Note: Descriptions are shown in the official language in which they were submitted.
CA 02205137 1997-OS-12
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I-I-1ANDLED PLASTIC CONTAINER
This invention relates to a handled plastic container in which the container
is formed by blow moulding a preform and the handle is separately formed and
then connected to the container during the container forming process.
PIasYic containers for holding liquids including beverages and other
domestic liquids are in wide spread use. During the 1980's plastic largely
replaced glass as the material of first preference for the packaging of
carbonated
soft drinks. Plastics such as polyethylene terephthalate (PET) offer
significant
savings when compared with glass in packaging such products. Plastic is
lighter
than glass and plastic bottles are cheaper to make and cheaper to transport
than
glass bottles. In addition, there are clear safety advantages when using
plastic
given the inherent problems with breakages when using glass. Plastic
containers
are also in wide use for products such as detergents and fruit juices. Such
products are generally packaged in one or two litre containers with relatively
large
outlet openings. For ease of pouring, containers such as those made from PVC
often include a handle. In the past, the handle in plastic containers formed
by
extrusion blow moulding have been provided by blow moulding a hollow and
integral handle portion into the container side wall. Given the constraints of
container design, such handles are generally quite broad and often leave
little
room for one to firmly grasp the inside of the handle. Special moulds are
required
in the production of such bottles, they are more difficult to blow mould than
a non
handled bottle and there are difficulties with stress concentrations leading
to
possible container failure in the areas near the junction of the handle with
the rest
of the container.
In addition, it has not been generally possible to economically produce
such handled bottles from synthetic polyesters such as PET. To extrusion blow
mould PET it would be necessary to use a resin having a high intrinsic
viscosity
(i.e. well over 1.0). Such containers would not have the same degree of side
wall
orientation as a container stretch blow moulded from a preform. If an integral
handle was formed in a PET container formed from a preform, special cutting
tooling would be required to remove the flashing formed between the container
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side wall and the integrally formed handle due to the high orientation of the
material.
An alternative is the use of a separate handle joined to the container. If a
separate handle is ufilised it is possible to injection mould a handle which
is
har<oweP and thinner than the integral handles of the previously described
blow
moulded containers and if adequately attached to the container such handle
designs are more effective and easier to use.
Various attempts have been made to attach separate handles to blow
moulded containers formed from preforms but these have not been altogether
successful. One difficulty has been inadequate engagement of the handle with
the blow moulded container. A further difficulty has been the relative
slowness of
the processes used to produce such containers.
It is an object of the present invention to provide a method of securing a
separate handle to a plastic blow moulded container which enables relatively
rapid manufacture and which leads to the production of a handled bottle where
the handle is firmly secured.
In accordance with the present invention, the applicants have developed a
modified preform having a moulded engagement portion adapted to engage with
part of a separately formed handle. In the past, it has been proposed that
such
handles be connected to the plastic container by blow moulding the walls of
the
container around retaining portions provided at the respective ends of the
handle.
For eXample, reference is made to Australian patent 637,696. The' present
invention provides for engagement of at least part of the handle with an
engagement portion which is preferably rigid and which is not subject to
stretching
during the blow moulding process.
Thus, in accordance with one aspect of the present invention there is
provided a method of manufacturing a handled plastic container which includes
the steps of:-
(a) positioning a preformed handle and a synthetic resin preform within an
open blow mould without mutual engagement of said handle and preform;
said handle including upper retaining means and lower retaining means
and said preform including a moulded engagement portion adapted to
engage with the upper retaining means of the handle;
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(b) causing the upper retaining means of the handle to interconnect with the
engagement portion of the preform after the handle and preform have
been separately positioned within the blow mould; and
(c) stretch blow moulding the preform in the blow mould wherein said blow
moulding stretches the preform beneath the engagement portion into the
blow mould to form a container and expands the side wall of the preform
so to retain the upper retaining means of the handle in interconnecting
relation with the engagement portion of the preform and so to secure and
integrate the lower retaining means of the handle within the body of the
formed container.
