JP6562578B1 - Bonded wood composite for double floor and double floor structure using the composite - Google Patents

Abstract

An object of the present invention is to provide a wood composite material for a double floor which is sufficiently strong in the construction of only a joined wood composite material by actual joining without a floor base material. A double-floor wood composite material 1 is a rectangular member composed of a wood core material 1a and wood fiber boards 1b and 1c laminated on both upper and lower surfaces of the core material 1a. A male fruit 2 is provided on two adjacent sides of the wood core 1a, and a female fruit 6 is formed on the remaining two sides. The length L2 to the tip 6f of the lower piece 6b of the female fruit 6 is formed larger than the length L1 to the tip 6e of the upper piece 6a. Thereby, the bonding length of the lower piece 6b side becomes larger than that of the upper piece 6a side, and the bonding force of this portion is increased compared to the actual coupling of the upper and lower pieces 103a and 103b having the same length. For this reason, when the wood composite A joined downward is loaded with a load F from above on the double floor, even if tensile stress due to the bending is applied to the actual joint portion H, this portion H There will be no breakage. [Selection] Figure 2

Description

The present invention relates to a bonded wood composite material capable of forming a double floor without a floor foundation and a double floor structure using the composite material.

  Recently, it has become popular to provide fashionable temporary or permanent talk spaces and cafe spaces that incorporate an open atmosphere of Western style that easily encloses the free space of many multi-storey buildings such as apartment buildings and office buildings. Yes. On the floor of such a space, wiring cords or equipment pipes that impair the appearance are hidden under the floor so that they do not appear outside, or when footsteps occur when many people enter or leave the space Therefore, a double floor structure is used (Patent Document 1).

JP-A-2005-232796

  In such a double floor, as shown in FIG. 6, the floor base material 105 such as a particle board is used, and the support tool 120 erected on the floor surface 110 such as a concrete slab is used. Supports the four corners. Since the long side (for example, 1,800 mm) of the floor base material 105 has a length three times that of the short side (for example, 600 mm), when the support 120 is installed at each corner, Three times as many support tools 120 as the long side are installed. A floor finishing material 100 is further laid on the floor base material 105 to form a double floor structure. The actual processing (or peeling processing and agitation processing can also be applied) is performed on the four circumferences of the floor finishing material 100 and connected by actual joining.

  A base material such as a particle board used for the floor base material 105 is required to have a gap 107 of about 10 to 15 mm between the floor base materials 105 due to its characteristics. Since this gap 107 exists, a thin finishing material such as a cushion floor cannot be used as the floor finishing material 100. As a result, the conventional double floor has a double structure of a floor finish material 100 and a thick floor finish 100 that is not affected by the gap 107, so that the thickness of the entire double floor is increased, As described above, there is a disadvantage in terms of construction period and cost, such as requiring floor foundation construction and floor finishing construction.

Therefore, as shown in FIG. 7, the floor base material 105 is not used, and a floor finishing material 100 such as a general wood flooring is actually used, and the floor base material 105 has substantially the same size as the long side and the short side. It is also conceivable to form a double floor without the floor base material 105 by using one bonded floor finish B. Although the length of the short side of the floor finishing material 100 is the same as the length of the short side of the floor base material 105, the length of the long side of the floor finishing material 100 is the length of the long side of the floor base material 105. Therefore, when the installation interval of the support member 120 is the interval when the floor base material 105 is used as described above, the actual joint position H is between the support members 120. Of course, the support 120 is not provided in the portion H. The actual processed female seed 103 is simply a groove formed in the entire end face of the floor finishing material, and the upper piece 103a and the lower piece 103b constituting the female fruit 103 have the same dimensions, so that the actual processing is performed. Even if the insertion protrusion 101a of the male fruit 101 is inserted into the female fruit 103 and this part H is bonded, there is a problem in strength as follows.

  In other words, in a double floor structure consisting only of bonded floor finish B by actual joint without floor base material, it is applied to load F (static load when furniture is installed, point load due to human movement) applied after double floor construction. There is a risk that the joint floor finishing material B (particularly, the joint portion H) may be damaged, such as being unbearable. If the support tool 120 is added below the actual joint portion H, a double floor structure having only the floor finishing material 100 by the actual joint without the floor base material 105 can withstand the load. This will greatly increase the number of devices and cannot be adopted in terms of cost and construction.

