EP0062571B1 - Process and device for piercing the lid of a recipient, and manufacturing appliance for the device - Google Patents

Description

The invention relates to a method for providing lids for receptacles with lever tabs for piercing, said lids being made of a flexible and tearable material.

Many lid opening devices are known.

Thus, it has been proposed to cover pre-embrittlement with an element which is grasped and which is pulled to cause the rupture of the cover along its lines of embrittlement. This opening system is generally inconvenient and requires a pre-impression which is not compatible with the conservation of certain products (oxidation and / or bacteriological contamination at the bottom of the pre-imprint lines, for example when the bottom of the pre-imprint reaches a oxidizable and / or sterile layer of a multilayer lid sterilized on the surface).

Another solution has been proposed, consisting of preforming a hole in the cover and covering it with an adhesive element which is easy to remove. However, this system has also not been satisfactory with regard to the conservation guarantees for certain products.

A peelable cover device has been very well received by manufacturers and users. Generally associated with an installation for manufacturing thermoformed containers, it has led to a safe and economical opening system.

However, there are products for which the latter solution cannot be used, in particular in the case of long-term or sterile packaging requiring perfect sealing at the level of the lid which can only be obtained with sealing by autogenous welding, therefore not peelable.

French patent 2 241 466 also discloses cover opening devices using lever-piercing tabs, but on the one hand, these tabs are glued directly flat on relatively rigid covers made of material. thermoplastic, and secondly, these opening devices are necessarily associated with a cover having weakening lines and operate the opening more by shearing at the weakening lines than by actual drilling of the cover. Furthermore, it is advisable to position the tongues in a very precise position relative to the weakening lines, which is not always easy and compatible with a high production rate.

The invention aims to propose a new type of simple and economical opening method and device, which can be adapted to many types of lid and in particular to those generally used in equipment for manufacturing and packaging thermoformed containers with lids. welded which are cut from cover strips, and not having the aforementioned drawbacks. The manufacturing and packaging equipment particularly targeted are of the so-called F.F.S. (abbreviated designation of three significant English verbs: form, fill, seal).

The objects of the invention are achieved by means of a method for providing container lids with piercing tongues by lever effect, said lids being made of a tearable material, a method according to which substantially flat rigid tongues are produced which are fixed on the covers so as to divide them into a drilling arm and an operating arm, characterized in that the tongues are cut from a rigid thermoplastic strip used for the manufacture of thermoformed containers which, after filling with a product, are closed by a flexible and tearable cover made from a strip with a cover superimposed on the thermoplastic strip comprising the receptacles, which a hinge pin is produced on each tongue, which the cut tabs are transferred to the corresponding covers, and then each tongue is fixed by its hinge pin to one of the corresponding covers when these are in the position of closure on containers.

The invention also relates to a device for piercing the lid of containers by leverage, known from FR-A-2241466, of the type comprising a rigid tongue that is substantially planar, this lid being made of a flexible and tearable material, and the rigid tongue being provided with a hinge pin which divides it into a drilling arm and an operating arm and which is fixed to the cover.

According to a first embodiment, the invention provides that the articulation axis is constituted by a rib of the tongue.

According to a second embodiment, the invention provides that the device comprises a second flexible tongue having at least approximately the same extension as the rigid tongue and fixed, on one side to the drilling arm of the rigid tongue and, from the 'other side, at least in the area covered by the operating arm of the rigid tongue, on the cover.

The invention also relates to an installation for manufacturing a device for piercing a container lid by leverage, this lid being made of a flexible and tearable material, characterized in that it is associated with packaging equipment of the type which thermoforms containers from a rigid thermoplastic strip, which fills them with a product and which seals them with a flexible strip with a cover and which finally cuts the sealed containers from the thermoplastic strip and the cover strip and that comprises means for cutting substantially flat rigid tongues in the thermoplastic strip, means for providing the tongues with a hinge pin dividing the tongues into a drilling arm and an operating arm, means for transferring the loose tongues from the place of their cutting to the place of their attachment to the corresponding lids and means for fixing said hinge pins on the lids of the containers.

Thus, when using the piercing device, manual lifting of the operating arm initially causes the tongue to tilt around the articulation axis and the cover to be pierced by the piercing arm, and , in a second step, the tearing of part of the cover from the hole.

Thanks to the device according to the invention, it is entirely possible to dispense with a pre-impression. Naturally, it can however be used, especially when one wishes to obtain a tear along a given line or when the cover is particularly thick.

The opening system according to the invention has, apart from its simplicity, other advantages; it does not require a strong and / or sudden movement (which can lead to the product contained in the container being spilled); if the tab is slightly pulled, the container can be closed temporarily by putting it back in position; since the tongue can be pulled out and remain attached to the partially torn cover, a separate pollution-generating element is not created when it is thrown away.

