JP3512510B2 - Speaker stand - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a speaker stand that holds a speaker.

[0002]

2. Description of the Related Art In a speaker stand for holding a speaker, it is desired to mount the speaker without impairing the original sound quality of the speaker. Therefore, various techniques have been conventionally developed. Japanese Utility Model Application Laid-Open No. 3-34387 discloses a technique relating to a speaker stand filled with a foam material by foaming and solidifying an undiluted solution of the foam material in a hollow chamber of a metal pipe that supports the speaker. Japanese Utility Model Laid-Open No. 103403/1993 discloses a technique relating to a speaker stand that uses a damping steel plate having a sandwich structure in which the front and back sides of a resin sheet material are sandwiched by steel plates on a mounting table on which a speaker is mounted. Japanese Unexamined Patent Publication No. 6-237088 discloses a layer made of a medium-quality fiberboard using a damping layer in which metal powder particles of aluminum, copper, steel, cast iron or the like are bonded with a resin binder such as epoxy resin or phenol resin. Discloses a technique of forming a speaker stand using a hard board member sandwiching a damping layer. Japanese Unexamined Patent Publication No. 5-49519 discloses a technique of using a pointed tip with a pointed tip and supporting the speaker stand on the floor via the pointed tip. According to this, the harmful vibration transmitted from the floor to the speaker stand is expected to be cut off.

Further, in Japanese Patent Publication No. 1-51237, a top plate on which a speaker is placed, legs for holding the top plate, and a base set on the floor are integrally formed of cast iron, and the top plate is also formed. There is disclosed a speaker stand in which a suspending member made of a cast iron block is integrally connected to the lower surface of the suspension and suspended, and the lower surface of the suspending member is brought close to reach the base. In this thing, the effect of suppressing harmful vibration by shifting the harmful resonance frequency by using the mass of the suspension member and removing it from the normal frequency range,
An effect of suppressing the maximum amplitude on the mounting board can be expected.

[0004]

Further, in the industrial world, development is underway to obtain better sound quality. The present invention further advances the technology relating to the speaker stand including the above-mentioned hanging member, and the common problem is to form a hollow chamber in the hanging member, and cast iron-based powder particles in the hollow chamber of the hanging member. It is an object to provide a speaker stand in which a good sound quality of a speaker can be obtained by inserting a body.

[0005]

According to a first aspect of the present invention, there is provided a speaker stand, which comprises a mounting board on which a speaker is mounted, legs for supporting the mounting board, and a suspending member suspended from the mounting board. The speaker stand is characterized in that the suspension member has a hollow chamber, and the hollow chamber is loaded with a large number of powders and granules whose main component is cast iron containing graphite. .

A speaker stand according to a second aspect of the present invention is a speaker stand including a mounting board on which a speaker is mounted, legs for supporting the mounting board, and a suspension member suspended from the mounting board. The suspending member has a first hollow chamber and the legs have a second hollow chamber. The first hollow chamber and the second hollow chamber are equipped with a large number of powdery or granular materials containing cast iron containing graphite as a main component. It is characterized by being included.

According to a third aspect of the present invention, there is provided a speaker stand in which a mounting board on which a speaker is mounted, legs for supporting the mounting board, a hanging member hung on the mounting board, and a stand mounting surface for holding the legs. A speaker stand having a first hollow chamber, a leg having a second hollow chamber, a base having a third hollow chamber, a first hollow chamber, and a second hollow chamber. Each of the hollow chamber and the third hollow chamber is characterized in that a large number of powdery particles containing cast iron containing graphite as a main component are charged therein.

A speaker stand according to a fourth aspect of the present invention is the speaker stand according to any one of the first, second and third aspects, wherein the speaker stand is provided with a pointed tip having a pointed tip, and is held on a stand installation surface via the pointed tip. It is what According to the present invention, the granular material containing cast iron containing graphite as a main component is charged in the hollow chamber. Cast iron powder can generally be used as the powder. As the cast iron, gray cast iron with flake graphite is particularly preferable, but in some cases, cast iron with spheroidal graphite, cast iron with agglomerated graphite, cast iron with eutectic graphite with a small grain size,
Cast iron with loose graphite, cast iron with caterpillar graphite, or cast iron with excessive quiche graphite may be used. As the cast iron matrix, an iron structure containing at least one kind of pearlite, ferrite, austenite, bainite and the like can be appropriately selected.

