A slip spool includes radially disposed actuators for radially moving slip blocks between a loose encirclement position in which they surround the tubing string and a cached position in which the slip blocks clear an axial passage of the slip spool. The slip spool further includes axially disposed actuators...http://www.google.com/patents/US7743856?utm_source=gb-gplus-sharePatent US7743856 - Slip spool assembly and method of using same
