Smoke detector

Abstract

To reduce possibility of a non-fire alarm or detection omission of fire caused by intrusion of insects.SOLUTION: A smoke detector includes a body base plate 1. The body base plate 1 includes a cylindrical wall 103 forming a smoke detection space, and a rib 105 having both ends connected to an outer surface of the cylindrical wall 103 and forming a light-receiving unit housing space relative to the outside surface. Under the body base plate 1, a substrate is arranged substantially in parallel. An end portion of the substrate abuts on the outer surface and covers the light-receiving unit housing space. The rib 105 extends from a lower surface of the body base plate 1 toward the substrate so as to prevent intrusion of insects into the light-receiving unit housing space.SELECTED DRAWING: Figure 7

Description

Technical Field

[0001] The present invention relates to a smoke detector.

Background Art

[0002] Conventionally, a scattered light type smoke detector has been known (see, for example, Patent Document 1). A scattered light type smoke detector generally includes a dark box, a pair of light emitting elements, and a light receiving element. When smoke flowing into the dark box scatters the light of the light emitting element, and the scattered light is received by the light receiving element, a fire is detected.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In such a smoke detector, insects such as spiders may enter. When an insect enters the smoke detector and gets into its dark box, the light of the light emitting element may be scattered by the entering insect, and the scattered light may be received by the light receiving element. If it is received by the light receiving element, a fire may be detected even though there is actually no fire. As another possibility, the light emission by the light emitting element or the light reception by the light receiving element may be obstructed by the entering insect, and it is conceivable that a fire cannot be detected even though there is actually a fire.

[0005] The present invention has been made in view of such circumstances, and an object thereof is to reduce the possibility of false non-fire alarms or missed detection of fires caused by the entry of insects.

Means for Solving the Problems

[0006] To solve the above problems, the smoke detector according to the present invention includes a main body base plate and a substrate disposed substantially parallel to the main body base plate below the main body base plate. The main body base plate is provided on the lower surface of the main body base plate and has a cylindrical wall that forms a smoke detection space, and both ends are connected to the outer surface of the first wall portion that constitutes the cylindrical wall, and a first rib that forms a light receiving portion accommodation space between the first wall portion and extends from the lower surface of the main body base plate toward the substrate so as to inhibit the intrusion of insects into the light receiving portion accommodation space. The substrate has an end portion that abuts or is close to the outer surface of the first wall portion, covers the light receiving portion accommodation space, and on the upper surface of the substrate, a light emitting portion that irradiates light into the smoke detection space and a light receiving portion that is accommodated in the light receiving portion accommodation space and receives light scattered by hitting smoke particles after being irradiated from the light emitting portion through a first light passing hole formed in the first wall portion are mounted.

Advantages of the Invention

[0007] According to the present invention, the possibility of false alarms or missed detection of fires caused by the intrusion of insects can be reduced.

Brief Description of the Drawings

[0008]

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DETAILED DESCRIPTION OF THE INVENTION

[0009] 1. Embodiment 1-1. Configuration of the smoke detector 100 The smoke detector 100 according to an embodiment of the present invention will be described with reference to FIGS. 1 to 5. FIGS. 1 to 4 referred to in this description are the bottom view, side view, plan view, and exploded perspective view of the smoke detector 100. FIG. 5 is the cross-sectional view taken along line A-A in FIG. 3.

[0010] Among these figures, as particularly shown in FIGS. 4 and 5, the smoke detector 100 includes a circular main body base plate 1, a substantially L-shaped substrate 2 and a circular speaker 3 disposed substantially parallel to the lower side of the main body base plate 1, a substantially circular middle plate 4 disposed substantially parallel to the lower side of the substrate 2, and a bottomed cylindrical main body cover 5 fixed to the main body base plate 1 while accommodating the main body base plate 1, the substrate 2, the speaker 3, and the middle plate 4. Hereinafter, each component of this smoke detector 100 will be described in order.

[0011] 1-2. Structure of the main body base plate 1 First, the main body base plate 1 will be described with reference to FIGS. 6 to 8. FIG. 6 referred to in this description is a bottom view of the main body base plate 1, and FIGS. 7 and 8 are bottom perspective views with different viewpoints.

[0012] As shown in these figures, the main body base plate 1 has a battery accommodation portion 101 formed from its center to its peripheral portion. This battery accommodation portion 101 protrudes convexly on the lower surface side of the main body base plate 1 and is concave on the upper surface side, and a cylindrical battery is accommodated in the recess on the upper surface side. The battery accommodated in this battery accommodation portion 101 is connected to the substrate 2 and supplies power to the circuit on the substrate 2.

[0013] The main body base plate 1 also has a speaker accommodation portion 102 formed adjacent to the battery accommodation portion 101. This speaker accommodation portion 102 is a substantially C-shaped rib protruding vertically from the lower surface of the main body base plate 1. The speaker 3 is accommodated in this speaker accommodation portion 102.

[0014] This speaker accommodation portion 102 has a hook 1021 on its outer peripheral surface. This hook 1021 is locked to a locking hole 422 (see FIG. 18) of the middle plate 4 described later.

[0015] The main body base plate 1 also has a cylindrical wall 103 formed on the axis of the battery accommodated in the battery accommodation portion 101. This cylindrical wall 103 is an isosceles trapezoid-shaped rib protruding vertically from the lower surface of the main body base plate 1. The lower end portion of this cylindrical wall 103 abuts on the upper surface of the middle plate 4 to form a smoke detection space.

