Wind noise reduction device, baluster, and lattice structure

Abstract

To provide a wind noise reduction device that can improve the performance of reducing wind noise in a lattice structure, a baluster to which the wind noise reduction device is attached, and a lattice structure with the balusters.SOLUTION: A wind noise reduction device 14 comprises: a pair of opposing plate members 22 disposed inside balusters 12 and extending in an extension direction of the balusters 12 inside the balusters 12; and a leaf spring 24 disposed between both plate members 22 and extending over an entire length in a length direction of both plate members 22. The leaf spring 24 causes an entire surface of a contact surface 22a of each of both plate members 22 to constantly contact an inner wall surface 12e of the baluster 12, and exerts a pressing force that allows the plate member 22 to slide against the inner wall surface 12e when the baluster 12 is deformed.SELECTED DRAWING: Figure 3

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 above-mentioned lattice structure has a plurality of balusters that are arranged at intervals and extend linearly vertically, horizontally, or diagonally. Wind noise is generated by a resonance phenomenon (vortex-induced vibration) that occurs when the predominant frequency of Karman vortices, which are 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] Patent Document 1 discloses a wind noise reduction device that reduces the volume of wind noise in a vertical lattice handrail, which is one type of lattice structure. This wind noise reduction device comprises a pair of plate members that are arranged opposite each other inside the balusters and extend in the extension direction of the balusters, and a plurality of spring members that are arranged between the two plate members at intervals in the longitudinal direction and that apply a pressing force to the two plate members so that they abut against the inner wall surfaces of the balusters.

[0004] When a balusters fitted with this wind noise reduction device elastically deforms in response to vibrations caused by wind, the two plate members abutting the inner wall surfaces of the balusters receive an external force from the balusters due to this elastic deformation, and elastically deform along the inner wall surfaces of the balusters. At this time, the two plate members vibrate with their respective spring members as fulcrums, and also slide slightly on the inner wall surfaces of the balusters. As a result, friction occurs between the two plate members and the inner wall surfaces of the balusters. This friction dissipates the vibration energy of the balusters, reducing the vibration of the balusters and the associated wind noise. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2023-64304 Summary of the Invention [Problem to be solved by the invention]

[0006] However, in the above-described wind noise reduction device, because multiple spring members are arranged at intervals in the length direction of the plate member, there is a risk that the plate member cannot be brought into contact with the inner wall surface of the balusters with uniform pressing force in the length direction. As a result, there is a risk that the above-described wind noise reduction device will not be able to sufficiently reduce wind noise by reducing vibrations due to friction between the two plate members and the inner wall surfaces of the balusters.

[0007] The present invention has been made in view of the above, and has an object to provide a wind noise reduction device that can improve the performance of reducing wind noise in a lattice structure, a balusters to which the wind noise reduction device is attached, and a lattice structure equipped with balusters. [Means for solving the problem]

[0008] In order to achieve the above object, the wind noise reduction device of the present invention is a wind noise reduction device that is applied to a lattice structure consisting of a handrail or fence with a plurality of hollow balusters, and is equipped with a pair of opposing plate members that are placed inside each balusters and extend inside the balusters in the extension direction of the balusters, and a leaf spring that is placed between both plate members and extends over the entire length of both plate members in the longitudinal direction, the leaf spring causing the entire surfaces of both plate members that come into contact with the inner wall surfaces of the balusters to always be in contact with the inner wall surfaces, and when the balusters are deformed, a pressing force that allows the plate members to slide against the inner wall surfaces.

[0009] The balusters of the present invention are balusters used in the manufacture of lattice structures consisting of handrails or fences, and include a hollow tubular member and the above-described wind noise reduction device of the present invention placed inside the tubular member.

[0010] The lattice structure of the present invention is a lattice structure consisting of a handrail or fence having a plurality of balusters, each of which is the balusters of the present invention described above. [Effects of the Invention]

[0011] According to the present invention, it is possible to provide a wind noise reduction device that can improve the performance of reducing wind noise in a lattice structure, a balusters to which the wind noise reduction device is attached, and a lattice structure equipped with balusters. [Brief explanation of the drawings]

[0012] [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] 1 is a schematic vertical cross-sectional view showing a wind noise reduction device according to a first embodiment and a balusters to which the wind noise reduction device is attached. FIG. [Figure 3] FIG. 3 is a cross-sectional view taken along line AA 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] FIG. 10 is a schematic cross-sectional view showing a wind noise reduction device according to a second embodiment and a balusters to which the wind noise reduction device is attached. [Figure 6] FIG. 10 is a schematic cross-sectional view showing a wind noise reduction device according to a third embodiment and a balusters to which the wind noise reduction device is attached. [Figure 7] FIG. 10 is a schematic cross-sectional view showing a wind noise reduction device according to a fourth embodiment and a balustrade to which the wind noise reduction device is attached. [Figure 8] FIG. 10 is a schematic cross-sectional view showing a wind noise reduction device according to a fifth embodiment and a balusters to which the wind noise reduction device is attached. [Figure 9] FIG. 10 is a schematic cross-sectional view showing a wind noise reduction device according to a sixth embodiment and a balusters to which the wind noise reduction device is attached. [Figure 10] FIG. 13 is a schematic cross-sectional view showing a wind noise reduction device according to a seventh embodiment and a balusters to which the wind noise reduction device is attached. [Figure 11] FIG. 13 is a schematic vertical cross-sectional view showing a wind noise reduction device according to an eighth embodiment and a balusters to which the wind noise reduction device is attached. [Figure 12] FIG. 12 is a cross-sectional view taken along line BB in FIG. [Figure 13] FIG. 13 is a schematic vertical cross-sectional view of a baluster and a wind noise reduction device therein during vibration in the second vibration mode in the eighth embodiment. [Figure 14] FIG. 13 is a schematic cross-sectional view showing a wind noise reduction device according to a ninth embodiment and a balusters to which the wind noise reduction device is attached. [Figure 15] FIG. 10 is a diagram showing the results of a hammering test. [Figure 16] FIG. 10 is a diagram showing the results of a wind tunnel experiment conducted on the first to third embodiments using a vertical lattice handrail with ten balusters arranged thereon. [Figure 17] FIG. 10 is a diagram showing the results of a wind tunnel experiment conducted on the first to third embodiments using a vertical lattice handrail with ten balusters arranged thereon. [Figure 18] FIG. 10 is a diagram showing the results of a wind tunnel experiment conducted on the third to fifth embodiments using a vertical lattice handrail with five balusters arranged thereon. [Figure 19] FIG. 10 is a diagram showing the results of a wind tunnel experiment conducted on the third to fifth embodiments using a vertical lattice handrail with five balusters arranged thereon. [Figure 20] FIG. 13 is a diagram showing the results of a wind tunnel experiment conducted on the eighth embodiment. [Figure 21] FIG. 13 is a diagram showing the results of a wind tunnel experiment conducted on the eighth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the same or equivalent parts or components are designated by the same or equivalent reference numerals throughout the drawings, and their description will be omitted or simplified.

[0014] [First embodiment] 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.

[0015] As shown in Figure 1, a vertical lattice handrail 10, which is an example of the above-mentioned lattice structure, includes a plurality of balusters 12. A wind noise reduction device 14 according to the first embodiment (see Figures 2 and 3) is attached to each balusters 12.

