Thermal alarm

Abstract

To provide a thermal alarm by which successful heat receiving characteristics can be obtained while being thinned.SOLUTION: A thermal alarm 100 comprises: a plurality of heat detection parts 60a, 60b which are electrically connected with a substrate 50; and an intermediate plate 90 which has formed therein a detection hole 91 into which each of the plurality of heat detection parts 60a, 60b is penetrated, provided in a body part 41 to cover the substrate 50 and divides a circulation space SP into a space arranged with the substrate 50 and a space connected with the circulation hole. A cover 30 comprises a bottom surface facing the body part 41 provided with the substrate 50, the bottom surface is provided with a vertical hole 32a which is the circulation hole and in which vertical current flows, and each heat detection part 60a, 60b is connected with the substrate 50 so that a thermo-sensitive part 61 is located outside the substrate 50 and the intermediate plate 90, and the thermo-sensitive part 61 is located closer to a bottom surface side of the cover 30 than the substrate 50 and the intermediate plate 90 when the inside of the cover 30 is viewed from the bottom surface side.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a heat alarm equipped with a heat detection unit. [Background technology]

[0002] Conventionally, a heat alarm comprises a main body having a circuit board and a heat detection unit mounted on the circuit board to detect heat. The heat detection unit has a heat-sensing element such as a thermistor at its tip. Heat from the hot airflow generated by a fire is transmitted to the heat-sensing element, and a fire is detected when the output value from the heat-sensing element exceeds a certain value. The main body of the heat alarm is also provided with a battery and a speaker, and when a fire is detected, a sound is emitted from the speaker to alert the fire. The heat detection unit is positioned so that it protrudes from the cover of the heat alarm (see, for example, Patent Document 1). In order for the heat-sensing element to receive heat efficiently, space must be provided around it, and in the heat alarm of Patent Document 1, the heat-sensing element is positioned outside the cover. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-141568 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the thermal alarm of Patent Document 1 requires a protector to be provided on the outside of the cover to protect the heat-sensing unit, which increases the thickness of the thermal alarm. On the other hand, if an attempt is made to make the thermal alarm thinner by placing the heat-sensing unit inside the cover, the heat of the hot airflow will be absorbed by the main body and components inside the cover, reducing the temperature of the hot airflow as it passes through the heat-sensing unit. As a result, heat reception characteristics may be worse than in conventional cases where the heat-sensing unit is placed outside the cover and a protector is provided.

[0005] The present invention has been made to solve the above-mentioned problems, and aims to provide a thermal alarm that can be made thinner while still achieving good heat reception characteristics. Here, heat reception characteristics refers to the difference between the actual temperature of the hot air flow and the temperature detected by the alarm, with poor heat reception characteristics referring to an increase in the difference between the actual temperature and the detected temperature, and obtaining good heat reception characteristics referring to the ability to reduce this difference. [Means for solving the problem]

[0006] The thermal alarm of the present invention comprises a main body, a cover having a circulation hole and forming a circulation space between itself and the main body, a circuit board attached to the main body so as to face the cover, a plurality of heat detection units having a heat-sensing unit at their tip and configured to detect the heat of the airflow that has flowed into the circulation space through the circulation hole and electrically connected to the board, and a middle plate formed with a detection hole through which each of the heat detection units passes and attached to the main body so as to cover the board, dividing the circulation space into a space in which the board is disposed and a space connected to the circulation hole, the cover having a bottom surface facing the main body on which the board is attached, and a vertical hole that serves as the circulation hole and through which a vertical airflow flows in, and each of the heat detection units is connected to the board so that when the inside of the cover is viewed from the bottom side, the heat-sensing unit is located outside the board and the middle plate, and is located closer to the bottom of the cover than the board and the middle plate. In addition, the above-mentioned thermal alarm is provided with a speaker that is provided in the main body and emits sound, and the middle plate is provided in the main body so as to cover the substrate and the speaker, and has a speaker hole provided opposite the speaker, and the speaker hole in the middle plate is positioned so as not to overlap with the vertical hole and to be covered by the bottom surface. [Effects of the Invention]

[0007] According to the present invention, it is possible to provide a thermal alarm with improved detection accuracy by reducing the thickness of the thermal alarm while suppressing the temperature drop of the air flow in the circulation space before it reaches the heat-sensing part and suppressing deterioration of the substrate due to direct contact between the substrate and the air in the space connected to the circulation hole. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a side view showing the appearance of a thermal alarm 100 according to a first embodiment. [Figure 2] FIG. 2 is a bottom view showing the external appearance of the heat alarm 100. [Figure 3] 2 is an explanatory diagram showing the internal configuration of the housing 10 of the heat alarm 100. FIG. [Figure 4] FIG. 4 is a cross-sectional view showing the cross section BB of FIG. [Figure 5] FIG. 4 is a cross-sectional view showing the CC cross section of FIG. [Figure 6] FIG. 3 is a cross-sectional view showing the cross section AA of FIG. 2. [Figure 7] FIG. 10 is an explanatory diagram showing the internal configuration of a housing 310 of a thermal alarm 300 according to a second embodiment. [Figure 8] FIG. 8 is a cross-sectional view showing the cross section DD of FIG. 7. DETAILED DESCRIPTION OF THE INVENTION

[0009] Embodiment 1 Fig. 1 is a side view showing the appearance of a heat alarm 100 according to embodiment 1. Fig. 2 is a bottom view showing the appearance of the heat alarm 100. The heat alarm 100 is installed in a monitored space, such as the interior of a house, and monitors the ambient temperature. The heat alarm 100 alerts you to a fire when the ambient temperature reaches or exceeds a certain temperature.