[0016] This cylindrical wall 103 is composed of four linear wall portions 1031, 1032, 1033, and 1034. Among these, the wall portion 1033 has a light passage hole 1035 for the light emitting portion 205, which will be described later, to irradiate light into the smoke detection space. Also, the wall portion 1034 has a light passage hole 1036 for the light receiving portion 206, which will be described later, to receive light from the smoke detection space.

[0017] The main body base plate 1 also has a substantially U-shaped rib 104 whose both ends are connected to the outer surface of the wall portion 1033. This rib 104 forms a light emitting portion accommodation space between it and the wall portion 1033.

[0018] This rib 104 extends vertically from the lower surface of the main body base plate 1 toward the substrate 2 so as to prevent insects from entering the light emitting portion accommodation space, and abuts on the upper surface of the substrate 2.

[0019] The main body base plate 1 also has a U-shaped rib 105 whose both ends are connected to the outer surface of the wall portion 1034. This rib 105 forms a light receiving portion accommodation space between it and the wall portion 1034.

[0020] This rib 105 extends vertically from the lower surface of the main body base plate 1 toward the substrate 2 so as to prevent insects from entering the light receiving portion accommodation space. There is a slight gap between this rib 105 and the substrate 2, and this gap is substantially the same as the size of the mesh of the insect-proof net ring 6 (see FIG. 4), which will be described later. That is, it is sized to prevent insects from passing through.

[0021] The main body base plate 1 also has a substrate mounting portion 106. This substrate mounting portion 106 is a rib that projects vertically from the lower surface of the main body base plate 1 and is formed so as to surround a substantially L-shaped region. The peripheral edge portion of the upper surface of the substrate 2 is attached to this substrate mounting portion 106.

[0022] This board mounting portion 106 has two hooks 1061 and 1062 on its outer surface. These two hooks 1061 and 1062 are respectively locked to the locking holes 423 and 424 (see FIG. 18) of the middle plate 4 described later.

[0023] Also, the main body base plate 1 has two pushing portions 107A and 107B formed on the opposite side of the speaker housing portion 102 with the battery housing portion 101 interposed therebetween. These two pushing portions 107A and 107B are rod-shaped members and are formed by forming a U-shaped through groove in the main body base plate 1.

[0024] Among these two pushing portions 107A and 107B, the pushing portion 107A is arranged to contact the registration switch 209 described later. When the pushing portion 107A is pushed by the user, the registration switch 209 is pressed down. On the other hand, the pushing portion 107B is arranged to contact the erasure switch 210 described later. When the pushing portion 107B is pushed by the user, the erasure switch 210 is pressed down.

[0025] The main body base plate 1 also has two columnar antenna holders 108 and 109 that project vertically at its peripheral edge. Among these two antenna holders 108 and 109, the antenna holder 108 is arranged adjacent to the outer surface of the board mounting portion 106. This antenna holder 108 is inserted into the insertion hole 416 (see FIG. 15) of the middle plate 4 described later. Also, a U-shaped groove is formed at the tip of this antenna holder 108, and the antenna 212 is fitted into this groove.

[0026] On the other hand, the antenna holder 109 is arranged on the axis of the battery housed in the battery housing portion 101. This antenna holder 109 is inserted into the locking hole 425 (see FIG. 15) of the middle plate 4 described later. Also, a U-shaped groove is formed at the tip of this antenna holder 109, and the antenna 212 is fitted into this groove.

[0027] Further, this antenna holding portion 109 has a hook 1091 on its outer surface (in other words, the surface opposite to the surface facing the cylindrical wall 103). This hook 1091 is locked to a locking hole 425 (see FIG. 15) of a middle plate 4 described later.

[0028] Also, the main body base plate 1 has a pair of plate-like switch holding portions 110 and 111 that project vertically at its peripheral edge. This pair of switch holding portions 110 and 111 holds an illumination switch 8 described later.

[0029] Among this pair of switch holding portions 110 and 111, the switch holding portion 110 has a U-shaped groove and a C-shaped groove formed at its tip. Among these grooves, the shaft portion of the illumination switch 8 is fitted into the U-shaped groove, and the antenna 212 is fitted into the C-shaped groove. On the other hand, the switch holding portion 111 has a U-shaped groove formed at its tip. The shaft portion of the illumination switch 8 is fitted into this U-shaped groove. The above is the description of the main body base plate 1.

[0030] 1-3. Structure of Substrate 2 Next, the substrate 2 will be described with reference to FIGS. 9 to 11. FIGS. 9 to 11 referred to in this description are a bottom view, a plan view, and a bottom perspective view of the substrate 2.

[0031] As shown in these figures, the substrate 2 has a fan-shaped notch 201 with a central angle of approximately a right angle. In the region where this notch 201 is formed, the battery housing portion 101 of the main body base plate 1 and the speaker 3 are arranged. The speaker 3 arranged in this region is connected to the substrate 2.

[0032] Also, the substrate 2 has an isosceles trapezoid-shaped notch 202. In the region where this notch 202 is formed, the cylindrical wall 103 of the main body base plate 1 is arranged.

[0033] Also, the substrate 2 has a pair of rectangular notches 203 and 204 that face each other with the isosceles trapezoid-shaped notch 202 in between.

[0034] Also, a light emitting unit 205 is mounted on the upper surface of the substrate 2. This light emitting unit 205 is, for example, a light emitting diode. This light emitting unit 205 is housed in a light emitting unit accommodation space formed by the cylindrical wall 103 and the rib 104 of the main body base plate 1, and irradiates light into the smoke detection space formed by the cylindrical wall 103. At that time, the light emitting unit 205 irradiates light into the smoke detection space through the light passage hole 1035 of the cylindrical wall 103.

