Technical Field
The present invention relates to a storage unit formed of a combination of basket-shaped blocks that store, for example, rainwater. Background Art
A structure including multiple basket-shaped structural components that are connected together using joint members and that allow a liquid such as rainwater to flow therein and thereout is thus far (see, for example, Patent Literature 1). This structure has no need of using bolts or welding for coupling the structural components, and thus can be constructed in a short period of time. Patent Literature 1 describes a case, as an example, where this structure is used to construct a road or a bridge. A combination of a large number of such structures also enables construction of a rainwater tank buried underground. Citation List Patent Literature

Summary of Invention Technical Problem [0004]
However, the above-described structure fails to be connected to another structure without using a large number of joint members. The structures thus form a complex joint structure. Particularly, firmly coupling the structures together in the horizontal direction is difficult. [0005]
When a rainwater tank constructed of the above-described structures is buried underground, the rainwater tank bears the horizontal earth pressure through the joint members. The rainwater tank thus has a problem of weak yield strength in the horizontal direction. Particularly, the horizontal earth pressure increases as the underground depth at which the rainwater tank is buried increases. Thus, a rainwater tank including the above-described structure is allowed to be buried only at a relatively small depth. Even a rainwater tank constructed by coupling one layer of the structures together in the horizontal direction is difficult to have enough yield strength in the horizontal direction to bear the horizontal earth pressure using the joint members.
The present invention aims to provide a storage unit that can be firmly connected with another storage unit and

that enables construction of rainwater tanks appropriate for various different depths. Solution to Problem [0006]
A storage unit of the present invention is a storage unit that includes a structure and a reinforcing frame. The structure includes a plurality of basket-shaped blocks that allow a liquid to flow therein and thereout. The reinforcing frame is coupled to another reinforcing frame in a horizontal direction by the structure. The basket-shaped blocks include a bottom portion, a frame-shaped flange portion, and a side wall. The flange portion is disposed at a periphery of an opening open to a side away from the bottom portion. The flange portion includes a plurality of projection portions projecting in a direction away from the bottom portion. The side wall obliquely extends outward from the bottom portions to the flange portion. The reinforcing frame has a shape compatible with the flange portion. The reinforcing frame includes at least four frame portions coupled together and each having recessed portions that receive the projection portions of the flange portion. To connect the structure including the basket-shaped blocks and the reinforcing frame to each other by inserting the projection portions to the recessed portions, the structure is connected to the

reinforcing frame and another reinforcing frame to extend across the two reinforcing frames so that a plurality of the reinforcing frames are coupled together in the horizontal direction. [0007]
Multiple storage units can be firmly coupled with each other by connecting each structure to two reinforcing frames to extend across the two reinforcing frames. Instead of using existing joint members, reinforcing frames are used to connect multiple structures together, so that the storage units can be connected together with a simple structure. This structure can enhance the yield strength of the storage units in the horizontal direction. This structure, not including joint members, can reduce the number of components constituting a rainwater tank and enables construction of a rainwater tank at low costs. [0008]
In the storage unit of the present invention, the basket-shaped blocks of the structure include at least one of a basket-shaped block including a protrusion on the bottom portion and a basket-shaped block including a recess on the bottom portion. When the basket-shaped blocks of the structure having the openings facing up are piled on the basket-shaped blocks of another structure having the opening

facing down, the protrusions are fitted into the recesses to vertically connect the basket-shaped blocks together. [0009]
By vertically connecting together the basket-shaped blocks each having the protrusion or the recess, the basket-shaped blocks can be vertically coupled together more firmly than in the case where the basket-shaped blocks are connected together using, for example, finely-structured projections of joint members.
In the storage unit of the present invention, the basket-shaped blocks of the structure include the basket-shaped block including the protrusion on the bottom portion and the basket-shaped block including the recess on the bottom portion.
By thus vertically connecting the basket-shaped blocks together using simply-structured protrusions and recesses formed on the bottom portions of the basket-shaped blocks, the basket-shaped blocks can be vertically coupled together more firmly. [0010]
In the storage unit of the present invention, the reinforcing frame is formed of a thermoplastic resin. Advantageous Effects of Invention [0011]

