NO154225B - INSERTABLE PRESSURE SUBMISSION SENDING CLOSER. - Google Patents

Description

The present invention relates to closing devices which are

easy to open, and more specifically an impressionable pressure release

end closure device in a container element which is suitable for liquids under pressure, comprising a closure element formed in one piece from a part of the container element and defined by at least one weakening line and dimensioned to be able to be opened by a finger-actuated force against the action of the pressure, the closure element having a working part which is adapted to be subjected to the impacting force in use and a connection to the beolder element.

It is generally accepted in box manufacturing that a box

which have impression closures, require, for highly carbonated beverages, some form of pressure release venting closure device by means of which the pressure in the can can at least be reduced prior to the opening of the pouring closure device. An example of a pressure release vent closure device is shown in fig. 1 in the attached drawings where you will see that the ventilation closing device V is smaller in area than the full closing device P.

Cans containing highly carbonated beverages, including those having vent closure devices as shown in fig. 1, tend to gush or splash when opened, particularly where the drink in the can tends to foam.

The problem is compounded when the can is poured during the opening operation as this often means that the liquid in the can is close to or covers the vent closure device, whereby the escaping gas has an easier time mixing with some of the liquid or foam in the can. The problem is further compounded when the can is handled carelessly prior to opening it, as shaking causes the release of carbon dioxide in the can's headspace and thereby generates foam.

US patent 2 2 61 117 deals with an impression closing device comprising a single closing element. The closure member is formed by forming a bulge in the container member, separating around the bulge to form a separate bulged tab, and then flattening the bulged tab to place the cut edges thereof and the outer portions surrounding the opening in an overlapping relationship.

US patent 3,334,775 deals with a box lid fitted with a gate, where the gate can be pressed down into the container by finger-actuated impression force. The container has a simple gate, but there is described in column 4, lines 62 - 66 of the said patent a device where a part of the gate panel can be folded inwards from each end to provide a special pouring part and a venting part, where the section of the gate panel between these parties remain in position. The aforementioned patent neither deals with nor suggests a resealable ventilation element.

US Patent No. 3,741,432 and Australian Patent No. 475,951 each disclose a closure tab for a container, with a pressure release tab formed in the closure tab. Manual pressure applied to the pressure release vent tab is transferred to the closure tab. Both the release vent tab and the closure tab can be depressed by the pressure of the user's thumb applied to the release vent closure tab and transferred to the closure tab in a single operation that first exposes the release vent and then the closure vent or opening. The said patent does not contain any suggestion that the pressure release venting tab referred to therein can be resealed by releasing the finger-generated impression force. In fact, the entire pressure force in said patent is present to allow the pressure to be vented and the hatch to be opened in one operation without withdrawing a finger from the tab area.

US Patent Nos. 3,759,206 (re. 28,910) and 3,931,909 relate to impressionable closure devices that are easy to open and intended for containers such as metal beverage cans.

The patents deal with the formation of closing devices which are

ease of opening by hollowing out an area of a box end, or

another container member, and cutting a tab from the container member, with at least one portion of the recess located outside and surrounding the tab. After the separation or cutting operation, the recess surrounding the opening is flattened to displace the metal in overlapping relationship with the cut edges of the tab.

US patent 3,958,717 deals with an impressionable closing device

which is easy to open and which includes a pouring flap and a ventilation flap. The tabs are joined together with the box lid at a hinge area and share a common hinge area, with the tabs extending in the opposite direction from the common hinge area. It is further stated that this construction results in a performance similar to a conventional ring-pull end, so that special instructions will not be required to teach the consumer, and also with the tabs located directly adjacent to each other, the box can be opened with a minimum of finger movement. There is no suggestion that the ventilation flap seals itself again when the finger pressure applied to it is removed.

US patent 4,033,275 relates to a can for drinks, where the end of the can has a venting tab and a pouring tab, largely corresponding to the construction in US patent 3,958,717, except that the tabs do not share a common hinge area, but are instead described to be located distant from each other.

It is thus an object of the present invention to provide improved objects for pressure-triggering closing devices by means of which outflow or splash problems as described above are at least avoided or made more controllable.

The present invention provides an impressionable pressure-triggered closing device in a container element, of the type indicated at the outset, and the new and characteristic feature of the invention is that the closing element and the part of the container element that surrounds the closing element comprise means to essentially prevent permanent opening of the closing element at an unlimited finger-actuated retraction force, whereby the closing element essentially returns to its closed position in the absence of the finger-actuated retraction force

the force to such an extent that the discharge of foam and/or liquid under pressure from the inside of the container is prevented.

It will be understood from the above that since the closure element does not remain open except when the indentation force is applied to the operative portion, outflow or spatter will not be allowed to continue when the force is removed. Furthermore, since the indentation force must be applied to hold the closure open, the finger or thumb applying the force will act to deflect any liquid or gas coming from the closure.

In the previous devices shown in fig. 1, is the tendency for the person who opens the closure device to remove his finger from the closure device before the spraying begins, which makes,

in extreme situations, the splashing liquid can easily form a waterfall.

The present pressure release closing device can be provided in several ways. E.g. the degree to which the working part is raised and/or the effective area of the pressure release closure element available for activation can be chosen so as to prevent deflection of a finger-actuated force beyond the angle at which the elastic limit of the metal at said connection is exceeded, thereby preventing permanent opening of the closing element by finger or thumb pressure. Alternatively, the connection can be arranged at a remote position relative to the operating part compared to the previously known devices, where the hinge is close to the periphery of the operating part,

and the closure element cannot be opened sufficiently to deform beyond its elastic limit the metal defining the connection. In a particularly preferred form of the invention, the pressure release closure device is formed at the narrow end of a largely pear-shaped pour closure device hinged end to end around its wide end, said pressure release closure device being partially separated from said pour closure device apart from a narrow connection about which the pressure release closing device bends under the pressure release opening thereof, as mentioned

pressure release closing device is preferably raised to such an extent or of such an effective size that permanent opening of this is prevented by finger or thumb pressure.

In the case of the devices shown in fig. 1, it is likely that the thumb or finger will cover the hole created by opening the vent closure device. It has been found that this results in undesirable opening characteristics being introduced by the user as the tendency is for the user to remove the thumb or finger as soon as gas emissions are detected. With the preferred device described above, the release of gas can occur as soon as the closure device is opened while the release of splashing liquid can be prevented by triggering the opening force on the closure element, and controlled emissions are achieved by releasing the gas and/or foam in short bursts.

In another preferred form of the invention, the pressure release closure element is formed as an extension of a pouring closure device, with the opening closed by respective closure devices preferably interconnected to form a single opening. In this arrangement, the pressure release closure device operates in the manner described above, but is removed from its opening when the pouring closure device is opened, thereby providing a ventilation opening by means of which the contents of the box can be vented during the pouring operation.

