Ceiling panels and how to remove them

Abstract

To provide a ceiling panel and a panel removal method that can reduce the joint width between the ceiling panels and efficiently perform a construction of the ceiling panel and partial panel replacement.SOLUTION: While a first fixing part 21 of a ceiling panel 1 is provided with a first protruding piece 22 with a back side facing proximity to a part of a second fixing part 41 of the adjacent panel, and a first recess 23 for exposing a part of the second fixing part 41 of the adjacent panel, the second fixing part 41 of the ceiling panel 1 is provided with a second protruding piece 42 with a part of the surface facing proximity to the first protruding piece 22 of the adjacent panel and exposing a part of the surface by the first recess 23 of the adjacent panel, and a second recess 43 which is blocked by the first protruding piece 22 of the adjacent panel.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a ceiling panel in which a first edge portion and a second edge portion located on both sides of a panel body in one direction are fixed to a ceiling substrate. [Background technology]

[0002] A conventional proposal, as shown in the conventional diagram (Figure 9) of Patent Document 1, involves overlapping the fixing portions (flanges) provided on the peripheral edges of the panel body between adjacent ceiling panels and fixing them to the ceiling substrate with fasteners. Because of this fixing structure in which the flanges are overlapped, the width of the joints between the panel bodies can be made small enough to be inconspicuous. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 5-272192 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the method described in the above document, when replacing a ceiling panel sandwiched between adjacent ceiling panels, not only the ceiling panel to be replaced but also the adjacent ceiling panels must be removed, which makes the construction work less efficient.

[0005] The present invention has been proposed in consideration of the above circumstances, and its purpose is to provide a ceiling panel and a panel removal method that can reduce the joint width between ceiling panels and enable efficient installation of ceiling panels and partial panel replacement. [Means for solving the problem]

[0006] In order to achieve the above object, the ceiling panel of the present invention has a flat panel body having a rectangular outer shape in a plan view, and a first edge portion and a second edge portion located on both sides of one direction of the panel body are fixed to a ceiling substrate, and the first edge portion of the panel body is provided with a first fixing portion that is fixed to the ceiling substrate by a fixing device along the longitudinal direction of the first edge portion, while the second edge portion of the panel body is provided with a first fixing portion that is fixed to the ceiling substrate by a fixing device along the longitudinal direction of the second edge portion. The first fixing portion has a first protrusion whose back surface faces and is close to a part of the second fixing portion of the adjacent ceiling panel, and a first recess that exposes a part of the second fixing portion of the adjacent ceiling panel, while the second fixing portion has a second protrusion whose front surface faces and is close to the first protrusion of the adjacent ceiling panel and whose front surface can be exposed by the first recess of the adjacent ceiling panel, and a second recess that is blocked by the first protrusion of the adjacent ceiling panel.

[0007] Furthermore, the panel removal method of the present invention is a panel removal method for removing one ceiling panel from between the ceiling panel on the first edge side and the ceiling panel on the second edge side when multiple ceiling panels are attached to the ceiling substructure, and is characterized in that the fasteners of the first fixing portion of the ceiling panel adjacent to the second edge side of the ceiling panel to be removed are loosened, the fasteners of the second fixing portion of the ceiling panel to be removed are removed, the fasteners of the first fixing portion of the ceiling panel to be removed are removed, the first edge of the ceiling panel to be removed is moved downward to tilt the ceiling panel, and the ceiling panel is slid diagonally downward.

[0008] Another panel removal method of the present invention is a panel removal method for removing one ceiling panel from between the ceiling panel on the first edge side and the ceiling panel on the second edge side when multiple ceiling panels are attached to the ceiling substructure, characterized in that the fasteners of the second fixing portion of the ceiling panel to be removed are removed, the fasteners of the first fixing portion of the ceiling panel to be removed are removed, the first edge portion of the ceiling panel to be removed is moved downward to tilt the ceiling panel, and the ceiling panel is slid diagonally downward.

[0009] Furthermore, still another panel removal method of the present invention is a panel removal method for removing one ceiling panel from between the ceiling panel on the first edge side and the ceiling panel on the second edge side when multiple ceiling panels are attached to the ceiling substructure, characterized in that the fasteners of the first fixing portion of the ceiling panel adjacent to the second edge side of the ceiling panel to be removed are loosened, the fasteners of the second fixing portion of the ceiling panel to be removed are loosened, the fasteners of the first fixing portion of the ceiling panel to be removed are removed, the first edge of the ceiling panel to be removed is moved downward to tilt the ceiling panel, and the ceiling panel is slid diagonally downward.

[0010] Furthermore, still another panel removal method of the present invention is a panel removal method for removing one ceiling panel from between the ceiling panel on the first edge side and the ceiling panel on the second edge side when multiple ceiling panels are attached to the ceiling substructure, characterized in that the fasteners of the second fixing portion of the ceiling panel to be removed are loosened, the fasteners of the first fixing portion of the ceiling panel to be removed are removed, the first edge portion of the ceiling panel to be removed is moved downward to tilt the ceiling panel, and the ceiling panel is slid diagonally downward. [Effects of the Invention]

[0011] Since the ceiling panel of the present invention has the above-described configuration, the joint width between the ceiling panels can be reduced, and the installation of the ceiling panels and partial panel replacement can be carried out efficiently.

[0012] Furthermore, since the panel removal method of the present invention follows the procedure described above, removal of the ceiling panel for partial replacement can be carried out efficiently. [Brief explanation of the drawings]

[0013] [Figure 1] 1A and 1B are a schematic bottom view and enlarged partial bottom view of two positions of a ceiling panel in a separated state showing the manner in which the panels engage with each other according to one embodiment of the present invention. [Figure 2] 1A and 1B are a schematic bottom view and enlarged partial bottom view of two positions of the ceiling panel showing the engagement state between the panels of the ceiling panel. [Figure 3] 2 is a schematic plan view of the ceiling panel in a separated state showing the manner in which the panels are engaged with each other, and an enlarged partial plan view of two locations. [Figure 4] 3 is an enlarged vertical cross-sectional view taken along line AA in FIG. 1 (line BB in FIG. 3). [Figure 5] 10(a) and 10(b) are schematic bottom views showing the procedure for installing the ceiling panel. [Figure 6] This is a diagram to explain the procedure for removing the same ceiling panel, where (a) is a schematic bottom view of the ceiling panel to be removed, (b) is an enlarged view of part C in (a), and (c) is an enlarged view of part D in (a). [Figure 7] 10(a) to 10(c) are schematic vertical cross-sectional views showing the procedure for removing the ceiling panel. [Figure 8] 4 is an enlarged vertical cross-sectional view of a ceiling panel according to another embodiment of the present invention, corresponding to the line BB in FIG. 3. [Figure 9] 10(a) to 10(c) are schematic vertical cross-sectional views showing the procedure for removing the ceiling panel. [Figure 10] 10A and 10B are a schematic bottom view and an enlarged partial bottom view of a separated state showing the manner in which panels of ceiling panels according to yet another embodiment of the present invention are engaged with each other. [Figure 11] 10(a) to 10(c) are schematic vertical cross-sectional views showing the procedure for removing the ceiling panel. [Figure 12]4 is an enlarged vertical cross-sectional view of a ceiling panel according to still another embodiment of the present invention, corresponding to the line BB in FIG. 3. [Figure 13] 10(a) to 10(c) are schematic vertical cross-sectional views showing the procedure for removing the ceiling panel. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. First, the basic configuration of the ceiling panel 1 according to this embodiment will be described.

