Note: Descriptions are shown in the official language in which they were submitted.
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Moulding Machine
Field of the invention
The present invention is directed to improvements in or relating to machines
for moulding
articles. The invention is more particularly directed to a moulding machine
which is
adapted to high speed production of moulded articles.
Background of the invention
Whilst the following discussion is primarily directed to moulding machines
which are used
to mould plastic articles, it is to be understood that the same principles
apply to moulding
of other flowable materials such as rubber, aluminium, alloys, ceramics and
food materials.
Traditionally, the moulding of plastic material, whether it be injection
moulding, blow
moulding or by other moulding means, relies upon the use of a mould in which
the article
is produced. The moulds may be made up of a number of parts depending upon the
complexity of the article to be moulded.
Further, conventional moulding machines rely upon two parts of the mould
coming
together to form the desired mould cavity. These are usually supported in a
single
machine.
Consequently, there is an inherent limitation upon the rate of production of
the articles
which is dependent upon the number of individual machines which are in
operation.
It is also known from a number of publications that attempts have been made to
form
mould cavities with moulds mounted on a continuous belt in an effort to
increase the rate
of production of plastic articles. However, these are complex and limited in
their
application to a wide range of flowable materials.
Summary of the invention
According to a first aspect of the invention, there is provided a mould device
comprising:
(a) a frame;
(b) a pair of first mould parts located on the frame at spaced first and
second
moulding stations;
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(c) a pair of mould part carriers located on the frame and moveable relative
to
each other and the first and second moulding stations;
(d) a pair of second mould parts each mounted on one of the mould part
carriers; and
(e) an actuator located between the mould carriers to move the second mould
parts into and out of registry with the first mould parts.
When a first mould part registers with a corresponding second mould part,
either all or part
of a mould is formed. This mould has at least one mould cavity to receive
moulding
material for forming an article. However, it will be understood that the mould
may be
to comprised of more than two parts. Likewise, a mould may comprise a
plurality of mould
cavities fox forming plural articles.
In one embodiment, the mould device may further comprise at least one further
mould part
which registers with respective first and second mould parts to form at least
one moulding
cavity in which articles can be formed.
It will be understood that the pair of first mould parts and/or second mould
parts need not
be identical and that the mould device could therefore be producing different
articles from
each mould. It will further be understood that one of the mould carriers may
carry a blank
as one of the second mould parts and that therefore the mould device could be
used to
produce articles from just one mould.
2o The mould device may comprise one, two, three, four or any number of pairs
of moulds
comprised of first and second mould parts as desired. Therefore, the mould
device may
comprise further pairs of mould parts and mould carriers. Preferably, the
mould device
will comprise one or two pairs of moulds, that is, the mould device will
comprise two or
four moulds.
In another embodiment, the mould device further comprises
(f) a pair of further first mould parts located on the frame at spaced third
and
fourth moulding stations;
(g) a pair of further mould part carriers located on the frame and moveable
relative to each other and the third and fourth moulding stations;
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(h) a pair of further second mould parts each mounted on one of the mould part
carriers; and
(i) a further actuator located between the mould carriers to move the second
mould parts into and out of registry with the first mould parts.
The frame of the mould device is typically rectangular, although other frame
shapes are
envisaged within the scope of the present invention. For example, where there
are two
pairs of moulds, or four moulds, the frame may be in the shape of a cross.
Preferably, the first mould parts are fixed relative to the frame of the mould
device, and the
second mould parts are movable toward and away from the first mould parts.
to The actuator may be any suitable mechanical and/or hydraulic means to
facilitate
movement of the mould carriers relative to one another. For example, movement
may be
effected by hydraulic and/or mechanical means. Other means by which the mould
parts
are moved relative to one another are envisaged within the scope of the
present invention.
For example, the second mould parts may be mechanically coupled to an
intermediate cam
mechanism, whereby on actuation of the cam mechanism, such as by rotation, the
second
mould parts are movable toward or away from their respective first mould parts
as the case
may be. Alternatively, a set of toggles may join the second set of mould parts
so that the
action of a hydraulic device will cause the toggles to move the second mould
parts away
from each other and into registry with the first mould parts. The toggles
would then lock
2o the mould parts into the registered position while the articles were being
formed.
