JP2024055672A - Combined beams and combined beam fixing structures - Google Patents

Abstract

To maintain, in a combination beam consisting of a plurality of square timbers stacked in a front-back direction, an initial strength of the combination beam without each square timber displacing in vertical, front-back, or left-right directions even when an external force repeatedly acts on the combination beam fixed to a column or another beam.SOLUTION: In a combination beam 2 where square timbers 3 and 4 are stacked in a front-back direction, drift pins 21a, 21b to 24a, 24b are inserted across the square timbers 3 and 4 to prevent the square timbers 3 and 4 from being displaced from each other in vertical and horizontal directions, and at each end of a longitudinal direction of the square timbers 3 and 4, fixing brackets 11 to 18 are fixed by fixing pins 31a, 31b to 38a, 38b, and the fixing brackets 11 to 18 are fixed to columns 5 and 6 by fixing bolts 41a, 41b to 48a, 48b and nuts 41an, 41bn to 48an, 48bn.SELECTED DRAWING: Figure 1

Description

The present invention relates to a combination beam made by combining multiple wooden beams into one beam, and a fixing structure for the combination beam.

The beams of wooden buildings are made of square timber with a rectangular cross section (a cross section perpendicular to the axial direction of the material), but as the building becomes larger, the load acting on the beams also increases, so beams with a larger cross-sectional area are required to be stronger.
In this case, since it is difficult to obtain square timber with a large cross-sectional area, a beam made by combining (stacking) multiple square timbers with a smaller cross-sectional area (hereinafter referred to as a "combined beam") is often used.
For example, Patent Document 1 (JP 2012-82609 A) discloses a cross member (beam) made by stacking three components processed from small diameter timber or thinned timber, each with a roughly square cross section and each side measuring approximately 90 mm, vertically, and joining them with nuts and bolts passing through them.
Like the cross member disclosed in Patent Document 1, many composite beams are made by stacking square timbers vertically to give a vertically long rectangular cross section.

Here, when constructing a composite beam using square timbers with a rectangular cross section, stacking them vertically not only makes the composite beam taller and the building correspondingly taller, but also creates problems such as the square timbers shifting horizontally and the composite beam being easily deformed by horizontal forces.
For this reason, when constructing a composite beam using rectangular timbers as described above, it is conceivable to stack the timbers in the front-to-back direction (left-to-right direction) rather than the up-to-down direction.
However, when a combined beam is formed by stacking multiple rectangular timbers in the front-to-back (left-to-right) direction and fixing the stacked timbers with bolts and nuts as in Patent Document 1, there is a gap between the bolt and the bolt hole in the timbers. Therefore, when a vertical downward load acts on the combined beam, the stacked timbers will shift from one another and will not deform as a unit, resulting in a problem that the combined beam does not have sufficient strength.

In this regard, Patent Document 2 (JP Patent Publication 2003-239453 A) discloses a structural composite material (beam) in which a flat core material made of steel plate is sandwiched between a pair of laminated wood pieces of medium or small cross section having a rectangular cross section, and the core material and the laminated wood pieces have connecting holes penetrating both materials formed in advance at appropriate intervals so that they match each other, bolts or drift pins are inserted into these connecting holes, and nuts are fastened to the bolts to join the core material and the laminated wood pieces.
However, the structural composite material (beam) of Patent Document 2 uses a core material that is arranged continuously over the entire length of the beam and extends toward the column at its end. This not only complicates and increases manufacturing costs, but also increases the weight of the structural composite material due to the core material made of steel plate. Combined with the core material extending from the end of the structural composite material, this results in a problem of extremely heavy workload for transporting the structural composite material and assembling it to the column.

Incidentally, Patent Document 3 (JP 2021-80753 A) discloses a joining member in which a first piece of wood having a first through hole, an intermediate piece of wood having an intermediate through hole, and a second piece of wood having a second through hole are stacked so that the through holes are aligned, and a drift pin having a press-in portion and a reduced diameter portion is pressed into the first through hole, the intermediate through hole, and the second through hole to join the first piece of wood, the intermediate piece of wood, and the second piece of wood.
However, the joining member disclosed in Patent Document 3 is not a combined beam in which multiple rectangular timbers are stacked in the front-to-back direction (left-to-right direction). Even if the joining member of Patent Document 3 is applied to a combined beam in which multiple rectangular timbers are joined, the contacting surfaces (facing surfaces) of the timbers joined by the drift pins are likely to separate, and when an external force is repeatedly applied to the combined beam in this state in which the surfaces of each timber have separated and gaps have formed, the gaps between each timber will become larger, and gaps will form between the drift pins and the through holes of each timber. As a result, the timbers will not deform as a unit, and the initial strength of the combined beam will not be maintained.

JP 2012-82609 A JP 2003-239453 A JP 2021-80753 A

The problem that this invention aims to solve is to make a combination beam consisting of multiple wooden timbers with rectangular cross sections stacked in the front-to-back (left-to-right) direction, without placing any other members between adjacent timbers, and to make it possible to maintain the initial strength of the combination beam even when external forces are repeatedly applied to the combination beam fixed to a pillar or other beam without the individual timbers shifting in the up-down, front-to-back, or left-to-right directions.

The invention of claim 1 solves the above problems by providing a combination beam in which multiple wooden square timbers with rectangular cross sections are stacked in the front-to-back direction so that the opposing faces of adjacent square timbers are in contact with each other, and multiple drift pins are inserted across each square timber that makes up the combination beam to prevent the square timbers from shifting relative to each other in the up-down and left-to-right directions, and the combination beam is provided with a slip prevention means that prevents the square timbers from shifting relative to each other in the front-to-back direction even if an external force is repeatedly applied to the combination beam fixed to a pillar or other beam.

The invention of claim 2 solves the above problem by providing a combination beam in which the slip prevention means comprises fixing brackets for fixing the combination beam to the pillar or other beam, a first fixing bracket mounting member for mounting the fixing brackets to each longitudinal end of the front and rear square timbers, and a second fixing bracket mounting member for mounting the fixing brackets to the pillar or other beam.

The invention of claim 3 solves the above problem by providing a combination beam in which the first fixing bracket mounting member is a fixing pin that passes through the fixing bracket fitted into the end of each of the front and rear square timbers, and the second fixing bracket mounting member is the column or other beam, a fixing bolt that passes through the fixing bracket, and a nut that screws onto the fixing bolt.

The invention of claim 4 solves the above problem by providing a combination beam in which the slippage prevention means is a connecting bolt inserted across each of the beams and a nut screwed onto the connecting bolt.

