Abstract: Apparatus for directional drilling in the earth comprises a down hole motor having a stator housing adapted to be connected to a string of drill pipe at one end and having a rotor shaft extending out the other end. The rotor shaft is adapted to receive and drive any suitable rotary bit. The stator housing is provided with fulcrum means in the form of a barrel member having arcuate longitudinal cross section. The fulcrum member is of substantially the same size as the hole being bored and is engageable with the side wall of the hole to provide a fulcrum about the drilling motor can be turned to change direction. A suitable deflection means is positioned at the end of the stator housing adjacent to the connection to the drill string and includes a laterally moveable thrust member which is operable to engage one side of the hole being drilled to deflect the stator housing in the opposite direction and pivot the same on the fulcrum point to change the direction of the hole being drilled.

Abstract: A shock sub for a well drilling string comprises a tubular housing adapted to be connected to one part of a drill string and a mandrel extending longitudinally into the housing and having an end portion adapted for connection to another part of the drill string. The mandrel and housing are shaped to define a non-circular annular cavity there between when assembled together. A compressible elastic metallic spring means is positioned in and substantially fills the non-circular annular cavity and is compressible longitudinally, radially and circumferentially to absorb longitudinal, radial and torsional vibration and impact loads and to transmit rotary movement between said housing and mandrel for imparting rotation from one part of the drill string to the other part connected by the drill sub. The spring means is preferably a knitted wire fabric or rope compressed into a compact mass capable of spring deflection in longitudinal, radial and circumferential directions relative to said shock sub assembly.