Smoke sensor

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 technology]

[0002] Conventionally, a scattered light type smoke detector has been known (see, for example, Patent Document 1). A scattered light type smoke detector generally comprises a dark box and a pair of a light emitting element and a light receiving element, and detects a fire when the light from the light emitting element is scattered by smoke that has flowed into the dark box and the scattered light is received by the light receiving element. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-175501 Summary of the Invention [Problem to be solved by the invention]

[0004] Insects such as spiders may invade such smoke detectors. If an insect invades a smoke detector and enters the dark box, the insect may scatter the light from the light-emitting element, and the scattered light may be received by the light-receiving element. If the light-receiving element receives the light, a fire may be detected even though there is no actual fire. Another possibility is that the invading insect may interfere with the light-emitting element's emission or the light-receiving element's reception of light, resulting in the detector failing to detect a fire even though there is actually a fire.

[0005] The present invention has been made in view of the above circumstances, and aims to reduce the possibility of false fire alarms or missed fire detections due to insect intrusion. [Means for solving the problem]

[0006] In order to solve the above problems, the smoke detector of the present invention comprises a main body base plate and a substrate arranged below the main body base plate and approximately parallel to the main body base plate, the main body base plate having a cylindrical wall provided on the underside of the main body base plate and forming a smoke detection space, and a first rib having both ends connected to the outer surface of a first wall portion constituting the cylindrical wall and forming a light receiving unit accommodating space between the first wall portion and the first rib extending from the underside of the main body base plate toward the substrate to prevent insects from entering the light receiving unit accommodating space, the substrate having an end abutting or close to the outer surface of the first wall portion and covering the light receiving unit accommodating space, and the substrate is equipped on its upper surface with a light emitting unit that irradiates light into the smoke detection space, and a light receiving unit that is accommodated in the light receiving unit accommodating space and receives light irradiated from the light emitting unit and scattered by smoke particles through a first light passing hole formed in the first wall portion. [Effects of the Invention]

[0007] According to the present invention, it is possible to reduce the possibility of false fire alarms or missed fire detections due to insect intrusion. [Brief explanation of the drawings]

[0008] [Figure 1] Bottom view of smoke detector 100 [Figure 2] Side view of smoke detector 100 [Figure 3] Plan view of smoke detector 100 [Figure 4] An exploded perspective view of the smoke detector 100. [Figure 5] Cross section of line AA in Figure 3 [Figure 6] Bottom view of main body base plate 1 [Figure 7] A perspective view of the bottom of the main body base plate 1 [Figure 8] A perspective view of the bottom of the main body base plate 1 [Figure 9] Bottom view of board 2 [Figure 10] Plan view of substrate 2 [Figure 11] A perspective view of the bottom of the substrate 2 [Figure 12]Bottom view of the circuit board 2 and speaker 3 attached to the main body base plate 1 [Figure 13] A side view of the circuit board 2 and speaker 3 attached to the main body base plate 1. [Figure 14] Enlarged view of part B in Figure 12 [Figure 15] Bottom view of middle plate 4 [Figure 16] Underside perspective view of the middle plate 4 [Figure 17] Plan view of middle plate 4 [Figure 18] Plan perspective view of the middle plate 4 [Figure 19] Bottom view of the middle plate 4 attached to the main body base plate 1 [Figure 20] Side view of the middle plate 4 attached to the main body base plate 1 [Figure 21] Cross section of line CC in Figure 20 [Figure 22] Enlarged view of part D in Figure 21 [Figure 23] Bottom view of main body cover 5 [Figure 24] Side view of main body cover 5 [Figure 25] Plan view of the main body cover 5 [Figure 26] Cross section of Figure 3 taken along line EE [Figure 27] Bottom view of main body base plate 1A [Figure 28] Top perspective view of middle plate 4A [Figure 29] Vertical cross section of smoke detector 100A DETAILED DESCRIPTION OF THE INVENTION

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

[0010] 4 and 5, smoke detector 100 is composed of a circular main body base plate 1, a substantially L-shaped substrate 2 and a circular speaker 3 arranged substantially parallel to each other below main body base plate 1, a substantially circular middle plate 4 arranged substantially parallel to each other below substrate 2, and a cylindrical main body cover 5 with a bottom that houses main body base plate 1, substrate 2, speaker 3, and middle plate 4 and is fixed to main body base plate 1. Each of the components of smoke detector 100 will be described below in order.

