JP2571087Y2 - Ceiling mounted detector - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ceiling-mounted detector embedded in a ceiling of a building such as an office, a hotel, a hospital, and the like.

[0002]

2. Description of the Related Art Conventionally, in buildings and the like,
Various detectors such as temperature and humidity detectors, infrared detectors, and fire detectors are embedded and installed in the ceiling and wall to control air conditioning and prevent theft and fire. FIG. 9 shows a conventional example of a mounting structure of a sensor for monitoring abnormalities such as gas leaks and fires in the room and above the ceiling, where 1 is a room, 2 is a ceiling plate, 3 is a ceiling, and 4 is a room of the ceiling plate 2. A fire detector installed on the side to detect a fire in the room 1, 5 is a gas leak or fire detector for detecting gas leaks and fires from the ceiling 3, and 6 is an alarm based on detection signals of the sensors 4 and 5. It is an alarm device.
As described above, conventionally, a gas leak or a fire detector 5 for detecting an abnormality such as a gas leak from the ceiling 2 and a fire is installed on the ceiling 3 independently of the indoor fire detector 4.

[0003] As a mounting structure of a sensor, a method of fixing a case accommodating a sensor by a fastening means such as a screw is the most common (eg, Japanese Utility Model Publication No. 4-54550). As another method, for example, Japanese Utility Model 3-425
A mounting device disclosed in Japanese Patent Publication No. 44-44 is also known.
In this mounting device, a mounting bracket bent in a U-shape is mounted on a back side of a case body by a set screw so as to be able to undulate, and the mounting bracket and a flange provided on a front surface of the case main body are combined with a ceiling plate or the like. The case body is fixed by sandwiching the mounting surface of the case.

As a case for storing the sensor, a single type (Japanese Utility Model Publication No. 3-42444) and a split type (Japanese Utility Model Application Publication No.
No. 54550). Among them, the split type includes a first case fixed to a ceiling or the like, and a second case fixed to the first case. An external terminal to which an external cord is connected is provided in a case, and a sensor and an internal terminal are provided in a second case,
The second case is incorporated in the first case to connect the internal terminals and the external terminals. In the case of the detector having the case divided into two parts as described above, even when the detector is to be mounted before the indoor work is completed due to the construction period, the first case is required. Since the second case can be incorporated into the first case after the indoor work is completed only by attaching only the second case, there is no fear that the sensor is damaged, and the second case is used for inspection and replacement of the sensor. By simply removing the first case from the first case, the first case does not need to be removed from a wall or the like, and has an advantage of excellent workability.

[0005]

Conventionally, as shown in FIG. 9, a fire detector 4 exclusively used for a room and a gas leak or fire detector 5 exclusively used for a space above the ceiling are separately provided. There has been a problem in that the number of devices has increased, and especially in the backside of the ceiling, installation of the sensor 5, wiring work, maintenance and the like are troublesome. Further, an alarm device having a large number of monitoring points must be used as the alarm device 6, which causes a problem that the cost is increased. Another problem is that, in the conventional device in which the case is formed in two parts, the surroundings of the external terminals are not dustproof, so that when installed on a ceiling, dust and the like are liable to adhere, and the external terminals and the internal terminals are not connected to each other. There is a problem that the reliability of the contact is reduced.

Accordingly, the present invention has been made in view of the above-mentioned conventional problems, and an object of the present invention is to be able to monitor the state of the room and the inside of the ceiling with a single detector. An object of the present invention is to provide a ceiling-mounted detector capable of favorably protecting external terminals from dust and the like.

[0007]

In order to achieve the above object, the present invention provides an external case which has an external terminal to which an external cord is connected on the back and which is embedded and installed in a ceiling, a sensor, a wiring board, and an internal terminal. Etc., an inner case housed in the outer case and housed in the outer case, a terminal cover detachably attached to a back surface of the outer case by an engagement means to cover the external terminal, and a front opening of the inner case. A front cover, wherein the front cover is formed with a communication hole through which room air flows into the inner case, and a plurality of communication holes which communicate with each other to the outer case and the inner case and allow air behind the ceiling to flow into the inner case. The air holes are formed respectively, and the air holes provided in the outer case also serve as locking portions for locking the engaging means of the terminal cover.

