Inspection hatch

Abstract

With a simple structure, it ensures airtightness between the inner and outer frames when closed, while also facilitating the opening and closing of the inner frame. [Solution] The inspection opening 10 has an outer frame 20 fixed to an opening 91 provided on the installation surface 90, an inner frame 30 installed inside the outer frame 20, a pair of hinge members 50 that pivotally support the inner frame 30 so as to be rotatable, and a packing that seals the space between the inner frame 30 and the outer frame 20. On the front side of the rear flange 25 of the outer frame on one outer frame material 21, there is a first rib 71 that extends to a position facing the rear flange 35 of the inner frame on one inner frame material 31 when the inner frame 30 is in a closed position relative to the outer frame 20. The packing has a first packing 61 provided on the inward side of the first rib 71 of the one outer frame material 21 and pressed against the outward side of the rear flange 35 of the inner frame, and a second packing 62 provided on the front side of the rear flange 25 of the outer frame on three outer frame material 23 and pressed against the rear side of the rear flange 35 of the inner frame.

Description

Technical Field

[0006]

[0001] The present invention relates to an inspection port.

Background Art

[0002] An inspection port having an outer frame and an inner frame is disclosed (see Patent Document 1). The inner edges of the outer frame and the inner frame on the indoor side are each made narrow. In this inspection port, in order to enhance the airtightness between the outer frame and the inner frame when closed and enable the inner frame to be opened and closed, a slide bar is provided on the inner frame, and the rotation axis of the slide bar moves in the pivot hole portion of the outer frame. Further, the crank portion of the inner frame abuts against the packing provided on the crank portion of the outer frame in the inner-outer direction of the opening.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the above-described conventional example, in order to enable the inner frame to be opened and closed while the inner frame abuts against the packing provided on the crank portion of the outer frame in the inner-outer direction of the opening, the slide bar slides the inner frame, and a configuration in which the rotation axis of the slide bar moves in the pivot hole portion of the outer frame is adopted, etc., the configuration is complicated and the cost is high. Further, since there is a knack in the opening and closing operation of the inner frame, it may take time to open and close the inner frame if one is not used to it.

[0005] An object of the present invention is to facilitate the opening and closing of the inner frame while ensuring the airtightness between the inner frame and the outer frame when closed with a simple configuration.

Means for Solving the Problems

[0006] An inspection opening according to the first embodiment comprises a rectangular outer frame fixed to an opening provided in the installation surface, an inner frame installed inside the outer frame and having a lid material inside, a pair of hinge members connecting the outer frame and the inner frame and pivotally supporting the inner frame so that it can rotate, and a packing that seals the space between the inner frame and the outer frame, wherein the outer frame comprises a one-sided outer frame material that forms one side of the rectangular shape and a three-sided outer frame material that forms the remaining three sides of the rectangular shape. The one outer frame member and the three outer frame member each have an outer frame plate portion extending from the front side to the back side of the opening and an outer frame rear flange provided on the rear side of the outer frame plate portion, and the inner frame has a one inner frame member forming one side of the rectangular shape and three inner frame members forming the remaining three sides of the rectangular shape, and the one inner frame member and the three inner frame members each have an inner frame plate portion extending from the front side to the back side and an inner frame rear flange provided on the rear side of the inner frame plate portion, With the inner frame in a closed position relative to the outer frame, the outer frame rear flange extends inward to the vicinity of the inner frame rear flange, and the hinge member is fixed to at least one of the outer frame plate portions of the one outer frame material and the three outer frame material adjacent to the one outer frame material, and a first rib is provided on the front side of the outer frame rear flange of the one outer frame material, extending to a position facing the inner frame rear flange of the one inner frame material when the inner frame is in a closed position relative to the outer frame, and the packing comprises a first packing provided on the inner side of the first rib of the one outer frame material and pressed against the outer side of the inner frame rear flange when the inner frame is in a closed position relative to the outer frame, and a second packing provided on the front side of the outer frame rear flange of the three outer frame material and pressed against the rear side of the inner frame rear flange when the inner frame is in a closed position relative to the outer frame.

