| CPC E21B 19/16 (2013.01) [E21B 7/046 (2013.01); E21B 7/28 (2013.01); E21B 19/08 (2013.01)] | 18 Claims |

|
1. A horizontal directional drilling system, comprising:
a drill string having multiple segments;
a drilling machine comprising:
a carriage supported on a drill frame and movable relative to the drill frame;
a motor supported on the carriage having an output member configured to connect with and selectively drive rotation of the drill string, wherein the motor is operable in a first mode and a second mode;
wherein the first mode is characterized by the motor applying torque to the drill string through the output member;
wherein the second mode is characterized by the motor being disabled from applying rotational torque to the drill string; and
wherein the system is configured to:
provide thrust with the carriage and rotate the drill string with the output member when the motor is in the first mode; and
provide thrust with the carriage but not rotate the drill string with the output member when the motor is in the second mode; and
wherein the drill string is configured for simultaneous connection to the drilling machine and a second drilling machine, and to receive thrust from the second drilling machine and the drilling machine when the drilling machine is in the first mode.
|