[0010] 1 and 2, the heat alarm 100 comprises a base 20 attached to a ceiling 200, a main body 40, a cover 30 with ventilation holes through which airflow flows, and a push-in member 34 attached to the cover 30. The cover 30 and main body 40 form the housing 10 of the heat alarm 100, and the housing 10 is detachably attached to the base 20. The push-in member 34 is an inspection button that an operator presses when commencing an operational test of the heat alarm 100. In the following explanation, the direction of arrow X represents the width direction of the heat alarm 100, the direction of arrow Y represents the depth direction, and the direction of arrow Z represents the height direction.

[0011] FIG. 3 is an explanatory diagram showing the internal configuration of the housing 10 of the thermal alarm 100. As shown in FIG. 3, the thermal alarm 100 comprises a speaker 70, a battery 80, and a middle plate 90 (see FIG. 4), with the speaker 70 and middle plate 90 installed within the housing 10. The main body 40 comprises a disk-shaped main body section 41 and a circuit board 50 on which various electronic components such as heat detection sections 60a and 60b are mounted. An airflow circulation space SP is formed between the main body section 41 and the cover 30. Hereinafter, unless there is a need to particularly distinguish between the heat detection sections 60a and 60b, each heat detection section 60a, 60b will be described as a heat detection section 60. The heat detection section 60 is connected so that the heat-sensing section 61 is located on the floor side of the circuit board 50. Here, "located on the floor side" means located on the side opposite the ceiling 200, and in FIG. 3 refers to the underside 50b of the circuit board 50.

[0012] Fig. 4 is a cross-sectional view showing the BB cross section of Fig. 3. Fig. 5 is a cross-sectional view showing the CC cross section of Fig. 3. As shown in Figs. 4 and 5, the main body 40 is provided below the base 20, and a battery 80 is housed between the base 20 and the main body 41. A board 50 and a speaker 70 are provided on the underside 41b of the main body 41, and a middle plate 90 is disposed below the board 50 and the speaker 70.

[0013] 1 and 2, the cover 30 is formed in a cylindrical shape with a bottom, and has a cylindrical cover side portion 31, a disk-shaped cover bottom portion 32, and a slit portion 33 provided between the cover side portion 31 and the cover bottom portion 32. The cover side portion 31 surrounds the outer periphery of the main body 40. The cover bottom portion 32 is disposed opposite the lower surface 41b of the main body portion 41 on which the substrate 50 and the like are provided.

[0014] A through-hole vertical hole 32a is formed on each of the left and right sides of the cover bottom portion 32. The inner peripheral wall 32b of each vertical hole 32a is provided with a plurality of protruding contact prevention portions 32c, and the vertical holes 32a are shaped, for example, like clover leaves. Each vertical hole 32a is located below each heat detection element 60a, 60b, and the contact prevention portions 32c protect the heat detection elements 60a, 60b from contact with fingers, instruments, and the like. A vertical airflow flows into the circulation space SP through each vertical hole 32a. Here, the vertical airflow refers to an airflow that flows in a direction perpendicular to the surface of the ceiling 200. A buttonhole 32d is formed in the center of the cover bottom portion 32 to expose the push-in member 34 from the cover bottom portion 32.

[0015] The slit section 33 has a horizontal hole 33a that opens so as to extend in the circumferential direction of the cover 30, multiple main supports 33b that extend in the vertical direction (direction of arrow Z), multiple sub-supports 33c that are provided between adjacent main supports 33b, and a ring-shaped partition member 33d that separates the horizontal hole 33a. Each main support 33b supports the cover bottom section 32. Each sub-support 33c is thinner than the main supports 33b and supports the partition member 33d together with the main supports 33b. The horizontal hole 33a is separated into two sections by the ring-shaped partition member 33d. A horizontal airflow flows into the circulation space SP through the horizontal hole 33a. The airflow in the circulation space SP also flows out of the thermal alarm 100 through the horizontal hole 33a. Here, the horizontal airflow refers to an airflow that flows in a direction parallel to the surface of the ceiling 200.

[0016] 3 and 4, the main body 41 has a board installation section 43 that forms a space in which the board 50 is housed, and a battery accommodating section 42 that forms a space in which the battery 80 is housed. The board installation section 43 is provided, for example, in the center of the main body 41. The battery accommodating section 42 is provided on the outer periphery of the main body 41 relative to the board installation section 43. Specifically, the battery accommodating section 42 is provided forward in the depth direction (arrow Y direction) and to the right in the width direction (arrow X direction) relative to the center O1 of the main body 41. Here, the center O1 of the main body 41 coincides with the center of the circulation space SP.

