Gas detecting device

Abstract

To provide a waterproof construction that can easily adjust a volume of sound output from an acoustic unit to an outside of a housing.SOLUTION: A gas detecting unit comprises: a housing having an opening portion; an internal cover 21 that closes the opening portion, in which a through hole is formed; a detection unit that detects a gas; an acoustic unit 16 that is provided inside the housing, and outputs a sound in response to a detection result of the gas; a main body portion 32 that is provided in the through hole; a head portion 33 that is fastened to the main body portion; a waterproof member 30 that closes the through hole; and a spacer member 40 provided between the main body portion 32 and the head portion 33. An acoustic passage 301 is formed in the waterproof member 30 so as to guide the sound output from the acoustic unit 16 to an outside of the housing.SELECTED DRAWING: Figure 10

Description

[Technical Field]

[0001] The present invention relates to a waterproof structure for a gas detection device. [Background technology]

[0002] Patent Document 1 describes that the sound pressure level of the buzzer sound from the alarm buzzer is increased by the action of a resonance space formed in the casing, and the sound is emitted to the outside through a buzzer sound emission opening. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 5818666 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the configuration described in Patent Document 1, the internal structure of the housing must be changed in order to adjust the volume of the sound output from the acoustic unit to the outside of the housing, and therefore it is not easy to adjust the volume of the sound output to the outside of the housing.

[0005] An object of the present invention is to provide a waterproof structure that allows for easy adjustment of the volume of sound output from an acoustic section to the outside of a housing. [Means for solving the problem]

[0006] One aspect of the present invention provides a gas detection device having a housing with an opening, an internal cover formed with a through hole and closing the opening, a detection unit for detecting gas, an acoustic unit provided inside the housing and outputting sound in response to the detection result of the gas, a main body provided in the through hole, and a head unit fastened to the main body, the gas detection device further comprising a waterproof member closing the through hole, and a spacer member provided between the main body and the head unit, the waterproof member having an acoustic passage formed therein for guiding the sound output from the acoustic unit to the outside of the housing. [Effects of the Invention]

[0007] According to the present invention, it is possible to provide a waterproof structure that can easily adjust the volume of sound output from the acoustic section to the outside of the housing. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 2 is a diagram illustrating an example of the electrical configuration of the gas detection device. [Figure 2] FIG. 2 is a side view illustrating an example of the appearance of the gas detection device. [Figure 3] FIG. 1 is a plan view illustrating an example of the appearance of a gas detection device. [Figure 4] An enlarged view of part A in Figure 3. [Figure 5] Side view of Figure 4. [Figure 6] FIG. 6 is an exploded perspective view of FIG. 5. [Figure 7] FIG. [Figure 8] FIG. [Figure 9] FIG. [Figure 10] FIG. 5 is a cross-sectional view taken along line II in FIG. [Figure 11] 10A and 10B are diagrams illustrating examples of the relationship between the thickness of a spacer member and the sound pressure of sound output from an acoustic unit to the outside of a housing. DETAILED DESCRIPTION OF THE INVENTION

[0009] (composition) Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the dimensions, shapes, and ratios of the drawings may differ from those of the actual ones in order to facilitate understanding of the invention.

[0010] 1 is a diagram illustrating the electrical configuration of gas detection device 1. Gas detection device 1 is used, for example, in the event of a disaster, to search for survivors among rubble and earth and sand. Gas detection device 1 detects gases emitted from the human body.

[0011] Gas detection device 1 includes control unit 11, memory unit 12, detection unit 13, operation unit 14, display unit 15, and audio unit 16. Control unit 11 is connected to memory unit 12, detection unit 13, operation unit 14, display unit 15, and audio unit 16 via a bus.