Advantageously, in the first embodiment, the rib is formed integrally with the tongue. More precisely, the rib is formed by a deformation of the tongue obtained for example by stamping.

Advantageously, the tongue is based on rigid plastic material, and in particular on the plastic material constituting the container itself.

In the context of the manufacture of thermoformed containers from a thermoplastic strip provided with a welded and cut cover, it is advantageous to form the piercing tabs in the thermoplastic strip used to make the containers.

Advantageously, the tongues are cut from the thermoplastic strip in the free zones situated between the zones for forming the containers.

Advantageously, the tabs are cut when the containers are cut.

Thanks to the second embodiment, the axis of articulation of the rigid tongue on the cover is produced by the line of separation between the part of the flexible tongue, part fixed on the rigid tongue, and the part of the flexible flexible tongue by compared to said rigid tongue but fixed on the cover. By tilting upwards the operating arm of the rigid tongue, the drilling arm of the latter necessarily pivots downwards by tearing the cover at this point up to the line of articulation. Then by pulling the rigid tab towards the rear end of the flexible tab integral with the cover, the cover is torn at the same time along lines following at least approximately the edges of the flexible tab. Thus, also in this embodiment, it is not necessary to provide the cover with weakening or tearing lines.

For fixing the flexible tongue to the rigid tongue and / or to the cover, a hot glue or a lacquer or a fusible varnish or other sticky substance is generally used.

Although the cover can be made of any tearable material, it is advantageous to make it out of a metal sheet, in particular of aluminum, provided if necessary with a heat-bonding film.

The rigid tongue and the flexible tongue can be made of any suitable material, but when the containers are produced from a thermoplastic sheet and the cover from an aluminum strip, if necessary provided with a film. iron-on, it is advantageous to manufacture the rigid tabs from the thermoplastic strip and the flexible tabs from the aluminum strip.

In this case, it is recommended to use for the manufacture of the rigid tongues and flexible tongues the zones of thermoplastic strip and of aluminum strip situated between the curvilinear or rounded edges of the thermoplastic receptacles when cutting the receptacles from the strip. container and lids strip.

For this purpose, it is possible at the time of sealing the cover strip on the edges of the filled containers and still attached to the thermoplastic container strip, seal part of the cover strip, part corresponding to that of the flexible tab, intended to be fixed on the rigid tongue and then, preferably, after advancing the sealed containers by at least one step, the rigid and flexible tongues are cut together in the areas often in the form of stars, lying between the edges of the containers which at this time are not yet or are only partially cut from the container strip / cover strip assembly, the cutting zone of the rigid and flexible overlapping tabs being chosen so that it coincides with the zone of preliminary sealing which must then correspond to the piercing arm of the cut rigid tongue. Of course, the cut and sealed assemblies of the rigid and flexible tongues are recovered and the entire face of the flexible tongue, face turned away from the rigid tongue, is preferably glued to the lid of a sealed container in the zone located at the plumb with the opening of a container. Preferably, the flexible tongue is glued to the cover - which is made of the same material as the latter - so that the piercing arm of the rigid tongue is located near the edge and, if necessary, near a corner of the container opening.

To ensure bonding of the flexible tab on the cover, the external free face of the latter can be glued with an appropriate glue and then apply the rigid tongue-flexible tab assembly with the glued side against the corresponding cover but it is also possible to glue the cover area intended to receive the free face of the flexible tongue which on its other face adheres firmly to the drilling arm of the rigid tongue.

An installation for manufacturing this piercing device, having a flexible tab and a rigid tab superimposed, comprises in particular means for sealing the flexible strip with cover on the rigid strip inside the free areas between the containers in corresponding areas subsequently to the drilling arms of the various rigid tabs, means for cutting sets of rigid and flexible tabs superimposed, means for transferring the cut and sealed sets of rigid and flexible tabs between the cutting station and the place where they are placed in place on the lids of the sealed containers, means of gluing either of the free face of the flexible tab or of the lid zone intended to receive the set of rigid and flexible tabs, as well as means of applying the sets rigid and flexible tabs on the corresponding covers, so that the free face of the flexible tab adheres firmly to the cover at least in the area covered by the operating arm of the rigid tongue.

• - la figure 1 est une vue en plan d'un récipient et de son couvercle muni d'un premier mode de réalisation du dispositif de perçage de l'invention;
• - la figure 2 est une vue de face du récipient de la figure 1;
• - la figure 3 est un détail agrandi du dispositif de la figure 2;
• - la figure 4 est une vue en plan récipients formés dans une bande thermoplastique et montrant l'emplacement de découpe des languettes du premier mode de réalisation du dispositif;
• - la figure 5 est un détail agrandi de la figure 4;
• - la figure 6 est une vue schématique latérale partielle d'une installation de fabrication du premier mode de réalisation du dispositif de l'invention;
• - la figure 7 représente une pince élastique utilisée dans l'installation de la figure 6;
• - la figure 8 est une vue en coupe verticale à travers un récipient dont le couvercle est muni d'un second mode de réalisation de dispositif de perçage de l'invention;
• - la figure 9 est une vue agrandie du dispositif de la figure 8 mais en position de perçage;
• _ la figure 10 est une vue en plan d'une bande à couvercles scellée à une bande thermoplastique à récipients, cette figure montrant à la fois les contours de découpe des récipients et des languettes, dans le cadre du second mode de réalisation de l'invention;
• - la figure 11 est une vue schématique latérale d'une installation de fabrication du second mode de réalisation du dispositif de perçage de l'invention;
• - la figure 12 est une vue de dessus de l'installation de la figure 11.

