JP2000204748A - Ceiling inspection door - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a stopper at an inspection door which enables arbitrary change of the direction of a swing base side. SOLUTION: A plastic stopper 30 having an inward projection 32 is fitted removably to the inside of an outer frame 1, while an upward contact face is formed on the outside of an inner frame so that the contact face comes into contact with the projection 32 of the stopper 30 and stops the rotation of the inner frame when this frame rotates in respect to the outer frame 1 and closes. Since the stopper 30 is fitted removably to the inside of the outer frame, it can be fitted to a proper side of the outer frame 1 after the direction of a swing base side is set.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a ceiling for a building,
It relates to a ceiling inspection port installed for inspection and repair work of the ceiling.

[0002]

2. Description of the Related Art A ceiling inspection opening comprises an outer frame and an inner frame which is detachable from the outer frame. First, the outer frame is attached to the ceiling, the inner frame is pivotally supported on the inner surface of the outer frame, and the inner frame is removed. It opens and closes by rotating with respect to the frame. Both the outer frame and the inner frame are usually assembled with a metal material such as aluminum, and the same frame material as the ceiling plate is attached to the inner frame.

In a conventional ceiling inspection port, a shaft pin is formed protruding near an inner end of two opposite sides of an outer frame, and an inner entrance is formed near an end of two opposite sides of an inner frame. A bearing groove is formed, and the inner frame is supported by the outer frame so that the shaft pin of the outer frame is inserted into the bearing groove of the inner frame, and the inner frame is opened and closed by rotating with respect to the outer frame. Is what you do.

[0004] There are only two shaft pins provided on the outer frame, and therefore, only one fixed position (so-called "hanger") supporting the inner frame is provided.

FIGS. 21 to 26 show examples of a conventional ceiling inspection port. FIG. 21 is a top view of an outer frame 70, and FIG.
23 and 24 are explanatory views for attaching the inner frame to the outer frame, FIG. 25 is a cross-sectional view showing the relationship between the outer frame and the inner frame in the shaft support, and FIG. 26 is the outer frame and the inner frame in the stopper portion. It is sectional drawing which shows the relationship of. This ceiling inspection door is outer frame 7
0 and an inner frame 71. The outer frame and the inner frame are each formed by assembling aluminum shapes into a square shape. As shown in FIG. 21, a shaft pin 72 is formed so as to protrude from inner surfaces of two opposing sides of the outer frame 70. Bearing grooves 73 are provided on outer surfaces of two opposing sides of the inner frame 71. As shown in FIG. 23, the inner frame 71 is vertically inserted into the outer frame 70, and the shaft pin 72 is inserted into the bearing groove 73. When the shaft pin 72 is at an appropriate position in the bearing groove 73, FIG.
As shown in FIG. 4, by rotating the inner frame 71 about the shaft pin 72, the inner frame can be opened and closed. When the inner frame 71 is closed, the pivot portion is as shown in FIG.

A stopper 74 is formed on the outer surface of the outer frame on the outer side of the two opposite sides where the shaft pin is formed, near the opposite end where the shaft pin is located. Stopper part 7
Reference numeral 4 denotes an aluminum frame material of the outer frame projected by press molding. As shown in FIG. 26, when the inner frame is rotated and closed, the contact surface of the inner frame (the upper surface of the bearing groove 73) comes into contact with the lower portion of the stopper portion 74, and the rotation stops.

[0007]

As described above, in the conventional ceiling inspection opening, the position for supporting the inner frame is fixed with respect to the outer frame. The original position is determined. For example, there are improper hanging locations near the walls and other ceiling fixtures. In such a place, the outer frame must be attached after confirming in which direction the suspension should be brought. However, in actual construction, after the outer frame is attached, it is often the first time that the direction of the suspension is found to be inappropriate, and the outer frame is often attached again.

In view of the above, there has been proposed a ceiling inspection port in which the position of the hanging base can be freely selected when the inner frame is mounted on the outer frame, and the hanging frame can be mounted in any direction. However, in this case, the stopper portion must be near the end of the side where the pivot portion is opposite to the pivot portion, regardless of the direction in which the hanging portion of the inner frame is opened in any direction. That is, it is necessary to protrude near all four ends of the outer frame, but in this case, the stopper portion of the side serving as a suspension becomes an obstacle when closing the inner frame, The inner frame cannot be closed. Therefore, there is a problem that a stopper cannot be provided.