In another preferred embodiment of the present invention, the operating part is placed at one end of a relatively narrow elongated part which extends from the connection to the container element. With this device, it is unlikely that the finger or thumb applying the opening force will completely cover the entire closure device, which thus provides an escape path for the gases released from the container.

For all embodiments of the present invention,

is it critical that the closing device is not pressed down in the opening with which the closing device is connected to an extent that exceeds the elastic limit for this. By causing the closure device to be pressed down into the beverage can or other container by applying finger-actuated impression force on

this, with bending of the closing device about the connection,

without exceeding the elastic limit of the connection, the closing device will return at least substantially to its original position, thereby resealing the container against further discharge of foam or liquid from it. The internal pressure in the container helps to reseal the closure.

The exact amount of compression to which a given fastener can be subjected without the elastic limit of its connection being exceeded will depend on a number of variables, such as the size of the fastener, the thickness of the metal, the type of metal, the effective length of the connection,

and such. In general, it is not possible to specify an exact amount of the angular deflection of the closing device to which it can be subjected before the elastic limit of the connection is exceeded. In general terms, however, the amount of angular depression of the closing device can be more easily understood from an assessment of the subsequent simulated test.

A closure was formed in a sheet of 5082 aluminum having a thickness of 0.0381 cm. The closing device was of the construction shown in fig. 6, with the central cut located 0.0464 cm from the center of the closure. The free or cut edges of the sides in the closing device were located approx. 0.0381 cm from the center of the closure device. The end of the closure farthest from the connection was bent in the simulated box a distance of 0.0762 cm, corresponding to an angular deflection of 5.5°, and on removal of the deflecting pressure the closure returned to approximately its original position. A deflection of 0.0889 cm still resulted in the return of the closure to approximately its original position, ie the elastic limit of the connection was not exceeded. When depressing the closing device a distance of 0.1016 cm corresponding to an angular deflection of 7.5°, permanent deformation of the connection occurred,

and the closure would not return to its original position.

This simulated test was performed by clamping the closure at the hinge line, with the application of force placed on the free edge of the closure furthest from the hinge line.

Based on the results of this test, it appears that the angular displacement of the closure must be less than 7.5°, and preferably no more than 5.5 - 6°. Of course, the depression must be sufficient to allow release of pressure from the interior of the container, and the minimum deflection that will achieve this result will depend on a number of variables, including the thickness and type of sealant applied to the parting line.

In actual use by the consumer, whose opening habits can vary quite a lot, it may be possible to occasionally achieve some small permanent deformation of the connection or hinge, but this deformation would be unusual (perhaps caused by extremely strong consumer) and should be reduced by the internal pressure in the can, especially when carbonated - or malt-containing drinks are in the can.

In order for the invention to be easier to understand, several preferred embodiments of the invention will now be described with reference to the attached drawings. Fig. 1 is a plan view of a box end according to the known technique. Fig. 2 is a plan view of a single embodiment which demonstrates the principle of operation for this compared to the previously known end. Fig. 3 is a plan view of a preferred practical realization of the invention. Fig. 4 is an enlarged fragmentary sectional vertical view of the end in Fig. 3, along the line 4-4 in fig. 3. Fig. 5 is a schematic fragmented sectional vertical view of press piston components which are appropriate for the formation of the closure device as shown in fig. 3 and 4. Fig. 6 is a plan view of a modified form of the embodiment in fig. 3. Fig. 7 is a plan view of another preferred embodiment of the invention. Fig. 8 is an enlarged fragmentary sectional vertical view along the line 8-8 in Fig. 7. Fig. 9 is a plan view of yet another form of the invention.

Fig. 10 is an enlarged sectional vertical view along the line 10-10

in fig. 9.

Fig. 11 is a fragmented plan view of a modification of the embodiment in fig. 9. Fig. 12 is a schematic representation of one of the steps in the formation of the closing device in fig. 9 and 10. Fig. 13 is a schematic view corresponding to that in fig. 12 which shows a modified formation method. Fig. 14 is a plan view of yet another preferred embodiment of the invention. Fig. 15 is a sectional vertical view along the line 15-15 in fig. 14. Fig. 16 is a fragmented sectional vertical view of the closing device in fig. 12 and 13 formed in a depressed area in a flat end panel. Fig. 17 is a plan view of yet another further embodiment of the invention. Fig. 18 and 19 are enlarged sectional vertical views along the line 18-18 in Fig. 17. Figs. 20, 21 and 22 are fragmentary plan views of modifications of the embodiment in fig. 17.

In fig. 1 in the drawings has previously known box ends as

shown in fig. 1 a pressure release/vent closure device V and a pour closure device P. Each closure device is circular and is hinged together at H to the box end at the periphery of the closure devices. Thus, when the closing devices V and P are opened, they will be hinged around H and as the opening force bends the closing devices at such an angle that the elastic limit of the metal forming the hinge H is exceeded, the closing devices will remain open when they are once open. In the case of the closure device V, the flap thereof will be raised more than the pouring flap to ensure that it can be pushed open to such an extent that sufficient ventilation of the box can occur during pouring.

In the simple or schematic embodiment of the invention which

shown in fig. 2, the ventilation closing device V is replaced by a pressure release closing device 10. The closing device 10 comprises a closing element or a flap 11 which has an operating part 12 in the form of a raised button by means of which an opening force can be pressed on the closing device 10 by means of a finger or thumb . The tab 11 has a relatively elongated narrow design compared to the ventilation closing device V and is connected in one with the end at 13. The connection 13 does not act as a hinge in use in the same way as the hinges H in fig. 1 works, and for this reason the connection is described as a connection rather than as a hinge.

The closing element 11 is of the fully broken construction as described in US patents no. re. 28 910 (3 759 206) and 3 931 909, the description of which is hereby incorporated by reference, and is formed by the method described therein, or by embossing or otherwise expanding the tab and/or by shrinking the size of the opening by any suitable cold working operation such as embossing.

During opening, a force is applied to the upright part 12 by means of a finger or thumb. As the connection 13 is remote from the part 12, it is unlikely that the entire closure device will be covered by the finger and gas discharge openings will be exposed at least along the long sides of the tab 11. Furthermore, the remote location of the connection 13 means that the angle at which the tab 11 can be bent a finger-induced force will not be so great as to exceed the elastic limit of the metal at connection 13, so that the tab will resume at least substantially its closed position on removal of the opening force. This will of course be helped by every pressure inside the box or by escaping contents. These two factors combined mean that when spraying occurs it can be controlled using the closing device 10 by removing the opening force and releasing the gas and/or foam in short bursts.

