Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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1EIANDLED PLASTIC CONTAINER
Field of the Invention
This invention relates to a handled plastic container in which the container
is
formed by blow molding a preform and the handle is separately formed and then
connected to the
container during the container forming process.
Background of the Invention
Plastic 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 choice 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 molding has been provided by blow molding a hollow
and integral
2o 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 molds are
required in the production of such bottles, they are more difficult to blow
mold 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 mold PET it would be necessary to
use a resin
having a high intrinsic viscosity, i.e. well over 1Ø Such containers would
not have the same
degree of side wall orientation as a container stretch blow molded from the
preform.
3o If an integral handle was formed in a PET container formed from a preform,
a
special cutting tooling would be required to remove the flashing from between
the container side
wall and the integrally formed handle due to the high orientation of the
material.
RECTIFIED SHEET (RULE 91)
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An alternative is the use of a separate handle joined to the container. If a
separate
handle is utilized, it is possible to injection mold a handle which is
narrower and thinner than the
integral handles of the previously described blow-molded 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 molded
containers formed from preforms but these have not been altogether successful.
One difficulty
has been inadequate engagement of the handle with the blow molded container.
For example, it
has previously been proposed that such handles be connected to the plastic
container by blow
molding the walls of the container around retaining portions provided at the
respective ends of
1o the handle. For example, reference is made to Australian patent 637,696. In
processes where the
handle is pre-engaged with the preform prior to positioning the combination
into the blow mold,
there are problems in automating the whole process. The need to interconnect
the handle with
the preform prior to introducing the combination into the blow mold
complicates the
manufacturing process and can slow it down. This is especially so if the
interconnection process
15 occurs in a different direction to the direction of insertion of the
combination into the blow mold.
Summary of the Invention
It is an object of the present invention to provide a method of securing a
separate
handle to a plastic blow molded container which enables relatively rapid
manufacture and which
20 leads to the production of a handled bottle where the handle is firmly
secured.
In one embodiment, the invention utilises a molded external flange which is
not
subject to stretching during the blow molding process and which provides a
rigid support, against
which an upper end of the handle is held by a portion of the side wall of the
container once the
preform has been blown.
25 This embodiment thus achieves the desired object by positioning a preform
and a
handle into a blow mold and thereafter stretch blow molding the preform in
such a way as to
sandwich the upper end of the handle between a portion of the side wall of the
formed container
and a substantially flat underside of a molded external flange located on the
neck of the preform.
This simplifies the construction of the handle and preform, as well as
simplifying the positioning
30 of the preform and handle during blow molding to thus reduce the overall
cost of manufacture,
while providing a secure attachment.
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More particularly, in accordance with one embodiment of the present invention
there is provided a method of manufacturing a handled plastic container which
includes the steps
of:
(a) positioning in an open blow mould a synthetic plastics preform which
includes an
external flange with a substantially flat underside face, and a handle which
includes
an upper end with a substantially flat abutment surface;
(b) closing the blow mould and stretch blow moulding the preform beneath the
flange
to form a container, wherein a sidewall portion of the preform is expanded so
as to
sandwich the upper end of the handle between a portion of the sidewall of the
1o formed container and the flange with the substantially flat upper abutment
surface
and underside face being pressed together so as to fixedly connect the handle
to the
blown container.
Preferably the preform and handle are brought together into position where the
upper end of the handle is adjacent to the underside of the external flange by
relative movement
15 of the preform and the handle towards each other along a first path which
is substantially
perpendicular to a longitudinal axis of the preform.
Most preferably, the preform and handle are brought together into this
position
prior to their introduction into the blow mould. In such case, it is preferred
that the handle and
preform once brought together be introduced into the blow mould together along
a second path
2o which is also substantially perpendicular to the longitudinal axis of the
preform. The first and
second paths may conveniently be in the same plane so that the handle and
preform may be
brought together and conveyed into the open blow mould by movement along a
path which has
no abrupt changes in direction.
Generally, the method of the invention is used with blow moulding equipment
25 which requires that the preform be pre-heated before introduction into the
blow mould to a
temperature at which it may be stretched and blow moulded (e.g., in the glass
transition range).
Therefore, generally the preform is hot and the handle is cold when the two
are positioned in the
mould.