[0012] The control unit 11 controls each unit of the gas detection device 1 and performs various processes. The control unit 11 includes a processor such as a CPU. The storage unit 12 stores programs for implementing the functions of the gas detection device 1 and various data used in the processing of the control unit 11. The storage unit 12 includes memories such as RAM and EEPROM. The detection unit 13 is a gas sensor that detects the concentration of gases emitted from the human body. More specifically, the detection unit 13 detects carbon dioxide emitted from the collected air by a person's breathing and ammonia contained in the person's urine. Note that the detection unit 13 does not necessarily detect both carbon dioxide and ammonia; it may detect only one of carbon dioxide and ammonia. The operation unit 14 accepts operations for the gas detection device 1. The operation unit 14 includes, for example, an operation switch. The display unit 15 displays various information. The display unit 15 includes, for example, an LED, a 7-segment display, or a liquid crystal display. For example, the display unit 15 displays information indicating whether a person is present within the detection range according to the concentration of the gas detected by the detection unit 13. The acoustic unit 16 outputs an alarm sound. The acoustic unit 16 includes, for example, a buzzer. For example, the acoustic unit 16 outputs an alarm sound when it is determined based on the detection result of the detection unit 13 that there is a high possibility that a person is present within the detection range.

[0013] FIG. 2 is a side view illustrating the appearance of gas detection device 1. FIG. 3 is a plan view illustrating the appearance of gas detection device 1. Gas detection device 1 is used outdoors when carried using a shoulder strap (not shown) connected to housing 20. Housing 20 has a waterproof structure so that rescue operations can be carried out using gas detection device 1 even in rainy weather. However, simply sealing the inside of housing 20 makes it difficult to hear the sound output from acoustic unit 16 provided inside housing 20. Therefore, the waterproof structure of housing 20 according to this embodiment is designed to amplify the sound output from acoustic unit 16 while ensuring the waterproofness of housing 20.

[0014] Gas detection device 1 includes a housing 20, an inner cover 21, an operation panel 22, and a circuit board 23. When gas detection device 1 is used, a gas sampling rod that collects ambient air is connected to housing 20, but the gas sampling rod is not shown in Figures 2 and 3.

[0015] The housing 20 accommodates the control unit 11, storage unit 12, detection unit 13, operation unit 14, display unit 15, and audio unit 16. The housing 20 is made of resin and has a hollow, approximately rectangular parallelepiped shape. A bottom is provided at the lower end of the housing 20, and an opening 201 that is approximately rectangular in plan view is formed at the upper end of the housing 20.

[0016] The internal cover 21 closes the opening 201 of the housing 20. The internal cover 21 is a plate-like member that is substantially rectangular in plan view. The internal cover 21 is fixed to the housing 20 with a sealing member (not shown) sandwiched therebetween in order to seal the inside of the housing 20. The internal cover 21 has a circular through-hole 211 formed therein to allow the sound output from the acoustic unit 16 to be emitted to the outside. A waterproof member 30 is provided in the through-hole 211 to prevent water from entering the inside of the housing 20 through the through-hole 211 while ensuring sound permeability.

[0017] Operation panel 22 is used for operating and displaying gas detection device 1. Operation panel 22 is provided on top of inner cover 21. Operation panel 22 has a plurality of through holes formed therein, and operation unit 14, display unit 15, and waterproof member 30 are exposed to the outside through these through holes.

[0018] The circuit board 23 mounts electronic components such as the control unit 11 and the storage unit 12. The circuit board 23 is provided, for example, in the center of the housing 20. Because the circuit board 23 is separated from the opening 201, if the acoustic unit 16 were placed on the circuit board 23, the sound output from the acoustic unit 16 would be difficult to hear from the outside. Therefore, in this embodiment, the acoustic unit 16 is not placed on the circuit board 23.

[0019] Fig. 4 is an enlarged view of portion A in Fig. 3. Fig. 5 is a side view of Fig. 4. Fig. 6 is an exploded perspective view of Fig. 5. Housing 20 and operation panel 22 are omitted from Figs. 4 to 6. Gas detection device 1 includes waterproof member 30, spacer member 40, and holder 50.

