Improved quick opening closures are disclosed. The closures may include a hub and a door hingedly attached to the hub by hinge arms. A seal is disposed around the door. The hinge arms may be mounted to door blocks that are attached to and substantially centered on the door. At least one support post may be connected between the hinge arms. An activation bar may be pivotally connected to a support post, such as with a pivot bracket. The activation bar is used to evenly apply closing force to the door through the centralized hinge blocks to evenly compress the seal between the door and the hub. The activation bar may also be used to pull the door out of engagement with the hub toward its open position. Various devices may connect a distal end of the activation bar to the hub to assist in opening/closing the door.