Wind noise reduction device, handrail, and lattice structure

Abstract

To provide a wind noise reduction device that is easy to install on a banister and capable of reducing wind noise, the banister on which the wind noise reduction device is attached, and the grate-like structure provided with the banister.SOLUTION: A wind noise reduction device 14 is provided with a pair of plate members 22, a plurality of spring members 24 placed between both of plate members 22 in those lengthwise direction with an interval to each other and fixed on both of the plate members 22. The plurality of spring members 24 exert pressing force on both of the plate members 22 to allow the plate members 22 and the inner wall surface 12e to move relatively to each other upon deformation of the banister 12 by always contacting a whole surface of each of contact surfaces 22a of both of the plate members 22 on the inner surface 12e.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention is directed to reducing the magnitude of solid sound (hereinafter referred to as wind noise) generated when a lattice-like structure composed of handrails installed on windows, balconies, verandas, rooftops, emergency stairs, etc. of a building or fences installed at the boundaries of land, houses, etc. is subjected to wind.

Background Art

[0002] The lattice-like structures described above are provided with a plurality of handrails arranged at intervals and extending linearly vertically, horizontally, or diagonally. Wind noise occurs when the dominant vibration frequency of the Karman vortex generated when the wind blows through between the handrails of the lattice-like structure coincides with the natural vibration frequency of the handrails, or when the dominant vibration frequency of the Karman vortex is close to the natural vibration frequency of the handrails, due to a resonance phenomenon (vortex excitation).

[0003] As a technique for reducing the magnitude of wind noise in a vertical lattice handrail, which is one of the lattice-like structures, Patent Document 1 discloses a wind noise reduction structure provided with a plate member fixed to the surface or inside of the handrail. In this wind noise reduction structure, the energy for vibrating the handrail by wind pressure is reduced compared to the case where the plate member is not installed, so that vibration can be suppressed. As a result, the magnitude of wind noise caused by the vibration of the handrail is reduced.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the technology described in Patent Document 1 above, the plate member is fixed to the balusters using fasteners such as tapping screws and rivets, or by adhesives, welding, etc. Therefore, especially when fixing the plate member inside the balusters, it is difficult to install the plate member on the balusters because work must be done in a confined space.

[0006] The present invention has been made in view of the above, and aims to provide a wind noise reduction device that can be easily installed on the balusters of a grid-like structure and can reduce wind noise, a balusters to which the wind noise reduction device is attached, and a grid-like structure equipped with balusters. [Means for solving the problem]

[0007] To achieve the above objective, the wind noise reduction device of the present invention is a wind noise reduction device applied to a grid-like structure consisting of a handrail or fence having a plurality of hollow balusters having a rectangular cross-sectional shape, comprising a pair of opposing plate members arranged inside each baluster and extending in the extension direction of the baluster inside the baluster, and a plurality of elastic bodies arranged between the two plate members at intervals from each other in the longitudinal direction of the two plate members and fixed to the two plate members, wherein the plurality of elastic bodies exert a pressing force on the two plate members such that the entire surface of each plate member that contacts the inner wall surface of the baluster is always in contact with the inner wall surface, and when the baluster is deformed, the plate members and the inner wall surface are able to move relative to each other.

[0008] The balusters of the present invention are used in the manufacture of a lattice structure consisting of a handrail or fence, and comprise a tubular member having a rectangular cross-sectional shape and the wind noise reduction device of the present invention described above, which is disposed inside the tubular member.

