JP6781022B2 - Fire detector - Google Patents

Description

The present invention relates to a technique that is effective when applied to a fire detector, particularly a photoelectric fire detector (smoke detector) using a light receiving element, or a composite fire detector that detects smoke and heat or gas.

Conventionally, as a fire detector, a photoelectric smoke detector that detects smoke by receiving scattered light emitted by a light emitting element with a light receiving element, a heat sensitive element such as a thermista, or a harmful gas such as CO is detected. Combined fire detectors with additional gas sensors to detect smoke and heat or gas are known.
Smoke detectors or hot smoke composite type detectors have a light emitting element and a light receiving element that are offset from each other in a dark box that has a light-shielding wall with a labyrinth structure that prevents light from entering from the outside. When smoke flows into the dark box when a fire breaks out, the light emitted from the light emitting element is scattered by the smoke, and when the light receiving element detects the scattered light, it is judged that a fire has occurred and an alarm is issued. There is something that has been done.

By the way, in a fire detector, water generated by rain leakage or dew condensation may travel along the ceiling surface and enter the detector case, causing a circuit malfunction. Therefore, the water that has entered the sensor cover, which is a member of the sensor housing (case) and is located on the lower side of the building when it is installed on the ceiling surface, is transmitted through the ceiling surface and collected in the cover. An invention has been proposed in which a drainage hole is provided for discharging the water to the outside (see, for example, Patent Documents 1 and 2).

Japanese Unexamined Patent Publication No. 2003-141653 Japanese Unexamined Patent Publication No. 2013-8084

However, in both the detectors of Patent Documents 1 and 2, since the drain hole is provided at a position where it can be seen from below the sensor cover, the appearance is poor and the drain hole is used for a long period of time. There is a problem that dust may enter the inside of the sensor, or the drain hole itself may become clogged and the original function may not be performed.

The present invention has been made by paying attention to the above-mentioned problems, and an object of the present invention is to provide a drain hole for discharging water that has entered the sensor cover along the ceiling surface, particularly downward. The purpose is to provide a fire detector that can drain water without being installed in a part that can be seen from (the floor side at the time of installation).
Another object of the present invention is to provide a fire detector in which water does not collect in the housing (case) of the detector.

In order to achieve the above object, the present invention
Inside the housing consisting of the main body case and the cover member that covers the upper side of the main body case, there is a sensing unit that detects changes in the monitoring target and an electronic circuit that detects the occurrence of a fire based on the signal from the sensing unit. In the fire detector that houses the mounted circuit board
An opening facing the sensing portion is formed in the cover member.
An outer rib and an inner rib that project upward when the main body case is installed on the ceiling surface of the building are provided near the outer edge portion of the cover member and the edge portion of the opening portion, respectively.
The main body case is connected to the cover member so that a part of the peripheral wall thereof is in contact with the inner rib.
One or two or more drain holes connecting the peripheral wall of the main body case and the contact portion between the inner ribs are formed in a portion of the cover member closer to the opening than the inner ribs.
The structure is such that the water that has entered the inside of the cover member can flow out through the gap of the contact portion and the drain hole.

According to the fire detector having the above configuration, the inner rib provided on the cover member is formed with one or more drain holes connected to the contact portion between the peripheral wall of the main body case and the inner rib. Therefore, the water that has entered the inside of the cover member can move from the drain hole to the contact portion between the peripheral wall of the main body case and the inner rib, and can be discharged to the outside by the capillary phenomenon.

Here, preferably, the peripheral wall of the main body case is formed so that its outer diameter is smaller than the inner diameter of the inner rib .
Ribs projecting outward are provided on the outer surface of the peripheral wall of the main body case, the lower surface of the ribs comes into contact with the tip surface of the inner ribs, and the lower surface of the ribs and the inner surface of the peripheral wall of the main body case. The drain hole is formed so as to be connected to the contact portion with the tip surface of the rib.
The cover member and the main body case are coupled to each other in a state where the outer surface on the tip end side of the peripheral wall of the main body case is in contact with the inner side surface of the inner rib.