It is preferred that the preform and the handle be unconnected when positioned
in
3o the open blow mould. However, in one embodiment of the invention further
described below
where the handle is attached to the container only at its upper end, it is
preferred that the upper
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end of the handle be broad enough to clip around the preform immediately
beneath the external
flange.
Preferably, the upper end of the handle also includes retaining means such
that
upon expansion of the sidewall of the preform, the retaining means is caused
to interconnect with
a portion of the formed container. Most preferably, the retaining means is
adapted to be
integrated with a portion of the wall of the container. The retaining means
may take a number of
different configurations. For example, it can comprise a downwardly facing
projection, such as a
lug or hook. In such an embodiment, the downwardly extending projection is
adapted to firmly
integrate and interconnect with the plastic material forming that part of the
side wall of the blown
1o container adjacent the external flange.
The preform may be of any suitable shape for forming a container. In some
cases,
it is preferred that the body of the preform be wider than the external
flange. This is particularly
so for the manufacture of larger containers. It is preferred that the upper
end of the handle
include a support platform with a curved front face which is shaped to conform
against the outer
surface of the preform wall below the flange, and a flat top face which lies
against the flat
underside surface of the external flange.
The external flange on the preform should resist vertical (upwards) detachment
of
the handle and the upper end of the handle should be pressed against the
underside of the
external flange so to resist horizontal detachment. The method of the present
invention enables
one to produce a handled plastic bottle in which the upper end of the handle
is fixedly connected
to the blown container at a location immediately beneath the external flange.
The other end of
the handle does not need to be connected to the container and in such an
embodiment, the
depending gripping portion terminates at an unconnected free end.
In an alternative embodiment, the lower end of the handle may include lower
retaining means also adapted to be integrated within a portion of the wall of
the formed
container. The handle and the preform may be positioned within the blow mould
simultaneously
and may be positioned in the mould by a single transfer arm which holds them
both. The handle
and preform do not need to be exactly positioned with the upper end of the
handle in direct
abutment with the underside of the external flange of the preform. There may
be a small gap
3o between the two. If there is a small gap between the two after they have
been introduced into the
open blow mould, this can be rectified after the blow mould has been closed.
The blow mould
may be shaped so to allow the preform to be moved downwardly from its original
position within
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the blow mould by a distance of between about I to 4 mm so to push the preform
so that there is
direct abutment between the upper end of the handle and the underside face of
external flange.
Conveniently, the preform may be pushed down by the blow nozzle intended for
use in
introducing the high pressure gas into the preform to cause stretch blow
moulding.
Alternatively, the preform and handle may be separately introduced into the
open
blow mould on separate transfer arms, each moving in a substantially
horizontal plane. The
handle may be inserted into the blow mould marginally earlier or later than
the preform and the
side wall of the preform and the upper end 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
1o the blow mould.
Most 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
15 pressure gas to blow mould the container. Such preforms may be used in the
method of the
present invention.
Preferably, the upper end of the handle includes a support platform having a
curved
front face shaped to follow the geometry of the preform immediately beneath
the external flange.
Such a curved face assists in the positioning and location of the handle
adjacent to the preform.
2o Where a curved face is provided, the inner diameter of the curved face
should match the outside
diameter of the preform. The arc length of the face may vary but it is found
that it is easier to
insert the handle into conventional blow molding tools when the arc is
relatively short (between
to 15 °). However, in cases where the blow molding apparatus can
accommodate a broader
face it can be desirable for the arc length to be larger. As it is preferred
that the handle and
25 preform be brought together along a path substantially perpendicular to the
longitudinal axis of
the preform, the arc length of the curved face cannot be significantly greater
than 180°. If the
handle is made from a resilient plastics material the arms of the curved face
can extend around an
arc length of up to about 220° - the preform being capable of being
pushed through the opening
between the arms with the arms thereafter clipping around the preform body.
This arrangement
3o provides more secure attachment of the upper end of the handle to the
container once blown and
is preferred in cases where the lower end of the handle is not to be attached
to the container.