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

[0012] As shown in these figures, the main body base plate 1 has a battery housing section 101 formed from its center to its periphery. This battery housing section 101 is convex on the underside of the main body base plate 1 and concave on the upper side, and a cylindrical battery is housed in the recess on the upper side. The battery housed in this battery housing section 101 is connected to the board 2 and supplies power to the circuit on the board 2.

[0013] The main body base plate 1 also has a speaker housing portion 102 formed adjacent to the battery housing portion 101. This speaker housing portion 102 is a substantially C-shaped rib that protrudes vertically from the underside of the main body base plate 1. The speaker 3 is housed in this speaker housing portion 102.

[0014] The speaker enclosure 102 has a hook 1021 on its outer circumferential surface. The hook 1021 is engaged with an engaging hole 422 (see FIG. 18) of the intermediate plate 4, which will be described later.

[0015] The main body base plate 1 also has a cylindrical wall 103 formed on the axis of the battery housed in the battery housing section 101. This cylindrical wall 103 is an isosceles trapezoidal rib that protrudes vertically from the lower surface of the main body base plate 1. The lower end of this cylindrical wall 103 abuts against the upper surface of the middle plate 4, forming a smoke detection space.

[0016] The cylindrical wall 103 is composed of four linear wall portions 1031, 1032, 1033, and 1034. Of these, the wall portion 1033 has a light passing hole 1035 through which the light emitting portion 205 (described later) irradiates light into the smoke detection space. The wall portion 1034 has a light passing hole 1036 through which the light receiving portion 206 (described later) receives light from the smoke detection space.

[0017] The main body base plate 1 also has a generally U-shaped rib 104 with both ends connected to the outer surface of the wall portion 1033. The rib 104 forms a light emitting portion accommodating space between itself and the wall portion 1033.

[0018] The rib 104 extends vertically from the lower surface of the main body base plate 1 toward the substrate 2 and abuts against the upper surface of the substrate 2 so as to prevent insects from entering the light emitting unit housing space.

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

[0020] The ribs 105 extend vertically from the underside of the main body base plate 1 toward the substrate 2 so as to prevent insects from entering the light receiving unit housing space. There is a small gap between the ribs 105 and the substrate 2, but this gap is approximately the same size as the mesh of the insect screen ring 6 (see FIG. 4), which will be described later. In other words, it is of a size that prevents insects from passing through.

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

[0022] The board mounting portion 106 has two hooks 1061 and 1062 on its outer surface. The two hooks 1061 and 1062 are respectively engaged with engaging holes 423 and 424 (see FIG. 18) of the middle plate 4, which will be described later.

[0023] The main body base plate 1 also has two push-in sections 107A and 107B formed on the opposite side of the battery housing section 101 from the speaker housing section 102. These two push-in sections 107A and 107B are rod-shaped members, and are formed by forming U-shaped through grooves in the main body base plate 1.

[0024] Of the two pressing portions 107A and 107B, pressing portion 107A is arranged so as to come into contact with registration switch 209, which will be described later, and when this pressing portion 107A is pressed by a user, registration switch 209 is pressed. On the other hand, pressing portion 107B is arranged so as to come into contact with erase switch 210, which will be described later, and when this pressing portion 107B is pressed by a user, erase switch 210 is pressed.

[0025] Main body base plate 1 also has two pillar-shaped antenna holding portions 108 and 109 that protrude vertically from its peripheral edge. Of these two antenna holding portions 108 and 109, antenna holding portion 108 is disposed adjacent to the outer surface of board mounting portion 106. Antenna holding portion 108 is inserted into insertion hole 416 (see FIG. 15 ) of middle plate 4, which will be described later. Antenna holding portion 108 also has a U-shaped groove formed at its tip, into which antenna 212 is fitted.

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

[0027] The antenna holding portion 109 also has a hook 1091 on its outer surface (in other words, the surface opposite to the surface facing the cylindrical wall 103). The hook 1091 is engaged with an engaging hole 425 (see FIG. 15) of the middle plate 4, which will be described later.

[0028] The main body base plate 1 also has a pair of plate-like switch holders 110 and 111 that protrude vertically from the periphery of the main body base plate 1. The pair of switch holders 110 and 111 hold an illuminated switch 8, which will be described later.

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

[0030] 1-3.Configuration of board 2 Next, the substrate 2 will be described with reference to Figures 9 to 11. Figures 9 to 11, which will be 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 sector-shaped cutout 201 with a central angle of approximately a right angle. The battery holder 101 of the main body base plate 1 and the speaker 3 are arranged in the area where this cutout 201 is formed. The speaker 3 arranged in this area is connected to the substrate 2.

