Bottles and jars – Attachment or adjunct – Container support
Reexamination Certificate
1999-10-21
2001-01-30
Castellano, Stephen (Department: 3727)
Bottles and jars
Attachment or adjunct
Container support
C220S767000, C220S770000, C220S771000
Reexamination Certificate
active
06179143
ABSTRACT:
BACKGROUND OF THE INVENTION
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.
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 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 liter 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 arc 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 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 utilised it is possible to injection mould a handle which is narrower 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.
SUMMARY OF THE INVENTION
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;
(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 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 to effect engagement of the 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 between 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 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
Castellano Stephen
Continental PET Technologies Inc.
Wolf Greenfield & Sacks P.C.
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