Smoke sensor

Abstract

Reduces the possibility of false alarms or missed fire detections caused by insect intrusion. [Solution] The smoke detector is equipped with a main base plate 1. This main base plate 1 has a cylindrical wall 103 that forms a smoke detection space, and ribs 105 that are connected at both ends to the outer surface of the cylindrical wall 103 and form a light-receiving unit housing space between themselves and the outer surface. A substrate is arranged substantially parallel to the main base plate 1. The ends of this substrate abut against the outer surface and cover the light-receiving unit housing space. The ribs 105 extend from the lower surface of the main base plate 1 toward the substrate to prevent insects from entering the light-receiving unit housing space.

Description

Technical Field

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[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). The 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 enters 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 no fire has actually occurred. As another possibility, it is conceivable that the light emission by the light emitting element or the light reception by the light receiving element is hindered by the entering insect, and a fire cannot be detected even though a fire has actually occurred.

[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 comprises a main base plate and a substrate disposed below the main base plate and substantially parallel to the main base plate, wherein the main base plate has a cylindrical wall provided on the lower surface of the main base plate and forming a smoke detection space, and a first rib whose ends are connected to the outer surface of a first wall portion constituting the cylindrical wall and which forms a light-receiving portion housing space between itself and the first wall portion, and which extends from the lower surface of the main base plate toward the substrate so as to prevent insects from entering the light-receiving portion housing space, wherein the substrate has its ends in contact with or close to the outer surface of the first wall portion and covers the light-receiving portion housing space, and the upper surface of the substrate is equipped with a light-emitting portion that irradiates light into the smoke detection space and a light-receiving portion housed in the light-receiving portion housing space that receives light irradiated from the light-emitting portion 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, the possibility of false fire alarms or missed fire detections due to insect intrusion can be reduced. [Brief explanation of the drawing]

[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] Exploded perspective view of smoke detector 100 [Figure 5] Cross-sectional view of line AA in Figure 3 [Figure 6] Bottom view of the main base plate 1 [Figure 7] Lower perspective view of the main base plate 1 [Figure 8] Lower perspective view of the main base plate 1 [Figure 9] Bottom view of circuit board 2 [Figure 10] Plan view of circuit board 2 [Figure 11] Bottom perspective view of substrate 2 [Figure 12]Bottom view of the substrate 2 and the speaker 3 attached to the main body base plate 1 [Figure 13] Side view of the substrate 2 and the speaker 3 attached to the main body base plate 1 [Figure 14] Enlarged view of part B in FIG. 12 [Figure 15] Bottom view of the middle plate 4 [Figure 16] Bottom perspective view of the middle plate 4 [Figure 17] Plan view of the 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-sectional view taken along line C-C in FIG. 20 [Figure 22] Enlarged view of part D in FIG. 21 [Figure 23] Bottom view of the main body cover 5 [Figure 24] Side view of the main body cover 5 [Figure 25] Plan view of the main body cover 5 [Figure 26] Cross-sectional view taken along line E-E in FIG. 3 [Figure 27] Bottom view of the main body base plate 1A [Figure 28] Top perspective view of the middle plate 4A [Figure 29] Longitudinal sectional view of the smoke detector 100A

Mode for Carrying Out 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] As shown in particular in Figures 4 and 5 of these figures, the smoke detector 100 consists of a circular main base plate 1, a roughly L-shaped circuit board 2 and a circular speaker 3 arranged roughly parallel to the main base plate 1, a roughly circular middle plate 4 arranged roughly parallel to the circuit board 2, and a bottomed cylindrical main cover 5 fixed to the main base plate 1 while housing the main base plate 1, circuit board 2, speaker 3 and middle plate 4. The individual components of this smoke detector 100 will be described in order below.

