HK1172597B - Lid for containers of substances and container of substances thus equipped - Google Patents

Abstract

A lid (20) for a container (21),The lid (20) comprises a substantially circular central surface (27),There is a weakened line (30) on the surface,Used to define a closing element (39) located on the central surface (27) that can be opened by tension;A driving wing (22),The driving wing has at least a first end (25) as a fulcrum,The first end (25) is located outside the weakened line (30),The driving wing (22) is connected to the closing element (39) through rivets (23) and can be driven to move the closing element (39) upward,Make it detach along the weakened line (30).The weakening line (30) is disconnected at the end of the closing element (39) opposite to the driving wing (22), so that the closing element (39) has a connecting piece (34) firmly connected to other parts of the central surface (27).When the lid is made of aluminum, the distance between the rivet and the front end of the closing element (39) is 1.5 to 3.5mm.When the lid is made of ferroalloy, the distance is 4.0 to 6.0mm.

Description

Cap for container for substance and container provided with same

Technical Field

The present invention relates to a lid and a container provided with such a lid, which container is normally used for storing liquids, but can also be used for storing granular or other forms of solid matter.

The invention relates in particular to a lid, and a container provided with such a lid, wherein a closing member closes a supply opening which is part of the lid, the closing member being integral with the lid in an initial state, the closing member not entering the inside of the container at any time during the pulling and opening steps, when the closing member is at least partially pulled away from the rest of the lid.

According to the invention, the lid may be made of aluminium, or a similar or equivalent aluminium alloy, or a similar or equivalent iron alloy.

Background

Lids and containers provided with such lids are known and are commonly used for storing beverages and, in some cases, other substances.

The containers are generally substantially cylindrical, but they may also have a substantially quadrangular section, extending along an axis perpendicular to said section.

With regard to the lids of these known containers, a supply hole can be formed by pulling off a very small portion of the lid, by means of a breaking line provided beforehand in the lid.

US-A-3.731.836 describes an opening system of A closing plug defined by A line of weakening of the closure of the can; in this solution, a tab of the lever or flap (which is located substantially in a central position) is used to open the closure plug. The lever has a pivot point corresponding to the edge of the upper wall of the can, and a rivet-type fixing means is provided between the tab and the pivot point.

Between the tab and the lid of the can, there is provided an elastic connecting element, the lever or tab acting on the portion of the can lid outside the closing plug, so that in the first opening movement the plug is lifted and pulled upwards, rotating along the pin, which opening process and the use of the container present problems in terms of time and safety.

WO-A-01/02260 describes an opening system for A closure plug defined by A closed line of weakness of A can; the lever or tab of the can has an associated tab, the fulcrum of which is located at the edge of the can lid; the pull ring is positioned in the center; a rivet located between the fulcrum and the tab attaches the opening lever or tab to the stopper.

In this solution, the movement of the lever or tab provides a pushing action of the stopper in the inward direction, creating a first break of the line of weakening, since the fulcrum of the lever or tab matches the line of weakening defining the stopper of the can. The lever or tab then acts as a pulling element to remove the plug.

This system allows the contents to come into contact with the outer surface of the tab.

Moreover, this system is dangerous to use.

US-A-5.145.086 describes an opening system of A closing plug defined by A closed line of weakness of the can; the tab of the opening lever or tab is in a central position; the lever or tab has a fulcrum corresponding to the periphery of the can lid and a rivet is used to attach the opening lever or tab to the can stopper.

The lever or tab acts on the portion of the can lid outside the closure so that in the first opening movement the stopper is lifted and pulled upwards and cannot be pushed inside the can.

This solution presents safety problems for the user during opening and during use of the container.

US-A-3.795.340 describes A system for opening cans with A lever or tab having A peripheral fulcrum and A central tab.

Such a can stopper occupies most of the space of the upper wall of the can, the can stopper being defined by a closed annular line of weakness substantially overlapping the periphery of the can.

The lever or tab acts on the inside of the closed annular weakening line, so that, in the first opening movement, the stopper is pushed inside and then completely removed by the pulling action.

This system also allows the contents to come into contact with the outer surface of the tab.

In addition, in this solution, the system is also dangerous in use.