[0009] The lattice structure of the present invention is a lattice structure comprising a handrail or fence having a plurality of balusters, wherein each baluster is made of the baluster of the present invention as described above. [Effects of the Invention]

[0010] According to the present invention, it is possible to provide a wind noise reduction device that can be easily installed on the balusters of a grid-like structure and can reduce wind noise, a balusters to which the wind noise reduction device is attached, and a grid-like structure equipped with balusters. [Brief explanation of the drawing]

[0011] [Figure 1] This is a perspective view of a vertical lattice handrail, which is one of the lattice structures according to the present invention. [Figure 2] This is a schematic longitudinal cross-sectional view showing a wind noise reduction device and a baluster to which the wind noise reduction device is attached. [Figure 3] Figure 2 is a plan view of the wind noise reduction device and the handrail. [Figure 4] (a) is a schematic longitudinal cross-section of the balusters and the wind noise reduction device inside them when there is no vibration. (b) is a schematic longitudinal cross-section of the balusters and the wind noise reduction device inside them when there is vibration in the first vibration mode. (c) is a schematic longitudinal cross-section of the balusters and the wind noise reduction device inside them when there is vibration in the second vibration mode. (d) is a schematic longitudinal cross-section of the balusters and the wind noise reduction device inside them when there is vibration in the third vibration mode. [Figure 5] This is an explanatory diagram of the contact pressure between the inner wall surface of the baluster and the contact surface of the plate member. [Figure 6] This figure shows the results of the hammering test. [Figure 7] This figure shows the results of the hammering test. [Figure 8] This figure shows the slip ratio in the vibration of the first vibration mode. [Figure 9] This figure shows the slip ratio in the vibration of the second vibration mode. [Figure 10] This figure shows the slip ratio in vibrations of the third vibration mode. [Figure 11] This diagram schematically shows the relationship between the contact pressure and the sliding ratio between the inner wall surface of the baluster and the contact surface of the plate member. [Figure 12] This figure shows the results of wind tunnel experiments. [Figure 13] This figure shows the results of wind tunnel experiments. [Figure 14] It is a figure showing the results of a wind tunnel experiment. [Figure 15] It is a figure showing the results of a wind tunnel experiment. [Figure 16] It is a figure showing the results of a wind tunnel experiment. [Figure 17] It is a figure showing the results of a wind tunnel experiment. [Figure 18] It is a figure showing the results of a wind tunnel experiment. [Figure 19] It is a figure showing the results of a wind tunnel experiment.

Embodiments for Carrying out the Invention

[0012] The present invention is directed to reducing wind noise of a lattice - like structure composed of handrails (vertical lattice handrails, horizontal lattice handrails, diagonal lattice handrails, etc.) installed on building windows, verandas, balconies, rooftops, emergency stairs, etc., or fences installed at the boundaries of land, houses, etc.

[0013] As shown in FIG. 1, a vertical lattice handrail 10, which is an example of a lattice - like structure to which the present invention is applied, includes a plurality of handrail members 12 and wind noise reduction devices 14 (FIGS. 2 and 3) attached to each handrail member 12.

[0014] The illustrated vertical lattice handrail 10 includes a pair of columns 16 extending in the vertical direction (up - down direction) and two upper and lower chord members 18 fixed to both columns 16 and extending in the horizontal direction. The plurality of handrail members 12 are arranged at intervals between both chord members 18 and extend in the vertical direction. Each handrail member 12, each column 16, and each chord member 18 are made of, for example, aluminum extrusion profiles.

[0015] As shown in FIGS. 2 and 3, the handrail 12 is composed of a hollow, i.e., tubular, member having a rectangular cross-sectional shape. The handrail 12 has upper and lower ends 12a and 12b that face each other, and is fixed to the upper and lower chord members 18 at the upper and lower ends 12a and 12b. Further, the handrail 12 has two pairs of outer wall surfaces (outer surfaces) 12c and 12d that face each other, and two pairs of inner wall surfaces (inner surfaces) 12e and 12f that face each other (see FIGS. 2 and 3). One pair of outer wall surfaces 12c of the handrail 12 faces the adjacent handrail 12 or the column 16. The other pair of outer wall surfaces 12d face the front side and the back side of the vertical lattice handrail 10, respectively.

[0016] The wind noise reduction device 14 includes a pair of plate members 22 that are arranged inside the handrail 12 and face each other, and a plurality (three in the illustrated example) of spring members (corresponding to elastic bodies) 24. The two plate members 22 extend in the extension direction of the handrail 12 inside the handrail 12 and abut against both inner wall surfaces 12e of the handrail 12 under the spring force of the spring members 24. The plurality of spring members 24 are arranged between the two plate members 22 at intervals in their length directions.

