Patent ID: 8784000

Claim:
A manhole cover adapted to move from a seated position to an unseated position with respect to a frame to relieve pressure, the frame having a manhole cover receiving surface and a peripheral wall defining an access opening, said manhole cover comprising: a cover portion having an upper face, an outer peripheral edge, and an underside opposing said upper face, said cover defining an opening extending through said cover; a first leg and a control leg extending from said cover portion whereby said control leg is configurable between a restraint mode and a removal mode, wherein said first leg and said control leg extend away from said underside toward said access opening and each includes a foot at a first end thereof, said feet of said first leg and said control leg projecting radially outwardly underneath the peripheral wall in said restraint mode; whereby in response to pressure on said underside reaching a threshold in said restraint mode, at least a portion of said cover portion displaces from said seated position to said unseated position such that fluid flows through the access opening; wherein in said unseated position and in said restraint mode, said first leg, said control leg, and said feet cooperate with the frame to enable said at least a portion of said cover portion to have a range of movement with respect to the manhole receiving flange, wherein said feet contact the frame at a limit of said range to prevent said cover portion from moving beyond said limit of said range; and wherein in said removal mode said control leg is slidable within said opening in said cover such that said control leg is movable away from the frame to enable removal of said manhole cover therefrom.