JP7685334B2 - smoke detector - Google Patents

Description

The present invention relates to fire detectors, and in particular to technology that is effective when applied to fire detectors (smoke detectors) that use a photoelectric smoke sensor consisting of a light-emitting element and a light-receiving element.

Conventionally, as a fire detector, there is known a smoke detector that uses a photoelectric smoke sensor in which light emitted from a light-emitting element is scattered by smoke particles and the scattered light is received by a light-receiving element to detect smoke.
Some photoelectric smoke sensors for smoke detectors are configured so that a light-emitting element and a light-receiving element are housed in a dark box with a labyrinth-structured light-shielding wall surrounding it to prevent light from entering from the outside, with their optical axes offset from each other.When smoke flows into the dark box in the event of a fire, the light emitted from the light-emitting element is scattered by smoke particles, and when the scattered light is detected by the light-receiving element, it is determined that a fire has occurred and an alarm is sounded.

Generally, fire detectors have a white base surface color for their housings (casings) to match the white color often used as the environmental color in the areas where they are installed, so that they do not stand out when an alarm is not being triggered, since the ceilings of many fire-prevention facilities are generally white. On the other hand, the operation indicator light that lights up or flashes when a fire is detected must be highly visible when it is lit, for example when installed on the ceiling. For this reason, a window is provided in part of the detector body (casing), and the spot-shaped light emission of the operation indicator light can be seen through the window (see, for example, Patent Document 1). Some smoke detectors also have multiple operation indicator lights to improve visibility from all 360° directions (see, for example, Patent Document 2).

JP 2001-126165 A JP 2013-8084 A

Since the ceiling surface on which a fire detector is installed is often white or a white-based color, a fire detector with a white base color that matches the installation environment can be installed to make the fire detector less noticeable. If the fire detector is a heat detector, it is only necessary to detect the conduction of heat, so it is possible to form the detector without providing any detection opening at all, depending on the detection element used. However, for smoke detectors using photoelectric smoke sensors, it is essential to take in the smoke particles to be detected in order to detect smoke, so a relatively large smoke inlet that does not obstruct the inflow of smoke is provided in the outer cover, and an insect screen is arranged nearby to surround the smoke sensor. Since the insect screen of a conventional smoke detector is dark in color, even if the smoke detector body is made white to match the color of the environment to make the smoke detector less noticeable, the dark-colored insect screen stands out through the smoke inlet, and there is a problem that the smoke detector as a whole does not harmonize with the surrounding colors. Furthermore, smoke detectors are configured with a dark box that houses the smoke sensor, but because the dark box is made of black resin due to its characteristics, part of it can be seen through insect screens, so there is an issue that even if a fire detector with a white base that matches the installation environment is installed, the dark color of the dark box that can be seen through the insect screen stands out.

Furthermore, when an operation indicator light is provided, as in the smoke detector of Patent Document 2, the operation indicator light is formed from a transparent or translucent material to guide the light. However, this results in a configuration in which an operation indicator light of a different color is exposed on the surface of the detector case (outer cover), which is based on a white color that matches the installation environment. This creates the problem that when the light is off, the surface of the operation indicator light does not blend in with the color of the detector case (white that matches the installation environment), making the operation indicator light stand out.

The present invention has been made in response to the above-mentioned problems, and its purpose is to provide a smoke detector that uses a photoelectric smoke sensor such that the operation indicator light has good visibility when it is activated (lit) and is inconspicuous when it is not activated (not lit).
Another object of the present invention is to provide a smoke detector that prevents components such as the insect screen, dark box, and dark box base from becoming conspicuous, allowing the detector to blend in with the installation environment.

In order to achieve the above object, the present invention provides
A smoke detector that includes a housing made of a main body and a cover member covering the upper side of the main body, a detection unit equipped with a photoelectric smoke sensor, and a circuit board equipped with an electronic circuit that detects the occurrence of a fire based on a signal from the detection unit, and that is equipped with an insect screen that is visible from the outside,
The cover member is provided with a cover body having an opening facing the sensing unit, a head portion covering the sensing unit, and a plurality of pillars connecting the head portion and the cover body, and a smoke inlet is formed between each of the plurality of pillars;
The smoke detector has a light emitting portion constituting an operation indicator light , and the light emitting portion is disposed on a surface of the cover member at a position that can be seen from directly below when the smoke detector is installed on a ceiling surface ,
A light-transmitting coating layer having a color similar to the surface color of the cover member is provided so as to cover the light emitting portion.

