JPH11313545A - Extendable fence - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an extendable fence capable of performing the position change of plants easily without harming a harmonization with the plants and a one unit feeling as a garden. SOLUTION: This extendable fence is obtained by forming a fence 1 surrounding the periphery of a cultivating bed E1 to E3 by joining plural pieces 16 and 17 having prescribed shapes and also recessed joint parts 18 at a prescribed distance at the side surface of the fence 1 by the joined pieces 16, 17. In this case, the pieces 16 and 17 having a thick thickness and a thin thickness are prepared, and the recessed joint parts 18 at a prescribed distance are formed by joining the thick thickness part and the thin thickness part alternately.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a step fence surrounding a plant cultivation floor such as a flower bed, and more particularly to a step fence which can be added to an arbitrary shape.

[0002]

2. Description of the Related Art In recent years, so-called gardening for making a garden in a miniature garden style at home has become popular. In this kind of gardening, the arrangement of vegetation is often changed in order to achieve a change of mind. Therefore, conventionally, plants are cultivated in a planter in which a synthetic resin material is formed in a box shape with a bottom, and the planter is moved as necessary to change the arrangement of the plants.

[0003]

However, even if a garden is constructed by arranging a large number of planters, the inorganic outer walls of the planters are conspicuous, causing a sense of incompatibility with plants and trees, and a relatively large gap is formed between adjacent planters. There was a problem that lacked a sense of unity.

Accordingly, the present invention solves such a problem, and provides an expandable step wall which can easily rearrange vegetation without impairing harmony with vegetation and a sense of unity as a garden. The purpose is to provide.

[0005]

In order to achieve the above object, according to the present invention, a plurality of pieces (2, 3) of a predetermined shape are connected to a step wall (1) surrounding the cultivation floor (E1 to E3). The joints (2, 3) are formed in such a manner that the recessed joint portions (18) are formed at predetermined intervals on the side surfaces of the step wall (1).

[0006] In the present invention, a plurality of pieces are appropriately connected to form a step, so that a step in a desired shape can be freely formed. In this case, if the pieces are made detachable, the shape of the stairs can be freely changed, and the arrangement of plants can be easily changed. And, the appearance of the terrace made up of a plurality of pieces is more in harmony with the plants than the relatively large inorganic outer wall of the conventional planter. In particular, if the pieces are made of wood, the scraps can be effectively used, and there is almost no sense of incompatibility with plants.
Also, since there is no gap as when a large number of planters are arranged, the sense of unity of the whole garden is not impaired.

[0007] Further, in the above-mentioned step wall formed by connecting pieces, joint portions depressed on the side surfaces thereof are formed at predetermined intervals, so that the joint portions produce a visual rhythm feeling and are excellent in design. It will be. In this case, if the gap is set so that the joint of the concrete block etc. always comes to the joint of the step, the design will be unified even when the step is constructed in combination with the concrete block etc. Can be.

The joint portions (18) at the predetermined intervals can be formed by alternately connecting thick pieces (2) and thin pieces (3). In addition, peace (5)
Is formed by projecting a thin leg portion (51) from a thick body and connecting another thick piece (3) to the tip of the leg portion (51). Joint portions (18) can be formed.

The above-mentioned pieces (2, 3) are connected by a convex portion (32) and a concave portion (21) formed on the side surfaces of each other in the height direction.
Can be done with When the convex portion (32) or the concave portion (21) is formed in a circular shape in a plan view, it is easy to manufacture, and the connection state is maintained by slightly widening the opening of the concave portion so that one piece is connected to the other piece. It is possible to change the joint angle of the two pieces by rotating the two pieces.

[0010] The reference numerals in parentheses indicate the correspondence with specific means described in the embodiment described later.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) FIG. 1 shows the appearance of a flower bed using a stairway of the present invention. The flowerbed is surrounded by the terrace 1 and three cultivation floors E1 by the terrace 1
To E3, and different flowers are planted on the respective cultivation floors E1 to E3. Among them, the cultivation floor E1 is formed in a fan shape having a curved portion and a straight portion in plan view, the cultivation floor E2 is formed in a square shape, and the cultivation floor E3 is formed in an L shape. Then, soil and hydroballs are put into the cultivation floors E1 and E2 at the same depth, and the cultivation floor E3 is occupied by other cultivation floors E1 and E2.
The soil and hydroball are deeper than 2. The fence 1 is formed by connecting a number of pieces 16 and 17, and the appearance of the fence 1 is shown in FIG.