The present invention was made in order to solve the above-described problems of the conventional example, and is a construction using only a joined wood composite material (corresponding to a joined floor finish material) by actual joining without a floor base material and the joined wood composite material. The issue is to provide a double-floor structure with sufficient strength .

The invention described in claim 1
A wood core 1a, consists of a wood fiber board 1b · 1c laminated on upper and lower surfaces in the core material 1a, Omi 2 is provided on two adjacent sides of the wooden core member 1a, the two sides remain For a double floor, a female fruit 6 is formed, and the length L2 to the tip 6f of the lower piece 6b of the female fruit 6 is greater than the length L1 to the tip 6e of the upper piece 6a of the female fruit 6 . In the joined wood composite material A, in which the short sides of the two wood composite materials 1 are joined together, and only the four corners are the attachment portions of the support tool 20,
A reinforcing plate 9 having a width covering the short side of the adjacent wood composite material 1 and covering the actual joint portion H is bonded to the lower surface of the actual joint portion H.

In this wood composite material 1, since the lower piece 6b is made longer than the upper piece 6a, when the adjacent wood composite material 1 is actually connected, the lower piece 6b side has a larger bonding length than the upper piece 6a side. The joining force of this portion is increased compared to the actual coupling in which the upper and lower pieces 103a and 103b have the same length. Therefore, a wooden composite material A (hereinafter referred to as a joined wooden composite material A, which is loaded downward with a load F applied to the double floor, and when it is necessary to distinguish in a subordinate concept, When a bending stress is applied to the actual joint portion H, the fracture at the portion H does not occur.
The male fruit 2 and the female fruit 6 are provided in the wood core 1a and do not reach the wood fiber boards 1b and 1c having rigidity and toughness. The guarantee of the strength of the female seed 6 can be given by the wood fiber board 1c constituting the portion.

Claim 2 relates to the joint relationship between the male fruit 2 and the female fruit 6 of the woody composite material 1 according to claim 1.
On the lower surface side of the wood composite material 1 on the side where the male fruit 2 is formed, the lower surface side wood fiber board 1c and a part of the wood core material 1a are cut into a step shape, and the lower piece 6b of the female fruit 6 is attached. A lower stepped cut portion 2b is formed,
On the upper surface side of the wood composite material 1, a part of the upper surface side wood fiber board 1b and the wood core material 1a are cut in a step shape to form an upper surface stepped cut portion 2a to which the upper piece 6a of the female fruit 6 is attached. ,
Between the upper surface stepped cutout portion 2a and the lower stepped cutout portion 2b, an insertion convex portion 2c that is fitted into the groove 6c of the female seed 6 is formed,
The length L1 of the upper piece 6a is longer than the length S1 from the cut end 2s of the upper stepped cut portion 2a of the male 2 to the tip 2e of the insertion convex portion 2c, and
The length L2 of the lower piece 6b, which is the length from the groove bottom 6d of the groove 6c of the female fruit 6 to its tip 6f, is the length from the tip 2e of the insertion protrusion 2c to the cut end 2f. From the length S2 of the lower stepped cut portion 2b and the length L1 of the upper piece 6a that is the length from the groove bottom 6d to the tip 6e of the groove 6c, the tip 2e of the insertion convex portion 2c. It is characterized by being formed shorter than the sum of the difference D obtained by subtracting the length S1 of the insertion convex portion 2c which is the length from the cutting end 2s .

Claim 3 is the bonded wood composite material A according to claim 1 or 2 ,
On the lower surface on the short side where the female fruit 6 is provided, a position separated from the front end 6f of the lower piece 6b by 3/8 to 5/8 of the mounting width T of the floor support 26 of the support 20 is defined as a starting point 8a. A positioning member 8 is provided at the above position.

Since the actual shape is configured as described above, the tip 6e of the upper piece 6a comes into contact with the cut end 2s of the upper surface stepped cut portion 2a when it is actually joined. At this time, the tip 2e of the insertion protrusion 2c contacts or separates from the groove bottom 6d of the female fruit 6, and the tip 6f of the lower piece 6b contacts or separates from the cut end 2f of the lower stepped cutout 2b.
Therefore, when the load F is applied from above and the joined wood composite material A tries to bend downward as described above, the stiffness of the wood composite material 1 constituting the joined wood composite material A is high and compressed on the upper surface side. On the other hand, the wood fiber boards 1b having high resistance are not brought into contact with each other at the joint portion and deformed, and the lower piece 6b made of the wood fiber board 1b having high rigidity and toughness is pulled on the lower surface side of the wood composite material 1. In addition to being highly resistant to the deformation, the downward deflection is not restricted, and breakage of this portion H is avoided.

