Note: Descriptions are shown in the official language in which they were submitted.
SYNTHETIC RESIN MOLDING APPARATUS
sAcKGRouND OF THE INVENTION
The present invention relatles to a synthetic resin
molding apparatus for efficiently manufacturing products
molded of synthetic resin.
Generally, a process oE pouring a resin solution
into a molding assembly to produce a synthetic resin molding
comprises, for example, the steps of setting a coveriny
sheet in a mold assembly composed of male and female mold
dies, closing the mold assembly by moving the male and
female mold dies relatively toward each other, pouring a
resin solution into the mold assembly, and opening the mold
assembly in order to remove the molded product.
After the resin solution has been poured into the
mold assembly, it takes a few minutes for the poured resin
solution to be hardened, and this time interval is a time
loss in the entire molding process. Attempts have been made
to increase the rate of production by interconnecting
molding stations for effecting the molding steps with
conveyors and delivering a number of mold assemblies on the
conveyors so that the molding steps can successively be
carried out.
Products molded of synthetic resin include large-
size moldings such as automotive ins-trument panels. Mold
assemblies for molding such large-size products are expen-
2 ~ '7
sive, and the number of such mold assemblies used is limitedso as to lower the cos-t of molded articles. According to
one proposal, two mold assemblies are employed, and these
mold assemblies are alternately shuttled for molding opera-
tion (see Japanese Laid-Open Patent Publication No.
59(1984)-229325). However, -the proposed system has a limi-
tation on the reduction oE the cycle time.
An effort to shorten the time required to carry out
various operations associated with the opening and closing
of the mold assembly is also one of the important factors
necessary to increase the efficiency of molding production.
When an automotive instrument panel, in particular, is to be
molded, an attachment and a duct have to be assembled in the
male mold die in order to fabricate an instrument panel
region where meters are to be housed, and a covering sheet
having an embossed pattern on its surface has to be set in
the female mold die, before the mold assembly is closed.
Since the mating surfaces, i.e., the product forming
surfaces, of the male and female mold dies face each other,
however, the above-mentioned components cannot easily be set
in the mold dies, and hence the production efficiency will
not be increased substantially.
Japanese Laid-Open Patent Publication No. 58-38417
discloses swingable die holders to which upper and lower
mold dies are fixed. With the disclosed arrangement,
however, the upper and lower mold dies supported on the die
-- 2
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:
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2~
holders cannot be tilted through su~ficient angles to allow
easy setting of necessary components. Furthermore, the
ease with which the components are set is not increased sub-
stantially as the upper and lower mold dies are tilted in
the same direction.
Some molded products such as instrument panels have
undercuts. To mold such an article, a slide core is
employed to give an undercut configuration to the molding.
If an undercut were to be formed by a mold die, it would
become difficult to remove the molded product from the mold
assembly depending on the depth of the undercut formed.
Where a mold die having a slide core is moved to
mold a product of synthetic resin, a problem is posed by
various tubes and hoses such as hydraulic hoses connected to
a cylinder which moves the slide core back and forth and
tubes connected to the mold die for supplying and discharg-
ing cooling water. These tubes and hoses make up a complex
system and cannot be serviced well since they are connected
in such a manner to allow the mold die to move
unobstructedly. To avoid such a drawback, the tubing on a
station is connected to the tubing on the mold die through
tube couplings, and these tubings are disconnected from each
other when the mold die is moved.
The tube couplings for connecting the tubings are
mostly in the form of quick-connect-and-disconnect couplings
of the self-sealing type which include check valves. If a
~i5~'7
produc~ is molded of a resin foam or cellular plastic, when
the tubings are disconnected under a gas pressure developed
by the foaming of the resin material, the pressure in the
cylinder for moving the slide core is lowered to retract the
slide core from its original position. As a result, the
undercut formed in the product is shaped with poor accuracy.
If a covering sheet and a resin sheet are to be integrally
joined, the covering sheet tends to be wrinkled, and the
resulting product becomes defective.
Some mold assemblies for molding resin products
such as instrument panels include a female mold die composed
of a number of separate members that are separable from each
other to allow a molded product to be removed easily (see
Japanese Utility Model Registration Publication No. 60-13619
for example). If a unitary inseparable female mold die were
used, the female mold die would be held in too intimate con-
tact with the product which is complex in shape, and it
would be time-consuming to remove the molded product from
the female mold die.
The separable mold die has its own shortcoming when
the mold assembly is closed. More specifically, when the
separable female mold die is put together and the male mold
die and the female mold die are combined to close the mold
assembly, a mechanism for separating and combining the
female mold die may fail to operate, or the female mold die
may not fully be put together due to an error on the part of
: ~
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the operator. Upon such a failure, the male mold die does
not mate with the ~emale mold die smoothly, and the mold
assembly may be damaged or broken.
To se-t a covering sheet in the separable female
mold die, the covering sheet is sometimes attracted under
vacuum to the female mold die so that the covering sheet is
intimately held against the product forming surface of the
female mold die. To the separable members of the female
mold die, there are connected pipes of an evacuating circuit
for attracting the covering sheet under vacuum to the female
mold die. Unless these pipes are carefully arranged with
respect to the female mold die, they are liable to crack,
leaking the air pressure, because the separable female die
members are repeatedly separated and put together. Inasmuch
as the pipes are connected respectively to the separable
female mold die members, the number of parts used of the
mold assembly is large.
