Closure for containers

Abstract

A closure for a container having a rim surrounding an opening to be closed, the closure including a lid portion having a peripheral rim portion adapted to sealingly engage the rim of the container, and a peripheral ring portion extending from the rim portion of the lid portion and having a depending portion adapted to engage the rim of the container to hold the peripheral rim portion in sealing engagement with the container rim. The depending portion is formed with a multiplicity of separate flexible finger elements, each having an inwardly directed abutment portion which in use engages the rim of the container to hold the closure in the closed position, the fingers occupying in their as molded or neutral positions a position in which the abutment portions are in use at least partially engaged with the rim of the container.

Description

FIELD OF THE INVENTION [0001] This invention relates to closures for containers, and more particularly to closures for larger containers, such as larger volume paint cans. The invention is not restricted to such applications and is equally applicable to all containers including containers of small volume. BACKGROUND OF THE INVENTION [0002] Containers for larger volumes of paint are usually closed by a metal lid which sealingly engages the curl of the container and which is held in its closed position by a metal locking ring. Such locking rings are relatively expensive and are difficult to fit using standard can filling and scaling machines. [0003] Plastic closures are easier to fit using such machines but are difficult to seal properly under all conditions, and are not sufficiently strong to allow stacking for storage and-transport. [0004] Composite plastic / metal closures which overcome the above problems are to be found in the patent literature such as: [0005] U.S. Pat. No. 3,930,5...

AI Technical Summary

Benefits of technology

[0010] It will be appreciated from the above that closures embodying the invention are able to be easily fitted to a container when the locking ring is in the open position, or as described below, with the locking ring in the closed position, while the locking ring provides sealing security for the closure, along the lines of the known metal locking ring, when the locking ring is in the closed position. By arranging the fingers in the locking position in their neutral state, the problems associated with fingers which are hinged outwardly are avoided.

[0015] The division of the skirt into separate fingers allows the fingers to be moulded with a deeper locking undercut than would be possible with a integral skirt. The separate fingers allow the deep locking undercut to be more easily demoulded.

[0017] Each of the finger elements may be formed with an outwardly projecting flange or stop member which defines the closed position of the locking ring, preventing the locking ring moving downwardly any further than the flange or stop member.

[0018] The locking ring flange or stop member is preferably formed with a downwardly projecting extension preferably strengthened by an inwardly projecting web which is shaped to assist in guiding the closure into engagement with a container during the closure applying process.

[0021] As mentioned above, while the composite closure defined above has particular application to containers or cans of larger volumes which require a stronger lid portion, the closure also may offer advantages in other applications in which the closure may be formed as a unitary moulding of the same plastic material. A closure formed as a unitary moulding may have application in relation to containers for dangerous goods in which sealing integrity is important.

Problems solved by technology

Such locking rings are relatively expensive and are difficult to fit using standard can filling and scaling machines.

Plastic closures are easier to fit using such machines but are difficult to seal properly under all conditions, and are not sufficiently strong to allow stacking for storage and-transport.

While this closure is described as a pry-off closure, requiring the use of a tool to open the closure, this is primarily because the closure as illustrated is for small containers such as food jars which do not allow the user's fingers to manipulate the skirt to remove the closure.

While this closure similarly addresses the issue of automated fitting and manual removal, it may still be difficult to easily manually remove the closure due to the requirement that the skirt of the plastic ring must be sufficiently rigid to ensure that engagement of the skirt with the curl of the container maintains a proper seal between the lid and the rim of the container.

A problem with such arrangements is that the fingers tend to force the locking ring upwardly and stretch the locking ring due to the outward flex load of the outwardly hinged fingers.

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