U.S. patent application number 10/278986 was filed with the patent office on 2003-02-27 for apparatus and method of molding composite foam molding element and composite foam molding element obtained by the same.
This patent application is currently assigned to Daisen Industry Co., Ltd.. Invention is credited to Ida, Kiyotaka, Nohara, Iwao, Yoshimura, Shigeki.
Application Number | 20030039800 10/278986 |
Document ID | / |
Family ID | 27342203 |
Filed Date | 2003-02-27 |
United States Patent
Application |
20030039800 |
Kind Code |
A1 |
Nohara, Iwao ; et
al. |
February 27, 2003 |
Apparatus and method of molding composite foam molding element and
composite foam molding element obtained by the same
Abstract
A top side member 4 is attached to the side of one die 2 of a
cavity 6 between a pair of dies 2 and 3, and a back side member 5
is attached to the side of the other die 3. A charge space is
provided between these top and back side members 4 and 5. Raw
material beads each made of a foam resin are supplied between the
charge space, air is discharged from a plurality of work piece
nozzles provided at the side of the die 3, and raw material beads
are charged. At this time, air discharging is started from a work
piece nozzle a41 set at the most distant position from a charger 61
for supplying raw material beads. Air is charged while the air is
discharged sequentially up to the work piece nozzle a21 set at the
most proximal position as the raw material beads are charged. Then,
the raw material beads are heated to be foamed and fused, and the
top and back side members 4 and 5 are integrated with each other
via the foam member 8.
Inventors: |
Nohara, Iwao;
(Nakatugawa-City, JP) ; Yoshimura, Shigeki;
(Ena-gun, JP) ; Ida, Kiyotaka; (Nakatugawa-City,
JP) |
Correspondence
Address: |
PARKHURST & WENDEL, L.L.P.
1421 PRINCE STREET
SUITE 210
ALEXANDRIA
VA
22314-2805
US
|
Assignee: |
Daisen Industry Co., Ltd.
Ageo-City
JP
|
Family ID: |
27342203 |
Appl. No.: |
10/278986 |
Filed: |
October 24, 2002 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10278986 |
Oct 24, 2002 |
|
|
|
09761657 |
Jan 18, 2001 |
|
|
|
Current U.S.
Class: |
428/71 ;
264/46.5; 425/123; 425/127; 425/4R |
Current CPC
Class: |
B29C 44/14 20130101;
Y10T 428/24504 20150115; B29C 44/385 20130101; Y10T 428/233
20150115; Y10T 428/249953 20150401; B29C 44/1233 20130101; Y10T
428/24298 20150115 |
Class at
Publication: |
428/71 ;
425/4.00R; 425/123; 425/127; 264/46.5 |
International
Class: |
B29C 044/12; B32B
003/00 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 1, 2000 |
JP |
2000-24123 |
Jul 3, 2000 |
JP |
2000-200898 |
Dec 19, 2000 |
JP |
2000-385265 |
Claims
What is claimed is:
1. An apparatus of molding a composite foam molding element for
integrating a top side member and a back side member with each
other via a foam member and molding these members, the apparatus
comprising: forming one of a pair of dies accompanying a top side
member, capable of die closing and opening to form a cavity for
foam molding; forming the other die so as to accompany a back side
member; arranging a charger for supplying raw material beads made
of a foam resin at a die at the side of the back side member;
disposing a plurality of work piece nozzles whose openings are
opened at the cavity; and dividing these work piece nozzles into a
plurality of groups, each of which being connected to a work piece
supply device.
2. An apparatus of molding a composite foam molding element as
claimed in claim 1, wherein said work piece nozzles are connected
to a work piece controller, the nozzles being capable of supplying
one or more kinds of work pieces such as exhaust air, heating
steam, pressurization air, vacuum, cooling water or drain.
3. A method of molding a composite foam molding element comprising:
attaching a top side member to one die side of a cavity between a
pair of dies capable of die closing and opening to form a cavity
for foam molding and a back side member to the other die side;
providing a charging space between these top and back side members;
supplying raw material beads made of a foam resin to this charging
space; discharging air from a plurality of work piece nozzles
provided at the side of the die having the back side member
disposed; starting air discharging from a work piece nozzle set at
the most distant position from a charger for supplying raw material
beads when the raw material beads are supplied; charging the raw
material beads in accordance with the charging process of
sequentially performing discharging up to a work piece nozzle set
at the most proximal position as the raw material beads are
charged; and heating these charged raw material beads to cause
foaming and fusion to integrate the top side member and the back
side member with each other via the foam member.