As the cast iron powder, cast iron powder particles exfoliated and dropped from the surface of the cast product can be used. In this case, when obtaining a cast iron product, shot materials such as shots and grit are projected onto the surface of the cast iron product (sand mold casting, mold casting), and the surface layer (generally the black skin layer) of the cast product is removed. Peeling,
Dropped particles can be used. In some cases, as the cast iron powder, atomized powder containing graphite and formed by atomizing molten cast iron in air or in a non-oxidizing atmosphere, and crushed powder obtained by mechanically crushing cast iron ingot may be used.

The particle size of the granular material can be appropriately selected according to the desired sound quality and the like, but in general, a granular material having a small average particle diameter can produce a damping effect although the damping effect can be secured. The powder tends to be harmful to the environment, and if the powder has a large average particle size, the vibration damping performance tends to be deteriorated, which is disadvantageous in improving the sound quality. Considering these points, the upper limit of the average particle size is 900 μm, 700 μm, 500 μm, 300 μm
The lower limit value can be set to 10 μm, 30 μm, and 50 μm, and therefore, particles having a particle size of generally 30 to 700 μm can be adopted. In addition, the above-mentioned powdery particles may be mixed with powdery particles of other species such as sand particles and steel particles.

It is generally preferable that the volume ratio of the powdery particles to the hollow chamber is large, but in consideration of other factors such as weight, the volume of the hollow chamber is 1/2 or more and 3/4 or more. 4 /
It can be 5 or more, and can be 1/2 or less in some cases. The volume ratio in which the powdery or granular material is charged may be the same in the first hollow chamber, the second hollow chamber and the third hollow chamber, or may be individually different.

[0012]

According to the first aspect of the present invention, the suspension member is suspended on the mounting board on which the speaker is mounted, and the hollow chamber of the suspension member has a large number of cast iron containing graphite as a main component. Granules are charged. According to the second aspect, not only the hollow chamber of the suspension member but also the second hollow chamber of the leg for holding the mounting board are charged with a large number of powdery or granular materials mainly containing cast iron containing graphite. There is.

According to the third aspect, not only the first hollow chamber of the suspension member and the second hollow chamber of the leg but also the third hollow chamber of the base holding the leg contains cast iron containing graphite as a main component. A large number of powder particles are charged. As described above, according to the present invention, a large number of powder particles containing cast iron containing graphite as a main component are charged in the hollow chamber, which is advantageous for obtaining good sound quality. The reason why good sound quality is obtained is that friction between cast iron-based powder particles containing graphite, boundary friction between the iron matrix and graphite inside the cast iron-based powder particles, and vibration damping of graphite itself contribute to it. It is considered that the vibration energy is attenuated by converting the vibration energy into heat energy, etc., and thereby the harmful vibrations on the mounting board or the leg on which the speaker is mounted are absorbed. Further, since it is loaded in the hollow chamber in the form of powder or granules, there are less restrictions on the movement of the powder or granules in the hollow chamber as compared with the case where the powder or granules are bonded and fixed with a binder. It is presumed that it has contributed.

By the way, if the harmful resonance frequency is removed from the normal frequency range of the speaker, the harmful resonance is reduced or avoided, which is advantageous for producing the sound of the speaker in a straightforward manner, and is effective for improving the sound quality. In the field of vibration, it is said that the resonance frequency is basically influenced by the mass of the vibration source. In this respect, according to claim 1, since the cast iron-based powder particles are loaded in the hollow chamber of the suspension member, the harmful resonance frequency is moved by the mass of the suspension member to be removed from the normal frequency range. It is advantageous to

Further, according to the first aspect, when the amount of the powder or granules charged in the hollow chamber of the suspension member is adjusted, the value of the resonance frequency is influenced as compared with the case where the suspension member is in a lump form. The advantage is that it can also contribute to adjusting the mass of the hanging member. Still further, according to claim 1, since the suspension member is suspended on the mounting board, the mass of the suspension member is loaded on the mounting board. Therefore, even when the harmful vibration is transmitted to the mounting board, it is advantageous to regulate the amplitude thereof. Therefore, according to claim 1, it is more advantageous to directly output the original sound of the speaker.