[0011] 1-2. Configuration of the main base plate 1 First, the main base plate 1 will be explained with reference to Figures 6 to 8. In this explanation, Figure 6 is a bottom view of the main 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 101 formed from its center to its periphery. This battery housing 101 is convex on the lower side of the main body base plate 1 and concave on the upper side, with a cylindrical battery housed in the concave upper side. The battery housed in this battery housing 101 is connected to the circuit board 2 and supplies power to the circuit on the circuit board 2.

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

[0014] The speaker housing 102 has a hook 1021 on its outer surface. This hook 1021 is locked into a locking hole 422 (see Figure 18) of the middle 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 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] This cylindrical wall 103 is composed of four straight wall sections 1031, 1032, 1033, and 1034. Of these, wall section 1033 has a light-passing hole 1035 for the light-emitting section 205 (described later) to irradiate light into the smoke detection space. Wall section 1034 also has a light-passing hole 1036 for the light-receiving section 206 (described later) to receive light from the smoke detection space.

[0017] Furthermore, the main body base plate 1 has a roughly U-shaped rib 104 whose ends are connected to the outer surface of the wall portion 1033. This rib 104 forms a space for housing the light-emitting unit between itself 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, and contacts the upper surface of the substrate 2, in order to prevent insects from entering the space housing the light-emitting part.

[0019] Furthermore, the main body base plate 1 has a U-shaped rib 105 whose ends are connected to the outer surface of the wall portion 1034. This rib 105 forms a light-receiving unit housing space between itself and the wall portion 1034.

[0020] This rib 105 extends vertically from the underside of the main body base plate 1 toward the substrate 2 to prevent insects from entering the light-receiving compartment. There is a small gap between this rib 105 and the substrate 2, but this gap is approximately the same size as the mesh of the insect-proof ring 6 (see Figure 4), which will be described later. In other words, it is a size that prevents insects from passing through.

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

[0022] The substrate mounting portion 106 has two hooks 1061 and 1062 on its outer surface. These two hooks 1061 and 1062 are locked into locking holes 423 and 424 (see Figure 18) of the intermediate 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 speaker housing 102, with the battery housing 101 in between. These two push-in sections 107A and 107B are rod-shaped members and are formed by creating U-shaped through grooves in the main body base plate 1.

[0024] Of these two push-in parts 107A and 107B, push-in part 107A is positioned to contact the registration switch 209, which will be described later, and when push-in part 107A is pressed by the user, the registration switch 209 is pressed down. On the other hand, push-in part 107B is positioned to contact the erase switch 210, which will be described later, and when push-in part 107B is pressed by the user, the erase switch 210 is pressed down.

[0025] The main base plate 1 also has two columnar antenna holding portions 108 and 109 that protrude vertically from its periphery. Of these two antenna holding portions 108 and 109, antenna holding portion 108 is positioned adjacent to the outer surface of the substrate mounting portion 106. This antenna holding portion 108 is inserted into the insertion hole 416 (see Figure 15) of the middle plate 4, which will be described later. Furthermore, a U-shaped groove is formed at the tip of this antenna holding portion 108, into which the antenna 212 is fitted.

[0026] On the other hand, the antenna holder 109 is positioned on the axis of the battery housed in the battery housing 101. This antenna holder 109 is inserted through a locking hole 425 (see Figure 15) in the middle plate 4, which will be described later. Furthermore, a U-shaped groove is formed at the tip of this antenna holder 109, into which the antenna 212 is fitted.

[0027] Furthermore, the antenna holder 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 into a locking hole 425 (see Figure 15) of the intermediate plate 4, which will be described later.

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

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

[0030] 1-3. Configuration of Circuit Board 2 Next, the substrate 2 will be described with reference to Figures 9 to 11. Figures 9 to 11, which will be referenced in this description, are the bottom view, top view, and 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 right angle. The battery housing 101 of the main base plate 1 and the speaker 3 are arranged in the region where this notch 201 is formed. The speaker 3 arranged in this region is connected to the substrate 2.

[0032] The substrate 2 also has an isosceles trapezoidal notch 202. The cylindrical wall 103 of the main base plate 1 is positioned in the region where this notch 202 is formed.