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In a particularly preferred embodiment the handle includes a support platform
with
a front face shaped to follow the geometry of the preform immediately beneath
the flange and a
retaining means is spaced below the support platform and extends toward the
preform such that
plastics material is molded about the retaining means to thereby lock the
retaining means within
the wall of the plastic container. The spacing between the support platform
and retaining means
will generally allow plastics material to pass between the retaining means and
support platform
adjacent the upper surface of the retaining means and the retaining means
preferably increases in
vertical dimension toward the preform. The retaining means may include
coacting upper and
lower tabs which vertically diverge and extend toward the preform to provide
increasing
1o dimensions. The molding of plastic material on opposite sides of the
coacting tabs locks the
handle with the container wall. The lower of the tabs preferably extends
downward so that
plastic is molded adjacent its outer side.
In the embodiment of the invention where the handle includes a curved face
which
follows the geometry of the preform the handle may also include a recessed
portion adjacent to
the curved face which comprises one or more ribs. In such arrangement, when
the preform is
blown the portion of the preform immediately adjacent the curved face will
expand into the
recessed portion but less so into 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
2o handle. Alternatively, or in addition, the blow mould may incorporate small
cavities positioned
to be adjacent the respective outside edges of the upper end of the handle so
to form blow
moulded lugs adjacent the respective edges of the handle at its upper end.
Such blow moulded
lugs will also 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 and 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
3o 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"
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shaped in configuration with the upper and lower retaining means being at
opposite ends. In a
particularly preferred embodiment, the cross section 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 configured
in this way, blow moulding of the preform in the vicinity of the lug forms a
container side wall
which fills the hollow formed by the flanges underneath the connecting web and
thus securely
retains the lug in position.
The handle may also include reinforcing ribs. In the embodiment described
above
to 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
I5 be made from the same material as the container and it may be formed from a
plastic such as
~j~: high density polyethylene, polypropylene, PET, recycled PET, glass
reinforced PET or glass
reinforced high density polyethylene. The handle may also be made from metals
such as
aluminium. The container and the handle are preferably made from the same
material. Most
preferably this is PET or recycled PET. The use of the same materials for both
container and
2o handle simplifies recycling of the combination.
The preform used in the present invention may be made from any stretch blow
mouldable polymer. Preferably, it is formed from a PET homopolymer or
copolymer (whether
virgin or regrind) or is a multi-layer structure which may include layers
consisting of one or
more of PET, PEN, EVOH or other polymers used in muitilayer technology.
25 In accordance with a further embodiment of the invention, there is provided
a
handled plastic container which includes a blow moulded plastic bottle which
has an external
flange proximate to its opening and a separate handle interconnected thereto,
wherein said handle
includes an upper end and a depending gripping portion, the said upper end of
the handle being
fixedly connected to the container being sandwiched between the underside of
the external flange
3o and a portion of the container side wall.
Preferably, the upper end of the handle includes a curved face shaped to
follow the
geometry of the preform immediately beneath the external flange. The curved
face is provided
with an inner diameter which matches the outside diameter of the container.
The arc length of
the support surface is preferably no greater than 220°.
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In a still further alternative embodiment, the upper end of the handle has a
diverging distal end which is spaced below the flange and integrated with an
upper dome portion
of the container.
These and other features of the present invention will be understood from the
following detailed description and drawings.
Brief Descrintion of the Figures
Figure 1 is a fragmentary cross-sectional representation of a preform used in
a
preferred embodiment of the invention;
1 o Figure 2 is a perspective view of a handle suitable for use with the
preform shown
in Figure 1;
Figure 3 is an enlarged perspective view of the area seen along Arrow III in
Figure
2;
Figure 4 is a perspective view of the handle and preform shown in Figure 1 and
2
t 5 placed within an open blow mold;
Figure 5 is a cross sectional view of the blow mold shown in Figure 4 with the
preform and handle positioned therein with the blow mold closed;
Figure 6 is a side view of a handled bottle made in accordance with an
alternative
embodiment of the invention;
2o Figure 7 is a side view of an alternative handle suitable for use in the
present
invention;
Figure 8 is a front perspective view of the handle shown in Figure 7;
Figure 9 is a perspective view of the top section of the handled container
shown in
Figure 6;
25 Figure 10 is a perspective view of a further alternative handle for use in
the present
invention;
Figure 11 is a cross-sectional view of the further alternative handle of
Figure 10
positioned with respect to the preform, and substantially blown container;
Figure 12 is a front perspective view of a further alternative handle for use
in the
3o present invention;
Figure 13 is a rear perspective view of the handle of Figure 12;
Figure 14 is a side view of the handle of Figure 12;
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Figure 15 is an exterior (rear) view of the handle of Figure 12;
Figure 16 is a cross-sectional view of a further alternative handle and
container,
with Figures 17 and 18 showing in greater detail the upper and lower handle
attachment portions
respectively.