According to the second aspect of the present invention, since the cast iron-based powder particles are charged not only in the hollow chamber of the suspension member but also in the second hollow chamber of the leg, harmful vibrations in the leg are also effective. It can be absorbed, and in this sense as well, it is more advantageous to obtain a good sound inherent to the speaker. According to the third aspect, since the cast iron-based powder particles are also charged in the third hollow chamber of the base holding the legs, the harmful vibration transmitted from the stand installation surface to the speaker stand side is also effective. It can be absorbed, and in this sense as well, it is advantageous to obtain a good sound inherent to the speaker.

According to the present invention, the speaker stand is installed on the stand installation surface such as the floor through the pointed tip end, so that it is unnecessary from the stand installation surface such as the floor to the speaker stand side. It is advantageous to suppress or block the propagation of various harmful vibrations. Therefore, it is more advantageous to obtain good sound quality.

[0018]

EXAMPLES Examples of the present invention will be specifically described below. (Example 1) (Structure of Example) FIG. 1 is a perspective view of the whole, and FIG. 2 is a side view.

The speaker stand includes a top plate 1 as a mounting plate on which a speaker K functioning as a sound generator is placed, four vertically long legs 2 supporting the top plate 1, and lower end portions of the legs 2. It is provided with a base 3 to be held and a suspension member 5 suspended on the lower surface side of the top plate 1. The top plate 1 is made of steel, has a square plate shape, and is arranged substantially parallel to a floor surface W as a speaker installation surface. The top plate 1 includes a speaker mounting surface 10 on which the speaker K is mounted.

The leg 2 is arranged on the base 3 in an upright state. The leg 2 is formed of a steel pipe having a quadrangular cross section, and therefore has a vertically long cross section having a quadrangular cross section, that is, a second hollow chamber 20 extending in the direction of the arrow Y1. The second hollow chamber 20 of the leg 2 is charged with a large number of cast iron powders E as powdery particles containing cast iron containing graphite as a main component and is in a sealed state. The volume of the cast iron powder E charged into the second hollow chamber 20 is
Considering weight, sound quality, etc., the volume of the second hollow chamber 20 is set to 3/4 or more. 4 legs 2 each second
The hollow chamber 20 is charged with cast iron powder E in the same amount.

The legs 2 can contribute to the correspondence between the pitch position of the sound generated from the speaker K mounted on the top plate 1 and the pitch position of the user's ear. Therefore, in general, the length of the leg 2 is defined in consideration of such points. Foundation 3
Faces a floor surface W as a stand installation surface. Foundation 3
Is a steel substrate 30 that holds the lower end of each leg 2 and is parallel to the floor surface W, and a total of 2 steel substrates connected to both sides of the substrate 30.
The individual holding parts 32 are provided. The substrate 30 has a non-hollow structure, that is, a solid shape, and is arranged so as to float from the floor surface W. The holding portion 32 is in the shape of a square pipe and has a third hollow chamber 33 extending laterally, that is, in the direction of the arrow X1.
The arrow X1 direction is orthogonal to the arrow Y1 direction.

The same type of cast iron powder E containing graphite is also charged in the third hollow chamber 33 of the holding portion 32 to be in a hermetically sealed state. The volume of the cast iron powder charged in the third hollow chamber 33 is the third
The volume of the hollow chamber 33 is 3/4 or more. The holding portion 32 has an empty chamber 32i that is partitioned from the third hollow chamber 33 by a partition wall 32f. The hanging member 5 is the top plate 1.
It is vertically suspended in the central area of the lower surface of the. The suspension member 5 is formed of a steel pipe having a quadrangular cross section, and thus has a vertically elongated shape having a quadrangular cross section, that is, a first hollow chamber 50 extending in the arrow Y1 direction. The first hollow chamber 50 is filled with a large number of cast iron powders E as powdery particles containing cast iron containing graphite as a main component and is in a hermetically sealed state. The volume of the cast iron powder E charged into the first hollow chamber 50 is 3/4 or more of the volume of the first hollow chamber 50 in consideration of weight, desired sound quality, and the like.

