Metal fixture for ceiling backing material and fixation structure for ceiling backing material

Abstract

To provide a metal fixture for ceiling backing material and a fixation structure for ceiling backing material that can easily and securely fix a ceiling backing material, supported crossing a horizontally suspended ceiling backing material, thereto.SOLUTION: A metal fixture 10 consisting of a first side plate part 11 with guide parts 13, 14, capable of engaging by bending from above and below, at upper and lower parts, and a second side plate part 12 with an upper blade part 12b and a lower blade part 12c at upper and lower parts in a direction orthogonal to the first side plate part 11 is used, and the metal fixture 10 is arranged at intersections of a ceiling joist receiver 2 suspended from a ceiling slab and ceiling joists 3, 4. With the guide parts 13, 14 bent from above and below to engage with the ceiling joist receiver 2, the first side plate part 11 is fixed to a side face of the ceiling joist receiver 2 with a screw 16, and the upper blade part 12b and the lower blade part 12c of the second side plate part 12 are fixed to side faces of the ceiling joists 3, 4.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a fixing fitting for a ceiling base material in a building and a fixing structure for a ceiling base material using the fixing fitting.

Background Art

[0002] FIG. 11 shows a structure in which, as a ceiling base material in a building, two upper and lower edge members 3 and 4 horizontally arranged in a direction orthogonal to a soffit support 2 horizontally suspended from a ceiling slab of the building via a suspension bolt 1 are supported. Conventionally, with respect to the soffit support 2 suspended from the ceiling slab of the building, the edge members 3 and 4 are aligned, and in this state, screw holes 5 are drilled from above and below at specific locations of the edge members 3 and 4, and a tool 6 is inserted, and the edge members 3 and 4 are fixed to the soffit support 2 with screws.

[0003] However, the above conventional method has poor workability. In particular, the upper surface of the upper edge member 3 is difficult to visually observe, and for this reason, it is difficult to accurately position and drill the screw holes 5, and if the screw holes 5 are displaced and the screws cannot be fixed to the soffit support 2, the edge member has to be replaced with another one. Since a large number of soffit supports and edge members have to be used for the construction of the ceiling base, and also the construction time cannot be much, the deterioration of workability and the waste of materials have been a problem at the site.

[0004] Regarding the fixing structure of the ceiling base material in a building, various proposals have been made conventionally. For example, Patent Document 1 discloses a structure including a first fitting fixed to a soffit support and a second fitting fixed to an edge member, and the second fitting is fixed across the first fitting. Also, Patent Documents 2 and 3 disclose a structure having a locking portion that locks and supports an edge member having a U-shaped cross section from the inside at the lower end of a clip attached so as to straddle the soffit support from above.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

[0006] However, since the reinforcing fitting of Patent Document 1 uses a plurality of fittings, the workability during installation is poor, and problems such as some fittings falling during installation are likely to occur. The clips of Patent Documents 2 and 3 can be applied to the edge of a cross-section U-shaped eaves base material, but there is a limitation that they cannot be applied to other eaves base materials, for example, the edge of an angle pipe shape.

[0007] The present invention has been made in view of the above circumstances, and an object thereof is to provide a fixing fitting for an eaves base material and a fixing structure for an eaves base material that can easily and surely fix an eaves base material supported horizontally and intersecting with a horizontally suspended eaves base material. [Means for Solving the Problems]

[0008] In order to solve the above problems, the fixing fitting for an eaves base material according to the present invention is a fixing fitting for fixing and suspending a second eaves base material arranged horizontally and intersecting with a first eaves base material suspended horizontally from a ceiling slab of a building, The first side plate portion is provided with upper and lower guide portions that can be bent and engaged with the first ceiling base material from above and below. The upper and lower guide portions are bent and engaged with the edge receiver from above and below, and can be arranged at the intersection position with the second ceiling base material in a state of being in contact with the side surface of the first ceiling base material. The second side plate portion is integrally formed with the first side plate portion, has blade portions extending in the vertical direction along the side surfaces of the second ceiling base material, and can be arranged at the intersection position with the first ceiling base material in a state of being in contact with the side surfaces of the second ceiling base material. The first side plate portion and the second side plate portion can be fixed to the side surface of the first ceiling base material and the side surfaces of the second ceiling base material by screws or bolts in a state of being arranged at the intersection position of the first ceiling base material and the second ceiling base material. This is the first feature.