Detailed Descri tion
In Figure 1 there is a preform generally designated by the numeral 1. It
comprises a
screw thread finish 2, an open end 3, elongated side wall portion 4, a closed
end 5 and an
external flange 6. It will be appreciated that the screw thread finish may be
substituted by any
other preformed finish known in the art. For example, the finish may be
modified to accept a
"clip-on" cap or other suitable closure.
'~'' The external flange 6 includes a top side 7 and an opposing underside
face 8, both
of which are substantially flat (planar). The preform shown in Figure 1 is
preferably injection
molded and preferably formed from PET and recycled PET. If the preform is
being formed
l5 using regrind material, it is preferred to utilize a three or five layer
structure in which one or
more regrind layers are encased within virgin material on either side as is
known in the art. The
configuration and composition of such multilayer preforms do not form any part
of the present
invention.
In Figures 2 and 3, there is shown a first embodiment of a handle 30 suitable
for
2o use with the preform shown in Figure 1 to form a handled container of the
invention. 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 l Ob 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 support platform 11 a
having a curved
25 front face 13 and an upper abutment surface 14. The upper surface 14 is
substantially flat and is
adapted to conform to (lie alongside) the underside face 8 of external flange
6. The upper end 11
also includes a downwardly extending lug 15. The curved front surface 13 has a
radius of
curvature the same as that as the outer wall 4 of the preform 1 in the portion
16 located
immediately beneath external flange 6. At the lower end 12 of the handle,
there is provided
30 lower retaining means being lug 17.
In Figures 7 and 8, an alternative handle 18 has an upper support platform 19,
with
a curved front face 28 and a flat top surface 22. The handle has a lower end
20 which includes a
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projection 21 that is integrated into the side wall of the container when
blown. Depending from
the upper support platform 19 is a downwardly-extending lug 15 which is
adapted to be
integrated into the side wall of the container when blown immediately beneath
the external
flange 6. Handle 18 has a main body 23 which extends between the upper
platform 19 and the
lower end 20 and includes a plurality of cross ribs 24 and 25 to facilitate
easy handling by the
user and to aid grip. The upper platform 19 includes recessed portions 26 on
either side and an
opening 27 which extends all the way through the platform 19 from the front
surface 28 to the
rear (outer) face 29 of the upper handle.
A container made in accordance with the preferred embodiment of the invention
is
1 o made in accordance with the following steps.
~..,~ First, the preformed plastic handle 30 shown in Figure 4 is transferred
to an open
blow mold 31 by a transfer arm 32a 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 mold
31 by transfer arm 32b. The preform 1 and handle 30 are transferred into the
blow mold
substantially simultaneously and in the same plane. The handle 30 fits within
cavity 33 (as
shown in Figure 5) and the preform 1 within cavity 34. In another embodiment
not shown, a
single transfer arm may be used to transfer both the preform and the handle
into the blow mold.
In this embodiment, which is particularly suited to the type of handle shown
in Figures 7 and 8,
there may be provided a pin on the transfer arm which locates in opening 27
and jaws which
2o press into recessed portions 26. 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
30 are located
adjacent to one another with abutment surface 14 in close proximity to the
underside face 8 of
external flange 6. Upon closing of the mold halves, the recessed portions in
the mold (not shown)
may hold the handle and the transfer arm may be retracted. Figure 5
illustrates preform l and
handle 30 positioned within the closed blow mold.
Once the blow mold has been closed, a gas is introduced into the preform so to
stretch and blow the preform beneath external flange 6. In the blow molding
process, plastic
underneath the flange 6 expands around the sides of the upper support platform
(1 la in Fig. 2; 19
in Fig. 7) and incorporates lug 15 into the side wall of the container. The
plastic underneath the
3o flange expands and this pushes the top flat surface (14 or 22) hard up
against the underside
surface 8 of external flange 6. The upper platform is thereby sandwiched
between the underside
face 8 of flange 6 and the upper blown wall portion so to securely hold it in
position. Lug 15
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restricts lateral movement. The plastic also expands around the sides of the
upper support
platform and this restricts the sideways movement of the handle once the
container has been
blown. The sideways movement is further restricted by ribs 35 and 36 (see
Figure 3) and
corresponding indentations in the blown container.
