Appliance storage box for disaster prevention facility and acoustic device

Abstract

To provide an appliance storage box for a disaster prevention facility that increases sound pressure in front of a housing of a district bell housed in a housing of the appliance storage box, and thus can fully satisfy a sound pressure condition for a bell sound stipulated in the Fire Service Act.SOLUTION: In an appliance storage box for an anti-disaster facility which comprises: a gong type bell; a hammer disposed inside the bell main body of the bell and striking the inner surface of the bell main body to ring the bell; a driving source for the hammer; and a frame body having a front panel, in which the bell is disposed inside the frame body; and a sound hole is formed in a portion of the front panel that corresponds to the front of the bell, wherein: an outer-sided acoustic reflection wall having a shape that surrounds the bell main body is disposed near the bell main body, while being spaced apart from an external surface of the bell main body; and an inner-sided acoustic reflection wall having a predetermined size of gap and height is disposed inside the bell main body and between the wall and the inner surface of the bell main body.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to an equipment housing box and an acoustic device for disaster prevention equipment that are installed on the wall of a building to sound an alarm in the event of a fire, and in particular to technology that is effective when used for an equipment housing box and an acoustic device that are equipped with a gong-shaped bell. [Background technology]

[0002] Conventionally, a fire alarm system (fire alarm equipment) consisting of disaster prevention related equipment such as a fire transmitter (hereinafter simply referred to as a transmitter) and a signal light, and a fire receiver, has been installed inside a building to notify of the occurrence of a fire. The disaster prevention related equipment that constitutes the fire alarm system includes an equipment housing box that is installed on the wall of the building and has a transmitter, bell, speaker, and signal light on the front. An example of an invention related to an equipment housing box is described in Patent Document 1.

[0003] The equipment housing box is a disaster prevention device that houses a transmitter that alerts people to a fire by manually pressing a button, an indicator light that shows the location of the transmitter, and a district acoustic bell (district bell) that alerts people in the vicinity to a fire by sound in the event of a fire. The transmitter and indicator light are exposed on the surface of the housing of the equipment housing box, but the district bell is housed inside the housing of the equipment housing box, and when the district bell is activated, sound is emitted to the outside from numerous sound holes (sound outlets) opened in the housing panel in front of the bell. The bells used in the equipment housing box are often gong-type bells that are sounded by striking a small metal plate with a mechanical hammer. An example of an invention related to a gong-type bell is described in Patent Document 2. Furthermore, the Fire Service Act stipulates sound pressure requirements for district bells, and tests are conducted during firefighting equipment inspections to confirm that the sound pressure meets the specified requirements. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-102866 [Patent Document 2] Patent No. 3415518 Summary of the Invention [Problem to be solved by the invention]

[0005] As mentioned above, the district bell installed in the equipment housing box for disaster prevention equipment is installed inside the housing, so the panels and various parts that make up the housing of the equipment housing are arranged in front of and around the district bell. As a result, there is a tendency for these parts or the installation conditions to hinder the emission of the bell sound, which creates the problem of the risk of not being able to obtain sufficient sound pressure as stipulated by the Fire Service Act. In addition, the invention of the equipment housing box described in Patent Document 1 states that an acoustic reflector is provided to surround or sandwich the bell, but since the detailed shape and structure of the acoustic reflector, the positional relationship of the belt, etc. are not disclosed, it may not be possible to obtain sufficient sound pressure.

[0006] The present invention has been made with an eye on the above-mentioned problems, and its purpose is to provide an equipment storage box and an acoustic device for disaster prevention equipment that can increase the sound pressure in front of the housing of the district bell that is housed within the housing of the equipment storage box, thereby fully meeting the sound pressure requirements for bell sounds stipulated in the Fire Service Act. [Means for solving the problem]

[0007] In order to solve the above problems, the present invention provides: A disaster prevention equipment storage box includes a gong-shaped bell, a hammer disposed inside the bell body (gong) of the bell and striking the inner surface of the bell body to sound it, a drive source for the hammer, and a frame having a front panel, the bell being disposed inside the frame, and an acoustic hole being formed in a portion of the front panel corresponding to the front of the bell, An outer acoustic reflection wall is disposed near the bell body (gong) and has a shape that surrounds the bell body while being spaced apart from the outer surface of the bell body. An inner acoustic reflection wall is disposed inside the bell body (gong), with a predetermined distance and height between it and the inner surface of the bell body.

[0008] With the equipment housing box configured as described above, the sound emitted from the inner surface of the bell body (gong) hits the inner acoustic reflection wall, reflects off, and is emitted forward through the gap between the outer surface of the bell body (gong) and the outer acoustic reflection wall, thereby increasing the sound pressure in front of the housing of the district bell housed within the equipment housing box, thereby fully meeting the sound pressure requirements for bell sounds stipulated in the Fire Service Act.

