Patent EA-003564-B1 (EA)
Title: Stud tensioning device for flange cover
Inventor: MALSBURY ALLEN S
IPC: G21C13/06
Filed: 2000-04-14
Abstract: 1. A mechanism for selectively securing a cover (14) to a flange (12) of a pressure vessel (15), the cover (14) and flange (12) each having at least one opening there through, the respective openings being aligned when the cover (14) is properly positioned facing the flange (12), the mechanism comprising: a stud (10) extending through the opening of one of the flange (12) and the cover (14), the stud (10) having a stud head (42) at one end and a piston head (10a) at the other end, the stud head (42) being sized to fit longitudinally through the opening of the other of the flange (12) and the cover (14); a selectively movable anchor plate (18) disposed opposite to the other of the flange (12) and the cover (14) from the one of the flange (12) and the rover (14), the anchor plate (18) having a hole through which the stud (10) can extend when the cover (14) is positioned facing the flange (12), the hole having (i) a wider portion through which the stud head (42) can pass longitudinally and (ii) a narrower portion through which the stud head (42) cannot pass longitudinally, the anchor plate (18) bring movable between a first position, in which the narrower portion of the hole is aligned with the openings of the cover (14) and flange (12), and a second position, in which the wider portion of the hole is aligned with the openings of the cover (14) and flange (12); and a cylinder (10b) in which the piston head (10a) is mounted so as to be slidable substantially normal to the one of the flange (12) and the cover (14), the cylinder (10b) including a mechanical stop (10c) that limits movement of the piston head (10a) relative to the cylinder (10b) in a direction toward the anchor plate (18), the cylinder (10b) being selectively movable relative to the anchor plate (18) in a direction away from the anchor plate (18), when the anchor plate (18) is in the first position and the piston head (10a) is against the mechanical stop (10c), so as to draw the stud head (42) against the anchor plate (18) to clamp the cover (14) and the flange (12) together, and the piston head (10a) being selectively movable away from the mechanical stop (10c), when the anchor plate (18) is in the second position, so as to retract the stud head (42) into the opening of the other of the flange (12) and the cover (14). 2. The mechanism of claim 1, wherein the cylinder (10b) is mounted opposite to the cover (14) and the flange (12) from the anchor plate (18). 3. The mechanism of claim 2, further comprising a piston (34) in which the cylinder (10b) is formed. 4. The mechanism of claim 2 further comprising an outer cylinder (26) in which the piston (34) is slidably mounted. 5. The mechanism of claim 4, further comprising a pair of hydraulic fluid ports (32a, 32b) into the outer cylinder (26), the ports being located on opposite sides of the piston (34). 6. The mechanism of claim 3, further comprising a resilient member (16) biasing the piston (34) away from the one of the cover (14) and the flange (12). 7. The mechanism of claim 6, wherein the resilient member (16) is a spring washer adjacent to the piston (34) and through which tire stud (10) extends, the spring washer being disposed so as to be compressed when the piston (34) is forced toward the one of the cover (14) and the flange (12). 8. The mechanism of claim 2, wherein the mechanical stop (10c) is formed at a constriction from a wider portion of the cylinder (10b), in which the piston head (10a) is disposed, to a narrower portion of the cylinder (10b), through which the stud (10) extends. 9. The mechanism of claim 1, wherein the anchor plate (18) is disposed opposite to the other of the flange (12) and the cover (14) from the cylinder (10b). 10. The mechanism of claim 9, further comprising: a hydraulic cylinder (26) mounted to one of the cover (14) and the flange (12) opposite from the other of the cover (14) and the flange (12); and a piston (34) mounted for slidable movement within the hydraulic cylinder (26) in a direction substantially normal to the one of the cover (14) and the flange (12), wherein the cylinder (10b) is formed in the piston (34), is aligned with the opening of the one of the cover (14) and the flange (12) , and is movable between a locking position and an unlocking position, the locking position being farther from the one of the cover (14) and the flange (12) than is the unlocking position, and the piston head (10a) moves within the cylinder (10b) of the piston (34) between an extended position and a retracted position relative to the piston (34), the extended position being closer to the one of the cover (14) and the flange (12) than is the retracted position. 