GB2269811A - Hinged closure - Google Patents

Abstract

A closure comprises a flexible panel 1 attached to a container 2 or cap by one or more hinges 3, the hinge or hinges defining an area which is smaller than the area of the panel and the panel being outwardly convex when in the open position and inwardly concave when pushed into the closed position (figure 2). The rim 7 of the container may be strengthened and may also deform to aid movement of the panel and to give a snap action. The panel may have longitudinally extending reinforcing grooves or ribs. The closure may be integral with the container or form part of a cap (figure 11). It may also have a sealing device such as a lip (23, figures 8 and 9) or rib and groove seal, and may have a tamper evident tear off seal which must be removed before opening. The closure may be child resistant (figures 12a-12e) and comprise a cap, biased by a spring, rotating on the closure. The closure may be manufactured from plastics, metal, cardboard, paper or a composite of these and may include a tab 27. <IMAGE>

Description

SNAP ACTION CLOSURES FOR CONTAINERS Field of the invention The invention relates to closures commonly used for sealing bottles, tubes, and jars, in which a hinged cap moulded integrally with the body of the closure has an "over-centre" action, which biasses the closure to the open or closed position.

In a typical prior art construction, a hinge connects the body and cap, together with a ligament which has its attachment points located so that its longitudinal axis moves to one side or the other of the hinge axis as the cap is moved through a mid-way position. During the initial part of the opening or closing movement, the ligament is stretched, and the energy stored therein is used to assist the opening or closing action as the cap passes its mid-way position, by virtue of the offset axis. This type of action, sometimes known as 'over-centre', can provide a very strong closing force so that the closure snaps shut after passing the centre position.

Since the invention of this type of closure by Zeller, a number of other closures with a similar action have been designed, but using an over-centre cam to achieve the snap action effect; they are usually less efficient than the ligament type because of friction between the co-operating surfaces of the cam and abutment.

Whilst this type of closure is not necessarily more effective than screw closures for example, the feel of a snap action closure is well liked by the consumer, it may be operated by one hand, and closures having these features have enjoyed considerable commercial success.

A household, food or cosmetic product may have little real technical or intrinsic advantage over a competitive product, and manufacturers have to resort to innovative packaging to promote their products. Most of the important patents covering snap action closures have expired, and such closures have become commonplace. Consequently, there is an urgent need for a closure having the practical and tactile advantages of prior art products, but employing a new principle of operation: this will result in visually different packaging with the attendant commercial advantages.

Many billions of packs are used annually for products such as milk or soft drinks, and small savings on the cost of the pack are important. Composite cardboard cartons have been used extensively for low cost packaging, mainly because they are formed, filled and sealed (no separate closure) from the sheet material on the producer's site, and there is no need for extensive storage and transport of empty containers. However, cartons have been criticised because they are difficult to recycle, difficult to open (particularly for the handicapped), and are not re-closeable. Similarly, glass bottles, whilst being recyclable, are relatively heavy, have to be transported to and stored at the producer's factory, and sterilized before use.

As a result, there is a trend away from these traditional packs towards blow-moulded plastic containers, and the larger producers can mould the pack on site, which method enjoys similar benefits to on-site carton making. However, a closure has to be manufactured, stored, sterilized and fitted to the filled pack, and the plastic container is not as economical as the carton. It is possible to form, fill, and seal such plastic containers, but the equipment is very costly and this method is not used for low profit margin products. There is therefore a need for a plastic pack which is mouldable on the producer's or filler's site, recyclable, easily sealed without an additional closure, re-closeable, easy to use, and which uses conventional moulding and filling machinery.

Summary of the Invention The present invention makes use of an over-centre principle in a one piece snap action closure. The closure may be configured to be operated with one hand, and may be manufactured integrally with a container, or as a separate component for attachment to a container.

In one embodiment, the closure is integral with a container, preferably with one or more curved walls. Part of the wall at the dispensing end of the container is flexible, and may be defined by a thin section which acts as a hinge. The hinge also defines an aperture through which the flexible panel must pass, and the dimensions of the aperture are slightly smaller than those of the flexible panel. By pressing on the flexible section when it is convex and in the open position, it is deformed to pass through the smaller aperture, so as to reverse its curvature and snap into a concave part of the container, thus closing it. Alternatively, the aperture may stretch sufficiently to allow the flexible panel to pass through with less deformation. When the closure is opened, a similar snap action occurs, and in either position, there is a strong bias holding the flexible panel.

In another embodiment, the closure is a separate component for attaching to a container, and uses the same principle as described above.

All embodiments may have the closure heat-sealed, with lines of weakness defining a tear-off portion for security and tamper evidence.