[0015] This ceiling panel 1 has a flat panel body 10 with a rectangular outer shape when viewed from above, and a first edge portion 10a and a second edge portion 10b located on both sides of one direction of the panel body 10 are fixed to a ceiling substructure 70.

[0016] A first fixing portion 21 is provided on the first peripheral edge 10a of the panel body 10 along the longitudinal direction (side direction) of the first peripheral edge 10a, and is fixed to the ceiling substrate 70 by a fixing device 60. Meanwhile, a second fixing portion 41 is provided on the second peripheral edge 10b of the panel body 10, and is fixed to the ceiling substrate 70 by a fixing device 60, and is also provided on the second peripheral edge 10b along the longitudinal direction (side direction) of the second peripheral edge 10b.

[0017] The first fixing portion 21 comprises a first protrusion 22 whose back surface faces and is close to a part of the second fixing portion 41 of the adjacent ceiling panel 1, and a first recess 23 that exposes a part of the second fixing portion 41 of the adjacent ceiling panel 1. The second fixing portion 41 comprises a second protrusion 42 whose front surface faces and is close to the first protrusion 22 of the adjacent ceiling panel 1 and whose front surface can be exposed by the first recess 23 of the adjacent ceiling panel 1, and the second recess 43 that is blocked by the first protrusion 22 of the adjacent ceiling panel 1. Note that, here, facing and close to each other means that surfaces face each other in a close proximity, and also includes facing surfaces abutting each other.

[0018] Next, the details of the present ceiling panel 1 will be described with reference to Figures 1 to 4. In the description of this embodiment, the up-down direction is defined based on the installed state of the ceiling panel 1. In other words, the surface exposed to the indoor space below the ceiling panel 1 is the lower surface (bottom surface), and the back surface facing the ceiling substrate 70 is the upper surface (flat surface).

[0019] Fig. 1 is a schematic bottom view of the separated state showing the inter-panel engagement on the surface (underside) of the ceiling panel 1, and an enlarged partial bottom view at two locations. Fig. 2 is a schematic bottom view of the same engaged state and an enlarged partial bottom view at two locations. Fig. 3 is a schematic plan view of the same separated state and an enlarged partial plan view at two locations. Fig. 4 is an enlarged vertical cross-sectional view corresponding to line AA in Fig. 1 (line BB in Fig. 3).

[0020] The ceiling panel 1 comprises a rectangular panel body 10, a first fixing piece 20 attached to a first edge portion 10a of the long side thereof, a second fixing piece 40 attached to a second edge portion 10b of the other long side, and a reinforcing piece 65 attached to each of the edge portions of the short sides.

[0021] The first fixing piece 20, the second fixing piece 40, and the reinforcing piece 65 are all made of, for example, metal material and are long and extend along the edge, and act as reinforcing members that suppress sagging and distortion of the edge portion of the panel main body 10 after installation. The first fixing piece 20 and the second fixing piece 40 are each held and fixed by holding pieces (first holding piece 30, second holding piece 50) provided on the panel main body 10 side, as will be described in detail in Figure 4.

[0022] The retaining pieces are members that, together with the fixing pieces, maintain the strength of the ceiling panel 1, and may be made of, for example, a metal material, but are provided with slotted portions 38, 58 such as elongated holes in order to reduce the overall weight of the ceiling panel 1 (see the enlarged view in Figure 3). Details of the first and second retaining pieces 30, 50 will be described later together with an explanation of the vertical cross-sectional view shown in Figure 4.

[0023] The first edge portion 10a and the second edge portion 10b, which are both edge portions in one direction of the ceiling panel 1, are arranged at corresponding positions on the ceiling substrate 70. In this embodiment, the ceiling substrate 70 is made up of a plurality of elongated rafters 70 arranged at equal intervals and parallel to one another. In other words, the first edge portion 10a and the second edge portion 10b of the ceiling panel 1 are each fixed to the corresponding rafters 70 along their longitudinal directions.

[0024] The rafters 70 are formed in the shape of channel steel as shown in Figure 4, and the ceiling panel 1 is attached to the underside of the rafters 70 so as to span between the rafters 70. In other words, the short side dimension of the ceiling panel 1 corresponds to the dimension between the rafters 70, but the short side of the ceiling panel 1 may correspond to three or more rafters 70.

[0025] The ceiling panel 1 may be fixed so that the first edge portion 10a and the second edge portion 10b are aligned perpendicular to the longitudinal direction of the joist 70. The ceiling panel 1 may be attached to a ceiling substrate such as a T-bar instead of the joist 70.

[0026] Two adjacent ceiling panels 1 along the arrangement direction of the joists 70 are fixed to the underside of the joists 70 with fasteners 60 so that the protruding portions of the first and second fixing pieces 20, 40 that protrude outward from the panel body 10 overlap with parts of the second and first fixing pieces 40, 20 of the adjacent panels. This protruding portion is the first fixing portion 21 in the first fixing piece 20, and the second fixing portion 41 in the second fixing piece 40. The fasteners 60 may be screws such as point screws or nails.

[0027] The first fixing portion 21 has a plurality of discontinuous first protrusions 22 along the longitudinal direction of the first peripheral portion 10a, with first recesses 23 formed between the first protrusions 22. The second fixing portion 41 has a plurality of discontinuous second protrusions 42 along the longitudinal direction of the second peripheral portion 10b, with second recesses 43 formed between the second protrusions 42. As shown in FIG. 1, the shapes of the protrusions of the first fixing portion 21 and the second fixing portion 41 are different from each other, and multiple types of protrusions are provided in each fixing portion.

[0028] The first protrusions 22 include two first protrusions (ends) 221 located at both ends of the first peripheral portion 10a in the longitudinal direction, with shorter first protrusions (short) 222 and longer first protrusions (long) 223 arranged alternately in the middle between them. The length of the first protrusions (ends) 221 is approximately half the length of the first protrusions (long) 223. In the illustrated example, the middle between the first protrusions (ends) 221 is arranged, in order from the end of the first peripheral portion 10a, with the first protrusions (short) 222, first protrusions (long) 223, first protrusions (short) 222, first protrusions (long) 223, and first protrusions (short) 222.

[0029] First elongated holes 22a extending in a direction perpendicular to the longitudinal direction of the first edge portion 10a are formed in one location on the first protruding piece (end) 221, one location on the first protruding piece (short) 222, and two locations on the first protruding piece (long) 223. Note that, as shown in Fig. 1 etc., the first elongated holes 22a may be notches extending from the end edge of the first protruding piece 22 toward the panel main body 10.

[0030] The first recesses 23 are formed between the first protruding pieces 22, and the lengths of the first recesses 23 along the longitudinal direction of the first edge portion 10a are approximately the same. The first recesses 23 are formed as approximately isosceles trapezoidal openings between the first protruding pieces 22, with the portion cut out from the edge of the first fixing portion 21 (first protruding piece 22) to the edge (edge) of the panel main body 10.

[0031] On the other hand, the second fixing portion 41 has two second protrusions (ends) 421 located on both ends of the second peripheral portion 10b and a plurality of second protrusions (long) 422 arranged in the middle between them, with second recesses 43 formed between the second protrusions 42. The second protrusions (long) 422 are approximately twice as long as the second protrusions (ends) 441 and are approximately the same length as each other. In the illustrated example, eight second protrusions (long) 422 are arranged in the middle between the two second protrusions (ends) 421.

