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United States Patent 
[ii] 4,197,949  Apr. 15,1980
 OPENING OF CONTAINERS
 Inventor: Lars C. Carlsson, Blentarp, Sweden
 Assignee: Tetra Pak International AB, Lund, Sweden
 Appl. No.: 937,172
 Filed: Aug. 28,1978
 Foreign Application Priority Data
Sep. 1, 1977 [GB] United Kingdom 36642/77
 Int. C1.2 B65D 5/54; B65D 5/72
 U.S. CI 206/611; 206/625;
206/626; 206/628; 229/17 R
 Field of Search 229/7 R, 17 R, 7 S,
229/176; 206/626, 610, 611, 628, 607, 625
 References Cited
U.S. PATENT DOCUMENTS
2,288,914 7/1942 Monroe 229/17 G
2,750,093 6/1956 Moore 229/17 R
2,801,040 7/1957 Meyer-Jagenberg et al 229/7 R
2,964,226 12/1960 Nerenberg 229/17 R
3,353,738 11/1967 Andreasson 229/7 R
3,613,986 10/1971 Christensson 229/17 R
3,940,054 2/1976 Goebel et al 229/7 R
4,101,051 7/1978 Reil 229/7 R
4,113,103 9/1978 Carlsson 206/630
4,126,263 11/1978 Mortensson 229/17 R
FOREIGN PATENT DOCUMENTS
2357431 3/1978 France .
1472157 5/1977 United Kingdom .
Primary Examiner—Stephen P. Garbe
Attorney, Agent, or Firm—Burns, Doane, Swecker &
Containers made of flexible material often have opening arrangements in the form of a tear strip for opening an outlet aperture. The tear strip constitutes a part of the container wall and is limited by a weakening line. To facilitate initiation of the tear-open operation a short length of the weakened line has the form of a cut or cuts extending fully through the material. Two or more cuts may form a lug or projection, and if located at a fold line of the container blank the lug or projection may be arranged to automatically extend outwards from the finished container.
7 Claims, 5 Drawing Figures
U.S. Patent Apr. 15, 1980 Sheet 1 of 2 4,197,949
U.S. Patent Apr. 15, i98Q sheet 2 of 2 4,197,949
OPENING OF CONTAINERS
This invention relates to the opening of packaging containers, and more especially containers formed from flexible laminate packaging material. It may be regarded as an improvement in, or modification of, the invention disclosed in the specification of British Patent Application No. 26540/77, where there is described a container having a tear-strip for opening an outlet aperture closed by an inner cover strip bonded over part of its area to the tear-strip.
The present invention consists of a container provided with a weakened line defining an area adapted to be torn open in order to provide an outlet aperture, said openable area being masked by an internal plastics seal, with said tear-open area being bonded to said internal plastics seal so that when the said area of the container is torn open it tears away with it only part of the corresponding area of the said plastics seal, and wherein a short length of said weakened line comprises a cut or cuts extending fully through the material forming the container, but not through the internal plastics seal by which the defined area is masked, in order to facilitate initiation of the tear-open operation.
The weakened line may conveniently be a line of perforations defining a strip of suitable shape in the packaging material forming the container, and since, with such a tear-strip it is not easy for a user to separate a short length of the edge of the tear-strip from the adjacent surrounding material in order to initiate opening of the container, the short length of the weakened line which is cut fully through, (but leaving the inner masking seal uncut, so that the contents remain fully sealed in the container) overcomes the difficulty. Two or more short cuts may provide a lug or projection from the edge of the tear-strip for ready grip to initiate opening of the container. This lug or projection may be located at a fold-line of the container blank, so that when the blank is folded into an erected container the lug or projection extends outwards from a fold of the blank.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will be clearly understood from the following description of one form which it may assume, and this description will be more readily understood by reference to the accompanying drawings wherein
FIG. 1 represents part of a blank of packaging material from which a container in accordance with the invention may be formed:
FIGS. 2 and 3 represent in perspective part of a container formed from a blank such as shown in FIG. 1;
FIG. 4 represents in perspective the container shown in FIG. 3 after the outlet aperture has been exposed; and
FIG. S presents an inside-surface view of part of the blank shown in FIG. 1.
