Torque and torsion limiting tool

Abstract

A downhole tool () particularly for controlling torque and torsion and also for absorbing/dampening vibration in a downhole string is provided and comprises an inner mandrel () and an outer mandrel () and a coupling mechanism () to couple the inner and the outer mandrel, the coupling mechanism comprising one or more longitudinally elongate members () acting between the inner and outer mandrel, wherein the one or more longitudinally elongate members are substantially fixed in their longitudinal length but substantially do not resist relative compressive longitudinal movement occurring between the inner and outer mandrels. The coupling mechanism is arranged such that compression of the inner and outer mandrels results in compression of the one or more longitudinally elongate members without necessarily resulting in relative rotation of the inner and outer mandrels.