[0007] In this inspection hatch, an inner frame, which has a lid inside, is pivotally supported by a hinge member that connects the inner and outer frames. The inspection hatch can be easily opened and closed by the rotation of this inner frame relative to the hinge member. When the inner frame is in the closed position relative to the outer frame, the first packing is pressed against the outer surface of the inner frame's rear flange, and the second packing is pressed against the rear side surface of the inner frame's rear flange. As a result, even with a simple structure in which the inner frame rotates relative to the hinge member, airtightness is ensured on all four sides between the inner and outer frames when closed.

[0008] A second embodiment provides an inspection opening according to the first embodiment, wherein the hinge member includes a mounting piece fixed to the inner surface of the outer frame plate portion of at least one of the one outer frame member and the three outer frame member adjacent to the one outer frame member; a rotating shaft provided on the inner frame plate portion of the three inner frame member adjacent to the one inner frame member, which serves as the rotation center of the inner frame; and a shaft support piece positioned in the gap between the three outer frame member and the three inner frame member to support the rotating shaft.

[0009] In this inspection hatch, the inner frame rotates relative to the hinge member, allowing the inner frame to be easily opened and closed relative to the outer frame.

[0010] In the third embodiment, in the inspection opening according to the second embodiment, a receiving portion is provided on the inner surface of the outer frame plate portion of the one outer frame member or the three outer frame member adjacent to the one outer frame member, which allows the mounting piece of the hinge member to be temporarily supported from the front side during assembly.

[0011] This inspection hatch improves the workability when fixing the mounting piece to the outer frame.

[0012] The fourth embodiment is an inspection opening according to the third embodiment, wherein the outer frame plate portion of the one outer frame member or the three outer frame member adjacent to the one outer frame member is provided with a stopper portion that, when the hinge member is temporarily supported by the receiving portion, contacts the mounting piece or the shaft support piece of the hinge member and prevents the hinge member from tipping over.

[0013] This inspection hatch improves the workability when fixing the mounting piece to the outer frame.

[0014] The fifth embodiment is an inspection opening according to the fourth embodiment, wherein the stopper is the first rib of the one outer frame material, and when the hinge member is temporarily supported by the receiving portion, the inside of the mounting piece of the hinge member abuts against the outside of the first rib of the one outer frame material, thereby suppressing the tilting of the hinge member.

[0015] In this inspection opening, the first rib can also function as a fastening point.

[0016] The sixth embodiment is an inspection opening according to any one of the first to fifth embodiments, wherein a second rib is provided on the front side of the rear flange of the outer frame of the three-sided outer frame member, extending to a position facing the rear flange of the inner frame of the three-sided inner frame member when the inner frame is in a closed position relative to the outer frame.

[0017] In this inspection opening, when the inner frame is in the closed position relative to the outer frame, the portion of the second packing that is not pressed against the rear side surface of the inner frame's rear flange can be formed to fit between the outer surface of the inner frame's rear flange and the inner surface of the second rib. This further enhances the airtightness between the inner frame and the outer frame when closed. [Effects of the Invention]

[0018] According to the present invention, it is possible to easily open and close the inner frame while ensuring airtightness between the inner frame and the outer frame when closed, with a simple configuration. [Brief explanation of the drawing]

