TOP HEAD DRIVE ASSEMBLY FOR EARTH DRILLING MACHINE AND COMPONENTS THEREOF

摘要

A top head drive assembly (14) for a drilling machine (10) includes a wrench assembly used to make up and break out threaded connections. This wrench assembly (50) is mounted for axial movement on rails (66) of the top head drive assembly, and is positioned immediately under the quill (30). The top head drive assembly (14) also includes a tubular support assembly (90) which includes slip type inserts (120) for supporting a string of down hole tubulars (32, 34). This support assembly (90) can be pivoted (via 132) out of alignment with the drilling axis or can be locked (via 134) in alignment with the drilling axis. A plurality of centering elements (152) are mounted under the support assembly (90) and are movable to center the upper end of the tubular for insertion into the tubular support assembly (90). Preferably, both the top head drive assembly load beam (16) and the support beam (92) of the support assembly (90) are formed of box sections having converging side plates (not referenced; 100) and internal diagonal brace plates (182; 106) which transmit downard forces on the beam into forces tending to cause the side plates to diverge. Divergence of the side plates is prevented by support plates (not referenced; 110) which surround the beam.