Receptacles – Closures – With closure opening arrangements for means
Patent
1997-11-05
1999-09-21
Cronin, Stephen K.
Receptacles
Closures
With closure opening arrangements for means
215253, B65D 1740
Patent
active
059542209
DESCRIPTION:
BRIEF SUMMARY
The present invention relates to a closure retention system for containers and has particular application to dangerous goods containers having snap-on, as distinct from screw threaded, closures. For many years dangerous goods have been supplied in open head metal buckets with metal lids; a seal being effected adjacent the upper extremity of the bucket where it lies against the lid.
International regulations concerning dangerous goods containers have now been devised whereby such containers must withstand certain defined tests such as drop, stack and pressure tests without rupture of a seal.
Various thermoplastic container/closure combinations have been devised usually with single retainers although such containers have consistently failed to pass the stringent United Nations (UN) Dangerous Goods Code. The principal difficulty associated with thermoplastic closures of the type which utilise a ring incorporated in the closure skirt to override and then underlie an outwardly directed protuberance on the pail is that once the ring has passed over the protuberance on the pail and lies in its closed position beneath such protuberance it is still subject to stress which eventually causes the thermoplastic material from which the ring is fabricated to creep radially outward hence degrading the seal between such ring and the outwardly directed protrusion on the container. Elaborate systems for such "snap-on" thermoplastic closures have been devised involving multiple retainers co-operating with multiple protrusions on containers but to date most such closures still fail to pass the UN Group 2 Liquid Dangerous Goods Code.
It is accordingly an object of the present invention to provide a thermoplastic closure for a dangerous goods or high performance bucket; the seal of such closure adapted to withstand substantial impacts which may be inflicted on the container/closure unit.
According to the present invention there is provided a thermoplastic closure for an open headed container adapted to effect an impact resistant seal with such a container; the closure being comprised of a circular disk portion and a peripheral skirt portion; the skirt portion including a thickened portion adapted to lie beneath and radially inward with respect to an outwardly directed annular protrusion on a complimentary container; a weakened stress relieving annular portion on the skirt lying immediately above said annular thickened portion; the annular weakened portion having a wall thickness at least twenty percent less than that of the annular thickened portion of the skirt although of adequate thickness to resist premature rupture in the event that the closure/container unit is subject to an impact; seal means between the closure and the container above the annular thickened portion.
Three embodiments of the present invention will now be described with reference to the accompanying drawings in which:
FIG. I is a partial sectional view through a steel container/thermoplastic closure intersection in accordance with the present invention;
FIG. II is a partial sectional view through a thermoplastic container/thermoplastic closure intersection in accordance with the present invention before initial sealing of the closure to the container; and
FIG. III is a partial sectional view of the thermoplastic container/thermoplastic closure of FIG. II after initial sealing of the container.
With reference to FIG. I there is disclosed, in section, the upper portion of a steel dangerous goods bucket 1; the extreme upper extremity of the bucket being rolled so as to form an outwardly directed protrusion 2 of substantially constant radius. The closure of FIG. I comprises a disk portion 3 extending via radiused portion 4 into skirt portion 5. In this example internal skirt 6 additionally assists to locate the closure with respect to the container.
The skirt portion 5 is comprised of a relatively thick walled upper section 17 extending into radiused portion 4 with a relatively thin walled stress-relieving annular portion 7 therebeneath lying adjacent outwardly
REFERENCES:
patent: 3831798 (1974-08-01), Rowe et al.
patent: 5511679 (1996-04-01), Beck
Cronin Stephen K.
Quinton James A.
LandOfFree
Dangerous goods closure system does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Dangerous goods closure system, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Dangerous goods closure system will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-72698