[0019] [Figure 1] This is a perspective view showing the inspection hatch in the open position according to this embodiment. [Figure 2] This is a cross-sectional view corresponding to the view taken by arrow 2-2 in Figure 1, showing the inspection opening according to this embodiment. [Figure 3] This is a cross-sectional view corresponding to the view taken by arrow 3-3 in Figure 1, showing the inspection opening according to this embodiment. [Figure 4] It is a partially broken perspective view showing the structure near the hinge member when the inner frame is opened. [Figure 5] It is a partially broken perspective view showing the structure near the hinge member when the inner frame is in the closed position. [Figure 6] It is a cross-sectional view showing the state when the inner frame is opened. [Figure 7] It is a cross-sectional view showing the state when the inner frame is in the closed position. [Figure 8] It is a cross-sectional view showing the state in which the attachment piece of the hinge member is brought close to the outer frame plate portion of one outer frame member in the process of assembling the inner frame to the outer frame. [Figure 9] Following FIG. 8, it is a cross-sectional view showing the state in which the attachment piece of the hinge member is overlapped with the outer frame plate portion of one outer frame member. [Figure 10] Following FIG. 9, it is a cross-sectional view showing the state in which the attachment piece of the hinge member is temporarily supported by the receiving portion. [Figure 11] It is a cross-sectional view showing the state in which when the attachment piece temporarily supported by the receiving portion is tilted due to the self-weight of the inner frame, it abuts against the first rib as the stopping portion and further tilting is suppressed. [Figure 12] It is an exploded perspective view showing the coupling structure of the outer frame and the inner frame. [Figure 13] It is a cross-sectional view showing the state when the inner frame is in the closed position. [Figure 14] In the inspection opening according to the modification example, it is a cross-sectional view showing the state in which when the attachment piece temporarily supported by the receiving portion is tilted due to the self-weight of the inner frame, it abuts against the bolt as the stopping portion and further tilting is suppressed. [[ID=3-four]]

Mode for Carrying Out the Invention

[0020] The embodiments for carrying out the present invention will be described below with reference to the drawings. Components indicated by the same reference numerals in each drawing are the same or similar components. In the embodiments described below, descriptions and reference numerals that are repeated may be omitted. Furthermore, the drawings used in the following description are all schematic, and the dimensional relationships and ratios of each element shown in the drawings do not necessarily correspond to reality. Also, the dimensional relationships and ratios of each element do not necessarily correspond between multiple drawings.

[0021] In Figures 1 to 13, the inspection hatch 10 according to this embodiment has a structure in which an inner frame 30 is attached inside an outer frame 20. This inspection hatch 10 comprises an outer frame 20, an inner frame 30, a pair of hinge members 50, and, as an example of packing, a first packing 61 and a second packing 62. Figure 1 shows the outer frame 20 attached to the ceiling (Figures 2 and 3), which is the installation surface 90, and the inner frame 30 in an open state, as viewed from above the ceiling. In this embodiment, the direction of the back side of the installation surface 90 is referred to as the "back side," and the direction of the front side of the installation surface 90 is referred to as the "front side."

[0022] The outer frame 20 is a rectangular, for example, metal member fixed to an opening 91 provided in the installation surface 90. The outer frame 20 has one outer frame member 21 that forms one side of the rectangle and three outer frame members 23 that form the remaining three sides of the rectangle. The one outer frame member 21 and the three outer frame members 23 each have an outer frame plate portion 24 that extends from the front side to the back side of the opening 91 and an outer frame rear flange 25 provided on the rear side of the outer frame plate portion 24. The outer frame plate portion 24 may be provided with a stepped portion 22 that extends in the longitudinal direction of the outer frame plate portion 24.

[0023] The inner frame 30 is a rectangular metal member installed inside the outer frame 20, with a lid material 40 provided inside. The inner frame 30 has one inner frame material 31 that forms one side of the rectangle, and three inner frame materials 33 that form the remaining three sides of the rectangle. The one inner frame material 31 and the three inner frame materials 33 each have an inner frame plate portion 34 that extends from the front to the back, and an inner frame rear flange 35 provided on the rear side of the inner frame plate portion 34. The inner frame plate portion 34 may be provided with a stepped portion 32 that extends in the longitudinal direction of the inner frame plate portion 34.

[0024] As shown in Figure 7, with the inner frame 30 in a closed position relative to the outer frame 20, the outer frame rear flange 25 extends inward to the vicinity of the inner frame rear flange 35. On the other hand, a first rib 71 is provided on the front side of the outer frame rear flange 25 of the outer frame material 21. This first rib 71 is the portion that extends to a position opposite the inner frame rear flange 35 of the inner frame material 31 when the inner frame 30 is in a closed position relative to the outer frame 20.

[0025] The pair of hinge members 50 are members that connect the outer frame 20 and the inner frame 30 and pivotally support the inner frame 30 so that it can rotate. The hinge members 50 are fixed to at least one of the outer frame plate portions 24 of the one outer frame member 21 and the three outer frame members 23 adjacent to the one outer frame member 21, in this embodiment both outer frame plate portions 24. The hinge member 50 has a mounting piece 51, a rotation shaft 54, and a shaft support piece 53.

