Patent ID: 7527093

Claim:
An apparatus for supporting a tubular in a borehole, comprising: a base having an opening for receiving a tubular; a first gripping member and a second gripping member, each adapted to frictionally engage the tubular; a first pivot arm including at least one parallel linkage pivotally secured to the base at a lower pivot pair and pivotally secured to the first gripping member at an upper pivot pair positionable above the lower pivot pair; a second pivot arm including at least one parallel linkage pivotally secured to the base at a lower pivot pair and pivotally secured to the second gripping member at an upper pivot pair positionable above the lower pivot pair; and an actuator comprising: a threaded rod having a first threaded portion and a second threaded portion; a first threaded guide member threadably coupled to the first threaded portion of the threaded rod; a first connecting link pivotally secured to the first threaded guide member at a first end and pivotally secured to the first pivot arm at a second end; a second threaded guide member threadably coupled to the second threaded portion of the threaded rod; and a second connecting link pivotally secured to the second threaded guide member at a first end and pivotally secured to the second pivot arm at a second end; wherein the first and second threaded portions are reverse-threaded; and wherein rotation of the threaded rod positions the first and second gripping members.