The invention of claim 5 is a fixing structure for a combination beam in which a combination beam is formed by stacking a number of wooden square timbers with rectangular cross sections in the front-to-back direction so that the opposing faces of adjacent square timbers are in contact with each other, and the combination beam is fixed to a column or other beam by a fixing bracket so that the square timbers do not shift relative to each other in the up-down and left-to-right directions, and the combination beam is fixed to the column or other beam by a fixing bracket so that the square timbers do not shift relative to each other in the front-to-back direction even if an external force is repeatedly applied to the combination beam, and one end of the fixing bracket is attached to each of the longitudinal ends of the front and back square timbers of the respective square timbers by a first fixing bracket mounting member, and the other end of the fixing bracket is attached to the column or other beam by a second fixing bracket mounting member, thereby providing a fixing structure for a combination beam that solves the above-mentioned problem.

The invention of claim 6 solves the above problem by providing a fixing structure for a combination beam in which a connecting bolt is inserted across each of the square beams and a nut is screwed onto the connecting bolt so that the square beams do not shift relative to each other in the forward and backward directions even if an external force is repeatedly applied to the combination beam.

The invention of claim 7 solves the above problem by providing a combined beam fixing structure in which the first fixing bracket mounting member is a fixing pin that passes through one end of the fixing bracket fitted into the end of each of the front and rear square timbers, and the second fixing bracket mounting member is a fixing bolt that passes through the column or other beam and the other end of the fixing bracket, and a nut that screws onto the fixing bolt.

In the combined beam of the invention described in claim 1, multiple drift pins are inserted across each of the square members to prevent the square members from shifting in the up-down and left-right directions relative to each other, and anti-slip means are provided to prevent the square members from shifting in the front-back direction relative to each other. This has the effect that even if an external force is repeatedly applied to a combined beam fixed to a pillar or other beam, the gaps between the square members do not become larger or gaps do not appear between the drift pins and the square members, but the square members deform as a unit, and the initial strength of the combined beam can be maintained.

The combined beam of the invention described in claim 2 has the further effect that the combined beam is fixed to a column or other beam by the fixing bracket, the first fixing bracket mounting member, and the second fixing bracket mounting member, so that the individual square members do not shift relative to each other in the forward and backward directions.

The combined beam of the invention described in claim 3 has the further effect that the combined beam is fixed to a column or other beam by fixing brackets, fixing pins, fixing bolts and nuts, so that the individual square members do not shift relative to each other in the forward and backward directions.

The combined beam of the invention described in claim 4 has the further effect that the beams are connected to each other by connecting bolts inserted across each beam and nuts screwed onto the connecting bolts, preventing the beams from shifting relative to each other in the forward and backward directions.

In the fixed structure of the combined beam of the invention described in claim 5, a plurality of drift pins are inserted across each of the square members to prevent the square members from shifting in the up-down and left-right directions relative to each other, and a slip prevention means is provided to prevent the square members from shifting in the front-back direction relative to each other. Therefore, even if an external force is repeatedly applied to a combined beam fixed to a pillar or other beam, the gaps between the square members do not become larger or gaps do not appear between the drift pins and the square members, and each square member deforms as a unit, thereby achieving the effect of maintaining the initial strength of the fixed structure of the combined beam.

The fixing structure of the combined beam of the invention described in claim 6 has the further effect that the beams are connected to each other by connecting bolts inserted across each beam and nuts screwed onto the connecting bolts, preventing them from shifting relative to each other in the forward and backward directions.

The fixing structure of the combined beam of the invention described in claim 7 has the effect of fixing the combined beam to a column or other beam with fixing brackets, fixing pins, fixing bolts and nuts, preventing each square member from shifting relative to each other in the forward and backward directions.

FIG. 2 is a perspective view of the combined beam of the present invention fixed to a column; 2 is a front view and a rear view of the combination beam in the fixed state shown in FIG. 1 . 2A and 2B are a plan view and a bottom view of the combination beam in the fixed state shown in FIG. 1 . 2 is an enlarged left side view and an enlarged right side view of the combination beam in the fixed state shown in FIG. 1 . 3 is an enlarged cross-sectional view taken along line AA and line BB in FIG. 2. 4 is an enlarged cross-sectional view taken along the line CC and an enlarged cross-sectional view taken along the line DD in FIG. FIG. 2 is an exploded perspective view of the combination beam in the fixed state shown in FIG. 1 . This is an oblique view of fixing brackets 11 (12), 13 (14), 15 (16), and 17 (18). This is a front view and a rear view of a combination beam in which two square timbers are stacked in the front-to-back direction, pins are inserted through them, and they are connected with connecting bolts. 10 is a plan view and an enlarged cross-sectional view taken along the line E-E of the combination beam shown in FIG. 9.

[Configuration of combined beam and its fixing structure]
FIG. 1 is a perspective view of the state in which the combined beam of the present invention is fixed to a column (hereinafter referred to as the "combined beam fixed state"); FIG. 2(a) is a front view of the combined beam fixed state shown in FIG. 1; FIG. 2(b) is a back view of the combined beam fixed state shown in FIG. 1; FIG. 3(a) is a plan view of the combined beam fixed state shown in FIG. 1; FIG. 3(b) is a bottom view of the combined beam fixed state shown in FIG. 1; FIG. 4(a) is an enlarged left side view of the combined beam fixed state shown in FIG. 1; FIG. 4(b) is an enlarged right side view of the combined beam fixed state shown in FIG. 1; FIG. 5(a) is an enlarged cross-sectional view taken along A-A in FIG. 2(a); FIG. 5(b) is an enlarged cross-sectional view taken along B-B in FIG. 2(a); FIG. 6(a) is an enlarged cross-sectional view taken along C-C in FIG. 3(a); FIG. 6(b) is an enlarged cross-sectional view taken along D-D in FIG. 3(b); and FIG. 7 is an exploded perspective view of the combined beam fixed state shown in FIG. 1.
In the figure, 1 is the fixed structure of the combined beam, 2 is the combined beam, 3 and 4 are square timbers, 3m1, 3m2, 4m1, and 4m2 are grooves, 5 and 6 are columns, 5h1, 5h2, 5h3, 5h4, 6h5, 6h6, 6h7, and 6h8 are recesses, 5s1a, 5s1b, 5s2a, 5s2b, 5s3a, 5s3b, 5s4a, 5s4b, 6s5a, 6s5b, 6s6a, 6s6b, 6s7a, 6s7b, 6s7c, 6s7d, 6s7e, 6s7f, 6s7g, 6s7h, 6s7h, 6s7h, 6s7i, 6s7j, 6s7p ... s8a and 6s8b are through holes, 11, 12, 13, 14, 15, 16, 17, and 18 are fixing brackets, 21a, 21b, 22a, 22b, 23a, 23b, 24a, and 24b are drift pins, 31a, 31b, 32a, 32b, 33a, 34b, 35a, 35b, 36a, 36b, 37a, 37b, 38a, and 38b are fixing pins, 41a, 41b, 42a, 42b, and 4 3a, 44b, 45a, 45b, 46a, 46b, 47a, 47b, 48a, 48b are fixing bolts, 41an, 41bn, 42an, 42bn, 43an, 44bn, 45an, 45bn, 46an, 46bn, 47an, 47bn, 48an, 48bn are nuts, h21a, h21b, h22a, h22b, h23a, h23b, h24a, h24b, h21a', h21b', h22a', h22b', h23a', h23b', h24a', h24b' are pin holes, h31a, h31b, h32a, h32b, h33a, h34b, h35a, h35b, h36a, h36b, h37a, h37b, h38a, h38b are pin holes, and in each figure, X is the left-right direction, Y is the front-back direction, and Z is the up-down direction.
As shown in FIG. 1, the combined beam fixing structure 1 comprises a combined beam 2, columns 5 and 6, fixing brackets 11 to 18 for fixing the combined beam 2 to the columns 5 and 6, and the like.

