Panel fixing structure

Abstract

To fix a panel to a base material without or with a small gap mainly by simply fastening a fastening member from the surface side of the panel.SOLUTION: The present invention relates to a panel fixing structure in which a panel 2 having a face material 4 attached to the surface of a panel frame 3 is fastened and fixed to a base material 5 installed on the back side of the panel 2 using a fastening member 6 from the front side of the panel 2. The fastening member 6 has a first screw portion 11 on the tip side that is screwed into both the base material 5 and the portion of the panel frame 3 on the base material 5 side, and has a second screw portion 12 on the rear end side that is screwed into a portion of the panel frame 3 on the face material 4 side. A pitch 22 of the second screw portion 12 is smaller than a pitch 21 of the first screw portion 11.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] This invention relates to a panel fixing structure.

Background Art

[0002] A panel formed by attaching a facing material to the surface of a panel frame is fastened and fixed to a base material installed on the back side of the panel with a fastening member from the front side of the panel (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In Patent Document 1, instead of directly screwing a fastening member into the base material from the front side of the panel, first, a jig for eliminating gaps is used to temporarily fix and hold the panel and the base material in a state without gaps between them. Then, the panel and the base material fixed and held by the jig for eliminating gaps are fastened and fixed with a fastening member.

[0005] Therefore, a jig for eliminating gaps and a fastening member are separately required, the configuration becomes complicated, and the work takes time.

[0006] Therefore, the main object of the present invention is to contribute to the improvement of the above problems.

Means for Solving the Problems

[0007] Regarding the above problems, the present invention A panel formed by attaching a facing material to the surface of a panel frame is installed on the back side of the panel , a wooden material that is thinner than the surface material of the panel and has the same or lower rigidity as the panel.A panel fixing structure in which the panel is fastened and secured to the base material from the surface side with fastening members, The fastening member is In the state after fastening and securing, To the tip, It protrudes from the aforementioned base material, It has a first threaded portion that screws into both the base material and the portion of the panel frame on the base material side, and a second threaded portion at the rear end that screws into the portion of the panel frame on the surface material side. The pitch of the second threaded portion is smaller than the pitch of the first threaded portion. Furthermore, the first screw portion is screwed into the panel frame by a pitch of 0.5 to 2.0. It is characterized by the following: [Effects of the Invention]

[0008] According to the present invention, the fastening member is screwed in directly from the surface side of the panel with the above configuration. Then, the first threaded portion is made to protrude from the base material, and it is screwed into the panel frame by a pitch of 0.5 to 2.0 mm. Just the panel The wooden material is thinner than the panel's surface material and has the same or lower rigidity as the panel. This allows for fastening to the base material with little to no gaps. [Brief explanation of the drawing]

[0009] [Figure 1] This is a perspective view of a building unit to which the panel fixing structure according to this embodiment is applied. [Figure 2] Figure 1 is a perspective view showing the first panel (interior wall panel) being attached to the side of the building unit. [Figure 3] This is a cross-sectional view of a panel showing the process of attaching an adjacent panel to a connecting portion attached to the back surface of an existing panel using the panel fixing structure of this embodiment. [Figure 4] Figure 3 is a cross-sectional view of the main part showing the state after installation. [Figure 5] (a) to (d) are side views of the fastening members according to Examples 1 to 4. [Figure 6] This is a cross-sectional view of the main part showing the installed state, similar to Figure 4, when using a standard screw. [Figure 7] This is a cross-sectional view illustrating an existing panel fixing structure. [Figure 8]It is a side view of the second-best fastening member used in the embodiment. [Figure 9] (a), (b), and (c) are side views of the fastening members according to Comparative Example 1 to Comparative Example 3, respectively.

Mode for Carrying Out the Invention

[0010] Hereinafter, this embodiment will be described in detail with reference to the drawings. FIGS. 1 to 9 are for explaining this embodiment.

[0011] <Configuration> Hereinafter, the embodiment will be described.

[0012] Hereinafter, for the sake of easy understanding, as an example, the case of fixing the panel 2 as shown in FIG. 2 to the building unit 1 as shown in FIG. 1 will be taken to explain the panel fixing structure. Details of the building unit 1, the panel 2, etc. will be described later.

[0013] Here, the panel fixing structure is such that the panel 2 formed by attaching the facing material 4 to the surface of the panel frame 3 as shown in FIG. 2 is fastened and fixed to the base material 5 installed on the back surface side (upper side in the figure) of the panel 2 from the front surface side (lower side in the figure) of the panel 2 with the fastening member 6 to make it in the state as shown in FIG. 4.

[0014] This panel fixing structure is a structure in which the panel 2 is directly fixed to the base material 5 using the fastening member 6 directly without using auxiliary tools such as a jig for gap elimination.

[0015] As shown in FIG. 2, the panel 2 can be a building material formed by the panel frame 3 and the facing material 4.

[0016] The panel frame 3 is, for example, a rectangular frame member formed by attaching the left and right ends of two parallel horizontal frames 3b of equal length to the upper and lower ends (or the sides of the upper and lower ends) of two parallel vertical frames 3a of equal length. Inside the panel frame 3, one or more horizontal bars 3c of approximately equal length to the horizontal frames 3b may be attached parallel to the horizontal frames 3b with vertical spacing between them. Both ends of the horizontal bars 3c are attached to the opposing sides of the vertical frames 3a. The panel frame 3 is, for example, made of wood.

[0017] The surface of the panel frame 3 is the side facing the front of the panel frame 3, to which the facing material 4 is attached.

[0018] The facing material 4 is a rectangular board that is approximately the same size and shape as the panel frame 3. In the case of building panels 2, the facing material 4 is, for example, gypsum board. Because the facing material 4 is attached integrally, the panel frame 3 is not visible from the surface side.

[0019] The back side of panel 2 is the side opposite to the side to which the facing material 4 of panel frame 3 is attached.

[0020] The base material 5 is positioned on the back side of the panel 2 and is a receiving member for attaching the panel 2. The base material 5 is fixed in place before the panel 2 is attached. For example, in the case of Figure 2, the base material 5 to which the panel 2 is attached is an attachment member 72 fixed to the building unit 1 or the like. The method of attaching the attachment member 72 will be described later. The rigidity of the base material 5 changes depending on how it is attached to the attachment member 72. The lower the rigidity of the base material 5, the more difficult it becomes to attach the panel 2 to the base material 5.

[0021] However, the panel fixing structure of this embodiment is not applied to panel 2 in Figure 2, but rather to another panel 2 adjacent to panel 2 in Figure 2.

[0022] In the panel fixing structure of this embodiment, the base material 5 is assumed to be a wooden member such as plywood. Although the base material 5 made of plywood has the minimum rigidity required as a structural material, it is not as rigid as metal, and it may bend slightly due to external forces such as pressing force, and may warp or bend due to the effects of temperature and humidity.