In the smoke detector having the above-mentioned configuration, a coating layer of a similar color to the surface color of the cover member is provided to cover the light emitting portion constituting the operation indicator light, so that the operation indicator light blends in with the color of the installation environment and is not conspicuous when it is not lit. Also, since the coating layer covering the light emitting portion allows light to leak out, the lit state of the operation indicator light can be visually confirmed when it is lit.
Here, the operation indicator light has an annular shape and is disposed near the opening of the cover member and at an outer position of the pillar.
This gives the light emitting portion an annular shape, so that the operation indicator lamp can be easily seen from all directions when it is lit.

The covering layer is formed of a coating film formed on the exposed surface of the light emitting portion.
According to this configuration, it is only necessary to form a coating on the exposed surface of the light emitting portion. The coating can be easily formed, for example by applying paint, so that the sensor blends in with the color of the installation environment and is not conspicuous when the operation indicator light is not lit.

Alternatively, the light emitting member is disposed inside the cover member,
The covering layer is formed on a portion of the cover member facing the light emitting portion.
With this configuration, it is only necessary to form a coating layer on the portion of the cover member opposite the light emitting portion, so that the sensor can easily blend in with the color of the installation environment and be made inconspicuous when the operation indicator light is not lit.

Furthermore, it is preferable that the portion is a thin-walled portion and is formed in a portion excluding at least the vicinity of the plurality of columns.
With this configuration, the thickness of the cover material is greater in the vicinity of the pillar connecting the head portion and the cover main body portion, thereby preventing a decrease in the strength of the base of the pillar and making it less likely for deformation to occur even if an external force is applied to the head portion.

Also, preferably, the insect screen is housed inside the housing and is disposed so as to face the smoke inlet and surround the sensor unit,
The insect screen has a layer formed on its outer surface in a color similar to the surface color of the cover member.
With this configuration, the surface of the insect screen and the surface of the surrounding cover member are of the same color, which prevents the insect screen itself from standing out and allows the sensor to blend in with the installation environment.

Also, preferably, the sensing unit includes a dark box incorporating the photoelectric smoke sensor and a dark box base for holding the dark box, the dark box having an internal storage space for storing the photoelectric smoke sensor and a light-shielding wall having a labyrinth structure provided on the outside of the storage space,
At least the portion of the light shielding wall that comes into contact with the insect screen is colored in a similar color to the surface color of the cover member.
With this configuration, the portion of the light-shielding wall on the inside of the insect screen that comes into contact with the insect screen is the same color as the surface of the cover member, so that the color of the light-shielding wall on the inside of the insect screen can be seen through, preventing the dark box from becoming noticeable.

Furthermore, it is preferable that the dark box base is provided with a rib onto which the opening of the cover member can be fitted, and that the upper surface of the rib and a portion of the inner circumferential surface of the rib facing the dark box are colored in a similar color to the surface color of the cover member.
With this configuration, the upper and inner surfaces of the ribs of the dark box base into which the opening of the cover member fits are the same color as the surface of the surrounding cover member, thereby preventing the dark box base from becoming conspicuous.

Furthermore, it is preferable to provide a space or a light-transmitting member between the light emitting portion and the insect screen to serve as a light projection path.
According to this configuration, the light emitted from the light emitting portion is irradiated onto the surface of the insect screen, so that the outer peripheral surface of the insect screen can be used to indicate operation.

According to the present invention, in a smoke detector using a photoelectric smoke sensor, visibility is good when the operation indicator light is on, and it is possible to make it inconspicuous when the operation indicator light is off. In addition, it is possible to prevent components such as an insect screen, a dark box, and a dark box base from being conspicuous, and it is possible to make the smoke detector blend in with the installation environment.
In addition, the visible parts of the smoke detector can be unified in similar colors, making it possible to create an inconspicuous smoke detector with a color scheme that matches the required installation environment.