SVMMARY OF THE INVENTION
It is a major object of the present invention to
provide a synthetic resin molding apparatus which can
shorten a cycle tima of molding operation, can be operated
with ease, and can effect the steps of molding a product
highly efficiently.
Another object of the present invention is to pro-
vide an apparatus for molding a product of synthetic resin,
comprising a first station including a mechanism for opening
-- 5
~:O~ 4~
and closing a mold assembly, a second station including a
mechanism for pouring a resin solution into the mold assem-
bly which is closed, a third station for hardening the
poured resin solution in the mold assembly, and a feed mech-
anism interconnecting the first, second, and third stations
in a looped configuration, for circulating at least three
mold assemblies through the first, second, and third
stations.
Still another object of the present invention is to
provide the apparatus wherein the mechanism of the first
station comprises a base, a tilt table angularly movably
supported on the base by a support shaft, a vertically mova-
ble ram, and a holder frame angularly movably supported on
the vertically movable ram by a support shaft, each of the
mold assemblies comprising a first mold die supportable on
the tilt table and a second mold die holdable by:the holder
frame.
Yet another object of the present invention is to
provide the apparatus wherein the holder frame and the tilt
table are swingable in opposite directions, respectively,
into working positions.
Yet still another ob;ect of the present invention
is to provide the apparatus wherein the mechanism of the
first station further includes a pinion gear mounted on the
support shaft by which the holder frame is supported, a
drive source mounted on the vertically movable ram, and a
~ ~ ~5~ 7
rack coupled to the drive source and held in mesh with the
pinion gear, whereby the holder ~rame with the second mold
die held thereby can be angularly moved in response to lin-
ear displacement of the rack caused by the drive source
through the pinion gear.
A further ob;ect of the present invention is to
provide the apparatus wherein the holder frame is angularly
movable through at least goo with respect to a horizontal
plane.
A still further object of the present invention is
to provide the apparatus wherein the feed mechanism com-
prises a carriage for feeding each of the mold assemblies
from the first station to the second station, the first mold
die being supportable on the tilt table through the
carriage, the mechanism of the first station further includ-
ing a cylinder for angularly moving the tilt table through
at least 30 with respect to a horizontal plane.
A yet further ob~ect of the present invention is to
provide the apparatus further including a fourth station for
hardening the poured resin solution in the mold assembly.
A still further object of the present invention is
to provide the apparatus wherein the feed mechanism com-
prises self-propelled tractor means for moving the mold
assemblies between the second station and the third station
and between the third station and the first station.
It is also an object of the present invention to
provide an apparatus for molding a product of synthetic
2~ 7
resin, comprising a mold assembly havlng a first mold die
for placing therein a covering sheet of a predetermined
shape, a second mold die combinable with the first mold die
to define a mold cavity therebetween, and means for pouring
a resin foam solution into the mold cavity to form a molding
integral with the covering sheet, the first mold die having
a plurality of slide cores, each of the slide cores compris-
ing a core member for adding an undercut shape to the
molding, a stop for limiting displacement of the core member
toward the mold cavity, an actuator for displacing -the core
member away from the mold cavity, and a resilient member for
resiliently urging the core member toward the mold cavity.
Another object of the present invention is to pro-
vide the apparatus wherein the actuator comprises a cylinder
having a piston rod, the resilient member comprising a coil
spring disposed around the piston rod, the coil spring hav-
ing an end engaging the stop for normally urging the core
member toward the mold cavity.
Still another object of the present invention is to
provide an apparatus for molding a product of synthetic
resin, comprising a mold assembly having a die plate, first
and second mold dies which define a mold cavity
therebetween, the first mold die being mounted on the die
plate, the first mold die comprising a fixed member fixed to
the die plate, at least one movable member mounted on the
die plate and displaceable away from the fixed member, and a
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resillent member for normally urging the movable mem~er
toward the fixed member to put the first mold die together.
Yet another object of the present invention is to
provide the apparatus wherein the f:irst mold die includes at
least two movable members which are displaceable away from
the fixed member in respective direc,tions which are perpen-
dicular to each other.
Still another object of the present invention is to
provide the apparatus wherein the first mold die has a prod-
uct forming surface facing the mold cavity and composed of a
porous material and/or suction holes, the fixed member hav-
ing a cavity defined therein, the movable member having a
cavity defined therein and communicating with the cavity in
the fixed member through a vent hole, further including a
vacuum pump communicating with the cavity in the fixed
member, whereby the vacuum pump and the cavities in the
fixed and movable members ~ointly provide an evacuating cir-
cuit for evacuating the mold cavity.
A still further object of the present invention is
to provide the apparatus wherein the first mold die includes
a seal member interposed between confronting surfaces of the
fixed and movable members.
The above and other objects~ features and advan-
tages of the present invention will become more apparent
from the following description when taken in conjunction
with the accompanying drawings in which preferred embodi-
g
. .