11. The mechanism of claim 10, wherein, when the piston head (10a) is in the extended position, (i) the stud (10) can extend through the openings of the cover (14) and flange (12) and through the hole of the anchor plate (18) with the stud head (42) spaced from the anchor plate (18),if the piston (34) is in the unlocking position, and (ii) the stud (10) can extend through the openings of the cover (14) and flange (12) and through the hole of the anchor plate (18) with the stud head (42) clamped against the anchor plate (18) if the piston (34) is biased toward the locking position and the narrower portion of the hole is aligned with the opening of the flange (12). 12. The mechanism of claim 11, further comprising a pair of hydraulic fluid ports (32a, 32b) into the hydraulic cylinder (26), the ports being located on opposite sides of the piston (34). 13. The mechanism of claim 1, further comprising at least one piston (34) secured to the other of the cover (14) and the flange (12) so as to be slidable in a direction substantially normal to the other of the cover (14) and the flange (12) in alignment with the opening there through, the piston head (10a) being mounted for slidable movement relative to the piston (34). 14. The mechanism of claim 13, further comprising: a resilient member (16) biasing the piston (34) away from the other of the cover (14) and the flange (12) so as to bias the stud head (42) toward the one of the cover (14) and the flange (12); a first selectively activated actuator for overcoming the bias of the resilient member (16) to force the piston (34) toward the other of the cover (14) and the flange (12) and to force the piston head (10a) toward at least one of the cover (14) and the flange (12) relative to the piston (34); and. a second selectively activated actuator for biasing the piston head (10a) away from the other of the cover (14) and the flange (12) relative to the piston (34), wherein, with the anchor plate (18) in the first position and the stud head (42) apposite to the anchor plate (18) from the piston (34), deactivating the first actuator permits the resilient member (16) to bias the stud head (42) against the anchor plate (18) to clamp the cover (14) and flange (12) together, and with the anchor plate (18) in the second position, deactivating the first actuator and activating the second actuator retracts the scud head (42) through the wider portion of the anchor plate (18) hole and into the opening of the one of the cover (14) and the flange (12) so that the cover (14) and the flange (12) can be separated. 15. The mechanism of claim 14, wherein the first actuator and the second actuator comprise means for introducing hydraulic fluid into the hydraulic cylinder (26) on opposite sides of the piston (34). 16. The mechanism of claim 14, wherein the cover (14) and the flange (12) have matching pluralities of the openings, the anchor plate (18) has a corresponding plurality of the holes, and the mechanism comprises a corresponding plurality of the studs 10. 17. The mechanism of claim 16, wherein the mechanism comprises a plurality of the pistons (34), each of the studs (10) being secured to a different one of the pistons (34). 18. The mechanism of claim 17, wherein at least one of the selectively activated actuators includes a piston actuator that simultaneously engages more than one of the pistons (34). 19. The mechanism of claim 18, wherein the anchor plate (18) and the piston actuator are substantially annular, and the piston actuator simultaneously engages all of the plural pistons (34). 20. The mechanism of claim 14, wherein the anchor plate (18) is substantially annular and rotatable circumferentially relative the pressure vessel (15) between the first and second positions. 21. The mechanism of claim 14, wherein the piston head (10a) of the stud (10) is mounted for slidable movement within the piston (34) in the direction of the movement of the piston (34), the stud head (42) and the piston (34) is positionable on opposite sides of the cover (14) and flange (12) when the cover (14) is positioned facing the flange (12). 22. The mechanism of claim 21, wherein the pressure vessel (15) and the cover (14) are each substantially circular in cross section, the flange (12) and the anchor plate (18) are each substantially annular, the openings, the holes and the studs (10) are distributed around the periphery of the pressure vessel (15), and the piston actuator is substantially annular and simultaneously engages all of the pistons (34).