[0032] The second protrusions (long) 422 include those with second elongated holes 42a formed that extend along the longitudinal direction of the second peripheral portion 10b, and those without any openings such as elongated holes. No elongated holes are formed in the second protrusions (end) 421. In the illustrated example, the second protrusions (long) 422 are arranged in the following order from the end side of the second peripheral portion 10b: with elongated hole, with elongated hole, without elongated hole, with elongated hole, with elongated hole, without elongated hole, with elongated hole, with elongated hole.

[0033] The second recesses 43 are formed between the second protruding pieces 42, and the lengths of the second recesses 43 along the longitudinal direction of the second edge portion 10b are approximately the same. The second recesses 43 are formed as approximately isosceles trapezoidal openings between the second protruding pieces 42, with the portion cut out from the edge of the second fixing portion 41 (second protruding piece 42) to the edge (edge) of the panel main body 10.

[0034] With these two types of first fixing portion 21 and second fixing portion 41, the formation location of first elongated hole 22a of first protrusion 22 corresponds to second recess 43 of the adjacent panel, and the formation location of second elongated hole 42a of second protrusion 42 corresponds to first recess 23 of the adjacent panel. Also, a part of the part where first elongated hole 22a of first protrusion 22 is not formed corresponds to a part of the part where second elongated hole 42a of second protrusion 42 is not formed. In other words, between two adjacent ceiling panels 1 after installation, second fixing portion 41 and first fixing portion 21 are arranged in an up-down relationship, but there is a non-overlapping portion between them due to the formation of the recess, i.e., the placement of fasteners.

[0035] The first fixing portion 21 and the second fixing portion 41 are engaged with each other so as to overlap, and are fixed to the siding 70. More specifically, the first fixing portion 21 is disposed below the second fixing portion 41 so as to overlap the surface (lower surface) of the second fixing portion 41. As a result, as shown in FIGS. 1 to 3 , the second protruding piece 42 and the first protruding piece 22 partially overlap each other vertically, and the portion where the first elongated hole 22a is provided overlaps the second recess 43, and the portion where the second elongated hole 42a is provided overlaps the first recess 23.

[0036] In other words, there is no component of the second fixing piece 40 above the first elongated hole 22a, and there is no component of the first fixing piece 20 below the second elongated hole 42a. In other words, the first fixing portion 21 and the second fixing portion 41 overlap between two adjacent ceiling panels 1, but the fastener 60 is fixed to the joist 70 via the fixing portion of one of the panels.

[0037] The diagram shown in Figure 4 is an enlarged vertical cross-sectional view taken along line BB in Figure 3 (corresponding to line AA in Figure 1), and as shown in Figure 4, at the position of line BB, the second protrusion 42 and the first protrusion 22 are closely overlapped vertically.

[0038] Next, the detailed configuration of the first fixing piece 20 and the second fixing piece 40 and the manner in which the first fixing piece 20 and the second fixing piece 40 are fixed to the panel body 10 will be described with reference to the enlarged vertical cross-sectional view of FIG.

[0039] The panel body 10 comprises a substrate 11, a surface layer 12 provided on the surface side of the substrate 11, and a back layer 13 provided on the back side of the substrate. The substrate 11 is made of, for example, a foamed resin or fiber material, as shown in FIG.

[0040] The first fixing piece 20 is held and fixed by a first holding piece 30 provided on the panel main body 10. This first holding piece 30 includes a first base portion 31 fixed to the back surface of the panel main body 10, and a first fitting piece portion 32 formed so as to extend further toward the edge than the first base portion 31 and curve and bulge out. The first base portion 31 is fixed to the panel main body 10 by a connecting member 34.

[0041] The first fixing piece 20 comprises a first fixing portion 21, a first base portion 25 extending inward (towards the panel main body 10) from the first fixing portion 21 in a flat plate shape, and a first inclined piece portion 26 extending from the first base portion 25 in a downward inclined shape towards the back surface of the panel main body 10. The first fixing piece 20 further comprises a first upright piece portion 24 extending from the boundary between the first fixing portion 21 and the first base portion 25 towards the back surface of the panel main body 10 in a direction perpendicular to the first base portion 25. Two rib strips 25a are formed on the upper surface of the first base portion 25.

[0042] A space is formed surrounded by the first upright piece 24, the first base 25, and the first inclined piece 26, and this space serves as the first mating recess 27 into which the first mating piece 32 of the first retaining piece 30 fits.

[0043] With the first fitting recess 27 of the first fixing piece 20 fitted into the first fitting piece 32 of the first holding piece 30, the lower end of the first upright piece 24 abuts against the rear surface of the panel main body 10, and the inner surface of the first inclined piece 26 closely overlaps the outer surface of the flat portion of the first fitting piece 32. In this state, the first inclined piece 26 and the flat portion of the first fitting piece 32 are fixed together with the fixing device 36, and the first fixing piece 20 is fixed to the panel main body 10 so that the first fixing portion and the first base 25 are parallel to the panel main body 10. The second fixed piece 40 is fixed in the same manner as the first fixed piece 20.

[0044] The second fixing piece 40 is held and fixed by a second holding piece 50 provided on the panel main body 10. This second holding piece 50 includes a second base portion 51 fixed to the back surface of the panel main body 10, and a second fitting piece portion 52 formed so as to extend further toward the edge than the second base portion 51 and curve and bulge out. The second base portion 51 is fixed to the panel main body 10 by a connecting member 54.

[0045] The second fixing piece 40 includes a second fixing portion 41, a second base portion 45 extending inward (toward the panel main body 10) in a flat plate shape from the base end of the second fixing portion 41 via a step (at the lower step portion), and a second inclined piece portion 46 extending in a downward inclined shape from the second base portion 45 toward the back surface of the panel main body 10. The second fixing piece 40 further includes a second upright piece portion 44 extending from the boundary between the second fixing portion 41 and the second base portion 45 toward the back surface of the panel main body 10 in a direction perpendicular to the second base portion 45. A single rib 45a is formed on the upper surface of the second base portion 45.

[0046] A space is formed surrounded by the second upright piece 44, the second base 45, and the second inclined piece 46, and this space serves as a second mating recess 47 into which the second mating piece 52 of the second holding piece 50 fits.

[0047] With the second fitting recess 47 of the second fixing piece 40 fitted into the second fitting piece 52 of the second holding piece 50, the lower end of the second upright piece 44 abuts against the rear surface of the panel main body 10, and the inner surface of the second inclined piece 46 closely overlaps the outer surface of the flat portion of the second fitting piece 52. In this state, the second inclined piece 46 and the flat portion of the second fitting piece 52 are fixed together with the fixing device 56, and the second fixing piece 40 is fixed to the panel main body 10 so that the second fixing portion 41 and the second base 45 are parallel to the panel main body 10.

[0048] As described above, the ceiling panel 1 has a fixed structure in which the first fixing portion 21 is disposed between adjacent ceiling panels 1 so as to overlap the underside of the second fixing portion 41 of the adjacent ceiling panel 1. Therefore, the first and second fixing pieces 20, 40 are formed such that the second fixing portion 41 is positioned higher than the first fixing portion 21 by a step, as described in FIG.

