JP2022019167A - Extendable water stopping structure provided in joint gap between bridge girders - Google Patents

Abstract

To provide an extendable water stopping structure provided in joint gaps between bridge girders that can properly accommodate changes in joint gaps and sufficiently prevents rain-water from falling.SOLUTION: An extendable water stopping structure 1 is composed of rectangular first-fourth metal plates 5, 6, 7, 8 and an extendable body 10. The first-fourth metal plates are bent by a mountain fold line parallel to the long side to form vertical plate parts 5a, 6a, ... and horizontal plate parts 5b, 6b, .... While the first and second metal plates 5, 6 have their respective vertical plate parts bonded to one and the other end surfaces of a slab 2, the horizontal plate parts are slidably stacked with predetermined overlapping space so that the horizontal plate parts face each other. The vertical plate parts of the third and fourth metal plates 7, 8, are bonded to the vertical plate parts of the first and second metal plates 7, 8, and the horizontal plate parts are slidably stacked with predetermined overlapping space. An extendable body 10 is provided in an internal space surrounded by the horizontal plate parts of the first and second metal plates, the vertical plate parts of the first and second metal plates, and the horizontal plate parts of the third and fourth metal plates.SELECTED DRAWING: Figure 1

Description

The present invention relates to a telescopic waterproof structure or a telescopic joint structure provided at a connection portion between bridge girders in a bridge or an elevated road.

Bridges and elevated roads are built on multiple piers. In other words, a superstructure, that is, a bridge girder consisting of a girder and a deck, is erected between two adjacent predetermined piers, and a bridge girder is also provided between the next two adjacent piers. Multiple bridge girders are connected to. A paved road made of asphalt mixture is laid on these bridge girders. By the way, a predetermined gap, that is, a play space is formed at these connecting portions between adjacent floor slabs. This is to prevent the expansion and contraction of the bridge girder due to the thermal expansion of temperature changes, and to mitigate the effects of earthquakes and tremors. A predetermined expansion / contraction device, that is, a joint structure is provided at the connection portion between the bridge girders so that the bridge girders are smoothly connected to each other and the expansion / contraction is allowed. For example, finger joints made of steel, rubber joints made of rubber members, buried joints made of elastic pavement material, and the like are well known. Under these telescopic devices, a predetermined telescopic water blocking structure is provided so that rainwater that has fallen on the road does not fall downward. For the stretchable waterproof structure, a waterproof material made of an elastic material such as urethane foam is adopted and inserted in the play space. Since such a water blocking material is pressed and inserted into the play space, it can be in close contact with the floor slab constituting the bridge girder to prevent rainwater from falling.

Japanese Patent Application Laid-Open No. 2003-138511

Patent Document 1 describes a joint structure or a joint structure that allows a large variation in play. As shown in FIG. 3, the joint structure 50 described in Patent Document 1 is provided in the space between the floor slabs 51 and 52. The joint structure 50 is composed of a pair of rubber members having a predetermined shape, that is, a first joint half body 54 and a second joint half body 55. Both the first joint half body 54 and the second joint half body 55 are formed to the length of the road width of the bridge girder, and are formed in a comb shape with a predetermined interval, that is, the plate portions, that is, the protrusions 58, 59. , ... are formed. Then, between the projecting pieces 58, 58, ... Of the first joint half body 54, the projecting pieces 59, 59, ... Of the second joint half body 55 are slidably inserted. Therefore, when the play space of the floor slabs 51 and 52 fluctuates, the first and second joint halves 54 and 55 slide with each other. In FIG. 3, an elastic paving material 60 is paved on the joint structure 50.

