Patent ID: 8960324
Filing Date: 2015-02-24
Classification: E21B

Abstract:
1. A top drive system, comprising: a top drive comprising a proximity sensor disposed in a housing thereof; a portion of the top drive coupled to elevators through load transfer springs such that axial loading applied to the elevators results in relative axial movement between a link load collar coupled to the elevators and a load ring coupled to a drive shaft, the proximity sensor mounted to a part of the top drive wherein the relative axial movement between the link load collar and the load ring results in change in distance between the proximity sensor and another part of the top drive such that the relative axial movement between the link load collar and the load ring results in a change in signal output thereof; and a processor configured to operate a drive shaft motor rotationally coupled to the drive shaft, the processor in signal communication with the proximity sensor, the processor configured to disable rotation of the motor when the relative axial movement between the link load collar and the load ring is indicative of axial loading on the elevators.