Abstract: Provided is a drilling tool that includes a tubular body defining a longitudinal axial cavity extending therethrough. The tubular body also defines at least one radial guidance channel extending radially from the axial cavity through the tubular body. A cutter element is disposed in the at least one radial guidance channel and includes an internal surface inclined at an angle to a longitudinal axis of the tubular body. The drilling tool also includes a wedge element having an external surface configured to engage the internal surface of the cutter element and to direct the cutter element from a retracted position to an extended position as the wedge element moves from a first position to a second position.

Abstract: A bore hole underreamer is provided having a hollow body with a longitudinal axis, which has an external wall, at least two cylindrical bores provided through the external wall and whose axes are transverse to the longitudinal axis. Each of the bores have a cylindrical widening arm for widening the hole, which is arranged in the bore like a hydraulic piston, so as to be able to slide therein between an active position and an inactive position. The underreamer has a locking member which can occupy a locking position in which this member locks the arms in their inactive position, and which, when it is released, can leave the locking position under a thrust from at least one of the arms subjected to the pressure capable of pushing the arm into its active position.

Abstract: Provided is a bore hole underreamer, intended in particular for oil drilling. The underreamer has a hollow body and at least two cylindrical bores. The bores are distributed over the circumference of the hollow body and each bore contains a cylindrical widening arm. Each arm has a bladed cutting end disposed on the outside of the body that slides between active and inactive positions. Another end of each arm is disposed inside the body and receives fluid pressure for pushing the arm into the active position. The underreamer includes a locking member for locking the arms in their inactive position when the locking member is immobilized in the body in a releasable fashion in a locking position. When released, the locking member leaves the locking position under a thrust from at least one of the arms subjected to the pressure capable of pushing the arm into its active position.

Abstract: A bore hole opener for enlarging a bore hole includes a longitudinal body, a duct for drilling fluid, formed longitudinally in the body, having a fluid passage cross-section of inside radius i, and at least two hole-opening arms, borne by the body, which have an active part equipped with cutting mechanisms, which are arranged therein in such a way that they can slide between a position of rest in the body and an active position partially out of the body, and which are guided and supported for this purpose in the body over a distance g and which, in the active position, project from the body by a length o, in which the values of i, g and o are chosen to simultaneously satisfy the conditions i+g+o S;

Abstract: Bore hole underreamer in a terrestrial formation, intended in particular for oil drilling and especially to be fixed in the vicinity of a drill head, the underreamer having a hollow body (1), with a longitudinal axis (3), which has an external wall (5), at least two cylindrical bores (7) provided through the external wall (5) and whose axes (9) are transverse to the longitudinal axis (3), the bores being distributed over the circumference of the hollow body, and in each of the bores, a cylindrical widening arm (11) which has a cutting end (13), disposed on the outside of the body and provided with blades (15) for widening the hole, which is arranged in the bore like a hydraulic piston, so as to be able to slide therein between an active position in which this cutting end (13) is distant from the body, and an inactive position, and whose other end, inside the body, is intended to receive from a fluid a pressure capable of pushing the said arm into its active position, the underreamer having a locking member (2

Abstract: Provided is a bore hole underreamer in a terrestrial formation, intended in particular for oil drilling. The underreamer has a hollow body and at least two cylindrical bores. The bores are provided through an external wall of the body and have axes that are transverse to a longitudinal axis of the body. The bores are distributed over the circumference of the hollow body and each bore contains a cylindrical widening arm. Each arm has a bladed cutting end disposed on the outside of the body that slides between active and inactive positions. Another end of each arm is disposed inside the body and receives fluid pressure for pushing the arm into the active position. The underreamer includes a locking member for locking the arms in their inactive position when the locking member is immobilised in the body in a releasable fashion in a locking position.