The invention will be better understood from the description which follows, given with reference to the accompanying drawings in which:

• - Figure 1 is a plan view of a container and its cover provided with a first embodiment of the piercing device of the invention;
• - Figure 2 is a front view of the container of Figure 1;
• - Figure 3 is an enlarged detail of the device of Figure 2;
• - Figure 4 is a plan view of containers formed in a thermoplastic strip and showing the location for cutting the tabs of the first embodiment of the device;
• - Figure 5 is an enlarged detail of Figure 4;
• - Figure 6 is a partial side schematic view of a manufacturing installation of the first embodiment of the device of the invention;
• - Figure 7 shows an elastic clamp used in the installation of Figure 6;
• - Figure 8 is a vertical sectional view through a container whose cover is provided with a second embodiment of the piercing device of the invention;
• - Figure 9 is an enlarged view of the device of Figure 8 but in the drilling position;
• _ FIG. 10 is a plan view of a strip with lids sealed to a thermoplastic strip with containers, this figure showing both the cutting contours of the containers and of the tongues, in the context of the second embodiment of the invention;
• - Figure 11 is a schematic side view of a manufacturing installation of the second embodiment of the drilling device of the invention;
• - Figure 12 is a top view of the installation of Figure 11.

The first embodiment of the drilling device of the invention (Figures 1 to 7) comprises a tongue 1 substantially planar provided with a hinge pin 2 in the form of a rib 3 on one of its two faces.

The tongue 1 is glued to the location of the rib 2 with non-brittle glue 4 on the cover 5 of a container 6.

The rib 2 separates the tongue 1 into two arms: one 7 said to maneuver, and the other 8 said to be drilling.

By lifting upwards (arrow 9, FIG. 3), the operating arm 7 of the tongue 1, the latter swivels around the rib 2 so that the end of the drilling arm comes to touch the cover 5 (FIG. 3, dotted position). This tilting is possible because of the flexibility of the cover 5 which deforms slightly, and, if necessary, because of the flexibility of the glue 4.

The lifting of the operating arm continuing, the end of the piercing arm 8 starts and pierces the cover 5. In order to facilitate this operation, the end of the piercing arm 8 is angular (tip 10).

By continuing the pivoting of the tongue 1 around the rib 2 until it is placed in a position substantially perpendicular to the plane of the cover 5, the piercing arm widens the tear in the cover until the width 1 of tongue 1 is substantially obtained. level of the rib 2. The piercing arm 8 gradually widens from the tip 10 towards the rib 2 so as to facilitate the gradual widening of the tear.

Once the cover is pierced and torn over the width 1, it suffices, if one wishes to extend the opening, to pull the tab 1 by the operating arm 7 in the direction opposite to the drilling arm, so as to continue the tear.

The tear continues generally on the width 1. This operation is particularly easy if, in the case of a composite cover comprising a plastic material, the tear takes place in the direction in which the plastic has been extruded : it is therefore preferable in this case to place the tongue with its rib 2 perpendicular to the orientation of the plastic film.

Naturally, if the cover has weakening lines, made for example by pre-impression, the tongue can be placed so that, during the pivoting of the latter causing the piercing and the beginning of tearing of the cover, the tear meets the lines of embrittlement and, by continuing to pull the tab, the tearing continues along the lines of embrittlement. These can be provided so as to obtain an annular tear which goes all around the cover and making it possible to remove the latter almost entirely.

The rib 2 of the tongue 1 can be constituted by an insert fixed to the tongue; it can be formed by the bead of adhesive 4 itself if it is large enough.

Preferably, the rib 2 is formed integrally with the tongue 1 and can be, in the case where the tongue is made of plastic material, a simple deformation (FIG. 3) obtained hot or cold by stamping.

The height of the rib 2 is not critical, and can be chosen to be 1 to 2 mm for example.

From it, and from the length of the drilling arm, depends the angle at which the point 10 of the drilling arm 8 attacks the cover 5, an angle in relation to the ease of drilling.

In order to be able to drill the cover 5 manually without difficulty, it is preferable that the length of the lever arm a of the drilling arm is less than that b of the gripping arm (FIG. 2), for example in a ratio of one quarter or a third.

