Abstract: A mechanism for selectively securing a cover to a flange of a pressure vessel. A plurality of such devices can be employed, using a plurality of studs that extend through matching openings in the flange and cover. A movable anchor plate or plates, also with holes through which each stud extends, is disposed adjacent to the flange or cover. The head of each stud will fit through its associated hole of the anchor plate (and into the opening of the closer one of the flange or cover) only if the anchor plate is properly oriented. When the anchor plate is so oriented, a piston head at the opposite end of the stud can be actuated away from the flange and cover to retract the stud head into the opening of the flange or cover. This protects the stud when the cover is disengaged from the flange. The stud can be biased in the opposite direction to permit the anchor plate to be reoriented into a position in which the stud head cannot pass through the anchor plate, so the stud can clamp the flange and cover together.

Abstract: A mechanism for selectively securing a cover to a flange of a pressure vessel. The cover and flange each have openings that are aligned when the cover is in position facing the flange. The mechanism includes an anchor plate having a hole therethrough. A piston is slidable in a direction normal to the cover in alignment with the opening therethrough. A stud extends from to the piston with a stud head remote from the piston. The stud head fits through the opening of the closer of the cover and flange and through a wider portion of the anchor plate hole, and is positioned opposite the flange and cover from the piston when the cover is positioned over the flange. The stud head does not fit through a narrower portion of the anchor plate hole. A resilient member biases the piston away from the cover. A selectively activated actuator overcomes the resilient member and forces the stud head away from the flange and the anchor plate.