Further, if the reinforcing plate 9 is attached across the short side of the adjacent wood composite material 1 on the lower surface of the actual joint portion H, the lower piece 6b is further reinforced, and damage to the portion H can be avoided. .
Moreover, if the positioning member 8 is provided in the said part, if the said positioning member 8 is butt | laid and laid, it will butt | lay on the edge part of the floor support part 26 of the support tool 20 to which the short side of this male 2 side is attached, Since the actual joint portion H is located at the approximate center of the floor support portion 26 of the support tool 20, accurate double floor construction can be performed more easily.

Claim 4 is a double floor structure using the joined wood composite material A for double floor according to any one of claims 1 to 3 ,
A plurality of support tools 20 erected on the floor surface 11 according to the four corners of the bonded wood composite material A according to any one of claims 1 to 3 ,
It is constructed of a joined wood composite material A laid on the support 20 and adjacent sides are joined together.

  Since the wood composite material for double floors of the present invention has the actual shape as described above, the double floor is sufficient in strength by the construction of only the joined wood composite material by the actual joint without using the floor base material. Can be built.

It is a top view of the double floor structure of this invention. It is sectional drawing of FIG. It is an expanded sectional view of the actual joint part screwed to the support tool of FIG. It is an expanded sectional view of the actual joint part to which the reinforcement board of FIG. 2 was attached. It is a top view of the other double floor structure of this invention. It is sectional drawing of the prior art example 1. FIG. It is a fragmentary sectional view of the actual joint part of the prior art example 2.

  Hereinafter, the present invention will be described in detail according to illustrated embodiments. The wood composite material 1 for double floors is a rectangle (wood plate 1b and a wood fiberboard 1b and 1c laminated integrally by adhesion on the upper and lower surfaces of the wood core 1a). In the example, it is a rectangle, but it may be a square.) In this embodiment, the wood composite 1 is rectangular and the ratio of short side to long side is 1 to 1.5. The length of the short side of the wood composite material 1 is the same as the short side of the floor base material 105, and the length W on the long side is the long side of the floor base material 105 that has been conventionally used. Less than the length Y. That is, the long side length W of the wood composite material 1 is ½ of the long side length Y of the floor base material 105.

  Taking the actual dimensions as an example, the floor base material 105 conventionally used has a short side length of 600 mm and a long side length of 1,800 mm. The length of this is 600 mm and the length of the long side is 1900 mm.

As the wood core material 1a, a plywood having high strength and no directivity, an oriented strand board / OSB, or a single board laminated material / LVL (Laminated Veneer Lumber) is used. A plate | board thickness is 9-24 mm, for example, More preferably, it is 12-15 mm.
As the wood fiber boards 1b and 1c, a material having rigidity and toughness, for example, a medium density fiber board, which is a kind of molded board made of wood fibers, is used. The plate thickness is, for example, 2.5 to 4.0 mm, and more preferably 2.5 to 4.0 mm.

The wood core 1a of the wood composite material 1 is provided with a male fruit 2 over its entire length on two adjacent sides and a female fruit 6 over its entire length on the remaining two sides. In other words, the groove 6c of the female fruit 6 is formed only in the wood core 1a and does not reach the wood fiber boards 1b and 1c.
The length L2 of the lower piece 6b of the female fruit 6 is the length from the groove bottom 6d of the groove 6c to the tip 6f thereof, and the length L1 of the upper piece 6a is from the groove bottom 6d of the groove 6c to the tip 6e thereof. It is the length until. The length L2 of the lower piece 6b is formed larger than the length L1 of the upper piece 6a. In this embodiment, the length L2 is about 1.5 to 2.5 times the length L1. A recess 6k for screw driving is formed on the upper surface of the lower piece 6b at a portion protruding from the upper piece 6a of the lower piece 6b. The width of the real part of the present invention is indicated by Z. The recesses 6k may be provided at regular intervals over the entire length of the upper surface of the lower piece 6b, or may be provided on the upper surface of the lower piece 6b at the corner portion of the wood composite material 1 so as to match a floor support portion 26 of the support 20 described later. It may be provided.