A storage unit of the present invention can be firmly coupled with another storage unit and enables construction of rainwater tanks appropriate for various difference depths. Brief Description of Drawings [0012]
[Fig. 1] Fig. 1 is a perspective view of a storage unit according to an embodiment viewed from above.
[Fig. 2] Fig. 2 is a perspective view of a structure constituting a storage unit according to an embodiment viewed from above.
[Fig. 3] Fig. 3 is a perspective view of a structure constituting a storage unit according to an embodiment viewed from below.
[Fig. 4] Fig. 4 is a side view of a structure constituting a storage unit according to an embodiment.
[Fig. 5] Fig. 5 is a plan view of a reinforcing frame constituting a storage unit according to an embodiment.
[Fig. 6] Fig. 6 is a perspective view of a reinforcing frame constituting a storage unit according to an embodiment viewed from above.
[Fig. 7] Fig. 7 is a schematic diagram illustrating the procedure of constructing a rainwater tank by piling storage units according to an embodiment.
[Fig. 8] Fig. 8 illustrates an example of a case where a

structure of a storage unit according to an embodiment is connected to two reinforcing frames so as to extend across the two reinforcing frames.
[Fig. 9] Fig. 9 is a schematic diagram of a rainwater tank constructed of layers of storage units according to an embodiment.
[Fig. 10] Fig. 10 illustrates structures according to an embodiment arranged numerically evenly in accordance with the shape of the reinforcing frames.
[Fig. 11] Fig. 11 is a schematic diagram of a rainwater tank constructed of layers of storage units according to an embodiment.
[Fig. 12] Fig. 12 is a schematic diagram of a process of constructing a rainwater tank by piling storage units according to an embodiment.
[Fig. 13] Fig. 13 is a side view of a structure constituting a storage unit according to a modification example of an embodiment.
[Fig. 14] Fig. 14 is a schematic diagram illustrating the state where top plates are mounted at the top of a rainwater tank constructed of layers of storage units according to an embodiment.
[Fig. 15] Fig. 15 is a schematic diagram illustrating the state where top plates cover the top of the rainwater

tank constructed of layers of storage units according to an
embodiment.
Description of Embodiments
[0013]
With reference to the drawings, a storage unit according to the embodiment is described below using a storage unit constituting a rainwater tank as an example. Fig. 1 is a perspective view of a storage unit according to an embodiment viewed from above. As illustrated in Fig. 1, a storage unit 1 includes structures 4, each including multiple basket-shaped blocks 2, and a reinforcing frame 6, including four square frame portions. [0014]
Fig. 2 is a perspective view of one structure 4 constituting the storage unit 1 according to the embodiment viewed from above. Fig. 3 is a perspective view of the structure 4 viewed from below. Fig. 4 is a side view of the structure 4. As illustrated in Figs. 2 to 4, the structure 4 is a member including two basket-shaped blocks 2 as a minimum unit and formed of injection-molded polypropylene. Each basket-shaped block 2 constituting the structure 4 has an opening 8 at the top and a bottom portion 10 at the bottom. The bottom portion 10 has a smaller area than the opening 8. The basket-shaped block 2 has side walls 11 on the sides.

The side walls 11 obliquely extend outward to the top. [0015]
A flange portion 12 including two coupled rectangular frames is disposed at the upper ends of the side walls 11 defining the openings 8. The flange portion 12 includes multiple projection portions 12a, which protrude in a direction away from the bottom portion 10, on the upper surface of the flange portion 12. The projection portions 12a surround the openings 8 at predetermined intervals. [0016]
The bottom portion 10 is a member that covers the bottom of the basket-shaped block 2 while allowing a liquid to flow thereinto. The bottom portion 10 has multiple through holes 10a that allow a liquid to flow thereinto. The bottom portion 10 has, at the center, a connection portion with which the bottom portions 10 of the storage units 1 piled one on another are vertically connected together. [0017]
As illustrated in Figs. 2 to 4, here, when a structure 4 constituting a storage unit 1 includes two basket-shaped blocks 2, one of the basket-shaped blocks 2 includes a protrusion lOe, which protrudes to the outside of the basket-shaped block 2 from the bottom portion 10 as a connection portion, and the other basket-shaped block 2 includes a

