Probe holder for a machine body position sensor, with means to increase its natural frequency

Claim 1

In an assembly for holding a sensing device operable to electrically observe the position of a body contained within a rotary machine over a defined air gap, including a mounting structure secured to the outside of the machine and having a generally elongated cylindrical housing section extending through an opening in said machine, the improvement comprising: a removable probe holder supported in cantilevered fashion within said mounting structure, the elongated free end of said holder extending substantially coaxial within said elongated housing section and terminating in closely spaced relation to said observed body, said holder having a pair of spaced circumferentially extending grooves formed on the outer surface thereof in proximity to said free end thereof, said grooves being relatively closer to the free end of said holder than to the supported end thereof, the space between said grooves being at least three-fourths of an inch, each of said grooves having a resilient ring provided therein, with the outer surface of each of said resilient rings being in contact with the inner surface of said housing section to provide a resilient support structure for said holder within said housing said rings being designed to increase the natural frequency of the holder above the second harmonic of the maximum machine running speed.