At the lower end of handle 30, the lug (17 in Fig. 2; 21 in Fig. 7) becomes
surrounded by plastic which expands upwardly to fill the recess between the
handle side flanges
(9 and 10 in Fig. 2). The retaining lug surrounded by the plastic resists
sideways or horizontal
movement.
The container formed using the handle illustrated in Figures 7 and 8 is shown
in
t o Figure 6. It is noted that the handle 18 is designed so that it fits
within the overall width/depth of
the bottle. This facilitates easy package and transport of the container in
that the handle will not
interfere with cartons and boxes.
The container shown in Figure 6 has a recess 37 which includes a ledge 38 on
which the lower portion 20 of handle 18 sits. The container preferably
includes side wall ribbing
t 5 39 to strengthen the walls against crushing. The top of this container is
shown in Figure 9.
Portions 41 and 42 are blown around the opposing sides of upper platform 19 to
further resist
rotational movement of the handle.
Once liquid has been removed from the container, the container may be crushed
at
point 40 shown in Figure 6. This facilitates easy removal of the handle from
the container as a
2o whole. This easy removal is useful in recycling. If the handle is formed
from a different
material to the bottle, then contamination can be minimized. If the handle is
made from the same
material as the bottle, removal may still 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.
25 Figures 10 and 11 show a preferred embodiment in which the handle 43 has an
upper end with a support platform 44 which includes a top flat surface 46, and
a curved front
surface 45 having a radius of curvature the same as the outer wall of the
preform in the portion
located immediately below the external flange 47. A retaining means 48 is
provided which is
spaced beneath the support platform and includes a pair of vertically
divergent tabs, upper tab 49,
30 lower tab 50 extending toward the preform (i.e., toward the longitudinal
axis 59 of the preform).
The tabs diverge toward their distal ends (which lie adjacent the preform
wall) so that a
dimension of the retaining means 48 in the vertical plane shown in Figure 11
increases toward
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bottle preform 58. In Fig. 10, two sets of arrows, A at the narrow point
(juncture with the
handle), and B at the widest point (toward the preform), show this divergence.
The preform 58 is blow molded within a mold in accordance with the general
procedure described with respect to Figure 4. Blow molding of the preform 58
causes the
plastics material of a portion of the preform wall 51 to be molded about the
retaining means 48
as shown in Fig. 11 so that a portion of the retaining means of increasing
dimension is locked
within the resulting container wall 52 with the top face 46 at the upper end
of the handle 44
abutting the underside of the flange 47. The upper part of the handle is
thereby retained during
lifting by opposing portions 53, 54 of the container wall 52 on opposite sides
of the tabs 49, 50
l o and the abutment of the top face 46 of the handle 43 on the underside of
the flange 47.
The lower tab 50 preferably extends downward and plastics material of the
molded
'°''' bottle is provided adjacent the outer side of the lower tab 55.
The preform 58 may include a cylindrical wall portion 56 immediately below the
flange 47 for receiving the support platform 44 and a portion 51 increasing in
wall thickness
below said cylindrical portion adjacent which the tabs 49, 50 extend.
Figures 12-15 show another preferred embodiment in which the handle 60 has an
upper support platform 61 which includes a flat upper surface 66, and a front
face 62 having a
radius of curvature the same as the outer wall of the preform in the portion
located immediately
below the external flange. A retaining means 63 is provided which is spaced
beneath the support
2o platform 61 by a wall portion 64. The retaining means includes a downwardly
extending tab 65
w-..l which extends toward the preform.
The preform is blow-molded within a mold in accordance with the general
procedure described with respect to Figure 4. Blow-molding of the preform
causes the plastics
material in a portion of the preform wall to be molded about the retaining
means 63. The upper
part of the handle is thereby retained during lifting by opposing portions of
the container wall on
opposite sides of the tab 65 and the abutment of the flat upper surface 66 of
the handle on the flat
underside of the flange.
