Wind noise reduction device for lattice structures, balusters and lattice structures

Abstract

To provide a new wind noise reduction device for reducing wind noise of a grid-like structure, a baluster to which the wind noise reduction device is attached, and a grid-like structure provided with the baluster.SOLUTION: A wind noise reduction device 14 applied to a grid-like structure 10 having a plurality of hollow balusters 12 of rectangular cross section includes a pair of plate members 22 arranged inside the baluster and facing each other and extending in the extension direction of the baluster inside the baluster, and a plurality of spring members arranged between the two plate members at intervals in the longitudinal direction thereof and fixed to the two plate members to exert a pressing force on the two plate members so as to contact the inner wall surface of the baluster. The two plate members have a length dimension that allows them to contact the inner wall surface of the baluster at the peaks of amplitude in the vibrations produced when the grid-like structure receives the wind and the balusters vibrate in one or more of the primary, secondary and tertiary vibration modes.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention is directed to reducing the volume of structure-borne sound (hereinafter referred to as wind noise) emitted by lattice structures made of handrails installed on windows, verandas, balconies, rooftops, emergency stairs, etc. of buildings, or fences installed on the boundaries of land, houses, etc., when they are hit by wind. [Background technology]

[0002] The lattice structure is equipped with a plurality of balusters that are spaced apart and extend linearly vertically, horizontally, or diagonally. The wind noise is generated by a resonance phenomenon (vortex-induced vibration) that occurs when the predominant frequency of Karman vortices generated when wind blows through the balusters of the lattice structure matches the natural frequency of the balusters, or when the predominant frequency of the Karman vortices is close to the natural frequency of the balusters.

[0003] In order to reduce the volume of wind noise in vertical lattice handrails, which are one type of lattice structure, a conventional approach has been to place a pair of metal plates partially facing each other at the bottom of a hollow balusters with a rectangular cross section. Each metal plate is fixed to the balusters with bolts, extends upward from the lower end of the balusters, and contacts the inner wall surface of the balusters. However, this approach has been deemed insufficient in terms of preventing wind noise. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-30364 Summary of the Invention [Problem to be solved by the invention]

[0005] In view of the above-described conventional circumstances, the present invention provides a new wind noise reduction device for reducing wind noise in a lattice structure, a balusters to which the wind noise reduction device is attached, and a lattice structure including the balusters. [Means for solving the problem]

[0006] This invention (first invention) relates to a wind noise reduction device that can be applied to a lattice structure consisting of a handrail or fence that includes a plurality of hollow balusters with a rectangular cross section. The wind noise reduction device comprises a pair of plate members that face each other and are arranged inside each balusters, extending in the extension direction of the balusters inside the balusters, and a plurality of spring members that are arranged between the two plate members at intervals in the length direction of the two plate members and are fixed to the two plate members, the spring members applying a pressing force to the two plate members inside each balusters so that the two plate members abut against the inner wall surfaces of the respective balusters. The two plate members are ,before The lattice structure catches the wind Each When vibration of one or more of the primary, secondary, and tertiary vibration modes occurs in the balusters, the peak of the amplitude of the vibration occurs. Each It has a length that allows it to abut against the inner wall surface of the balusters.

[0007] In the present invention, the phrase "when the lattice structure is subjected to wind and each baluster vibrates in one or more of the primary, secondary and tertiary vibration modes" is based on the knowledge that the wind speed (wind velocity) that normally acts on the lattice structure is within the range of 5 to 15 m / s, and that within this wind speed range, each baluster vibrates in one or more of the primary to tertiary vibration modes.

[0008] The present invention (second invention) relates to a balusters used in the manufacture of lattice structures consisting of handrails or fences. The balusters include a tubular member having a rectangular cross section and the wind noise reduction device disposed inside the tubular member.

[0009] The present invention (third invention) relates to a lattice structure comprising a handrail or fence having a plurality of balusters, wherein the balusters of the lattice structure are the balusters according to the second invention.

[0010] The wind noise reduction device according to the present invention can be placed inside a balustrade by pressing the pair of plate members toward each other to compress the multiple spring members between the two plate members, and then inserting the plate members from one end of the balustrade of an unmanufactured lattice structure into the inside of the balustrade from the other end. Inside the balustrade, both plate members receive a pressing force, which is the elastic return force of the multiple compressed spring members, and come into contact with the inner wall surface of the baluster, bringing them into close contact with the inner wall surface of the baluster.

