Patent ID: 7654342

Claim:
An underreaming tool for use in a borehole, comprising a tubular body, a drive tube, at least one blade element, at least one wedge element, and a stop mechanism, wherein: the tubular body comprises: an axial cavity configured to house the drive tube, the axial cavity spanning a length of the tubular body; and at least one guide channel configured to at least partially house the blade element and the wedge element, the guide channel comprising an opening in the tubular body that opens into the axial cavity; the drive tube comprises at least one longitudinal groove axially disposed along a length of the drive tube; the wedge element comprises: a first side having at least one lateral projection configured to axially slide into the longitudinal groove to couple the wedge element to the drive tube; and a second side configured to slideably couple the wedge element to the blade element; the stop mechanism comprises a threaded sleeve configured to screw onto the drive tube to lock the wedge element in the longitudinal groove once the lateral projection is slid into the longitudinal groove; and once the stop mechanism locks the wedge element into the longitudinal groove the drive tube is operable to raise the blade element out of the guide channel by moving along the length of the tubular body.