In FIG. 2, the outer periphery of the cultivation floors E1, E2,
And a step fence 1 that partitions the boundaries of these cultivation floors E1 and E2
Is composed of a number of low-pieces 16, while
The outer perimeter of the cultivation floor E3, and the step wall 1 that defines the boundary between the cultivation floors E3 and E1 and E2 are formed by connecting a number of high pieces 17 and open upward to the cultivation floors E1 to E3. Spaces of a predetermined depth are formed, and soil is put in these spaces. In the step wall 1 formed by connecting the pieces 16 or 17, recessed joint portions 18 are formed at predetermined intervals on inner and outer side surfaces. Note that the pieces 16 and 17 described above are given reference numerals only to indicate that they have different heights, and pieces of various shapes described below are used to actually form the terrace 1.

FIGS. 3 and 4 show an example of the piece 2 constituting the step fence 1. FIG. 3 is a perspective view of the piece 2, and FIG. 4 is a plan view of the piece 2. The piece 2 is a thick wooden pillar having a height H, and its plane shape is a rectangle having a length L and a width W with four corners rounded. Notches 21 are formed on both sides in the longitudinal direction of the piece 2 and penetrate in the vertical direction. These notches 21 are opposed to a circular concave portion 211 having a radius R and a parallel opposing opening laterally with a width a and a length b. And an opening 212 having a surface.

FIGS. 5 and 6 show still another piece 3, FIG. 5 is a perspective view of the piece 3, and FIG. 6 is a plan view of the piece 3. The piece 3 is a thin-walled column having the same height H as the piece 2 described above, and has a plane shape having a constant width a and a length M, and circular projections 3 having a radius R formed at both ends thereof.
It consists of two. It is necessary to satisfy M> 2b, and an example of each dimension (unit: mm) is H = 100, L = 4
0, W = 30, R = 7, M = 20, a = 10, b = 5. Hereinafter, the same reference numerals are given to the same dimensions in each drawing.

To connect the pieces 2 and 3 to each other,
As shown in FIG. 7, the circular projection 32 of the piece 3 is
Of the circular concave portion 211 is inserted and fitted from above and below. Then, the pieces 2 and 3 are alternately fitted to each other by fitting the circular convex portions 32 and the circular concave portions 211 to each other, whereby the linearly extending step wall 1 is formed. Since the thin piece 3 exists between the thick pieces 2, the inner and outer side surfaces (up and down in FIG. 7) of the step wall 1 are depressed at this portion to form the joint portion 18. This joint 18
When the size of each of the pieces 2 and 3 is manufactured using the above-described example, the pieces are formed with a length of 10 mm every 40 mm.

The piece 4 shown in FIG. 8 has the same outer shape as the piece 2 already described, and the opposing surface of the opening 412 following the circular recess 411 of the notch 41 is outwardly inclined at an angle of θ outward. . Note that the opening interval a ′ of the opening 412 needs to be larger than the width a of the leg 31 of the piece 3.
When the above-mentioned piece 3 is connected to such a piece 4, FIG.
In the connected state, the pieces 3 can be swung right and left (up and down in the figure) within the angle of θ as shown by the dashed line. Fence 1 can be made. The opening 412
The piece 3 can be swung even if the circular concave portion 411 is directly opened to the side with an opening larger than the width a without forming the recess.

In the piece 5 shown in FIG. 9, legs 51 each having a width a and a length c protrude from both side surfaces of a column having the same basic shape as the piece 2 (FIG. 4). Is formed with a circular convex portion 52 having a radius R. Note that c> b
(FIG. 4). Such a piece 5 has its circular convex portion 5
2 are circular recesses 211, such as pieces 2 and 4 (FIGS. 4 and 8).
411 is used by inserting and connecting. At the time of this connection, the joint portions 18 (see FIG. 7) are formed by the thin leg portions 51. Each of the pieces described in the following drawings is the same column as the pieces 2 and 3 (FIGS. 3 and 5).

