The 4-106 features solid construction, affording excellent wear resistance and minimum sliding friction.
Two models of the 4-106 Vibration Transducer have maintained a prominent position in the study of vibration. As a result, much of the early test instrumentation was standardized on their use. Several jet-aircraft engine manufacturers used these early instruments almost exclusively for vibrational analysis in testing.
Externally both models of the 4-106 are similar, but internal construction and damping differ since the 4-106-0001 measures vertical vibration and the 4-106-0002 requires mounting on a horizontal plane. The stabilized permanent-magnet seismic mass is coupled to the case by coil springs, riding on Nitralloy bushings over a highly polished, hard-chromed, stainless steel shaft.
This construction affords excellent wear resistance and minimum sliding friction, a combination insuring long life and good sensitivity at low frequencies. The case is made of cast aluminum to combine strength with minimum weight
Four mounting holes accommodate standard No. 8 fillister-head screws for attaching the transducer to vibrating body, and two screw-terminals on the top are provided for cable attachment.