[0008]

In the present invention, gas, smoke and the like in the room flow into the inner case through the flow hole of the front cover and are detected by the sensor. Gas, smoke, and the like behind the ceiling flow into the inner case through the ventilation holes of the outer case and the inner case, and are detected by the sensor. The terminal cover is attached to the outer case and protects the external terminals from dust and the like. The ventilation holes provided in the outer case also serve as locking portions for locking the engagement means of the terminal cover, thereby simplifying the configuration of the outer case.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail based on an embodiment shown in the drawings. FIG. 1 is a schematic diagram showing an embodiment in which the present invention is applied to a ceiling-mounted fire detector, FIG. 2 is a sectional view of the detector, FIG. 3 is an exploded perspective view of the detector, and FIG. FIG. 5 is a rear view of the outer case, FIG. 6 is an enlarged sectional view taken along the line VI-VI of FIG. 5, FIG. 7 is a perspective view of the contact spring and the internal terminal, and FIG. 8 is a rear view of the inner case. is there. In this embodiment, one fire detector 10 is embedded in a ceiling plate 2 and installed to detect a fire in a room 1 and a ceiling 3 in FIG. Below, fire detector 1
0 and the like will be described in detail with reference to FIGS.

Referring to FIG. 2 and FIG.
Is an outer case 11 and an inner case 12 having a double cylinder structure formed into two parts, a terminal cover 13 detachably attached to the back surface of the outer case 11, and a detachable front surface of the outer case 11 and the inner case 12. Has a front cover 14 and the like that are attached to the front panel.

The outer case 11 is integrally formed by injection molding of a resin. The outer case 11 has an outer diameter smaller than a hole diameter of a mounting hole 15 provided in the ceiling plate 2 and has a cylindrical body with an open front surface. 11A and a flange portion 11B protruding from the outer peripheral surface of the front end of the main body 11A and closely contacting the indoor side surface 2a of the ceiling plate 2 via a packing 16. A pair of engaging holes 17, 18 (FIG. 4) and the screw mounting hole 1
9 (FIGS. 2, 4 and 5), six long holes 20 (FIG. 4) and external terminal mounting portions 21 (FIGS. 2, 5 and 5).
6) are formed respectively, and the main body 1 is provided on the rear end side of the peripheral surface.
1A is communicated with the ceiling space 3 and is long in the axial direction, for example, 6
The two elongated ventilation holes 22 are formed equally in the circumferential direction.

In FIG. 4, the pair of engaging holes 17, 1
Numeral 8 is used to lock the inner case 12 and each other 18
The outer case 11 is formed with a phase difference of 0 ° and has a hook shape (L-shape) in plan view, so that the radial holes 17a and 18a and the radial hole 1
Circumferential holes 17b, 1 connected to the inner ends of 7a, 18a
8b.

The screw mounting hole 19 is formed in the center of the back surface of the outer case 11, and a mounting screw 46 to be described later is rotatably penetrated from the inside of the outer case 11.

The long holes 20 are formed between the engagement holes 17 and 18 at predetermined intervals in the circumferential direction by three each.

The external terminal mounting portion 21 is mainly
And a pair of mounting walls 24a and 24b which are provided in parallel at a constant interval in the circumferential direction as shown in FIG. 6, and the inner terminals of the mounting walls 24a and 24b are provided with external terminals 25. Supporting portions 27 for supporting the terminal fittings 26 are respectively provided integrally and projecting therefrom. Then, the external terminal mounting portion 21
Pass through the center of the outer case 11,
The three external terminal mounting portions 21 on the same side are provided so as to be opposed to each other with the imaginary line 29 (FIG. 5) connecting them 18 interposed therebetween.