[0026] The mounting piece 51 is fixed to the inner surface of at least one outer frame plate portion 24 of the one outer frame member 21 and the three outer frame member 23 adjacent to the one outer frame member 21. In this embodiment, the mounting piece 51 is fixed to the inner surface of the outer frame plate portion 24 of the one outer frame member 21 by, for example, two screws 52. The mounting piece 51 is also fixed to the inner side of the stepped portion 22 of the one outer frame member 21. The mounting piece 51 may also be fixed to the inner surface of the outer frame plate portion 24 of the three outer frame member 23 adjacent to the one outer frame member 21. Alternatively, the mounting piece 51 may be fixed to the inner surface of all outer frame plate portions 24 of the one outer frame member 21 and the three outer frame member 23 adjacent to the one outer frame member 21.

[0027] The rotating shaft 54 ​​is provided on the inner frame plate portion 34 of the three-sided inner frame member 33 adjacent to the one-sided inner frame member 31, and is the member that serves as the rotation center of the inner frame 30. This rotating shaft 54 ​​is, for example, a hollow rivet. The rotating shaft 54 ​​is also located on the front side of the stepped portion 22 of the outer frame 20 in the gap between the three-sided outer frame member 23 and the three-sided inner frame member 33. The shaft support piece 53 is positioned in the gap between the three-sided outer frame member 23 and the three-sided inner frame member 33 and is the part that rotates and supports the rotating shaft 54. The shaft support piece 53 is formed by bending, for example, at a right angle to the mounting piece 51. The bent portion is reinforced, for example, by a rib 56. The inner frame 30 is rotatably supported between an open state and a closed state by the shaft support piece 53 of the hinge member 50.

[0028] In Figures 6 and 7, on the inner surface of the outer frame plate portion 24 of the outer frame material 21, a support portion 26 is provided that allows the mounting piece 51 of the hinge member 50 to be temporarily supported from the front side during assembly. The support portion 26 is constructed by providing a cantilevered L-shaped cross section on the inner surface of the outer frame plate portion 24. The support portion 26 is open at the rear. The distance between the tip of the support portion 26 and the rear flange 25 of the outer frame is set to be greater than the height dimension of the mounting piece 51 of the hinge member 50. This makes it possible to insert the upper part of the mounting piece 51 of the hinge member 50 into the support portion 26 first, and then insert the lower part of the mounting piece 51 into the support portion 26 to temporarily support it when assembling the inner frame 30 to the outer frame 20 (Figures 8 to 10).

[0029] The gap in the receiving portion 26 is slightly larger than the thickness of the mounting piece 51 on the hinge member 50. This allows the lower part of the mounting piece 51 to be easily inserted into the receiving portion 26 when assembling the inner frame 30 to the outer frame 20. In addition, the mounting piece 51 can tilt within the range of the gap in the receiving portion 26. This allows for a certain degree of tilting of the hinge member 50 when it is temporarily supported (Figure 11).

[0030] As shown in Figure 12, in this embodiment, a screw hole 27A is provided in the corner component 27 that connects the one outer frame member 21 and the three outer frame members 23 in a rectangular shape. The outer frame plate portion 24 of the one outer frame member 21 is provided with a through hole corresponding to the screw hole 27A. The hinge member 50 is fastened and fixed to the one outer frame member 21 by screwing a screw 52 through this through hole into the screw hole 27A.

[0031] On the other hand, the outer frame material 21 is provided with a first rib 71 as an example of a fastening part. This first rib 71 is a part that the mounting piece 51 of the hinge member 50 comes into contact with when the hinge member 50 is temporarily supported by the receiving part 26, thereby suppressing the tilting of the hinge member 50. Specifically, when the mounting piece 51 of the hinge member 50 tries to tilt inward when the hinge member 50 is temporarily supported by the receiving part 26, the upper part of the mounting piece 51 comes into contact with the outer surface of the first rib 71. This suppresses the tilting of the hinge member 50.