The length of the suspension member 5 is about half of that of the leg 2, and the lower end 5f thereof is in a non-connected state with the substrate 30, that is, has a free end shape, and faces the substrate 30. The cast iron powder E according to this example has 3.0 to 3.8% by weight of carbon. The cast iron powder E is shot from a shot material such as a shot onto the surface layer of the cast iron product in the step of obtaining the cast iron product, and is separated and dropped from the surface layer of the cast product (generally a black skin layer). After that, sand particles and the like can be separated and used. Therefore, particles such as shots may be included in part. The particle size of such cast iron powder is generally within the range of 30 to 700 μm. In the above case, the waste can be effectively used.

A total of four pointed end portions 37 are provided on the lower portion of the holding portion 32. A lower portion 37c of the pointed end portion 37 has a conical shape or a substantially conical shape, and has a sharp tip and a small diameter. The pointed end portion 37 is placed in the recess 39i of the disk-shaped floor surface contacting device 39 (material: SUS303) that is in contact with the floor surface W. The floor surface contactor 39 also functions as a protection member that protects the floor surface W.

An example of the mounting structure of the leg 2 is shown in FIG. Figure 4
As shown in FIG. 5, the closing plates 25 are fixed to the upper and lower portions of the second hollow chamber 20 of the leg 2 in the longitudinal direction by welding or the like, whereby the cast iron charged in the second hollow chamber 20 is inserted. The powder E is sealed. Closure plate 2 in the longitudinal direction of leg 2
An attachment plate 26 is fixed to the outer side of 5 at a predetermined distance (ΔL) from the closing plate 25. The mounting plate 26 has screw holes 2
6h is formed. Then, by screwing the screw 29a inserted into the insertion hole 1m of the top plate 1 and the screw 29b inserted into the insertion hole 30m of the substrate 30 into the screw hole 26h,
The leg 2, the top plate 1 and the substrate 30 are integrated. The mounting plate 26
The closing plate 25 has a vertically symmetrical structure, so that the leg 2 can be vertically converted.

FIG. 5 shows an example of a mounting structure of the suspension member 5. As shown in FIG. 5, closing plates 55 are fixed to the upper and lower portions of the first hollow chamber 50 of the suspension member 5 in the longitudinal direction by welding or the like, so that the first hollow chamber 50 can be mounted in the first hollow chamber 50. The cast iron powder E that has been put in is sealed. Outside the closing plate 55 on the upper side of the hanging member 5, a predetermined distance (Δ
L2) The mounting plate 56 is fixed at a distance. Mounting plate 56
A screw hole 56h is formed in the insertion hole 1 of the top plate 1.
The suspension member 5 is suspended on the top plate 1 by screwing the screw 56t inserted through r into the screw hole 56h.

Here, as can be understood from FIG. 5, the screw 56t
By removing the, the hanging member 5 can be removed from the top plate 1.
Therefore, the suspension member 5 is detachable. It is to be noted that some kinds of suspension members 5 having different masses are easily prepared, and the speaker K
The hanging member 5 can be appropriately replaced depending on the situation. (Effect of Embodiment) As described above, according to this embodiment,
Since the cast iron powder E is charged in the first hollow chamber 50 of the suspension member 5, harmful vibrations (resonance, etc.) in the top plate 1 are suppressed, and the original sound of the speaker K can be directly emitted. It is advantageous.

By removing the harmful resonance frequency from the normal frequency range of the speaker K, the harmful resonance is reduced or avoided, which is advantageous for the sound of the speaker K to be output straight and effective for improving the sound quality. Here, in the field of vibration, if the spring constant of a portion supporting the vibration source is K and the mass of the vibration source supported by the portion is M, the resonance frequency is basically determined by M and K. It is said.