In another aspect of the invention there is provided a method of
manufacturing a handled plastic container which includes the steps of:
a) positioning a preformed handle and a synthetic resin preform within
an open blow-mould without mutual engagement of said handle and
preform; said handle having an upper retaining means in an upper
portion of said handle and a free end and said preform including a
moulded engagement portion adapted to engage with said upper
retaining means of the handle;
b) causing the upper retaining means to interconnect with the
engagement portion of the preform after the handle and the preform
have been separately positioned within the blow mould; and
c) stretch blow moulding the preform in the blow mould wherein the
said blow moulding stretches the preform beneath the engagement
portion into the blow mould to form a container and expands the
side wall of the preform so to retain the upper retaining means of the
handle in interconnecting relation with the engagement portion of
the preform.
The upper retaining means of the handle may be interconnected with the
engagement portion of the preform either prior to or after the closing the
blow
mould. Preferably, the handle and preform are disposed within the open blow
mould so that the upper retaining means of the handle is adjacent to but not
interconnected with the engagement portion of the preform. The blow mould is
thereafter closed and the preform pushed down so io effect engagement of the
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upper retaining means within the moulded engagement portion. Preferably the
blow mould is shaped so to allow the preform to be moved downwardly from its
original position within the blow mould by a distance of befween about 1 to 4
mm
so to enable interconnection of the preform with the handle. Conveniently, the
preform is pushed down by the blow nozzle intended for use in introducing the
t
high pressure gas into the preform to cause stretch blow moulding.
Preferably the handle and the preform can be positioned within the blow
mould substantially simultaneously. In a most preferred embodiment the handle
and preform are positioned in the mould by a single transfer arm which holds
them both but where the handle and preform are not mutually engaged with each
other. The handle may also be inserted into the blow mould marginally earlier
or
later than the preform and the side wall of the preform and the top of the
handle
may be respectively shaped so that the preform may slide across the top of the
handle when being positioned adjacent to the handle in the blow mould.
Preferably both the handle and preform are transferred into the blow mould
in planes which are substantially parallel.
The upper retaining means and the moulded engagement portion may be
of various shapes and configurations. Whatever the configuration, the
engagement portion on the preform should resist vertical (upwards) or
horizontal
detachment of the upper retaining means once interconnected.
Preferably, the upper retaining means of the handle is a lug or protrusion
disposed at or adjacent the end of the top of the handle. In such arrangement,
the moulded engagement portion of the preform is preferably in the form of a
flange located beneath a neck finish on the preform, the flange including a
depending lip so to provide a downwardly facing groove into which the lug or
protrusion at the end of the handle may be retained. Alternatively, the flange
may
include an aperture into which the lug may be inserted.
Some preforms used on the commercial stretch blow moulding of
containers include a flange beneath the container neck finish. This flange
(often
referred to as the "support ledge") has many purposes including the mechanised
transfer of the preform to and from a blow mould and the support of the
preform
within the blow mould during the introduction of high pressure gas to blow
mould
the container.
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Alternative arrangements of an appropriately shaped retaining means on
the handle and a co-operating engagement portion on the preform will be self
evident to persons skilled in the art. For example, it is possible to reverse
the
arrangements described above so that a downwardly facing lug is provided on
the
preform and an aperture or groove formed within an upper portion of the
handle.
Preferably, the upper retaining means of the plastic handle extends from a
curved support surface shaped to follow the geometry of the preform
immediately
beneath the moulded engagement portion. Such a support surface assists in the
positioning and location of the upper retaining means for proper erigagement
with
the moulded engagement portion of the preform. Where a support surface is
provided its inner diameter should match the outside diameter of the preform.
The arc length of the support ring may vary but it is found that it is easier
to insert
the handle into conventional blow moulding tools when the arc is relatively
short.
In the embodiment of the invention where the handle includes a support
surtace which follows the geometry of the preform, it is particularly
preferred that
the handle also include a recessed portion adjacent to the support surtace
which
comprises one or more ribs. In such arrangement, when the preform is blown,
the portion of the preform immediately adjacent the support surtace will
expand
into the recessed portion but less so in those areas comprising ribbing. As a
consequence, once the bottle is blown the ribs in the recessed portion will be
located within small indentations on the container and the ribs and
indentations
will thus co-operate to resist rotational movement of the handle.
