Patent ID: 7210360
Filing Date: 2007-05-01
Classification: G01L

Abstract:
1. An apparatus for measuring relative displacement between a first end and a second end of a shaft the first and second ends being centered on a shaft axis, comprising: a first ferromagnetic plate having a first side and a second side and being connected to the first end, the first ferromagnetic plate being centered on the shaft axis and having a plurality of ferromagnetic teeth extending from the first side and in a first direction parallel to the shaft; a second ferromagnetic plate having a first side and a second side and being connected to the second end, the second ferromagnetic plate being centered on the shaft axis, the first and second ferromagnetic plates forming a gap; a plurality of permanent magnets having a magnetic field and being coupled to the first side of the second ferromagnetic plate, the magnets extending in a second direction, the second direction being opposite the first direction; a first sensing device disposed within the gap for sensing a magnetic flux of the magnetic field; and the first ferromagnetic plate having a circular cross-section and a circumferential flange extending from an outer edge of the first ferromagnetic plate in the first direction and located radially distal from the plurality of ferromagnetic teeth.