[0035] Also, a light receiving unit 206 is mounted on the upper surface of the substrate 2. This light receiving unit 206 is, for example, a photodiode housed in a shield case. This light receiving unit 206 is housed in a light receiving unit accommodation space formed by the cylindrical wall 103 and the rib 105 of the main body base plate 1, and receives the light of the light emitting unit 205 scattered when hitting the smoke particles. At that time, the light receiving unit 206 receives the scattered light through the light passage hole 1036 of the cylindrical wall 103.

[0036] The light emitting unit 205 and the light receiving unit 206 are arranged along the isosceles trapezoid-shaped notch portion 202 so that their optical axes are not on the same straight line.

[0037] Also, an inspection switch 207 and a confirmation lamp 208 are mounted on the lower surface of the substrate 2. Among these, the inspection switch 207 is a switch used to test the internal circuit and battery life. This inspection switch 207 is designed to be pressed when the illumination switch 8 described later is pushed in. On the other hand, the confirmation lamp 208 is an LED for notifying the result of the test.

[0038] Also, a registration switch 209 and a deletion switch 210 are mounted on the upper surface of the substrate 2. The registration switch 209 is a switch used to set the wireless channel used by the smoke detector 100, and the deletion switch 210 is a switch used to delete the setting of the wireless channel.

[0039] Also, a connector 211 is mounted on the upper surface of the substrate 2.

[0040] Also, an antenna 212 made of a metal wire is connected to the substrate 2. This antenna 212 is composed of a straight portion 2121 and an arc portion 2122. One end of the straight portion 2121 is connected to a wireless communication circuit 215 (not shown), extends vertically from the lower surface of the substrate 2, and is inserted into the antenna hole 420 (see FIG. 15) of the middle plate 4. On the other hand, one end of the arc portion 2122 is connected to the other end of the straight portion 2121 and extends in an arc shape so as to surround the isosceles trapezoidal notch portion 202.

[0041] Also, a conductor 213 made of a metal wire is connected to the substrate 2. This conductor 213 is composed of a straight portion 2131 and an arc portion 2132. One end of the straight portion 2131 is connected to a ground (not shown) on the substrate 2 and extends along the longitudinal direction of the battery housing portion 101. On the other hand, one end of the arc portion 2132 is connected to the other end of the straight portion 2131 and extends in an arc shape so as to surround the speaker 3.

[0042] Also, a control circuit 214 (not shown) is mounted on the substrate 2. This control circuit 214 executes a fire detection process, a fire signal transfer process, and a wireless channel setting process, which will be described later.

[0043] Also, a wireless communication circuit 215 (not shown) is mounted on the substrate 2. This wireless communication circuit 215 performs wireless communication with other smoke sensors 100 and relay devices using the antenna 212. The above is the description of the substrate 2.

[0044] The substrate 2 described above has its peripheral portion on the upper surface attached to the substrate mounting portion 106 of the main body base plate 1. Also, the speaker 3 connected to the substrate 2 is fitted into the speaker housing portion 102 of the main body base plate 1. FIGS. 12 and 13 are a bottom view and a side view of the substrate 2 and the speaker 3 attached to the main body base plate 1 in this way. FIG. 14 is an enlarged view of part B in FIG. 12.

[0045] As shown particularly in FIG. 12 among these figures, in the region where the fan-shaped notch 201 of the substrate 2 is formed, the battery housing portion 101 of the main body base plate 1 is disposed. Further, in the region where the isosceles trapezoid-shaped notch 202 of the substrate 2 is formed, the cylindrical wall 103 of the main body base plate 1 is disposed. The notch 202 of the substrate 2 abuts on the outer surface of this cylindrical wall 103.

[0046] More specifically, as shown in FIG. 14, the notch 202 abuts on the outer surfaces of the wall portions 1031, 1033, and 1034 among the four wall portions 1031 to 1034 that constitute the cylindrical wall 103. Therefore, the substrate 2 covers the light emitting portion housing space and the light receiving portion housing space formed in the main body base plate 1. Further, the rectangular notch 203 of the substrate 2 forms a through hole 216 between it and the wall portion 1033. This through hole 216 is a through hole that communicates the space between the substrate 2 and the middle plate 4 and the light emitting portion housing space. Further, the rectangular notch 204 of the substrate 2 forms a through hole 217 between it and the wall portion 1034. This through hole 217 is a through hole that communicates the space between the substrate 2 and the middle plate 4 and the light receiving portion housing space.

[0047] Further, as shown in FIG. 12, the antenna 212 connected to the substrate 2 is sandwiched by the antenna holding portions 108 and 109 of the main body base plate 1 and the U-shaped groove formed at the tip of the switch holding portion 110.

[0048] 1-4. Configuration of the Middle Plate 4 Next, the middle plate 4 will be described with reference to FIGS. 15 to 18. FIGS. 15 to 18 referred to in this description are the bottom view, bottom perspective view, plan view, and plan perspective view of the middle plate 4.

[0049] As shown in these figures, the middle plate 4 has a substantially U-shaped notch 401 formed from its center to the peripheral portion. In the region where this notch 401 is formed, the battery housing portion 101 of the main body base plate 1 is disposed.

[0050] In addition, the middle plate 4 has an elliptical ventilation hole 402 formed on the side opposite to the notch 401 across its center. This ventilation hole 402 is a ventilation hole that communicates the space between the middle plate 4 and the main body cover 5 with the smoke detection space formed in the main body base plate 1.

[0051] Also, the middle plate 4 has three labyrinth walls 403 to 405 formed around the ventilation hole 402. These three labyrinth walls 403 to 405 are plate-like walls that project vertically from the lower surface of the middle plate 4. These three labyrinth walls 403 to 405 are formed so as to inhibit the inflow of external light into the ventilation hole 402 while not inhibiting the inflow of smoke into the ventilation hole 402.