[0009] The fixing bracket for the ceiling base material according to the present invention is a fixing bracket for fixing and suspending a plurality of second ceiling base materials arranged above and below the first ceiling base material in a horizontal and intersecting direction with respect to the first ceiling base material horizontally suspended from the ceiling slab of a building, The first side plate portion is provided with upper and lower guide portions that can be bent and engaged with the first ceiling base material from above and below. The upper and lower guide portions are bent and engaged with the first ceiling base material from above and below, and can be arranged at the intersection position with the plurality of upper and lower second ceiling base materials in a state of being in contact with the side surface of the first ceiling base material. The second side plate portion is integrally formed with the first side plate portion, has blade portions extending in the vertical direction along the side surfaces of the plurality of upper and lower second ceiling base materials, and can be arranged at the intersection position with the first ceiling base material in a state of being in contact with the side surfaces of the plurality of upper and lower second ceiling base materials. The first side plate portion and the second side plate portion can be fixed to the side surface of the first ceiling base material and the side surfaces of the plurality of upper and lower second ceiling base materials respectively by screws or bolts in a state of being arranged at the intersection position of the first ceiling base material and the plurality of upper and lower second ceiling base materials. This is the second feature.

[0010] The fixing bracket according to the present invention is A third feature is that the upper and lower guide portions are provided with bent portions that can be bent vertically from the side surface of the first ceiling base material to the upper and lower surfaces and then to the other side surface.

[0011] The fixing fitting according to the present invention is A fourth feature is that the first ceiling base material has a U-shaped or C-shaped cross-sectional shape, and the first side plate portion has engaging portions that engage with the upper and lower ends of the upper and lower flanges of the first ceiling base material or the opposing side surfaces at the tips of the upper and lower guide portions.

[0012] The fixing structure of the ceiling base material according to the present invention is A fixing structure of a ceiling base material that fixes and suspends a second ceiling base material disposed horizontally and intersecting with a first ceiling base material suspended horizontally from a ceiling slab of a building by a fixing fitting, The fixing fitting includes upper and lower guide portions that can be bent and engaged with the first ceiling base material from above and below. The upper and lower guide portions are engaged with the first ceiling base material from above and below and are disposed at an intersection position with the second ceiling base material in a state of being in contact with the side surface of the first ceiling base material. It has a first side plate portion that can be disposed, and a second side plate portion that is integral with the first side plate portion and has blade portions extending vertically along the side surface of the second ceiling base material and can be disposed at an intersection position with the first ceiling base material in a state of being in contact with the side surface of the second ceiling base material. A first feature is that when the fixing fitting is disposed at the intersection position of the first ceiling base material and the second ceiling base material, and the first side plate portion and the second side plate portion are respectively in contact with the side surface of the first ceiling base material and the side surface of the second ceiling base material, they are fixed to the side surface of the first ceiling base material and the side surface of the second ceiling base material by screws or bolts, whereby the second ceiling base material is fixed to the first ceiling base material.

[0013] The fixing structure of the ceiling base material according to the present invention is A ceiling base material fixing structure for fixing and supporting a plurality of second ceiling base materials arranged above and below a first ceiling base material suspended horizontally from a ceiling slab of a building, with the second ceiling base materials arranged horizontally and intersecting the first ceiling base material, by means of fixing brackets. The fixing bracket includes upper and lower guide portions that can be bent and engaged with the first ceiling base material from above and below. The upper and lower guide portions are bent and engaged with the first ceiling base material from above and below, and are arranged at the intersection position with the plurality of upper and lower second ceiling base materials in a state of being in contact with the side surface of the first ceiling base material. It also has a first side plate portion. And integrally with the first side plate portion, there are blade portions extending vertically along the side surfaces of the plurality of upper and lower second ceiling base materials, and it has a second side plate portion that can be arranged at the intersection position with the first ceiling base material in a state of being in contact with the side surfaces of the plurality of upper and lower second ceiling base materials. The fixing brackets are arranged at each intersection position between the first ceiling base material and the plurality of upper and lower second ceiling base materials. The first side plate portion and the second side plate portion are respectively in contact with the side surface of the first ceiling base material and the side surfaces of the plurality of upper and lower second ceiling base materials, and are fixed to the side surface of the first ceiling base material and the side surfaces of the plurality of upper and lower second ceiling base materials by screws or bolts. Thus, the plurality of upper and lower second ceiling base materials are fixed to the first ceiling base material, which is the second feature.