The vent hole 22 is formed in the outer case 11 to be long in the axial direction on the peripheral surface of the rear end portion, and the rear side wall wall forms the locking portion 41 of the terminal cover 13.

In FIG. 6, the external terminal 25 is composed of the terminal fitting 26 and a contact spring 30, and one end of an external cord 31 is connected to the terminal fitting 26 by a screw 32. The terminal fitting 26 is formed by appropriately bending a metal plate having a thickness, width and length by press working, so that a central portion 26A of a “H” shape in a side view having two substantially perpendicular slopes 33a and 33b is formed. And the central part 26A
And a narrow base 26C, 26D integrally extended to the other end of the central part 26A and the end opposite to the central part of the horizontal base 26B. A storage space A is provided between the pair of mounting walls 24a and 24b, and the contact space 30 is provided together with the pair of mounting walls 24a and 24b by being disposed between the pair of mounting walls 24a and 24b. Is formed. Central part 2
The screw 32 is screwed into the outer slope 33b of 6A,
One end of the external cord 31 is connected to form a connection part of the external cord 31. The narrow portions 26C, 26D provided at both ends of the terminal fitting 26 are respectively inserted and locked from behind into locking holes 34, 35 provided in the outer case 11, thereby attaching the terminal fitting 26 to the external terminals. It is fixed to the part 21. The other end of the external cord 31 is connected to the alarm device 6 (FIG. 1).

In FIG. 6 and FIG.
Reference numeral 0 denotes a plate-like base 30a, an elastically deforming portion 30b bent substantially at a right angle forward from one end of the base 30a by forming a thin plate spring into a shape as shown in the drawing by bending. The base 3 from the end opposite to the base of the deformed portion 30b
0a, a bent portion 30c bent at a substantially right angle to the opposite side,
A U-shaped terminal receiving portion 30d provided on the front side of the bent portion 30c so as to surround three sides, and a holding portion 3 provided in the terminal receiving portion 30d for elastically holding an internal terminal 38 described later.
0e, the base 30a is welded and fixed to the front surface of the horizontal base 26B of the terminal fitting 26, and the holding portions 30e are located in the storage space A and on both sides of the elongated hole 20.
The holding portion 30e is made up of a total of four resilient pieces 130, each of which is a pair of one set formed by inwardly bending the front end of two opposing sides of the terminal receiving portion 30d. Four points are held. When the narrow portions 26C and 26D of the terminal fitting 26 are inserted and locked in the locking holes 34 and 35 of the outer case 11, respectively, the base 30a of the contact spring 30 formed as described above is inserted into the outer case. 11 is closely fixed to a receiving stand 37 protruding from the back surface,
Elastic deformation part 30b, bent part 30c, and terminal receiving part 30
d is the back surface of the outer case 11 and the pair of mounting walls 24
a and 24b so that they can swing freely. If the distal end side of the base 30a of the contact spring 30 is made swingable in this way, manufacturing errors of the outer case 11 and the inner case 12 can be reduced.
Even when the relative displacement between the contact spring 30 and the internal terminal 38 is large, when the contact spring 30 is connected to the internal terminal 38, the elastically deforming portion 30b is elastically deformed in the direction of the arrow in FIG. Because of the movement, the error, the displacement, and the like can be effectively absorbed, and each elastic piece 130 can be brought into contact with the internal terminal 38 with substantially the same contact pressure.

In FIG. 2 and FIG. 3, the terminal cover 13 is formed in a cylindrical shape having substantially the same outer diameter as the outer case 11 and having an open front surface. Engaging claws (engaging means) 40 are integrally protruded, and these engaging claws 40 are locking members which are rear walls of the vent holes 22 formed at the rear end of the outer peripheral surface of the outer case 11. Part 4
1 is engaged. That is, the ventilation hole 22 is also used as a locking portion for locking the terminal cover 13 to the outer case 11. The positioning of the terminal cover 13 in the rotation direction with respect to the outer case 11 is not required to be strict. Therefore, any two of the six ventilation holes 22 which are opposed to each other by 180 ° are used for locking the terminal cover 13. By attaching the terminal cover 13 and the external cord 3
1 is easy to route.