[0052] Also, the middle plate 4 has a pair of rectangular locking holes 406 and 407 formed around the labyrinth walls 403 to 405. These two locking holes 406 and 407 are locking holes into which the hooks of the optical bench cover 7 (see Fig. 4) described later are locked.

[0053] Also, the middle plate 4 has eight antenna holding parts 408 to 415 formed radially around the labyrinth walls 403 to 405. These eight antenna holding parts 408 to 415 are substantially linear plate bodies that project vertically from the lower surface of the middle plate 4. These eight antenna holding parts 408 to 415 have notches at their tips, and the antenna 212 is fitted into these notches.

[0054] Also, the middle plate 4 has a rectangular insertion hole 416 formed at its peripheral edge. The antenna holding part 108 of the main body base plate 1 is inserted into this insertion hole 416.

[0055] Also, the middle plate 4 has a plurality of speaker holes 417 formed adjacent to the U-shaped notch 401. These plurality of speaker holes 417 are arranged under the speaker 3.

[0056] In addition, the middle plate 4 has a switch hole 418 and a display hole 419 formed adjacent to the U-shaped notch 401. Among these holes, the switch hole 418 is an insertion hole through which the inspection switch 207 is inserted. On the other hand, the display hole 419 is a light passage hole for passing the light of the confirmation lamp 208.

[0057] In addition, the middle plate 4 has an antenna hole 420 formed at its peripheral edge. This antenna hole 420 is an insertion hole through which the antenna 212 is inserted.

[0058] In addition, the middle plate 4 has a side wall 421 erected at the peripheral edge of its upper surface.

[0059] In addition, the middle plate 4 has three rectangular locking holes 422 to 424 formed in the side wall 421. Among these three locking holes 422 to 424, the hook 1021 of the main body base plate 1 is locked in the locking hole 422, the hook 1061 of the main body base plate 1 is locked in the locking hole 423, and the hook 1062 of the main body base plate 1 is locked in the locking hole 424.

[0060] In addition, the middle plate 4 has a locking hole 425 formed from its peripheral edge to the side wall 421. As shown in FIG. 16, this locking hole 425 is arranged so as to sandwich the labyrinth wall 404 between it and the ventilation hole 402. This locking hole 425 is composed of a rectangular hole portion formed at the peripheral edge and a rectangular hole portion formed in the side wall 421 connected to each other. Among these hole portions, the antenna holding portion 109 of the main body base plate 1 is inserted into the former hole portion. On the other hand, the hook 1091 of the main body base plate 1 is locked in the latter hole portion.

[0061] In addition, the middle plate 4 has a partition wall 426 that separates the ventilation hole 402 and the locking hole 425, and both ends of this partition wall 426 are connected to the side wall 421. This partition wall 426 is a plate body that protrudes vertically from the upper surface of the middle plate 4.

[0062] In addition, the middle plate 4 has a pair of ribs 427 and 428 formed to surround the vent hole 402 together with the partition wall 426. The pair of ribs 427 and 428 are formed to extend substantially vertically from the upper surface of the middle plate 4 toward the substrate 2. There is a slight gap between the pair of ribs 427 and 428 and the substrate 2, and this gap is substantially the same as the mesh size of the insect screen ring 6 (see FIG. 4) described later. That is, it is a size that inhibits the passage of insects.

[0063] Of the pair of ribs 427 and 428, the rib 427 is composed of a straight portion 4271 whose one end is connected to the partition wall 426, a U-shaped portion 4272 whose one end is connected to the other end of the straight portion 4271, and a straight portion 4273 whose one end is connected to the other end of the U-shaped portion 4272. On the other hand, the rib 428 is composed of a straight portion 4281 whose one end is connected to the partition wall 426 and a U-shaped portion 4282 whose one end is connected to the other end of the straight portion 4281. The lower end portion of the cylindrical wall 103 of the main body base plate 1 is fitted into the space formed by the pair of ribs 427 and 428 and the partition wall 426. The above is the description of the middle plate 4.

[0064] The middle plate 4 described above is attached to the main body base plate 1 so as to cover the substrate 2 and the speaker 3. At that time, the middle plate 4 is fixed to the main body base plate 1 by the hooks 1021, 1061, 1062, and 1091 of the main body base plate 1 being locked to the locking holes 422 to 425 of the middle plate 4. FIGS. 19 and 20 are a bottom view and a side view of the middle plate 4 attached to the main body base plate 1 in this way. FIG. 21 is a cross-sectional view taken along the line C-C of FIG. 20. FIG. 22 is an enlarged view of part D of FIG. 21.

[0065] As shown particularly in FIG. 19 among these figures, in the region where the notch 401 of the middle plate 4 is formed, the battery housing portion 101 of the main body base plate 1 is arranged. Further, the antenna holding portion 108 of the main body base plate 1 is inserted through the insertion hole 416 of the middle plate 4. Further, the antenna holding portion 109 of the main body base plate 1 is inserted through the locking hole 425 of the middle plate 4. Further, the antenna 212 is inserted through the antenna hole 420 of the middle plate 4. Further, the antenna 212 inserted through the antenna hole 420 is fitted into the notches of the antenna holding portions 408 to 415 of the middle plate 4. Further, the inspection switch 207 is inserted through the switch hole 418 of the middle plate 4. Further, the confirmation lamp 208 is visible from the display hole 419 of the middle plate 4.