The fall of rainwater between bridge girders can be prevented by a conventional waterproof material made of an elastic material such as urethane foam, or by the joint structure 50 described in Patent Document 1. However, there are some problems to be solved. For example, with the conventional waterproof material, the amount of expansion and contraction that can be absorbed is not sufficiently large, so that a gap may be formed when the play space increases or decreases depending on the season. Further, when a heavy vehicle passes through the bridge, the bridge vibrates and the size of the play space changes in a short time, but the elastic material such as urethane foam alone cannot sufficiently cope with the change in the play space in a short time. Furthermore, with regard to the water blocking material made of a conventional elastic material, when the size of the play space changes and the dimension in the width direction changes, it inevitably expands or contracts in the vertical direction. Then, when the pavement having elasticity is constructed on the waterproof material, there is a problem that the pavement is depressed or protrudes. On the other hand, in the joint structure 50 described in Patent Document 1, since the first and second joint halves 54 and 55 slide with each other to change the width, the interval between play changes. The amount of expansion and contraction that can be absorbed is large, and even if a heavy vehicle runs and the size of the play space changes in a short time, this can be absorbed smoothly. Furthermore, even if the size of the play space changes and the dimension in the width direction changes, there is an excellent feature that expansion and contraction in the vertical direction is relatively small. However, even in the joint structure 50 described in Patent Document 1, a slight change in volume in the vertical direction occurs. When the paving material 60 having elasticity is paved on the joint structure 50, a dent may occur as shown by reference numeral 61 in FIG. 3, although the change in the size of the play space causes a slight dent. , As indicated by reference numeral 62, swelling may occur. Furthermore, there is room for improvement in the water blocking effect. In the joint structure 50, the first and second joint halves 54 and 55 are inserted into each other with the projecting pieces 58, 59, ..., Which prevents rainwater from falling to some extent, but the projecting pieces 58. , 59, ... Rainwater that falls through the gaps between them cannot be completely prevented. If the gaps between the projecting pieces 58, 59, ... Are made as small as possible, it may be possible to substantially completely prevent the rainwater from falling. However, if the gaps are almost eliminated, if the protrusions 58, 59, ... Are expanded depending on the season, the slide may be hindered and the joint structure 50 may not be able to properly absorb the change in the width of the play. That is, there is a problem that the gaps between the projecting pieces 58, 59, ... Must be adjusted so that the rainwater can be sufficiently prevented from falling and the slide is surely guaranteed.

An object of the present invention is to provide a telescopic waterproof structure provided in a gap between bridge girders, which solves the above-mentioned problems. Specifically, the present invention provides a gap with almost no change in volume in the vertical direction. It is an object of the present invention to provide a telescopic waterproof structure provided between the gaps of bridge girders of bridges and elevated roads, which can appropriately absorb changes in size and sufficiently prevent rainwater from falling.

In order to achieve the above object, the present invention comprises a stretchable waterproof structure composed of rectangular first to fourth metal plates having long long sides and a predetermined stretchable body that allows stretchability. The first to fourth metal plates are bent by one mountain fold line parallel to the long side so as to have a vertical vertical plate portion and a horizontal horizontal plate portion. The first and second metal plates have their respective vertical plate portions bonded to the end faces of one and the other floor slab, but slide with a predetermined stacking allowance so that the horizontal plate portions face each other. It is freely stacked. The third and fourth metal plates are slid with a predetermined stacking allowance so that the vertical plate portions of each are adhered to the vertical plate portions of the first and second metal plates, and the horizontal plate portions face each other. It is freely stacked. An elastic body is provided in the internal space surrounded by the horizontal plate portion of the first and second metal plates, the vertical plate portion of the first and second metal plates, and the horizontal plate portion of the third and fourth metal plates.