~ 7
ments of the present invention are shown by way of illus-tra-
tive example.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of an automotive
instrument panel to be molded by a synthetic r0sin molding
apparatus according to the present invention;
FIG. 2 is an enlarged cross-sectional view taken
along line II - II of FIG. l;
FIG. 3 is a plan view showing various stations of
the synthetic resin molding apparatus;
FIG. 4 is a vertical cross-sectional view of a mold
assembly of the synthetic resin molding apparatus;
FIG. 5 is an enlarged fragmentary cross-sectional
view showing a slide core of the mold assembly;
FIG. 6 is a side elevational view, partly broken
away, of the first and second stations of the synthetic
resin molding apparatus;
FIG. 7 is a side elevational view of the second and
third stations of the synthetic resin molding apparatus;
FIG. 8 is a side elevational view, partly broken
away, of the first and fourth stations of the synthetic
resin molding apparatus, the view showing closed mold
assemblies;
FIG. 9 is a view similar to FIG. 8, showing the
condition in which one of the mold assemblies is opened;
FIG. 10 is a vertical cross-sectional view of a
mold assembly according to another embodiment of the present
invention; and
-- 10 --
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,
FIG. 11 is a perspective view of a first mold die
of the mold assembly shown in FIG. 10.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIGS. 1 and 2 show an automobile instrument panel
which is one example of a synthetic resin molding produced
by a synthetic resin molding apparatus according to the pre-
sent invention.
AS shown in FIG. 2, the instrument panel, generally
denoted at 10, is in the form of an integral unitary struc-
ture comprising a covering sheet 12 made of synthetic
leather of vinyl chloride or the like and a core 1~ made of
a resin foam or cellular plastic such as hard urethane, the
core 14 being attached to an inner surface of the covering
sheet 12. As shown in FIG. 1, the instrument panel 10
includes various voids or spaces such as an instrument
region 16 in which various meters will be housed, a steering
column region 18 through which a steering column will be
inserted, and a box region 20 for housing an air-
conditioning unit or an audio unit therein. The instrument
panel 10 also has a defroster region 22 in which to define a
plurality of slots for ejecting hot air from a heater that
is installed in a completed automobile. The instrument
panel 10 has undercuts 24 near the defroster region 22.
FIG. 3 shows various stations of a synthetic resin
molding apparatus 10 according to the present invention.
The stations include a first station 32, a second station
-- 11 --
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34, a third station 36, and a fourth station 38. The syn-
thetic resin molding apparatus 30 has at least three ~old
assemblies 40 which can successively be fed through the
first, second, third, and fourth stations 32, 34, 36, 38
that are interconnected in a looped configuration by a feed
mechanism 41. While the mold assemb:Lies 40 are being posi-
tioned in these stations 32, 34, 36, 38, various operations
are effected on the mold assemblies ~LQ.
As shown in FIG. 4, each of the mold assemblies 40
comprises a first mold die (female mold die) 42 having a
concave mating surface or product forming surface, and a
second mold die (male mold die) 44 having a convex mating
surface or product forming surface, the second mold die 44
being fittable in the first mold die 42. The product form-
ing surfaces of the first and second mold dies 42, 44
jointly define a mold cavity 46 which is complementary in
shape to the instrument panel 10 in the illustrated
embodiment.
The first mold die 42 is fixedly mounted on a die
base 48. The first mold die 42 has a plurality of voids or
cavities sO defined therein and communicating with each
other through vent holes, thus making up an evacuating
circuit.
The product forming surface of the first mold die
42 is preferably made of a porous electroformed body having
a countless number of minute holes or interstices. These
- 12 -
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minute inters-tices of the product forming surface serve as
suction holes communica-ting with the cavities 50 for
attracting the covering sheet 12 to the product forming sur-
face of the first mold die ~2 under a vacuum developed in
the cavities 50. The porous electroformed body may be made
by depositing an electrically conductive layer on the sur-
face of a mold die pattern model, holding a layer of parti-
cles against the surface of the electrically conductive
layer, then electrodepositing a metal layer by an
electroforming process thereby to form an electroformed
shell, and extracting the particles from the electroformed
shell. For further details, reference should be made to
Japanese Laid-Open Patent Publication No. 61(1986)-163290.
Instead of employing the porous electroformed body, the mold
cavity 46 and the cavities 50 may be held in communication
with each other by suction holes as shown in FIG. 4. The
first mold die 42 also has temperature regulating pipes 51
for circulating cooling water therethrough to regulate the
temperature of the first mold die 42.
The first mold die 42 also has a number of slide
cores 52 (one shown) for adding an undercut configuration to
a product molded by the mold assembly 40. The slide core 52
is shown in detail in FIG. 5.
As shown ln FIG. 5, each of the slide cores 52
comprises a core member 54 and a cylinder 56 servlng as an
actuator for moving the core member 54 back and forth. The
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core member 54 has a stop 58 on its lower or inner end for
positioning the upper or outer end of the core member 54
when it projects into the mold cavity 46. The stop 58 is
engageable with a step 60a in a hole 60 which is defined in
the first mold die 42 and receives the slide core 52. To
the stop 58, there is joined a stem 62 coupled to a piston
rod 64 of the cylinder 56. The cylinder 56 has on its lower
end a flange 66 by which the cylinder 56 is fixed to the
first mold die 42 by bolts (not shown) threaded through the
flange 66.
