|
Little update on this project. Unfortunately the arm simplesez has is not the one I need, and the knuckle pieces are different for the right and left arms.
I ordered a torsion spring off of Mcmaster to try out. In an effort to keep modifications to the current functioning parts to a minimum my constraining dimension was the width of the previous knunckle, around 0.9". That led meant the strongest spring I could get was 25lbs. I was skeptical that it would be strong enough, but it was like $2.50 plus shipping so I ordered two of them to give it a try.
I machined a little teflon sleeve to slip over the dowel pin and inside the spring to clean up the slop on the ID. I used the dimension on the mcmaster spec sheet for the OD of the sleeve which turned out to be way too small.
My skepticism proved to be right, and the spring wasn't even close to strong enough. The weight of just the arm was enough to keep it closed on its own. I then realized that I probably needed to install the torsion spring under load, in which case I had the wrong spring. So back to mcmaster.
In the meantime one of my buddies came by and asked why I didn't just try and fix the broken knuckle. I had some JB weld in the tool box so I figured I might as well give it a go. Pretty sure this won't be strong enough given the amount of tension the arms are under, but it doesn't hurt to try.
|
Linear Mode