According to this embodiment, since the cast iron powder is charged in the first hollow chamber 50 of the suspension member 5, the harmful resonance frequency is shifted by the mass of the suspension member 5 and the normal frequency range is used. It is advantageous to remove from. Further, according to this embodiment,
If the amount of the cast iron powder E charged into the first hollow chamber 50 of the suspension member 5 is adjusted, the mass of the suspension member 5 that affects the resonance frequency as compared with the case where the suspension member 5 is a lump. It is also advantageous to adjust. Moreover, when fine adjustment of the mass of the suspension member 5 is desired, it is easy to adjust the charging amount of the cast iron powder E before the closing by the closing plate 25. Therefore, it is possible to use a mode in which the mass of the suspension member 5 is finely adjusted according to the type of the speaker or the preference of the user. Furthermore, since the suspension member 5 is suspended on the top plate 1,
The mass of the suspension member 5 is loaded on the top plate 1, the vibration amplitude of the top plate 1 is regulated, and the harmful vibration in the top plate 1 is regulated.
This is even more advantageous for producing the original sound of the speaker K in a straightforward manner.

Further, according to the present embodiment, since the suspension member 5 is suspended in the central region of the top plate 1 where the maximum amplitude is likely to occur, there is an advantage that the amplitude regulation effect in the top plate 1 can be easily secured. To be In addition, according to the present embodiment, since the cast iron powder E is charged not only in the first hollow chamber 50 of the suspension member 5 but also in the second hollow chamber 20 of the leg 2, the harmful vibration in the leg 2 ( (Resonance, etc.) is further suppressed, and it is more advantageous to directly output the original sound of the speaker K.

Further, according to this embodiment, since the cast iron powder E is also charged in the third hollow chamber 33 of the base 3 holding the leg 2, not only the harmful vibration of the base 3 itself can be suppressed,
The harmful vibrations transmitted from the floor surface W to the speaker stand can be absorbed, which is more advantageous for producing the original sound of the speaker K obediently. Further, since the cast iron powder E is charged also in the third hollow chamber 33 of the lower base 3, the center of gravity of the speaker stand is easily shifted downward, which can contribute to stabilizing the speaker stand.

Furthermore, according to this embodiment, since the base 3 is held on the floor W through the pointed tip portion 37 having a sharp tip, the harmful vibration is propagated from the floor W to the speaker K. It is even more advantageous to suppress this. Moreover, as can be understood from FIG. 1, since the tip end portion 37 and the cast iron powder E of the third hollow chamber 33 are arranged in series with respect to the vibration transmitted from the floor surface W, both vibrations are blocked. A function can be expected, which is advantageous for preventing vibration transmission from the floor surface W. Therefore, it is even more advantageous for producing the original sound of the speaker K in a straightforward manner.

In addition, according to this embodiment, a total of four legs 2 are provided.
Are distributed over the top plate 1, which is advantageous for reducing vibration unevenness on the top plate 1, and is also advantageous for improving sound quality in this sense. According to this embodiment, the suspension member 5
First hollow chamber 50, second hollow chamber 20 of leg 2, holding portion 32
Since the cast iron powder E is sealed and charged in the third hollow chamber 33, the cast iron powder E is shielded from the outside air, which is advantageous for suppressing the oxidation and corrosion of the cast iron powder E with time. Therefore, deterioration due to oxidation and corrosion of the cast iron powder E, fluctuations in particle size, and the like can be suppressed, which is advantageous in maintaining the sound quality of the speaker K for a long period of time.

(Second Embodiment) FIG. 6 is a perspective view of a speaker stand according to a second embodiment. The speaker stand according to this example has basically the same configuration as that of the speaker stand according to the first embodiment, and portions having the same functions are designated by the same reference numerals. Also in this example, the cast iron powder E is charged in the first hollow chamber 50 of the suspension member 5 and the second hollow chamber 20 of the leg 2.

