FR2782699A1 - SCREW CAP HAVING A SECURITY BELT WITH TURNED TONGS, MOLD AND METHOD FOR MAKING THIS CAP - Google Patents

Abstract

The invention concerns a screw top (2) comprising a skirt (6) closed by a base (4) and a tamperproof ring (12) linked to the skirt by frangible bridges (10), the tamperproof ring (12) comprising a lip (14) folded inwards and towards the top base. It further comprises axial stops (18) arranged between the tamperproof ring (12) and the skirt (6), as well as an undercut provided at the tamperproof ring base, on the side opposite to the top base (4). Said top can be produced in a single moulding/stripping operation in a mould comprising a fixed base opposite a mobile part or mould base, a stripper portion or stripper ring, a core designed to be lifted by a translation movement, without rotation, and mould slides placed between the mould base and the stripper portion.

Description

The present invention relates to a screw cap having a belt

  tamper evident with tabs turned over, a mold for making this stopper and a process used to make this stopper. The documents FR 2 525 565 and FR 2 744 052 describe plugs of this type. We then have a screw cap with a bottom and a threaded skirt. The latter is provided, on its free edge opposite the bottom of the stopper, with a tamper-evident ring which has tongues turned towards the bottom of the stopper and cooperating with an annular rib produced on a bottle intended to receive the stopper. The

  tamper-evident ring is connected to the skirt by breakable bridges.

  As can be seen in patent FR 2 744 052, such a stopper can be produced by turning the tabs of the tamper-evident ring in the mold. The method then used provides that the core of the mold is withdrawn in the axial direction of the stopper without rotation, then, after its extraction, the core is pushed back towards the stopper thus causing the tongues to fold back towards the inside of the tamper-evident ring and ejection

plug out of the mold.

  To make this stopper using this method, you must be able to hold the stopper during the tab folding operation. To this end, an undercut that can be seen in the figures of document FR 2 744 052 is provided on the periphery of the tamper-evident ring so that the thickness of this ring is less on the side of the cap skirt. These caps have the following drawback: when screwing the cap on a container neck, it happens that the tamper-evident ring passes inside the skirt of the cap. A pinch is then carried out. To avoid pinching the tamper-evident ring, it is known to place axial stops between the skirt of the cap and the tamper-evident ring. To be able to place these stops, we need a thickness of tamper-evident ring facing the skirt of the stopper sufficient to be able to put a stop there. This is not the case when the tamper-evident ring is provided with an undercut as indicated above and shown in

document FR 2 744 052.

  The plugs comprising such axial stops have a tamper-evident ring of substantially constant width. It is therefore not possible to hold the cap to turn the tabs in the mold. The tongues are then turned over in a subsequent operation,

for example by rolling.

  The disadvantage of this latter technique is that the plugs are removed from the mold during a first operation and then the tongues, or else a continuous lip, are turned over by rolling.

during a subsequent operation.

  The object of the present invention is therefore to provide a stopper which can be produced by a process allowing a tamper-evident ring to be produced in a single operation, comprising both tongues.

turned and axial stops.

  To this end, the stopper which it offers is of course of the type comprising a cylindrical skirt provided with at least one screw thread and closed at one end by a bottom as well as a tamper-evident ring connected to a free end of the skirt by breakable bridges, the tamper-evident ring comprising tabs which, turned inward and towards the bottom of the cap, are intended to cooperate with a rib

  ring located on the neck of a container intended to receive the stopper.

  According to the invention, there are also axial stops on this plug disposed between the tamper-evident ring and the edge of the skirt to which the tamper-evident ring is attached, as well as an undercut produced at

  bottom of the tamper-evident ring, on the side opposite the bottom of the cap.

  A process then allowing this plug to be produced in one

  only operation is described below.

  In one embodiment of the stopper according to the invention, the undercut produced on the tamper-evident ring is in the form of a peripheral projection whose height decreases towards the skirt of the stopper. The invention also provides a mold for producing a plug comprising a cylindrical skirt provided with at least one screw thread and closed at one end by a bottom as well as a tamper-evident ring connected to a free end of the skirt by breakable bridges, the tamper-evident ring comprising tabs which, turned inwards and towards the bottom of the stopper, are intended to cooperate with an annular rib situated on the neck of a container intended to receive the stopper, having a base fixed opposite to a movable part or bottom of the mold, the inner wall of which corresponds to the outer surface of the skirt and of the bottom, a stripping part or loosening ring, the inner surface of which corresponds substantially to the outer surface of the tamper-evident ring and a core intended to be removed by a translational movement, without rotation, and whose outer surface corresponds to the

  inner surface of the bottom, the skirt and the tamper-evident ring.