The lower retaining means of the handle is preferably a lug or protrusion
extending from the lower end of the handle. It should be shaped so that on
blow
moulding of the preform expansion of the side wall will capture anc! secure
the lug
within the formed body of the container. It may be of various geometrical
shapes.
Most preferably a lug which incorporates a hook or other extension is utilised
so
to encourage secure engagement with the body of the container.
The handle may be of any suitable configuration. In one embodiment of
the invention, the container formed is blow moulded so to include a recess on
one
side suitable for accommodating the handle. Preferably, this recess includes a
ledge onto which the bottom part of the handle may rest. In this
configuration, it
is preferred that the handle be generally "C" shaped in configuration with the
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upper and lower retaining means being at opposite ends. In a particularly
preferred embodiment, the cross secfion of the handle is "U" shaped so to
include
terminal flanges and a connecting web. It is preferred that the terminal
flanges
face downwardly at the lower end of the handle so that a hollow is formed
under
the connecting web. In this embodiment, the lower retaining means may be a lug
extending from the web. When confgured in this way, the blow moulding of the
preform in the vicinity of the lug forms a container side wall which Ells the
hollow
formed by the flanges underneath the connecting web and thus securely retains
the tug in position.
The handle may also include reinforcing ribs. In the embodiment
described above in which the handle has terminal flanges extending from a web
so to create a hollow on the underside of the handle it is preferred to
strengthen
the terminal flanges with ribbing as this area is exposed to high forces
exerted by
the expanding side wall of the preform during the blow moulding process.
Preferably, the handle is formed by injection moulding. It is not necessary
that it
be made from the same plastics material as the bottle and it may be formed
from
a plastic such as high densify polyethylene, polypropylene, PET, recycled PET,
glass reinforced PET and glass reinforced high density polyethylene. The
handle
could also be made from a metal such as aluminium. The bottle and the handle
can be made from the same material and this is preferably PET or recycled PET.
This would enhance recycling of the bottle.
In accordance with a further aspect of the present inventioh there is
provided a preform suitable for use in the method hereinbefore described. In
particular, such a preform includes a base, an elongate side wall portion and
a
neck; the said neck including a preformed finish and beneath said finish an
outwardly extending flange; said flange including a moulded engagement portion
adapted to engage with either an aperture or lug on a handle. Preferably, the
engagement portion is in the form of a lip depending from the outer edge of
the
flange. The preform may be made from any stretch blow mouldable polymer.
Preferably, it is formed from a PET homopolymer or copolymer (whether virgin
or
regrind), or a multilayer structure which may include Layers consisting of one
or
more of PET, PEN, EVOH or other polymers used in multilayer technology.
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In accordance with a further embodiment of the invention, there is
provided a handled plastic container, said container comprising a blow
moulded plastic bottle and a separate handle interconnected thereto wherein
said handle comprises upper retaining means and lower retaining means and
said bottle includes a moulded engagement portion which is interconnected
with the upper retaining means of the handle and wherein the lower retaining
means of the handle is secured and integrated into the side wall of the
container.
In yet another aspect of the invention there is provided a handled
plastic container, said container comprising a blow moulded plastic bottle and
a separate handle having a free end and interconnected to said bottle at
another end by upper retaining means, said upper retaining means including a
lug or protrusion, and the bottle including a neck finish having an engagement
portion co-operable with said lug or protrusion connecting said upper
retaining
means with said bottle.
In accordance with one aspect of the present invention, there is
provided a handled plastic container, the container comprising a blow molded
plastic bottle having a neck finish and a separate handle, the neck finish and
handle being interconnected by an upper retaining means on the handle and
a molded engagement portion on the neck finish adapted to engage with the
upper retaining means of the handle in an upwardly/downwardly facing
engagement to resist vertical detachment, wherein the molded engagement
portion is not subject to stretching during blow molding of the bottle and
wherein the upper retaining means on the handle comprises a lug or
protrusion which extends upwardly.
