Patent ID: 7805997

Claim:
A method for detecting the presence of a crack in a shaft, the shaft including at least a first preformed weakened portion, disposed at a first distance from an end face of the shaft, and a second preformed weakened portion, disposed at a second distance from the end face of the shaft, the method comprising the steps of: exposing the end face of the shaft while the shaft is located within the machine, scanning the end face of the shaft with a test probe of a flaw detection apparatus to obtain a first echo signal having a first peak amplitude corresponding to the first preformed weakened portion and denoting a first angular reference location, moving the test probe to a second angular reference location, disposed at a known angular distance from the first angular reference location, obtaining a second echo signal having a first peak amplitude corresponding to the second preformed weakened portion at the second angular reference location, moving the test probe to a third angular reference location, disposed opposite the second angular reference location at a known angular distance from the first angular reference location, obtaining a third echo signal having a first peak amplitude corresponding to the second preformed weakened portion at the third angular reference location, and determining whether a second peak amplitude is present in the second echo signal obtained at the second angular location or whether a second peak amplitude is present in the third echo signal obtained at the third angular reference location.