Pressure activated release member for an expandable drillbit

Abstract

An apparatus for use in a wellbore. The apparatus includes a body and a blade assembly. The blade assembly is movable between a collapsed position whereby the expandable apparatus has a smaller outer diameter and an expanded position whereby the expandable apparatus has a larger outer diameter. The apparatus further includes a pressure activated member for selectively allowing the blade assembly to move from the closed position to the open position. A method for using the apparatus, wherein a drill string with an expandable bit at the end thereof is lowered into the wellbore. Thereafter, the pressure activated member is activated to allow the cutting members to move from the collapsed position to the expanded position. Subsequently, the expandable bit is rotated to form a portion of the wellbore. Next, the expandable bit is deactivated and the cutting members are moved from the expanded position to the collapsed position.

Dependencies are inferred from the claim text.