Instrument for tracing curved figures particularly ellipses

摘要

A hand-held compass-type instrument for tracing curved figures, particularly ellipses, is described comprising a manipulatable finger- gripping element; an anchor arm pivotably mounted at one end to one end of the finger-gripping element, the opposite end of the anchor arm being adapted to be anchored to the surface on which the curved figure is to be traced; a tracing arm pivotably mounted at one end to the finger-gripping element, the opposite end of the tracing arm being adapted to trace the curved figure; and an eccentric linkage, having presettable means for presetting its eccentricity, coupled between the anchor and tracing arms for constraining the tracing arm to pivot in a presettable eccentric manner with respect to the anchor arm when the finger-gripping element is manipulated to trace the figure.