Patent ID: 6068066
Filing Date: 2000-05-30
Classification: E21B

Abstract:
A drilling or service rig comprising:(a) a rig substructure comprising a drill floor having a drill opening;(b) at least three structural towers fixedly mounted to the rig substructure and projecting vertically above the drill floor, said towers being in spaced relationship to each other and encircling the drill opening;(c) a plurality of hydraulically-actuated, telescoping lifting rams corresponding in number to the number of towers, said lifting rams being fixedly mounted at their lower ends to the rig substructure and projecting vertically above the drill floor, and each lifting ram being in proximal association with one of the towers;(d) lateral support means associated with the towers for providing lateral support to the lifting rams throughout their range of telescoping operation;(e) hydraulic power means for actuating the lifting rams such that the lifting rams may operate substantially in unison;(f) a roof platform affixed to and supported by the upper ends of the lifting rams, said roof platform comprising a substantially horizontal cradle track;(g) a cradle having means for engaging the cradle track such that the cradle may be mounted to and moved along the cradle track;(h) cradle actuation means mounted to the roof platform, for moving the cradle along the cradle track; and(i) a drilling hook associated with the cradle, for vertically supporting a drill string plus accessory components and pipe-handling tools or service equipment.