[0049] The siding 70 to which the ceiling panel 1 is attached comprises a base plate portion 71 and side plate portions 74 rising from both widthwise ends of the base plate portion 71. The base plate portion 71 has two reinforcing ribs 73 in the longitudinal direction, with a plate-shaped central base portion 72 between them. The second and first fixing portions 41, 21 of two adjacent ceiling panels 1, which overlap each other above and below, are fixed to this central base portion 72 with fasteners 60.

[0050] As explained in Figures 1 to 4, the ceiling panel 1 is attached to the joist 70 so that its fixing portion overlaps the fixing portion of the adjacent ceiling panel 1. Therefore, the joint width between the ceiling panels 1 (panel bodies 10) corresponds to the width dimension of one fixing portion, so the joint width dimension does not become too large, and it is possible to avoid the aesthetic appearance being impaired by the joints.

[0051] In this embodiment, the first fixing portion 21 has a first recess 23, and the second fixing portion 41 has a second recess 43. However, by overlapping the two fixing portions, a protrusion exists above or below the recess. Therefore, the surface (underside) of the siding 70 is not exposed due to the recess, and the siding 70 is covered by one or two protrusions. Therefore, it is possible to prevent the surface color of the siding 70, such as the metallic color, from blending with the surface color of the fixing portion and being exposed to the outside.

[0052] Furthermore, the fixing pieces (first fixing piece 20, second fixing piece 40) have a vertical cross section with a stepped shape (protruding toward the back side) as shown in Fig. 4, and are arranged in a position recessed behind the back surface of panel main body 10, so the boundary between first fixing portion 21 and second fixing portion 41 and fastener 60 are not easily noticeable individually. Note that the decorative surface may be a dark color such as black to make the surfaces (undersides) of first fixing portion 21 and second fixing portion 41 less noticeable.

[0053] Furthermore, each ceiling panel 1 is arranged so that the first fixing portion 21 supports the second fixing portion 41 of the adjacent panel from below, and the second fixing portion 41 is supported from below by the first fixing portion 21 of the other adjacent panel. Therefore, the dependency between adjacent ceiling panels 1 is approximately the same for all ceiling panels 1, which prevents only some ceiling panels 1 from being prone to downward displacement.

[0054] Moreover, the first fixing portion 21 and the second fixing portion 41 are each individually fixed to the joist 70 with fasteners 60, so that each ceiling panel 1 is securely attached to the joist 70. In other words, between the ceiling panels 1, not only the first fixing portion 21 located on the lower side but also the second fixing portion 41 are fixed to the joist 70 with fasteners 60, so that the ceiling panel 1 can be installed firmly.

[0055] In addition, in this embodiment, multiple pairs of first protrusions 22 and first recesses 23 are provided alternately on the first edge portion 10a, and multiple pairs of second protrusions 42 and second recesses 43 are provided on the second edge portion 10b, thereby enabling the ceiling panel 1 to be securely and firmly attached to the sill 70.

[0056] Furthermore, in this embodiment, the second recess 43 is formed at the location where the first protrusion 22 is fixed to the siding 70 by the fastener 60, and the first recess 23 is formed at the location where the second protrusion 42 is fixed to the siding 70 by the fastener 60, so the fixing pieces do not overlap at the fixing location. Therefore, at both fixing portions, it is not necessary to provide one insertion hole for the fastener 60 at each side corresponding to the same position in the longitudinal direction of the edge portion, and therefore efficient construction can be carried out without the need for position (hole) alignment.

[0057] In other words, the second recess 43 in the second fixing portion 41 acts as a clearance hole for fixing the first protrusion 22 of the first fixing portion 21 of the adjacent panel with the fastener 60. On the other hand, the first recess 23 of the first fixing portion 21 acts as a recess for avoiding contact with the head of the fastener 60 attached to the second protrusion 42 of the second fixing portion 41 of the adjacent panel. Note that in this embodiment, the first recess 23 and the second recess 43 are both notched recesses, but the first recess 23 may be a hole large enough to avoid contact with the head of the fastener 60, and the second recess 43 may be a hole large enough to allow the fastener 60 to pass through.

[0058] In this way, the first fixing portion 21 and the second fixing portion 41 of the adjacent panel have a mixture of overlapping and non-overlapping portions, and the balance between these depends on the number of portions to be fastened with the fastener 60. Increasing the number of fastening portions using the fastener 60 increases the individual fastening strength of each ceiling panel 1, but the overlapping area becomes smaller, so the degree of dependency on adjacent panels decreases. Conversely, reducing the number of fastening portions using the fastener 60 decreases the individual fastening strength of each ceiling panel 1, but the overlapping area becomes larger, so the degree of dependency on adjacent panels increases.

[0059] For example, in the example of this embodiment, the second elongated hole 42a may be formed in the second protruding piece (long) 422 (see FIG. 1) where the second elongated hole 42a is not formed, and a new first recess 23 may be provided in the middle of the first protruding piece (long) 223 at a position corresponding to the second elongated hole 42a. In this way, the number of fastening locations using the fastener 60 increases, but the overlapping area between the first fixing portion 21 and the second fixing portion 41 of the adjacent panel decreases, reducing the degree of dependency on each other.

[0060] As described above, the first fixing portion 21 and the second fixing portion 41 have not only protrusions but also recesses, which provides various effects such as more efficient installation by fastening with the fasteners 60. In particular, providing the first recess 23 and the second recess 43, which are cutout-shaped and sufficiently larger than the screw insertion holes, also contributes to reducing the weight of the ceiling panel 1.

[0061] 5(a) and 5(b) are schematic bottom views showing the procedure for installing the ceiling panels 1. Adjacent ceiling panels 1 are installed so that the second fixing portions 41 abut against the base portion 71 of the joist 70, and the first fixing portions 21 abut against the second fixing portions 41, and the fasteners 60 are attached to the first and second protruding pieces 22, 42 in positions where the protruding pieces do not overlap. In this way, the ceiling panels 1 can be installed one by one in order. In the example of FIGS. 1 to 3, the ceiling panels 1 can be installed in the order left, then right.

[0062] First, the first fixing portion 21 of the ceiling panel 1 to be attached is placed on the underside of the second fixing portion 41 of the previously fixed ceiling panel 1, and the fastener 60 is passed through the first long hole 22a of the first protrusion 22 to temporarily fix it (see part X1 in Figure 5(a)).

[0063] Next, the second fixing portion 41 of the ceiling panel 1 to be attached is aligned with the second elongated hole 42a of the second protrusion 42 to the base portion 71 of the joist 70, and the second fixing portion 41 is permanently fixed to the joist 70 with the fastener 60 (see portion X2 in FIG. 5(b)). In this case, since the first fixing portion 21 is a temporary fixation, the ceiling panel 1 can be fine-tuned in the arrangement direction of the joist 70 before the second fixing portion 41 is permanently fixed to the joist 70.

[0064] Figure 5(b) shows a state in which, due to fine adjustment, the first fixing portion 21 is slightly misaligned with the second fixing portion 41 of the already fixed ceiling panel 1, and once the position is determined, the fastener 60 is permanently fixed in that state (see part X3 in Figure 5(b)). In this way, the first fixing portion 21 is fixed even if it is slightly misaligned with the second fixing portion 41 of the adjacent ceiling panel 1, but the first protrusion 22 is in a state in which it partially overlaps the second protrusion 42 of the adjacent ceiling panel 1 (see Figure 5(b)). In this way, the multiple ceiling panels 1 are attached to the joist 70 one by one in sequence.

