The invention concerns a container closing unit, intended particularly for beverage containers, which ensures non-detachable, stable connection between the container and the lid.

In order to achieve the appropriate shelf life of food products packed in containers with a lid, it is necessary to achieve a leak-proof and air-tight connection. The requirement is particularly difficult to meet in the case of e.g. beverage products, pressurized beverages in particular. The commonly- applied method to meet the above requirement is the use of an additional material demonstrating the sealing properties in the area of connection between the container and its lid in the process of thermoplastic moulding of the container and the lid. It must be emphasized, however, that the sealing material may only serve its role if the lid and the container, once connected to each other, do not deform because of the pressure inside the container and/or damages in the assembly process, where the deformations would cause changes to the connection in itself, the said changes consisting in the formation of slits between the sealing material and the lid, and/or between the sealing material and the container, or in total destruction of the connection between the container and the lid, which irreparably eliminates the leak-proof and air-tight properties in the area of connection, and this in turn irreparably devoids the container of the features indispensable for storing the product inside and keeping its proper shelf life.

Disclosed in patent document US 4,487,326 A is a plastic container closed with a lid of flexible plastic, indented for pressurised beverages. The lid has a convex surface facing the inside of the container, having a rim incorporating an annular axial wall, a radial wall, and a peripheral wall which engages on the container edge wall. In addition, the lid has a sealing surface. Known from patent document US 4,640,435 A is a plastic can for carbonated beverages, which includes a plastic lid snapping onto the can. The can includes a neck portion ended with an outwardly extending locking flange having the shape of reversed letter V in cross section. The lid includes a concave top wall which fits into the can mouth, and a peripheral rim extending outwardly and downwards, thus forming a downwardly opening locking groove having the shape of reversed letter V in cross section.

The purpose of the invention is to develop a configuration of the set of technical geometrical features of a container closing unit, which will ensure irreversible stability of connection between the container and the lid and protect the area of connection against deformation, cracking, ripping off, deflection, or slipping out of the structural elements which make up the closing unit in the container/lid mounting process and when subject to the stress caused by the inner pressure in the container closed with the lid. In particular, the purpose of the invention is to eliminate the formation of slits between the lid and the container, or prevent total destruction of the connection.

A container closing unit, intended particularly for beverage containers, comprising the top part of the container which includes the outer side surface around the container mouth, and a lid which includes the top part covering the container mouth, and the side part including the inner surface, where formed on the said outer side surface around the container mouth and on the said inner surface on the side part of the lid are mutually coupling profile elements, according to the invention is characterised in that the mutually coupling profile elements take the form of at least two pairs of profile elements, where one pair of the profile elements is made up of a projection formed on the inner surface of the side part of the lid and a socket formed on the outer side surface around the container mouth, the socket having a side resistance surface.

Preferably, the outer side surface around the container mouth dilates downwards with respect to the said mouth and includes the top part and the bottom part, where the sockets are formed in the said bottom part.

Preferably, formed in the top part of the outer side surface of the container, above the sockets, are protruding profile elements having the top slanted surface along which the projection is guided with its side surface into the socket in the container closing process, and having the bottom surface against which the top surface of the projection fitted in the socket is pressed once the container has been closed.

Preferably, at least one socket is fitted with a stopper formed along the edge of the side resistance surface of the socket.

Preferably, the pairs of profile elements are positioned opposite each other.

The side part of the lid and the top part of the lid constitute separate elements, where the side part of the lid is given the form of a clamp, and the top part of the lid is given the form of a cap; alternatively, the side part of the lid and the top part of the lid constitute a single, integral element.

The structure of the closing unit according to the invention enables tight, non-detachable connection between a plastic container and a plastic lid, and ensures irreversible stability of the connection between the container and the lid. It ensures protection of the closure area from deformation, cracking, ripping off, deflection, formation of slits, or slipping out of the mutually coupled structural elements in the conditions of high pressure inside the container.

The technical means used in the solution according to the invention are attainable in standard thermoplastic moulding processes, and enable using the existing devices for closing containers with lids. The above eliminates the need to manufacture new production infrastructure and guarantees obtaining high efficiency of the process.

Further benefits and advantages of the present invention will become apparent after a careful reading of the detailed description with appropriate reference to the accompanying drawings.

In the drawings:

Fig. 1 presents the top part of the container, in side view;

Fig. 2 shows the top part of the container, as in Fig 1, in cross section along the X-X line;

Fig. 3 depicts detail A, as in Fig. 2;

Fig. 4 presents the closing unit with a two-part lid, prior to its mounting, in spatial view;

Fig. 5 shows the closing unit as in Fig. 4, with the top part of the lid in place and without the clamp installed;

Fig. 6 depicts the lid in half-section, in orthographic projection from the bottom;

Fig. 7 presents the lid as in Fig. 6, in cross section along the W-W line;

Fig. 8 shows the lid as in Fig 7 in cross section along the Z-Z line;

Fig. 9 depicts the closing unit with the lid in the form of a single element, prior to its mounting, in spatial view;

Fig. 10 shows the closing unit in the position prior to assembly, in cross section along the 0-0 line, as in Fig. 18;