[0066] Also, as shown particularly in FIG. 22, the lower end portion of the cylindrical wall 103 of the main body base plate 1 is fitted into the space formed by the partition wall 426 and the pair of ribs 427 and 428 of the middle plate 4. As a result, the partition wall 426 of the middle plate 4 is in contact with the outer surfaces of the wall portions 1032 to 1034 constituting the cylindrical wall 103. Further, the rib 427 of the middle plate 4 is in contact with the outer surfaces of the wall portions 1031 and 1034 constituting the cylindrical wall 103. In particular, both ends of the U-shaped portion 4272 of the rib 427 are in contact with the outer surface of the wall portion 1034 and surround the through hole 217. In addition, the upper end portion of this U-shaped portion 4272 is close to the substrate 2 to such an extent as to inhibit the passage of insects. Therefore, this U-shaped portion 4272 inhibits the intrusion of insects into the through hole 217 in the space between the middle plate 4 and the substrate 2.

[0067] Further, the rib 428 of the middle plate 4 is in contact with the outer surface of the wall portion 1033 constituting the cylindrical wall 103. In particular, both ends of the U-shaped portion 4282 of the rib 428 are in contact with the outer surface of the wall portion 1033 and surround the through hole 216. In addition, the upper end portion of this U-shaped portion 4282 is close to the substrate 2 to such an extent as to inhibit the passage of insects. Therefore, this U-shaped portion 4282 inhibits the intrusion of insects into the through hole 216 in the space between the middle plate 4 and the substrate 2.

[0068] 1-5. Structure of the main body cover 5 Next, the main body cover 5 will be described with reference to FIGS. 23 to 25. FIGS. 23 to 25 referred to in this description are the bottom view, side view, and plan view of the main body cover 5.

[0069] As particularly shown in FIG. 23 among these figures, the main body cover 5 has an oval switch hole 501 formed in its bottom plate portion. An illumination switch 8 (see FIG. 4) is fitted into this switch hole 501.

[0070] Also, as shown in FIG. 24, the main body cover 5 has a plurality of ventilation holes 502 formed on the lower side of its cylindrical portion. These ventilation holes 502 are ventilation holes for allowing smoke to flow into the space between the main body cover 5 and the middle plate 4.

[0071] Also, as shown in FIG. 25, the main body cover 5 has a pair of switch support portions 503A and 503B formed adjacent to the switch hole 501. This pair of switch support portions 503A and 503B has a U-shaped notch, and the shaft portion of the illumination switch 8 is fitted into this notch. The above is the description of the main body cover 5.

[0072] The main body cover 5 described above houses the main body base plate 1, the substrate 2, the speaker 3, and the middle plate 4, and is fixed to the main body base plate 1 (see FIG. 4). At that time, an insect-proof net ring 6 is attached to the middle plate 4 housed in the main body cover 5. More specifically, this insect-proof net ring 6 is attached so as to surround the ventilation holes 402 and the labyrinth walls 403 to 405 of the middle plate 4.

[0073] Then, an optical bench cover 7 is attached so as to cover the lower opening of the attached insect-proof net ring 6. This optical bench cover 7 has a disc portion, a star-shaped protrusion formed at the center of the upper surface of the disc portion, and a pair of hooks erected on the peripheral edge of the disc portion. When this optical bench cover 7 is attached to the middle plate 4, its disc portion covers the lower opening of the insect-proof net ring 6, its protrusion is inserted between the labyrinth walls 403 to 405 of the middle plate 4, and its pair of hooks are locked to the pair of locking holes 406 and 407 of the middle plate 4.

[0074] In addition, an illumination switch 8 is attached to the main body base plate 1 housed in the main body cover 5. This illumination switch 8 has an oval plate portion, a protruding portion that protrudes vertically from one end of the plate portion, a columnar portion that stands vertically at the other end of the plate portion, and a shaft portion formed at the base end of the columnar portion. Further, this illumination switch 8 is made of a translucent resin material containing a light diffusing material. When this illumination switch 8 is attached to the main body base plate 1, its protruding portion abuts against the inspection switch 207 of the substrate 2, its columnar portion is inserted between a pair of switch holding portions 110 and 111 of the main body base plate 1, and its shaft portion is fitted into the U-shaped grooves of the pair of switch holding portions 110 and 111.

[0075] As described above, after attaching the insect screen ring 6, the optical bench cover 7, and the illumination switch 8, the main body cover 5 is attached to the main body base plate 1. When the main body cover 5 is attached to the main body base plate 1, the plate portion of the illumination switch 8 is fitted into the switch hole 501 thereof. In addition, the shaft portion of the illumination switch 8 is clamped by a pair of switch support portions 503A and 503B of the main body cover 5 and a pair of switch holding portions 110 and 111 of the main body base plate 1.

[0076] 1-6. Operation Next, the function of the rib 105 of the main body base plate 1 will be described. As shown in FIG. 7, the rib 105 of the main body base plate 1 is a U-shaped rib whose both ends are connected to the outer surface of the cylindrical wall 103. In addition, as shown in FIG. 13, the lower end portion of this rib 105 is close to the substrate 2 to such an extent that it inhibits the passage of insects. Therefore, this rib 105 inhibits the intrusion of insects into the light receiving portion accommodation space formed between the rib and the cylindrical wall 103.

[0077] As described above, the main body base plate 1 has the pushing portions 107A and 107B (see FIG. 6). U-shaped through grooves are formed around these pushing portions 107A and 107B, and there is a possibility that insects may enter the device through these U-shaped through grooves. If an insect enters the device, the insect may proceed between the main body base plate 1 and the substrate 2 and reach the vicinity of the light receiving portion 206. At that time, assuming that there is no rib 105, the insect may enter on the optical axis of the light receiving portion 206, and the light reception of the light receiving portion 206 may be hindered. If the light reception of the light receiving portion 206 is hindered, even if a fire occurs, the fire cannot be detected. As another possibility, it is conceivable that the insect may enter the smoke detection space through the light passage hole 1036. If it enters the smoke detection space, the light of the light emitting portion 205 may hit the insect and scatter, and may be received by the light receiving portion 206. If the scattered light is received by the light receiving portion 206, a fire will be detected even though there is actually no fire.