[0017] The pair of plate members 22 of the wind noise reduction device 14 are each composed of a flat plate made of metal such as aluminum or steel, a flat plate made of wood, a flat plate made of synthetic resin, or a flat plate made of rubber. The plate member 22 has a length dimension L2 (L2 < L1) that is shorter than the length dimension L1 of the handrail 12 (see FIG. 3). Further, the handrail 12 has a width dimension that is smaller than the width dimension of the inner wall surface 12e of the handrail 12 (see FIG. 3). Also, considering its elastic deformability (curvability), the plate member 22 preferably has a thickness dimension in the range of 0.5 to 3.0 mm. Instead of the illustrated example in which the contact targets of the two plate members 22 are the pair of inner wall surfaces 12e, it can be the other pair of inner wall surfaces 12d. [[ID=?]]

[0018] [[ID=?]] It seems there are some incorrect tag references in your original text (IDs 10 and 11 which are not used in the correct way in the source text). I've translated as accurately as possible based on the provided content.The length dimension L2 of the plate member 22 is such that when the vertical lattice handrail 10 is subjected to wind, and the wind blows through the gaps between the balusters 12 of the vertical lattice handrail 10, causing vibrations of one or more of the primary vibration mode (Figure 4(b)), secondary vibration mode (Figure 4(c)), and tertiary vibration mode (Figure 4(d)), the balusters 12 have a length dimension that allows them to contact the inner wall surface 12e of the balusters 12 at the peaks of the amplitude, which are the peaks or troughs of the vibrations (the location of one peak P1 in the primary vibration mode, the locations of two peaks P2 and P3 in the secondary vibration mode, and the locations of three peaks P4 to P6 in the tertiary vibration mode). Here, the definition of a vertical lattice handrail 10 being subjected to wind and causing vibrations of one or more of the primary, secondary, and tertiary vibration modes in each balusters 12 is based on the understanding that the wind speed (wind velocity) that normally acts on the vertical lattice handrail 10 is in the range of 5 to 15 m / s, and that the vibrations of each balusters 12 within this wind speed range are vibrations of one or more of the primary to tertiary vibration modes.

[0019] In the illustrated example, the location P1 of one amplitude peak in the vibration of the first vibration mode is at a distance equivalent to 6 / 12 = 1 / 2 of the length dimension L2 of the balusters 12 (see Figure 4(b)) from the upper end 12a and lower end 12b of the balusters 12, i.e., at the center in the longitudinal direction of the balusters 12. The locations P2 and P3 of the two amplitude peaks in the vibration of the second vibration mode are at distances equivalent to 3 / 12 = 1 / 4 of the length dimension L2 of the balusters 12 (see Figure 4(c)) from the upper end 12a and lower end 12b of the balusters 12, respectively. Furthermore, two of the three peaks in amplitude during the third vibration mode, P4 and P6, are located at distances corresponding to 2 / 12 = 1 / 6 of the length L2 of the balusters 12 (see Figure 4(d)) from the upper end 12a and lower end 12b of the balusters 12, respectively. The remaining peak, P5, is located at a distance corresponding to 6 / 12 = 1 / 2 of the length L2 of the balusters 12, i.e., at the center of the balusters 12 in the longitudinal direction.

[0020] The three spring members 24 of the wind noise reduction device 14, in the illustrated example, consist of two spring members 24 located near the ends of both plate members 22, and one spring member 24. This one spring member 24 is located midway between the positions of the two spring members 24 located near the ends of both plate members 22, i.e., in the center along the length of the balusters 12 (see Figure 4(b)). The illustrated spring member 24 is made of a compression coil spring and is fixed to both plate members 22 at both ends 24a. The two plate members 22 are thus connected to each other via the three spring members 24.