In order to facilitate manual gripping of the gripping arm 7, the latter is provided with a spacer stud 11 on its face 3. This stud can be obtained like the rib 2 by stamping.

The stud 11 can be very slightly glued to the cover 5, so as to oppose a fortuitous lifting of the operating arm 7 resulting in accidental drilling. The bonding is however weak enough to yield under the effort of the operator during the intentional manual lifting of the tongue 1. Although the tongue 1 can be placed, which is of any size depending on the type of opening that is desired practice, at many locations on the cover, it is advantageous to place it, as shown in Figures 1 to 3, so that the end 10 of the drilling area 8 is located in the immediate vicinity of the edge 12 from the edge of the container 6 on which the cover 5 is placed. In this way, when the tongue 1 has pivoted and the point 10 begins to attack the cover 5, the point of attack 13 of the bore is very close (for example from 1 to 3 mm) of the edge 12 of the edge of the container, so that this region of the lid is supported by the presence close to the edge, and slightly deformed and the drilling is thus facilitated (shearing effect).

The invention applies to any kind of tear-off cover under the action of a rigid wedge piece, the tear of which can be possibly extended by pulling the torn part.

In particular, the invention applies to the opening of thermoformed containers with a heat-sealed non-peelable lid. This is particularly the case for thermoformed containers from a polystyrene 14 / polyethylene 15 composite strip provided with an aluminum 16 / polyethylene 17 composite cover sealed by autogenous welding on the edges of the container.

In the context of such containers, it is particularly advantageous, when the shape chosen for the tongues 1 is suitable, to form them in the thermoplastic strip 18 (FIGS. 4, 5) for forming the containers in the star waste. (Figures 4, 5) remaining between the containers.

We will explain (Figures 4.7) in what follows an example of manufacture and implementation of the opening tabs 1 in the context of conventional equipment for packaging thermoformed containers comprising downstream of a whole chain of thermoforming stations, filling, sealing of a cover strip, a station 19 for cutting containers.

The containers are cut in a known manner by means of dies and punches not shown, over the entire width of the strip 18 and in steps of two containers for example. These techniques are known to those skilled in the art and will not be further described.

The tongues 1 are advantageously formed in the stars situated between the containers, at the level of the cutting station 19 for the containers. At this level, the strip 18 carries the thermoformed containers 6 and is covered with the cover strip (for example made of aluminum / polyethylene composite): consequently, by being cut at this station 19, the tongues 1 will be formed from a structure comprising, on the one hand, this thermoplastic composite and, on the other hand, the cover strip, which will allow, by an adequate impression of the cover strip, to make appear on the tongue 1 the desired indications (such as arrows or codified opening instructions) or any patterns.

In order to cut the tongues 1 simultaneously with the cutting of the containers 6, the lower cutting tool 20 used for cutting the containers 6 is provided with embossed punches 21 in the shape of the tongues 1 and located in the interior areas. - containers. The punches 21 cooperate with dies 22, the inlet section of which coincides with the section of the punches 21 so as to allow the tongues 1 to be cut by shearing. These have been previously stamped in the container forming station to form their surface the rib 2 and the stud 11, so that these are perfectly formed tongues which pile up as they are cut in the dies 22 (this stacking of tongues 1 has only been shown on the right matrix of Figure 6).

In order to limit the friction of the tongues on the walls of the dies, which could lead to a blockage, the walls of the matrix are, in general, wider than at their entry section.

The tongues 1 are led to the exit of the dies 22 by guides 23 which can in particular be guides produced from several filiform guides enclosing the tongues, which can be specially shaped for this purpose by having concave edges, or even notches, allowing easy guidance by this type of guide.

At the outlet of the guides 23, each tongue is taken up by an elastic clamp 24 mounted on a rotary drum 25 around an axis 26 perpendicular to the direction of advance 27 of the strip 18.

The elastic clamps 24 can be produced as shown in FIG. 7 by a plate 28 carried by a foot 29 capable of sliding to more or less enter the drum 25. The plate 28 is provided with elastic retaining elements 30 which allow a tongue 1 to snap in and wear against the plate 28.

During a rotation of the drum 25, the tongues 1 passing in front of a gluing station 31 where the ribs 2 (and the spacer pins 11, if any) are glued.

After having again rotated a suitable angle, the pliers 24 come to deposit the tongues 1 on the lids of the pots 6a, 6b situated above the recovery belt 32, by means of an expulsion rod 33 slidably mounted in each clamp 24.

It should be noted that, as can be seen in FIGS. 4 and 5, the tongues are taken from the regions between the containers and deposited on the containers at a location generally offset transversely to the location of the removal. It is therefore necessary to take account of this lateral offset, either at the level of the guides 23, or by a device associated with the clamps 24 allowing them to carry out during the rotation of the drum 25 a small lateral transfer.

In order to ensure exact placement of the tongue, on the containers 6a, 6b, it is good that the position of these is itself very precise.

