Drill string shock sub

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.

Dependencies are inferred from the claim text.