Patent ID: 7654344

Claim:
In a drill string that extends along an axis from an uphole direction to a downhole direction, a torque converter comprising: upper and lower cylindrical string parts, each comprising an uphole end and a downhole end; helical spring elements operatively connecting the downhole end of the upper cylindrical string part to the uphole end of the lower cylindrical string part; wherein the helical spring elements limit otherwise free relative axial and counter-rotational movement of the upper and lower cylindrical string parts with respect to each other; wherein relative counter-rotational movement of the upper and lower cylindrical parts in a first direction causes the helical spring elements to contract along the axis, and thus move the lower cylindrical string part in the uphole direction; wherein relative counter-rotational movement of the upper and lower cylindrical parts in a second, opposite direction causes the helical spring elements to expand along the axis, and thus move the lower cylindrical string part in the downhole direction; and wherein a predetermined amount of torque applied to the drill string during drill string operation causes relative counter-rotational movement of the upper and lower cylindrical parts in the first direction and thus results in movement of the lower cylindrical string part in the uphole direction.