GB2419587A

GB2419587A - Child resistant closure with deformable skirt

Info

Publication number: GB2419587A
Application number: GB0521843A
Authority: GB
Inventors: Dean Walding
Original assignee: Dragon Plastics Ltd
Current assignee: Dragon Plastics Ltd
Priority date: 2004-10-26
Filing date: 2005-10-26
Publication date: 2006-05-03
Anticipated expiration: 2025-10-26
Also published as: GB2419587B; GB0521843D0

Abstract

A child-resistant closure for a screw-threaded container comprises a cap 12 having an annular skirt 14 around a lower portion thereof, the skirt having at least one retaining feature which in use cooperates with a complementary feature on the container to prevent the fully-fitted cap being moved in a closure removal direction unless the skirt has been deformed by manipulation in a predetermined manner so as the separate the one retaining feature and the complementary feature, the skirt being connected to the cap by resiliently deformable arms 40. The resiliently deformable arms are preferably v-shaped living hinges. In use, to remove the closure the user grips a pair of tabs 38 so as to deform the skirt and allow the closure to be rotated.

Description

Child Resistant Closure The present invention relates to a child resistant

closure and in particular to a child resistant cap for a container.

It is known to provide child resistant closures to containers for, for example, medicines and noxious substances such as cleaning products and garden chemicals. The child resistant closure typically includes a blocking means which prevents the closure from being removed from the container unless the closure is manipulated in a certain manner.

According to the present invention there is provided a child resistant closure for a screw-threaded container, the closure comprising a cap having an annular skirt provided around a lower portion thereof, the skirt being provided with at least one retaining feature cooperable with a complementary feature of the container to prevent movement 1 5 of the closure in a removal direction once the closure has been fully fitted to the container, the skirt being resiliently deformable by manipulation thereof in a predetermined manner to move the retaining feature away from the complementary feature of the container, wherein the skirt is connected to the cap by resiliently deformable arms.

The deformable arm may comprise a curved or serpentine arm, or a living hinge having a first and second leaf portions joined at an elbow.

The deformable arm serves to both connect the skirt to the cap and to provide a restorative force which urges the skirt to resume its initial configuration after it has been deformed to move the retaining feature clear of the complementary feature of the container.

The living hinge is arranged between the skirt and cap such that it is caused to fold about the elbow upon deformation of the skirt. In a preferred embodiment the living hinge is substantially V' shaped in crosssection wherein the first leaf portion extends from the skirt towards the cap, the second leaf portion extends from the cap towards the skirt, and the elbow is provided intermediate the skirt and cap. The V' shape of the hinge may be downwardly directed with respect to the top of the cap. Alternatively the 1V' shape of the hinge may be upwardly directed. It will be appreciated that folding of the hinge in the manner described causes energy to be stored in the hinge.

In a preferred embodiment the closure is provided with two retaining features and two deformable arms. The retaining features and arms are spaced alternatively and equidistantly about the closure. The skirt is preferably provided with tabs grippable by a user to deform the skirt in the predetermined manner. The tabs are preferably located adjacent the arms. The retaining features may comprise inwardly directed barbs of the skirt. The closure is preferably of a unitary construction and manufactured from a plastics material by an injection moulding operation.

In a preferred embodiment the arcuate gap between the skirt and cap is not of a constant width. Typically the gap is at a minimum in the region adjacent the or each retaining feature, and at a maximum adjacent the or each living arm.

In one embodiment, the closure has two opposite arms on a first diameter and two opposite retaining features on a second diameter orthogonal to the first diameter. Two approximately semi-circular gaps are defined which reduce from a maximum dimension at the opposite ends to a minimum dimension at the middle, adjacent a respective retaining feature. The width of the gap at the ends may be at least 30% greater than the width at the middle.

This arrangement has the advantage that the gap at the middle is small, and tends to hide the associated retaining feature from view. Furthermore the gap at the ends is large and tends to increase the available deformation of the skirt, whereby the retaining feature is released.

A simple living hinge having two leaf portions is preferred. However multiple leaf portions may be provided if desired. For example a double hinge may have apices facing up or down, or have one apex facing up and one apex facing down.

Alternatively the leaf portions may extend in the direction of the axis of screw threading so as to zig zag between skirt and cap when viewed from above.

Similarly curved or serpentine arms may extend in the direction of the screw axis, or perpendicular thereto so long as they do not define return edges which prevent mould separation.