US-A-4.189.060 describes A system for opening A can with A lever or tab for pulling off A stopper in A conventional manner.

The pull ring of the lever is usually located in a central position and the fulcrum of the lever is located at the periphery.

As in the prior art described above, the rotation of the lever does not cause the breaking of a portion of the closing plug, but merely places the lever in the operating position in which it is actuated to cause the closing plug to be pulled up in correspondence with the projection of the hole.

The lever is connected to the can lid by a connecting element comprising an elastic member, also in the open position.

This system is not only complex, but also laborious. In addition, this system is dangerous in use.

US-A-3.386.613 has A forked lever with A rivet rotatably connected to the front section of the lever. In this form a concentrated point of application is not available to pull the stopper apart. Moreover, what this scheme provided is a mechanical type's articulated, can't cover the length of pole for can't provide any auxiliary force for the anterior segment fulcrum when the fracture begins, this makes the fracture start comparatively difficult.

US-A-2007/131.693 provides A lid with A line of disruption extending along the periphery of the lid; further, the tab is broken from its leading end portion. And a portion of the opening member may enter the interior of the container.

The tab provided in WO-A-03/010054 is open starting from the inside of the lid and extends until the entire stopper is completely removed from the lid.

WO-A-00/58161 provides A stay on tab in which the plug penetrates into the interior of the container.

The solution of the present invention is preferably, but not exclusively, applicable to beverage container lids with the object of overcoming the limitations of the prior art and providing a system with new and unexpected advantages.

It is A further object of the present invention to improve and perfect the invention of WO-A-2009/030526.

Disclosure of Invention

The invention is characterized by what is set forth in the independent claims, while the dependent claims are based on different variants of the invention.

The object of the present invention is to obtain a system in which a closing element or plug of limited size with respect to the lid can be easily and effortlessly detached from the lid portion. Furthermore, the invention also aims to prevent the plug from entering the container (even temporarily), since the plug is immediately lifted with respect to the surface of the lid.

As an alternative to the invention, once the aperture is opened, the closing plug and associated drive wing remain within the rim body (perimeter bulk) of the container to prevent risk while holding the container.

The edge of the stopper is defined by a line of disruption (or weakening) of the type known in the art.

The driving wing or rod is also of a known type, having an appendage with an elastic portion, fixed to the driving wing; the attachment flap is fixed to an element functioning as a plug by means of rivets or the like.

According to the invention, the gripping part of the drive wing is directed towards the centre of the lid, while the front end portion (or first end) acting as a fulcrum is directly engaged with the edge of the substantially flat central surface of the lid. According to the invention, the central surface may also be slightly rounded.

In this solution, the fulcrum cooperates with a groove in the periphery of the central surface, which acts as a member opposing the force applied to the fulcrum, preventing an increase in the force or other negative effects due to the bending of the central portion of the lid.

As an alternative, a ridge for stiffening, solidification and hardening is provided by increasing the surface on which the front end portion (fulcrum portion) of the drive wing acts. The effect of the flap can be further improved by obtaining said stiffening effect by further hardening the point at which the fulcrum acts. Also, by constructing a region (even if tiny) that allows the fulcrum to operate, the requirement for accuracy can be reduced.

As an alternative, the ridges may be obtained by casting.

By operating the tab upwards, a lever action is created on the gripping member towards the inside of the lid, transforming said operation into an action of lifting the element constituting the stopper upwards, so that said element does not enter the inside of the container.

According to the invention, the lifting operation is substantially initiated on the shaft of the driving wing, adjacent to the connecting rivet between the elastic portion and the plug element. Preferably, the fracture initiation location is 1.5-3.5mm, preferably about 2.0-2.5mm, from the axis of the rivet, in order to maximize leverage and minimize the required pulling force.

According to another variant of the invention, in the area where the pulling force starts, there is also provided a zone of reduced thickness in which the thickness of the material constituting the lid is reduced (for example by means of compression), whereby the force required to initiate the fracture-lifting can be further reduced.

According to another version of the invention, the plug has a configuration extending towards the fulcrum, in the region close to the start of the fracture-lifting, so as to form a concentrated segment to assist in initiating the lifting/fracture, further reducing the force required.

