SAFETY JOINT Russian patent published in 2006 - IPC E21B17/06 

FIELD: safety means, particularly releasing-joints adapted to disconnect free pipe string part from that stuck inside well.

SUBSTANCE: safety joint comprises composite body including upper and lower parts and sealing unit arranged between the parts over torque transmission unit, which connects body parts and formed as spline connection. Joint also has seat for free fall valve and axial load transmission unit made as collet with extensions on outer surface of springing leafs. Solid collet end is connected with upper body part. Collet extensions are arranged in annular groove formed in inner surface of lower bode part. Collet extensions are fixed in working position by free-fall valve seat, wherein the valve is retained by compression spring installed on stop ring rigidly connected to lower body part. Split collet part has inner conical surface. Free-fall valve seat has mating outer surface.

EFFECT: increased operational reliability and simplified safety joint manufacture.

2 dwg