EP1732818B1

EP1732818B1 - Fitting caps to containers

Info

Publication number: EP1732818B1
Application number: EP05718100A
Authority: EP
Inventors: Matthew Eric Smith; Karl Mondszein
Original assignee: Carbonite Corp
Current assignee: Carbonite Corp
Priority date: 2004-03-25
Filing date: 2005-03-23
Publication date: 2008-04-30
Anticipated expiration: 2025-03-23
Also published as: PL1732818T3; DE602005006402D1; EP1732818A1; ES2304694T3; WO2005092730A1; DE602005006402T2; ATE393736T1; GB0406764D0

Abstract

The invention relates to a method of snap-fitting a lid to a container (2) including a neck (8), which defines the mouth of the container and on whose outer surface there is a downwardly directed shoulder (14). The lid also includes a closure plate (30, 32) connected to a depending peripheral skirt (18), connected to which by a resilient hinge (22) is a retaining flange (20). The method includes moving the lid and container relatively towards one another to bring the retaining flange (20) into contact with the upper edge of the neck (8), thereby causing the retaining flange (20) to rotate about the hinge (22) until the free end of the flange (20) moves past the shoulder (14). The retaining flange (20) is then rotated in the opposition direction towards the neck (8) of the container by the resilience of the hinge and engages beneath the shoulder (14), thereby restraining relative movement of the lid and receptacle away from one another. The side surface of the free end of the retaining flange (20) is urged into sealing engagement with the outer surface of the neck (8) by the resilience of the hinge (22) and the free end of the retaining flange (20) is drawn into sealing engagement with the shoulder (14) by the tensional stress in the skirt (18) caused by deformation of the cap engaging the upper surface of the rim (8).

Description

The present invention relates to containers, e.g. for beverages, particularly carbonated beverages, foodstuffs or cosmetics and is concerned in particular with such containers with wide mouths, that is to say with a diameter in excess of about 25mm, preferably about 38mm, more particularly 45mm. More specifically, the invention is concerned with a method of fitting caps to such containers.
Beverage bottles typically have a narrow mouth with a diameter in the region of only 28mm or less. Numerous ways of sealing the bottle top to the neck of the bottle are known but it will be appreciated that the problem of producing a seal on a container for a carbonated beverage increases exponentially as the diameter of the mouth increases because the area of the underside of the cap or top increases in accordance with the square of the radius. If the container cap or its seal should fail, the gas pressure will be released and the cap may even be projected explosively into the air with the resultant loss of the beverage and potential injury to bystanders. Similar sealing problems can arise also with uncarbonated beverages because if the container is subjected to an elevated temperature, e.g. it is exposed to direct sunlight, the gas pressure in the head space of the container will increase and if the container is inadequately sealed this will result in the leakage of gas to the atmosphere. This is not of itself inherently problematic, but when the container cools again, a subatmospheric pressure may be produced in the head space which results in the induction of atmospheric oxygen. This can result in oxidation of the container contents rendering them undrinkable.
Rotatable retaining flanges are disclosed in the documents WO-A- 01/08991 , US-A- 5443853 and FR-A-2 377 333 .
The use of wide mouthed beverage containers is rapidly becoming more widespread and it is the object of the invention to provide a method of fitting a lid to such a container which will form a reliable seal which can contain the pressure generated by a carbonated beverage or generated under high ambient temperature conditions in the head space of a container containing an uncarbonated beverage or foodstuff but which can nevertheless be rapidly and simply removed, when required. It is further desirable that the method should be cheap, simple and rapid.
According to the present invention, a method of snap-fitting a lid to a container including a neck, which defines the mouth of the container and on whose outer surface there is a downwardly directed shoulder, the lid including a closure plate connected to a depending peripheral skirt, connected to which by a resilient connection is a retaining flange, includes moving the lid and container relatively towards one another to bring the retaining flange into contact with the upper edge of the neck, thereby causing the retaining flange to rotate about its resilient connection until the free end of the retaining flange moves past the shoulder, whereafter the retaining flange is moved towards the neck of the container by the resilience of the connection and engages beneath the shoulder, thereby restraining relative movement of the lid and receptacle away from one another.
Thus the internal diameter of the retaining flange, before the cap is fitted to the container, is less than the external diameter of at least a portion of the rim of the container. This means that as the cap and the container are moved towards one another, the retaining flange comes into contact with the external surface of the rim and this causes the flange to rotate slightly in one direction about its resilient connection to the peripheral skirt. The resilience of the connection means that a restoring force is applied to the flange tending to cause it to return to its original position. As soon as the free end of the flange, which is preferably elongate in axial sectional view, moves past the downwardly directed shoulder, the restoring force causes the flange to rotate in the other direction, whereby the free end of the flange is engaged beneath the shoulder. This engagement will prevent the cap from being removed from the bottle without at least partial rupturing or destruction of the cap.
In the preferred embodiment, the resilient connection is such that it presses the side surface of the flange into sealing contact with the outer surface of the neck of the container. According to the invention the closure plate is connected to the peripheral skirt by an integral annular web and the method includes applying sufficient force to the cap that the underside of the annular web is compressed by contact with the rim of the container, whereafter the retaining flange is moved towards the neck of the container, whereby when the force is removed the compression of the web draws the retaining flange upwardly such that its free end is drawn by the tensional stress induced in the skirt into sealing contact with the shoulder.
Thus the cap is simply snap-fitted to the container and all that is needed is to move the cap and the container towards one another in the direction parallel to the container with a force sufficient to rotate the retaining flange sufficiently that it can pass over the neck of the bottle and preferably also with a force sufficient to deform the annular web connecting the peripheral skirt to the closure plate. In practice, this will mean that the distance between the upper surface of the rim of the container and the downwardly directed shoulder is slightly less than the distance between the underside of the annular web and the free end of the retaining flange, when rotated into the position in which it extends generally parallel to the axis of the container, which is the position it occupies when the cap has been fitted to the container.
Further features and details of the invention will be apparent from the following description of one specific embodiment which is given by way of example only with reference to the accompanying diagrammatic drawings, in which:

Figure 1 is a vertical sectional view of a beverage bottle in accordance with the invention with the lid in an intermediate position whilst being applied to the bottle;
Figure 2 is a vertical sectional view of the container lid before application to the bottle;
Figure 3 is a scrap sectional view of the upper portion of the bottle showing the lid in the applied and sealed position;
Figure 4 is a side view of the upper portion of the bottle as seen in Figure 3; and
Figure 5 is a scrap view from below of part of the lid showing the rupturing tab.

As seen in Figure 1, the bottle 2 is of generally cylindrical shape with an axis 3 and at least one portion 4 of increased size whose diameter is greater than that of the lid 6, for reasons which will be explained below. The bottle is in this case moulded from plastic material and it has a wide mouth, with a diameter of greater than 28mm defined by the neck 8 of the bottle. The neck 8 terminates at a rim portion which is defined by an internal surface 10, which constitutes a sealing surface and is inclined upwardly and outwardly with respect to the axis 3, and an external surface 12, which is inclined upwardly and inwardly with respect to the axis 3. The surfaces 10 and 12 thus converge and the external diameter of the bottle, specifically of its rim portion, thus initially increases from the top downwards. However, it then decreases abruptly at a downwardly directed annular shoulder 14 extending substantially perpendicular to the axis 3. The internal diameter of the rim portion, however, initially decreases from the top downwards.
As best seen in Figure 2, the lid comprises a one-piece component, preferably integrally moulded from plastic material, such as polypropylene. It comprises a shaped closure plate integral with which is a web 16 which extends, when the lid is connected to the bottle, over the rim of the bottle. Integral with the web 16 is a depending skirt 18, which extends downwardly around the exterior of the upper portion of the bottle. Integrally connected to the lower edge of the skirt 18 or to the inner surface of the skirt at a position adjacent its lower edge is an annular retaining flange 20, which is elongate in axial section. The flange 20 is connected to the skirt 18 by a resilient connecting web 22, which is of reduced thickness and thus constitutes an annular line of weakness or predetermined breaking point. Connected to the lid at one circumferential position is a rupturing tab 24 which extends downwardly below the lower edge of the skirt 18. This tab is connected to the skirt 18 at its side by two lines of weakness 26, i.e. regions of reduced thickness.
The closure plate of the lid is concave and thus extends into the neck of the bottle, when it is connected to the bottle. The closure plate comprises a wall portion 30 which extends generally downwardly and inwardly and merges at its lower edge with a base portion 32, which is downwardly arcuate, that is to say is of downwardly curved convex shape. The wall portion 30 is in fact slightly arcuate and its outer surface constitutes a sealing surface 34.
The lid is shown in Figure 2 in the configuration in which it is moulded. In this configuration, the flange 20 extends downwardly and inwardly and the diameter of its lower edge is less than that of the upper edge of the rim of the bottle whilst the diameter of its upper edge is greater than that of the upper edge of the rim of the bottle.
The lid is fastened and sealed to the bottle by a simple snap-fit procedure. This is effected simply by lowering the lid into the rim of the bottle and then applying pressure. As the lid is lowered, the lower edge of the flange 20 comes into contact with the rim. This causes the flange to rotate inwardly about the web 22. As downward movement of the lid continues, the flange 20 moves downwardly in contact with the surface 12, as shown in Figure 1, and the increasing diameter of this surface in the downward direction results in the rotation of the flange continuing, thus moving it ever closer to the inner surface of the skirt 18. The lower surface of the web 16 then comes into contact with the upper surface of the rim of the bottle and the continued application of pressure results in slight compression of the material of the web 16. The free end of the flange 20 then moves past the shoulder 14 and it is rotated in the opposition direction, i.e. inwardly, by the resilience of the web 22 and thus becomes locked behind the shoulder, as shown in Figure 3. The lid is now retained in position on the bottle and cannot be removed without damaging or deforming it. The resilience of the web 22 forces the side surface of the free end of the web 22 into contact with the outer surface of the bottle and thus forms a gas seal. When the force on the cap is removed, the compression of the web 16 draws the flange 20 upwardly so that its free end is drawn by the tensional stress in the skirt 18 into sealing contact with the shoulder 14. The upper edge of the rim firmly