1 is an exploded perspective view showing an embodiment of a smoke detector including a photoelectric smoke sensor according to the present invention; 1 is a central cross-sectional view showing an internal configuration of a smoke detector according to an embodiment. 2 is a perspective view of an outer cover constituting the smoke detector of the embodiment shown in FIG. 1, viewed obliquely from above in an upside-down state. FIG. 4 is an enlarged cross-sectional view of a main part showing details of a joint between a detector body and a body cover that constitute a smoke detector of an embodiment. FIG. 10 is a central cross-sectional view showing the internal configuration of a second embodiment of a smoke detector according to the present invention; FIG. (A) is an enlarged cross-sectional view of the locking claw formation portion of the outer cover of the second embodiment of the smoke detector, (B) is an enlarged cross-sectional view of the pillar formation portion of the outer cover, and (C) is an enlarged cross-sectional view of the inner rib formation portion of the outer cover other than (A) and (B). 1 is a perspective view showing an example of an indication form by a light emitting portion of an outer cover of a smoke detector; FIG. 11 is a central cross-sectional view showing the internal configuration of another embodiment of a smoke detector according to the present invention. FIG.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of a smoke detector to which the present invention is applied will be described with reference to the drawings.
The smoke detector 10 of this embodiment is a detector capable of detecting smoke generated by a fire, and is configured to be installed on the ceiling surface of a building for use. In the following description, unless otherwise specified, the side that faces up when the smoke detector 10 is installed on the ceiling surface of a building is referred to as the lower side, and the side that faces down is referred to as the upper side.

As shown in Figure 1, the smoke detector 10 of this embodiment comprises a cylindrical main body case 11 (corresponding to the main body in the claims) having a storage recess 11A for accommodating the sensing unit and for mounting on the ceiling surface of a building, and an outer cover 12 having an opening which serves as an inlet for smoke and covering the entire upper side of the main body case 11, with the main body case 11 and outer cover 12 forming a housing having an internal storage space.
The main body case (main body) 11 is not limited to the structure shown in FIG. 1, but may have any structure capable of housing components and parts that constitute a smoke detection function.
The smoke detector 10 also comprises a circuit board 13 that is accommodated and fixed within the accommodating recess 11A of the main case 11, a dark box base 14 that has a labyrinth-structured light-shielding wall and is mounted on the circuit board 13, a cylindrical insect screen 15 that engages with and is placed on the inside of the edge of the dark box base 14, and a dark box cover 16 that engages with the dark box base 14 across the insect screen 15 to form a dark box, and the detector is formed by storing these components within the housing and combining the main case 11 and outer cover 12.

The main case 11 constitutes the lower housing wall of the smoke detector 10, and the underside of the main case 11 is provided with three connecting fittings 17 (one of which is visible in FIG. 1) for connecting to a mounting base (not shown) that is installed on the ceiling surface in advance and fixing the smoke detector 10 to the ceiling surface. The main case 11 also has three bosses 11b (one of which is visible in FIG. 1) through which screws 18 are inserted to fix the circuit board 13 and dark box base 14 housed in the housing recess 11A. The outer peripheral wall of the main case 11 is provided with an engagement portion 11c that engages with the claw portion at the tip of the locking claw 12d (see FIG. 3) of the outer cover 12.

The dark box base 14 is provided with a storage section 14a for storing a light-emitting element 19A, such as a red-emitting LED (light-emitting diode), and a storage section 14b for storing a light-receiving element 19B, such as a photodiode. The bottom walls of the storage sections 14a and 14b are formed with small holes (not shown) through which the lead terminals 19a and 19b of the light-emitting element 19A and the light-receiving element 19B can be inserted. The tips of the lead terminals of each element protruding from the underside of the dark box base 14 penetrate the circuit board 13 and are connected by flow soldering or the like. The dark box base 14 is also provided with a rib 14e that is circular in top view and fits into the central opening 12A of the outer cover 12.

The dark box base 14 is further provided with two hooks 14c that protrude toward the circuit board 13 (downward in the figure), and the tips of these hooks 14c engage with the hook holes 13c formed in the circuit board 13, so that the dark box base 14 and the circuit board 13 are integrated. The circuit board 13 is made of a printed wiring board on whose upper and lower surfaces electronic components such as resistors, capacitors, and ICs (semiconductor integrated circuits) that constitute the electronic circuit for fire detection are mounted, and the board has three screw insertion holes 13a, and is fixed in the storage recess 11A of the main body case 11 by screws 18 that penetrate the screw holes of the connecting fittings 17 and the boss portion 11b of the bottom wall of the main body case 11 and are inserted into the screw insertion holes 13a of the circuit board 13 (see Figures 1 and 2).

