Sealing cap with a one way valve having semi-cylindrical valve closure springs

Claim 1

A cap for a container comprising (a) an annular upper member adapted to be positioned in the mouth of the container, said annular member defining a cavity open at the top and having a circular upper wall portion, the outer surface of which is adapted to provide a fluid tight seal against the inner surface of said container when said annular member is pressed into the mouth of said container; (b) a downwardly extending lower member connected to said annular upper member and having a pair of lower member walls spaced from the inner surface of said container when said annular upper member is pressed into the mouth thereof, said lower member walls defining a normally closed slit seal at the bottom end of said lower member; and (c) a pair of flexible spring elements each located on opposite sides of said slit seal and connected to one said lower member wall, each spring element defining an abutment wall intersecting with one said lower member wall along at least two lines of intersection spaced from one another about the midpoint of said slit, each of said abutment walls having a portion aligned with said circular upper wall portion outer surface so as to abut the inner surface of said container when said annular member is pressed into the mouth thereof and each of said abutment walls together with one of said lower member walls, defining an interior volume adjacent the midpoint of said slit seal, each of said lower member walls flexing into a respective said interior volume when said slit seal opens due to the penetration thereof by an instrument.