Stress concentrator aperture-forming means for sealed containers and packages

A container for a flowable substance, comprising;

• a substantially flat sheet member formed from a relatively thin, relatively flexible material and made integral with a surface of said container;
• a stress concentrator aperture-forming means provided in said sheet member comprising at least one elongated thin-walled protrusion member projecting from one surface of said sheet member and having a generally channel-shaped configuration;
• said sheet member including a substantially flat peripheral portion around said stress concentrator aperture-forming means;
• and
• a fault line of predetermined length traversing said channel-shaped stress concentrator protrusion member;
• wherein upon application of pressure to said container said channel-shaped stress concentrator aperture-forming means ruptures along said fault line forming said aperture opening through which said flowable substance flows, wherein said channel-shaped stress concentrator means is covered by a guard cover, wherein said guard cover has an interior side in contact with said channel-shaped stress concentrator means.

A stress concentrator expandable aperture-forming member for packages or containers for a flowable substance, comprising:

• a substantially flat relatively stiff sheet member formed from a relatively thin, relatively flexible material;
• a stress concentrator aperture-forming means provided in said sheet member comprising at least one elongated thin-walled protrusion member projecting from one surface of said sheet member and having a generally channel-shaped configuration;
• said sheet member including a substantially flat peripheral edge portion around said stress concentrator aperture forming means;
• and
• a fault line of predetermined length traversing said channel-shaped stress concentrator protrusion member;
• whereby upon rupture of said fault line, said channel-shaped stress concentrator aperture-forming means forms a relatively flexible and expandable aperture opening,
• wherein said container defines a slit opening;
• wherein said stress concentrating aperture-forming member is positioned within said container, wherein said one surface of said substantially flat sheet member is positioned along the interior surface of said container beneath said slit opening;
• wherein said stress concentrating aperture-forming member is secured to said interior surface of said container around said slit opening, wherein said slit opening is not in direct contact with said flowable substance in said container;
• and
• wherein upon rupture of said channel-shaped stress concentrator means across said fault line, said flowable substance within said container flows through said stress concentrator aperture-forming means and said slit opening when pressure is applied to said container.