According to this configuration, the water that has entered the inside of the cover member passes through the contact portion between the lower surface of the rib of the peripheral wall of the main body case and the tip surface of the inner rib by the capillary phenomenon from the drain hole, and the tip of the peripheral wall of the main body case. It can be discharged to the outside through the contact portion between the outer side surface and the inner surface of the inner rib.

Further, preferably, the cover member and the main body case are provided with engaging claws and engaging holes that can be engaged with each other, and the cover member and the main body case are provided with the locking claws and engaging holes. It is configured to be connected by engagement.
According to such a configuration, since the main body case and the cover member are integrated by the engagement of the locking claw and the engaging portion instead of the bolt, they are not strongly connected so as to maintain airtightness, and the peripheral wall of the main body case A slight gap is formed between the rib of the sensor and the inner rib of the sensor cover, so that the capillary phenomenon can be effectively exerted and the water that has entered the inside of the cover member can be discharged to the outside.

Further, preferably, one or more second drain holes are formed in the outer rib.
According to this configuration, since the outer rib is also formed with a drain hole in addition to the inner rib, even if the amount of water that has entered the inside of the cover member is large, the water that has entered is quickly discharged to the outside. Can be made to.

Further, preferably, a light emitting member for emitting light is provided inside the contact portion between the outer surface on the tip end side of the peripheral wall of the main body case and the inner surface of the inner rib.
The gap between the outer surface on the tip end side of the peripheral wall of the main body case and the inner side surface of the inner rib is configured to communicate with the gap at the contact portion between the light emitting member and the main body case.
According to such a configuration, the water discharged to the outside of the main body case and the sensor cover by the capillary phenomenon of the gap between the peripheral wall of the main body case and the inner rib from the drain hole is transferred between the light emitting member and the main body case. Since it moves to the gap between the contact portions and is discharged, it is possible to prevent water from moving toward the sensing portion inside the light emitting member and deteriorating the sensing function.

According to the present invention, drainage can be performed without providing a drainage hole for draining water that has entered the sensor cover through the ceiling surface, particularly in a portion that can be seen from below (the floor surface side at the time of installation). It is possible to realize a fire detector that can be used. In addition, there is an effect that it is possible to realize a fire detector in which water does not collect in the housing (case) of the detector.

It is an exploded perspective view which shows one Embodiment of the photoelectric fire detector as an example of the fire detector which concerns on this invention. FIG. 5 is a perspective view of the sensor cover constituting the sensor of the embodiment shown in FIG. 1 turned upside down and viewed from diagonally above. (A) is an enlarged cross-sectional view of the inner rib of the sensor cover and the forming portion of the locking piece (B) is an enlarged cross-sectional view of the drainage hole forming portion of the sensor cover, and (C) is (A) of the sensor cover. It is a cross-sectional enlarged view of the formation part of the inner rib and the step portion other than (B). It is a vertical cross-sectional perspective view which shows the state which assembled the sensor of an embodiment in the cross section. It is an enlarged perspective view of the main part which shows the light emitting part of the sensor cover in the state which assembled the sensor in an enlarged manner.

Hereinafter, an embodiment of a photoelectric fire detector (smoke detector) to which the present invention is applied will be described with reference to the drawings.
The photoelectric fire detector (hereinafter, simply referred to as a detector) 10 of the present embodiment is a detector capable of detecting smoke generated by a fire, and is installed on the ceiling surface of a building or the like for use. It is configured in. In the following description, unless otherwise specified, the upper side is the lower side and the lower side is the upper side when the sensor 10 is installed on the ceiling surface of the building.

As shown in FIG. 1, the sensor 10 of the present embodiment has a housing recess 11A for housing the sensing portion, and has a cylindrical main body case 11 for mounting on the ceiling surface of a building and a dome shape. A housing having a housing space is formed by the main body case 11 and the sensor cover 12 including a sensor cover 12 that covers the entire upper side of the main body case 11.
Further, the sensor 10 includes a circuit board 13 housed and fixed in the housing recess 11A of the main body case 11, a dark box base 14 having a light-shielding wall having a labyrinth structure and mounted on the circuit board 13. A cylindrical insect net 15 that is engaged and placed inside the edge of the dark box base 14, and a bottomed cylindrical insect net 15 that is sandwiched between the insect net 15 and engaged with the dark box base 14 to form a dark box. A dark box cover 16 is provided, and these components are housed in the housing, and the main body case 11 and the sensor cover 12 are combined to form a sensor.