However, the base 3 is composed only of the substrate 30, and the tip portions 37 are provided at the four corners of the substrate 30, respectively. The lower portion 37c of the tip end portion 37 as in the first embodiment
Has a conical shape with a sharp tip. The pointed tip portion 37 is in contact with the floor surface W, and is a disc-shaped floor surface contact tool 39.
Is placed in the recess 39i. Also in this example, the same effect as that of the first embodiment can be obtained.

(Test Example) A test for measuring the vibration damping property of the speaker stand according to the above-described Example 1 was conducted. Regarding the size of the speaker stand used, the top plate 1 has a width of 200 mm and a length of 250 m.
m and thickness 3.2 mm. The pipes that make up leg 2 are 4
The length is 0 mm □, the length is 450 mm, and the thickness is 1.6 mm. The pipe that constitutes the holding portion 32 is 50 mm square, the length is 270 mm, and the thickness is 3.2 mm. The pipe constituting the suspension member 5 is 40 mm □, the length is 150 mm, and the thickness is 1.6 mm.

In this test, as shown in FIGS. 7 and 8,
A first acceleration pickup 61 is provided on the end side of the back surface of the top plate 1,
A second acceleration pickup 62 is attached to the side surface of the middle region of the leg 2, and an electromagnetic exciter 63 is attached to the end of the speaker mounting surface 10 of the top plate 1 opposite to the first acceleration pickup 61. The signal from the first acceleration pickup 61 is the signal line 61w.
The signal from the second acceleration pickup 62 is input to the analysis device 64 via the signal line 62w. The electromagnetic exciter 63 is controlled by the control device 65 via the signal line 63w.

Then, the electromagnetic exciter 63 is operated, and the vibration generated on the top plate 1 is measured by the first acceleration pickup 61,
The vibration generated in the leg 2 is measured by the second acceleration pickup 62. The detected vibration is subjected to FFT analysis, and the vibration characteristics of the top plate 1 and the legs 2 are detected in a predetermined frequency region (0 to 10 kHz: one in which the audible sound region is considered). As Comparative Example 1, the first hollow chamber 50 of the suspension member 5 and the second hollow chamber 2 of the leg 2
0 and the third hollow chamber 33 of the holding part 32 was measured without charging the cast iron powder E.

Further, as Test Example 1, cast iron powder E is provided in both the first hollow chamber 50 of the suspension member 5 and the second hollow chamber 20 of the leg 2.
Was charged, but the third hollow chamber 33 of the holding portion 32 was measured without charging the cast iron powder E. In Test Example 1, the charging amount of the cast iron powder E is about the same as the volume of the first hollow chamber 50 and about the same as the volume of the second hollow chamber 20.

Further, as Test Example 2, the first hollow chamber 50 of the suspension member 5, the second hollow chamber 20 of the leg 2, and the third hollow chamber 30 of the holding portion 32.
The measurement was performed with the cast iron powder E charged in the hollow chamber 33. The amount of the cast iron powder E charged is approximately the same as the volume of the first hollow chamber 50, approximately the same as the volume of the second hollow chamber 20, and approximately the same as the volume of the third hollow chamber 33. is there. FIG. 9 shows the measurement results according to Comparative Example 1. Here, FIG. 9A shows the vibration characteristic of the top plate 1, and FIG. 9B shows the vibration characteristic of the leg 2. 9A and 9B, the horizontal axis represents frequency and the vertical axis represents vibration level (dB). On the vertical axis, the maximum peak PA of the vibration of the top plate 1 when the cast iron powder E was not charged was set to the reference value (0 dB). This means that the vibration is reduced and the sound quality is improved toward the −50 dB side of the vertical axis.

FIG. 10 shows Test Example 1, that is, the first hollow chamber 5.
0, the result when the cast iron powder E is charged in the second hollow chamber 20 is shown. Here, FIG. 10A shows the vibration characteristic of the top plate 1, and FIG. 10B shows the vibration characteristic of the leg 2. As can be understood from the comparison between the characteristics of FIG. 9 (A) and the characteristics of FIG. 10 (A), according to FIG. 10 (A), the vibration of the top plate 1 is reduced particularly in the vicinity of the frequency range of 1 kHz to 4 kHz. You can see that As can be understood from the comparison between the characteristics of FIG. 9B and the characteristics of FIG.
According to FIG. 10 (B), it can be seen that the vibration of the leg 2 is reduced over the entire measured frequency range.