The piece 6 shown in FIG. 10 is used for a corner portion of the step fence 1 and has notches 61 formed at positions separated by 90 degrees, and circular notches 611 of these notches 61 are formed.
And circular convex portions 32 and 52 such as pieces 3 and 5 (FIGS. 6 and 9).
Are plugged and connected. The piece 7 shown in FIG.
The leg 71 protrudes from a position 90 degrees apart and a circular convex portion 72 is formed at the tip of the leg portion 71. These circular convex portions 72 are pieces 2 and 4 (FIGS. 3 and 8).
Etc., and are inserted and connected to the circular concave portions 211 and 411.

Pieces 8 to 10 shown in FIGS.
Are for three branches, respectively, and piece 8 (FIG. 12)
In FIG. 7, notches 81 are formed at positions opposite to each other by 180 degrees, and legs 82 and circular convex portions 83 are formed at positions 90 degrees away from these notches 81. In the piece 9 (FIG. 13), notches 91 are formed at positions separated by 90 degrees, and one of the notches 91 is 180 degrees.
A leg portion 92 and a circular convex portion 93 are formed at opposite positions separated by a distance. Further, in the piece 10 (FIG. 14), the leg 101 and the circular convex 102
Are formed.

FIGS. 15 to 19 show pieces 11 to 15 for four branches, respectively. In the piece 11 (FIG. 15), notches 111 are formed at opposite positions separated by 180 degrees, and legs 112 and circular convex portions 113 are formed at positions orthogonal to the notches 111, respectively. The piece 12 (FIG. 16) has the same basic shape as the piece 11, and has leg portions 121 which are 180 degrees apart and located at opposite positions.
Are formed shifted from each other in the left-right direction. Peace 13
In FIG. 17, the notch 131, the leg 132, and the circular protrusion 133 are respectively provided at positions separated by 90 degrees in the circumferential direction.
Are formed. In the piece 14 (FIG. 18), legs 141 and circular convex portions 142 are formed at positions separated by 90 degrees in the circumferential direction, respectively. Piece 15 (Fig. 19)
Has the same basic shape as that of the piece 14, and has leg portions 151 at opposite positions 180 degrees apart from each other and formed to be shifted from each other in the left-right direction.

By appropriately selecting and connecting the various pieces described above, not only the step 1 shown in FIG. 2 but also steps of various shapes can be freely formed. Then, even after the formation of the fence, once the appropriate number of pieces are removed or added, the shape of the fence can be changed, and the flowerbed can be easily redesigned. Note that each of the above-described pieces is merely an example, and the outer shape is not limited as long as it has a circular concave portion and a circular convex portion that fit together.

The concave portion and the convex portion for connecting the pieces to each other are not limited to a circle but may be a square or the like. However, the circular shape is easier to manufacture, and as shown in FIG. On the other hand, a structure in which the other piece 3 is swung at a predetermined angle can be easily realized. Further, the concave portion and the convex portion do not necessarily need to penetrate the column vertically, and may have a structure in which only one end of the concave or convex portion reaches the upper end or the lower end of the column.

If the piece is made of wood as described above, it is possible to effectively use the offcuts and it is easy to harmonize the texture with the vegetation. However, the piece is not necessarily made of wood and may be made of synthetic resin, rubber or It may be made of ceramics or glass. In addition, by preparing a plurality of types of pieces having the same shape and different colors, it is possible to form a gorgeous step wall. The use of the extendable fence of the present invention is not limited to flower beds, but can also be used in home gardens and the like.
In addition, since such terraces are planted with vegetation in the ground, it is possible to plant trees, vegetables, and the like that are deeply rooted in the ground. In addition, a bottom plate may be attached to the terrace. Further, the pieces can be connected to each other and used as a partition for the interior. In the above embodiment, the pieces can be separated. However, the pieces may be fixed so that they cannot be separated at the manufacturing and selling stage.

(Second Embodiment) As shown in FIG. 20, a piece 2 (FIG. 3) and a piece 3 (FIG. 5) connected to each other
Then, the height of the piece 3 is made higher than the height of the piece 2 to protrude downward, and if this protruding portion is buried in the soil, the positioning of the step wall 1 can be surely performed. Note that the height of the piece 2 may be higher than the height of the piece 3, and the protruding portion may be buried in the soil.