The main body case 11 constitutes the lower housing wall of the sensor 10, and the lower surface of the main body case 11 is connected to a mounting base (not shown) previously installed on the ceiling surface to attach the sensor 10. Three connecting metal fittings 17 for fixing to the ceiling surface are provided (one of them is visible in FIG. 1). Further, the main body case 11 is provided with three boss portions 11b through which screws 18 for fixing the circuit board 13 and the dark box base 14 housed in the housing recess 11A are inserted (1 of them in FIG. 1). I can see the individual). Further, the outer peripheral wall of the main body case 11 is provided with an engaging portion 11c to which the claw of the locking piece of the sensor cover 12, which will be described later, engages.

The dark box base 14 is provided with a storage portion 14a for accommodating a light emitting element 19A such as an LED (light emitting diode) and a storage portion 14b for accommodating a light receiving element 19B such as a photodiode, and the storage portions 14a and 14b. On the bottom wall of the The tip of the LED penetrates the circuit board 13 and is connected by flow soldering or the like.

Further, the dark box base 14 is provided with two locking pieces (hooks) 14c protruding toward the circuit board 13 side (downward in the figure), and the tips of these locking pieces 14c are attached to the circuit board 13. By engaging with the formed engagement hole 13c, the dark box base 14 and the circuit board 13 are integrated. The circuit board 13 is composed of a printed wiring board on which electronic components such as resistors, capacitances, and ICs (semiconductor integrated circuits) that form an electronic circuit for fire detection are mounted on the upper surface and the lower surface, and a screw is inserted into the board. Three holes 13a are formed, and the main body case 11 is formed by a screw 18 inserted through the screw hole of the connecting metal fitting 17 and the boss portion 11b of the bottom wall of the main body case 11 and inserted into the screw insertion hole 13a of the circuit board 13. It is fixed in the accommodating recess 11A (see FIG. 4).

The light receiving element 19B is configured to be inserted into the storage portion 14b while being housed in the electromagnetic shield case 20 made of a conductive material. Further, the dark box cover 16 is provided with light-shielding walls 16a and 16b formed so as to surround the inner element corresponding to the storage portions 14a and 14b of the dark box base 14.
On the other hand, the sensor cover 12 is formed with a circular opening 12A in the center of which the upper part of the dark box can protrude, and a disk-shaped lid 16c of the dark box cover 16 protruding from the opening 12A. A head cover 21 that is engaged with the edge portion of the head cover 21 is provided, and a plurality of openings communicating with the opening 12A are formed along the circumferential direction between the head cover 21 and the upper wall of the sensor cover 12. The opening is configured to function as a smoke inlet 22 that allows outside smoke to flow into the case.

Further, a light emitting member 23 made of a transparent member formed in a ring shape is fitted to the edge of the opening 12A in the center of the sensor cover 12. A pair of rod-shaped light guide portions 23a formed so as to hang downward are coupled to the light emitting member 23, and the light at the tip (lower end) of one of the light guide portions 23a is connected. The incident portion (end face) is configured to face the light emitting diode (LED) for operating state notification mounted on the circuit board 13 (not shown).

Next, the drainage structure provided on the sensor cover 12 will be described with reference to FIGS. 2 and 3. Of these, FIG. 2 is a perspective view of the sensor cover 12 constituting the sensor of FIG. 1 turned upside down and viewed from diagonally above, and FIGS. 3 (A) to 3 (C) are locking claw forming portions of the sensor cover 12. , It is a cross-sectional enlarged view which shows the detail of the drainage hole forming part and the other part.
As shown in FIG. 2, an outer rib 12a erected upward (downward in FIG. 1) is provided on the outer edge of the sensor cover 12 and is slightly separated from the opening end of the opening 12A of the sensor cover 12. An inner rib 12b erected upward (downward in FIG. 1) is provided at the position, and an annular recess is formed between the outer rib 12a and the inner rib 12b. The outer rib 12a is formed with first drain holes 12c at four positions at intervals of approximately 90 ° by cutting out a part thereof.