The core member 54 is normally urged resiliently in
the direction indicated by the arrow H, i.e., toward the
mold cavity 46, by a coil spring 70 disposed around the stem
62 between the core member 54 and the cylinder 56, so that
the stop 58 is engaged by the step 60a at all times. The
core member 54 can be retracted in the direction indicated
by the arrow L by actuating the cylinder 56.
On a side wall of the first mold die 42, there is
mounted a joint connector (not shown) connected to a hydrau-
lic hose from a hydraulic power unit for supplying working
oil to the cylinder 56 of each of the slide cores 52. The
joint connector has a quick-connect-and-disconnect fitting
of the self-sealing type.
The second mold die 44 comprises a vertically mova-
ble die mold connected to a lifting/lowering means
(described later on). The second mold die 44 has a hole 76
- 14 -
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,
defined in one end thereof and receiving a sprue 78 in which
a head for pouring a solution of a resin foam or cellular
plastic will be fitted. The second mold die ~4 has a plu-
rality of voids or cavities 80 defined therein so that the
second mold die 94 is reduced in weight, and temperature-
regulating pipes 82 for circulating cooling water
therethrough.
Swingable lock arms 8~a through 84d serving as mold
clamping mechanis~s are mounted on opposite side walls of
the second mold die 44. The lock arms 84a through 84d have
hooked lower distal ends engageable wi-th engaging members
86a through 86d, respectively, fixed to the first mold die
42. The lock arms 8~a through 84d are normally urged to
swing in the directions indicated by the arrows by coil
springs 88a through 88d mounted on the upper wall of the
second mold die ~4, thus holding the hooked ends of the lock
arms 84a through 8~d in engagement with the engaging members
86a through 86d.
As shown in FIGS. 3 through 6, the first station 32
includes a base 124 in which a tilt table 125 is supported
for tilting movement as indicated by the arrows A, B. The
tilt table 125 is tiltably supported by a pair of shafts
126a, 126b (FIG. 6). As shown in FIG. 8, a piston rod 127a
of a tilt cylinder 127 is coupled to the tilt table 125.
The tilt table 125 can be tilted ~5 by extending the piston
rod 127a of the tilt cylinder 127 (see FIG. 9).
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One of the mold dies 40 is mounted on the -tilt
table 125 by a carriage 128 of the feed mechanism 41. The
first and second stations 32, 34 are interconnected by a
feed table 129 on which rails 130a, 130b extending from the
first station 32 to the second station 34 are mounted. The
carriage 128 are movable on and along the rails 1~0a, 130b.
A cylinder 132 having a stroke length corresponding to the
distance traversed by the carriage 1:28 is disposed in the
second station 34 and has a piston rod 134 coupled to one
end of the carriage 128. Locator pins 136a, 136b for fit-
ting in holes defined in the bottom of the mold assembly 40
to position the same are mounted in the tilt table 125 at
ends thereof, the locator pins 136a, 136b being movable upw-
ardly from the upper surEace of the tilt table 125. As
indicated by the broken lines in FIG. 9, the locator pins
136a, 136b are moved by respective cylinders associated
therewith. Similar locator pins 138a, 138b are also dis-
posed in the carriage 128.
FIGS. 6 and 8 show a press mechanism 140 disposed
in the first station 32, for closing and opening the mold
assembly 40 on the carriage 128. The press mechanism 140
comprises a fixed plate mounted on the upper ends of support
columns 142a through 142d vertically mounted on the base
124, and a vertically movable ram 146 disposed belo~ the
fixed plate 144. The fixed plate 144 supports hydraulic
cylinders 148a, 148b for vertically moving the ram 146, and
- 16 -
.
~ 3~4~
have respective piston rods 150a, 150b coupled to the ram
146. The ram 146 has a holder frame 152 for holding the
second mold die 4~ of the mold assembly 40 and vertically
displacing the second mold die 44 in unison with the ram
146.
The holder frame 152 is rotatably supported by a
support shaft 154. A pinion gear 156 is mounted on one end
of the support shaft 154 and held in mesh with a rack 158
connected to the piston rod of a cylinder 160 mounted on the
ram 146. When the cylinder 160 is operated, the rack 158 is
vertically linearly moved to rotate the pinion gear 156 for
angularly moving the holder frame 152 through 120 in the
direction indicated by the arrow C (FIG. 9) which is oppo-
site to the direction in which the tilt table 125 is tilted
in the direction indicated by the arrow A. As shown in FIG.
8, a clamp means for clamping the second mold die 44 to the
holder frame 152 comprises a plurality of clamps 162a
through 162d mounted on the lower end of the holder frame
152. The clamps 162a through 162d are actuatable by respec-
tive cylinders to displace respective dogs 163a through 163d
thereof into and out of engagement with a flange on the
upper end of the second mold die 44.
