Miniaturization of a 50Â N tuning-fork type force transducer by adopting a simplified Roberval mechanism

A tuning-fork type force transducer of 50 N rated capacity was miniaturized and packed into a cylindrical space 70 mm in diameter and 92 mm in height by adopting a simplified Roberval mechanism. Repeatability and reproducibility of the measured results in different rotational positions of the transducer were within 2 × 10−5 relative. The mass of the force introduction part was reduced, and this enabled the transducer to be used in an inverted orientation, which is indispensable for the reference force transducers built into force comparators. The new compact force transducer was evaluated in its upright orientation by using a dead-weight type force standard machine and in the inverted orientation by using a force comparator in which an existing massive tuning-fork type force transducer was temporarily adopted as a reference. It was demonstrated that the output of the new force transducer in the inverted orientation coincided with that in the upright orientation within a mean deviation of 3 × 10−5 relative, after applying nonlinearity compensation.