[0032] The substrate 2 also has an isosceles trapezoidal cutout 202. The cylindrical wall 103 of the main body base plate 1 is disposed in the area where the cutout 202 is formed.

[0033] The substrate 2 also has a pair of rectangular cutouts 203 and 204 that face each other with an isosceles trapezoidal cutout 202 sandwiched therebetween.

[0034] 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 housing space formed by the cylindrical wall 103 and ribs 104 of the main body base plate 1, and irradiates light into the smoke detection space formed by the cylindrical wall 103. At this time, the light-emitting unit 205 irradiates light into the smoke detection space through a light passing hole 1035 in the cylindrical wall 103.

[0035] 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 housing space formed by the cylindrical wall 103 and ribs 105 of the main body base plate 1, and receives light from the light emitting unit 205 that is scattered by smoke particles. At this time, the light receiving unit 206 receives the scattered light through the light passing hole 1036 in the cylindrical wall 103.

[0036] The light emitting section 205 and the light receiving section 206 are arranged along the isosceles trapezoidal cutout 202 so that their optical axes are not aligned on the same straight line.

[0037] Additionally, an inspection switch 207 and a confirmation light 208 are mounted on the underside of the board 2. Of these, the inspection switch 207 is a switch used to test the internal circuitry and battery life. This inspection switch 207 is designed to be pressed down when the illuminated switch 8, which will be described later, is pressed. On the other hand, the confirmation light 208 is an LED that notifies the results of the test.

[0038] In addition, a registration switch 209 and a deletion switch 210 are mounted on the top 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 wireless channel setting.

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

[0040] In addition, 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 the 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 cutout portion 202.

[0041] A conductor 213 made of a metal wire is also 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 holding 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 to surround the speaker 3.

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

[0043] Furthermore, a wireless communication circuit 215 (not shown) is mounted on the board 2. This wireless communication circuit 215 uses an antenna 212 to perform wireless communication with other smoke detectors 100 and relay devices. The above is the explanation of the substrate 2.

[0044] The peripheral portion of the upper surface of the substrate 2 described above is attached to the substrate attachment portion 106 of the main body base plate 1. The speaker 3 connected to the substrate 2 is fitted into the speaker housing portion 102 of the main body base plate 1. Figures 12 and 13 are bottom and side views of the substrate 2 and speaker 3 attached to the main body base plate 1 in this manner. Figure 14 is an enlarged view of portion B in Figure 12.

[0045] 12 among these figures, the battery accommodating section 101 of the main body base plate 1 is disposed in the region where the fan-shaped cutout 201 of the substrate 2 is formed. The cylindrical wall 103 of the main body base plate 1 is disposed in the region where the isosceles trapezoidal cutout 202 of the substrate 2 is formed. The cutout 202 of the substrate 2 abuts against the outer surface of the cylindrical wall 103.

[0046] More specifically, as shown in FIG. 14 , the cutout 202 abuts against the outer surfaces of the walls 1031, 1033, and 1034 out of the four walls 1031 to 1034 that constitute the cylindrical wall 103. Therefore, the substrate 2 covers the light-emitting unit accommodating space and the light-receiving unit accommodating space formed in the main body base plate 1. The rectangular cutout 203 of the substrate 2 forms a through-hole 216 between the wall 1033 and the rectangular cutout 203. This through-hole 216 is a through-hole that connects the space between the substrate 2 and the middle plate 4 to the light-emitting unit accommodating space. The rectangular cutout 204 of the substrate 2 forms a through-hole 217 between the wall 1034 and the rectangular cutout 204. This through-hole 217 is a through-hole that connects the space between the substrate 2 and the middle plate 4 to the light-receiving unit accommodating space.

[0047] In addition, as shown in Figure 12, the antenna 212 connected to the substrate 2 is clamped between the antenna holding portions 108 and 109 of the main body base plate 1 and a U-shaped groove formed at the tip of the switch holding portion 110.

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

[0049] As shown in these figures, the middle plate 4 has a generally U-shaped notch 401 formed from the center to the periphery thereof. The battery housing section 101 of the main body base plate 1 is disposed in the area where this notch 401 is formed.

