I'm trying to figure out a solution to this design. I want to add a spring to this joint so it can flex up and down and I want the neutral position to be at 45 degrees as pictured. So if you push it either way it springs back to this position. At the same time I dont' want the arm to bounce around so I want to make this 45 degree position sticky. Perhaps a detent could hold it in place until pushed beyond a certain tension. So I'm looking for ideas as to how I can 1. add spring tension to the joint and 2. have a sticky point. Any ideas would be appreciated. Feel free to modify the drawing I made if you're feeling motivated. Or if you can think of some examples where something like this has been done, please let me know. Thanks!