Abstract: A torque-transmitting connection for a dual-member drill string. An elongate inner ember of a dual-member pipe is disposed within an outer member and rotatable independent of the outer member. The inner member comprises a geometrically-shaped pin end and a box end having a geometrically-shaped opening. The geometrically-shaped opening of the box end has at least one internal angle greater than 180 degrees. The pin end of the inner member may be inserted into the box end of an adjacent similarly formed inner member to form an inner member pipe joint. The configuration of the pin end and the box end allows the pin end and the box end to be in connector free torque-transmitting engagement but also provides clearance for potential misalignment of the pin end and the box during make-up of an inner member drill string.

Abstract: A spindle assembly for connecting a drill string to a rotational drive for use in a horizontal directional drilling operation. The assembly comprises a saver sub attached to the rotational drive, and a drive chuck for connection to the drill string. The drive chuck and saver sub form a torque-transmitting connection by engaging through a seat in the saver sub and an engagement point on the drive chuck. Dowel pins may be used to rotationally lock and provide the engagement between the saver sub and the drive chuck. A collar may thread to the saver sub and cause an interference fit by engaging the drive chuck at a shoulder.

Abstract: The present invention is directed to a spindle assembly for connecting a drill string to a rotational drive for use in a horizontal directional drilling operation. The assembly comprises a saver sub attached to the rotational drive, and a drive chuck for connection to the drill string. The drive chuck and saver sub form a torque-transmitting connection by engaging through a seat in the saver sub and an engagement point on the drive chuck. Dowel pins may be used to rotationally lock and provide the engagement between the saver sub and the drive chuck. A collar may thread to the saver sub and cause an interference fit by engaging the drive chuck at a shoulder.

Abstract: The present invention is directed to the configuration of an elongate inner member of a dual-member pipe. The elongate inner member of the dual-member pipe is disposed within an outer member and rotatable independent of the outer member. The inner member comprises a geometrically-shaped pin end and a box end having a geometrically-shaped opening. The geometrically-shaped opening of the box end has at least one internal angle greater than 180 degrees. The pin end of the inner member may be inserted into the box end of an adjacent similarly formed inner member to form an inner member pipe joint. The configuration of the pin end and the box end allows the pin end and the box end to be in connector free torque-transmitting engagement but also provides clearance for potential misalignment of the pin end and the box during make-up of an inner member drill string.