Thus, the invention of claim 1 is a gap between the slabs of adjacent bridge girders of a bridge or elevated road consisting of a plurality of bridge girders connected to each other in order to achieve the above object. It is a telescopic waterproof structure that expands and contracts according to a change in the size of the play space and prevents rainwater flowing into the play space from falling, and the telescopic water stop structure is long. It is composed of a rectangular first to fourth metal plate with long sides and a predetermined stretchable body that allows expansion and contraction, and each of the first to fourth metal plates is bent by one mountain fold line parallel to the long side. As a result, a vertical vertical plate portion and a horizontal horizontal plate portion are formed, and in the first and second metal plates, the respective vertical plate portions are the end faces of one floor slab and the other floor slab. The horizontal plate portions face each other and are slidably overlapped with each other with a predetermined stacking allowance, and the third and fourth metal plates are the first and second metal plates. Inside, each of the vertical plate portions is adhered to the respective vertical plate portions of the first and second metal plates, and the respective horizontal plate portions face each other and are slidably overlapped with a predetermined stacking allowance. The stretchable body includes the horizontal plate portion of the first and second metal plates, the vertical plate portion of the first and second metal plates, and the horizontal plate portion of the third and fourth metal plates. It is configured as a telescopic waterproof structure characterized by being placed in a rectangular internal space consisting of.
According to the second aspect of the present invention, in the telescopic waterproof structure according to the first aspect, the horizontal plate portion of each of the first and second metal plates has a slightly sharp angle with respect to the vertical plate portion. The third and fourth metal plates are bent so that each of the horizontal plate portions has a slightly blunt angle with respect to the vertical plate portion, whereby the metal plates are placed in the internal space. The stretchable body is pressed downward from the horizontal plate portion of the first and second metal plates, and is pushed upward from the horizontal plate portion of the third and fourth metal plates. It is configured as a characteristic telescopic waterproof structure.
The invention according to claim 3 is the telescopic waterproof structure according to claim 1 or 2, wherein the stretchable body is composed of a plurality of slide plates having a predetermined thickness made of rubber or a hard foamed resin. Has a rectangular shape on the upper surface, and its short side is shorter than the horizontal width of the internal space, so that approximately half of the slide plates are spaced up and down at intervals substantially equal to the plate thickness of the slide plates. It is provided horizontally, and the end face corresponding to each long side is adhered to the vertical plate portion of the first metal plate, and the remaining slide plates are inserted between the slide plates of about half of the slide plates. The end face corresponding to each long side is adhered to the vertical plate portion of the second metal plate, and is configured as a stretchable waterproof structure.
The invention according to claim 4 is the stretchable water-stopping structure according to claim 1 or 2, wherein the stretchable body is made of a rectangular parallelepiped foamed resin having elasticity. Will be done.

As described above, the present invention is provided in the gap between the decks of the adjacent bridge girders of the bridge or the elevated road consisting of a plurality of bridge girders connected to each other, and the size of the gap is large. It is intended for telescopic waterproof structures that expand and contract according to changes and prevent rainwater from falling during play. According to the present invention, the stretchable waterproof structure is composed of rectangular first to fourth metal plates having long long sides and a predetermined stretchable body that allows stretch. The first to fourth metal plates are each bent by one mountain fold line parallel to the long side, whereby a vertical vertical plate portion and a horizontal horizontal plate portion are formed, and the first and second metal plates are formed. In the metal plate, each vertical plate portion is adhered to each end face of one floor slab and the other floor slab, and the horizontal plate portions face each other and slide freely with a predetermined stacking allowance. In the third and fourth metal plates, the respective vertical plate portions are adhered to the respective vertical plate portions of the first and second metal plates inside the first and second metal plates, and the respective horizontal plates are bonded to each other. The portions face each other and are slidably overlapped with a predetermined stacking allowance, and the stretchable body includes the horizontal plate portion of the first and second metal plates, the vertical plate portion of the first and second metal plates, and the third. It is housed in a rectangular internal space composed of a horizontal plate portion of the metal plate of No. 4. Therefore, in the telescopic waterproof structure according to the present invention, the distance between the first and second metal plates and the distance between the third and fourth metal plates changes, and the distance between the decks, that is, the size of the play space changes. Is designed to absorb. Since the telescopic waterproof structure of the present invention is a horizontal plate portion of the first and second metal plates whose uppermost surfaces are slid with each other, even if the size of the play space changes and the whole expands and contracts. , There is no vertical volume change. As a result, even if an elastic pavement material is provided on the stretchable waterproof structure, the pavement material does not have irregularities. In addition, since the uppermost surface of the telescopic waterproof structure is the horizontal plate portion of the first and second metal plates, most of the rainwater is blocked at this portion to prevent the rainwater from falling downward. .. According to another invention, the first and second metal plates are bent so that the respective horizontal plate portions are slightly sharp with respect to the vertical plate portion, and the third and fourth metal plates are the respective horizontal plate portions. The portion is bent so as to be slightly blunt with respect to the vertical plate portion, whereby the stretchable body contained in the internal space is pressed downward from the horizontal plate portion of the first and second metal plates. At the same time, it is pushed upward from the horizontal plate portion of the third and fourth metal plates. Therefore, a predetermined pressure is applied to the stretchable body from the vertical direction to stabilize the shape of the stretchable body, and it is guaranteed that the stretchable waterproof structure is properly maintained for a long period of time. According to still another invention, the stretchable body is composed of a plurality of slide plates having a predetermined thickness made of rubber or hard foamed resin, and the slide plates have a rectangular upper surface shape, and the short side thereof is larger than the horizontal width of the internal space. It is shortened, and about half of the slide plates are horizontally provided so as to be vertically spaced from each other at a distance approximately equal to the plate thickness of the slide plates, and the end faces corresponding to the long sides of each are vertical to the first metal plate. It is adhered to the plate portion, the remaining slide plates are each inserted between approximately half of the slide plates, and the end faces corresponding to the long sides of each are adhered to the vertical plate portion of the second metal plate. .. Therefore, when the size of the play space changes and the distance between the first and second metal plates changes, it is only necessary to change the size of the stacking allowance between the plurality of slide plates. In other words, the change in the size of the play can be absorbed only by sliding the slide plates together. Then, even if a heavy vehicle travels on the bridge and the bridge girder vibrates and the size of the play space changes in a short time, it can be easily absorbed. In addition, the change in the size of the play space that can be absorbed can be taken sufficiently large. According to another invention, the stretchable body is made of a rectangular parallelepiped foamed resin having elasticity. Then, the stretchable body can be made of inexpensive urethane foam or the like, and the stretchable waterproof structure can be provided at low cost.