[0078] On the other hand, if there is a rib 105, the intrusion of insects into the light receiving portion accommodation space is inhibited. Therefore, it is possible to reduce the possibility of false non-fire alarms or missed fire detections caused by the intrusion of insects as described above.

[0079] Next, the action of the rib 427 of the middle plate 4 will be described. As shown in FIG. 22, the rib 427 of the middle plate 4 has a U-shaped portion 4272. The U-shaped portion 4272 is a U-shaped rib whose both ends are in contact with the outer surface of the cylindrical wall 103 and surround the through hole 217. In addition, the upper end portion of the U-shaped portion 4272 is close to the substrate 2 to such an extent that it inhibits the passage of insects. Therefore, the U-shaped portion 4272 inhibits the intrusion of insects into the through hole 217 in the space between the middle plate 4 and the substrate 2.

[0080] As described above, the main body cover 5 has ventilation holes 502 (see Fig. 24). Also, as described above, the middle plate 4 has display holes 419 (see Fig. 15). There is a possibility that insects may enter the space between the middle plate 4 and the substrate 2 through these ventilation holes 502 and display holes 419. If an insect enters that space, the insect may advance through the space and reach near the through-hole 217. At that time, assuming there is no U-shaped portion 4272, the insect may enter the light-receiving unit accommodation space through the through-hole 217. If it enters the light-receiving unit accommodation space, the light reception of the light-receiving unit 206 may be obstructed by the insect. If the light reception of the light-receiving unit 206 is obstructed, even if a fire occurs, the fire cannot be detected. As another possibility, it is conceivable that the insect may enter the smoke detection space through the light passage hole 1036. If it enters the smoke detection space, the light of the light-emitting unit 205 hits the insect and scatters, and there is a possibility that it may be received by the light-receiving unit 206. If the scattered light is received by the light-receiving unit 206, a fire will be detected even though there is actually no fire.

[0081] On the other hand, if there is a U-shaped portion 4272, the intrusion of insects into the through-hole 217 is inhibited. Therefore, it is possible to reduce the possibility of false non-fire alarms or missed fire detections caused by the intrusion of insects as described above.

[0082] Next, the function of the rib 428 of the middle plate 4 will be described. As shown in Fig. 22, the rib 428 of the middle plate 4 has a U-shaped portion 4282. This U-shaped portion 4282 is a U-shaped rib whose both ends are in contact with the outer surface of the cylindrical wall 103 and surround the through-hole 216. In addition, the upper end portion of this U-shaped portion 4282 is close to the substrate 2 to such an extent that it inhibits the passage of insects. Therefore, this U-shaped portion 4282 inhibits the intrusion of insects into the through-hole 216 in the space between the middle plate 4 and the substrate 2.

[0083] As described above, the main body cover 5 has ventilation holes 502 (see Fig. 24). Also, as described above, the middle plate 4 has display holes 419 (see Fig. 15). There is a possibility that insects may enter the space between the middle plate 4 and the substrate 2 through these ventilation holes 502 and display holes 419. If an insect enters that space, the insect may advance through the space and reach the vicinity of the through hole 216. At that time, assuming there is no U-shaped portion 4282, the insect may enter the light-emitting portion accommodation space through the through hole 216. If it enters the light-emitting portion accommodation space, the light emission of the light-emitting portion 205 may be obstructed by the insect. If the light emission of the light-emitting portion 205 is obstructed, even if a fire occurs, the fire cannot be detected. As another possibility, it is conceivable that the insect may enter the smoke detection space through the light passage hole 1035. If it enters the smoke detection space, the light of the light-emitting portion 205 may hit the insect and scatter, and may be received by the light-receiving portion 206. If the scattered light is received by the light-receiving portion 206, a fire will be detected even though there is actually no fire.

[0084] On the other hand, if there is a U-shaped portion 4282, the entry of insects into the through hole 216 is inhibited. Therefore, the possibility of false non-fire alarms or missed detection of fires caused by the entry of insects as described above can be reduced.

[0085] Next, the function of forming the hook 1091 on the antenna holding portion 109 of the main body base plate 1 will be described with reference to Fig. 26. Fig. 26 referred to in this description is a cross-sectional view taken along line E-E of Fig. 3. In Fig. 26, hatching is omitted to prevent the drawing from being difficult to view.

[0086] As shown in the figure, a cutout hole 112 is formed directly above the hook 1091. This cutout hole 112 is a hole formed when the main body base plate 1 is die-molded. If an insect enters this cutout hole 112, the insect may reach the space between the upper surface of the main body cover 5 and the lower surface of the middle plate 4 through the space between the inner peripheral surface of the main body cover 5 and the outer peripheral surface of the middle plate 4 as shown by the arrow A1 in the figure. However, even if it reaches that space, it is blocked by the insect-proof net ring 6 and cannot enter the smoke detection space.

[0087] On the other hand, assume a case where a hook is formed on the cylindrical wall 103 instead of the antenna holding part 109. More specifically, assume a main body base plate 1A in which a hook 1037 is formed on the cylindrical wall 103. FIG. 27 is a bottom view of this main body base plate 1A. In the main body base plate 1A shown in the figure, a hook 1037 is formed on the outer surface of the wall part 1032 that constitutes the cylindrical wall 103.