In view of the above problems, the present invention provides a stopper for a ceiling inspection port in which the position of a hanging base can be freely selected when the inner frame is mounted on the outer frame and the hanging frame can be mounted in any direction. Can be provided.

[0010]

SUMMARY OF THE INVENTION The present invention has a square outer frame and an inner frame, and the outer side of the two opposing sides of the inner frame is pivotally supported inside the arbitrary two opposing sides of the outer frame. At the ceiling inspection opening, which can be opened and closed by rotating the inner frame with respect to the outer frame around the shaft support, a plastic stopper having a projecting portion that projects inward is attached to and detached from the inside of the outer frame. Attached freely, an upward contact surface is formed on the outside of the inner frame, and when the inner frame is rotated and closed with respect to the outer frame, the corresponding contact surface contacts the protrusion of the stopper. The ceiling inspection opening is characterized in that the rotation is stopped.

Since the stopper is detachably mounted inside the outer frame, the stopper can be mounted on an appropriate side of the outer frame after the direction of the hanging base is determined. In addition, since the stopper portion is conventionally formed by pressing the aluminum frame material of the outer frame and projecting, as shown in FIG. 26, the gap t between the tip of the stopper portion and the inner frame has to be considerably widened. This is because when the inner frame is closed, the stopper portion and the inner frame come into contact with each other and the inner frame cannot be closed smoothly. By making the stopper made of plastic, t can be made extremely small or zero due to its elasticity, and the inner frame is restrained by the stopper, thereby preventing rattling.

[0012] The ceiling inspection opening capable of opening the inner frame in an arbitrary direction is formed, for example, by forming a bearing groove having an inner entrance near both ends inside each side of the outer frame, and opposing two sides of the inner frame. A shaft pin protrudes near the end of the outer frame, and the shaft pin is inserted into the bearing groove on an arbitrary side of the outer frame to support the shaft. The bearing groove of the outer frame has a total of 8 near both ends of each side.
Since four places are provided, any of the four sides can be selected as a hanging point. If the bearing groove is formed so as to be inclined downward from the entrance toward the end, when the inner frame is attached to the outer frame, the shaft pin will smoothly enter the bearing groove by the weight of the inner frame, making it easy to work. It can be performed. Further, when the inner frame is opened and closed, the shaft pin is hard to move in the bearing groove, and rotates at the innermost lowermost portion of the bearing groove, so that the inner frame can be opened and closed smoothly.

In order to provide a removable stopper inside the outer frame, a C-shaped groove having a C-shaped cross section which opens inward is formed inside the outer frame.
The main plate has a main plate portion fitted into the shape groove, and a protruding portion protruding inward from the main plate portion. A horizontal flexible portion is formed in the main plate portion, and the flexible portion is bent into two upper and lower portions. Can be As shown in FIG. 12, by bending the main plate portion by the flexible portion, the stopper can be easily attached to and detached from the C-shaped groove.

Further, a C-shaped groove having a C-shaped cross section that opens inward is formed inside the outer frame, and the stopper has a main plate portion fitted into the C-shaped groove, and a stopper protrudes inward from the main plate portion. When the opening width of the C-shaped groove is w and the groove width is W, the height of the main plate portion is almost the same as or slightly smaller than the groove width W, and the lateral width is substantially the same as the opening width w. It may be small in size and notched so that diagonal corners of the main plate do not protrude outside the arc of diameter W. The stopper can be easily attached to the C-shaped groove by inserting the main plate into the C-shaped groove with the main plate portion lying down and rotating it 90 degrees in a predetermined direction. Also, it can be easily removed by rotating in the opposite direction.