  According to the invention, this mold also has drawers placed between the bottom of the mold and the deviator part and which can move

substantially radially.

  A method for making a plug as described above in a single operation is for example the following method. This process for producing a plug comprising a cylindrical skirt provided with at least one screw thread and closed at one end by a bottom as well as a tamper-evident ring connected to a free end of the skirt by breakable bridges, the ring tamper evident comprising tabs which, turned inwards and towards the bottom of the cap, are intended to cooperate with an annular rib situated on the neck of a container intended to receive the cap, comprises the following steps: a- injection of synthetic material in a closed mold having a fixed base opposite to a movable part or bottom of the mold, the inner wall of which corresponds to the external surface of the skirt and of the bottom, a stripping part or loosening ring, the internal surface of which corresponds substantially to the outer surface of the tamper-evident ring and a core whose outer surface corresponds to the inner surface of the bottom, of the skirt and of the tamper-evident ring, as well as drawers placed between the mold base and the deviating part, b- withdrawal of the mold base in an axial direction, c- withdrawal of the drawers in a substantially radial direction relative to the axis of the plug, displacement of the core and the deviating ring to release the plug from the fixed base, e- relative movement of axial translation, without rotation, between the deviating part and the core, the plug being retained by the deviating part, f- movement relative in opposite direction of the core and of the deviating part so as to produce the reversal of the tabs of the ring

  tamper evident and ejecting the plug from the mold.

  During the relative movement between the deviating part and the core, that is to say when the core is withdrawn from the plug, the latter is held by the deviating ring thanks to the undercut produced on the

tamper-evident ring.

  In any case, the invention will be well understood using the

  description which follows, with reference to the appended schematic drawing,

  representing by way of nonlimiting examples an embodiment of a

  plug and a mold according to the invention.

  Figure 1 is a perspective view of a plug according to the invention, Figure 2 is an enlarged view, in longitudinal section of the plug of the previous figure, Figures 3 to 11 are views in longitudinal section of a mold according the invention during various stages of manufacturing a stopper according to the invention, and Figure 12 is a detail view on an enlarged scale showing the

holding the plug in the mold.

  Figures 1 and 2 show a plug according to the invention.

  This plug 2 comprises, in a manner known per se, a bottom 4 extended by a skirt 6 having an internal thread, formed of threads 8. The skirt 6 is connected, at its free end, by a plurality of bridges 10, regularly distributed over its periphery, to a tamper-evident ring 12. These bridges are breakable under the effect of a certain constraint. This plug 2 is intended to equip a container whose neck has a thread having external ribs corresponding to the threads 8, as well as a rib

  ring arranged below the external thread.

  The tamper-evident ring 12 has several tabs 14 regularly distributed. The connection between the ring and each tongue is produced by a thinned zone of material 16 forming a film hinge, allowing the tongue to be folded inwards. In Figures 1 and 2, the tabs 10 are shown in their final position, as they are on the neck of the container. They are folded towards the bottom 4 of the plug and are substantially parallel to the wall of the ring.

  tamper evident 12 and the skirt 6.

  These tongues 14 are intended to cooperate with the annular rib of the neck of the container during the first unscrewing of the cap 2. During this first unscrewing, the tongues abut against the annular rib before the complete unscrewing, thus preventing the tamper-evident ring from go beyond this rib. By continuing to exert a torque of unscrewing on the skirt 6, the breakable bridges 10 give way. The ring 12 then remains below the annular rib and the skirt 6 can

  be unscrewed, allowing access to the contents of the container.

  The tamper-evident ring of the cap according to the invention has axial stops 18 placed between the tamper-evident ring and the skirt of the cap. These axial stops 18 are made on the tamper-evident ring 12. Of course, they could be made on the free edge of the skirt 6 connected to the ring 12. These stops 18 allow during the first screwing of the plug 2 with the ring 12 on a container neck to prevent the ring

  tamper evident 12 to pass inside the skirt 6 of the cap.