A mould device according to the invention will typically comprise at least one
inlet port
for introduction of moulding material or other substrate for forming an
article. There may
be one inlet port for all the moulds in the mould device where only one
moulding substrate
will be used or there may be more than one inlet port to allow for the use of
different
moulding materials within the single mould device. Preferably, the mould
device is
provided with a separate inlet port for each mould so that different moulding
material/substrate may be used in each mould.
It will be understood by persons skilled in the art that the mould device can
be used in any
orientation - for example upright, upside down, on its side or on its end. For
example, a
3o mould device may be placed on its end so that a robotic arm will have
access to place an
object into the mould about which the article is formed.
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It is important that during the moulding process an effective seal is formed
between
respective moulds which are brought into registry in the case of a mould
comprising first
and second mould parts. This sealing can be achieved by any method known to
those
skilled in the art. Preferably, the sealing is achieved by comprising pressure
means to
apply pressure to the first mould part and/or the second mould part to
maintain the mould
parts together. Preferably, the sealing means is a hydraulic bladder or ram or
mechanical
means.
Following injection or the addition of a substrate for moulding into a mould
such as a gas
in the case of a blow moulding operation, the articles may be subjected to a
period of in-
to mould cooling prior to being delivered from the mould cavities.
Preferably, the second mould parts are adapted to retain the moulded articles
following
separation of the second mould part from the first mould part.
The articles may be removed from the moulds from a cooling station within the
boundaries
of the frame or at a cooling station remote from the frame. The articles may
be removed
from the mould by any suitable means. For example, manually, by a robotic arm,
vacuum
or blown off with a stream of air.
One of the mould parts is arranged to also be movable to a station at which
the articles are
removed from the mould part is spaced from the frame. Typically, when there
are two
moulds each having opposed pairs of mould parts, one part of each mould is
fixed relative
2o to the frame of the mould device, and the other part of each mould is
movable away from
the first mentioned mould parts; and then to the station spaced from the fixed
mould.
Following such an operation the mould parts are brought back into registry for
a new
moulding cycle.
According to another embodiment of the invention, the second mould part is
moveable to a
cooling station remote from the first mould parts. Typically the mould device
could be
fitted with a lifting device capable of extension and retraction to facilitate
movement of the
second mould parts to the station remote from the frame.
Once the mould part reaches the station, the articles could complete their
cooling whilst
still attached to the mould part or the articles could be delivered to a
cooling device located
3o at the cooling stations to receive the formed articles.
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Depending on the articles being formed, the station may further comprise a
cooling device
located at the cooling stations to receive the formed articles. In this
embodiment, the
mould part bearing the formed articles moves to the station and the articles
are delivered to
the cooling means. The cooling device may be connected to the frame. The
cooling
5 device may be removable from the frame. In this arrangement, at least one
set of articles
can be formed by the moulds whilst at least one other set of articles can be
concurrently
cooled on the cooling device during a machine cycle.
The cooling device may be in any suitable form. For example, the cooling
device could be
in the form of a tower with one face or the cooling device could be in the
form of a
rotatable triangular prism with three faces or a barrel. By using a rotatable
multi-faced
cooling device the rate of production can be increased where the cooling time
is longer
than the moulding time. Preferably, the cooling device is adapted to receive
more than one
batch from the mould.
A significant advantage of this preferred aspect of the invention is that
plural sets of
articles can be concurrently formed by the moulds and cooled by the cooling
means,
significantly increasing the output capacity of the machine during a single
cycle.
The cooling devices will typically have a number of cavities corresponding to
the number
of cavities of the mould so as to receive a number of articles equal to the
number formed in
the mould cavities. The cooling device may comprise a vacuum source to
facilitate
transfer of articles from the mould to the cooling device cavities. The vacuum
source may
also facilitate the holding of the articles in the cooling device cavities
during cooling.
Preferably, the cooled articles are discharged from the cooling device by
vacuum, a
mechanical device or by gravity. In one presently preferred embodiment, a
cooling device
is movable relative to the frame of the mould device between a first position
in which the
articles are received by the cooling device and a second position where the
articles are
discharged from the cooling device. The cooling device may be pivotable
relative to the
frame of the mould device so that the cooling device pivots outwardly relative
to the mould
device for discharge of the cooled articles.
According to a second aspect of the invention, there is provided a continuous
moulding
machine comprising:
(a) a continuous moulding pathway; and
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(b) a plurality of mould devices mounted on the moulding pathway, at least one
of the mould devices being as described herein.
A continuous moulding machine according to the invention may be an injection
moulding
machine, a blow moulding machine, or other suitable moulding type.