[0009] Preferably, the inner acoustic reflection wall has a cylindrical shape or a partial cylindrical shape, or a conical cylindrical shape or a partial conical cylindrical shape. The inner acoustic reflection wall may be curved along the axial direction. With this configuration, the sound emitted from the inner surface of the bell body (gong) can be reflected forward, and the inner acoustic reflection wall has a simple shape, making it easy to manufacture and reducing parts costs.

[0010] Preferably, the inner sound reflecting wall has a hole or a notch formed in a portion corresponding to the hammer. With this configuration, even if the distance between the bell body (gong) and the inner acoustic reflection wall is reduced, interference between the hammer and the inner acoustic reflection wall can be prevented, and the configuration allows for easy arrangement of both.

[0011] Furthermore, preferably, the drive source is accommodated in a housing, The housing is disposed inside the bell body (gong) and is formed to have a concentric wall shape that can form a predetermined gap between itself and the inner surface of the bell body, thereby functioning as the inner acoustic reflection wall. With this configuration, the peripheral wall of the housing that houses the hammer drive source functions as the inner sound reflecting wall, so there is no need to provide the housing and the inner sound reflecting wall separately, thereby reducing the number of parts.

[0012] Preferably, the outer acoustic reflection wall has a cylindrical shape with a bottom, and the bottom wall is formed so that the central portion thereof has a step that bulges forward. This configuration allows for greater freedom in designing the distance between the outer acoustic reflection wall and the inner acoustic reflection wall, making it possible to more efficiently guide the sound emitted from the inner surface of the bell body (gong) forward.

[0013] Another invention of the present application is an acoustic device for disaster prevention equipment, which includes a gong-shaped bell, a hammer disposed inside the bell body of the bell and striking the inner surface of the bell body to make it ring, a drive source for the hammer, and a housing for accommodating the drive source. The housing is disposed inside the bell body and is formed to have a concentric wall shape that can form a predetermined gap between itself and the inner surface of the bell body, thereby functioning as an inner acoustic reflection wall.

[0014] With the acoustic device configured as described above, the sound emitted from the inside of the bell body (gong) hits the housing that contains the drive source, reflects off, and is emitted forward through the gap between the housing and the bell body (gong), thereby increasing the sound pressure of the district bell ringing in front of the device and fully meeting the sound pressure requirements for bell sounds stipulated in the Fire Service Act. [Effects of the Invention]

[0015] The sound pressure level of the bell ringing sound generated by the sound device according to the present invention can be increased in front of the device, thereby satisfying the requirements for the sound pressure of the bell sound stipulated in the Fire Service Act. [Brief explanation of the drawings]

[0016] [Figure 1] 1A is a front view showing one embodiment of a device housing box for disaster prevention equipment according to the present invention, and FIG. 1B is a side view thereof. [Figure 2] 2A is a plan perspective view showing an example of the configuration of a bell in the equipment housing box of the embodiment of FIG. 1, and FIG. 2B is a front cross-sectional view thereof. [Figure 3] FIG. 1A is an enlarged explanatory diagram of a main part showing an image of sound transmission in a conventional gong-type bell, and FIG. 1B is an enlarged explanatory diagram of a main part showing an image of sound transmission in a bell according to an embodiment of the present invention. [Figure 4] 3A and 3B show a first modification of the bell of the embodiment shown in FIG. 2, in which (A) is a plan perspective view of the bell and (B) is a front cross-sectional view thereof. [Figure 5] 3 shows a second modification of the bell of the embodiment shown in FIG. 2, where (A) is a plan perspective view of the bell and (B) is a front cross-sectional view thereof. [Figure 6] 10A and 10B are enlarged cross-sectional views of essential parts showing other modified inner acoustic reflection walls in the bell of the embodiment. [Figure 7] 10A and 10B are enlarged cross-sectional views of essential parts showing other modified examples of the outer acoustic reflection wall of the bell of the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0017] An embodiment of an equipment housing box for disaster prevention equipment (hereinafter simply referred to as equipment housing box) to which the present invention is applied will be described below with reference to the drawings, but first the configuration of the equipment housing box of this embodiment will be described with reference to Fig. 1. Fig. 1(A) is a front view of the equipment housing box of this embodiment, and Fig. 1(B) is a side view thereof. As shown in FIG. 1, the equipment housing box 10 of this embodiment includes a housing 14 having a front panel 14a on the front of which is provided a bullet-shaped indicator light 11, a sound hole 12 for a district bell, and a transmitter 13, and the housing 14 is fixed to a wall surface 20 of a building.

