Unrestricted bore safety joint

摘要

An apparatus, such as a shear-out safety joint, which is incorporated in a subterranean well tubing string for separating or severing the tubing string when subjected to excessive loads is disclosed. The shear-out safety joint is used with a safety valve and by providing a prescribed failure point will ensure that the safety valve remains intact. The apparatus includes inner and outer telescoping members which can separate when the tubing above and below the joint moves in opposite directions. A shear ring connecting the two telescoping members will shear when a predetermined load is applied. The joint also has a second releasable connecting member extending through the inner telescoping member and engaging the outer telescoping member which will support a load greater than that which can be carried by the shear ring. A longitudinally shiftable member, movable within a recess, holds the second connecting member in engagement but disengages the second connecting member when moved to a second position.