Patent ID: 8376041

Claim:
An apparatus for engaging with an outside diameter of a tubular, comprising: at least one device body having an internal surface, the internal surface defining an internal diameter in a first position and allowing the tubular to pass therethrough; an actuator operable to move the internal surface of the at least one device body from the first position to a second position, the second position defining an internal diameter less than the first position internal diameter, wherein the internal surface of the device body is sized with a predetermined grip length for engaging with the outside diameter of the tubular, the grip length determined by a function of the outside diameter of the tubular and the coefficient of friction between of the outside diameter of the tubular and the interior surface of the device body and wherein the device body is operable to engage with a tubular having a predetermined range of outside diameters, wherein the predetermined grip length, L, is determined by the equation L = D 4 ⁢ μ , wherein D is the outside diameter of the tubular and μ is the coefficient of friction.