[Combined beams and columns]
The combined beam 2 is made up of square timbers 3 and 4 stacked in the front-to-back direction (Y direction), and the square timbers 3 and 4 are made of wooden materials such as cypress (hinoki), hiba (hiba leaves), cedar (sugi), Japanese pine (Japanese pine, larch, Yezo spruce, and Todomatsu), Douglas fir, and European red pine.
The square timbers 3, 4 have a rectangular cross section with cross-sectional dimensions (short side x long side) of 45 to 240 mm x 105 to 450 mm, and a height of approximately 1 m to 9 m.
In this embodiment, the vertical cross-sectional dimensions (short side x long side) of the square timbers 3, 4 are both 105 mm x 330 mm, and the length is approximately 4 m.
The front side beam 3 has, at its left end in the longitudinal direction (X direction), a groove 3m1 extending in the vertical direction (Z direction), and pin holes h31a, h31b, h32a, and h32b passing through groove 3m1 and penetrating the beam 3 in the Y direction, and, at its right end in the longitudinal direction (X direction), a groove 3m2 extending in the vertical direction (Z direction), and pin holes h35a, h35b, h36a, and h36b passing through groove 3m2 and penetrating the beam 3 in the front-to-rear direction (Y direction).
In addition, the square timber 3 is provided with two upper and lower pin holes h21a and h21b, pin holes h22a and h22b, pin holes h23a and h23b, and pin holes h24a and h24b, which penetrate the square timber 3 in the front-to-back direction except at both ends, at approximately equal intervals in the left-to-right direction.
As with the square timber 3, the rear square timber 4 has, at its left end in the longitudinal direction (X direction), a groove 4m1 extending in the vertical direction and pin holes h33a, h33b, h34a, and h34b which pass through the groove 4m1 and pierce the square timber 4 in the front-to-rear direction, and at its right end in the longitudinal direction (X direction), a groove 4m2 extending in the vertical direction and pin holes h37a, h37b, h38a, and h38b which pass through the groove 4m2 and pierce the square timber 4 in the front-to-rear direction.
In addition, like the square timber 3, the square timber 4 is also provided with two upper and lower pin holes h21a' and h21b', pin holes h22a' and h22b', pin holes h23a' and h23b', and pin holes h24a' and h24b', which penetrate the square timber 4 in the front-to-back direction except at both ends, and are provided at approximately equal intervals in the left-to-right direction.
As a result, the shape, dimensions, and structure of timber 3 and timber 4 are the same, and when timber 3 and timber 4 are stacked in the front-to-back direction, pin holes h21a, h21b and pin holes h21a', h21b', pin holes h22a, h22b and pin holes h22a', h22b', pin holes h23a, h23b and pin holes h23a', h23b', and pin holes h24a, h24b and pin holes h24a', h24b' coincide.

Like the timbers 3, 4, the pillars 5, 6 are made of wooden materials such as cypress, hiba, Japanese cedar, Japanese pine (Japanese pine, larch, Yezo spruce, and Todo fir), Douglas fir, and European red pine.
In the left-side pillar 5, rectangular recesses 5h1, 5h2 are provided on the right side of the pillar 5 where the left end face of the square timber 3 is placed, and rectangular recesses 5h3, 5h4 are provided on the part where the left end face of the square timber 4 is placed.
Through holes 5s1a, 5s1b, through holes 5s2a, 5s2b, through holes 5s3a, 5s3b, and through holes 5s4a, 5s4b are provided from the left side surface of the pillar 5 to each of the recesses 5h1, 5h2, 5h3, and 5h4, respectively.
Similarly, in the right-side pillar 6, rectangular recesses 6h5 and 6h6 are provided on the left side of the pillar 6 where the right end face of the square timber 3 is placed, and rectangular recesses 6h7 and 6h8 are provided on the part where the right end face of the square timber 4 is placed.
Further, through holes 6s5a, 6s5b, through holes 6s6a, 6s6b, through holes 6s7a, 6s7b, and through holes 6s8a, 6s8b are provided from the right side surface of the pillar 6 to each of the recesses 6h5, 6h6, 6h7, and 6h8, respectively.

[Fixing bracket, drift pin, fixing pin, fixing bolt]
The fixing brackets 11 to 18 are used to fix the combination beam 2 to the columns 5 and 6, and are made of an L-shaped metal plate, for example, an alloy-plated steel plate.
Of the fixing brackets 11 to 18, fixing bracket 11 and fixing bracket 12, fixing bracket 13 and fixing bracket 14, fixing bracket 15 and fixing bracket 16, and fixing bracket 17 and fixing bracket 18 are all identical, with fixing bracket 15 (16) being fixing bracket 13 (14) rotated 180 degrees horizontally, and fixing bracket 17 (18) being fixing bracket 11 (12) rotated 180 degrees horizontally.
That is, the fixing brackets 11, 12, 17, and 18 are the same, and the fixing brackets 13, 14, 15, and 16 are the same.
8(a), (b), (c), and (d) are perspective views of the fixing brackets 11 (12), 13 (14), 15 (16), and 17 (18), respectively.
In the figure, 11a, 13a, 15a, and 17a are groove insertion portions, 11b, 13b, 15b, and 17b are column abutment portions, 11k, 13k, 15k, and 17k are notches, 11p, 13p, 15p, and 17p are holes, 11q, 13q, 15q, and 17q are upper holes, and 11r, 13r, 15r, and 17r are lower holes, and the symbols of the fixing brackets 12, 14, 16, and 18 are shown in parentheses.

