US20030102280A1

US20030102280A1 - Device for plugging a threaded collar using a cap with a tamperproof ring

Info

Publication number: US20030102280A1
Application number: US10/169,949
Authority: US
Inventors: Philippe Odet; Niels Damkjaer
Original assignee: Individual
Current assignee: Tetra Pak Closures Developpement SA
Priority date: 2000-01-14
Filing date: 2001-01-09
Publication date: 2003-06-05
Also published as: EP1246760A1; FR2803830B1; JP2003519602A; AU2001231862A1; WO2001051375A1; FR2803830A1

Abstract

The tamperproof closing device for a receptacle having a threaded collar comprises a screw cap (1) consisting of a bottom (8) and a cylindrical skirt (9) having inner threading for co-operation with the corresponding threading (5) on the collar (2) and extended by a tamperproof ring (13) which is attached by frangible means (20). The collar has a plurality of outer radial notches arranged at the base thereof. Said notches are circumferentially oriented and the ring comprises a plurality of inner radial reliefs (15) whose profile is complementary to that of the notches (7). The orientations and dimensions of the notches (7) and reliefs (15) are determined in such a way that the second items can pass onto the first items in the direction of screwing as a result of elastic deformation of the constitutive material and can prevent the same from occurring in the opposite direction. The reliefs (15) are formed on an annular lip (14) which is turned back and originates from the tamperproof ring (13). When it leaves the mould, said lip (14) forms an annular truncated appendix converging slightly towards the inside and bearing the reliefs on the outside (15).

Description

The present invention relates to a tamperproof closure device for a receptacle with threaded collar (which is directly formed on the receptacle or is added thereto) comprising a screw cap presenting a bottom and a cylindrical skirt internally threaded to cooperate with the corresponding thread made on the collar, and extended by a tamperproof ring attached by frangible means, the collar presenting at its base a plurality of outer radial notches oriented circumferentially and the ring presenting a plurality of inner radial reliefs whose profile is complementary to that of the notches, the orientations and the dimensions of the notches and of the reliefs being determined so as to allow the passage of the latter on the former in the direction of screwing thanks to the elastic deformation of the constituent material, and to oppose this passage in the opposite direction. This deformation makes it possible to position the cap and its tamperproof ring by screwing. In the event of opening or attempt to open the cap by unscrewing, the reliefs of the tamperproof ring abut on the notches and oppose rotation of the ring, in which case their frangible links with the skirt of the cap break.

Such a device is well known in the prior art and is illustrated for example in document EP 0 261 037A. Similar devices are currently used in the food industry, particularly for drinks, as described in EP 0 330 964. In numerous cases, it is important to guarantee not only that the cap has not been opened and the contents of the recipient emptied or modified, but also that the asepsis of the packaging has been conserved. Now, in certain devices, this asepsis can be interrupted even without breaking the tamperproof ring, as a very slight unscrewing of the cap through an angle of a few degrees (for example 5°), which is generally insufficient to provoke with certainty the abutment of the reliefs of the cap against the notches of the collar and the rupture of the frangible links (in certain devices on the market, the cap must be unscrewed through at least 90° before the tamperproof ring is broken), but may be sufficient to destroy the tightness and asepsis of the closure. It is therefore important to design a closure device which makes it possible to solve this problem without excessive complication of construction.

On the other hand, in the known devices, the reliefs of the ring must be moulded inside it, which complicates moulding of the cap and increases the cost price thereof, especially if it is desired to adapt the notches and the reliefs to the solution of the problem of asepsis mentioned above.

It is an object of the invention to propose a closure structure of the general type described hereinabove, which can be moulded and unmoulded more easily and thus allow the cost price of the cap to be reduced without sacrificing the quality of the closure; on the contrary.

