Top head drive assembly for earth drilling machine and components thereof

In a top head drive assembly for an earth drilling machine of the type comprising a load beam, means for guiding the load beam for movement along a mast, a quill supported on the load beam, and means for rotating the quill, the improvement comprising:

• a pair of spaced support rails suspended from the load beam;
• a wrench assembly comprising:
• an upper clamp adapted to clamp an upper tubular;
• a lower clamp adapted to clamp a lower tubular;
• and
• means, coupled between the upper and lower clamps, for rotating one with respect to the other to torque one of the upper and lower tubulars with respect to the other;
• means for guiding the wrench assembly along the rails under the quill;
• means for moving the wrench assembly along the rails;
• a tubular support assembly comprising:
• a support beam;
• means, mounted on the support beam, for releasably supporting a tubular;
• and
• means for controlling the support means to selectively release and engage the tubular;
• means for pivotably mounting the tubular support assembly from the rails;
• and
• means for pivoting the tubular support assembly between an operative position aligned with an axis defined by the quill under the wrench assembly and a storage position laterally offset from the wrench assembly.

An apparatus for supporting a down hole tubular beneath a top head drive assembly of an earth drilling machine, said top head drive assembly defining a drilling axis, said apparatus comprising:

• means for engaging and supporting an upper end portion of a length of down hole tubular;
• means for supporting the engaging means under the top head drive assembly;
• means, included in the supporting means, for positively locking the engaging means in alignment with the drilling axis;
• and
• means for centering a down hole tubular under the engaging means, said centering means comprising:
• a plurality of pairs of opposed centering elements;
• means for pivotably mounting the centering elements under the engaging means such that the centering elements are movable to approach and move away from the drilling axis;
• and
• means for moving the centering elements toward the drilling axis to center a length of down hole tubular under the engaging means.

A top head drive assembly for an earth drilling machine of the type comprising a load beam, means for guiding the load beam for movement along a mast, a quill supported on the load beam, and means for rotating the quill, wherein the load beam comprises:

• a quill support member adapted to support the quill for rotation;
• a box section disposed around said quill support member, said box section tapering in width from the quill support member to each end;
• first and second diagonal braces disposed in the box section, each tapering in width from a wider upper end which abuts the quill support member to a narrower, lower end situated adjacent a lower portion of a respective one of the ends of the box section;
• and
• at least one pair of support elements, each positioned to surround the box section adjacent a respective end to resist any increase in width of the box section;
• said braces positioned such that downward forces on the quill support member tend to increase the width of the box section adjacent the support elements.