An embodiment of the present invention will now be described with reference to the accompanying drawings in which: Figure 1 shows a perspective view from above and to one side of a closure according to the present invention; Figure 2 shows a top plan view of the closure; Figure 3 shows a bottom plan view of the closure; Figure 4 shows a perspective cross-sectional view indicated along the line A-A in figure 3; Figure 5 shows a partial cross-sectional view indicated by arrow B-B in figure 3.

Figure 6 is a partial transverse section showing a variable gap between the skirt and cap; Figure 7 is a partial axial section showing an alternative living hinge.

Figure 8 is a partial axial section showing another alternative living hinge.

Figure 9 is a partial axial section showing yet another alternative living hinge.

Figure 10 is a partial transverse section showing yet another alternative living hinge.

Figures 11-12 show other variants as a partial axial section.

Figures 13-14 show other variants as a partial transverse section.

Referring to the figures there is shown a child resistant screw type closure, generally designated 10, for a container (not shown) with a complimentary screw thread such as a bottle. The closure 10 comprises a cap 12 and a skirt 14. The cap 12 comprises a wall 16 and a top 18 which define a cavity 19. The exterior 20 of the wall 16 is provided with a plurality of grooves 22 which, in use, assist in a user maintaining their grip on the cap 12. The interior 24 of the wall 16 is provided with a threadform 26. The top 18 of the cap 12 is provided with indicia 28 to inform the user as to how to remove the closure 10 from the container.

The skirt 14 comprises a substantially circular annular member 30 having an inner face 32 and an outer face 34. The inner face 32 is provided with a pair of barbs 36 spaced equidistantly from one another. The barbs 36 include a ramp surface 37 and a mating surface 39. In use, the barbs 36 co-operate with complementary projections of the neck of the bottle as will be described in greater detail below. The outer face 34 of the annular member 30 is provided with a pair of grippable tabs 38 which, in a similar manner to the barbs 36, equidistantly spaced from one another. The barbs 36 and tabs 38 are spaced rotationally on the annular member 30 so as not to be in register with one another. In the embodiment shown the barbs 36 and tabs 38 are spaced rotationally by degrees.

The skirt 14 is connected to the cap 12 via a pair of living hinges 40 which extend between the inner face 32 of the annular member 30 and the exterior 20 of the wall 16.

The cap 12 is manufactured from a plastics material by an injection moulding operation. It will thus be appreciated that the hinges 40 are formed integrally with the cap 12 and skirt 14. Each hinge 40 is substantially V' shaped in cross-section as can be seen in figure 5 and comprises a first and second leaves 42,44 defining the arms of the V which meet at an elbow 46 defining the base of the V'. Each hinge 40 is located between the cap 12 and the skirt 14 adjacent a tab 38.

In use, the cap 12 may be fitted to a bottle in a conventional manner. The cap 12 is positioned such that the bottle opening is received within the cap cavity 19. The cap 12 rotated until the threadform 26 thereof engages with the complementary threadform of the bottle. Continued rotation of the cap 12 advances the cap 12 onto the bottle. As the cap 12 approaches its fully fitted position the barbs 36 of the skirt 14 encounter projections of the bottle neck. Typically the projections of the bottle neck mirror the shape of the cap barbs 36 in that they are provided with a ramp surface and a mating surface. The bottle neck projections are arranged such that their ramp surface faces the ramp surface 37 of the cap barbs 36. As the ramp surfaces engage one another the annular member resiliently deforms to permit the barbs 36 to ride up and over the bottle projections. Once clear of the projections the annular member returns to its original substantially circular shape with the result that the mating surfaces 39 of the barbs 36 face and overlap the corresponding mating surfaces of the bottle projections.

Any attempt to remove the closure 10 by gripping the cap 12 and twisting it in the removal direction of the threadforms results in the mating surfaces being driven against one another and rotation of the closure 10 relative to the bottle prevented. In order to remove the closure 10 a user is required to grip the tabs 38 to deform the annular member 30. In gripping the tabs 38 and moving the annular member 30 in the region thereof towards the cap 12 the annular member is deformed from its substantially circular shape to an elliptical shape. The portions of the annular member 30 having the barbs 36 are thus moved away from the cap 12 and bottle neck and lifted clear of the bottle projections. The cap 12 can then be rotated in its removal direction.

Gripping of the tabs 38 in the manner described above to deform the shape of the annular member results in compression of the hinges 40. Each hinge 40 folds about the elbow 46 with the result that the leaves 42,44 are moved towards one another. The folding of the hinge 40 stores energy which urges the annular member 30 back to its substantially circular shape when the user's grip on the tabs 38 is released.