[0033] The substrate 2 also has a pair of rectangular notches 203 and 204 that face each other, with an isosceles trapezoidal notch 202 in between.

[0034] Furthermore, 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 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-passing holes 1035 of the cylindrical wall 103.

[0035] Furthermore, 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 base plate 1, and receives light from the light-emitting unit 205 that has been scattered upon contact with smoke particles. At that time, the light-receiving unit 206 receives the scattered light through the light-passing holes 1036 of the cylindrical wall 103.

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

[0037] Furthermore, a test switch 207 and an indicator light 208 are mounted on the underside of circuit board 2. The test switch 207 is used to test the internal circuitry and battery life. This test switch 207 is pressed when the illumination switch 8, which will be described later, is pressed. The indicator light 208, on the other hand, is an LED that notifies the results of the test.

[0038] Additionally, a registration switch 209 and an erase switch 210 are mounted on the top surface of circuit board 2. The registration switch 209 is used to set the wireless channel used by the smoke detector 100, and the erase switch 210 is used to erase the wireless channel setting.

[0039] Additionally, a connector 211 is mounted on the top surface of circuit board 2.

[0040] An antenna 212 made of metal wire is also 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 bottom surface of the substrate 2, and is inserted into the antenna hole 420 (see Figure 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 202.

[0041] A conductor 213 made of metal wire is connected to the circuit board 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 the ground (not shown) on the circuit board 2 and extends along the longitudinal direction of the battery housing 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] The circuit board 2 also has a control circuit 214 (not shown) mounted on it. This control circuit 214 performs fire detection processing, fire signal transmission processing, and wireless channel setting processing, which will be described later.

[0043] The circuit board 2 also has a wireless communication circuit 215 (not shown) mounted on it. This wireless communication circuit 215 uses an antenna 212 to communicate wirelessly with other smoke detectors 100 and relay devices. The above is a description of circuit board 2.

[0044] The circuit board 2 described above has its upper edge attached to the circuit board mounting portion 106 of the main base plate 1. The speaker 3 connected to the circuit board 2 is fitted into the speaker housing portion 102 of the main base plate 1. Figures 12 and 13 are the bottom and side views, respectively, of the circuit board 2 and speaker 3 attached to the main base plate 1 in this manner. Figure 14 is an enlarged view of portion B in Figure 12.

[0045] As shown in particular in Figure 12 of these figures, the battery housing 101 of the main base plate 1 is located in the region where the fan-shaped notch 201 of the substrate 2 is formed. In addition, the cylindrical wall 103 of the main base plate 1 is located in the region where the isosceles trapezoidal notch 202 of the substrate 2 is formed. The notch 202 of the substrate 2 abuts against the outer surface of this cylindrical wall 103.

[0046] More specifically, as shown in Figure 14, the notch 202 abuts against the outer surfaces of wall portions 1031, 1033, and 1034, which are among the four wall portions 1031 to 1034 that make up the cylindrical wall 103. As a result, the substrate 2 covers the light-emitting unit housing space and the light-receiving unit housing space formed in the main base plate 1. The rectangular notch 203 of the substrate 2 forms a through hole 216 between it and wall portion 1033. This through hole 216 is a through hole that connects the space between the substrate 2 and the intermediate plate 4 with the light-emitting unit housing space. The rectangular notch 204 of the substrate 2 forms a through hole 217 between it and wall portion 1034. This through hole 217 is a through hole that connects the space between the substrate 2 and the intermediate plate 4 with the light-receiving unit housing space.

[0047] Furthermore, as shown in Figure 12, the antenna 212 connected to the circuit board 2 is held 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. Composition of the middle plate 4 Next, the intermediate plate 4 will be described with reference to Figures 15 to 18. Figures 15 to 18, which will be referenced in this description, are the bottom view, bottom perspective view, top view, and top perspective view of the intermediate plate 4.