4. A method of molding a composite foam molding element as claimed
in claim 3, wherein any of said top side member, back side member,
and raw material beads is made of a same resin.
5. A method of molding a composite foam molding element as claimed
in claim 3 or claim 4, wherein, in said charging process, a supply
and charge step of performing air exhaust from a work piece nozzle
while raw material beads are supplied from a charger and a
pressurization and charge step of performing air exhaust from a
work piece nozzle while the supply of raw material beads are
stopped, and the supply of charge air is continued are repeatedly
performed once or plural times.
6. A method of molding a composite foam molding element, wherein,
following the charge process as claimed in claim 3 or claim 5, said
top side member and back side member are integrated with each other
via a foam member in accordance with a heating step of supplying a
heating steam from one of said work piece nozzles, and exhausting
air from the other nozzle so as to heat charge raw material beads;
and a heating step of pressurizing the heating steam from all the
work piece nozzles so as to heat and fuse charge raw material
beads.
7. A method of molding a composite foam molding element as claimed
in any of claims 3 to 6, wherein, following the heating and fusing
process, cooling water is supplied between a top or back side
member and an interior face of a die, and the die and composite
foam molding element are directly cooled.
8. A composite foam molding element having a top side member and a
back side member integrated with each other via a form member, said
element obtained by a method of molding a composite foam molding
element as claimed in any of claims 3 to 6, wherein the diameter of
a work piece distribution hole provided at a position at which a
nozzle opening is seen during molding, of the back side member
integrated at the side of a die having a work piece nozzle
disposed, is equal to or smaller than 20 mm, and the pitch is set
to be 5 times or more of the diameter.
9. A composite foam molding element as claimed in claim 8, wherein
the thickness is thin relevant to an area, and said element in
thin, different elongated shape has irregularities or curves.
10. A composite foam molding element as claimed in claim 8 or claim
9, wherein a respective one of said work piece distribution holes
provided at said back side member, excluding the work piece
distribution holes disposed along the peripheral rim of the
composite foam molding element is defined in pitches of at least
100 mm at a portion of less than 10 mm in thickness of the foam
member, and said thickness is defined at a portion of 10 mm or more
with pitches of at least 150 mm.
11. A composite foam molding element as claimed in claim 8, wherein
the thickness of a foam member at a portion that is 70% or more of
the surface area of said top side member is equal to or smaller
than 30 mm, and said element is employed as a container.
12. A composite foam molding element as claimed in claim 8, wherein
the thickness of a foam member at a portion that is 70% or more of
the surface area of said top side member is equal to or smaller
than 30 mm, and said element is employed as an exterior heat
insulating member such as air conditioner, air cleaner,
refrigerator or the like or a composite element of home electronics
product such as drain pan member or air cooling duct thereof.
13. A composite foam molding element as claimed in claim 8, wherein
the thickness of a foam member at a site that is 90% or more of the
surface area of said top side member is equal to or smaller than
100 mm, and said element is employed as an architectural interior
material such as ceiling material, wall material, partition wall
face material or floor material.
14. A composite foam molding element as claimed in claim 8, wherein
the thickness of a form member at a site that is 70% or more of the
surface area of said top side member is equal to or smaller than 30
mm, and said element is employed as an interior member used for an
interior portion of a vehicle such as automobile such as door trim,
glove box, trunk room, installation panel, or ceiling.
15. A composite foam molding element as claimed in claim 8, wherein
the thickness of a foam member at a site that is 70% or more of the
surface area of said top side member is equal to or smaller than
150 mm, and said element is employed as a floor member of a vehicle
such as automobile.
16. A composite foam molding element as claimed in claim 8, said
composite molding element having a top side member and a back side
member integrated with each other via a foam member, wherein said
top side member is formed to be expanded, the thickness of a foam
member at its top is equal to or smaller than 500 mm, and the
element is employed as a shock absorption member such as bumper of
a vehicle such as automobile.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to an improved apparatus and
method of molding a composite foam molding element having a top
side member and a back side member integrated with each other via a
foam member and a novel composite foam molding element obtained by
the same.
[0003] 2. Description of the Related Art
[0004] Conventionally, as a method of manufacturing a composite
foam molding element having a top side member and a back side
member integrated with each other via a foam member, there is
adopted a method described in Japanese Patent Application Laid-open
Nos. 4-344227 and 6-210753.