As illustrated in FIG. 3, locator pins 166a, 166b
for engaging the carriage 128 to position the same are
mounted on the upper surface of the base 164 of the second
station 34. As shown in FIGS. 6 and 7, columns 168a, 168b
- 17 -
are vertically mounted on the base 164 and supports thereon
an attachmen-t table 170 on which there ls installed a pump
unit 172 for pouring a resin solution into the mold assembly
40. The pump unit 172 has a pouring head 174 connected to
the distal end of a piston rod 178 oi- a cylinder 176 fixed
to the attachment table 170.
In FIG. 3, the third station ~6 and the fourth sta-
tion 38 carry out substantially the sarne step of hardening a
resin foam solution poured into the mold assemblies 40.
Since the hardening step takes a longer time than the steps
effected in the first and second stations 32, 34, the hard-
ening step is carried out in the two stations, i.e., the
third and fourth stations 36, 38, and the two mold assem-
blies 40 are al~ays positioned respectively in these sta-
tions 36, 38.
Between the third station 36 and the second station
34, the mold assembly 40 is movably placed on rails 1~32a,
182b laid on a feed table 180. The feed mechanism 41 also
includes a self-propelled tractor carriage 184 movable ;
~etween the third station 36 and the second station 34.
More specifically, guide rails 188a, 188b for guiding the
tractor carriage 184 thereon are mounted on a base 186 of
the third station 36 and the feed table 180. The tractor
carriage 184 has a carriage body 194 supporting a motor 196
as a drive source, the motor 196 having a rotatable output
shaft on which there is mounted a pinion 198 (FIG. 7) mesh-
- 18 -
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ing with a rack 200 parallel to the guide rails 188a, 188b.
The carriage body 194 also has a coupling mechanism for cou-
pling the tractor carriage 184 to the mold assembly 40. The
coupling mechanism includes an engaging plate 201 fixed to a
lower portion of the first mold die 42, and a cylinder 204
mounted on the carriage body 194 for moving a pin 202 into
and out of engagement with the engaging plate 201.
The feed mechanism 41 Eurther includes a roller
conveyor 210 for feeding the mold assembly 40 between the
third and fourth stations 36, 38. The roller conveyor 210
includes a plurality of feed rollers 214 spaced at intervals
and operatively interconnected by a chain 216 which is mova-
ble by a motor 212 disposed in the third station 36 at one
end thereof.
The fourth station 38 is similar in construction to
the third station 34. The fourth station 38 includes a base
220 connected to the base 124 o~ the first station 32 by a
feed table 222 on which rails 224, 224b are mounted. The
mold assembly 40 is movable from the fourth station 38 to
the first station 32 along the rails 224a, 224b. In the
fourth station 38, the feed mechanism 41 includes a self-
propelled tractor carriage 226 for hauling the mold assembly
40, the tractor carriage 226 being movable on and along
guide rails 228a, 228b placed on the base 220 and the feed
table 222. I'he tractor carriage 226 can be moved by a
motor-driven pinion meshing with a rack 230 extending paral-
-- 19 --
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2~0~ f~
lel to the guide rails 228a, 228b. The tractor carriage 226is structurally identical to the tractor carriage 184 in the
third station 36. Therefore, those par-ts of the tractor
carriage 2~6 which are identical to those of the tractor
carriage 1~3 are denoted by identical reference numerals,
and will not be described in detail.
As shown in FIG. 8, an operator deck 232 for the
operator to stand on is disposed directly above the fourth
station 38.
The synthetic resin molding apparatus is basically
constructed as described above. Operation and advantages of
the synthetic resin molding apparatus will be described
below.
The molding process of the synthetic resin molding
apparatus will be described in respect to the steps carried
out on a single mold assembly 40 in the first, second,
third, and fourth stations 32, 34, 36, 38, respectively.
As shown in FIG. 9, before the process of molding
the instrument panel 10 is started, the first mold die 42 on
the tilt table 124 is tilted 45~ to the horizontal plane in
the first station 32, and the second mold die 44 is tilted
in the opposite direction to the tilt table 124. Operators
E, F are assigned respectively to the second mold die 44 and
the first mold die 42. The operator E sets various compo-
nents of the instrument panel 10 on the product forming sur-
face of the second mold die 44, whereas the operator F
- 20 -
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.
4~
places the covering sheet 12 of synthetic leather analogous
to real leather on the product forming surface of the first
mold die 42.
In this embodiment, those components of the instru-
ment panel 10 which are set by the operator E include
attachments for meters and ducts for providing housin~
boxes. The instrument panel 10 includes a core materlal of
a urethane foam.
In the first station 32, the f~rst and second mold
dies 42, 44 are tilted for the operators F, E to set the
components efficiently with a comfortable posture. Since
the first and second mold dies 42, 44 are tilted in the
opposite directions to each other, they can be attended by
the respective operators F, E. Therefore, the time required
to effect the preparatory operation in the first station 32
is shortened.
As shown in FIGS. 4 and 5, the core member 54 of
each slide core 52 in the first mold die 42 of the mold
assembly 40 in the first station 32 is urged toward the mold
cavity 46 under the bias of the coil spring 70, with the
stop 58 engaging the step 60a. Therefore, the distal end of
the core member 54 projects into the mold cavity 46. The
cover sheet 12 is placed on the product forming surface of
the first mold,die 42, and the cavities 50 in the first mold
die 42 are evacuated to attract the cover sheet 12 into
close contact with the first mold die 42, with undercuts 24
formed in the cover sheet 12 by the core members 54.