  The tamper-evident ring 12 according to the invention has on its outer face, at the end opposite to the skirt 6 of the plug when the tongues 14 are turned over, a projection 20 making it possible to produce an undercut. This projection 20 is peripheral and its height decreases towards the skirt 6 of the plug. The tamper-evident ring 12 therefore has over its entire height, apart from the tongues 14, a thickness that is substantially

  constant as seen in Figure 2.

  The projection 20 and the undercut thus produced on the tamper-evident ring make it possible to maintain the stopper during the operation of turning the tongues during the manufacture of the stopper. This

  is explained in more detail below.

  Figures 3 to 11 show in section a mold for making a plug such as that described above. This mold comprises inter alia: a first movable part designated by the bottom of the mold 22, a second part called stripping part or deviating ring 24, a fixed base 26 on which slides the deviating ring 24, a fourth part constituting the core 28 of the mold, as well as drawers 30 arranged between

  the feeder ring 24 and the mold base 22.

  The inner surface of the bottom of the mold 22 corresponds to the outer surface of the skirt 6 and of the bottom 4. The inner surface of the deviator ring 24 corresponds to the outer surface of the tamper-evident ring 12. Finally, the part of the base fixed coming into contact with the plug corresponds to the face of the tabs 14 located inside the

  cap once the tabs 14 are turned over.

  The core 28 gives its shape to the inner surface of the plug, that is to say the bottom 4, the skirt 6 and the tamper-evident ring 12. It is made up of an internal element 28a and an envelope outer 28b movable in axial translation relative to each other. This two-part embodiment of the core 28 makes it possible to produce a sealing chimney 32 attached to the bottom 4 of the plug. A space corresponding to this sealing chimney is created between the element

  28a and the outer casing 28b on the side of the mold base 22.

  The drawers 30 make it possible to form the axial stops 18 and the

jumpers 10.

  Figures 3 to 11 illustrate a method of producing a plug according to the invention, showing in particular the various stages of demolding. In Figure 3, the mold is in the closed position. The different constituent parts of the mold come against each other in a compact position. A free space remains, however. Of the material

  synthetic is injected into the mold and the plug 2 is formed.

  In Figure 4, the bottom 22 of the mold has been removed by a translational movement. Most of the outside of the

cap is then removed from the mold.

  In FIG. 5, with respect to the position shown in FIG. 4, only the drawers 30 have been moved in a radial direction, in

moving away from the plug.

  Then, the deviating ring 24 is moved in the direction of the arrow 34 in FIG. 6, that is to say away from the fixed base 26. The core 28 follows the movement of the deviating ring 24. The tongues 14

are thus released on one side.

  In order to then be able to remove the core 28 by a relative translational movement without rotation relative to the deviating ring 24, the internal element 28a is first of all offset with respect to the casing 28b in the direction of the arrow 34 in order to be able to release the sealing chimney 32. The deviating ring 24 follows the internal element 28a in

  its movement to find itself in the position shown in Figure 7.

  The core 28 is removed from the inside of the plug, according to a method known per se, by a translational movement of the deviator ring 24 according to arrow 34, without unscrewing. During this step, the skirt 6 deforms. It is to allow free deformation of the skirt 6 that the mold base 22 is removed before the core is removed. The tongues 14 of the tamper-evident ring 12 are driven by the core 28 and are found in a substantially radial position, as shown in FIGS. 8 and 9. The plug 2 is maintained during this removal operation of the core 28 thanks to the undercut formed at

projection level 20.

  To fold the tabs 14 and put them in a position where they are substantially parallel to the skirt 6 and to the tamper-evident ring 12, the two elements 28a and 28b of the core first return to their initial position by a translational movement in the direction of arrow 36, that is to say approaching the fixed base 26 (Figure 9). The deviator ring 24 is provided with a translational movement in the direction of the arrow 36 (FIG. 10), so that the tongues 14 approach the core 28. FIG. 10 illustrates the moment when the tongues 14 come into contact of the core 28 and o the core 28 folds the tabs 14. The translational movement of the deviator ring 24 in the direction of the

  arrow 36 is continued until the plug is ejected from the mold.