To this end, it is planned, at the cutting station 19, not to completely detach the containers 6c (FIG. 4) in the cutting station 19 from the containers 6e immediately upstream, and to maintain them by a part not cut on their common side 34; thus, after advancing one step during which the containers 6c, 6d have taken the position 6a, 6b in which they receive the tongues, the containers 6a, 6b are perfectly positioned since they are still connected to the containers upstream.

They will be separated from it by the cutting tools of the station 19 which include means for cutting the last remaining fastener (that is to say the common side 35 corresponding to the side 34 advanced by one step). The containers are then free to be taken up by the belt 32 for storage or the like.

Figures 8 to 12 show a second embodiment of the piercing device 101 fixed to the cover 102 of a container 103 whose upper edge 104 is made integral, for example by sealing, the edge of the cover 102. The piercing device 101 is applied to lids which are tearable and which, preferably, cannot be separated easily from the container, for example by peeling.

The piercing device 101 comprises a rigid upper tongue 105 and a flexible lower tongue 106 which are superimposed and have substantially the same contours, seen in plan (see FIG. 10). In its front part, the flexible tongue 106 is firmly fixed to the corresponding part of the rigid tongue 105 which must form the drilling arm. The area for fixing the flexible tongue 106 to the rigid tongue 105 is generally smaller than the free area for the rigid tongue 105. The other face of the flexible tongue 106, that is to say the underside, diverted from the rigid tongue 105 is fixed, preferably over its entire surface and, in any case, along a surface larger than the area for fixing the flexible tongue 106 on the rigid tongue 105, on the cover 102 in particular so that the fixing zone between the flexible tongue 106 and the rigid tongue 105 faces the edge of the opening of the container 103.

Thanks to this kind of attachment between the rigid 105 and flexible 106 tabs and the flexible tab 106 on the cover 102, a drilling arm 107 and an operating arm 108 are produced on the rigid tongue 105 which preferably is larger than the drilling arm 107.

There is thus produced at the inner rectilinear limit of the zone for fixing the rigid 105 and flexible tabs 106 one on the other and being located below the zone for fixing the flexible tab 106 on the cover 102, an axis d hinge 109 which is itself firmly fixed both to the rigid tongue 105 and to the flexible tongue 106 and thereby to the cover 102 and which allows the pivoting of the operating arm 108 upwards (see arrow F1, FIG. 9 ) and of the drilling arm 107 downwards so that the latter tears the cover 102. Then by pulling the operating arm 108 backwards in the more or less horizontal direction indicated by the arrow F2, the following cover can be torn the contours determined by those of the flexible tongue 106.

The material of the container or the rigid tongue is immaterial provided that the latter can be fixed properly on the flexible tongue. It is the same with regard to the materials of the cover and the flexible tongue provided that the cover can be torn by the rigid tongue and that the flexible tongue can be fixed firmly on the rigid tongue and on the cover and that this fixation withstands the forces applied to the various connections.

When using the piercing device 101 with thermoformed containers and covered with covers of aluminum foil or strip or of a sheet or complex strip comprising a metallic film, it is advantageous to manufacture the rigid tongue 105 from the thermoplastic container strip and the flexible tabs 106 from the aluminum strip.

In Figure 10 is shown a plan view of a portion of cover strip 110 covering the container strip. The opening 111 of the containers is shown in broken lines, the cutting lines 112 of the edges of the containers with their sealed lids being shown in solid lines. Several grouped receptacles can be separated from each other along the lines of weakness 113.

The cover strip 110 is sealed on the edges of the containers in the annular zones 114 between the lines 112,113 on the one hand and the openings 111 on the other hand.

It can be seen in FIG. 10 that the cutting lines 112 between four containers delimit an intermediate star-shaped zone 115 which, in principle, constitutes waste. According to a feature of the invention, this intermediate zone 115 is used for the manufacture of the assembly - rigid tongue 105 flexible tongue 106 -. To this end, the front part of flexible tab 106 (part of aluminum strip provided with a heat-bonding film located in the intermediate zone 115) is sealed (under pressure and hot) on the corresponding part of the container strip. and subsequently constituting the rigid tongue 105, this sealing preferably being carried out at the same time as the sealing of the covers on the edges of containers in the annular zones 114. The sealing zone 116 of the flexible tongue 106 has been indicated on the rigid tongue 105 by hatching and the internal limit of this zone 116 by a straight line 117 extending perpendicular to the longitudinal axis of the rigid tongue 105.

After this partial sealing of the flexible tongue 106 on the rigid tongue 105, the rigid tongue assembly 105 is cut flexible tongue 106 - along the contours 118 and then preferably glued the entire free face of the flexible tongue 106 before to apply it, in the inverted state, against the cover, so that the pointed part (piercing arm 107) of the rigid tongue is located near the opening 111 of the container. In other words, the outside face of the cover and the outside face of the flexible tongue 106 are glued back to back one on the other, these faces having been in the same plane and on the same side in the strip of covers 110 before the cutting of the rigid 105 and flexible 106 tabs (see reference 119 in FIG. 10).