[0018] Inside the housing 14, a district bell 15 is arranged at a position corresponding to the acoustic hole 12, and the district bell 15 is arranged in a state of being stored in a storage box 16, and the storage box 16 is fixed to a chassis 17 provided inside the housing 14. It should be noted that components other than the storage box 16 may be attached to the chassis 17.

[0019] 2 shows an example of the configuration of the district bell 15 in the equipment housing box 10 of this embodiment. In this figure, (A) is a perspective view of the district bell 15 seen from above, and (B) is a front cross-sectional view showing the internal structure. As shown in Figure 2(B), the gong-shaped bell comprises a gong 51, which serves as the metal bell body shaped like an upside-down deep bowl; a rod 52, one end of which is connected to the center of the inner surface of gong 51 and supports gong 51; a hammer 53, which strikes gong 51 to make it sound; and a hammer drive unit 54, which consists of a motor, cam, etc., that drives hammer 53.

[0020] In addition, the district bell 15 of this embodiment is configured to have a storage box 16 as a cylindrical outer sound-reflecting wall with a bottom and a diameter slightly larger than that of the gong 51, as well as a cylindrical inner sound-reflecting wall 55 with a diameter slightly smaller than that of the gong 51. This creates spaces 56a, 56b, and 56c of predetermined dimensions to increase the sound pressure in front of the bell between the gong 51 and the outer acoustic reflection wall (16) and between the gong 51 and the inner acoustic reflection wall 55. Reference numeral 16a denotes a flange portion provided at the front end of the storage box 16, and this flange portion 16a is joined to the front edge of the housing 14 or the back surface of the front panel 14a.

[0021] 2 uses a rod-shaped object (a striker) as hammer 53, which is repeatedly moved back and forth in the axial direction to strike the inner surface of gong 51 and sound the hammer. Specifically, although not shown, hammer drive unit 54 is provided with a motor as a drive source and a crank mechanism, and the rotation of the motor is converted by the crank mechanism into the reciprocating movement of rod-shaped hammer 53, thereby driving hammer 53.

[0022] In Figure 3(B), arrows are used to illustrate the transmission of sound generated in the district bell 15 of this embodiment. For comparison, arrows are used in Figure 3(A) to illustrate the transmission of sound generated in a conventional, general gong-type bell such as that described in Patent Document 2. In conventional examples, the space corresponding to G1 shown in Figure 3(B) of Figure 3(A) was often narrowed to prevent sound from the inside of the gong (bell body) from escaping to the outside. Furthermore, Figure 3(B) does not show all of the transmission paths of the bell sound. Because sound is a wave, it is not only transmitted in a straight line as shown by the arrow in Figure 3(B), but also transmitted around the edge of the gong 51 due to diffraction. However, this is not shown in order to avoid complicating the illustration.

[0023] As shown in Figure 2, the district bell 15 of this embodiment is configured to have an outer sound-reflecting wall (16) and an inner sound-reflecting wall 55, whereas a conventional gong-type bell only has a single cylindrical storage box 16 with a bottom that is slightly larger in diameter than the gong 51, and the gap G1 shown in Figure 3(B) is also set small, so that the storage box 16 functions as a sound-reflecting wall. Therefore, in conventional bells, as shown in Figure 3(A), sound emitted from the outside of the gong 51 is reflected either directly or by hitting the reflecting wall (16) and is emitted outward (upward in the figure) from the opening, but most of the sound emitted from the inside of the gong 51 hits the hammer drive unit 54 and is reflected back toward the inside of the gong 51, becoming trapped inside the gong 51 and attenuating as it repeatedly reflects off the inside of the reflecting wall (16), resulting in insufficient sound pressure being generated at the front of the bell.

[0024] In contrast, in the district bell 15 of this embodiment, as shown in Fig. 3(B), part of the sound emitted from the inner surface of the gong 51 hits the outer surface of the inner acoustic reflection wall 55 and is reflected toward the bottom wall of the outer reflection wall (16).The sound is then reflected by the inner surfaces of the bottom wall and peripheral wall of the outer reflection wall (16) and is emitted outward through the opening.As a result, the sound pressure in front of the equipment housing box 10 can be increased compared to the bell with the conventional structure shown in Fig. 3(A). The optimum values ​​for the mounting position (diameter) and height of the inner sound reflecting wall 55 may be determined by experiments and simulations performed by changing the dimensions of the components. The same applies to the shape of the inner sound reflecting wall 55.