(Third Embodiment) As shown in FIG. 21, the pieces 2 (FIG. 3) and the pieces 3 (FIG. 5) are connected to form step walls 1 and 1 'extending in parallel. , 1 ', a new cultivation bed can be formed between the steps 1 and 1'.

(Fourth Embodiment) Using the piece 3 (FIG. 5) and the piece 4 (FIG. 8), as shown in FIGS. When the fence 1 and the step fence 1 'that curves downward in the figure are configured, the main body length M1 of the piece 3 forming the fence 1 is changed to the main body length M2 of the piece 3 forming the fence 1'. If the length is longer than the appropriate amount, the length L of the joint portion 18 of the step walls 1 and 1 ′ as viewed from below can be made the same.

(Fifth Embodiment) The height of the piece 3 (FIG. 5) is reduced to half the height of the piece 2 (FIG. 3), and the upper and lower pieces are connected between the pieces 2 as shown in FIG. If the upper piece 3 is appropriately lifted to form a gap 33 between the upper piece 3 and the lower piece 3, the gap 33 can be used as a drain hole or a hole for passing a water supply pipe.

(Sixth Embodiment) As shown in FIG. 24, the height of the piece 2 (FIG. 3) is set to half the height of the piece 3 (FIG. 5) at an appropriate position, and the height of the piece 3 Of the half (that is, the same height as the piece 2) (FIG. 12), and the legs 82 are projected at a plurality of places into the cultivation floor surrounded by the step wall 1 as shown in FIG. . If a floor plate of a cultivation floor is prepared and its periphery is placed on and supported by the legs 82, soil can be put on the floor plate and used on a veranda or the like.

[0029]

As described above, the extendable steps of the present invention can be easily rearranged without compromising the harmony with the plants and the sense of unity as a garden.

[Brief description of the drawings]

FIG. 1 is an overall perspective view of a flower bed using stairs in a first embodiment of the present invention.

FIG. 2 is an overall perspective view of a step wall.

FIG. 3 is an overall perspective view of a piece.

FIG. 4 is a plan view of a piece.

FIG. 5 is an overall perspective view of a piece.

FIG. 6 is a plan view of a piece.

FIG. 7 is a partial plan view of a step wall.

FIG. 8 is a plan view of a piece.

FIG. 9 is a plan view of a piece.

FIG. 10 is a plan view of a piece.

FIG. 11 is a plan view of a piece.

FIG. 12 is a plan view of a piece.

FIG. 13 is a plan view of a piece.

FIG. 14 is a plan view of a piece.

FIG. 15 is a plan view of a piece.

FIG. 16 is a plan view of a piece.

FIG. 17 is a plan view of a piece.

FIG. 18 is a plan view of a piece.

FIG. 19 is a plan view of a piece.

FIG. 20 is a perspective view of pieces connected to form a step wall in the second embodiment of the present invention.

FIG. 21 is a plan view of pieces connected to form a step wall in the third embodiment of the present invention.

FIG. 22 is a plan view of pieces connected to form a step wall in the fourth embodiment of the present invention.

FIG. 23 is a perspective view of pieces connected to form a step wall in the fifth embodiment of the present invention.

FIG. 24 is a perspective view of pieces connected to form a step wall in the sixth embodiment of the present invention.

FIG. 25 is a plan view of a step wall.

[Explanation of symbols]

1 ... terrace, 2,3,4,5,6,7,8,9,10,1
1,12,13,14,15,16,17 ... piece, 1
8. Joint part, 21, 41, 61, 81, 91, 11
1, 131 ... notch, 211, 411, 611 ... circular concave part, 32, 52, 72, 83, 93, 102, 113,
133, 142 ... circular convex portions, 51, 71, 82, 92,
101, 112, 121, 132 ... legs, E1, E2,
E3: Cultivation floor.

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[Procedure amendment]

[Submission date] April 27, 1999

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claims

[Correction method] Change

[Correction contents]

[Claims]

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0004

[Correction method] Change

[Correction contents]

[0004] The present invention is intended to solve such problems, without impairing the sense of unity harmony and gardens and plants, and on it is possible to easily rearrange the plants
And secure the positioning of the stairs, or facilitate drainage holes
It is an object of the present invention to provide a stepped wall that can be formed .