[0020] The waterproof member 30 closes the through-hole 211 from the outside of the housing 20 so as to ensure both waterproofness and sound permeability. The waterproof member 30 has an acoustic passage 301 formed therein that guides the sound output from the acoustic unit 16 to the outside of the housing 20. As shown in FIG. 6 , the waterproof member 30 has an elastic portion 31, a main body portion 32, and a head portion 33.

[0021] The elastic portion 31 serves to prevent water from entering. The elastic portion 31 is a cylindrical member made of an elastic, waterproof material such as rubber. The elastic portion 31 is provided between the head portion 33 and the main body portion 32, and is compressed by the head portion 33.

[0022] FIG. 7 is a plan view illustrating the elastic portion 31. Nine through holes 311 that form part of the acoustic path 301 are formed in the elastic portion 31. Each through hole 311 has a cylindrical shape and penetrates in the height direction. One of the nine through holes 311 is provided in the center of the elastic portion 31 in a plan view. This through hole 311 has a larger diameter than the other through holes 311. The remaining eight through holes 311 are arranged around the central through hole 311. More specifically, the remaining eight through holes 311 are arranged at equal intervals on a circumference of a circle that has the same center as the central through hole 311 and a larger radius. The through holes 311 are an example of a second through hole according to the present invention.

[0023] As shown in FIG. 6 , the elastic portion 31 has a filter 312. The filter 312 is, for example, a vent filter, and is waterproof and breathable, allowing air to pass through but not water. Being waterproof and breathable means having the ability to prevent water from entering and the ability to allow air to pass through. However, the filter 312 does not have to completely prevent water from entering; it is sufficient if it can prevent water from entering to a certain extent. Furthermore, the filter 312 may have a low air flow rate as long as it allows air to pass through. The filter 312 is welded to or integrally molded with the elastic portion 31 so as to block the through-hole 311 inside the elastic portion 31.

[0024] The main body 32 is provided in and fixed to the through hole 211. The main body 32 has a base 35, a recess 36, and a protrusion 37. The base 35 is a seat for the main body 32. The base 35 is a plate-like member that is approximately hexagonal in a plan view. The protrusion 37 is used to fix the main body 32 to the upper surface of the inner cover 21. The protrusion 37 has a cylindrical shape and is provided on the lower surface of the base 35. The diameter of the protrusion 37 is smaller than the diameter of the through hole 211. The protrusion 37 is inserted into the through hole 211 with a seal member 38 sandwiched between the base 35 and the inner cover 21. A male thread is formed on the outer peripheral surface of the protrusion 37.

[0025] The retaining portion 50 secures the main body 32 to the inner cover 21 and holds the acoustic unit 16 on the underside of the inner cover 21. The retaining portion 50 has a cylindrical shape. A recess 51 is formed at the upper end of the retaining portion 50, and a bottom is provided at the lower end of the retaining portion 50. An internal thread is formed on the inner circumferential surface of the retaining portion 50 to mate with an external thread formed on the outer circumferential surface of the protrusion 37. The retaining portion 50 is fastened to the protrusion 37 by being screwed into the protrusion 37. Because the base 35 is larger than the through hole 211, the base 35 remains on the inner cover 21 even when the protrusion 37 is inserted into the through hole 211. Therefore, when the retaining portion 50 is fastened to the protrusion 37, the seal member 38 and the inner cover 21 are sandwiched between the base 35 and the retaining portion 50. The main body 32 is then fixed to the inner cover 21 with the seal member 38 sandwiched between them. This ensures waterproofing.

[0026] Furthermore, a recess 371 into which a portion of the acoustic unit 16 is inserted is formed on the bottom surface of the protrusion 37 of the main body 32. The acoustic unit 16 has a cylindrical shape, and a protrusion 161 is provided on the top surface of the acoustic unit 16. The protrusion 161 is inserted into the recess 371. As a result, the acoustic unit 16 is positioned inside the housing 20 at a position that overlaps with the through-hole 211 in a plan view.