FIG. 11 shows Test Example 2, that is, the first hollow chamber 5.
0, the second hollow chamber 20 and the third hollow chamber 33 show the results when the cast iron powder E is charged respectively. Figure 11
FIG. 11A shows the vibration characteristic of the top plate 1, and FIG.
Indicates a vibration characteristic of the leg 2. As can be understood from a comparison between the characteristics of FIG. 9A and the characteristics of FIG.
1 (A) shows that the vibration of the top plate 1 is reduced in the frequency range of 1 kHz to 4 kHz. According to FIG. 11 (B), it can be seen that the vibration of the leg 2 is reduced over the entire measured frequency range.

Further, the cast iron powder E used in the above examples
A damping test was performed to evaluate the damping property of. According to this attenuation test, although not shown, a pipe-shaped test piece (square pipe:
550 mm × 25 mm × 25 mm × thickness 1.6 mm), the above-mentioned pipe-shaped hollow chamber is charged with the above-mentioned cast iron powder E, and one end of the horizontally arranged pipe-shaped test piece is fixed with a vise, In that state, a vibrator and an acceleration pickup were attached to the other end of the pipe-shaped test piece. Then, the resonance frequency was set and the other end of the pipe-shaped test piece was vibrated by operating the vibration exciter at that frequency. Then, the damping characteristic after stopping the vibration by turning off the power of the shaker was detected by the acceleration pickup, and the decay waveform was measured by the oscilloscope to obtain the logarithmic decay rate λ. The logarithmic decay rate λ was calculated from the following equation (1).

Logarithmic attenuation rate λ = [ln (a / b)] / (f × t) (1) where a is the amplitude of the attenuation start point in the attenuation waveform, and b is the excitation stop point in the attenuation waveform. The amplitude after a predetermined time has elapsed, f is the resonance frequency [Hz], and t is the time from a to b [sec]. Further, as a comparative example, a pipe-shaped test piece loaded with sand and a pipe-shaped test piece loaded with lead powder were used to measure the attenuation characteristics in the same manner, and the same test was conducted three times for each test piece. The average value of the logarithmic decay rate λ was obtained.

According to these test results, the pipe-shaped test piece charged with the cast iron powder E had a logarithmic decrement λ of 0.270.
It was 0. The pipe-shaped test piece charged with sand had a logarithmic decrement λ of 0.1682. In the pipe-shaped test piece charged with the lead powder, the logarithmic decrement λ was 0.1924. Thus, it was found that the cast iron powder E is more effective in damping vibration than the sand or lead powder.

It is speculated that this is because the powder particles of the cast iron powder E are a kind of composite material in which soft graphite is contained in a relatively hard iron matrix. On the other hand, the sand particles as a whole are mainly composed of oxides such as silicon and aluminum, and these oxides are quite hard with Hv hardness of 1000 or more. The lead particles are basically formed of soft lead particles.

(Other Examples) In the above embodiment, the suspension member 5 is used.
However, the number is not limited to this, and 2
It can be three, four, or more. Hanging member 5
The cross-sectional shape of is not limited to a square shape, but may be another angular shape or a circular shape. In the embodiment described above, the suspension member 5
Is about half the length of the leg 2, but the length is not limited to this and may be extended so as to approach the substrate 30. In short, the lower end of the suspension member 5 may be a free end. Further, in the above-mentioned example, the suspension member 5 is suspended in the central region of the top plate 1, but the present invention is not limited to this, and any other region may be used as long as the top plate 1 is used.

Although the number of legs 2 is four in the above embodiment,
It is not limited to this, but one, two, three, five
It can be a book. The cross-sectional shape of the leg 2 is not limited to the quadrangular shape, but may be another angular shape or a circular shape. In the first embodiment described above, the holding portion 32 has a structure in which the cast iron powder E is charged into the third hollow chamber 33, but the holding portion is not limited to this, and the holding portion is made of metal lumps such as cast iron or is formed by sheet metal. It is also a good part.