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

[0050] The middle plate 4 also has an elliptical ventilation hole 402 formed on the opposite side of the notch 401, with the center of the middle plate 4 in between. This ventilation hole 402 is a vent 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 intermediate plate 4 also has three labyrinth walls 403-405 formed around the ventilation holes 402. These three labyrinth walls 403-405 are plate-shaped walls that protrude vertically from the lower surface of the intermediate plate 4. These three labyrinth walls 403-405 are formed so as not to obstruct the inflow of smoke into the ventilation holes 402, but to obstruct the incidence of external light into the ventilation holes 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. These locking holes 406 and 407 are locking holes into which the hooks of the optical table cover 7 (see Figure 4), which will be described later, are secured.

[0053] The intermediate plate 4 also has eight antenna holders 408-415 that are radially formed around the labyrinth walls 403-405. These eight antenna holders 408-415 are substantially straight plates that protrude vertically from the lower surface of the intermediate plate 4. These eight antenna holders 408-415 have notches at their ends, into which the antenna 212 is fitted.

[0054] The middle plate 4 also has a rectangular through-hole 416 formed on its periphery. The antenna holding portion 108 of the main base plate 1 is inserted through this through-hole 416.

[0055] The middle plate 4 also has a plurality of speaker holes 417 formed adjacent to the U-shaped notch 401. These speaker holes 417 are located 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 notch 401. Of these holes, the switch hole 418 is a through hole through which the inspection switch 207 is inserted. On the other hand, the indicator hole 419 is a light-passing hole for allowing light from the indicator light 208 to pass through.

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

[0058] The intermediate plate 4 also has side walls 421 erected on the peripheral edge 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 base plate 1 is locked into locking hole 422, the hook 1061 of the main base plate 1 is locked into locking hole 423, and the hook 1062 of the main base plate 1 is locked into locking hole 424.

[0060] The middle plate 4 also has a locking hole 425 formed from its periphery to the side wall 421. As shown in Figure 16, this locking hole 425 is positioned to sandwich the labyrinth wall 404 between it and the ventilation hole 402. This locking hole 425 is constructed by connecting a rectangular hole formed on the periphery and a rectangular hole formed on the side wall 421. Of these holes, the antenna holding portion 109 of the main base plate 1 is inserted through the former hole. On the other hand, the hook 1091 of the main base plate 1 is locked into the latter hole.

[0061] Furthermore, the intermediate 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 that protrudes vertically from the upper surface of the intermediate plate 4.

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

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

[0064] The intermediate plate 4 described above is attached to the main base plate 1 so as to cover the circuit board 2 and the speaker 3. At this time, the intermediate plate 4 is fixed to the main base plate 1 by engaging the hooks 1021, 1061, 1062 and 1091 of the main base plate 1 with the locking holes 422 to 425 of the intermediate plate 4. Figures 19 and 20 are the bottom view and side view, respectively, of the intermediate plate 4 attached to the main base plate 1 in this manner. Figure 21 is a cross-sectional view taken along line CC of Figure 20. Figure 22 is an enlarged view of section D in Figure 21.

[0065] As shown in Figure 19 in particular, the battery housing portion 101 of the main base plate 1 is located in the area where the notch 401 of the middle plate 4 is formed. The antenna holding portion 108 of the main base plate 1 is inserted through the insertion hole 416 of the middle plate 4. The antenna holding portion 109 of the main base plate 1 is inserted through the locking hole 425 of the middle plate 4. The antenna 212 is inserted through the antenna hole 420 of the middle plate 4. 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. The inspection switch 207 is inserted through the switch hole 418 of the middle plate 4. The indicator light 208 is visible through the display hole 419 of the middle plate 4.

[0066] Furthermore, as shown in Figure 22 in particular, the lower end of the cylindrical wall 103 of the main base plate 1 is fitted into the space formed by the partition wall 426 of the intermediate plate 4 and the pair of ribs 427 and 428. As a result, the partition wall 426 of the intermediate plate 4 abuts against the outer surfaces of the wall portions 1032 to 1034 that constitute the cylindrical wall 103. Also, the rib 427 of the intermediate 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 has both ends abutting against the outer surfaces of the wall portion 1034, surrounding the through hole 217. In addition, the upper end of this U-shaped portion 4272 is close to the substrate 2 to the extent that it obstructs the passage of insects. Therefore, this U-shaped portion 4272 obstructs the entry of insects into the through hole 217 in the space between the intermediate plate 4 and the substrate 2.

