Patent ID: 7918273

Claim:
An apparatus for providing selective rotation to an oilfield tubular string at a wellbore, the apparatus comprising: a top drive for providing rotational energy, wherein the top drive is operatively connected to a rig at the wellbore; a torque head having at least one radially movable gripping member for selectively gripping the oilfield tubular string; and a coupler device having a first configuration for transmitting the rotational energy from the top drive to the torque head to rotate the torque head at a first torque and a second configuration for altering such transmission, while the coupler device is in a rotational state, to rotate the torque head at a second torque that is different than the first torque, wherein the coupler device is operatively connected to the top drive and the torque head when in the first configuration and the second configuration, and wherein the coupler device includes a fluid flow path that provides fluid communication between the top drive and the torque head.