Disposable drinking cup with valved lid

Claim 1

In a disposable drinking cup with a valved, circular lid including a frusto-conical cup having an open top and of a good heat-insulating material, said lid comprising a top wall having a periphery with a skirt depending therefrom, said lid being detachably mounted on said open top by a snap connection including an annular groove in the lid immediately adjacent to the periphery of the lid, said lid being of a flexible elastic plastic having heat-insulating properties, the improvement to the lid comprising: (a) a first arcuate slit, the concave side of said first arcuate slit opening radially inwardly toward the center of said circular lid, the first slit extending through said top wall from its top surface to its under surface in close proximity to the periphery of said circular lid, said slit providing a drinking opening when the material of the top wall adjacent said concave side is depressed, said material providing a valve member which normally resiliently closes said drinking opening; (b) a second arcuate slit, the concave side of said second arcuate slit opening radially inwardly toward the center of said circular lid, the second slit extending through said top wall from its top surface to its under surface in a position diametrically opposite the first slit providing the drinking opening, and which defines a relief opening when the material of the top wall adjacent said concave side of the second slit is depressed, said material providing a relief valve which normally resiliently closes said relief opening; (c) a straight reinforcing rib upstanding from said top wall and extending between said valve member and said relief valve with one end portion of said rib terminating within the area defined and bordered by said first arcuate slit and with the remaining end portion of said rib terminating within the area defined and bordered by said second arcuate slit, the area defined and bordered by the first and second arcuate slits being bounded by an imaginary straight line connecting the end points of the arcs of the respective first and second arcuate slits whereby downward pressure on said rib causes deflection of said top wall to move said valve member and said relief valve, opening said drinking opening and said relief opening; and (d) a generally circular reinforcing rib upstanding from said top wall and radially inwardly of and concentric with said periphery and spaced radially outwardly of said relief opening with the generally circular formation of said reinforcing rib being interrupted by a U-shaped formation, the open end of said U-shaped formation being directed radially outwardly toward said first arcuate slit, the interposition of said U-shaped formation preventing the otherwise intersection of said generally circular reinforcing rib and said first arcuate slit.