DETAILED DESCRIPTION OF THE
In order to form the container of this invention, a blank of packaging material having an outer layer of paper or cardboard bonded to an inner layer of plastics material is provided, which is, of course, liquid-proof if the container is to hold liquid. The packaging material may, if desired, incorporate other laminate layers, e.g. an outer plastics layer and/or one or more additional inner layers of plastics or metal foil. The blank is pre
formed with crease-lines or fold-lines to facilitate folding into parallelepipedic shape when a container is being formed therefrom. The blank may be part of a web of packaging material adapted to be formed into a
5 tube by seaming together opposite longitudinal edges, whereafter the tube is filled with the desired contents, e.g. milk, formed, by transverse sealing at spaced zones and by shaping, into a plurality of interconnected packaged containers which are separated by severance along
10 the said sealing zones. Such a method of filling, forming, sealing and separating packages is fully disclosed in British Patent Specifications Nos. 1012867 and 1462956.
FIG. 1 depicts an outside view of that part of a web of packaging material which will become the upper end
15 of a package made in accordance with the aforesaid procedure. When the web is folded about the line a b the opposite areas and edges of the web (cut-off from the view shown in FIG. 1) are brought together, and the opposite edges sealed together in overlapping rela
20 tionship, so that the web can thus be formed into a tube which is loaded with the desired contents e.g. milk. It will be noted that when the web is folded about the line a b transverse strips a c and a d come together at their inner faces, and after the tube is loaded an individual
25 package is defined by heat-sealing together the internal surfaces of these strips cad, and e b f. The packages are separated by severance along the sealing zones. The container can be formed into parallelepipedic shape by suitable relative folding of the panels defined by the
30 fold-lines or crease-lines of the blank. The figures depict an end panel 1, a front-wall panel 2 and rear-wall panel 3, and opposite side wall panels 4, 5 each formed with a sealing fin folded flat against the panel. It will be noted that when the half-panels 4 or 5 forming the side-walls
35 of the container are folded down and into the position shown in FIGS. 2 and 3, the right-angled triangular portions 6 of the panels at the ends of the top panel 1 fold under the middle isosceles-triangular portion 7 of the same panel to form outwardly projecting triangular
40 lugs (FIG. 2) which, in the finished package, are folded down against and bonded to the side-walls 4 (FIG. 3).
To facilitate the opening of a filled package, such as described, there is provided a tear-strip adapted, upon finger-manipulation, to open an outlet aperture. This
45 tear-strip is defined by a weakening line, e.g. a line of perforations in the top panel of the package. This line may comprise two substantially parallel leg portions 8 in the top panel 1 running to a loop 9 in the portion 7 of the triangular lug. The perforations may penetrate the
50 panel 1, and also the layers of the triangular lug and the side-wall 5 to which it is bonded so that when the loop portion of the tear-strip is raised from its surroundings, and pulled upwards to tear open the strip along the perforation lines 8, a substantial aperture in the wall of
55 the package is opened. To prevent escape of the contents of the package through this large aperture a masking seal 10 of plastics material is bonded to the inner surface of the container over and around the aperture (FIG. 5). In order to ensure that an outlet aperture for
60 the contents of the package will be formed when the time strip is lifted, the inner surface of the tear-strip is bonded to the masking seal 10 over a selected area between the legs 8 of the lines of perforations. This area is preferably a tongue-shaped area 11 (FIG. S). All other
65 inside areas of the tear-strip are kept free from bonding (e.g. by an inhibiting agent) to the masking seal 10. In consequence, as will be seen from FIG. 5, when the tear-strip is released and lifted it tears away the tongue