Fig. 11 presents detail B, as in Fig. 10;

Fig. 12 shows the closing unit in the first stage of the assembly process, before pressing, in cross section along the 0-0 line, as in Fig. 18;

Fig. 13 depicts detail C, as in Fig. 12;

Fig. 14 presents the closing unit in the second stage of the assembly process, after the pressing, in cross section along the 0-0 line, as in Fig. 18;

Fig. 15 shows detail D, as in Fig. 14;

Fig. 16 depicts the assembled closing unit in cross section along the R-R line, as in Fig. 18;

Fig. 17 presents detail E, as in Fig. 16;

Fig. 18 shows the closing unit, as in Fig. 16, in cross section along the X-X line;

Fig. 19 depicts the closing unit in cross section along the R-R line, as in Fig. 18;

Fig. 20 presents the assembled closing unit, with cross-section along the P-P broken line, as in Fig. 18;

Fig. 21 shows the top part of the container with the lid in place, in spatial view.

An exemplaiy embodiment of the closing unit, intended particularly for beverage containers, incorporates the top part of the container including the outer side surface 2 around the container mouth 1 , and a lid including the top part 8 which covers the container mouth 1 and the side part 4 including the inner surface. Formed on the said outer side surface 2 around the container mouth 1 and on the inner surface of the side part 4 of the lid are pairs of mutually coupling profile elements, positioned opposite each other. Each pair of the profile elements is made up of a projection 5 formed on the inner surface of the side part 4 of the lid and a socket 3 formed on the outer side surface 2 around the container mouth 1, the socket having a side resistance surface 3’. The outer side surface 2 around the container mouth 1 dilates downwards with respect to the mouth 1 and includes the top part 2’ and the bottom part 2”, where the said sockets 3 are formed in the bottom part 2”.

In addition, formed in the top part 2’ of the outer side surface 2 of the container, above the sockets 3, are protruding profile elements 6 having the top slanted surface 6’ along which the protrusion 5 is guided into the socket 3 in the container closing process, and having the bottom surface 6”, pressed against which is the top surface 5’ of the protrusion 5 fitted in the socket 3. Some of the sockets 3 are additionally fitted with a stopper 7 formed along the edge of the side resistance surface 3’ of the socket 3.

In one embodiment (Fig. 4, Fig. 5, Fig. 19) the side part 4 of the lid and the top part 8 of the lid constitute separate elements, where the side part 4 of the lid is given the form of a clamp, and the top part 8 of the lid is given the form of a cap.

In another embodiment (Fig. 9 to Fig. 16) the side part 4 of the lid and the top part 8 of the lid constitute a single, integral element.

The method of assembling the container closing unit, in the single element lid variant, is shown on Fig. 10 to Fig. 16.

The side part 4 of the lid is fitted on the outer side surface 2’ of the top part of the container, as shown on Fig.12, Fig. 13 (the first stage of the assembly process). Then, by application of force the protrusions 5 are inserted into the sockets 3 so that the side surface 5’ of the protrusions 5 formed on the inner surface of the side part 4 of the lid slides on the top slanted surface 6’ of the protruding profile 6 formed above the socket 3, so that the projection 5 is guided into the area between two neighbouring sockets 3, as shown on Fig. 14 and Fig. 15 (the second stage of the assembly process), following which, by application of force, the projections 5 are moved to the bottom part 2” of the outer side surface 2, while the side surface 4 of the lid swells, following which the lid is turned until the projections 5 find themselves in the sockets, as shown on Fig. 16 and Fig. 17 (the assembled unit).

The method of assembling the container which features a lid in the two- element variant differs from the assembly procedure described above of the single-element lid in that: first, the top part 8 of the lid is fitted in the mouth 1 of the container, as shown in Fig. 5, following which the side part 4 of the lid in the form of a clamp is fitted on the outer side surface 2’ of the top part of the container, whereupon the same procedure is followed as in the case of the lid in the single-element variant.

In the assembled unit, the top surface 5” of the projection 5 formed on the inner surface of the side part 4 of the lid is pressed against the bottom surface 6” of the protruding profile element 6 formed on the top part of the outer side surface 2 around the mouth 1 of the container, and the side surface 5’ of the said projection 5 is pressed against the side resistance surface 3’ of the socket 3 in which the said projection 5 is inserted.

The stoppers 7 formed along the edge of the side resistance surface 3’ of the socket 3 prevent excessive shifting of the lid in the process of closing the container.

The top part of the lid is fitted with any desired technical means to open the container (not shown on the drawing) to enable its emptying.

List of numerical references:

1 - container mouth

2 - outer side surface around the container mouth

2’ - top part of the outer side surface around the container mouth

2” - bottom part of the outer side surface around the container mouth

3 - socket

3’ - side resistance surface of the socket

4 - side part of the lid

5 - projection formed on the inner surface of the side part of the lid

5’ - side surface of the projection

5” - bottom surface of the projection

6 - protruding profile element formed on the top part of the outer side surface around the container mouth

6’ - top surface of the protruding profile element

6” - bottom surface of the protruding profile element

7 - stopper formed along the side edge of the resistance surface of the socket

8 - top part of the lid