[0014] The ceiling base material fixing structure according to the present invention is characterized in that the first ceiling base material is composed of a linear member, and the second ceiling base material is composed of a curved member, which is the third feature.

[0015] The ceiling base material fixing structure according to the present invention is characterized in that the first ceiling base material is composed of a field edge support, and the second ceiling base material is composed of a field edge, which is the fourth feature.

Effects of the Invention

[0016] As described above, according to the present invention, it is possible to easily and surely fix a field edge intersecting with a field edge receiving member suspended from a ceiling slab, and it is possible to efficiently perform the work.

Brief Description of the Drawings

[0017]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Best Mode for Carrying Out the Invention

[0018] Embodiments for carrying out the present invention will be described with reference to the drawings. FIGS. 1 to 6 show an embodiment of the present invention, and in these figures, reference numeral 2 denotes a field edge receiving member, reference numerals 3 and 4 denote field edges, and reference numeral 10 denotes a fixing fitting.

[0019] The fixing fitting 10 is a fitting for fixing the edge supports 3 and 4, which are also ceiling base materials, to the edge receiver 2, which is a ceiling base material. Fig. 1 shows a state where the edge supports 3 and 4 are fixed to the edge receiver 2 using the fixing fitting 10. Fig. 2 shows an overall perspective view of the fixing fitting 10. Fig. 3 shows a plan view (A) and a bottom view (B) of the fixing fitting 10. Fig. 4 shows a front view (A) and a side view (B) of the fixing fitting 10.

[0020] As shown in Fig. 1, a plurality of edge receivers 2, 2 are horizontally suspended from a ceiling slab (not shown) of a building via suspension bolts 1 in parallel with each other at a certain interval. Two edge supports 3, 4 are horizontally arranged above and below each end of the edge receivers 2, 2 in a direction orthogonal to the edge receivers 2, 2, and the two edge supports 3, 4 are supported and fixed to each end of the edge receivers 2, 2 by the fixing fitting 10.

[0021] The edge receiver 2 is made of a lightweight metal material such as a galvanized steel plate and has a U-shaped or C-shaped cross-sectional shape. In the illustrated example, an angle material having an upper flange portion 2b extending horizontally on the upper surface of the vertical portion 2a and a lower flange portion 2c extending horizontally on the lower surface of the vertical portion 2b is used. The edge supports 3, 4 are also made of a lightweight metal material such as a galvanized steel plate and have an L-shaped cross-sectional shape. In the illustrated example, a square pipe material is used.

[0022] The fixing fitting 10 has a shape including a first side plate portion 11 fixed to the edge receiver 2 side and a second side plate portion 12 that is integral with the first side plate portion 11 and is directed at a right angle from the first side plate portion 11 and fixed to the edge supports 3, 4 side.

[0023] The first side plate portion 11 includes a vertical portion 11a having substantially the same height as the vertical portion 2a of the edge receiver 2, an upper flange portion 11b extending from the upper end of the vertical portion 11a in a direction opposite to the direction of the second side plate portion 12, and a lower flange portion 11c extending from the lower end of the vertical portion 11a in a direction opposite to the direction of the second side plate portion 12.

[0024] The upper flange portion 11b is provided with an upper guide portion 13 having a pair of wide engaging portions 13b on the left and right via narrow bending portions 13a. The lower flange portion 11c is provided with a lower guide portion 14 having a pair of wide engaging portions 14b on the left and right via narrow bending portions 14a. The upper guide portion 13 can bend the bending portion 13a downward to engage each engaging portion 13b with the upper flange 2b of the field edge receiver 2, and the lower guide portion 14 can bend the bending portion 14a upward to engage each engaging portion 14b with the lower flange 2b of the field edge receiver 2.

[0025] The second side plate portion 12 includes a vertical portion 12a substantially at the same height as the vertical portion 11a of the first side plate portion 11, an upper wing portion 12b extending upward from the vertical portion 12a, and a lower wing portion 12c extending downward from the vertical portion 12a. The height of the upper wing portion 12b substantially corresponds to the side height of the upper field edge 3, and the height of the lower wing portion 12c substantially corresponds to the side height of the lower field edge 4.