[0023] Specifically, the base material 5 is attached to the back surface of the vertical frame 3a of panel 2 in Figure 2. As will be described later, this base material 5 is attached to the mounting member 72 in only one place. Therefore, the base material 5 is mounted in a way that results in relatively low rigidity. Panel 2 may also undergo deformation of approximately the same degree or less as the base material 5.

[0024] As shown in Figure 5, the fastening member 6 is a metal screw that is screwed into the panel 2 in a direction almost perpendicular to its surface. The fastening member 6 has a cylindrical body 6a and a head 6b that has a larger diameter than the body 6a. The tip of the body 6a is pointed. The head 6b is a flange-like protruding portion integrally formed at the rear end of the body 6a, and grooves such as "+" and "-" are formed on its rear surface for operation with a tool.

[0025] In contrast to the above configuration, the panel fixing structure of this embodiment may also include the following configuration.

[0026] (1A) The fastening member 6 has a first threaded portion 11 at its tip that screws into both the base material 5 and the portion of the panel frame 3 on the base material 5 side, and a second threaded portion 12 at its rear end that screws into the portion of the panel frame 3 on the surface material 4 side.

[0027] Here, the tip side of the fastening member 6 is the tip and surrounding portion of the body portion 6a. That is, it is the portion opposite to the head portion 6b.

[0028] The part of panel frame 3 on the side of the base material 5 is the back side of panel frame 3.

[0029] The first threaded portion 11 is a spiral projection formed to the required length at the tip and surrounding area of ​​the body portion 6a. The first threaded portion 11 is, for example, a projection with a substantially triangular cross-section. The first threaded portion 11 is screwed in so as to span both the base material 5 and the panel frame 3 after fastening and fixing the panel 2 to the base material 5.

[0030] The rear end of the fastening member 6 is the portion of the body 6a near the head 6b. That is, it is the portion on the side of the head 6b.

[0031] The portion of the panel frame 3 that faces the surface material 4 is the surface side of the panel frame 3.

[0032] The second threaded portion 12 is a spiral projection of a required length formed separately from the first threaded portion 11 in the vicinity of the head 6b on the body portion 6a. The second threaded portion 12 is formed separately from the first threaded portion 11. The second threaded portion 12 is, for example, a projection with a substantially triangular cross-section. The second threaded portion 12 is screwed into the panel frame 3 only, or screwed across both the face material 4 and the panel frame 3, at least after the panel 2 has been fastened and fixed. The second threaded portion 12 may be formed right up to the head 6b, or it may be formed slightly away from the head 6b.

[0033] The panel frame 3 is the thickest and rigidest component of the panel 2, and serves as the core of the panel 2 when it is attached to the base material 5. The fastening member 6 uses the panel frame 3 as a base to pull the base material 5 towards the front by the first screw portion 11 screwed into the panel frame 3. The fastening member 6 also uses the second screw portion 12 screwed into the panel frame 3 to pull the panel 2 towards the front. Therefore, it is important that both the first screw portion 11 and the second screw portion 12 are screwed into the panel frame 3.

[0034] (1B) As shown in Figure 5, the pitch 22 of the second threaded portion 12 may be smaller than the pitch 21 of the first threaded portion 11 (pitch 22 of the second threaded portion 12 < pitch 21 of the first threaded portion 11).

[0035] Here, the pitch 22 of the second threaded portion 12 is the axial distance between the protrusions at the same position in the circumferential direction of the second threaded portion 12. Within the second threaded portion 12, the pitch 22 of the protrusions is uniform throughout. The pitch 22 of the second threaded portion 12 is set to a size that does not damage the facing material 4 and the panel frame 3 and allows the panel frame 3 to be effectively pulled.

[0036] The pitch 21 of the first threaded portion 11 is the axial distance between the protrusions at the same position in the circumferential direction of the first threaded portion 11. Within the first thread, the pitch 21 of the protrusions is uniform throughout. The pitch 21 of the first threaded portion 11 is set to a size that does not damage the base material 5 and the panel frame 3 and allows the base material 5 to be effectively pulled.

[0037] The pitch 22 of the second threaded portion 12 being smaller than the pitch 21 of the first threaded portion 11 means that, for a given length in the axial direction, the second threaded portion 12 is formed in greater numbers (more densely) than the first threaded portion 11. As a result, the amount of axial twisting of the member per turn by the second threaded portion 12 is relatively reduced. Alternatively, the amount of tension on the member twisted in the axial direction per turn by the second threaded portion 12 is relatively reduced.

[0038] Conversely, the pitch 21 of the first threaded portion 11 is larger than the pitch 22 of the second threaded portion 12, and for a given length in the axial direction, the first threaded portion 11 has fewer threads (coarser threads) than the second threaded portion 12. As a result, the amount of axial twisting of the member per turn by the first threaded portion 11 is relatively larger. Alternatively, the amount of tension on the member twisted in the axial direction per turn by the first threaded portion 11 is relatively larger.

[0039] In this case, the pitch 22 of the second threaded portion 12 only needs to be slightly smaller than the pitch 21 of the first threaded portion 11, but it is advantageous to have a somewhat larger difference. However, a difference that is too large is not practical. For example, it is preferable to set the pitch 22 of the second threaded portion 12 within a range that is less than the pitch 21 of the first threaded portion 11, but at least half the pitch 21 of the first threaded portion 11. In particular, it is preferable to set the pitch 22 of the second threaded portion 12 to a value of approximately 2 / 3 ± α of the pitch 21 of the first threaded portion 11. Furthermore, it is preferable that the pitch 22 of the second threaded portion 12 and the pitch 21 of the first threaded portion 11 be made to be easily machined and formed. In this embodiment, the first threaded portion 11 has a normal pitch 21, which is almost the same as a general screw 73 used to fix building panels 2 as shown in Figure 6, while the second threaded portion 12 has a pitch 22 that is smaller than normal. A typical screw 73 has a threaded portion with a uniform pitch 21 that extends continuously for almost the entire length of the body 6a.

[0040] (2) As shown in Figure 4, when the rear end of the fastening member 6 is screwed in to the surface of the facing material 4, The threading range 32 of the second threaded portion 12 with respect to the panel frame 3 may be longer than the threading range 31 of the first threaded portion 11 with respect to the panel frame 3 (threading range 32 of the second threaded portion 12 > threading range 31 of the first threaded portion 11).

[0041] Here, the rear end of the fastening member 6 is the position of the head 6b of the fastening member 6.

[0042] The position of the surface of the facing material 4 is the exposed surface (or design surface) that faces the front of the facing material 4 when viewed from panel 2.

[0043] When the rear end of the fastening member 6 is screwed in to the surface of the panel 4, it means that the head 6b of the fastening member 6 is screwed in flush with the surface of the panel 4. At this time, the panel 2 is assumed to be properly fixed to the base material 5.