[0005] A general description of a molding apparatus used by this
method will be given with reference to FIG. 8. First, a space 16
for molding a foam member is formed between a bottom face of an
upper die 11 and a top face of a lower die 15. Then, the top face
of the lower die 15 is formed of an air ventilation porous member
18. A skin 17 attached to the surface is pressure-reduced from a
lower discharge space 19, whereby the skin can be adsorbed by and
fixed to the top face of the lower die 15. In addition, the inside
of the upper die 11 is divided into a left steam chamber 11a
comprising a left steam pipe 11c and a right steam chamber 11b
comprising a right steam pipe 11d. A ventilation hole 12a and a raw
material bead supply pipe 13a are disposed at the bottom face of
the left steam chamber 11a. Similarly, a ventilation hole 12b and a
raw material bead supply pipe 13b are disposed at the lower face of
the right steam chamber 11b.
[0006] In a molding method using such apparatus, the skin 17 is
disposed while the skin is adsorbed by a ventilation porous member
18. Next, base material 14 is disposed at the lower face of the
upper die 11 to ensure the upper and lower dies are closed, and a
space 16 for forming a foam member is provided. In this case, at
the base material 14, there are provided through holes 14a 14d, 14a
and 14b that correspond to the ventilation holes 12a and 12b and
openings of the raw material bead supply pipe 13a and 13b,
respectively. Here, raw material beads are charged in the space 16
through the raw material bead supply pipes 13a and 13b while
charging air is supplied. In this case, however, the steam chambers
11a and 11b maintain pressure reduction without supplying a steam,
and discharge the air in the space 16 through the ventilation holes
12a and 12b. In this way, the charging air supplied together with
raw material beads is forcibly discharged, and only the raw
material beads can be left and charged in the space 16.
[0007] However, in this molding apparatus, 12a and 12b are operated
to pressure reduction at the same time. Thus, raw material beads
are hardly charged at the periphery in the space 16. Moreover, in
the case where the thickness of this space 16 is small, and an area
is large, in particular, partial occlusion occurs during charging,
and the raw material beads hardly reach a portion distant from the
through holes 14a and 14b of the raw material bead supply pipes 13a
and 13b. As a result, non-uniform charging unavoidably occurs.
[0008] In addition, as the molding method using this apparatus,
there has been adopted a heating method in which heating steams are
supplied sequentially from the left steam pipe 11c of the upper die
11 to the left steam chamber 11a, and then, to the steam hole 12a,
and the charged raw material beads are heated, and then, is
sequentially supplied from the ventilation hole 12b to the right
steam chamber 11b, and then, to the right steam pipe lid, and is
discharged. However, in such heating method, there occurs a
tendency that the flow of the heating steam in the space 16
short-passes between the closest ventilation holes 12a and 12b.
Thus, in a case shown in FIG. 8, although fusion advances at the
center portion, there occurs a deviation that fusion is delayed at
a portion close to the right and left ends. As a result, there has
been a serious problem that non-uniform quality in gravity,
appearance, and strength of products occurs.
[0009] In addition, when a skin, base material, and a foam member
are discussed from the aspect of material, for example, in a
conventional combination used in a dashboard of an automobile,
vinyl chloride, polypropylene, and urethane are used for the skin,
back side member, and foam member, respectively, and the top and
back materials are integrated in contact with each other. In recent
years, there has been a growing need for causing each part of the
skin, base material, and foam member to be formed of a material
with the same components, making it possible to ensure recycling.
From this point of view, technological development in which an
olefin based elastomer (TPO) is extensively used for a skin, and an
olefin based polypropylene foam (ERP) is extensively used for a
foam member becomes an important task. The foregoing documents
describe that a polypropylene based or polyethylene based sheet, a
filler-containing solid resin, a foam resin bead or the like is
used as an olefin based resin material for skin 17, base material
14, and foam member. However, with this method as well, it has been
extremely difficult to uniformly manufacture a thin, composite foam
molding element in different elongated shape having its
comparatively small thickness, large area, and irregularities and
curves, as is the case with a drain pan member of an air
conditioner or a dashboard of an automobile, for example.
[0010] Further, in the conventional method, ventilation holes 12a
and 12b for pressure reducing or steam supply are disposed with
intervals of 25 mm to 50 mm, and correspondingly, through holes 14c
and 14d are provided at the base material 14. Thus, there has been
problems with higher die processing and assembling costs and lower
strength of a composite foam molding element caused by the lowered
strength of the base material 14.
