Lid for a drinking cup

Claim 1

A lid for removable mounting on the rim of a drinking cup, the lid comprising: (a) a substantially planar center section adapted to conform substantially to an area defined by the interior of the rim of the cup; (b) a peripheral section delimiting said center section and adapted to fit snugly over said rim of the cup, the peripheral section consisting of an annular inner wall segment rising substantially vertically from the edge of the center section, an annular outer wall segment depending a substantial distance from the exterior of said rim of the cup to form a seal with the lower lip of a person drinking from the cup, and a bight segment connecting the upper edges of the inner and outer wall segments; (c) a stiffening rib formed along a portion of the peripheral section adjacent the confluence of the bottom edge of said inner wall segment of said peripheral section with said substantially planar center section; (d) an elongated U-shaped slit in said center section describing a resilient drinking portion in the center section, the bight portion connecting the two legs of said U-shaped slit being juxtaposed said stiffening rib and beveled at an angle not to exceed about 45° relative to the exposed surface of said center section; (e) elevated breathing means formed in said center section diametrically opposite said elongated U-shaped slit, said breathing means preventing the occurrence of a vacuum-like condition within the cup during drinking from the cup; and (f) a protuberance formed in said center section substantially equidistant from the ends of said U-shaped slit and spaced away from the bottom of said U-shaped slit, the protuberance projecting upward a substantial distance from said center section but not exceeding the height of said inner wall segment of the peripheral section, the protuberance having a hollow interior adapted to communicate with the interior of the cup when the lid is mounted on the rim of the cup and sized relative to the drinking portion so that the latter is substantially open upon a predetermined depressing force being applied to the protuberance by the upper lip of a person drinking from the cup.