[0067] Furthermore, the ribs 428 of the intermediate plate 4 abut 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 abuts against the outer surface of the wall portion 1033 at both ends, surrounding the through hole 216. In addition, the upper end of this U-shaped portion 4282 is close enough to the substrate 2 to obstruct the passage of insects. Therefore, this U-shaped portion 4282 obstructs the entry of insects into the through hole 216 in the space between the intermediate plate 4 and the substrate 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 referenced in this description, are the bottom view, side view, and top view of the main body cover 5.

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

[0070] Furthermore, as shown in Figure 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 for allowing smoke to flow into the space between the main body cover 5 and the middle plate 4.

[0071] Furthermore, as shown in Figure 25, the main body cover 5 has a pair of switch support portions 503A and 503B formed adjacent to the switch hole 501. These switch support portions 503A and 503B have U-shaped notches into which the shaft portion of the illuminated switch 8 is fitted. The above is a description of the main unit cover 5.

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

[0073] Then, an optical bench cover 7 is attached so as to cover the lower opening of the insect screen ring 6 that has been installed. The optical bench cover 7 has a disc portion, a star-shaped projection formed in the center of the upper surface of the disc portion, and a pair of hooks erected on the periphery of the disc portion. When the optical bench cover 7 is attached to the middle plate 4, its disc portion covers the lower opening of the insect screen ring 6, its projection is inserted between the labyrinth walls 403 to 405 of the middle plate 4, and its pair of hooks are locked into a pair of locking 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, which is housed in the main body cover 5. This illuminated switch 8 has an oval plate portion, a projection portion that protrudes vertically from one end of the plate portion, a columnar portion that is erected vertically at the other end of the plate portion, and a shaft portion formed at the base end of the columnar portion. Furthermore, this illuminated switch 8 is made of a translucent resin material containing a light diffusing material. When this illuminated switch 8 is attached to the main body base plate 1, its projection portion abuts against the inspection switch 207 on the circuit board 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, the insect screen ring 6, optical bench cover 7, and illumination switch 8 are attached, and then 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. In addition, the shaft portion of the illumination switch 8 is held 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, we will explain the function of the ribs 105 on the main base plate 1. As shown in Figure 7, the rib 105 of the main body base plate 1 is a U-shaped rib with both ends connected to the outer surface of the cylindrical wall 103. In addition, as shown in Figure 13, the lower end of this rib 105 is close enough to the substrate 2 to obstruct the passage of insects. Therefore, this rib 105 prevents insects from entering the light-receiving unit housing space formed between the rib and the cylindrical wall 103.

[0077] The main base plate 1 has indentation portions 107A and 107B as described above (see Figure 6). U-shaped through grooves are formed around these indentation 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 base plate 1 and the substrate 2 and reach the vicinity of the light-receiving portion 206. Assuming that there is no rib 105, the insect may enter the optical axis of the light-receiving portion 206, obstructing the light reception of the light-receiving portion 206. If the light reception of the light-receiving portion 206 is obstructed, even if a fire occurs, it will not be detected. Another possibility is that the insect may enter the smoke detection space through the light-passing hole 1036. If it enters the smoke detection space, the light from the light-emitting portion 205 may hit the insect, scatter, and be received by the light-receiving portion 206. If 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 rib 105 prevents insects from entering the light-receiving unit housing space. Therefore, the possibility of false alarms or missed fire detections due to insect intrusion as described above can be reduced.