[0044] The threading range 32 of the second threaded portion 12 is the axial length of the portion on the surface material 4 side to which the second threaded portion 12 is screwed into the panel frame 3, and is the distance from the back surface of the surface material 4 or the front surface of the panel frame 3. A longer threading range 32 of the second threaded portion 12 is expected to have the effect of eliminating the gap 74. Preferably, the threading range 32 of the second threaded portion 12 is approximately half the thickness of the panel frame 3, or more.

[0045] The threading range 31 of the first threaded portion 11 is the axial length of the portion on the base material 5 side to which the first threaded portion 11 is screwed into the panel frame 3, and is the distance from the surface of the base material 5 or the back surface of the panel frame 3. The threading range 31 of the first threaded portion 11 should be at least approximately one pitch of the first threaded portion 11. Specifically, the threading range 31 of the first threaded portion 11 is set within a range of approximately 0.5 pitch to 2.0 pitch.

[0046] The above describes the configuration of the fastening member 6 used in the embodiment. The fastening member 6 must have a first configuration in which the fastening member 6 of (1A) above is separately provided with a first threaded portion 11 and a second threaded portion 12, each of which is slightly screwed into the panel frame 3, and a second configuration in which the pitch 22 of the second threaded portion 12 of (1B) above is smaller than the pitch 21 of the first threaded portion 11. It is most preferable that the fastening member 6 also has a third configuration in addition to (1A) and (1B) above, in which the screwing range 32 of the second threaded portion 12 of (2) above is longer than the screwing range 31 of the first threaded portion 11. However, even if the fastening member 6 is only a combination of the first and second configurations, a certain degree of effect can be expected.

[0047] (3) As shown in Figure 5(a), the fastening member 6 may have a second threaded portion 12 that extends to the position of the first threaded portion 11.

[0048] Here, it is preferable to make the second threaded portion 12 as long as possible, while ensuring that it is at least the minimum length required for the first threaded portion 11. Here, the second threaded portion 12 is formed to a length that almost reaches the first threaded portion 11. The second threaded portion 12 may be slightly separated from the first threaded portion 11.

[0049] Figure 5(a) shows a configuration that incorporates all of the first, second, and third configurations described above.

[0050] (4) As shown in Figures 5(b) to (d), the fastening member 6 may have a straight portion 41 between the first threaded portion 11 and the second threaded portion 12.

[0051] Here, the straight portion 41 is the cylindrical part of the body 6a of the fastening member 6 that lacks the first threaded portion 11 and the second threaded portion 12. The straight portion 41 has a diameter dimension intermediate between the diameter of the top and the diameter of the base of the protrusions of the first threaded portion 11 and the second threaded portion 12.

[0052] The straight portion 41 is formed in the remaining part after ensuring that the first threaded portion 11 and the second threaded portion 12 have at least the minimum required length. It is preferable that the straight portion 41 be formed so as to be located on the back side of the panel frame 3, rather than around the approximate center in the thickness direction. It is preferable that the straight portion 41 be as short as possible.

[0053] Figures 5(b) to 5(d) show a configuration that incorporates all of the first, second, and third configurations described above. In Figures 5(b) to 5(d), the straight section 41 gets progressively longer.

[0054] (5) As shown in Figures 1 and 2, panel 2 may be any of the wall panel 2a (Figure 2), ceiling panel 2b (Figure 1), or floor panel 2c (Figure 1) for prefabricated housing. As shown in Figures 2 and 3, the base material 5 may also be a connecting portion 51 that extends in the planar direction from the back surface of one of two adjacent panels 2 to the back surface of the other.

[0055] Here, a prefabricated house is a house that can be easily constructed by transporting building materials that have been manufactured or pre-processed in a factory beforehand to the construction site and assembling them there, thereby eliminating major processing work at the construction site.

[0056] Prefabricated housing includes, for example, modular buildings as shown in Figure 1, in which building units 1, manufactured in advance at a factory, are transported to the construction site and constructed by arranging them side by side or stacking them vertically.

[0057] The wall panel 2a is an interior panel 2 that is installed vertically inside a prefabricated house, for example, to form an interior wall.

[0058] The floor panel 2c is an interior panel 2 that, for example, is installed horizontally inside a prefabricated house to form a floor surface.

[0059] The ceiling panel 2b is an interior panel 2 that, for example, is installed horizontally inside a prefabricated house to form a ceiling surface.

[0060] The surface direction is the direction in which the surface of the facing material 4 of the interior panel 2 expands, and in particular, the direction in which the interior panels 2 are installed side by side (adjacent direction).

[0061] The connecting portion 51 is the part that connects adjacent panels 2 to each other. The connecting portion 51 may be formed directly on one of the panels 2, or it may be made of a separate part and attached to the other panel 2. In Figure 3, the connecting portion 51 is a piece of wood that is pre-attached and fixed to the back surface of one side (left side) of the vertical frame 3a of one (right side) panel 2. The connecting portion 51 has an overhanging portion 51a that abuts against and overlaps with the back surface of the other side (right side) of the adjacent vertical frame 3a of the other (left side) panel 2. One panel 2 is installed in the prefabricated house first, and the other panel 2 is installed in the prefabricated house afterward so as to abut against the overhanging portion 51a of the connecting portion 51. After being connected, the other panel 2 becomes one of the panels 2 and similarly connects the next other panel 2.

[0062] Then, with the back surface of the other panel 2 in contact with the connecting portion 51, the fastening member 6 is screwed in perpendicularly to the other panel 2 from the front surface, thereby directly fastening and fixing the other panel 2 to the protruding portion 51a. In this way, one panel 2 and the other panel 2 are connected to each other in an adjacent state without the use of auxiliary tools such as gap-filling jigs.

[0063] The connecting section 51 may be multiple pieces of wood partially attached to one panel 2 along the vertical frame 3a, or it may be a continuous piece of wood attached along the vertical frame 3a from almost the top end to the bottom end. In Figure 2, the connecting section 51 is a continuous piece of wood. The connecting section 51 may or may not be fixed to the building. In the figure, the connecting section 51 is fixed to the building at only one location, at the position of the mounting member 72.

[0064] More specifically, as shown in Figure 1, the building unit 1 has a box-frame structure as its skeletal structure. The upper ends of the unit frame and four columns 61 are connected and fixed in a rectangular shape by four ceiling beams 62, and the lower ends of the four columns 61 are connected and fixed in a rectangular shape by four floor beams 63.

[0065] Then, inside the rectangular ceiling beam 62, multiple ceiling joists 64 extending in the short-side direction are attached in parallel with spacing in the long-side direction, and ceiling surface material 65 is attached to the underside of them. This forms the ceiling panel 2b on the unit frame. Alternatively, for example, the ceiling panel 2b may be attached separately to the underside of the ceiling joists 64 or ceiling surface material 65.

[0066] Similarly, inside the rectangular floor beam 63, multiple floor joists 66 extending in the short-side direction are attached in parallel with spacing in the long-side direction, and floor surface material 67 is attached to the upper side thereof. This forms a floor panel 2c on the unit frame. Alternatively, for example, the floor panel 2c may be attached separately on top of the floor joists 66 and floor surface material 67.

