EP0404654A1 - Manufacturing process for a controlled opening closure element for a metal can; closure element obtained by this method; and can utilizing this closure - Google Patents

Abstract

The invention relates to a manufacturing process for a closure element (3), known as a controlled-opening closure element, for a metal can (1), starting from a sheet metal blank, characterised in that the sheet metal blank is pressed to form a rounded zone, a small bent zone is formed from this rounded zone and a cut is made in the region of this bent zone to make an orifice (5) comprising a peripheral skirt (10c), a part of the peripheral skirt (10c) is widened and a removable lid (4) is crimped onto the orifice (5) by forming a crimping edge (10e) constituted by the peripheral skirt (10c). <IMAGE>

Description

The subject of the present invention is a method of manufacturing a closure element known as a controlled opening for boxes, in particular of metal or various containers, and a closure element obtained by this method.

The present invention also relates to a box equipped with such a closure element.

The opening of a particularly metallic box often requires the use of a utensil of the can opener type, the implementation of which is sometimes dangerous and in any case difficult.

To avoid the use of a can opener, manufacturers have offered consumers various facilitated opening systems, the implementation of which requires, in principle, no tools, this is particularly the case for cans or cans so-called easy opening metal packaging.

Whatever the material constituting the box, all the various known opening systems have as an essential element an incision line surrounding a removable panel on which is fixed an opening ring provided with an incision spout, this is to say an element allowing to introduce a finger into it. The incision line determines a zone of least resistance of the cover, the incision spout is used to perforate the cover at the level of the incision line and the ring to tear off the removable panel "by force". The removable panel and the opening ring are assembled by welding or by a rivet stamped in the cover, introduced into said ring and mated thereon.

Generally, with this type of closing element of an easy-opening box, the opening gesture which consists in raising the ring to perforate the incision line, then draw it towards you to tear off the removable panel, makes the box unstable due to the spring effect resulting from the separation, often brutal, of the removable panel torn off "in force" and comprises risk of cutting your hand. Indeed, the separation of the removable panel from the rest of the closure element forms, along the incision line on the removable panel and the cover, a sharp edge which can cause cuts.

On the other hand, the formation of the incision line on the closure element must be carried out with precision in order to obtain a rigorous positioning of the incision spout relative to this line, which requires expensive tools.

In addition, given the opening movement and the presence of the incision line, it is necessary to provide stiffeners judiciously distributed over the closing element, which further complicates the tooling.

The object of the present invention is to avoid the abovementioned drawbacks and to provide packaging manufacturers and consumers with a closure element for an orifice which is easy to open, safe and without risk.

The present invention therefore relates to a method of manufacturing a closure element known as a controlled opening of a box, in particular a metal box, from a sheet blank, characterized in that the sheet blank is stamped to form a curved area, a curved area is formed from this curved area and a cut is made at this curved area to produce an orifice comprising a peripheral skirt, part of the peripheral skirt is widened and a removable cover is crimped onto the orifice, forming a crimping edge constituted by the peripheral skirt.

According to other characteristics of the invention:
- a part of the peripheral skirt of the orifice is enlarged by progressively flattening the previously curved removable cover, placed inside said skirt, the surface of the crimped cover being substantially identical to its surface before crimping and the perimeter of the crimped lid being greater than its perimeter before crimping,
- a part of the peripheral skirt of the orifice is widened by gradually flattening the cut-out constituting the removable cover, the surface of the crimped cut-out being substantially identical to its surface before crimping and the perimeter of the crimped cut-out being greater than its perimeter before crimping,
- a part of the peripheral skirt of the orifice is enlarged by progressively flattening an elastic washer, then a removable cover, previously formed and comprising a curved area, is placed inside said skirt, and the removable cover by forming a crimping edge constituted by the peripheral skirt,
- By widening the peripheral skirt of the shaped opening at said opening, a folded edge, keeping the perimeter of the orifice constant.

The present invention also relates to a closing element known as a controlled opening of a box, in particular a metallic box, characterized in that it comprises an orifice surrounded by a peripheral skirt. and at the level of which a removable cover is crimped, the crimping edge formed by the peripheral skirt being set back relative to the edge of the orifice.