[0032] A second rib 72 is provided on the front side of the rear flange 25 of the outer frame member 23. This second rib 72 extends to a position facing the rear flange 35 of the inner frame member 33 when the inner frame 30 is in a closed position relative to the outer frame 20. The protruding width of the first rib 71 is longer than the protruding width of the second rib 72 of the outer frame member 23.

[0033] In Figures 4 to 7, the first packing 61 and the second packing 62 are sealing members that seal the space between the inner frame 30 and the outer frame 20. The first packing 61 is provided on the inner side of the first rib 71 of the outer frame material 21. This first packing 61 is pressed against the outer side of the inner frame rear flange 35 when the inner frame 30 is in the closed position relative to the outer frame 20. The second packing 62 is provided on the front side of the outer frame rear flange 25 of the three-sided outer frame material 23. This second packing 62 is pressed against the rear side of the inner frame rear flange 35 when the inner frame 30 is in the closed position relative to the outer frame 20. The second packing 62 is provided, for example, on substantially the entire surface of the outer frame rear flange 25 inside the second rib 72. The width of the inner frame rear flange 35 is smaller than the width of the second packing 62. Therefore, as shown in Figure 5, when the inner frame 30 is in the closed position relative to the outer frame 20, the portion of the second packing 62 that is not crushed by the inner frame rear flange 35 fits between the outer surface of the inner frame rear flange 35 and the inner surface of the second rib 72. This further improves the airtightness between the three-sided outer frame material 23 and the three-sided inner frame material 33.

[0034] In Figures 2 and 3, on the installation surface 90 where the inspection hatch 10 is provided, a finishing material 93 is attached to the interior side of the base material 92 on the ceiling side, and a rectangular opening 91 is provided therein. Of the multiple furring strips 94 provided parallel to two parallel sides of the opening 91, some furring strips 94 that abut against two other parallel sides of the opening 91 are interrupted at the opening 91. Also, furring strip supports 95 provided perpendicular to the furring strips 94 are placed above the furring strips 94 and are supported by suspension bolts 99 from the ceiling structure via hangers 96. The outer frame 20 is attached to the inner circumference of the opening 91 via channel catches 98 to a channel 97 provided perpendicular to the furring strip supports 95. The outer frame 20 is fixed to the channel catches 98 with frame fixing screws 21B.

[0035] In Figures 2 and 3, the lid material 40 fitted inside the inner frame 30 is composed of a base material 41 on the ceiling side and a finishing material 42 on the interior side. The base material 41 is screw-fastened to the inner frame 30 via a finishing material retainer 37. In addition, one of the two opposing sets of finishing material retainers 37 may be reinforced with a reinforcing material (not shown). The inner frame 30 is attached to the outer frame 20 via a hinge member 50. A lock 36 is attached to the center of the rotating end of the inner frame 30, which is opposite the position of the hinge member 50. When the inspection opening 10 fitted in the opening 91 of the installation surface 90 is closed, the outer frame 20 and the inner frame 30 are in close contact via the first packing 61 and the second packing 62, and the closed state is stably maintained by locking them with the lock 36 on one side.

[0036] Specifically, when the inner frame 30 is closed against the outer frame 20, the inner frame's rear flange 35 slightly presses against the first packing 61 and the second packing 62 of the outer frame 20. When the lock 36 of the inner frame is locked, the inner frame's rear flange 35 crushes the first packing 61 and the second packing 62, thereby ensuring airtightness between the outer frame 20 and the inner frame 30.

[0037] Furthermore, in Figure 13, an elongated hole 34A for passing a screw 75 is formed in the inner frame plate portion 34 so that the mounting position of the finishing material retainer 37 can be adjusted depending on the difference in thickness of the lid material 40. To further improve airtightness, holes such as this elongated hole 34A may be sealed with a seal 74.