The installation for manufacturing the piercing device 101 comprises the means mentioned above which are obviously adapted to the shape of the tongues and to the places of their application.

It is self-evident that the sealing zone 116 corresponds to the zone of the rigid tongue 105, zone forming the piercing arm 107 and the straight 117 will later constitute the right articulation 109 when the piercing device is fixed on the cover 102 of container 103.

FIGS. 11 and 12 show an installation for manufacturing a piercing device according to the invention, this installation being associated with or preferably incorporated in packaging equipment 120 of the type which thermoforms containers 103 from a thermoplastic strip 121 which fills them with a product, which seals the filled containers using a flexible strip with lids 110 and which, finally, cuts the filled and sealed containers 103 from the thermoplastic strip 121 and the strip to covers 110. The packaging equipment 120 is of a known structure so that it is not necessary to describe it in detail. This equipment 120 successively comprises a heating station not shown of the thermoplastic strip 121, a thermoforming station not shown in which are made cells constituting the containers 103 which still remain attached to said strip 121, a filling station in which the containers 103 are filled with a product, a sealing station 122 in which the cover strip 110 previously placed on the thermoplastic strip 121 so as to cover the openings 111 of the containers 103 and the edges surrounding them, is heat sealed and under pressure, along annular sealing zones 114 on said edges, and a cutting station 123 in which the sealed containers 103 are cut, either individually or in groups, from the thermoplastic strip 121 and the cover strip 110 outside sealing zones 114 along cutting lines 112 before being evacuated, for example using a conveyor belt 124 to an overpacking station not shown.

In the present case, the thermoplastic strip 121 is advantageously used for the containers and the cover strip 110 to produce the two-arm lever comprising the rigid tongue 105 and the flexible tongue 106 when there are sufficiently free intermediate zones 115 large between the sealing zones 114 of several neighboring containers and belonging to two successive rows of containers. Of course, it is also possible to produce the lever assembly constituted by a rigid tongue 105 and a flexible tongue 106 by using two superimposed tapes, one of which is made of rigid thermoplastic material and the other of which is made of a flexible material, foldable and heat-sealable, that is to say capable of being heat sealed and pressurized on the strip of rigid thermoplastic material.

As can be seen in FIGS. 11 and 12, the installation for manufacturing the drilling device comprises sealing means 125 comprising a heated upper punch 126 and a lower counter-punch 127, the working faces of which have a configuration identical to that of the sealing zones 116 of the tongues 105 and 106 (see also FIG. 10). In the case of the embodiment shown in FIGS. 10 to 12, the punches 126 and the counter punches 127 are provided in the sealing station 122 and carried respectively by the punches 128 and counter punches 129 used to seal the strip of cover 110 on the thermoplastic container strip 121 along the annular zones 114.

The rigid tongue 105 - flexible tongue 106 assemblies are then cut either from the above-mentioned pair of ribbons, or from the set of superimposed bands consisting of the container strip 121 and the cover strip 110, this cutting being carried out according to the predetermined shape 118 of the pairs of overlapping tabs 105, 106 and such that the sealing area 116 of each pair of tabs 105, 106 is located to the right of the drilling arm 107 and is separated from the unsealed area by the separation line 117 which will later materialize the hinge pin 109 of the drilling device. The cutting of the superimposed tongues which are heat-sealed one on the other 105, 106 is carried out using cutting means 130 of the type comprising a cutting punch 131 and a fixed bottomless die 132 arranged on either side. 'other of the pair of ribbons or superimposed strips 110, 121. The pairs of cut tabs 105, 106 are discharged through the bottom of the dies 132 either in transfer means 133 constituted either by removable storage cartridges or by guide rails. When the pairs of tabs 105, 106 are cut from a pair of superimposed ribbons, their storage is carried out in cartridges connected to the open bottom of the dies 132 and preferably provided with a return spring which subsequently facilitates expulsion. one by one of the pairs of tongues 105, 106 above a determined location of a flat cover 102 sealed on the edge of the corresponding container 103, said determined location having been previously coated with a tiny layer of glue or a glue drop 134 from an appropriate glue dispenser 135.

In the case of the exemplary embodiment shown in FIGS. 11 and 12, the matrix 132 is arranged above the pair of bands 110, 121 and the corresponding punch 131 is disposed below said pair of bands at the predetermined locations 136 for the cutting of the pairs of tongues 105, 106. The cutting means 130 can be provided either in the cutting station 123 of the sealed containers or one or more steps of tape advance upstream of said station 123, the step of advancing strip being equal to the width of a cut container, width taken in the direction of advance F, of the pair of strips 110, 121. Of course, the punches 131 are controlled synchronously with the cutting elements of the station 123 .