  This produces in a single operation on a plug the folding of the tabs of the tamper-evident ring and the axial stops avoiding the pinching of this plug during its screwing on a neck of

container.

  Maintaining the stopper during this operation is ensured by the projection 20 and the corresponding complementary shape of the deviator ring 24. FIG. 12 shows in detail this projection 20 and the corresponding part of the mold. It is thus clearly seen how the stopper is driven by the deviator ring 24 during the movements of the latter and also how the stopper is held during folding.

tabs 14.

  The method described above avoids using a stopper produced according to a method of the prior art either to make a cut between the tamper-evident ring and the skirt of the stopper to make the axial stops, or to fold the tabs, by cold rolling

for example.

  The method according to the invention allows significant time and material savings which is appreciable on the cost price of the plug produced. It goes without saying that the invention is not limited to the embodiments of a stopper and a mold, nor to the process described above; on the contrary, it embraces all variants within the framework of

claims below.

Claims (4)

  1. Cap (2) comprising a cylindrical skirt (6) provided with at least one screwing thread (8) and closed at one end by a bottom (4) as well as a tamper-evident ring (12) connected to a free end of the skirt by breakable bridges (10), the tamper-evident ring (12) comprising tabs (14) which, turned inwards and towards the bottom of the cap, are intended to cooperate with an annular rib situated on the neck of a container intended to receive the stopper, characterized in that axial stops (18) are arranged between the tamper-evident ring (12) and the edge of the skirt (6) to which the ring is attached tamper-evident (12), and in that an undercut is made at the bottom of the tamper-evident ring, on the side opposite the bottom (4) of the cap. 2. Cap according to claim 1, characterized in that the undercut produced on the tamper-evident ring (12) is in the form of a peripheral projection (20) whose height decreases towards the skirt (6) of the plug.   3. Mold for producing a plug (2) comprising a cylindrical skirt (6) provided with at least one screw thread (8) and closed at one end by a bottom (8) as well as a tamper-evident ring (12 ) connected to a free end of the skirt (6) by breakable bridges (10), the tamper-evident ring (12) comprising tabs (14) which, turned inside and towards the bottom of the cap, are intended to cooperate with an annular rib located on the neck of a container intended to receive the stopper, having a fixed base (26) opposite a movable part or mold base (22) whose inner wall corresponds to the outer surface of the skirt (6) and bottom (4), a stripping part or deviating ring (24) whose internal surface corresponds substantially to the external surface of the tamper-evident ring (12) and a core (28) intended to be removed by a translational movement, without rotation, and whose outer surface corresponds nd on the inner surface of the bottom (4), the skirt (6) and the tamper-evident ring (12), characterized in that it also has drawers (30) placed between the mold bottom (22 ) and the deviating part (24) and which can be move substantially radially.   4. Method for producing a plug (2) comprising a cylindrical skirt (6) provided with at least one screw thread (8) and closed at one end by a bottom (4) as well as a tamper-evident ring (12 ) connected to a free end of the skirt (6) by breakable bridges (10), the tamper-evident ring (12) comprising tabs (14) which, turned inside and towards the bottom of the cap, are intended to cooperate with an annular rib located on the neck of a container intended to receive the stopper, characterized in that it comprises the following steps: injection of synthetic material into a closed mold having a fixed base (26) opposite a movable part or mold base (24), the inner wall of which corresponds to the outer surface of the skirt (6) and of the bottom (4), a stripping part or deviator ring (24), the inner surface of which corresponds substantially to the outer surface of the tamper-evident ring (12) and a core (28) whose outer surface corresponds to the inner surface of the bottom (4), the skirt (6) and the tamper-evident ring (12), as well as drawers (30) placed between the mold bottom (22 ) and the shedding part (24), b- withdrawal of the mold base (22) in an axial direction, c- withdrawal of the drawers (30) in a direction substantially radial with respect to the axis of the plug, displacement of the core ( 28) and the deviator ring (24) to release the stopper from the fixed base, e- relative movement of axial translation, without rotation, between the deviator part (24) and the core (28), the stopper being retained by the deviating part (24), f- relative movement in opposite direction of the core (28) and of the deviating part (24) so as to effect the reversal of the tongues (14) of the tamper-evident ring (12) and the ejection plug (2) out of mold.