FR2812278A1 - METHOD FOR PRODUCING A LID FOR CLOSING THE OPENING OF A CONTAINER - Google Patents

Abstract

The invention concerns a method for producing an inner seal in a sheet (4) of material constituting said seal (1), said seal (1) comprising a cover part (2) adapted to close the opening of a container and a tab-like part (3) adapted to be gripped and pulled to remove said seal (1). The method comprises steps which consist in cutting out the tab (3) and the cover part (2) in the sheet (4), and a step which consists in making holes (5) in said sheet (4), said holes being positioned so that the cut-outs (6, 8) of the tab (3) and the cover part (2) are urged to emerge therein, so as to prevent any incipient rupture when the seal is being removed (1) from the opening of said container by action exerted on the tab (3).

Description

I The invention relates to a method of producing a cover intended for

  closing the opening of a container, such a cover, an assembly comprising such a cover and a container, in particular a container filled at least partially

  of content, as well as a machine for implementing the method.

  Lids are already known which are intended to close the opening of containers, in order to

  in particular to guarantee the conservation of the contents of these containers.

  These lids are generally in the form of a thin sheet of material such as, for example, aluminum.

  Such a cover is generally secured to the edge of the opening of the

container, in particular by welding.

  There are several ways to clear the opening of the sealed container, in particular the perforation of the cover and the peel, that is to say the separation of the cover from the rim of the opening of the container with which it is associated. , And this

  by an external action, notably manual.

  In the case of a peel cap, this most often comprises, in addition to a part intended to close the opening of the container, hereinafter called "cover part", a tongue, produced in the same sheet of material that

  said cover part, therefore in one piece with it.

  This tongue, which extends the cover part of the cover, is in principle narrower than said cover part. The width of this tongue is however large enough to give it sufficient strength

  during the separation operation of the cover, as described below.

  When the cover is secured to the rim of the container opening, the tongue is folded over the accessible (or external) face of the cover. The dimensions of the tongue are such that in the folded position said tongue does not exceed the outline of the opening of the container. In this way, it is possible to place a cap on the sealed opening of the container without

damage the tongue.

  In order to separate the cover from the flange with which it is associated, a user unfolds at least partially the tongue then exerts a pulling force on

  this, which allows, with sufficient effort, to separate the cover.

  The width of the tongue is large enough so that there is no risk of rupture of this tongue when the user exerts a pulling force on

it.

  In the prior art, the method for producing such a tab seal comprises in particular two successive cutting steps: firstly, using a first tool, the tongue is cut out, from a sheet of material constituting said cover ; - in a second step, and after having folded the said tab a half turn along a fold line joining the ends of the cut-out of the tab, it is cut from the same sheet of material, and thanks to a

  second tool, the cover part of the cover.

  In one embodiment, the sheet of material is in the form of a strip initially wound on a reel. For the implementation of the method, the strip is made to pass so that it passes through two cutting stations, making the two abovementioned cuts in said sheet. The strip is first stopped at a first station, where the implementation of the first tool makes it possible to cut the tongue, then the strip is driven to a second station, where it is stopped so that the implementation of the second tool

  allows to cut the cover part.

  The junction between the two cutouts must ensure good transmission of forces between the tongue and the cover part during the

  pull the tab by the user.

  Indeed, a bad junction between these two cuts would generate zones which would be the seat of stress concentrations during peeling, which could

  lead to a rupture of the seal.

  Due to the existence of two successive cutting tools for the production of the cover, there is a risk of discrepancy between the two tools, therefore of

  offset between the two corresponding cuts.

  This offset leads to a deterioration of the connection between the two cuts.

  This is all the more critical as this poor quality connection is located in the vicinity of the fold line between the tongue and the cover portion of

  the cap. The risk of breakage during peeling is therefore increased.

  This problem is all the more crucial that the cover is heat sealed on the container, that the tab is folded over the cover part, the

  heat sealing having been carried out by induction.

  The object of the invention is to remedy these drawbacks.