The terminal cover 13 has a pair of external cord lead-out holes 42 formed therein. The external code lead-out hole 42 has a round hole 42 formed on the back surface of the terminal cover 13.
and a slit portion 42b formed on the peripheral surface over the entire length in the axial direction and having one end connected to the round hole 42a and the other end opened to the front opening of the terminal cover 13. In this case, if the external code lead-out hole is simply constituted by the round hole portion 42a, it is necessary to connect the external cord 31 to the terminal fitting 26 of the external terminal 25 in advance through the round hole.
When the external cord lead-out hole 42 is formed in a long hole shape and one end is opened to the front opening of the terminal cover 13 as in the present invention, the external cord 31 is inserted into the terminal cover 13 from the slit portion 42b. The terminal cover 13 can be attached to the outer case 11 even after the external cord 31 is connected to the external terminal 25 because it can be led out from the round hole 42a. Therefore, there is no need to pass the external code 31 through the external code lead-out hole 42 in advance, so that forgetting to pass the external code 31 does not occur.

Further, a pair of guide holes 43a, 43b and inclined portions 44a, 44b are formed at the rear end of the outer peripheral surface of the terminal cover 13 with a phase difference of 180 °. The guide hole 43a and the inclined portion 44a and the guide hole 43b and the inclined portion 44b are formed at the same position. At the center of the inside of the terminal cover 13, a cylindrical portion 47 through which the mounting screw 46 is rotatably penetrated is integrally provided.

As shown in FIGS. 2, 3 and 8, the inner case 12 has a cylindrical main body 12A having an open front face to be inserted into the main body 11A of the outer case 11, and a main body 12A.
And a flange portion 12B integrally projecting from the outer peripheral surface of the front end of the outer case 11. When the main body 12A is correctly inserted into the outer case 11, the back surface of the flange portion 12B comes into close contact with the front surface of the flange portion 11B of the outer case 11. It is configured to:

On the back surface of the inner case 12, the internal terminal 38 is provided so as to penetrate therethrough, and a pair of engaging portions 50,
51 are integrally provided. Six internal terminals 38 are provided concentrically so as to correspond to the external terminals 25 of the outer case 11, and are formed by insert molding.
2 and are formed integrally. The engaging portions 50 and 51 are provided so as to correspond to the engaging holes 17 and 18 (FIG. 4) of the outer case 11, and are formed in an inverted L-shape in a side view as shown in FIG. Thus, the bases 50a, 51a extending rearward of the inner case 12 and the bases 50a, 51
A bent portion 50b, 51b extending radially outward of the inner case 12 is provided at the end of the inner case 12, and when the inner case 12 is inserted into the outer case 11, the engagement holes 17, 18 are formed in the radial direction. When the inner case 12 is rotated clockwise in FIG. 4 in this state, the bases 50a and 51a are inserted into the holes 17a and 18a, respectively, as indicated by two-dot chain lines in FIG.
b, 18b, and the bent portions 50b, 51b abut and engage with the back surface of the outer case 11, and the inner case 12 is
It is detachably fixed to.

However, the inner case 12 is rotated 180 degrees around the center axis.
When rotated and inserted into the outer case 11, different external terminals 25 and internal terminals 38 are connected to break the electric circuit or malfunction as a detector. The direction holes 17a, 18a and the engaging portions 50,
The shape of the radial hole 18a and the bent portion 51b of the engaging portion 51 are formed into similar trapezoids in which the shapes of the radial holes 17a and the bent portion 50b of the engaging portion 50 can be fitted to each other. Are formed in similar rectangular shapes that can be fitted to each other, so that the bent portion 50b of the engaging portion 50 does not fit to the radial hole 18a.

