Metal working – Method of mechanical manufacture – Obtaining plural product pieces from unitary workpiece
Reexamination Certificate
2000-02-03
2002-08-20
Bryant, David P. (Department: 3726)
Metal working
Method of mechanical manufacture
Obtaining plural product pieces from unitary workpiece
C029S412000, C029S415000, C264S527000, C264S531000, C264S540000
Reexamination Certificate
active
06434812
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a method of manufacturing and handling parts for a packaging container.
BACKGROUND ART
Beverage packages for drinks of different types, for example fruit juices, sports drinks or other non-carbonated drinks occur on the market in a plurality of different forms. Plastic packages, for example blow moulded bottles or deep drawn beakers or cans are common on the market. Packages of laminated paper/plastic laminate as well as deep drawn aluminium cans are also common. A cost-effective packaging container presupposes low production costs, high production output rates (mass production) and an expedient choice of materials. The material type(s) of the package should be selected such that the properties of the material are adapted not only to the beverage which is to be packed, but also to the package type and its use. The properties of the material as regards, for example, mechanical durability, liquid-tightness and gas barrier properties should, in other words, be selected such that the material combination as a whole is not over-qualified in relation to its purpose, which, for example, might probably be considered the case when a deep drawn aluminium can is employed for non-carbonated products, since its mechanical durability is greatly over dimensioned and the desired barrier properties can be obtained with but an extremely thin layer of aluminium, or other barrier material. Deep drawn plastic bottles are also normally over dimensioned from the point of view of mechanical strength in the packing of so-called still drinks, and it may generally be ascertained that it is usual that precisely still drinks are often packed in far too exclusive and expensive packaging containers.
An optimum packaging container which is particularly intended for still drinks and which is also sterilisable and thereby suitable for aseptic packing of drinks is made up of several parts, e.g. a casing, a top portion, a bottom portion, and a closure arrangement, each one of these being adapted to its given purpose in view of material selection and method of production. By utilising a separate top portion, this may, for example, be made from stronger or mechanically more stable material so that application and handling of the closure arrangement can take place without the risk of damage to the packaging container itself. The handling of the individual packaging component parts may, however, entail certain difficulties, in particular in the manufacture of aseptic packaging containers. Apart from the obvious risk that the parts during handling (transport, assembly, sealing, etc.) are exposed to contaminants or bacteria, there is also an obvious risk of mechanical damage, for example chipping or scratching. In particular in aseptic packages, a bacteria-tight package is of decisive importance for the capability to retain the pristine quality of the packed product, and even very slight damage to, for example, the sealing or tightening surfaces of the packaging component parts may consequently be of major negative importance. This applies not least to the sealing and thread surfaces of the neck portion which are particularly vulnerable and sensitive.
It is known in the art to manufacture packaging containers or parts therefor, for example top or bottom portions, from different types of plastic materials which are formed by various, per se known techniques for the forming of thermoplastic. The top portion often includes closure arrangements or threads for screw caps, which increases the demands on the method of manufacture and the plastic quality employed for this particular part. For example, it is known to manufacture tops for packaging containers by injection moulding, which gives a high degree of accuracy and quality but impedes or renders impossible the production of tops with an integrated gas barrier layer, which, for example, is desirable in the packing of fruit juices. Another prior art forming technique is conventional thermoforming of a web-shaped heated material which in itself may include an integrated barrier layer. However, this method gives varying material thickness and a poorer level of part and detail accuracy, which has a negative effect on the possibility of forming with sufficient precision a neck portion with threading or other mechanical engagement regions for a closure arrangement.
A further, per se known technique for producing packaging containers is blow moulding, in which the starting material is preferably a freshly extruded plastic hose which in itself may include an integrated barrier layer of some suitable, per se known barrier plastic. With the aid of mould halves surrounding the plastic hose, and suitable pressure difference, the plastic hose may be given the desired packaging configuration. As mentioned above, the packaging container may, in such instance, include a barrier layer and the method also makes it possible to manufacture the packaging container with a high degree of accuracy also as regards such items as threaded neck regions, but the method suffers from a decisive drawback in the fact that it is comparatively slow, both in the extrusion of the requisite hose length for realising a packaging container, and also the cooling of the packaging container formed from the hose, as the packaging container must remain in the mould halves until such time as its temperature has fallen so that the material has become geometrically stable. The large and unevenly distributed plastic volume not only delays cooling but also entails an uneven cooling effect and, since positive cooling in practice is not feasible, this method must be deemed far too slow for the modern, high capacity production of packaging containers.
There is thus a need in the packaging industry and technology to realise a method which makes it possible, with high precision and great rapidity, to rationally manufacture parts for packaging containers while ensuring a minimum risk of handling damage, as well as a high standard of hygiene.
SUMMARY OF THE INVENTION
object of the present invention is thus to realise a method of manufacturing and handling parts for a packaging container, the method obviating the above-outlined drawbacks and making for rapid and rational manufacture, at the same time as handling is facilitated and contributes in reducing to a minimum the risk of mechanical damage which may jeopardise the gas and bacteria tightness of the finished packaging containers.
A further object of the present invention is to realise a method of manufacturing and handling parts for packaging containers which makes for rational manufacture and handling of packaging container tops, while maintaining a high standard of hygiene.
Yet a further object of the present invention is to realise a method of manufacturing and handling packaging container tops which makes it possible to protect the inner surface of the tops and reduces the need for cleaning and sterilisation.
Still a further object of the present invention is to realise a method of manufacturing and handling parts for a packaging container, the method being rapid and economical in terms of resources and, as a result, not suffering from the drawbacks inherent in prior art manufacturing methods, e.g. slowness, insufficient forming precision or high costs.
These and other objects have been attained according to the present invention in that a method of manufacturing and handling parts for packaging containers has been given the characterizing feature that a number of tops are produced in the form of a continuous row of pairwise reversed tops, each pair thereafter being separated from neighbouring pairs and provided with closure arrangements in the end portions exposed as a result of this separation.
Preferred embodiments of the method according to the present invention have further been given the characterizing features as set forth in appended subclaims
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REFERENCES:
patent: 1210842 (1917-01-01), Rickman
patent: 2501833 (1950-03-01), Webb et al.
patent: 2790994 (1957-05-01), Cardot et al.
patent: 3310620 (1967
Andersson Jan
Fredén Jan
Gustafsson Lennart
Johnsson Ulf
Bryant David P.
Burns Doane Swecker & Mathis L.L.P.
Fredén Jan
Omgba Essama
Tetra Laval Holdings & Finance S.A.
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