I’ve used Algodoo for (very occasional) linkage design. It’s not ideal, really more of a toy than a tool. I’m going to go through the options in this post and the comments and see if I can ...

Design software that augments our mechanical design capabilities is a rare gem on these pages, and this one is no exception. If your curious to play with other useful linkages simulating tools ...

This discussion will focus specifically on the "push-off' GM mechanical linkage design, since it is the most popular, but there's information here for Fords and Mopars too.

The mechanical linkage between the load and motor in a gear drive, Figure 4, ... Aerodynamic Design: Balancing Material Composition with Manufacturing Methods. Engineering for Impact.