[0027] A recess 51 for accommodating the acoustic unit 16 is formed on the upper surface of the holding unit 50. With the acoustic unit 16 accommodated in the recess 51, the holding unit 50 is fastened to the protrusion 37, thereby holding the acoustic unit 16 on the lower surface of the inner cover 21. Since the acoustic unit 16 is provided away from the circuit board 23, the acoustic unit 16 and the circuit board 23 are connected via a signal line 162. A wiring hole (not shown) for passing the signal line 162 is formed in the bottom of the holding unit 50.

[0028] 8 is a plan view illustrating the main body 32. Four through holes 351 that form part of the acoustic path 301 are formed in the base 35. Each through hole 351 has a fan shape and penetrates in the height direction. The four through holes 351 are arranged radially adjacent to each other at intervals in the center of the base 35. The through holes 351 are an example of a first through hole according to the present invention.

[0029] The recess 36 accommodates the elastic portion 31. The recess 36 is composed of four peripheral walls 361. Each peripheral wall 361 protrudes upward from the upper surface of the base 35. The four peripheral walls 361 are arranged at equal intervals on the outer periphery of an area on the upper surface of the base 35 that overlaps with the elastic portion 31 in a plan view. The elastic portion 31 is inserted inside the four peripheral walls 361. A slit 362 that forms part of the acoustic path 301 is formed between adjacent peripheral walls 361. The slit 362 is formed along the height direction of the peripheral wall 361. In addition, a male thread is formed on the outer periphery of the peripheral wall 361 to fasten the head portion 33. A step 363 that supports the spacer member 40 from below is provided at the lower end of the outer periphery of each peripheral wall 361.

[0030] Returning to FIG. 6 , the head portion 33 is fastened to the main body portion 32 by compressing the elastic portion 31. The head portion 33 has a hollow cylindrical shape. A top wall portion is provided at the upper end of the head portion 33, and the lower end is open. However, to make it easier to turn the head portion 33, the outer peripheral surface of the head portion 33 is generally hexagonal in plan view. The inner peripheral surface of the head portion 33 is formed with a female thread that mates with a male thread formed on the outer peripheral surface of the peripheral wall 361. The head portion 33 is fastened to the main body portion 32 by being screwed into the peripheral wall 361.

[0031] FIG. 9 is a bottom view illustrating the head portion 33. The head portion 33 is provided with six protrusions 331 that press against the elastic portion 31. Each protrusion 331 protrudes downward from the underside of the top wall portion. The six protrusions 331 are arranged at equal intervals on the inner periphery of the area of ​​the top wall portion of the head portion 33 that overlaps with the elastic portion 31 in a plan view. When the head portion 33 is fastened to the main body portion 32 with the elastic portion 31 sandwiched therebetween, the elastic portion 31 is pressed and compressed by the protrusions 331 of the head portion 33. This ensures waterproofing. Gaps 332 that form part of the acoustic path 301 are formed between adjacent protrusions 331. Each gap 332 is formed along the height direction of the protrusions 331.

[0032] Returning to FIG. 6 , the spacer member 40 is used to prevent loosening of the head portion 33 and the main body portion 32 and to adjust the volume of the sound output from the acoustic unit 16 to the outside of the housing 20. The spacer member 40 is, for example, a resin washer, has a ring shape, and is provided between the head portion 33 and the step portion 363. The inner diameter of the spacer member 40 is larger than the diameter of the circumscribed circle of the four peripheral walls 361 and smaller than the diameter of the circumscribed circle of the four step portions 363. The spacer member 40 has a thickness that ensures that the sound output from the acoustic unit 16 to the outside of the housing 20 is at or above a predetermined sound pressure. The sound pressure of the sound output from the acoustic unit 16 to the outside of the housing 20 varies depending on the size of the acoustic path 301. If the acoustic path 301 has a size corresponding to the resonant frequency of the sound output from the acoustic unit 16 to the outside of the housing 20, the sound output from the acoustic unit 16 to the outside of the housing 20 is amplified, resulting in a higher sound pressure. The size of the acoustic path 301 varies depending on the thickness of the spacer member 40.