[0050] The middle plate 4 also has an oval ventilation hole 402 formed on the opposite side of the center from the notch 401. This ventilation hole 402 is a ventilation hole that connects 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] The middle plate 4 also has three labyrinth walls 403-405 formed around the vent hole 402. These three labyrinth walls 403-405 are plate-like walls that protrude vertically from the lower surface of the middle plate 4. These three labyrinth walls 403-405 are formed so as not to impede the inflow of smoke into the vent hole 402, but to prevent external light from entering the vent hole 402.

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

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

[0054] The middle plate 4 also has a rectangular insertion hole 416 formed in its peripheral portion. The antenna holding portion 108 of the main body base plate 1 is inserted into this insertion hole 416.

[0055] The middle plate 4 also has a plurality of speaker holes 417 formed adjacent to the U-shaped cutout 401. The plurality of speaker holes 417 are arranged below the speaker 3.

[0056] The middle plate 4 also has a switch hole 418 and an indicator hole 419 formed adjacent to the U-shaped cutout 401. Of these holes, the switch hole 418 is an insertion hole through which the inspection switch 207 is inserted. On the other hand, the indicator hole 419 is a light passing hole through which light from the confirmation light 208 passes.

[0057] The middle plate 4 also has an antenna hole 420 formed in its peripheral edge portion. This antenna hole 420 is an insertion hole through which the antenna 212 is inserted.

[0058] The middle plate 4 also has a side wall 421 standing on the periphery of its upper surface.

[0059] The middle plate 4 also has three rectangular locking holes 422 to 424 formed in the side wall 421. Of 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] The middle plate 4 also 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 configured by connecting a rectangular hole formed in the peripheral edge and a rectangular hole formed in the side wall 421. Of these holes, the antenna holding part 109 of the main body base plate 1 is inserted into the former hole. Meanwhile, a hook 1091 of the main body base plate 1 is engaged in the latter hole.

[0061] The middle plate 4 also has a partition wall 426 that separates the vent hole 402 and the locking hole 425, and both ends of the partition wall 426 are connected to the side walls 421. The partition wall 426 is a plate that protrudes vertically from the upper surface of the middle plate 4.

[0062] The middle plate 4 also has a pair of ribs 427 and 428 formed to surround the ventilation hole 402 together with the partition wall 426. The pair of ribs 427 and 428 are formed to extend substantially perpendicularly from the upper surface of the middle plate 4 toward the base plate 2. There is a small gap between the pair of ribs 427 and 428 and the base plate 2, but this gap is approximately the same size as the mesh size of the insect screen ring 6 (see FIG. 4), which will be described later. In other words, it is of a size that prevents insects from passing through.

[0063] Of the pair of ribs 427 and 428, rib 427 is composed of a straight portion 4271 having one end connected to partition wall 426, a U-shaped portion 4272 having one end connected to the other end of straight portion 4271, and a straight portion 4273 having one end connected to the other end of U-shaped portion 4272. On the other hand, rib 428 is composed of a straight portion 4281 having one end connected to partition wall 426, and a U-shaped portion 4282 having one end connected to the other end of straight portion 4281. The lower end of cylindrical wall 103 of main body base plate 1 is fitted into the space formed by this pair of ribs 427 and 428 and partition wall 426. The above is an explanation 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 circuit board 2 and the speaker 3. At this time, hooks 1021, 1061, 1062, and 1091 of the main body base plate 1 are engaged with engagement holes 422 to 425 of the middle plate 4, thereby fixing the middle plate 4 to the main body base plate 1. 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 manner. FIG. 21 is a cross-sectional view taken along line CC in FIG. 20. FIG. 22 is an enlarged view of part D in FIG. 21.

[0065] As shown in these figures, particularly in FIG. 19, the battery housing section 101 of the main body base plate 1 is disposed in the area where the cutout section 401 of the middle plate 4 is formed. The antenna holder 108 of the main body base plate 1 is inserted into the insertion hole 416 of the middle plate 4. The antenna holder 109 of the main body base plate 1 is inserted into the locking hole 425 of the middle plate 4. The antenna 212 is inserted into the antenna hole 420 of the middle plate 4. The antenna 212 inserted into the antenna hole 420 is fitted into the cutout sections of the antenna holders 408 to 415 of the middle plate 4. The inspection switch 207 is inserted into the switch hole 418 of the middle plate 4. The confirmation light 208 can be seen through the indicator hole 419 of the middle plate 4.