[0088] Assume a case where a locking hole is formed in the partition wall 426 instead of the side wall 421 of the middle plate 4 along with this change in the position of the hook. More specifically, assume a middle plate 4A in which a locking hole 4261 is formed in the partition wall 426. FIG. 28 is an upper surface perspective view of this middle plate 4A. In the middle plate 4A shown in the figure, a locking hole 4261 is formed in the central part of the partition wall 426. The hook 1037 is locked in this locking hole 4261.

[0089] Assume a case where the main body base plate 1A and the middle plate 4A described above are replaced with the main body base plate 1 and the middle plate 4. More specifically, assume a smoke detector 100A including the main body base plate 1A and the middle plate 4A. FIG. 29 is a longitudinal sectional view of this smoke detector 100A. In this FIG. 29, hatching is omitted to prevent the drawing from being difficult to view.

[0090] In the smoke detector 100A shown in the figure, a cutout hole 113 is formed directly above the hook 1037. This cutout hole 113 is a hole formed when the main body base plate 1A is die-molded. If an insect enters this cutout hole 113, the insect may pass between the partition wall 426 and the side wall 421 of the middle plate 4A as shown by the arrow A2 in the figure, and enter the insect-proof net ring 6 through the cutout hole 429 formed under the locking hole 4261. If it enters the insect-proof net ring 6, the insect may pass between the labyrinth walls 403 to 405, pass through the ventilation hole 402, and enter the smoke detection space. If it enters the smoke detection space, the light of the light emitting part 205 may hit the insect and scatter, and may be received by the light receiving part 206. If the scattered light is received by the light receiving part 206, a fire may be detected even though no fire has actually occurred. As another possibility, it is conceivable that it enters the light emitting part accommodation space from the smoke detection space through the light passage hole 1035. If it enters the light emitting part accommodation space, the light emission of the light emitting part 205 may be blocked by the insect, and it may not be possible to detect the fire even if a fire occurs. As yet another possibility, it is conceivable that it enters the light receiving part accommodation space from the smoke detection space through the light passage hole 1036. If it enters the light receiving part accommodation space, the light reception of the light receiving part 206 may be blocked by the insect, and it may not be possible to detect the fire even if a fire occurs.

[0091] On the other hand, if a hook 1091 is formed on the antenna holding part 109, the cutout hole 112 directly above it will be located outside the insect-proof net ring 6 in a side view (see Fig. 26). Therefore, even if an insect enters the cutout hole 112, it will be difficult for the insect to enter the insect-proof net ring 6. Accordingly, the possibility of false alarms or missed fire detections due to the intrusion of insects as described above is reduced.

[0092] 1-7. Operation Next, the operation of the smoke detector 100 will be described. Specifically, the fire detection process, the fire signal transfer process, and the wireless channel setting process will be described.

[0093] First, the fire detection process will be described. When a fire breaks out in the monitoring area of the smoke detector 100, the smoke from the fire rises towards the ceiling. Then, upon reaching the ceiling, it flows horizontally along the ceiling surface. When the smoke flows in through the ventilation holes 502 of the smoke detector 100, the inflowing smoke passes through the insect screen ring 6 and enters the smoke detection space through the ventilation holes 402 of the middle plate 4. When it enters the smoke detection space, the light from the light emitting part 205 hits the smoke particles and scatters, and is received by the light receiving part 206. When the light receiving part 206 receives the scattered light, it outputs a detection signal to the control circuit 214. When the control circuit 214 receives this detection signal, it causes the speaker 3 to emit an alarm sound and causes the wireless communication circuit 215 to transmit a fire signal to other smoke detectors 100 and relay devices. The above is the explanation of the fire detection process.

[0094] Next, the fire signal transfer process will be described. When the control circuit 214 of the smoke detector 100 receives a fire signal from another smoke detector 100, it causes the speaker 3 to emit an alarm sound. In addition, the control circuit 214 causes the wireless communication circuit 215 to transmit a fire signal to yet another smoke detector 100 or relay device. This enables interlocking between the smoke detectors 100.

[0095] Next, the wireless channel setting process will be described. When the registration switch 209 of the smoke detector 100 is long-pressed by the user, the control circuit 214 starts the wireless channel setting mode. In this wireless channel setting mode, the control circuit 214 changes the wireless channel each time the registration switch 209 is short-pressed. In addition, each time the wireless channel is changed, the speaker 3 emits a guide voice notifying the number of the wireless channel. When the registration switch 209 is long-pressed again, the control circuit 214 stores the number of the selected wireless channel and ends the wireless channel setting mode.

[0096] After that, when the erase switch 210 is long-pressed by the user, the control circuit 214 erases the stored wireless channel number.

[0097] 2. Modification Example The above embodiment may be modified as follows. Note that the following modification examples may be combined with each other.

[0098] 2-1. Modification Example 1 The shape of the main body base plate 1 shown in FIG. 6 and the like is merely an example. The shape of the main body base plate 1 may be appropriately changed according to the shapes of the battery, the substrate 2, and the speaker 3 mounted on the smoke detector 100, the types of electronic components mounted on the substrate 2, and the like.

[0099] 2-2. Modification Example 2 The cylindrical wall 103 of the main body base plate 1 has a trapezoid shape with equal legs as shown in FIG. 6. However, this shape is merely an example, and instead of the trapezoid shape with equal legs, for example, it may have a triangular shape.

[0100] 2-3. Modification Example 3 The rib 104 of the main body base plate 1 has a substantially U-shaped shape as shown in FIG. 6. However, this shape is merely an example, and instead of the substantially U-shaped shape, for example, it may have a semi-circular shape.