Description of the drawings Figure 1 is a perspective sketch of the closure in its simplest form, in the closed position.

Figure 2 is a similar sketch showing the closure in the open position.

Figures 3 & 4 are diagrammatic plan views of a cross-section through a simple circular closure in the closed and open positions respectively.

Figure 5 is a cross-section through a non-circular closure in the open position, and figure 6 shows a similar closure in the closed position.

Figure 7 illustrates a typical hinge section Figures 8 & 9 are longitudinal sections through a typical closure, shown open and closed respectively, in which a sealing lip is incorporated.

Figure 10 illustrates a bottle having an integral closure.

Figure 11 shows the invention applied to a screw top for fitting to a container.

Figures 12a to 12e show the device of the invention fitted with a safety cap, which assembly constitutes a child resistant closure. Figure 12a is a longitudinal section through the closure as shown in figure 12b. Figure 12c is a plan view on the closure in its unoperated, child-resistant position.

Figure 12d shows the cap rotated in direction of arrow X so as to align a finger groove with the closure operating tab, and figure 12e shows the operating tab pushed forward to open the closure.

Description of the invention Referring to figures 1 and 3, the hollow, approximately circular neck of a container 2 has a thin flexible section 1, which is a curved and approximately triangular plate in developed shape, and which is further defined by a thinner hinge section 3. When the upper part of section 1 is pressed towards the hollow neck of the container 2, it flexes at the hinge section 3, and simultaneously, the rim of the neck 4, which may have a strengthening rim 7, is forced apart because the developed length of the top of the thin flexible section is greater than the "diameter" of the rim 4 through which it has to pass. As the section 1 is forced beyond its flat position, the force exerted by the rim 4 on the edges of the section 1 causes said section to adopt a curvature opposite to its original, and to snap into the hollow of the neck, as shown in figures 2 and 4. Preferably, the section 1 is thin enough and of a suitable length to conform to the profile of the rim 4 so as to effect a reasonable seal.

The embodiment described heretofore is for illustration purposes only, and in practice it could be difficult to force the semi-circular rim apart sufficiently to allow section 1 to pass without severe buckling and possible damage. Accordingly, a modified section is shown in figure 5, in which it may be seen that the thin flexible section 20 may be more readily flattened because it is only slightly longer than the shortest distance between the ends of rim 21, and rim 21 does not have to distort'excessively to allow the section 20 to pass through the ends. Figure 6 shows the same closure in the closed position.

A typical hinge section is shown in figure 7. The working part 22 of the hinge should be as thin as the process, material and application permits, and to the design recommendations given by the material supplier.

The embodiments described thus far will achieve only a moderate seal, suitable for powders, granules and tablets for example, but unlikely to be liquid tight. Accordingly, figures 8 and 9 show longitudinal sections through the closure which has a flexible sealing lip 23 integral with rim 25. When the thin flexible section 24 is pressed into the hollow of the neck 26 as previously described, it will first make contact with the edge of the sealing lip 23. The lip 23 will flex and achieve a reasonable temporary seal against section 24, and the closure may be left in this position if desired. However, by applying more pressure to the section 24, the rim of the said section may be snapped behind the sealing lip 23, thus improving the security of the closure.A number of alternative profiles would suffice to achieve the same effect, such as the rib and groove seal commonly used for securing and sealing polyethylene bags. An enhancement (not shown) is to provide the closure with a tear-off seal, which must be removed before the closure can be opened; this will provide tamper evidence and a further improved seal. The sealing device may be integral with the closure as when heat-sealing after filling, or added to it.

Although the present invention describes a snap action closure in which a relatively thick curved member must flex to permit the thin section to pass, if the thin section is very flexible, or the curved member is very stiff, said member will not distort enough to permit a simple flexing and reverse curvature of the thin section. In this case, the thin section will assume an "S", "W", or other shape during transition from open to closed position and vice versa. The thin flexible section may have longitudinal grooves in the surface or ribs to increase flexibility in circumferential direction whilst maintaining a higher rigidity in the longitudinal direction.

The invention may be embodied in a one-piece blow moulded container as shown in figure 10. For many products, milk for example, the opening of the closure can be made quite large to permit very high filling rates. The closure merely has to be snap shut (and heat sealed or otherwise bonded if required) and this obviates the need to store and handle separate screw or snap-on closures. Note that in figures 1,2,8,9, and 12, a tab 27 is attached to the flexible section to facilitate opening; this may be quite large so that disabled persons may more easily use the closure. The tab may protrude as in figures 1,2,8,9, and 12 so that one hand may be used to open the closure. Alternatively, the flexible panel may overhang the fixed part of the closure in the closed position, as in figure 10, so that it may be opened by applying pressure to the overhanging edge.

