One-piece dispensing closure

A closure for a container, said closure comprising in combination:

• a cap having an outer surface and an annular opening including an inner edge which defines a lip;
• a cap like member including a resilient and deformable substantially circular end wall having a depending peripheral skirt, said end wall having an outer surface and an inner surface, said end wall including a scoreline having a reduced wall thickness carried on its said outer surface which scoreline defines a segment intersecting less than about 170.degree. of circumferential arc of said substantially circular end wall, said peripheral skirt terminating in a portion having a bottom surface of a size and construction for sealing it to the outer surface of said cap around said annular opening;
• a resilient and deformable complex seal depending from said inner surface of said end wall in substantial spaced concentric relation to said peripheral skirt, said seal positioned and sized for insertion into said annular opening of said cap, said seal further being comprised of a first and a second body portion, said first body portion of said seal immediately adjacent to and depending from said inner surface of said end wall being substantially in the form of a hollow cone having an inner surface, an outer surface and a base, which cone increases in diameter as its distance from said end wall increases, while said second body portion of said seal begins at and is integral with said base of said cone and is substantially in the form of a hollow cylinder having a base and having substantially the same diameter as the diameter of said base of said cone, said complex seal further having a tapered external lip for normally forming a partially releasable seal with said lip of the annular opening, said tapered external lip being substantially circumferentially around and carried by said hollow cylindrical second body portion of said seal;
• a dispensing opening through said end wall substantially within said segment defined by said scoreline and inter-mediate said peripheral skirt and said outer surface of said cone;
• whereby when inward pressure is exerted on said end wall in the vicinity of said scoreline a substantial portion of said end wall within said scoreline is moved inwardly, the portion of said seal which is in substantial registration with said scoreline is moved inwardly with said end wall and a substantial portion of said tapered lip carried by said inwardly moved portion of said seal is also moved inwardly and thereby released from sealing relation with said inner surface of said outlet with which it is normally sealed, while the portion of said seal which is outside of said scoreline remains substantially unmoved and the portion of said tapererd lip carried by said unmoved portion of said seal also remains substantially unmoved and in sealing relation with said lip of said annular opening, and whereby further, when inward pressure on said end wall is terminated said inwardly moved portion of said end wall and said seal quickly move outward and return said inwardly moved portion of said tapered lip to its normal sealing relation with said lip of said annular opening.