[0016] In the following explanation, the vertical direction (up-down direction) of the vertical lattice handrail 10 is the direction perpendicular to the installation surface of the vertical lattice handrail 10. The depth direction of the vertical lattice handrail 10 is perpendicular to the vertical direction and is the direction extending from the front side to the back side of the vertical lattice handrail 10. The horizontal direction (left-right direction) of the vertical lattice handrail 10 is the direction perpendicular to the vertical direction and the depth direction. The vertical direction is the direction parallel to the vertical direction, and the depth direction and horizontal direction are directions parallel to the horizontal direction.

[0017] The illustrated vertical lattice handrail 10 comprises a pair of posts 16 extending vertically and two chord members 18, one above the other, that are fixed to the posts 16 and extend horizontally. A plurality of balusters 12 extend vertically and are spaced apart between the chord members 18. Each balusters 12, each post 16, and each chord member 18 is made of extruded aluminum, for example.

[0018] As shown in Figures 2 and 3, the balusters 12 are hollow members with a rectangular cross section, i.e., tubular members. The balusters 12 have opposing upper and lower ends 12a and 12b, and are fixed to upper and lower chord members 18 at their upper and lower ends 12a and 12b. The balusters 12 also have two pairs of opposing outer wall surfaces (outer surfaces) 12c and 12d, and two pairs of opposing inner wall surfaces (inner surfaces) 12e and 12f (see Figures 2 and 3). The pair of outer wall surfaces 12c of the balusters 12 face the adjacent balusters 12 or the support posts 16. The other pair of outer wall surfaces 12d face the front and back sides of the vertical lattice handrail 10, respectively.

[0019] Screw holes 12g are formed in each of the pair of inner wall surfaces 12f. The screw holes 12g are fastening holes for screws to fix the upper end 12a of the balusters 12 to the upper chord member 18 and the lower end 12b to the lower chord member 18.

[0020] The wind noise reduction device 14 includes a pair of opposing plate members 22 arranged inside the balusters 12, and a leaf spring 24.

[0021] Both plate members 22 extend in the extension direction of the balusters 12 inside the balusters 12 and come into contact with both inner wall surfaces 12 e of the balusters 12 due to the spring force of the leaf springs 24 .

[0022] The plate member 22 has a dimension L2 (L2≦L1) that is less than the length dimension L1 of the balusters 12 (see FIG. 2). The plate member 22 also has a width that is smaller than the width of the inner wall surface 12e of the balusters 12 (see FIG. 3). The plate member 22 is made of a flat plate. Note that the screw holes 12g of the balusters 12 may be formed in the inner wall surface 12e, and both plate members 22 may abut against the pair of inner wall surfaces 12f.

[0023] The length dimension L2 of the plate member 22 is such that when the vertical lattice handrail 10 receives 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 balusters 12 at the amplitude peak locations, 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 vertical lattice handrail 10 is hit by wind and each balusters 12 vibrates in one or more of the primary, secondary, and tertiary vibration modes is because the wind speed (wind velocity) that normally acts on the vertical lattice handrail 10 is within the range of 5 to 15 m / s, and the vibration of each balusters 12 within this wind speed range is one or more of the primary to tertiary vibration modes.

[0024] In the illustrated example, point P1 of one amplitude peak in the vibration of the primary vibration mode is located at a distance equivalent to 6 / 12 = 1 / 2 of the length dimension L1 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 amplitude peaks in the vibration of the secondary vibration mode are located at a distance equivalent to 3 / 12 = 1 / 4 of the length dimension L1 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 in the third vibration mode, two peaks P4 and P6 are located at a distance equivalent to 2 / 12 = 1 / 6 of the length dimension L1 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 L1 of the balusters 12, i.e., at the center position in the longitudinal direction of the balusters 12.

[0025] The leaf spring 24 uses its spring force to bring both plate members 22 into contact with both inner wall surfaces 12e of the balusters 12. The leaf spring 24 is disposed between both plate members 22 and extends over the entire length of both plate members 22 in the longitudinal direction (vertical direction).

[0026] The leaf spring 24 has a flat plate portion 24a disposed between the two plate members 22 and parallel to the two plate members 22, a bent portion 24b curved in an arc convex toward the back side of the vertical lattice handrail 10, and a bent portion 24c curved in an arc convex toward the front side. The left end of the bent portion 24b is connected to the left plate member 22, and the right end is connected to the rear end of the flat portion 24a. The left end of the bent portion 24c is connected to the front end of the flat portion 24a, and the right end is connected to the right plate member 22. As a result, the leaf spring 24 is bent twice in the short direction of the leaf spring 24, which is perpendicular to the extension direction of the balusters 12. Note that the leaf spring 24 may have a configuration obtained by flipping the configuration shown in FIG. 3 left and right.

[0027] The leaf springs 24 are formed integrally with both plate members 22. This improves the productivity of the wind noise reduction device 14. Furthermore, when the wind noise reduction device 14 is placed inside the balusters 12, the work of inserting it into the balusters 12 can be facilitated.

[0028] Furthermore, the leaf spring 24 is connected to one plate member 22 and the other plate member 22 at positions offset from each other in the width direction (depth direction) of the plate members 22. Specifically, in the width direction of the plate members 22, the position where the left end of the bent portion 24b of the leaf spring 24 is connected to the left plate member 22 and the position where the right end of the bent portion 24c is connected to the right plate member 22 are spaced the same distance apart in opposite directions from the center position of the plate members 22 (see FIG. 3).

[0029] The pair of plate members 22 and the leaf spring 24 of the wind noise reduction device 14 are made of resin. By forming the wind noise reduction device 14 from resin, corrosion of the wind noise reduction device 14 can be suppressed even when used in a vertical lattice handrail 10 installed outdoors. In addition, the weight of the wind noise reduction device 14 can be reduced.

[0030] The resin that can be used to form the pair of plate members 22 and the plate spring 24 of the wind noise reduction device 14 includes acrylonitrile butadiene styrene (ABS), polyvinyl chloride (PVC), polyethylene (PE), polypropylene (PP), polystyrene (PS), acrylonitrile styrene (AS), polymethyl methacrylate (PMMA), polycarbonate (PC), polyethylene terephthalate (PET), polyacetal (POM), nylon 6 (PA6), nylon 66 (PA66), and the like.

[0031] The wind noise reduction device 14 is not limited to being made of resin, and may be made of a metal such as aluminum. When the wind noise reduction device 14 is made of metal, using the same type of metal as the balusters 12 can help prevent corrosion.

[0032] The wind noise reduction device 14 can be inserted into the interior of the balusters 12 from one of the upper and lower ends 12a, 12b of the balusters 12 used in the manufacture of the vertical lattice handrail 10, with the pair of plate members 22 pressed toward each other and the leaf springs 24 between the plate members 22 compressed. Here, as described above, the wind noise reduction device 14 is formed such that the plate members 22 and the leaf springs 24 are integrally formed, and therefore the work of inserting the wind noise reduction device 14 into the interior of the balusters 12 can be carried out easily.

[0033] Inside the balusters 12, both plate members 22 are subjected to a pressing force, which is the elastic restoring force of the compressed leaf springs 24, and come into contact with both inner wall surfaces 12e of the balusters 12, with the contact surfaces 22a each in close contact with both inner wall surfaces 12e of the balusters 12.

[0034] Here, the contact surface 22a of the plate member 22 is the surface of the plate member 22 that comes into contact with the inner wall surface 12e of the balusters 12. In addition, in the wind noise reduction device 14, a 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. Note that the larger the area of ​​the contact surface 22a, the greater the effect of reducing wind noise due to frictional damping, which will be described later.