In the fixing brackets 11 and 13 located on the left pillar 5 side, semi-elliptical notches 11k and 13k are provided in the upper right corner of the groove insertion portions 11a and 13a, holes 11p and 13p are provided in the lower right corner of the groove insertion portions 11a and 13a, and upper holes 11q and 13q and lower holes 11r and 13r are provided in the pillar abutment portions 11b and 13b.
In the fixing bracket 11, the groove insertion portion 11a is the portion that is inserted into the groove 3m1 of the square timber 3, the column abutment portion 11b is the portion that is fitted into the recess 5h1 of the column 5, the notch 11k and the hole 11p are portions through which the fixing pins 31a and 31b are inserted, and the upper hole 11q and the lower hole 11r are portions through which the fixing bolts 41a and 41b are inserted.
In this case, the thickness of the groove insertion portion 11a is the same as the width (length in the Y direction) of the groove 3m1, and the width (length in the Y direction) and height (length in the Z direction) of the pillar abutment portion 11b are the same as the width and height of the recess 5h1.
In the fixing bracket 13, the groove insertion portion 13a is the portion that is inserted into the groove 4m1 of the square timber 4, the column abutment portion 13b is the portion that is fitted into the recess 5h3 of the column 5, the notch 13k and the hole 13p are portions through which the fixing pins 33a and 33b are inserted, and the upper hole 13q and the lower hole 13r are portions through which the fixing bolts 43a and 43b are inserted.
In this case, the thickness of the groove insertion portion 13a is the same as the width (length in the Y direction) of the groove 4m1, and the width (length in the Y direction) and height (length in the Z direction) of the pillar abutment portion 13b are the same as the width and height of the recess 5h3.

In the fixing brackets 15 and 17 located on the right pillar 6 side, semi-elliptical notches 15k and 17k are provided in the upper left part of the groove insertion portions 15a and 17a, holes 15p and 17p are provided in the lower left part of the groove insertion portions 15a and 17a, and upper holes 15q and 17q and lower holes 15r and 17r are provided in the pillar abutment portions 15b and 17b.
In the fixing bracket 15, the groove insertion portion 15a is the portion that is inserted into the groove 3m2 of the square timber 3, the column abutment portion 15b is the portion that is fitted into the recess 6h5 of the column 6, the notch 15k and the hole 15p are portions through which the fixing pins 35a and 35b are inserted, and the upper hole 15q and the lower hole 15r are portions through which the fixing bolts 45a and 45b are inserted.
In this case, the thickness of the groove insertion portion 15a is the same as the width (length in the Y direction) of the groove 3m2, and the width (length in the Y direction) and height (length in the Z direction) of the pillar abutment portion 15b are the same as the width and height of the recess 6h5.
In the fixing bracket 17, the groove insertion portion 17a is the portion that is inserted into the groove 4m2 of the square timber 4, the column abutment portion 17b is the portion that is fitted into the recess 6h7 of the column 6, the notch 17k and the hole 17p are portions through which the fixing pins 37a and 37b are inserted, and the upper hole 17q and the lower hole 17r are portions through which the fixing bolts 47a and 47b are inserted.
In this case, the thickness of the groove insertion portion 17a is the same as the width (length in the Y direction) of the groove 4m2 of the square timber 4, and the width (length in the Y direction) and height (length in the Z direction) of the column abutment portion 17b are the same as the width and height of the recess 6h7.

Similarly to the fixing brackets 11 and 13, the fixing brackets 12 and 14 also have groove insertion portions 12a and 14a (portions inserted into the grooves 3m1 and 4m1), column abutment portions 12b and 14b (portions fitted into the recesses 5h2 and 5h4 of the column 5), notches 12k and 14k (portions through which the fixing pins 32a and 34a are inserted), holes 12p and 14p (portions through which the fixing pins 32b and 34b are inserted), upper holes 12q and 14q (portions through which the fixing pins 32a and 34a are inserted), and The thickness of groove insertion portions 12a, 14a is the same as the width of grooves 3m1, 4m1 (the thickness of groove insertion portions 11a, 13a), and the width and height of column abutment portions 12b, 14b are the same as the width and height of recesses 5h2, 5h4 of column 5 (the width and height of column abutment portions 11b, 13b).
The fixing brackets 16 and 18 also have groove insertion portions 16a and 18a (portions inserted into grooves 3m2 and 4m2), column abutment portions 16b and 18b (portions fitted into recesses 6h6 and 6h8 of column 6), notches 16k and 18k (portions through which fixing pins 36a and 38a are inserted), holes 16p and 18p (portions through which fixing pins 36b and 38b are inserted), upper holes 16q and 18q (portions through which fixing pins 36b and 38b are inserted), and The thickness of groove insertion portions 16a, 18a is the same as the width of grooves 3m2, 4m2 (the thickness of groove insertion portions 15a, 17a), and the width and height of column abutment portions 16b, 18b are the same as the width and height of recesses 6h6, 6h8 of column 6 (the width and height of column abutment portions 15b, 17b).

The drift pins 21a, 21b, 22a, 22b, 23a, 23b, 24a, and 24b have the same shape and dimensions, and are made of carbon steel round bars that have been plated with zinc or the like, with their tips shaped like truncated cones.
The upper and lower drift pins 21a and 21b are inserted into the upper and lower pin holes h21a and 21b of the square timber 3 and the upper and lower pin holes h21a' and h21b' of the square timber 4, the upper and lower drift pins 22a and 22b are inserted into the upper and lower pin holes 22a and 22b of the square timber 3 and the lower pin holes h22a' and h22b' of the square timber 4, the upper and lower drift pins 23a and 23b are inserted into the upper and lower pin holes h23a and 23b of the square timber 3 and the upper and lower pin holes h23a' and h23b' of the square timber 4, and the upper and lower drift pins 24a and 24b are inserted into the upper and lower pin holes h24a and 24b of the square timber 3 and the upper and lower pin holes h24a' and h24b' of the square timber 4.
In this case, the outer diameter of the drift pins 21a etc. is the same as the inner diameter of the pin holes into which the drift pins are inserted.
That is, the outer diameters of the eight drift pins such as drift pin 21a, the inner diameters of the eight pin holes in beam 3 such as pin hole h21a, and the inner diameters of the eight pin holes in beam 4 such as pin hole h21a' are all the same.
The outer diameter of the drift pins 21a etc. is appropriately selected in the range of 8 mm to 30 mm according to the dimensions of the square bars 3, 4, and in this embodiment, the outer diameter of the drift pins 21a etc. is 15 mm.
In addition, the length of the drift pins 21a etc. is slightly shorter than the length of the combination beam 2 in the front-to-rear direction (Y direction), and in this embodiment, it is 200 mm, which is slightly shorter than the length of the combination beam 2 in the front-to-rear direction (Y direction) of 210 mm.