- 21 -
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2C305~4~
Thereafter, the piston rod 127a of the cylinder 127
is retracted to turn the tilt table 125 in the direction
indicated by the arrow B until the first mold die 42 lies
horizontally. The rack 158 coupled to the cylinder 1~0 is
lifted by the cylinder 160 to turn the second mold die 4~
held by the holder frame 152 through 120 in the direction
indicated by the arrow D until the second mold die 44
assumes a horizontal position.
Then, the ram 146 is lowered to bring the second
mold die 44 into mating engagement with the first mold die
42 by extending the piston rods 150a, 150b of the cylinders
148a, 148b. AS a result, the mold assembly is closed as
shown in FIG. 8. Therefore, the dogs 163a through 163d of
the clamps 162a through 162d are released from the flange of
the second mold die 44, thereby disconnecting the second
mold die 44 from the holder frame 15~. The locator pins
136a, 136b are pulled out of the bottom of the first mold
die 42, and the locator pins 138a, 138b on the carriage 128
engage intG the bottom of the first mold die 42. The car-
riage 128 now can ~eed the mold assembly 40 out of the first
station 32.
The carriage 128 is then transferred from the first
station 32 into the second station 34. More specifically,
as shown in FIGS. 3 and 6, the piston rod 134 of the cylin-
der 132 in the second station 34 is retracted into the cyl-
inder 132 to cause the carriage 128 coupled to the piston
- 22 -
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2~5~ 4~
rod 134 and carrying the mold assembly 40 to move along the
rails 130a, 130b to the second station 34. The mold assem-
bly 40 then stops in the second station 34, after which the
locator pins 166a, 166b on the base 164 latch the bottom of
the first mold die 42 thereby to position the mold assembly
40.
Then, the pump unit 172 shown in FIG. 6 is operated
to pour a solution of a resin foam or cellular plastic such
as a hard urethane foam into the mold assembly 40. More
specifically, the pouring head 174 is lowered into the sprue
78 of the second mold die 44 by the cylinder 176, after
which the resin foam solution is poured into the mold cavity
46 defined in the mold assembly 40. The resin solution is
mixed in the mold cavity 46 and foamed, thus developing a
gas pressure in the mold cavity 46. However, since the core
members 54 of the slide cores 52 in the first mold die 4~
are resiliently biased by the coil springs 70, the core mem-
bers 5~ are resistant to the gas pressure and stay firmly
positioned against accidental displacement.
After the resin foam solution has been poured, the
piston rod 178,of the cylinder 176 is retracted upwardly to
elevate the pouring head 174. Then, the mold assembly 40 is
moved from the second station 34 to the third station 36.
At this time, the tractor carriage 184 of the feed mechanism
41 feeds the mold assembly 40 to the third station 36 as
follows: First, the locator pins 166a, 166b disengage from
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.:: :: .
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the bottom of the first mold die 42 in the second station
34, thereby releasing the mold assembly 40 into readiness
for movement. Then, as shown in FIG. 7, the the motor 196
is energized to rotate the pinion 198 in mesh with the rack
200 for thereby moving the tractor carriage 128 from the
two-dot-and-dash-line position to the solid-line position.
After the tractor carriage 184 has stopped in the solid-line
posltion, the cylinder 204 is operatled to cause the pin 202
to engage the engaging plate 201 on the mold assembly 40.
The motor 196 is then reversed to move back the tractor car-
riage 184 for pulling the mold assembly 40 to the third sta-
tion 36. Thereafter, the resin foam solution is hardened in
the mold assembly 40 in the third station 36. After the
mold station 40 has moved to the third station 36, the car-
riage 128 iS moved back to the first station 32 by the cyl-
inder 132.
The roller conveyor 210 is actuated to deliver the
mold assembly 40 from the third station 36 to the fourth
station 38. More specifically, the motor 212 of the roller
conveyor 210 iS energized to rotate the feed rollers 214
through the chain 216 for thus moving the mold assembly 40
on the feed rollers 214 toward the fourth station 38. The
resin foam solution in the mold assembly 40 is also hardened
in the fourth station 38.
The tractor carriage 226 for feeding the mold
assembly 40 from the fourth station 38 to the first station
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32 operates in exac-tly the same manner as the tra~tor car-
riage 184. Therefore, the operation of the tractor carriage
226 will not be described in detail. with the resin foam
solution hardened in the third and fourth stations 36, 38,
the mold assembly 40 returns to the first station 32, in
which the mold assembly 40 is opened and the molded instru-
ment panel lo is taken out of the mold assembly 40O
More specifically, when the mold assembly 40
arrives at the first station 32, the locator pins 136a, 136b
of the tilt table 125 latch the bottom of the first mold die
42. As a consequence, the mold assembly 40 is positioned
with respect to the tilt table 125, and will be prevented
from being displaced when the tilt table 125 is subsequently
tilted. In order to operate the slide cores 52 in the first
mold die 42, the hydraulic hose from the non-illustrated
hydraulic power unit is joined to the joint connector (not
shown) on the side panel of the mold assembly ~0. Then, the
cylinders 56 of the slide cores 52 are supplied with working
oil from the hydraulic power unit to retract the core mem-
bers 54 in the direction indicated by the arrow L in FIG. 5.