[0035] In the wind noise reduction device 14, the leaf spring 24 has a spring force that exerts a pressing force on both plate members 22 such that the contact surfaces 22a of both plate members 22 are always in close contact with the inner wall surface 12e, and when the balusters 12 are deformed, the plate members 22 can slide against the inner wall surface 12e, in other words, the plate members 22 and the inner wall surface 12e can move relative to each other.

[0036] As a result, in the wind noise reduction device 14, even when the balusters 12 are elastically deformed due to wind hitting the vertical lattice handrail 10, as will be described later, the contact surfaces 22a are maintained in close contact with the inner wall surface 12e. Furthermore, when the balusters 12 are elastically deformed, a slight slippage occurs between the contact surfaces 22a and the inner wall surface 12e, generating friction.

[0037] Next, the operation of the wind noise reduction device 14 will be described.

[0038] When a vertical lattice handrail 10 equipped with multiple balusters 12 fitted with wind noise reduction devices 14 is hit by wind, the balusters 12 vibrate in one or more of the primary, secondary, and tertiary vibration modes, and the balusters 12 undergo elastic deformation (curved deformation) corresponding to the vibrations. The two plate members 22, with their contact surfaces 22a 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 two plate members 22 slide slightly on the inner wall surfaces 12e of the balusters 12, while maintaining their contact surfaces 22a in close contact with 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 contact surfaces 22a of the two plate members 22.

[0039] This friction acts as a force that tries to stop vibration through frictional damping (energy loss due to friction when considered in terms of energy balance), increasing the damping capacity of the balusters 12. Therefore, friction occurring between the inner wall surfaces 12e of the balusters 12 and the contact surfaces 22a of both plate members 22 reduces vibration of the balusters 12 and the associated wind noise.

[0040] Furthermore, in the wind noise reduction device 14, the leaf spring 24 extends over the entire length of the plate member 22, so the plate member 22 can be brought into contact with the inner wall surface 12e of the balusters 12 with a uniform pressing force in the length direction. This improves the ability to reduce wind noise through frictional damping.

[0041] Furthermore, because the leaf spring 24 is bent in the short direction, it is possible to reduce the spring force, which makes it easier for an appropriate amount of slippage to occur between the inner wall surface 12e of the balusters 12 and the contact surface 22a of the plate member 22, making it easier to reduce wind noise due to frictional damping.

[0042] Furthermore, in the illustrated example, 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 illustrated example, 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.

[0043] The direction in which the wind noise reduction device 14 is inserted into the balusters 12 is not limited, and as mentioned above, both plate members 22 may abut against a pair of inner wall surfaces 12f, but the performance in reducing wind noise can be further improved by closely adhering the plate members 22 to the inner wall surface in the longitudinal direction of the cross section of the balusters 12 (inner wall surface 12e in the illustrated example).

[0044] [Second embodiment] Next, a second embodiment, which is a partial modification of the first embodiment, will be described.

[0045] As shown in FIG. 5, a wind noise reduction device 14A according to the second embodiment has a configuration in which the leaf spring 24 of the wind noise reduction device 14 of the first embodiment is replaced with a leaf spring 31.

[0046] The leaf spring 31 extends over the entire length of the plate member 22 in the longitudinal direction, similar to the leaf spring 24 of the first embodiment.

[0047] The leaf spring 31 has three flat plate portions 31a to 31c arranged in parallel in the horizontal direction between the two plate members 22 and parallel to the two plate members 22, two bent portions 31d and 31e that are curved in an arc convexly toward the back side of the vertical lattice handrail 10, and two bent portions 31f and 31g that are curved in an arc convexly toward the front side.

[0048] The left end of the bent portion 31d is connected to the left plate member 22, and the right end is connected to the rear end of the flat plate portion 31a. The left end of the bent portion 31e is connected to the rear end of the flat plate portion 31b, and the right end is connected to the rear end of the flat plate portion 31c. The left end of the bent portion 31f is connected to the front end of the flat plate portion 31a, and the right end is connected to the front end of the flat plate portion 31b. The left end of the bent portion 31g is connected to the front end of the flat plate portion 31c, and the right end is connected to the right plate member 22. As a result, the leaf spring 31 is bent four times in the short direction. Note that the leaf spring 31 may have a configuration in which the configuration shown in FIG. 5 is reversed left to right.

[0049] Like the leaf spring 24 of the first embodiment, the leaf spring 31 is connected to one plate member 22 and the other plate member 22 at positions offset from each other in the width direction (depth direction) of the plate members 22. Specifically, in the width direction of the plate members 22, the position where the left end of the bent portion 31d of the leaf spring 31 is connected to the left plate member 22 and the position where the right end of the bent portion 31g is connected to the right plate member 22 are spaced the same distance apart in opposite directions from the center position of the plate members 22.

[0050] Like the leaf spring 24 of the first embodiment, the leaf spring 31 has a spring force that keeps the contact surfaces 22a of both plate members 22 in constant contact with the inner wall surface 12e of both plate members 22, and exerts a pressing force that allows the plate members 22 to slide against the inner wall surface 12e when the handrail 12 is deformed.

[0051] In the wind noise reduction device 14A described above, as in the wind noise reduction device 14 of the first embodiment, the plate member 22 can be brought into contact with the inner wall surface 12e of the balusters 12 in the longitudinal direction with a uniform pressing force, and therefore the performance of reducing wind noise through frictional damping can be improved.

[0052] Furthermore, the leaf spring 31 of the wind noise reduction device 14A has a greater number of bends than the leaf spring 24 of the first embodiment, which makes it possible to further reduce the spring force. This makes it easier for an appropriate amount of slippage to occur between the inner wall surface 12e of the balusters 12 and the contact surface 22a of the plate member 22, making it possible to further reduce wind noise through frictional damping.

[0053] [Third embodiment] Next, a third embodiment, which is a partial modification of the first embodiment, will be described.

[0054] As shown in FIG. 6, a wind noise reduction device 14B according to the third embodiment has a configuration in which the leaf spring 24 of the wind noise reduction device 14 of the first embodiment is replaced with a leaf spring 36.

[0055] The leaf spring 36 extends over the entire length of the plate member 22 in the longitudinal direction, similar to the leaf spring 24 of the first embodiment.

[0056] The leaf spring 36 has four flat plate portions 36a to 36d arranged in parallel in the horizontal direction between the two plate members 22 and parallel to the two plate members 22, three bent portions 36e to 36g that are curved in an arc convexly toward the back side of the vertical lattice handrail 10, and two bent portions 36h and 36i that are curved in an arc convexly toward the front side.

[0057] The left end of the bent portion 36e is connected to the left plate member 22 and the right end is connected to the rear end of the flat plate portion 36a. The left end of the bent portion 36f is connected to the rear end of the flat plate portion 36b and the right end is connected to the rear end of the flat plate portion 36c. The left end of the bent portion 36g is connected to the rear end of the flat plate portion 36d and the right end is connected to the right plate member 22. The left end of the bent portion 36h is connected to the front end of the flat plate portion 36a and the right end is connected to the front end of the flat plate portion 36b. The left end of the bent portion 36i is connected to the front end of the flat plate portion 36c and the right end is connected to the front end of the flat plate portion 36d. As a result, the leaf spring 36 is bent five times in its short direction. The leaf spring 36 may have a configuration in which the configuration shown in FIG. 6 is reversed in the depth direction.