[0025] For example, the sounds generated on the outer and inner surfaces of gong 51 are 180° out of phase (out of phase), so when the two sounds overlap, they cancel each other out and cause significant attenuation, whereas when the sounds generated on the outer and inner surfaces overlap in phase, the amplitude increases. In conventional bells, the sound generated on the inner surface of the gong is less likely to reach the outer surface, so the sounds generated on the outer and inner surfaces do not overlap, and so it is thought that there is little attenuation of the sound in front of the gong. In contrast to this, by providing an inner acoustic reflection wall 55 as in the district bell 15 of this embodiment, the sound emitted from the inside of the gong, reflected by the inner acoustic reflection wall 55, and guided forward can be made to approach the same phase as the sound emitted from the outside of the gong by adjusting the distance and shape of the inner acoustic reflection wall 55, which is thought to result in a greater sound pressure.

[0026] However, the optimum distance between the gong 51 and the inner acoustic reflection wall 55 varies depending on the frequency of the sound generated by the gong 51. Furthermore, as the frequency band of the sound generated by the gong becomes wider, it becomes more difficult to determine the distance between the inner acoustic reflection wall 55 and the gong 51 so that the sounds are close to in-phase. Therefore, the shape and material of the gong can be selected to narrow the frequency band of the generated sound, or the frequency with the highest sound pressure within the frequency band of the generated sound can be found and the height of the inner acoustic reflecting wall 55 and the distance between the reflecting wall 55 and the gong 51 (dimensions H1, H2, L, G1, and G2 shown in Figure 3(B)) can be set to bring the sound closest to the in-phase at that frequency.

[0027] (Variation) Furthermore, since many district bells in disaster prevention monitoring systems are installed within a building, it is preferable that they consume as little current as possible. Therefore, it is desirable to design the motor, hammer, crank mechanism, and gong shape so that they can generate sound pressure that meets regulations while consuming as little current as possible. For example, Figure 2 shows the shape of the inner acoustic reflection wall 55 for a relatively small bell in which the hammer drive unit 54 is located near the center of the gong 51. Because the hammer drive unit 54 is relatively small, the inner acoustic reflection wall 55 is approximately cylindrical, with a hole or notch 55a formed in part of it so as not to interfere with the operation of the hammer 53. On the other hand, if the hammer drive unit 54 is relatively large and positioned off-center from the center of the gong 51, the inner acoustic reflection wall 55 will be shaped to avoid the hammer drive unit 54 by eliminating part of its cylindrical shape, as shown in Figure 4.

[0028] Figure 5 shows an example of a bell in which the housing of hammer drive unit 54 is shaped so that its outer wall also functions as an inner acoustic reflecting wall. As shown in Figure 5, if the distance, height, shape, etc. between housing 54a of hammer drive unit 54 and the inner periphery of gong 51 are appropriately designed, much of the sound emitted from the inside of gong 51 will hit the outer wall of housing 54a of hammer drive unit 54, be reflected toward the inner surface of outer reflecting wall 16, and then be reflected again by the inner surface of outer reflecting wall 16 before being emitted outward through the opening. The bell in Figure 5 can be configured as a standalone district bell without being housed in the equipment housing box 10. In this case, the chassis 17 functions as a mounting plate. The bell may also be mounted directly to a mounting surface such as a wall without using a mounting plate. Furthermore, the storage box 16 serving as an external acoustic reflection wall may be omitted.

[0029] Furthermore, the shape of the inner sound reflecting wall 55 may be set to a shape other than a cylinder, as shown in Fig. 6. Of these, Fig. 6(A) shows the inner sound reflecting wall 55 shaped like a conical cylinder with a gradually changing diameter, and Fig. 6(B) shows the inner sound reflecting wall 55 with a longitudinal cross section curved in the vertical direction to form an arc shape. In the district bells shown in Figures 6(A) and 6(B), the inclination and curvature of inner acoustic reflection wall 55 allow the sound emitted from the inside of gong 51 to be guided forward more efficiently. While the inclination angle θ of inner acoustic reflection wall 55 is shown as less than 90° in Figure 6(A), it can also be greater than 90°. It is recommended that optimal values ​​for the inclination angle θ and curvature, as well as the dimensions H1, H2, L, G1, and G2, be found through experimentation.