In another preferred form of the invention, the continuous moulding machine
further
comprises:
(d) cooling devices for receiving an article from the mould for cooling.
In this arrangement the moulds and the cooling devices are separate so that at
least one set
of articles can be formed by the moulds whilst at least one other set of
articles can be
1 o concurrently cooled by the cooling devices during a machine cycle.
The continuous moulding pathway may be manifested in any suitable form.
However,
particularly preferred forms of this pathway are generally circular or partly
circular. The
continuous moulding pathway may be a static platform or a movable platform.
The static
platform may be circular, linear, s-shaped or other format. The moving
platform may be a
moving circular platform or an elongated pathway formed by a conveyor
encircling two or
more spaced wheels and forming a generally elliptical pathway.
A conveyor according to the invention is typically an endless conveyor,
although it will be
appreciated that other conveyor configurations can be utilized in the practice
of the present
invention.
2o Where the moulding pathway is provided by a moving platform, the moulding
material
may be provided at an injection station which the mould devices pass on the
moulding
pathway.
Where the moulding pathway is a static platform, a single ring main supply or
a multiple
ring main supply may be used to supply the moulding material. If the mould
devices have
more than one inlet port, a different supply ring can service each inlet port
so that the one
mould device can produce different articles.
The present invention provides in another separate embodiment a continuous
moulding
machine comprising:
(a) a continuous moulding pathway;
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(b) a plurality of mould devices mounted on the moulding pathway, at least one
of the mould devices as described herein;
(c) each mould device having cooling devices associated therewith for cooling
an article formed in the mould; and
(d) transfer means for transferring an article from the station to the cooling
devices.
The present invention provides in a separate embodiment a continuous injection
moulding
machine comprising:
(a) a continuous moulding pathway;
(b) a plurality of mould devices mounted on the moulding pathway, at least one
of the mould devices as described herein;
(c) an injection station located along the moulding pathway having at least
one
injection nozzle for injecting a predetermined quantity of moulding material
into each mould as the moulds pass the injection station during a moulding
cycle, the injection nozzle being releasably engagable with one of the
moulds and stationary in the moulding pathway direction relative to that
mould when engaging, disengaging and when engaged in that mould; and
(d) a controller for drawing the predetermined quantity of moulding material
from a bulk supply of moulding material and supplying that quantity to the
nozzle.
The controller will typically comprise a computer and associated sensing
and/or
monitoring equipment.
A continuous injection moulding machine according to this embodiment will
typically
comprise a cooling device at a cooling station as described herein associated
with each
mould device.
One significant advantage of the injection station is the lack of relative
movement of the
nozzle with the mould when engaging, disengaging and whilst engaged which
means that
alignment is achieved in a linear direction. Typically, this may be achieved
by having a
number of injection stations disposed about the periphery of a rotary device
(eg a wheel).
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Alternatively, whilst the nozzles may be arranged about the periphery of the
radial device,
each nozzle is connected to a radial arm which also connects to a hub device.
That hub
device is in turn connected to a pressure feed system such as a single
injection cylinder. In
this arrangement each nozzle has a valve, the opening and closing of which is
controlled by
the controller. Consequently, in this arrangement individual injection
cylinders associated
with each of the nozzles is avoided and a relatively simple array of valves
can be used to
deliver moulding material to the moulds.
Preferably, a moulding machine according to the present invention further
comprises a
detector to detect failure of clearing of the moulded article from the mould
so that
to corrective action may be taken to maintain the efficiency of operation of
the machine.
With this arrangement, it is possible to overcome the traditional difficulty
of registry of
portions of the mould when mould portions are mounted on contra rotating
conveyors. By
locating the mould in the device, which is in turn mounted on the moulding
pathway, the
registry and conveying function associated with moulds which have mufti parts
is
separated.
An added benefit of the invention is its potential to be designed so as to
have a relatively
compact size. For example, such machine may take up only marginally more
factory space
than a conventional moulding machine but deliver significant production
improvements.
The present invention provides in a separate embodiment a method for producing
moulded
articles in a production cycle having a continuous moulding pathway, a
plurality of mould
devices mounted on the pathway, at least one of the mould devices as described
herein, the
method comprising the steps o~
(a) forming the mould;
(b) introducing moulding material into a mould for forming an article;
(c) forming the article in the mould in a moulding position; and
(d) separating the mould and recovering the article.