It may be required to incorporate the device of the invention into a screw top or snap-on cap, so that existing containers may be used, and such an embodiment is illustrated in figure 11.

Many closures are required to be child resistant, for example closures for pharmaceutical tablet containers, and figures 12a to 12e show one of many methods which may be used to render the device of the invention child resistant. In this example like parts are given like numbers for simplicity. The basic closure 28 is fitted with a cap 38, retained by co-operating projections 33. The cap is shown in figures 12a and 12b in the ready to open position, with a finger groove 31 in line with tab 27 on flexible section 32. Referring to figure 12c, the cap is shown in its unoperated position; the opening tab 27 and flexible section 32 are covered by the cap, and the closure cannot be opened. The cap 30 is free to rotate on closure 28, and is biassed by a spring 34, said spring being attached at end 35 to the closure 28.The free end 36 of spring 34 cooperates with a projection 37 on cap 30, so as to rotationally bias the cap against the direction of arrow X. To operate the closure, a finger or thumb is placed in the finger groove 31, with the tip of the digit facing the cut-out 40 in cap 30.

Alternatively, the rim of the cap 30 may be gripped between thumb and the second finger, with the index finger in the finger groove 31, and facing the cut-out 40. By twisting the cap in the direction of arrow X, the cut-out 40 may be brought into line with the flexible panel 32 and tab 27, as shown in figure 12d. The index finger is now pushed forward in the direction of the cut-out 40 in cap 30, so as to push on the tab 27 and thus open the flexible section 32, as shown in figure 12e. One or more projections 39 on flexible section 32 engages with the edge of cut-out 40 or an abutment fixed thereto, and prevents the spring-biassed cap from returning to the position depicted in figure 12c. The contents may now be dispensed from the container.To close the container, the tab 27 and/or flexible section 32 is pressed by a finger towards the centre of the cap 30, and snaps back into the closed position; when the finger is withdrawn, the cap 30, which is no longer held by projection 39, returns by the action of spring 34 to the closed position shown in figure 12c.

A beneficial feature arising from the examples described is that the edge of the thin section is curved - necessary for the edge to mate with the co-operating surface when in the closed position: when in the open position, the curved edge acts as a pouring lip.

The preferred material of manufacture is a plastic, such as polypropylene or polyethyltetrapthalate (PET), since these materials have the optimum blend of properties, but of course metals or cardboard (including coated and laminated boards) may be used if the application so justifies.

The curved surfaces of the cross section of various embodiments may be curved in more than one plane, or be substituted by flat surfaces, suitably hinged, whist still achieving the main objective of the present invention.

All features described herein which are not mutually exclusive may be combined in any combination to achieve the object of the invention, and devices and methods which achieve the same result as those devices and methods described are deemed to be part of this specification.

Claims (18)

1. A closure comprising a flexible panel attached by one or more hinges to the wall of a container or cap for a container, the line of action of the hinge defining an opening in the wall through which the flexible panel may pass when pressure is applied to said panel, and which opening is smaller than the panel. In the closed position, the flexible panel substantially contacts a co-operating surface on the container or container cap, to create at least a partial restriction of the opening in the container or container cap.

2. A closure as in claim 1 in which the flexible panel is provided with grooves or ribs to enhance rigidity in the longitudinal direction whilst maintaining flexibility in the circumferential direction.

3. A closure as in claims 1 and 2 in which the flexible panel is curved in the open or closed condition.

4, A closure as in claims 2 and 3 in which the grooves or ribs are evenly spaced.

5. A closure as in claims 2 and 3 in which the grooves or ribs have a varying pitch.

6. A closure as in any claim 1 to 5 wherein means is provided to seal the closure to a substantially liquid-tight condition.

7. A closure as in claim 6 whereby the seal is effected by a heating process.

8. A closure as in claim 6 whereby the seal is effected by mechanical crimping.

9. A closure as in claims 1 to 8 in which the hinge is an integral part of the closure.

10. A closure as in any preceding claim in which the thickness of the flexible panel varies.

11. A closure as in any preceding claim which has a tag fitted to or integral with the flexible panel to assist operation of the closure.

12. A closure as in any preceding claim which is fitted with a tamper evidence device.

13. A closure as in any preceding claim which is fitted with a child resistant device.

14. A closure as in any preceding claim which is manufactured from polypropylene.

15. A closure as in claims 1 to 13 which is manufactured from plastic.

16. A closure as in claims 1 to 13 which is manufactured from metal.

17. A closure as in claims 1 to 13 which is manufactured from cardboard or paper, or a composite of paper and plastic, or a composite of paper, plastic and metal foil.

18. A closure as in any preceding claim which is manufactured as an integral part of a container.