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] 0005

[Correction method] Change

[Correction contents]

[0005]

In order to achieve the above object, according to the first aspect of the present invention, a step wall (1) surrounding the cultivation floor (E1 to E3) is provided with a plurality of columnar pieces (2, 3). together constituting bind to the, by combined pieces (2, 3), recessed joint portion (18) without so formed at predetermined intervals on the side surface of Dankaki (1), the piece thick of
The thing (2) and the thin thing (3) are prepared.
(2) and thin pieces (3) are alternately joined
Of the thin piece (3) located between the sides of the piece (2)
The recessed joint portion (18) is formed by the side surface.
Sea urchin, connect the pieces (2, 3) to each other
A circular recess (21) extending in the height direction to the upper end and the lower end
This is done with a circular projection (32) that is inserted and fitted into this
And thin pieces (3) or thick pieces
Make one of the lengths of (2) longer than the other
The other piece (3) is lower than the other piece (2)
So that it protrudes toward

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0006

[Correction method] Change

[Correction contents]

In the first aspect of the present invention, a plurality of pieces are appropriately connected to form a step wall, so that a step wall of a desired shape can be freely formed. In this case, if the pieces are made detachable, the shape of the stairs can be freely changed, and the arrangement of plants can be easily changed. And, the appearance of the terrace made up of a plurality of pieces is more in harmony with the plants than the relatively large inorganic outer wall of the conventional planter. In particular, if the pieces are made of wood, the scraps can be effectively used, and there is almost no sense of incompatibility with plants.
Also, since there is no gap as when a large number of planters are arranged, the sense of unity of the whole garden is not impaired.

[Procedure amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0007

[Correction method] Change

[Correction contents]

[0007] In addition, the above-mentioned step fence is provided between the sides of a thick piece.
Are formed at predetermined intervals by the side surfaces of the thin piece located at the predetermined distance, so that the joint produces a visual rhythm feeling and is excellent in design. In this case, if the gap is set so that the joint of the concrete block etc. always comes to the joint of the step, the design will be unified even when the step is constructed in combination with the concrete block etc. Can be. Further down
Fill the protruding piece in the soil to position the fence securely
can do.

[Procedure amendment 6]

[Document name to be amended] Statement

[Correction target item name] 0008

[Correction method] Change

[Correction contents]

[0008] In the second invention, the cultivation floor (E1 to E3)
The step wall (1) surrounding the periphery is divided into a plurality of pillar-shaped pieces (2,
3) Combined and configured, and combined pieces
Due to (2, 3), the recessed joint part (18) is a terrace
(1) to be formed at a predetermined interval on the side surface;
Pieces are available in thick (2) and thin (3) pieces
Alternate between thick pieces (2) and thin pieces (3)
The thin-walled piece located between the sides of the thick piece (2)
The joint (1) recessed by the side surface of the piece (3)
8) to form the connection of the pieces (2, 3).
Circles that extend in the height direction on each side and reach the upper and lower ends
-Shaped concave part (21) and circular convex part inserted and fitted therein
(32) and the thin piece (3)
With the length being 1/2 of the length of the thick piece (2)
Then, the thin-walled pin located on the upper side between the thick pieces (2)
One of the bases (3) is slidable upward.

[Procedure amendment 7]

[Document name to be amended] Statement

[Correction target item name] 0009

[Correction method] Change

[Correction contents]

In the second invention, a plurality of pieces are applied.
Since the fences are constructed by connecting them together,
You can make it freely. In this case, separate the pieces
If possible, you can freely change the shape of the fence
Can be easily rearranged. Soshi
The appearance of the terrace made up of multiple pieces is
Better than the relatively large inorganic outer wall of the plant
Harmonize. In particular, if the pieces are made of wood,
It can be used effectively and there is almost no discomfort with plants.
Also, do not create gaps like when many planters are arranged.
Therefore, the sense of unity of the whole garden is not lost. In addition,
On the fence, the thin-walled piece located between the sides of the thick piece
The joints that are depressed by the sides of the
This joint creates a sense of visual rhythm,
It will be excellent in property. In this case, the concrete block
So that the joint part of the terrace wall always comes to the joint part of
If the interval is set, it can be combined with concrete blocks, etc.
Even if a terrace is constructed together, it is important to unify the design.
Can be. Then slide one of the thin pieces upward
And pull it up, a thin piece located on the lower side
A gap is formed between the other
It can be used as a hole or a hole through a water supply pipe.
it can.