[0066] 22 , the lower end of the cylindrical wall 103 of the main body base plate 1 is fitted into the space formed by the partition 426 of the middle plate 4 and the pair of ribs 427 and 428. As a result, the partition 426 of the middle plate 4 abuts against the outer surfaces of the wall portions 1032 to 1034 that constitute the cylindrical wall 103. The rib 427 of the middle plate 4 abuts against the outer surfaces of the wall portions 1031 and 1034 that constitute the cylindrical wall 103. In particular, the U-shaped portion 4272 of the rib 427 abuts at both ends against the outer surface of the wall portion 1034, surrounding the through-hole 217. In addition, the upper end of this U-shaped portion 4272 is close enough to the base plate 2 to prevent insects from passing through. Therefore, this U-shaped portion 4272 prevents insects from entering the through-hole 217 in the space between the middle plate 4 and the base plate 2.

[0067] Furthermore, the rib 428 of the middle plate 4 abuts against the outer surface of the wall portion 1033 that constitutes the cylindrical wall 103. In particular, the U-shaped portion 4282 of the rib 428 has both ends abutting against the outer surface of the wall portion 1033, surrounding the through-hole 216. In addition, the upper end of this U-shaped portion 4282 is close enough to the base plate 2 to prevent insects from passing through. Therefore, this U-shaped portion 4282 prevents insects from entering the through-hole 216 in the space between the middle plate 4 and the base plate 2.

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

[0069] 23 among these figures, the main body cover 5 has an oval switch hole 501 formed in the bottom plate thereof. The lighted switch 8 (see FIG. 4) is fitted into this switch hole 501.

[0070] 24, the main body cover 5 has a plurality of ventilation holes 502 formed on the underside 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] 25, the body cover 5 has a pair of switch support portions 503A and 503B formed adjacent to the switch hole 501. The pair of switch support portions 503A and 503B have U-shaped notches into which the shaft of the illuminated switch 8 is fitted. The above is the description of the main body cover 5.

[0072] The body cover 5 described above is fixed to the body base plate 1 while housing the body base plate 1, circuit board 2, speaker 3, and middle plate 4 (see FIG. 4). At this time, an insect screen ring 6 is attached to the middle plate 4 housed in the body cover 5. More specifically, the insect screen ring 6 is attached so as to surround the ventilation hole 402 and labyrinth walls 403 to 405 of the middle plate 4.

[0073] Then, an optical base cover 7 is attached so as to cover the lower opening of the attached insect screen ring 6. This optical base cover 7 has a disk portion, a star-shaped protrusion formed in the center of the upper surface of the disk portion, and a pair of hooks erected on the periphery of the disk portion. When this optical base cover 7 is attached to the middle plate 4, the disk portion covers the lower opening of the insect screen ring 6, the protrusions are inserted between the labyrinth walls 403-405 of the middle plate 4, and the pair of hooks are engaged with a pair of engagement holes 406 and 407 of the middle plate 4.

[0074] In addition, an illuminated switch 8 is attached to the main body base plate 1 housed in the main body cover 5. The illuminated switch 8 has an oval plate portion, a protruding portion protruding vertically from one end of the plate portion, a column-shaped portion standing vertically on the other end of the plate portion, and a shaft portion formed at the base end of the column-shaped portion. The illuminated switch 8 is made of a translucent resin material containing a light-diffusing agent. When the illuminated switch 8 is attached to the main body base plate 1, the protruding portion abuts against the inspection switch 207 on the circuit board 2, the column-shaped portion is inserted between a pair of switch holders 110 and 111 on the main body base plate 1, and the shaft portion is fitted into the U-shaped groove of the pair of switch holders 110 and 111.

[0075] As explained above, after the insect screen ring 6, optical bench cover 7, and illuminated switch 8 are attached, 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 illuminated switch 8 is fitted into the switch hole 501. In addition, the shaft portion of the illuminated switch 8 is clamped between the pair of switch support portions 503A and 503B of the main body cover 5 and the pair of switch holding portions 110 and 111 of the main body base plate 1.

[0076] 1-6.Effect 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 of this rib 105 is close enough to the substrate 2 to prevent insects from passing through. Therefore, this rib 105 prevents insects from entering the light receiving unit accommodating space formed between the rib and the cylindrical wall 103.