  The male fruit 2 has a lower surface stepped cut portion 2b in which a part of the lower surface side wood fiber board 1c and the wooden core material 1a are cut in a step shape on the lower surface side of the wood composite material 1 on the side where the male fruit 2 is formed. Is formed. Similarly, on the upper surface side of the wood composite material 1, a part of the upper surface side wood fiber board 1b and the wood core material 1a are cut in a step shape to form an upper surface stepped cut portion 2a. Between the upper surface stepped cut portion 2a and the lower surface stepped cut portion 2b, an insertion convex portion 2c, which is fitted into the groove 6c of the female fruit 6, is formed by an uncut portion of the wood core 1a.

  The length S1 of the upper stepped cut portion 2a is the length from the tip 2e of the insertion convex portion 2c to the cut end 2s. Similarly, the length S2 of the lower surface stepped cut portion 2b is the length from the tip 2e of the insertion convex portion 2c to the cut end 2f. The length S2 of the lower surface stepped cut portion 2b is formed to be longer than the length S1 of the upper stepped cut portion 2a, and is formed in such a size that the lower piece 6b of the female fruit 6 is fitted and bonded.

  The connection relationship between the male fruit 2 and the female fruit 6 is greatly related to the strength of the joint part H, and the length L1 of the upper piece 6a is different from the cut end 2s of the upper stepped cut part 2a of the male fruit 2. The length L2 of the lower piece 6b, which is longer than the length S1 up to the tip 2e of the insertion convex part 2c, is different from the length S2 of the lower stepped cut part 2b and the length L1 of the upper piece 6a. It is shorter than the sum of the difference D obtained by subtracting the length S1 of the protrusion 2c. The connection state between the male fruit 2 and the female fruit 6 will be described later.

  The support 20 is a building member having a well-known structure, and is provided on a plate-like installation part 22 that is bonded and fixed to the floor 11 of the building, a column 24 that is erected on the installation unit 22, and an upper end of the column 24. It is composed of a floor support portion 26 that is round or rectangular (here, square). The support column 24 is cylindrical and has a sheath portion 24a in which an internal thread is engraved on the inner surface, and is screwed into the internal thread of the sheath portion 24a so as to be able to advance and retract, and is installed to be rotatable with respect to the installation portion 22. It is comprised with the support | pillar screw 24b which is. The sheath portion 24 a is suspended from the lower surface of the floor support portion 26. A driver hole (not shown) is formed in the floor support portion 26, and the column screw 24b is rotated through the driver hole so that the height of the floor support portion 26 can be adjusted.

Next, a procedure for constructing a double floor will be described. The dimensions of the wood composite material 1 are not limited to the above, but the dimensions as described above are used here for easy understanding.
The wood composite material 1 used in the present invention is rectangular and its long side length W is ½ of the long side of the floor base material 105 used in the conventional example. The short side of the wood composite material 1 of the present invention has the same length as the short side of the floor base material 105.
Then, two wood composite materials 1 are used, and the short sides thereof are joined together using an adhesive so as to have the same size as the conventional floor base material 105. The two joined woody composite materials 1 are referred to as a joined woody composite material A. As described above, when it is necessary to distinguish the joined wood composite material A, an Arabic numeral or a lower case alphabet is added to A.

  On the lower surface of the bonded wood composite material A, the reinforcing plate 9 is pasted over the entire length of the short side joint portion H. The joint line 7 of the actual joint portion H appearing on the lower surface of the joined wood composite material A is aligned with the center of the reinforcing plate 9 and bonded so that the left and right adhesive widths of the reinforcing plate 9 are equal with the joining line 7 as the center. In addition, it is preferable for the strength improvement that the width | variety of the reinforcement board 9 shall be the magnitude | size which can cover the actual joint part H. FIG. In addition, the material of the reinforcement board 9 has a preferable wood fiber board.

  Subsequently, on the lower surface of the bonded wood composite material A, the positioning member is spaced apart from the short side (tip 6f of the lower piece 6b) of the bonded wood composite material A on the female fruit 6 side by a predetermined dimension and parallel to the short side. 8 is bonded. The positioning member 8 is provided at a position separated by 3/8 to 5/8 (preferably 1/2 of the mounting width T) of the mounting width T of the floor support portion 26 of the support 20. In other words, similarly to the above, the joint line 7 of the actual joint portion H that appears on the lower surface of the joined wood composite A is aligned with the center of the floor support portion 26, and the left and right mounting widths of the floor support portion 26 with the joint line 7 as the center. Are preferably equal. The width T of the floor support 26 is preferably large enough to cover the actual joint H in terms of strength improvement. Further, the bonding of the positioning member 8 is provided over a corner portion of the joined wood composite material A, which is an attachment portion of the support 20 on the lower surface of the joined wood composite material A, or the entire short side of the male 2 side. The example in the figure is the latter.