The light receiving element 19B is configured to be inserted into the storage section 14b while being housed in an electromagnetic shield case 20 made of a conductive material. The dark box cover 16 is provided with light shielding walls 16a and 16b formed to surround the elements housed therein, corresponding to the storage sections 14a and 14b of the dark box base 14. The light shielding walls 16a and 16b may be provided on the dark box base 14 side.
On the other hand, the outer cover 12 has a circular opening 12A in its center through which the upper part of the dark box can protrude, and is provided with a disk-shaped head portion 21 that engages with the edge of the disk-shaped lid portion 16c of the dark box cover 16 that protrudes from the opening 12A. Between the head portion 21 and the upper wall of the main body of the outer cover 12, a plurality of openings 22 that communicate with the opening 12A are formed along the circumferential direction, and the openings 22 are configured to function as smoke inlets that allow external smoke to flow into the inside of the case.

A ring-shaped light emitting member 23 made of a transparent material such as acrylic resin is fitted to the edge of the opening 12A in the center of the outer cover 12. A pair of rod-shaped light guides 23a are attached to the light emitting member 23, and the light entrance portion (end face) of one tip (lower end) of the light guides 23a faces an operation state notification light-emitting diode (LED) (not shown) mounted on the circuit board 13. Although not shown, a number of small protrusions are formed on the outer surface of the ring-shaped light emitting member 23, and a fine hole is formed at a position corresponding to the protrusion on the inner surface of the light emitting member storage section near the opening 12A of the outer cover 12 that contacts the outer surface of the light emitting member 23. The protrusions engage with the fine holes, so that the light emitting member 23 is engaged inside the opening 12A of the outer cover 12.

Fig. 3 is an inverted perspective view of the outer cover 12 constituting the sensor of Fig. 1, seen from diagonally above. As shown in Fig. 3, an outer rib 12a is provided on the outer edge of the outer cover 12, standing upward (downward in Fig. 1), and an inner rib 12b is provided at a position slightly away from the opening end of the opening 12A of the outer cover 12, standing upward (downward in Fig. 1), and an annular recess is formed between the outer rib 12a and the inner rib 12b. Water drain holes 12c are formed at four locations at approximately 90° intervals in the outer rib 12a by cutting out a part of it.
Furthermore, two through holes 12i, through which the two light guide portions 23a provided on the ring-shaped light releasing member 23 are inserted, are formed near the opening 12A of the outer cover 12. Also, a water drain hole 12h is formed in a portion closer to the opening 12A than the inner rib 12b.

In addition, at a position approximately at the same radius as the inner rib 12b and slightly toward the center, three locking claws 12d are formed at approximately 120° intervals and have a height sufficiently higher than that of the inner rib 12b, which can engage with the engagement portions 11c (three locations) on the outer peripheral wall of the main body case 11. At the same time, notches 12e (three locations) having a width slightly wider than that of the locking claws 12d are formed at the portions of the inner rib 12b corresponding to the locking claws 12d.

On the other hand, as shown in FIG. 1, the upper part of the circumferential surface of the outer wall of the main body case 11 has three engagement portions 11c, and a ring-shaped rib 11d that protrudes outward is formed at a position slightly downward from the upper end. When the outer cover 12 is attached to the main body case 11, the engagement claws 12d of the outer cover 12 and the engagement portion 11c of the main body case 11 integrate the two, and the height of the rib 11d is set so that the lower surface of the rib 11d contacts the upper end surface of the inner rib 12b of the outer cover 12.

Next, a description will be given of the device for blending the surface side parts and visible parts of the smoke detector, which is the gist of the present invention, into the environment.
In a conventional general smoke detector, the most visually noticeable part is the outer peripheral surface of the insect screen 15 facing the opening 22, which is the smoke inlet. Other parts include the upper and inner peripheral surfaces of the fitting rib 14e of the outer cover 12 provided on the dark box base 14, the part of the labyrinth-structured light-shielding wall 14d that contacts the inner surface of the insect screen 15, and the exposed surface of the ring-shaped light-emitting member 23. Of these, the fitting rib 14e has a tapered surface formed on the inside of the upper end that slopes downward toward the center so that smoke can easily flow from the outside into the smoke inlet (opening 22) of the outer cover 12, and therefore the material color (dark color) of the tapered surface stands out when the smoke detector is viewed diagonally from below.

