Radially moving slips

A slips system for engaging and securing a drill string comprising a plurality of tubulars having tool joints, each tool joint including a vertically extending surface portion and a shoulder portion comprising:

• (a) a first set of slips positioned for movement toward and away from said vertically extending surface portion;
• (b) a second set of failsafe slips positioned for movement toward and away from said shoulder portion;
• and
• (c) power actuator means connected to said slips for moving said first set of slips into gripping engagement with said vertical surface portions of the tubulars and for moving said second set of slips into engagement with said shoulder portion.

A slip assembly for gripping a tubular having a longitudinal axis comprising:

• (a) a plurality of tubular-gripping slips disposed about said tubular:
• (b) a support;
• (c) means mounted on said support for moving said slips radially into contact with, and away from, said tubular;
• and
• (d) a plurality of links each having one end pivotally mounted on one of said slips and the other end pivotally mounted on said support, the arrangement being such that, in use, said links constrain the vertical movement of said slips such that said slips move substantially purely radially and engage said tubular with a force substantially perpendicular to the longitudinal axis thereof.

A slips assembly comprising:

• (a) a plurality of tubular-gripping slips mounted for radial movement about a tubular;
• (b) moving means for moving said slips in a substantially purely radial motion whereby said slips do not damage said tubular in engaging and vertically securing said tubular;
• and
• (c) wherein said slips assembly includes a sloping external surface on said slips, and in which said moving means includes wedge means which contact said sloping surface for moving said slips in a substantially purely horizontal plane.