In practical embodiments, the closure means tend to be located closer to the center of the can end to reduce the likelihood of liquid present in the gas being released from the can. Furthermore, it will be understood that in any commercial embodiment the closure device 10 and P will be hermetically sealed by means of a sealant (not shown), such as plastisol, applied to the ends in any suitable manner.

Despite the aim of the present embodiment to at least reduce the problems associated with its prior art, the device has a practical disadvantage in that the closure device 10, upon release of the impression opening force, no longer acts to ventilate air into the can during the pouring or drinking of liquid from this. However, the problem can be overcome by using any of the closure device embodiments shown in FIG. 3 - 14 in the drawings.

The box end shown in fig. 3 and 4 are formed with a fully split closure element which surrounds a generally pear-shaped opening 21 and is hinged to the end at 22. The tab 20 is formed with a raised area 2 3 extending from the wide end of the tab 20 and a smaller raised area or button 24 adjacent the narrow end of tab 20. The narrow end of tab 20 is partially separated from the remainder of tab 20 along lines 25 and 26, leaving a narrow connection 27 and thereby defining a pressure release tab 28. Button 24 in tab 28 is raised in a greater degree than the area 2 3 so as to be more easily accessible for finger or thumb activation. E.g. tab 28 can be raised approx. 1 mm above the periphery of

tab 20 and you will see from the drawing that tab 20 is level

with the raised periphery of the opening 21.

The parting lines 25, 26 allow the pressure release tab 28 to. is bent about the connection 27 while the height of the tab 28 is selected to prevent permanent deflection after removal of the opening force exerted by a finger or thumb. When the opening force is removed, the tab 28 will close to prevent further spraying in the event that spraying occurs. As soon as the pressure in the box has been released, the closure device 20 can be easily opened by finger pressure applied to the raised area 23 of the flap 20. As in the previous embodiments, sealant (not shown) is applied to cover all dividing lines in the closure device.

It is desirable, both to protect the tabs 20 and 28 against accidental opening, and to stiffen the end against outward bending under pressure, and to form the closing device with a depressed area 29 formed at the end. The depressed area 2 9 can be formed by dome-forming the end panel slightly, e.g. about. 1.5 mm and so

flatten the dome to form the area 29. Alternatively, a flat end panel can be formed with the depressed area 29. In this way, the tabs 20 and 28 are protected by the raised portion 30

in the end panel and the panel is braced against outward deflection.

One will understand from an assessment of the above description

that the embodiment in fig. 3 effectively combines the separate pressure release tab of FIG. 2 and a pouring tab, with tab 20

in itself determining the connection between pressure release

tab 28 and the box end. By effectively joining the pressure release port and tab to the pour port and tab,

the ventilation opening is opened when the tab 2 0 is opened, whereby over-

the problem created by the resealing nature of the pressure release tab 28 is overcome. However, until the tab 20 is opened, the pressure release tab operates in the same manner as described above and therefore avoids the problems associated with the prior art at least to the same extent as the first embodiment.

The construction of the opening 21 results in acceptable pouring and drinking characteristics.

The closing device is formed by a modified version of the method described in the previously mentioned patents. It is not practical under high speed end forming conditions to split the tab 20 and to form the slits 25 and 26 at separate press stations.

Thus, according to another feature of the present invention, a method is provided for forming a closure device tab which has dividing lines which run largely across the dividing line of the tab itself, including dividing the metal along said transverse lines by means of a staggered punch and a spring-biased pressing element which is slidably positioned within the main press element for dividing the tab, said spring-biased press element being pushed into the main press element as the main dividing operation takes place.

During use, the staggered punch will first divide the metal sheet, said transverse lines and partially divide at the adjacent part of the tab. The sliding press element is then pushed into the press, after which the remaining portion of the tab is split.

An apparatus which is suitable for dividing the closing devices is shown schematically in fig. 5 which is a fragmented schematic cross-sectional vertical view of the press components. The press includes a main press element 40 which has a cutting surface 41

in the form of the opening 21, and a pressing element 42 which is slidably mounted in the main press 40 and biased towards the position as shown by means of a spring 43. The sliding element 42

is formed with two cutting surfaces 44, of which only one is shown, for forming the parting lines 25, 26. A staggered punch 45, which has a cutting surface 4 6 corresponding to the cutting surfaces 44, is arranged to first engage the sliding the member 42 to split along the lines 25 and 26 and to split the circumference of the pressure release tab 28. The punch 45 then pushes the sliding member 42 into the press 40, whereupon the punch 45 splits the remaining part of the tab 20 from the end.

The sheet metal that is displaced by splitting along the lines

25, 2 6 is brought back to the same plane as the remaining metal to ensure that the periphery of the flap is all substantially level. If necessary, the metal on one or the other side of each parting line can be embossed to ensure that the slots do not open.

If necessary, the edge of the tab 20 and/or the periphery of the opening 21 can be embossed or otherwise processed to increase the overlap between the tab 20 and the surrounding metal. A modification of the closing device in fig. 3 and 4 are shown in fig. 6. In this modification, the dividing lines 25, 26 are replaced by

a central dividing line 25' providing two separate connections 27' between the pressure release tab 28' and the main tab 20'. The closing device is otherwise identical to the embodiment in fig. 3

and 4 and works in exactly the same way. However, it has the advantage of having an undivided periphery and is more resist-

capable of leaking than the embodiment in fig. 3,

where leakage can occur if the dividing lines 25, 26 are displaced. Furthermore, the undivided periphery of the closure device results

in fig. 6 in a less complicated pressing operation during the production of the closing device. In this case, the central parting line can be formed by a so-called "offset shear" pressing operation.

The closing device in fig. 6 is formed in the following way. The end panel is externally dome-shaped approx. 1.5 mm by a pressing operation or by embossing around the periphery of the end panel adjacent to the recess. The area in which the closure device is formed is flattened and the sheet metal is raised in the region in which the pressure release face 28' is to be formed. The tab 20' is then split and the first bulging operation described in the above-mentioned patents is performed. At the same time, the tab 20' is raised by a form punch and the metal is locally cut off along a line around an edge of the form punch. The bulged metal around the opening is then flattened to form an overlap between the tab and the surrounding metal and sealant is applied along all part lines. If necessary, the metal on either side of said line can be embossed to ensure that the line does not open. Alternatively, the form punch can be provided with a notch so that the aforementioned line is interrupted over a short distance. Of course, instead of cutting along said line, a weakening line, such as an incision line, can form the same function. Once again, the periphery of the tab and/or the metal surrounding the opening can be embossed to increase the overlap between the tab and the surrounding metal.