[0030] 7(A) and (B) show the bottom wall of the outer acoustic reflecting wall (storage box 16) whose shape has been changed from a flat plate to a shape with a step 16a in the center that bulges forward. Of these, Fig. 7(A) shows the bottom wall of the outer acoustic reflecting wall (16) with the step 16a located outside the inner acoustic reflecting wall 55, and Fig. 7(B) shows the bottom wall of the outer acoustic reflecting wall (16) with the step 16a located inside the inner acoustic reflecting wall 55. The district bells of Figures 7(A) and (B) allow greater freedom in designing the distance between the outer acoustic reflection wall (16) and the inner acoustic reflection wall (55), allowing the sound emitted from the inside of the gong 51 to be guided forward more efficiently. Even in this modification, it is recommended that optimal values ​​for the dimensions H1, H2, L, G1, and G2 be found through experimentation. It is also possible to combine the modifications of Figures 6(A) and 6(B) with the modifications of Figures 7(A) and 7(B).

[0031] Although the present invention has been described above based on the embodiments, the present invention is not limited to the above embodiments. For example, in the above embodiments, the storage box 16 that functions as the outer sound reflecting wall is formed into a cylindrical shape with a bottom, but it may be formed into a cylindrical shape without a bottom wall, a conical shape whose diameter increases toward the front, or a conical shape with a bottom wall and whose diameter increases toward the front.

[0032] In the above embodiment, it has been explained that hammer drive unit 54 is configured to rotate a motor via a crank mechanism to reciprocate rod-shaped hammer 53. However, hammer drive unit 54 may also be provided with a motor and cam, as well as a spring that urges the striking portion (tip) of hammer 53 to abut against the surface of gong 51, so that the motor and cam move the striking portion of rod-shaped hammer 53 away from gong 51 against the repulsive force of the spring, and the spring is then released, causing the striking portion to collide with the inner surface of gong 51 and sound.

[0033] Alternatively, hammer 53 may be a T-shaped object like a hammer, with a support rod having a striking head at the tip supported by an axis in the center so that it can swing, and the support rod may be rotated by a motor to cause the head to collide with the surface of gong 51, striking it and sounding the gong. Furthermore, in the above embodiment, the present invention has been described as being applied to an equipment housing box that constitutes a fire alarm system, but the present invention is not limited to equipment housing boxes and can also be used in emergency alarm equipment that has a similar configuration to an equipment housing box but that sends a signal to a different destination when a transmitter is operated to notify of a fire. The present invention may also be applied to an equipment housing box that houses a district bell alone, without installing a pilot light or transmitter. [Explanation of symbols]

[0034] 10 Equipment storage box 11 Indicator light 12 Acoustic Hole 13 Transmitter 14. Case 14a Front Panel 15 District Bell 16 Storage box (external acoustic reflection wall) 16a Step 17 chassis 51 Gong (bell body) 52 Rod 53 Hammer 54 Hammer drive unit 54a Housing 55 Inner acoustic reflective wall 55a notch 56a, 56b, 56c Space

Claims

1. A disaster prevention equipment storage box includes a gong-shaped bell, a hammer disposed inside the bell body of the bell and striking the inner surface of the bell body to sound it, a drive source for the hammer, and a frame having a front panel, the bell being disposed inside the frame, and an acoustic hole being formed in a portion of the front panel corresponding to the front of the bell, an outer acoustic reflection wall having a shape surrounding the bell body while being spaced apart from the outer surface of the bell body is disposed near the bell body, An equipment storage box for disaster prevention equipment, characterized in that an inner acoustic reflection wall having a predetermined distance and height between the inner surface of the bell body and the wall is arranged inside the bell body.

2. The equipment storage box for disaster prevention equipment according to claim 1, characterized in that the inner acoustic reflection wall is configured to have a cylindrical shape or a partial cylindrical shape, or a conical cylindrical shape or a partial conical cylindrical shape.

3. 3. The equipment storage box for disaster prevention equipment according to claim 2, wherein the inner sound reflection wall has a hole or a notch formed in a portion corresponding to the hammer.

4. The drive source is housed in a housing, The equipment storage box for disaster prevention equipment described in claim 1, characterized in that the housing is arranged inside the bell body and is formed to have a concentric wall shape that can form a predetermined gap between the housing and the inner surface of the bell body, thereby functioning as the inner acoustic reflection wall.

5. An equipment storage box for disaster prevention equipment as described in any one of claims 1 to 4, characterized in that the outer acoustic reflection wall is cylindrical with a bottom, and the bottom wall is formed so that the central part has a step that bulges forward.

6. An acoustic device for disaster prevention equipment, comprising: a gong-shaped bell; a hammer disposed inside a bell body of the bell and striking the inner surface of the bell body to sound the bell; a drive source for the hammer; and a housing for accommodating the drive source. An acoustic device for disaster prevention equipment, characterized in that the housing is arranged inside the bell body and is formed to have a concentric wall shape that can form a predetermined gap between the housing and the inner surface of the bell body, thereby functioning as an inner acoustic reflection wall.

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