(A) is a perspective view showing a bridge girder adjacent to a bridge or an elevated road, a finger joint provided between the gaps of each bridge girder, and a telescopic waterproof structure according to an embodiment of the present invention. (B) is a front sectional view of the telescopic waterproof structure according to the embodiment of the present invention. It is a figure which shows the telescopic waterproof structure which concerns on other embodiment of this invention, (A) is the stretchable waterproof structure which concerns on 2nd Embodiment, and (B) is 3rd Embodiment. It is a front sectional view which shows the expansion and contraction water stop structure which concerns on the form of. It is a figure which shows the conventional example, and is the front sectional view of the joint structure provided in the space between adjacent bridge girders of a bridge or an elevated road.

Hereinafter, embodiments of the present invention will be described. As shown in FIG. 1A, the telescopic waterproof structure 1 according to the present embodiment of the present invention constitutes a bridge girder in a gap between adjacent bridge girders of a bridge or an elevated road, that is, a bridge girder. It is provided between the play of each of the floor slabs 2 and 2. In the present embodiment, an expansion / contraction device 3 made of a steel finger joint is provided on the floor slabs 2 and 2, and the expansion / contraction waterproof structure 1 according to the present embodiment is under the expansion / contraction device 3. It is provided so as to block rainwater entering from the expansion / contraction device 3 to prevent the rainwater from falling and to absorb a change in the size of the play space.

As shown in FIGS. 1A and 1B, the telescopic waterproof structure 1 according to the present embodiment has the first to fourth metal plates 5, 6, 7, and 8 and predetermined ones. It is composed of a stretchable body 10. The first to fourth metal plates 5, 6, 7, and 8 are made of stainless steel having a predetermined plate thickness and are formed of a rectangular plate that is long in the width direction of the bridge. The first to fourth metal plates 5, 6, 7, and 8 are bent at substantially right angles by mountain fold lines parallel to the long sides of the rectangle, respectively, and are horizontal with the vertical vertical plate portions 5a, 6a, 7a, and 8a. Horizontal plate portions 5b, 6b, 7b, 8b are formed. The first metal plate 5 and the second metal plate 6 are arranged so that the horizontal plate portions 5b and 6b face each other, and the horizontal plate portions 5b and 6b are slidably overlapped with a predetermined stacking allowance. Each of these vertical plate portions 5a and 6a is adhered to the end faces of the floor slabs 2 and 2. The third and fourth metal plates 7 and 8 are provided inside the first and second metal plates 5 and 6, and the vertical plate portion 7a of the third metal plate 7 is the vertical plate portion of the first metal plate 5. The vertical plate portion 8a of the fourth metal plate 8 and the vertical plate portion 8a of the fourth metal plate 8 are fixed to the vertical plate portion 6a of the second metal plate 6 by welding or the like, respectively. The horizontal plate portions 7b and 8b of the third and fourth metal plates 7 and 8 face each other and are slidably overlapped with a predetermined stacking allowance. The horizontal plate portions 5b and 6b of the first and second metal plates 5 and 6 and the horizontal plate portions 7b and 8b of the third and fourth metal plates 7 and 8 are vertically separated from each other, whereby the first and second metal plates 5b and 6b are separated from each other. The horizontal plate portions 5b, 6b of the metal plates 5 and 6 and the vertical plate portions 5a and 6a of the first and second metal plates 5 and 6 and the horizontal plate portions 7b and 8b of the third and fourth metal plates 7 and 8. A rectangular body-shaped internal space is formed in the above space, and the stretchable body 10 is inserted in this internal space.

