Abstract: A plastic closure adapted for frictional mounting upon the rim of a cup or the like has an upstanding brim extending about a central panel, which brim has a downwardly opening channel therein for seating the cup rim. A series of discrete compound protuberances project into the channel from the outside wall of the brim, and provide a discontinuous bead which engages the rim of the cup. The protuberances are configured to afford facile mounting on the cup and secure retention thereon while, at the same time, ensuring ready stripping from the male forming member on which the closure is molded. The inside wall of the closure is configured to ensure close fitting sealing engagement with the inner surface of the cup, and is dimensioned to do so without causing buckling, such as would, in turn, tend to produce leakage from the closed container. In general, the configuration of the closure adapts it for use with containers having a variety of rim configurations and a range of dimensions.

Abstract: Effective means for insuring predetermined axial spacing between parts in stacks, particularly in stacks of nesting, relatively large, thin-walled flexible parts and for maintaining positive alignment of the parts in stacks without causing undue difficulty when parts are being separated are provided. More specifically, plastic covers for plates or the like having specially constructed stack shoulders and stack stabilizers are provided.