Strain transducers

摘要

A strain transducer of the kind in which a plug is inset into a workpiece surface requires an accurate interface fit with a drilled hole. One method proposes an oversize hole (12) which first receives an annular insert (14) in whose aperture (15) the transducer plug is a precision fit. The outer cylindrical surface of the insert has axially parallel serrations (16) which bite into the sides of the hole. Another method also has an oversize hole (22) whose mouth is constricted by a cylindrical punch (25) around a precision mandrel (24) which is then replaced by the transducer plug (28). Serrations (35) may alternatively be provided directly on the transducer plug (32), which can then be driven into a drilled hole (36) of only approximate accuracy.