According to another variant of the invention, the plug extends towards the centre of the lid, possibly also beyond the centre of the lid, by means of a web (connected to the plug) set by means of a known engraving method. The connecting piece is used for connecting the combined stopper-driving wing to the cover.

According to the solution of the invention, the stopper may be substantially circular, oval, drop-shaped, etc., as this is not relevant for the purpose of the invention.

According to an aspect of the invention, the plug is located inside the region of the peripheral region of increased deformation defined by the reinforcing rim. Thus, by placing the said areas together with the attached peripheral reinforcing deformations, the deformed surface can be reinforced, thus being flat and hardened. The region of the reinforcing rim may also be formed by casting to further promote stiffening and leveling to strengthen the material.

The central surface of the lid is connected to the stopper by a web, i.e. through the neck of the stopper. The two side edges of the connecting piece may be parallel, or in the shape of an inverted "W", or in the shape of an upside down and inverted "C".

According to another version of the invention, adjacent to the neck there is a reinforced zone obtained by deforming the flat surface, so as to maintain a thin connection between the tab and the stopper, while preventing breakage during opening or during use.

According to another variant of the invention, the rear portion of the tabs has respective elastic connectors which diverge in opposite directions to facilitate the reuse of the plug.

According to another aspect of the invention, the resilient connecting element may be engaged with or within the region of increased deformation.

According to another aspect of the invention, the elastic connection member may be located outside the region of increased deformation.

According to another aspect of the invention, the resilient connecting element may be adjacent to the stiffening rim.

The relative position between the elastic connector and the reinforcing rim makes it possible to always select the desired degree of opening and the amount of elasticity.

According to another aspect of the invention, the plug is further provided with a region of increased deformation, thereby rendering the plug non-deformable.

According to another aspect of the invention, when the diameter (Φ) of the central surface of the substantially flat or slightly rounded lid is set to 47 (mm), the invention provides the following relative values (in mm) (as shown in fig. 4 and 4 a):

the distance (a) of the forwardmost portion of the centralised section from the edge of the lid is 4-7, preferably 5-6, to take advantage of the rigidity provided by the peripheral groove to reduce or eliminate bending;

the distance (b) between the centre and the edge of the rivet is 6-9, preferably 6.5-8.5 when the material is aluminium or an aluminium alloy or the like and 9.0-11.0 when the material is iron or an iron alloy or the like, so that the rivet is as close as possible to the centralised section to reduce the required tension; therefore, the difference (b-a) is 1.5 to 3.5, preferably 2.0 to 2.5 when the material is aluminum or an aluminum alloy, and 4.0 to 6.0, preferably 4.5 to 5.0 when the material is an iron alloy or the like.

The diameter of the rivet body (rivet) is preferably 2.5 to 3.5 when the material is aluminum or an aluminum alloy, and 6.0 to 10.0 when the material is an iron alloy or the like;

the distance (c) between the neck and the edge is 20-33, preferably 24-28, to form a liquid outlet interval of a size suitable for controlling the liquid outlet;

the part furthest from the rim or peripheral groove is at a distance (d) from the rim of 25-40, preferably 20-60, of the resilient connection to keep all components inside the container body in the open state of the stopper;

the width (e) of the connecting piece is at least 4-10, preferably 6-8, to obtain better control of the elasticity;

the width (f) of the plug is maximally 15-30, preferably 18-25;

the width (g) of the strengthening deformation zone is at most 20-40, preferably 25-31, to obtain accurate control of deformation and connection advantages.

Drawings

The various features to which the invention relates will be more apparent from the following description of a preferred embodiment, which is not to be taken as a limiting example, and from the following figures of the drawing.

Fig. 1 is a schematic view of a container of the present invention with the lid in a semi-closed position.

Fig. 2 is a schematic view of the container of fig. 1, with the lid further opened.

Fig. 3 is a schematic view of the container of fig. 1 with the lid in an open state.

Fig. 4 is a plan view of the cap of the present invention.

Fig. 4a is a schematic cross-sectional view of the cap of fig. 4.

Figure 5 is a first variation of the cap shown in figure 4.

Fig. 6 is a second variation of the cap shown in fig. 4.

Fig. 7 is a third variation of the lid of fig. 4.

