| 摘要 |
A drafting instrument for tracing ellipses and other curves adapted for the use with templates of such curves, comprising a set of links pivotally connected at each end, and disposed in parallel to constitute two pairs of opposite sides of rhombus link mechanism. The rhombus link mechanism carries in one vertex a needle point for piercing a graphic surface on which a curve is to be retraced for free pivotal movement of the mechanism about this center. Stem secured in other opposite vertex for being constrained along a cutout edge of a template. Two sliding members are respectively supported in grooves on the pair of opposite links. Said slide members are linked together for correlated movement, therein. A stylus guide member is supported by the link for tracing the curve on the graphic surface.
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