According to other characteristics of the invention:
the removable cover consists of a previously formed patch, the surface of the cover after crimping being substantially identical to its surface before crimping and the perimeter of said cover after crimping being greater than its perimeter before crimping,
the removable cover consists of cutting the orifice, the surface of said cut after crimping being substantially identical to its surface before crimping and the perimeter of said cut after crimping being greater than its perimeter before crimping,
the removable cover consists of a patch comprising a curved zone, the perimeter of the cover being greater than the perimeter of the orifice,
- the cover comprises a ring,
- the crimping edge is placed inside the box,
- the crimping edge is placed outside the box,
- the outer fold of the crimping edge is rolled inward,
- the outside fold of the crimping edge is flat.

The present invention also relates to a box characterized in that it comprises an orifice with controlled opening produced by crimping an attached removable cover.

According to other characteristics of the invention:
- the crimping edge is set back from the edge of the orifice,
- the removable cover, after crimping, is larger than the orifice.

The present invention also relates to a beverage can having a removable crimped lid.

• - la Fig. 1 est une vue partielle en coupe d'une boîte munie d'un élément de fermeture selon l'invention.
• - les Figs 2 à 11 sont des vues schématiques en coupe montrant les différentes étapes de fabrica­tion de l'élément de fermeture selon la Fig. 1.
• - la Fig. 12 est une vue partielle en coupe d'une boîte munie d'un élément de fermeture selon un deuxième mode de réalisation.
• - les Figs. 13 à 16 sont des vues schémati­ques en coupe montrant les différentes étapes de fabrication de l'élément de fermeture selon la Fig. 12.
• - la Fig. 17 est une vue partielle en coupe d'une boîte munie d'un élément de fermeture selon l'invention et comportant un moyen d'extraction de l'opercule.

Other characteristics and advantages of the invention will appear on reading the description which follows, given by way of example and made with reference to the appended drawings.

• - Fig. 1 is a partial sectional view of a box provided with a closure element according to the invention.
• - Figs 2 to 11 are schematic sectional views showing the different stages of manufacturing the closure element according to Fig. 1.
• - Fig. 12 is a partial sectional view of a box provided with a closure element according to a second embodiment.
• - Figs. 13 to 16 are schematic sectional views showing the various stages of manufacture of the closure element according to FIG. 12.
• - Fig. 17 is a partial sectional view of a box provided with a closure element according to the invention and comprising a means of extracting the cover.

Referring first to FIG. 1, we see that the box has a body 1 which has at its upper part an opening 2 on the edge of which is crimped a designated closure element as a whole by reference 3.

This closing element 3 comprises an orifice 5 at the level of which is crimped a removable cover 4 which constitutes the detachable element of the box with controlled opening.

Referring now to Figs. 2 to 11 we will describe the different stages of manufacturing the closure element 3.

A blank 10 of identical shape to the opening 2 of the box and having a surface greater than said opening is cut from a metal strip, not shown, so as to be able to form the crimping edge on the body 1.

Then, various operations are carried out on the blank 10 to form the closing element 3. These various operations are carried out one after the other on a press comprising a succession of independent tools or a stepped tool.

For simplification, the device will be described as being constituted by a succession of independent tools in the description which follows.

First of all, the sheet blank 10 is placed in a first stamping tool (Figs. 2 and 3) comprising a base 11 forming a matrix which has an imprint 12 on its upper part.

The matrix can be independent of the base 11 and placed in a housing provided for this purpose inside said base.

On the other hand, the upper edge of the base 11, which surrounds the imprint 12 constitutes a lower peripheral blank holder 13.

Above the base 11, the first tool stamping comprises a body 14, the lower part of which constitutes an upper peripheral blank holder 15.

The body 14 includes a well 16 into which enters a punch 17, the upper face of which has a shape complementary to that of the cavity 12 of the matrix.

After placing the blank 10 on the lower peripheral blank holder 13, the upper peripheral blank holder 15 is first lowered so as to tighten the peripheral edge of the blank 10.

Then, descend the punch 17 so that its working face comes into contact with the blank 10 and forms a domed central zone 10a whose curve corresponds to the curve of the imprint 12 (Fig. 3).

Following this first phase, the blank 10 is turned over and placed in a second stamping tool (Figs. 4 and 5) comprising a base 20 which comprises a central cavity 21 in which is mounted a movable punch 22 provided on its upper face of a small flat 22a.