This method of the invention, in a preferred form, comprises the additional
step of:
(e) delivering the article formed by the mould from the moulding position to a
cooling position for cooling the article;
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the arrangement being such that moulding and cooling of separate articles can
occur
concurrently during a production cycle.
The method may further comprise a control step to control a parameter of the
production
cycle. A parameter of the production cycle may comprise control over the
metering of
moulding material to the mould, the rate of cooling of articles in the cooling
position, and
the speed and/or timing of a production cycle and of the steps in the cycle.
Brief description of preferred embodiment
The invention will now be further explained and illustrated by reference to
the
accompanying drawings in which:
o Figure 1 is a perspective view of a mould device according to one embodiment
of the
invention with the mould parts registering in the moulding position;
Figure 2 is a perspective view of the mould device of Figure 1 with the mould
parts
disengaged;
Figure 3 is a side elevation of the mould device of Figure 1 with the second
mould parts at
a cooling station remote from the first mould parts;
Figure 4 is a perspective of the mould device of Figure 1 showing the articles
being
transferred from the second mould parts to a cooling device;
Figure 5 is a perspective view of the mould device of Figure 1 showing the
cooling device
in the article discharge position;
Figure 6 is a perspective view of part of a mould device according to a second
embodiment;
Figure 7 is a perspective view of the mould device of Figure 6 showing the
mould parts
registering together
Figure 8 is a perspective view of the mould device of Figure 6 showing the
cooling
devices;
Figure 9 is a perspective view of a mould device according to a third
embodiment of the
invention;
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Figure 10 is a perspective view of a mould device according to a fourth
embodiment of the
invention;
Figure 11 is a perspective view of a continuous moulding machine according to
one
embodiment of the invention;
5 Figure 12 is a perspective view of a continuous moulding machine according
to a second
embodiment of the invention;
Figure 13 is a schematic of a typical machine cycle according to one
embodiment of the
present invention;
Figure 14 is a side view of an alternative radial injection device; and
to Figure 15 is an end view of the radial injection device of Figure 14.
Figure 1 shows a mould device (20) comprising a frame (21 ) which is
rectangular, a pair of
first mould parts (22, 23) at first and second moulding stations (24, 25), a
pair of mould
part carriers (26, 27), a pair of second mould parts (28, 29) mounted on the
mould part
carriers (26, 27) and an actuator (30). Mould device (20) also has a pair of
cooling devices
(31, 32).
Mould part carriers (26, 27) move relative to each other and the first and
second moulding
stations (24, 25) to bring second mould parts (28, 29) into and out of
registry with first
mould parts (21, 22). The actuator (30) is located between the mould part
carriers (26, 27)
and is connected to the second mould parts (28, 29) to move the second mould
parts (28,
29) into and out of registry with the first mould parts (21, 22).
When the first mould parts (21, 22) and second mould parts (28, 29) are in
registry they
form a plurality of mould cavities to facilitate formation of a corresponding
plurality of
articles following receipt of moulding material through the injection ports
(33, 34).
As can be seen from Figures 1 and 2, the second mould parts (28, 29) are
movable relative
to one another between a moulding position shown in Figure 1 and a disengaged
position
shown in Figure 2 where the mould parts are out of registry by retraction of
second mould
parts (28, 29). Second mould parts (28, 29) are adapted to retain the moulded
articles
following separation of the second mould parts (28, 29) from the first mould
parts (21, 22).
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The actuator (30) is in the form of a cam mechanism mechanically coupled to
the mould
parts (28, 29) to move the second mould parts (28, 29) into registry with the
first mould
parts (21, 22) and holds them there during formation of the articles as shown
in Figure 1.
Cooling devices (31, 32) are located at a cooling station remote from first
mould parts (21,
22) and have a plurality of cavities to receive the formed articles as
illustrated in Figures 3
and 4. Second mould parts (28, 29) are moved to the cooling station remote
from the first
mould parts (21, 22) by transfer means (not shown). The transfer means
comprises a pair
of hydraulically activated axially movable pistons connected to the base of
second mould
parts (28, 29).
to Once the second mould parts (28, 29) have reached the cooling stations
remote from first
mould parts (21, 22), the actuator (30) moves the second mould parts (28, 29)
into registry
with cooling devices (31, 32) so that the formed articles are received into
the cavities of the
cooling devices (31, 32) as shown in Figure 5. A vacuum source (not shown) is
connected
to cooling devices (31, 32)) to assist in withdrawing the formed articles from
the second
mould parts (28, 29) and to hold the formed articles in corresponding cavities
of the
cooling devices (31, 32) so that a moulding cycle can be repeated by
withdrawing second
mould parts (28, 29) from their respective cooling stations and returning them
to the
moulding position shown in Figure 1 to receive fresh moulding material for
forming
another batch of articles while cooling of other articles is taking place in
cooling stations
(31, 32).