[0011] According to the present invention, when a lattice-like structure including a plurality of balusters to which the wind noise reduction device is attached is subjected to wind, each baluster experiences vibrations in one or more of the primary, secondary, and tertiary vibration modes. Each baluster elastically deforms in response to the vibrations. At this time, the two plate members within each baluster are in contact with the inner wall surface of the baluster at the peak of the amplitude of the vibrations generated in the baluster. Therefore, they receive external forces from the balusters due to their elastic deformation and elastically deform along the inner wall surface of the baluster. Furthermore, both plate members vibrate around the spring members as fulcrums, sliding slightly on the inner wall surface of the baluster. As a result, friction occurs between the inner wall surface of the baluster and both plate members. This friction dissipates the vibration energy of the baluster, reducing the vibration of the baluster and the associated wind noise.

[0012] The length of each plate member is preferably set to a size equivalent to 10 / 12 of the length of each balusters. Here, both plate members are arranged such that one and the other of their ends are spaced apart from the other end of the balusters by a distance equivalent to 1 / 12 of the length of the balusters. This allows both plate members to remain in contact with the inner wall surfaces of each balusters at the peak points of the vibration amplitude of the balusters, even if the wind noise reduction device slides down inside the balusters due to its own weight when the balusters vibrate, all the way to the bottom of the balusters.

[0013] The plurality of spring members preferably includes two spring members located near both ends of each plate member and one spring member located midway between the two spring members. The spring members may be, for example, compression coil springs. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 is a perspective view of a vertical lattice handrail, which is one example of a lattice structure according to the present invention. [Figure 2] FIG. 2 is a schematic vertical cross-sectional view showing a wind noise reduction device and a balustrade to which the wind noise reduction device is attached. [Figure 3] FIG. 3 is a plan view of the wind noise reduction device and balusters shown in FIG. 2. [Figure 4] (a) is a schematic vertical cross-sectional view of the balusters and the wind noise reduction device inside them when not vibrating. (b) is a schematic vertical cross-sectional view of the balusters and the wind noise reduction device inside them when vibrating in the first vibration mode. (c) is a schematic vertical cross-sectional view of the balusters and the wind noise reduction device inside them when vibrating in the second vibration mode. (d) is a schematic vertical cross-sectional view of the balusters and the wind noise reduction device inside them when vibrating in the third vibration mode. [Figure 5] 10 is a graph showing the results of verification of wind noise reduction through a wind tunnel experiment. DETAILED DESCRIPTION OF THE INVENTION

[0015] The present invention is directed to reducing wind noise from lattice structures such as handrails (vertical lattice handrails, horizontal lattice handrails, diagonal lattice handrails, etc.) installed on building windows, verandas, balconies, rooftops, emergency stairs, etc., or fences installed on the boundaries of land, houses, etc.

[0016] 1, a vertical lattice handrail, which is an example of a lattice structure to which the present invention is applied, is generally indicated by the reference numeral 10. The vertical lattice handrail 10 comprises a plurality of balusters 12 and a wind noise reduction device 14 (FIGS. 2 and 3) attached to each balusters 12.

[0017] The illustrated vertical lattice handrail 10 includes a pair of columns 16 extending in the vertical direction (up and down direction), and two upper and lower chord members 18 fixed to both columns 16 and extending in the horizontal direction. A plurality of handrail segments 12 are arranged at intervals between both chord members 18 and extend in the vertical direction. Each handrail segment 12, each column 16, and each chord member 18 are made of, for example, aluminum extrusion profiles.

[0018] As shown in FIGS. 2 and 3, the handrail segment 12 is made of a pipe member having a rectangular cross-sectional shape. The handrail segment 12 has upper and lower ends 12a and 12b facing each other, and is fixed to the upper and lower chord members 18 at both the upper and lower ends 12a and 12b. Further, the handrail segment 12 has two pairs of outer wall surfaces (outer sides) 12c and 12d facing each other, and two pairs of inner wall surfaces (inner sides) 12e and 12f facing each other (see FIGS. 2 and 3). One pair of outer wall surfaces 12c of the handrail segment 12 faces an adjacent handrail segment 12 or 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.

[0019] The wind noise reduction device 14 includes a pair of plate members 22 facing each other and arranged inside the handrail segment 12, and a plurality (three in the illustrated example) of spring members 24. Both plate members 22 extend in the extension direction of the handrail segment 12 inside the handrail segment 12 and abut against both inner wall surfaces 12e of the handrail segment 12 under the spring force of the spring members 24. Further, the plurality of spring members 24 are arranged at intervals in their length directions between both plate members 22.

[0020] The pair of plate members 22 of the wind noise reduction device 14 are each made of, for example, a flat plate made of metal such as aluminum or steel, wood, synthetic resin, or rubber. The plate member 22 has a length dimension L2 (L2 < L1) shorter than the length dimension L1 of the handrail segment 12 (see FIG. 3). Further, the handrail segment 12 has a width dimension smaller than the width dimension of the inner wall surface 12e of the handrail segment 12 (see FIG. 3). Further, 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 both plate members 22 are the pair of inner wall surfaces 12e, it can be the other pair of inner wall surfaces 12d.

