Patent ID: 7997357
Filing Date: 2011-08-16
Classification: E21B,F16F

Abstract:
1. A spring assembly for use in a drill string having a drill bit comprising: a first member capable of being mechanically coupled to the drill bit so that the first member can translate in a first direction and an opposing second direction in response to the movement of the drill bit in the first and second directions; a second member mechanically coupled to the first member so that the first member can translate in relation to the second member in the first and the second directions; a spring stack disposed on one of the first and the second members, wherein a first end of the spring stack is substantially restrained and a second end of the spring stack translates in the first direction when the first member translates in the first direction in relation to the second member so that the spring stack is compressed, and a second end of the spring stack is substantially restrained and the first end of the spring stack translates in the second direction when the first member translates in the second direction in relation to the second member so that the spring stack is compressed, whereby the compression of the spring stack exerts a restoring force on the drill bit when it moves in both the first and second directions, wherein the spring stack comprises a first spring and a second spring positioned in series; a first and a second spacer, wherein the first end of the spring stack urges the first spacer toward a coupling of a torsional bearing assembly when the first member translates in the first direction in relation to the second member so that the coupling restrains the first spacer and the first end of the spring stack, and the second end of the spring stack urges the second spacer toward a casing of a compensation module connected to the spring assembly when the first member translates in the second direction in relation to the second member so that the casing of the compensation module restrains the second spacer and the second end of the spring stack.