By virtue of, amongst other things, pivot connections (36, 37), the cooling
devices (31, 32)
are movable outwardly relative to the frame (21 ) to enable discharge of the
cooled articles
from the cooling stations (31, 32). The cooled articles may be discharged to a
receiving
station such as a hopper (not shown).
In Figure 6, mould device (40) comprises opposed moulds consisting of first
mould parts
(41, 42) and second mould parts (43, 44). First mould parts (41, 42) typically
have 52
mould cavities to form 52 articles. Second mould parts (43, 44) are mounted on
mould
part carriers (45, 46) and are movable relative to one another via toggles
(47), hydraulic
ram (48) and locking toggle (49). Hydraulic bladder (50) provides pressure to
seal the first
3o mould parts (41, 42) and second mould parts (43, 44) together when
registering together as
a mould to form articles.
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Figure 7 shows the first mould parts (41, 42) registering with the second
mould parts (43,
44) due to the action of toggles (47) and locking toggle (49) in its locking
position. Figure
8 shows the locking toggle (49) starting to unlock so that second mould parts
(43, 44) can
move towards each other to disengage from first mould parts (41, 42), in
preparation to
move the formed articles to the cooling stations to deliver them to the
cooling devices (51,
52). Second mould parts (43, 44) are raised to the third position, that is,
the level of the
cooling devices (51, 52) via a hydraulic press (not shown).
Figure 9 shows a mould device ( 100) comprising one pair of first mould parts
( 1 O 1, 102)
and a further pair of first mould parts (103, 104), one pair of second mould
parts (105, 106)
1 o and a further pair of second mould parts ( 107, 108) and actuator ( 109).
Mould device
(100) further comprises cooling devices (110, 111, 112, 113). Frame (114)
holds the
mould parts in a cross-shaped configuration so that there are two pairs of
opposed moulds,
that is, four moulds. Actuator (109) is suitable hydraulic or mechanical
means, for
example there may be a cam in the center which operates the toggles.
Figure 10 shows a mould device ( 150) comprising a frame ( 151 ), first mould
parts ( 152,
153), second mould parts (154, 155) and actuator (156). Mould device (150)
further
comprises cooling devices (157, 158). Cooling devices (157, 158) are
triangular prisms
with three faces available to receive formed articles from second mould parts
(154, 155).
Figure 11 shows a continuous moulding machine (200) comprising mould devices
(201 ) on
2o wheel structure (202) which is a static platform. The mould devices (201 )
have two inlet
ports (203, 204). Inner inlet ports (203) can be connected to the same single
ring main
supply (not shown) as outer inlet ports (204) or inner inlet ports (203) can
have a separate
single ring main supply (not shown). Each single ring main supply is connected
to a
hopper (not shown) containing the moulding material (not shown).
Figure 12 shows a continuous moulding machine (220) comprising continuous
moulding
pathway in the form of an endless conveyor (221 ), and a plurality of mould
devices (222)
mounted on the conveyor (221 ). Endless conveyor (221 ) is driven by drive
means (223) in
the form of a drive wheel. Other conveyor drive means are envisaged within the
scope of
the present invention.
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A pair of rotary injection stations (224, 225) are disposed on either side of
the moulding
pathway (221 ) to provide a source of moulding material to the moulds of mould
devices
(222).
The rotary injection stations (224, 225) comprise a wheel having a plurality
of
circumferentially-disposed injectors (226) providing moulding material from a
bulk feed
supply (not shown) to the injectors (226) for supply of moulding material
through inlet
ports (227) of mould devices (222) as they pass the injection stations (224,
225).
Machine (220) may be supported in any suitable manner such as via support
(228).
Similarly rotor injection stations (224, 225) may be supported by a support
(229) arranged
to to facilitate mounting of the injection stations (224, 225) for rotation.
Other support
arrangements are envisaged within the scope of the present invention.