[0026] A plurality of screw holes 15a penetrate in the plate thickness direction at a plurality of locations (two locations in the illustrated example) in the vertical portion 11a of the first side plate portion 11, and a plurality of screw holes 15b penetrate in the plate thickness direction at a plurality of locations (two locations in the illustrated example) in the upper wing portion 12b and the lower wing portion 12c of the second side plate portion 12, respectively.

[0027] Next, the procedure for fixing the field edges 3 and 4 to the end of the field edge receiver 2 suspended by the suspension bolt 1 using the fixing fitting 10 configured as described above will be described below with reference to FIGS. 5 and 6.

[0028] First, for a plurality of edge receivers 2, 2 horizontally suspended by suspension bolts 1, the edge members 3, 4 to be fixed are arranged to be orthogonal, and a fixing fitting 10 is set near the ends of the edge members 3, 4 (Fig. 5(A)). For the edge receiver 2 having a U-shaped cross-section, the fixing fitting 10 sets the first side plate portion 11 having a U-shaped cross-section to cover the vertical portion 2a of the edge receiver 2 from the side over the upper flange 2b and the lower flange 2c, and bends the engaging portion 13b of the upper guide portion 13 downward and the engaging portion 14b of the lower guide portion 14 upward, each by 90 degrees or more (Fig. 5(B)). The bending angles of the engaging portions 13b and 14b may be 90 degrees or less as long as they can engage with the upper flange 2b and the lower flange 2c above and below.

[0029] Thereby, the first side plate portion 11 of the fixing fitting 10 is locked to the edge receiver 2. Since the first side plate portion 11 of the fixing fitting 10 is locked to the edge receiver 2, even in high-place work, the fixing fitting 10 can be surely positioned and arranged at the intersection with the edge member 3 without the fixing fitting 10 falling downward.

[0030] Next, after positioning and arranging the fixing fitting 10 at the intersection with the edge members 3, 4, confirm that the upper blade portion 12a of the second side plate portion 12 is in contact with the side surface of the upper edge member 3 and the lower blade portion 12b of the second side plate portion 12 is in contact with the side surface of the lower edge member 3, and fasten the first side plate portion 11 to the side surface of the edge receiver 2 and the upper blade portion 12b and the lower blade portion 12b of the second side plate portion 12 to the respective side surfaces of the upper and lower edge members 3, 4 with screws 16 (Fig. 5(C)). Of course, screws or the like may be used instead of the screws 16.

[0031] In Fig. 5, the screws 16 for fastening to the edge receiver 2 and the edge member 3 (4) are originally shown by dotted lines inside each, but are shown by solid lines for easy understanding (Fig. 5(C)).

[0032] Thereby, the ends of the upper and lower edge members 3, 4 are fixed to the edge receiver 2 by the fixing fitting 10, and each edge member 3, 4 is supported by each edge receiver 2 (Fig. 6(A)(B)). The same operation is performed for each edge receiver 2.

[0033] The fixing fitting 10 may set the first side plate portion 11 in front of the intersection of the field edges 3 and 4 with respect to the field edge receiver 2. In a state where the upper guide portion 13 and the lower guide portion 14 are bent and engaged, the fixing fitting 10 can be easily positioned at the fixing position by moving it toward the intersection with the field edges 3 and 4 while being guided by the field edge receiver 2 thereafter.

[0034] According to the fixing structure of the present embodiment, the fixing fitting 10 can be easily positioned at the intersection of the field edge receiver 2 and the field edges 3 and 4, and the field edges 3 and 4 can be securely fixed and supported by the field edge receiver 2, so that the ceiling base work and interior work can be efficiently advanced.

[0035] FIG. 7 shows a state in which, after supporting the upper and lower field edges 3 and 4 with respect to the field edge receiver 2 using the fixing fitting 10, a finishing material 20 such as a decorative panel is vertically attached to the side surfaces of the upper and lower field edges 3 and 4. In addition to attaching a finishing material horizontally to the ceiling on the lower surface of the lower field edge 4, as shown in FIG. 7, a finishing material perpendicular to the ceiling can be attached to the side surface together with the upper field edge 3. The structure of FIG. 7 is applicable to cases where indirect lighting is installed.