[0017] The substrate mounting portion 43 accommodates a rectangular substrate 50 with one corner cut out in an arc shape, with the cutout portion 50a positioned rearward and to the left of the center O1 of the main body portion 41. The substrate mounting portion 43 is a wall portion formed along the shape of the substrate 50 so as to protrude toward the cover bottom surface portion 32, and the substrate 50 is accommodated so that the edge of the substrate 50 faces the substrate mounting portion 43.

[0018] A cylindrical battery 80 is housed in the battery housing section 42, with its axis oriented in the width direction (direction of arrow X). The battery housing section 42 has a concave shape on the top surface 41a side of the main body section 41 that conforms to the outer shape of the battery 80, resulting in a raised shape on the bottom surface 41b side of the main body section 41. The raised bottom surface 41b faces the cover bottom surface section 32 with no gap between them, thereby separating the flow space SP.

[0019] A control circuit is provided on the board 50, and operating power for the control circuit is supplied from a battery 80. A switch 51 that detects when the push-in member 34 is pressed, a confirmation light 52 formed of, for example, an LED or the like that lights up when a fire is detected, and multiple heat detectors 60a, 60b that detect the heat of hot airflow are mounted on the underside 50b of the board 50. As shown in Figures 4 and 5, pinholes 50c, 50d are formed in the board 50 for mounting the heat detectors 60a, 60b, respectively.

[0020] The control circuit receives the output values ​​of the heat detection units 60a, 60b and determines the ambient temperature based on the output values. When the control circuit determines that the ambient temperature is equal to or higher than a certain temperature based on at least one of the heat detection units 60, it outputs a fire signal to the speaker 70. The control circuit may also be configured to output a fire signal to the speaker 70 when there is a temperature change of more than a set value in a short period of time.

[0021] 3 and 5, the speaker 70 has a circular shape and is installed on the underside 41b of the main body 41. The speaker 70 is located on the rear left side of the center O1 of the main body 41, with a portion of the speaker 70 located in the cutout 50a of the circuit board 50. That is, as shown in FIG. 3, the battery holder 42 is located on one side of an imaginary line Lv that passes through the center O1 of the main body 41, and the speaker 70 is located on the imaginary line Lv, sandwiching the center O1 between the battery holder 42 and the speaker 70. Here, the imaginary line Lv is a line that passes through the center O1 of the main body 41 and connects the battery holder 42 and the speaker 70, and does not necessarily have to pass through the center of the battery holder 42 and the center of the speaker 70.

[0022] The speaker 70 includes a diaphragm 71 that generates sound by vibration, and is electrically connected to the substrate 50. When a fire signal is input from the control circuit of the substrate 50 to the speaker 70, the speaker 70 vibrates the diaphragm 71 to generate sound.

[0023] 6 is a cross-sectional view taken along the line AA in FIG. 2. The push-in member 34 is an inspection button that is operated during an operation test of the heat alarm 100, and also functions as an indicator light in the event of a fire. The push-in member 34 is made of a translucent material such as acrylic resin, and has a button portion 34a exposed from the buttonhole 32d in the cover bottom portion 32, and a guide portion 34b that extends toward the circuit board 50. The tip of the guide portion 34b is located directly below the switch 51 and the confirmation light 52 provided on the circuit board 50. The position at which the push-in member 34 is provided can be determined based on the position of the circuit board 50 on the main body 40. During an operation test, when an operator or the like presses the button portion 34a, the guide portion 34b presses and turns on the switch 51, initiating an operation to inspect the function of the heat alarm 100. On the other hand, when a fire is detected and the confirmation light 52 is turned on in the event of a fire outbreak, the light projected from the confirmation light 52 is guided by the guide portion 34b, causing the button portion 34a to emit light.

[0024] Each of the heat detection units 60a, 60b has a heat-sensing unit 61 that detects heat, a rod-shaped lead unit 62 made of a lead wire, and a pin 63 attached to the base end of the lead unit 62. The heat-sensing unit 61 is made of, for example, a thermistor or the like whose resistance changes in response to heat transmitted from an airflow, and converts the temperature change into an electrical signal for output.

[0025] The heat-sensing unit 61 is attached to the tip of the lead 62, and the heat-sensing unit 61 and the lead 62 are integrally coated. When the pins 63 of each heat detection unit 60a, 60b are inserted into the pin holes 50c, 50d of the circuit board 50, the base end of each lead 62 is connected to the circuit board 50, and each heat-sensing unit 61 is electrically connected to the control circuit of the circuit board 50. In other words, each heat detection unit 60a, 60b is connected to the circuit board 50 so as to be connected to the floor side of the circuit board 50. Note that each lead 62 may be connected to the circuit board 50 by soldering.

[0026] As shown in Figures 5 and 6, the middle plate 90 covers the circuit board 50 and the speaker 70. A gap is provided between the middle plate 90 and the cover 30. The middle plate 90 has a guide hole 92 through which the guide portion 34b of the pushing member 34 passes, two detection holes 91 provided on the left and right of the guide hole 92, and a speaker hole 93 provided opposite the diaphragm 71 of the speaker 70. Each of the heat detection units 60a, 60b passes through each detection hole 91. The speaker hole 93 is formed by a plurality of small holes provided radially from the center of the diaphragm 71. Sound generated by the speaker 70 passes through the speaker hole 93 and is transmitted to the outside via the circulation space SP and the cover 30.