  Next, the support 20 is installed on the floor surface 11 in accordance with the size of the bonded wood composite material A, which is substantially the same size as the conventional floor base material 105. In this case, the dimension Y in the long side direction of the bonded wood composite A is (1/3) · Y in the short side direction. The installation part 22 is bonded and fixed to the floor surface 11. Subsequently, the column screw 24 b is turned to adjust the height of the floor support portion 26, and finally, the joined wood composite material A is sequentially laid on the floor support portion 26.

When laying the bonded wood composite material A on the floor support portion 26, the four corners of the first bonded wood composite material A1 are installed on the corresponding floor support portions 26 respectively. At this time, the positioning member 8 is placed in contact with the side surface of the floor support portion 26 so that the short side of the positioning member 8 occupies 1/2 of the floor support portion 26. In other words, the tip 6f of the lower piece 6b of the female fruit 6 is positioned as centrally as possible in the floor support portion 26. After thus accurately positioned, the mark recesses 6k around the corner portions of the first sheet of the lower piece 6b of Mesumi 6 bonding wood composite A1, bis 28 the lower piece 6b to the floor support 26 And fix.

In this state, the long side of the second bonded wood composite material A2 is disposed along the long side of the first bonded wood composite material A1 screwed, and the long side is positioned as described above. Perform joints at the edges. Then, the lower piece 6b of the female fruit 6 of the second bonded wood composite material A2 is screwed as described above. In this way, the long sides are joined one after another, and when the joining of the first row is completed, the process moves to the second row.

The male fruit 2 of the joined woody composite material Am in the second row is inserted into the already fixed female fruit 6 of the joined woody composite material A1, and the lower piece 6b of the female fruit 6 on the opposite side is joined. Is fixed to the floor support portion 26 of the support 20 in the same manner as described above. In the second joined wood composite material An in the second row, the joined wood composite materials A1 and Am corresponding to the male 2 of the long and short sides are already laid and fixed with screws, so this joined wood composite material An actual splicing already insert the Omi 2 of the bonding wood composite an from Mesumi 6 direction of the bonding wood composite A1 · Am being laid, after combined actual bonding, the lower piece 6b of the Mesumi 6 Is screwed according to the above. Repeat this to build a double floor. The actual joint portion is bonded by an adhesive.

  Finally, in the empty space around the double floor formed by actual joining of the joined wood composite material A, the dancing member 1x obtained by cutting the wood composite material 1 with a necessary width is stretched, and the double floor and the floor surface 11 are connected. A plate material 1y that conceals the lower floor portion in between is attached, and a floor material 10 such as a tile carpet or flooring is laid on the joined wood composite material A as necessary to complete the construction of the double floor.

When the construction of the double floor is completed in this way, a table, a chair, and other furniture are installed thereon, and further, piping and wiring are installed under the double floor. When the installation is complete, it opens and accepts people. When a person visits, he / she walks on the double floor, and the double floor is subjected to a static load of furniture and a dynamic load due to movement of the person, and a force in a direction to bend the bonded wood composite A downward. Is constantly added. At this time, the maximum bending occurs in the joint portion H located at the central portion of the joined wood composite A, but (a) the lower piece 6b of the female seed 6 in the joint portion H is longer than the upper piece 6a, The joining force at the actual joint portion H is sufficiently larger than that of the conventional actual joint, (b) the reinforcing plate 9 is attached to the lower surface of the actual joint portion H, and (c) the male 2 is inserted. Since the convex portion 2c and the groove 6c of the female fruit 6 are limited to the wood core 1a formed of plywood or the like and do not reach the wood fiber boards 1b and 1c having rigidity and toughness, as described above, Even if the support member 20 is installed with the same span as the floor base material 105, the joined woody composite material A constituting the double floor will not break.

