Sarrus Linkage Linear Bearing

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.