In the present embodiment, the stretchable body 10 is composed of a plurality of slide plates 12, 13, .... The slide plates 12, 13, ... Can be formed of a hard foamed resin, that is, a hard foamed resin, but in the present embodiment, they are made of synthetic rubber such as urethane or rubber such as natural rubber. The slide plates 12, 13, ... Have a predetermined thickness and a rectangular top surface shape and are formed long in the width direction of the bridge. The short sides of the rectangle are from the first to fourth metal plates 5, 6, 7, and 8. It is shorter than the width of the internal space. In the present embodiment, the slide plates 12, 13, ... Are composed of 6 to 7 slide plates, and about half of the slide plates 12, 12, ... Are on the vertical plate portion 5a of the first metal plate 5, and the remaining slide plates 13 , 13, ... Are fixed to the vertical plate portion 6a of the second metal plate 6, respectively. More specifically, about half of the former slide plates 12, 12, ... Are arranged horizontally at intervals of the plate thickness of the slide plates 12 in the vertical direction, and their respective end faces are the first metal plate 5. It is fixed to the vertical plate portion 5a of. The remaining slide plates 13, 13, ... Of the latter are inserted between the slide plates 12, 12, ... Of the former, and their respective end faces are fixed to the vertical plate portion 6a of the second metal plate 6. Therefore, when the size of the play space between the floor slabs 2 and 2 changes and the distance between the first and third metal plates 5 and 7 and the second and fourth metal plates 6 and 8 changes, the slide plates 12 and 13 , ... slide each other. That is, the stretchable body 10 expands and contracts. In the telescopic body 10 made of such slide plates 12, 13, ..., The upper portion thereof is the horizontal plate portions 5b, 6b of the first and second metal plates 5, 6 and the lower portion thereof is the third and fourth metal plates. It is in close contact with the horizontal plate portions 7b and 8b of 7 and 8, respectively.

By the way, it was explained that the first to fourth metal plates 5, 6, 7, and 8 are all bent at a substantially right angle, but the first and second metal plates 5, 6 are slightly sharper than the right angle, and The third and fourth metal plates 7 and 8 are bent at an obtuse angle slightly larger than a right angle. Then, when the stretchable waterproof structure 1 is assembled from the first to fourth metal plates 5, 6, 7, 8 and the stretchable body 10, the first to fourth metal plates 5, 6, 7, and 8 are formed. It is formed at right angles against each elasticity. At this time, as shown in FIG. 1 (B), the stretchable body 10 has the first and second metal plates 5 and 6 downward from the horizontal plate portions 5b and 6b, and the third and fourth metal plates 5b and 6b. A force acts upward from the horizontal plate portions 7b, 8b of the metal plates 7, 8, and the adhesion between the slide plates 12, 13, ... Is enhanced. Although a force acts downward due to gravity on the slide plates 12, 13, ..., Since the magnitude of the urging force due to the elasticity of the third and fourth metal plates 7, 8 is large, these are appropriately supported. Will be done.

The telescopic waterproof structure 1 according to the present embodiment may only be adhered to the end faces of the floor slabs 2 and 2, but if necessary, springs 15, 15, ... A character-shaped gutter 16 may be provided. In this case, if the spring positioning members 18 and 18 and the U-shaped gutter positioning members 19 and 19 are provided in advance inside the vertical plate portions 7a and 8a of the third and fourth metal plates 7 and 8, the construction can be performed. It will be easier.

