US20090223988A1

US20090223988A1 - Can comprising metal or plastic

Info

Publication number: US20090223988A1
Application number: US12/323,697
Authority: US
Inventors: Artur Wichowski
Original assignee: Hoffmann Neopac AG
Current assignee: Hoffmann Neopac AG
Priority date: 2008-03-10
Filing date: 2008-11-26
Publication date: 2009-09-10

Abstract

A can (1) made from metal or plastic including a cap (5) with an annular sealing element (25). A sealing lip (29) is formed on the sealing element that is essentially aligned radially outwardly. The lip contacts an apex (S) of the upper rim of the container (3) when the cap (5) is put on and twisted tight. In case of an overpressure inside the can (1), gas can exit by lifting the sealing lip (29). In case of a higher exterior pressure p₀, the sealing lip (29) is pressed with greater force against the container (3) and prevents the entry of any air.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of Swiss Patent Application no. 00345/08, filed Mar. 10, 2008, and Swiss Patent application 01649/08, filed Oct. 17, 2008, which are incorporated herein by reference as if fully set forth.

BACKGROUND

The invention relates to a can comprising metal or plastic, and in particular to a container and a cap, which can be connected to the container in a sealing fashion and that can be resealed for a partial removal of the material in the container.
It is known to seal containers with a screw-type cap in an air-tight manner. In order to achieve such tightness the cap is provided with an annular seal, usually comprising injected rubber. Such seals fulfill their purpose and the can may be opened for removing any fill material located therein and subsequently be resealed in an air-tight manner. In order to ensure the tightness of the cans even during an extended shelf life prior to the sale and/or prior to any initial opening, additionally a membrane made from aluminum may be applied in a sealing fashion over the opening of the container part.
For storing products, for example smokeless tobacco, such cans are not suitable because the continued fermenting of the tobacco inside the can leads to pressure developing, which causes bulges, deformations, and/or, in the worst case scenario, an explosion of the can. A plastic deformation of the can leads to the sealing no longer being ensured and thus oxygen entering the inside, i.e. to the fill material located therein, may not be prevented. The fill material may dry out due to the oxygen entered in and, in the worst case scenario, it may spoil.

SUMMARY

The object of the invention is to provide a can for protecting the fill material before and after the initial partial removal of fill material from any oxygen entering, however, in case of pressure developing by fermentation or an increase in volume of the air within the can due to heat, allowing an exhalation of gas from the interior of the can into the environment and after the exhalation to securely prevent oxygen from the environment from entering, even in case of a temperature-related vacuum in the can.
This object is attained by a can according to the features of the invention. Advantageous embodiments of the can are described in further detail below.
By using an annular sealing element with an axially effective seal and a radially outward aligned sealing lip it is possible to exhale excess pressure from the can and simultaneously also to prevent any exterior air from entering when a vacuum develops inside the can. By a suitable embodiment and sizing of the threading, the pressure of the exhalation can be adjusted. The very elastic, axially effective sealing element retains its features even after several opening and closing processes of the can.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is explained in greater detail based on an illustrated exemplary embodiment. Shown are:

FIG. 1 is a view of a can, with the left half being in axial cross-section, and the right half in a side view,

FIG. 2 is a side view of the cap for the can,

FIG. 3 is a side view of the container part,

FIG. 4 is an axial partial cross-sectional view through the can with the cap being placed on it,

FIG. 5 is an axial cross-sectional view through a can in an other embodiment of the invention,

FIG. 6 is a side view of the can in FIG. 5,

FIG. 7 is an enlarged view of the edge region of the can in a cross-section (indicated at A in FIG. 5),

FIG. 8 is an axial cross-sectional view through a can in another embodiment of the invention,

FIG. 9 is a side view of the can in FIG. 8, and

FIG. 10 is an enlarged view of the edge region of the can in a cross-section (indicated at B in FIG. 8.)

