Rotary percussive drill rig - with saline coupling between shank end and air or water swivel

摘要

A drill rig with a percussive hammer and a shank end which transmits the hammer blows to the air or water swivel at the top end of the drill string has splines at the shank end which engage into the splines in the swivel. A locking device which prevents the extraction of the shank end consists of a ring which fits into an undercut above the splines and is itself held in position by two dowels. Contrary to a threaded coupling, this allows a broken shank end (which is a highly stressed part) to be removed without trouble.