In the present case, the guide rails 133 can be produced by tubes having a cross section adapted to the configuration of the pairs of tongues 105, 106 and shaped so as to have a semi-circular central part 136 and two vertical lateral parts 137, 138 one of which (137) opens at its lower end above the bottom of the matrix 132 and the other (138) of which is closed at its lower end by a window pusher 139 of a known type (for example of the kind of pushers used in slide projection apparatus) and is arranged near the place of depositing a pair of tabs 105, 106 on the area of the previously glued lid. The window pusher 139 is in a horizontal position and spaced from the cover strip 110 by a distance at least slightly greater than the thickness of a pair of tabs 105, 106 which, during its transfer into the slide 133 a been turned 180 °. When the window part of the pusher 139 is laterally extended from the slide 133, the latter is located below an applicator piston 140 which after having pushed a pair of tabs 105, 106 out of the window where it was retained on its edges by elastic means, press it against the previously glued area of the cover strip 110, area situated directly above the opening of a container 103. It will be noted in FIGS. 10 and 11 that the means of sealing 125, the gluing means 135 and the means 140 for applying the pairs of tongues 105, 106 are arranged one behind the other (with the appropriate lateral offset) in the direction of advance of the strips 110, 121 and that the cutting means 130 are arranged downstream of the application means 140. When the transfer slide 133 is completely filled with a pair of tongues 105, 106, each punch cutting movement 131 will automatically introduce a pair of tongues 105, 106 into the pusher window 139 at the other end of the slide 133. It should also be noted that the type of slide 133 cooperates at one end with the open bottom of a cutting die and at the other end with a window pusher 139 can also be used when the cutting means 130 do not cooperate with a pair of bands 110, 121, but with a pair of ribbons independent of said pair of bands. This could in particular be the case when the free zones 115 between the edges of containers 103 are too small to allow the pairs of tongues 105, 106 to be cut at these locations.

Claims (16)

1. Method for providing container lids with piercing tabs, said tabs piercing said lids by leverage effect, said lids being produced in a tearable material, which method consists in producing substantially plane rigid tabs (1; 105) which are fixed on the lids (5; 102), so as to divide them into a piercing arm (8; 107) and a handling arm (7; 108), characterized in that the tabs (1; 105) are cut from a rigid thermoplastic strip (18; 121) for use in the manufacture of thermo-shaped containers (6; 103) which, after being filled with a product, are closed by a supple and tearable lid (5; 102) produced from a lid strip (110) superimposed on said thermoplastic strip (18; 121) comprising the containers, in materializing on said tabs (1; 105) an axis of articulation (2; 109), transferring the cut tabs (1; 105) towards the corresponding lids (2; 109), and in subsequently fixing each tab (1; 105) by its pivoting axis (2; 109) to one of the corresponding lids (5; 102) when said lids are in a closing position on the containers (6; 103).

2. Method according to claim 1, characterized in that the rigid tabs (1; 105) are fixed to the lids (5; 102) when the containers (6; 103) are still secured to the rigid thermoplastic strip (18; 121).

3. Method according to any one of claims 1 and 2, in which the thermoplastic strip (18; 121) comprises container-shaping areas, and free areas (115) between said shaping areas, characterized in that the tabs (1; 105) are cut from said free areas (115) and in that the cut tabs (1; 105) are transferred towards the corresponding lids (5; 102) so as to shift them transversely with respect to their gripping station.

4. Method according to any one of claims 1 to 3, characterized in that an axis of articulation (2) is materialized by forming a rib (2) on the tab (1) and fixing the tabs (1) via their rib (2) on the lids (5).

5. Method according to any one of claims 1 to 4, characterized in that the tabs (1) are covered with an adhesive material during their transfer between their cutting station (21, 22) and the lids to which they are secured.

6. Method according to claims 1 to 3, characterized in that said pivoting axis (109) of said rigid tab (105) is materialized by providing said tabs contiguously with a supple tab (106) having at least about the same extension as said rigid tabs (105) which supple tab is secured by one face to said rigid tabs (105) solely on the side of said piercing arm (107) and by the other face to said lids (102) at least on the side of said handling arm (108) of said rigid tabs (105).

7. Method according to claim 6, characterized in that the rigid tabs (105) are produced in the rigid thermoplastic material of the thermoplastic strip (18; 121) comprising the containers (6; 103) and the supple tabs (106) in a supple and thermo- sealing composite material, constituted by the lid strip (110), in that the lid strip (110) is thermo-bonded on the thermoplastic strip (121) inside the free areas (115) between the containers (103) in areas (116) designed to form subsequently said piercing arm (107) of the rigid tabs (105), in that assemblies of rigid (105) and supple (106) tabs comprising particularly said areas (116) are cut from superimposed strips (121, 110), in turning said assemblies (106, 107) by 180° during their transfer from the cutting station (130) to the station for fixing them on the lids (102), and owing to an adhesive substance, said assemblies are bonded by the supple tab (106) on the lids (102).