engages the underside of the web 16 and this not only prevents further downward movement of the lid relative to the bottle but also constitutes a further gas seal. The integrity of this may be further enhanced, if required, by the provision of an annular bead or flange 17, which is shown in phantom lines in Figure 2 and which will engage the upper or side surface of the rim of the bottle and constitute an additional lip seal. The two sealing surfaces 10 and 34 are also in contact and this contacting region constitutes yet a further gas seal of the bottle. If the pressure in the bottle should become superatmospheric, either as a result of the liberation of carbon dioxide from a carbonated beverage or as a result of expansion of gas in the head space of the bottle due to an increase in temperature, the centre of the concave base portion 32 will be deformed upwardly and this will inherently result in the outer edge of the base portion 32 and thus the lower edge of the wall portion 30 moving slightly outwards. This will result in an increase in the contact pressure between the sealing surfaces 12 and 34 and thus in an enhancement to the integrity of the primary gas seal. The beverage container thus has a total of four gas seals, the integrity or sealing ability of at least some of which increases as the gas pressure within the container increases.
When it is desired to open the bottle, the user merely grasps the lower edge of the rupture tab 24 and pulls it outwardly. The lines of weakness 26 immediately rupture or stretch and the upper edge of the tab 24, which is connected to the web 16 rotates. This rotation is transmitted to the web 16, which thus moves away from the rim of the bottle, thus breaking the gas seal between the web 16 and the rim of the bottle. This movement of the web 16 also causes the sealing surfaces 12 and 34 locally to move apart, thereby also the gas seal between them. The two seals formed by the flange 20 are also broken. The container is thus depressurised. The outward movement of the tab 24 initiates tearing of the thin connecting web 22, and once tearing has started it is a simple matter to keep it going by exerting upward and outward pressure on the tab 24 until the lid is completely disconnected from the flange 20, which remains in position around the neck of the bottle. The lid may now be discarded and the contents of the bottle dispensed or drunk.
As mentioned above, the body of the bottle has one or more protuberances 4 whose contour extends beyond that of the lid, when viewed in the axial direction. This means that when a number of such bottles are packaged together side by side, they will contact one another only at the protuberances and the lids of adjacent bottles will not contact one another, thereby eliminating the risk that the lids may inadvertently become dislodged, thereby venting the interior of the associated containers. The base of the bottle also has a shape which is complementary to that of the upper surface of the lid so that bottles may be simply and securely stacked on top of one another.
Although the container of the present invention is intended primarily for beverages, i.e. for liquids that are intended to be drunk, it will be appreciated that it will be equally applicable to other flowable foodstuffs or other materials, such as cosmetics.

Claims

A method of snap-fitting a lid (6) to a container (2) including a neck (8), which defines the mouth of the container and on whose outer surface there is a downwardly directed shoulder, the lid (6) including a closure plate connected by an integral annular web (16) to a depending peripheral skirt (18), connected to which by a resilient connection (22) is an annular retaining flange (20) which is elongate in axial cross-section, the method including moving the lid and container relatively towards one another to bring the retaining flange into contact with the upper edge of the neck (8), thereby causing the retaining flange (20) to rotate about its resilient connection (22) until the closure plate comes into contact with the upper surface of the neck, applying sufficient force to the cap that the underside of the annular web (16) is compressed by contact with the rim of the container until the free end of the retaining flange moves past the shoulder, whereafter the retaining flange (20) is moved towards the neck of the container by the resilience of the connection and its free end engages beneath the shoulder and removing the force from the cap whereupon the compression of the web draws the retaining flange upwardly so that its free end is drawn by the tensional stress induced in the skirt into sealing contact with the shoulder, thereby restraining relative movement of the lid (6) and the receptacle (2) away from one another.
A method as claimed in Claim 1 in which the side surface of the retaining flange is pressed against the outer surface of the neck of the container by the resilience of the resilient connection with sufficient force to form a seal.