Further, a ridge protruding inward is formed inside the outer frame, and the stopper is provided with two hinged plate members which are opened and closed. A notch is formed so that a space having a shape corresponding to the shape of the ridge is formed between the plate members, and the stopper is closed by sandwiching the stopper with the ridge and holding the ridge in the space. Can be easily attached to the outer frame. The stopper can be easily removed by opening the plate.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings showing embodiments. 1 is a top view of the ceiling inspection port of the embodiment, FIG. 2 is a perspective view of the outer frame 1, FIG. 3 is a partial cross-sectional view near an end of the outer frame 1, FIG. Fig. 6 is a partial side view of the vicinity of the end of the inner frame 11, Fig. 6 is a perspective view of the state where the inner frame 11 is mounted on the outer frame 1, Fig. 7 is an explanatory view of mounting the inner frame, and Fig. 8 is a cross section taken along line AA in Fig. 1. 9 is a perspective view of the corner member 3, FIG. 10 is a sectional view taken along the line BB in FIG. 1, FIG. 11 is a perspective view of the stopper 30, FIG. 12 is an explanatory view of attaching and detaching the stopper 30, and FIG. , FIG. 14 is an explanatory view of attachment / detachment of the stopper 40, FIG. 15 is a top view, a left side view, a front view of the stopper 50, FIG. 16 is a sectional view taken along the line DD in FIG. 19 is a front view of the stopper 55, FIG.
Is a perspective view of the stopper 60 in an open state, and FIG. 20 is a sectional view of the stopper 60 in a mounted state.

The ceiling inspection port of the embodiment comprises an outer frame 1 and an inner frame 11 mounted therein. The outer frame 1 is cut into a length of one side (the cut is at an angle of 45 degrees).
Are combined four. As shown in FIG. 3, the shape member 2 is formed in a substantially L-shape by a vertical plate portion 4 and a horizontal plate portion 5 protruding outward from a lower end thereof. A C-shaped groove 6 is formed inside the vertical plate portion 4. The C-shaped groove 6 has a tip 7a
The cross-sectional shape is substantially C-shaped by the upper ridge 7 having the upper ridge 7 and the lower ridge 8 having the tip 8b. A hook groove 9 is formed at the upper end of the vertical plate portion 4. 4 sections 2
Are assembled and integrated by inserting the corner material 3 into the end. The corner member 3 is inserted and fitted into the C-shaped groove 6. As shown in FIG. 9, the corner member 3 is formed by forming a plate member into an L-shape, and a bearing groove 10 having an inlet 10a at an end thereof is cut out at both ends. By providing the corner members 3 at the four corners, bearing grooves 10 having an inlet 10a inside are formed near both ends inside each side of the outer frame 1, and the number of the bearing grooves 10 is eight in total. The bearing groove 10 is inclined downward toward the inside (outside).

The inner frame 11 is formed by combining four profile members 12 each having a length of one side (a cut angle is 45 degrees). As shown in FIGS.
The vertical plate portion 13 and the horizontal plate portion 14 projecting inward and outward from the lower end thereof are formed in a substantially T-shape. A C-shaped groove 15 is formed outside the vertical plate portion 13. The C-shaped groove 15 has a ridge 16
The cross-sectional shape is substantially C-shaped due to the horizontal plate portion 14 and the horizontal plate portion 14.
The four mold members 12 are assembled and integrated by inserting the corner members 17 into the ends. Corner material 17 is C-shaped groove 1
5 and fit. The corner member 17 is formed by forming a plate member having a U-shaped cross section into an L shape.

As shown in FIGS. 1 and 4 and the like, a shaft pin 18 is formed protruding near the outer ends of two opposing sides of the inner frame 11. As shown in FIG. 8, the corner member 17 of the inner frame of the portion where the shaft pin 18 is mounted
A reinforcement boss portion 20 is provided so as to surround the periphery of the through hole 19 through which the hole is inserted. The reinforcing boss portion 20 is formed to be thick, and further has a cylindrical portion protruding inward. Thereby, the periphery of the through hole 19 is reinforced, and the shaft pin is stably supported without blurring. A flange portion 21 is formed near the rear end of the shaft pin 18. The shaft pin slides in the through hole 19 in the axial direction. The coil spring 22 is the shaft pin 1
8 to urge the shaft pin 18 toward the outer frame. Also, a latch 23 is provided on the inner frame 11, as shown in FIGS. The latch 23 is rotated by rotating a vertical axis. Such latches are known.

The inner opening of the inner frame 11 surrounded by the profile 12 is closed by mounting the same plate (not shown) as the ceiling plate on the horizontal plate 14.

