Has anyone built anything large with a Sarrus linkage?

gplus
discussion
(Brandon Heller) #1

Has anyone built anything large with a Sarrus linkage? I’ve seen this page plus the printer on Thingiverse built with them, but other than that, nothing. I’m curious what level of flatness to expect as the mechanism raises up.
http://reprap.org/wiki/Sarrus_Z_Linkage

(Mark Fuller) #2

The parallelism between top and bottom is limited to your hinge accuracy. The accuracy also gets worse as the end plates get closer, due to the hinge plates being in a position where they can twist more easily.

(Nicholas Seward) #3

I have some ways to use the power of parallelograms to ensure the parallelism as @Mark_Fuller put it. The problem is that the number of joints becomes ridiculous. Let’s not give up. There have to be some elegant solutions out there.

(Brandon Heller) #4

Two DLCJs might replace a dual parallelogram arrangement for a linear axis. Was wondering @Nicholas_Seward - do you have any parts files out for those? Never seen one in person.

(Nicholas Seward) #5

@Brandon_Heller A DLCJ is nothing special. It is just two cylinders lashed together with a figure-8 pattern of string. To answer your questions, I don’t have any files that would do anyone any good. Depending on the problem, I could suggest a solution. A DLCJ version of http://youtu.be/7JIbpxUJEFA could be pretty sweet.

Side note: we are surrounded by many flat objects called tables and floors. It could be easy to get linear motion if we let these surfaces work for us.