[0011] Therefore, it is an object of the present invention to
provide a molding apparatus and method for improving the uniformity
of raw material beads charged in a cavity for molding a foam member
in molding technique for integrating the top and back side members
with each other via a foam member and molding these members, and
improving the uniformity of heating and fusion of these charged raw
material beads, the molding apparatus and method capable of
manufacturing a thin, composite molding element in different
elongated shape having its comparatively small thickness, large
area, and irregularities and curves that has been hardly
manufactured in the conventional techniques.
SUMMARY OF THE INVENTION
[0012] The present invention has been made in order to solve the
foregoing problem. According to the present invention, there is
provided an apparatus of molding a composite foam molding element
for integrating a top side member and a back side member with each
other via a foam member and molding these members, the apparatus
comprising: forming one of a pair of dies accompanying a top side
member, capable of die closing and opening to form a cavity for
foam molding; forming the other die so as to accompany a back side
member; arranging a charger for supplying raw material beads made
of a foam resin at a die at the side of the back side member;
disposing a plurality of work piece nozzles whose openings are
opened at the cavity; and dividing these work piece nozzles into a
plurality of groups, each of which being connected to a work piece
supply device.
[0013] In addition, according to the present invention, there is
provided a method of molding a composite foam molding element
comprising: attaching a top side member to one die side of a cavity
between a pair of dies capable of die closing and opening to form a
cavity for foam molding and a back side member to the other die
side; providing a charging space between these top and back side
members; then supplying raw material beads made of a foam resin to
this charging space; and at the same time, discharging the beads
from a plurality of work piece nozzles provided at the side of the
die having the back side member disposed; starting discharging from
a work piece nozzle set at the most distant position from a charger
for supplying raw material beads when the raw material beads are
supplied; charging the raw material beads in accordance with the
charging process of sequentially performing discharging up to a
work piece nozzle set at the most proximal position as the raw
material beads are charged; and heating these charged raw material
beads to cause foaming and fusion to integrate the top side member
and the back side member with each other via the foam member.
[0014] Following the above charging process, the top and back side
members can be integrated with each other via the foam member using
a preliminary heating step of supplying a heating steam from one of
the adjacent work piece nozzles, and then, discharging the steam
from the other nozzle so as to heat the charged raw material
nozzles; and a heating step of causing the heating steam to be
pressed from all the work piece nozzles so as to heat and fuse the
charged raw material beads. Following the heating step, cooling
water is supplied between the top or back side member and an
interior face of a die, and the die and composite foam molding
element are directly cooled, thereby making it possible to increase
a cooling speed.
[0015] The composite foam molding element of the present invention
is obtained by the above molding method. The composite foam molding
element having the top and back side members with each other via
the foam member is characterized in that the diameter of a work
piece through hole provided at a position at which a nozzle opening
is seen during molding, of a back side member arranged at the side
of a side having work piece nozzles disposed, is equal to or
smaller than 20 mm, and the pitch is set to equal to or greater
than five times as long as the diameter.
[0016] According to the present invention, in integral molding of a
composite foam molding element made of the top and back side
members and the foam member that is a core material, the uniformity
when charging or heating and fusing raw material beads is improved,
and a failure such as non-uniform charging or foaming can be
eliminated. In particular, a thin, composite foam molding element
in different elongated shape having its comparatively small
thickness, large surface area, and irregularities and curves can be
manufactured without quality non-uniformity and lowered strength,
making it possible to ensure equipment cost reduction.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] FIG. 1 is a sectional view of a molding die illustrating a
molding apparatus according to the present invention;
[0018] FIG. 2 is a perspective view of essential parts showing a
rear face of a back die of the molding apparatus according to the
present invention;
[0019] FIG. 3 is a view showing a piping system of the molding
apparatus according to the present invention;
[0020] FIG. 4 is an illustrative view showing the steps of the
charging process in the present invention;
[0021] FIG. 5 is a perspective view of essential parts illustrating
a composite foam molding element according to the present
invention;
[0022] FIG. 6 is a sectional view showing a molding die for
implementing a specific cooling method;
[0023] FIG. 7 is a perspective view showing the molding die shown
in FIG. 6; and
[0024] FIG. 8 is a sectional view of a molding die illustrating a
conventional molding method.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0025] Hereinafter, preferred embodiments of the present invention
will be described. In the present embodiment, a composite foam
molding element configuring a drain pan member for air conditioner
is molded. First, a top side member and a back side member each
made of a polystylene based resin are provided. The top side member
configures a surface layer of a finished composite foam molding
element. This molding element is fabricated by publicly known means
to be a sheet material of about 0.3 mm to 1.0 mm in thickness
comprising a predetermined appearance, surface texture,
flexibility, strength or the like. The back side member is a backup
member that burdens mechanical strength of the molding element, and
a plate material of about 1.5 mm to 5.0 mm in thickness is
used.