[0027] As shown in FIG. 3, the two heat detecting units 60a, 60b are arranged along a center line Lc on either side of the center O1 of the main body 41, with each heat detecting unit 61 facing outward. The center line Lc is a straight line passing through the center O1 of the main body 41, and is set separately from the imaginary line Lv to avoid structures. That is, the heat detecting units 61 of the heat detecting units 60a, 60b are arranged at positions that deviate from the imaginary line Lv. Specifically, if the regions formed by dividing the flow space SP into two by the imaginary line Lv are defined as a first region R1 and a second region R2, the heat detecting unit 61 of one heat detecting unit 60a is located in the first region R1, and the heat detecting unit 61 of the other heat detecting unit 60b is located in the second region R2. By arranging such a structure and each heat detection unit 60a, 60b, areas where airflow is difficult to pass through are concentrated on the diagonal of the circulation space SP, and a space where airflow can easily pass through is secured at a position away from the virtual line Lv, allowing the two heat sensing units 61 to detect the heat of the hot airflow in each area.

[0028] 6, the lead portions 62 of the heat detection units 60a, 60b are attached at an angle to the substrate 50, and gradually approach the cover bottom portion 32 from their base ends to their tips. Hereinafter, the angle formed between the lower surface 50b of the substrate 50 and the lead portions 62 is referred to as the inclination angle θ. Each lead portion 62 has a length such that its tip is positioned outside the outer periphery of the substrate 50.

[0029] The positions of the heat-sensing parts 61 provided at the tips of the lead parts 62 will be described in detail. In the height direction (arrow Z direction), each heat-sensing part 61 is located facing the horizontal hole 33a and is disposed between the circuit board 50 and the cover bottom part 32. Each heat-sensing part 61 is also disposed on the outer periphery side of the outer edge 50e of the circuit board 50, and is located between the outer edge 50e of the circuit board 50 and the cover side part 31. In particular, the heat-sensing part 61 of the heat detection part 60b is disposed so as to be located outside the battery housing part 42 in the width direction (arrow X direction), as shown in Figures 3 and 4, and is therefore more susceptible to hot airflow F2, which will be described later.

[0030] This configuration of the heat detection units 60a, 60b ensures a certain distance between each heat-sensing element 61 and the main body 40, preventing the heat of the airflow passing through the heat-sensing element 61 from being absorbed by the main body 40. This allows each heat-sensing element 61 to receive heat efficiently. Furthermore, since each heat-sensing element 61 is closer to the cover 30 than the base end of the lead 62, and the two heat-sensing elements 61 are arranged on the center line Lc with the center O1 in between, there is no significant delay in detection regardless of the direction of airflow entering the cover 30. In other words, directivity can be reduced. Furthermore, the airflow flowing in from the vertical hole 32a flows not only through the horizontal hole 33a but also into the space above each heat-sensing element 61, improving the airflow and increasing the amount of airflow entering from the vertical hole 32a.

[0031] When each heat-sensing part 61 is disposed outside the outer periphery of the substrate 50, the inclination angle θ of the lead part 62 may be 0°. Even in this case, each heat-sensing part 61 is spaced apart from the substrate 50 and the main body part 41, and a space is provided above each heat-sensing part 61, thereby achieving good heat-receiving characteristics.

[0032] The flow of air during a fire will be explained with reference to Figure 1. When a fire breaks out in the monitored space, a vertical airflow is generated from the source of the fire toward the ceiling 200, and after reaching the ceiling 200, the direction of the airflow becomes parallel to the ceiling 200 and flows along the ceiling 200 as a horizontal airflow. If the source of the fire is directly below the heat alarm 100, the vertical airflow will reach the cover bottom part 32. Furthermore, if the source of the fire is not directly below the heat alarm 100, all of the vertical airflow rising from the source of the fire will reach the ceiling 200, flow along the ceiling 200 as a horizontal airflow, and reach the heat alarm 100.

[0033] Next, the flow of horizontal air currents that reach the slit section 33 of the heat alarm 100 will be explained with reference to Figure 3. The position and direction into which the horizontal air currents flow will differ depending on the location of the fire source. First, the case where the fire source is located to the front of the heat alarm 100 will be explained using heat air currents F1 to F3.

[0034] Hot air flow F1 reaches slit 33 at the front center position, flows into housing 10 through horizontal hole 33a, flows along battery housing 42, transfers heat to heat detection unit 60a, and exits housing 10 through horizontal hole 33a. Hot air flow F2 reaches slit 33 to the right of hot air flow F1, flows into housing 10 through horizontal hole 33a, travels along right side surface 42a of battery housing 42, transfers heat to heat-sensing element 61 of heat detection unit 60b located outside right side surface 42a, and exits housing 10 through horizontal hole 33a. Hot air flow F3 reaches slit 33 at the front left position, flows into housing 10 through horizontal hole 33a, and blows through the space to the left of battery housing 42. At this time, hot air flow F3 passes through heat-sensing element 61 of heat detection unit 60a immediately after entering housing 10, so heat is efficiently transferred from hot air flow F3 to heat detection unit 60a.

