US Patent 9057234 Circumferential cams for mechanical case running tool

A casing running tool is provided having both axial and circumferentially tapered elements. In certain embodiments, the casing running tool comprises cam structures that are circumferentially tapered so as to allow an applied torque to engage and disengage the casing running tool with a casing or liner. In embodiments, the circumferential taper of the cam structures allows a mandrel or rollers disposed between the mandrel and cam structures to apply radial force to corresponding shoe structures which in turn engage or disengage the casing or liner. The cam structures may also exhibit an axial taper to allow for a self-energized fail-sage operation of the casing running tool.