[0026] The molding apparatus of the present invention molds a
composite foam molding element integrated by charging, heating, and
fusing raw material beads each made of a foam resin in a space
between the top and back side members disposed in a die. As shown
in FIG. 1 and FIG. 2, a foam molding cavity 6 is formed of a pair
of dies 2 and 3 capable of die closing and opening. One die 2
(hereinafter, referred to as a top die) accompanies a top side
member, and the above mentioned top side member 4 is attached to
the interior face of the die. The other die 3 (hereinafter,
referred to as a back die) accompanies a back side member, and the
above mentioned back side member 5 is attached to the interior face
of the die.
[0027] A charger 61 for supplying raw material beads each
consisting of a foam resin is arranged at the rear side of this
back die 3, and a plurality of work piece nozzles a21, a31, a41,
b21, b31, b41, . . . are disposed so that each nozzle opening is
opened at the cavity 6. In addition, these work piece nozzles a21
to b41, . . . each are divided singly or into a plurality of groups
through pipe systems a2, a3, a4, b2, b3, b4, . . . , as shown in
FIG. 3. Each nozzle is connected to a work piece supply device (not
shown) capable of supplying one or more kinds of work pieces such
as exhaust air, heating steam, pressurization air or drain. A raw
material bead through hole 51 and a work piece flow through hole 52
are provided at positions that correspond to the charger 61 and the
openings of a plurality of work piece nozzles a21 of the back side
member 5.
[0028] As shown in FIG. 2, a rear face that corresponds to the full
face of the cavity 6 of the back side 3 is segmented into three
areas, "a", "b", and "c". Mount holes 6a, 6b, and 6c of the charger
61 are provided at these areas, respectively. For example, with
respect to the area "b", one or more work piece nozzles of the
group "b" are disposed in a plurality of columns such as work piece
nozzles 11 in a first column, work piece nozzles 21 to 25 in a
second column, work piece nozzles 31 to 35 in a third column, and
work piece nozzles 41 to 45 in a fourth column. Such arrangement
applies to the areas "a" and "b" as well. Of course, the number of
areas or the number of columns for nozzles in the present
embodiment is provided as a mere example.
[0029] Now, a work piece supply device in the present invention
will be described by referring to a piping system of the molding
apparatus shown in FIG. 3. Work pieces such as exhaust air, heating
steam, pressurization air or drain used for this molding apparatus
are supplied from a piping system in order of main supply valve 7a,
server tank 73a, and individual supply valves 71a, 71b, 71c, and
71d. The supplied work pieces are discharged from a piping system
in order of individual discharge valves 72a, 72b, 72c, and 74d,
server tank 73b, and main discharge valve 7b. This applies to the
groups "a" and "c" as well.
[0030] Exhaust air or drain is discharged by an exhaust pump, a
vacuum pump or a drain pump provided at the discharge side. Heating
steam, pressurization air or the like is supplied from a steam
generator or an air compressor such as boiler provided at the
supply side. In addition, pressure control is performed by each of
the valves on the supply and discharge sides as required. In the
present invention, the main supply valve 7a and the main discharge
valve 7b are connected so that these valves can be arbitrarily
switched to the exhaust pump, vacuum pump or drain pump for air
exhaust or drain; or the steam generator or air compressor such as
boiler for pressurization air.
[0031] In this piping system, divergent pipes of the piping systems
b1, b2, b3 and b4 connecting the individual supply valves 71a, 71b,
71c and 71d to the individual discharge valves 72a, 72b, 72c and
72d are connected to the work piece nozzles of each column.
Therefore, in this embodiment, operations such as pressurization or
pressure reducing as well as opening and closing operation for
supplying work pieces can be controlled in columns relevant to each
work piece nozzle.
[0032] An arrangement of the piping system is not limited thereto.
Arrangements such as disposition of groups, the number of chargers
or work piece nozzles belonging to each group or columns in each
group may be adopted in the most efficient combination, depending
on the shape, material, or molding conditions for the molding
objects. For example, in FIG. 2 and FIG. 3, although work pieces
are controlled in two stages, i.e., in units of groups and columns,
the piping system is further segmented, thereby making it possible
to control work pieces in units of a single work piece nozzle.