[0077] As described above, the main body base plate 1 has the push-in portions 107A and 107B (see FIG. 6). U-shaped through-grooves are formed around these push-in portions 107A and 107B, and insects may enter the device through these U-shaped through-grooves. If an insect enters the device, it may travel between the main body base plate 1 and the substrate 2 and reach the vicinity of the light receiving unit 206. If the rib 105 were not present, the insect would enter the optical axis of the light receiving unit 206, potentially blocking light reception by the light receiving unit 206. If light reception by the light receiving unit 206 were blocked, the fire would not be detected even if a fire breaks out. Another possibility is that the insect may enter the smoke detection space through the light passing hole 1036. If the insect enters the smoke detection space, the light from the light emitting unit 205 may be scattered by the insect and 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 no actual fire.

[0078] In contrast, the presence of the rib 105 prevents insects from entering the light receiving unit housing space, thereby reducing the possibility of false fire alarms or missed fire detections due to insect intrusion as described above.

[0079] Next, the function of the rib 427 of the middle plate 4 will be described. 22, the rib 427 of the middle plate 4 has a U-shaped portion 4272. This U-shaped portion 4272 is a U-shaped rib whose both ends abut the outer surface of the cylindrical wall 103 and surrounds the through-hole 217. In addition, the upper end of this U-shaped portion 4272 is close enough to the base plate 2 to prevent insects from passing through. Therefore, this U-shaped portion 4272 prevents insects from entering the through-hole 217 in the space between the middle plate 4 and the base plate 2.

[0080] As described above, the main body cover 5 has the ventilation hole 502 (see FIG. 24). Furthermore, as described above, the middle plate 4 has the display hole 419 (see FIG. 15). There is a possibility that insects may enter the space between the middle plate 4 and the base plate 2 through the ventilation hole 502 and the display hole 419. If an insect enters the space, it may move through the space and reach the vicinity of the through-hole 217. If the U-shaped portion 4272 is not present, the insect may enter the light-receiving unit housing space through the through-hole 217. If the insect enters the light-receiving unit housing space, it may interfere with the light-receiving unit 206 receiving light. If the light-receiving unit 206 is prevented from receiving light, the fire may not be detected even if a fire breaks out. Another possibility is that the insect may enter the smoke detection space through the light-passing hole 1036. If an insect enters the smoke detection space, the light from the light-emitting unit 205 may hit the insect, scatter, and be received by the light-receiving unit 206. If the scattered light is received by the light-receiving unit 206, a fire may be detected even though there is no actual fire.

[0081] In contrast to this, the presence of the U-shaped portion 4272 prevents insects from entering the through-hole 217. Therefore, it is possible to reduce the possibility of false fire alarms or missed fire detections due to insect intrusion as described above.

[0082] Next, the function of the rib 428 of the intermediate plate 4 will be described. 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 abut the outer surface of the cylindrical wall 103 and surrounds the through-hole 216. In addition, the upper end of this U-shaped portion 4282 is close enough to the base plate 2 to prevent insects from passing through. Therefore, this U-shaped portion 4282 prevents insects from entering the through-hole 216 in the space between the middle plate 4 and the base plate 2.

[0083] As described above, the main body cover 5 has the ventilation hole 502 (see FIG. 24 ). Furthermore, as described above, the middle plate 4 has the display hole 419 (see FIG. 15 ). There is a possibility that an insect may enter the space between the middle plate 4 and the base plate 2 through the ventilation hole 502 and the display hole 419. If an insect enters the space, it may move through the space and reach the vicinity of the through-hole 216. If the U-shaped portion 4282 were not present, the insect may enter the light-emitting unit housing space through the through-hole 216. If the insect enters the light-emitting unit housing space, it may block the light emission of the light-emitting unit 205. If the light emission of the light-emitting unit 205 is blocked, even if a fire breaks out, the fire cannot be detected. Another possibility is that the insect may enter the smoke detection space through the light-passing hole 1035. If the insect enters the smoke detection space, the light from the light-emitting unit 205 may be scattered by the insect and 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 no actual fire.

[0084] In contrast to this, the presence of the U-shaped portion 4282 prevents insects from entering the through-hole 216. Therefore, it is possible to reduce the possibility of false fire alarms or missed fire detections due to insect intrusion as described above.

[0085] Next, the effect 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 EE in Fig. 3. Note that hatching has been omitted in Fig. 26 to prevent the drawing from becoming difficult to see.

[0086] As shown in the figure, a cut-off hole 112 is formed directly above the hook 1091. This cut-off hole 112 is a hole formed when the main body base plate 1 is molded with a die. If an insect enters this cut-off hole 112, the insect may pass between the inner peripheral surface of the main body cover 5 and the outer peripheral surface of the middle plate 4, as indicated by arrow A1 in the figure, and reach the space between the upper surface of the main body cover 5 and the lower surface of the middle plate 4. However, even if the insect does reach that space, it will be blocked by the insect screen ring 6 and will not be able to enter the smoke detection space.

