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BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the
structure of a cabinet for audio equipment such as a cabinet for speakers, a cabinet for record
players, and a rack for audio equipment. [Description of the Related Art] A conventional cabinet
for audio equipment, for example, a speaker cabinet will be described. In a conventional speaker
cabinet (hereinafter simply referred to as a cabinet): ■ veneer as wood board, particle board etc.
■ aluminum die casting, ■ plastic Is widely used as a material. [Problems to be Solved by the
Invention] The wood board has a small density, a small Young's modulus, and a sufficient sound
insulation property can not be obtained because of high resonance acuity and parasitic vibration
such as box noise. It had the disadvantage that the hearing was seriously impaired. In addition,
such a cabinet requires the troublesome operation of dimensioning a plate material and
assembling it in a box shape, and in particular, in a cabinet for a closed type speaker system,
strict dimensional accuracy is needed from the viewpoint of preventing air leakage. Had a
problem. Also, in a speaker system consisting of a plurality of loudspeakers having high-pitched
loudspeakers, a partition is provided behind the high-pitched loudspeaker in order to prevent the
high-pitched loudspeaker from being affected by the back pressure of the bass loudspeaker. I
needed accuracy. Also, the aluminum die-cast cabinet is currently applied to only a relatively
small cabinet because of high material cost and processing cost, and further, there is a problem
of high resonance sharpness. Furthermore, when the thickness of the plastic cabinet obtained by
injection molding is increased, it is not possible to provide a highly rigid cabinet having a
sufficient thickness to cause shrinkage or secondary foaming during molding. [Means for Solving
the Problems] In the present invention, the inner wall and the outer wall formed of a
thermoplastic resin sheet or a mixture sheet of a thermoplastic resin mixed with a filler are
thermocompression-bonded at an edge portion and a desired portion if necessary. A cabinet for
an audio device, in which locking grooves for lead wires electrically connecting the speaker input
terminals and the input terminals provided on the cabinet outer wall are integrally formed on the
inner wall. EXAMPLES The present invention will be described below along with the
manufacturing method shown in the examples. FIG. 1 shows a molding apparatus for molding a
cabinet according to the present invention, wherein Ia and lb are 1.5 mm thick polypropylene
sheets with their edge portions clamped, 1a is the inner wall of the cabinet, 1b is the outer wall
of the cabinet Form
2 is a heater for heating the polypropylene sheet, preferably a far infrared heater. Denoted at 3 is
a concave mold, and a disc-like projection 3b is formed at the bottom of the mold corresponding
to the hole to which the speaker is to be attached. The reference numeral 4 denotes a convex
mold, the horizontal dimension of which is smaller than the horizontal dimension of the concave
mold 3, and the vertical dimension of the convex mold 4 is a concave metal because the convex
mold 4 is formed. When it is completely inserted into the mold 3, it is between the disc-like
protrusion 3 b of the concave mold 3 and between the upper end face 3 a of the concave mold 3
and the lower surface 4 a of the overhang part of the convex mold 4. In each case, a gap having a
size smaller than the sum (3 dishes) of the thickness of the polypropylene sheet la% lb is formed.
Further, 4b is a convex portion which is formed in the convex mold 4 and forms a groove in
which a lead wire connecting the input terminal of the speaker attached to the cabinet and the
input terminal attached to the outer wall of the cabinet is engaged. Recesses 4b-are formed at
appropriate intervals in the root portion of the portion 4b. Also, although not shown, small holes
for vacuuming are formed at appropriate places of the concave mold 3 and the convex mold 4,
and the small holes are passed through the mold to a vacuum pump (not shown), preferably a
buffered vacuum pump. It is connected. Reference numeral 5 denotes a punching means for
forming small holes in the polypropylene sheet 1a, and the heating device 5b is built in the
punching pin 5a, and the normal state of the pin 5a and the tip of the pin 5a is an overhang of
the convex mold 4 A conduction hole 5c is provided which is closed by the pin 5a in a state of
protruding from the lower surface 4a and released in a state where the pin 5a is moved upward.
