ADJUSTABLE FRAME FOR OPTICAL OBSERVATION APPARATUS

摘要

The invention contemplates a support stand having a weight-compensating four-bar linkage in the form of an elongate parallelogram, for adjustable-elevation support of an observation instrument such as an operation microscope. Weight compensation is achieved by a preloaded spring contained within opposed channels which constitute two elongate members of the linkage and which have nesting side walls to complete the enclosure of the spring, while also accommodating such electrical and optical cable connections as may be needed to communicate between the instrument and the base of the stand.