  To this end, and according to a first aspect, the invention proposes a method of producing a cover - intended to be removed - in a sheet of material constituting said cover, said cover comprising a cover part intended to close the opening. of a container and a tongue-shaped part intended to be grasped and pulled in order to remove said cover, the method comprising the steps consisting in cutting the tongue and the part of

cover in said sheet.

  This method is characterized in that it also comprises a preliminary step consisting in making holes in said sheet, these holes being positioned so that the cutouts of the tongue and of the cover part come to open therein, so as to prevent any initiation of rupture during the operation of removing the cover from the opening of said container by action on the tongue. According to the invention, the method is such that the cutting of the cover part, the cutting of the tongue and at least part of the outline of the holes are

  substantially "tangent", as defined below.

  Thanks to the fact that these cutouts open into the holes, a substantial clearance is accepted between the cutout of the cover part and the cutout of the tongue. The method further comprises a step of folding the tongue of the cover, so as to fold said tongue over the cover part, this

  step being carried out after the step of cutting the tongue.

  According to a second aspect, the invention relates to a cover obtained by this method, the cover being such that the outline of the cover formed by cutting the tongue, the cutting of the cover part and the outline of the holes does not

  has no primer or area conducive to failure.

  Preferably, the cover is made of aluminum foil or based on aluminum. Preferably also, the cover part of said cover is

noticeably discoid.

  According to a third aspect, the invention relates to an assembly comprising a container comprising an opening, and a cover as just described,

  intended to close said opening.

  According to a fourth aspect, the invention relates to an assembly comprising an empty container or at least partially filled with a certain content and comprising an opening, and a cover as just described, intended for

close said opening.

  Finally, according to a last aspect, the invention relates to a machine for implementing the method according to the invention, said machine successively comprising - means for feeding and moving a sheet of material constituting said cover; - a first tool intended to cut the tab of the cover; - a tool intended to bend the tongue; - a second tool intended to cut the covering part of the cover, this machine also comprising a tool intended to make holes in

  said sheet, this tool being placed upstream of the first tool.

  The other characteristics of the invention will emerge from the description which follows,

  with reference to the accompanying drawings in which: - Figure 1 is a top view of a cover of the prior art flat and i5 unfolded; - Figure 2 is a partial enlargement of Figure 1; - Figures 3a, 3b, 3c, 3d are schematic representations respectively of the first, the second, the third and the fourth step of the method of producing a seal according to the invention; - Figure 4 is a top view of a cover according to the invention flat and unfolded; - Figure 5 is a partial enlargement of Figure 4; - Figure 6 is a detail view of a cover according to the invention flat and unfolded; - Figure 7 is a schematic representation of a machine for setting

  implementing the method according to the invention.

  A cover 1 according to the invention, as illustrated in FIG. 4, comprises - a cover part 2, intended to close the opening of a container (not shown), such as a bottle for example; - a tongue-shaped part 3, allowing a user to remove

  the cover 1 of the opening of said container.

  According to a variant embodiment not shown, the cover 1 comprises

  several tongue-shaped parts 3.

  Such a cover 1 is produced from a sheet 4 of material constituting said cover. It may for example be aluminum or equivalent, or an aluminum-based material. The sheet 4 used to make the cover can also

  have several layers of different materials.

  The cover 1 can also be produced in a plastic film, or in a multilayer complex comprising in particular a plastic film. However, the invention takes on its full usefulness when the material used is easily torn, as is the case with aluminum. In addition, a cover intended to be heat-sealed by induction is necessarily made of aluminum. Preferably, the thickness of the sheet 4 is relatively small, of the order of

  0.15 to 0.30 mm, for example 0.20 mm.

  This cover 1 is intended to close the opening of a container, such as typically a bottle containing for example food products.

liquids or pasty.

  The dimensions of the covering part 2 of the cover 1 are generally slightly greater than the dimensions of the opening of the container, so that

  said opening is completely covered by said cover 1.

  Generally, the cover 1 is secured to the rim of the opening of the container, by ultrasonic welding or by heat sealing for example, and very particularly by induction heat sealing, while the tongue 3 is

  folded over the cover part 2.

  The edges of the cover part 2 of the cover 1 which protrude around the opening of the container are then folded around said opening,

  especially for aesthetic reasons.