[0079] Next, we will explain the function of the ribs 427 of the intermediate plate 4. As shown in Figure 22, the rib 427 of the intermediate plate 4 has a U-shaped portion 4272. This U-shaped portion 4272 is a rib that surrounds the through hole 217, with both ends of the rib contacting the outer surface of the cylindrical wall 103. In addition, the upper end of this U-shaped portion 4272 is close enough to the substrate 2 to obstruct the passage of insects. Therefore, this U-shaped portion 4272 prevents insects from entering the through hole 217 in the space between the intermediate plate 4 and the substrate 2.

[0080] The main body cover 5 has ventilation holes 502 as described above (see Figure 24). The middle plate 4 also has display holes 419 as described above (see Figure 15). Insects may enter the space between the middle plate 4 and the substrate 2 through these ventilation holes 502 and display holes 419. If insects enter that space, they may travel through that space and reach the vicinity of the through-hole 217. Assuming that the U-shaped portion 4272 is not present, the insects may enter the light-receiving unit housing space through the through-hole 217. If the insects enter the light-receiving unit housing space, they may obstruct the light reception of the light-receiving unit 206. If the light reception of the light-receiving unit 206 is obstructed, even if a fire occurs, it will not be detected. Another possibility is that the insects may enter the smoke detection space through the light-passing hole 1036. If an insect enters the smoke detection area, the light from the light-emitting unit 205 may hit the insect, scatter, and be received by the light-receiving unit 206. If 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, the presence of the U-shaped portion 4272 prevents insects from entering the through-hole 217. Therefore, the possibility of false alarms or missed fire detections due to insect intrusion can be reduced.

[0082] Next, we will explain the function of the ribs 428 of the intermediate plate 4. As shown in Figure 22, the rib 428 of the intermediate plate 4 has a U-shaped portion 4282. This U-shaped portion 4282 is a U-shaped rib that surrounds the through hole 216, with both ends in contact with the outer surface of the cylindrical wall 103. In addition, the upper end of this U-shaped portion 4282 is close enough to the substrate 2 to obstruct the passage of insects. Therefore, this U-shaped portion 4282 prevents insects from entering the through hole 216 in the space between the intermediate plate 4 and the substrate 2.

[0083] The main body cover 5 has ventilation holes 502 as described above (see Figure 24). The middle plate 4 also has display holes 419 as described above (see Figure 15). 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, it may travel through the space and reach the vicinity of the through hole 216. Assuming that the U-shaped portion 4282 is 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 obstruct the emission of light from the light-emitting unit 205. If the emission of light from the light-emitting unit 205 is obstructed, even if a fire occurs, it will not be detected. Another possibility is that the insect enters 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 hit the insect, scatter, and be received by the light-receiving unit 206. If 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, the presence of the U-shaped portion 4282 prevents insects from entering the through-hole 216. Therefore, the possibility of false alarms or missed fire detections due to insect intrusion can be reduced.

[0085] Next, the function of forming the hook 1091 on the antenna holding portion 109 of the main base plate 1 will be explained with reference to Figure 26. The Figure 26 referred to in this explanation is a cross-sectional view along the EE line in Figure 3. Note that hatching has been omitted in Figure 26 to prevent the drawing from becoming difficult to read.

[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. If an insect enters this cut-off hole 112, it may pass between the inner surface of the main body cover 5 and the outer surface of the middle plate 4, as shown by arrow A1 in the figure, and reach the space between the top surface of the main body cover 5 and the bottom surface of the middle plate 4. However, even if it reaches 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, let's assume a case where a hook is formed on the cylindrical wall 103 instead of the antenna holding portion 109. More specifically, let's assume a main base plate 1A in which a hook 1037 is formed on the cylindrical wall 103. Figure 27 is a bottom view of this main base plate 1A. In the main base plate 1A shown in the figure, a hook 1037 is formed on the outer surface of the wall portion 1032 that constitutes the cylindrical wall 103.