[0033] Now, a method of molding a composite foam molding element
using the molding apparatus of the present invention will be
described in detail with reference to FIG. 1 and FIG. 4.
[0034] A first method is characterized by the charging process. A
basic operation is described below. First, as shown in FIG. 1, a
top side member 4 is disposed at the side of a top die 2 of a
cavity 6 between a pair of dies 2 and 3, and a back side member 5
is disposed at the side of a back die 3. Next, a charge space is
provided between these top and back side members 4 and 5. Then, raw
material beads each made of a foam resin is supplied to this charge
space together with charge air. Further, air is exhausted from a
plurality of work piece nozzles a21 to a41 and b21 to b41 provided
at the side of the die 3 having the back side member 5 disposed,
and raw material beads are charged. One of the important features
in this charging process is that, in exhausting operation of the
work piece nozzles, air exhaust is started from a work piece nozzle
(work pieces a41 and b41 in FIG. 1) set at the most distant
position from the nozzle tip end of the charger 61, and air exhaust
is performed sequentially up to a work piece nozzle (work piece
nozzles a21 and b21 in FIG. 1) set at the most proximal position as
raw material beads are charged. A detailed description will be
given by exemplifying a combination between the charger 61 and the
work piece nozzles a21, a31, and a41.
[0035] Step (1): Of the work piece nozzles a21, a31, and a41, the
work piece nozzle a41 that is the most distant from the charger 61
is placed in an exhaust state, and the frontal work piece nozzles
a21 and a31 are turned OFF to stop operation. Then, the raw
material beads carried from a raw material tank (not shown) at a
carrying pressure are supplied to a charge space 63 from the
charger 61 with a charge air 62. In this case, the raw material
beads are accumulated in the vicinity of an end at which the work
piece nozzle a41 of the charge space 63 is positioned.
[0036] Step (2): Next, the supply of the raw material beads is
temporarily stopped, a pressure is applied to the raw material
beads in the vicinity in which the work piece nozzle a41 is
positioned by the supply of the charge air 62, and an additional
pressure for accelerating charge is applied.
[0037] Step (3): The work piece nozzle a31 is turned ON to be
placed in an exhaust state, and the supply of raw material beads is
restarted to continue charging, and the raw material beads are
accumulated in the vicinity in which the work piece nozzle a31 is
positioned.
[0038] Step (4): As in the step (2), an additional pressure is
applied to the raw material beads charged in step (3).
[0039] Step (5): A work piece nozzle a21 is turned ON to be placed
in an exhaust state (at this stage, all the work piece nozzles are
turned ON). In addition, the supply of raw material beads is
restarted to continue charging, and the raw material beads are
accumulated from the work piece nozzle a21 to a position of the
charger 61.
[0040] At each of these steps, with respect to the accumulated raw
material beads, the exhaust of the distant work piece nozzles is
continued. Thus, charging is serially advanced, and the entire
charging density increases.
[0041] The step (6) is a blow back step in which the pressure of
the charge air 62 and the carrying pressure of the raw material
beads are reversed, and the raw material beads in the charger 61
and the carrying pipe are fed back to the raw material tank
side.
[0042] The foregoing description is briefly given by exemplifying a
combination of the charger 61 and the work piece nozzles a21, a31
and a41. Of course, the present invention is applicable to a
variety of individual work piece nozzles in each of the groups "a",
"b", and "c". That is, each of the individual supply valves 71a to
71d and discharge valves 72a to 72d is controlled, charging
operation is performed in units of individual nozzles and in units
of columns each consisting of a plurality of nozzles, whereby the
charging process corresponding to the shape of a desired composite
foam molding element can be adopted. After charging, the charged
raw material beads are heated, foamed, and fused, and then, the top
side member 4 and the back side member 5 are integrated with each
other via the foam member, whereby a composite foam molding element
can be obtained.
[0043] Now, a second method characterized by the heating and fusing
process of the method of molding the composite foam molding element
according to the present invention will be described here.
[0044] This method performs the above mentioned charging process,
followed by the preliminary heating step and the heating step. That
is, the preliminary heating step supplies heating steam from one
work piece nozzle (for example, work piece nozzle a31 in FIG. 1) of
the adjacent work piece nozzles, exhausts air from the other work
piece nozzle (nozzles a21 and a41 in FIG. 1), distributes the
heating steam, and heats the charge raw material beads. In
addition, the heating step pressurizes the heating steam from all
the work piece nozzles (work piece nozzles a21, a31 and a41 in FIG.