[0021] The wind noise reduction device 14 compresses its pair of plate members 22 toward the other, compressing a plurality of spring members 24 between the two plate members 22, and can be inserted into the interior of the balusters 12 used in the manufacture of the vertical lattice handrail 10, from one end 12a, 12b toward the other. This allows the wind noise reduction device 14 to be easily placed inside the balusters 12.

[0022] Both plate members 22, inside the balusters 12, receive a pressing force which is the elastic restoring force of the compressed spring members 24, and come into contact with the inner wall surfaces 12e of the balusters 12, respectively, so that the contact surfaces 22a of each are in close contact with the inner wall surfaces 12e of the balusters 12.

[0023] Here, the contact surface 22a of the plate member 22 is the surface of the plate member 22 that contacts the inner wall surface 12e of the balusters 12. Furthermore, in the wind noise reduction device 14, the state in which the contact surface 22a of the plate member 22 is in close contact with the inner wall surface 12e of the balusters 12 means that the entire surface of the contact surface 22a is in contact with the inner wall surface 12e.

[0024] In the wind noise reduction device 14, the spring constants, lengths, and number of spring members 24 are set such that multiple spring members 24 keep the respective contact surfaces 22a of both plate members 22 in close contact with the inner wall surface 12e, and exert a pressing force that allows the plate members 22 and the inner wall surface 12e to move relative to each other when the balusters 12 are deformed.

[0025] As a result, in the wind noise reduction device 14, even when the balusters 12 undergo elastic deformation due to the vertical lattice handrail 10 being exposed to wind, as will be described later, the contact surface 22a remains in close contact with the inner wall surface 12e. Furthermore, when the balusters 12 undergo elastic deformation, a small amount of slippage occurs between the contact surface 22a and the inner wall surface 12e, generating friction.

[0026] Next, the operation of the wind noise reduction device 14 will be explained.

[0027] When a vertical lattice handrail 10, which is equipped with multiple balusters 12 to which wind noise reduction devices 14 are attached, is subjected to wind, vibrations of one or more of the primary, secondary, and tertiary vibration modes occur in the balusters 12. When the balusters 12 undergo elastic deformation (curving deformation) corresponding to the vibrations caused by these vibrations, the two plate members 22, whose contact surfaces 22a are in close contact with both inner wall surfaces 12e of the balusters 12, undergo elastic deformation along the curved inner wall surfaces 12e of the balusters 12, receiving an external force from the balusters 12 due to its elastic deformation. At this time, the two plate members 22 vibrate with their respective spring members 24 as fulcrums, and while maintaining the state in which their contact surfaces 22a are in close contact with both inner wall surfaces 12e of the balusters 12, they slide slightly along both inner wall surfaces 12e of the balusters 12. As a result, friction occurs between the inner wall surfaces 12e of the balusters 12 and the contact surfaces 22a of the two plate members 22.

[0028] This friction acts as a force that attempts to stop vibrations as frictional damping (energy loss due to friction when considering energy balance), thereby increasing the damping capacity of the balusters 12. Consequently, friction occurs between the inner wall surface 12e of the balusters 12 and the contact surface 22a of the two plate members 22, reducing the vibration of the balusters 12 and the associated wind noise.

[0029] In the illustrated example, the length dimension L2 of the plate member 22 is set to 10 / 12 of the length dimension L1 of each balusters (Figure 4(a)), and the upper and lower ends 12a and 12b of the plate member 22 are positioned at a distance of 1 / 12 of the length dimension L1 of the balusters 12 from the upper and lower ends 12a and 12b of the balusters 12, respectively. According to the illustrated example, even if the wind noise reduction device 14 slides down inside the balusters 12 to the lower end 12b of the balusters 12 due to its own weight when the balusters 12 vibrate, both plate members 22 are maintained in a state where they can contact the inner wall surface 12e of the balusters 12 at the location P1 of one peak in the primary vibration mode, at the locations P2 and P3 of two peaks in the secondary vibration mode, and at the locations P4, P5 and P6 of three peaks in the tertiary vibration mode.

[0030] Next, the principle by which the wind noise reduction device 14 reduces vibrations of the handrail 12 will be explained.