[Procedure amendment 8]

[Document name to be amended] Drawing

[Correction target item name] FIG.

[Correction method] Change

[Correction contents]

FIG.

[Procedure amendment 9]

[Document name to be amended] Drawing

[Correction target item name] FIG.

[Correction method] Change

[Correction contents]

FIG. 23 ────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] August 9, 1999

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claims

[Correction method] Change

[Correction contents]

[Claims]

1. A step wall surrounding the cultivation floor is formed by connecting a plurality of column-shaped pieces, and the joined pieces form concave joints at predetermined intervals on side surfaces of the step wall. The pieces are prepared in the form of a thick piece and a thin piece, and the thick piece and the thin piece are alternately connected to each other to form the thin piece positioned between the side faces of the thick piece. The concave joint portion is formed by the side surface, and the pieces are connected by a circular concave portion extending in the height direction to each side surface and reaching the upper end and the lower end, and a circular convex portion inserted and fitted into the concave portion. to, and the height of the thin piece of half the height of the thick piece thin
Characterized in that one piece of each piece is provided above and below, and a thin piece positioned above the thick piece is slidable upward.

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0004

[Correction method] Change

[Correction contents]

Accordingly, the present invention is to solve such a problem, and it is possible to easily rearrange the vegetation without impairing the harmony with the vegetation and the sense of unity as a garden, and to provide a drainage hole . It is an object of the present invention to provide a stepped wall that can be easily formed.

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] 0005

[Correction method] Deleted

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0006

[Correction method] Deleted

[Procedure amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0007

[Correction method] Deleted

[Procedure amendment 6]

[Document name to be amended] Statement

[Correction target item name] 0008

[Correction method] Change

[Correction contents]

[0008]

According to the present invention , a cultivation bed (E
Steps (1) surrounding the periphery of 1 to E3) are formed by connecting a plurality of columnar pieces (2, 3), and the joined pieces (2, 3) form a concave joint portion (18). )
Are formed at predetermined intervals on the side surface of the step wall (1), and the pieces are thick (2) and thin (3)
Is prepared, thick piece (2) and thin piece (3)
Are alternately connected to form the concave joint portion (18) by the side surface of the thin piece (3) located between the side surfaces of the thick piece (2).
The connection of 3) is performed by a circular concave portion (21) extending in the height direction to the side surfaces of each other and reaching the upper end and the lower end, and a circular convex portion (32) inserted and fitted in the circular concave portion (21). the height of 3) of half the height of the thick piece (2)
One thin piece (3) is provided above and below each thin piece (3) so that the thin piece (3) positioned above between the thick pieces (2) can be slid upward.

[Procedure amendment 7]

[Document name to be amended] Drawing

[Correction target item name] FIG.

[Correction method] Change

[Correction contents]

FIG. 23

Claims (5)

[Claims] 1. A step wall surrounding the periphery of a cultivation floor is formed by connecting a plurality of pieces of a predetermined shape, and a concave joint portion is formed at a predetermined interval on a side surface of the step wall by the connected pieces. An expandable terrace that is characterized by being done. 2. The expansion unit according to claim 1, wherein thick and thin pieces are prepared for the pieces, and the thick and thin pieces are alternately joined to form the joint portion at the predetermined interval. Possible terraces. 3. The piece is formed by projecting a thin-walled leg from a thick-walled main body, and another thick-walled piece is joined to the tip of the leg to form the joint portion at the predetermined interval. The expandable step wall according to claim 1. 4. The combination of said pieces is performed by a convex portion and a concave portion formed on a side surface of each other in a height direction.
Steps that can be added as described in any one of 3 to 3. 5. The extendable step wall according to claim 4, wherein the convex portion or the concave portion has a circular shape in plan view.