[0067] As shown in Figure 2, metal studs 68 and 69, which extend vertically, are installed parallel to the column 61 with spacing in the long direction between the ceiling beam 62 and the floor beam 63, facing the outside. The exterior wall material 71 is attached to the outer surface of these studs 68 and 69.

[0068] The interior wall panels 2a are installed on the inside of the exterior wall material 71 from the interior side after the exterior wall material 71 has been attached to the unit frame and any distortion of the unit frame has been corrected. Multiple interior wall panels 2a are installed side by side between the columns 61 located on both sides of the exterior side.

[0069] In this configuration, the studs 68 and 69 are C-shaped members with openings on their interior-facing sides, and mounting members 72, such as wooden bricks, are inserted and fixed into the openings of the studs 68 and 69. A portion of the mounting member 72 protrudes inward from the opening.

[0070] For example, the mounting member 72 can be attached to a stud 68 (corner stud) adjacent to a column 61 at multiple locations (for example, four locations) with spacing in the vertical direction. For an intermediate stud 69 located away from the column 61, the mounting member 72 can be attached to only one location approximately in the center in the vertical direction.

[0071] In this way, by reducing the number of mounting members 72 attached to the intermediate studs 69, the building unit 1 can reduce the effort and cost of attaching the mounting members 72 to the intermediate studs 69. Furthermore, as a result, the building unit 1 can reduce the effort of attaching the wall panels 2a to the mounting members 72. Therefore, the productivity of the building unit 1 is significantly improved.

[0072] The first wall panel 2a to be installed is attached to multiple mounting members 72 (the parts of which protrude inward) on the intermediate stud 68 adjacent to the column 61, using standard screws 73, with one vertical edge directly attached from the interior side. The other vertical edge is attached to a connecting part 51 attached to its back surface, using standard screws 73, with one mounting member 72 (the part of which protrudes inward) on the intermediate stud 69, with the other vertical edge directly attached from the interior side.

[0073] In this case, the intermediate studs 68 and 69 are made of metal and therefore possess the required rigidity on their own. Furthermore, their upper and lower ends are fixed between the ceiling beam 62 and floor beam 63 of the unit frame. As a result, when the wall panel 2a is installed, the first wall panel 2a is supported with almost no deformation. Therefore, there is no risk of a gap 74 (Figure 6), as described later, forming between the mounting member 72 and the first wall panel 2a.

[0074] The adjacent wall panel 2a is attached to the connecting portion 51, which is attached to the back surface of the other vertical edge of the first installed wall panel 2a, using the connecting portion 51 as a base material 5, and is directly attached to the connecting portion 51 from the interior side with a fastening member 6.

[0075] Thereafter, similarly, wall panels 2a are successively placed adjacent to each other horizontally until they reach the position of the column 61 on the opposite side, and are connected by fastening members 6 directly to the connecting portion 51 of the previously installed wall panel 2a.

[0076] The last wall panel 2a is directly connected to the connecting portion 51 of the adjacent wall panel 2a using fastening members 6, in the same manner as described above. Then, the remaining vertical edges are fixed in multiple places to the mounting members 72 of the intermediate studs 68 (corner studs) installed adjacent to the column 61, in the same manner as the first wall panel 2a.

[0077] As described above, the wall panels 2a are installed side by side so as to cover the entire side of one side of the building unit 1. Although not specifically explained, each wall panel 2a is fixed at its top and bottom edges to the ceiling and floor portions of the building unit 1, respectively.

[0078] The above panel fixing structure may be applied not only to wall panels 2a, but also to ceiling panels 2b and floor panels 2c.

[0079] Furthermore, when connecting the intermediate wall panels 2a together, the connecting portion 51 is fixed in contact with the mounting member 72 of the stud 69 at only one point, and most of the other parts are not supported on the back side (the connecting portion 51 is away from the stud 69). As a result, the connecting portion 51 is installed in a state of low rigidity.

[0080] Therefore, for example, if one were to attach the wall panel 2a to the connecting part 51 from the indoor side using ordinary screws 73, the connecting part 51 would be deformed, resulting in a gap 74 between the connecting part 51 and the wall panel 2a, as shown in Figure 6.

[0081] <Function>The function of this embodiment will be described below.

[0082] For example, if panel 2 is an interior wall panel 2a, first the exterior wall material 71 is attached to the main body of the building (for example, the unit frame of building unit 1). Then, after the exterior wall material 71 is attached, the distortion of the unit frame is adjusted. In this state, the presence of the exterior wall material 71 prevents the wall panel 2a from being attached from the outside.

[0083] Therefore, in existing designs, as shown in Figure 7, the panel 2 was divided into a panel frame 3 and a facing material 4, and attached to the main body of the building. That is, only the panel frame 3 was placed on the main body of the building from the interior side, and the panel frames 3 were connected to each other in the planar direction using general screws 73. Then, the facing material 4 was attached to the panel frame 3 attached to the main body of the building from the interior side in the planar direction using general screws 73.

[0084] However, if the panel frame 3 and the facing material 4 are attached to the main body of the building separately, the installation of the panel frame 3 and the facing material 4 will be required twice, resulting in more time and effort for installation, as well as a decrease in the precision of the panel 2 itself. In addition, adjusting the surface level difference to make the surfaces of adjacent facing materials 4 flush is time-consuming.

[0085] Therefore, it is preferable to manufacture a panel 2 in which the panel frame 3 and the facing material 4 are pre-integrated, so that the completed panel 2 can be attached to the main body of the building in one go by working from the inside. This offers the advantages of being able to manufacture a high-precision panel 2 by machine and saving time and effort, as it only requires attaching the panel 2 to the main body of the building.

[0086] Therefore, it is being considered to provide a connecting portion 51 that extends laterally on the back surface of one panel 2, using the connecting portion 51 as a base material 5, and to fasten and fix the other panel 2 to the connecting portion 51 from the interior side with a fastening member 6. Furthermore, it is being considered to connect the panels 2 to each other laterally one after another via the connecting portion 51.

[0087] In this case, the connecting section 51 will be made of a material that has the minimum rigidity required for a structural material, such as plywood, from the standpoint of cost and ease of handling. However, a connecting section 51 made of plywood is not as rigid as metal, and it may bend slightly due to external forces such as pressing force, and warp or bend due to the effects of temperature and humidity.

[0088] Therefore, for example, a gap 74 (initial gap) may occur from the beginning between the connecting part 51 and the panel 2 due to warping, bending, or poor contact. Also, during the fastening process with the fastening member 6, the base material 5 may bend due to pressure from the tip of the screw 73, causing a gap to open between it and the panel 2. In such cases, the panel 2 may separate from the connecting part 51 after fastening and fixing, creating a gap 74 (Figure 6). This results in a step difference in the joint between the panels 2, degrading the quality of the inner wall surface. Moreover, since the condition of the back side of the panel 2 cannot be visually inspected, it is difficult to check the situation and take appropriate action.