[0058] Like the leaf spring 24 of the first embodiment, the leaf spring 36 has a spring force that keeps the contact surfaces 22a of both plate members 22 in constant contact with the inner wall surface 12e of both plate members 22, and exerts a pressing force that allows the plate members 22 to slide against the inner wall surface 12e when the handrail 12 is deformed.

[0059] In the wind noise reduction device 14B described above, as in the wind noise reduction device 14 of the first embodiment, the plate member 22 can be brought into contact with the inner wall surface 12e of the balusters 12 in the longitudinal direction with a uniform pressing force, and therefore the performance of reducing wind noise through frictional damping can be improved.

[0060] Furthermore, the leaf spring 36 of the wind noise reduction device 14B has a greater number of folds than the leaf spring 24 of the first embodiment and the leaf spring 31 of the second embodiment, which makes it possible to further reduce the spring force. This makes it easier for an appropriate amount of slippage to occur between the inner wall surface 12e of the balusters 12 and the contact surface 22a of the plate member 22, making it possible to further reduce wind noise through frictional damping.

[0061] [Fourth embodiment] Next, a fourth embodiment, which is a partial modification of the second embodiment, will be described.

[0062] As shown in FIG. 7, a wind noise reduction device 14C according to the fourth embodiment has a configuration in which the leaf spring 31 of the wind noise reduction device 14A according to the second embodiment is replaced with a leaf spring 41.

[0063] The plate spring 41 has a configuration in which the flat plate portion 31b of the plate spring 31 of the second embodiment is replaced with two flat plate portions 41a and 41b parallel to both plate members 22.

[0064] The front end of flat plate portion 41a is connected to the right end of bent portion 31f. The rear end of flat plate portion 41b is connected to the left end of bent portion 31e. Flat plate portions 41a and 41b abut against each other so that the right surface of the rear end of flat plate portion 41a and the left surface of the front end of flat plate portion 41b overlap each other.

[0065] The flat plate portions 41a and 41b are not fixed to each other. Therefore, the leaf spring 41 is divided into a portion formed by the flat plate portions 31a and 41a and the bent portions 31d and 31f, and a portion formed by the flat plate portions 31c and 41b and the bent portions 31e and 31g. The leaf spring 41 may have a configuration obtained by flipping the configuration shown in FIG. 7 left and right.

[0066] Like the leaf spring 24 of the first embodiment, the leaf spring 41 has a spring force that keeps the contact surfaces 22a of both plate members 22 in constant contact with the inner wall surface 12e of both plate members 22, and exerts a pressing force that allows the plate members 22 to slide against the inner wall surface 12e when the handrail 12 is deformed.

[0067] In the wind noise reduction device 14C described above, as in the wind noise reduction device 14 of the first embodiment, the plate member 22 can be brought into contact with the inner wall surface 12e of the balusters 12 in the longitudinal direction with a uniform pressing force, and therefore the performance of reducing wind noise through frictional damping can be improved.

[0068] Furthermore, similar to the leaf spring 24 of the first embodiment, the leaf spring 41 of the wind noise reduction device 14C is connected to one plate member 22 and the other plate member 22 at positions offset from each other in the width direction (depth direction) of the plate members 22, thereby preventing bias in the pressing force of the leaf spring 41 in the width direction of the plate members 22. As a result, the performance of reducing wind noise through frictional damping can be further improved.

[0069] Furthermore, like the leaf spring 31 of the second embodiment, the leaf spring 41 of the wind noise reduction device 14C has a greater number of folds than the leaf spring 24 of the first embodiment, which makes it possible to further reduce the spring force. This makes it easier for an appropriate amount of slippage to occur between the inner wall surface 12e of the balusters 12 and the contact surface 22a of the plate member 22, making it possible to further reduce wind noise through frictional damping.

[0070] [Fifth embodiment] Next, a fifth embodiment, which is a partial modification of the second embodiment described above, will be described.

[0071] As shown in FIG. 8, a wind noise reduction device 14D according to the fifth embodiment has a configuration in which the leaf spring 31 of the wind noise reduction device 14A according to the second embodiment is replaced with a leaf spring .

[0072] The leaf spring 46 is configured by separating the leaf spring 31 of the second embodiment from both plate members 22, and adding two flat plate portions 46a and 46b parallel to both plate members 22.

[0073] The rear end of the flat plate portion 46a is connected to the left end of the bent portion 31d. The left surface of the flat plate portion 46a abuts against the left plate member 22. The flat plate portion 46a is not fixed to the left plate member 22. The front end of the flat plate portion 46b is connected to the right end of the bent portion 31g. The right surface of the flat plate portion 46b abuts against the right plate member 22. The flat plate portion 46b is not fixed to the right plate member 22. The leaf spring 46 may have a configuration in which the left and right sides are reversed from the configuration shown in FIG. 8.

[0074] In the wind noise reduction device 14D, the plate member 22 and the plate spring 46 may be made of different materials. The plate member 22 of the wind noise reduction device 14D may be made of wood, glass, rubber, or the like, in addition to resin or metal.

[0075] Like the leaf spring 24 of the first embodiment, the leaf spring 46 has a spring force that keeps the contact surfaces 22a of both plate members 22 in constant contact with the inner wall surface 12e of both plate members 22, and exerts a pressing force that allows the plate members 22 to slide against the inner wall surface 12e when the handrail 12 is deformed.

[0076] In the wind noise reduction device 14D described above, as in the wind noise reduction device 14 of the first embodiment, the plate member 22 can be brought into contact with the inner wall surface 12e of the balusters 12 in the longitudinal direction with a uniform pressing force, and therefore the performance of reducing wind noise through frictional damping can be improved.

[0077] Furthermore, like the leaf spring 31 of the second embodiment, the leaf spring 46 of the wind noise reduction device 14D has a greater number of folds than the leaf spring 24 of the first embodiment, which makes it possible to further reduce the spring force. This makes it easier for an appropriate amount of slippage to occur between the inner wall surface 12e of the balusters 12 and the contact surface 22a of the plate member 22, making it possible to further reduce wind noise through frictional damping.

[0078] [Sixth embodiment] Next, a sixth embodiment, which is a partial modification of the first embodiment, will be described.

[0079] As shown in FIG. 9, a wind noise reduction device 14E according to the sixth embodiment has a configuration in which the leaf spring 24 of the wind noise reduction device 14 of the first embodiment is replaced with a leaf spring 51.

[0080] The leaf spring 51 extends over the entire length of the plate member 22 in the longitudinal direction, similar to the leaf spring 24 of the first embodiment.

[0081] The leaf spring 51 is formed of a flat plate that connects one end of one plate member 22 in the width direction to the other end of the other plate member 22 in the width direction. In the example of Fig. 9, the leaf spring 51 is formed of a flat plate that connects the rear end of the left plate member 22 to the front end of the right plate member 22. Note that the leaf spring 51 may also be formed of a flat plate that connects the rear end of the right plate member 22 to the front end of the left plate member 22.

[0082] Like the leaf spring 24 of the first embodiment, the leaf spring 51 has a spring force that keeps the contact surfaces 22a of both plate members 22 in constant contact with the inner wall surface 12e of both plate members 22, and exerts a pressing force that allows the plate members 22 to slide against the inner wall surface 12e when the handrail 12 is deformed.