recess lOf, which is set back to the inner side of the basket-shaped block 2 from the bottom portion 10 as a connection portion. Each connection portion is supported by multiple ribs to be capable of being located at the center of the bottom portion 10. [0018]
Each side wall 11 is a wall having multiple through holes 11a into which a liquid can flow. The side walls 11 are located below four sides of the flange portion 12 and obliquely extend outward from the bottom portion 10 to the flange portion 12. Each side wall 11 includes multiple columns lib and furring strips lid. [0019]
Fig. 5 is a plan view of a reinforcing frame constituting the storage unit 1 according to an embodiment. Fig. 6 is a perspective view of the reinforcing frame viewed from above. As illustrated in Figs. 5 and 6, a reinforcing frame 6 has a structure including four coupled square frame portions 6a, and is formed of injection-molded polypropylene. Each frame portion 6a has a shape compatible with the flange portion 12. Two of four sides of each of four frame portions 6a are connected to two sides of another frame portion 6a. The four frame portions 6a form a square frame having a cross-shaped rib at the center.

On the top surface and the back surface of the reinforcing frame 6, recessed portions 6b, which receive the projection portions 12a (see Figs. 2 and 4), are disposed at predetermined intervals to surround the frame portions 6a. [0020]
Subsequently, a procedure of constructing a rainwater tank using the storage unit 1 according to the embodiment is described using a case of constructing a rainwater tank by piling the structures 4 into even-numbered layers as an example. To focus the following description on only the construction of a rainwater tank, the following description omits the description on the procedure of arranging accompanying components, such as laying of a bottom protection sheet or connection of water pipes. [0021]
As illustrated in Fig. 7(a), first, a worker places the basket-shaped blocks 2 on the bottom of dug ground so that the openings 8 face up. Here, before the basket-shaped blocks 2 are placed on the ground, the basket-shaped blocks 2 that are to be placed at the lowermost layer have their protrusions lOe at the bottom portions 10 cut off. Thus, the bottom portions 10 of the basket-shaped blocks 2 placed at the lowermost layer are leveled with each other, and the flange portions 12 are leveled with each other.

[0022]
Subsequently, the worker aligns the positions of the recessed portions 6b (see Figs. 5 and 6) of the reinforcing frames 6 with the positions of the projection portions 12a (see Figs. 2 and 4) of the flange portions 12 of the basket-shaped blocks 2, and places the reinforcing frames 6 on the basket-shaped blocks 2. Thus, the projection portions 12a are fitted into the recessed portions 6b, so that the reinforcing frames 6 are fixed onto the structures 4. [0023]
Subsequently, as illustrated in Fig. 7(b), the worker places the basket-shaped blocks 2 on the reinforcing frames 6 so that the openings 8 face down. To place the basket-shaped blocks 2 on the reinforcing frames 6, here, for example, the worker places each structure 4 so that the structure 4 extends across two reinforcing frames 6, as illustrated in Fig. 8. Thus, the multiple reinforcing frames 6 are connected together in the horizontal direction. [0024]
Subsequently, as illustrated in Fig. 7(c), the worker places the basket-shaped blocks 2 having the openings 8 facing up on the basket-shaped blocks 2 mounted on the reinforcing frames 6 and having the openings 8 facing down. In this case, the worker piles the basket-shaped blocks 2

each having the recess lOf at the bottom portion 10 on the basket-shaped blocks 2 each having the protrusion lOe at the bottom portion 10, and then piles the basket-shaped blocks 2 each having the protrusion lOe at the bottom portion 10 on the basket-shaped blocks 2 each having the recess lOf at the bottom portion 10. Thus, the basket-shaped blocks 2 having their openings 8 facing away from each other and having their protrusions lOe fitted into their recesses lOf can be vertically piled one on another without being misaligned with each other in the horizontal direction. [0025]
By repeating the same operation, a rainwater tank formed of multiple layers of the basket-shaped blocks 2 can be constructed, as illustrated in Fig. 9. Before being placed on other basket-shaped blocks 2, the basket-shaped blocks 2 located at the top layer and having the protrusions lOe at the bottom portions 10 may have their protrusions lOe cut off. Thus, the bottom portions 10 of the basket-shaped blocks 2 located at the top layer can be leveled with each other, and the flange portions 12 can be leveled with each other.
In this embodiment of the invention, multiple storage units 1 can be firmly coupled with each other by placing the basket-shaped blocks 2 on two reinforcing frames 6 so that the basket-shaped blocks 2 extend across the two reinforcing