[0065] Next, a method for removing a ceiling panel 1 sandwiched between adjacent ceiling panels 1 for purposes such as partial replacement of the ceiling panel 1 will be described with reference to Figures 6 and 7. Figure 6(a) is a schematic bottom view including the ceiling panel 1 to be removed, (b) is an enlarged view of part C in (a), and (c) is an enlarged view of part D in (a). Figures 7(a) to (c) are schematic vertical cross-sectional views showing the procedure for removing the ceiling panel 1.

[0066] First, loosen the fasteners 60 attached to the first elongated holes 22a of all the first protrusions 22 of the first fixing portion 21 of the ceiling panel 1 adjacent to the second edge portion 10b of the ceiling panel 1 to be removed (see part Y1 in Figures 6(a) and 6(b) and Figure 7(a)). This creates a space S.

[0067] Next, the fasteners 60 attached to the second elongated holes 42a of all of the second projections 42 of the second fixing portions 41 located on the second peripheral portion 10b of the ceiling panel 1 to be removed are removed (see FIGS. 6(a) and 6(c) and part Y2 in FIG. 7(b)). When all of the fasteners 60 for the second projections 42 have been removed in this manner, the second projections 42 of the ceiling panel 1 to be removed come off the joist 70. However, the second projections 42 are positioned in the space S created between the joist 70 and the first projections 22 of the adjacent panel, which is now hanging down due to the loosening of the fasteners 60, and are held from below by the first projections 22 (see FIG. 7(b)).

[0068] Next, the fasteners 60 attached to the first long holes 22a of all the first protrusions 22 of the first fixing portion 21 located on the first edge portion 10a of the ceiling panel 1 to be removed are removed (see part Y3 in Figures 6(a)(b) and Figure 7(b)).

[0069] When all of the fasteners 60 of the first protrusions 22 are removed in this manner, the first fixing portion 21 of the ceiling panel 1 to be removed comes off the joist 70. Because the first fixing portion 21 is disposed below the second fixing portion 41 of the ceiling panel 1 adjacent to the first edge portion 10a, the first edge portion 10a of the ceiling panel 1 to be removed becomes movable downward.

[0070] Then, the first edge portion 10a of the ceiling panel 1 to be removed is moved downward to tilt the ceiling panel 1, and the ceiling panel 1 can be removed by sliding it diagonally downward (see Figure 7(c)).

[0071] The above panel removal method can be summarized as follows: Loosen the fastener 60 of the first fixing portion 21 of the ceiling panel 1 adjacent to the second edge portion 10b of the ceiling panel 1 to be removed. The fasteners 60 of the second fixing portions 41 of the ceiling panel 1 to be removed are removed. The fasteners 60 of the first fixing portions 21 of the ceiling panel 1 to be removed are removed. The first edge portion 10a of the ceiling panel 1 to be removed is moved downward to tilt the ceiling panel 1, and the ceiling panel 1 is then slid obliquely downward.

[0072] In this way, since this ceiling panel 1 has an overlapping engagement structure as described above in relation to adjacent ceiling panels 1, it can be easily removed without having to remove the adjacent ceiling panels 1 on either side.

[0073] More specifically, the second fixing portion 41 and the first fixing portion 21 of adjacent panels partially overlap each other, but the second protrusion 42 and the first protrusion 22 are individually fixed to the joist 70 with fasteners 60. Therefore, when removing one ceiling panel 1, it is sufficient to remove only the fastener 60 of that ceiling panel 1.

[0074] Because the adjacent ceiling panels 1 on either side are individually secured with fasteners 60, removing the ceiling panel 1 to be removed will have little effect on the adjacent ceiling panels 1 on either side. As explained in Figures 6 and 7, it is only necessary to loosen the fasteners 60 for the first fixing portion 21 of the ceiling panel 1 adjacent to the second edge portion 10b, and there is no need to loosen the fasteners 60 for the second fixing portion 41 of the ceiling panel 1 adjacent to the first edge portion 10a.

[0075] To mount a new ceiling panel 1 in the position from which it was removed, the removal procedure described above with reference to FIGS. 6 and 7 can be roughly reversed.

[0076] Specifically, first, the ceiling panel 1 to be attached is tilted, and its second fixing portion 41 is inserted into the space S created between the first fixing portion 21 of the ceiling panel 1 adjacent to the second edge portion 10b side and the sill 70.

[0077] Next, the first fixing portion 21 of the ceiling panel 1 to be attached is fixed to the joist 70 with the fastener 60, and then the second fixing portion 41 is also fixed to the joist 70 with the fastener 60.

[0078] Then, the first fixing portion 21 of the ceiling panel 1 adjacent to the second edge portion 10b of the ceiling panel 1 to be attached, which fastener 60 was loosened when the ceiling panel 1 was removed, is permanently fixed to the joist 70.

[0079] In this way, when replacing the ceiling panel 1, the installation of a new ceiling panel 1 can be carried out easily and efficiently.

[0080] When replacing such a ceiling panel 1, it is desirable to attach the second fixing portion 41 of the new ceiling panel 1 to a different position of the second elongated hole 42a from that of the removed ceiling panel 1, that is, to another position on the joist 70. This makes it possible to avoid attaching the fastener 60 to an existing hole in the joist 70, thereby preventing the ceiling panel 1 from shifting or falling.

[0081] In addition, the first fixing portion 21 may be provided with a mixture of a first elongated hole 22a that allows fine adjustment and a long elongated hole (third elongated hole) (not shown) that is long along the edge, similar to the second elongated hole 42a.

[0082] By doing so, in the first peripheral portion 10a, as with the second fixing portion 41, when replacing the ceiling panel 1 with a new one, it is possible to avoid attaching the fastener 60 to the hole in the existing joist 70. In the case of a ceiling panel provided with such a third elongated hole, the fastener 60 can be attached to the third elongated hole when the fastener 60 is permanently fixed to the first elongated hole 22a (X3 in FIG. 5(b)).

[0083] Furthermore, the first protruding piece 22 may be provided with a plurality of first elongated holes 22a, including a spare first elongated hole 22a, in order to fasten a new replacement ceiling panel 1 with a fastener 60.

[0084] In this way, by providing the first fixing portion 21 with a third elongated hole and a spare first elongated hole 22a, it is possible to avoid attaching the fastener 60 to an already opened hole in the sill 70, as with the second fixing portion 41.

[0085] In this embodiment, the fastener insertion holes provided in the first protrusion 22 and the second protrusion 42 are elongated holes (first elongated hole 22a, second elongated hole 42a) that allow fine adjustments and changes in insertion position, but this is not limited to this and they may also be round holes that do not allow fine adjustments or changes in insertion position.

[0086] 1 to 7, when the ceiling panel 1 is attached, the first protrusion 22 and the second protrusion 42 abut against each other and no gap is formed between the first fixing portion 21 and the second fixing portion 41, but a small gap (clearance) may be formed. For example, the ceiling panel 1 may have a vertical cross section as shown in FIG. 8. The vertical cross section of FIG. 8 corresponds to line BB in FIG. 3.