[0038] (action) This embodiment is configured as described above, and its operation will be explained below. In Figures 1 to 7, in the inspection opening 10 according to this embodiment, an inner frame 30, which has a lid material 40 inside, is pivotally supported by a hinge member 50 that connects the outer frame 20 and the inner frame 30. The inspection opening 10 can be easily opened and closed by the rotation of this inner frame 30 relative to the hinge member 50. On the other hand, a first rib 71 is provided on the front side of the rear flange 25 of the outer frame material 21. This first rib 71 extends to a position facing the rear flange 35 of the inner frame material 31 when the inner frame 30 is in the closed position relative to the outer frame 20. In addition, a first packing 61 and a second packing 62 are provided as packings. The first packing 61 is provided on the inner side of the first rib 71 of the outer frame material 21. The second packing 62 is provided on the front side of the rear flange 25 of the outer frame of the three-sided outer frame material 23. With the inner frame 30 in the closed position relative to the outer frame 20, the first packing 61 is pressed against the outer surface of the inner frame's rear flange 35, and the second packing 62 is pressed against the rear side surface of the inner frame's rear flange 35. As a result, even with a simple structure in which the inner frame 30 rotates relative to the hinge member 50, airtightness is ensured on all four sides between the inner frame 30 and the outer frame 20 when closed.

[0039] Furthermore, the hinge member 50 has a mounting piece 51, a rotating shaft 54, and a shaft support piece 53. The hinge member 50 is fixed to the inner surface of the outer frame plate portion 24 of the one outer frame member 21 at the mounting piece 51. The rotating shaft 54 ​​is provided on the inner frame plate portion 34 of the three inner frame member 33 adjacent to the one inner frame member 31, and serves as the rotation center of the inner frame 30. The shaft support piece 53 is positioned in the gap between the three outer frame member 23 and the three inner frame member 33, and supports the rotating shaft 54. By rotating the inner frame 30 relative to the hinge member 50, the inner frame 30 can be easily opened and closed relative to the outer frame 20.

[0040] Furthermore, as shown in Figures 8 to 11, the receiving portion 26 provided on the inner surface of the outer frame plate portion 24 of the outer frame material 21 allows the mounting piece 51 of the hinge member 50 to be temporarily supported from the front side during assembly. This improves the workability when fixing the mounting piece 51 to the outer frame 20.

[0041] Furthermore, when the hinge member 50 is temporarily supported by the receiving portion 26, the mounting piece 51 of the hinge member 50 comes into contact with the first rib 71, which is provided on the outer frame material 21 as a stopper, thereby suppressing the tilting of the hinge member 50. Specifically, when the hinge member 50 is temporarily supported by the receiving portion 26, the inner surface of the mounting piece 51 of the hinge member 50 comes into contact with the outer surface of the first rib 71 of the outer frame material 21. This improves the workability when fixing the mounting piece 51 to the outer frame 20.

[0042] Furthermore, when the inner frame 30 is in the closed position relative to the outer frame 20, the portion of the second packing 62 that is not pressed against the rear side surface of the inner frame rear flange 35 can be formed to fit between the outer surface of the inner frame rear flange 35 and the inner surface of the second rib 72. This further enhances the airtightness between the inner frame 30 and the outer frame 20 when closed.

[0043] According to this embodiment, with a simple configuration, it is possible to easily open and close the inner frame 30 while ensuring airtightness between the inner frame 30 and the outer frame 20 when closed.

[0044] [Other embodiments] Although an example of an embodiment of the present invention has been described above, the embodiments of the present invention are not limited to those described above, and it goes without saying that various modifications can be made and implemented without departing from the spirit of the invention.

[0045] The inspection hatch 10 is not limited to being installed in the ceiling, but may also be installed in the wall. The outer frame 20 and inner frame 30 are not limited to being made of metal, but may also be made of synthetic resin or the like.