The object of the invention is attained in that the inner reliefs of the tamperproof ring are no longer formed directly on its inner periphery but on an annular lip which is turned back and originates from the ring, this lip forming, when it leaves the mould, an annular truncated appendix converging slightly towards the inside and bearing the reliefs on the outside, while it is provided to space the reliefs of the ring and the notches of the collar apart by different pitches p and q, chosen to ensure the engagement of at least one notch with at least one relief, with an angular periodicity a preferably less than 3°. In that case, it is easy to form the reliefs by moulding outside the lip before turn-back, at the same time as the cap itself is moulded, and to proceed with turning back the lip preferably prior to positioning the cap on the collar. Such a lip with turn back attached to a tamperproof ring is known per se (cf. for example document FR 2 768 131 A, lip 31), but it was used up to now only for axially locking the tamperproof ring under a counter-ring of the collar. One advantage resulting from the placing of the reliefs on the lip with turn-back comes from the suppleness of the latter and from its facility of deformation which renders the screwing operation of the cap easier because the screwing couples are reduced. The continuous nature of the lip induces a circular distribution of an effort of radial expansion undergone by the lip in the event of a fraudulent attempt being made to open the cap. Thanks to the increased simplicity in manufacturing the cap of the invention, it is possible to more easily adapt the notches and relief so as better to guarantee the asepsis of the closure, even for very small angles of unscrewing, for example of the order of 3°.

Advantageously, the values of pitches p and q differ from one another by said angle a, a being a sub-multiple of the pitches p and q of said reliefs and notches (i.e. p=m×a and q=n×a, m and n being whole numbers with m−n=+/−1), with the result that, with this angular periodicity a, there is always at least one and preferably two engagements between notches and reliefs, the other notches and reliefs in that case not being engaged. The value of a is chosen to be low, for example less than 3° to ensure that the angle of unscrewing which brings about rupture of the tamperproof ring will be less than a value (for example 3°) which would lead to the loss of asepsis.

The notches and the reliefs are advantageously formed on only a part of the periphery of the collar and of the tamperproof ring, preferably substantially on two opposite quadrants.

Other advantages and characteristics of the invention will be evident on reading the following description with reference to the accompanying drawings, in which: [0008]
FIG. 1 shows in perspective with parts torn away, a form of embodiment of a closure according to the invention screwed on its collar. [0009]
FIGS. 2 and 3 schematically show in radial section the skirt with reliefs according to the invention, respectively before and after turn-back. [0010]
FIG. 4 is a schematic plan view showing the cooperation of the reliefs of the skirt of FIGS. 2 and 3 with the collar with which the closure fits. [0011]
FIG. 5 shows the collar of the closure of FIG. 1 in perspective. [0012]
FIG. 6 shows the closure itself of FIG. 1, in perspective. [0013]
FIG. 7 shows the closure and the collar, in section in plane E-E of FIG. 1.[0014]
FIG. 1 shows a cap [0015] 1 intended to be screwed on the collar 2 of a receptacle.
The collar [0016] 2 (cf. FIGS. 1, 5 and 7) comprises a cylindrical section 3 rising from an annular edge 4 The section 3 bears on the upper part of its outer periphery a thread 5 for screwing, and, on the lower part of this periphery, an annular rib 6 below which are formed projections 7 forming notches, distributed over the periphery or only a part thereof (substantially on two opposite quadrants in the example of embodiment illustrated).
The cap, moulded for example from polyethylene (PE), comprises (cf. FIGS. 1, 6 and [0017] 7) a bottom 8 from which issues a cylindrical outer skirt 9 comprising on its outer periphery flutings for gripping or similar reliefs 10 and on its inner periphery a screw thread 11 intended to cooperate with the thread 5 of the collar 2. The flutings 10 stop at the level of an annular excess thickness 12 below which is formed the tamperproof device comprising a tamperproof ring 13 attached to the skirt by breakable bridges 20. Issuing from the ring 13, the turned back lip 14 bears reliefs 15 which are oriented radially towards the inside (after turn-back of said lip) and cooperate with the notches 7 of the collar 2 in order to prevent rotation of the cap 1 on the collar 2. The turned back lip 14 is housed beneath the annular rib 6 of the collar. In manner known per se, the cap also comprises, issuing from the bottom 8, a sleeve 21 for tightness cooperating with the interior of the collar 2.
FIG. 2 schematically shows the position of the [0018] lip 14 at the bottom of the ring 13 on leaving the mould, the lip 14 in that case forms a supple, annular, truncated appendix converging slightly towards the inside and bearing the reliefs 15 outside. The lip 14 converges towards the bottom of FIG. 2, i.e. opposite the bottom 8 of the cap. When the cap is being placed on the collar, the lip is turned back as known per se, which has the effect of exposing its reliefs 15 opposite the notches 7 of the collar 2 (which has been shown as formed directly on the receptacle in FIG. 3).
FIG. 4 very schematically shows the functioning and cooperation of the [0019] reliefs 15 with the notches 7. Only four pairs of reliefs and notches in mesh have been shown for simplification. These pairs function like pawls in order to prevent rotation of the cap on the collar in the direction of unscrewing but to allow the initial screwing thanks to the cooperation of the ramps formed on the notches and the reliefs.
In fact and as illustrated precisely in FIG. 7, it is preferred to arrange the [0020] notches 7 and the reliefs 15 in a sufficient number to allow an engagement of the notches and the reliefs at regular and not too large angles (in order to preserve safety from asepsis); arrangements are such that the reliefs 15 do not all engage at the same time with all the notches 7, in order to avoid the burst of the cap which might result when all the reliefs overlap all the notches and to minimise the frictions. Finally, the respective pitch of the notches and the reliefs is different and calculated so as to make it possible to ensure an engagement of notches and of reliefs at a small pitch equal to the difference of the respective pitches. As the example of FIG. 7 shows, while the notches 7 are formed regularly every 10° (over two opposite quadrants of the collar), the reliefs 15 are formed with angles of 12.5°. More precisely, the collar comprises over a little more than a quadrant nine notches 7 a to 7 i, formed identically from a ramp 16 and a stop face 17 except for the notch 7 b whose ramp is longer; the consecutive stops are spaced apart by 10° except between the stop faces of the first two notches 7 a, 7 b where the angular space is 20°. The cap comprises a first relief 15 a extending over 10° and followed by eight reliefs 15 b to 15 h extending over 12.5°, said reliefs all also comprising a ramp 18 and a stop face 19. In the position shown in FIG. 7, it is seen that only the stop faces of couples 7 a, 15 b and 7 e, 15 f are in abutment, while the other pairs cannot coincide and will therefore bring about a slight expansion of the cap at their level. As may be seen in FIG. 7, the following engagement, if one continued to screw the stopper on the collar, would be 7 d with 15 e (after a pitch of 2.5°), then 7 c with 15 d, then 7 b with 15 c. In this way, the pitch p of the reliefs is 12.5°, the pitch q of the notches is 10°, and the pitch a which results therefrom for the engagements between notches and reliefs is 2.5°. The notch 7 with longer ramp tends to retain the cap to the rear and therefore to reduce the clearance of the cap on the collar.