Further, at a position having substantially the same radius as the inner rib 12b and slightly closer to the center side, the height is sufficiently higher than the height of the inner rib 12b, and the outer peripheral wall of the main body case 11 is engaged. Locking claws 12d that can be engaged with the portions 11c (three places) are formed at three places at intervals of approximately 120 °, and locking claws are formed on the inner ribs 12b corresponding to the locking claws 12d. Notches 12e (3 locations) having a width slightly wider than the width of 12d are formed. Further, as shown in FIGS. 3A to 3C, a step portion 12f higher than the inner rib 12b is formed inside the inner rib 12b, that is, at a position near the center of the cover, and the step portion 12f and the step portion 12f are formed. An annular fitting groove 12g for fitting the tip of the outer peripheral wall of the main body case 11 is formed between the inner rib 12b and the inner rib 12b.

As shown in FIG. 1, engaging portions 11c are formed at three locations on the upper part of the peripheral wall of the main body case 11, and project outwardly at a position slightly downward from the upper end. A ring-shaped rib 11d is formed. When the sensor cover 12 is attached to the main body case 11, the locking claws 12d of the sensor cover 12 shown in FIG. 3A are integrated with the engaging portion 11c of the main body case 11. At the same time, the height of the rib is set so that the lower surface of the rib 11d comes into contact with the upper end surface of the inner rib 12b of the sensor cover 12. Since the main body case 11 and the sensor cover 12 are integrated by the engagement between the locking claw 12d and the engaging portion 11c instead of the bolt, they are not strongly coupled so as to maintain the airtightness, and the main body case 11 There is a slight gap between the lower surface of the rib 11d and the upper end surface of the inner rib 12b of the sensor cover 12.

Further, on the outer side of the step portion 12f, that is, on the side close to the inner rib 12b, second drain holes 12h are provided at four locations at intervals of approximately 90 °. The second drain hole 12h is not particularly limited, but is formed so as to form an inverted L shape from the outer wall to the upper surface wall of the step portion 12f as shown in FIG. 3 (B). There is. In FIG. 2, the two through holes 12i formed on the upper surface of the step portion 12f are holes through which the two light guide portions 23a provided in the ring-shaped light emitting member 23 are inserted. Is.

Next, the drainage structure provided on the sensor cover 12 will be described with reference to FIGS. 4 and 5. FIG. 4 is a vertical cross-sectional perspective view showing a cross-sectional view of the assembled state of the sensor of the embodiment, and FIG. 5 is an enlarged perspective view of a main part showing an enlarged light emitting portion of the sensor cover 12 in the assembled state of the sensor. Is.
The water that has entered the sensor from the outside along the ceiling surface collects in the annular recess between the outer rib 12a and the inner rib 12b of the sensor cover 12. When the amount of water that has entered is large, most of it overflows from the first drain hole 12c provided in the outer rib 12a, as shown by the arrow A in FIG.

In addition, a part of the infiltrated water is caused by the capillary phenomenon on the lower surface of the rib 11d of the main body case 11 (the surface on the floor side in FIG. 1) and the upper end surface of the inner rib 12b of the sensor cover 12 (on the ceiling side in FIG. 1). It enters the gap between the surface) and moves inward. Then, through the second drain hole 12h (see FIG. 5) provided in the step portion 12f, a capillary phenomenon causes a gap between the light emitting member 23 fitted to the head portion of the sensor cover 12 and the light emitting member 23. It exudes and falls as water droplets as shown by arrow B in FIG.
On the other hand, when the amount of water that has entered the sensor is small, the water that has accumulated in the recess of the sensor cover 12 moves inward from the notch 12e provided in the inner rib 12b, as shown by the arrow C in FIG. It moves toward and moves into the gap between the side surface of the inner rib 12b of the sensor cover 12 and the side surface of the rib 11d of the main body case 11 due to the capillary phenomenon, and moves toward the second drain hole provided in the step portion 12f. Through 12h, it seeps into the gap between the light emitting member 23 and the light emitting member 23 due to the capillary phenomenon and falls as water droplets.