The inner frame 11 is an outer frame 1 mounted on a ceiling.
Attached to. As shown in FIG. 7, the inner frame 11 is inserted into the outer frame 1 with the inner frame 11 in a vertical position, and the shaft pin 18 is inserted into the bearing groove 10 from the entrance 10a. Since the bearing groove 10 is inclined downward, the weight of the inner frame causes the shaft pin 18 to enter from the position of 18a shown by the dotted line to the deepest at the lower end of the bearing groove at the position of 18b shown by the solid line. As shown in FIG. 6, it is easily attached to the outer frame 1. Then, inner frame 1
1 is rotated as shown by the arrow C, the inner frame 11 is rotated around the shaft pin 18 and closed, and when the latch 23 is engaged, the completely closed state is maintained as shown in FIG. Dripping.
When the inner frame is opened, the latch 23 is rotated and released, and FIG.
It should just open in the state of. And the shaft pin 18 is in the bearing groove 1.
If the inner frame is moved so as to escape from 0, the inner frame can be easily removed.

Since the bearing grooves 10 of the outer frame 1 are provided at a total of eight positions near both ends of each side, the inner frame 11 can be mounted so that the suspension base is near an arbitrary side of the outer frame. .

The stopper 30 shown in FIGS. 10 to 12 has a main plate portion 31 fitted into the C-shaped groove 6 of the outer frame 1 and a projecting portion 32 projecting inward from the main plate portion 31. A flexible portion 33 is formed in the main plate portion 31 in the horizontal direction, and the flexible portion 33 bends into two upper and lower portions. In FIG. 11, the left side shows a state where the main plate portion is straightened, and the right side shows a state where the main plate portion is bent by the flexible portion. The flexible portion 33 is a thin film that integrally connects an upper portion and a lower portion thereof. As shown in FIG. 12, by bending the main plate portion 31 with the flexible portion 33, the stopper 30 can be easily attached to and detached from the C-shaped groove. When the inner frame 11 is closed, as shown in FIG. 10, the upper surface of the ridge 16 serves as the abutting surface 24 and abuts against the lower surface of the protrusion 32 of the stopper 30, and the rotation of the inner frame 11 stops.

The stopper 40 shown in FIGS. 13 and 14 has a main plate portion 41 fitted into the C-shaped groove 6 of the outer frame 1 and a protruding portion 42, 43 or 44 protruding inward from the main plate portion 41.
The projection 42 is formed at the upper part of the main plate part 41, 43 is formed at the center, and 44 is formed at the lower part. Assuming that the opening width of the C-shaped groove is w and the groove width is W, the height of the main plate portion 41 is slightly smaller than the groove width W, and the lateral width is slightly smaller than the opening width w. As shown in FIG. 13, the diagonal corners of the main plate portion 41 (the upper right corner and the lower left corner in this embodiment) are cut out so as not to protrude beyond the arc 46 having the diameter W. ing. When the protruding portion is formed above the main plate portion 41 like the protruding portion 42, a portion on the right side thereof (the side where the upper corner portion of the main plate portion is cut away).
Does not protrude beyond the arc 45 of the diameter w. When the projecting portion is formed at the center of the main plate portion 41 as in the case of the projecting portion 43, the whole of the projecting portion should not project beyond the arc 45 having the diameter w. When the protruding portion is formed at the lower portion of the main plate portion 41 like the protruding portion 44, the left side thereof (the side where the lower corner portion of the main plate portion is cut out) has an arc 45 having a diameter w.
So that it does not protrude. By doing this,
The stopper 40 can be rotated by 90 ° in the C-shaped groove 6 and can be attached to and detached from the C-shaped groove, at which time the protrusion does not hinder the rotation. That is, as shown on the left side of FIG. 14, the stopper 40 is inserted in the C-shaped groove with the stopper 40 lying sideways, and is rotated clockwise as shown on the right side from the center of the same figure, so that the stopper 40 is in the C-shaped groove. The stopper can be removed by rotating counterclockwise. The rotation of the stopper can be easily performed by pinching the protrusion with a finger. In the case where the above-described inner frame 11 is used as the inner frame, the position of the protruding portion adopts the position of the protruding portion 42 provided on the upper portion due to the position of the contact surface 24. When the inner frame 11 is closed, the lower surface of the protrusion 42 of the stopper 40 comes into contact with the contact surface of the inner frame 11, and the rotation of the inner frame 11 stops.

