Patent ID: 8256509

Claim:
A jar comprising: a mandrel, first and second housing members positioned about the mandrel, and a release collet forming an end portion of the first housing member; a release sleeve radially disposed between the mandrel and the release collet and being selectively axially movable relative to the release collet, the release sleeve having an outer diameter portion at which the release collet contracts radially inwardly to engage the release sleeve; a first biasing member positioned in the first housing member to resist axial movement of the mandrel; wherein the release collet includes a plurality of flexible fingers, each finger having at least one inwardly extending tab, and the release sleeve has at least one groove adapted to receive the tabs on the fingers when the release collet and release sleeve move longitudinally with respect to each other; wherein at least one tab on the fingers has a width greater than that of the other tabs on the fingers and at least one groove on the release sleeve is wider than the width of the other grooves on the release sleeve; wherein each of the flexible fingers has an abutment surface on its exterior, distal end, and a wear sleeve within the second housing having an annular abutment shoulder configured to engage the abutment surfaces on the fingers of the release collet prior to release.