What is "dynamic load"?

[georgebarr]

I am thinking about buying anti-backlash Acme Nuts/Screws from:
http://www.kerkmotion.com/products/s...s-overview.asp
They listed the entire assembly as having a dynamic load of 100 lbs. My question is what does dynamic load mean? Is this the maximum amount of force the Acme screws can handle while pushing the table side to side? Or, is it the amount of weight of the moving table itself and anything sitting on the table.

I am concerned that the max. dynamic load might not handle my 5' x 7' router built from 3"x3"x0.25" mild steel tubing. I plan to use rapid speeds of 200-300"/minute.

[gtd107]

Static Load in simple terms is the amount of force an item can withstand with no movement.

Dynamic Load is when the item has overcome the force of friction (and other forces) and is in motion.

So when you are talking about a nut, The nut can safely move with 100 lbs or less of force while it is in motion.

100 lbs, also has a factor of safety built in by the manufacturer. It is possible to move more than 100lbs, but is not recommended. Anymore than 100 lbs will cause excessive wear on the threads and possibly fail.

[ger21]

Their 3/4" VFD series are rated for 350lbs dynamic load. I'm guessing your gantry will weigh 150lbs or so, and acceration will put a higher load on the screws/nuts.

[energyforce]

I would look into whether or not 100lbs stands for tensional dynamic loads or shear dynamic loads. I have absolutely no idea. If I had to guess I think it would be for pure tensional dynamic loading. Also preloading for dynamic loads is higher than that for static loads.

I have not gone to that link yet, dont have time right now. It is better practice to rely on close-fitted dowel pins to take shear loads and let the threaded fasteners provide the tension to hold the joint together.

Erik