Vented composite closure

Details Vented composite closure Vented composite closure

1999-05-19

2001-08-21

Cronin, Stephen K (Department: 3727)

Bottles and jars

Closures

Frangible member or portion

C215S276000, C215S350000

Reexamination Certificate

active

06276543

ABSTRACT:

FIELD OF THE INVENTION
This invention relates to a closure for sealing a food container, and more particularly, to a closure having vents to provide air communication to an internal portion thereof.
BACKGROUND OF THE INVENTION
Composite closures are widely used to seal food containers, for example wide mouth containers that are “retorted” after sealing. Such closures comprise a sealing disk or cover, usually of metal or alternatively plastic, which is encircled and housed within a separately formed molded plastic band or shell. The disk has a raised peripheral crown that presents a downwardly opening groove that contains a sealant or gasket for forming a seal with a sealing rim around the top or finish of the container. The shell holds the disk down on the container but is rotatable relative to the disk so as not to turn the disk on the container, which would greatly increase the torque required for opening or closing. This type of seal is relatively insensitive to the thermal expansion and contraction that occur during retorting. (In retorting, after the container has been filled it is heated to a temperature above about 220 degrees F. under external pressure to sterilize the food sealed in it.)
U.S. Pat. No. 4,813,561, which is incorporated herein in its entirety, shows a composite retortable closure having a metal disk with a raised peripheral bead. The bead presents a downwardly opening groove that contains a sealant or gasket material for making a seal with the top, outer, and/or inward surface of the rim of the container. The disk is rotatably housed within an encircling molded plastic shell having an inwardly projecting curved lip that extends to and engages the top of the bead of the disk. As the shell is tightened, the undersurface of the lip bears downwardly on the disk bead thereby forcing the sealant material into sealing engagement with the container rim. The '561 patent also describes a tamper indicating band around the lower edge of the shell. The band is connected to the shell by a line of weakness provided by a series of small frangible bridges, and includes an upwardly and inwardly projecting band retainer. Interengaging ratchet teeth are provided on the container and the inwardly facing surface of the retainer. When the closure is first opened, the interengaging ratchet teeth prevent the retainer from turning with the rest of the closure, which in turn causes the tamper evidencing band to break off along the line of weakness. The band then drops downwardly, thereby indicating at least partial opening.
U.S. Pat. No. 5,346,082, which is incorporated herein in its entirety, discloses a composite closure for a container. The closure has an outer shell with a half-toroidal lip that overhangs a bead around the periphery of an insert cover disk. As the closure is tightened on the container, the lip bears downwardly on the crown of the disk and urges the disk against the container rim. Reaction force uncoils the hook like a watch spring, and a visible gap develops between the inner edge of the lip and the disk. This gap provides a visible on-line indicator that the hook is exerting sealing force on the disk. The '082 patent also discloses an improved tamper evident band.
The '082 patent discloses channels for enabling water to drain or dry from the interthread space around the threads of the container and closure. The '082 patent disclosed a closure having a movable gap between the edge of the lip and the disk, and channels to promote draining and drying. The gap unwinds in response to tightening of the closure onto the container. It is a goal of the present invention to provide a composite retortable closure that has improved draining and drying characteristics.
SUMMARY OF THE INVENTION
A retortable closure package is provided that comprises a container and a closure. The container has a securement member formed thereon, which preferably is a single continuous thread. According to the present invention, the closure includes a metal disk and a molded plastic band. The disk has a center portion and an annular raised crown disposed around the center portion. The crown has a groove formed on an underside thereof that contains a gasket engageable with a rim of the container. The band has an inwardly extending semi-toroidal annular hook and a skirt extending downward from the hook. The skirt has a securement member, which preferably is a single continuous thread, which is engageable with the securement member on the container. The hook has a lower edge opposite the skirt that is spaced apart from the disk.
According to an aspect of the present invention, an underside of the hook includes pads, vents, and an annular recess. The plurality of pads urges downward against the crown (preferably at the apex of the crown) exerting downward force on the crown and not exerting radial clamping force across the crown in response to coupling together the closure and the container. An annular recess is formed in the underside of the hook and defines an end of the pads. The plurality of vents is disposed between the pads, and an end of the vents is defined by the annular recess, whereby the vents provide communication between the securement members and the environment to enable evaporation of liquids disposed within the closure.
The closure according to the present invention preferably includes an annular retaining bead inwardly projecting from the skirt. The retaining bead holds the disk while the closure is uncoupled from the container. When the closure is applied, the container urges upward against the disk to provide space between the retaining bead and an edge of the disk, thereby enabling communication between the vents and the securement members.
The hook underside has an outboard portion defined by the annular recess and the retaining bead, and the outboard lower portion is spaced apart from the crown to enable communication between the vents and the securement members. Preferably, the vents are coextensive with the hook from the disk edge to the annular recess and have a substantially uniform thickness. The pads also have substantially uniform thickness. The lower portion of the hook above a retaining bead lacks vents, and is spaced apart from an outside wall of the crown. The package further has a tamper evident band that includes ratchets that restrict opening of said closure.


REFERENCES:
patent: 4809858 (1989-03-01), Ochs
patent: 4813561 (1989-03-01), Ochs
patent: 4880127 (1989-11-01), Doi
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: 5078290 (1992-01-01), Ochs
patent: 5346082 (1994-09-01), Ochs et al.
patent: WO 91 03404 (1991-03-01), None
patent: WO 92 03370 (1992-03-01), None

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