frames 6 to horizontally connect the storage units 1 to each other. Instead of using existing joint members, the reinforcing frames 6 are thus used to connect multiple structures 4 together, so that the storage units 1 can be connected together with a simple structure. This structure can enhance the yield strength of the storage units 1 in the horizontal direction. This structure, not including joint members, can reduce the number of components constituting a rainwater tank and enables construction of a rainwater tank at low costs. [0026]
The reinforcing frame 6 has a structure including four coupled sguare frame portions 6a, and each structure 4 includes two basket-shaped blocks 2. Thus, the structures 4 each placed on two reinforcing frames 6 to extend across the two reinforcing frames 6 to couple the reinforcing frames 6 together are arranged to numerically correspond to the reinforcing frames 6. For example, as illustrated in Figs. 10(a) and 10(b), the structures 4 at both ends of the rainwater tank are arranged perpendicularly to the direction in which the other structures 4 are arranged, so that the structures 4 can be arranged in accordance with the shape of the reinforcing frames 6. [0027]

This embodiment of the invention enables simple coupling of the storage units 1 together without using joint members. Thus, the storage units 1 can be coupled together to form a complex shape, as illustrated in, for example, Fig. 11. [0028]
The above-described embodiment is described using a case where the structures 4 are piled in even-numbered layers to construct a rainwater tank as an example. However, a rainwater tank can be constructed by piling the structures 4 in odd-numbered layers. In this case, first, a worker places the reinforcing frames 6 on the bottom of the dug ground, as illustrated in Fig. 12(a), and then places basket-shaped blocks 2 on the reinforcing frames 6 so that the openings 8 face down. [0029]
Thereafter, as in the case of piling the structures 4 in even-numbered layers, the reinforcing frames 6 and the structures 4 are alternately piled one on another in a repeated manner. Thus, a rainwater tank having a predetermined number of layers is complete, as illustrated in Fig. 12(b). [0030]
In the present invention, the reinforcing frames 6 bear the horizontal earth pressure instead of joint members. Thus,

a rainwater tank can be formed of the storage units 1 of a single layer, as illustrated in Fig. 12(a). Thus, the rainwater tank can be buried underground at even a small depth. The storage unit 1 includes the reinforcing frames 6 having high yield strength in the horizontal direction, and thus a rainwater tank can be buried on the bottom of the deeply dug ground. By appropriately piling the structures 4 in even-numbered layers or odd-numbered layers, rainwater tanks appropriate for various different depths can be constructed.
In the above-described embodiment, the basket-shaped blocks 2 included in one structure 4 may include the connection portions of the same type. Specifically, the above-described embodiment may include a structure 4 only including the basket-shaped blocks 2 including the protrusions lOe, as illustrated in Fig. 13(a), and a structure 4 only including the basket-shaped blocks 2 including the recesses lOf, as illustrated in Fig. 13(b). Also in this case, a rainwater tank is constructed in the same procedure as described with reference to Figs. 7 to 9, by repeatedly piling the basket-shaped blocks 2 each including the recess lOf at the bottom portion 10 on the basket-shaped blocks 2 each including the protrusion lOe at the bottom portion 10, or by piling the basket-shaped blocks

2 each including the protrusion lOe at the bottom portion 10 on the basket-shaped blocks 2 each including the recess lOf at the bottom portion 10.
By arranging only the structures 4 including the basket-shaped blocks 2 each including the recess lOf in the lowermost layer or uppermost layer, the flange portions 12 may be easily leveled with each other and the bottom portions 10 of the structures 4 arranged in the lowermost layer or uppermost layer may be easily leveled with each other without cutting off the protrusions lOe.
Also in the case where a rainwater tank is constructed of the structures 4 including only the basket-shaped blocks 2 including the protrusions lOe and the structures 4 including only the basket-shaped blocks 2 including the recesses lOf, the protrusions lOe are fitted into the recesses lOf, so that the basket-shaped blocks 2 can be vertically piled one on another without being misaligned from each other in the horizontal direction. [0031]
In the above-described embodiment, the structures 4 and the reinforcing frames 6 may be formed of a thermoplastic resin other than polypropylene. The structures 4 and the reinforcing frames 6 may be formed by a method other than injection molding.