[0087] The ceiling panel 1 shown in Figure 8 differs from that shown in Figure 4 in terms of the shapes of the first fixing pieces 20 and the second fixing pieces 40, particularly in the vertical cross-sectional shape. Note that, regarding the shape in plan view, specifically the planar positions and numbers of the first protruding pieces 22, first elongated holes 22a, first recesses 23, second protruding pieces 42, second elongated holes 42a, and second recesses 43, are the same as those in Figures 1 to 3, and therefore bottom and plan views are omitted.

[0088] In the example shown in Figure 8, the shape of the first base 25 including the rib strip 25a on the panel body 10 side of the first fixing portion 21 of the first fixing piece 20 differs from that shown in Figure 4. Two protrusions 25b and 25c are formed on the first base 25, and the ceiling panel 1 is attached so that both of these protrusions abut against the underside of the base plate 71 of the joist 70. These protrusions 25b and 25c also function as rib strips.

[0089] When the ceiling panel 1 is installed, these protrusions 25b, 25c abut against the underside of the base portion 71 so as to avoid the recessed lines on the back side created by the reinforcing ribs 73 of the base portion 71 of the joist 70. Since the first fixing portion 21 (first protruding piece 22) is not arranged to abut against the second fixing portion 41 of the adjacent panel, it is desirable to provide two protrusions 25b, 25c as shown in the illustration and install them wider than the width of the joist 70 in order to arrange them in a more stable state. Note that in the illustration, the protrusion 25b on the side of the first inclined piece 26 is formed wider than the protrusion 25c on the side of the first fixing portion 21.

[0090] Alternatively, instead of being separated like protrusions 25b and 25c, an integrated protrusion may be provided, that is, first base 25 may be thick enough to include the thickness of protrusions 25b and 25c. Furthermore, protrusions 25b and 25c may come into contact with the bottom surface of the recessed stripe on the back side of reinforcing rib 73 or may fit into the recessed stripe.

[0091] Furthermore, the first fixing portion 21 is not formed at the same height level as the first base portion 25, but is formed in a stepped shape at a position slightly lower than the first base portion 25 via a protruding portion 25c on the first fixing portion 21 side. In this way, due to the height position of the first fixing portion 21 and the protruding height of the protruding portions 25b and 25c, a gap S1 is formed between the first fixing portion 21 and the second fixing portion 41 of the adjacent ceiling panel 1 (the ceiling panel 1 on the left side in FIG. 8), as shown in FIG.

[0092] On the other hand, the second fixed piece 40 has a protrusion 45b formed on the second inclined piece portion 46 side of the second base portion 45. This protrusion 45b is formed in approximately the same position as the rib strip 45a shown in FIG. 4, but like the second fixed piece 41 (second protrusion 42), it abuts against the underside of the base portion 71 of the joist 70 to attach the ceiling panel 1. In other words, the second fixed piece 40 has the second fixed piece 41 (second protrusion 42) and protrusion 45b abut against the base portion 71 of the joist 70, so that it is stably disposed relative to the joist 70. Furthermore, like the protrusion 25b on the first inclined piece portion 26 side of the first fixed piece 20, the protrusion 45b is wide.

[0093] When two ceiling panels 1 are attached adjacent to the joist 70 in this manner, a gap S1 is formed between the first fixing portion 21 (first protruding piece 22) and the second fixing portion 41 (second protruding piece 42). In other words, the protruding pieces in this case do not abut against each other but face each other in close proximity with the gap S1 (clearance) interposed therebetween. In other words, this ceiling panel 1 has protruding portions 25b, 25c on the panel main body 10 side of the first fixing portion 21 that abut against the ceiling substrate (joist) 70 and maintain the distance between the first fixing portion 21 and the ceiling substrate 70 at a dimension that exceeds the thickness of the second protruding piece 42.

[0094] After this ceiling panel 1 has been installed, if the ceiling panel 1 sandwiched between adjacent ceiling panels 1 needs to be removed for partial replacement or the like, it is removed in the procedure shown in Figures 9(a) to 9(c).

[0095] 9(a) shows the state after the ceiling panel 1 has been installed. Here, the fastener 60 does not need to be removed or loosened for the first fixing portion 21 of the ceiling panel 1 adjacent to the second edge portion 10b side of the ceiling panel 1 to be removed (the central ceiling panel 1 in the figure).

[0096] First, remove the fasteners 60 attached to the second long holes 42a of all the second protrusions 42 of the second fixing portion 41 located on the second edge portion 10b of the ceiling panel 1 to be removed (see portion Y11 in Figure 9(b)).

[0097] When all of the fasteners 60 for the second protrusion 42 are removed in this way, the second protrusion 42 of the ceiling panel 1 to be removed comes off the joist 70. However, the second protrusion 42 remains held between the joist 70 and the first protrusion 22 of the adjacent panel. When all of the fasteners 60 for the second protrusion 42 are removed, the gap S1 formed in the installed state disappears, the first protrusion 22 and the second protrusion 42 come into contact, and instead another gap is formed between the second protrusion 42 and the joist 70.

[0098] Next, the fasteners 60 attached to the first long holes 22a of all the first protrusions 22 of the first fixing portion 21 located on the first edge portion 10a of the ceiling panel 1 to be removed are removed (see part Y12 in Figure 9(b)).

[0099] When all of the fasteners 60 of the first protrusion 22 are removed in this manner, the first fixing portion 21 of the ceiling panel 1 to be removed comes off the joist 70. The first fixing portion 21 is arranged below the second fixing portion 41 of the ceiling panel 1 adjacent to the first edge portion 10a, and the second fixing portion 41 is arranged with a gap between the joist 70 and the first fixing portion 21. Because the ceiling panel 1 to be removed is arranged in this state, the first edge portion 10a can be easily moved downward.

[0100] Then, the first edge portion 10a of the ceiling panel 1 to be removed is moved downward to tilt the ceiling panel 1, and the ceiling panel 1 can be removed by sliding it diagonally downward (see Figure 9(c)).

[0101] The above panel removal method can be summarized as follows: The fasteners 60 of the second fixing portions 41 of the ceiling panel 1 to be removed are removed. The fasteners 60 of the first fixing portions 21 of the ceiling panel 1 to be removed are removed. The first edge portion 10a of the ceiling panel 1 to be removed is moved downward to tilt the ceiling panel 1, and the ceiling panel 1 is then slid obliquely downward.

[0102] Thus, with this ceiling panel 1, when removing the ceiling panel 1 to be removed, there is no need to remove or loosen the fasteners 60 of the first fixing portions 21 of the adjacent ceiling panel 1 on the second edge portion 10b side (see Figures 9(a) and 7(a)). In other words, the gap S1 formed between the second fixing portion 41 and the first fixing portion 21 of the adjacent panel in the installed state acts in the same way as the space S created by removing the fasteners 60 of the adjacent panel in Figure 7, allowing for easier and more efficient removal.

[0103] In this embodiment, similar to the embodiment shown in FIGS. 1 to 7, the second fixing portion 41 (second protruding piece 42) has the second elongated hole 42a formed as the fastener insertion hole. However, the second protruding piece 42 may have a round hole or a notched open hole 42b (see FIG. 10) formed instead of the second elongated hole 42a. In these cases, the ceiling panel 1 can be removed using the same procedure as in FIG. 9. Removal is even easier when the open hole 42b is formed. This will be explained below.

