Releasable locking device

A device for removably connecting an end fitting to a nuclear fuel assembly support structure, the support structure comprising at least one longitudinally extending post and the end fitting comprising a laterally extending plate, said post being fixed in the assembly support structure to prevent rotation about the post's axis relative to the assembly support structure, the device comprising:

• a longitudinally extending connecting post threadably connected to one end of said support structure post;
• means associated with said connecting post for connecting the laterally extending plate to and positioning it relative to the longitudinally extending support structure post;
• a first washer concentrically positioned about said connecting post and having a plurality of ratchet teeth having inclined surfaces extending longitudinally therefrom in a first longitudinal direction;
• means connecting the support structure and the first washer for supporting said first washer independently of said connecting post and for preventing relative rotation between said first washer and said support structure post;
• a second washer concentrically positioned about said connecting post and having a plurality of ratchet teeth having inclined surfaces complimentary with said inclined surfaces of said ratchet teeth of said first washer extending longitudinally therefrom in the longitudinal direction opposite from said first direction, said second washer being longitudinally positioned with respect to said first washer so as to permit said inclined surfaces of said ratchet teeth of said first washer and said second washer to mate with one another;
• means associated with said connecting post for supporting said second washer to prevent relative rotational movement between said second washer and said connecting post;
• at least one of said first washer and said second washer being longitudinally movably relative to said connecting post to move said ratchet teeth of said first and second washers into and out of mating engagement,
• means for normally biasing said first washer and said second washer toward one another to mate said inclined surfaces thereof, said inclined surfaces when mated acting to transmit the biasing force of said biasing means to urge relative rotation of said first and second washer in one direction and prevent relative rotation in the other direction to tighten the threaded connection of said connecting post to said support structure post and to prevent retrograde rotation of said connecting post, said biasing means being releasable to permit said washers to be moved out of mating engagement and thereby permit free rotational movement of said connecting post.