[0088] Let's assume that, due to this change in the position of the hook, a locking hole is formed in the partition wall 426 instead of the side wall 421 of the intermediate plate 4. More specifically, let's assume an intermediate plate 4A in which a locking hole 4261 is formed in the partition wall 426. Figure 28 is a top perspective view of this intermediate plate 4A. In the intermediate plate 4A shown in the figure, a locking hole 4261 is formed in the center of the partition wall 426. The hook 1037 is locked into this locking hole 4261.

[0089] Let's assume that the main base plate 1A and intermediate plate 4A described above are replaced with the main base plate 1 and intermediate plate 4. More specifically, let's assume a smoke detector 100A equipped with the main base plate 1A and intermediate plate 4A. Figure 29 is a longitudinal cross-sectional view of this smoke detector 100A. Note that hatching has been omitted in Figure 29 to prevent the drawing from becoming difficult to read.

[0090] In the smoke detector 100A shown in the figure, a cut-off hole 113 is formed directly above the hook 1037. This cut-off hole 113 is formed when the main body base plate 1A is molded. If an insect enters this cut-off hole 113, it may pass between the partition wall 426 and the side wall 421 of the middle plate 4A, as shown by arrow A2 in the figure, and enter the insect screen ring 6 through the cut-off hole 429 formed below the locking hole 4261. If the insect enters the insect screen ring 6, it may pass between the labyrinth walls 403-405, 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 part 205 may hit the insect and scatter, and be received by the light-receiving part 206. If the scattered light is received by the light-receiving part 206, a fire will be detected even though there is no actual fire. Another possibility is that the insect could enter the light-emitting unit housing space from the smoke detection space through the light-passing hole 1035. If the insect enters the light-emitting unit housing space, it could obstruct the light emission of the light-emitting unit 205, potentially preventing the detection of a fire even if one occurs. Yet another possibility is that the insect could enter the light-receiving unit housing space from the smoke detection space through the light-passing hole 1036. If the insect enters the light-receiving unit housing space, it could obstruct the light reception of the light-receiving unit 206, potentially preventing the detection of a fire even if one occurs.

[0091] In contrast, if a hook 1091 is formed on the antenna holder 109, the cutting hole 112 directly above it will be located outside the insect screen ring 6 when viewed from the side (see Figure 26). Therefore, even if an insect enters the cutting hole 112, it will be difficult for it to enter the insect screen ring 6. Consequently, the possibility of false alarms or missed fire detections due to insect intrusion 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, fire signal transmission process, and wireless channel setting process will be described.

[0093] First, let me explain the fire detection process. When a fire occurs in the monitoring area of ​​the smoke detector 100, the smoke rises towards the ceiling. Once it reaches the ceiling, it flows horizontally along the ceiling surface. When this smoke enters the smoke detector 100 through the ventilation holes 502, it passes through the insect screen ring 6 and the ventilation holes 402 of the intermediate plate 4, and enters the smoke detection space. Upon entering the smoke detection space, the light emitted from the light-emitting unit 205 strikes the smoke particles and is scattered, and the light is received by the light-receiving unit 206. When the light-receiving unit 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 emits an alarm sound from the speaker 3 and transmits a fire signal to other smoke detectors 100 and relay devices via the wireless communication circuit 215. The above is an explanation of the fire detection process.

[0094] Next, we will explain the fire signal transmission process. When the control circuit 214 of the smoke detector 100 receives a fire signal from another smoke detector 100, it emits an alarm sound from the speaker 3. In addition, the control circuit 214 transmits fire signals to yet another smoke detector 100 or relay device via the wireless communication circuit 215. This enables the smoke detectors 100 to be linked together.

[0095] Next, we will explain the wireless channel setting process. When the user presses and holds the registration switch 209 of the smoke detector 100, 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 briefly pressed. In addition, each time the wireless channel is changed, the control circuit 214 emits a guide voice from speaker 3 notifying the wireless channel number. When the registration switch 209 is pressed and held again, the control circuit 214 remembers the number of the currently selected wireless channel and exits the wireless channel setting mode.

[0096] Subsequently, 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. Furthermore, the following modifications may be combined with each other.

