Patent ID: 6808455
Filing Date: 2004-10-26
Classification: F16D,F16F

Abstract:
A torsional shock absorber for dampening rotary shock loading on a drill string, comprising:an outer housing having one end adapted to be connected into the drill string; the outer housing having drive splines on an inner surface; a mandrel having one end adapted to be connected into the drill string, the mandrel extending into the outer housing and having drive splines on an outer surface of the mandrel that fit between the drive splines on the outer housing; a dampening bar positioned between each of the splines of the outer housing and each of the splines of the mandrel, the dampening bars being formed of a material to absorb shock from torsional loading at a drive interface between the splines of the outer housing and the mandrel; a thrust bearing operably located between the outer housing and the mandrel for transferring axial thrust and tensile loads between the outer housing and the mandrel and avoiding the transfer of thrust to the dampening bars a pair of first shoulders, one on the mandrel and one on the housing, that engage a first side of the thrust bearing: a pair of second shoulders, one on the mandrel and one on the housing, the second shoulder on the mandrel engaging a second side of the thrust bearing, so that axial thrust passes between the first shoulder on the housing, the thrust bearing and the second shoulder on the mandrel; and an annular retainer surrounding a portion of the mandrel and being rotatable relative to the mandrel, the retainer having a first end that engages the second side of the bearing and a second end that engages the second shoulder of the housing, so that an axial tensile load passes between the housing, through the second shoulder of the housing, the retainer, the thrust bearing, and to the first shoulder of the mandrel.