The fixing pins 31a, 31b, 32a, 32b, 33a, 34b, 35a, 35b, 36a, 36b, 37a, 37b, 38a, and 38b have the same shape and dimensions and are made of carbon steel round bars that have been zinc-plated or the like, and have truncated conical tips.
The fixing pins 31a, 31b, 32a, 32b are respectively inserted into the pin holes h31a, h31b, h32a, h32b on the left side of the beam 3, the fixing pins 33a, 33b, 34a, 34b are respectively inserted into the pin holes h33a, h33b, h34a, h34b on the left side of the beam 4, the fixing pins 35a, 35b, 36a, 36b are respectively inserted into the pin holes h35a, h35b, h36a, h36b on the right side of the beam 3, and the fixing pins 37a, 37b, 38a, 38b are respectively inserted into the pin holes h37a, h37b, h38a, h38b on the right side of the beam 4.
In this case, the outer diameter of the fixing pins 31a etc. is the same as the inner diameter of the pin holes into which the fixing pins are inserted.
That is, the outer diameters of the 16 fixing pins such as fixing pin 31a, the inner diameters of the eight pin holes in square timber 3 such as pin hole h31a, and the inner diameters of the eight pin holes in square timber 4 such as pin hole h33a are all the same.
The outer diameter of the fixing pins 11a etc. is appropriately selected in the range of 8 mm to 30 mm according to the dimensions of the square timbers 3, 4, and in this embodiment, the outer diameter of the fixing pins 31a etc. is 12 mm.
In addition, the length of the drift pins 21a etc. is slightly shorter than the length of the combination beam 2 in the front-to-rear direction (Y direction), and in this embodiment, it is 100 mm, which is slightly shorter than the length of the combination beam 2 in the front-to-rear direction (Y direction) of 105 mm.

The fixing bolts 41a, 41b, 42a, 42b, 43a, 44b, 45a, 45b, 46a, 46b, 47a, 47b, 48a, and 48b have the same shape and dimensions and are hexagonal bolts made of metal such as carbon steel or stainless steel.
The fixing bolts 41a, 41b are inserted into the through holes 5s1a, 5s1b of the pillar 5, the fixing bolts 42a, 42b are inserted into the through holes 5s2a, 5s2b of the pillar 5, the fixing bolts 43a, 43b are inserted into the through holes 5s3a, 5s3b of the pillar 5, and the fixing bolts 44a, 44b are inserted into the through holes 5s4a, 5s4b of the pillar 5.
The fixing bolts 45, 45b are inserted into the through holes 6s5a, 6s5b of the pillar 6, the fixing bolts 46a, 46b are inserted into the through holes 6s6a, 6s5b of the pillar 6, the fixing bolts 47a, 47b are inserted into the through holes 6s7a, 6s7b of the pillar 6, and the fixing bolts 48a, 48b are inserted into the through holes 6s8a, 6s8b of the pillar 6.
The nominal diameter of this fixing bolt 41a is selected appropriately in the range of M8 to M30 according to the dimensions of the pillars 5, 6 and the beams 3, 4, and in this embodiment, the nominal diameter of the fixing bolts 41a etc. is 16 mm.
Furthermore, nuts 41an, 41bn, 42an, 42bn, 43an, 44bn, 45an, 45bn, 46an, 46bn, 47an, 47bn, 48an, and 48bn are hexagonal nuts that screw onto the fixing bolts 41a, 41b, 42a, 42b, 43a, 44b, 45a, 45b, 46a, 46b, 47a, 47b, 48a, and 48b, respectively.

[Method of fixing composite beams to columns]
Next, a method of stacking square timbers 3 and 4 to form a combined beam 2 and fixing it to pillars 5 and 6 will be described.
First, the square timbers 3 and 4 are stacked in the front-to-back direction (Y direction) so that pin holes h21a, h21b, etc. and pin holes h21a', h21b', etc. are aligned, and the drift pins 21a, 21b to 24a, 24b are driven and inserted into the pin holes h21a, h21b to h24a, h24b and the pin holes h21a', h21b' to 24a', h24b' to form the combined beam 2.
In this combined beam 2, the outer diameter of the drift pins 21a, 21b to 24a, and 24b is the same as the inner diameter of the pin holes h21a, h21b to h24a, and h24b and the pin holes h21a', h21b' to 24a', h24b', so that even if an external force is repeatedly applied to the combined beam 2, the square beams 3 and 4 are prevented from shifting relative to each other in the vertical direction (Z direction) and left-right direction (X direction).

Next, on the pillar 5, the pillar abutment portion 11b of the fixing bracket 11 is placed (fitted) into the recess 5h1 of the pillar 5, the fixing bolts 41a, 41b are inserted into the through holes 5s1a, 5s1b of the pillar 5 and the upper hole 11q and lower hole 11r of the fixing bracket 11, and nuts 41an, 41bn are screwed into them to fix the fixing bracket 11 to the pillar 5 (recess 5h1).
Similarly, for the other fixing brackets 12, 13, 14, the column abutment portions 12b, 13b, 14b are respectively fitted (fitted) into the recesses 5h2, 5h3, 5h4, the fixing bolts 42a, 42b are inserted into the through holes 5s2a, 5s2b and the upper hole 12q and lower hole 12r of the fixing bracket 12 and nuts 42an, 42bn are screwed into them, the fixing bolts 43a, 43b are inserted into the through holes 5s3a, 5s3b and the upper hole 13q and lower hole 13r of the fixing bracket 13 and nuts 43an, 43bn are screwed into them, and the fixing bolts 44a, 44b are inserted into the through holes 5s4a, 5s4b and the upper hole 14q and lower hole 14r of the fixing bracket 14 and nuts 44an, 44bn are screwed into them, and the fixing brackets 12, 13, 14 are fixed to the column 5 (recesses 5h2, 5h3, 5h4).

