| 摘要 |
<p>A drilling apparatus (1) is for use on a rotary drilling rig with a top drive which enables circulation and rotation of a drill string (3) to continue uninterrupted during the making of drill string connections. It has a snubber gripping mechanism (10, 9) to enable tool joints (2, 3) to be supported and gripped with a reduced pressure chamber (5) volume and snubbing force, during tool joint connections. The gripping mechanism has gripping pads (14) arranged to move radially by relative rotation of a drive cylinder (34) causing a tapered surface (36) of the drive cylinder (34) to press against or release the pad (14). A guide cylinder (30) supports and guides the pads (14) and collets (13) for retaining a drill string at an upset shoulder (19).</p> |
