Patent ID: 7415363
Filing Date: 2008-08-19
Classification: G01L

Abstract:
1. An apparatus with a rotatable shaft having at least one first target coupled on the rotatable shaft so as to rotate therewith and at least one second target coupled on the rotatable shaft so as to rotate therewith, an axial location of the first target along the rotatable shaft being different than an axial location of the second target along the rotatable shaft, comprising: at least one first horizontal first probe for transmitting a first horizontal first transmission signal to the first target and receiving a first horizontal first response signal from the first target; at least one first horizontal second probe for transmitting a first horizontal second transmission signal to the first target and receiving a first horizontal second response signal from the first target; at least one second horizontal first probe for transmitting a second horizontal first transmission signal to the second target and receiving a second horizontal first response signal from the second target; at least one second horizontal second probe for transmitting a second horizontal second transmission signal to the second target and receiving a second horizontal second response signal from the second target; a first vertical first probe for transmitting a first vertical first transmission signal to the first target and receiving a first vertical first response signal from the first target; at least one first vertical second probe for transmitting a first vertical second transmission signal to the first target and receiving a first vertical second response signal from the first target; at least one second vertical first probe for transmitting a second vertical first transmission signal to the second target and receiving a second vertical first response signal from the second target; at least one second vertical second probe for transmitting a second vertical second transmission signal to the second target and receiving a second vertical second response signal from the second target; an axial location of the first horizontal and vertical first and second probes along the rotatable shaft being different than an axial location of the second horizontal and vertical first and second probes along the rotatable shaft; and a processor operatively coupled to each of the first and second horizontal and vertical first and second probes for determining a torsional displacement of the shaft based at least on the first and second horizontal and vertical first and second response signals received by the first and second horizontal and vertical first and second probes, respectively.