Patent ID: 8459375

Claim:
An expandable apparatus for use in drilling or enlarging a borehole in a subterranean formation, comprising: a tubular body having at least one opening in a wall of the tubular body and having a drilling fluid flow path extending therethrough; at least one member positioned within the opening in the wall of the tubular body, the at least one member configured to move between a retracted position and an extended position; a push sleeve assembly disposed at least partially within the tubular body and coupled to the at least one member, the push sleeve assembly comprising: a push sleeve configured to move axially upward responsive to a pressure of drilling fluid passing through the drilling fluid flow path and acting on a radially extending exterior surface of the push sleeve within an annular chamber in communication with the drilling fluid flow path and located between the push sleeve assembly and the tubular body to extend the at least one member into the extended position, the push sleeve also being configured to move axially downward in response to a pressure of drilling fluid within the drilling fluid flow path acting upon a restrictive element disposed within the drilling fluid flow path to retract the at least one member into the retracted position; at least one interior protrusion axially below the at least one member sized and configured to retain the restrictive element within a fluid passageway at a first fluid pressure and to release the restrictive element at a second fluid pressure greater than the first fluid pressure; and at least one fluid port axially above the at least one protrusion and axially below the radially extending exterior surface and communicating between the fluid passageway and the annular chamber.