Patent ID: 7182133

Claim:
A tubular string feature locator for detecting when a selected characteristic on a tubular string suspended in a well has a preselected vertical relationship to a rig elevator, the locator comprising: sensor means to detect at least one characteristic of the tubular that has a known vertical relationship to a location on the tubular selected for gripping with elevator mounted tubular gripping means and to produce an output signal when the characteristic is sensed; and a sensor mounting arrangement that places the sensor means the same distance and direction from the elevator tubular gripping means as the known distance and direction between the characteristic to be sensed and the location on the tubular selected for gripping, wherein the sensors are arranged with at least two vertically adjacent sensors on different vertical locations, and wherein the sensors collectively accommodate lateral movement of said tubular, both sensing the movement, and the feature change being sensed when one sensor detects tubular string features the other sensor does not detect.