[0033] 10 is a cross-sectional view taken along line II in FIG. 4. The acoustic path 301 is formed by the through-hole 351 in the base 35, the through-hole 311 in the elastic portion 31, the gap 332 in the head portion 33, and the slit 362 in the recess 36. When the head portion 33 is fastened to the main body 32, the elastic portion 31 is pressed by the protrusion 331 of the head portion 33. Since the elastic portion 31 does not contact the top wall portion of the head portion 33 when the head portion 33 is fastened to the main body 32, a gap 332 extending in the radial direction of the head portion 33 is formed between the top wall portion and the elastic portion 31. The slit 362 also forms a gap extending in the height direction between the elastic portion 31 and the inner circumferential surface of the head portion 33 and between the elastic portion 31 and the spacer member 40. This gap and the gap 332 described above are examples of a first gap according to the present invention. Furthermore, since the spacer member 40 is provided overlapping the step portion 363, a gap equal to the height of the step portion 363 is formed between the upper surface of the base portion 35 and the spacer member 40 at the slit 362. This gap serves as the outlet of the acoustic path 301. This gap is an example of a second gap according to the present invention. The sound output from the acoustic unit 16 passes through the acoustic path 301 and is output to the outside of the housing 20.

[0034] For example, if the spacer member 40 becomes thicker, the distance between the head portion 33 and the main body portion 32 becomes larger, and the force with which the head portion 33 compresses the elastic portion 31 becomes weaker. If the force compressing the elastic portion 31 becomes weaker, the elastic portion 31 extends in the height direction, and accordingly, the acoustic path 301 also becomes longer in the height direction. Conversely, if the spacer member 40 becomes thinner, the distance between the head portion 33 and the main body portion 32 becomes smaller, and the force with which the head portion 33 compresses the elastic portion 31 becomes stronger. If the force compressing the elastic portion 31 becomes stronger, the elastic portion 31 contracts in the height direction, and accordingly, the acoustic path 301 also becomes shorter in the height direction. If the size of the acoustic path 301 changes, the sound pressure of the sound output from the acoustic unit 16 to the outside of the housing 20 changes.

[0035] FIG. 11 is a diagram illustrating the relationship between the thickness of the spacer member 40 and the sound pressure of the sound output from the acoustic unit 16 to the outside of the housing 20. In FIG. 11, the horizontal axis represents the thickness [mm] of the spacer member 40, and the vertical axis represents the sound pressure [dB] of the sound output from the acoustic unit 16 to the outside of the housing 20. In the example of FIG. 11, when the thickness of the spacer member 40 is 0 mm, 1 mm, 1.5 mm, 2 mm, 2.5 mm, and 5 mm, the sound pressure of the sound output from the acoustic unit 16 to the outside of the housing 20 is approximately 61 dB, approximately 71 dB, approximately 72 dB, approximately 70 dB, approximately 68 dB, and approximately 63 dB, respectively. A thickness of 0 mm for the spacer member 40 indicates that the spacer member 40 is not provided. A thickness of 5 mm for the spacer member 40 indicates that the head portion 33 is not provided, i.e., the height of the gap serving as the outlet of the acoustic path 301 is at its maximum.

[0036] When the thickness of the spacer member 40 is approximately 1 mm or more and 2 mm or less, the sound pressure is 70 dB or more. This means that when the thickness of the spacer member 40 is 1 mm or more and 2 mm or less, resonance is likely to occur in the acoustic path 301 at the frequency of the sound output from the acoustic unit 16. Furthermore, when the thickness of the spacer member 40 is 1.5 mm, the sound pressure is maximized. This means that when the thickness of the spacer member 40 is 1.5 mm, resonance is most likely to occur in the acoustic path 301 at the frequency of the sound output from the acoustic unit 16. For example, if the sound pressure of the sound output from the acoustic unit 16 to the outside of the housing 20 is desired to be 70 dB or more, the thickness of the spacer member 40 is determined to be 1 mm or more and 2 mm or less. By using a spacer member 40 with the determined thickness, the sound pressure of the sound output from the acoustic unit 16 to the outside of the housing 20 can be adjusted to 70 dB or more.