[0083] In the wind noise reduction device 14E described above, as in the wind noise reduction device 14 of the first embodiment, the plate member 22 can be brought into contact with the inner wall surface 12e of the balusters 12 in the longitudinal direction with a uniform pressing force, and therefore the performance of reducing wind noise through frictional damping can be improved.

[0084] [Seventh embodiment] Next, a seventh embodiment will be described.

[0085] As shown in FIG. 10, the wind noise reduction device 14F according to the seventh embodiment has a configuration in which the pair of plate members 22 of the wind noise reduction device 14 of the first embodiment are replaced with a pair of hollow members 61 (corresponding to plate members), and the leaf spring 24 is replaced with a leaf spring 62.

[0086] The hollow member 61 is a hollow member that extends in the extension direction of the balusters 12 and has a rectangular cross-sectional shape that is elongated in the depth direction.

[0087] Both hollow members 61 are arranged side by side in the horizontal direction inside the balusters 12 and abut against both inner wall surfaces 12e of the balusters 12 due to the spring force of the leaf springs 62. Both hollow members 61 have a pair of side walls 71 facing each other in the horizontal direction (left-right direction) and a pair of side walls 72 facing each other in the depth direction. The left side wall 71 of the left hollow member 61 abuts against the left inner wall surface 12e of the balusters 12, and the right side wall 71 of the right hollow member 61 abuts against the right inner wall surface 12e of the balusters 12. The hollow members 61 have length and width dimensions similar to those of the plate member 22 of the first embodiment.

[0088] The leaf spring 62 is disposed between the two hollow members 61 and extends over the entire length (vertical direction) of the two hollow members 61. The leaf spring 62 is formed integrally with the two hollow members 61.

[0089] The leaf spring 62 has three flat plate portions 62a to 62c arranged between the hollow members 61 and parallel to the side walls 71 of the hollow members 61, and four flat connection portions 62d to 62g perpendicular to the depth direction.

[0090] The left end of connecting portion 62d is connected to the right side wall 71 of the left hollow member 61, and the right end is connected to the rear end of flat plate portion 62a. The left end of connecting portion 62e is connected to the front end of flat plate portion 62a, and the right end is connected to the front end of flat plate portion 62b. The left end of connecting portion 62f is connected to the rear end of flat plate portion 62b, and the right end is connected to the rear end of flat plate portion 62c. The left end of connecting portion 62g is connected to the front end of flat plate portion 62c, and the right end is connected to the left side wall 71 of the right hollow member 61.

[0091] As a result, leaf spring 62 is bent in the short direction between connecting portion 62d and flat plate portion 62a, between flat plate portion 62a and connecting portion 62e, between connecting portion 62e and flat plate portion 62b, between flat plate portion 62b and connecting portion 62f, between connecting portion 62f and flat plate portion 62c, and between flat plate portion 62c and connecting portion 62g. Note that leaf spring 62 may have a configuration obtained by flipping the configuration shown in FIG. 10 left and right.

[0092] The wind noise reduction device 14F is formed from resin, metal, or the like, similar to the wind noise reduction device 14 of the first embodiment.

[0093] Inside the balusters 12, both hollow members 61 are subjected to a pressing force, which is the elastic restoring force of the compressed leaf springs 62, and come into contact with both inner wall surfaces 12e of the balusters 12, with the contact surfaces 71a each in close contact with both inner wall surfaces 12e of the balusters 12.

[0094] Here, the contact surface 71a of the left hollow member 61 is the surface that comes into contact with the inner wall surface 12e of the balusters 12 on the left side wall 71. The contact surface 71a of the right hollow member 61 is the surface that comes into contact with the inner wall surface 12e of the balusters 12 on the right side wall 71. Furthermore, in the wind noise reduction device 14F, a state in which the contact surface 71a of the hollow member 61 is in close contact with the inner wall surface 12e of the balusters 12 means that the entire surface of the contact surface 71a is in contact with the inner wall surface 12e.

[0095] In the wind noise reduction device 14F, the leaf springs 62 have a spring force that keeps the contact surfaces 71a of the two hollow members 61 in constant contact with the inner wall surfaces 12e, and when the handrail 12 is deformed, exerts a pressing force that allows the side walls 71 to slide against the inner wall surfaces 12e.

[0096] As a result, in the wind noise reduction device 14F, even when the balusters 12 are elastically deformed due to wind hitting the vertical lattice handrail 10, the contact surfaces 71a remain in close contact with the inner wall surface 12e. Furthermore, when the balusters 12 are elastically deformed, slight slippage occurs between the contact surfaces 71a and the inner wall surface 12e, generating friction. Therefore, similar to the wind noise reduction device 14 of the first embodiment, frictional damping reduces the vibration of the balusters 12 and the associated wind noise.

[0097] Furthermore, in the wind noise reduction device 14F, the leaf springs 62 extend over the entire length of the hollow member 61, so the side walls 71 of the hollow member 61 can be brought into contact with the inner wall surfaces 12e of the balusters 12 in the lengthwise direction with a uniform pressing force. Therefore, similar to the wind noise reduction device 14 of the first embodiment, it is possible to improve the performance of reducing wind noise through frictional damping.

[0098] Furthermore, because the leaf spring 62 is bent in the short direction, it is possible to reduce the spring force, which makes it easier for an appropriate amount of slippage to occur between the inner wall surface 12e of the balusters 12 and the contact surface 71a of the hollow member 61, making it easier to reduce wind noise due to frictional damping.

[0099] [Eighth embodiment] Next, an eighth embodiment, which is a partial modification of the second embodiment described above, will be described.

[0100] In the eighth embodiment, as shown in FIG. 11, a plurality of (four in the illustrated example) wind noise reduction devices 14G are arranged inside the balusters 12 along the extension direction of the balusters 12.

[0101] As shown in FIG. 12, a wind noise reduction device 14G has a configuration in which the pair of plate members 22 of the wind noise reduction device 14A of the second embodiment are replaced with a pair of plate members 81.

[0102] Plate member 81 has two flat plate portions 82 and a curved plate portion 83 that is curved convexly inward (toward plate spring 31). One of flat plate portions 82 is connected to the end of curved plate portion 83 on the front side, and the other flat plate portion 82 is connected to the end of curved plate portion 83 on the back side.

[0103] Both plate members 81 are subjected to the pressing force of the compressed leaf springs 31 inside the balusters 12 and come into contact with both inner wall surfaces 12e of the balusters 12, with each contact surface 82a being in close contact with both inner wall surfaces 12e of the balusters 12. Here, the contact surfaces 82a of the plate members 81 are the surfaces of both flat plate portions 82 of the plate members 81 that come into contact with the inner wall surfaces 12e of the balusters 12.

[0104] In the wind noise reduction device 14G, the leaf spring 31 has a spring force that keeps each contact surface 82a of both plate members 81 in constant contact with the inner wall surface 12e, and exerts a pressing force that allows the plate members 81 to slide against the inner wall surface 12e when the handrail 12 is deformed.

[0105] The length dimension L3 of the plate member 81 (the length dimension of the wind noise reduction device 14G) and the number of wind noise reduction devices 14G arranged inside the balusters 12 are set, for example, according to the predominant vibration mode within a predetermined wind speed range of the balusters 12. The predetermined wind speed range is, for example, the range of wind speeds that commonly act on the vertical lattice handrail 10 and are likely to cause wind noise.