The ram 146 is lowered by the hydraulic cylinders
148a, 148b of the press mechanism 140 until the holder frame
152 engages the second mold die-44. The dogs 163a through
163d of the clamps 162a through 162d are moved into engage-
ment with the flange of the second mold die 44. After the
holder frame 152 and the second mold die 44 have been con-
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5~7
nected to each other, the hydraulic cylinders 148a, 148b are
actuated to lift the ram 146. AS shown in FIG. 9, the cyl-
inder 160 is operated to lower the rack 158 to rotate the
pinion gear 156 to turn the second mold die 44 about the
support shaf-t 154 through 120 in the direction indicated by
the arrow C.
At the same time, the piston rod 127a of ~he cylin-
der 127 is extended to tilt the tilt table 125 and hence the
first mold die 42 about ~he support shafts 126a, 126b
through 45 in the direction indicated by the arrow A that
is opposite to the direction in which the second mold die 44
is tilted.
After the first and second mold dies 42, 44 are
tilted away from each other, the operators F, E effect vari-
ous operations associated with the removal of the molded
instrument panel 10. Since the core members 54 are
retracted from the product molding surface of the first mold
die 42, the instrument panel 10 can easi.ly be removed.
Instrument panels 10 are successively molded while
the three mold assemblies 40 are being successively circu-
lated through the first, second, third, and fourth stations
32, 34, 36, 38. When the mold assemblies 40 are moved, the
hydraulic hose from the hydraulic power unit is disconnected
from the joint connector. Therefore, the hydraulic hose
does not present any obstacle to the movement of the mold
assemblies 40, and the hydraulic drive sy~tem combined with
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the hydraulic po~er unit can be maintained and serviced with
ease.
In actual operation, the three mold assemblies 40
in the synthetic resin molding apparatus 30 are positioned
respectively in the first station 32, the third station 36,
and the fourth station 38. The molding steps are succes-
sively carried out while moving the mold assemblies 30 suc-
cessively through the stations. More specifically, the mold
assembly 40 which is closed in the first station 32 is fed
to the second station 34 by the carriage 128, and supplied
with a resin foam solution in the second station 34. Since
the first station 32 is emptied by the departure of the mold
assembly 40, the mold assembly 40 which has been in the
fourth station 38 is dellvered to the first station 32 by
the tractor carriage 226. The mold assembly 40 which has
stayed in the third station 36 is fed to the emptied fourth
station 38 by the roller conveyor 210. After the resin foam
solution has been poured into the mold assembly 40 in the
second station 34, the mold assembly 40 is moved from the
second station 34 to the third station 36 by the tractor
assembly 184. Accordingly, the molding process is effi- :
ciently carried without producing an undesirable idle time
with respect to the three mold assemblies 40.
FIGS. 10 and 11 show a mold assembly 300 according
to another embodiment of the present inventio~. Those com-
ponents of the mold assembly 300 which are identical to
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.~
those of the mold assembly 40 shown in FIG. 4 are deslgnated
by identical reEerence numerals, and will not be described
in detail.
A first mold die 42 is composed of separate members
for facilitating the removal of a molded product. More
specifically, the first mold die 42 comprises a fixed member
30~, two movable members 304a, 304b disposed forwardly and
rearwardly of the fixed member 302 in the transverse direc-
tion indicated by the arrow X IFI~. 11), and two movable
members 306a, 306b disposed laterally of the fixed member
302 in the longitudinal direction indicated by the arrow Y.
The fixed member 302 is securely mounted on the die plate
48, and has cavities 50 communicating with each other
through vent holes 308. One of the cavities 50 communicates
with a pipe 310 extending from a vacuum pump 312.
The movable members 304a, 304b and the movable mem-
bers 306a, 306b are similarly constructed except that they
are positioned`differently with respect to the fixed member
302. For the sake of brevity, therefore, only the movable
members 304a, 304b will be described, and those parts of the
movable members 306a, 306b which are identical to those of
the movable members 304a, 304b are denoted at identical ref-
erence numerals and will not be described in detail.
The movable members 30~a, 304b are swingably sup-
ported by respective support shafts 314a, 314b. Packings
316a, 316b are intlerposed between confronting surfaces of
.... ~ ~
~ ~ ~5 ~4 ~
the movable members 304a, 304b and the fixed member 302 for
keeping the cavities 50 therein airtight. There~ore, an
evacuating circuit is defined in the fixed member 302 and
the movable members 304a, 304b through the vent holes 308,
rather than pipes or tubes.
Mechanisms for moving the movable members 304a,
304b away from the fixed rnember 302 are disposed laterally
of the movable members 304a, 30~b. ~ore speci~ically, cyl-
inders 318a, 318b swingably mounted on the die plate 48 have
respective piston rods 320a, 320b coupled by pins to outer
sides of the movable members 304a, 304b. As shown in FIG.