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In the figures, the reference character 1 marks a can. It comprises a can bottom, called container 3 for short, as well as a cap 5. The container 3, cylindrical in the example, is reduced in the area of its upper edge 7, i.e. the diameter of the container 3 is smaller in the area of the upper edge 7 than in the lower section. A step 9 or a shoulder develops between the reduced area and the lower part. The upper edge of the container 3 is formed with a rolled rim 11. This means, the edge is shared approximately oval in its cross-section by a forming process
The cap 5 comprises a cap surface 13, which covers the opening of the container 3. A cylindrically extending collar 15 is provided on the cap 5, in which snapping cams or threads 17 are embodied by way of plastic deformation. This free edge 10 of the collar 15 is preferably folded over to place the edge region, which may show a sharp edge by the cutting process, out of the contact area when opening the cap 5. The snapping cams or threads 17 on the collar 15 engage the snapping protrusions or threaded sections 21 at the reduced area of the container 1 (compare FIG. 4.).
A sealing element 25 is inserted into the circumferential bead 23 in the peripheral section of the cap surface. It comprises a support body 27, which more or less fills the bead 25, as well as the sealing lip 29 extending from it. The root of the sealing lip 29 is located in the area of the smallest diameter of the annularly shaped support body 27. The free edge 31 of the sealing lip 29 is essentially aligned radially outwardly. The relaxed sealing element 25 has an axial height h₁. The completely axially compressed sealing element 25 (not shown) has an axial height h₂. For the axially completely compressed sealing element 25, the sealing lip 29 contacts the support body 27. In a cap 5, loosely placed onto the container 1 according to FIG. 4, the distance between the bottom of the cap surface 13 and the apex S at the rolled rim 11 is equivalent to the height h₁of the relaxed sealing element 5. In this position the free edge 31 of the sealing lip 29 essentially contacts the apex S of the rolled rim 11 without any pressure.
In order to close the container 3, the cap 5 is axially pulled downward by way of turning threads, i.e. the cooperating snapping cams or threads 17 and the snapping protrusions or thread sections 21 or by an axial compression of the cap 5 over the snapping protrusions or threads 21. Here, the sealing element 25 and/or the sealing lip 29 is pressed against the apex S of the rolled rim 11. In order to achieve optimal sealing, the distance s between the bottom free edge 19 at the collar 15 of the cap 5 and the step 9 at the container 1 is defined such that the free edge 31 of the sealing lip 29 is pressed against the apex S with a precisely defined force.
The sealing lip 29, bent radially outwardly when viewed in the cross-section, is only axially stressed by the compression force of the cap 5 when there is no pressure difference between the atmospheric pressure p₀and the interior pressure p₁. A gas exchange between the interior of the can and the atmosphere does not occur. When the interior pressure is elevated, e.g., by the material filled in fermenting or by an increase in volume due to rising temperatures, gas can exit to the outside between the apex S of the rolled rim 11 at the container 3, because the sealing lip 29 is raised by the higher pressure acting inside. An exterior pressure p₀elevated in reference to the interior pressure p₁however causes an increased pressure of the sealing lip 29 against the apex S, because the sealing lip 29 cannot deflect. This ensures that in case of an increased interior pressure p₁any bulging of the cap surface 13 can be avoided.
The can 1 according to the invention can be produced from metal or plastic. Combinations of a metal can 3 with a cap 5 made from plastic are also possible.
The sealing element 25 can be inserted loosely into the bead 23 or be mounted thereto using an adhesive.
In the embodiment of the invention according to FIGS. 5 through 7, the sealing element 25 is no longer inserted into the lid 5 but represents a part of the interior container 33, which is inserted into the exterior can 1. The interior container 33 can alternatively also comprise only an insertion part essentially shaped like a cylindrical jacket, not provided with a bottom but being supported on the bottom of the container 3 (not shown.) The sealing element 25 is embodied in the upper section of the interior container. It comprises the sealing lip 29 aligned radially outward and contacting the surface of the lid.
The interior container 33 can simultaneously act as the connection between the container 3 and the lid 5. For this purpose, an encircling groove or a recess 37 can be formed at the periphery of the interior container 33. A first rolled bead 29 engages said recess and a second rolled bead 41 the lid 5.
In another embodiment of the invention according to FIGS. 8 through 10 the container 3 is made from plastic. At its upper edge 43 the sealing element 25 is fastened to the sealing lip 29 by suitable means. In the example shown, in the upper edge 43, a groove 45 is shown expanding towards the bottom, which is engaged by a respective rib 47 at the sealing element 25 and is snapped in place. By this embodiment the chance develops to produce the container 3 comprising a plastic which is harder than the plastic that the sealing element 25 is made of. Alternatively, the container 3 or the interior container 33 with the sealing element 25 are produced in a 2K-injection molding process so that a subsequent assembly of sealing element 25 and a container 3 is omitted.
In this embodiment of the invention, the lid 5 snaps in place below a bead 49 at the periphery of the container 3 made from plastic.

LEGEND

1 can
3 container
5 cap
7 upper edge
9 step
11 rolled rim
13 cap surface
15 collar
17 snapping cams or threads
19 free edge
21 snapping protrusions or thread sections
23 bead
25 sealing element
27 support body
29 sealing lip
31 free edge
33 interior container
35 sealing edge
37 recess
39 first rolled bead
41 second rolled bead
43 upper edge of 3
45 groove
47 rib
49 bead

Claims

1. A can made from metal or plastic, comprising a container (3) and a cap (5), which can be connected to the container (3) in a sealing manner and also in a resealing manner for a partial removal of the fill material in an interior of the container, a sealing element (25) located between the cap (5) and an upper edge (7) the container (3, 33), allowing gas to exit the container (3) in case of an increased interior pressure p₁, and that, in case of an increased exterior pressure p₀, blocks entry of oxygen into the interior of the container.

2. A can according to claim 1, wherein the sealing element comprises a seal with an axially effective lip (29).

3. A can according to claim 2, wherein the sealing element (25) is arranged in the cap (5), on the container (3), or on an interior container (33).

4. A can according to claim 2, wherein a free edge (31) of the lip (29) is essentially aligned radially outwardly.

5. A can according to claim 2, wherein a support body (27) at the sealing element (25) is inserted and held and/or adhered in a circumferential bead (23) in the cap (5).

6. A can according to claim 3, wherein the sealing element (25) is assembled on the interior container (33) or produced together therewith by an injection molding process.

7. A can according to claim 2, wherein the cap (5) and the container (3) can be snapped to each other via a snapping connection (17, 21) and the snapping connection is formed by snapping cams (17) on the lid (5) and snapping protrusions (21) on the container (3).

8. A can according to claim 6, wherein the cap (5) can be snapped in place at an encircling recess (37) on the interior container (33).

9. A can according to claim 7, wherein the snapping connection is formed by threads (17) and thread sections (21) suitably embodied on a collar (15) of the cap (5) and on the container (3).

10. A can according to claim 6, wherein the snapping connection (17, 21) is embodied such that the lip (29) of the sealing element (25) is pressed against the cap (5) with a force, which allows gas to exit the container (3) at a defined pressure.

11. A can according to claim 10, wherein in an engaged position in which the cap (5) is snapped in place, a lower edge of the collar (15) of the cap (5) contacts a step (9) at the container (3) such that a defined axial distance is provided between a the recess (23) in the cap (5) accepting the sealing element (25) and the upper edge of the container (3) which is smaller than an axial height h₁of the sealing element (25) in a relaxed state and greater than a minimum axial height h₂of the sealing element (25) in a compressed state.