Fig. 8 is a fourth variation of the lid of fig. 4.

Fig. 9 is a fifth alternative to the cap of fig. 4.

Fig. 10 is a sixth variation of the cap of fig. 4.

Fig. 11 is a seventh variation of the lid of fig. 4.

Fig. 12 is an eighth variation of the lid of fig. 4.

Fig. 13 is a ninth variation of the lid of fig. 4.

Fig. 14 is a tenth variation of the lid of fig. 4.

Detailed description of the preferred embodiments

With reference to figures 1, 2, 3 and 4, the container 21 for the substance (in this case the beverage) is shown in its entirety, for example made of aluminium, steel or another alloy, substantially in the form of a cylinder, having an outer side 40, a lid 20 and a bottom, which can be of any type and is not shown in the figures.

The lid 20 is substantially circular, coaxial with the central axis Y of the container 21 (fig. 4 a), and has an annular outer periphery 41, the outer periphery 41 surrounding the central surface 27 having a radius "Φ" and defining an outer peripheral groove 52.

In the alternative, the central surface may be completely or at least partially flat, or rounded.

On the central surface 27, a weakening line 30 (fig. 4-14) or cut is provided, by known methods, having an open configuration with a locally reduced or variable section, defining a closing element or plug 39 of circular, oval or drop-shape.

In the example shown here, the plug 39 has a reinforcing zone 38 in the centre, this reinforcing zone 38 being substantially quadrangular and being able to set a plug 39 with greater rigidity so as to facilitate and guide the step of breaking the plug 39 off the central surface 27 along the weakening line 30 in a desired manner.

In this example, the front portion of the line of weakness 30 has a concentrated section 29, the concentrated section 29 being tapered relative to the shape of the stopper 30 defined by the line of weakness 30.

The centring portion 29 is the starting point of the fracture and from which the fracture develops, as will be described in detail below, the centring portion 29 can centralise the opening action exerted by the user, so as to assist in pulling apart the stopper 39 and thus opening the respective supply hole 45.

In fact, since the plug 39 is normally associated with the lid 20, the plug 39 closes the supply hole 45 for the beverage to be conducted out of the container 10.

In particular, when the container 21 is in the closed condition, the plug 39 completely closes the aperture 45, whereas when the container 21 is opened (fig. 3), the plug 39 has been at least partially lifted, although the plug 39 is still substantially located in the central surface 27, remaining in fixed connection with the remainder of the container 21.

As will be described in detail below, the plug 39 is fixedly attached to the drive wing 22, at least partially overlapping in the closed condition.

The drive wing 22 can be manually actuated by means of the grasping tip or ring 26 to separate the stopper 39 from the remainder of the cap 20 along the line of weakness 30 or pre-cut line.

At a lateral position on the drive wing 22 corresponding to the ring 26, a bead 37 may be provided, which also makes it possible to secure the drive wing 22 with the lid 20 to facilitate its removal. The drive wing 22 has a fulcrum at the front end portion 25 (fig. 4), the front end portion 25 substantially mating with the peripheral groove 52.

The peripheral groove 52 has at least one vertical or almost vertical edge, thereby providing a strong resistance to deformation, even elastic deformation.

The driving wing 22 has an intermediate zone 46 between the grip ring 26 and the front portion 25, the elastic member 24 being confined to this intermediate zone 46, the elastic member 24 being in contact with the plug 39; the elastic member 24 is restrained toward the front end portion 25.

The intermediate zone 46 is connected to the plug 39 by means of a rivet 23 adjacent to the concentration section 29.

By acting on the pull ring 26, the drive wing 22 starts a rotational movement around the front end portion 25. This moves the intermediate region 46 away from the central surface 27 (fig. 1) and the plug 39 is relatively partially detached from the central surface 27 starting from the centering section 29, so that the hole 45 starts to open.

Due to the close proximity between the front portion 25, the connection area of the intermediate region 46 to the elastic member 24 and the connection area of the elastic member 24 to the plug 39, the driving wing 22 provides a very advantageous driving means, achieving a high angular moment with a limited driving force.

Further, the driving force of the driving wing 22 is applied to a point adjacent to the concentrated section 29 of the weakening line 13 and rotates toward the outside of the container 10.

