Abstract: A male member has a cylindrical core with an internal poppet that is displaced by air pressure to open an air passage for pressurized air to an end of the poppet. The female cavity and poppet form a container bottom wall. A thermoplastic copolymer polyethylene is injected into the mold at about 470.degree. F., the mold having a surface temperature of about 100.degree.-130.degree. F. and the plastic material a temperature of about 130.degree.-160.degree. F. at the time of ejection of the container from the mold. Ribs are formed at the container rim having a depth such as to cause the container to stretch about 6% when removed from the core. The ribs outer edges are coextensive with the container side wall. A lid engaging lip is formed at the container rim edge. The process has a preferred 14 second cycle time and uses a core with no draft. The mold surface is maintained at the desired temperature by a cooling water circuit in the mold.

Abstract: There is disclosed a novel cover and container assembly having a container portion and a cover portion wherein there is formed a bellows-like portion of at least two annular grooves separated by a ridge on the cover or container portion for dampening external pressure forces after impact and further having an interlocking assembly providing a contact area between the cover and the container. The interlocking assembly provides a snap-type closing which ensures a tighter fit with less chance of opening with one annular groove including rib members located near the edge of the cover, with the rib members providing means for separating the cover from the container.

Abstract: An improved cover and can assembly having a novel interlocking assembly comprised of a two "ball and socket" configuration thereby providing a greater surface or contact area between the cover or lid and the container. The novel interlocking assembly provides a snap-type closing which insures a tighter fit with far less chance of opening with the cover being provided with an annular groove including rib members located near the edge of the cover with the rib members providing means for separating the cover from the container.