1 in the previous example), and heats and fuses the entire charge
raw material beads. Hence, the uniform heating and fusing process
free of temperature non-uniformity can be implemented, and the top
side member and the back side member can be integrated with each
other via the foam member.
[0045] This method is applicable to a piping system shown in FIG.
3. That is, a heating steam is supplied from a main supply valve
7a, a main discharge valve 7b is connected to the exhaust system to
be set so as to remove the waste steam. Each of the supply valve
and discharge valve is controlled for each of the work piece nozzle
groups such as groups "a", "b" and "c", and the heating and fusing
process including the preliminary heating step and the heating step
can be applied in units of individual nozzles or in units of the
foregoing columns.
[0046] With respect to the length of the path of a heating steam
passing through the inside of the charge raw material beads, in the
case of a conventional method, long and short paths coexist, and a
significant dispersion occurs with a heat rate applied to the
charge raw material beads, and the resultant temperature
non-uniformity causes the fusion non-uniformity of the foam molding
element. However, according to the heating and fusing process of
the present invention, the distribution path of the heating steam
communicates between the adjacent work piece nozzles. Therefore a
distance is comparatively short and uniform, and thus, dispersion
becomes small under the heating conditions and the fusion
non-uniformity of the foam molding element is significantly
improved.
[0047] Further, in the preliminary heating step, the distribution
distance of the heating steam is reversed conveniently without
being fixed to a single direction, and further, repeats reversal,
thereby making it possible to further restrict heating
non-uniformity. As a previous stage of the preliminary heating
step, a method for adding the step of supplying a steam at a
temperature equal to or smaller than the fusion temperature to
exhaust the air in the charge space, and then, internally filling
the steam in advance is preferable because the air that is an
obstacle of foaming the raw material beads can be removed, and
uniform heating at the later stage can be effectively performed. In
this case, air may be supplied or exhausted between the work piece
nozzles distant from each other, for example, between the work
piece nozzles a21 to a41.
[0048] The apparatus and method of molding the composite foam
molding element according to the present invention are
characterized by the above mentioned points. The apparatus and
method are used to effectively restrain charging non-uniformity,
heating non-uniformity, and fusion non-uniformity. When any of the
top and back side members and raw material beads used there is made
of a synthetic resin made of the same components, the raw material
beads form a foam molding element in the process of heating and
fusing the raw material beads. At the same time, the entirety can
be integrated by fusion with the top and back side members. Thus,
the molding method and apparatus can be particularly preferred.
[0049] Further, in a structure comprising a conventional chamber,
it has been necessary to dispose a core bent for supplying and
discharging a variety of work pieces at a full face of a die with
pitches of 25 mm to 40 mm. However, in the case of the work piece
nozzles according to the present invention, the foregoing charging
operation or heating and fusing operation is possible. Pitches of
100 mm to 200 mm can be set, and the number of dispositions is
about {fraction (1/10)} of the conventional number of dispositions.
Thus, the die assembling and processing costs can be significantly
reduced, and is advantageous from the aspect of equipment cost.
[0050] Following the above heating and fusing process, a die is
cooled, and a composite foam molding element is removed. In a
general cooling method including blowing cooling water from the
rear face of a die, much time is required for cooling, and cooling
non-uniformity can occur due to a difference in partial heat
capacity of the die. Then, other method to conduct cooling water
between the inner surface of die and the top or back side member as
shown in FIG. 6, for directly cooling the die and the composite
foam molding element is also possible. Thus, as shown in FIG. 6, a
number of water supply and exhaust openings 9 are provided at a
back die 3, water is supplied to a gap 91 between the back side
member 5 and the back die 3 opposed thereto, and the back die 3 and
the composite foam molding element are directly cooled. In this
manner, the cooling efficiency is remarkably improved, the cooling
time can be reduced, and the cooling non-uniformity is eliminated,
thus making it possible to obtain a uniform, composite foam molding
element. As shown in FIG. 7, a number of supply and discharge
openings 9 are divided into a water supply side and a water exhaust
side. The water supply and exhaust valves connected to these
openings are switched for every appropriate time interval to
reverse the water supply and exhaust sides, whereby the flow
direction of cooling water can be reversed. Similarly, the water
supply openings 9 may be disposed at the top die 2.
[0051] Now, a composite foam molding element according to the
present invention will be described with reference to FIG. 5.