Further, each of the internal terminals 38 is formed such that the bent portions 50b, 51b of the engaging portions 50, 51 have radial holes 17a, 18a of the engaging holes 17, 18, as shown by a two-dot chain line in FIG.
Respectively, is inserted from the inside of the outer case 11 into the corresponding long hole 20 and protrudes to the rear of the outer case 11, and by rotating the inner case 7 clockwise, the protruding portion is as shown in FIG. The holding part 3 of the contact spring 30
The external terminal 25 and the internal terminal 38 are electrically and mechanically connected with each other by being inserted between the terminals 0e. Therefore, the operation of attaching the inner case 12 to the outer case 11 and the operation of electrically and mechanically connecting the external terminal 25 and the internal terminal 38 are performed simultaneously with one touch.

At the rear end of the peripheral surface of the inner case 12, there are formed six axially long ventilation holes 52 which are arranged in the circumferential direction and communicate the inner case 12 with the ceiling back 3. The ventilation holes 52 are formed corresponding to the ventilation holes 22 of the outer case 11, and the inner case 12 is inserted into the outer case 11,
When locked by the engagement of the engagement holes 17 and 18 with the engagement portions 50 and 51, as shown in FIG. 2, it overlaps and communicates with the ventilation hole 22, and communicates the inside of the inner case 12 with the ceiling back 3. Let it.

Further, a wiring board 54 is housed inside the inner case 12. The wiring board 54 is composed of two wiring boards 54A and 54B which are disposed apart from each other in the front and rear directions.
8 is screwed and fixed to the inner end face by a set screw 55. Therefore, a screw hole into which the set screw 55 is screwed is formed on the inner end surface of the internal terminal 38. on the other hand,
A screw mounting hole (not shown) through which the set screw 55 is inserted is formed in the wiring board 54A, and a land portion (not shown) of a printed wiring pattern is formed around the opening of the screw mounting hole. Have been. Therefore, the wiring board 54
A is closely fixed to the inner end surface of the internal terminal 38 with the set screw 55, and the wiring board 54A and the internal terminal 38 are
5 and the land are electrically connected, thereby eliminating the need for connection by a lead wire. Note that a pair of positioning recesses (not shown) are formed on the peripheral edge of the wiring board 54A, and these recesses are fitted to screw mounting portions 56 protruding from the inner peripheral surface of the inner case 12. In addition, the wiring board 54 is positioned in the rotation direction, and erroneous connection with the internal terminal 38 is prevented.
On the other hand, the front wiring board 54B is fixed to the front surface of the screw mounting portion 56 by a set screw 58, and is electrically connected to the rear wiring board 54A by a lead wire 59. A sensor 60 for detecting smoke is provided in the center of the front surface of the wiring board 54B.

The front cover 14 is formed in the shape of a shallow dish, and is provided with a disk portion 14A that covers the front surfaces of the outer case 11 and the inner case 12, and protrudes from the outer periphery of the surface of the disk portion 14A. A plurality of flow holes 62 are formed in the center of the disk portion 14A, and the cylindrical portion 14B is fitted to the outer peripheral surface of the flange portion 11B of the outer case 11. Further, for example, four engagement claws 63 (FIGS. 3 and 8) and a pair of positioning projections 64 are integrally provided near the outer periphery of the inner surface of the disk portion 14A. Engaging claw 6
3 engages with the outer peripheral portion of the back surface of the flange portion 12B of the inner case 12, thereby detachably locking the front cover 14 to the inner case 12. The positioning projection 64 engages with a cutout recess 65 formed on the outer peripheral surface of the flange portion 12 </ b> B of the inner case 12 to position the front cover 14 with respect to the inner case 12.