The box end shown in fig. 7 and 8 are formed with a fully cut closure device comprising a pour closure member or tab 31 hinged to the end at 32 and underlying a pour opening 33, and a pressure release vent closure member or tab 34 attached to the pour flap by means of a uniform neck 35 and continuous radially therefrom to lie below a ventilation opening 36 which opens into the pouring opening 33 above the neck 35. The tabs 31 and 34 are raised upwards with the tab 34 raised to a greater degree so as to be more easily accessible to the finger or thumb. E.g. tab 34 can be raised approx. 1 mm above the periphery of the tab and you will see from the drawing that the tab 31

is level with the raised periphery of the opening 33.

The closure device described above is formed using the same method as with the closure device 10. If necessary, the edge of each tab 31 and 34 and/or the periphery of each opening 33 and 36 can be embossed or otherwise processed to increase the overlap between the tabs and the surrounding metal.

The embodiment in fig. 7 and 8 effectively combine the separate pressure release tab of FIG. 7 and a known pouring tab, with the tab 31 determining the connection between the pressure release tab 34 and the box end. In use, the vent 36 is opened when the pour tab 31 is depressed thereby overcoming the problem created by the resealing nature of the pressure release tab 34. However, until the pour tab 31 is depressed, the pressure release tab operates in the same manner as described above and therefore avoids the problems associated with the prior art,

at least to the same extent as the first embodiment.

In order both to protect the tab 34 against accidental opening and to prevent the ends from bending outwards under pressure, an upright rib R is formed at the end, e.g. in the form shown in fig. 7 and 8.

The design and placement of the rib as it is

shown in the drawings is not essential to the invention, as many other designs and placements of or more ribs or beads can be imagined to be equally effective for the purposes described. It will also be understood that corresponding protective ribs or ribs can be included in the device shown in fig. 2 in the drawings.

The location of the hinge 32 as shown in fig. 7 is also not essential or even necessarily most preferred. The hinge can be placed at the position shown in fig. 3 in the drawings or directly opposite the positions shown in fig. 7.

Correspondingly, the particular design of the combined openings 33 and 36 is not essential to the invention. The smoothly rounded nature of the opening above the neck 35 is preferred for aesthetic and practical reasons and it is considered that the design shown will provide good drinking and pouring properties.

The box end shown in fig. 9 and 10 in the drawings have a

fully cut closure element or tab 50 which overlaps with and underlies the metal surrounding a generally pear-shaped opening 51 and is hinged to the end at 52. The tab 50 has a central area 53 which is raised relative to the periphery of the tab. However, it will be seen that the raised area 53 is at the same general level as the sheet metal that determines the hinge 52, whereby the hinge metal is largely undeformed by the closure device's forming process, which will be defined in more detail below. Tests conducted seem to suggest that an undisturbed nature of the metal at the hinge 52 can easily increase the pressure at which topping, or bulging of the end will occur in this general area of the end.

The tabs 50 have a pressure release closure member or tab 55 formed therein in the manner shown in FIG. 9 and 10 in the drawings. The tab 55 is formed with an upwardly raised button 55 at the end

of a relatively elongated metal area defining the flap. The tabs are hinged to the sheet metal defining the tab 50 at 57 and overlap with and underlie the sheet metal surrounding the slotted opening 58. Both closures are hermetically sealed

sealed by means of a sealant (not shown) and the pressure release closure device operates in the same manner as the pressure release closure devices described in the previous embodiments above. It will be understood, however, that in most opening operations, the two closing devices will be opened by means of a simple one-way impression force applied to the general area of the raised button 56 on the pressure release tab 55. Of course, in situations as described above, it may be necessary to actuate the pressure release closing device several times. However, it should not be necessary for the user to reposition his finger for the final opening operation during which the tab 50 is fully opened. If desired, the tab 55 can be placed in an inverted position adjacent the narrow end of the tabs 50

to ensure that finger repositioning is not required during the opening of the tab 50.

A further modification of the embodiments in fig. 9

is shown in fig. 11. In this closure flap arrangement, the pouring flaps 50' have an oblate shape and are placed in an inverted position with their hinge 52' located near the center of the box end. The pressure release flap 55' is located within a depressed region 54'' of the flap 50' to protect the flap 56', but is otherwise substantially identical to the flap 55'.

The arrangement of the tabs 50' and 55' in this way has that advantage

in placing the tab 55' closer to the center of the box end where the headroom tends to be larger. The box end is formed with a recess 62 which surrounds the closure device 50'. This serves as a sealant well when the sealant is applied to the closure 50' and also allows the sheet metal to be clamped to prevent metal migration when the sheet metal around the opening 51' is embossed to form an overlap.

The above-mentioned embodiments of the invention correspond to the construction of the closing device described in US patent no. 3,741,432 with the exception that the pressure release tab 55 is formed in accordance with the present invention instead of in the manner shown in the US patent. Thus, the closing device shown in fig. 9 and 10 have the same advantages over said US patent as the previous embodiments have over the previously known technique shown in fig. 1. Furthermore, the use of a common hinge area, as shown in fig. 1 and 3 in the said US patent have disadvantages in that depressing the pouring tab 15 causes further depressing of the tab 21 and thereby increases the probability of hinge breakage and detachment of the tab 21 from the box end. It will appear from fig. 9 and 10 in the drawings that the box end incorporating the improved closure device has an outwardly domed central panel 60. Although not readily apparent from the drawings, the dome is somewhat flat on top for a reason to be stated below. The closure device 50 and 55 are formed in a downwardly depressed area 61 which extends into the dome-shaped end from the hinge area 52 in the same general design as the tab 50. The location of the closure device 50 and 55 within the depressed area 61 protects the closure device 50 from accidental activation and in to a lesser extent, the closing device 55 is correspondingly protected against accidental activation. The slight flattening of the dome formed in the end panel 60 increases the height of the dome in the region in which the pressure release tab 55 is to be formed and thereby increases the degree of protection provided to the tab 55 by adjacent areas of the end panel 60.

It will be clear from the cross-sectional vertical diagram in fig. 10 that the top of the button 56 is placed at the same general level as the surrounding sheet metal in the central panel. End panel 6 0

is also preferably dome-shaped for the following reasons. The dome shape of the end panel increases the headroom of a box

to which end it is attached. The dome shape of the end panel also increases the stiffness of the end panel. Finally, it is considered that the doming of the end panel will usefully increase the buckling strength of the reshaped end. In tests carried out on clean ends, it was found that the dome shape of the end panel between approx. 1.5 mm and approx. 3 mm increased bulging strength at the end. Improvements in buckling strength increased as buckling increased.

The closure devices 50 and 52, and 50' and 52', may be formed in a box end blank by any suitable method of penetrating and transforming the sheet metal of the end blank. Under normal circumstances, the process used will involve several separate pressing operations and the punch/press set used will require the usual ejector plates and press ejectors to ensure the separation between the sheet metal and the punch and press components. The use of ejection plates and press ejectors complicates punching/pressing sets and the desirability of reducing the number of pressing operations is clear.