The telescopic waterproof structure 1 according to the embodiment of the present invention can be deformed in various ways. FIG. 2A shows the stretchable waterproof structure 1'according to the second embodiment, but in this embodiment, the stretchable body 10'has elasticity such as urethane foam. It is made of foamed resin. Therefore, even if the size of the play space fluctuates, the fluctuation can be appropriately absorbed. In FIG. 2B, the telescopic waterproof structure 1 ″ according to the third embodiment is shown, but in this embodiment, the telescopic body 10 ″ has springs 20, 20, ... It is equipped with. Specifically, the stretchable body 10'' is composed of slide plates 12', 13', ... Like the stretchable body 10 in the first embodiment, but the slide plates 12', 13', respectively. There are small-diameter horizontal holes in the end faces of the holes, and springs 20, 20, ... Are inserted in each of these holes. These springs 20, 20, ... Are in contact with the vertical plate portions 5a and 6a of the first and second metal plates 5 and 6, respectively, by a predetermined spring urging. By these springs 20, 20, ..., The telescopic waterproof structure 1 ″ is urged in the direction of being pushed open, and is firmly attached to the play space.

The telescopic waterproof structure 1 according to the present embodiment can be further deformed, and the number of slide plates 12, 13, ... May be about 4 or 8 or more. Further, it was explained that the slide plates 12, 13, ... As if they were flat plates. However, in the portion of the bridge corresponding to the roadside zone, a wall for preventing the vehicle from falling, that is, a rising edge is formed. The ends of the slide plates 12, 13, ... May be curved upward to fit the rise so that rainwater does not fall from the boundary between the road and the rise. Then, it is possible to prevent rainwater from falling from the boundary between the road and the rising edge.

1 Telescopic waterproof structure 2 Floor slab 3 Telescopic device 5 First metal plate 5a Vertical plate part 5b Water plate part 6 Second metal plate 6a Vertical plate part 6b Water plate part 7 Third metal plate 7a Vertical plate part 7b Water plate part 8 4th metal plate 8a Vertical plate part 8b Water plate part 10 Telescopic body 12 Slide plate 13 Slide plate 15 Spring 16 U-shaped gutter

Claims (4)

A gap between bridges or elevated roads consisting of a plurality of bridge girders connected to each other, which is a gap between the decks of adjacent bridge girders, expands and contracts according to a change in the size of the gap, and the gap It is a telescopic waterproof structure that prevents rainwater from falling into the water.
The telescopic waterproof structure is composed of rectangular first to fourth metal plates having long sides and a predetermined stretchable body that allows stretch.
The first to fourth metal plates are each bent by one mountain fold line parallel to the long side, whereby a vertical vertical plate portion and a horizontal horizontal plate portion are formed.
The first and second metal plates have their respective vertical plate portions adhered to the end faces of one floor slab and the other floor slab, and the horizontal plate portions face each other. It is slidably overlapped with a predetermined stacking allowance,
In the third and fourth metal plates, the vertical plate portions thereof are adhered to the vertical plate portions of the first and second metal plates inside the first and second metal plates, and the respective vertical plate portions are adhered to each other. The water plate parts face each other and are slidably overlapped with a predetermined stacking allowance.
The stretchable body is composed of the horizontal plate portion of the first and second metal plates, the vertical plate portion of the first and second metal plates, and the horizontal plate portion of the third and fourth metal plates. A telescopic waterproof structure characterized by being placed in a rectangular internal space. In the telescopic waterproof structure according to claim 1, the first and second metal plates are bent so that each of the horizontal plate portions is slightly sharp with respect to the vertical plate portion, and the third metal plate portion is bent. In the metal plate of 4, each of the horizontal plate portions is bent so as to have a slightly blunt angle with respect to the vertical plate portion, whereby the stretchable body inserted in the internal space is the first. A telescopic waterproof structure characterized in that the metal plate of No. 2 is pressed downward from the horizontal plate portion and is pushed upward from the horizontal plate portion of the third and fourth metal plates. In the telescopic waterproof structure according to claim 1 or 2, the stretchable body is composed of a plurality of slide plates having a predetermined plate thickness made of rubber or a hard foamed resin, and the slide plates have a rectangular upper surface shape. Its short side is shorter than the width of the internal space,
Approximately half of the slide plates are horizontally provided so as to be vertically spaced from each other at a distance substantially equal to the plate thickness of the slide plates, and the end faces corresponding to the long sides of the respective slide plates are the vertical plates of the first metal plate. It is glued to the part,
The remaining slide plates are each inserted between the slide plates of about half of the slide plates, and the end faces corresponding to the long sides of the slide plates are bonded to the vertical plate portion of the second metal plate. Telescopic waterproof structure. The telescopic waterproof structure according to claim 1 or 2, wherein the stretchable body is made of a rectangular parallelepiped foamed resin having elasticity.

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