  The cover 1 shown is such that the cover part 2 is discoidal.

  However, this form is not limiting. It may for example be a polygon or any other shape adapting to the shape of the opening of the corresponding container. The tongue 3 of the cover 1 is made in the same sheet 4 as the cover part 2, in extension of the latter, and separated from it by a

fold line 7.

  The tongue 3 has an oblong shape, its length and its width being such that, when it is folded over the cover part 2 along the fold line 7, the

  tongue does not protrude from the outline of the cover part 2.

  Indeed, when the lid 1 is secured to the edge of the opening of the container,

  the tongue 3 is folded over the accessible (or external) face of the cover 1.

  The fact that the dimensions of the tongue 3 are smaller than the dimensions of the cover part 2 thus make it possible to place a plug on the opening

  container without risk of damaging the tongue 3.

  The dimensions of the cover 1 shown in Figure 4, which corresponds to a typical application, are as follows: - diameter of the cover part 2: 34 mm; - tongue width: 7 mm;

  - length of the tongue: 8 mm approximately.

  These dimensions are of course given by way of nonlimiting example.

  Those skilled in the art will understand in particular that the length of the tongue 3 must be sufficient for a user to be able to grasp it with the fingers in order to pull it so as to separate the cover 1. The width of said tongue 3 in front by elsewhere be sufficient so that it does not break during the

separation of the cover 1.

  On the other hand, the diameter of the cover part is more generally

between 10 and 100 mm.

  FIG. 4 represents the cover 1 "flat", the tongue 3 not being folded over the cover part 2 but unfolded in extension, this in order to illustrate

  the main characteristic of the cover 1 of the invention, as described.

  The cover 1 may be temporarily in this configuration, during the operation of removing said cover 1 from the rim of the opening of the container.

with which it is associated.

  However, when the cover 1 closes the opening of a container, the tongue 3 is completely folded, and when the cover 1 is being removed by a

  user, the tongue 3 is generally only partially unfolded.

  The process for producing the seal 1 according to the invention is described, in

  reference to Figures 3a to 3d and 7.

  During the first step of the manufacturing process of the seal 1, we realize

  two holes 5 in the sheet 4, as shown in Figure 3a.

  The function of the holes 5 is to allow a cover 1 to be created by cutting.

  the outline of which does not include a breaking point.

  Indeed, the holes 5 are such that the contour of the cover 1 in the vicinity of the fold line 7 of the tongue 3 comprises three successive parts: - the cutout 6 of the tongue 3; - the outline 9 of a hole 5; - the cutout 8 of the cover part 2, these three cutouts which make it possible to produce said cover 1 forming a line

  showing no abrupt change in curvature.

  Preferably, these three cuts are substantially tangent to each other, and this despite the slight possible offset of the tools 17, 18, 20 used for the

  achieve. In the description, the term "tangent" is used to describe

  generally the characteristic that the three cutouts form a

  line showing no abrupt change in curvature.

  In the embodiment shown, the holes 5 are circular.

  In other embodiments not shown, the holes 5 are oval in shape. However, it is understood that the holes can also have another shape

  suitable for their function, this shape comprising at least one curved part.

  We will place ourselves in the following description in the particular case where the holes

are circular.

  The diameter and the relative position of the holes 5 are a function of the size of the tongue 3 and of the cover part 2, in order to guarantee that the outline of said

  lid 1 does not have a breaking point.

  Consequently, the distance between these two holes 5 is substantially equal to the width of the tongue 3, while their radius is such that at least part of the contour 9 of each of the two holes 5 is substantially tangent on the one hand to the

  contour of the tongue 3 and on the other hand the contour of the cover part 2.

  In the embodiment shown in the accompanying figures, the holes 5 have a diameter between 3.5 and 4.5 mm, and preferably of the order of 4 mm. It is understood that, when the cover 1 comprises several tabs 3, we

  make several pairs of holes such as 5.

  In a second step of the process for manufacturing the cover 1, as illustrated in FIG. 3b, the tongue 3 is cut from the sheet 4, using

  of a first tool 18 (see FIG. 7).

