WEIGHT-BASED INTERLOCK APPARATUS AND METHODS

摘要

A weight-based tubular interlock apparatus adapted to determine whether a tubular is engagingly gripped by a rig-based hoisting device or a secondary gripping device is described. The apparatus includes at least two gripping mechanisms and an interlock system operatively connected that is adapted to measure a tubular load on at least one of the gripping mechanisms and to compare the tubular load to a predetermined load to determine whether the at least one gripping mechanism is gripping the tubular. The gripping mechanism is adapted to release the tubular only when the tubular load meets the predetermined load, upon which a release force sufficient to release the tubular from the gripping mechanism is applied to the tubular relative to the gripping mechanism. Methods of using the interlock apparatus are also described.