[0037] According to the embodiment described above, by changing the thickness of the spacer member 40, it is possible to easily adjust the sound pressure of the sound output from the acoustic unit 16 to the outside of the housing 20 so that it is increased. Also, since a filter 312 is provided in the through hole 311 of the elastic unit 31, it is possible to prevent water from entering through the acoustic passage 301. Furthermore, since the acoustic unit 16 is provided not on the circuit board 23 but on the underside of the inner cover 21, which is closer to the opening 201 of the housing 20 than the circuit board 23, it is possible to increase the sound output from the acoustic unit 16 to the outside of the housing 20 compared to when the acoustic unit 16 is provided on the circuit board 23.

[0038] (Variation) The present invention is not limited to the above-described embodiment. The above-described embodiment may be modified as in the following modified examples. Two or more of the following modified examples may be used in combination. The embodiment and one or more modified examples may be used in combination, or may be switched depending on the implementation.

[0039] In the above-described embodiment, gas detection device 1 is not limited to detecting gases emitted from the human body. Gas detection device 1 may also detect dangerous gases such as carbon monoxide gas and hydrogen sulfide gas generated at construction sites, tunnels, etc., and output an alarm sound.

[0040] In the above-described embodiment, the structure and arrangement of gas detection device 1 are merely examples and are not limited to these. For example, the shapes of elastic portion 31, main body portion 32, head portion 33, and spacer member 40 may be different from those described in the embodiment. A plurality of spacer members 40 may be provided. The number of through holes 351, through holes 311, peripheral walls 361, gaps 332, slits 362, and protrusions 331 may be more or less than those described in the embodiment. [Explanation of symbols]

[0041] 1: gas detection device, 11: control unit, 12: memory unit, 13: detection unit, 14: operation unit, 15: display unit, 16: acoustic unit, 20: housing, 21: inner cover, 22: operation panel, 23: circuit board, 30: waterproof member, 31: elastic member, 32: main body, 33: head, 35: base, 36: recess, 37: protrusion, 38: sealing member, 40: spacer member, 50: holding unit, 201: opening, 211: through hole, 301: acoustic passage, 311: through hole, 312: filter, 331: protrusion, 332: gap, 351: through hole, 361: peripheral wall, 362: slit, 363: step, 371: recess

Claims

1. a housing having an opening; an inner cover having a through hole formed therein and closing the opening; a detection unit for detecting a gas; an acoustic unit provided inside the housing and configured to output a sound in response to a result of the gas detection; a waterproofing member having a main body provided in the through hole and a head fastened to the main body, the waterproofing member closing the through hole; a spacer member provided between the main body and the head, The waterproof member has an acoustic passage formed therein that guides the sound output from the acoustic unit to the outside of the housing. Gas detection equipment.

2. The spacer member has a thickness that makes the sound output from the acoustic unit to the outside of the housing have a predetermined sound pressure or more.

2. The gas detection device according to claim 1.

3. the waterproof member has an elastic portion made of a waterproof material and provided between the main body portion and the head portion, the elastic portion being compressed by the head portion, The elastic portion has a waterproof and breathable filter provided in the acoustic passage.

3. The gas detection device according to claim 1 or 2.

4. The main body portion is formed with a first through hole that constitutes the acoustic passage, The elastic portion is formed with a second through hole that constitutes the acoustic passage, a first gap that constitutes the acoustic path is formed between the head portion and the elastic portion, and between the spacer member and the elastic portion; A second gap serving as an outlet of the acoustic passage is formed between the main body and the spacer member.

4. The gas detection device according to claim 3.

5. the main body portion has a recess into which a part of the acoustic portion is inserted, a holding portion for holding the acoustic portion inserted into the recess 2. The gas detection device according to claim 1.

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