  The first tool 18 is adjusted so that the two ends 6a, 6b of the cutout 6 of the tongue 3 each open into one of the two holes 5 made in the previous step. Preferably, each of the end parts of this cut 6 is substantially tangent to the contour 9 of one of the two holes 5. The term "end parts" means each of the portions of the cut 6 located in the vicinity of each of the ends 6a, 6b of said

cutout 6.

  FIG. 3c illustrates the third step of the method, during which the tongue 3 is folded by half a turn on the sheet 4, along a fold line 7 connecting

  substantially the two ends 6a, 6b of the cutout 6 of the tongue 3.

  The fourth step of the process (FIG. 3d) consists in cutting out the cover part 2 of the cover 1 from the sheet 4, using a second tool 20 (see

figure 7).

  Similarly to the cutout 6 of the tongue 3, the two ends of the cutout 8 of the cover part 2 are such that they each open out.

  in one of the two holes 5 made during the first step.

  Preferably, each of the end portions of this cutout 8 is substantially tangent to the contour 9 of one of the two holes 5. The term "end portions" means each of the portions of the cutout 8 located in the vicinity

  of each of the ends of said cutout 8.

  In this way, the cutout 8 of the cover part 2, the cutout 6 of the tongue 3 and at least part of the outline 9 of the holes 5 are substantially tangent, as defined above, which makes it possible to avoid any initiation or any area liable to rupture during the removal operation

  the cover 1 of the opening of the container by action on the tongue 3.

  We will now describe more precisely the improvements made by the lid 1 of the invention, with reference to FIGS. 4, 5 and 6, compared with the

  lids of the prior art, as illustrated in FIGS. 1 and 2.

  In the five figures 1, 2, 4, 5 and 6, the solid line defines the theoretical contour of the cover, while the mixed lines represent the actual outline of the cover II when the cutting tools 17, 18, 20 are slightly offset from each other

  compared to others, following a disruption of the machine used.

  The result of the process for producing the cover 1 according to the invention will be described in relation to FIGS. 5 and 6, which are enlarged views of the junction zone between the cutout 6 of the tongue 3 and the cutout 8 of part of

cover 2.

  The contour of the cover 1 in the vicinity of the fold line 7 of the tongue 3 comprises three successive parts: - the cutout 6 of the tongue 3; - the outline 9 of a circular hole 5;

  - the cutout 8 of the cover part 2.

  As illustrated in FIG. 6, these three cutouts 6, 8, 9 are such that the cutout 6 of the tongue 3 and the cutout 8 of the cover part 2

open into the holes 5.

  Preferably, these three cutouts 6, 8, 9 are substantially tangent, so as to form a line having no abrupt variation in curvature. In particular, at the fold line 7 of the tongue 3, the contour of the cover 1 corresponds to a portion of the contour 9 of one of the two holes 5, so that there is no zone of fragility which could lead to tearing

of cover 1 during peeling.

  In FIG. 6, this case is represented by the solid line, and corresponds to an optimal adjustment of the successive tools 17, 18, 20 for producing the cover 1, leading to an optimal position of the holes 5 relative to the cutouts 6 and 8

  of the tongue 3 and of the cover part 2 respectively.

  A certain offset of the tool 17 making it possible to make the holes 5 relative to

  to the other tools 18, 20 is however acceptable.

  Indeed, this tool offset leads to an offset of the "theoretical" outline 9 of the holes 5, towards a "real" outline 9 'of the holes 5, represented in phantom

in figure 6.

  In the latter case, the cutouts 6, 8 always open into the holes 5. Small variations in the curvature of the outline of the cover 1 then appear, but they remain small enough so as not to risk generating the

  tear in seal 1 during peeling. By the way, these areas of weakness -

  relative - are located outside the critical zone of the fold line 7, and

  -10 are therefore less risky than for the lids of the prior art.

  In the case where the two tools 18, 20 for cutting the tongue 3 and the cover part 2 are offset relative to one another, following a disruption of the machine, the actual shape of the cover 1 is slightly modified (broken line representation in FIG. 5), the cutout 8 'of the cover part 2 being offset with respect to the cutout 6 of the

tab 3.

