Locking lid for overfill-spillage protection system

Claim 1

A locking lid assembly for use in closing the open top of a cylindrical stack of a spill containment chamber or the like, said locking lid assembly comprising an annular base member adapted to be seated upon the top of said stack with said base member extending around the outer periphery of said stack and projecting upwardly above the top of said stack, a cover lid mounted on said base member for hinging movement about a hinge axis extending generally tangentially of said base member between a closed position wherein said lid overlies said base member and an open position wherein said lid is hinged upwardly about said hinge axis from said closed position, resilient annular sealing means engageable between said lid and the upper surface of said base member to define a continuous annular fluid-tight seal between said lid and said base member when said lid is in its closed position, a pair of locking pins projecting radially outwardly from said base member at diametrically opposed locations, a pair of locking cams pivotally mounted at diametrically opposite sides of said lid for pivotal movement about a pivot axis parallel to said hinge axis and above the top of said lid, said cams each including an arm portion extending generally radially from said pivot axis in a first direction and a locking pin engaging cam portion radially offset from said pivot axis and angularly displaced about said hinge axis from said arm portion, said cams being pivotal, when said lid is in its closed position, between a cam release position and a locking pin engaging lock position, said arm portions of said cams when in said release position projecting upwardly above the top of said lid and said cam portions being disengaged from said locking pins to accommodate movement of said lid to its open position, said cams when in said lock position having their arm portions extending generally parallel to the top of said lid and said cam portions wedgingly engaged beneath said locking pins to compresss said annular sealing means between said lid and base member.