[0021] 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 between the balusters 12 of the vertical lattice handrail 10, causing the balusters 12 to vibrate in 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 plate member 22 can abut against the inner wall surface 12e of the handrail 12 at the amplitude peak points, which are the tops of the mountains or the bottoms of the valleys of the vibrations that have occurred (the location of the one peak P1 in the primary vibration mode, the locations of the two peaks P2 and P3 in the secondary vibration mode, and the locations of the three peaks P4 to P6 in the tertiary vibration mode). Here, the reason why it is defined as when the lattice structure 10 is subjected to wind and each handrail 12 vibrates in one or more of the primary, secondary, and tertiary vibration modes is based on the knowledge that the wind speed (wind velocity) that normally acts on the lattice structure 10 is within the range of 5 to 15 m / s, and that within this wind speed range, the vibration of each handrail 12 is in one or more of the primary to tertiary vibration modes.

[0022] In the illustrated example, point P1 of one peak in the amplitude of the vibration in the primary vibration mode is located at a distance equivalent to 6 / 12 = 1 / 2 of the length dimension L2 of the baluster 12 (see FIG. 4(b)) from the upper end 12a and lower end 12b of the baluster 12, i.e., at the center in the longitudinal direction of the baluster 12. Furthermore, points P2 and P3 of two peaks in the amplitude of the vibration in the secondary vibration mode are located at a distance equivalent to 3 / 12 = 1 / 4 of the length dimension L2 of the baluster 12 (see FIG. 4(c)) from the upper end 12a and lower end 12b of the baluster 12, respectively. Furthermore, of the three peaks in the amplitude of the vibration of the third vibration mode, two peaks P4 and P6 are located at a distance equivalent to 2 / 12 = 1 / 6 of the length dimension L2 of the balusters 12 (see Figure 4(d)) from the upper end 12a and lower end 12b of the balusters 12, respectively, and the remaining peak P5 is located at a distance equivalent to 6 / 12 = 1 / 2 of the length dimension L2 of the balusters 12, i.e., at the center position in the longitudinal direction of the balusters 12.

[0023] In the illustrated example, the three spring members 24 of the wind noise reduction device 14 consist of two spring members 24 located near both ends of both plate members 22, and one spring member 24. The one spring member 24 is located midway between the positions of the two spring members 24, i.e., at the center in the longitudinal direction of the balusters 12 (see FIG. 4(b)). The illustrated spring member 24 consists of a compression coil spring, and is fixed to both plate members 22 at both end portions 24a. Both plate members 22 are thereby connected to each other via the three spring members 24.

[0024] The wind noise reduction device 14 can be inserted into the interior of the balusters 12 used in the manufacture of the vertical lattice handrail 10 from one of the upper and lower ends 12a, 12b of the balusters 12 toward the other by pressing the pair of plate members 22 toward each other and compressing the multiple spring members 24 between the plate members 22, thereby allowing it to be placed inside the balusters 12. Inside the balusters 12, both plate members 22 receive a pressing force, which is the elastic return force of the multiple compressed spring members 24, and come into contact with both inner wall surfaces 12e of the balusters 12, respectively, and are placed in close contact with both inner wall surfaces 12e of the balusters 12.

[0025] When a vertical lattice handrail 10, which includes multiple balusters 12 to which wind noise reduction devices 14 are attached, is hit by wind, the balusters 12 vibrate in one or more of the primary, secondary, and tertiary vibration modes. When the balusters 12 undergo elastic deformation (curved deformation) corresponding to this vibration, the plate members 22, which are in close contact with the inner wall surfaces 12e of the balusters 12, receive an external force from the balusters 12 due to their elastic deformation and elastically deform along the curved inner wall surfaces 12e of the balusters 12. At this time, the plate members 22 vibrate with each spring member 24 as a fulcrum and also slide slightly on the 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 plate members 22. This friction dissipates the vibration energy of the balusters 12, reducing the vibration of the balusters 12 and the associated wind noise.

[0026] In the example shown, the length L2 of the plate members 22 is set to 10 / 12 of the length L1 of each balusters ( FIG. 4(a)), and the upper and lower ends 12a, 12b of the plate members 22 are disposed at intervals of 1 / 12 of the length L1 of the balusters 12 from the upper and lower ends 12a, 12b of the balusters 12, respectively. According to the example shown, even if the wind noise reduction device 14 slides down inside the balusters 12 to the lower ends 12b of the balusters due to its own weight when the balusters 12 vibrate, both plate members 22 will remain in a state where they can abut against the inner wall surfaces 12e of the balusters 12 at the one peak P1 of the primary vibration mode, at the two peaks P2 and P3 of the secondary vibration mode, and at the three peaks P4, P5, and P6 of the tertiary vibration mode.