  In the prior art (illustrated in FIG. 2, which is an enlarged view of the junction zone between the cutout 6 of the tongue 3 and the cutout 8 of the cover part 2 of the cover 1 of the figure), this offset induces a sudden variation in the curvature of the contour at the point of intersection 10 between these two cuts 6, 8 '. In addition, this point of intersection10 is located in the close vicinity of the fold line 7 of the tongue 3, which weakens all the more

this zone.

  Consequently, with this configuration of the prior art, the risks of

  rupture of the seal at the time of peeling are high.

  On the contrary, the cover 1 according to the invention does not have this drawback. In fact, as shown in FIG. 5, an offset of one of the cutting tools 17, 18, 20 does not lead to the creation of a sudden breaking point of the

  curvature of the lid 1.

  The cutout 8 'of the cover part 2, following a disruption of the

  machine used, always leads into hole 5.

  In this way, there is therefore no critical point, in the vicinity of the fold line 7, which can generate a tear initiation, or an area suitable for tearing. Thanks to the invention, any primer or zone suitable for tearing due to a defect in cutting the cover following a disruption of the machine used is io on the one hand very significantly reduced, and on the other hand displaced out of the

  critical folding and joining area.

  Thanks to the production method according to the invention, we can therefore accept a substantial clearance between the cutout 8, 8 'of the cover part 2 and the cutout 6 of the tongue 3, and this thanks to the fact that these cutouts 6 , 8, 8 'lead into

the holes 5.

  According to another aspect, the invention relates to a possible machine for setting

  implementing the method as just described.

  As illustrated in FIG. 7, the machine comprises first means of winding 10 of the sheet 4 of material constituting the cover 1, this sheet 4 being in the form of a strip initially wound on

  said first winding means 10.

  These first winding means 10 can be presented for example under

  the shape of a mobile cylinder rotating around a horizontal axis.

  For the implementation of the process, the sheet 4 is progressively unwound and it is scrolled so that it passes successively through each of the stations corresponding to the different stages of the process. The arrows in figure 7

  indicate the direction of movement of this sheet 4.

  The sheet 4 thus passes into at least four successive stations 11, 12, 13 and 14, the sheet 4 being stopped successively at each of these stations 11, 12, 13 and 14 so that the step of the process for carrying out the process is carried out. 'corresponding cover 1. The machine thus comprises: a first station 11, which corresponds to the first stage during which the holes 5 are made in the sheet 4; - A second station 12, which corresponds to the step during which is 1o made the cutout 6 of the tongue 3 of the cover 1; - A third station 13, which corresponds to the step during which the tongue 3 is folded back half a turn on the sheet 4 along the fold line 7; a fourth station 14, which corresponds to the stage during which is

  cut 8 of the cover part 2 of the cover 1.

  Each of these stations 11, 12, 13, 14 is associated with a tool, respectively 17,

  18, 19 and 20, allowing the corresponding operation to be carried out.

  In the fourth station 14, a plug 21 is, before the cutout 8 is produced, presented under the tool 20, and under the sheet 4. The tool 20, which is for example in the form of a punch cutting, then cut 8 of the cover part 2 and, in the same movement, place

  the cover 1 thus entirely cut at the bottom of the plug 21.

  In general, the plug 21 is provided with a skirt on the internal face of which there is a thread intended to cooperate with a complementary thread located

  on the neck of the container, the opening of which is intended to be closed by the seal 1.

  The installation of the cover 1 at the bottom of the plug 21 by the tool 20 therefore requires a certain effort to overcome the resistance to movement of the cover 1

  towards the bottom of said plug 21 due to the thread of the skirt of plug 21.

  The presence of this thread on the skirt of the plug 21 allows the cover 1 to be held at the bottom of the plug 21, once the said cover 1 has been placed at the

bottom of the cap 21.

  The cap 21 - cover 1 assembly can thus be stored in a container 15, before being screwed onto the neck of a container. This intermediate storage operation may not exist, the plugs 21, each provided with a cover 1

  being directly directed to a positioning station on containers.

