Package making – Methods – Closing package or filled receptacle
Reexamination Certificate
2000-07-14
2003-06-10
Sipos, John (Department: 3721)
Package making
Methods
Closing package or filled receptacle
C053S167000, C053S237000, C053S371800, C053S375400, C053S481000, C053S567000
Reexamination Certificate
active
06574946
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to packaging tubes of the so-called flexible type, i.e., tubes with a tube body manufactured from material which allows the body to be squeezed for emptying the packaging contents. More precisely,, the present invention relates to flexible packaging tubes with an intermediate wall which forms two product-receiving compartments in the tube, the compartments being separated from one another.
Such packaging tubes are used for allowing the containment of different product types as well as for delivering a mixture of the products which is obtained in-situ.
The present invention is intended to provide a method and apparatus for end closure of such intermediate wall tubes, as distinguished from so called twin tubes (see for instance applicant's own International Application No. WO 94119251).
BACKGROUND OF THE INVENTION
Tubes with intermediate walls are manufactured, inter alia, by starting from web-like flexible material, e.g., polyethylene, polypropylene or other thermoplastic materials, in a longitudinal direction, by joining, along a pair of welded seams, a material layer serving as an outer tube wall to a material layer serving as an intermediate wall, which intermediate wall material layer is normally thinner than the outer material layer. The width of the outer material web is thereby larger than the width of the material web which is intended to form the intermediate wall, and the relationship between the widths is often chosen so that after longitudinal sealing of the outer layer and forming this into a circular tube, the intermediate wall presents a length over the cross-section of the tube which exceeds the diameter of the tube. The length of the intermediate wall is often chosen so that it corresponds to half the circumference of the tube, which means that with so-called planar sealing of the filling end of the tube, the intermediate wall presents the same length as the flattened tube end during sealing, as well as afterwards.
It has, however, shown itself to be the case that this surplus of length in the intermediate wall, which can be advantageous in the ready-sealed tube end, results in difficulties, even at the filling stage.
In order to overcome this, the applicant previously produced a method and device (WO 98/54054, priority date May 27, 1997), which allows the introduction of the filling nozzle on respective sides of the intermediate wall. Two relatively well-defined spaces in the closure end of the packaging tube are thereby created by the intermediate wall being stretched and spot welded to the inside of the tube at two substantially diametrically opposed positions.
This spot welding is done in a filling machine and, for continued efficient handling in the machine after filling with product/products, the filling end of the tube with corresponding end of the intermediate wall has to be capable of being sealed in a rational manner to form an end closure.
Tubes with intermediate walls are also manufactured by injection molding, in one-piece, a tube body, breast and intermediate wall.
Due to this manufacturing method, the intermediate wall in this case is of a thicker material as compared to the first-mentioned type of intermediate wall tube.
The greater material thickness results in problems with sealing the tube end.
In order to achieve such sealing, the intermediate wall has been allowed to finish at a distance from the tube end. With the aid of contacting heated jaws, heat energy from the outside of the tube is supplied to the inside of the tube in an encircling end area of the tube at a level above the intermediate wall.
Thus, in the tube filling machine, directly after the heat-activation station following the embossing station, embossing jaws operating perpendicularly to the intermediate wall during the entire sealing process have been used to press the ends of the tube together in the encircling end area in order to thereby create a seal.
However, such a seal does not always ensure the production of a joint which is free of passages between the two product containing compartments, which the intermediate wall is intended to achieve.
One object of the present invention is to solve the problem of end closure of packaging tubes of the types mentioned above, and to provide a solution which, while maintaining productivity in a tube filling machine, provides a complete handling of intermediate wall tubes, in principle in a manner which is equal to the highly effective handling of conventional tubes.
The solution to these problems should furthermore be such that a minimum of disturbance is required in existing tube filling lines.
SUMMARY OF THE INVENTION
In accordance with the present invention, these and other objects have now been realized by the discovery of a method for the end closure of a packaging tube including a tube body having a filling end and an intermediate wall forming a pair of separated product-receiving compartments, the intermediate wall extending across the tube body substantially along the entire length of the tube body along a first pair of circumferentially spaced joining locations, and a second pair of circumferentially spaced joining locations at the filling end of the tube body, whereby predetermined portions of the intermediate wall are formed between each of the second pair of circumferentially spaced joining locations and each of the first pair of circumferentially spaced joining locations, the method comprising heat activating the intermediate wall and the inside of the tube body by inserting a hot air nozzle including a pair of sub-members forming a gap therebetween into the area of the filling end of the tube body without direct contact with the packaging tube while applying a forming tool externally to the filling end of the tube body whereby the cross-sectional dimension of the filling end is compressed in both the horizontal and vertical directions, the intermediate wall is maintained in a stretched condition in the filling end of the tube body and both of the predetermined portions of the intermediate wall are brought closer to the inside of the tube body than before application of the forming tool, subsequently removing the hot air nozzle, and clamping the packaging tube so as to seal the filling end of the tube body.
In accordance with one embodiment of the method of the present invention, the tube body comprises a substantially elliptical shape and the intermediate wall is stretched across a minor axis of the filling end of the tube body, and wherein the applying of the forming tool externally to the filling of the tube body provides a cross-sectional dimension of the tube end having a substantially right-angled, four-sided shape. In a preferred embodiment, the pair of sub-members of the hot air nozzle comprise a pair of substantially identical sub-members defining substantially a right-angled cross-sectional dimension forming the gap adapted to receive the intermediate wall.
In accordance with another embodiment of the method of the present invention, the method includes inserting the hot air nozzle into the area of the filling end of the tube body so that the concentration of heat energy obtained on the intermediate wall is provided at portions of the intermediate wall between the first and second pairs of circumferentially spaced joining locations.
In accordance with the present invention, apparatus has also been discovered for the end closure of a packaging tube including a tube body having a filling end and an intermediate wall forming a pair of separated product-receiving compartments, the intermediate wall extending across the tube body substantially along the entire length of the tube body along a first pair of circumferentially spaced joining locations and a second pair of circumferentially spaced joining locations at the filling end of the tube body, whereby predetermined portions of the intermediate wall are formed between each of the second pair of circumferentially spaced joining locations and each of the first pair of circumferentially spaced joining locati
Desai Hemant M.
Lerner David Littenberg Krumholz & Mentlik LLP
Norden Pac Development AB
Sipos John
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