JPH0153840B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a speaker stand having a novel configuration and a method for manufacturing the same.

In a floor-type speaker system, etc. that has a relatively large speaker box, if the speaker box is placed directly on the floor, the sound waves that reach the listener directly from the speaker and the sound waves that are reflected from the floor and reach the listener will be mutually affected. It is known that interference increases or decreases the sound pressure at a listening position in a specific frequency band, impairing the sense of hearing.

Furthermore, the box vibrates due to the vibration of the speaker frame and the air vibration inside the box, which propagates to the floor surface and leaks particularly downstairs, causing noise pollution.

Therefore, such a speaker box is normally placed at a certain distance from the floor with a speaker stand interposed between it and the floor.

Also, instead of using a speaker box, a single speaker such as a horn squawker is often placed on the top of the speaker box, but in this case as well, the speaker is used to hold the horn squawker and suppress mutual propagation of vibrations between the two. A stand is often used.

Therefore, such a speaker stand is required to have sufficient rigidity to support the box or speaker, and to have a large weight and internal loss for the purpose of blocking vibration.

Conventionally, most of these speaker stands have been made by combining wooden boards or concrete blocks, but the former has low internal loss and is light in weight, so it does not have good vibration isolation characteristics. Concrete blocks also do not have the above-mentioned characteristics because their internal loss is small.

Therefore, in the past, it has been common practice to use a separate acoustic insulator in addition to the stand in order to improve vibration isolation characteristics.

Therefore, one object of the present invention is to provide a speaker stand with excellent vibration isolation characteristics, and another object is to provide the speaker stand at a low cost.

That is, the present invention provides a speaker stand made of a thermoplastic resin sheet with a large internal loss or a thermoplastic resin sheet mixed with a filler and having a space between an inner wall and an outer wall, and a speaker in which the hollow part is filled with a filler. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The structure of a speaker stand, in which the inside formed by the inner wall is filled with a filler material, and its manufacturing method will be described in detail below along with examples of the manufacturing method thereof.

FIG. 1 shows a molding die used in the manufacturing method of the present invention, in which 1a and 1b are polypropylene sheets (1.5 mm thick) constituting the speaker stand, and 2 is a mold for heating the polypropylene sheets 1a and 1b. A heater, preferably a far-infrared heater.

3 is a convex portion 3a having a curved surface portion 3b at the tip;
A flat portion 3c that is a horizontal extension of the base of the convex portion 3a.
4 is a convex mold consisting of a concave part 4a which is larger in size than the convex part of the convex mold 3 and has a similar shape, and the concave part 4.
This is a concave mold consisting of a flat part 4c that extends horizontally from the open end of a.

Then, small holes 3d and 4d are bored in the respective surfaces of the uneven molds 3 and 4, and the small holes 3
d and 4d are connected to a vacuum pump (not shown), preferably a vacuum pump with a buffer, through the respective molds.

Furthermore, the pins 5 provided in the convex mold 3 are for punching through holes in the polypropylene sheet 1a as will be described later, and have a built-in heating device 5a. A conduction hole 5b is provided which is closed in the protruding state and opened when the pin 5 is retracted to communicate with the outside air.

Next, the method for manufacturing the speaker stand of the present invention using the molding apparatus will be described. First, the heater 2
The two polypropylene sheets 1a and 1b are heated to 160°C to 170°C, respectively.

Then, the polypropylene sheets 1a and 1b once soften and sag, and then become tense due to surface tension.

In this state, the heater 2 is removed, and the uneven molds 4 and 3 are moved upward and downward, respectively, to deform the polypropylene sheets 1b and 1a, while being evacuated for 2 to 3 seconds at a vacuum level of 500 to 600 mHg using a vacuum pump. Then, align both molds 4 and 3 (Fig. 2).

At this time, the polypropylene sheet 1a is brought into close contact with the convex mold surface, and the polypropylene sheet 1b is brought into close contact with the concave mold surface.