[0031] If we consider the damping constant h of the balusters 12 to be the sum of the damping constant h1 inherent in the balusters 12 itself and the damping constant h2 due to frictional damping caused by sliding between the inner wall surface 12e of the balusters 12 and the contact surface 22a of the plate member 22, then the following equation (1) holds true.

[0032] h = h1 + h2 …(1) Here, by rearranging the equation for damping due to friction in "Damping Mechanism for a Two-Piece Laminated Plate Structure" (Masami Mashiko, et al., Transactions of the Japan Society of Mechanical Engineers (Part III), 1973, Vol. 39, No. 317, pp. 382-392), the damping constant h2 can be expressed by the following equation (2).

[0033] h2 = 4μypα / k …(2) Here, μ is the coefficient of dynamic friction, y is half the thickness of the two joined plates (balusters 12 and plate members 22) / initial displacement, p is the contact pressure between the two plate members (between the inner wall surface 12e of the balusters 12 and the contact surface 22a of the plate members 22), α is the slip ratio indicating the sliding characteristics between the two plate members, and k is the bending stiffness of the two joined plates.

[0034] Furthermore, according to the above paper, the slip ratio α can be expressed by the following equation (3).

[0035]

number

[0036] Here, A, a, and ε are constants determined by the surface state of the joint between the two plates.

[0037] Equation (3) above means that the larger the slip ratio α, the higher the damping capacity for vibrations due to friction.

[0038] In other words, if the balusters 12 to which the wind noise reduction device 14 is attached exhibit the same trend as in equation (3), then it can be determined that the reduction in vibration of the balusters 12 is due to frictional damping.

[0039] To verify this, the damping constant h in the balusters 12 to which the wind noise reduction device 14 was attached was determined from a hammering test, and the slip ratio α was calculated.

[0040] In this hammering test, two types of handrails 12 were used, both consisting of aluminum pipe members with a length of 1000 mm: one with a rectangular cross-sectional shape of 20 mm wide x 30 mm high, and another with a rectangular cross-sectional shape of 20 mm wide x 40 mm high.

[0041] Furthermore, the plate member 22 of the wind noise reduction device 14 was a steel flat plate with a thickness of 0.5 mm, a length of 950 mm, and a width of 15 mm. In addition, the spring member 24 was a compression coil spring with a spring constant of 0.5 N / mm.

[0042] Hammering tests were conducted on each of the two types of handrail posts 12 with different cross-sectional shapes described above, with each of several wind noise reduction devices 14 having a different number of spring members 24 attached.

[0043] In this hammering test, as shown in Figure 5, the contact pressure p between the inner wall surface 12e of the baluster 12 and the contact surface 22a of the plate member 22 was treated as a uniformly distributed load by averaging the sum of the pressing forces f exerted by each spring member 24 on the plate member 22 over the area of ​​the contact surface 22a of the plate member 22. Here, the pressing force f by the spring member 24 is determined from the spring stiffness and the amount of spring deformation. In the baluster 12 subjected to the hammering test, the contact pressure p increased as the number of spring members 24 of the attached wind noise reduction device 14 increased, and the range of the contact pressure p was approximately 0.0003 N / mm 2 ~0.0026 N / mm 2 That was the case.

[0044] In this hammering test, based on the finding that the vibration of the balusters 12 within the wind speed range of 5 to 15 m / s that normally acts on the vertical lattice handrail 10 is one or more of the vibration modes from the 1st to 3rd vibration modes, the vibrations of the 1st, 2nd, and 3rd vibration modes were evaluated.

[0045] The results of the hammering test are shown in Figures 6 and 7. Figure 6 is a graph showing the relationship between the contact pressure p and the damping constant at a baluster 12 measuring 20 mm wide x 30 mm high. Figure 7 is a graph showing the relationship between the contact pressure p and the damping constant h at a baluster 12 measuring 20 mm wide x 40 mm high. Here, the damping constant h can be estimated from the excitation force and acceleration applied to the baluster 12 in the hammering test.