[0087] In contrast to this, let us assume that a hook is formed on the cylindrical wall 103 instead of the antenna holding portion 109. More specifically, let us assume a main body base plate 1A in which a hook 1037 is formed on the cylindrical wall 103. Figure 27 is a bottom view of this main body base plate 1A. In the main body base plate 1A shown in the figure, the hook 1037 is formed on the outer surface of the wall portion 1032 that constitutes the cylindrical wall 103.

[0088] In accordance with this change in the position of the hook, we will assume that a locking hole is formed in the partition wall 426 instead of the side wall 421 of the middle plate 4. More specifically, we will assume a middle plate 4A in which a locking hole 4261 is formed in the partition wall 426. Figure 28 is a top perspective view of this middle plate 4A. In the middle plate 4A shown in this figure, a locking hole 4261 is formed in the center of the partition wall 426. A hook 1037 is locked in this locking hole 4261.

[0089] Assume that the main body base plate 1A and middle plate 4A described above are replaced with the main body base plate 1 and middle plate 4. More specifically, assume that a smoke detector 100A is provided with the main body base plate 1A and middle plate 4A. Figure 29 is a vertical cross-sectional view of this smoke detector 100A. Note that hatching has been omitted in Figure 29 to avoid making the drawing difficult to read.

[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 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 indicated by arrow A2 in the figure, and then through the cutout hole 429 formed below the locking hole 4261 and enter the insect screen ring 6. If the insect enters the insect screen 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 the insect enters the smoke detection space, the light from the light-emitting element 205 may be scattered by the insect and received by the light-receiving element 206. If the scattered light is received by the light-receiving element 206, a fire may be detected even though no fire actually exists. Another possibility is that insects may enter the light-emitting unit housing space from the smoke detection space through the light passing hole 1035. If they enter the light-emitting unit housing space, they may prevent the light-emitting unit 205 from emitting light, and even if a fire breaks out, the fire may not be detected. Another possibility is that insects may enter the light-receiving unit housing space from the smoke detection space through the light passing hole 1036. If they enter the light-receiving unit housing space, they may prevent the light-receiving unit 206 from receiving light, and even if a fire breaks out, the fire may not be detected.

[0091] In contrast to this, if a hook 1091 is formed on the antenna holding portion 109, the cut-off hole 112 directly above it will be positioned outside the insect screen ring 6 in a side view (see FIG. 26). Therefore, even if an insect does get into the cut-off hole 112, it will be difficult for it to get into the insect screen ring 6. This reduces the possibility of false fire alarms or missed fire detections due to insect intrusion as described above.

[0092] 1-7.Operation Next, a description will be given of the operation of the smoke detector 100. Specifically, a fire detection process, a fire signal transfer process, and a 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 that fire rises toward the ceiling. Once it reaches the ceiling, it flows horizontally along the ceiling surface. When the smoke flows in through the vent 502 of the smoke detector 100, it passes through the insect screen ring 6 and then through the vent 402 in the middle plate 4, and flows into the smoke detection space. When the smoke flows into the smoke detection space, the light from the light-emitting element 205 is scattered by smoke particles and received by the light-receiving element 206. When the light-receiving element 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 and causes the wireless communication circuit 215 to transmit a fire signal to other smoke detectors 100 and relay devices. This concludes the description 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 the fire signal to another smoke detector 100 or a relay device. This allows the smoke detectors 100 to be linked together.

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

[0096] Thereafter, when the user presses and holds the erase switch 210, the control circuit 214 erases the stored wireless channel number.

[0097] 2. Variations The above embodiment may be modified as follows: The following modifications may be combined with each other.

[0098] 2-1. Variation 1 6 and the like is merely an example. The shape of the main body base plate 1 may be changed as appropriate depending on the shapes of the battery, the board 2, and the speaker 3 mounted on the smoke detector 100, the types of electronic components mounted on the board 2, and the like.

[0099] 2-2. Variation 2 The cylindrical wall 103 of the main body base plate 1 has an isosceles trapezoidal shape as shown in Fig. 6. However, this shape is merely an example, and instead of the isosceles trapezoidal shape, it may have, for example, a triangular shape.