For the pillar 6, the pillar abutment portion 51b of the fixing bracket 15 is fitted into the recess 6h5 of the pillar 6, the fixing bolts 45a, 45b are inserted into the through holes 6s5a, 6s5b of the pillar 6 and the upper hole 15q and lower hole 15r of the fixing bracket 15, and nuts 45an, 45bn are screwed into them to fix the fixing bracket 15 to the pillar 6 (recess 6h5).
Similarly, for the other fixing brackets 16, 17, 18, the column abutment portions 16b, 17b, 18b are respectively fitted (fitted) into the recesses 6h6, 6h7, 6h8, the fixing bolts 46a, 46b are inserted into the through holes 6s6a, 6s6b and the upper hole 16q and lower hole 16r of the fixing bracket 16 and nuts 46an, 46bn are screwed into them, the fixing bolts 47a, 47b are inserted into the through holes 6s7a, 6s7b and the upper hole 17q and lower hole 17r of the fixing bracket 17 and nuts 47an, 47bn are screwed into them, and the fixing bolts 48a, 48b are inserted into the through holes 6s8a, 6s8b and the upper hole 18q and lower hole 18r of the fixing bracket 18 and nuts 48an, 48bn are screwed into them, and the fixing brackets 16, 17, 18 are fixed to the column 6 (recesses 6h6, 6h7, 6h8).

Next, the left side of the combined beam 2 is placed against the right side of the column 5, the groove insertion portions 11a, 13a of the fixing members 11, 12 protruding to the right from the right side of the column 5 are inserted into the groove 3m1 of the square timber 3, the pin holes h31a, h31b are aligned with the notch 11k and hole 11p of the fixing member 11, the pin holes h32a, h32b are aligned with the notch 12k and hole 12p of the fixing member 12, and the groove insertion portions 14a, 15a of the fixing members 13, 14 protruding to the right from the right side of the column 5 are inserted into the groove 4m1 of the square timber 4, the pin holes h33a, h33b are aligned with the notch 13k and hole 13p of the fixing member 13, and the pin holes h34a, h34b are aligned with the notch 14k and hole 14p of the fixing member 14.
At the same time, the right side of the combined beam 2 is placed against the left side of the column 6, the groove insertion portions 15a, 16a of the fixing members 15, 16 protruding to the left from the left side of the column 6 are inserted into the groove 3m2 of the square timber 3, the pin holes h35a, h35b are aligned with the notch 15k and hole 15p of the fixing member 15, the pin holes h36a, h36b are aligned with the notch 16k and hole 16 of the fixing member 16, and the groove insertion portions 18a, 18a of the fixing members 17, 18 protruding to the left from the left side of the column 6 are inserted into the groove 4m2 of the square timber 4, the pin holes h37a, h37b are aligned with the notch 17k and hole 17p of the fixing member 17, and the pin holes h38a, h38b are aligned with the notch 18k and hole 18 of the fixing member 18.

In this state, at the left end of the square timber 3 of the combined beam 2, the fixing pins 31a, 31b are driven into the pin holes h31a, h31b and inserted into the pin holes h31a, h31b and the notch 11k and hole 11p of the fixing member 11, and the fixing pins 32a, 32b are driven into the pin holes h32a, h32b and inserted into the pin holes h32a, h32b and the notch 12k and hole 12p of the fixing member 12.
Similarly, at the left end of the square timber 4 of the combined beam 2, the fixing pins 33a, 33b are driven into the pin holes h33a, h33b and inserted into the pin holes h33a, h33b and the notch 13k and hole 13p of the fixing member 13, and the fixing pins 34a, 34b are driven into the pin holes h34a, h34b and inserted into the pin holes h34a, h34b and the notch 14k and hole 14p of the fixing member 14.
In addition, at the right end of the square timber 3 of the combined beam 2, the fixing pins 35a, 35b are driven into the pin holes h35a, h35b and inserted into the pin holes h35a, h35b and the notch 15k and hole 15p of the fixing member 15, and the fixing pins 36a, 36b are driven into the pin holes h36a, h36b and inserted into the pin holes h36a, h36b and the notch 16k and hole 16p of the fixing member 16.
Similarly, at the right end of the square timber 4 of the combined beam 2, fixing pins 37a, 37b are driven into pin holes h37a, h37b and inserted into pin holes h37a, h37b and the notch 17k and hole 17p of the fixing member 17, and fixing pins 38a, 38b are driven into pin holes h38a, h38b and inserted into pin holes h38a, h38b and the notch 18k and hole 18p of the fixing member 18.
In this manner, a fixed structure 1 for a combined beam is formed in which the combined beam 2 is fixed to the columns 5 and 6.

In this case, the left end of the square timber 3 of the combined beam 2 is fixed to the column 5 by the fixing brackets 11 and 12, the fixing pins 31a, 31b, 32a, and 32b, the fixing bolts 41a, 41b, 42a, and 42b, and the nuts 41an, 41bn, 42an, and 42bn, and the left end of the square timber 4 is fixed to the column 5 by the fixing brackets 13 and 14, the fixing pins 33a, 33b, 33a, and 33b, the fixing bolts 43a, 43b, 44a, and 44b, and the nuts 43an, 43bn, 44an, and 44bn. 5, the right end of timber 3 is fixed to pillar 6 by fixing brackets 15, 16, fixing pins 35a, 35b, 36a, 36b, fixing bolts 45a, 45b, 46a, 46b, and nuts 45an, 45bn, 46an, 46bn, and the right end of timber 4 is fixed to pillar 5 by fixing brackets 17, 18, fixing pins 37a, 37b, 38a, 38b, fixing bolts 47a, 47b, 48a, 48b, and nuts 47an, 47bn, 48an, 48bn.
As a result, the fixing brackets 11 to 18 (groove insertion portions 11a to 18a) and the grooves 3m1, 4m1, 3m2, and 4m2 are in face-to-face contact in the fore-and-aft direction (Y direction), so that even if external forces act repeatedly on the combined beam 2, the square timbers 3 and 4 will not shift, at least in the fore-and-aft direction (Y direction).
Therefore, the fixing brackets 11 to 18, fixing pins 31a, 31b to 38a, 38b, fixing bolts 41a, 41b to 48a, 48b, and nuts 41an, 41bn to 48an, 48bn are means for fixing the combined beam 2 to the columns 5 and 6, and also serve as anti-slip means for preventing the square beams 3 and 4 from shifting in the forward/backward direction.

In the above-described combined beam fixing structure 1, the combined beam 2 is fixed to the columns 5 and 6, but the members to which the combined beam 2 is fixed are not limited to the columns 5 and 6, and may be other beams.
When the combination beam 2 is fixed to other beams, the fixing means is the same as the fixing means to the columns 5, 6, such as fixing metal fittings, fixing pins, fixing bolts, etc.
In addition, the combination beam of the present invention includes not only combination beam 2 in which two square timbers 3 and 4 are stacked in the front-to-back direction, but also combination beams in which three or more square timbers are stacked in the front-to-back direction, but in practice combination beams in which two square timbers are stacked are more commonly used.
In addition, in a combined beam made by stacking three or more square timbers in the front-to-back direction, grooves are formed on the left and right ends of each square timber, similar to combined beam 2, and each square timber is fixed to other beams, etc. by fixing brackets, fixing pins, fixing bolts, etc.