[0104] Fig. 10 is a schematic bottom view and an enlarged partial bottom view showing a separated state of a ceiling panel 1 according to yet another embodiment, in which an open hole 42b is provided in the second peripheral portion 10b, where the edge of the second peripheral portion 10b is opened in a notched shape, instead of the second elongated hole 42a. Fig. 10 also shows an enlarged partial bottom view of the second fixing portion 41 (second protrusion 42) and the first fixing portion 21 of the adjacent panel, in a separated state and an engaged state, respectively. The ceiling panel 1 of this embodiment has the longitudinal cross-sectional shape shown in Fig. 8.

[0105] In the example of Figure 10, the open hole 42b has a shape symmetrical to the first elongated hole 22a (see Figures 2 and 10), but it does not have to be an elongated hole extending in a direction perpendicular to the longitudinal direction of the second edge portion like the first elongated hole 22a, as long as at least the end face is open and the fastener 60 can be inserted through it.

[0106] After this ceiling panel 1 has been installed, if the ceiling panel 1 sandwiched between adjacent ceiling panels 1 needs to be removed for partial replacement or the like, it is removed in the procedure shown in Figures 11(a) to (c).

[0107] 11(a) shows the state after the ceiling panel 1 has been installed. Here, the fastener 60 does not need to be removed or loosened for the first fixing portion 21 of the ceiling panel 1 adjacent to the second edge portion 10b side of the ceiling panel 1 to be removed (the central ceiling panel 1 in the figure).

[0108] First, the fasteners 60 attached to the open holes 42b of all the second projections 42 of the second fixing portions 41 located on the second peripheral portion 10b of the ceiling panel 1 to be removed are loosened (see part Y21 in Figure 11(b)). At this time, the gap S1 formed in the installed state becomes smaller, and the second projections 42 come closer to abutting the first projections 22, and instead another gap is formed between the second projections 42 and the joist 70.

[0109] Next, the fasteners 60 attached to the first long holes 22a of all the first protrusions 22 of the first fixing portion 21 located on the first edge portion 10a of the ceiling panel 1 to be removed are removed (see part Y22 in Figure 11(b)).

[0110] When all of the fasteners 60 of the first protrusion 22 are removed in this manner, the first fixing portion 21 of the ceiling panel 1 to be removed comes off the joist 70. The first fixing portion 21 is disposed below the second fixing portion 41 of the ceiling panel 1 adjacent to the first edge portion 10a, and the second fixing portion 41 is disposed with a gap between the joist 70 and the first fixing portion 21. Because the ceiling panel 1 to be removed is disposed in this state, the first edge portion 10a becomes movable downward.

[0111] Then, the first edge portion 10a of the ceiling panel 1 to be removed is moved downward to tilt the ceiling panel 1, and the ceiling panel 1 can be removed by sliding it diagonally downward (see Figure 11(c)).

[0112] The above panel removal method can be summarized as follows: Loosen the fasteners 60 of the second fixing portions 41 of the ceiling panel 1 to be removed. The fasteners 60 of the first fixing portions 21 of the ceiling panel 1 to be removed are removed. The first edge portion 10a of the ceiling panel 1 to be removed is moved downward to tilt the ceiling panel 1, and the ceiling panel 1 is then slid obliquely downward.

[0113] Thus, with this ceiling panel 1, when removing the ceiling panel 1 to be removed, there is no need to remove or loosen the fasteners of the first fixing portion of the ceiling panel 1 adjacent to the second edge portion 10b (see FIG. 11(a)). Furthermore, it is only necessary to loosen the second fixing portion 41 of the ceiling panel 1 to be removed, which allows for even more efficient removal than the case of FIG. 9.

[0114] 10, it is desirable to make all fastener insertion holes of the second fixing portion 41 open holes 42b in order to facilitate smooth removal, but some of the fastener insertion holes may be second elongated holes 42a (see FIG. 1). In that case, it goes without saying that when removing the ceiling panel 1, the fasteners 60 inserted into the second elongated holes 42a must of course be removed as shown in FIG.

[0115] As described above, Figures 1 to 7 show an engagement mode between adjacent panels in which parts of the second fixing portion 41 and the first fixing portion 21 abut against each other and the fastener insertion hole of the second fixing portion 41 is an elongated hole. Figures 8 and 9 also show an engagement mode in which there is a gap S1 between the second fixing portion 41 and the first fixing portion 21 and the fastener insertion hole of the second fixing portion 41 is an elongated hole. Figures 8, 10, and 11 also show an engagement mode in which there is a gap S1 between the second fixing portion 41 and the first fixing portion 21 and the fastener insertion hole of the second fixing portion 41 is an open hole 42b.

[0116] As another engagement mode, as shown in Fig. 12, portions of the second fixing portion 41 and the first fixing portion 21 may abut against each other, and the fastener insertion hole of the second fixing portion 41 may be an open hole 42b, similar to that shown in Fig. 10. In this embodiment, the ceiling panel 1 in which the second fixing portion 41 and the first fixing portion 21 abut against each other between adjacent panels may be that shown in Fig. 4, but here the description will be given using the one shown in Fig. 12, which has a vertical cross-sectional shape different from that shown in Fig. 4.

[0117] 8, the ceiling panel 1 shown in Fig. 12 has a first fixing piece 20 with two protrusions 25b, 25c, and a second fixing piece 40 with one protrusion 45b. These protrusions 25b, 25c, and 45b all come into contact with the base plate 71 of the joist 70 when adjacent panels are engaged with each other. In this state, the first fixing portion 21 and the second fixing portion 41 come into contact with each other.

[0118] 12, the protruding height of protrusions 25b, 25c of first fixing portion 21 is approximately the same as the thickness of second fixing portion 41 (second protruding piece 42), and the height position of protrusion 45b of second fixing portion 41 is approximately the same as the height position of second fixing portion 41 (second protruding piece 42). In this way, in the installed state of ceiling panel 1, both first fixing piece 20 and second fixing piece 40 are disposed in a more stable state relative to joist 70, similar to that of FIG.

[0119] After this ceiling panel 1 has been installed, if the ceiling panel 1 sandwiched between adjacent ceiling panels 1 needs to be removed for partial replacement or the like, it is removed in the procedure shown in Figures 13(a) to (c).

[0120] First, loosen the fasteners 60 attached to the first elongated holes 22a of all the first protrusions 22 of the first fixing portion 21 of the ceiling panel 1 adjacent to the second edge portion 10b of the ceiling panel 1 to be removed (see portion Y31 in Figure 13(a)). This creates a space S.

[0121] Next, the fasteners 60 attached to the open holes 42b of all of the second protrusions 42 of the second fixing portions 41 located on the second edge portion 10b of the ceiling panel 1 to be removed are loosened. When all of the fasteners 60 of the second protrusions 42 are loosened in this manner, the second fixing portions 41 move downward in the space S and are held from below by the first fixing portions 21 of the adjacent panel that have already been loosened (see part Y32 in Figure 13(b)).

[0122] Then, the fasteners 60 attached to the first long holes 22a of all the first protrusions 22 of the first fixing portion 21 located on the first edge portion 10a of the ceiling panel 1 to be removed are removed (see part Y33 in Figure 13(b)).

[0123] When all of the fasteners 60 of the first protrusion 22 are removed in this manner, the first fixing portion 21 of the ceiling panel 1 to be removed comes off the joist 70. The first fixing portion 21 is disposed below the second fixing portion 41 of the ceiling panel 1 adjacent to the first edge portion 10a, and the second fixing portion 41 is disposed with a space S between the joist 70 and the first fixing portion 21. Because the ceiling panel to be removed is disposed in this state, the first edge portion 10a becomes movable downward.