Therefore, in the smoke detector of this embodiment, the outer peripheral surface of the insect screen 15 is painted with a paint of the same color as the surface of the outer cover 12 (usually white) to make it less noticeable. Also, instead of painting the outer peripheral surface of the insect screen 15, the insect screen 15 may be made of a resin of the same color as the surface of the outer cover 12. Note that, because the insect screen 15 is relatively thin, a metal mesh is generally used, but forming it from resin is also described in JP 2004-55848 A and JP 2006-195652 A.

Next, with regard to the fitting rib 14e of the outer cover 12 provided on the dark box base 14, its upper surface and its inner peripheral surface (tapered surface) on the dark box side are painted with paint of a similar color to the surface of the outer cover 12. When the installed sensor is viewed from directly below, the rib 14e is almost invisible because it overlaps with the head portion 21 of the outer cover 12 and is hidden, but when viewed from diagonally below, the upper surface and inner peripheral surface (tapered surface) of the rib are visible, so these areas need to be painted with a similar color to the outer cover. For this reason, the upper surface and inner peripheral surface (tapered surface) of the rib can be painted with paint of a similar color to the surface of the outer cover 12.
The dark box base 14 is often made of a black resin to prevent external light from being diffusely reflected by the surface of the light-shielding wall and reaching the light-receiving element of the photoelectric smoke sensor housed inside. Therefore, it is not desirable to form the dark box base 14 itself from a resin of the same color as the surface of the outer cover 12, and it is better to limit the application of paint to the upper surface and inner peripheral surface (tapered surface) of the fitting rib 14e of the outer cover 12, which is outside the smoke detection area.
In addition, the portions of the labyrinth-structured light-shielding wall 14d that come into contact with the inner surface of the insect screen 15 (portions marked with dots in Fig. 1) are also painted with paint of a similar color to the surface of the outer cover 12. This is to avoid the fact that if the light-shielding wall 14d were black, the inner light-shielding wall 14d would be visible through the meshes of the insect screen 15, the outer periphery of which is white, and would be conspicuous.

If a white-based paint is applied to the surface of the light-shielding wall 14d that contacts the insect screen, the function of preventing external light from reaching the light-receiving element inside by forming the dark box base 14 from a black-based resin may be impaired. However, there is a design method for the dark box base 14 to be formed from a gray resin close to black so that the light-receiving element can be checked for normal operation during initial inspection using the slight amount of light that leaks in from the outside. Therefore, there is no particular problem with applying a white-based paint to part of the surface of the light-shielding wall 14d that contacts the insect screen (the outermost surface), but if the paint is applied over a large area (expanding beyond the surface that contacts the insect screen (the outermost surface)), the function of the dark box base 14 will be impaired, so the area to be painted should be set appropriately in relation to the color of the resin of the dark box base 14, the labyrinth structure, etc.

On the other hand, with regard to the light-emitting member 23, the main body case 11 and the outer cover 12 are generally formed from a white resin or have a white paint applied to their surfaces to prevent the sensor from standing out when installed on a white ceiling surface of a building, whereas the ring-shaped light-emitting member 23 is formed from a transparent material as described above. Therefore, if left as is, the difference in surface color between the glossy light-emitting member 23 and the outer cover 12 will cause the light-emitting member 23 to stand out.
Therefore, in the smoke detector of this embodiment, an opaque paint of a similar color to the surface of the outer cover 12 is applied only to the exposed surface (upper surface) of the light emitting member 23 to form a thin coating 23b, as shown in Figure 4.

The coating 23b is opaque, but is formed so that when the LED on the circuit board 13 is turned on and the light is guided from the light guide portion 23a to the light emitting member 23, it leaks to the surface side of the outer cover 12 and shines brightly. For this reason, it is desirable to form the coating 23b as thin as possible. However, if the thickness of the coating 23b is made thin, it becomes easy to peel off, so it is best to determine the thickness by balancing the amount of light transmission and durability.

In the above explanation, an example has been given in which the light-emitting member is ring-shaped so that it is easily visible from all directions 360 degrees. However, even if a spot-shaped operation indicator light is provided, by forming a coating of a similar color to the outer cover on the part facing the outer cover, the smoke detector can be configured so that the operation indicator light is easy to see when it is lit, and is not conspicuous as it is the same color as the outer cover when it is not activated.
Furthermore, the spot-shaped operation indicator lamp may be formed of a bullet-shaped LED, and a coating of the same color as the outer cover may be formed on the surface of the outer cover of the operation indicator lamp.
Also, a coating 23b may be formed on the surface of the light emitting member 23, and the outer cover 12 itself may be made of a material that allows light to pass through to a certain extent. Incidentally, forming the cover of a detector from a resin that allows light to pass through, and making it possible to visually check the lighting state of the LED disposed inside, is also described in JP 2006-215865 A, although it is for a heat detector.