[0046] Figures 6 and 7 show that the damping constant h tends to decrease as the contact pressure p increases.

[0047] Based on the results shown in Figures 6 and 7, the slip ratio α obtained using the relationships in equations (1) and (2) above is shown in Figures 8 to 10. Figure 8 is a graph showing the relationship between the contact pressure p and the slip ratio α for the first vibration mode vibration of a baluster 12 measuring 20 mm wide x 30 mm high and a baluster 12 measuring 20 mm wide x 40 mm high. Figure 9 is a graph showing the relationship between the contact pressure p and the slip ratio α for the second vibration mode vibration of a baluster 12 measuring 20 mm wide x 30 mm high and a baluster 12 measuring 20 mm wide x 40 mm high. Figure 10 is a graph showing the relationship between the contact pressure p and the slip ratio α for the third vibration mode vibration of a baluster 12 measuring 20 mm wide x 30 mm high and a baluster 12 measuring 20 mm wide x 40 mm high.

[0048] As shown in Figures 8 to 10, the trend was similar to that of equation (3) regardless of the cross-sectional shape of the balusters 12. That is, the contact pressure p and the sliding ratio α have the relationship schematically shown in Figure 11. From this, it can be concluded that the reduction in vibration of the balusters 12 is due to frictional damping between the inner wall surface 12e of the balusters 12 and the contact surface 22a of the plate member 22.

[0049] Here, the curve showing the relationship between contact pressure p and slip ratio α, as shown in Figure 11, varies depending on conditions such as the material of the balusters 12 and the plate member 22, the contact area, and the vibration mode. Furthermore, the slip ratio α eventually becomes 0 as the contact pressure p increases. In other words, if the contact pressure p is too large, no slip occurs between the inner wall surface 12e of the balusters 12 and the contact surface 22a of the plate member 22.

[0050] Furthermore, as shown in Figure 11, in regions where the contact pressure p is too small, although a value for the slip ratio α exists in theory, it is not possible to maintain close contact between the inner wall surface 12e of the baluster 12 and the contact surface 22a of the plate member 22. If the inner wall surface 12e and the contact surface 22a cannot maintain close contact, the effect of reducing the vibration of the baluster 12 through frictional damping between the inner wall surface 12e and the contact surface 22a cannot be sufficiently obtained.

[0051] In contrast, in the wind noise reduction device 14, as described above, multiple spring members 24 keep the contact surfaces 22a of both plate members 22 in constant contact with the inner wall surface 12e, and when the handrail 12 deforms, they exert a pressing force that allows the plate members 22 and the inner wall surface 12e to move relative to each other (slip occurs between the inner wall surface 12e and the contact surface 22a).

[0052] Next, we will describe the wind tunnel experiments conducted using the results of the hammering tests described above, specifically focusing on cases where the damping constant h was relatively high and relatively low.

[0053] In this wind tunnel experiment, the four spring members 24 of the wind noise reduction device 14 produced a p = 0.000421 N / mm 2 In the case where the damping constant h is relatively high, and there are 14 spring members 24, p = 0.001474 N / mm 2 The study included the case where the damping constant h was relatively low. For comparison, the study also included the case where the balusters 12 without the wind noise reduction device 14 (balusters 12 without countermeasures).

[0054] In this wind tunnel experiment, we used vertical lattice handrails 10 with 20 balusters 12 measuring 20 mm wide x 30 mm high, vertical lattice handrails 10 with 20 balusters 12 measuring 20 mm wide x 40 mm high, vertical lattice handrails 10 with 10 balusters 12 measuring 20 mm wide x 30 mm high, and vertical lattice handrails 10 with 10 balusters 12 measuring 20 mm wide x 40 mm high. The vertical lattice handrails 10 with 10 balusters 12 have half the spacing of the balusters 12 compared to the vertical lattice handrails 10 with 20 balusters 12.

[0055] Wind tunnel experiments were conducted for each of the vertical lattice handrails 10 described above, in the following cases: when a wind noise reduction device 14 with four spring members 24 is attached to the handrail 12; when a wind noise reduction device 14 with fourteen spring members 24 is attached to the handrail 12; and when a handrail 12 without any countermeasures is used.