2 and 3, on the outer periphery of the terminal cover 13, a mounting bracket 70 for locking and fixing the outer case 11 to the ceiling plate 2 is provided. This mounting bracket 70 is composed of a highly rigid metal plate 72 having a screw hole 71 at the center of which the mounting screw 46 is screwed, and a leaf spring 73 fixed to the front surface of the metal plate 72. The leaf spring 73 is bent in a substantially U-shape to form a pair of left and right opening and closing legs 73a and 73b extending in the front-rear direction, and a connecting portion 73c for connecting the rear ends of the opening and closing legs 73a and 73b.
The connecting portion 73c is locked to the metal plate 72, and the opening / closing legs 73a and 73b are slidably inserted from the rear into the guide holes 43a and 43b provided at the rear end of the outer peripheral surface of the terminal cover 13. It has been inserted. Opening and closing legs 7
3a and 73b each have a bent portion 74 bent in a V-shape inward at the center portion in the longitudinal direction, and when the mounting bracket 70 is moved back and forth by the mounting screw 46, the bent portion 74 The inclined portions 44a and 44b formed at the rear end of the outer peripheral surface are brought into contact with and separated from each other, whereby the legs are opened or closed. That is, assuming that the leaf spring 73 has a leg closing behavior,
When the leaf spring 73 is moved to the distal end side of the mounting screw 46, the bent portion 74 is located behind the terminal cover 13 as shown by a two-dot chain line in FIG.
73b keeps the closed state. The interval between the bent portions 74 in this closed leg state is smaller than the outer diameter of the terminal cover 13,
The front halves of the opening / closing legs 73a and 73b are in close contact with the outer peripheral surface of the terminal cover 13, so that the outer case 11 can be extracted from the mounting holes 15 of the ceiling plate 2. Now, when the mounting bracket 70 is located at the tip end side of the mounting screw 46 as shown by the two-dot chain line and the mounting screw 46 is rotated to move the mounting bracket 70 forward, the leaf spring 73
Of the bent portion 74 of the terminal cover 13 are inclined.
Opening and closing legs 73a, 73b
Is gradually opened. When the mounting bracket 70 moves forward by a predetermined distance, the front end of the leaf spring 73 contacts the back surface 2b of the ceiling plate 2 and presses the flange portion 11B of the outer case 11 against the back surface 2b of the ceiling plate 2. Therefore, the flange 11 </ b> B of the outer case 11 and the leaf spring 73 sandwich the ceiling plate 2, thereby fixing the outer case 11 to the ceiling plate 2. To remove the outer case 11, the mounting bracket 46 may be rotated in the opposite direction to move the mounting bracket 70 backward. Then, the bent portion 74 of the leaf spring 73
Moves to the rear of the terminal cover 13, and the open / close legs 73a, 73
outer case 1 because b closes due to her own closing behavior
1 can be easily removed from the mounting hole 15 of the ceiling plate 2.

The operation of attaching the outer case 11 to the ceiling plate 2 is performed before the inner case 12 is attached. The number of leaf springs 73 is not limited to one, and a plurality of leaf springs 73 can be used. For example, when two leaf springs 73 are used, the leaf springs 73 may be attached to the metal plate 72 so as to be orthogonal to each other and shifted by 90 °.

Here, in the present embodiment, a case where a spring having a leg closing habit is used as the leaf spring 73 has been described, but it is a matter of course that the leaf spring 73 may have a leg opening habit. . In that case, the inclined portions 44a, 44
b is not always necessary, and the guide holes 43a, 43
b restricts the opening angle of the open / close legs 73a, 73b when the outer case 11 is fixed, and closes the open / close legs 73a, 73b as the mounting bracket 70 moves backward.

Thus, in such a configuration, the inside of the inner case 12 is formed in the flow hole 62 formed in the front cover 14.
And the air hole 22 provided in the main body 11A of the outer case 11 and the main body 1 of the inner case 12.
Since it communicates with the ceiling 3 by the ventilation hole 52 provided in 2A, the air in the room 1 and the air in the ceiling 3 can both flow through the inner case 12. Therefore, it is possible to detect fires in the room 1 and the ceiling 3 with one fire detector 10, and it is possible to reduce the number of installed detectors. Further, since the fire detector 10 is installed on the ceiling plate 2, installation, wiring work, maintenance and the like are easy. In addition, the present invention provides an outer case 11 in which the case is attached to the ceiling plate 2 and an outer case 11 for housing and holding the sensor 60 and the like.
The inner case 12 is detachably attached to the inner case 12 so that the detector can be installed before the indoor work is completed due to the construction period. Since the inner case 12 can be incorporated into the outer case 11 after the indoor work is completed only by attaching the case 11 alone, there is no fear that the sensor 60 and the front cover 14 may be damaged. Further, according to the present invention, since the terminal cover 13 that covers the external terminal 25 is attached to the back surface of the outer case, dust and the like do not adhere to the external terminal 25, and the reliability of connection with the internal terminal 38 is improved. Further, since the engaging claw 40 provided on the inner case 12 is configured to be locked to the rear wall of the vent hole 22 of the outer case 11, that is, the engaging portion 41, the vent hole 22 is engaged with the terminal cover 13. There is no need to provide a dedicated locking portion on the outer case 11 which also serves as a stopping portion,
The die for the outer case 11 is easily manufactured.