[0106] Specifically, for example, if the predominant vibration mode of the balusters 12 is the secondary vibration mode in the range of wind speeds that commonly act on the vertical lattice handrail 10 and are likely to cause wind noise, four wind noise reduction devices 14G are arranged inside the balusters 12, as in the example of Figure 11. In this case, the length dimension L3 of the wind noise reduction devices 14G is set to one-fourth the length dimension L1 of the balusters 12 or slightly shorter than that.

[0107] For this reason, as shown in Fig. 13, the boundary between the first and second wind noise reduction devices 14G from the top is located near peak P2 of the amplitude in the secondary vibration mode, and the boundary between the third and fourth wind noise reduction devices 14G from the top is located near peak P3.

[0108] This makes it easier for each wind noise reduction device 14G to deform in response to deformation of the balusters 12 due to vibration in the secondary vibration mode than if a single wind noise reduction device with the same cross-sectional configuration as the wind noise reduction device 14G and a length dimension spanning almost the entire length of the balusters 12 were placed inside the balusters 12. Also, because the amount of deformation per wind noise reduction device 14G is smaller than when a single wind noise reduction device as described above is placed inside the balusters 12, it is easier for each wind noise reduction device 14G to deform in response to deformation of the balusters 12 due to vibration.

[0109] 11, the boundary between the second and third wind noise reduction devices 14G from the top is located near the amplitude peak P1 (see FIG. 4) in the primary vibration mode. For this reason, each wind noise reduction device 14G is likely to deform in response to deformation of the balusters 12 caused by vibration in the primary vibration mode.

[0110] Therefore, by setting the length L3 and number of the wind noise reduction devices 14G as described above, it is possible to improve the performance of reducing wind noise through frictional damping.

[0111] Furthermore, for example, if the predominant vibration mode of the balusters 12 within a specified wind speed range is the primary vibration mode, two wind noise reduction devices 14G may be placed inside the balusters 12, and the length dimension L3 of the wind noise reduction devices 14G may be set to be the same as or slightly shorter than the length dimension L1 of the balusters 12, i.e., half the length dimension L1.

[0112] Furthermore, the length dimension L3 and number of wind noise reduction devices 14G are not limited to being set as described above. For example, one of the four wind noise reduction devices 14G in the example of Fig. 11 may be omitted, or only one wind noise reduction device 14G may be placed inside the balusters 12. In either case, the effect of reducing wind noise through frictional damping can still be achieved.

[0113] Furthermore, multiple wind noise reduction devices 14G having length dimensions other than the length dimension corresponding to the predominant vibration mode of the balusters 12 in a predetermined wind speed range may be arranged inside the balusters 12. Even in this case, the amount of deformation per wind noise reduction device 14G is smaller than when a single wind noise reduction device having the same cross-sectional configuration as the wind noise reduction device 14G and a length dimension spanning almost the entire length of the balusters 12 is arranged inside the balusters 12, and therefore the wind noise reduction devices 14G are more likely to follow deformation of the balusters 12 due to vibration. This makes it possible to improve the performance of reducing wind noise through frictional damping.

[0114] [Ninth embodiment] Next, a ninth embodiment, which is a partial modification of the eighth embodiment described above, will be described.

[0115] In the ninth embodiment, as shown in FIG. 14, a wind noise reduction device 14G similar to that in the eighth embodiment is disposed inside a balusters 12A.

[0116] The balusters 12A are hollow members with a hourglass-shaped cross section. The balusters 12A are configured such that the pair of outer wall surfaces 12c and the pair of inner wall surfaces 12e of the balusters 12 of the first embodiment described above are replaced with a pair of outer wall surfaces 12h and a pair of inner wall surfaces 12i, respectively.

[0117] In the cross section of balusters 12A, outer wall surface 12h and inner wall surface 12i are formed in a V-shape that slopes inward toward the center in the depth direction of balusters 12A. At the center portion in the depth direction of inner wall surface 12i, curved surface 12ia is formed that curves convexly toward the inside of balusters 12A.

[0118] The wind noise reduction device 14G is arranged inside the balusters 12 so that the contact surfaces 83a, which are the outer surfaces of the curved plate portions 83 of both plate members 81, are in close contact with the curved surfaces 12ia of both inner wall surfaces 12i of the balusters 12.

[0119] In the ninth embodiment, the leaf spring 31 of the wind noise reduction device 14G has a spring force that keeps the contact surfaces 83a of both plate members 81 in constant contact with the curved surface 12ia of the inner wall surface 12i, and that exerts a pressing force that allows the plate members 81 to slide against the curved surface 12ia when the balusters 12A are deformed.

[0120] In the ninth embodiment, as in the eighth embodiment, the length dimension L3 of the wind noise reduction device 14G and the number of wind noise reduction devices 14G arranged inside the balusters 12A are set, for example, according to the dominant vibration mode within a predetermined wind speed range of the balusters 12. This makes it possible to improve the performance of reducing wind noise through frictional damping.

[0121] In the ninth embodiment, as in the eighth embodiment, the length dimension L3 and number of the wind noise reduction devices 14G are not limited to being set as described above. Furthermore, multiple wind noise reduction devices 14G having length dimensions other than those corresponding to the predominant vibration mode of the balusters 12A within a predetermined wind speed range may be arranged inside the balusters 12A.

[0122] [Hammering test] Next, a hammering test conducted on the wind noise reduction devices 14, 14A to 14E of the first to sixth embodiments described above will be described.

[0123] In this hammering test, a balusters 12 was used, which was made of an aluminum tubular member and had a width (lateral width), depth, thickness and length of 20 mm, 30 mm, 1 mm and 1000 mm, respectively.

[0124] Hammering tests were then conducted on cases where each of the wind noise reduction devices 14, 14A to 14E of the first to sixth embodiments was installed. For the wind noise reduction device 14B of the third embodiment, hammering tests were also conducted on a device where fluororesin tape was attached to the contact surface 22a of the plate member 22 (with fluororesin tape). For comparison, hammering tests were also conducted on a balusters 12 on which none of the wind noise reduction devices 14, 14A to 14E was installed (balusters 12 without measures).

[0125] The wind noise reduction devices 14, 14A to 14E of the first to sixth embodiments used in this hammering test were all made of ABS.

[0126] The length L2 of the plate members 22 of the wind noise reduction devices 14 to 14E of the first to sixth embodiments used in this hammering test was 1000 mm, and the thickness of the leaf springs 24, 31, 36, 41, 46, 51 was 0.7 mm. The width of the plate members 22 of the wind noise reduction devices 14 to 14D of the first to fifth embodiments was 27.2 mm, and the width of the plate member 22 of the wind noise reduction device 14E of the sixth embodiment was 27.38 mm.

[0127] For the wind noise reduction devices 14, 14A, and 14B of the first to third embodiments, hammering tests were conducted on plates 22 with thicknesses t of 1 mm and t of 2 mm. For the wind noise reduction device 14B of the third embodiment with fluororesin tape attached (with fluororesin tape) and the wind noise reduction device 14D of the fifth embodiment, hammering tests were conducted on plates with thickness t of 2 mm. For the wind noise reduction devices 14C and 14E of the fourth and sixth embodiments, hammering tests were conducted on plates with thickness t of 1 mm.

[0128] In this hammering test, vibrations in the primary and secondary vibration modes were evaluated.

[0129] By conducting this hammering test, the damping constant of the balusters 12 was estimated. The damping constant can be used as an index of the level of the ability to attenuate vibrations occurring in the balusters 12 (damping capacity), that is, the level of the ability to suppress vibrations of the balusters 12. The larger the damping constant value, the higher the damping capacity. The damping constant can be estimated from the excitation force and acceleration applied to the balusters 12 in the hammering test.