Then, the portions where the molds 4 and 3 come into contact, that is, the sheets between the flat portions 4c and 3c of the molds 4 and 3 are bonded by thermocompression.

On the other hand, in the remaining portion, the polypropylene sheets 1b, 1a are molded with a space corresponding to the dimensional difference between the concavo-convex portions 4a, 3a of both molds 4, 3 formed therebetween.

Furthermore, after the concavo-convex molds 4 and 3 are fitted together, the pin 5 heated by the heating device 5a is immediately made to protrude, and a through-hole 31 is bored in the polypropylene sheet 1a (a third
Figure 3-a), then move the pin 5 back (Figure 3-b).
figure).

Then, the conduction hole 5b is opened and the space between the polypropylene sheets 1a and 1b communicates with the outside air through the through hole 31, the heated air in the space is released, and the next time the sheet is cooled, the outside air is introduced. This maintains the pressure balance between the space and the outside air, and prevents the polypropylene sheet from deforming due to pressure changes in the space during and after molding.

Further, compressed air can be allowed to flow into the space through the through holes 31 during molding to improve the close contact of each polypropylene sheet to the mold surface.

After the sheet has cooled, it is taken out from the mold and a part or all of the portions that are thermocompressed in contact with the flat portions 3c, 4c are cut out to obtain the speaker stand shown in FIG. 4.

In the speaker stand obtained by such a manufacturing method, the polypropylene sheet 1a covers the inner wall and 1
Since b has an integrated double wall structure that constitutes the outer wall, its rigidity is extremely high, and since the internal loss of the material itself is large, it has extremely good vibration isolation characteristics, and the vibration of the speaker box placed on it is extremely high. It is possible to suppress the propagation of water to the floor surface.

Further, although the speaker stand has an opening 42 on the rear surface, the rigidity can be further increased by attaching a rear plate 41 obtained by a similar manufacturing method or a plate-shaped body made of another material to the opening 42 by appropriate means. can be increased.

Further, according to the manufacturing method of the present invention, the manufacturing method can be easily manufactured in an extremely short period of time, making it suitable for mass production and having the advantage of low manufacturing costs.

In the above examples, a polypropylene sheet was used as an example, but other materials that can be produced by the production method of the present invention and that can achieve the desired purpose include copolymers mainly composed of polypropylene, polyethylene,
Thermoplastic resins such as copolymers mainly composed of polyethylene, acrylic styrene, polystyrene, and vinyl chloride, and fillers such as SiC, TiO, carbon graphite, glass, mica, talc, and calcium carbonate, etc. Inorganic fibers or inorganic powders, such as organic powders such as wood flour, crystallized cellulose, and natural cellulose, or mixtures of appropriate mixtures of the above-mentioned inorganic powders, inorganic fibers, and organic powders can be used; Each of the sheets may be selected from a different material selected from those listed above.

Further, as shown in FIG. 5, the effect of the speaker stand of the present invention can be further improved by filling the space between the inner wall 1a and the outer wall 1b with a filling material 51 according to the purpose through the through hole 31. .

For example, materials with relatively large internal losses are required to provide internal loss, such as foams such as urethane foam, coal tar, pitch, mixtures of ferrite and polyester, mixtures of crystallized nylon and iron powder, epoxy and organic clay, Suitable materials include silicone resin (preferably room-temperature curing type) and mixtures of balloons such as shirasu balloons and carbon balloons with polyester.As materials for increasing weight (that is, increasing density), for example, coal tar, pitch, etc. Mixtures with inorganic materials such as sand, cement, sludge and sludge (organic fibres) with coal tar or pitch are suitable; for increasing stiffness most of the aforementioned materials have achieved their purpose.

In this manner, by filling the space with the filler material, it was possible to increase the internal loss, increase the weight, and increase the rigidity, and furthermore, it was possible to improve the vibration isolation characteristics.