The movable punch 22 cooperates with a member 23 for regulating the movement of said punch which can be constituted for example by a spring so that in the rest position the upper face of the movable punch 22 is located above the upper face of the base. 20.

The second stamping tool also comprises a body 24 whose lower part constitutes an upper peripheral blank greenhouse 25. This body 24 comprises a well 26 in which slides a matrix 27 whose lower face is provided with an imprint 28 of complementary shape to that of the movable punch 22. The imprint 28 also includes a small flat 27a.

The blank 10 is placed on the upper face of the base 20 and the upper peripheral blank holder 25 is lowered first in order to tighten the peripheral edge of said blank. The matrix 27 is gradually lowered so that a portion of the convex zone 10a penetrates into the cavity 28 under the action of the movable punch 22 so as to form, from said convex zone 10a, a small curved zone 10b connecting to the rest of the blank 10 by a substantially vertical peripheral skirt 10c. The curved zone 10b has a flat 10′b.

During the descent of the die 27, the movable punch 22 also descends, which compresses the spring 23.

After this second phase, the blank 10 thus formed is once again turned over and placed in a punching tool (Figs. 6 to 8).

This punching tool comprises a matrix 30 comprising an imprint 31 of shape complementary to the curved shape (10b, 10c) formed on the blank 10 and in which a well 32 opens. The intersection between the imprint 31 and the well 32 forms a sharp edge 32a.

In this well 32 is slidably mounted a pusher 33.

The punching tool also comprises, in the axis of the well 32 and of shape complementary to said well, a punch 34 which has on its lower edge a cutting edge 34a.

The blank 10 is placed on the upper face of the matrix 30 in such a way that the curved zone (10b, 10c) comes to lodge in the cavity 31.

Then we gradually descend the punch 34 until its cutting edge 34a comes into contact with the curved area 10b, then straddles the cutting edge 32a (Fig. 7a) and makes an opening 5a in this curved area. The cut 10d thus formed separates from the rest of the blank 10 and falls on the pusher 33 (Fig. 7). The cutout 10d rests on the pusher 33 by means of its flat 10′b which will prevent the cutout from tipping over.

This cutout 10d, at this stage of the process, has the same dimensions as the opening 5a produced in the blank 10.

After reassembling the punch 34, the pusher 33 rises and passes the cutout 10d through the opening 5a to position said cutout above the edge of the curved area 10b, as shown in Fig.8.

The passage of the cutout 10d in the opening 5a takes place easily since at the time of punching said cutout tends to shrink slightly.

Then, down the punch 34 to slightly flatten the cutout 10d so that the edge of the cutout comes into contact with the skirt 10c and also the maintenance of said cutout at the time of transfer to the next tool.

According to a variant shown in FIG. 8a, maintaining the cutout 10d on the pusher 33 can be achieved by a stud 10g formed on said cutout and fitting into a housing 33a made on the pusher 33.

Then, the assembly constituted by the blank 10 and the blank 10d is transferred to a crimping tool (Figs. 9 to 11).

This crimping tool is constituted by an upper punch 40 and a lower pile 42, both being vertically movable so as to be able to approach one towards the other.

The upper punch 40 has a raised portion 41 of complementary shape to the skirt 10c formed in the blank 10. The pile 42 has a groove 43a which delimits a central portion 43 of complementary shape to the opening made in said blank. The groove 43a makes it possible to roll the end of the skirt 10c over the cutout 10d as will be described later.

The raised part 41 of the punch 40 enters the skirt 10c and blocks the edge of this skirt while the central part 43 of the pile 42 enters the opening 5a of the blank 10 as shown in FIG. 10.

In this position, the edge 10b is in abutment on the bottom of the groove 43a. On the other hand, the edge of the cutout 10d is supported on the raised part 41 and is positioned substantially at mid-height of the skirt 10c, while the bottom of said cutout 10d rests on the central part 43 of the punch. 42.

The bringing together of these two elements 40 and 42 progressively flattens the cutout 10d so that the edge of this cutout 10d causes this skirt 10c to buckle. This buckling is accentuated by the movement of the pile 42 which acts on the edge 10b (Fig. 10). At the same time, a folded edge 10f is formed at the orifice 5, the perimeter of the orifice 5 remaining constant.

At the end of the operation, the cutout 10d is completely flattened and crimped in the crimping fold 10th which is formed under the action of the punch 40 and the pile 42 as shown in FIG. 11.