[0098] 2-1. Variation 1 The shape of the main base plate 1 shown in Figure 6, etc., is merely an example. The shape of the main base plate 1 may be changed as appropriate depending on the shape of the battery, circuit board 2, and speaker 3 mounted on the smoke detector 100, and the type of electronic components mounted on the circuit board 2.

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

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

[0101] As described above, the rib 104 is in contact with the substrate 2. However, it is not essential that the rib 104 is in contact with the substrate 2. The rib 104 may not be in contact with the substrate 2, and a small gap may be left between them. However, this gap should be large enough to prevent insects from passing through. Specifically, for example, it may be approximately the same size as the mesh of the insect screen ring 6.

[0102] 2-4. Variation 4 The ribs 105 of the main body base plate 1 have a U-shape, as shown in Figure 6. However, this shape is merely an example, and instead of a U-shape, they may have, for example, 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 placed in contact with the substrate 2 without leaving a gap between them.

[0104] 2-5. Variation 5 The shape of the circuit board 2 shown in Figure 9, etc., is merely an example. The shape of the circuit board 2 may be changed as appropriate depending on the shape of the battery and speaker 3 mounted on the smoke detector 100, the shape of the cylindrical wall 103 of the main 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 base plate 1. However, it is not essential to have the notch 202 abut against the outer surface of the cylindrical wall 103. The notch 202 may be placed close to the cylindrical wall 103 with a small gap between them, without abutting against the outer surface of the cylindrical wall 103. However, the gap in this case should be sized to prevent insects from passing through. Specifically, for example, it may be approximately the same size as 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 Figure 14. However, this shape is merely an example, and instead of a rectangular shape, they may have, for example, a semicircular shape.

[0107] 2-7. Variation 7 The shape of the intermediate plate 4 shown in Figure 15, etc., is merely an example. The shape of the intermediate plate 4 may be changed as appropriate depending on the shape of the battery, circuit board 2, and speaker 3 mounted on the smoke detector 100, and the type of electronic components mounted on the circuit board 2.

[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 Figure 22. However, this shape is merely an example, and instead of a 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 placed in 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 Figure 22. However, this shape is merely an example, and instead of a 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 placed in 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 Figure 4. However, this shape is merely an example, and it may have other shapes, such as an elliptical or rectangular shape.

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

[0114] 1...Main base plate, 2...Circuit board, 3...Speaker, 4...Middle plate, 5...Main cover, 6...Insect screen ring, 7...Optical stand cover, 8...Illumination switch, 100...Smoke detector, 101...Battery housing, 102...Speaker housing, 103...Cylindrical wall, 104...Rib, 105...Rib, 106...Circuit board mounting section, 107A, 107B...Push-in section, 108, 109...Antenna holder, 110, 111...Switch holder, 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 part, 416...insertion hole, 417...speaker hole, 418...switch hole, 419...indicator 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 part, 1031-1034...wall part, 1035, 1036...light passage hole, 2121...straight part, 2122...arc part, 2131...straight part, 2132...arc part

Claims

1. The main base plate and An intermediate plate is arranged so as to overlap the main body base plate in the thickness direction of the main body base plate, Insect net and Equipped with, The main body base plate has a wall portion and a hook that form a smoke detection space, provided on the surface on the middle plate side. The intermediate plate has a ventilation hole for allowing smoke to flow into the smoke detection space, and a locking hole provided on the surface of the main body base plate side for locking the hook. The insect screen is positioned on the side of the middle plate opposite to the main body base plate so as to surround the ventilation holes. The hook is positioned outside the insect screen in a direction along the surface of the main body base plate. A smoke detector characterized by the following features.

2. A circuit board is placed between the main body base plate and the middle plate, An antenna used for wireless communication is connected to the aforementioned substrate. Furthermore, The main body base plate has an antenna holding portion that protrudes from the surface on the middle plate side and holds the antenna, The hook is formed on the side of the antenna holding portion that faces away from the wall portion. The smoke detector according to feature 1.

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