In addition, a reduced thickness region 28 is provided in correspondence with the concentrator section 29 to further assist in pulling the stopper 39 away from the central surface 27 along the line of weakness 30.

Thus, from the foregoing, it is apparent that the force required to lift stopper 39 along line of weakness 30 is significantly lower than sanitary stoppers or outwardly opening stoppers known in the art.

Further upward movement of the drive wing (fig. 2) allows the bung 39 to be fully removed from the central surface 27 and placed in a collapsed condition (fig. 3).

The rear portion of the plug 39 has a substantially rectangular connecting tab 34, connected to the plug 39 itself, defined by the rear portion of the line of weakness 30.

The tabs 34 firmly connect the plug 39 to the rest of the central surface 27, preventing the former from separating from the latter, even in the open condition.

At the rear, the connecting piece 34 ends with two elastic connections 36 defined by the terminal ends of the weakening line 30.

The resilient connecting elements 36 diverge in opposite directions relative to the central axis of the web 34.

The tab 34 also has a central reinforcing zone 35 which extends substantially from the neck 33 to the elastic connection 36 to reinforce the tab 34 against breakage during opening of the lid 20.

The lid 20 also has a region of reinforced deformation 31, the periphery of which is defined by a reinforcing rim 32 provided on the central surface 27.

Preferably, the reinforcing rim 32 annularly surrounds the plug 39, so that the weakening line 30 is completely located inside the region of intensified deformation 31.

The resilient connector 36 may be located inside, outside or in cooperation with the reinforcing rim 32, depending on the elastic requirements.

Preferably, the reinforcing rim 32 may be given a particular shape so that the corresponding reinforcing deformation zone 31 is located below (or above) the plane of the central surface 27, so as to withstand with greater efficiency the upward pulling force exerted when removing the plug 39.

In this way, possible deformations of the central surface 27 upon opening the plug 39 are reduced to a minimum.

In the embodiment shown in fig. 5, the shape of the cover 20 substantially corresponds to the embodiment shown in fig. 1-4, except for the ring 26 of the drive wings 22.

In fact, in this embodiment, the rear portion of the ring 26 is also provided with a gripping bridge 47 which is arched upwards with respect to the remaining portion of the drive wings 22 to facilitate the user's insertion of his fingertips and/or nails between the drive wings 22 and the central surface 27, to start lifting the drive wings 22 and to lift the plug 39.

In the embodiment shown in fig. 6, the shape of the lid 20 of this embodiment substantially corresponds to the embodiment shown in fig. 1-4, except for the resilient member 24. In this arrangement, the resilient member 24 is confined within the intermediate region 46 in a direction toward the grip ring 26.

In this solution, the mechanical and dynamic conditions for lifting the plug 39 are partially changed after lifting the drive wing 22. The rupture conditions of the concentrated section 29 and the weakening line 30 are therefore also different from the solutions shown in figures 1-4, 5.

In the embodiment shown in fig. 7, the shape of the cover 20 of this embodiment substantially corresponds to the embodiment shown in fig. 1-4, except that the distance "b" between the center of the rivet 23 and the front end portion 25 of the drive wing 22 is at its greatest extension, so that it is away from the hub section 29.

Unlike the solution shown in figures 1-4 and 5, in this solution the mechanical and dynamic conditions for lifting the stopper 39 are also partially changed after the lifting of the driving wing 22, and therefore the conditions of rupture of the concentration section 29 and of the weakening line 30 are also different.

In the embodiment shown in fig. 8, the cover 20 of this embodiment has a shape substantially corresponding to the embodiment shown in fig. 1-4, except that the connecting piece 34 has a longer shape, thereby increasing the distance "d" between the resilient connecting member 36 and the front end portion 25 of the driving wing 22. The resilient connecting element 36 also serves to prevent further development of the fracture during opening.

In the embodiment shown in fig. 9, the cover 20 of this embodiment is shaped substantially in accordance with the embodiment shown in fig. 1-4, except that an upwardly facing ridge 49 is also provided near the outer periphery 41, in an area corresponding to the central surface 27 to which the front end portion 25 of the drive wing 22 is pivoted.