A preferred method for forming the improved closure device will now be described. In a first operation, the end panel is formed with a somewhat flat topped dome. In a second operation, the dome is pushed down to form the area 61

and to form a small depression in the region in which the button 56 is to be formed. The recess is then transformed into the button 56

with a flat top by flattening the top of the recess between two pressing elements. In a fourth operation, the tabs 50 and 55 are cut and in the same operation the periphery of the tab 50 is turned downwards to form the raised area 53. This operation is shown schematically in fig. 12 which is a fragmentary sectional view of the tabs 50 but omitting the tab 55. As noted above, the central portion of the tab remains at the same general level as the unscored metal defining the hinge 52. In a fifth step, the height of the shoulder of the metal is reduced which is defined by the scored portion of the sides of the area 61 and the angle of the side relative to the end panel is increased to produce some overlap between the sheet metal surrounding the opening and the tab 50. Finally, the periphery of the tab is embossed to increase the area of the tab and further increasing the overlap between the tab and the sheet metal surrounding the opening. The sheet metal surrounding the opening 58 is also embossed

to produce overlap between the openings and the pressure release tab 55. The embossing of the periphery of the tab 50 is preferably carried out in a position near the shoulder of the raised area 53 so that most of the metal expansion is in the outward direction instead of back towards the center of the tab. In order to

avoid too much curling at the periphery of the flap during that operation the edge of the flap is firmly held by the pressing elements. Each of the above mentioned operations will be well known to those skilled in the art and are therefore not shown in detail in

the drawings.

It will be understood that in the above description certain of the formation steps have been artificially separated for the purpose of clarifying the invention. In any practical reshaping of the box end, certain of the steps may be combined in a single pressing operation or separated from the steps described above. E.g.

the formation of the recess may need to be carried out in a single step.

The above-mentioned method of forming the improved closure device has several advantages. Firstly, the formation of the closure in the depressed area of the domed central panel provides protection against accidental opening of the closure. Secondly, the downward reshaping of the periphery of the tab 50 enables its central portion to remain at the same level as the hinge 52 and it is believed that this may well improve the pressure characteristics of the reshaped end. This method of forming the tab 50 also allows the pressure release tab 55 to be cut from the tab 50 in the same pressing operation without any undesirable deformation of the tab 50. To form the same type of closure device combination in a flat or upright metal area, the cutting of the tabs can result in a downward turning of the edges of the larger tab which may need to be flattened or restored in a subsequent pressing operation.

Although the above-described method of forming reduces the number of forming steps, it has been discovered that piercing the tabs 50 and 55 can also be combined with the re-forming of the sheet metal surrounding the apertures to form the depressed area 61 surrounding the closure device 50 and forming the button 56. This individual pressing operation is shown schematically in fig. 13 which is a fragmentary cross-sectional view of the punch/press set in the region of tab 50 but excluding tab 55. It will be noted that the punch T is formed with a shoulder and a central depression, while the die D is formed with cooperating shoulders and depressions to enabling the downward recovery of the flap 50 and the surrounding 61.

It has been found that the individual operation of penetration and regeneration not only reduces the number of press stages but also removes the need for ejection plates and press ejectors. The resulting flap and opening are found to be of substantially the same size after the penetration/recovery operation and consequently do not stick in the press or on the punch.

The above method still has the advantage

that the central portion of the tab 50 is maintained at the same general level as the impenetrable metal defining the hinge.

In the second operation, the sheet metal around the periphery of the tabs 50 and 55 and the sheet metal around the opening 51 is embossed to create the necessary overlap between the tabs 50

and 55 and the sheet metal surrounding it. Alternatively, the overlap can be achieved by the methods described in our previous patent application. Following this, sealant is applied in the regions of the cut edges of the tabs 50 and 55 to hermetically seal the two closure devices.

The above method of forming the improved closure device is preferred for several reasons. First, the penetration and recovery operation is performed in one press step, thereby reducing the number of steps and eliminating ejector plates and press ejectors. Secondly, the formation of the closure devices in the depressed area 61 in the central panel provides protection against accidental opening of the closure device. Third, the downward restoration of the periphery of the tab 50 enables its central portion to remain at the same level as the hinge 52

and it is believed that this will easily improve the pressure characteristics of the reshaped end. This method of forming the tab 50 also allows the pressure release tab 55 to be cut from the tab 50 in the same pressing operation without any unwanted deformation of the tab 50. To form the same type of closure device combination in a flat or upright metal area, the cutting of the tabs can result in a downward turning of the edges of the larger lobe, which

may need to be flattened or restored in a subsequent pressing operation.

It will be understood that in the formation of the closure device as shown in fig. 11, the downward restoration of the sheet metal surrounding the tab 55' will be performed in the first pressing operation. This method can also be used to form the modifications to be described below.

It will be understood that other methods of formation can

well applied with equally acceptable results. E.g. the sheet metal surrounding the opening 51 can be embossed to increase the overlap between the tab 50 and the surroundings. Alternatively, the overlap between the tab 50 and the surroundings can only be produced by appropriate restoration of the shoulder as indicated above. The overlap between the pressure release closure device 55 and the surrounding sheet metal is preferably formed as described above as this enables the button 56 to be made larger and placed closer to the periphery of the opening 58. However, the necessary overlap can be produced by embossing the periphery of the tab 55.

It will be understood that the various closure devices

which is described in the previous embodiments can be formed in much the same way as the modified closing device described in the above-mentioned embodiment. E.g. in the embodiments in fig. 3 and 6, the size of the depressed areas can be reduced to the same size as the area 61

and the cantilever surrounding the opening can be flattened as shown in fig.

10. In the case of the embodiments in fig. 7 and 8, the location of the closing device in a depressed area will remove the need to form the protective ribs R.

The embodiment of the invention as shown in fig. 14 and 15

is a modification of the embodiment in fig. 3 and 4 and includes a fully cut closure element or tab 70, corresponding to tab 20 in fig. 3, hinged to the end at 71.

Tab 70 has a pressure release closure element or tab 72 defined by dividing lines 73 and 74 which extend to either side of an upright button 75. Lines 73 and 74 form an intermediate angle of approx. 6 0° even though it has been found that the tab 72 will work very satisfactorily with the lines 73

and 74 forming any intermediate angle within the range of approx. 30° - 180°, and most effective between 50° and 70°.

The tab 72 bends about its connection 76 to the tab 70 on

the same basic way as in the embodiments in fig.

3 and 4, although it will be noted that the angular nature of the parting lines 73 and 74 places the connection 76 further away from the raised button 75 than in the case of the embodiment of FIG. 3 and 4.

