Bottles and jars – Closures – With separate applied fastener to hold closure in closed...
Reexamination Certificate
1999-07-12
2001-04-24
Cronin, Stephen K. (Department: 3727)
Bottles and jars
Closures
With separate applied fastener to hold closure in closed...
C215S347000, C215S349000, C215S350000
Reexamination Certificate
active
06220466
ABSTRACT:
This invention relates to composite closures for packaging containers, that is to say, closures having a sealing disc arranged as an insert to overlie and seal with the mouth-defining rim of the container, and an open-ended, tubular plastics band in which the disc is fitted and retained. The invention also extends to the insert discs for such closures. The band of such a closure is formed internally with one or more thread or snap-engagement formations which are capable of engaging with a complementary formation or formations on the container to attach the closure and the container together.
For some packaging applications composite closures have various advantages over conventional closures (i.e. those having non-apertured crowns), and they are widely used for food products which either are filled hot or are pasteurised or sterilised in the container.
A form of composite closure is known from European patent specification No. 0272431B1 (Agents ref. 4386), in which the insert disc is cut and stamped-from a multi-layer extruded plastics material so as to have a circular inner portion surrounded by a generally C-shaped outer portion. When the closure has been fitted to a container the outer portion of the insert disc forms a downwardly facing annular channel by which the container rim is received in sealing relation, the inner portion then overlying and closing the container mouth.
A shortcoming of the closure described in EP.0272431 and recited above arises because of the presence of the generally C-shaped outer portion of the insert disc. For enabling the disc to achieve a satisfactory seal security with the container, heat and pressure is used in order to give the disc a required, closely toleranced shade around its margin. The present invention stems from the realisation by the Applicants that substantial cost savings and other benefits may be achieved by use of a planar, at least substantially plastics, sheet, multilayer or otherwise, which is capable of adopting (and adopts) a required non-planar configuration in the fitted closure.
Another composite closure having a plastics or substantially plastics insert disc is shown in U.S. Pat. No. 4,782,968. The disc may be cut from a plane plastics sheet, with the accompanying cost advantages over discs which have a non-planar configuration by use of an appropriate manufacturing method, e.g. by thermoforming. However, in U.S. Pat. No. 4,782,968 the assembly of the closure requires the disc to be secured peripherally to the tubular band of the closure. The securing operation, which is achieved by spin-welding, induction-sealing or mechanical clinching, is an added cost of manufacture. Moreover the attachment of the disc to the band will restrict the ability of the disc to conform itself to the container finish with which it is required to seal, and may limit the applications for which the closure may be used because of the need to avoid excessive stresses at the interconnection made between the two components.
It is also known for conventional plastics closures to provide a disc-like sealing liner of such a size that when the closure is fitted to a container neck it will project outwardly beyond the container rim as an overhanging peripheral margin, and for the closure to have a formation around the underside of its crown and arranged to bear downwardly on the overhanging margin when the closure is fitted, so as by abutment to wrap the margin around the outside radius of the container rim. In this way the security of the seal provided by the liner is enhanced and made less sensitive to top loading of the closure in storage, transit and display. A closure of this kind is featured in European Patent Publication EP 0693434A.
From the foregoing it might accordingly be expected that the combination of an inherently plane insert disc with a closure shell which has an abutment formation arranged to engage an outer peripheral margin of the disc so as to wrap it in close sealing relation around the container finish could provide a composite closure with a desirable combination of relatively low cost and good sealing integrity. However, a wholly or substantially plastics composition for the insert disc and band, together with any elevated temperatures and/or differential pressures to which the closure might be subjected during use and when further allied with an increased ability of the closure to deform because of the weakening effect of the opening in the band above the insert disc, in practice make the achievement of good sealing integrity difficult to achieve reliably.
Failures in seal integrity may have their origin when the disc is being assembled with the band in the initial creation of the closure, and/or they may be caused by the forces which are imposed on the band and the disc during a capping operation to fit the closure subsequently onto a container. Whatever their origin, Applicants have discovered that the sealing failures can be substantially reduced if in the assembled closures the discs are subjected to radially inward compressive forces, and, moreover, doming of the discs resulting from these forces is directed outwardly of the closure, that is, towards the adjacent opening in the band, which is available to accommodate the doming at least partially.
In accordance with the invention from a first aspect there is accordingly provided a composite closure for a container prior to fitting to the same, which comprises a substantially open-ended, tubular plastics band internally formed with one or more thread or snap-engagement formations for engagement with a complementary formation or formations on the container to attach the closure to the container, and a captive insert disc at least substantially of plastics material which is fitted and retained in the band for overlying and sealing with the mouth-defining rim of the container, characterised in that:
a) the disc has its free edge received in an inwardly facing annular recess adjacent an inwardly extending flange formation which forms an opening at one end of the band;
b) the disc is oversized radially in relation to the recess and by engagement of the free edge with the outer periphery of the recess is held in a domed condition which is convex to the closure exterior and projects towards the opening of the band; and
c) the band includes abutment means by which, when the closure has been fitted to the container, a marginal region of the disc including the free edge may be deformed downwardly around the container rim.
In accordance with a second aspect the invention provides a method of assembling the band and the disc in the manufacture of the composite closure defined in the previous paragraph, characterised in that the disc is forced into position within the recess, past the thread or snap-engagement formation(s), by engagement of a pushing means with a central region of the disc, the disc being thereby caused to adopt the said convexly domed condition which is subsequently maintained by engagement with the outer periphery of the recess.
From yet a third aspect the invention provides a container closed by a composite closure as defined in the penultimate paragraph and preferably as assembled by the method defined in the preceding paragraph, characterised in that by virtue of its engagement by the abutment means the marginal region is deformed to a downwardly extending, generally frustoconical position.
From a fourth aspect the invention provides a method of forming the closed container defined in the preceding paragraph.
REFERENCES:
patent: 4171084 (1979-10-01), Smith
patent: 4408694 (1983-10-01), Mueller
patent: 4418834 (1983-12-01), Helms et al.
patent: 4452842 (1984-06-01), Borges et al.
patent: 4462502 (1984-07-01), Luenser et al.
patent: 4501371 (1985-02-01), Smalley
patent: 4705183 (1987-11-01), Moloney
patent: 4733786 (1988-03-01), Emslander
patent: 4757914 (1988-07-01), Roth et al.
patent: 4782968 (1988-11-01), Hayes
patent: 4993572 (1991-02-01), Ochs
patent: 5009324 (1991-04-01), Ochs
patent: 5031787 (1991-07-01), Ochs
patent: 5062538 (1991-11-01), Ochs
patent:
Hayes Thomas H
Saunders Cyril Hadyn
CarnaudMetalbox (Holdings) USA Inc.
Cronin Stephen K.
Wood Herron & Evans L.L.P.
LandOfFree
Composite closure, method for assembling it and method for... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Composite closure, method for assembling it and method for..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Composite closure, method for assembling it and method for... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2504526