In this solution, the front portion 25 is in direct contact with the ridge 49 to release the pressure onto the latter during opening. In this solution, possible deformations of the central surface 27 are further prevented due to the pressure relief during opening.

In the embodiment shown in fig. 10, the lid 20 of this embodiment is substantially identical in shape to the embodiment shown in fig. 1-4, except that the line of weakness 30 defining the shape of the plug 39 has two lateral projections 50.

The lateral projections 50 give the plug 39 a laterally elongated shape, so as to be easier to remove from the central surface 27.

In the embodiment shown in fig. 11, the cover 20 of this embodiment is shaped substantially in accordance with the embodiment shown in fig. 1-4, except that the connecting piece 34 has a construction which is as short as possible, so that the distance "d" between the elastic connecting piece 36 and the front end portion 25 of the driving wing 22 is shortened.

In the embodiment shown in fig. 12, the cover 20 of this embodiment has a shape substantially corresponding to the embodiment shown in fig. 1-4, except that the connecting piece 34 does not have a central reinforcing area 35 and instead has a gripping seat 51, the end portion of the gripping ring 26 at least partially overlapping the gripping seat 51.

The function of the gripping shoe 51 is to assist the user's fingertips and/or nails in reaching between the drive wings 22 and the central surface 27 to begin lifting the drive wings 22 and to lift the stopper 39.

In the embodiment shown in fig. 13, the shape of the lid 20 of this embodiment substantially corresponds to the embodiment shown in fig. 1-4, except that the reinforcing rim 32 of the reinforcing deformation zone 31 is closed and the reinforcing rim 32 extends beyond the resilient connecting element 36, thereby containing the resilient connecting element 36 within the reinforcing deformation zone 31.

In this way, the possibility of deformation of the central surface 27 during opening of the plug 39 is further reduced.

In the embodiment shown in fig. 14, the shape of the lid 20 of this embodiment substantially corresponds to the embodiment shown in fig. 13, except that the reinforcing rim 32 of the reinforcing deformation zone 31 is open, and the reinforcing rim 32 extends beyond the elastic connecting member 36, thereby containing the elastic connecting member 36 within the reinforcing deformation zone 31.

It is understood, however, that certain modifications and/or additions may be made to the parts of the lid 20 of the container 21 as described heretofore, without departing from the field and scope of the present invention.

Furthermore, although the present invention has been described with reference to specific examples, it is obvious to a person skilled in the art that other equivalent forms of container lids or containers equipped with such lids may be obtained therefrom, provided that they have the characteristics as set forth in the following claims, which fall within the scope of protection of the present invention.

Claims (16)

1. A lid for a container that can hold a liquid or powder, the lid comprising:

-at least one substantially circular central surface (27) coaxial with a central axis (Y) of the container (21), on the central surface (27) there being a line of weakening (30), said line of weakening (30) defining a plug-type closing element (39) of an opening (45) in the central surface (27), the plug-type closing element (39) being openable by a pulling force;

and a driving wing (22), the driving wing (22) having at least one first end (25) located outside the weakening line (30) as a fulcrum, and a middle elastic zone (24) fixed to the driving wing (22), the driving wing (22) being connected to the plug-type closing element (39) by means of a rivet (23) and being drivable to move the plug-type closing element (39) upwards to disengage it along the weakening line (30);

-said weakening line (30) is broken at the end of the plug-type closing element (39) opposite to said drive wing (22) with respect to the central axis (Y), whereby said plug-type closing element (39) has a connecting piece (34) made in relief firmly connected with the rest of said central surface (27);

the method is characterized in that:

the connecting piece (34) is connected to the central surface (27) by means of an elastic connecting piece (36), the elastic connecting piece (36) diverging in opposite directions with respect to the central axis of the connecting piece (34), and

the fulcrum of the driving wing (22) is a central part of the first end (25) and cooperates with the edge of the central surface (27) close to the peripheral groove (52), wherein the front extremity of the plug-type closing element (39) constitutes a concentration section (29).

2. Lid as in claim 1, characterized in that a reinforcing ridge (49) is provided in the area of the fulcrum of the driving wing (22).

3. A cap as claimed in claim 1, characterised in that said plug-type closing element (39) has a reinforcing zone (38).

4. Lid as in claim 1, characterized in that said connecting tab (34) has an at least partially longitudinal stiffening deformation (35).