[0130] The results of the hammering test are shown in Fig. 15. In Fig. 15, "plate thickness" indicates the thickness t of the plate member 22.

[0131] 15, the balusters 12 on which the wind noise reduction devices 14, 14A to 14E of the first to sixth embodiments are installed have a higher damping constant than the balusters 12 on which no countermeasures are taken. This shows that the balusters 12 on which the wind noise reduction devices 14, 14A to 14E are installed contribute to reducing noise (wind noise) generated by wind acting on the vertical lattice handrail 10.

[0132] [Wind tunnel experiment] (Wind tunnel experiments on the first to fifth embodiments) Next, a wind tunnel experiment conducted on the wind noise reduction devices 14, 14A to 14D of the first to fifth embodiments described above will be described.

[0133] In this wind tunnel experiment, we used a vertical lattice handrail 10 with ten balusters 12 similar to those used in the hammering test described above, and a vertical lattice handrail 10 with five similar balusters 12. In both vertical lattice handrails 10, the balusters 12 were spaced 60 mm apart.

[0134] Using a vertical lattice handrail 10 with ten of the above-mentioned balusters 12 arranged thereon, wind tunnel tests were conducted for a case in which each of the wind noise reduction devices 14, 14A, 14B of the first to third embodiments was attached to the balusters 12, and a case in which no countermeasures were used for the balusters 12. Here, the wind noise reduction devices 14, 14A, 14B of the first to third embodiments used were those used in the above-mentioned hammering tests, with the plate members 22 having a thickness t of 2 mm.

[0135] Furthermore, using a vertical lattice handrail 10 with five of the above-mentioned balusters 12 arranged, wind tunnel experiments were conducted for cases in which each of the wind noise reduction devices 14B to 14D of the third to fifth embodiments was attached to the balusters 12, and for cases in which balusters 12 without any countermeasures were used. Here, the wind noise reduction devices 14B to 14D of the third to fifth embodiments were the same as those used in the above-mentioned hammering tests. For the wind noise reduction device 14B of the third embodiment, plate members 22 with thicknesses t = 1 mm, t = 2 mm, and t = 2 mm plate members 22 with fluororesin tape attached (with fluororesin tape) were used.

[0136] In this wind tunnel experiment, wind at a speed of 3 to 20 m / s was blown from the front to the back of the vertical lattice handrail 10. Then, the A-weighted sound pressure level and the vibration acceleration level in the direction perpendicular to the wind (horizontal direction) were measured.

[0137] Figures 16 and 17 show the measurement results of the A-weighted sound pressure level and the vibration acceleration level in the direction perpendicular to the wind in a wind tunnel experiment conducted using a vertical lattice handrail 10 with ten of the above-mentioned balusters 12. Figures 18 and 19 show the measurement results of the A-weighted sound pressure level and the vibration acceleration level in the direction perpendicular to the wind in a wind tunnel experiment conducted using a vertical lattice handrail 10 with five of the above-mentioned balusters 12.

[0138] As shown in Figures 16 and 17, when wind noise reduction devices 14, 14A, and 14B were installed on a vertical lattice handrail 10 with ten balusters 12, the A-weighted sound pressure level and the vibration acceleration level in the direction perpendicular to the wind were lower than when no countermeasures were taken, confirming the effect of reducing wind noise.

[0139] Here, as shown in FIG. 17, it was confirmed that the greater the number of times the leaf springs 24, 31, 36 of the wind noise reduction devices 14, 14A, 14B are bent, the lower the level of vibration acceleration in the direction perpendicular to the wind and the greater the effect of reducing wind noise.

[0140] Furthermore, as shown in Figures 18 and 19, when wind noise reduction devices 14B to 14D were installed on a vertical lattice handrail 10 with five balusters 12, the A-weighted sound pressure level and the vibration acceleration level in the direction perpendicular to the wind were lower than when no countermeasures were taken, confirming the effect of reducing wind noise.

[0141] (Wind tunnel experiment on the eighth embodiment) Next, a wind tunnel experiment conducted on the wind noise reduction device 14G of the above-described eighth embodiment will be described.

[0142] In this wind tunnel experiment, a vertical lattice handrail 10 was used, which consisted of 15 balusters 12 made of aluminum tubular members with width (horizontal width), depth, thickness and length of 15 mm, 30 mm, 1 mm and 1100 mm, arranged with a center-to-center spacing of 60 mm.

[0143] Wind tunnel tests were conducted on cases where multiple wind noise reduction devices 14G were attached to each balusters 12 of this vertical lattice handrail 10. Specifically, wind tunnel tests were conducted on the following cases: when two wind noise reduction devices 14G with L3 = 542.5 mm were attached to each balusters 12 (542.5 x 2), when three wind noise reduction devices 14G with L3 = 361.6 mm were attached (361.6 x 3), when four wind noise reduction devices 14G with L3 = 271.3 mm were attached (271.3 x 4), when six wind noise reduction devices 14G with L3 = 180.8 mm were attached (180.8 x 6), and when three wind noise reduction devices 14G with L3 = 271.3 mm were attached (271.3 x 3). For comparison, wind tunnel experiments were also conducted on a case where one wind noise reduction device 14G with L3 = 1085 mm was attached to each balusters 12 (1085 x 1), and on a case where balusters 12 without any countermeasures were used.

[0144] Here, in the case of 271.3×3, three wind noise reduction devices 14G are arranged side by side from the vicinity of the lower end of the balusters 12 without any gaps between them.

[0145] In each of the above cases, the wind noise reduction device 14G used had a plate member 81 with a thickness t of 0.9 mm.

[0146] In this wind tunnel experiment, wind with a speed of 3 to 20 m / s was blown from the front side of the vertical lattice handrail 10 at a wind direction of 0°. Then, the A-weighted sound pressure level and vibration acceleration level were measured. The measurement results of the A-weighted sound pressure level and vibration acceleration level are shown in Figure 20 and Figure 21, respectively.

[0147] As shown in Figure 20, when multiple wind noise reduction devices 14G were attached to each balusters 12, the A-weighted sound pressure level was lower than when no measures were taken, confirming the effect of reducing wind noise. With 542.5 x 2, wind noise was detected at wind speeds of 7 and 8 m / s, just as with 1085 x 1, but in the other cases, wind noise was barely detected.

[0148] Furthermore, as shown in Figure 21, when multiple wind noise reduction devices 14G were attached to each balusters 12, the vibration acceleration level was lower than when no measures were taken, confirming the effect of reducing wind noise. Also, the more wind noise reduction devices 14G attached to the balusters 12, the lower the vibration acceleration level tends to be, but the vibration acceleration level was lower with 271.3 x 4 than with 180.8 x 6, with 271.3 x 4 showing the best results.

[0149] Here, with the balusters 12 used in this wind tunnel testing, the predominant vibration mode is the secondary vibration mode in the wind speed range of approximately 6 to 9 m / s, which includes 7 and 8 m / s, at which wind noise was confirmed with the 542.5 x 2 and 1085 x 1 designs, as described above. With the 271.3 x 4 design, as in the example of Figure 13 described above, the boundary between the first and second wind noise reduction devices 14G from the top is located near peak P2 of the amplitude in the secondary vibration mode, and the boundary between the third and fourth wind noise reduction devices 14G from the top is located near peak P3. For this reason, it is thought that the 271.3 x 4 design showed the best results.