[0036] FIG. 8 shows a state in which the fixing fitting 10 is used to fixedly support the upper and lower field edges 3' and 4' with a higher curvature on the linear field edge receiver 2'. Since the fixing fitting 10 of the present embodiment sets the first side plate portion 11 at the intersection of the linear field edge receiver 2' (or moves it to the intersection after setting it on the linear field edge receiver 2' for positioning), the fixing operation with the curved upper and lower field edges 3' and 4' can be easily, surely, and efficiently performed. The fixing fitting 10 of the present embodiment also exhibits an effect even when supporting the field edges 3' and 4' to which a curved finishing material is attached on the field edge receiver 2'.

[0037] FIGS. 9 and 10 show a fixing fitting showing the second embodiment of the present invention. In the fixing fitting 10' of the present embodiment, the height of the first side plate portion 11' is lower than the height of the first side plate portion 11 in the fixing fitting 10 shown in FIG. 2, and as shown in FIG. 10(C), it has a shape that fits the field edge receiver 7 made of a square pipe material with a low cross-sectional L shape.

[0038] The fixing fitting 10' shown in Fig. 9 has the same structure and shape as the fixing fitting 10 shown in Fig. 2, except for the dimension of the height of the first side plate portion 11'. The second side plate portion 12 includes an upper flange portion 12b and a lower flange portion 12c, and screw holes 15b are provided in each of them. As shown in Fig. 10, of course, it can be used when fixing either the upper or lower edge (the edge 4 in the illustrated example) to the edge receiver 7.

[0039] The fixing fittings 10 and 10' of the above embodiment include an upper flange portion 12a and a lower flange portion 12b in the second side plate portion 12. However, when fixing only one of the upper and lower edges 3 and 4 to the edge receivers 2 and 7, it may have a shape including only the upper flange portion 12a or only the lower flange portion 12b in the second side plate portion 12.

[0040] The fixing fittings 10 and 10' of the above embodiment have a structure in which the second side plate portion 12 faces the first side plate portions 11 and 11' at a right angle. However, it does not necessarily have to be a right angle, and any shape that matches the intersection angle of the edges 3, 4 (3', 4') with respect to the edge receivers 2, 2' is acceptable.

[0041] In the above embodiment, the fixing fittings 10 and 10' are used for fixing the edges 3, 4 (3', 4') to the edge receivers 2 and 2'. However, the present invention is not limited to this, and it can be used as a fitting for fixing another horizontal member orthogonal to a horizontal member.

Industrial Applicability

[0042] The present invention can be used as a fixing fitting for fixing ceiling base materials to each other, and as a fixing structure for ceiling base materials using the fixing fitting.

Explanation of Reference Numerals

[0043] 1 Hanging bolt 2, 2', 7 Edge receiver (first ceiling base material) 3, 3', 4, 4' Edge (second ceiling base material) 5, 15a, 15b Screw hole 6 Tool 10 Fixing fitting 11 First side plate part 11a Vertical part 11b Upper flange part 11c Lower flange part 12 Second side plate part 12a Upper fin part 12b Lower fin part 13 Upper guide part 13a, 14a Bending part 13b, 14b Locking part 14 Lower guide part 16 Screw

Claims

1. A fixing bracket for fixing and supporting a second ceiling base material arranged horizontally and intersecting a first ceiling base material suspended horizontally from a ceiling slab of a building, A ceiling base material fixing bracket having upper and lower guide portions that can be bent from above and below to engage with the first ceiling base material, a first side panel portion that can be bent from above and below to engage the upper and lower guide portions with the soffit support and can be positioned at an intersection with the second ceiling base material in a state in which it abuts against the side of the first ceiling base material, and a second side panel portion that is integral with the first side panel portion and has a blade portion that extends in the vertical direction along the side of the second ceiling base material and can be positioned at the intersection with the first ceiling base material in a state in which it abuts against the side of the second ceiling base material, and these first side panel portion and second side panel portion can be fixed to the side of the first ceiling base material and the side of the second ceiling base material with screws or bolts when positioned at the intersection of the first ceiling base material and the second ceiling base material.