[Another example of means for preventing misalignment between the rectangular beams 3 and 4]
Figure 9(a) is a front view of a combination beam in which two square timbers are stacked in the front-to-back direction and connected by a pin inserted through a connecting bolt, Figure 9(b) is a rear view of the combination beam shown in Figure 9(a), Figure 10(a) is a plan view of the combination beam shown in Figure 9, and Figure 10(b) is an enlarged cross-sectional view E-E of Figure 9(a).
In the figure, 2' is a combined beam, 3' and 4' are square timbers, 51, 52, 53, 54, and 55 are connecting bolts, 51n, 52n, 53n, 54n, and 55n are nuts, and s51, s52, s53, s54, s55, s51', s52', s53', s54', and s55' are through holes, and the same symbols are used to refer to the same parts as in the combined beam 2 shown in Figures 1 to 3.
Similar to the combination beam 2, the combination beam 2' is made up of square timbers 3' and 4' stacked in the front-to-back direction (Y direction). The square timbers 3' and 4' have the same rectangular cross section as the square timbers 3 and 4, and are made from the same wooden material as the square timbers 3 and 4.
Similar to the square timber 3, the square timber 3' has two upper and lower pin holes h21a and h21b, pin holes h22a and h22b, pin holes h23a and h23b, and pin holes h24a and h24b that penetrate the square timber 3' in the front-to-back direction except at both ends, and are provided at approximately equal intervals in the left-to-right direction.
Like the square timber 4, the square timber 4' also has two upper and lower pin holes h21a' and h21b', pin holes h22a' and h22b', pin holes h23a' and h23b', and pin holes h24a' and h24b' that penetrate the square timber 4' in the front-to-back direction except at both ends, and are provided at approximately equal intervals in the left-to-right direction.
Then, like the square timber 3 and the square timber 4, the square timber 3' and the square timber 4' are stacked in the front-to-back direction (Y direction) so that the pin holes h21a, h21b, etc. and the pin holes h21a', h21b', etc. are aligned, and the drift pins 21a, 21b to 24a, 24b are driven and inserted into the pin holes h21a, h21b to h24a, h24b and the pin holes h21a', h21b' to 24a', h24b', to form the combined beam 2'.
In this combination beam 2', like the combination beam 2, the outer diameters of the drift pins 21a, 21b to 24a, 24b and the inner diameters of the pin holes h21a, h21b to h24a, h24b and the pin holes h21a', h21b' to 24a', h24b' are the same, so that even if an external force is repeatedly applied to the combination beam 2', the square beams 3' and 4' are not displaced relative to each other in the vertical direction (Z direction) and left-right direction (X direction).

Here, unlike the combination beam 2, the combination beam 2' is equipped with connecting bolts 51, 52, 53, 54, 55, etc., and in the center of the vertical direction (Z direction) of the square timber 3', through holes s51, s52, s53, s54, s55 that penetrate the square timber 3' in the front-to-back direction are provided at approximately equal intervals in the left-to-right direction.
Also in the vertical (Z-direction) central portion of the square 4', through holes s51', s52', s53', s54', and s55' that penetrate the square 4' in the front-rear direction are provided at approximately equal intervals in the left-right direction.
In this case, when the squared beam 3' and the squared beam 4' are stacked in the front-to-rear direction, the through holes s51, s52, s53, s54, and s55 will coincide with the through holes s51', s52', s53', s54', and s55', respectively.

The connecting bolts 51, 52, 53, 54, and 55 have the same shape and dimensions, and are hexagonal bolts made of metal such as carbon steel or stainless steel, similar to the fixing bolt 41a and the like.
The nominal diameter of the connecting bolts 51 to 55 is appropriately selected in the range of M8 to M30 according to the dimensions of the beams 3' and 4', and in this embodiment, the nominal diameter of the connecting bolts 51 to 55 is 16 mm.
Nuts 51n, 52n, 53n, 54n, and 55n are hexagonal nuts that are screwed onto the connecting bolts 51, 52, 53, 54, and 55, respectively.
Then, connecting bolt 51 is inserted into through hole s51 and through hole s51', connecting bolt 52 is inserted into through hole s52 and through hole s52', connecting bolt 53 is inserted into through hole s53 and through hole s53', connecting bolt 54 is inserted into through hole s54 and through hole s54', and connecting bolt 55 is inserted into through hole s55 and through hole s55', and nuts 51n, 52n, 53n, 54n, and 55n are screwed into connecting bolts 51, 52, 53, 54, and 55, respectively.
As a result, even if external forces are repeatedly applied to the combined beam 2', the rectangular beams 3' and 4' will not shift in the front-to-back direction (Y direction), and the connecting bolts 51-55 and nuts 51n-55n act as a means for preventing shifting.

In this case, the combined beam 2' is fixed to the columns 5 and 6 in the same way as the combined beam 2, but the fixing means may be the same fixing brackets, fixing pins, fixing bolts, etc. as the fixing means between the combined beam 2 and the columns 5 and 6, or tenons may be provided at both the left and right ends of the combined beam 2', mortise holes may be provided in the columns 5 and 6, and the tenons of the combined beam 2' may be fitted into the mortise holes in the columns 5 and 6 to fix the combined beam 2' to the columns 5 and 6.
Moreover, the combination beam 2' is not limited to be fixed to the columns 5 and 6, but may be fixed to other beams.
In addition, in the combined beam 2', the positions of the connecting bolts are not limited to being approximately equally spaced in the left-right direction as shown in Figures 9 and 10, but may be located only at the center position in the left-right direction of the combined beam 2' where the square bars 3' and 4' are likely to separate, or may be located so that the spacing becomes narrower toward the center of the combined beam 2' in the left-right direction.
Furthermore, the combination beam 2' is not limited to two square timbers 3' and 4' stacked in the front-to-rear direction, but may be three or more square timbers stacked in the front-to-rear direction.