The groove 43a rolls inward the outer edge of the crimping fold 10e so that the cutting edge of said fold is embedded in the cutout 10d which prevents oxidation of said edge.

In addition, the crimping edge 10e is set back from the folded edge 10f forming the orifice 5.

Thanks to the curved initial shape of the cutout 10d, the surface of this crimped cutout is substantially identical to its surface before crimping, but the perimeter of the crimped cutout is greater than its perimeter before crimping so that it can be pinched in folds during the crimping operation.

In this way, a closing element 3 is obtained which comprises a removable cover 4 set constituted by the cutout 10d itself and which suffices to crimp on the body 1 of the box (Fig. 1) to have a hyper closure. - waterproof.

The seal is produced, on the one hand, at the peripheral edge of the cover 4 and, on the other hand, at the edge of the crimping fold 10e.

According to a variant, the cover is not constituted by the cut 10d itself, but by a patch cut either in the metal strip where the blank 10 is cut, but in a different zone, or in another metal strip. In this case, the patch is previously formed to obtain a curve identical to the cut 10d and the crimping is carried out in the same manner as above.

According to another variant, the cover 4 can be formed from a material different from the blank 10 or a different color, then crimped, as previously with the edge of the orifice 5 formed in said blank. In this case, the cover also has the same surface and a curve identical to the cut 10d made in the blank.

According to yet another variant illustrated in FIG. 12, the cover 4 comprises a curved zone 4a, for example oriented towards the inside of the box 1.

In this case, the cover 4 is not constituted by the cutout 10d produced directly in the blank 10, as for the previous variant, due to the curved area 4a.

Indeed, taking into account the presence of this curved zone 4a on the cover 4, it is not possible to flatten this cover to obtain the widening of the skirt 10c.

This is why the cover 4 is constituted by a pellet cut either in the metal strip where the blank 10 is cut, but in a different area, or in another metal strip, and formed to obtain the curved area 4a. In this case, the cover 4 has a larger perimeter than the perimeter of the orifice 5.

Referring now to Figs. 13 to 16, we will describe the different stages of manufacturing the closure element according to FIG. 12.

The blank 10, in which the skirt 10c and the opening 5a have been previously produced, is placed in a forming tool (Figs. 13 and 14).

This tool is constituted by a lower punch 50 comprising an elastic washer 51 of shape complementary to the skirt 10c.

The tool comprises, on the other hand, an upper punch 52 comprising a raised portion 53 of shape complementary to the skirt 10c and penetrating into said skirt.

An element 54 forming a stop is placed at a certain distance and around the skirt 10c.

The approximation of the punches 50 and 52 causes the progressive flattening of the washer 51 which results in a widening of part of the skirt 10c. Simultaneously, a blank of a folded edge 10f is formed at the orifice 5, while keeping the perimeter of said orifice constant.

The widening of the skirt 10c can also be obtained by a cushion made of an elastomeric material which deforms under the action of a punch.

The element 5 limits the widening of the skirt 10c and contributes to the formation of the vertical edge of said skirt.

Then, the blank 10 thus formed is placed in a crimping tool identical to Figs. 9 to 11 comprising two punches 40 and 42 (Figs 15 and 16) and the cover 4, previously formed, is positioned in the skirt 10c.

The approximation of the punches 40 and 42 achieves the crimping of the cover 4.

During this operation, the folded edge 10f is flattened and, thanks to the groove 43a, the outer edge of the crimping fold 10e is rolled inward so that the cutting edge of said fold is embedded in the seal 4 to seal and prevent oxidation of said wafer.

The crimping edge 10e is also set back from the folded edge 10f.

Afterwards, it suffices to turn the closing element thus produced and crimp it onto the body of the box 1 so that the curved zone 4a of the cover 4 is oriented towards the inside of said box.

In this case, the cover 4 can also be formed from a material different from the plane 10 or from a different color.

To open the closing element 3 according to the embodiments described above, it suffices to press on the cover 4 which falls inside the box, thus avoiding having separable tablets towards the outside. from the box that often strews public places.

The control of the force necessary for the opening of the box is obtained during manufacture, by adjusting the crimping forces of the cover.

According to yet another embodiment illustrated in FIG. 17, the cover 4 may be provided with a ring 6 which is riveted or welded to the said cover making it possible to pull on this cover to open the box.