As described above, in the fire detector of the present embodiment, the outer ribs 12a and inner ribs 12b of the sensor cover are provided with drain holes 12c and 12h, and the gap between the ribs of the sensor cover and the main body case is formed. Since the structure is such that the water that has entered due to the capillary phenomenon is exuded by using the gap between the sensor cover and the light emitting member 23, it can be seen directly from the outside, especially from the lower side of the sensor (the floor side at the time of installation). Since the drain hole is not provided at the position, it is possible to prevent the sensor from being unsightly. Further, with long-term use, it is possible to prevent dust from entering the inside of the sensor through the drain hole, or the drain hole itself is clogged and cannot perform its original function.

Although the present invention has been described above based on the embodiment, the present invention is not limited to that of the above embodiment. For example, in the above embodiment, the one applied to the fire detector provided with the ring-shaped light emitting member 23 has been described, but it can also be applied to the type fire detector not provided with the light emitting member 23.
Further, in the above embodiment, the outer peripheral wall (outer rib 12a) and the inner peripheral wall (step portion 12f) of the sensor cover are provided with drain holes, respectively, but only the inner peripheral wall (step portion 12f) is provided with a drain hole. The drain hole of the outer peripheral wall (outer rib 12a) may be omitted. As a result, the drain hole is completely invisible from the outside, and the appearance of the sensor can be further improved.

Further, in the above embodiment, the present invention has been described in which the present invention is applied to a smoke detector having a light emitting element and a light receiving element, but the present invention is not limited thereto, and the present invention is not limited thereto, such as a pyroelectric element and a thermistor for detecting infrared rays. It can be widely applied to a heat-sensitive element or an element such as a gas sensor that detects harmful gas such as CO, and a fire detector having a built-in circuit board that detects a fire based on a signal from these elements.

10 Fire detector (photoelectric smoke detector)
11 Main body case 11c Engaging part (locking means)
11d rib 12 sensor cover 12a outer rib 12b inner rib 12c drain hole 12d locking claw (locking means)
12e Notch 12h Drain hole 12g Fitting groove 13 Circuit board 14 Dark box base 16 Dark box cover 19A Light emitting element 19B Light receiving element 23 Light emitting member

Claims (5)

Inside the housing consisting of the main body case and the cover member that covers the upper side of the main body case, there is a sensing unit that detects changes in the monitoring target and an electronic circuit that detects the occurrence of a fire based on the signal from the sensing unit. In the fire detector that houses the mounted circuit board
An opening facing the sensing portion is formed in the cover member.
An outer rib and an inner rib that project upward when the main body case is installed on the ceiling surface of the building are provided near the outer edge portion of the cover member and the edge portion of the opening portion, respectively.
The main body case is connected to the cover member so that a part of the peripheral wall thereof is in contact with the inner rib.
One or two or more drain holes connecting the peripheral wall of the main body case and the contact portion between the inner ribs are formed in a portion of the cover member closer to the opening than the inner ribs.
A fire detector characterized in that water that has entered the inside of the cover member can flow out through the gap of the contact portion and the drain hole. The outer diameter of the peripheral wall of the main body case is formed to be smaller than the inner diameter of the inner rib .
Ribs projecting outward are provided on the outer surface of the peripheral wall of the main body case, the lower surface of the ribs comes into contact with the tip surface of the inner ribs, and the lower surface of the ribs and the inner surface of the peripheral wall of the main body case. The drain hole is formed so as to be connected to the contact portion with the tip surface of the rib.
The first aspect of the present invention is characterized in that the cover member and the main body case are coupled to each other in a state where the outer surface on the tip end side of the peripheral wall of the main body case is in contact with the inner side surface of the inner rib. Described fire detector. The cover member and the main body case are provided with engaging claws and engaging holes that can be engaged with each other, and the cover member and the main body case are connected by engaging the locking claws and the engaging holes. The fire detector according to claim 2, wherein the fire detector is configured to be such. The fire detector according to claim 3, wherein one or more second drain holes are formed in the outer rib. A light emitting member for emitting light is provided inside the contact portion between the outer surface on the tip end side of the peripheral wall of the main body case and the inner surface of the inner rib.
The gap between the outer surface on the tip end side of the peripheral wall of the main body case and the inner side surface of the inner rib is configured to communicate with the gap at the contact portion between the light emitting member and the main body case. The fire detector according to any one of claims 1 to 4.

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