US Patent 7204384 Dual cover system with clamping closure mechanism

In a cover of a container for a dual cover system, wherein the cover and container have both either a round or a polygonal shape with a seal arranged between the container and the cover and wherein the cover includes at least two clamping closure mechanisms operable by an operating structure arranged in the center of the cover and having operating arms extending to the clamping closure mechanisms for synchronous operation thereof, each clamping closure mechanism includes an outwardly extending elbow lever structure with an upper pivotal support bearing on the cover and a lower pivotal support bearing mounted on a support arm movable up and downwardly by the operating structure.