As described above, in the smoke detector of this embodiment, a thin coating 23b made of paint or the like is formed on the surface of the light emitting member 23, thereby preventing the light emitting member 23 from standing out. Also, since a paint of a similar color (generally white) to the surface of the outer cover 12 is applied to the outer peripheral surface of the insect screen 15, or the insect screen 15 is made of a resin of a similar color to the surface of the outer cover 12, the insect screen 15 can be prevented from standing out.
Furthermore, since the upper surface and inner peripheral surface of the fitting rib 14e of the outer cover 12 of the dark box base 14 are coated with paint of a similar color to the surface of the outer cover 12, it is possible to prevent any part of the rib 14e from standing out.

In the above embodiment, it has been described that the surface of the light emitting member 23, the outer peripheral surface of the insect screen 15, and the upper and inner peripheral surfaces of the fitting rib 14e of the outer cover 12 of the dark box base 14 are made in the same color as the surface of the outer cover 12, but since the insect screen 15 and the dark box base 14 are provided in a location inside the outer cover 12 where external light does not easily reach, the surface of the insect screen 15, the upper surface of the rib 14e of the dark box base 14, and the inner peripheral surface on the dark box side may be made in a lighter color than the surface of the light emitting member 23. This makes it possible to make the surface of the insect screen 15 and the rib 14e of the dark box base 14 even less noticeable when the smoke detector is installed on the ceiling surface of a building, etc.
In the above description, the coating is formed by applying paint, but the same effect can be obtained by forming the coating by applying a sticker.
Furthermore, by implementing the examples described above individually, it is possible to reduce the areas (areas) that do not blend in with the color of the installation environment, so that even when implemented individually, effects can be expected.

Second Embodiment
5 to 7 show a second embodiment of a smoke detector according to the present invention.
As shown in Figure 5, in the smoke detector of the second embodiment, the ring-shaped light-emitting member 23 is disposed in a position that is on the lower side when the outer cover 12 is installed, so that the ring-shaped light-emitting member 23 is covered by the outer cover 12 and cannot be directly seen from the outside, and a thin-walled portion 12f is provided in which the thickness of the portion of the outer cover 12 facing the upper surface of the ring-shaped light-emitting member 23 is thinner than the thickness of other portions.
As a result, when the operation indicator light (LED) is not lit, the ring-shaped light-emitting member 23 is completely invisible from the outside, and when the operation indicator light is lit, the light from the LED is guided to the ring-shaped light-emitting member 23 and emitted from the surface. This light passes through the thinner part of the outer cover 12, making the surface of the outer cover 12 bright in a ring shape, and making it possible to visually confirm the lit state of the operation indicator light.

Other than the light emitting member 23 being disposed under the outer cover 12, this embodiment is the same as the first embodiment, and the outer peripheral surface of the insect screen 15 is coated with paint of a similar color to the surface of the outer cover 12, or the insect screen 15 is formed from a resin of a similar color to the surface of the outer cover 12. In addition, the inner peripheral surface (inner surface and tapered surface) on the dark box side of the fitting rib 14e of the outer cover 12 provided on the dark box base 14 is coated with paint of a similar color to the surface of the outer cover 12. Furthermore, the portion of the light shielding wall 14d of the labyrinth structure that comes into contact with the inner surface of the insect screen 15 is also coated with paint of a similar color to the surface of the outer cover 12.

The ring-shaped light emitting member 23 has a plurality of small protrusions formed on its outer surface, and a fine hole is formed at a position corresponding to the above-mentioned protrusions on the inner surface of the light emitting member storage section near the opening 12A of the outer cover 12 that contacts the outer surface of the light emitting member 23, so that the light emitting member 23 is locked to the inside of the opening 12A of the outer cover 12 by engaging the protrusions with the fine hole. The light emitting member 23 may be configured to be locked to the outside of the rib 14e of the dark box base 14 by forming a plurality of small protrusions on the inner surface of the light emitting member 23 and forming a fine hole at a position corresponding to the above-mentioned protrusions on the outer surface of the rib 14e of the dark box base 14 that contacts the inner surface of the light emitting member 23, so that the protrusions engage with the fine hole.