[0056] In this wind tunnel experiment, a wind of 3-20 m / s was blown onto the vertical grid handrail 10 from the front to the back. The A-weighted sound pressure level and the X-direction (lateral) vibration acceleration level were then measured.

[0057] The results of the wind tunnel experiment are shown in Figures 12 to 19. Figure 12 is a graph showing the relationship between the contact pressure p and the A-weighted sound pressure level in a vertical lattice handrail 10 with 20 balusters 12 measuring 20 mm wide x 30 mm high. Figure 13 is a graph showing the relationship between the contact pressure p and the vibration acceleration level in the X direction in a vertical lattice handrail 10 with 20 balusters 12 measuring 20 mm wide x 30 mm high.

[0058] Figure 14 is a graph showing the relationship between the contact pressure p and the A-weighted sound pressure level in a vertical lattice handrail 10 with 20 balusters 12 measuring 20 mm horizontally x 40 mm vertically. Figure 15 is a graph showing the relationship between the contact pressure p and the vibration acceleration level in the X direction in a vertical lattice handrail 10 with 20 balusters 12 measuring 20 mm horizontally x 40 mm vertically.

[0059] Figure 16 is a graph showing the relationship between the contact pressure p and the A-weighted sound pressure level in a vertical lattice handrail 10 with 10 balusters 12 measuring 20 mm horizontally and 30 mm vertically. Figure 17 is a graph showing the relationship between the contact pressure p and the vibration acceleration level in the X direction in a vertical lattice handrail 10 with 10 balusters 12 measuring 20 mm horizontally and 30 mm vertically.

[0060] Figure 18 is a graph showing the relationship between the contact pressure p and the A-weighted sound pressure level in a vertical lattice handrail 10 with 10 balusters 12 measuring 20 mm horizontally and 40 mm vertically. Figure 19 is a graph showing the relationship between the contact pressure p and the vibration acceleration level in the X direction in a vertical lattice handrail 10 with 10 balusters 12 measuring 20 mm horizontally and 40 mm vertically.

[0061] As shown in Figures 12 to 19, in both the case with 4 spring members 24 and the case with 14 spring members 24, the A-weighted sound pressure level and the X-direction vibration acceleration level were lower compared to the case without countermeasures, confirming the effect of reducing wind noise. Furthermore, in both the case with 4 spring members 24 and the case with 14 spring members 24, no wind noise was audibly detected.

[0062] In this case, when there were 14 spring members 24, the damping constant h was relatively low in the hammering test, but in the wind tunnel experiment, the A-weighted sound pressure level and the vibration acceleration level in the X direction were kept low, similar to the case with 4 spring members 24. This is thought to be because the force that vibrates the balusters 12 is greater in the wind tunnel experiment than in the hammering test, causing the balusters 12 to vibrate more, and the friction damping between the inner wall surface 12e of the balusters 12 and the contact surface 22a of the plate member 22 reduced the vibration of the balusters 12 and the associated wind noise.

[0063] As described above, the wind noise reduction device 14 comprises a pair of plate members 22 and a plurality of spring members 24 fixed to both plate members 22. The plurality of spring members 24 ensure that the respective contact surfaces 22a of both plate members 22 are always in close contact with the inner wall surface 12e (the entire surface of the contact surface 22a is always in contact with the inner wall surface 12e), and exert a pressing force that allows the plate members 22 and the inner wall surface 12e to move relative to each other when the balusters 12 are deformed.

[0064] As a result, vibration occurs in the balusters 12, and when the balusters 12 undergoes elastic deformation corresponding to this vibration, the two plate members 22 undergo elastic deformation along the inner wall surface 12e of the balusters 12. At this time, the two plate members 22 slide slightly along the inner wall surface 12e of the balusters 12 while maintaining a state in which the contact surfaces 22a are in close contact with the inner wall surface 12e of the balusters 12. As a result, friction occurs between the inner wall surface 12e of the balusters 12 and the contact surfaces 22a of the two plate members 22, and the vibration of the balusters 12 and the associated wind noise are reduced by friction damping.