[0027] Figure 5 shows a graph of the results of wind tunnel testing of three vertical lattice handrails conducted to verify the effectiveness of wind noise reduction by the wind noise reduction device 14. Each vertical lattice handrail has 22 balusters 12 with a rectangular cross section, and these balusters 12 are arranged at intervals of 25 mm. The wind tunnel testing was conducted by blowing wind at a speed of 5 to 15 m / s, which is equivalent to everyday wind, from the front side to the back side of each vertical lattice handrail.

[0028] In the drawing, one vertical lattice handrail to which a wind noise reduction device 14 is not attached is labeled "no measures." Furthermore, two vertical lattice handrails to which a wind noise reduction device 14 is attached are labeled "measures applied (1 mm)" and "measures applied (2 mm)," respectively. The 1 mm and 2 mm in parentheses indicate the thicknesses of the plate members 22 of the wind noise reduction device 14, respectively.

[0029] The balusters 12 of the vertical lattice handrail are made of extruded aluminum. The widths of the outer wall surfaces 12c and 12d of the vertical lattice handrail are 30 mm and 15 mm, respectively, the length L1 is 1055 mm, and the thickness is 0.85 mm.

[0030] Each plate member 22 of the wind noise reduction device 14 is made of steel plate and has a width dimension of 15 mm and a length dimension L2 of 1000 mm. Each spring member 24 is made of piano wire (SWP-A) and has an outer diameter of 12 mm, a wire diameter of 1.2 mm, and a spring constant of 5.05 N / mm. The wind noise reduction device 14 is arranged in a similar manner to that shown in Figure 4(a).

[0031] The graph in Figure 5 shows that the A-weighted sound pressure levels for "with measures (1 mm)" and "with measures (2 mm)" are equal to or higher than the A-weighted sound pressure level for "without measures" at wind speeds of 6 m / s and 8 m / s, but are lower than the A-weighted sound pressure level for "without measures" at other wind speeds.

[0032] Therefore, we investigated the cause of this and found that at wind speeds of 6 m / s and 8 m / s, a whistling sound different from the structure-borne sound was generated by the wind passing between the left support post 16 of the vertical lattice handrail 10 and the balusters 12 adjacent to said support post as seen in Figure 1, and that this whistling sound was causing the A-weighted sound pressure level to increase.

[0033] From the above, it was confirmed that the A-weighted sound pressure levels for "with countermeasures (1 mm)" and "with countermeasures (2 mm)" were lower than the A-weighted sound pressure level for "without countermeasures" at all wind speeds between 5 and 15 m / s, and that the wind noise reduction effect was apparent. [Explanation of symbols]

[0034] 10 Vertical lattice handrail 12 Baluster 14 Wind noise reduction device 22 Plate members 24 Spring member P1~P6 Vibration peak points

Claims

1. A wind noise reduction device applied to a lattice structure consisting of a handrail or fence having a plurality of hollow balusters with a rectangular cross section, a pair of opposing plate members disposed inside each balusters, the pair of plate members extending in the extension direction of the balusters inside the balusters; a plurality of spring members disposed between both plate members at intervals in the length direction of both plate members and fixed to both plate members, the plurality of spring members exerting a pressing force on both plate members inside each balusters so that both plate members abut against the inner wall surfaces of each balusters.

2. 2. The wind noise reduction device according to claim 1, wherein the plurality of spring members comprise two spring members located near both ends of each of the plate members, and one spring member located midway between the positions of the two spring members.

3. 3. The wind noise reduction device according to claim 1, wherein the spring member is a compression coil spring.

4. A balusters used in the manufacture of a lattice structure consisting of a handrail or fence, a tubular member having a rectangular cross-sectional shape; a pair of plate members facing each other and disposed inside the tubular member, the pair of plate members extending in the extension direction of the tubular member inside the tubular member; a plurality of spring members disposed between the plate members at intervals in the longitudinal direction of the plate members and fixed to the plate members, the plurality of spring members exerting a pressing force on the plate members inside the tubular member so that the plate members each come into contact with an inner wall surface of the tubular member; Both plate members have length dimensions that allow them to abut against the inner wall surface of the pipe member at the peak of the amplitude of the vibration that occurs when the lattice structure is exposed to wind and the pipe member vibrates in one or more of the primary vibration mode, secondary vibration mode, and tertiary vibration mode.

5. A handrail as described in Claim 4, wherein each of the plate members has a length dimension equivalent to 10 / 12 of the length dimension of the tubular member.

6. A handrail as described in Claim 5, wherein one and the other of both ends of each plate member are respectively positioned at a distance equivalent to 1 / 12 of the length dimension of the tubular member from one and the other of both ends of the tubular member.

7. A lattice structure consisting of a handrail or fence having a plurality of balusters, A lattice structure, each of which is made of a balusters according to any one of claims 4 to 6.

Images