Abstract: A linear variable inductance transducer of the kind in which a spring-loaded plunger containing a magnetic core is axially movable in a stationary housing containing a coil assembly has the external surface of the plunger made of ceramic material, guided linearly solely by sliding in a ceramic bearing sleeve in the housing. The bearing sleeve may itself be flanged to form a bobbin for the coil assembly.

Abstract: A bore gauge incorporates one or more electromagnetic transducers housed in a shroud which in use is inserted into the bore to be gauged. Each transducer comprises a coil and a core movable within the coil. In one embodiment the coil and the core of a single transducer are mounted on opposite limbs of a flexible fork-like structure, the two limbs carrying gauging contacts for engagement with the walls of the bore. In other embodiments, incorporating a plurality of transducers, coils are rigidly mounted within the shroud and cores are mounted on flexible limbs set in slots in the surface of the shroud.

Abstract: A variable inductance transducer for use in engineering metrology comprises a plunger with a tip and carried in a housing in linear bearings with a core mounted on the plunger within the overall axial length of the bearings, so as to produce an axially compact structure. The bearings can be two separate ball bushings with the core disposed between them.