Further, the protruding position of the pin 5a is disposed so as to be located in the horizontal gap
between the concave mold 3 and the convex mold 4. Next, when the shaping ¦ molding method
by the said shaping ¦ molding apparatus is described, the polypropylene sheet of 2 sheets 1a and
1b is first heated by the said heater 2 to 160 degreeC-170 degreeC, respectively. Then,
polypropylene sheet 1as1. b is once softened and slackened and then tensioned by surface
tension. In this state, the heater 2 is removed, the concave mold 3 is moved upward, the convex
mold 4 is moved downward, and the polypropylene sheets la and lb are deformed while
simultaneously using a vacuum pump for 5 seconds Align the concave mold 3 and the convex
mold 4. At that time, the polypropylene sheet 1a closely contacts the surface of the convex mold
4 and 1b closely contacts the surface of the concave mold 3 (FIG. 2). At this time, the pins 5
heated by the heating device are moved downward to pierce the through holes 31 (FIG. 3-a) in
the polypropylene sheet 1a, and then the pins 5a are moved upward (FIG. 3-b) ).
When this happens, the two polypropylene sheets 1a and 1b are thermocompression-bonded and
integrated, but the polypropylene sheet of the portion sandwiched between the disk-like
protruding portion 3b and the upper end face 3a of the concave mold 3 As described above, a
space is formed by the difference between the outer diameter of the convex mold 4 and the inner
diameter of the concave mold 3 and the height of the disc-like protrusion. After the mold is
cooled, air flows into the space through the through hole 31 drilled by the pin 5a to balance with
the atmospheric pressure. After the sheet is cooled, it is taken out of the mold, and a part or all of
the thermocompression-bonded part as the speaker mounting part and an unnecessary part are
cut off to obtain a speaker cabinet 41 having an open rear surface as shown in FIG. Then, the
speaker 42 is attached to a predetermined portion, and the open rear portion is sealed by fixing
the plate-like member 43 obtained by the above method or a plate-like member made of another
material such as particle board with screws or adhesives. Type speaker system is obtained. In the
cabinet 41, lead wire 6 locking grooves 7 as shown in FIG. That is, the locking groove 7 has a
groove portion 71 formed by the convex portion 4 b formed in the convex mold 4 and a
projection 72 formed by the four portions formed at the root portion of the convex portion 4 b.
The protrusion 72 clamps the lead wire 6 to hold the lead wire 6 in the groove 71. [Effects of the
Invention] According to the present invention described above, since the polypropylene sheets 1a
and 1b respectively have the double structure integrated by forming the outer wall and the inner
wall, rigidity can be enhanced, and a space is formed. As a result, the sound insulation property is
improved, and the resonance sharpness can be reduced, so that parasitic vibration such as box
noise can be suppressed. Also, the manufacturing cost can be significantly reduced because the
lead wire locking groove can be integrally formed at the time of molding. Other cabinet materials
include thermoplastic resins such as polystyrene, acrylic styrene, polystyrene and vinyl chloride,
and thermoplastic resins such as SiC, tie carbon graphite as filler, inorganic fibers such as glass,
mica, talc and calcium carbonate or Inorganic powder, wood powder, crystallized cellulose, and
organic powder such as natural cellulose or a composite material in which a mixture of the
inorganic fiber, inorganic powder and organic powder is mixed can be used, and the sheets la
and 1b are respectively selected from the above materials Different materials may be selected. If
necessary, a filler can be placed in the space to improve the performance, and for the purpose of
reducing the resonance sharpness as a filler, urethane foam, coal tar, pitch, a mixture of ferrite
and polyester, crystallization Mixtures of nylon and iron powder, epoxy and organoclay, silicone
resin and shirasu balloon, balloon and polyester such as carbon balloon, etc. are suitable, and for
the purpose of increasing weight (apparent increase of specific gravity), coal tar, pitch Mixtures
of these with inorganics such as sand, cement, sera and sludge (organic fibers) and coal tar or
mixtures of pitch are suitable.
Most of the above composites can be employed for the purpose of further enhancing the rigidity.
Brief description of the drawings
1 to 3 are sectional views of a molding apparatus for forming a cabinet according to the present
invention, FIG. 4 is a sectional view of the embodiment of the present invention, and FIG. 5 is a
perspective view of the main parts of lead wire locking grooves. is there.
Patent applicant Onkyo Co., Ltd. No. 4