  The sealing of the cover 1 at the rim of the opening of a container takes place in particular as follows: once the stopper 21, at the bottom of which is a cover 1, screwed onto the neck of the container, there is presented the neck of said container near an induction head. The energy is focused at the level of the contact zone between the cover and the rim of the opening of said container, this

  which generates the desired solidarity.

  The sheet 4, in which there are now orifices corresponding to the cut-out lids, is then wound on second winding means 16, which can be similar to the first means

winding 10.

  The sheet 4 at the outlet of the machine can then be used in other

applications or recycled.

Claims (10)

  1. Method for producing a cover (1) intended to be removed from a sheet (4) of material constituting said cover (1), said cover (1) comprising a cover part (2) intended to close the opening of a container and a tongue-shaped part (3) intended to be grasped and pulled in order to remove said cover (1), the method comprising the steps consisting in cutting out the tongue (3) and the covering part ( 2) in said sheet (4), characterized in that it also comprises a prior step consisting in making holes (5) in said sheet (4), these holes being positioned so that the cutouts (6, 8, 8 ') of the tongue (3) and of the cover part (2) come out therein, so as to prevent any initiation of rupture during the removal operation of   the cover (1) of the opening of said container by action on the tongue (3).   2. Method according to claim 1, characterized in that the cutout (8, 8 ') of the cover part (2), the cutout (6) of the tongue (3) and at least   part of the outline (9, 9 ') of the holes (5) are substantially tangent.   3. Method according to claim 1 or 2, characterized in that one accepts a substantial clearance between the cutout (8, 8 ') of the cover part (2) and the cutout (6) of the tongue (3) , thanks to the fact that these cutouts (6, 8, 8 ') open into the holes (5).   4. Method according to any one of claims 1 to 3, characterized in that   that it further comprises a step of folding the tongue (3) of the cover (1), so as to fold down said tongue (3) on the cover part (2),   this step being carried out after the step of cutting the tongue (3).   5. Method according to any one of claims 1 to 4, characterized in that   that the diameter of the holes (5) is of the order of 3.5 to 4.5 mm, in particular close to 4 mm.   6. Lid obtained by the method according to any one of claims   1 to 5, characterized in that the contour of the cover (1) formed by the cutout (6) of the tongue (3), the cutout (8, 8 ') of the cover part (2) and the outline (9, 9 ') holes (5) does not have a primer or area conducive to rupture. 7. Lid according to claim 6, characterized in that the material   constituting said cover (1) is based on aluminum.   lo 8. Cover according to claim 6 or 7, characterized in that the thickness of said cover (1) is of the order of 0.15 to 0.30 mm, in particular close to 0.20 mm.   9. Lid according to any one of claims 6 to 8, characterized in that   that the cover part (2) of said cover (1) is substantially discoidal. 10. Cover according to claim 9, characterized in that the cover part (2) of said cover (1) has a diameter between 10 and 100 mm, especially around 35 mm.   11il. Assembly comprising a container having an opening, and a   cover (1) according to any one of claims 6 to 10, said   cover (1) being intended to close said opening.   12. Assembly comprising a container at least partially filled with a certain content and comprising an opening, and a cover (1) according to one   any one of claims 6 to 10, said cover (1) being intended to close said opening.   13. An assembly according to claim 11 or 12, characterized in that the cover (1) is thermally welded by induction on the rim of the opening of the container, while the tongue (3) is folded over the outer face   accessible from the cover part (2).   14. An assembly according to any one of claims 11 to 13, characterized   in that the dimensions of the cover part (2) of the cover (1) are slightly greater than the dimensions of the opening of the container, so that said opening is completely covered, and in that the edges of said cover part (2) is folded around said opening. 15. Machine for implementing the method according to any one of   Claims 1 to 5, said machine comprising successively:   1o - means for supplying and scrolling a sheet (4) of material constituting said cover (1); - a first tool (18) intended to cut the tongue (3) of the cover (1); - a tool (19) intended to bend the tongue (3); - a second tool (20) intended to cut the cover part (2) of the cover (1); characterized in that it also comprises a tool (17) intended for   make holes in said sheet (4).