Package making – Methods – Forming or partial forming a receptacle and subsequent filling
Reexamination Certificate
1998-12-24
2001-02-13
Coan, James F. (Department: 3721)
Package making
Methods
Forming or partial forming a receptacle and subsequent filling
C053S237000, C053S263000, C053S474000
Reexamination Certificate
active
06185911
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention concerns a method for filling a two chamber tube made from plastic and having a substantially circular cross section with a separation wall made from plastic extending between two substantially diametrically opposed connection points of the tube wall, and having a length in excess of the diameter of the tube and which, together with the walls of the tube, defines the two chambers, wherein a filling nozzle is inserted into each chamber for introduction of a filling product, with the tube being sealed after the filling nozzles have been removed. The invention also concerns an apparatus for carrying out the method having a filling unit and a downstream sealing unit for sealing the filled tubes.
Two chamber tubes made from plastic have been known in the art for some time and have the advantage of being able to accept two differing materials in one tube without having the materials come into contact with each other as is e.g. necessary with a two-component glue. A two chamber tube is manufactured from an initially flat multi-layered structure, wherein a plastic layer forming the separation wall is disposed between an upper and a lower tube wall layer. The tube is then subsequently erected to an approximately circular shape, wherein the separation wall, which should diametrically extend within the tube, is significantly longer than the diameter of the tube. In consequence of this excess length, the separation wall does not extend in a linear fashion, rather is curved with unpredictable shape.
A filling nozzle must be introduced into each of the two chambers to fill same. It has turned out that the uncontrollable position of the separation wall often interferes with introduction of the filling nozzles or causes both filling nozzles to be inserted into the same chamber so that the filling process has to be interrupted.
In order to prevent improper filling of the two chamber tube one has attempted to monitor the position of the separation wall prior to the filling procedure using video techniques in order to screen tubes having an undesirable wall position. This process is however difficult from a technical point of view and therefore expensive and leads to a very high fraction of rejected tubes which can not be filled.
It is therefore the underlying purpose of the invention to create a method of the above mentioned kind with which two chamber tubes can be filled in a reliable fashion as well as an apparatus with which the method can be carried out in a simple and economical fashion.
SUMMARY OF THE INVENTION
With regard to the method, the above mentioned purpose is achieved in that the separation wall is attached, at the end regions bordering the connection points, to the inner side of the tube wall prior to introduction of the filling nozzles in such a fashion that the length of the remaining middle region between the end regions corresponds substantially to the diameter of the tube.
In accordance with the invention, a tightening of the separation wall is thereby effected. The end regions of the separation wall, in consequence of their attachment to the walls of the tube, substantially follow the contours thereof and the middle region of the separation wall between the end regions extends substantially linearly in a diametric fashion relative to the circular shaped cross section of the tube. In this manner, a defined separation wall dependence is effected so that the filling nozzles can be introduced with high precision into the chambers defined by the tube walls and the separation wall. Hindrance of the filling procedure by an unchecked position of the separation wall is thereby prevented.
In order to guarantee that the end regions seat evenly on the inner side of the tube wall, a preferred embodiment of the invention provides that the end regions of the separation wall are connected over a large area to the tube wall.
An improvement of the invention provides that the end regions of the separation wall are welded to the surface of the tube wall. The welding can thereby be carried out in such a fashion that the end regions can be detached from the tube walls after the tube is filled. Instead of surface weldment, other kinds of connections, such as gluing can be used.
In order to advantageously achieve a large area welding connection between the tube wall and the separation wall a preferred embodiment of the invention provides that a heated shaping head be introduced into the tube to tension the separation wall and hold the end regions of the separation wall in a predetermined aligned fashion. Pressing jaws are then driven, from outside of the tube, against the sections of the shaping head holding the end regions of the separation wall so that the tube wall and the associated end regions of the separation wall are disposed between the shaping head and the associated pressing jaw. Heating via the shaping head leads to connective bonding between the separation wall at the end regions thereof and the inner surface of the tube wall.
One must avoid damage to the central region of the separation wall during the connection procedure. Towards this end the shaping head preferentially has a groove in which the central region of the separation wall can be accepted substantially without contact.
When the separation wall is only surface connected to the tube walls, only a small amount of heat must be introduced by the shaping head. The outer pressing jaws can thereby be neither heated nor cooled.
The above mentioned purpose is achieved with regard to an apparatus in that the filling unit comprises an upstream shaping unit having a heated shaping head which can be introduced into the tube to hold, in an aligned manner, the end regions of the separation wall with the assistance of seating surfaces and with pressing jaws disposed on the outer side of the tube which can be driven against the seating surfaces of the shaping head. It is thereby possible to directly provide the above mentioned alignment and tensioning of the separation wall within the tube filling machine as an additional processing step immediately preceding the actual filling process so that increases in time and technical effort can be kept to a minimum.
Since the end regions of the separation wall which are to be connected to the tube wall are disposed substantially diametrically across from each other, the seating surfaces are preferentially formed at opposite sides of the shaping head. The groove which accepts the middle region of the separation wall without contact extends between the two seating surfaces within the shaping head to thereby subdivide the shaping head into two introduction sections.
In order to simplify introduction of the shaping head into the tube and, in particular, reliably guarantee capture of the separation wall within the groove, a further improvement of the invention provides that the introduction sections of the shaping head each have guiding surfaces on the introduction sides facing the tube. This can e.g. be achieved if the guiding surfaces are tilted with respect to each other in such a fashion that the introduction sections have a shape tapering down towards their lower free end.
The seating surfaces are normally parallel to each other. The groove connecting the seating surfaces can extend perpendicular thereto. It has however turned out to be advantageous when the groove extends at an angle relative to the seating surfaces, whereby an acute angle between the corresponding seating surface and the associated section of the groove on the order of magnitude of approximately 60° to 70° has turned out to be useful. This causes the middle region of the separation wall to extend substantially diagonally within the groove with only point contact with the wall of the groove in the vicinity of the transition to the seating surfaces. In order to prevent the middle region of the separation wall within the groove from seating on a wall of the groove or the sides thereof, the sides of the groove can each have a recess extending along the entire groove length or at least along
Frey Herbert
Hähnel Bernd
Coan James F.
IWK Verpackunsgstechnik GmbH
Vincent Paul
LandOfFree
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