[0089] In particular, if a general screw 73 is used for the fastening member 6, the amount of tension on the connecting portion 51 by the tip of the screw 73 is equal to the amount of tension on the panel 2 by the rear end of the screw 73. Therefore, if there is an initial gap or deformation due to pressing force in the connecting portion 51, it will not be possible to fill the final gap 74. Furthermore, adjusting the surface step difference between adjacent panels 2 will also be difficult.

[0090] Therefore, while directly fastening and securing panel 2 from the interior side with a standard screw 73 may seem easy at first glance, in reality, the reliability of the results is insufficient, and it has not been feasible in modular buildings where a high level of quality precision is required.

[0091] Therefore, in this embodiment, a special fastening member 6 is used, which has a first threaded portion 11 on its tip side that is screwed across the gap between the base material 5 and the panel frame 3, and a second threaded portion 12 on its rear end side that is screwed into the panel frame 3. In this fastening member 6, the pitch 22 of the second threaded portion 12 is smaller than the pitch 21 of the first threaded portion 11.

[0092] When this special fastening member 6 is used, the first threaded portion 11 at the tip of the fastening member 6 is initially screwed into the panel 2, and then exits the panel 2 and abuts against the connecting portion 51. As a result, the tip of the fastening member 6 pushes against the connecting portion 51, deforming the connecting portion 51 and creating a gap between the panel 2 and the connecting portion 51 (forming a gap 74).

[0093] As long as the connecting portion 51 can move backward, the first threaded portion 11 is hardly screwed into the connecting portion 51. When the connecting portion 51 reaches the limit of deformation due to the pressing force of the fastening member 6, the connecting portion 51 can no longer move backward, and the first threaded portion 11 begins to be screwed into the connecting portion 51. Then, the fastening member 6 continues to be screwed into the connecting portion 51 at a constant speed while maintaining the gap 74 described above, until the second threaded portion 12 begins to be screwed into the panel 2.

[0094] As the second threaded portion 12 begins to be screwed into the panel 2, the fastening member 6 slowly pulls the panel 2 at the rear end due to the second threaded portion 12 with a narrow pitch of 22, while at the front end, the first threaded portion 11 maintains a relatively faster pulling of the connecting portion 51 due to the first threaded portion 11 with a wider pitch of 21. Due to this difference in pulling speed between the second threaded portion 12 and the first threaded portion 11, the gap 74 between the panel 2 and the connecting portion 51 gradually decreases.

[0095] Then, when the rear end (head 6b) of the fastening member 6 is screwed in until it reaches the surface of the panel 4, the gap 74 between the panel 2 and the connecting part 51 is eliminated, and the panel 2 and the connecting part 51 are fixed in a tight fit. Even if there is an initial gap or deformation due to pressing force in the connecting part 51, the final gap 74 can be eliminated. As a result, the other panel 2 is connected flush with the other panel 2 via the connecting part 51.

[0096] In this case, the screwing range 32 of the second screw portion 12 with respect to the panel frame 3 was made longer than the screwing range 31 of the first screw portion 11 with respect to the panel frame 3. This allows the second screw portion 12 to slowly pull the panel 2 for a longer period of time. Therefore, a longer screwing range 32 for the second screw portion 12 is advantageous for eliminating the gap 74 between the panel 2 and the connecting portion 51 by the first screw portion 11.

[0097] <Effects>According to this embodiment, the following effects can be obtained.

[0098] (Effect 1) In the panel fixing structure, the fastening member 6 has a first threaded portion 11 at its tip that screws into both the base material 5 and the portion of the panel frame 3 on the base material 5 side, and a second threaded portion 12 at its rear end that screws into the portion of the panel frame 3 on the surface material 4 side, and the pitch 22 of the second threaded portion 12 may be smaller than the pitch 21 of the first threaded portion 11.

[0099] In this way, by providing the fastening member 6 with a second threaded portion 12 and a first threaded portion 11, and by making the pitch 22 of the second threaded portion 12 and the pitch 21 of the first threaded portion 11 different, the fastening member 6 can change the pulling speed of the panel 2 by the second threaded portion 12 and the pulling speed of the base material 5 by the first threaded portion 11.

[0100] In other words, by making the pitch 22 of the second threaded portion 12 smaller than the pitch 21 of the first threaded portion 11, the fastening member 6 can slowly pull the panel 2 at the rear end of the fastening member 6 by the second threaded portion 12 with a narrower pitch 22 (pulling delay function).

[0101] Conversely, by making the pitch 21 of the first threaded portion 11 wider than the pitch 22 of the second threaded portion 12, the fastening member 6 can quickly pull the base material 5 at the tip side of the fastening member 6 by the first threaded portion 11 with a wider pitch 21 (pulling acceleration function).

[0102] Therefore, the fastening member 6 slowly pulls the panel 2 with the second screw portion 12 while quickly pulling the base material 5 with the first screw portion 11, thereby reducing or eliminating the gap 74 between the base material 5 and the panel 2 compared to when using a typical screw 73.

[0103] In this case, the first threaded portion 11 at the tip of the fastening member 6 is screwed into both the base material 5 and the panel frame 3. Therefore, the first threaded portion 11 functions to pull the base material 5 towards the panel frame 3, using the panel frame 3 as a base, and maintains a gap-free state between the panel frame 3 and the base material 5. Thus, having a first threaded portion 11 that is screwed into both the base material 5 and the panel frame 3 is advantageous for fastening and fixing the panel frame 3 and the base material 5 without any gaps 74.

[0104] Furthermore, since the second threaded portion 12 at the rear end of the fastening member 6 is screwed into the panel frame 3, after fastening is complete, slightly tightening or loosening the fastening member 6 causes the second threaded portion 12 to be displaced axially relative to the panel frame 3, thereby adjusting the position of the panel 2 in the planar direction. Moreover, because the pitch 22 of the second threaded portion 12 at the rear end of the fastening member 6 is narrow, fine adjustment of the position of the panel 2 in the planar direction is possible.

[0105] (Effect 2) In the panel fixing structure, the fastening member 6 may have a screw-in range 32 of the second screw portion 12 with respect to the panel frame 3 that is longer than the screw-in range 31 of the first screw portion 11 with respect to the panel frame 3. This allows the second screw portion 12 to slowly pull the panel 2 over a longer period of time. Meanwhile, the first screw portion 11 can quickly and reliably pull the base material 5.

[0106] Furthermore, the fastening member 6 may have a shorter threaded portion 11 thread engagement range 31 with respect to the panel frame 3 than the threaded portion 2 thread engagement range 32 with respect to the panel frame 3. This allows the second threaded portion 12 to be made longer, while maintaining the function of the first threaded portion 11 to pull and fasten the base material 5, thereby enabling the panel 2 to be pulled slowly over a longer period of time.