For tab dimensions and button height as shown in the drawings,

tab 72 is not capable, during normal operation, of being opened by finger-applied force more than approx. 3° - 5°. This angle range is below the angle at which the metal

in the connection 76 will be permanently deformed so that the tab 72 will, during normal use, always return to the largely closed position as soon as the opening force is removed.

The tab 70 is formed with a depressed area 77 which is formed

in the same basic manner as described above in connection with fig. 9-12. However, the method of forming the pressure release tab 72 is modified to

forming the parting lines 73 and 74. The parting lines 73 and 74 are formed by a staggered punch during an initial step in the springing of the tab 70. In the same initial operation, the remaining part of the tab 72 is also cut and as the punch moves downwards the sides of the tab 70 are restored downwards and the tab 70 divided as described in connection with fig. 12. The free edges of the two tabs 70 and 72 are then brought together so that the two tabs are co-planar at the periphery of the tab. The formation of the parting lines and the downwardly restored nature of the sides of the tab 70 leaves a step of material thickness between the tabs 70 and 72 along the inner portion of the parting lines 73 and 74 (see Fig. 16).

Tabs 70 and 72 are embossed near their free edges to increase the overlap between them and the surrounding metal. The embossing is preferably interrupted at the parting lines 73 and 74 to ensure free opening of these during the bending of the tab 72 about the connection 76.

If desired, the depressed area 77 can be formed in a flat end panel, as shown in the sectional drawing in fig. 16, to achieve

same degree of protection without doming the end panel.

In a similar way, the closure device construction can

which is shown in fig. 3 and 4 are formed using the above-mentioned method instead of the method described in connection with this embodiment or vice versa. However, it is preferred to avoid moving punch components.

It will be understood that the location of the pressure release port and tab radially inward or to the pouring port and tab,

at or near the center of the end, as shown in fig. 3, 6, 7 and 14,

offers the advantage that the pressure release tab is located at the best possible position to reduce the likelihood of the level of the liquid being above the pressure release closure device.

It will also be seen that in each of the above-mentioned embodiments the pressure release tab and the opening are significantly smaller than the ventilation tab at the previously known ends and this results in the tab being significantly easier to open than previously known tabs. The tab V in the previously known box end must act as both a pressure venting tab and an air venting opening and for this reason the tab must either be large enough and/or raised to such an extent that it is capable of being opened permanently sufficiently to perform the second function. It will be understood that if the tab is small it must be raised further to allow access and if the tab is too small there will be insufficient metal available to raise it to the required extent. However, since the tab of the present invention acts only to actuate or release pressure, it is neither necessary nor desirable to raise it enough to be manually depressed to a position in which it ventilates the box during the slope as this is achieved, in said second and third embodiments, when the pouring tab is opened. However, it will be understood that the pressure release tab does not need to be smaller than the tab V in order for the advantage according to the invention to be achieved.

In fig. 17 - 19 a modified form of the pressure release closure device is shown. Once again, the closures are formed with a depressed region in the box end and the general method of forming the end is largely as described above.

The embodiment in fig. 17 - 19 includes a fully cut closure member or tab 80 which overlaps with and underlies the metal surrounding a generally circular pour/vent opening and is hinged to the end at 81. A pressure release closure device or tab 82, of the same type as tab 55 in fig. 9 and 10, is formed partially within the tab 80 and is connected to the end at 83, which connection is located outside the tab 80 and about which the tab 82 bends in the manner described for the previous embodiments. As shown in fig. 18 overlaps the tab 82 and lies below the surrounding sheet metal for the tab 80. In this embodiment, the overlap of the tabs 80 and 82 is increased by embossing the periphery of the tabs and the sheet metal adjacent to the opening closed by the tab 80. The dimensions of the tab 82 are chosen accordingly with the previous application to prevent permanent opening of this by a finger-actuated force.

In use, the tab 82 is opened to relieve the pressure in the box. In most cases, the force exerted by fingers on the tab 82 will also open the tab 80 as soon as the pressure is relieved. However, because tab 82 is located close to the hinge lines

for tab 80, this tab will tend to open in a controllable manner rather than suddenly to avoid accidental injury to the finger from the sides of the opening.

When the closing device 80 is opened as shown in fig. 19 is forced - the closing device 82 to open around its connection 83

and due to separation of the hinge 81 and the connection 83, the neck of the metal connecting the tab 82 and the connection 83 will be displaced below the surrounding metal of the tab 80

and the box end to form a passage 84 which acts as one

air ventilation during the pouring or drinking operation.

This improves the pouring and drinking characteristics of the tip, especially the drinking characteristics in the case a : the user's mouth substantially covers the pouring opening.

A modification of the embodiment in fig. 17 - 19 are shown

in fig. 2. In this embodiment, the pour and pressure release tabs 80' and 82' are identical in construction to tabs 80

and 82, but the position of the tab 82 is reversed so that the main working part of this is outside the pouring tab 80' and the tab 82" is connected to the tab 80' at 83'.

The main advantages of this embodiment in relation to the previous embodiment are that the pouring flap 80' cannot be accidentally opened when the pressure release flap 82' is opened and a larger air ventilation passage is formed when the large flap is opened because the main working part of the flap 82' is removed from its opening when the flap 80' is opened to the position shown in fig. 19.

In the same pouring/drinking characteristics can be achieved without

using a resealable pressure release tab of the type shown in fig. 13. However, the use of this type of tab is preferred for the reasons expressed in our previous application.

In fig. 21, the box end is formed with a fully cut closure member or tab 90 that overlaps with and underlies the metal surrounding the opening in the same manner as for tab 80. The tabs 90 are hinged to the end about 91 and a small non-resealable pressure release closure tab 92 is formed above the hinge line with part of the tab 92 projecting into the tab 90. The tab 92 is formed in substantially the same manner as the tab 82, except that it is hinged at the end about 93 in such a way that the metal defining the connection is permanently deformed when the tab 92 is opened to release pressure in the jug. When the pouring tab 90 is opened, the tab 92 is further opened as in the previous embodiment to create a permanent ventilation passage for the pouring/drinking operations.

The embodiment in fig. 21 can also be modified accordingly

manner as the embodiment in fig. 19 by turning tab 92.

It will be understood that in each of the foregoing embodiments

the shape of each of the tabs can be varied according to the designer's choice. E.g. as shown in fig. 22, the embodiment in fig. 17 so that tab 80" is oblate and tab 82" is formed with a circular working portion having a straight-sided neck extending from said portion to connection 83". In a similar manner, tab 80 or tab 82"

be pear-shaped as shown in fig. 9. Tabs 90 and 92 in fig. 20 can be modified in a corresponding way.