8. Method according to any one of claims 6 and 7, characterized in that at each step forward, said lid strip (110) is thermo-bonded on said thermoplastic strip (121) at a first station, the bonding being effected on the rims (114) of said containers and in areas (116) designed to form subsequently said piercing arm (107), a small quantity of adhesive (134) is deposited, at a second station, on said lids of said containers (103), assemblies of one rigid tab (105) and one supple tab (106) are deposited on said lids (102) at a third station, and such assemblies of rigid (105) and supple (106) tabs are cut at a fourth station, with a view to transferring them towards the third station, and finally said containers are cut at a fifth station (123).

9. Device for piercing the lid of containers by leverage, of the type comprising substantially plane rigid tab (1), said lid (5) being produced in supple and tearable material, and the rigid tab (1) being provided with a pivoting axis (2) which divides the tab into a piercing arm (8) and a handling arm (7) and which is secured to the lid (5), characterized in that the pivoting axis (2) is constituted by a rib (2) of the tab (1).

10. Device for piercing the lid of containers, by leverage, of the type comprising a substantially plane, rigid tab (101), said lid (102) being produced in supple and tearable material, the tab being provided with a pivoting axis (109) which divides the tab into a piercing arm (107) and a handling arm (108) and which is secured to the lid (102), characterized in that it comprises a second supple tab (106) having at least about the same extension as the rigid tab (105) and fixed, on one side, on the piercing arm (107) of the rigid tab (105) and on the other side, at least in the area covered by the handling arm (108) of the rigid tab (105) on the lid (102).

11. Installation for producing a device for piercing the lids of containers by leverage, said lid being produced in supple and tearable material, characterized in that it is associated to a packaging installation (120) of the type which consists in thermo-shaping the containers (103) from a thermoplastic strip (121), filling the container with a product and sealing them with a lid strip and finally cutting the sealed containers (103) from the thermoplastic strip (121) and from the lid strip (110), and in that means (20, 21, 22; 130, 131, 132) are provided to cut substantially plane tabs (1; 105) from the thermoplastic strip (121), means (126, 127) for providing the tabs (1; 105) with a pivoting axis (2; 109) dividing the tabs (1; 105) into a piercing arm (8; 107) and into a handling arm (7; 108), means (23, 24, 25, 28, 29; 133, 136,137,138,139) for transferring said cut tabs (1; 105, 106) from the cutting station to the station where the tabs are fixed to the corresponding lids (5; 102) and means for fixing said pivoting axis (2; 109) to the lids (5; 102) of the containers (6; 103).

12. Installation according to claim 11, characterized in that said means for providing the tabs with a pivoting axis consist in means for forming ribs (2), provided at the container-shaping station (6) upstream of the means (20, 21, 22) for cutting the tabs (1).

13. Installation according to any one of claims 11 and 12, characterized in that the means for cutting (20, 21, 22; 130, 131, 132) the tabs (1; 105) comprise a bottomless die (22; 132) issuing into a guiding means (23; 137) guiding transfer means (23, 24, 25, 28; 133).

14. Installation according to any one of claims 11 to 13, characterized in that it is provided with an adhesive-coating station (31) on the path of the transfer means (23, 24, 25, 28, 29) which further comprise gripping means (30) and means for applying (33) the tabs (1) on the lids (5).

15. Installation according to claim 11, characterized in that it comprises as means for providing the tabs (105) with a pivoting axis (109), means for sealing (125) the supple lid strip (110) on the rigid strip (121) in free areas (115) between the containers (103), in areas (116) corresponding subsequently to said piercing arms of the different rigid tabs (105), means for cutting (130, 131, 132) assemblies of superimposed rigid and supple tabs (105, 106), means for transferring (133) the cut and sealed assemblies of rigid and supple tabs (105, 106) from the cutting station (130) to the station where said assemblies are placed on said lids of said sealed containers (103), means for adhesively coating (135) either the free face of the supple tab (106) on the area of the lid which is meant to receive the assembly (105, 106) of rigid and supple tabs, as well as means for applying (139, 140) said assemblies of rigid and supple tabs (105, 106) on the corresponding lids so that the free face of the supple tab (106) is firmly bonded to said lid (102) at least in the area covered by the handling arm (108) of the rigid tab (105).

16. Installation according to claim 15, characterized in that the sealing means (125) comprise a heated upper punch (126) and a lower counter punch (127) both of which have working faces of identical configuration to that of the sealing areas (116) of the rigid tabs (105) on the supple tabs (106), and in that the punch (126) and the counter-punch (127) are provided in the station for sealing the containers (122) and carried respectively by the punch (128) and the counter-punch (129) used for sealing the lid strip (110) over the (121) thermoplastic container strip along annular areas (114).

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