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

[0101] As described above, the ribs 104 abut against the substrate 2. However, it is not essential that the ribs 104 abut against the substrate 2. The ribs 104 may not abut against the substrate 2, but may leave a small gap between them. However, the gap should be of a size that prevents insects from passing through. Specifically, for example, the size of the gap may be approximately the same as the mesh size of the insect screen ring 6.

[0102] 2-4. Variation 4 The rib 105 of the main body base plate 1 has a U-shape as shown in Fig. 6. However, this shape is merely an example, and instead of the U-shape, for example, the rib may have a semicircular shape.

[0103] As described above, there is a small 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 between the rib 105 and the substrate 2.

[0104] 2-5. Variation 5 9 and the like is merely an example. The shape of the substrate 2 may be changed as appropriate depending on the shapes of the battery and speaker 3 mounted in the smoke detector 100, the shape of the cylindrical wall 103 of the main body base plate 1, etc.

[0105] 2-6. Variation 6 As described above, the notch 202 of the substrate 2 abuts against the outer surface of the cylindrical wall 103 of the main body base plate 1. However, it is not essential that the notch 202 abut against the outer surface of the cylindrical wall 103. The notch 202 may be located close to the outer surface of the cylindrical wall 103, with a small gap between them, without abutting against it. However, the size of the gap in this case should be such that insects cannot pass through. Specifically, for example, the size of the mesh may be approximately the same as the size of the mesh of the insect screen ring 6.

[0106] The 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 a rectangular shape, for example, they may have a semicircular shape.

[0107] 2-7. Variation 7 15 and the like is merely an example. The shape of the middle plate 4 may be changed as appropriate depending on the shapes of the battery, board 2, and speaker 3 mounted in the smoke detector 100, the types of electronic components mounted on the board 2, and the like.

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

[0109] As described above, there is a small 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 between them.

[0110] 2-9. Variation 9 The U-shaped portion 4282 of the rib 428 of the middle plate 4 has a U-shape as shown in Fig. 22. However, this shape is merely an example, and instead of the U-shape, it may have, for example, a semicircular shape.

[0111] As described above, there is a small gap 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 between them.

[0112] 2-10. Variation 10 The insect screen ring 6 has a cylindrical shape as shown in Fig. 4. However, this shape is merely an example, and instead of a cylindrical shape, it may have, for example, an elliptical cylindrical shape or a square cylindrical shape.

[0113] 2-11. Variation 11 In order to reduce the possibility of false fire alarms or missed fire detections due to insect intrusion, the smoke detector 100 is provided with a rib 105 (see FIG. 6) on the main body base plate 1 and a pair of ribs 427 and 428 (see FIG. 17) on the middle plate 4. However, it is not essential for the smoke detector 100 to have all of these ribs. The smoke detector 100 may be provided with only one or two of these ribs. [Explanation of symbols]

[0114] 1...Main body base plate, 2...Circuit board, 3...Speaker, 4...Middle plate, 5...Main body cover, 6...Insect screen ring, 7...Optical base cover, 8...Illuminated switch, 100...Smoke detector, 101...Battery storage section, 102...Speaker storage section, 103...Cylindrical wall, 104...Rib, 105...Rib, 106...Circuit board mounting section, 107A, 107B...Push-in section, 108, 109...Antenna holding section, 110, 111...Switch holding section, 201...Notch, 202...Notch, 203...Notch, 204...Notch, 205...Light-emitting section, 206...Light-receiving section, 207...Inspection switch, 208...Confirmation light, 209...Registration switch, 210...Delete switch, 211...Connector, 212...Antenna, 213...Conductor Body, 214...control circuit, 215...wireless communication circuit, 216...through hole, 217...through hole, 401...notch, 402...ventilation hole, 403-405...labyrinth wall, 406, 407...locking hole, 408-415...antenna holding portion, 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...ventilation hole, 503A, 503B...switch support portion, 1031-1034...wall portion, 1035, 1036...light passing hole, 2121...straight portion, 2122...circular portion, 2131...straight portion, 2132...circular portion

Claims

[Claim 1] A main body base plate, Substrate and Equipped with The main body base plate is A wall portion that forms a smoke detection space; a rib that protrudes toward the substrate and is connected to an outer surface of the wall portion, and that forms a light receiving unit accommodating space or a light emitting unit accommodating space between the wall portion and the rib; and the substrate abuts on or is close to the wall portion and covers the light receiving unit accommodating space or the light emitting unit accommodating space; The gap between the rib and the substrate has a size that prevents insects from passing through. A smoke detector characterized by:

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