GB2307901A - Child-resistant and tamper-evident screw closure - Google Patents

Abstract

A child-resistant screw closure for a container, such as a toothpaste tube, comprises a cap portion 40 and a flexible security ring 48, the cap being adapted for screw-threaded engagement with the container 10 and the ring being frangibly attached to the cap, the cap and ring having mutually engageable formations 56, 58 only disengageable by squeezing the security ring at pressure points 60, the ring further having formations engageable with the container which hold it captive and substantially immoveable on the container. Preferably the cap and ring are integrally moulded and the frangible attachment between them consists of four bridges 50 which renders the closure tamper-evident. Preferably the security ring has a discontinuous bead 53 with at least one gap (54, fig 5), and the container has a continuous chamfered bead (22, fig 2) and lugs (32, fig 2), so that the ring can snap engage the container and the gap or gaps engage with the lugs (32, fig 2), thus holding the ring captive and immobile. A sealing wad 46 or flexible sealing rib may be provided on the underside of the the cap. The container may be a plastic flexible tube or a can.

Description

"CHILD-RESISTANT SCREW CLOSURES FOR CONTAINERS" This invention relates to screw closures for packaging containers, especially (but not necessarily) squeeze tubes for liquid or pasty products.

The invention particularly concerns screw closures which are child-resistant (CR) in nature. CR screw closures are known, for example from GB patent specification No. 2004527, to have a flexible skirt or ring which is formed with inwardly projecting fins, lugs, teeth or like formations arranged for engagement with complementary formations which project outwardly from the neck of a container to which the closure is to be fitted.

When the closure is being screwed on the formations on the closure and the container ride over one another to allow the movement to occur. However, when an attempt is subsequently made to unscrew the closure the formations abut one another to prevent unscrewing unless the skirt or ring is deformed by squeezing sufficiently to allow the formations to pass one another. A closure of this kind is accordingly often referred to as a "Squeeze-andturn" closure, a nomenclature which will hereinafter be used for brevity.

In some circumstances it may happen that restraints imposed by the moulding operation upon the configuration of the container make it difficult or impossible to provide the container with the formation or formations required for engagement by a squeeze-and-turn closure.

The present invention enables this problem to be overcome. Accordingly from one aspect thereof the invention provides a child-resistant screw closure, which comprises a cap portion adapted for screw-threaded engagement with a container and a flexible security ring frangibly attached to the cap portion, the cap portion and the security ring having complementary formations adapted to prevent the cap portion from being turned in the unscrewing direction in relation to the security ring unless the security ring is manipulated to free the formations for relative movement, the security ring having means engageable with the said container when the closure is first fitted for holding the security ring captive on the container but substantially immoveable in relation thereto.

From a second aspect the invention provides a combination of a child-resistant screw closure and a container having a screw thread, the closure having a cap portion and a security ring frangibly and integrally attached together as a one-piece moulding, the cap portion having a screw thread for engagement with the screw thread of the container, the cap portion and security ring having complementary first formations which are mutually engageable to prevent unscrewing of the cap portion from the container unless the closure is first manipulated to prevent such engagement, the security ring and the container having complementary second formations engageable when the closure is first applied to the container to thereafter hold the security ring captive and substantially immobile on the container.

A squeeze tube fitted with a squeeze-and-turn CR closure in accordance with the invention will now be described, by way of example and with reference to the accompanying drawings. In the drawings: Fig.l shows the squeeze tube and closure in side elevation; Fig.2 shows a part of the tube which includes its dispensing nozzle, before the closure is fitted; Fig.3 shows the dispensing nozzle as seen from above, again before the closure is fitted; Fig.4 shows the closure as seen from above; Fig.5 shows the closure as seen from below, that is, looking into its mouth; Fig.6 shows the closure fitted on the dispensing nozzle, the closure being in section taken on the diametral plane VI-VI of Fig.4; and Fig.7 is a view generally corresponding to Fig.4 but as seen during an unscrewing operation.