FIG. 5 shows a joined wood composite material A in which four wood composite materials 1 are joined by a longitudinal joint and a transverse joint. A reinforcing plate 9 is provided on the bottom surface of the actual joint portion over the entire length and width. The positioning member 8 is also attached to two wood composite materials 1 having long sides joined adjacent to the same position. In this case, the sum of the short sides of the two wood composites 1 with the long sides joined is longer than the length of the long side W of one wood composite 1, but When the double floor is formed by using the joined wood composite material A in which the four wood composite materials 1 are joined by the longitudinal joint and the transverse joint, since the length is shorter than the length Y, the two wood joints having the long sides joined together. The support 20 in the middle part of the short side of the composite material 1 can be omitted. The other points are the same as in the embodiment of FIG.
However, it has been found that the required performance when installing this double-floor structure, the conditions under the floor such as piping and wiring, and the indoor space (installation space for heavy objects such as washing machines) Depending on the installation conditions, the construction of the support tool 20 is not prevented from being increased.

A (A1 to An): joined wood composite material, F: load, H: actual joint portion, D: difference, L1: length of upper piece, L2: length of lower piece, S1: upper surface stepped portion Length, S2: Length of bottom stepped part, T: Width of floor support, W: Length of wood composite, Y: Length of joined wood composite, Z: Actual length according to the present invention 1: wood composite material, 1a: wood core material, 1b: top side wood fiber board, 1c: bottom side wood fiber board, 1x: dance member, 1y: board material, 2: male, 2a: top stepped cut Part, 2b: bottom stepped cut part, 2c: insertion convex part, 2e: tip of insertion convex part, 2s: cut end of top stepped part, 2f: cut end of bottom stepped part, 6: Female seed, 6a: upper piece, 6b: lower piece, 6c: groove, 6d: groove bottom, 6k: depression, 7: joining line, 8: positioning member, 8a: starting point, 9: reinforcing plate, 10: flooring, 11: Floor surface, 2 : Support, 22: installation part, 24: support, 24a: sheath, 24b: support screw, 26: floor support, 28: screw, 100: conventional floor finish, 101: real male, 101a : Real insertion convex part, 103: real female fruit, 103a: upper piece , 103b: lower piece , 105: floor base material, 107: gap, 110: floor surface, 120: support, 122: installation Part, 124 strut, 126: floor support part

Claims (4)

It is composed of a wood core material and wood fiber boards laminated on both upper and lower surfaces of the core material, provided with a male fruit on two adjacent sides of the wooden core material, a female fruit is formed on the remaining two sides, The length to the tip of the lower piece of the female fruit is two wood composites for double floors formed larger than the length to the tip of the upper piece of the female fruit. In the joined wood composite that is formed by joining together, and only the four corners are the mounting parts of the support,
A joining wood composite material, wherein a reinforcing plate having a width covering the short side of the adjacent wood composite material and covering the real joint portion is bonded to the lower surface of the real joint portion . On the lower surface side of the wood composite material at the side where the male fruit is formed, there is a lower surface stepped portion to which the lower surface side wood fiber board and a part of the wooden core material are cut in a step shape and the lower piece of the female fruit is attached. Formed,
On the upper surface side of the wood composite material, a part of the upper surface side wood fiber board and the wood core material is cut into a step shape, and an upper surface stepped cut portion to which the upper piece of the female is attached is formed,
Between the upper surface stepped cut portion and the lower surface stepped cut portion, an insertion convex portion that is fitted into a female groove is formed, and the length of the upper piece extends from the cut end of the male upper surface stepped cut portion. Formed longer than the length up to the tip of the insertion protrusion, and
The length of the lower piece, which is the length from the groove bottom to the tip of the groove of the female fruit, is the length of the bottom stepped cut portion that is the length from the tip of the insertion convex portion to the cut end. The length of the insertion protrusion, which is the length from the tip of the insertion protrusion to the cutting end, is subtracted from the length of the upper piece, which is the length from the groove bottom to the tip of the groove . The bonded wood composite material according to claim 1, wherein the bonded wood composite material is formed shorter than a sum of the difference. A positioning member is provided on the lower surface on the short side where the female body is provided at a position starting from a position 3/8 to 5/8 of the mounting width of the floor support portion of the support from the tip of the lower piece. The bonded wood composite material according to claim 2, wherein the bonded wood composite material is used. A plurality of support tools erected on the floor according to the four corners of the bonded wood composite material according to any one of claims 1 to 3,
A double floor structure comprising a bonded wood composite material laid on the support and having adjacent sides joined together.