In accordance with another aspect of the present invention, there is
provided a handled plastic container, the container comprising a blow molded
plastic bottle and a separate handle interconnected thereto wherein the
handle includes upper retaining means and lower retaining means, the upper
retaining means including a lug or protrusion, and the bottle including a neck
finish having an engagement portion positionable above the upper retaining
means and co-operable with said lug or protrusion for connecting the upper
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retaining means with the bottle, wherein the engagement portion comprises a
flange located on the neck finish which flange includes at least one of a
groove and aperture into which the lug or protrusion locates and wherein the
lower retaining means is integrated with a portion of a sidewall of the
bottle.
Preferred embodiments of the invention are hereafter described with
reference to the following drawings in which:-
Figure 1 is a fragmentary cross sectional representation of a preform
used in the invention;
Figure 2 is a perspective view of a handle suitable for use with the
preform shown in Figure 1;
Figure 2a is an enlarged perspective view of the area marked IIa in
Figure 2;
Figure 3 is an alternative handle design also suitable for use with the
preform shown in Figure 1;
Figure 4 is a perspective view of the handle and preform shown in
Figures 1 and 3 being placed within an open blow mould;
Figure 5 is a cross sectional view of 'the blow mould shown in Figure 4
with the preform and handle as initially positioned therein;
Figure 6 is a cross sectional view of the blow mould handle and
preform once the blow mould has been closed and the top part of the handle
has been interconnected with the preform; and
Figure 7 is a perspective view of a handled bottle made in accordance
with the invention.
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Figure 8 is a side elevation of an alternative handle suitable far use in the
present invention.
Figure 9 is a front elevation of the handle shown in Figure 8 as shown from
the side which faces away from the bottle to which it may attach.
In Figure 1 there is shown a preform generally designated by the numeral
1. It comprises a screw thread finish 2, an outlet opening 3, elongated side
wall
portion 4, a base 5 and a support ledge 6. It will be appreciated that the
screw
thread finish may be substituted by any other preformed finish known in the
art.
For example to accept a "clip-on" cap or an other suitable closure.
The support ledge 6 includes a lip 7 which depends from the edge of
flange 6 so to form a downwardly facing peripheral groove 8. The groove 8 and
lip 7 together form the required engagement portion necessary in the present
invention. The preform shown in Figure 1 is preferably injection moulded and
preferably formed from PET or recycled PET. If the preform is being formed
using regrind material, it is preferable to use a three or five multi layer
prefortn
which includes one or more regrind central layers with virgin material on
either
side as are known in the art. The configuration and composition of such
multilayer preforms are well known to those skilled in the art.
In Figures 2 and 2a, there is shown a first embodiment of a handle suitable
for use with the preform shown in Figure 1 to form a handled container. The
handle has upstanding flanges 9 and 10 which extend from the top of the handle
11 to the bottom of the handle 12. The flanges are interconnected by a web 13
which is slightly concave in profile. Flanges 9 and 10 are provided with
indentations 9a and 10a on either side of the handle towards the lower end. At
the upper end 11, there is provided a curved support surface 12a and a lug
13a.
Lug 13a is shaped so that it may be seated~behind lip 7 in groove 8 of the
preform
shown in Figure 1. The support surface 12a has a radius of curvature the same
as that as the outer wall 4 of the preform 1 in the portion 14 located
immediately
beneath flange 6. At the lower end 12 of the handle, there is provided lower
retaining means being lug 15.
In Figure 3, there is shown an alternative handle 16. Handle 16 is
substantially the same as the handle shown in Figure 2 except at the upper end
where the handle includes a raised engagement portion 17 which extends from
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the top of the support surface 12a along its full length. A recessed area 18
is
provided in the tower portion of the support surface 12a and the recessed
portion
comprises two ribs 19 and 20. The handle has a smooth profile 21 on one side
so to allow both the preform 1 and the handle to move together into the blow
mould in parallel planes.
In Figures 8 and 9, handle 111 has a protrusion 112 in the upper retaining
end 117 of the handle and a lower retaining end 113 which includes a
projection
114 and a rib 115 which are integrated into the side wall of the bottle when
blown.
Protrusion 112 is adapted to locate in peripheral groove 8 behind lip 7.
Handle
111 has a main body 116 which extends between the upper retaining end 117
and the lower retaining end 113 and includes a plurality of ribs 118, 119 to
facilitate easy handling by the user and to aid grip. The upper retaining end
117
includes recessed portions 120 on either side and an opening 121 which extends
all the way through upper retaining end 117 from a support surface 122 to the
rear part 123 of the upper retaining end 117.