A further modification is shown in fig. 23. In this embodiment, tab 100 is pear-shaped, and its hinge 101

is placed adjacent to the recess of the box end. The pressure release tab 102 is similar to the tab 82 and has its connection 103 to the end located outside the tab 100 and separate from the hinge 101. The two tabs have the same basic construction as in the previous embodiments.

The above-mentioned embodiment opens in a similar way to the closing device shown in fig. 17 - 19, but the tab 102 does not act as a ventilation during pouring and drinking.

Instead, the opening formed by the tab 102 and the tab 100 opens allows further emptying of the contents of the box and thereby overcomes one of the problems naturally associated with the location of the hinge 101 near the recess.

It may be desirable where the hinges of the tabs 80, 90 and 80" and the tabs 82, 92 and 82" are located near the center of the box end, and limit the extent to which the tabs can be bent about their hinges. This can be achieved by forming a notch or otherwise suitably shaping the underside of the tabs 80, 90 and 80" so that the front edges of the tabs 82, 92 and 82" engage within the notch or shaping whereby the tabs 82, 92 and 82" acts as a strut to prevent further bending movement of the respective tabs 80, 90 and 80".

In certain cases, this function can be achieved to a sufficient extent by frictional contact between the two tabs or by the sealant applied to the tabs. Such a device reduces the likelihood that the hinge metals connecting the tabs to their ends will be subject to breakage. This is not a problem with the embodiment in fig. 23, as the box wall prevents bending beyond approx. 90°.

The embodiments in fig. 17, 20 and 21 have a certain similarity to the box end described in US patent 3 741 4 32 in that the pressure release tabs are placed partly within the pouring tabs. In the present invention, however, the pressure release tab is partially located outside the pouring tab and its hinge or connection does not coincide with the hinge connection of the pouring tab to the end. This provides the distinct advantage that a separate air ventilation passage, outside the boundaries of the opening closed by the pouring flap, is formed when the pouring flap is opened, whether or not the pressure-release flap has been previously opened. Although the aforementioned US patent describes that the release-vent flap 21 remains open when the flap 15 is opened to create an air outlet opening, it is unlikely that this opening contributes much to the ventilation of the contents during normal pouring or drinking from the can as sufficient air will get access through the box opening. If, however, the box is poured so that the main opening is submerged in liquid, the opening formed by the tab 21 will also be submerged and thereby prevent access of air to the box.

In the embodiments described above, the separate air vent passage will remain open even when the pour opening is full of liquid as the vent tab extends outside the pour opening. Furthermore, the air ventilation passages formed in the present embodiments are less likely to be covered during the drinking operation, even if the entire pouring opening is covered by the user's mouth.

The designs of the openings shown in the various

fig. 3, 6, 7 and 14 are not essential and can be modified without affecting the performance of the closure as described above. It will be understood that the sides of the pear-shaped opening 21 can be slightly curved outwards to give the opening a more attractive exterior. In a similar way, the pressure release tab 29 can be used

instead of the tab 11 as shown in fig. 2 or can be formed in a closure device of any other suitable design.

Although each of the above-mentioned embodiments includes fully scored tabs, the invention is equally applicable to closure devices defined by score lines or other purposes by lines of weakness, as discussed in US Patent 3,334,775.

The closing devices in the present invention can be used

in box ends or in other container elements, and may be formed from any suitable sheet metal material, including aluminum and steel, and may be of any suitable shape, depending on the shape of the box body to which the box end or other container element is to be attached.

It will also be understood that the closure devices can be made of plastic materials using appropriate plunge techniques.

There is no critical limit as regards the absolute size of the pouring-closing device, although normally the pouring-closing device will be of such a size that the complete insertion of a user's finger is prevented, yet large enough to allow sufficient outflow of the liquid container contents. Likewise, the absolute size of the pressure release/vent hole or opening is not critical, but normally the opening will be of a size that prevents complete insertion of a user's finger, yet is large enough to allow sufficient outflow of internal container pressure by pressure release, and to allow sufficient inflow of air by ventilation.

The sealing agent used for fully split closures may be of any agent or material,

such as a sealant, plastic tape, adhesive foil, heat-fusible material, a combination of these, etc. A particularly suitable sealant is a plastisol-type polyvinyl chloride combined with a common plasticizer and composition ingredients. Such a plastisol will be thermoset to form a non-tacky, somewhat pliable solid material which helps to hold the closure in place and maintain

a hermetic seal under the pressure of sizes that normally appear in cans of carbonated drinks and malt. The sealing agent must be sufficiently fragile to be able to be torn open by the application of finger-induced impression force on the respective closing devices. The maximum angular displacements of the closing device as mentioned above only apply to the specified type of aluminum and the specified thickness of this. Changes to these and other variables in the closure design will change the maximum allowable displacement angle.

Claims (24)