Claims

1. Tamperproof closure device for a receptacle with threaded collar comprising a screw cap (1) presenting a bottom (8) and a cylindrical skirt (9) internally threaded to cooperate with the corresponding thread (5) made on the collar (2), and extended by a tamperproof ring (13) attached by frangible means (20), the collar presenting at its base a plurality of outer radial notches (7) oriented circumferentially and the ring presenting a plurality of inner radial reliefs (15) whose profile is complementary to that of the notches, the orientations and the dimensions of the notches (7) and of the reliefs (15) being determined so as to allow the passage of the latter on the former in the direction of screwing thanks to the elastic deformation of the constituent material, and to oppose this passage in the opposite direction, said reliefs (15) being formed on an annular lip (14) which is turned back and originates from the tamperproof ring (13), characterized in that said lip forms, when it leaves the mould, an annular truncated appendix converging slightly towards the inside and bearing the reliefs (15) on the outside, and in that the notches (7) and the reliefs (15) are formed with different respective pitches q and p such that they ensure the engagement of at least one notch (7 a) with at least one relief (15 b) with an angular periodicity a preferably less than 3°.

2. Device according to claim 1, characterized in that the reliefs (15) are formed by moulding on the outside of the lip (14) before turn-back.

3. Device according to either one of the preceding claims, characterized in that the notches (7) and the reliefs (15) are formed on only a part of the periphery of the collar (2) and of the tamperproof ring (14), preferably substantially over two opposite quadrants.

4. Device according to any one of the preceding claims, characterized in that the pitches p and q are whole multiples of the periodicity of engagement a and differ from one another by the value a.

5. Device according to claim 4, characterized in that the respective pitches of the notches (7) and of the reliefs (15) are such that they ensure the engagement of at least one notch (7 a) with at least one relief (15 b) with a periodicity a preferably less than 3°.

6. Device according to claim 5, characterized in that the pitches p and q are whole multiples of the periodicity of engagement a and differ from one another by the value a.