The boftle of the invention is made in accordance with the following steps.
First, the preformed plastic handle 16 is transferred to an open blow mould 22
by
a transfer arm 23 as shown in Figure 4. The preform shown in Figure 1 is
preheated in accordance with standard methodology. It is thereafter
transferred
to the blow mould 22 by transfer arm 24. The preform 1 and handle 16 are
transferred into the blow mould substantially simultaneously. The handle fits
within cavity 25 and the preform within cavity 26.
In another embodiment not shown a single transfer arm may transfer both
the preform and the handle into the blow mould. In this embodiment, which is
particularly suited to the type of handle shown in Figures 8 and 9, there may
be
provided a pin on the transfer arm which locates in opening 121 and jaws which
press into recessed portions 120. The pin and jaws are located in a region
below
the part of the transfer arm which holds preform 1. As shown in Figure 5,
preform 1 and handle 16 are located adjacent to one another but are not
interconnected. Raised engagement portion 17 is positioned immediately below
groove 8. The blow mould halves are thereafter closed and a blow nozzle 27 is
moved down on fo the preform 1. Upon closing of the mould halves recessed
portions in the mould (not shown) may hold the handle and the transfer arm may
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be retracted. The stroke of the blow nozzle is sufficient fo move the preform
down so that engagement portion 17 locates within groove 8 so to interconnect
the preform and handle. Recess 26 includes a groove 28 which is deeper than
support ledge 6 so to facilitate the downward movement of preform 1. Figure 6
illustrates prefortn 1 and handle 16 positioned within the blow mould after
interconnection.
Once the blow mould has been closed and the. preform and handle
interconnected, a gas is then introduced into the preform 1 so to stretch and
blow
the preform beneath flange 7 into the closed blow mould 21 to form the
container.
In the blow moulding process, plasfic underneath the support surface 12
expands
and this pushes the handle insert further up into the groove 8 thereby further
securing the handle into position. This restricts upldown movement of the
handle.
The plastic also expands around the sides of the support surface 12 and this
restricts the sideways movement of the handle once the container has been
blown. The sideways movement is further restricted by ribs 19 and 20 and
corresponding indentations 19a and 20a.
The lower end 12 of handle 16, lug 15 becomes surrounded by plastic
which expands upwardly to fill the recess formed between flanges 9 and 10.
Retaining lug 15 surrounded by the plastic resists sideways or horizontal
movement and This resistance of movement prevenfs retaining portion 16 from
being fevered out of the groove 8.
The container so formed is shown in Figure 7. It is noted that the handle
16 is designed so that it fits within the overall widthldepth of the bottle.
This
facilitates easy package and transport of the bottle in that the handle will
not
interFere with cartons and boxes.
The bottle shown in Figure 7 has a recess 29 which includes a ledge 30 on
which the lower portion of handle 16 sits. The bottle preferably includes side
wall
ribbing 31 to strengthen the walls against crushing.
In use, the bottle of the present invention has significant advantages over
prior art arrangements. The dimensions of handle permit easy access for the
uses hand. It is strengthened due to the "U" shaped cross section and this
cross
section also facilitates easy use of the handle as the groove thereformed in
the
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top of the handle enables the user to place his Thumb in the concave section
enabling easy stabilisation of the bottle as it is lifted and poured.
Once liquid has been removed from the container, the container may be
crushed at point 32 shown in Figure 7. This facilities easy removal of the
handle
from the bottle as a whole. This easy removal is useful in recycling. If the
handle
is formed from a different material to the bottle then contamination can be
minimised and even if the handle is made from the same material as the bottle,
then removal may be desirable as different processing is often required in
recycling thicker and harder materials as would preferably be used in a handle
as
compared with the thin and flexible blown container.
Thus, the present invention provides a container which is easy to use,
simple to dismantle after emptying for recycling and which can be readily
manufactured from a preform on blow mould apparatus at a relatively rapid
rate.
It will be appreciated that various modifications and additions may be made
to the preform, the handle and the bottle as hereinbefore described without
departing from the spirit and ambit of the present invention.
