Sarrus linkage linear bearing

This is an implementation of the Sarrus linkage that may be useful for reprap type machines. It is made from ABS printed on my repstrap, with 1/16" (1.6 mm) brass rods for the hinge pins and 4-40 screws to hold the spine sections together. The hinge pin holes were chased with a 1/16 drill bit, and the screw holes with a 1/8" bit. The two ends are made of one center block cut in half with a saw, and there are some other holes that were drilled rather than printed.

It has a total swing of 100 mm. This is set by the length of the spine, and could easily be 110 mm. It moves very smoothly, and was stiffer than I thought it would be. The center block only moves down about 0.2mm with a 460 gram payload. Interestingly the droop is about the same over the whole range of motion. It stays well within 0.2mm of a straight line as it moves.

A payload (extruder?) could mount on the central block, which could be widened.