Patent ID: 6782594
Filing Date: 2004-08-31
Classification: B23P,B25B,G01L,Y10T

Abstract:
A method for comparing relative clamp loads between a plurality of previously installed threaded fasteners comprising:providing a plurality of previously tightened threaded fasteners; applying an additional torque in a tightening direction a first of the tightened threaded fasteners until a break away torque is reached; measuring the torque values applied to the first previously tightened fastener and measuring the angle through which the first fastener rotates; defining a first zero-angle point to be a point at which a tangent from a torque versus angle plot, created from the measured torque and angle values from the first previously tightened fastener, crosses an angle axis; defining a first audit angle to be the angle between the first zero-angle point and the angle associated break away torque for the first previously tightened threaded fastener; applying an additional torque in a tightening direction a second of the previously tightened threaded fasteners until a break away torque is reached; measuring the torque values applied to the second previously tightened fastener and measuring the angle through which the second fastener rotates; defining a second zero angle point to be a point at which a tangent from a torque versus angle plot, created from the measured torque and angle values from the second previously tightened fastener, crosses an angle axis; defining a second audit angle to be the angle between the second zero angle point and the angle associated break away torque for the second previously tightened threaded fastener; and comparing the first and second audit angles to determine relative clamp loads.