Link control system for use with dual elevators

摘要

An improved apparatus for handling strings of drill pipe in a drilling rig including a lift member elevationally positionable over a borehole, a pair of links pivotally supported at their upper ends to the lifting member and having open loops at their upper ends to the lifting member and having open loops at their lower ends, cable means extending from the drill rig floor to upward attachment providing means to guide the lifting means and thereby the link in vertical alignment relative to the borehole, a cylinder-piston extending from the lifting member to the links so that the lower ends thereof can be remotely controlled to and move towards or away from each other; and a second cylinder extending from the lifting member to selectively pivot the links in a common plane from the vertical to an inclined angle.