As described above, the combination beam 2 (2') is formed by stacking the square timbers 3 (3') and 4 (4') in the front-to-back direction (Y direction) and inserting the drift pins 21a, 21b to 24a, 24b into the pin holes h21a, h21b to h24a, h24b and the pin holes h21a', h21b' to 24a', h24b' of the same diameter. Therefore, even if an external force is repeatedly applied to the combination beam 2 (2'), the square timbers 3 (3') and 4 (4') do not shift relative to each other in the up-down direction (Z direction) and left-right direction (X direction). The combination beam 2 is fixed to the columns 5 and 6 by the fixing brackets 11 to 18, the fixing pins 31a, 31b to 38a, 38b, the fixing bolts 41a, 41b to 48a, 48b, and the nuts 41an, 41bn to 48an, 48bn. In the combination beam 2', The square timber 3' and square timber 4' are connected by connecting bolts 51-55 and nuts 51n-55n inserted through the timber 3' and square timber 4', so that even if external forces are repeatedly applied to the combined beam 2 (2'), the square timber 3 (3') and square timber 4 (4') do not shift in the front-to-back direction (Y direction). The square timber 3 (3') and square timber 4 (4') do not become larger in gaps between the square timber 3 (3') and square timber 4 (4') or between the drift pins 21a, 21b-24a, 24b and the pin holes h21a, h21b-h24a, h24b, and between the pin holes h21a', h21b'-24a', h24b'. The square timber 3 (3') and square timber 4 (4') deform as a unit, and the initial strength of the combined beam 2 (2') can be maintained.

The combined beam and combined beam fixing structure of the present invention is a combined beam in which multiple wooden square timbers with rectangular cross sections are stacked in the front-to-back (left-to-right) direction, with no other members between adjacent square timbers. Even if an external force is repeatedly applied to a combined beam fixed to a pillar or other beam, the individual square timbers will not shift in the up-down, front-to-back, or left-to-right directions, and the initial strength of the combined beam can be maintained, making it suitable for use in wooden buildings.

1 Fixed structure of combined beam 2, 2' Combined beam 3, 3', 4, 4' Square timber 3m1, 3m2, 4m1, 4m2 Groove 5, 6 Pillar 5h1, 5h2, 5h3, 5h4, 6h5, 6h6, 6h7, 6h8 Recess 5s1a, 5s1b, 5s2a, 5s2b, 5s3a, 5s3b, 5s4a, 5s4b, 6s5a, 6s5b, 6s6a, 6s6b, 6s7a, 6s7b, 6s8a, 6s8b Through hole 11, 12, 13, 14, 15, 16, 17, 18 Fixing metal fitting 11a, 12a, 13a, 14a, 15a, 16a, 17a, 18a Groove insertion portions 11b, 12b, 13b, 14b, 15b, 16b, 17b, 18b Pillar abutment portions 11k, 12k, 13k, 14k, 15k, 16k, 17k, 18k Notches 11p, 12p, 13p, 14p, 15p, 16p, 17p, 18p Holes 11q, 12q, 13q, 14q, 15q, 16q, 17q, 18q Upper holes 11r, 12r, 13r, 14r, 15r, 16r, 17r, 18r Lower holes 21a, 21b, 22a, 22b, 23a, 23b, 24a, 24b Drift pins 31a, 31b, 32a, 32b, 33a, 34b, 35a, 35b, 36a, 36b, 37a, 37b, 38a, 38b Fixing pins 41a, 41b, 42a, 42b, 43a, 44b, 45a, 45b, 46a, 46b, 47a, 47b, 48a, 48b Fixing bolts 41an, 41bn, 42an, 42bn, 43an, 44bn, 45an, 45bn, 46an, 46bn, 47an, 47bn, 48an, 48bn Nuts 51, 52, 53, 54, 55 Connecting bolts 51n, 52n, 53n, 54n, 55n Nuts h21a, h21b, h22a, h22b, h23a, h23b, h24a, h24b, h21a', h21b', h22a', h22b', h23a', h23b', h24a', h24b' Pin holes h31a, h31b, h32a, h32b, h33a, h34b, h35a, h35b, h36a, h36b, h37a, h37b, h38a, h38b Pin holes s51, s52, s53, s54, s55, s51', s52', s53', s54', s55' Through holes

Claims (7)

A composite beam is made by stacking multiple wooden beams with rectangular cross sections in the front-to-back direction so that the opposing faces of adjacent beams are in contact with each other.
A plurality of drift pins are inserted across each of the square members constituting the combined beam so that the square members do not shift relative to each other in the vertical and horizontal directions.
The combination beam is characterized in that it is provided with a slippage prevention means that prevents each of the square members from slipping relative to each other in the forward/backward direction even if external forces are repeatedly applied to the combination beam fixed to a pillar or other beam. The combination beam according to claim 1, characterized in that the slippage prevention means comprises a fixing bracket for fixing the combination beam to the column or the other beam, a first fixing bracket mounting member for mounting the fixing bracket to each longitudinal end of the front and rear square members of each of the square members, and a second fixing bracket mounting member for mounting the fixing bracket to the column or the other beam. The combination beam according to claim 2, characterized in that the first fixing bracket mounting member is a fixing pin that passes through the fixing bracket fitted into the end of each of the front and rear square timbers, and the second fixing bracket mounting member is a fixing bolt that passes through the pillar or other beam and the fixing bracket, and a nut that screws onto the fixing bolt. The combination beam according to claim 1, characterized in that the slippage prevention means is a connecting bolt inserted across each of the beams and a nut screwed onto the connecting bolt. A fixed structure of a combination beam in which a combination beam is fixed to a column or other beam by stacking multiple wooden beams having a rectangular cross section in the front-to-rear direction so that the opposing faces of adjacent beams are in contact with each other.
A plurality of drift pins are inserted across each of the square members constituting the combined beam so that the square members do not shift relative to each other in the vertical and horizontal directions.
The combination beam is fixed to the column or the other beam by a fixing metal fitting so that the square members do not shift relative to each other in the front-rear direction even if an external force is repeatedly applied to the combination beam,
One end of the fixing bracket is attached to each of the longitudinal ends of the front and rear square timbers of the respective square timbers by a first fixing bracket mounting member,
A fixing structure for a combined beam, characterized in that the other end of the fixing bracket is attached to the column or the other beam by a second fixing bracket mounting member. The fixed structure of the combined beam as described in claim 5, characterized in that the combined beam is further fitted with a connecting bolt that is inserted across each of the square members and a nut that is screwed onto the connecting bolt so that the square members do not shift relative to each other in the forward and backward directions even if an external force is repeatedly applied to the combined beam. The fixing structure of a combined beam as described in claim 5 or claim 6, characterized in that the first fixing bracket mounting member is a fixing pin that passes through one end of the fixing bracket fitted into the end portions of each of the front and rear square timbers, and the second fixing bracket mounting member is a fixing bolt that passes through the column or other beam and the other end of the fixing bracket, and a nut that screws onto the fixing bolt.