1. Push-in pressure release closure device (10, 28 28', 55, 55', 72, 82, 82', 82'', 92, 102) in a container element suitable for liquids under pressure, comprising a closure element (11, 28 , 28', 36, 55 55', 72, 82, 82', 82'', 92, 102) formed in one piece from a portion of the container element and defined by at least one line of weakness and sized to be opened by a finger force against the action of the pressure, the closing element (11, 28, 28', 36, 55, 55', 72. 27, 27', 35, 57, 76, 83, 83', 83'', 93, 103) to the container element, characterized in that the closing element (11, 28, 28', 36, 55, 55', 72, 82, 82', 82'', 92, 102) and the part of the container element which surrounds the closing element (11, 28, 28', 36, 55, 55', 72, 82, 82', 82'', 92, 102) comprise means to substantially prevent permanent opening of the closing element (11, 28, 28', 36, 55, 55', 72, 82, 82', 82'', 92, 102) by an unlimited finger-induced impression force, whereby the closing element (11, 28, 28', 36, 55 . from the inside of the container. 2. Closing device as set forth in claim 1, characterized in that the closing element (11) is designed to prevent deflection of the closing element (11) by a finger-induced indentation force outside the angle at which the elastic limit for the metal in the connection (13) is exceeded. 3. Closing device as stated in claim 1, characterized in that the working part (12) is raised relative to the surrounding part of the container element, where the degree by which the working part (12) is raised and/or the effective size of the working part - (12) is available for a finger-induced indentation force, is chosen so that under normal conditions of use the finger-induced force is not able to bend the closing element (11) about the connection (13) past the angle the elastic limit of the metal forming the connection (12) is exceeded, whereby application of the opening force does not permanently open the closing mechanism (10) at least while the closing element (11) is exposed to the pressure in the container element. 4. Closing device as specified in claim 2 or 3, characterized in that the working part (12) and the connection (13) are sufficiently apart to prevent deflection past the mentioned angle. 5. Closing device as stated in claim 3, characterized in that the container element is formed with a pour-close element (20) defined by at least one line of weakness, where the pour-close element (20) has a narrow end and a wide end, where the pressure-triggering the closing element (20) and placed at the narrow end thereof, the connection being defined by a narrow neck (27) of metal between two lines (25, 26) which is at least weakened so that they are divided by the impression force, and which extends towards each other from opposite edges of the pour-close element (20). 6. Closing device as set forth in claim 5, characterized in that the pour-close element (20) is completely separated from the container element except for a metal neck (22) which acts as a hinge for the pour-close element (20) during the opening operation thereof, the two lines (25, 26) are dividing lines formed in the pouring-closing element (20). 7. Closing device as stated in claim 6, characterized in that the pouring-closing element (20) is in an overlapping underlying relationship with the surrounding parts of the container element, the metal on each side of the dividing lines (25, 26) being mostly in the same plane. 8. Closing device as stated in claim 7, characterized in that the container element is a box end, where the narrow end of the pour-close element (20) is formed adjacent to the middle of the end. 9. Closing device as stated in claim 3, characterized in that the container element is formed with a pouring closing element (20') defined by at least one weakening line, where the closing element (20') has an uneven shape with a narrow end and a wide end , where said pressure-triggered closing element (20') is formed as part of the pouring closing element and is located at the narrow end thereof, the connection being defined by narrow necks (27; 27') of metal extending inwards from opposite edges of the pouring - the closing element (20) to a line (25') which is at least weakened so as to be divided by the impact force, the line (25') extending largely across the pouring closing element (20'). 10. Closing device as stated in claim 9, characterized in that the line (25') is a dividing line formed in the closing element (20'). 11. Closing device as set forth in claim 4, characterized in that it further comprises a pour-close element (31) formed in the container element, the pressure-releasing closure element (34) being formed as a uniform extension of the pour-close element (31), as the pressure-release -the releasing closure element (34) is removed from its closed position when the pouring closure element (31) is opened, whereby an air ventilation opening is provided for the pouring operation. 12. Closing device as stated in claim 11, characterized in that the pour-close element (31) is completely cut from the container element except for a neck (32) made of metal which acts as a hinge for the pour-close element (31) during its opening operation. 13. Closing device as stated in claim 4, characterized in that the pressure-triggering closing element (55; 55') is completely cut from the receiver element, the working part (56) being arranged at one end of a narrow elongated part that leads to the connection ( 57), and as the working part (56) is in an overlapping underlying relationship with the surrounding parts of the container element. 14. Closing device as stated in claim 13, characterized in that the pressure-triggering closing element (55; 55') is formed at least substantially within a larger closing device (50) which can act as a pouring closing element. 15. Box end for a container, preferably for liquids under pressure, including a liquid pouring closure device (P) and a pressure-triggered closure device (11) in said end which can be opened by a finger-induced indentation force, characterized in that the pressure-triggered closure device (11) cooperates with portions of the box end surrounding the pressure release closure device (11) to physically limit the depression of the pressure release closure device (11) caused by the finger applied indentation force to cause the pressure release closure device (11) to return substantially to its closed position in the absence of the finger-induced impression power. 16. Box end as specified in claim 15, characterized in that the pressure-releasing closing element (11) is designed to prevent its deflection by the finger-induced impression force past the angle at which the yield point of the metal in the connection (13) is exceeded. 17. Container element including the closing device as specified in any one of claims 1-4, with a pour-close element (80) defined by at least one line of weakness in the container element, characterized in that the pressure-triggering closure device (82) is formed partially within the pour-close device (80) and partially outside the pour closure device (80), the pressure release closure device (82) being arranged to open permanently upon opening of the pour closure device (80) to create an air vent passage (84) to assist valves - none of the contents of the container when pouring or drinking from it. 18. Container element for use in a container for liquid under pressure, where the container element includes an impressionable closure device (80, 80', 80'', 90; 100) which is easy to open and defined by at least one line of weakness, and a less pressure-triggering closure device (82, 82', 82'', 92; 102) defined by at least one line of weakness and able to be opened by means of an impression force, characterized in that the pressure-triggered closing device (82, 82', 82'', 92; 102) is formed partly inside the pouring closing device (80, 80', 80'', 90; 100) and partly outside the pouring closing device (80, 80', 80'', 90; 100), as the pressure-triggering closing device (82, 82', 82'', 92; 102) is arranged to be permanently open upon opening of the pour-close device (80, 80', 80'', 90; 100) to create an air vent passage (84) to assist with valves - none of the contents of the container while pouring or drinking from it. 19. Container element as stated in claim 17 or 18, characterized in that the container element is formed from sheet metal, where the pour-close device (80, 80', 80'', 90) and the pressure release closure seal (82, 82', 82'', 92) are completely cut from the sheet metal except for a portion (81, 91; 83, 83', 83'', 93) which connects the closure devices (80, 80', 80'', 90, 82, 82', 82'', 92) with the container element, the pouring closure device (80, 80', 80'', 90) and the pressure release closure device (82, 82', 82'', 92) overlap and underlie sheet metal surrounding the opening closed by the closure devices (80, 80', 80'', 90, 82, 82 ' , 82' ' , 92) . 20. Container element as stated in claim 18, characterized in that the pressure-releasing closure device (82, 82', 82'') is connected in one with the container element or with the pouring closure device (80, 80', 80'', 90 ), that the pressure-triggered closing device (82, 82', 82'') bends around the connection (83, 83', 83'') during the opening operation, and that the pressure-triggered closing device (82, 82', 82'') is constructed to return essentially to its closed position in the absence of the impression force. 21. Container element as stated in claim 20, characterized in that the pressure-releasing closing device (82, 82', 82'') is designed to prevent its deflection by a finger-induced indentation force past the angle at which the elastic limit of the metal in the connection (83, 83 ', 83'') are exceeded. 22. Container element as set forth in claim 21, characterized in that the pressure-triggering closure device (82, 82', 82'') is located sufficiently from its connection with the container element to prevent deflection of the connection (83, 83', 83'') past the angle . 23. Container element as stated in claim 18, characterized in that the pressure-triggered closing seal (92) is connected in one with the container element and about which connection (93) the pressure-triggered closing device (92) is hinged during the opening operation, the pressure-triggered closing device (92) being designed to permanently deform the connection (93) when opening it. 24. Container element as set forth in claim 17 or 18, characterized in that the pouring closure device (100) and the pressure-triggering closure device (102) are fixed together with the container end at a place adjacent to the periphery of the end, whereby the permanently opened pressure-triggering closure device (102 ) creates a liquid drainage opening that enables substantially complete drainage of the contents of a liquid-filled container having a container end.