orthocentric quadrangle

Any Ⅱ level planar mechanism are regarded as some closed quadrilateral connecting each other, and every capsheaf of the closed quadrilateral is the instantaneous center of connected links, so the opposite centric quadrilateral is formed.

而每个四边形的角顶,均是邻边(杆)之间的速度瞬心,从而组成对心四边形。

It is l opposite centric quadrilateral".

本文阐述了求机构中不相邻两构件间速度瞬心的一种新方法，即“对心四边形法”。