[0035] In this way, even when there is a structure such as the battery housing section 42, the hot air current F2 passes through the heat detection section 60b, and the hot air currents F1 and F3 pass through the heat detection section 60a. Therefore, if the source of a fire is to the front of the heat alarm 100, heat will be quickly detected by at least one of the two heat detection sections 60a, 60b, and the heat alarm 100 will be able to alert the fire without delay.

[0036] For example, a hot air current flowing from a direction such as hot air current F3 is effective on heat detection unit 60a, but is unlikely to hit heat detection unit 60b due to the presence of battery housing 42. However, because heat detection units 60a and 60b are positioned symmetrically about center O1 and are positioned on the outer periphery to avoid structures, at least one of them can efficiently detect heat no matter from which direction the hot air current flows through the 360°.

[0037] Next, we will use hot air flows F4 to F6 to explain the case where the source of fire is located behind the thermal alarm 100. Hot air flow F4 reaches slit 33 on the left rear side, flows into housing 10 through horizontal hole 33a, and passes through the gap between middle plate 90, located below speaker 70, and cover bottom 32. Hot air flow F4 then curves toward the wider space to the left of speaker 70, transfers heat to heat-sensing element 61 of heat detection unit 60a, and flows out through horizontal hole 33a. Hot air flow F5 reaches slit 33 at the center rear side, and then curves from the narrow space between speaker 70 and cover bottom 32 to the wider space between middle plate 90 and cover bottom 32, or to the even wider space on the right side, transfers heat to heat detection unit 60b, and flows out of housing 10. This flow is also influenced by the presence of battery compartment 42 on the forward direction side. Hot air current F6 reaches slit portion 33 on the rear right side, flows into housing 10 through horizontal hole 33a, and blows through the space to the right of speaker 70. At this time, hot air current F6 passes through heat-sensing portion 61 of heat detection unit 60b immediately after flowing into housing 10, so heat is efficiently transferred from hot air current F6 to heat detection unit 60b.

[0038] In this way, even when there is a structure such as a speaker 70, the hot air current F4 passes through the heat detection unit 60a, and the hot air currents F5 and F6 pass through the heat detection unit 60b. Therefore, even if the source of the fire is located behind the heat alarm 100, heat will be detected quickly by at least one of the two heat detection units 60a, 60b, allowing the heat alarm 100 to alert the fire without delay.

[0039] Furthermore, if the source of the fire is to the left of the heat alarm 100, the horizontal airflow will reach a position to the left of the slit 33 and flow into the housing 10 through the horizontal hole 33a, immediately transferring heat to the heat detection unit 60a. Similarly, if the source of the fire is to the right of the heat alarm 100, the horizontal airflow will reach a position to the right of the slit 33 and flow into the housing 10 through the horizontal hole 33a, immediately transferring heat to the heat detection unit 60b. In this way, the heat alarm 100 can quickly detect a fire regardless of the location of the source of the fire.

[0040] Next, referring to FIG. 6, the flow of vertical airflow when the source of the fire is directly below the thermal alarm 100 will be described. The hot airflow F8 shown in FIG. 6 represents the flow of vertical airflow reaching the vertical holes 32a in the cover bottom portion 32 when the source of the fire is directly below the thermal alarm 100. The hot airflow F8 flows into the housing 10 through each vertical hole 32a, where it directly strikes each heat-sensitive element 61, transferring heat. Subsequently, a portion F8a of the hot airflow F8 flows out of the housing 10 through the horizontal hole 33a. The remaining portion F8b of the hot airflow F8 flows into the space between the heat-sensitive element 61 and the main body portion 41, strikes the underside 41b of the main body portion 41, and is guided to the slit portion 33, where it flows out through the horizontal hole 33a. In this way, the hot airflow F8 can travel further after passing through the heat-sensitive element 61, thereby facilitating the inflow of the hot airflow from each vertical hole 32a. Furthermore, since the heat-sensing part 61 and the main body part 41 are spaced apart, the heat of the hot air current is less likely to be absorbed by the main body part 41, and the heat-sensing part 61 is more likely to receive the heat.

[0041] On the other hand, the hot air flow that arrives outside each vertical hole 32a flows along the cover bottom portion 32, and a portion of it flows into the cover 30 through the vertical holes 32a, and the remaining portion flows through the outer surface of the cover bottom portion 32 to the ceiling 200.

[0042] As described above, in the first embodiment, each heat detection unit 60a, 60b is connected to the substrate 50 so that the heat sensing unit 61 is located closer to the outer periphery of the main body 41 than the position where it is connected to the substrate 50. Furthermore, the two heat sensing units 61 are arranged on a line segment passing through the center O1 of the main body 41, sandwiching the center O1. This allows the hot airflow to pass through one of the heat sensing units 61, even when the heat detection units 60a, 60b are provided inside the cover 30, before the heat of the hot airflow is absorbed by the main body 41, the substrate 50, etc., and the temperature drops. Furthermore, the hot airflow can be directed at the heat sensing unit 61 without being obstructed by the lead portion 62 of the heat detection unit 60. Therefore, the thermal alarm 100 can be made thinner without using a protector, while still achieving good heat receiving characteristics.