The provision of the living hinges 40 connecting the skirt 14 to the cap 12 has the result that moulding of the closure 10 utilises less material than known closure configurations.

The closure 10 according to the present invention is thus lighter and cheaper to manufacture than conventional closures.

With reference to Figure 6 the skirt 14 is connected to the cap 12 by opposite living hinges 40 (one only illustrated). On the orthogonal diameter are provided opposite barbs 36 (one shown) for engagement with a bottle neck. The gap 50 between skirt and cap is greatest in the region of the tabs 38, and least adjacent the barbs 36. In the illustrated arrangement the skirt has an L' section in the vicinity of the barb 36 so as to hide the barb from view and to increase the strength and rigidity thereof. Furthermore, by relatively increasing the gap adjacent the tabs 38, the potential deformation of the skirt is increased. It will be appreciated that in this embodiment the downwardly depending portion of the skirt is of constant thickness, whereas the transverse portion varies in width according to the desired gap.

In Figure 6, the dimensions are somewhat exaggerated to best illustrate this aspect, and it will be appreciated that the cap is symmetrically moulded to give opposite narrow gaps adjacent the opposite barbs.

Figures 7-9 show variations of living hinge which may be desired to give particular operating characteristics. Two connected living hinges may have different spring rates if desired.

Figure 10 shows how leaves may be moulded in the direction of the rotational axis of the cap. A double living hinge 51 has opposite apices 52 which point generally circumferentially. The leaf portions of the hinge are generally arcuate so as to give maximum movement of the skirt 14 towards the cap 12 in the direction of arrow 53.

Typically each leaf portion may be as deep as the skirt, but clearly this is a matter of design. A single living hinge with single apex is of course an alternative.

Figures 11-14 show variants of the invention with curved or serpentine arms which are stiff enough to resiliently return the skirt 14 to its original shape once the deforming load is relieved. As with other embodiments, stiffness is a function of material and material thickness, but certain shapes are inherently adapted to give a low load so that the choice available to the mould designer is sufficient given that some compromises may be required to ensure even cooling of a freshly moulded cap. The width of each arm can also be selected to suit design requirements.

As will be appreciated, the mould separation direction is up and down (as viewed) for the embodiments of Figures 7-9, 11 and 2, and perpendicular to the drawing in the case of Figures 6, 10, 13 and 14.

Claims

Claims 1. A child resistant closure for a screw-threaded container, the

closure comprising a cap having an annular skirt provided around a lower portion thereof, the skirt being provided with at least one retaining feature cooperable with a complementary feature of the container to prevent movement of the closure in a removal direction once the closure has been fully fitted to the container, the skirt being resiliently deformable by manipulation thereof in a predetermined manner to move the retaining feature away from the complementary feature of the container, wherein the skirt is connected to the cap by resiliently deformable arms.
2. A closure according to claim 1 wherein said deformable arms are curved.
3. A Closure according to claim I wherein said deformable arms are serpentine.
4. A closure according to claim I wherein said deformable arms each comprise a living hinge having first and second leaf portions joined at an elbow.
5. A closure according to claim 4 wherein each living hinge is substantially V' shaped in cross-section, the first leaf portions extending from the skirt towards the cap, the second leaf portions extending from the cap towards the skirt, and the elbows being provided intermediate the skirt and cap.
6. A closure according to claim 5 wherein the apex of the V' shape of each hinge is downwardly directed with respect to the top of the cap.
7. A closure according to claim 5 wherein the apex of the V' shape of each hinge is upwardly directed with respect to the top of the cap.
8. A closure according to any preceding claim and having two retaining features and two deformable arms, the retaining features and arms being spaced alternately and equidistantly about the closure.
9. A closure according to any preceding claim wherein said skirt is provided with tabs grippable in use to deform the skirt in the predetermined manner.
10. A closure according to claim 9 wherein a respective tab is located immediately adjacent a respective arm.
11. A closure according to any preceding claim wherein the arcuate gap between the skirt and cap is not of a constant width.
12. A closure according to claim 11 wherein said gap is at a minimum in the region adjacent a retaining feature, and at a maximum adjacent each resilient arm.
13. A closure according to any of claims 1-4 and having two opposite arms on a first diameter and two opposite retaining features on a second diameter orthogonal to the first diameter, the skirt and cap defining two approximately semi-circular gaps which reduce from a maximum dimension at the opposite ends to a minimum dimension at the middle, immediately adjacent a respective retaining feature.
14. A closure according to claim 13 wherein the width of the gap at the ends is at least 30% greater than the width at the middle.
15. A child resistant closure substantially as described herein with reference to the accompanying drawings.