of the stringer 4, a first side plate portion 11b that is integrally formed with one end of the central plate portion 11a and contacts one side of the stringer 4, and a second side plate portion 11c that is integrally formed with the other end of the central plate portion 11a and contacts the other side of the stringer 4. The protruding plate portion 12 is integrally formed at a corner portion of the mounting portion 11 consisting of the central plate portion 11a and the first side plate portion 11b, and the surface of the protruding plate portion 12 and the surface of the central plate portion 11a are flush with each other, so that the surface of the mounting portion 11 from the central plate portion 11a to the protruding plate portion 12 can be seen as a single surface, which gives a good appearance.

The corrugated plate portion 13 has multiple mountain folds 14 and multiple valley folds 15, and the multiple mountain folds 14 are located on an extension of the overhang plate portion 12, so that the surface of the multiple mountain folds 14 from the overhang plate portion 12 to the corrugated plate portion 13 appears continuous, which gives a good appearance.

In addition, at least on the outer corner surface of the mountain fold 14 of the mountain fold 14 and the valley fold 15, a notch groove 14a is formed along the length direction, so that the notch groove 14a can be used as a guide when cutting off the corrugated plate portion 13 partially from the tip side in the projection direction. Furthermore, the notch groove 14a can also function as a guide when making cuts with a cutter or the like, so that the work of cutting off the corrugated plate portion 13 partially from the tip side in the projection direction can be easily performed, which contributes to improving workability.

In addition, the width dimension W1 of the surface on the outer corner of the mountain fold 14 is set to be longer than the width dimension W2 of the surface on the outer corner of the valley fold 15, so that a larger exposed surface can be secured compared to the valley fold 15, light can be more easily reflected, and the appearance can be improved in the same way as the central plate portion 11a and the protruding plate portion 12 of the mounting portion 11.

In addition, a holding portion 12a is integrally formed on the rear side of the protruding plate portion 12, into which a rod-shaped joint member J is inserted to hold the joint member J. Therefore, when connecting multiple gap covers 10 together, they can be connected by the joint member J inserted into the holding portion 12a to enhance integrity.
Furthermore, if multiple gap covers 10 can be connected by joint members J, the surfaces of the protruding plate portions 12 of multiple consecutive gap covers 10 are less likely to shift, resulting in a good appearance.
Furthermore, since the joint member J can be held by the protruding plate portion 12, which is a plate-shaped portion, it is possible to make the gap cover 10 have a core-like state, and the gap cover 10 can be reinforced.

When closing the gap S formed between the wall finishing material 2 and the stringer 4 with the gap cover 10, depending on the size of the gap S, either the corrugated plate portion 13 is partially cut off from the tip side in the projection direction and then the mounting portion 11 is attached to the edge portion 4a of the stringer 4, or the corrugated plate portion 13 is contracted while the mounting portion 11 is attached to the edge portion 4a of the stringer 4. This allows the gap S to be closed by simply changing the shape of the gap cover 10, without using unnecessary members other than the gap cover 10 as much as possible. As a result, even if the gap S between the stringer 4 and the wall finishing material 2 is not of a fixed size, it can be reliably closed with the gap cover 10, which is a single type of cover member, and this improves workability and reduces costs.

1 Staircase 2 Wall finishing material 3 Staircase 3a Landing 3b Frame plate 4 Slat 4a Edge portion 5 Step plate 6 Riser plate 10 Gap cover 11 Mounting portion 11a Central plate portion 11b First side plate portion 11c Second side plate portion 12 Projecting plate portion 12a Holding portion 13 Corrugated plate portion 14 Mountain fold portion 14a Notch groove 14b Notch groove 140 Wall side end portion 15 Valley fold portion 15a Notch groove S Gap J Joint member W1 Width dimension W2 Width dimension

Claims (4)

An attachment part attached to the edge part of the staircase beam;
A protruding plate portion protruding to one side from one side surface of the mounting portion;
A corrugated plate portion further protrudes to one side from the tip of the protruding plate portion in the protruding direction and is formed in a state in which mountain folds and valley folds are alternately repeated at a constant width.
A gap cover characterized in that the mounting portion, the protruding plate portion and the corrugated plate portion are integrally formed, and the same cross-sectional shape continues in the longitudinal direction. The corrugated plate portion has a plurality of mountain folds and a plurality of valley folds,
The gap cover according to claim 1 , wherein the plurality of mountain folds are positioned on an extension line of the protruding plate portion. The gap cover according to claim 1 or 2, characterized in that a holding part into which a rod-shaped joint member is inserted and which holds the joint member is integrally formed on the rear side of the protruding plate part. A method for closing a gap formed between a wall finishing material of a building and the slat beam by using the gap cover according to any one of claims 1 to 3 ,
Depending on the size of the gap,
A method for closing a gap, characterized in that the corrugated plate portion is partially cut off from the tip side in the protruding direction and then the attachment portion is attached to the end edge portion of the stringer, or the corrugated plate portion is contracted while the attachment portion is attached to the end edge portion of the stringer.

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