[0065] Here, since the wind noise reduction device 14 is not fixed to the balusters 12 by fasteners or welding, the plate member 22 can slide on the inner wall surface 12e of the balusters 12 as described above. For this reason, as described above, the vibration of the balusters 12 and the wind noise associated with it can be reduced by friction damping between the inner wall surface 12e of the balusters 12 and the contact surface 22a of the plate member 22.

[0066] Furthermore, the wind noise reduction device 14 can be inserted into the handrail 12 by compressing the multiple spring members 24 between the two plate members 22, and does not need to be fixed to the handrail 12 by fasteners or welding, so it can be easily installed on the handrail 12.

[0067] Therefore, the wind noise reduction device 14 is easy to install on the balusters 12 and can reduce wind noise from the vertical lattice handrail 10.

[0068] In the embodiment described above, the wind noise reduction device 14 is provided with a plurality of spring members 24, but it is not limited to spring members 24; other elastic materials such as sponges may also be used.

[0069] Furthermore, in the embodiment described above, the plate member 22 has a length that allows it to contact the inner wall surface 12e of the baluster 12 at the location of the amplitude peak of the vibration that occurs when one or more vibration modes from the primary, secondary, and tertiary vibration modes occur in the baluster 12. However, it may have a length other than this.

[0070] The present invention is not limited to the embodiments described above, and in the implementation stage, the components can be modified and implemented without departing from the spirit of the invention. Furthermore, various inventions can be formed by appropriately combining the multiple components disclosed in the above embodiments. For example, some components may be deleted from all the components shown in the embodiments. [Explanation of symbols]

[0071] 10 Vertical lattice handrail 12 Baluster 12e, 12f Interior wall surface 14. Wind noise reduction device 22 Plate members 22a Contact surface 24 Spring component P1~P6 Location of vibration peaks

Claims

1. A wind noise reduction device applicable to a grid-like structure consisting of a handrail or fence equipped with a plurality of hollow balusters having a rectangular cross-sectional shape, A pair of opposing plate members arranged inside each balusters, the pair of plate members extending in the extension direction of the balusters within the balusters, It comprises a plurality of elastic bodies arranged between the two plate members at intervals from each other in the longitudinal direction of the two plate members and fixed to the two plate members. A wind noise reduction device wherein the plurality of elastic bodies keep the entire surface of each plate member that contacts the inner wall surface of the balusters in constant contact with the inner wall surface, and exert a pressing force that allows the plate members and the inner wall surface to move relative to each other when the balusters are deformed.

2. The wind noise reduction device according to claim 1, wherein both plate members have a length dimension that allows them to contact the inner wall surface of each handrail at the point of the amplitude peak of the vibration when the grid-like structure is subjected to wind and vibration of one or more of the primary, secondary, and tertiary vibration modes occurs in each handrail.

3. The wind noise reduction device according to claim 2, wherein each plate member has a length dimension corresponding to 10 / 12 of the length dimension of each handrail post.

4. The wind noise reduction device according to claim 3, wherein both plate members are positioned at an interval corresponding to 1 / 12 of the length dimension of the handrail from one end and the other end of the handrail, respectively.

5. The wind noise reduction device according to any one of claims 1 to 4, wherein the plurality of elastic bodies consist of two elastic bodies located near both ends of the two plate members, and one elastic body located midway between the positions of the two elastic bodies.

6. The wind noise reduction device according to any one of claims 1 to 4, wherein the elastic body is a compression coil spring.

7. A baluster used in the manufacture of a lattice structure consisting of a handrail or fence, A pipe member having a rectangular cross-sectional shape, A baluster comprising a wind noise reduction device according to any one of claims 1 to 4, disposed inside the pipe member.

8. A grid-like structure consisting of a handrail or fence having multiple balusters, A grid-like structure in which each baluster is made from a baluster as described in claim 7.

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