[0101] As described above, the rib 104 abuts on the substrate 2. However, it is not essential to bring the rib 104 into contact with the substrate 2. A slight gap may be provided between the rib 104 and the substrate 2 without bringing them into contact. However, the size of the gap should be such that it inhibits the passage of insects. Specifically, for example, it may be substantially the same as the mesh size of the insect-proof net ring 6.

[0102] 2-4. Modification Example 4 The rib 105 of the main body base plate 1 has a U-shaped shape as shown in FIG. 6. However, this shape is merely an example, and instead of the U-shaped shape, for example, it may have a semi-circular shape.

[0103] As described above, there is a slight gap between the rib 105 and the substrate 2. However, this gap is not essential. The rib 105 may be brought into contact with the substrate 2 without leaving a gap therebetween.

[0104] 2-5. Modification Example 5 The shape of the substrate 2 shown in FIG. 9 and the like is merely an example. The shape of the substrate 2 may be appropriately changed according to the shape of the battery and the speaker 3 mounted on the smoke detector 100, the shape of the cylindrical wall 103 of the main body base plate 1, and the like.

[0105] 2-6. Modification Example 6 As described above, the notch 202 of the substrate 2 abuts on the outer surface of the cylindrical wall 103 of the main body base plate 1. However, it is not essential to bring the notch 202 into contact with the outer surface of the cylindrical wall 103. The notch 202 may be brought close to the outer surface of the cylindrical wall 103 with a slight gap therebetween. However, the gap at that time shall be sized to prevent insects from passing through. Specifically, for example, it may be substantially the same as the mesh size of the insect-proof net ring 6.

[0106] A pair of notches 203 and 204 of the substrate 2 have a rectangular shape as shown in FIG. 14. However, this shape is merely an example, and instead of the rectangular shape, for example, it may have a semi-circular shape.

[0107] 2-7. Modification Example 7 The shape of the middle plate 4 shown in FIG. 15 and the like is merely an example. The shape of the middle plate 4 may be appropriately changed according to the shape of the battery, the substrate 2 and the speaker 3 mounted on the smoke detector 100, the types of electronic components mounted on the substrate 2, and the like.

[0108] 2-8. Modification Example 8 The U-shaped portion 4272 of the rib 427 of the middle plate 4 has a U-shaped shape as shown in FIG. 22. However, this shape is merely an example, and instead of the U-shaped shape, for example, it may have a semi-circular shape.

[0109] As described above, there is a slight gap between the rib 427 and the substrate 2. However, this gap is not essential. The rib 427 may be brought into contact with the substrate 2 without leaving a gap therebetween.

[0110] 2-9. Modification Example 9 The U-shaped portion 4282 of the rib 428 of the middle plate 4 has a U-shaped configuration as shown in FIG. 22. However, this configuration is merely an example, and instead of the U-shaped configuration, for example, it may have a semi-circular configuration.

[0111] As described above, a slight gap exists between the rib 428 and the substrate 2. However, this gap is not essential. The rib 428 may be brought into contact with the substrate 2 without leaving a gap therebetween.

[0112] 2-10. Modification Example 10 The insect screen ring 6 has a cylindrical configuration as shown in FIG. 4. However, this configuration is merely an example, and instead of the cylindrical configuration, for example, it may have an elliptical cylindrical configuration or a rectangular cylindrical configuration.

[0113] 2-11. Modification Example 11 The smoke detector 100 includes ribs 105 (see FIG. 6) of the main body base plate 1 and a pair of ribs 427 and 428 (see FIG. 17) of the middle plate 4 in order to reduce the possibility of false alarms or missed detections of fires caused by the intrusion of insects. However, it is not essential for the smoke detector 100 to include all of those ribs. Instead, the smoke detector 100 may be provided with only one or two of those ribs.

Description of Reference Numerals

[0114] 1…Body base plate, 2…Substrate, 3…Speaker, 4…Middle plate, 5…Body cover, 6…Insect-proof net ring, 7…Optical bench cover, 8…Illumination switch, 100…Smoke detector, 101…Battery housing part, 102…Speaker housing part, 103…Cylindrical wall, 104…Rib, 105…Rib, 106…Substrate mounting part, 107A, 107B…Pushing part, 108, 109…Antenna holding part, 110, 111…Switch holding part, 201…Notch, 202…Notch, 203…Notch, 204…Notch, 205…Light emitting part, 206…Light receiving part, 207…Inspection switch, 208…Confirmation lamp, 209…Registration switch, 210…Erase switch, 211…Connector, 212…Antenna, 213…Conductor, 214…Control circuit, 215…Wireless communication circuit, 216…Through hole, 217…Through hole, 401…Notch, 402…Vent hole, 403~405…Labyrinth wall, 406, 407…Locking hole, 408~415…Antenna holding part, 416…Insertion hole, 417…Speaker hole, 418…Switch hole, 419…Display hole, 420…Antenna hole, 421…Side wall, 422~425…Locking hole, 426…Partition wall, 427, 428…Rib, 501…Switch hole, 502…Vent hole, 503A, 503B…Switch support part, 1031~1034…Wall part, 1035, 1036…Light passing hole, 2121…Straight part, 2122…Arc part, 2131…Straight part, 2132…Arc part

Claims

【Claim 1】 a main body base plate, and a substrate are provided, wherein the main body base plate has a wall portion forming a smoke detection space, and a rib that protrudes toward the substrate, is connected to an outer surface of the wall portion, and forms a light receiving portion accommodation space or a light emitting portion accommodation space between the rib and the wall portion ; the substrate abuts on or is close to the wall portion and covers the light receiving portion accommodation space or the light emitting portion accommodation space, and a gap between the rib and the substrate has a size that inhibits passage of insects characterizing the smoke detector.

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