Abstract: According to one embodiment of the invention, a saver sub for a steering tool includes a main body having an external thread portion adapted to threadably couple to a box end of the steering tool and an internal thread portion adapted to threadably couple a drill bit thereto and a thread shoulder having an outside perimeter and an inside perimeter disposed around a perimeter of the main body. The thread shoulder includes a curved portion associated with the inside perimeter and a tapered portion extending from the curved portion to the outside perimeter and tapering toward the external thread portion.

Abstract: In a drill string pressure pulses are generated by expansion and constriction of an elastic body to transmit information along the drill string.

Abstract: The present invention provides an apparatus for orienting a drilling tool in a borehole, and which employs drilling mud pressure to selectively hydraulically move force-transmitting elements associated with pressure members on the exterior of the tool against the wall of the borehole, or to radially shift the drive shaft of the drilling tool in the tool casing. The tool may also include a drilling mud powered centering mechanism for maintaining the tool or the drive shaft within the tool in a centered basic position. A tool may include both pressure members and a shiftable drive shaft, as well as centering mechanisms to act on both the pressure members and the drive shaft.

Abstract: The present invention discloses a drilling tool apparatus and method for sinking drill holes in underground rock formations while using a selectable direction profile for the drill hole.

Abstract: The present invention discloses a double guided slide valve apparatus for producing pressure pulses in drilling mud medium flowing through a drill string casing.

Abstract: The apparatus for the generation of pressure pulses in a drilling mud composition which flows downward in a drill string (1) is composed of a valve (V) inside the drill string (1), with a stationary, braced, tubular exterior housing (3), tubular primary valve (4) which can be translated from a lower starting position against the flow direction (2) of the drilling mud composition into an upper operational end position, a stationary, tubular support (5) in a coaxial position inside primary valve (4), and a pilot valve (13), (14) actuated by motor means (15). Exterior housing (3) and primary valve (4) define a constricted segment (29) whose flow cross section can be modified by the position of primary valve (4), and primary valve (4) and the support (5) surround an interior flow channel (21), (12) and (10), which can be opened and closed by outlet orifice (13) of pilot valve (13), (14).