The stoppers 50 and 55 shown in FIGS.
Is rotated by the same principle as the stopper 40, and
It can be attached to and detached from the groove. In FIG. 15, the upper side shows a top view of the stopper 50, the left side shows a left side view, and the right side shows a front view. The height of the main plate portion 51 of the stopper 50 is slightly smaller than the groove width W, and the lateral width is slightly smaller than the opening width w. As shown in FIG.
The outer shape of 1 is cut out so as not to protrude outside the arc 46 having the diameter W. The right portion of the protruding portion 52 does not protrude from the arc 45 having the diameter w at the root thereof. However, at the tip end, as shown in FIGS. As described above, even if the distal end portion protrudes outward from the arc 45, it does not hinder rotation at the time of attachment and detachment. As shown on the left side of FIG. 17, the stopper 50 is inserted into the C-shaped groove with the stopper 50 laid down, and as shown on the right side from the center of the figure, the stopper 50 is fitted into the C-shaped groove by rotating clockwise. it can. At the position shown on the right side of the figure, the left side of the protrusion comes into contact with the tip 7a of the ridge 7 forming the C-shaped groove, and the rotation stops. Conversely, the stopper can be removed by turning counterclockwise. When the inner frame 11 is closed, the lower surface of the protrusion 52 of the stopper 50 comes into contact with the contact surface 24 of the inner frame 11, and the rotation of the inner frame 11 stops.

A stopper 55 shown in FIG. 18 is substantially the same as the stopper 50 described above, except that an elastic projection 57 is formed at the upper end of the main plate portion 56. The elastic projection 57 is elastically deformed in the vertical direction by the action of the notch 58, and has an effect of pressing the inner wall of the C-shaped groove and stabilizing the stopper when attached to the C-shaped groove.

A stopper 60 shown in FIG. 19 opens and closes two pieces of plate bodies 61 and 62 which are hinged. Plate 6
In each of the first and second plates 62, a space having a shape corresponding to the shape of the ridge 7 forming the C-shaped groove inside the outer frame is formed between the two pieces of the plate members 61 and 62 when closed. Notches 63 and 64 are provided. Also, a projection 65 is provided on the mating surface of the plate body 62.
However, a hole 66 is provided in a corresponding portion of the plate body 61, and the projection 65 and the hole 66 serve as a snap, so that the two plate bodies can be freely opened and closed. As shown in FIG. 20, the stopper 60 is sandwiched between the ridges 7 and closed, and the ridges 7 are held in an empty space, so that the stopper 60 can be easily attached to the outer frame 1, and the two-piece plate can be attached. It can be easily removed by opening it. When the inner frame 11 is closed, the lower surface of the plate body 61 of the stopper 60 comes into contact with the contact surface 24 of the inner frame 11 and the inner frame 11
Stops rotating.

[0028]

According to the present invention, when the inner frame is mounted on the outer frame, the position of the hanging base can be freely selected, and the opening and closing of the inner frame does not hinder the ceiling inspection opening which can be mounted in any direction. Thus, the stopper can be easily mounted. The stopper also has the effect of pressing the inner frame from both sides to prevent rattling, so that the inner frame can be opened and closed smoothly.

[Brief description of the drawings]

FIG. 1 is a top view of a ceiling inspection port according to an embodiment.

FIG. 2 is a perspective view of the outer frame 1. FIG.

FIG. 3 is a partial cross-sectional view near the end of the outer frame 1;

FIG. 4 is a perspective view of the inner frame 11;

FIG. 5 is a partial side view of the vicinity of an end of the inner frame 11;

FIG. 6 is a perspective view showing a state where the inner frame 11 is attached to the outer frame 1;

FIG. 7 is an explanatory diagram of attachment of an inner frame.

FIG. 8 is a sectional view taken along line AA in FIG.

FIG. 9 is a perspective view of a corner member 3;

FIG. 10 is a sectional view taken along the line BB in FIG. 1;

11 is a perspective view of the stopper 30. FIG.

FIG. 12 is an explanatory diagram of attachment / detachment of a stopper 30;

13 is a front view of the stopper 40. FIG.

FIG. 14 is an explanatory diagram of attachment / detachment of a stopper 40;

15 is a top view, a left side view, and a front view of the stopper 50. FIG.

16 is a sectional view taken along line DD in FIG.

FIG. 17 is an explanatory view of attachment / detachment of the stopper 50;

18 is a front view of the stopper 55. FIG.

FIG. 19 is a perspective view of a state where a stopper 60 is opened.

FIG. 20 is a cross-sectional view of the mounted state of the stopper 60.

FIG. 21 is a top view of an outer frame 40 of a conventional ceiling inspection port.

FIG. 22 is a side view of an inner frame 41 of a conventional ceiling inspection opening.

