Excel Belleville Spring Calculator

Belleville Springs (aka “Belleville Washers”, “Spring Washers”, or “Disk Springs”) are wonderfully useful mechanical devices, but with one minor drawback – their properties are difficult to calculate – until now!  Almen and Laszlo were the first to develop a workable calculation method, but it can only loosely be described as “workable.”  (This is the method…

Friction Factor Calculation in Excel

Happy 4th of July Everybody! When in the course of human events it becomes necessary to calculate the Darcy-Weisbach friction factor… engineer’s often throw up their hands, go back to their old college textbooks, and say “about .02!” [Which normally isn’t off by more than a factor of 2 in either direction.] If you want…

Spring(s)!

Spring is in the air!  The fruit trees are blooming in the back yard and the fresh breeze is coming in gently from the newly opened windows.  With all that going on it’s hard for an engineer to keep his mind off of spring… or springs, for that matter.  Flowers and fresh air are certainly nice,…

Exact Constraint to the Rescue!

A client recently requested a repeatable positioning device for a bio-medical system.  Normally, this is a ‘turn the crank’ design, where the biggest challenge is sorting through previously-used kinematic configurations and applying the most appropriate one.  This project was more interesting though.  First of all, the environment precluded the use of springs, pins, and metal…