[0107] Therefore, for example, even if a gap 74 (initial gap) is created between the base material 5 and the panel 2 from the beginning due to the bending or warping of the base material 5, or if the base material 5 deforms during the fastening work by the fastening member 6, causing a gap 74 to be created between it and the panel 2, it becomes possible to fix the panel 2 directly to the base material 5 (which is in a state of lower rigidity) without any gap 74 by simply screwing the fastening member 6 in from the surface side of the panel 2.

[0108] Furthermore, the panel fixing structure is simple in design and requires minimal effort, as it does not require the use of jigs or other tools to eliminate gaps, and the fastening members 6 can be fastened directly from the surface side of panel 2. In addition, since only the marks left by the fastening members 6 are left on the surface of panel 2, the finished quality is also improved.

[0109] Furthermore, even if there is a certain initial gap between the panel frame 3 and the base material 5, the panel frame 3 and the base material 5 can be installed without any gaps 74. Since the initial gap cannot be visually confirmed from the surface side of the panel 2, it is important that the panel frame 3 and the base material 5 can be installed without any gaps 74 even if there is an initial gap.

[0110] (Effect 3) In the panel fixing structure, the fastening member 6 may have a second screw portion 12 that extends to the position of the first screw portion 11. This allows the fastening member 6 to maintain the effect of slowly pulling the panel 2 with the second screw portion 12 for the longest possible time, thereby maximizing its function of attaching the panel frame 3 and the base material 5 without any gaps 74. Furthermore, even if there is a larger initial gap between the panel frame 3 and the base material 5, the panel frame 3 and the base material 5 can be attached without any problems without any gaps 74.

[0111] (Effect 4) In the panel fixing structure, the fastening member 6 may have a straight portion 41 between the first threaded portion 11 and the second threaded portion 12. By separating the first threaded portion 11 and the second threaded portion 12 with the straight portion 41, the fastening member 6 can clearly separate the portion in which the first threaded portion 11 promotes the attraction of the base material 5 and the portion in which the second threaded portion 12 delays the attraction of the panel 2, thereby simplifying the structure of the fastening member 6.

[0112] Furthermore, by providing the straight portion 41, it becomes unnecessary to form the first threaded portion 11 and the second threaded portion 12 to connect over the entire length of the fastening member 6, thus making it easier to manufacture the fastening member 6 and reducing its manufacturing cost.

[0113] Furthermore, by providing the straight section 41, the fastening member 6 can be screwed in with less force. Therefore, work efficiency can be improved.

[0114] (Effect 5) In the panel fixing structure, the panel 2 may be any of the wall panel 2a, floor panel 2c, or ceiling panel 2b for prefabricated housing. The base material 5 may also be a connecting portion 51 that extends in the planar direction from the back surface of one of two adjacent panels 2 to the back surface of the other. By arranging prefabricated housing panels 2 such as wall panels 2a, floor panels 2c, and ceiling panels 2b adjacent to each other and fastening them to the connecting portion 51 from the surface side with a fastening member 6, even if the connecting portion 51 warps or bends, for example, the gap 74 between the connecting portion 51 and the panel 2 can be eliminated, and adjacent panels 2 can be connected and fixed flush. [Examples]

[0115] The following describes specific examples.

[0116] For example, as shown in Figure 4, panel 2 has a total thickness of 42.5 mm, of which the facing material 4 has a thickness T1 of 12.5 mm, and the panel frame 3 has a thickness T2 of 30 mm. The base material 5 has a thickness T3 of 5.5 mm.

[0117] Overall thickness of panel 2: 42.5 mm Thickness of the facing material 4 of panel 2: 12.5mm (T1) Panel frame 3 thickness: 30.0mm (T2) Thickness of base material 5: 5.5mm (T3)

[0118] In contrast, a fastening member 6 with a total length of 65 mm is used. The fastening member 6 is 17 mm longer than the total thickness of the entire panel 2 and the base material 5, and after fastening and fixing, the tip protrudes a maximum of 17 mm from the back side of the base material 5. However, the dimensions of each component such as the panel 2, base material 5, and fastening member 6 are not limited to those stated above.

[0119] First, we prepared Examples 1 to 4 as shown in Figures 5(a) to 5(d).

[0120] The fastening member 6 of Embodiment 1 shown in Figure 5(a) has a second threaded portion 12 with a length of 40 mm, a pitch 22 of the second threaded portion 12 of 2.0 mm, a first threaded portion 11 with a length of 25 mm, a pitch 21 of the first threaded portion 11 of 2.8 mm, and a straight portion 41 with a length of 0 mm.

[0121] In the fastening member 6 of Embodiment 2 shown in Figure 5(b), the length of the second threaded portion 12 is 35 mm, the pitch 22 of the second threaded portion 12 is 2.0 mm, the length of the first threaded portion 11 is 25 mm, the pitch 21 of the first threaded portion 11 is 2.8 mm, and the length of the straight portion 41 is 5 mm.

[0122] In the fastening member 6 of Embodiment 3 shown in Figure 5(c), the length of the second threaded portion 12 is 30 mm, the pitch 22 of the second threaded portion 12 is 2.0 mm, the length of the first threaded portion 11 is 25 mm, the pitch 21 of the first threaded portion 11 is 2.8 mm, and the length of the straight portion 41 is 10 mm.

[0123] The fastening member 6 of Embodiment 4 shown in Figure 5(d) has a second threaded portion 12 with a length of 25 mm, a pitch 22 of the second threaded portion 12 of 2.0 mm, a first threaded portion 11 with a length of 25 mm, a pitch 21 of the first threaded portion 11 of 2.8 mm, and a straight portion 41 with a length of 15 mm.

[0124] Second thread section (pitch) First thread section (pitch) Straight section (unit: mm) Example 1 40(2.0) 25(2.8) 0 Example 2 35(2.0) 25(2.8) 5 Example 3 30(2.0) 25(2.8) 10 Example 4 25(2.0) 25(2.8) 15

[0125] In this case, all of the embodiments 1 to 4 include a first configuration in which the fastening member 6 described above is separately provided with a first threaded portion 11 and a second threaded portion 12, each of which is slightly screwed into the panel frame 3; a second configuration in which the pitch 22 of the second threaded portion 12 is smaller than the pitch 21 of the first threaded portion 11; and a third configuration in which the threading range 32 of the second threaded portion 12 is longer than the threading range 31 of the first threaded portion 11.

[0126] Furthermore, these differ in the length of the second threaded portion 12 and the length of the straight portion 41. The length of the second threaded portion 12 increases in the order of Example 1 to Example 4, while the length of the straight portion 41 decreases in the order of Example 1 to Example 4.

[0127] The pitch 22 of the second threaded portion 12 and the length and pitch 21 of the first threaded portion 11 are all the same. The pitch 22 of the second threaded portion 12 is 5 / 7 the size of the pitch 21 of the first threaded portion 11.