[0043] Generally, the type and arrangement of the structures housed within the housing 10 differ depending on the model, etc. Therefore, simply installing the heat detection unit within the cover 30 will result in high directionality depending on the arrangement of the structures. On the other hand, by carefully arranging the two heat-sensing units 61, the heat alarm 100 can reduce the bias in sensitivity that occurs depending on the location of the fire source, and achieve good heat-receiving characteristics.

[0044] Furthermore, the heat-sensing part 61 of each heat detection unit 60a, 60b is disposed between the main body 41 and the cover bottom part 32 facing the main body 41, and is provided so that the heat detection part 60 protrudes toward the floor side of the board. In other words, the heat detection part 60 provided on the board inside the housing 10 is provided so that it protrudes toward the cover side, which is on the floor side, rather than toward the main body side, which is on the ceiling side. This allows the heat-sensing part 61 to be separated from the main body 41 and the board 50 and to be brought closer to the horizontal hole 33a and vertical hole 32a, which are the circulation holes. Therefore, the hot airflow that flows into the circulation space SP can be quickly passed through the heat-sensing part 61, allowing each heat detection unit 60a, 60b to quickly and efficiently detect the heat of the airflow.

[0045] Furthermore, the heat-sensing portion 61 of each heat detection unit 60a, 60b is disposed outside the outer edge 50e of the substrate 50. As a result, the substrate 50 is not present above the heat-sensing portion 61, and a space is provided between the heat-sensing portion 61 and the main body 41, which suppresses a temperature drop in the hot airflow due to the substrate 50 and ensures a sufficient amount of heat at the heat-sensing portion 61. Furthermore, when the vertical hole 32a is provided, the airflow that has passed through the heat-sensing portion 61 penetrates further upward, facilitating the passage of air within the housing 10 and promoting the outflow and inflow of the hot airflow. Therefore, compared to when the substrate 50 is provided above the heat-sensing portion 61, a larger amount of hot airflow passes through the heat-sensing portion 61, resulting in better heat-receiving characteristics.

[0046] Embodiment 2 Figure 7 is an explanatory diagram showing the internal configuration of the housing 310 of a thermal alarm 300 according to embodiment 2. Figure 8 is a cross-sectional view showing the DD cross section of Figure 7. Figure 8 shows the main body 340 with the middle plate 390 attached. In embodiment 2, the layout of the structures, the shape of the main body 340, the shape of the middle plate 390, the shape of the board 350, and the layout of the heat detection units 60a, 60b differ from embodiment 1. Hereinafter, in embodiment 2, the same components as in embodiment 1 are designated by the same reference numerals, and description thereof will be omitted.

[0047] The battery accommodating section 342 is provided to extend forward from the center O1 of the main body section 341, and the battery 80 is accommodated in the battery accommodating section 342 with its axial direction facing the depth direction (direction of arrow Y). The speaker 70 is arranged on the left side of the battery accommodating section 342. The board 350 is arranged below the main body section 341, spanning from the rear side of the speaker 70 and battery accommodating section 342 to the right side of the battery accommodating section 342.

[0048] The middle plate 390 is provided below the main body 341 so as to cover the circuit board 350 and the speaker 70. The right side of the middle plate 390 extends forward along the right side surface 342a of the battery housing section 342 to the outer periphery of the main body 341. A flow space SP is formed between the main body 341 on which the middle plate 390 is provided and the cover 30. By providing the middle plate 390, it is possible to reduce the unevenness of the flow space SP and reduce resistance.

[0049] The middle plate 390 is also formed with a guide hole 392 through which the guide portion 34b of the pushing member 34 passes, two detection holes 391, and a speaker hole 393 provided opposite the diaphragm 71 of the speaker 70. The two detection holes 391 are provided at positions opposite the base ends of the two heat detection units 60a, 60b provided on the left and right sides of the substrate 350.

[0050] Each of the heat detection units 60a, 60b is electrically connected and fixed to the substrate 350 by soldering the base end of the lead portion 62 to the substrate 350. The lead portion 62 is inserted into the detection hole 391 of the middle plate 390, and the heat sensing unit 61 is disposed between the middle plate 390 and the cover bottom portion 32. The heat detection units 60 are provided on the left and right sides of the substrate 350, which is disposed rearward of the center O1 of the main body portion 341, and each lead portion 62 is fixed to the substrate 350 so as to extend forward and toward the outer periphery, and the two heat sensing units 61 are disposed on the center line Lc with the center O1 of the main body portion 41 in between.

[0051] Furthermore, the shape of the substrate 350 is formed so that the outer periphery is recessed at the position of the heat-sensing portion 61. As a result, also in the second embodiment, each heat-sensing portion 61 is disposed on the outer periphery side of the outer edge 350e of the substrate 350, and is positioned between the outer edge 350e of the substrate 350 and the cover side surface portion 31.