FIG. 23 is an explanatory view of mounting a conventional inner frame of a ceiling inspection port.

FIG. 24 is an explanatory view of attaching a conventional ceiling inspection port inner frame.

FIG. 25 is an explanatory cross-sectional view of a shaft support portion of a conventional ceiling inspection port.

FIG. 26 is an explanatory sectional view of a conventional stopper portion of a ceiling inspection port.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Outer frame 2 Mold material 3 Corner material 4 Vertical plate part 5 Horizontal plate part 6 C-shaped groove 7 Ridge 7a Tip part 8 Ridge 8a Tip part 9 Hook groove 10 Bearing groove 10a Inlet 11 Inner frame 12 Mold member 13 Vertical plate part 14 Horizontal plate part 15 C-shaped groove 16 Ridge 17 Corner material 18 Shaft pin 19 Through hole 20 Reinforcement boss part 21 Flange part 22 Coil spring 23 Latch 24 Contact surface 30 Stopper 31 Main plate part 32 Projection part 33 Flexible part 40 Stopper 41 Main plate portion 42 Projection portion 43 Projection portion 44 Projection portion 45 Arc of diameter w 46 Arc of diameter W 50 Stopper 51 Main plate portion 52 Projection portion 53 Overhanging portion 55 Stopper 56 Main plate portion 57 Elastic projection 58 Notch 60 Stopper 61 Plate body 62 Plate Body 63 Notch 64 Notch 65 Projection 66 Hole 70 Outer frame 71 Inner frame 72 Shaft pin 73 Bearing groove 74 Stopper

Claims (6)

[Claims] 1. An outer frame having a square outer frame and an inner frame, wherein the outer sides of two opposing sides of the inner frame are pivotally supported inside the two opposing sides of the outer frame. On the other hand, a plastic stopper having a protruding portion projecting inward is detachably mounted inside the outer frame at the ceiling inspection port which can be opened and closed by rotating about the pivot portion as an axis. An upward contact surface is formed on the outside of the outer frame, and when the inner frame is rotated with respect to the outer frame and closed, the corresponding contact surface abuts on the protrusion of the stopper to stop the rotation. Characteristic ceiling inspection door 2. The ceiling inspection door according to claim 1, wherein the outer frame is formed with a bearing groove having an inlet on the inside near both ends on the inside of each side, and the inner frame is opposed to the opposite frame.
A shaft pin is formed protruding near the end of the side, and the inner frame can be opened and closed in any direction by inserting the shaft pin into the bearing groove on any side of the outer frame and supporting it. Ceiling inspection door 3. The ceiling inspection door according to claim 1, wherein
The ceiling inspection opening, wherein the bearing groove is formed to be inclined downward from the entrance toward the end. 4. The ceiling inspection door according to claim 1, wherein the outer frame has a C-shaped groove formed therein, the cross-sectional shape of which opens inward and has a C-shaped cross section. Wherein the stopper comprises a main plate portion fitted into the C-shaped groove, and a projecting portion projecting inward from the main plate portion,
A ceiling inspection port, wherein a horizontal flexible portion is formed in the main plate portion, and the flexible portion is bent into two upper and lower portions by the flexible portion. 5. The ceiling inspection door according to claim 1, wherein the outer frame is formed with a C-shaped groove formed in the inside of the outer frame, the cross-section opening inwardly having a C-shape. Wherein the stopper comprises a main plate portion fitted into the C-shaped groove, and a projecting portion projecting inward from the main plate portion,
Assuming that the opening width of the C-shaped groove is w and the groove width is W, the height of the main plate portion is substantially the same as or slightly smaller than the groove width W, and the lateral width is substantially the same as or slightly smaller than the opening width w. Are cut out so as not to protrude outside the arc of diameter W. The main plate is placed in a C-shaped groove with the main plate lying sideways and rotated 90 degrees in a predetermined direction to stop the stopper. Ceiling inspection door characterized in that the ceiling is installed in a C-shaped groove 6. The ceiling inspection port according to claim 1, wherein the outer frame has a ridge protruding inward on an inner side thereof, and the stopper is hinged. The two pieces of the plate are opened and closed so that when the two pieces are closed, a void having a shape corresponding to the shape of the ridge is formed between the two pieces of the plate. A notch portion is formed, and the stopper is attached to the outer frame by closing the stopper with the ridge sandwiched therein and holding the ridge in the space.