Referring now to the drawings, a container for a liquid product such as a paste (e.g. toothpaste) is formed of a squeezable tube 10 and a threaded dispensing nozzle 14 (Fig.2) formed centrally on a moulded plastics headpiece 16 at one end of the tube body 17. The other end of the tube body, the lower end as shown, is closed by a fin seal 18 formed by heat-sealing together opposed marginal portions of the tube wall after filling with product.

The arrangement of the nozzle 14 is apparent from Figs. 2 and 3. The nozzle is formed with a conventional singl3e-start screw thread 20, and, below the screw thread, a continuous, outwardly projecting, peripheral bead 22 with an annular lower face 24 and a chamfer 26 around its upper surface.

The nozzle 14 rises from an upwardly facing annular face 28 of the headpiece 16 which is disposed in spaced opposition to the lower face 24 of the bead 22. Between the two annular faces 24, 28 the nozzle has a generally cylindrical face 29 which lies on the cylindrical envelope of the crests of the screw thread 20; together with the two annular faces the face 29 forms a peripheral recess 30 around the nozzle.

The headpiece 16 is formed by injection-moulding using a split outer mould (not shown). Two diametrically opposed lugs 32 of generally rectangular cross-section are formed within the recess 30 on the split line of the mould. They lie on a common diametral plane of the nozzle 14 and each have opposed, generally parallel side faces 34. Their upper, lower, and inner edges (not referenced) are rooted on the annular faces 24, 28 and the cylindrical face 29 respectively of the recess, their radial length to their free edges 36 being slightly less than the radial depth of the bead 22.

Referring now especially to Figs. 4 to 6, the closure 12 has a cap portion 40 arranged to close the nozzle 14 by engagement with the nozzle screw thread 20 in conventional manner. For that purpose it has a generally plane crown 42 (Fig.6), and a tubular depending skirt 44 which is internally formed with a screw thread 45 complementary to the nozzle screw thread. For sealing the container a wad 46 of a suitable material is provided on the underside of the crown. In the fitted position of the closure the cap portion lies closely adjacent the top of the bead 22 at the free bottom edge 47 of its skirt 44. In a modification (not illustrated) the wad is replaced by a flexible sealing rib or sealing ribs projecting integrally from its interior surface.

A security ring 48 is carried by the cap portion 40 by means of four peripherally spaced frangible bridges 50 which join the cap portion and the security ring integrally together as a single piece moulding. As will become apparent, the security ring provides child resistance for the closure by cooperation with the cap portion. The bridges 50 are clearly visible from the exterior of the closure - see Fig.l - so that the closure is not only child resistant but also is tamper-evident.

The security ring 48 is generally cylindrical and of larger diameter than the cap portion 40. It has an upper end portion 51 (Fig.6) which lies in concentric, spaced relation to a portion 52 at the bottom end of the cap portion. When the closure has been fitted to the tube its lower end, below the portion 51, surrounds the bottom end of the nozzle 14, that is to say, the part of the nozzle including the bead 22 and the recess 30.

Around its bottom edge the security ring 48 carries six part-annular bead portions 53 which project into the recess so as by engagement with the undersurface 24 of the nozzle bead 22 to hold the ring permanently captive on the tube. As will be described below, the bead portions are snap-engageable into the recess when the closure is first fitted,. For that purpose their undersurfaces 80 (Fig.6) are chamfered, to act as lead-in surfaces in cooperation with the chamfer 26 of the nozzle bead.

The bead portions 53 are spaced apart peripherally of the closure, and two of the gaps 54 between them accommodate the lugs 32 of the nozzle 24. By cooperaton of their side faces 34 with the side edges of the bead portions adjacent, the lugs therefore prevent any substantial rotational movement of the security ring on the nozzle.

In addition to their association by the frangible bridges 50 as described above, the security ring 48 and the cap portion 40 are also capable of cooperation with one another at pairs of complementary profiled lugs 56, 58 respectively. As can be seen in Figs. 4, 5 and 7, these lugs extend from their respective member 48, 40 into the annular space between those members.

