Bottles and jars – Closures – Frangible member or portion
Patent
1989-03-22
1991-01-15
Marcus, Stephen
Bottles and jars
Closures
Frangible member or portion
215258, B65D 4134
Patent
active
049847015
DESCRIPTION:
BRIEF SUMMARY
The present invention relates to a tamper-evident closure for use in connection with a rigid container including a threaded neck portion and an annular rib below said threaded neck portion, said closure comprising a one piece plastic capsule including a flat top wall and a cylindrical skirt, the inner surface of said flat top wall including sealing means cooperating with the upper end of the container neck portion and said cylindrical skirt including an internally threaded upper portion, an intermediate portion comprised between two circumferential weakening zones, said intermediate portion forming a tearable opening band having a gripping portion, and a lower portion including an inwardly projecting annular engagement rib which snap engages below said annular rib of the container neck as a result of the first screwing on of the capsule.
A tamper-evident closure of the above mentioned type is known from FR-A-92382. Said document describes a capsule made of polyethylene; in the capsule illustrated in FIG. 7 of said document the entire tearing band extends outwardly of the skirt of the capsule relative to the two weakened zones which connect the tearing band to the skirt of the capsule.
The capsule disclosed in FR-A-92382 could not be used as closure for rigid containers, generally of glass, which are used in the food industry for containing products which are subjected, after the container has been filled and closed, to a heat treatment at a relatively high temperature to pasteurize the product or create a vacuum within the container, in order to ensure preservation of the product in time.
In fact, in order to ensure the necessary resistance to the heat treatment, the capsule should be made of a plastic material having a hardness much greater than that of polyethylene; the Applicant has found that if a very rigid plastics material, such as polypropylene filled with mineral fibre having a hardness greater than 75 Shore D, is used for the manufacture of a capsule as disclosed in FR-A-92382, the tearing band is broken prior to the completion of the tearing phase which causes the separation of the tearing band and lower skirt portion from the upper threaded skirt portion of the capsule.
This breakage is due to the fact that, as the cross-section of the tearing band is situated entirely outwardly of the capsule relative to the weakened zones connecting it to the capsule, when the operation of tearing of the band is initiated, the shearing stress produced in the weakened zones occurs adjacent the part of the cross-section of the tearing band which is subject of the greatest tensile stress.
For this reason, breakage due to shearing in the weakened zones simultaneously initiates breakage of the adjacent part of the band which is subject to tensile stress, which may lead to breakage of the band itself before its removal from the capsule has been completed.
The object of the present invention is to enable plastics materials with a hardness greater than 75 Shore D to be used for the manufacture of tamper-evident capsules of the above-mentioned type, without the risk of breakage of the tearing band during the tearing phase.
According to the present invention, in order to achieve this object, a tamper-evident capsule of the above-mentioned type is characterised in that the capsule is made of a synthetic resin having a hardness greater than 75 Shore D and the tearable opening band extends, at least in part, inwardly of the cylindrical skirt of the capsule relative to the two weakened zones which connect said band to the skirt.
The invention will now be described with reference to the appended drawings, in which:
FIG. 1 is a front elevational view of a capsule,
FIG. 2 is a partial axial section, in an enlarged scale, of the capsule shown in FIG. 1, screwed on the neck of a container,
FIG. 3 is a detail of FIG. 2 on an enlarged scale,
FIG. 4 is a partial view of the interior of the capsule developed in a plane,
FIG. 5 is a section taken on the line V--V of FIG. 4,
FIG. 6 is a perspective view from the interior of a portion
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patent: 4122965 (1978-10-01), Roy
patent: 4127209 (1978-11-01), Ritzenhoff
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patent: 4129226 (1978-12-01), Percival
patent: 4342400 (1982-08-01), Llera
patent: 4417666 (1983-11-01), Roberts
patent: 4449639 (1984-05-01), Davis
patent: 4476987 (1984-12-01), Nolan
patent: 4527705 (1985-07-01), Prades
patent: 4531650 (1985-07-01), Friendship
Alplast S.p.A.
Marcus Stephen
LandOfFree
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