First hollow chamber 50, second hollow chamber 20 and third hollow chamber
If the hollow chamber 33 is made a non-oxidizing atmosphere such as a nitrogen atmosphere,
It is possible to further contribute to the long-term storage of the cast iron powder E, and it is advantageous for exhibiting the function of the speaker stand according to this embodiment satisfactorily for a long time. In addition, the present invention is not limited to the embodiments described above and shown in the drawings. For example, the material of the suspension member, the legs, the top plate, the substrate, etc., which are the elements constituting the speaker stand, is limited to steel. The leg 2 is not limited to the upright state but may be in an upright state with an inclination, and the carbon content of the cast iron powder E is not limited to the above range. , Can be appropriately selected as necessary within the scope of the invention.

(Supplementary Note) The following technical idea can be understood from the above-described embodiment. The speaker stand according to each claim, wherein the suspension member has a structure that can be attached to and detached from the mounting board. ○ The speaker stand according to each claim, wherein the legs are vertically convertible. The speaker stand according to each claim, wherein the hollow chamber is hermetically sealed by welding or the like. The speaker stand according to claim 2, wherein the second hollow chamber and the third hollow chamber are arranged in directions orthogonal to each other.

[Brief description of drawings]

FIG. 1 is an overall perspective view showing a part of a cross section according to a first embodiment.

FIG. 2 is a side view of the whole according to the first embodiment and showing a part of the cross section.

FIG. 3 is an overall configuration diagram showing a cross section of a main part according to the first embodiment.

FIG. 4 is a cross-sectional view showing an example of a leg and a leg attachment structure.

FIG. 5 is a cross-sectional view showing an example of a suspension member mounting structure.

FIG. 6 is an overall perspective view according to the second embodiment.

FIG. 7 is a plan view of a mode for testing vibration characteristics.

FIG. 8 is a side view showing a form for testing vibration characteristics together with a measuring device.

FIG. 9 is a graph showing vibration characteristics of a top plate and legs when cast iron powder E is not charged.

FIG. 10 is a graph showing vibration characteristics of a top plate and legs when cast iron powder E is charged in the first hollow chamber of the suspension member and the second hollow chamber of the legs.

FIG. 11 shows vibration characteristics of the top plate and the leg when the cast iron powder E is charged in both the first hollow chamber of the suspension member, the second hollow chamber of the leg, and the third hollow chamber of the holding portion. It is a graph.

[Explanation of symbols]

In the figure, 1 is a top plate (mounting board), 2 is a leg, 20 is a second hollow chamber, 3 is a base, 33 is a third hollow chamber, 5 is a hanging member, 50
Indicates a first hollow chamber, and E indicates cast iron powder (powder granules).

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Claims (4)

(57) [Claims] 1. A speaker stand comprising: a mounting board on which a speaker is mounted; legs supporting the mounting board; and a suspension member suspended from the mounting board, the suspension member comprising: 1. A speaker stand comprising a hollow chamber, and a large number of powder particles having cast iron containing graphite as a main component is charged in the hollow chamber. 2. A speaker stand comprising a mounting board on which a speaker is mounted, legs for supporting the mounting board, and a suspending member suspended from the mounting board, the suspending member comprising: The first hollow chamber is provided, the leg is provided with a second hollow chamber, and the first hollow chamber and the second hollow chamber are charged with a large number of powder particles containing cast iron containing graphite as a main component. A speaker stand that is characterized by being. 3. A mounting board on which a speaker is mounted, legs for supporting the mounting board, a suspension member suspended from the mounting board, and a base for holding the legs and facing a stand installation surface. And a suspension member having a first hollow chamber, the leg having a second hollow chamber, the base having a third hollow chamber, the first hollow chamber, the first hollow chamber, Two
A loudspeaker stand, characterized in that a large number of powder particles having a main component of cast iron containing graphite are charged in the hollow chamber and the third hollow chamber, respectively. 4. The speaker stand according to claim 1, wherein the speaker stand is provided with a pointed tip end having a pointed tip, and is held on a stand installation surface via the pointed tip end.