[0150] [Other embodiments] As described above, the present invention has been described with reference to the first to ninth embodiments, but the descriptions and drawings that form part of this disclosure should not be understood as limiting the present invention. Various alternative embodiments, examples, and operating techniques will become apparent to those skilled in the art from this disclosure.

[0151] The leaf spring of the wind noise reduction device may have a shape other than those shown in the first to ninth embodiments.

[0152] For example, in the first to fifth and seventh to ninth embodiments described above, examples have been shown in which the leaf springs 24, 31, 36, 41, 46, and 62 are bent multiple times, but the leaf springs may be bent only once.

[0153] In the first to fifth, eighth, and ninth embodiments, the bent portions 24b and 24c of the leaf spring 24, the bent portions 31d to 31g of the leaf spring 31, the bent portions 36e to 36i of the leaf spring 36, the bent portions 31d to 31g of the leaf spring 41, and the bent portions 31d to 31g of the leaf spring 46 are curved in an arc shape. However, the shape of the bent portions is not limited to this. For example, the bent portion between two flat plate portions may be U-shaped or may be curved in a shape other than an arc. Also, for example, in a leaf spring having a plurality of bent portions between two flat plate portions, some of the bent portions may be curved and the remaining bent portions may be U-shaped. Also, for example, the bent portion connecting the plate member 22 and the flat portion of the plate spring may be replaced with a flat plate that is not parallel to the plate member 22 and the flat portion of the plate spring, and this flat plate may be used to connect the plate member 22 and the flat portion of the plate spring.

[0154] Furthermore, at least some of the connecting portions 62d to 62g of the leaf spring 62 of the seventh embodiment may be formed in a curved shape.

[0155] In the first to fifth, eighth and ninth embodiments described above, the flat plate portion 24a of the leaf spring 24, the flat plate portions 31a to 31c of the leaf spring 31, the flat plate portions 36a to 36d of the leaf spring 36, the flat plate portions 31a, 31c, 41a, 41b of the leaf spring 41, and the flat plate portions 31a to 31c of the leaf spring 46 are parallel to the plate member 22. However, this is not limiting, and for example, the flat plate portions of the leaf springs may be inclined relative to the plate member 22. Furthermore, in a leaf spring having a plurality of flat plate portions, flat plate portions parallel to the plate member 22 and flat plate portions inclined relative to the plate member 22 may be combined.

[0156] In the seventh embodiment, the flat plate portions 62a to 62c of the leaf spring 62 are parallel to the side wall 71 of the hollow member 61. However, this is not limiting, and for example, at least one of the flat plate portions 62a to 62c may be inclined with respect to the side wall 71.

[0157] In the first to sixth embodiments described above, the plate member 22 has a length that allows it to abut against the inner wall surface 12e of the balusters 12 at the peak of the amplitude of the vibrations that occur when the balusters 12 vibrate in one or more of the primary, secondary, and tertiary vibration modes. However, other length dimensions are also acceptable as long as frictional damping occurs. However, using the above length dimensions can further improve the performance of reducing wind noise. The same applies to the hollow member 61 in the seventh embodiment.

[0158] In the first to sixth embodiments described above, the balusters 12 have a rectangular cross-sectional shape (transverse cross-sectional shape), and the plate members 22 are made of flat plates. Furthermore, in the ninth embodiment, the balusters 12A have an hourglass-shaped cross-sectional shape, and the plate members 81 have a shape that includes a curved plate portion 83 in part, corresponding to the cross-sectional shape of the balusters 12A (the shape of the inner wall surfaces 12i). However, the cross-sectional shape of the balusters is not limited to rectangular and hourglass-shaped, and may be, for example, a polygon other than rectangular (triangle, trapezoid, pentagon, etc.), a rounded rectangle, a streamlined shape (wing shape, etc.), a spindle shape, a sector shape, a circle, a semicircle, an ellipse, a T-shape, etc. Furthermore, the plate members of the wind noise reduction device are not limited to those having a shape corresponding to the cross-sectional shape of the flat and hourglass-shaped balusters. For example, the plate members may have a bent shape, a curved shape, an uneven shape, etc., that matches the shape of the inner wall surfaces of the balusters.

[0159] Furthermore, in the first embodiment described above, one wind noise reduction device 14 was arranged inside the balusters 12, but as with the eighth and ninth embodiments, multiple wind noise reduction devices 14 may be arranged inside the balusters 12 along the extension direction of the balusters 12. The same applies to the wind noise reduction devices 14A to 14F in the second to seventh embodiments.

[0160] As such, the present invention naturally includes various embodiments not described herein. Therefore, the technical scope of the present invention is defined only by the invention-specifying matters according to the scope of the claims that are appropriate from the above description. [Explanation of symbols]

[0161] 10 Vertical lattice handrail 12,12A Baluster 12e, 12f, 12i Inner wall surface 12ia curved surface 14, 14A to 14G Wind noise reduction device 22,81 Plate members 82 Flat plate part 83 Curved plate section 22a,71a,82a,83a Contact surface 24, 31, 36, 41, 46, 51, 62 Leaf springs 61 Hollow members 71,72 side wall

Claims

1. A wind noise reduction device applied to a lattice structure consisting of a handrail or fence with a plurality of hollow balusters, a pair of plate members facing each other and disposed inside each balusters, the pair of plate members extending in the extension direction of the balusters inside the balusters; a leaf spring disposed between the two plate members and extending over the entire length of the two plate members in the longitudinal direction; The leaf spring ensures that the entire surfaces of both plate members that contact the inner wall surfaces of the balusters are always in contact with the inner wall surfaces, and when the balusters are deformed, the leaf spring exerts a pressing force that allows the plate members to slide against the inner wall surfaces. This is a wind noise reduction device.

2. 2. The wind noise reduction device according to claim 1, wherein the leaf spring is formed integrally with both plate members.

3. 3. The wind noise reduction device according to claim 1, wherein both plate members and the leaf spring are made of resin.

4. The wind noise reduction device according to claim 1 or 2, wherein the balusters have a rectangular cross-sectional shape.

5. 3. The wind noise reduction device according to claim 1, wherein the leaf spring is bent at least once in a short direction perpendicular to the extending direction of the balusters.

6. 3. The wind noise reduction device according to claim 2, wherein the leaf springs are connected to one of the plate members and the other of the plate members at positions offset from each other in the width direction of the plate members.

7. 7. The wind noise reduction device according to claim 6, wherein the leaf spring is formed of a flat plate connecting one end of one of the plate members in the width direction to the other end of the other of the plate members in the width direction.

8. A balusters used in the manufacture of a lattice structure consisting of a handrail or fence, a hollow tubular member; A balusters comprising the wind noise reduction device according to claim 1 or 2, disposed inside the tubular member.

9. The balusters according to claim 8 , wherein a plurality of the wind noise reduction devices are arranged along the extending direction of the balusters.

10. 9. The balusters according to claim 8, wherein the wind noise reduction device has a length dimension corresponding to a dominant vibration mode of the balusters in a predetermined range of wind speeds.

11. 10. The balusters according to claim 9, wherein the wind noise reduction devices are arranged in a number and with length dimensions according to a predominant vibration mode of the balusters in a predetermined wind speed range.

12. A lattice structure consisting of a handrail or fence having a plurality of balusters, A grid-like structure, each of which comprises a baluster according to claim 8.

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