[0052] The features of the composite foam molding element according
to the present invention are obtained by any of the foregoing
methods of molding the composite foam molding elements. In the
composite foam molding element having the top and back side members
4 and 5 integrated with each other via the foam material 8, the
diameter of each of the work piece distribution holes 52a and 52b
being present on the plate face of the back side member 5 disposed
at the side of the back die 3 having work piece nozzles (refer to
reference numerals a21, a31 and a41 in FIG. 1) disposed, the holes
being provided at positions at which the nozzle openings are seen
during molding is equal to or smaller than 20 mm in size, and the
pitches F and D are set to be equal to or greater than 5 times as
large as the diameter of the hole. In this manner, in the present
invention, the disposition pitch can be set to be comparatively
greater relevant to the diameter of the work piece distribution
hole. Thus, even if the work piece distribution holes are provided,
the mechanical strength of the back side member 5 is not lowered.
In addition, the composite foam molding element according to the
present invention is small in thickness relevant to a surface area,
and can be formed in thin, different elongated shape having
irregularities or curves. Thus, in particular, this molding element
can be preferably used for composite members of the home
electronics product described later or interior members of a
vehicle such as automobile.
[0053] Further, of the work piece through holes 52a and 52b
provided at the back side member 5, a mutual interval F of the work
piece distribution hole 52a excluding the work piece distribution
hole 52b disposed along the peripheral rim of the composite foam
molding element (corresponding to a portion at which the top side
member 4 and the back side member 5 are directly superimposed with
each other at a terminal end portion 81 of a foam member 8), can be
defined in pitches of at least 100 mm at a portion at which the
thickness E of the foam member 8 is less than 10 mm, and can be
defined in pitches of at least 150 mm at a portion at which the
thickness E is equal to or greater than 10 mm. The diameter of the
work piece distribution hole 52a is generally set to about 10 mm.
In this embodiment, the mutual pitches of the work piece
distribution holes 52a are 10 times or more of the diameter in
size, and thus, there is no danger that the mechanical strength of
the back side member 5 is lowered.
[0054] In addition, the composite foam molding element according to
the present invention is preferably applied in particular to
specific uses when the thickness of the internal foam member is set
under the conditions described below.
[0055] (1) When the molding element is employed as a container, the
thickness of the foam member at a site that is 70% or more of the
surface area of the top side member is set to 30 mm or less.
[0056] (2) When the molding element is employed as an exterior heat
insulating member of an air conditioner, an air cleaner, a
refrigerator or the like or a composite element of a home
electronic product such as drain pan member or air cooling duct
thereof, the thickness of the foam member at a site that is 70% or
more of the surface area of the top side member is set to 30 mm or
less.
[0057] (3) When the molding element is employed as an architectural
interior material such as ceiling material, wall material,
partition wall face material or floor material, the thickness of
the foam member at a site that is 90% or more of the surface area
of the top side member is set to 100 mm or less.
[0058] (4) When the molding element is employed as an interior
member used for an interior portion a vehicle such as automobile,
including as door trim, glove box, trunk room, installation panel
or ceiling, the thickness of the foam member at a site that is 70%
or more of the surface area of the top side member is set to 30 mm
or less.
[0059] (5) When the molding element is used as a floor member of a
vehicle such as automobile, the thickness of the foam member at a
site that is 70% or more of the surface area of the top side member
is set to 150 mm or less.
[0060] (6) When the molding element is used as a shock absorbing
member such as bumper of a vehicle such as automobile, the molding
element is formed in thick blocks when the entire top side member
is expanded in vertical direction relevant to longitudinal
direction, and the thickness of the foam member at a site
corresponding to its top is set to 500 mm or less.
[0061] As has been described above, the composite foam molding
element obtained by the improved molding apparatus and method
according to the present invention is provided at a low cost as a
large sized member being excellent in design properties, elasticity
touch properties, heat insulation properties, sound absorption
properties, strength of board material or production cost, the
member being free of dispersion in quality. In particular, this
material is particularly useful as a composite element of a home
electronics product, an interior member of a vehicle such as
automobile or architectural interior material listed below.
[0062] (1) Composite elements of home electronics product: For
example, exterior heat insulating member of air conditioner, air
cleaner, refrigerator or the like or functional member of internal
drain pan member, air cooling duct member or the like
[0063] (2) Interior member of vehicle such as automobile: For
example, interior members such as door trim, glove box, trunk trim,
and instrument panel. Elongated members such as shock absorption
member. In particular, this use is effective in cost reduction of
large-sized parts because a large area is made available by
integral molding.
[0064] (3) Architectural interior material: For example, excellent
amenity can be provided in the fields of ceiling materials, wall
materials, and floor materials applied in a conventional synthetic
resin product.
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