As indicated in Fig.7, each lug 56 has a substantially radial trailing face 56A and an inclined leading face 56B; correspondingly, each lug 58 has a substantially radial trailing face 58A and an inclined leading face 58B. In the fitted closure the trailing faces 56A, 58A of the pairs of cooperating lugs 56, 58 abut one another to prevent the cap portion 40 from being unscrewed from the tube 10 unless the security ring is first squeezed by the user at opposed pressure points 60 as indicated by arrows A, so as to ovalise the security ring and move the ring lugs to a sufficiently large radius that they can pass the tube lugs.On the other hand, by virtue of their inclination the leading faces 56B, 58B allow the lugs 56, 58 to ride resiliently over one another so that the cap portion can be screwed back onto the tube after a dispensing operaton without any need for the ring to be deformed specially by the user.

In order to facilitate moulding of the closure 12 and simplify the tooling required, the frangible bridges 50 and the lugs 56, 58 are located in axial alignment with the gaps 54 between the bead portions 53 - see Fig.5 in particular.

For use, the closure 12 is applied by the packer as a single-piece moulding to the nozzle 14 by conventional capping equipment which screws it onto the nozzle to the fitted position illustrated in Figs. 1, 4 and 6. During application the discontinuous bead formed of the portions 53 snap-engages behind the bead 22, and the lugs 32 enter respective gaps 54 between the bead portions as the fitted position is approached. The circumferential length of the gaps is sufficient to enable this to occur; likewise, the bridges 50 are sufficiently robust to transmit the torque required to achieve the snapengagement.

After the initial fitting by the packer the lugs 32 and bead 22 of the nozzle 14 will hold the security ring 48 loosely but permanently captive on the tube and prevented from any substantial movement, axial or rotational.

For operation by the consumer to allow the tube 10 to be opened and subsequently reclosed, the closure 12 operates as a conventional squeeze-and-turn closure except that the security ring 48 remains on the tube. It will be appreciated that for the first opening operation sufficient torque has to be applied to the cap portion 40 to break the bridges 50 before unscrewing can occur.

In the described embodiment the bead 22 and the lugs 32 are robust, and simple in shape. In particular, they can be subject to wide moulding tolerances. In comparison, lugs equivalent in function to the lugs 56, 58 but provided on the nozzle 14 for direct engagement with the closure would require much tighter tolerances which would be difficult or impossible to achieve in the moulding operation. The closure/tube combination shown and described overcomes this problem and additionally provides tamperevidence in the form of the frangible bridges 50. However, the invention should be understood as applicable to containers other than tubes (e.g. cans), whether tamper-evident or not.

Claims (6)

CLAIMS:

1. A child-resistant screw closure, which comprises a cap portion adapted for screw-threaded engagement with a container and a flexible security ring frangibly attached to the cap portion, the cap portion and the security ring having complementary formations adapted to prevent the cap portion from being turned in the unscrewing direction in relation to the security ring unless the security ring is manipulated to free the formations for relative movement, the security ring having means engageable with the said container when the closure is first fitted for holding the security ring captive on the container but substantially immoveable in relation thereto.

2. A closure as claimed in Claim 1, wherein the cap portion and the security ring are frangibly attached together by a plurality of spaced frangible bridges which are visible from outside the closure, thereby rendering the closure tamper-evident.

3. A closure as claimed in Claim 1 or Claim 2, wherein the said means engageable with the container comprises a snap-engagement bead projecting from the interior of the security ring.

4. A closure as claimed in Claim 3, wherein the snapengagement bead is discontinuous and formed with at least one gap.

5. The combination of a child-resistant screw closure and a container, the closure being as claimed in Claim 4 and the container having a peripheral bead beneath which the bead of the closure is snap-engageable, and a projection which, on such snap-engagement enters into the said gap of the snap-engagement bead of the security ring.

6. The combination of a child-resistant screw closure and a container having a screw thread, the closure having a cap portion and a security ring frangibly and integrally attached together as a one-piece moulding, the cap portion having a screw thread for engagement with the screw thread of the container, the cap portion and security ring having complementary first formations which are mutually engageable to prevent unscrewing of the cap portion from the container unless the closure is first manipulated to prevent such engagement, the security ring and the container having complementary second formations engageable when the closure is first applied to the container to thereafter hold the security ring captive and substantially immobile on the container.