5. A cap as claimed in claim 1, characterised in that said central surface (27) comprises at least one zone (28) of reduced thickness along the weakening line (30), the zone (28) of reduced thickness corresponding to the zone where the pulling force starts.

6. Lid as in claim 1, characterized in that the front end of said line of weakening (30) has said concentration section (29) corresponding to the area where the pulling force starts, so as to reduce the effort required to pull up the plug-type closing element (39).

7. Lid as in claim 1, characterized in that the connecting tab (34) further comprises a deformation-intensifying area (35), the deformation-intensifying area (35) extending substantially from the connecting neck (33) between the connecting tab (34) and the plug-type closing element (39) to the elastic connecting piece (36) so as to extend over the entire connecting tab (34).

8. A lid as claimed in claim 1, characterised in that said elastic connecting element (36) is located outside the stiffening rim (32).

9. A lid as claimed in claim 1, characterised in that said elastic connecting element (36) is located inside the stiffening rim (32) or cooperates with said stiffening rim (32).

10. Lid as in claim 1, characterized in that said driving wing (22) is arranged to exert a force at a point in abutment against said front extremity of said plug-type closing element (39) constituting a central segment (29).

11. Lid as in claim 1, characterized in that the distance between the axis of the rivet (23) and the front extremity of the plug-type closing element (39) constituting the centring portion (29) is comprised between 1.5 and 3.5mm when the lid is made of aluminium or aluminium alloy, and between 4.0 and 6.0mm when the lid is made of iron alloy.

12. Lid as in claim 1, characterized in that the distance between the axis of the rivet (23) and the front extremity of the plug-type closing element (39) constituting the centring portion (29) is comprised between 2.0 and 2.5mm when the lid is made of aluminium or an aluminium alloy, and between 4.5 and 5.0mm when the lid is made of an iron alloy.

13. Container for containing a liquid or powder, comprising an outer side (40), a lid (20) and a bottom, wherein the lid (20) comprises:

-at least one substantially circular central surface (27) coaxial with a central axis (Y) of the container (21), on the central surface (27) there being a line of weakening (30), said line of weakening (30) defining a plug-type closing element (39) of an opening (45) in the central surface (27), the plug-type closing element (39) being openable by a pulling force;

and a driving wing (22), the driving wing (22) having at least one first end (25) located outside the weakening line (30) as a fulcrum, and a middle elastic zone (24) fixed to the driving wing (22), the driving wing (22) being connected to the plug-type closing element (39) by means of a rivet (23) and being drivable to move the plug-type closing element (39) upwards to disengage it along the weakening line (30);

-said weakening line (30) is broken at the end of the plug-type closing element (39) opposite to said drive wing (22) with respect to the central axis (Y), whereby said plug-type closing element (39) has a connecting piece (34) made in relief firmly connected with the rest of said central surface (27);

the method is characterized in that:

the connecting piece (34) is connected to the central surface (27) by means of an elastic connecting piece (36), the elastic connecting piece (36) diverging in opposite directions with respect to the central axis of the connecting piece (34), and

the fulcrum of the driving wing (22) is a central part of the first end (25) and cooperates with the edge of the central surface (27) close to the peripheral groove (52), wherein the front extremity of the plug-type closing element (39) constitutes a concentration section (29).

14. Container as in claim 13, characterized in that the distance between the axis of the rivet (23) and the front extremity of the plug-type closing element (39) constituting the centring portion (29) is comprised between 1.5 and 3.5mm when the lid is made of aluminium or an aluminium alloy, and between 4.0 and 6.0mm when the lid is made of an iron alloy.

15. Container as in claim 13, characterized in that the distance between the axis of the rivet (23) and the front extremity of the plug-type closing element (39) constituting the centring portion (29) is comprised between 2.0 and 2.5mm when the lid is made of aluminium or an aluminium alloy, and between 4.5 and 5.0mm when the lid is made of an iron alloy.

16. Container according to claim 13, 14 or 15, characterized in that the driving wing (22) is arranged to exert a force at a point in the immediate vicinity of the front end of the plug-type closing element (39) constituting a centring segment (29).