[0052] Furthermore, the length Dd of the lead portion 62 of the heat detection unit 60 is shorter than the diameter Ds of the speaker 70. The heat sensing unit 61 is located on the outer periphery of the main body 341 by 80% or more of the diameter of the main body 341. With this configuration, the heat sensing unit 61 is positioned near the slit portion 33, making it easier for the heat sensing unit 61 to receive heat, and reducing the structure that protrudes from the main body 341 into the flow space SP makes it easier for hot air to pass through. In Figure 7, the lead portion 62 of the heat detection unit 60 is arranged so as to circumscribe the speaker 70, but the lead portion 62 may be arranged in any manner as long as the heat sensing unit 61 is located on the diameter of the main body.

[0053] Next, the flow of horizontal air currents that reach the thermal alarm 300 will be described with reference to Figure 7. If the source of the fire is on the front side of the thermal alarm 300, hot air current F12 that reaches slit section 33 at the front left position flows into housing 310 via horizontal hole 33a, transfers heat to heat detection unit 60a, and flows out of housing 310 via horizontal hole 33a. Hot air current F15 that reaches slit section 33 at the front right position flows into housing 310 via horizontal hole 33a, transfers heat to heat detection unit 60b, and flows out of housing 310 via horizontal hole 33a.

[0054] If the source of the fire is to the rear of the thermal alarm 300, hot air current F13 that reaches the slit section 33 at the rear left position flows into the housing 310 via the horizontal hole 33a, transfers heat to the heat detection unit 60a, and flows out of the housing 310 via the horizontal hole 33a. Hot air current F16 that reaches the slit section 33 at the rear right position flows into the housing 310 via the horizontal hole 33a, transfers heat to the heat detection unit 60b, and flows out of the housing 310 via the horizontal hole 33a.

[0055] Here, the hot air currents F12 and F15 flowing in from the front and the hot air currents F13 and F16 flowing in from the rear travel approximately the same distance from when they enter the housing 310 to when they reach the heat-sensing unit 61. For example, if the line connecting the two heat-sensing units 61 is located at the rear and does not pass through the center O1, the distance from when they enter the housing 310 to when they reach the heat-sensing unit 61 will be longer when the source of the fire is at the front than when it is at the rear, and detection may be delayed. On the other hand, in a configuration such as the heat alarm 300 in which the two heat-sensing units 61 are arranged on the center line Lc with the center O1 between them, there is no significant difference in the time it takes to detect heat whether the source of the fire is at the front or the rear.

[0056] If the source of the fire is on the left side of the thermal alarm 300, the hot air current F11 that reaches the slit section 33 at the left side will flow into the housing 310 from the horizontal hole 33a, immediately pass through the heat detection section 60a, bend backward when it hits the battery housing section 342, and flow out through the horizontal hole 33a. The hot air current F11 does not pass through the heat-sensing section 61 of the heat detection section 60b, but because it passes through the heat detection section 60a immediately after flowing into the housing 310, heat is efficiently transferred from the hot air current F11 to the heat detection section 60a.

[0057] If the source of the fire is on the right side of the thermal alarm 300, the hot air flow F14 will hit the battery storage section 342 and bend, so it will not pass through the heat-sensing section 61 of the heat detection section 60a, but will flow into the housing 310 and immediately pass through the heat detection section 60b, so the heat detection section 60b can efficiently detect the heat from the hot air flow F14.

[0058] Furthermore, when hot air current F17 flows from the diagonally front right side of the main body toward the center, the flow is blocked by the battery housing section 342, making it difficult for heat to be transmitted to the heat detection unit 60a. However, because heat detection unit 60b is located symmetrically with respect to the center O1, heat detection unit 60a can efficiently detect heat. Furthermore, when hot air current F18 flows from the diagonally rear left side toward the center, heat detection unit 60a is located near the horizontal hole 33a, allowing heat to be efficiently detected. This makes it possible for the two heat detection units 60a and 60b to combine to detect hot air currents from any direction within a 360° range.

[0059] As described above, in the second embodiment as well, the heat detection units 60a, 60b are connected to the substrate 50 so that the heat sensing unit 61 is positioned closer to the outer periphery of the main body 41 than the position where it is connected to the substrate 50, and the two heat sensing units 61 are arranged on the center line Lc with the center O1 between them. As a result, in the thermal alarm 300 of the second embodiment as well, good heat receiving characteristics can be obtained while being made thinner, just like in the first embodiment.

[0060] The present invention is not limited to the above-described embodiments, and various modifications can be made. For example, the number of heat detection units 60 may be three or more. Furthermore, the first structure and the second structure are not limited to the battery holder 42 and the speaker 70. For example, the first structure may be defined as the structure that occupies the largest volume in the space formed between the main body 40 and the cover 30, and the second structure may be defined as the structure that occupies the next largest volume after the first structure.