The lower tab 65 preferably extends generally downward and plastics material
of
the molded bottle is provided adjacent the outer side 67 of the lower tab. The
lower tab is
3o preferably reinforced by a substantially vertical rib 68 which engages the
outer surface 67 of the
tab and the lower surface 69 of the adjacent handled portion. Similar
reinforcing ribs 70 are
provided on the outer surface of a downwardly extending tab 71 on the lower
end of the handle.
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In this embodiment, as in the embodiment of Figs. 10-11, the outer surface of
the
handle has vertically extending ribs between the outer flanges on the handle,
which fiirther
strengthen the handle.
The above embodiment 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 mold apparatus at a relatively rapid rate.
Figs. 16-18 show another preferred embodiment, similar to the embodiment of
Figs. 10-11 in utilizing a pair of divergent tabs as the upper handle
attachment means, but
eliminating the platform which sits along the preform flange. Here the upper
handle attachment
to is spaced below the preform/bottle flange and surrounded by an upper
portion of the blown
container dome (shoulder). This is particularly useful for polyester
containers used at elevated
temperatures, such as hot-fill containers, because this embodiment enables a
higher degree of
biaxial orientation (and therefore higher thermal stability) in the upper dome
portion of the
container. This increase in biaxial orientation not only improves the thermal
stability at the
I 5 upper end of the dome portion, but also increases the mechanical strength
of this portion to
enable secure attachment of the upper end of the handle.
More specifically, a PET container 80 has an open top end 81 with a threaded
finish 82 and flange 83. Below the flange there is an unstretched cylindrical
portion 84 (by
which the preform/container is supported below the flange during transport,
filling, capping, etc.)
20 and then a dome portion 85 having a relatively high degree of biaxial
orientation at its upper end
86 adjacent the cylindrical portion and flange. The container is stretch blow
molded from a
preform 95 similar to the preform in the prior embodiments, including the
cylindrical portion 84
below the flange 83, an outwardly-flaring tapered portion 96 which forms the
dome, and a
substantially cylindrical sidewall 97 which forms the main panel section 87 of
the container. In
25 this embodiment, the handle 100 is attached to the dome 85 of the
container, above the panel
section 87. A recess 88 is formed in the dome, providing a space for the
fingers to be inserted
through the handle. The handle 100 includes an upper attachment end 101 having
a pair of
vertically divergent tabs extending toward the preform (i.e., towards a
longitudinal axis 120 of
the preform), including an upper tab 102 and a lower tab 103. The upper
tapered portion 96 of
3o the preform is blow-molded about the tabs as shown, such that the blown
container dome 85
AMENDED SHEET
CA 02255027 1998-11-13
WO 97/43108 PCT/US97/09244
_ 1~ _
surrounds the outer sides 105, 106 of the tabs and engages the narrow portion
107 of the upper
handle attachment. The area 86 of the container dome above the upper handle
attachment
preferably has an average planar (biaxial) stretch ratio of greater than 2.5,
to provide the
enhanced thermal and mechanical strength as previously described. The upper
handle
attachment portion 101 is located in close proximity, e.g., about %z inch,
below the bottom of the
flange.
As illustrated in Fig. 17, the diverging tabs 102, 103 have a widest distal
point
defined by a width b, and a narrow proximal point 107 defined by a width a.
This anchoring
ratio b/a is preferably in the range of about 2-4, and more preferably about
3. In addition, the
upper attachment portion may also diverge (become wider) going from top to
bottom in order to
further secure the upper handle to the dome.
At the lower end of the handle, a lower attachment means 109 is provided which
is
incorporated into a lower portion 89 of the dome by blow molding the preform
around the lower
handle attachment portion. As shown in Figs. 16 and 18, this lower handle
portion is similar to
the upper handle attachment portion in having a diverging distal end 110
defined by a width b,
and a narrow proximal end 111 defined by a width a. Again, the preform is
blown around the
outer sides 112, 113 of the diverging end, in order to secure the handle to
the container. An
anchoring ratio b/a as described for the upper handle attachment portion above
is preferably
used. Alternatively, the lower handle attaching portion may be similar to the
upper handle
2o attaching portion (i.e., diverging tabs).
It will be appreciated that various modifications and additions may be made to
the
method, preform, the handle and the container as hereinbefore described
without departing from
the scope of the present invention.