[0046] The fastening portion is not limited to the first rib 71. As shown in the modified example in Figure 14, a bolt 73 may be provided as an example of a fastening portion on the outer frame plate portion 24 of the three outer frame member 23 adjacent to the one outer frame member 21. The axial support piece 53 of the hinge member 50 may contact the head of the bolt 73 to suppress the tilting of the hinge member 50. In this modified example, the protruding width of the first rib 71 of the one outer frame member 21 is equal to the protruding width of the second rib 72 of the three outer frame member 23. [Explanation of Symbols]

[0047] 10 Inspection hatches 20 Outer frame 21. Outer frame material 23 Three-sided outer frame material 24 Outer frame plate section 25 Outer frame rear flange 26 Receiving part 30 Inner frame 31 One side inner frame material 33 Three-sided inner frame material 34 Inner frame plate section 35 Inner frame rear flange 40 Lid material 50 Hinge components 51 Mounting piece 53 Shaft support piece 54 Rotation axis 61. First packing (packing) 62. Second packing (packing) 71 First rib (fastening part) 72. Second Rib 73 Bolts (for fastening)

Claims

1. A rectangular outer frame fixed to an opening provided on the mounting surface, An inner frame is installed inside the outer frame and has a lid inside, A pair of hinge members that connect the outer frame and the inner frame and pivotally support the inner frame so that it can rotate, A packing that seals the space between the inner frame and the outer frame, An inspection hatch equipped with, The outer frame comprises one outer frame member that forms one side of the rectangular shape, and three outer frame members that form the remaining three sides of the rectangular shape. The aforementioned one outer frame member and the aforementioned three outer frame member each have an outer frame plate portion extending from the front side to the back side of the opening and an outer frame rear flange provided on the rear side of the outer frame plate portion, The inner frame comprises one inner frame member that forms one side of the rectangular shape, and three inner frame members that form the remaining three sides of the rectangular shape. The aforementioned one inner frame member and the aforementioned three inner frame member each have an inner frame plate portion extending from the front side to the back side, and an inner frame rear flange provided on the rear side of the inner frame plate portion, With the inner frame in a closed position relative to the outer frame, the rear flange of the outer frame extends inward to the vicinity of the rear flange of the inner frame. The hinge member is fixed to at least one of the outer frame plate portions of the one outer frame member and the three outer frame members adjacent to the one outer frame member. A first rib is provided on the front side of the rear flange of the outer frame of the one outer frame member, extending to a position facing the rear flange of the inner frame of the one inner frame member when the inner frame is in a closed position relative to the outer frame. The aforementioned packing is A first packing is provided on the inner surface of the first rib of the one outer frame material and is pressed against the outer surface of the inner frame rear flange when the inner frame is in a closed position relative to the outer frame, A second packing is provided on the front surface of the rear flange of the outer frame of the three-sided outer frame material, and is pressed against the rear surface of the rear flange of the inner frame when the inner frame is in a closed position relative to the outer frame, An inspection hatch with a lid.

2. The inspection opening according to claim 1, wherein the hinge member comprises a mounting piece fixed to the inner surface of the outer frame plate portion of at least one of the one outer frame material and the three outer frame material adjacent to the one outer frame material, a rotating shaft provided on the inner frame plate portion of the three inner frame material adjacent to the one inner frame material and serving as the rotation center of the inner frame, and a shaft support piece disposed in the gap between the three outer frame material and the three inner frame material to support the rotating shaft.

3. The inspection opening according to claim 2, wherein the inner surface of the outer frame plate portion of the one outer frame member or the three outer frame member adjacent to the one outer frame member is provided with a receiving portion that allows the mounting piece of the hinge member to be temporarily supported from the front side during assembly.

4. The inspection opening according to claim 3, wherein the outer frame plate portion of the one outer frame member or the three outer frame member adjacent to the one outer frame member is provided with a stopper portion that, when the hinge member is temporarily supported by the receiving portion, contacts the mounting piece or the shaft support piece of the hinge member to suppress the tilting of the hinge member.

5. The inspection opening according to claim 4, wherein the stopper is the first rib of the one outer frame material, and when the hinge member is temporarily supported by the receiving portion, the inner side of the mounting piece of the hinge member abuts against the outer surface of the first rib of the one outer frame material, thereby suppressing the tilting of the hinge member.

6. The inspection opening according to any one of claims 1 to 5, wherein a second rib is provided on the front side of the rear flange of the outer frame in the three-sided outer frame member, extending to a position facing the rear flange of the inner frame of the three-sided inner frame member when the inner frame is in a closed position relative to the outer frame.

Images