[0061] Next, we will explain the vertical holes. Because the heat-sensing element 61 above the vertical hole 32a is visible from the front, as shown in Figure 2, it is subject to design restrictions (e.g., vertical holes must be arranged symmetrically, or the heat-sensing element 61 must be located in the center of the vertical hole 32a). However, if good heat-receiving characteristics are obtained, the vertical hole 32a is not necessarily provided. Alternatively, while the embodiment has been described with a vertical hole 32a provided at the bottom of each of the heat-sensing elements 61, for example, in a heat alarm using two heat detectors 60, the vertical hole 32a may be provided only in the heat-sensing element 61 of one of the heat detectors 60a. In other words, the portion of the cover facing the heat-sensing element 61 of the other heat detector 60b may be left unperforated and closed, eliminating the need for a vertical hole. In this way, the heat-sensing element 61 of the heat detector 60b on the side without the vertical hole is not visible from the outside, eliminating the design restrictions described above and allowing for flexible design of the installation position of the heat detector 60 on the board 50. In other words, since there is no vertical hole 32a, the position of the heat-sensing part 61 of the heat detection part 60b does not have to be symmetrical as long as it is on the diameter of the main body 40. For example, the heat-sensing part 61 of the heat detection part 60a facing the vertical hole 32a may be positioned further toward the outer periphery of the main body part 41 to increase the heat receiving efficiency.

[0062] 2, the shape of the vertical holes 32a is not limited to that shown in Fig. 2, and they may be circular or slit-shaped. When the vertical holes are slit-shaped, their length can be approximately the same as the length Dd of the lead portion of the heat detection unit 60, and their width can be approximately 5 mm to prevent fingers from entering. The vertical holes may be of any shape, taking into account the shape and size of the holes, as long as they allow a sufficient vertical airflow to flow into the circulation space SP and the heat-sensing unit cannot be easily touched by fingers, etc., and the number of holes can also be freely determined according to the number of heat detection units 60.

[0063] Here, we will discuss the location of the heat detection unit 60. The heat-sensing unit 61 formed at the tip of the heat detection unit 60 is desirably located on the outer periphery of the main body 40, as close to the circulation holes as possible. This is because the closer to the outer periphery of the main body 40 it is, the more it comes into contact with hot air currents that are at a higher temperature, thereby improving heat reception efficiency. As mentioned above, since the hot air currents entering the main body 40 include horizontal and vertical air currents, the heat-sensing unit 61 may be located at approximately equal distances from both the horizontal hole 33a and the vertical hole 32a.

[0064] In the above embodiment, a thermal fire alarm equipped with a battery 80 and a speaker 70 has been described, but the present invention may also be applied to a thermal detector that does not have a battery 80 or a speaker 70. [Explanation of symbols]

[0065] 10, 310 housing, 20 base, 30 cover, 31 cover side portion, 32 cover bottom portion, 32a vertical hole, 32b inner peripheral wall, 32c contact prevention portion, 32d button hole, 33 slit portion, 33a horizontal hole, 33b main support, 33c sub-support, 33d partition member, 34 push-in member, 34a button portion, 34b guide portion, 40, 340 main body, 41, 341 main body portion, 41a main body top surface, 41b main body bottom surface, 42, 342 battery storage portion, 42a, 342a right side surface, 43 board installation portion, 50, 350 board, 50a cutout portion, 50b (board) bottom surface, 50c pin hole, 50d pin hole, 50e, 350e outer edge, 51 Switch, 52 confirmation light, 60, 60a, 60b heat detection part, 61 heat-sensitive part, 62 lead part, 63 pin, 70 speaker, 71 diaphragm, 80 battery, 90, 390 middle plate, 91, 391 detection hole, 92, 392 guide hole, 93, 393 speaker hole, 100, 300 heat alarm, 200 ceiling, Dd length of lead part, Ds diameter of speaker, F1, F2, F3, F4, F5, F6, F7, F8, F11, F12, F13, F14, F15, F16, F17, F18 hot air flow, Lc center line, Lv virtual line, O1 center (of main body), R1 first area, R2 second area, SP circulation space, θ inclination angle.

Claims

1. a main body; a cover having a flow hole and forming a flow space between the cover and the main body; a substrate provided on the main body portion so as to face the cover and having a circuit; a plurality of heat detecting units each having a heat sensitive portion at a tip thereof and configured to detect the heat of the airflow flowing into the flow space through the flow hole, the heat detecting units being electrically connected to the substrate; a middle plate having detection holes through which the plurality of heat detecting units are passed, the middle plate being provided in the main body portion so as to cover the substrate, and dividing the flow space into a space in which the substrate is disposed and a space connected to the flow hole; Equipped with the cover has a bottom surface facing the main body portion on which the substrate is provided, The bottom surface is provided with a vertical hole, which is the circulation hole and through which the vertical airflow flows, Each of the heat detection units is connected to the substrate such that, when the inside of the cover is viewed from the bottom side, the heat sensing unit is located outside the substrate and the middle plate, and the heat sensing unit is located closer to the bottom side of the cover than the substrate and the middle plate. Thermal alarm.

2. a speaker provided in the main body portion and emitting sound; the intermediate plate is provided on the main body portion so as to cover the substrate and the speaker, and has a speaker hole provided opposite the speaker; The speaker hole in the middle plate is arranged so as not to overlap with the vertical hole and to be covered by the bottom surface. The thermal alarm of claim 1.

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