As the formed articles are cooled, mould devices (222) gradually become
inverted as they
travel along moulding pathway (221 ). By virtue of amongst other things the
pivot
connections (230) of cooling devices (231), the cooling devices (231) are
movable
outwardly relative to the moulding pathway (221 ) to enable discharge of the
cooled
articles. The cooled articles may be discharged to a receiving station such as
a hopper (not
shown).
The injectors (226) have nozzles which are releasably engagable with moulds
(21,22) and
are stationary in the moulding pathway direction relative to that mould when
engaging,
2o disengaging and when engaged in that mould. As indicated earlier, one
significant
advantage of the injection station is the lack of relative movement of the
nozzle with the
mould when engaging, disengaging and whilst engaged which means that alignment
is
achieved in a linear direction.
Following injection and a short period of in-mould cooling as the mould
devices (222)
move along moulding pathway (221 ), the actuators (not shown) are actuated to
open the
moulds. Once the moulds are open they are lifted by transfer means (not shown)
to
transfer the formed articles to the cooling devices (231 ) and are aligned
with the cavities of
the cooling devices (231 ) mounted above the moulding position.
The actuators engage the second mould parts with the cooling devices (231 ) to
effect
3o transfer of the formed articles to the cooling devices (231). A vacuum is
applied to the
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cooling devices (231) to transfer and support the formed articles which are
still relatively
soft. The formed articles continue along the moulding pathway (221 ) held in
the cooling
devices (231 ) before discharge from the mould device (222) by inversion.
Whilst this is
occurring, the second mould parts have returned to the moulding position ready
for the
next moulding cycle.
The cooling stations (231) rotate or tilt outwardly and are eventually
inverted to eject the
finished articles to a receiving station such as a hopper or packing system
(not shown).
During this phase of the cycle, the vacuum holding the cooled articles is
progressively
turned off and a positive ejector is applied to release the articles from the
cooling devices
(231). The cooling devices are tilted out to direct the cooled articles down
before ejection
into the packing delivery system.
Figure 13 illustrates a typical machine cycle in accordance with one
embodiment of the
invention. It will be seen from Figure 13 that the cycle involves injection of
moulding
material into moulds for forming at least one set of articles in the injection
zone and the
concurrent cooling of at least one separate set of formed articles during the
cycle. Hence
in one cycle, moulding material is injected into plural closed moulds as the
moulds pass the
injection zone 240.
As the moulds pass along the moulding pathway (241 ) they experience a period
of in-
mould cooling in zone 242, following which the mould parts are disengaged at
zone 243
2o and the second mould parts (also referred to in Figure 13 as a core block)
are raised to
deliver formed articles to a cooling station at zone 244. A vacuum is applied
to the second
mould parts and articles are transferred to the cooling devices in zone 245.
The now empty second mould parts disengage from the cooling devices in zone
246 and
are lowered back to the moulding position in zone 247. The moulds are closed
in zone 248
and are now ready for injection of further moulding material. Concurrently,
the articles
cooling in the cooling devices in zone 249 pass along moulding pathway 241 and
are
gradually ejected from the cooling devices in ejection zone 250. Further
moulding
material is injected into the moulds in injection zone 240 and the cycle is
repeated.
In Figures 14 and 15, an alternative injection station is schematically shown,
which
3o comprises a wheel (270) having a central injector cylinder (271) providing
moulding
CA 02383062 2002-03-13
WO 01/19585 PCT/AU00/01099
material from a bulk feed supply (272) to the nozzles (273) for supply of
moulding
material through the inlet ports of mould devices passing the injection
station.
The nozzles (273) are arranged about the periphery of the radial device, each
nozzle is
connected to a radial arm (274) which is also connected at its other end to a
hub device
5 (275. That hub device (275) is in turn connected to the central injector
cylinder (271).
In this arrangement each nozzle (273) has a valve, the opening and closing of
which is
controlled by the controller (not shown). Consequently, in this arrangement
individual
injection cylinders associated with each nozzle is avoided and a relatively
simple array of
valves can be used to deliver moulding material to the moulds from central
injector
to cylinder (271) via hub device (275), arms (274) and nozzles (273). However
the advantage
of the lack of relative movement between the nozzle and the mould is still
achieved.
The word 'comprising' and forms of the word 'comprising' as used in this
description and
in the claims does not limit the invention claimed to exclude any variants or
additions.
Modifications and improvements to the invention will be readily apparent to
those skilled
15 in the art. Such modifications and improvements are intended to be within
the scope of this
invention.