Next, the specific structure of the portion of the outer cover 12 that covers the light emitting member 23 and faces the upper surface of the light emitting member 23 will be described with reference to Figures 6(A) to 6(C). Note that Figures 6(A) to 6(C) are enlarged views showing the cross-sectional shapes of the locking claw forming portion of the outer cover 12, the pillar forming portion of the smoke inlet, and other portions, respectively.

As shown in Fig. 6A, a thin wall portion 12f is provided on the inside of the locking claw 12d (left side in Fig. 6) at the portion of the outer cover 12 where the locking claw 12d is formed. A rib R is provided at the end of the thin wall portion 12f, and a drain hole 12j is formed by cutting out a part of this rib. In this way, the drain hole 12j cannot be seen from below and can be made inconspicuous.
In addition, as shown in Fig. 6(B), the portion where the pillar 12g of the smoke inlet (22) of the outer cover 12 is provided is formed to have the same thickness on the inside (left side in Fig. 6) and outside of the rib 12b of the outer cover 12. As shown in Fig. 6(C), the portion other than Fig. 6(A) and (B) is provided with a thin portion 12f.

As described above, a thin portion 12f is provided at the portion of the outer cover 12 facing the upper surface of the light emitting member 23, so that the light emitted from the light emitting member 23 passes through this thin portion 12f, causing the surface of the outer cover 12 to shine brightly, and even if the light emitting member 23 is covered by the outer cover 12, the visibility of the operation indicator light is hardly reduced.
In addition, by providing a thin-walled portion 12f near the opening 12A of the outer cover 12 as described above, it is expected that the strength of the base of the pillar supporting the outer cover 12, particularly the head portion 21, will be reduced. However, in this embodiment, as shown in Figure 6 (B), no thin-walled portion 12f is provided near the pillar forming portion of the smoke inlet of the outer cover 12, so that it is possible to prevent the strength of the base of the pillar 12g of the smoke inlet and the head portion 21 from being reduced when an external force acts on the head portion 21.
On the other hand, when considering the installation manner of the outer cover 12 (installation on the ceiling where it is difficult to reach), a slight decrease in strength is negligible, so by forming the thin-walled portion 12f continuously along the ring-shaped light-emitting member 23, a continuous ring display can be achieved.

Figure 7 shows the exterior of the smoke detector of the second embodiment installed on a ceiling, viewed from diagonally below. In Figure 7, the hatched area corresponds to the thin section 12f of the outer cover 12, and when the internal LED is turned on, the light is guided to the inner ring-shaped light-emitting member 23, causing the hatched area to shine evenly and brightly. Therefore, although there are some discontinuous areas in the example of Figure 7, it functions as an operation indicator light that lights up in a roughly ring shape, and thus has good visibility from all 360° directions, just like the smoke detector of the first embodiment (Figures 1 to 4).

Although the present invention has been described based on the embodiment, the present invention is not limited to the above embodiment.
It is sufficient that the light emitted from the surface of the outer cover can be seen when the smoke detector operation indicator light is activated (lights up), and that the thickness of the outer cover portion overlapping the ring-shaped light emitting member 23 when the outer cover is installed is thick enough to transmit light to the outside of the outer cover. As an example, the entire outer cover member 12 of Example 2 is formed with the same thickness as the thin portion, and a second outer cover is overlapped only on the outside of the operation indicator light (in the direction away from the sensor) in order to clarify the ring display of the operation indicator light and to increase the strength of the outer cover, and by reducing the amount of light transmitted on the outside of the operation indicator light (in the direction away from the sensor), the display state can be displayed in a clearer ring shape when viewed with the naked eye, and the strength of the outer cover can be ensured.
In the above embodiment, the number of pillars 12g forming the opening 22 as the smoke inlet of the outer cover 12 is four, but the number of pillars 12g may be three or five or more.
Furthermore, in the above embodiment, the light emitting surface (indicator light) of the light emitting member 23 is circular, but it does not have to be circular and may be elliptical or have a star-like or flower-like shape having multiple bends.

Other Embodiments
In the smoke detectors of the first and second embodiments described above, a configuration has been described in which the operation indicator light can be confirmed from the front side of the outer cover 12 (the side that can be seen when installed).
Next, a structure other than that of the first and second embodiments, which is inconspicuous when the operation indicator lamp is not in operation and has good visibility when the operation indicator lamp is in operation, will be described with reference to FIG.
The example shown in FIG. 8 has the same basic structure as the second embodiment, but differs in that the rib 14e is not integrally molded with the dark box base 14 but is made separate and is fitted and fixed in the same position as the rib formation position in FIG. 5, and that the separate rib 14e is made of a light-transmitting material.