[0124] Then, the first edge portion 10a of the ceiling panel 1 to be removed is moved downward to tilt the ceiling panel 1, and the ceiling panel 1 can be removed by sliding it diagonally downward (see Figure 13(c)).

[0125] The above panel removal method can be summarized as follows: Loosen the fastener 60 of the first fixing portion 21 of the ceiling panel 1 adjacent to the second edge portion 10b side of the ceiling panel 1 to be removed. Loosen the fasteners 60 of the second fixing portions 41 of the ceiling panel 1 to be removed. The fasteners 60 of the first fixing portions 21 of the ceiling panel 1 to be removed are removed. The first edge portion 10a of the ceiling panel 1 to be removed is moved downward to tilt the ceiling panel 1, and the ceiling panel 1 is then slid obliquely downward.

[0126] 12, it is necessary to loosen the fasteners 60 of the first fixing portions 21 of the adjacent panel, which differs from the method of removing the ceiling panels in FIGS. 9 and 11. However, it is not necessary to remove the fasteners 60 of the second fixing portions 41 of the ceiling panel 1 to be removed either, as they only need to be loosened, allowing for efficient removal.

[0127] In the ceiling panel 1 shown in Fig. 8, the relationship between the height position of the protrusions 25b, 25c that abut against the base portion 71 of the joist 70 and the height position of the first fixing portion 21 is set to a predetermined height relationship in order to form the gap S1. However, the other protrusions 45b shown in Fig. 8 and the protrusions 25b, 25c, and 45b shown in Fig. 12 do not have to abut against the base portion 71 and may not be provided. In particular, in the embodiments shown in Figs. 12 and 13, the ceiling panel 1 of Fig. 4 may be used instead of the ceiling panel 1 of Fig. 12.

[0128] Of course, in order to stably attach the ceiling panel 1 to the joist 70, it is desirable to use a ceiling panel 1 having fixing pieces in which the protrusions 25b, 25c, 45b abut against the joist 70, as shown in Figures 8 and 12. [Explanation of symbols]

[0129] 1 Ceiling Panel 10 Panel body 10a First margin 10b Second margin 20 1st fixed piece 21 1st fixed part 22 First projection 22a First slot (notch) 23 First Recess 25b, 25c protrusion 40 Second fixed piece 41 Second fixed part 42 Second projection 42a Second slot 42b open hole 43 Second recess 45b Protrusion 60 Fastener 65 Reinforcement piece 70 Ceiling base (rough lining)

Claims

1. A ceiling panel having a flat panel body having a rectangular outer shape in a plan view, and a first edge portion and a second edge portion located on both sides of one direction of the panel body being fixed to a ceiling substrate, The first edge portion of the panel body is provided with a first fixing portion that is fixed to the ceiling substrate by a fastener along the longitudinal direction of the first edge portion, a second fixing portion that is fixed to the ceiling substrate by a fastener along the longitudinal direction of the second edge portion of the panel body; The first fixing portion includes a first protruding piece whose back surface faces and is close to a part of the second fixing portion of the adjacent ceiling panel, and a first recess that exposes a part of the second fixing portion of the adjacent ceiling panel, The second fixing portion is characterized by comprising: a second protrusion having a surface that faces and is close to the first protrusion of an adjacent ceiling panel and a surface that can be partially exposed by the first recess of the adjacent ceiling panel; and a second recess that is blocked by the first protrusion of the adjacent ceiling panel.

2. In claim 1, A ceiling panel characterized in that multiple pairs of the first protrusions and the first recesses are alternately provided on the first edge portion, and multiple pairs of the second protrusions and the second recesses are provided on the second edge portion.

3. In claim 1 or 2, The ceiling panel is characterized in that the first protrusion and the second protrusion are disposed at a height position on the rear side of the panel body.

4. In any one of claims 1 to 3, A ceiling panel characterized in that a first long hole for inserting a fastener is provided in the first protrusion at a position corresponding to the second recess of the ceiling panel adjacent to the first edge portion, the first long hole extending in a direction perpendicular to the longitudinal direction of the first edge portion.

5. In any one of claims 1 to 4, A ceiling panel characterized in that a second elongated hole for inserting a fastener is provided in the second protrusion at a position corresponding to the first recess of the ceiling panel adjacent to the second edge portion, the second elongated hole extending along the longitudinal direction of the second edge portion.

6. In any one of claims 1 to 5, A ceiling panel characterized in that the first fixing portion has a protrusion on the panel body side that abuts against the ceiling substructure and maintains the distance between the first fixing portion and the ceiling substructure at a dimension that exceeds the thickness of the second protrusion.

7. In any one of claims 1 to 4, A ceiling panel characterized in that an open hole for inserting a fastener is provided in the second protruding piece at a position corresponding to the first recess of the ceiling panel adjacent to the second edge portion.

8. In claim 7, A ceiling panel characterized in that a protrusion is provided on the panel body side of the first fixing portion, which abuts against the ceiling substructure and maintains the distance between the first fixing portion and the ceiling substructure at a dimension that exceeds the thickness of the second protrusion.

9. A panel removal method for removing one ceiling panel from between a ceiling panel on the first edge side and a ceiling panel on the second edge side when a plurality of ceiling panels according to any one of claims 1 to 5 are attached to the ceiling substrate, Loosen the fastener of the first fixing portion of the ceiling panel adjacent to the second edge portion side of the ceiling panel to be removed; Remove the fastener of the second fixing portion of the ceiling panel to be removed; Remove the fastener of the first fixing portion of the ceiling panel to be removed; A panel removal method, comprising: moving the first edge portion of the ceiling panel to be removed downward to tilt the ceiling panel, and then sliding the ceiling panel diagonally downward.

10. A panel removal method for removing one ceiling panel from between the ceiling panel on the first edge side and the ceiling panel on the second edge side when a plurality of ceiling panels according to claim 6 are attached to the ceiling substrate, comprising: Remove the fastener of the second fixing portion of the ceiling panel to be removed; Remove the fastener of the first fixing portion of the ceiling panel to be removed; A panel removal method, comprising: moving the first edge portion of the ceiling panel to be removed downward to tilt the ceiling panel, and then sliding the ceiling panel diagonally downward.

11. A panel removal method for removing one ceiling panel from between the ceiling panel on the first edge side and the ceiling panel on the second edge side when a plurality of ceiling panels according to claim 7 are attached to the ceiling substrate, comprising: Loosen the fastener of the first fixing portion of the ceiling panel adjacent to the second edge portion side of the ceiling panel to be removed; Loosen the fastener of the second fixing portion of the ceiling panel to be removed; Remove the fastener of the first fixing portion of the ceiling panel to be removed; A panel removal method, comprising: moving the first edge portion of the ceiling panel to be removed downward to tilt the ceiling panel, and then sliding the ceiling panel diagonally downward.

12. A panel removal method for removing one ceiling panel from between the ceiling panel on the first edge side and the ceiling panel on the second edge side when a plurality of ceiling panels according to claim 8 are attached to the ceiling substrate, comprising: Loosen the fastener of the second fixing portion of the ceiling panel to be removed; Remove the fastener of the first fixing portion of the ceiling panel to be removed; A panel removal method, comprising: moving the first edge portion of the ceiling panel to be removed downward to tilt the ceiling panel, and then sliding the ceiling panel diagonally downward.

Images