Apparatus for controlled absorption of axial and torsional forces in a well string

Abstract From the Canadian patent

A drill string apparatus for the controlled absorption of both axial and torsional forces exhibited on the well string during drilling operations. The device is adapted to be connected in the drill string above the drilling tool in order to control the forces acting on the bit and to arrange the mean weight on bit for the selected drilling operation. Generally, the apparatus includes an outer casing coupled at its upper end to the drill string and an inner assembly telescopically received within the outer casing and connected at its lower end to the lower part of the bottom hole assembly or the drilling tool. Rotational torque is transferred from the drill string and outer casing to the …