Although the above embodiment has been described with reference to the case where the present invention is applied to the fire detector 10, the present invention is not limited to this. The present invention is also applicable to a gas leak detector. It is also possible to make it a composite type sensor for detecting the pressure.

[0034]

As described above, in the ceiling-mounted detector according to the present invention, the terminal cover is provided on the back of the outer case to cover the external terminals, so that the external terminals can be protected from dust and the like, and the interior can be protected from dust. The reliability of connection with the terminal can be improved. Also, in the present invention, the front cover is formed with a communication hole for communicating between the room and the inside of the inner case, and the outer case and the inner case are formed with a ventilation hole for connecting the inside of the ceiling and the inside of the inner case. The indoor air and the air above the ceiling can be circulated, so that the state of the room and the inside of the ceiling can be monitored with one detector, and it is particularly suitable for application to smoke and gas leak detectors. . Furthermore, in the present invention, the locking portion for locking the engagement means of the terminal cover is also used in the ventilation hole provided in the outer case, so that it is not necessary to separately provide the locking portion in the outer case, and The mold can be easily manufactured, and the cost can be reduced. Furthermore, since the case is divided into two parts, an outer case and an inner case, even when the installation work requires the detector to be installed before the indoor work is completed due to the construction period, the outer case is required. After the indoor work has been completed, the inner case can be assembled into the outer case by simply attaching only the outer case.Also, for maintenance, inspection and replacement of the sensor, the outer case does not need to be removed, and the external cord and external terminal are connected. Since it can be left as it is, its practical effect is great, such as excellent workability.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing an embodiment in which the present invention is applied to a ceiling-mounted fire detector.

FIG. 2 is a sectional view of the sensor.

FIG. 3 is an exploded perspective view of the sensor.

FIG. 4 is a front view of the outer case.

FIG. 5 is a rear view of the outer case.

FIG. 6 is an enlarged sectional view taken along line VI-VI of FIG. 5;

FIG. 7 is a perspective view of a contact spring and internal terminals.

FIG. 8 is a rear view of the inner case.

FIG. 9 is a schematic configuration diagram showing an arrangement of a conventional sensor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Room 2 Ceiling board 3 Above the ceiling 10 Fire detector 11 Outer case 12 Inner case 13 Terminal cover 14 Front cover 22 Vent hole 25 External terminal 38 Internal terminal 40 Engagement claw 41 Engagement part 52 Vent hole 54 Wiring board 60 Smoke sensor 62 Distribution hole

Claims (1)

(57) [Scope of request for utility model registration] 1. An outer case having an external terminal connected to an external cord on the back and embedded in a ceiling, and an inner case containing a sensor, a wiring board, an internal terminal and the like and housed and arranged in the outer case. A case, a terminal cover detachably attached to the rear surface of the outer case by engaging means to cover the external terminals, and a front cover covering the front opening of the inner case. Forming a circulation hole that circulates in the case, forming a plurality of ventilation holes that communicate with each other to the outer case and the inner case and allow air behind the ceiling to circulate in the inner case, and provided in the outer case. The ceiling vent-mounted detector, wherein the vent hole serves also as a locking portion for locking the engagement means of the terminal cover.