[0128] Therefore, In Example 1, the threading range 32 of the second threaded portion 12 is 27.5 mm, and the threading range 31 of the first threaded portion 11 is 2.5 mm. In Example 2, the threading range 32 of the second threaded portion 12 is 22.5 mm, and the threading range 31 of the first threaded portion 11 is 2.5 mm. In Example 3, the threading range 32 of the second threaded portion 12 is 17.5 mm, and the threading range 31 of the first threaded portion 11 is 2.5 mm. In Example 4, the threading range 32 of the second threaded portion 12 is 12.5 mm, and the threading range 31 of the first threaded portion 11 is 2.5 mm.

[0129] In other words, the threading range 32 of the second threaded portion 12 increases in the order of Example 1 to Example 4, while the threading range 31 of the first threaded portion 11 is the same in all cases.

[0130] Threading range (second thread section) Threading range (first thread section) Example 1 27.5 2.5 Example 2 22.5 2.5 Example 3 17.5 2.5 Example 4 12.5 2.5 (Above, in mm)

[0131] Then, using the fastening members 6 of Examples 1 to 4, the panel 2 was fastened and fixed to the base material 5 (connecting part 51) from the surface side. During this process, the initial gap between the panel 2 and the base material 5 was set to 1 mm, 3 mm, 5 mm, 7 mm, and 10 mm for the experiment.

[0132] As a result, it was confirmed that in all cases, the fastening members 6 of Examples 1 to 3 could fasten and fix the panel 2 to the base material 5 (connecting part 51) from the surface side without any gaps 74.

[0133] Furthermore, it was confirmed that the fastening member 6 of Example 4 can fasten and fix the panel 2 to the base material 5 (connecting part 51) from the surface side without any gaps 74, as long as the initial gap is up to 3 mm.

[0134] Therefore, it was confirmed that Examples 1 to 3 are practically usable with no margin for error, and Example 4 is fully practical.

[0135] Furthermore, since the performance improved in the order of Examples 1 to 4, it was confirmed that the longer the threading range 32 of the second threaded portion 12, the more effective it is. In Example 4, the initial gap was 5 mm and the final gap 74 was large, so it is considered preferable to make the threading range 32 of the second threaded portion 12 larger than 5 times the threading range 31 of the first threaded portion 11.

[0136] Initial gap 1mm 3mm 5mm 7mm 10mm Evaluation Example 1 ○ ○ ○ ○ ○ OK Example 2 ○ ○ ○ ○ ○ OK 3 (excluding all others) ○ ○ ○ ○ ○ OK Example 4 ○ ○ Remaining 6mm △

[0137] Furthermore, in order to verify the effects of the first to third configurations, we prepared Example 5 as shown in Figure 8 and Comparative Examples 1 to 3 as shown in Figures 9(a) to (c), and conducted the same experiment as described above.

[0138] In the fastening member 6A of Example 5 shown in Figure 8, the length of the second threaded portion 12 is 15 mm, the pitch 22 of the second threaded portion 12 is 2.0 mm, the length of the first threaded portion 11 is 25 mm, the pitch 21 of the first threaded portion 11 is 2.8 mm, and the length of the straight portion 41 is 25 mm. In other words, in Example 5, the second threaded portion 12 is shorter compared to Examples 1 to 4.

[0139] The fastening member 6B of Comparative Example 1 shown in Figure 9(a) has a second threaded portion 12 with a length of 15 mm, a pitch 22a of the second threaded portion 12 of 2.8 mm, a first threaded portion 11 with a length of 25 mm, a pitch 21 of the first threaded portion 11 of 2.8 mm, and a straight portion 41 with a length of 25 mm. Comparative Example 1 differs from Example 5 in that the pitch 22a of the second threaded portion 12 is different.

[0140] In Comparative Example 2, shown in Figure 9(b), the fastening member 6C has a second threaded portion 12 with a length of 30 mm, a pitch 22 of the second threaded portion 12 of 2.0 mm, a first threaded portion 11 with a length of 22.5 mm, a pitch 21 of the first threaded portion 11 of 2.8 mm, and a straight portion 41 with a length of 12.5 mm. In Comparative Example 2, the first threaded portion 11 is shorter compared to Example 3 in Figure 5(c).

[0141] The fastening member 6D of Comparative Example 3, shown in Figure 9(c), has a second threaded portion 12 with a length of 30 mm, a pitch 22 of the second threaded portion 12 of 2.0 mm, a first threaded portion 11 with a length of 20 mm, a pitch 21 of the first threaded portion 11 of 2.8 mm, and a straight portion 41 with a length of 15 mm. Compared to Comparative Example 2, Comparative Example 3 has an even shorter first threaded portion 11. In addition, the second threaded portion 12 is a reverse thread.

[0142] Second thread section (pitch) First thread section (pitch) Straight section (unit: mm) Example 5 15(2.0) 25 (2.8) 25 Comparative Example 1 15(2.8) 25 (2.8) 25 Comparative Example 2: 30 (2.0) 22.5 (2.8) 12.5 Comparative Example 3: 30 (2.0) 20 (2.8) 15

[0143] In Example 5, the threading range 32 of the second threaded portion 12 is 2.5 mm, and the threading range 31 of the first threaded portion 11 is 2.5 mm. In Comparative Example 1, the threading range 32 of the second threaded portion 12 is 2.5 mm, and the threading range 31 of the first threaded portion 11 is 2.5 mm. In comparative example 2, the threading range 32 of the second threaded portion 12 is 17.5 mm, and the threading range 31 of the first threaded portion 11 is 0 mm. In comparative example 3, the threading range 32 of the second threaded portion 12 is 17.5 mm, and the threading range 31 of the first threaded portion 11 is 0 mm.

[0144] Threading range (second thread section) Threading range (first thread section) Example 5 2.5 2.5 Comparative Example 1 2.5 2.5 Comparative Example 2 17.5 0 Comparative Example 3: 17.5 0 (or greater, in mm)

[0145] First, in Example 5 and Comparative Example 1, the threading range 32 of the second threaded portion 12 is reduced to be the same as the threading range 31 of the first threaded portion 11. Also, in Comparative Example 1, the pitch 22b of the second threaded portion 12 is the same as the pitch 21 of the first threaded portion 11.

[0146] In this case, Embodiment 5 has a first configuration in which the fastening member 6 described above is separately provided with a first threaded portion 11 and a second threaded portion 12, each of which is slightly screwed into the panel frame 3, and a second configuration in which the pitch 22 of the second threaded portion 12 is smaller than the pitch 21 of the first threaded portion 11, but it does not have a third configuration in which the screwing range 32 of the second threaded portion 12 is longer than the screwing range 31 of the first threaded portion 11. The effect of the third configuration will be tested in this Embodiment 5.

[0147] Comparative Example 1 comprises only the first configuration described above, and lacks the second and third configurations. In Comparative Example 1, the effects of the second configuration are also tested.

[0148] Furthermore, in Comparative Examples 2 and 3, although the pitch 22 of the second threaded portion 12 and the pitch 21 of the first threaded portion 11 are made different, and the second threaded portion 12 is made longer, in both cases the first threaded portion 11 does not have a screwing range 31 with respect to the panel frame 3.