11, the paired movable members 304a, 304b are movable away
from the fixed member 302 in the direction indicated by the
arrow Bl, and the paired movable members 306a, 306b are mov-
able away from ths fixed member 302 in the direction indi-
cated by the arrow B2, which is normal to the direction
indicated by the arrow Bl. The movable members 304a, 304b
and the movable members 306a, 306b are normally urged resi-
liently to move toward the fixed member 302 in the direc-
tions indicated by the arrows Al, A2 by springs 322a, 322b,
so that the first mold die 42 is normally put together. In
the illustrated embodiment, the movable members 304a, 304b
are separably disposed transversely one on each side of the
fixed member 302. However, the fixed member 302 and the
movable member 304a may be combined into a fixed member, and
only the movable member 304b may be movable with respect to
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,
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~ ~3 0~ ii LL~L7
the fixed member. Such a modification may also be posslble
with respect to the longitudinally separable movable members
306a, 306b.
Mold clamp cylinders 324a, 324b are disposed on the
upper panel of the upper mold die 44 and have piston rods
326a, 326b, respectively, which are coupled to the respec-
tive lock arms 84a, 84b.
The mold assembly 300 thus constructed operates as
follows: In the following description about the operation
of the mold assembly 300, emphasis is placed on those
actions which are different from those of the mold assembly
40 according to the preceding embodiment.
The movable members 304a, 304b and the movable mem-
bers 306a, 306b are resiliently urged against the fixed mem-
ber 302 under the resiliency of the springs 322a, 322b. The
covering sheet 12 is placed in the first mold die 42 thus
put together, and then attracted under vacuum to the first
mold die by the vacuum pump 312.
Then, the second mold die 44 is lowered into the
first mold die 42, and they are firmly clamped together by
the lock arms 84a, 84b operated by the mold clamp cylinders
324a, 324b.
The mold cavity 46 is filled with a resin foam
solution. After the poured resin foam solution has been
hardened, the mold assembly 300 is opened, and the molded
instrument panel 10 is taken out. At this time, the cylin-
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ders 31~a, 318b are operated to retract the pis-ton rods
320a, 320b to turn the movable members 304a, 304b and the
movable members 306a, 306b about the support shafts 314a,
314b away from the fixed member 302 in the mutually perpen-
dicular directions indicated by the arrows Bl, B2 against
the bias of the springs 322a, 3~2b. As a result, the molded
instrument panel 10 can easily be removed from the first
mold die 42.
With the present invention, as described above, the
process of molding a product of synthetic resin is composed
of three steps which are effected in respective stations.
More specifically, necessary components are set in the mold
assembly, the mold assembly is closed, and a molded product
is removed from the mold assembly in the first station. A
resin foam solution is poured into the mold assembly in the
second station. The poured resin foam solution is hardened
in the third station. Since these steps are effected in the
at least three stations, the cycle time can be reduced by
circulating at least three mold assemblies successively
through the stations. Inasmuch as the time required to
harden the resin foam solution is long, the third station is
followed by a fourth station, and the molded product is
hardened in the third and fourth stations, so that the
entire process can be carried out efficiently.
In the first station, the first and second mold
dies of each mold assembly are tilted away from each other.
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2c~
Accordingly, the necessary components can be set in the
first and second mold dies and the molded product can be
removed by the operators attending the first and second mold
dies, respectively. These operations and others can be per-
formed by the operators at a comforta~le posture.
Conse~uently, the operators can do required work with ease
and highly efficiently.
Moreover, the core memher of each slide core is
resiliently urged toward the mold cavity by the spring.
When the mold assembly is moved, the hydraulic hose for sup-
plying the cylinder which displaces the core member is
disconnected from the mold assembly, and the core member is
prevented from being positionally displaced. Therefore, the
mold assembly can be moved efficiently, and the molded prod-
uct is prevented from becoming defective due to displacement
of the core member. In addition, the hydraulic drive system
for supplying wor~ing oil to the slide core can easily main-
tained and serviced.
In another embodiment of the present invention, the
first mold die of each mold assembly is composed of separa-
ble members, i.e., a fixed member and movable members which
are normally urged resiliently against the fixed member.
This provides a fail-safe function such that when the second
mold die is fitted into the first mold die, the first mold
die is always put together by the resiliently biased movable
members held against the fixed member. Even if any of the
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.
'``.J
mold clamp cylinders or other parts fails, the mold dies as
they are brought together are protected from damage or
breakage. The movable members are separable away from the
fixed member in longitudinal and transverse directions of
the fixed member. Since the movable members are moved away
from the fixed member in such mutually perpendicular
dir~ctions, the molded product can easily be removed. The
cavities in the fixed and movable members of the first mold
die are held in communication with each other, making up an
evacuating circuit for attracting the cover sheet against
the product forming surface of the first mold die under
vacuum. The ~vacuating circuit thus constructed simplifies
the evacuating system, and is free from a failure such as a
vacuum loss which would otherwise result from the breakage
of a pipe. As a consequence, the synthetic resin molding
apparatus can perform molding operation efficiently.
Although certain preferred embodiments have been
shown and described, it should be understood that many
changes and modifications may be made therein without
departing from the scope of the appended claims.
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