By changing the above two points from the configuration of the smoke detector of the second embodiment, light can be projected from the light-emitting member 23 onto the surface of the insect screen (whose surface is a similar color to the outer cover 12) 15 through the light-transmitting rib 14e, and the operation of the operation indicator light can be indicated on the surface of the insect screen. This allows the appearance to be unified with the color of the outer cover when the operation indicator light is not in operation, and by matching the color of the outer cover to the color of the installation environment, a smoke detector that blends in with the environment can be realized. The upper surface and inner surface (tapered surface) of the rib 14e are painted with paint of a similar color to the surface of the outer cover 12.

The example in Figure 8 shows a structure that can both project light onto the surface of the insect screen and transmit light from the portion (thin portion) of the outer cover 12 that overlaps with the light-emitting member 23 in the smoke detector of the second embodiment; however, it may be configured to only project light onto the surface of the insect screen, which makes it inconspicuous when the operation indicator light is not activated and improves visibility when the operation indicator light is activated.
8, the ring-shaped light emitting member 23 is disposed under the outer cover 12, which cannot be seen from the outside, and the light is projected from the ring-shaped light emitting member 23 onto the surface of the insect screen 15 via the rib 14e, but the present invention is not limited to such a configuration. Since it is sufficient to realize the function of projecting light from the ring-shaped light emitting member 23 onto the surface of the insect screen 15, for example, in a smoke detector having a structure in which the rib 14e is not required on the dark box base 14, it is sufficient to configure the light projection path from the ring-shaped light emitting member 23 to the surface of the insect screen so as to be sufficiently secured. The ring-shaped light emitting unit 23 may be disposed inside the opening 12A, and in this case, each unit may be disposed so that the light from the light emitting unit is projected onto the insect screen when it is illuminated, and is visible from the outside.

10 Fire detector (photoelectric smoke detector)
11: Main body case 11c: Engagement portion 11d: Rib 12: Outer cover (cover member)
12A Opening 12b Inner rib 12d Locking claw (locking means)
12f Thin portion 12g Pillar forming smoke inlet 13 Circuit board 14 Dark box base 14d Light-shielding wall 14e Rib 15 Insect screen 16 Dark box cover 19A Light-emitting element 19B Light-receiving element 21 Head portion of outer cover 22 Opening (smoke inlet)
23 Light emitting member 23b Coating film (coating film)

Claims (5)

A smoke detector that includes a housing made of a main body and a cover member covering the upper side of the main body, a detection unit equipped with a photoelectric smoke sensor, and a circuit board equipped with an electronic circuit that detects the occurrence of a fire based on a signal from the detection unit, and that is equipped with an insect screen that is visible from the outside,
The cover member is provided with a cover body having an opening facing the sensing unit, a head portion covering the sensing unit, and a plurality of pillars connecting the head portion and the cover body, and a smoke inlet is formed between each of the plurality of pillars;
The smoke detector has a light emitting portion constituting an operation indicator light , and the light emitting portion is disposed on a surface of the cover member at a position that can be seen from directly below when the smoke detector is installed on a ceiling surface ,
A smoke detector comprising: a coating layer that transmits light and has a color similar to the surface color of the cover member so as to cover the light emitting portion. The smoke detector according to claim 1, characterized in that the operation indicator light is annular and is located near the opening of the cover member and on the outside of the column. The smoke detector according to claim 1 or 2, characterized in that the coating layer is a coating formed on the exposed surface of the light emitting portion. The insect screen is housed inside the housing and is disposed so as to face the smoke inlet and surround the sensor unit,
4. The smoke detector according to claim 1 , wherein the insect screen has an outer surface formed with a layer having a color similar to the surface color of the cover member. The sensing unit includes a dark box having the photoelectric smoke sensor built therein and a dark box base for holding the dark box, the dark box having an internal storage space for storing the photoelectric smoke sensor and a light-shielding wall having a labyrinth structure provided on the outside of the storage space,
5. The smoke detector according to claim 4 , wherein at least a portion of said light blocking wall that comes into contact with said insect screen is colored in a similar color to the surface color of said cover member.

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