2. A fixing bracket for fixing and supporting a plurality of second ceiling base materials arranged above and below a first ceiling base material in a direction that is horizontal and intersects the first ceiling base material, the second ceiling base material being suspended horizontally from a ceiling slab of a building; a first side panel portion that is integral with the first side panel portion and has a blade portion extending in the vertical direction along each side of the multiple upper and lower second ceiling substrates and that can be positioned at the intersection with the first ceiling substrate in a state in which it is abutted against the side of the multiple upper and lower second ceiling substrates; and a second side panel portion that is integral with the first side panel portion and has a blade portion extending in the vertical direction along each side of the multiple upper and lower second ceiling substrates and that can be positioned at the intersection with the first ceiling substrate in a state in which it is abutted against the side of the multiple upper and lower second ceiling substrates, and these first side panel portion and second side panel portion can be fixed to the side of the first ceiling substrate and each side of the multiple upper and lower second ceiling substrates with screws or bolts when positioned at the intersection of the first ceiling substrate and the multiple upper and lower second ceiling substrates.

3. A fixing bracket for a ceiling underlayment as described in claim 1 or claim 2, characterized in that the upper and lower guide portions have folding portions that can be folded up and down from the side of the first ceiling underlayment to the other side via the upper and lower surfaces.

4. A fixing bracket for a ceiling underlayment as described in claim 1 or claim 2, characterized in that the first ceiling underlayment has a U-shaped or L-shaped cross-sectional shape, and the first side panel portion has upper and lower engaging portions at the tips of the upper and lower guide portions which engage with the ends or opposing side surfaces of the upper and lower flanges of the first ceiling underlayment.

5. A ceiling base material fixing structure in which a first ceiling base material is suspended horizontally from a ceiling slab of a building, and a second ceiling base material is arranged horizontally and intersecting the first ceiling base material by fixing brackets to support the first ceiling base material, The fixing bracket has upper and lower guide portions which can be bent and engaged with the first ceiling base material from above and below, a first side plate portion which engages the upper and lower guide portions with the first ceiling base material from above and below and can be arranged at an intersection with the second ceiling base material in a state of abutting against a side surface of the first ceiling base material, and a second side plate portion which is integral with the first side plate portion and has a blade portion which extends in the vertical direction along the side surface of the second ceiling base material and can be arranged at an intersection with the first ceiling base material in a state of abutting against the side surface of the second ceiling base material, A fixing structure for a ceiling base material, characterized in that the fixing bracket is positioned at the intersection of the first ceiling base material and the second ceiling base material, and the first side panel portion and the second side panel portion are abutted against the side surfaces of the first ceiling base material and the second ceiling base material, respectively, and fixed to the side surfaces of the first ceiling base material and the second ceiling base material with screws or bolts, thereby fixing the second ceiling base material to the first ceiling base material.

6. A ceiling base material fixing structure in which a first ceiling base material is suspended horizontally from a ceiling slab of a building, and a plurality of second ceiling base materials are fixed and supported above and below the first ceiling base material in a direction that is horizontal and intersects the first ceiling base material by fixing brackets, The fixing bracket has upper and lower guide portions which can be bent and engaged with the first ceiling base material from above and below, a first side plate portion which allows the upper and lower guide portions to be bent and engaged with the first ceiling base material from above and below and which can be arranged at an intersection with the upper and lower second ceiling base materials in a state of abutting against a side surface of the first ceiling base material, and a second side plate portion which is integral with the first side plate portion and has blade portions which extend up and down along each side surface of the upper and lower second ceiling base materials and which can be arranged at an intersection with the first ceiling base material in a state of abutting against the side surfaces of the upper and lower second ceiling base materials, A ceiling base fixing structure characterized in that the fixing brackets are arranged at each intersection of the first ceiling base material and the multiple upper and lower second ceiling base materials, and the first side panel portion and the second side panel portion are abutted against the side surfaces of the first ceiling base material and the multiple upper and lower second ceiling base materials, respectively, and fixed to the side surfaces of the first ceiling base material and the multiple upper and lower second ceiling base materials with screws or bolts, thereby fixing the multiple upper and lower second ceiling base materials to the first ceiling base material.

7. 7. A ceiling underlayment fixing structure according to claim 5 or claim 6, characterized in that the first ceiling underlayment is made of a straight member, and the second ceiling underlayment is made of a curved member.

8. 7. A ceiling underlayment fixing structure according to claim 5 or claim 6, characterized in that the first ceiling underlayment is made of a joist support and the second ceiling underlayment is made of a joist.

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