The closure element according to the invention has, among other things, the advantage of not having any accessible cutting edge capable of causing cuts when the box is opened and of ensuring food protection of the edge surrounding the orifice. in which the cover is set.

Furthermore, the cover may have all the desired dimensions, any shape, round, triangular, elliptical, adapted to each type of box and the closure element may include several crimped and detachable covers.

Finally, the removable cover can be produced on the body of the box or on the bottom of the box.

The invention applies to all cans, in particular metal cans, to various containers and for example to drink cans.

Claims (18)

1. A method of manufacturing a closure element (3) said to controlled opening of a particularly metallic box (1), from a sheet blank (10), characterized in that the blank is stamped sheet metal (10), to form a curved zone (10a), a curved zone (10b, 10C) is formed from this curved zone (10b) and a cut is made at this curved zone (10b, 10c) 10d) to produce an orifice (5) comprising a peripheral skirt (10c), a part of the peripheral skirt (10c) is widened and a removable cover (4) is crimped onto the orifice (5) by forming a crimping edge (10e) constituted by the peripheral skirt (10c). 2. Manufacturing method according to claim 1, characterized in that one widens a part of the peripheral skirt (10c) of the orifice by progressively flattening the removable cover (4) previously curved, placed inside said skirt, the surface of the crimped cover (4) being substantially identical to its surface before crimping and the perimeter of the crimped cover (4) being greater than its perimeter before crimping. 3. Manufacturing method according to claim 1, characterized in that a part of the peripheral skirt of the orifice (10c) is enlarged by progressively flattening the cutout (10d) constituting the removable cover (4), the surface of the crimped cutout (10d) being substantially identical to its surface before crimping and the perimeter of the crimped cutout (10d) being greater than its perimeter before crimping. 4. The manufacturing method according to claim 1, characterized in that one widens a part of the peripheral skirt (10c) of the orifice (5) by progressively flattening an elastic washer, then a removable cover (4) previously formed and comprising a curved zone (4a) is placed inside said skirt. crimp on the orifice (5) the removable cover (4) forming a crimping edge (10e) constituted by the peripheral skirt (10c). 5. Manufacturing process according to one of the preceding claims, characterized in that by widening the peripheral skirt (10c) of the opening (5), a folded edge (10f) is formed at said opening while maintaining the constant perimeter of the orifice (5). 6. Closing element known as a controlled opening of a box, in particular a metallic box (1), characterized in that it comprises an orifice (5) surrounded by a peripheral skirt (10c) and at the level of which a removable cover (4 ), the crimping edge (10e) formed by the periphery skirt (10c) being set back relative to the edge of the orifice (5). 7. Closing element according to claim 6, characterized in that the removable cover (4) is constituted by a previously formed patch, the surface of the cover (4) after crimping being substantially identical to its surface before crimping and the perimeter of said cover after crimping being greater than its perimeter before crimping. 8. Closure element according to claim 6, characterized in that the removable cover (4) consists of the cutout (10d) of the orifice (5), the surface of said cutout (10d) after crimping being substantially identical. on its surface before crimping and the perimeter of said cut after crimping being greater than its perimeter before crimping. 9. Closure element according to claim 6, characterized in that the removable cover (4) consists of a patch having a curved area (4a), the surface of said cover being greater than the surface of the orifice (5) . 10. Closing element according to one of claims 6 to 9, characterized in that the cover (4) comprises a ring (6). 11. Closing element according to claim 6, characterized in that the crimping edge (10a) is disposed inside the box (1). 12. Closing element according to claim 6, characterized in that the crimping edge (10e) is arranged outside the box (1). 13. Closing element according to claims 11 and 12, characterized in that the outer fold of the crimping edge (10e) is rolled inward. 14. Closing element according to claims 11 and 12, characterized in that the outer fold of the crimping edge (10e) is flat. 15. Box for applying the closure element according to any one of claims 6 to 14, characterized in that it comprises an orifice (5) with controlled opening produced by crimping a removable removable cover (4). 16. Box according to claim 15, characterized in that the crimping edge is recessed relative to the edge of the orifice (5). 17. Box according to claim 15, characterized in that the removable cover (4) after crimping is larger than the orifice (5). 18. Beverage box, for application of the closing element according to any one of claims 6 to 14, characterized in that it comprises a removable crimped cover (4).

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