METHOD OF MANUFACTURING A CONTAINER

Abstract

The method for manufacturing a container having a substantially stiff outer container and a readily deformable inner bag of thermoplastic plastic materials which do not form a weld connection with one another, with a container opening and holes in the outer container, wherein the method includes forming holes in the wall of the outer container at diametrically opposed positions, which lie on the intersection line of a plane defined by the base seam and the longitudinal axis of the container with the container wall and that a pin-shaped tool forces the inner bag through the holes by a predetermined distance from the wall of the outer container and thereby detaches it from the wall, whereafter a pressure medium is introduced through the holes into the gap between the inner bag and the outer container, which detaches the inner bag from the wall of the outer container.

Claims

1. A method of manufacturing a container having of a substantially stiff outer container and a readily deformable inner bag of thermoplastic plastic materials which do not form a weld connection with one another, with a container opening and holes in the outer container, through which a pressure balance occurs in the gap between the inner bag and the outer container, wherein a preform including at least two tubes is coextruded and is arranged between the open halves of a blow mould and the blow mould is closed when the preform has the length necessary for the manufacture of the container, wherein excess material in the base region of the container to be manufactured is squeezed out and a web is formed of welded material of the outer container, in which the welded base seam of the inner bag is clamped and is held in the axial direction and the preform is inflated by a pressure medium into engagement with the wall of the blow mould and is removed from the blow mould, wherein the method of manufacturing comprises whereafter holes are formed in the wall of the outer container, the inner bag is detached from the wall of the outer container and is again applied to it, wherein holes are formed in the wall of the outer container at diametrically opposed positions, which lie on the intersection line of a plane defined by the base seam and the longitudinal axis of the container with the container wall and that a pin-shaped tool forces the inner bag through the holes by a predetermined distance from the wall of the outer container and thereby detaches it from the wall, whereafter a pressure medium is introduced through the holes into the gap between the inner bag and the outer container, which detaches the inner bag from the wall of the outer container.

2. A method as claimed in claim 1, wherein the container has a bottle shape, wherein the holes are formed in the shoulder region or closely below it.

3. A method as claimed in claim 1, wherein the holes are formed by a circular cutter.

4. A method as claimed in claim 1, wherein the holes are formed by a rotating tubular knife.

5. A method as claimed in claim 1, wherein the pressure medium is compressed air that is introduced through the pin-shaped tool.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0019] FIG. 1A shows a perspective view of a container having holes;

[0020] FIG. 1B shows a side elevation view of the container having holes;

[0021] FIG. 10 shows a top view of the container having holes;

[0022] FIG. 1D shows a vertical section view of the container along line A-A of FIG. 10;

[0023] FIG. 2 shows the container with a stamping pin for detaching the inner bag from the wall of the outer container.

DETAILED DESCRIPTION OF THE INVENTION

[0024] The container 1 illustrated in the figures includes a neck region 2, which merges via a shoulder region 3 into the broader region 4. The container 1 is a substantially stiff outer container 5 and a readily deformable inner bag 6.

[0025] Situated at the base of the container there is a straight weld seam 7, in which the inner bag 6 is held.

[0026] FIG. 1B shows a side view of the container 5 having a hole 8, which passes through the wall of the outer container 5 and is situated in the vertical plane, which extends through the welded base seam 7 and the central longitudinal axis of the container 1. FIGS. 10 and 1D show that two holes 8 are formed diametrically opposite to one another in the wall of the outer container 6 and that the two holes 8 are not offset in the peripheral direction with respect to this plane, as is the case in the prior art.

[0027] The two holes 8 are situated in the transition region of the broad portion 4 of the container 1 to its shoulder region 3.

[0028] It may also be seen in the figures that the holes 8 are not formed by a boring tool but by a circular cutter, as is preferred.

[0029] FIG. 2 shows a device 9 with a stamp pin 10, which presses the inner bag through a predetermined distance into the interior of the container 1 through the hole 8 in order to detach the inner bag 6 in the surrounding region from the wall of the outer container 5, whereafter the detaching process is continued either by the device 9 or another device by blowing in compressed air. FIG. 2 shows, in the right-hand portion, a device 9 with a retracted stamp pin 10.