[0032]
In the above-described embodiment, each structure 4 does not necessarily have to be constituted of two basket-shaped blocks 2. For example, each structure 4 may have a L shape formed of three basket-shaped blocks 2. Alternatively, each structure 4 may be formed of four basket-shaped blocks 2 so that the basket-shaped blocks 2 correspond to the frame portions 6a of the reinforcing frame 6. [0033]
The above-described embodiment describes a case where a rainwater tank can be constructed without using joint members. However, a rainwater tank can be constructed using joint members. A stronger rainwater tank can be constructed using joint members in addition to the reinforcing frames 6.
In the above-described embodiment, to construct a rainwater tank, as illustrated in Fig. 14, top plates 14 may be attached to the structures 4 of the uppermost layer constituting the rainwater tank. Here, each top plate 14 is a member having two openings 14a and having a rectangular shape when viewed in a plan. Each opening 14a has approximately the same size as the bottom portion 10 of each basket-shaped block 2. After the protrusions lOe are cut off, the top plates 14 are attached to the structures 4 of the uppermost layer constituting the rainwater tank such that the

bottom portions 10 are fitted into the openings. Thus, the rainwater tank has a flat upper surface, as illustrated in Fig. 15. [0034]
In the above-described embodiment, each reinforcing frame 6 may have a shape formed of a combination of thin components. Specifically, the reinforcing frame 6 may have multiple recessed portions defined by thin side walls and a thin bottom surface, and ribs may be formed in the recessed portions to appropriately reinforce the yield strength of the reinforcing frame 6. [0035]
This structure can form each reinforcing frame 6 into a light-weight high-strength member, particularly having enhanced yield strength in the horizontal direction. In this case, the recessed portions 6b may be formed of recessed portions located at positions corresponding to the positions of the projection portions 12a when the reinforcing frame 6 is placed on the flange portion 12. [0036]
Similarly, each flange portion 12 may have a shape formed of a combination of thin members. Specifically, the flange portion 12 may have multiple recessed portions defined by thin side walls and a thin bottom surface, and ribs may be

formed in the recessed portions to appropriately reinforce
the yield strength of the flange portion 12.
[0037]
In the above-described embodiment, a case where each recessed portion 6b in the reinforcing frame 6 has a rectangular cross section is described as an example. However, the recessed portion 6b may have a circular cross section.
Reference Signs List [0038]
1 storage unit
2 basket-shaped block 4 structure
6 reinforcing frame 6a frame portion 6b recessed portion 8 opening
10 bottom portion 10a through hole lOe protrusion lOf recess
11 side wall 11a through hole lib column

lid furring strip
12 flange portion
12a projection portion
14 top plate
14a opening

WE CLAIM:
[Claim 1]
A storage unit, comprising a structure and a reinforcing frame, the structure including a plurality of basket-shaped blocks that allow a liquid to flow therein and thereout, the reinforcing frame being coupled to another reinforcing frame in a horizontal direction by the structure,
wherein the basket-shaped blocks include a bottom portion,
a frame-shaped flange portion disposed at a periphery of an opening open to a side away from the bottom portion, the flange portion including a plurality of projection portions projecting in a direction away from the bottom portion, and
a side wall that obliquely extends outward from the bottom portion to the flange portion,
wherein the reinforcing frame has a shape compatible with the flange portion, and the reinforcing frame includes at least four frame portions coupled together and each having recessed portions that receive the projection portions of the flange portion, and
wherein, to connect the structure including the basket-shaped blocks and the reinforcing frame to each other by inserting the projection portions to the recessed portions,

the structure is connected to the reinforcing frame and another reinforcing frame to extend across the two reinforcing frames so that a plurality of the reinforcing frames are coupled together in the horizontal direction. [Claim 2]
The storage unit according to Claim 1,
wherein the basket-shaped blocks of the structure include at least one of a basket-shaped block including a protrusion on the bottom portion and a basket-shaped block including a recess on the bottom portion, and
wherein, when the basket-shaped blocks of the structure having the openings facing up are piled on the basket-shaped blocks of another structure having the opening facing down, the protrusions are fitted into the recesses to vertically connect the basket-shaped blocks together. [Claim 3]
The storage unit according to Claim 2, wherein the basket-shaped blocks of the structure include the basket-shaped block including the protrusion on the bottom portion and the basket-shaped block including the recess on the bottom portion. [Claim 4]
The storage unit according to Claim 1 or 2, wherein the reinforcing frame is formed of a thermoplastic resin.