Furthermore, as shown in FIG. 6, the speaker stand of the present invention improves vibration isolation characteristics by filling the internal space formed by the space and the inner wall with different types of fillers 61 and 62 selected from the materials described above. You can force it.

For example, by filling the space with a material with a large internal loss, such as foam such as foamed urethane, to mainly add internal loss, and by filling the internal space with cement, etc., mainly to add weight and stiffness, it is possible to Due to the synergistic effect, a speaker stand with even better vibration isolation characteristics can be obtained.

Alternatively, the filling material may be selected reversely, and a material that imparts rigidity and weight to the space and a material that imparts internal loss to the internal space may be filled.

Furthermore, according to the manufacturing method of the present invention, it is possible to manufacture a speaker stand not only in the shape described in the embodiments but also in a relatively complicated shape, so that the commercial value can be increased.

Furthermore, although the concave and convex molds were similar in shape to each other in this example, the shape of the convex mold is not limited to being similar to that of the concave mold. All you have to do is decide on the shape.

As explained above, the present invention is made of a thermoplastic resin sheet or a mixture sheet of the thermoplastic resin mixed with a filler, the outer wall and the inner wall are integrally formed, and there is a space between the outer wall and the inner wall. A speaker stand, a speaker stand in which the space is filled with a filler, a speaker stand in which the internal space formed by the space and an inner wall is filled with a filler, and a method for manufacturing the same, as described above. A speaker stand with excellent vibration isolation characteristics and an arbitrary shape can be easily mass-produced, and the manufacturing cost and material cost are low, so a speaker stand with good characteristics can be provided at a low price. It is.

Although the above description has been made regarding a speaker box stand, it goes without saying that the present invention can also be applied to a speaker stand for a speaker unit such as a horn squawker.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional view of a mold device used in the method of manufacturing a speaker stand of the present invention, Fig. 2 is a cross-sectional view of the same molded state, and Figs. 3-a and 3-b are enlarged pin portions of the device. FIG. 4 is a partially cutaway perspective view of the speaker stand of the present invention, and FIGS. 5 and 6 are cross-sectional views of the speaker stand of the present invention.

Claims (1)

[Claims] 1. An inner wall and an outer wall made of a thermoplastic resin sheet or a mixture sheet of a thermoplastic resin mixed with a filler are integrally formed, and a space is provided between the inner wall and the outer wall. Speaker stand. 2. An inner wall and an outer wall made of a thermoplastic resin sheet or a mixture sheet of a thermoplastic resin and a filler are integrally formed, and the space formed between the inner wall and the outer wall is filled with a filler. Speaker stand. 3 An inner wall and an outer wall made of a thermoplastic resin sheet or a mixture sheet of a thermoplastic resin mixed with a filler are integrally formed, and the space formed between the inner wall and the outer wall is filled with a filler, and the inner wall A speaker stand characterized in that an internal space formed by the above-mentioned filling material is filled with a filling material different from the above-mentioned filling material. 4 At least a heater and a concave-convex mold with a small hole for vacuuming, the inner diameter of the concave mold being larger than the outer diameter of the convex mold, and a pin with a heating device for drilling the through-hole. Using a vacuum forming mold equipped with a vacuum forming mold, two sheets of thermoplastic resin or a thermoplastic resin sheet mixed with filler, which are clamped at both edges so as to be spaced apart from each other, are heated with a heater to soften them. , moving the concave mold or the convex mold in opposite directions to deform the sheet, and inserting the convex mold into the concave mold while bringing the sheet into close contact with the surface of the concave and convex molds by vacuuming,
The edges and necessary parts of the sheet are bonded together by thermocompression, and small holes are made at appropriate locations on one of the sheets using the pins. After the formed sheet has cooled, it is taken out from the mold and the two sheets are A method for manufacturing a speaker stand, characterized by obtaining an integrated speaker stand in which an outer wall and an inner wall are formed by sheets and a space is provided between them.