Automatic sequencing system for earth drilling machine

摘要

An earth drilling machine of the type having a boom mounted adjacent a mast to move a tubular between a lower, horizontal boom position and an upper, vertical boom position also includes a lifter configured to move a length of downhole tubular between a lower lifter position aligned with a tubular storage device and an upper lifter position aligned with the lower boom position. An automatic sequencing system includes multiple position sensors responsive to the position of at least the boom, the lifter and a length of downhole tubular at selected positions. A sequencing system is responsive to the position sensors for automatically coordinating movement of the lifter and the boom to reduce or eliminate delays occasioned by tubular handling.