[0149] Comparative Examples 2 and 3 have only the second configuration described above, and do not have the first or third configurations. In Comparative Example 1, the effect of the first configuration is tested. The threading range 32 of the second threaded portion 12 is the same as in Example 3. The first threaded portion 11 of Comparative Example 3 is a reverse thread, and the effect of the reverse thread is also tested.

[0150] Then, using the fastening members 6A to 6D of Example 5 and Comparative Examples 1 to 3, the panel 2 was directly fastened and fixed to the base material 5 (connecting portion 51) from the surface side, as shown in Figures 3 and 4. In this case, as described above, the experiment was conducted with the initial gap between the panel 2 and the base material 5 set to 1 mm, 3 mm, 5 mm, 7 mm, and 10 mm.

[0151] The results were as follows: In Example 5, where the second threaded portion 12 was short, there was no gap 74 when the initial gap was 1 mm, the gap 74 was 2 mm when the initial gap was 3 mm, and the gap 74 was 11 mm when the initial gap was 5 mm.

[0152] In comparative example 1, where the second threaded portion 12 is short and the pitch 22 of the second threaded portion 12 is wide, there was no gap 74 when the initial gap was 1 mm, the gap 74 was 11 mm when the initial gap was 3 mm, and the gap 74 was 13 mm when the initial gap was 5 mm.

[0153] In comparative example 2, where the first threaded portion 11 is shorter, the gap 74 was 2 mm when the initial gap was 1 mm, 11 mm when the initial gap was 3 mm, and 11 mm when the initial gap was 5 mm.

[0154] In comparative example 3, where the first threaded portion 11 is short and has a reverse thread, the gap 74 was 5 mm when the initial gap was 1 mm, 13 mm when the initial gap was 3 mm, and 13 mm when the initial gap was 5 mm.

[0155] Initial gap 1mm 3mm 5mm Evaluation Example 5 ○ Remaining 2mm Remaining 11mm △ Comparative example 1 ○ 11mm remaining 13mm remaining NG Comparative example 2 2mm remaining 11mm remaining 11mm NG Comparative example 3 5mm remaining 13mm remaining 13mm NG

[0156] Based on the above, the performance was best in Example 5, followed by Comparative Examples 1 to 3. Furthermore, the fastening member 6A in Example 5 and the fastening members 6B to 6D in Comparative Examples 1 to 3 all performed better than the general screw 73, which produces a gap 74 even without an initial gap.

[0157] Example 5 was evaluated as barely usable, as it could be used if the initial gap was less than 3 mm.

[0158] Comparative Example 1 was evaluated as having some practical difficulties because the gap 74 became too large when the initial gap was 3 mm, making it difficult to use.

[0159] Comparative Examples 2 and 3 were evaluated as being difficult to commercialize because even with an initial gap of 1 mm, a certain amount of gap 74 was formed, and when the initial gap was 3 mm, the gap 74 became too large, making it difficult to use.

[0160] Furthermore, since it was predicted that the fastening and fixing situation would not improve with initial gaps of 5 mm, 7 mm, and 10 mm, no experiments were conducted in those cases.

[0161] Furthermore, in Example 5 and Comparative Example 1, it was confirmed that when the initial gap was 1 mm, the panel 2 could be fastened and fixed to the base material 5 (connecting part 51) from the surface side without any gaps 74. When the initial gap was 3 mm, a gap 74 occurred in both cases, but the gap 74 was smaller in Example 5 than in Comparative Example 1.

[0162] Therefore, in comparison with Examples 1 to 4, it was confirmed that under the same conditions, a longer second threaded portion 12 is more effective in eliminating the gap 74, thus demonstrating the effectiveness of the third configuration (making the threaded range 32 larger than the threaded range 31). Furthermore, in comparison with Comparative Example 1, it was confirmed that the second configuration, in which the pitch 22 of the second threaded portion 12 is smaller than the pitch 21 of the first threaded portion 11, is effective.

[0163] Furthermore, in comparison with Example 3, it was confirmed that the first configuration is effective because eliminating the threading range 31 of the first threaded portion 11, as in Comparative Examples 2 and 3, does not provide sufficient tension on the base material 5 (connecting portion 51). In addition, Comparative Example 3 confirmed that no particular effect is obtained even when using a reverse thread.

[0164] In summary, the results showed that simply separating the first threaded portion 11 and the second threaded portion 12 provided a slight improvement compared to a typical screw 73, but the effect was still insufficient. It was confirmed that the first threaded portion 11, by ensuring a small threading range 31 with respect to the panel frame 3, enables sufficient tightening of the base material 5 (connecting portion 51). Furthermore, it was confirmed that differentiating the pitch 21 of the first threaded portion 11 and the pitch 22 of the second threaded portion 12 allows for faster and more effective tightening of the base material 5 (connecting portion 51). Finally, it was confirmed that lengthening the threading range 32 of the second threaded portion 12 allows for a longer time to tighten the base material 5 (connecting portion 51). [Explanation of symbols]

[0165] 1. Building Unit (Prefabricated House) 2 panels 2a Wall panel 2c floor panel 2b Ceiling panel 3 Panel Frame 4-sided material 5. Substrate 6 Fastening members 11 First threaded section 12 Second threaded section 22 pitch 21 pitch 31 Threading range 32 Threading range 41 Straight section 51 Connecting part

Claims

1. A panel fixing structure is provided in which a panel, which has a facing material attached to the surface of a panel frame, is fastened and fixed from the surface side of the panel to a wooden base material installed on the back side of the panel, which is thinner than the facing material of the panel and has the same or lower rigidity as the panel, using fastening members. The fastening member, in its fastened and fixed state, has a first threaded portion at its tip that protrudes from the base material and screws into both the base material and the portion of the panel frame on the base material side, and a second threaded portion at its rear end that screws into the portion of the panel frame on the surface material side. A panel fixing structure characterized in that the pitch of the second screw portion is smaller than the pitch of the first screw portion, and the first screw portion is screwed into the panel frame by a pitch of 0.5 to 2.

0.

2. A panel fixing structure according to claim 1, When the rear end of the fastening member is screwed in to the surface of the facing material, A panel fixing structure characterized in that the screwing range of the second screw portion with respect to the panel frame is longer than the screwing range of the first screw portion with respect to the panel frame.

3. A panel fixing structure according to claim 1 or claim 2, The fastening member is characterized in that the second threaded portion extends to the position of the first threaded portion.

4. A panel fixing structure according to claim 1 or claim 2, The panel fixing structure is characterized in that the fastening member has a straight portion between the first threaded portion and the second threaded portion.

5. A panel fixing structure according to claim 1 or claim 2, The aforementioned panel is one of the wall panels, ceiling panels, or floor panels for prefabricated housing. The panel fixing structure is characterized in that the base material is a connecting portion that extends in the planar direction from the back surface of one of the two adjacent panels toward the back surface of the other panel.

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